DWYER INSTRUMENTS, INC.

Customer ServiceFast, friendly customer service professionals are available to

process and provide assistance with your order – whether itis by phone, fax, e-mail or through our website.

Technical SupportHave an application question? Our technical supportprofessionals are trained to provide you with theanswers you need.

Prompt ShipmentsAfter you place your order, Dwyer’s dedicated shipping staff packs and ships your order promptlyand completely –within 24 hours on most in-stockitems.

WebsiteDwyer Instrument’s website delivers the convenienceyou want. Go to www.dwyer-inst.com for the most

complete ordering and product support information atyour fingertips – anytime, day or night. Installation and

operating manuals are available on products that areeasily downloadable to your computer or printer.

Total customer service the way you need it.

Address:Dwyer Instruments, Inc.102 Indiana Highway 212P.O. Box 373Michigan City, IN 46361 U.S.A.

Telephone:(800) 872-9141(219) 879-8000

Fax:(219) 872-9057

e-mail:General: info@dwyer-inst.comLiterature: lit@dwyer-inst.comTechnical: tech@dwyer-inst.comQuotes: quotes@dwyer-inst.com

website:http://www.dwyer-inst.comhttp://www.love-controls.comhttp://dwyer-inst.com/retailhttp://proximitycontrols.com

Founded in 1931, Dwyer Instruments, Inc. produces a broad range of competitively pricedprecision instruments for measuring, transmitting and controlling pressure, temperaturelevel, flow and related applications.Many of these instruments are widely know by their individual brand names, such asMagnehelic® and Spirahelic® pressure gages, Photohelic® switch/gages, Rate-Master® andVisi-Float® flowmeters and Hi-Flow® valves. Divisions include well-known brand names suchas Mercoid, W.E. Anderson, Proximity Controls and Love Controls.Headquartered in Michigan City, Indiana, the company has four more Indiana manufacturingfacilities, as well as manufacturing facilities in Anaheim, California; Fergus Falls, Minnesota;Kansas City, Missouri; and Naguabo, Puerto Rico.In addition to making and selling quality precision instruments, Dwyer is committed to a stan-dard of customer service – including competitive prices and knowledgeable, courteous tech-nical support – that generates and sustains long-term relationships.

Dwyer Instruments, Inc.accepts Visa® and

Mastercard®.

1

introduction

To help engineers solve design, manufacturing and physicalplant problems, Dwyer Instruments, Inc. has developed thisEngineering and Product Applications handbook. When suchproblems involve the measurement or control of gage or differ-ential pressure, temperature, level or flow, chances are there isa Dwyer Instruments product that can provide the solution.Reviewing the applications illustrated in this handbook may trig-ger an idea for a new approach to solving your engineeringproblems. For design engineers, these applications may alsosuggest ways to solve a customer problem and become thebasis for a new product development.The information contained in this handbook may also suggest amore reliable, convenient and lower cost approach whenreworking an existing product or system design. In many casesthe application suggestions may cut costs by increasing effi-ciency through continuous control of systems and processes. The Engineering and Applications handbook also illustrates howengineers and technicians find applications for Dwyer controlsand gages on a wide range of products serving a broad spec-trum of industries and markets.The Dwyer Instruments, Inc. full-line catalog and its websitesdeliver the convenience and assistance you want from an instru-mentation company. Our catalogs are available to you free ofcharge via telephone, fax or websites. In addition, our websitescontain installation and operating manuals on our products thatare easily downloadable to your computer or printer.Total customer service is our goal.

Important Note:

Index

The gage and control hook-ups and sketches, and other appli-cation information shown in this Handbook are generalized andabbreviated to present the basic application idea only and noproprietary information has been revealed.We believe this application information to be reliable, but isintended for use by persons, at their own discretion, havingtechnical skill and knowledge of the business. Neither Dwyer

Instruments, Inc., nor the Mercoid, Proximity, Love Controls orW.E. Anderson Divisions, shall be liable for loss, damage, orexpense directly or indirectly arising from the use of any prod-uct described herein. In no event shall any of these Companiesbe liable for direct, indirect, special, or consequential damages.©Copyright 2003 Dwyer Instruments, Inc. No part of this hand-book may be reproduced in any form without the express writ-ten consent of Dwyer Instruments, Inc.

Dwyer Instruments, Inc. Engineering and ApplicationsHandbook

Helpful Information 1 – 4Glossary of Terms 4Products from Dwyer 5 – 7New Products 8

PressureMeasurement 9 – 12Control 12 – 24

Flow/Air VelocityAir/Gas 24 – 33Liquid 34 – 40

LevelLiquid 40 – 43, 45Process 41Control 43 – 45

TemperatureControl 45 – 49

ValvesControl 48 – 49Process 50

MiscellaneousProcess 50Analyze/Measure/Control 51

Reference 52

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helpful information

Pressure

The specified pressure ratings for Dwyer differential pressure gages,differential pressure switches, manometers, and flowmeters must becarefully observed. The Dwyer catalog lists options available for higher-than-standard pressure operation of the Dwyer Magnehelic® differentialpressure gage and Photohelic® differential pressure switch/gage. Inaddition, small safety relief valves are available for these gages. Thevalves can be teed directly into the sensing line.Pressure relief valves with adequate venting capacity should be used inany system if the supply is capable of delivering the air, gas, or otherfluid at pressures greater than the system capability. If the system gasor fluid is noxious or toxic, be sure to dispose of this material properlyby piping the pressure relief valve vent to a safe area.When pressure regulators are used to reduce high-pressure air or gasfor use in low-pressure systems, pressure relief valves should beinstalled on the low-pressure side of the regulator to protect the systemin case of regulator failure or operator error. If pressure relief valves arenot provided, pressure supply equipment should be selected with max-imum pressure capability less than that which is safe for all compo-nents in the system.

Temperature

Because of the variety of elastomers and fluids used in Dwyer differen-tial pressure controls and gages, specified operating temperatureranges for these products will vary. Pay particular attention to the tem-perature specification in the Dwyer catalog or installation and operatingmanual when you consider an application at high or low temperature.Options are available in some instances to provide for operation at lowerthan the specified minimum temperature, but such options may limitthe ranges available and reduce the permissible maximum operatingpressure.If you specify manometers using water as the indicating fluid, take careto ensure that these manometers are never used in ambient tempera-tures below freezing. Call your nearest Dwyer sales office for informa-tion if you need special products and ratings to meet temperature andpressure conditions beyond the specifications of standard Dwyer prod-ucts.

Electrical

To obtain maximum operating life, the electrical specifications forDwyer controls and gages must be carefully observed. In order to pro-vide specified performance, particularly in the low ranges, Dwyer differ-ential pressure switches utilize a microswitch with a small contact gapand low spring rate to minimize operating force and movement.Because of the small contact gap, the maximum ratings are limited toresistive AC loads. The microswitch does not have a DC rating, as thegap can maintain a DC arc when the contact is broken under load evenat very low currents.

Reliability

Ideally, all pneumatic instrument systems should work with clean fil-tered air or gas which is non-toxic and dried to a dew point well belowany ambient temperature in which the system will operate. Since thisis not always practical, it is important to remember that, with fewexceptions, air contains a substantial quantity of dirt and moisture.Over a period of time, the dirt accumulates until it plugs static tips, pitottubes, sensing lines, even the gage and switch itself.Changes in temperature in the sensing system, particularly in outdoorapplications, may cause moisture in the system air or gas to condense.The accumulated water then creates problems in the gage, control, orsensing line. Such accumulations can produce corrosion, damage dueto freezing, or simple blockage while in the liquid state. Sensing and control systems are particularly susceptible to problemswhen operating in dust laden air, corrosive and wet media such as fluegases, and the moisture laden air associated with scrubbers and dryers.In the case of dust laden air or dirty liquids, sensing lines (and ventedgage or control ports in ambient industrial conditions) should beequipped with filters having adequate surface area. The filters, as well asstatic tips or pitot tubes, should be inspected and cleaned frequently.To protect against condensation, water separators, or drop legs shouldbe installed in the sensing system at the low points where condensationwill accumulate. The drop leg need only be made of a pipe section teedinto the line and extending vertically downward from the desired loca-tion with a valve at the bottom to drain the water periodically. Using alarge diameter pipe for the drop leg increases storage capacity and min-imizes the number of times it must be drained.Corrosive gases are often both dirty and moist. They may require bothof the preceding precautions plus careful attention to compatibility withthe wetted parts of the control or gage.

As you start to design a new product or system that includes DwyerInstruments components, you undoubtedly plan to achieve maximumperformance, reliability and safety. A thorough knowledge of the char-acteristics of the Dwyer products included will help ensure the mostsuccessful result. The following recommendations are based on years of field experience.They should prove invaluable to you in specifying the most suitable andefficient components for your application.

Note these important design precautions:

Compatibility

It is important to ensure that the media coming in contact with a Dwyercontrol or gage be compatible with the materials of the wetted parts.This is necessary to prevent eventual failure of the control or gage orthe contamination of the media itself. The various materials used ascomponents of Dwyer controls and gages are specified in our catalogs.Various optional elastomers, metals, and plastics are available to meetspecific customer requirements. In addition, special cleaning of allDwyer controls and gages is required for oxygen service (except theDwyer Photohelic® differential pressure switch/gage, which is not suit-able for oxygen service).We have data available on a wide range of media regarding compatibil-ity with various stock or special products. Visit our website or call yourDwyer sales office for assistance in matters of material compatibility.

However, AC arcing associated with resistive loads is self-extinguish-ing, as the voltage goes to zero at a rate equal to the line frequency.Inductive AC loads also require significant derating of the switch. Thisis due to the high voltage surge created when the circuit is broken,resulting in heavy momentary arcing which can destroy the switchcontacts.The best solution to control DC or inductive AC loads with Dwyer dif-ferential pressure switches is the use of an appropriate interfacedevice, such as a mechanical relay or solid-state switching unit. In "dry" circuit applications, where extremely low or no current flow isinvolved, specify the gold contact option for the microswitch to ensurereliable long-term operation.

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helpful information

Safety

All of the above precautions are basic to the safe operation of any sys-tem employing pneumatic controls and gages. Particular emphasisshould be placed on these precautions when systems are operatingnear the maximum rated pressure for the components, or when thegas or fluid in the system is noxious, toxic, or combustible, or wherethe system environment itself is hazardous due to explosive fumes orgases. Dwyer offers various options and models to provide controls andgages capable of safe operation in an explosive environment. Forexample, you can order optional non-removable valve stems for Dwyerflowmeters to prevent the accidental release of pressurized or haz-ardous materials. Before using combustible gases to operate Dwyer differential pressuregages, discuss your plan with a sales engineer. Potential compatibilityand leakage problems may require a special modification for yourapplication. These gages do not have built-in restrictors normallyemployed in combustible gas equipment. Perhaps most important of all in designing a safe system is to realizethat even the most reliable component, properly specified andinstalled, can and will fail eventually. Therefore, we recommend thatsystems be designed to fail-safe, i.e., the system will shut down or theprocess will stop if any critical component fails. The system should be designed to anticipate failure due to loss ofpneumatic pressure, loss of electrical power or any other possibility offailure related to the installation. Where positive operation is essential,back-up or redundant controls and power should be provided.

Performance

In general, differential pressure controls and gages will perform bestwhen provided with the maximum differential pressure signal you canobtain in the application. Higher-range gages and controls are generally less susceptible toproblems related to vibration and shock, mounting position, tempera-ture changes and accumulation of dirt and moisture. They are there-fore easier to install and maintain. For example, when using a Dwyer

Additional Design Precautions for Mercoid Products

In general, the preceding design precautions also apply for Mercoidpressure, temperature, and level controls. However, as Mercoid prod-ucts can be applied to a wider range of media under higher tempera-tures and pressures, often in more hostile environments, the follow-ing added design precautions should be considered. As in any control application, the switch electrical specifications mustbe carefully observed. However, the availability of mercury switches inMercoid controls provides a unique advantage to the specifying engi-neer as they offer the capability for handling more demanding electri-cal loads than a snap-action switch. The mercury switch is preferredfor higher alternating or direct currents, both in resistive and inductiveloads. In addition, the sealed mercury switch offers a level of inherent pro-tection in hazardous conditions. It also provides excellent long-termreliability where control actuation is infrequent as the sealed switchconfiguration protects against contact corrosion which can causeother types of switches to malfunction. Mercury switches are also ideal for low-voltage and low-current (drycontact) circuits such as encountered in computer controlled applica-tions. However, the design engineer should give consideration to con-cerns about potential mercury contamination in switch applicationswhere this may be a factor. In applying Mercoid Bourdon tube pressure switches, the use of asurge tank, snubber and/or capillary tubing connection is recom-mended where pulsation or pressure surge cannot be avoided.Additional protection against vibration and pulsation can be obtainedby specifying the Delrin bushed movement option.

It is most important to approach pneumatic systems design with theunderstanding that, despite careful design and safeguards, everythingwill eventually become dirty, wet, or corroded. Thus a good preventivemaintenance plan is the key to maximum reliability. Where the control or gage will be installed in a harsh environment, theadded protection of a suitable housing is highly desirable. If a controlor gage must be mounted outside, exposed to the elements, it shouldbe protected as much as possible from direct exposure to the sun, rain,wind, heat, and cold. Weatherproof housings are available for mostDwyer controls and gages and certain models are inherently weather-proof. A tropicalization treatment can be ordered for Dwyer differential pres-sure switches to be installed in hot, humid environments.

Although Dwyer sales personnel can advise you regarding materialscompatibility and the proper application of Dwyer instruments andcontrols, system design is beyond the scope of their activities andthe coverage of Dwyer's product liability insurance policy. Foraspects of system design beyond the capability of the designer, wesuggest retaining the services of a consulting engineer.

Magnehelic® gage as an air-flow monitor in a ventilation system, favormeasuring total differential pressure across the blower versus sensingonly static, velocity, or even total pressure on just one side or theother. When it is necessary to repeatedly pressurize and depressurize a sys-tem, you can minimize or eliminate unwanted switch closures orannoying full-scale gage pointer deflection by placing suitable restric-tors in the line on both sides or in some cases, only the low-volumeside of the switch or gage. When using Dwyer Magnehelic® differential pressure gages orPhotohelic® differential pressure switch/gages in sensitive leak testsystems, it is best to specify our "leak test option" when ordering thegage itself. This will reduce erroneous readings due to normal slightleakage in the instrument itself. Although it is not possible to completely eliminate leakage in instru-ments with elastomer diaphragms, our special "leak test option" pro-cedures and extra care will usually reduce the leakage to an acceptablelevel. To minimize the potential for gage error due to a shift in the zero pointreading, it is good practice to install two-way vent valves in both portsof a differential pressure gage. These valves permit closing off thesensing lines in an operating system while simultaneously ventingboth ports of the gage to the atmosphere to permit checking the zerosetting or re-zeroing as necessary. Your nearest Dwyer field sales engineer will be glad to review yourapplication with you. He/she may help ensure maximum performanceof the Dwyer control or gage specified.

Additional Design Precautions continued on next page

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helpful information

Absolute Pressure (psia) – The total force per unit area exerted by afluid. The sum of atmospheric and gage pressures.Alternating Current (AC) – Current that reverses polarity at a uniformfrequency.Atmospheric Pressure – The force exerted per unit area by the weightof the atmosphere.Cavitation – Process in which small bubbles are formed and implodeviolently. Contacts – Elements used to mechanically make or break an electriccircuit.Cv or Valve Flow Coefficient – The number of US gallons per minuteof water at 60°F that will pass through the valve with a pressure dropof 1 psi. Direct Current (DC) – A current with a constant polarity.Double Pole Double Throw (DPDT) Switch – Two separate switchesthat operate simultaneously, each with a normally open and a normal-ly closed contact and a common connection. Gage Pressure (psig) – The measure of force per area exerted by afluid using atmospheric pressure as the zero reference.Humidity – The amount of moisture in the air.Impedance – The opposition in an electric circuit to the flow of analternating current consisting of inductive reactance, ohmic resistanceand capacitive reactance.Maximum Surge Pressure – Safe pressure for the switch housing butwhich may damage the mechanism by continuous or repetitive applica-tion.Normally Closed Switch – A switch in which the contacts are normal-ly closed. Actuation opens the contact.Normally Open Switch – A switch in which the contacts are normallyopen. Actuation closes the contacts.NPT – National Pipe Thread.Null Switch – A floating contact switch with a zone of no contact.Often used to operate reversible motors.

Glossary of Terms

pH – An indication of the acidity or alkalinity of a solution in unitsranging from 0 (most acidic), to 7 (neutral), to 14 (most alkaline).Pressure Drop – The difference in upstream and downstream pres-sure of the fluid flowing through a valve.Range – The span of differential pressures or flow rates withinwhich the sensing element of a given switch can be set to actuate anelectric switch.Rated Pressure – The maximum pressure that the actuating compo-nents of the switch in contact with the media can withstand contin-uously and/or repeatedly without risk of permanent damage.Relative Humidity – The ratio of the quantity of water vapor in theair to the quantity of water vapor required for saturation at the sametemperature.Repetitive Accuracy – The ability of a pressure or flow switch tooperate repetitively at its set point under consistent conditions.Saturation Point – The point at which condensation is formed.Serial Transmission – Sending one bit at a time on a single trans-mission line.Set or Actuation Point – The exact air pressure or flow rate whichwill cause the electric switch to actuate.Single Pole Double Throw (SPDT) Switch – A switch combiningboth normally open and normally closed switch contacts.Solid State – Any element that controls current without movingparts, vacuum gaps or heated filaments.Temperature Compensation – The correction for the influence oftemperature on a measurement.Transducer – Any device that generates an electrical signal fromphysical measurements.Transmitter – A device that translates the low-level output of a sen-sor or transducer to a higher level signal suitable for transmissionto a site where it can be further processed.Viscosity – The resistance of a fluid to flow when subjected to shearstress.

For steam service of 35 psig or higher, or high temperature media, asiphon or remote connection is recommended to ensure that the ambienttemperature rating of the switch is not exceeded. When applying a Mercoid Bourdon tube pressure switch with flammable,hazardous or toxic gases or liquids, a stainless steel Bourdon tube controlshould be specified as the welded Bourdon tube will reduce chances ofleakage in case of fire. For applications with any chloride media, the use ofa 316SS Bourdon tube pressure switch is also recommended. For addi-tional protection, a diaphragm seal can be specified to prevent corrosive,viscous or other damaging media from entering the Bourdon tube in thecontrol. An over pressure diaphragm should be specified where the normal systemworking pressure is low but pressure may occasionally rise above therange of the control to as high as 5000 psig. The over pressure seal isdesigned to protect the control if pressure increases beyond a predeter-mined point. When a set range is exceeded, the diaphragm seats and nofurther motion is allowed, effectively limiting transmitted pressure. As with all instrumentation, care should be taken to avoid freezing of themedia in the pressure element to prevent operating failure and damage tothe control.

Additional Design Precautions for Mercoid Products, continued

In applying bulb and capillary temperature controls, specifying a pro-tective well for the bulb may be advisable. The well will permit removalof the control from the system without the problem of escaping mediaor the need to shut down the system. In addition, the well may providerequired media compatibility. However, protective wells do increase theresponse time of the temperature control, a factor to be considered intheir specification. Level controls with cast iron housings should not be specified for usewith flammable, explosive or toxic media. In the intense heat of a fire,cast iron housings can crack and release the media. Where a liquid level control must function reliably under conditions ofextreme vibration, a special anti-vibration mechanism is available andshould be specified.

Specifying engineers should obtain a free copy of the MercoidCatalog, Bulletin E-60-M, a technical guide to the selection andapplication of Mercoid DA Series temperature and pressure con-trols.Finally, consult the factory or Dwyer field sales engineer if you haveany questions regarding the application of Mercoid products.

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All Dwyer dial-type differential pressure gages employ theMagnehelic magnetic linkage principle to measure differential pres-sures from 0.25˝ Water Column (w.c.) to 30 psig in total pressureenvironments up to 500 psig. This family of gages provides a directindication of differential pressure on easy-to-read 4˝ dials(Magnehelic®, Capsuhelic®, Photohelic®, and Capsu-Photohelic®

gages) and 2-1/2˝ dials (Minihelic®, Mini-Photohelic® gages) utiliz-ing a reliable, shockproof, diaphragm actuated mechanism that pro-vides a low-cost gage with high performance. While primarilyapplied in the measurement of low differential pressure in air andgases, Dwyer Capsuhelic® differential pressure gages are suitablefor use with compatible liquids. Standard Capsuhelic® differentialpressure gages and Capsu-Photohelic® switch/gages have alu-minum bodies; brass bodies are available and are required for waterservice. New Mini-Photohelic® differential pressure switch/gagecombines the time proven Minihelic® II differential pressure gagewith two SPDT switching setpoints.The Dwyer Photohelic® and Capsu-Photohelic® series of differentialpressure switch/gages add phototransistor actuated relays witheasily adjusted set points to provide low and high limit electricalcontrol in addition to the measurement of differential pressure. Allof these gages are commonly employed to measure and controlpressure, velocity, or flow in stacks, air conditioning systems andclean rooms, to monitor furnace draft, to indicate pressure dropsacross orifice plates or venturi tubes, and to measure liquid levelswith bubbler systems, fume hood exhaust velocities, blood or res-piratory pressure in medical equipment, cooling air pressure inelectronic equipment enclosures, etc.

Differential Pressure Gages and Switch/Gages

Magnehelic® differentialpressure gage

Capsuhelic® differentialpressure gage

Photohelic® pressureswitch/gage

Capsu-Photohelic®

pressure switch/gage

Minihelic® II differentialpressure gage

Model 424 Durablock®

Inclined-Vertical

Series 1223 Flex-Tube® U-tube

Mark II

Model 1211 Slack-Tube®

roll-up

Series 7100Spirahelic® gage

Series7000BSpirahelic®

gage

Mini-Photohelic differential pressure switch/gage

Series 475Mark III

handhelddigital

manometer

Series 490 wet/wethandheld digital

manometer

Dwyer manufactures a wide variety of virtually unbreakable plasticmanometers. Both portable and stationary manometers of the U-tube,well-type, inclined and inclined-vertical types provide for the measurementof low range air pressures, pressure differentials and vacuum. Severalmodels of Flex-Tube®, U-tube and Slack-Tube® (roll-up) manometers pro-vide high accuracy at low cost for field work. Mark II molded styrene-acry-lonitrile plastic models serve minimum-cost industrial applications.Durablock® solid acrylic machined manometers function as standard refer-ences in the laboratory and for field work as well. New handheld digitalmanometers offer convenience and accuracy in compact, portable units.

Manometers

Dwyer Spirahelic® gages incorporate spirally and/or helically woundBourdon tubes. All feature solid-front design with a simple, reliable directdrive mechanism. Models are available in ranges from 0-30 to 0-10,000psig and metric equivalents in kPa, MPa and Bar. Units are available inboth turret and panel mounts, digital displays, NEMA 4X housing, andaccuracies up to ±0.25% of full scale, ASME Grade A, 2A & 3A. Special Test Gages feature a precision knife edge pointer, finer minor divi-sions and a mirrored band to prevent parallax error. For digital indication, the Series DPG offers exceptional accuracy (±0.25%of full scale) in a NEMA 4X housing. The DPG is battery-powered, has a 4-digit display to reduce reading errors, and is an economical replacementfor outdated analog gages. Other pressure gages available include the Series 62000 and 64000. TheSeries 62000 is an extremely versatile, low cost gage that offers a dualscale in psi and kPa, with ranges up to 300 psig (2100 kPa) and selectableback or bottom mounting positions. The Series 64000 stainless steel pres-sure gage is ideal for applications involving pressure spikes, vibrations andpulsations, and delivers accurate readings in the harshest environments.

Pressure Gages

Series DPG digital

pressuregage

products from Dwyer

Series62000

PressureGage

Series64000

StainlessSteel

PressureGage

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Dwyer offers a wide range of differential pressure switches, includingexplosion-proof models, which are precision diaphragm operated andwhich can be actuated by positive, negative or differential pressures.Designed for low and very low pressure differential, ranges from .03˝w.c. to 200 psid are available. These switches are most commonlyused to control or prove air flow in air conditioning, refrigeration, ven-tilating and combustion systems. The W.E. Anderson® Model H3Explosion-proof differential pressure switch serves process applica-tions requiring higher ranges and operating pressures and/or aggres-sive gas or liquid media. Series MDA & MDS miniature pressureswitches are perfect for low pressure control. The MDS has a doublediaphragm design to protect against false actuation due to shock orvibration, and the MDA has a field adjustable setpoint.

Model 1638

Model H3 Model H-2Duotect®

pressureswitch

Model V4-2-UFlotect®

flowswitch

Model V-6Flotect®

flow switch

Model 1950explosion-proof

Series MDAPressureSwitch

Model 1910 Model 1823

The Dwyer 605 Differential Pressure Transmitter combines state ofthe art sensor technology with the proven design of the Magnehelic®

gage. The transmitter provides a standard 4-20 mA analog signal out-put in ranges as low as 0.1˝ w.c. to 200 psid and 0-3˝ w.c. to 0-100psid for the Series 616C transmitter and is accurate within ±2% innormal ambient temperatures. The Series 616C features exceptional±1% accuracy. Applications include controlling of variable-speedfans, blowers and positioning of system dampers. Supplies data onair velocities in ducts and pressure drops across air filters. In themedical field it can interface with a computer to provide blood andrespiratory pressure data.Series 607 is ideal for reliability in critical applications where 0.25%accuracy is required. It is designed to resist shock and vibrationwhile maintaining an accuracy of ±0.5%. The Series 645 is designedespecially for liquid and air applications and has an amazing accura-cy of ±0.25%. It is available in bi-directional ranges and optional 3valve manifold.

Series616C

transmitter

Series 604AtransmitterSeries 605

Indicating transmitter

Mercoid® DASeries

pressureswitch

Mercoid®

1000 Seriespressureswitch

The Mercoid® Division of Dwyer Instruments, Inc. manufactures abroad line of Bourdon tube and diaphragm operated pressure switch-es, most models offering either mercury or snap action electricalswitches and adjustable deadbands. Ranges to 8000 psig are availablewith explosion-proof or weatherproof options. The Mercoid DA Serieswith optional mercury switches are well-known for their long term reli-ability and resistance to contact corrosion. They are ideal for both highand very low direct current applications. For use in liquid and gasapplications.W.E. Anderson® manufactures the unique dual pressure Duotect®

explosion-proof pressure switch with one diaphragm actuating twosnap switches. The switches operate independently of each other andcan be adjusted to settings of up to 1500 psig.Series A1PS/A1VS are economical pressure switches that provide fieldadjustable control and are available in vacuum, pressure or compoundranges. The Series APS/AVS provides reliable switching forpressure/vacuum alarms.

Differential Pressure Switches

Differential Pressure Transmitters

Pressure Switches

Flow SwitchesModel V10Flotect®

mini-sizeflow switch

The W.E. Anderson® Division of DwyerInstruments, Inc. provides a line ofFlotect® vane operated flow switchesfor installation in pipelines or ducts toprotect equipment against excessflow, low flow, or stoppage of liquids,gases, or slurries.Explosion-proof construction is stan-dard for most of these switches. They

products from Dwyer

Series MDSPressureSwitch

Series 607transmitter Series 645

Wet/Wet differentialtransmitter

SeriesAPS/AVSadjustable pressureswitch

SeriesA1PS/A1VS

pressureswitch

SeriesP5shuttleflowswitch

can be installed in pipes with diameters from1/2˝ up to 20˝ or more. Other models such as the Model V10 are idealfor compact, cost effective requirements. TheP5 PVC shuttle flow switch is designed withone moving part for long life and minimummaintenance.

Model 300sight flowindicator

Model 360Fflanged

sight flowindicator

For liquid flow, the W.E. Anderson®

Division manufactures a broad line ofspinner, flapper, rotor and see-through sight flow indicators for pipesizes from 1/4˝ to 4˝ in bronze, stain-less steel and polysulfone housings.Dwyer Series GFC gas mass flowcontroller is a versatile solution toapplications where strict flow meter-ing and controlling are imperative.Field selectable 0-5V or 4-20mA lin-ear output is standard.

Series SFI 800 sight flowindicator/

transmitter

Sight Flow Indicators &Transmitters

Series GFCgas mass flow

controllers/meters

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products from Dwyer

Series L10Flotect® mini-size

level switch

Series F7 levelswitches-vertical

Series L8 Flotect®

liquid level switch

The Mercoid® DA-7035 Series bulb and capil-lary type temperature switches utilize the sameBourdon tube switching mechanism as the DASeries pressure switch. Temperature ranges to530°F are available. The Series M51 isdesigned for use as a limit or alarm switch oras a fan control on furnaces, ovens, dryers,etc. with ranges to 650°F. The low-cost SeriesTS digital temperature switch is a state-of-the-art control used in heating and refrigerationsystems.

Series DA-7035temperature switch

Series M-51bimetal

temperature switch

Below, left to right: Rate-Master®

Models RMC, RMB, & RMA

Right:Series UV

Ultra-ViewTM

polysulfoneflowmeter

Dwyer flowmeters are used in a multitude of applications in industrial,commercial, scientific and medical equipment where the flow of air,water, oil, or compatible gases or chemicals must be monitored orcontrolled. Dwyer offers a multitude of variable area flowmeters forthese applications. Three sizes are offered in the extremely popularRate-Master® series. Manufactured from durable molded polycarbon-ate, choose from the many available ranges in air (0.1 to 1800 SCFH)or water (1 GPH to 8 GPM). Dwyer’s Visi-Float® flowmeter series,manufactured from machined acrylic, are available in three body sizesand many ranges – 0.1 SCFH to 100 SCFM of air and 0.6 GPH to 20GPM of water. The latest edition to Dwyer’s variable area flow meterfamily is the Series UV Ultra-View™. Highly engineered, the Series UVflow meter is made of Polysulfone and does not contain any metal wet-ted parts, making the Series UV perfect for applications involving ultra-pure water. Units are extremely accurate and can withstand 100 PSI(10.3 bar) pressure at 212°F (100°C). Dwyer’s VA glass flowmetersoffer superb precision and control. Materials of construction and uni-versal scales offer the ideal flexibility when measuring different gasesand liquids. The Series DR direct reading flowmeters give users theoverall advantage of glass flowmeters while displaying flow rates on adirect read scale.

Flowmeters

Model 400-10air velocity meter

Model VT-200vane thermo-anemometer

Dwyer differential pressure gages and manometers are offered individ-ually and as complete air velocity measuring instrument kits. Suppliedwith gage, Pitot tubes and connecting tubing, this group includes awide variety of types and price ranges from exacting laboratory needsas well as plant or field use. These gages are calibrated to read airvelocity directly in feet per minute as well as static and velocity pres-sure in inches of water column. Pitot tubes are offered in numerousmodels. The Series 641 Air Velocity Transmitter delivers precise read-ings in ranges to 15,000 FPM or 75 MPS and has an optional LED read-out. The VT-200 vane thermo-anemometer is the ideal instrument forHVAC applications, measuring air volume, air velocity and temperatureand storing up to 1000 measurements with built-in datalogging capa-bilities.

Dial type Magnehelic®

air filter gage

Model 250.5 Durablock®

inclined manometer

The Magnehelic® dial-type differential pressure gages and themanometers described above are also offered as complete air filtergage kits to measure resistance of air flow to indicate whether a filteris clean or dirty. The kits are provided complete and ready to install,including static pressure pick up tips and connecting tubing. TheCapsuhelic® gage is suitable for measuring differential pressure acrossmany liquid filters.

Mark IIInclined-vertical

Air Filter Gages

Air Velocity Instruments

Series 475-1T-FM-AV airvelocity kit

Model 471-3 digital thermo-anemometer

Temperature Switches

Series TS digitaltemperature

switch

Anderson Model L-4 level switch

Level controls from the Mercoid® Division cover abroad range of applications in the process, refin-ing and utility industries. Chamber type level con-trols are available with operating pressure ratingsto 2300 psig. The Series 190 displacer type con-trol features adjustable level setpoints and is idealfor industrial sumps. Other models available forboiler water level control. Most Mercoid® levelcontrols are available with either mercury or snapaction switches. Explosion-proof float switcheswith wetted parts of brass or stainless steel areavailable from W.E. Anderson® Division to moni-tor liquid levels in tanks. Explosion-proof floatswitches with wetted parts of brass or stainlesssteel are available from W.E. Anderson® Divisionto monitor liquid levels in tanks. The L-8 LevelSwitch features a leak proof body and optionalweatherproof enclosure; Series L10 Level Switchinstalls easily in-wall or externally and accommo-dates liquids with low specific gravities.

Level Controls

Model OLS-12 optical

level switch

Below, left to right: Visi-Float®

Models VFCII, VFB, &VFA

Below, left to right:Series DR direct read-ing glass flowmeter;Series VA Teflon®/

glass flowmeter

MercoidSeries190displacertype levelcontrol

pg 7 12/11/03 11:15 AM Page 1

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products from Dwyer

Temperature/Process Controls and Sensors

The Love Controls Division manufactures a wide variety of tempera-ture/process controllers for the packaging and molding industries.These controllers are available in 1/4, 1/8, 1/16 and 1/32 DIN sizes.Selectable control ON-OFF, P, PI or manual PID, or automatic SELF-TUNE® PID control is available. Series TST dual probe digital tempera-ture switches are economically packaged with three SPST relays forrefrigeration and defrosting applications.

W.E. Anderson® pneumatic control valves are used in temperature con-trol applications to protect sensitive equipment from overheating. Sizesavailable are 1/2˝ to 2˝ in bronze or 316 stainless steel material.Butterfly valves are also available from W.E. Anderson® in sizes 2˝ to16˝ to meet your difficult application. 3-way butterfly valves with actu-ator are used to control the flow of water accurately in a water-sideeconomizer system. Series ABV automated two-piece brass ball valvesincorporate a full port brass ball valve for great flow rates with minimalpressure drop. Proximity® Controls Division manufactures position indi-cating switches that can mount on the Hi-Flow® valves and Plast-A-Vane®

butterfly valves to give visual indication of and switch output of the valveposition.

2500 16S32DZ

Valves and Position Indicating Switches

Position indicating

switch

Self-actingtemperaturecontrol valve

3-way butterfly

valve withactuator

Hi-Flow™

valve

Series ABV auto-mated two-piecebrass ball valve

No. 1200-BCombustion Test Kit

Combustion Testing Instruments

are also available separately, in various ranges for use in testingatmospheres on board ships and submarines, in greenhouses and inCO2 blanketed flammable liquid tanks and compartments. The Dwyer450 CO monitor is ideal for quickly monitoring carbon monoxide inambient air and for detection of Carbon Monoxide in residential/com-mercial heating systems. Alarms may be set to give an audible indica-tion of reaching a threshold.

Individual Dwyer instruments measurefurnace draft, the CO2 content of fluegases, stack temperature, and smoke den-sity. Usually supplied as a complete,portable kit for combustion efficiency test-ing, these instruments serve to adjust gas,oil, or coal fired furnaces and boilers formaximum combustion efficiency.The Dwyer CO2 indicators and monitors

New Products from Dwyer Instruments, Inc.

Minihelic® II differential

pressure gage

Mini-Photohelic differential pressure

switch/gage

Series DPG digital pressure gage

Series 616Ctransmitter

Series VRView-Rite

LevelIndicator

Series P4Ryton® PistonFlow Switch

Series UVUltra-ViewTM

polysulfoneflowmeter

Series SFI 800 sight flow indicator/

transmitter

Series TS digitaltemperature

switch

Series450 COMonitor

Series DCT dust collector timer controller

Series 641 air velocity transmitter

Series PBLT (left) &SBLT submersiblelevel transmitters

Series PLSpaddle level

switch

Series450 COMonitor

Series MPCpump controller

16S

Series 490 wet/wethandheld digital

manometer

TST

pg 8 12/11/03 11:24 AM Page 1

Checking the gas pressure to a heating unit on the burner sideof the regulator is a standard installation and service routine.The Dwyer Series 475 Handheld Digital Manometer is a low-cost, durable device that is easily transportable in a pocket orbriefcase. Units are highly accurate with 0.5% full scale accura-cy. Some servicemen prefer our portable Dwyer Magnehelic®

differential pressure gage with dial type scale for field use.

Main Valve

Gas

Pilot Gas

Regulat or

Main Burner

ControlValve

Series 475

Pressure Tap

Alarm Lamps

Photohelic®

Switch/Gage

To Dialysis Machine

Power Cord

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Air FlowStatic Pressure Sensor

B

A

Magnehelic® Gage

Durablock® Inclined Manometer

Duct

The amount of draft over the burner fire in oil, gas, or coal firedresidential, commercial, or industrial furnaces and boilers is animportant factor in combustion efficiency. A Dwyer Durablock®

portable inclined manometer (when used in this application, itis commonly called a “draft gage”) provides an easy, accuratemeasurement of the negative pressure over the fire or in theflue. A Magnehelic® differential pressure gage can also be usedto make such a measurement. It offers advantages if continu-ous monitoring requires a permanent installation; it is easy toread, has no fluid to evaporate, and costs less. To optimize fur-nace combustion efficiency, use a Dwyer Model 1200 combus-tion test kit which tests for draft, CO2, smoke density and stacktemperature.

Durablock® Inclined Manometer

Burner

FurnaceFlue

ProbeThroughInspectionDoor

pressure

Static pressure relative to atmosphere down to less than .01” wccan be measured directly using a Dwyer Magnehelic® differentialpressure gage or any Dwyer manometer, inclined or vertical. If amanometer is used, an inclined type may be preferred to provideadequate resolution, particularly at very low pressures.A static pressure sensor installed in the duct or plenum and con-nected to the high or low pressure port of the gage, as appropri-ate, does the job. While a static pressure sensor, or tip (A in theillustration) is recommended to reduce the effects of the turbu-lence, a flanged connection to a hole free of burrs in the wall ofthe duct (B) is also satisfactory for static pressure measure-ments when static pressure is relatively high and velocity rela-tively low.

This application for the Dwyer Photohelic® differential pressureswitch/gage utilizes a standard unit as a self-contained arterialblood pressure monitor to be used with any kidney dialysisequipment. The gage is connected to drip chamber in the arte-rial blood line and monitors the pressure in the chamber.Instead of inches of water column, the gage is calibrated in mil-limeters of mercury. When blood pressure falls below orexceeds preset limits, a buzzer sounds and a “high” or “low”lamp lights which, for maximum patient safety, must be resetmanually when pressure is again within the preset limits.

Measuring static pressure in an air duct or plenum.

Digital Manometers used to check gas pressure to a heating burner.

This portable monitor uses a Photohelic®

switch/gage to show pressure and actuate hi-loalarm signals during kidney dialysis.

Using a draft gage to adjust for efficient combustion.

pg 9 12/10/03 6:32 PM Page 1

The Dwyer Magnehelic® or Minihelic® differential pressuregages provide convenient visual indication of HVAC system firedamper position. Mounted in access doors (or another conven-ient location) with the high pressure port sensing upstream stat-ic duct pressure, the gage will read upscale should the damperclose due to some failure. During system operational checks,each damper reaction can be easily monitored. This applicationeliminates difficult and time-consuming visual inspections - andencourages more frequent inspections for proper operation. Ifthe rear of the gage will be exposed to dust-laden ambient air, afilter plug should be placed in the pressure port and vented tothe atmosphere to prevent dust from accumulating in the gageover a long period of time.

OPEN CLOSED

Air Flow

Damper

Duct

Magnehelic®

Gage

HI

Air Supply

Magnehelic®

GagesHI

LO 2

1

B

A

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Magnehelic® Gage

CleanGas

Drain

Drop Legs

HI LO

Dirty Gas

Water Supply

Nozzles

Venturi Slot

When air or other gas must be pumped through a processor,measuring the differential pressure across the blower with aMagnehelic® differential pressure gage will monitor the flowrate as a function of blower static pressure to indicate properoperation. As an alternative, a Dwyer Photohelic® switch/gagecan be used where deviations from normal flow due to filterloading, other restrictions in the system or blower failurerequire automatic shutdown of the system. Either a Minihelic®

differential pressure gage or a Mark II manometer will serve ifa lower cost gage is desired. If no visual gage is required, aDwyer differential pressure switch will provide the automaticshutdown or alarm function.

Filter

Air/Gas Out

HI

LOMagnehelic® Gage

Air/Gas In

ProcessororConditioner

Blower

pressure

This scrubber designremoves unwanted dustor particulate matterfrom air or gas using anadjustable throat venturi.To adjust the pressuredrop across the venturi, a jack-screw-actuatedsliding vane varies theslot width. A permanentlymounted DwyerMagnehelic® differentialpressure gage indicates

A zero-center Dwyer Magnehelic® differential pressure gagewith an 0.25˝ wc range either side of zero makes an effectivemonitor for proper operation of room pressurization systems.In the example, differential gage B has its high pressure portopen to room 2 and its low pressure port to room 1; gage Ahas its high pressure port open to room 1 and its low pressureport open to the atmosphere. With the makeup air supplydamper adjusted properly, room 2 will be a higher pressurethan room 1 which is at higher than atmospheric pressure; bothgages will read positive. Should the air supply to room 2 beobstructed, gage B will read negative. If the air supply failsentirely, both gages will read zero. For even better security, aPhotohelic® switch/gage will provide automatic alarm or start-up of a backup system.

Differential pressuregage assists operator in adjusting venturipressure drop in dust scrubber.

Gage indicates fire damper position in heating/AC duct.

Dwyer gages indicate pressurization of special rooms. A choice of several Dwyer products will monitor or

protect this processor.

the venturi pressure drop while the operator adjusts to thedesired or design setting. Where water may possibly enter thegage sensing lines, as in this application, drop legs with drainvalves are needed to permit draining the lines at their lowestpoint. Good engineering practice dictates that the Magnehelic®

gage always be mounted above the sensing tap when possibleto prevent moisture accumulation in the lines and gage. At min-imum, mount the gage above the lowest point in the sensinglines.

pg 10 12/10/03 6:28 PM Page 1

This setup provides a low cost means of checking containers orassemblies for no leakage or an acceptable rate of leakage. Withthe unit under test in place on the seal, the operator opens thevalve to pressurize the system to the test level set by the regu-lator. After the well-type manometer stabilizes, the valve isturned off. Any leakage is reflected as a drop in the manometerreading, the leakage rate being proportional to the rate of dropin the reading. A Dwyer inclined manometer can provide an evenmore sensitive indication if required.

Well-TypeManometer

ContainerUnder Test

Seal

Valve

Shop Air

Regulator

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HI

LO

Magnehelic® GageStack Gas

Flow

SupplyGas

Jet

Sensing Ports

An automobile manufacturer uses an in-house designed systemfor production line testing of fuel systems. The total system isa complex, integrated fluidic circuit that charges the automo-bile’s fuel system through the gas tank fill pipe. One section ofthe system senses leaks due to disconnected lines of faultyconnections by monitoring the differential pressure betweenthe auto fuel system and a reference tank with a Magnehelic®

differential pressure gage after the charged system is sealedoff.

pressure

In a hostile environment or in very low flow situations such asthose encountered in stack gas flow measurements, flow can bemeasured more reliably by a proprietary device called a “fluidicflowmeter”. A jet of compatible supply gas envelopes both sym-metrically placed sensing ports but is displaced in proportion tothe flow of stack gas being measured. This results in a differ-ence in pressure between the ports when flow is other than zero,causing the Dwyer Magnehelic® differential pressure gage toread upscale. Calibration can be direct or in inches of water inconjunction with a calibration curve or table. This device can becleaned remotely by injecting solvent into the system. It alsoprovides a measurement “gain” enabling lower velocity readingsto be taken than is possible with other techniques.

A fast, repetitive check for leakage in various containers, valves,assemblies, etc. can be made with this test setup. During test-ing, the valve is opened after the dry air supply is set to theproper test pressure. As a low range Visi-Float® flowmeter isused to obtain sensitivity, the float will go to the top of the bore.However, as soon as a unit under test is placed in position, thefloat will fall to the zero mark if no leakage exists. The rate ofany leakage will be a function of the flow indication. Dry air isusually necessary to prevent the float from sticking in the boredue to accumulated moisture.

Sensitive gage measures low flow of stack gas.Dwyer well-type or inclined manometers used tocheck for leaks in containers or assemblies.

Another system of leak testing uses a Dwyerflowmeter.

In-house engineers use a Dwyer gage on production line test for integrity of auto fuel systems.

Test Seal orConnection

Flowmeter

ValveRegulatorDryer

ShopAir

Magnehelic® Gage

Hose

ControlPanel

Fill PipeFitting

pg 11 12/10/03 6:35 PM Page 1

Valve

LOHISeries 490Wet/WetHandheldDigital Manometer

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The existence of a static pressure above or below a requiredlevel (compared to atmospheric) is easily determined by con-necting an appropriately installed static pressure tip to theappropriate port of a differential pressure switch, such as aDwyer Series 1600, 1800 or 1900 differential pressure switch-es. When the pressure reaches the preset switch point, the con-tacts are closed to activate a warning lamp or other alarmdevice. It is good practice to mount the differential pressureswitch with the ports down to prevent moisture from enteringthe diaphragm chamber. The diaphragm should be vertical andin the same plane as any vibration or anticipated shock move-ment.

Air Flow

Static Pressure Sensor

Duct

DifferentialPressure Switch Indicator

Lamp

Power Supply

pressure

The Dwyer Series 490 Wet/Wet Handheld Digital Manometer isa portable, industrial instrument designed for processes withliquids or gases. The 490 is often used to measure pressuresin hydronic applications, but with all 316 stainless steel wettedparts it can also be used in systems where aggressive media ispresent.In the above application, the 490 is used to measure the pres-sure differential on a control valve in a multi-story buildingwater system. The user balances the pressure differential onthe control valve to ensure every floor receives approximatelythe same pressure.

Leak testing done with low range differentialpressure gages.

Measure pressure in hydronic applications.A differential pressure switch and warning lampmonitor static pressure.

This setup provides a very sensitive and relatively fast method ofleak detection. With one hand, the operator places the unit to betested on the test seal and, with the other hand or one foot, oper-ates the solenoid valve control button. With the unit under testin place, the normally open solenoid valve permits equal pres-surization of both sides of the Dwyer Magnehelic® differentialpressure gage, with a resulting zero reading. The needle valve isadjusted once to equalize the time it takes to pressurize bothgage chambers and to minimize upscale gage readings duringpressurization. When the solenoid valve is activated (closed) anyleak quickly reduces the pressure on the low side of the gageand an upscale reading results. The availability of very low rangeMagnehelic® gages allows selection of a model which will quick-ly respond to a small leak with a significant reading, even atmodest test pressures. As an alternative, use a Photohelic® dif-ferential pressure switch/gage to provide an alarm or, in auto-matic testing, “kick-out” of the leaky unit.

Shop Air

Regulator

Push button

SolenoidValve

NeedleValve

Test Sealor Connecti

Magnehelic® Gage

HI LO

Inflatable life rafts include small 1 inch diametergages.

Inflatable life rafts used on military and commercial aircraftrequire highly reliable components for obvious reasons. Theinflation systems on some of these rafts include a very smallversion of the Spirahelic® gage to reveal the pressure in thecompressed air bottle so it can be easily checked prior to flight.A Spirahelic® gage in a stainless steel case only one inch indiameter provides the required performance and reliability.

43

InflatableLife Raft

1˝ Dia. Stainless SteelSpirahelic® Gage

pg 12 12/10/03 6:37 PM Page 1

High pressure lines or systems for air, gases, or liquids can bemonitored for proper pressure between desired limits with aDuotect® dual pressure switch. Independent low and high alarmor control points can be set from 5 to 1500 psig. With two indi-vidual switches operating from a common diaphragm, oneDuotect® switch does the job. The high and low pressure indica-tors or alarms are activated only when the limits are exceeded;both are deactivated when the pressure is within the limits. TheDuotect® switch is explosion-proof and can be used with haz-ardous media or in explosive atmospheres.

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During asbestos removal operations, it is essential to monitor andrecord the negative pressure compared to atmosphere which mustbe maintained in the work space to prevent escape of airborneasbestos particles. A Dwyer Series 607 transmitter provides a 4-20mA control loop signal proportional to pressure to a strip chartrecorder with a 4-20 mA input configuration. Thus, a permanentrecord of work space pressure is obtained. To provide an audiblealarm should the pressure go positive for any reason, a DwyerModel 3000-00N SR Photohelic® switch gage is connected in par-allel with the transmitter sensing line and connected electrically toan audible device. The Model 3000-00N-SR features an offset zeropressure point to actually allow below zero indication of pressureplus a single setpoint adjustable from the front of the gage for set-ting the alarm level at or within a few hundredths of an inch ofwater column of zero room pressure.

pressure

This portable pressure monitor alarm utilizes a Dwyer Mini-Photohelic differential pressure switch/gage to monitor eitherpositive pressure, as in a clean room, or negative pressure, asin a fume or paint spray hood. It sounds an alarm, both audibleand visual, when pressure exceeds either a preset high or lowlimit. The unit can be used temporarily to verify proper opera-tion after initial installation. Or it can be mounted permanentlyfor continuous monitoring. In applications where a single fixedalarm pressure level is sufficient, a differential pressure switchcan be used instead.

One diaphragm actuates two independent explosion-proof switches in Duotect® pressure switch to monitor pressure.

Compact switch/gage monitors pressure, actuates alarm.

Transmitter and Photohelic® switch gage monitor negative pressure during asbestosremoval operations.

Blowerand AirFilter

PressurizedClean Room

Fume Hood

Portable Monitorand Alarm Units

Exhaust

Mini-Photohelic

HI

LO

HighPressureIndicator

LowPressureIndicator

Duotect® DualPressure Switch

Pressurized Line

Series 607 Transmitter

HI

LO

SignalLoop

To WorkSpace

Photohelic®

Switch/Gage

HI

LO

AudibleAlarm

The Dwyer Series DPG with oxygen cleaning and 5000 psi rangeis used in gas blending applications for filling scuba diver's airtanks. The DPG is the master mixing gage in this manifoldapparatus. Two or three gases may be blended with the mani-fold to produce the appropriate blend of breathable gas depend-ing on the diver and the depths they will reach. With the flowadjustment knobs and the 0.25% full scale accuracy DPG, pre-cise tank charging rates are maintained.

Series DPG-100Digital Pressure Gage

DivingTanksLarge

Tank

LargeTank

Filling Scuba Diver’s Air Tanks.

pg 13 12/10/03 6:39 PM Page 1

Low cost Dwyer Minitactor® differential pressure switches willsense pressures produced by physically challenged individualsto control electrical devices which render them assistance. Thesoft cushion-bellows can be squeezed by almost any body con-tact and the gooseneck mounted mouthpiece blown into bymouth to activate the Minitactor® switches. The mouthpiece canalso be teed into a third Minitactor® switch on the low pressureside so both blowing and sucking can produce separate controlfunctions. These sensors are both very sensitive and safe as theelectrical circuits are isolated from the individual by the rubbertubing.

Blower or Compressor

Plenum or

Tank

HI

HI

HI

Duct or Pipe

Duotect®

PressureSwitch

(High PressureApplications)

LowLimitSwitch

HighLimitSwitch

ControlUnit

Photohelic®

Switch/Gage(Low PressureApplications) Differential

PressureSwitches(Low PressureApplications)

Bellows

ConnectingCable to Control Unit

Enclosure

Mouth Tube

Minitactor®

Switches

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A controlled inert atmosphere “glove-box” is used in the fieldsof physical chemistry and metallurgy for handling and weldingspecial or hazardous materials. A Dwyer Photohelic® differentialpressure switch/gage serves as an automatic and readilyadjustable pressure control for the helium, argon or nitrogengas used in the system. The box is first evacuated, then pres-surized with the required gas. Therefore, a zero-centerPhotohelic® switch/gage is used, permitting both pressure andvacuum to be read and controlled by a single gage. Use of thelow pressure gage connection (rear chamber of gage) and aBuna-N diaphragm is suggested to minimize leaks from or tothe atmosphere.

pressure

Air pressure can be controlled in a system by using a DwyerPhotohelic® differential pressure switch/gage, one or twoDwyer differential pressure switches, or a W.E. AndersonDuotect® pressure switch, depending on the range of controland/or levels of pressure involved. All of these switches moni-tor the pressure in the system and will cause the pressuresource - a blower, compressor or pump - maintain the systempressure within the preset high and low levels. For systemsusing low pressures (.01˝ wc to 10 psig), the Photohelic®

switch/gage or Dwyer pressure switches are the best choice.For higher system pressures (5 to 1500 psig), we recommendthe Duotect® pressure switch. When you install differentialpressure switches on air systems, it is best to mount the switchwith ports down to prevent moisture from entering thediaphragm chamber - and with diaphragm vertical and in thesame plane as any vibration or anticipated shock movement.

Switch senses air pressure changes in textileequipment. Physically challenged individuals control equip-

ment with Dwyer switches.

Controlling pressures in air or gas systems.

Zero-center switch/gage controls the inert atmos-phere in glove box.

In the textile industry, a Dwyer differential pressure switch isused to determine when cotton is passing through a battery con-denser. It is used with a control unit to stop a water pump andturn down a burner when no cotton is being ginned. The switchworks by sensing the difference in air pressure between the twosides of the condenser screen. When no cotton is on the screen,the pressure difference will be almost zero. When a batt of cot-ton is being condensed, the air pressure inside the screen will belower than the air pressure in the lint flue. the switch senses thisdifference and closes an electrical contact. Filters are recom-mended at the tap end on the sensing lines in this type of appli-cation, as particulates can clog the sensing lines or accumulatein the switch.

Fan

BatteryCondenser

Lint Slide

Lint Flue

DifferentialPressureSwitch

HILO

GloveBox

LO

SolenoidValve

PressureReliefValve

Regulator

Gas Supply

Vent to Atomospherein Safe Area

Photohelic®

Switch Gage

pg 14 12/10/03 6:40 PM Page 1

To control pressure in air-inflated buildings, the high pressureport of a Dwyer Photohelic® differential pressure switch/gage isconnected to a tap in the building wall. The unit senses over-pressure that may over-inflate the building - or loss of pressurethat may result in collapse - and controls the blower to maintaincorrect pressure. The gage is easily reset to conserve power orprovide extra pressure to resist strong winds. Although two reg-ular pressure switches plus a latching relay may also control theblower automatically at lower cost, the Photohelic® switch/gageis preferred, as it permits both visual reading of inflation pres-sure and easy adjustment of set points to meet varying condi-tions.

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DifferentialPressureSwitch

Tarpaulin OverGrain Pile

Retaining Wall

WindspeedPickup

Control Unit

Blowers

Variable-speed blower drives are gaining popularity as a veryenergy-efficient method of controlling air flow. In a typical sys-tem, a Dwyer Photohelic® differential pressure switch/gagemonitors the static or velocity pressure in the duct downstreamfrom the blower and, within the preset high and low pressurelimits of the null band, the switch/gage controls blower drivespeed to maintain the desired pressure. To meet changing con-ditions, the manual knobs on the Photohelic® switch/gage per-mit easy resetting of control limits.

pressure

Grain piled out of doors must be protected from the weather bya tarpaulin cover. To hold the tarpaulin in place during periods ofhigh wind, this system utilizes a row of exhaust blowers mount-ed through one retaining wall to create a negative pressureunder the cover. The blower control unit uses a Dwyer WindSpeed Indicator pick-up to sense velocity pressure and activatea Dwyer differential pressure switch at a pre-determined windvelocity. Therefore, the fans are turned on only when necessaryto conserve electrical energy. A Photohelic® switch/gage couldalso be used to provide readout of velocity pressure and visualindication of the blower activation setpoint as well as easy fieldadjustment of the setpoint to meet varying conditions.

Fire pump controls operate pumps, supplying water to buildingfire sprinkler systems. These controls turn on the main pumpswhen system pressure falls due to sprinkler heads being acti-vated. Fire pump controls also turn on smaller make-up pumpsto maintain system pressure, which may fluctuate due to smallleaks. These controls almost always employ the Mercoid® DASeries pressure switch due to its rugged design and high relia-bility over long periods of infrequent operation. The DA Seriesswitch provides independent high and low setpoints over theentire pressure range of the switch to meet varying require-ments from system to system. The low setpoint maintains min-imum pressure required for proper system operation while thehigh setpoint prevents damage due to over-pressurization ofthe system.

Dwyer Wind Speed Indicator and differential pressure switch control fans to hold down grainpile cover.

Switch/gage regulates pressure in air-inflatedbuildings.

The Mercoid® DA Series is the industry standardpressure switch for fire pump controls.

Switch/gage controls blower speed to save energy.

Power ToPump

To SprinklerSystem Main

Mercoid®

DA SeriesPressureSwitch

HI

BlowerPhotohelic®

Switch/Gage

Air Out

Blower

Air In

VariableSpeedDrive

HIPhotohelic®

Switch/Gage

pg 15 12/10/03 6:42 PM Page 1

Demand for compressed gas varies in this gas line. So aMercoid® Series DA adjustable deadband pressure switch isincluded to turn the compressor on at low pressure and offwhen the maximum pressure is reached.

Air Inlet Shutters

Drive UnitExhaust Fans

Photohelic® Switch/Gage

ControlUnit

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The high cost of home heating fuels has produced demand formore efficient furnace designs. One such furnace includes anadditional stainless steel cell through which flue gases are rout-ed to extract heat otherwise lost up the flue. The relatively coolflue gas then requires power venting by means of an induceddraft fan. A Dwyer differential pressure switch is built in toprove adequate draft by sensing the negative draft pressurecompared to atmosphere. If the fan or pressure switch shouldfail, the burners are shut off automatically.

pressure

Controlled environment farm buildings are home to a variety oflivestock and temperature and ventilation are as important totheir well-being and growth as proper food and waste removal.The Dwyer Photohelic® differential pressure switch/gage,mounted in a control panel, will sense inside static pressurecompared to outside atmospheric conditions and adjust thepower operated shutters on the fresh air inlets. This maintainsthe required negative pressure in the building to ensure properventilation. Temperature sensors also provide input to controlfan speed as necessary depending on outdoor conditions.

Fuel savings result from switch/gage draft con-trol.

Mercoid® Series DA pressure switch maintainsdesired gas pressure in tank.

Power operated shutters on barn controlled byPhotohelic® pressure switch/gage.

Furnace protected from inadequate draft by fail-safe differential pressure switch.

Automatic vent dampers conserve energy in residential furnacesby closing completely when burner is off to prevent wastefulheat loss up the flue. However, in some industrial heating appli-cations like this asphalt plant dryer, burners run continuously. Tosave energy, another form of automatic damper control main-tains a constant exhaust draft at the point required for most effi-cient operation. In this application, a Dwyer Photohelic® differ-ential pressure switch/gage monitors the negative static pres-sure in the dryer and maintains the desired draft by signaling thedamper actuator to change the damper position when the upperor lower limit is reached. Cost savings can be substantial in highfuel usage systems of this type.

LO

ExhaustDamper

Dryer

Wet MaterialInput

Hot AirInlet

Dry MaterialDischarge

Photohelic® Switch/Gage

Mercoid® Series DAPressure Switch

Receiver

PressurizedGas Out

Compressor

GasSupply

OverpressureRelief Valve

Flue

PowerVentFan

Flue Gas HeatExtractor

DifferentialPressureSwitch

Burners

pg 16 12/10/03 6:43 PM Page 1

The vast number of semiconductor devices manufactured forhigh reliability applications in computer systems, particularlymemory devices, requires weeding out those that will fail early.They are subjected to a burn-in process, i.e., power is applied tothe device to “exercise” it in a high ambient temperature. Fansmove air over a bank of heating elements and then over thedevices being processed. Failure of these fans can damage theburn-in equipment as well as delay completion of the testing ofthousands of devices. A Dwyer 1900 Series differential pressureswitch is installed to monitor air flow and signal an alarm imme-diately upon cessation of proper flow.

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DifferentialPressureSwitch

LO

Drop Leg

Flue GasFlow

Stack

Fan

pressure

In this boiler installation, a differential pressure switch signalswhen the natural draft in the smokestack is insufficient, andalerts the operator for corrective action. The low pressure portof the switch is connected to a tap at the base of the smokestackand the high pressure port is left vented to atmosphere. Thesame set-up can also be used to monitor operation of forceddrafts and shut off firing if a fan fails. In addition to this switch-ing function, a Dwyer Photohelic® differential pressureswitch/gage will also provide a visual indication when required.Be sure to consider compatibility of the pressure switch compo-nents with the flue gases in applications of this type. In flue gasapplication, it is wise to provide condensate drop legs and drainvalves in the sensing line.

Manholes providing access to various underground utility sys-tems must be ventilated with fresh air for worker safety. In coldweather, heating the ventilation air also provides worker com-fort. This small gas-fired heater can be inserted between theventilation fan and hose. A Dwyer differential pressure switch isused to sense air flow through the heater as a function of stat-ic pressure. It will shut down the gas burner if the static pres-sure falls below a level indicating insufficient air flow due to fanfailure or an obstructed air intake.

Safety is increasedwhen draft in thesmokestack is monitored.

Differential pressure switch protects products ontest.

Utility manhole ventilation air heater protected byDwyer differential pressure switch.

Manhole

VentilationHose

Gas FiredHeater Fan

Dwyer Model 1823DifferentialPressure Switch

Data Recorder

ComponentOven Doors

Power SuppliesDifferential Pressure Switch

The 7112B Spirahelic® gage with direct drive triple woundBourdon tube and ASME Grade 2A accuracy is often used onprocess lines to monitor pressures. Ranges from 30 PSIG upto 10,000 PSIG are available along with several compoundranges for systems that experience pressures below zero. Thetriple wound Bourdon tube technology allows the Spirahelic®

Gage to withstand vibration, pulsation and shocks withoutdamage or the need for recalibration.

Process gage monitors line pressure.

Series 7112B Spirahelic®

Direct Drive Pressure Gages

pg 17 12/10/03 6:44 PM Page 1

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pressure

Large, high-volume web printing presses move paper throughthe press from continuous rolls at very high speed. When thepaper strip, or web, breaks accidentally, the press must bestopped quickly or a large amount of paper is lost and cleanuptakes valuable time. To prevent such losses, the integrity of theweb is often monitored by a Dwyer differential pressure switchconnected to a pickup tube opposite a jet of air on the other sideof the web. When the web breaks, the air flow from the jet caus-es pressure to rise in the pickup tube, closing the switch whichsignals the main control unit to shut down the press. The press-man regulates the jet pressure to minimize air consumptionbased on the desired response time.

Yarn

Pull Rollers

Trumpet

CardingMachine

Valve

Air Supply

Photohelic®

Switch/GageHI

Some area pollution control agencies require that 90% or moreof gasoline vapor vented at service stations when fuel is dis-pensed must be prevented from venting to atmosphere. Usinga dual hose dispenser, this vapor recovery system is a vacuumassist, vapor burnoff type. The blower creates a low vacuum atthe nozzle, routing vapor from the automobile tank to under-ground storage tanks. As uncondensed vapor pressure reaches2˝ to 3˝ w.c. pressure, a Dwyer 1950 Series explosion-proofdifferential pressure switch activates a rooftop burnoff unit,which ignites excess vapor. The Magnehelic® differential pres-sure gage mounted on the station wall monitors tank pressureto verify system operation. The gage is calibrated in inches ofgasoline, from +6 to -2. This allows the operator to determinethe necessary level correction due to tank pressure prior to dip-sticking the tanks through the fill pipe.

The size of a “rope” of permeable materials, such as the yarnproduced by carding machines in the textile industry, can becontrolled by air pressure sensed by a Dwyer Photohelic® differ-ential pressure switch/gage. On these machines, the amount offiber supplied for the yarn causes its diameter and density tochange proportionally. The backpressure created by a larger anddenser yarn in the trumpet increases the pressure sensed by theswitch/gage until the preset upper limit is reached and theswitch causes the carding process to slow down. When it slows,the yarn becomes smaller and less dense until the pressure fallsto the switch/gage’s preset low limit and the carding unit is sig-naled to speed up. The amount of air supplied controls thedesired size of the yarn. Opening the valve reduces yarn size byproviding the preset backpressure from a less dense yarn andvice-versa.

A Dwyer Photohelic® differential pressure switch/gage on thisfixture detects breakage of drills or reamers in automaticmachines and shuts down the process immediately uponbreakage. It prevents additional damage where tapping or otheroperations follow in the process. In the fully retracted position,an orifice in the drill guide is located just above the cutting lipof the drill. Regulated air pressure is supplied to the orifice andteed to a Photohelic® switch/gage. As long as the drill is intact,pressure remains high. If the drill breaks, the missing drill tipallows pressure to drop below the minimum set on the gageand the relay closure signals the process to stop. Theswitch/gage will also actuate an alarm if desired. Although asimple differential pressure switch could be used, thePhotohelic® switch/gage is superior for this application, as itpermits instant adjustment for various machine setups.

Yarn size from carding machine controlled byswitch/gage. When paper web breaks on printing press, air jet

reaches pressure switch, which signals control tostop press.

If drill breaks, switch/gage will stop machine. Gasoline vapor recovery system.

ProcessingUnit

DispensingPump

VaporCollection

LineFill

Pipe

GasolineLine

Underground TankCondensateDrain Lines

ReliefValve

HI

1950 Explosion-Proof

DifferentialPressure Switch

Magnehelic®

Gage

WebPress

Rollers

CompressedAir Supply

Air Jet

Paper

PickupTube

HI

DifferentialPressure Switch

Photohelic®

Switch/GageHI

RegulatedAir Supply

Orifice

Drill Bit

Drill Guide

pg 18 12/10/03 6:47 PM Page 1

When using differential pressure transmitters in fluid applica-tions, it is essential to periodically make sure that there is no airin the system, as this can cause erroneous readings.Unfortunately, the necessary three-valve bleed system is oftenexpensive and large, making installation difficult and bulky. Forthis reason, Dwyer offers the 3V option on all 645 Wet/WetDifferential Pressure Transmitters. This compact, lightweight,and economical bleed manifold is shipped factory-installed onthe 645, eliminating the hassle of constructing a custom appa-ratus. The 645, when combined with the three-valve option,makes for an ideal setup to monitor hydraulic filter clogging orother fluid pressure sensing applications.

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Photohelic®

Switch/Gage

Reversible Drive Motor

Adjusting Screw Drive

Adjusting Screw

Seal

LO

VacuumSource

Test Fixture

This laboratory dryer is used to dry small batches of chemicalcompounds, drugs, fertilizers, foods, etc., for research and devel-opment purposes or to prove production techniques. Room air isdrawn in through the pre-filter, passes through the blower andover the heating coils. The blower forces heated air up throughthe material to be dried. The Dwyer Magnehelic® differentialpressure gage A monitors the pressure drop across the materialto detect any blockage developing. The exhausted air then pass-es through a final filter. To monitor the condition of that filter,Magnehelic® gage B measures the associated pressure drop.Minihelic® gages would also be suited to this application.

pressure

This unique toilet tank fill valve replaces older ballcocks andfloats. It is controlled by a diaphragm exposed to the head ofwater in the tank. An adjusting screw allows the installer to setthe correct level of water in the tank for proper flushing withminimum water. During production, this fixture automaticallysets the adjusting screw to a common 18˝ to 20˝ water column.The fixture draws a vacuum on the lower side of the diaphragmto simulate water pressure on the top side and a DwyerPhotohelic® differential pressure switch/gage samples this vac-uum via the low pressure port. With presets at 18˝ low and 20˝high limits, a reversible motor on the fixture engages the adjust-ing screw and drives it to the point where the valve closes in thedesired 18˝-20˝ range.

The pumping station is used to provide water for irrigation purpos-es and contains one to four pumps with a pump control system.To protect the pump a loss of prime protection is included in thesystem. A pressure switch is installed in the system and signals alow pressure alarm. Then if the V6 flow switch signals no flow atimer starts and if there is no flow through the system for a giventime period the pump is shut down. The flow switch by itself alsotrips a low flow condition for pump shut down even if pressuredoes not fall. The A1B-OP is perfect for this application as it wasdesigned to mount in the bottom of the pump station control panel.It mounts flush through the bottom of the panel and comes com-plete with a sealing gasket and nut to make sure the switch sealsoff tightly against the panel keeping it weatherproof. Mounting inthis fashion saves the cost of using weatherproof pressure switch-es. The V6 flow switch is also well suited for this application withits robust and weatherproof design.

Dwyer switch/gage controls tank fill valve setting.

Three-valve manifold simplifies installation ofwet/wet differential pressure transmitter.

Mercoid® A1 pressure switch and W.E. Anderson®

V6 flow switch are incorporated into irrigationpumping station.

Two differential pressure gages reveal filter condition in lab dryer.

Series 645Wet/WetDifferentialPressure Transmitter

Liquid Flow

LO

HI

LOHI

Exhaust

Filter

Material

Air Flow

Heater

Blower

Pre-Filter

Magnehelic® Gage B

Magnehelic® Gage A

Pump

Flow Out

Series V6Flotect®

Mini-Size Flow Switch

Series A1PressureSwitch

Pump ControlPanel

pg 19 12/10/03 6:49 PM Page 1

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pressure

Where dual filters are installed, a single Magnehelic® differentialpressure gage can be used to monitor the condition of each fil-ter, using the arrangement illustrated above. With the knob onthe Dwyer A-365 selector valve pushed in, the static pressuresensors across filter A are connected to the appropriate ports onthe gage. Pull the selector valve knob out and you connect thestatic pressure sensors across filter B to the gage. Be sure toselect a gage range appropriate to the specified pressure dropfor both filters. If desired, substitute a Photohelic® differentialpressure switch/gage or Durablock® inclined manometer for theMagnehelic® gage.

HILO

Magnehelic® Gage

Air Flow

Filter

Static Pressure Sensors

The basic function of this filter testing system is to aid in con-serving energy. It provides accurate comparative data for simi-lar filters to help the operator select or specify the filters thatprovide maximum efficiency with minimum pressure drop. Avariable speed blower draws air through the filter under test.Blower voltage and current are indicated on panel meters. OneMagnehelic® gage monitors static pressure on the blower sideof the filter, and exhaust air velocity is indicated by a secondMagnehelic® gage connected to a Pitot tube in the exhaust duct.For a given air velocity, filter pressure drop and electrical ener-gy required can easily be determined for various filter designs.

A Magnehelic® air filter gage instantly reveals when filters needservicing. Select a Magnehelic® gage model with range appro-priate to the filter manufacturer’s recommendation for maximumpermissible pressure drop across the filter. Install the gage witha red adjustable signal flag (optional) set at the maximum allow-able pressure drop point for the air volume being handled. Thisspeeds the reading of gage, even by relatively inexperienced per-sonnel. Portable kits complete with static tips, tubing and hard-ware are available. Instead of the Magnehelic® gage, ourPhotohelic® differential pressure switch/gage will automaticallyactuate an audible or visual alarm when filter needs servicing.Where a very high degree of accuracy is required, an inclinedmanometer, such as the Dwyer 100 or 200 Series Durablock®

models, can be used to measure pressure drop. If low cost ismost important, our Mark II, Model 25 manometer will indicatepressure drop.

When dust build-up on this roll filter increases the filter’s resist-ance to air flow, the increased pressure drop across the filter issensed by the differential pressure switch, which starts a motorto roll a new section of filter into place. A Dwyer Photohelic®

differential pressure switch/gage can also provide this type ofautomatic control. It has the added advantage of continuousvisual indication of the pressure drop for routine checking bymaintenance personnel, as well as front-mounted knobs forinstant adjustment of high and low pressure limits.

Several types of Dwyer differential pressure gagesare well suited to monitor the condition of filters. Two filters served by one gage and Dwyer selector

valve.

Differential pressure switch actuates roll filtermotor when dust reduces air flow.

Test unit compares efficiency of various filterdesign.

Air Flow

DriveMotor

Roll Filter

Static PressureSensor

Static PressureSensor LO HI

DifferentialPressureSwitch

Static Pressure Sensors

Selector Valve

HI

LO

Magnehelic®

Gage

Air Flow Filter "A" Filter "B"

Magnehelic®

Gages

PressureDrop

AirVelocity

Current VoltageFilterUnder Test

Blower

VariableDC PowerSupply

pg 20 12/10/03 6:50 PM Page 1

Concern for efficiency and safety, as well as compliance withfederal regulations, has produced a need for operator enclo-sures on equipment used in areas with high ambient tempera-tures and heavy air pollution. Such enclosures are supplied withfiltered and conditioned air to insure operator comfort and safe-ty. Dwyer differential pressure switches are specified to monitorthe pressure drop across the filters in the compact, heavy-dutyair conditioners installed in the cabs. The switches actuate avisual or audible warning when filter cleaning or replacement isrequired.

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Spray Booth

Paint Arrestors

Mark II Manometer

LO

Exhaust

Many large commercial warming and baking ovens requireforced air circulation. They are protected against overheatingdue to blower failure or filter clogging by a Dwyer differentialpressure switch, which monitors the pressure drop betweenthe oven cavity and the inside of the fan duct. Should the pres-sure drop exceed the preset standard, the switch will turn offthe oven heaters and light a panel alarm indicator.

pressure

Industrial spray-painting booths equipped with paint arrestorsneed monitoring to indicate when arrestor maintenance isrequired. The low-cost Mark II Model 25 manometer is widelyused for this. Usually, the manometer is mounted to the outsidewall of the booth for easy observation, and the low pressure tapis made directly through the wall of the booth to the exhaust sideof the system. The manometer’s high pressure port is leftunconnected as the area around the spray booth is at ambientroom pressure. A Dwyer Vaneometer can also be used to checkface velocity at the open side of the spray booth.

This portable dust collector can be rolled from job to job in anindustrial building. An operator places the large diameter collectionhose where it is needed and dust is collected by filters locatedinside the access doors on the units side. The top mounted blow-er draws air through the filters. To monitor the pressure dropacross the filters, the manufacturer supplies a Magnehelic® differ-ential pressure gage. When the pressure drop due to dust build upon the filter indicates that cleaning is necessary, the DCT500DCDust Collector Timer Controller is manually activated to initiate acleaning cycle which involves solenoid valves releasing pulses ofair. This process removes the dust from the filters where it dropsinto a storage bin. A Dwyer Minihelic® differential pressure gagecan be used instead of the Magnehelic® gage, and, if automaticcleaning is required, a Photohelic® differential pressureswitch/gage can provide the electrical contact to actuate the clean-ing cycle when the pressure drop reaches the preset limit.

Low-cost Dwyer manometer indicates when tochange filters in industrial paint spray booth.

When A/C filters in operator’s cab need cleaning,a Dwyer pressure switch actuates a visible or audible warning.

Dust Collector Timer Controller shows filter condition in dust collector.

Commercial warming ovens include differentialpressure switch to alert operator if fan fails or filterclogs.

Magnehelic®

Gages

Collection HoseDust Bin

FilterDoor

FilterDoor

Exhaust

Blower

Series DCT500Low CostTimer Controller

DifferentialPressure Switch

LO HI

HeaterFilter

Oven Capacity

Heater

Blower

OvenControlPanel

Air Conditioning Unit

DifferentialPressureSwitch

Operator Cab

pg 21 12/10/03 6:52 PM Page 1

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pressure

The large air cleaners on diesel locomotives must be servicedpromptly when the particulate build-up on the filter elementexceeds a safe level. To monitor filter pressure drop in thisapplication, the engineers specified a Dwyer 1910 differentialpressure switch. It performs reliably despite severe shocks andvibration as well as elevated ambient temperatures. When thepressure drop exceeds the preset level of the switch, a red alarmlight goes on in the engine cab. The alarm is latched in the “on”position, alerting maintenance crews at the destination to theneed for air cleaner service.

Photohelic® Gages

Filter Unit Filter Unit

Hopper

Series DCT500Low CostTimer Controller

A Dwyer DCT1000 Dust Collector Timer Controller with attach-able DCP pressure sensing module monitors and controls thedust levels and corresponding pressure drop across the filterbags. The DCT1000/DCP control automatically activates thecleaning cycle when the DCT1000's pre-programmed set pointshave been exceeded. This on-demand control system alleviatesexcessive air compressor usage by preventing unnecessarycleaning which lowers energy and maintenance costs.

An automatic filter cleaning control system is created with thecombination of the Dwyer Photohelic® switch/gage and aDCT500 Dust Collector Timer Controller. The Photohelic® gagemonitors the filters for dust build-up. When the dust build-upand pressure drop across the filters exceeds a preset limit, thePhotohelic® gage activates the DCT500’s cleaning cycle. TheDCT500 controls the cleaning process until the dust levels andcorresponding pressure drop on the filters falls back below thepreset limit. Static pressure tips and line filters are recommend-ed to prevent migration of particulate into the Photohelic® gage.

This large electric induction motor has rotor mounted fans thatdraw cooling air into each end of the motor, across the rotor,and out through the stator into an exhaust duct. To preventaccumulation of dirt and dust in the motor, incoming air is fil-tered. The condition of each filter is monitored by a Dwyer 1950explosion-proof differential pressure switch which senses thedifferential pressure drop across the filter. An explosion-proofswitch is required since this inherently safe motor design isused to drive gas compressors. If the filter pressure dropreaches a preset high limit, the switch shuts down the motorand signals an appropriate alarm.

Automatic filter cleaning control system.Alarm light triggered by Dwyer pressure switchalerts diesel engine maintenance crews to service air cleaners.

Cooling air for big motor passes through filtermonitored by explosion-proof differential pressureswitch.

Bag house cleaning system uses Dust CollectorTimer Controller to initiate optimum cleaningcycle.

CleanAir OutletFilter Bags

DirtyAirInlet

AirshockBlower

Dust Hopper

Series DCT1000with DCPDust CollectorTimer Controller

DifferentialPressure Switch

HILO

LOHI

Motor Controls

Filter Doors

Air In Air Out

Shaft

pg 22 12/10/03 6:53 PM Page 1

Removal of asbestos material from buildings requires carefulcontainment of airborne fibers generated during the removalprocess. The work areas must be sealed off and maintained ata negative pressure compared to atmosphere to prevent theescape of fibers from the work area. The negative pressure airsystem illustrated above is portable and contains a HEPA filterto remove the asbestos fibers from the “suction” duct prior toexhausting the resulting clean air outside the work space. AMinihelic® II differential pressure gage is utilized to monitor thepressure drop across the filter bank and indicate when cleaningor replacement is necessary. A Series 1910 differential pressureswitch is also sometimes used in parallel with the gage to acti-vate a filter alarm lamp mounted on the system control panel.

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Magnehelic® Gage

Hospital patients who are susceptible to dust or bacteria requirethe services of an “environmental care unit.” Sophisticated airfiltration systems remove particulates from the incoming pres-surized air. A Magnehelic® differential pressure gage monitorsthe pressure drop across the filter system to indicate whenmaintenance is necessary. The Dwyer Mark II manometer mon-itors positive room pressure to insure that adequate pressureabove atmospheric will prevent an influx of unfiltered air whenthe doors are opened. If a dial type readout is desired, aMagnehelic® or Minihelic® differential pressure gage can beused in place of the Mark II manometer. Or, to provide a visualor audible warning of impending problems, Photohelic®

switch/gages can be installed to serve both applications.

pressure

The extensive avionic systems on modern military aircraftrequire cool, conditioned air to remove heat generated by thisequipment. In flight, the cooling air needs are met by the ambi-ent air at higher altitude. However, during pre-flight mainte-nance, the high volume of cooling air must be supplied by easi-ly transportable air conditioning systems like the unit illustratedabove. Critical monitoring of the condition of the air must besupplied by easily transportable air conditioning systems like theunit illustrated above. Critical monitoring of the condition of theair filters used on these portable systems is provided by theDwyer Magnehelic® gage. The Magnehelic® gage easily meetsthe reliability and ruggedness requirements of this application.

In a typical high pressure liquid filter installation, a clean filterelement will have a rated pressure drop for a given operatingline pressure and rate of flow. As the filter accumulates partic-ulate, the resistance to flow increases and the pressure dropincreases until the level is reached when the filter element mustbe cleaned or replaced. The Capsu-Spirahelic gage will indicatethe differential pressure across such filters up to 100 psig. Theby-pass piping and valving permit changing either the filter orthe gage without shutting down the system.

Military flight line air-conditioning system utilizes aDwyer gage to monitor filter condition.

Differential pressure gage monitors filter loading inasbestos removal negative air system.

High pressure gage monitors condition of pipelineliquid filter.

In pressurized hospital rooms, a Dwyer manometerreveals pressure while a Dwyer gage monitors airfilter.

HI

Capsu-SpirahelicGage

Shut-Off Valves

Line Valve

Shut-Off Valves

FlowFilter

Makeup Air

Filter UnitHILO

Magnehelic® Gage

HI

Mark IIManometerMark IIManometer

Filter Bank

Blower &Controls

Minihelic® II Gage

InletDuct

pg 23 12/10/03 6:55 PM Page 1

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pressure/flowModel CS-150Pressure Switch

Lube Oil TankPump

Saw

Since only a small amount of oil is used, the sawdust can berecovered and used as a fuel. The pressure switch (CS-150)sounds an alarm if the oil pressure is lost, preventing severedamage to the saw blade.

Mercoid® model CS-150 pressure switch sensesloss of lubricating oil to saw blade in saw mill andactuates an alarm.

Control panels on hot tubs and spas must have their electronicscompletely isolated from any point where water could enter thesystem; however, control buttons must be easily accessible forproper operation. To accomplish this, pneumatic buttons areused, which when depressed, transfer a pressure through a tubeto a Dwyer MDA or MDS Miniature Pressure Switch. When theswitch senses the pressure, the circuit closes, sending a signalto the control panel to perform the intended function. As such,electronic components can be located in a safe, water-free areaof the system.

Miniature pressure switches ensure safe electronics in spas and hot tubs.

Where it is necessary to prove operation of an exhaust fan, aDwyer differential pressure switch performs well. The simplesttechnique requires connecting only the high pressure switchport to a static pressure tap downstream from the fan, if the fanis located at the beginning of the duct, or the low pressure portupstream from the fan if the fan is located at the end of theduct. The switch senses the slight pressure created by the fancompared to the atmosphere. If the fan is located somewherewithin the duct, we recommend placing sensors ahead andbehind the fan, as shown above. This takes advantage of thehigher pressure differential across the fan to operate the switch.In all three cases, if the fan stops, the switch will signal a warn-ing or start auxiliary equipment.

Dwyer differential pressure switch monitors fanoperation.

DifferentialPressure Switch

LO HI

Exhaust Duct

Static Pressure TapsFlow

Dwyer differential pressure switches are specified to prove theexistence of sufficient cooling air flow in electronic equipment.Large final amplifier tubes in broadcast radio transmittersrequire essential cooling air or overheating will quickly damagethese expensive components. A total pressure pick up placed inthe cooling air stream and connected to the pressure switchcan instantly sense any drop in total pressure due to fan failureor air blockage. It will then sound an alarm or shut down theamplifier before failure occurs or temperature sensors cause aless desirable shutdown.

Dwyer switches protect electronic equipmentshould cooling air flow fail.

DifferentialPressure Switch

RadioBroadcastTransmitter

pg 24 12/10/03 6:56 PM Page 1

The Dwyer 660 Air Velocity Monitor continuously measuresfume hood face velocities to ensure proper ventilation in accor-dance with safety standards. An audible and visual alarm alertsthe user when the lowest allowable safe operating limit of thefume hood has been reached. The 660 has an adjustable lowlimit range of 0-150 FPM (0-0.792 m/s) which allows the alarmpoint to be set in accordance with the proper agency safetystandards. These cabinets often feature a Magnehelic® differen-tial pressure gage on the control panel to monitor static pres-sure in the system as a check on proper blower operations andto monitor pressure drop across the filter to indicate when thefilter should be serviced or replaced.

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Air Flow

ComputerUnit

SupplyAir

MotorControl

VariableSpeedMotor

Fan

Series 641Air VelocityTransmitter

In variable air volume (VAV) HVAC systems, a computerizedcontrol provides precise adjustment of air volume to meetchanging system needs with maximum energy efficiency. TheDwyer Series 641 has an optional LED display for local indica-tion of air flow. The LED display provides a quick, visualacknowledgement of proper system performance. The comput-er reacts to any change in velocity by signaling the motor con-trol to increase or decrease fan speed to maintain the requiredvelocity. The computer, taking inputs from other ambient condi-tion sensors, will establish a new required air velocity and signalan appropriate adjustment in fan speed.

In this cooling application, the Dwyer differential pressureswitch senses the increasing restriction to air flow caused byicing and actuates the defrost cycle. Two static tips are installedto sense the differential pressure across the cooling coils. In alow cost, low voltage and current, high volume product appli-cation, the Dwyer Minitactor® differential pressure switch is aneconomical unit to specify for this type of application. Dwyeroffers six types of stainless steel static tips to suit any applica-tion. In service applications, the Dwyer Trail-Tail® static pres-sure sensor serves to take accurate static pressure measure-ments, as it automatically aligns with duct air flow. The Trail-Tail® sensor, when attached to a length of light tubing, can alsobe used to take measurements downstream from the point ofaccess to the duct.

Dwyer transmitter signals precise air velocityadjustments to computer-controlled variable-speed fan motor.

Ensure proper ventilation by continuously measuring fume hood face velocities.

Dwyer switch senses ice build-up on cooling coilsand actuates defrost cycle.

Magnehelic®

Gage

Fume Hood

Air Flow

HINORMALLOW

Model 660Air Velocity

Monitor

DifferentialPressure Switch

HILO

Evaporator

Air Flow

Static PressureTips

Magnehelic® GageDurablock®

Inclined Manometer

Air Flow

Static Pressure Tap

HILO

Pitot Tube

TotalPressure Sensor

HI LO

To measure air velocity, connect a Dwyer Magnehelic® orMinihelic® differential pressure gage, or a Dwyer Durablock®

inclined manometer to a Pitot tube in the air stream as shown.The alternative method at right requires only a static tap plus asimple tube in center of duct to pick up total pressure. The dif-ferential pressure reading on the gage or manometer is velocitypressure, which may be converted to air velocity by calculationor reference to conversion chart. Where air density is known, thegage manometer can also be calibrated directly in velocity units.If you need an alarm or control function to maintain a preset airvelocity limit, install a Photohelic® switch/gage. Dwyer stainlesssteel Pitot tubes are made in numerous lengths and configura-tions to serve in the smallest to the largest duct size.

Either of two methods used to measure air velocity.

flow/air velocitypg 25 12/10/03 7:00 PM Page 1

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Underground telephone cables are kept under pressure with dryair for protection of the electrical circuits against damage due tomoisture. The flow of air to each cable is monitored to deter-mine proper protection as well as to detect leaks that may devel-op due to cable damage. Special multi-column Dwyer Visi-Float®

flowmeters are widely used in this application. A manifold boredin the flowmeter bank connects the supply air to the bottom ofeach flowmeter through an on-off valve located in each bore.The outlet of each flowmeter then feeds a single cable.

Rate-Master®

Flowmeter

ControlPanel

Sensing total pressure (velocity plus static), the DwyerDifferential pressure switch in this application turns off the ductheater to prevent burning out the heating element if the air flowacross the element becomes insufficient. In some cases, it maybe necessary to sense the negative static pressure upstreamfrom the fan (dotted lines) to develop a large enough differen-tial pressure signal to operate the switch reliably.

Telephone cables, both overhead and underground, are pressur-ized with dry air to increase the reliability of communications byprotecting the cables from moisture. This compressor/dryersystem utilizes a Dwyer RMB Series flowmeter to indicate thepercentage of total system air capacity being delivered to thecable routes connected to the dryer.

Prior to atomizing a heated salt solution to produce a fog insidethis corrosion test cabinet, compressed air is bubbled througha heated water column to properly heat and humidify the air. ADwyer Visi-Float® VFA flowmeter, as part of the system, pro-vides precise adjustment of the bubbler air flow to meet teststandards.

Air delivery source for telephone cables monitoredby Dwyer flowmeters.

Flowmeters used to check dry air flow protectingcables.

Salt corrosion test cabinet includes a Dwyerflowmeter for adjustment of bubbler air flow.

Dwyer switch protects duct heater if air flow fails.

Test ValvesDry Air Supply

Manhole

Underground Cables

AirCompressorandDryer

Multi-ColumnVisi-Float®

Flowmeter

Cable Air Supply Lines

DifferentialPressureSwitch

Heater

Air Flow

TotalPressureSensor

Fan

StaticPressure Tap

LO HI

Test Tank

Controls

BubblerColumn

Visi-Float®

Flowmeter

Clear Plastic Cover

flow/air velocity

pg 26 12/11/03 8:11 AM Page 1

The flow of heated air is held to a constant predetermined veloc-ity in this carefully controlled low temperature process dryingoven. The constant temperature air supply is modulated by a setof inlet louvers operated by a servo-driven actuator. A DwyerSeries 641 Air Velocity Transmitter has an optional LED displayfor local indication of air flow. The LED display provides a quick,visual acknowledgement of proper system performance. Thecontroller compares the Series 641’s signal to the setpoint in thecontroller and continuously signals appropriate louver adjust-ments to the actuator.

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DifferentialPressureSwitch

LO HI

Flow

Oven Hood

Product

Conveyor

The small size, accuracy, and low cost of the Dwyer Mini-Master® Series flowmeter lends itself perfectly to use in thisportable, battery-operated dust monitor. Using a light scatteringelectronic sampler, a small vacuum pump draws air through theflowmeter into the sampling chamber, and the flowmeter veri-fies the proper volume of sample air flow. Readout is digital anddirectly in dust weight per cubic meter of air.

flow/air velocity

In this conveyor fed oven, a differential pressure switch moni-tors the pressure increase across the fan to assure maintenanceof proper air flow. The switch signals a warning or stops theprocess upon failure of the fan. A second differential pressureswitch in parallel - and set for a higher pressure - can providemore complete protection by sensing the greater pressure dropthat would result from blockage of the air intake. To add a capa-bility for continuous visual monitoring by the operator, installDwyer Photohelic® switch/gages for these functions.

Dangerous overheating would occur in this gas-fueled air pre-heater if the blower fails or the air flow is obstructed. To protectagainst this condition, a Dwyer Model 530 air flow switch wiredto the gas supply solenoid valve will close the valve if the airflow fails. A normally closed solenoid valve is specified to pro-vide for fail-safe operation of this protective system. Wherehazardous ambient conditions exist, a W.E. Anderson® ModelV4 Flotect® explosion proof flow switch can also be used. Inaddition, a Mercoid® Model M-51 temperature switch can beused to monitor preheater temperature.

If oven air flow fails, a Dwyer switch stops theprocess.

Air velocity transmitter controls drying oven airflow.

Air flow switch protects preheater from overheating.

Operator uses Mini-Master® flowmeter to verify airflow into portable dust monitor.

Dwyer Model 530Air Flow Switch

Flow

PreheaterGas Supply

NormallyClosedSolenoidValve

Air In

Blower

Probe

SetpointController

Actuator

Air Supply

Conveyor Drying Oven

Series 641Air VelocityTransmitter

Inlet Cyclone

Control Panel

Electronics Section

Mini-Master®

Flowmeter

Air MovingSection

Battery Pack Optical Section

pg 27 12/11/03 8:13 AM Page 1

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flow/air velocity

The efficient operation of heating and air conditioning systemsdepends on delivery of balanced, pre-determined air flow.Permanent measuring stations installed in the ducts enableplant engineers to locate and correct problems before theyaffect efficiency. Such stations can use low-cost Dwyer Mark IImanometers to indicate velocity pressure directly as the differ-ential pressure between averaging total and static pressure tips.The manometer is calibrated directly in CFM, as the duct area ofthe station is known. A dial type Dwyer Magnehelic® differentialpressure gage can be used as an alternative if preferred.

Pickup Unit

Office

Factory

DwyerWind SpeedIndicator

Regulations regarding air pollution levels require continuousmonitoring a source and ambient pollutants in areas wherenoxious gases are generated. Ambient air quality samplers uti-lize either Visi-Float® or Rate-Master® flowmeters to establishthe proper flow of sample or carrier gases into the analyzer. Topmounted metering valves are recommended for flowmetersused in vacuum service to maintain specified accuracy.

The Wind Speed Indicator is a low-cost but durable unit formeasuring wind speed. It includes a remotely located indoorreadout instrument. It incorporates a simple, roof-mountedPitot-tube type sensor and a low-cost inclined-vertical manome-ter. No electrical power is needed - neither external, wind gener-ated or battery. Solidly made, the Wind Speed Indicator hasbeen known to continue functioning in extreme wind and weath-er that destroyed other mechanical-electrical devices. Whereverthe velocity of the wind in either MPH or KPH is required - athome, office, factory, farm or remote sites - the Wind SpeedIndicator is highly useful.

This self-contained flowbench is used to test internal combus-tion engine components such as cylinder heads, intake mani-folds, throttle bodies, air cleaners, etc., for design changes toachieve maximum air flow and minimum pressure dropsthrough critical flow passages. Flow changes as small as 0.5%can be measured. A Durablock® inclined manometer, indicatingpercent of flow, is utilized in conjunction with individualized cal-ibration charts to determine air flow in CFM. Two 48˝ Model1230 well type manometers are also employed, one to set andmonitor test pressure and the other one for port mapping orauxiliary use. These Dwyer manometers offer the necessaryresolution and accuracy to determine the effects of smallchanges in engine design needed to achieve maximum per-formance.

Dwyer Wind Speed Indicator is widely used inhomes, offices, factories, marinas and farms.

Permanent stations indicate air velocity round theclock.

Engine component test flowbench utilizes precision Dwyer manometers to measure testpressures and air flow. Metering valves on Dwyer flowmeters control

air/gas intake on permanent air pollution analyzers.

Air Flow

StaticPressure Tips

Total Pressure Tips

HI LO

Mark IIManometer

Durablock®

InclinedManometer

Dwyer Model1230 Well-TypeManometer

Sample Analyzer

Vacuum PumpFlowmeter

SampleIn Take

MeteringValve

pg 28 12/11/03 8:14 AM Page 1

A chilled-mirror sensor system provides a continuous monitor-ing of dew point in various gas streams or humidity chambers.The sample flows into the sensor under pressure with the prop-er flow rate set by the metering valve on the Dwyer Visi-Float®

flowmeter.

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InclinedVertical

Manometer

Flue Gas VelocityPitot Tube ConnectionGas Sampling Unit

Physicians and oral surgeons who use anesthesia or analgesiain their offices on an occasional basis require a system that isreliable but small and portable. One such system employs spe-cial Dwyer dual-column Visi-Float® flowmeters to meter andmonitor precise flows of nitrous oxide and oxygen to thepatient. In addition to meeting the performance level demandedby this application, the Visi-Float® flowmeters are durable andattractive complements to this important and visible medicaldevice.

Stack sampling regulations aimed at compliance with air pollu-tion standards as well as the practical need for energy conser-vation require the use of many different instruments to make theappropriate measurements. A special Dwyer Durablock® dualcolumn inclined/vertical manometer is used in the control unit ofa portable particulate sampler which can perform all therequired tests and measurements. While the illustration abovedoes not fully represent the complexity of this instrument, themanometer’s primary function is accurate measurement of thegas velocity in conjunction with a Pitot tube assembly in thestack probe.

This low temperature incubator with CO2 atmosphere is used inbio-medical applications, such as short term blood work andlong term tissue culture studies. CO2 is introduced at a high ini-tial purge rate controlled by a timer. After the purge period, aDwyer Visi-Float® flowmeter with a metering valve is utilized toadjust and monitor the CO2 flow in cubic centimeters perminute. The Visi-Float® flowmeter provides the reliability andaccuracy needed to complement the host of high performancefeatures designed into this incubator.

Portable sampler includes Durablock® manometerfor accurate measurement of stack gas velocity.

Instrument for monitoring dew point in gas streamsuses flowmeter with metering valve to control gas.

Designers of a bio-medical incubator rely on aDwyer flowmeter to control CO2 flow.

Durable dual-column flowmeter adds value forphysicians and oral surgeons.

MeteringValve

VentSensor

To Control/IndicatingUnit

FromGasStream

Visi-Float®

Flowmeter

037

Chamber

ControlsVisi-Float®

Flowmeter

Visi-Float®

Dual ColumnFlow

Patient Mask

O2

Tank

N2OTank

flow/air velocitypg 29 12/11/03 8:23 AM Page 1

Heated or cooled air is used for irrigation in certain medical pro-cedures. Precise control of air flow, temperature, and time isrequired. The manufacturers of a device to provide this servicerely on a Dwyer flowmeter to adjust and monitor air flow to theirrigation tip from the pump located in the unit.

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This portable detector pinpoints halogen leaks as the operatorprobes suspected areas and observes the leak indicator. A Mini-Master® flowmeter provides a low-cost means of continuouslychecking that proper suction flow is maintained by an internalpump, so that leaks do not go undetected due to obstruction ofthe probes or failure of the pumping system.

Dwyer Visi-Float® flowmeters are specified to monitor and con-trol the mixture of oxygen and air supply by an infant ventilator.Special scales and oxygen cleaning customize the flowmeter tothis application. The built-in metering valve allows precise set-ting of flow for each gas.

Oxygen concentrator replaces heavy tanks andincludes Dwyer flowmeter for easy adjustment ofoxygen flow.

Designers of a medical irrigation unit specified aDwyer flowmeter to control heated or cooled airflow.

Metering valves on Dwyer flowmeters control pre-cise mix of oxygen and air for infant ventilator.

Small Dwyer flowmeter reveals proper suction flowinto portable halogen leak detector.

Eliminating the need for cumbersome oxygen tanks, an oxygenconcentrator delivers oxygen to the patient from the surround-ing air. This is a great convenience and cost savings for thosewho frequently require oxygen at home. A Visi-Float® or Rate-Master® flowmeter with a metering valve is placed in the oxygenoutput line, so the patient can easily adjust the flow to the pre-scribed level.

Visi-Float®

Flowmeter

MeteringValve

Decorator CabinetHousing Concentrator

Oxygen to Patient

Probe

LeakIndicator

Mini-Master®

Flowmeter

Visi-Float®

Flowmeter

Air ControlTip

IrrigationTip

Visi-Float®

Flowmeters

VentilatorControl Unit To Patient

flow/air velocity

pg 30 12/11/03 8:24 AM Page 1

The Mini-Master® flowmeter is ideal for this small in-line oxygenflowmeter used to set and indicate proper flow of oxygen topilots and passengers flying at higher altitude in small aircraft.To conserve oxygen and reduce the drying effect of excess oxy-gen on the nose and mouth, the exact required flow can be setusing this device. The user simply holds it in a vertical positionand adjusts the needle valve on the Mini-Master® flowmeter fora float position equal to the flight altitude. The needle valve andflowmeter connections are contained in the small housing. Theentire unit can hang from an overhead oxygen outlet by the con-necting tubing or dangle in any position after proper flow hasbeen set.

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DifferentialPressure Switch

LOHI

Purge Gas Supply

Rate-Master®

Flowmeters

Switchbox

Motor Generator

A portable device that meters and humidifies oxygen requiredby a patient at home also provides convenience of movementaway from the oxygen source. A Visi-Float® flowmeter with ametering valve allows the patient to see the prescribed flow.This flowmeter’s small size and light weight, as well as its smartappearance, make it well suited to the portability requirementsof this device.

To purge motors, generators, switchgear, and industrial instru-ment cases, Dwyer flowmeters are installed in the supply line toindicate a flow of air, manufactured inert gas, or nitrogen tothese devices. The flowmeters (with valves) allow maintenancepersonnel to set the flow quickly and recheck anytime to makesure proper flow continues. A Dwyer differential pressure switchcan also be used to monitor proper flow on a continuous basisand provide a signal or alarm if purge gas flow fails. Such anoptional switch is shown above, monitoring proper flow ofpurge gas to the switchbox as a function of pressure dropacross the flowmeter. The purging of electrical equipment inhazardous areas may require more extensive control and moni-toring devices.

A total of eleven Dwyer Rate-Master® flowmeters function in thedesign of this sophisticated conveyor belt furnace used in man-ufacturing electronic devices. The flowmeters provide preciseadjustment and monitoring of the flows of air and gases intothe various portions of the furnace, which allow it to performdifferent operations, such as decarburizing and oxidizing,metallic package sealing, glass package sealing, and glass-to-metal sealing.

Flowmeters and/or differential pressure switchesmonitor vital purge gas flow to motors, switchgear,instruments.

Oxygen supply in small aircraft controlled by acompact Dwyer flowmeter.

Flows of air and gases used in a special furnaceare controlled by Dwyer flowmeters.

At-home patients can set metering valve on aflowmeter to deliver needed flow of humidifiedoxygen.

Furnace Control Panel

Rate-Master®

Flowmeters

Conveyor

Visi-Float®

Flowmeter

MeteringValve

From OxygenSource

Oxygen to Patient

Humidifier

To Face Mask

Housing

From Oxygen Supply

Mini-Master®

Flowmeter

Needle Valve

flow/air velocitypg 31 12/11/03 8:31 AM Page 1

DuctAir Out

Air In

Series 471Digital Thermo-Anemometer

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flow/air velocity

Patient breath sampler uses Dwyer flowmeter toadjust flow rate of expiration breath sample.

Determine air velocity and temperature levels inducts or air supply grills.

Continuous monitoring of the CO2 in the expiration breath of apatient in intensive care or under anesthesia provides a rapidindication of changes in metabolism due to respiratory or circu-latory problems. The designers of this monitoring device speci-fied our Visi-Float® flowmeter to permit adjustment of the prop-er breath sample flow rate induced by a vacuum pump in themonitor.

Digital Display

Filters

Visi-Float®

FlowmeterRecorder

The Dwyer Series 471 Digital Thermo-Anemometer is the idealportable product for determining air velocity and temperaturelevels in ducts or air supply grills. The 471-1's versatility is dueto its four field selectable ranges from 0-500 fpm (0-3 MPS) upto 15,000 FPM (70 MPS). With a push of a button, FPM andFahrenheit readings are converted to MPS and Celsius.Readings may be stored and retrieved which allows the usergreater efficiency with HVAC balancing at various locations in abuilding. Model 471-2 has an extendable probe and model 471-3 pro-vides a bendable extending probe for hard to reach samplinglocations.

In this set-up, the Magnehelic® gage measures higher air veloc-ities as a function of the pressure drop across a sharp-edgedorifice plate in the pipe. The pressure drops can be converted toair velocity using orifice plate data supplied by the manufactur-er. Details regarding available sizes, ranges, installation, andlimitations are available from orifice plate manufacturers andfrom standard handbooks. A Dwyer Durablock® inclinedmanometer or Photohelic® differential pressure switch/gagecan also be used. In addition to the visual reading gage, thePhotohelic® switch/gage provides an alarm signal or shutdowncontrol function. Pressure sensing taps should be located onthe side or top of the pipe or duct to prevent condensation fromdraining into sensing lines or gages.

Measuring air velocity with an orifice plate.

Flow

Orifice Plate

Duct

Static Pressure Taps

Magnehelic®

GageLO

HI

A small flow nozzle with an egg crate air straightener locatedupstream in a large duct provides an accurate, easily construct-ed air velocity measurement system. Air velocity distribution atthe point of discharge across the outlet of nozzle is uniform, andstatic pressure is zero (atmospheric). Consequently, in the lowflow area upstream from the nozzle, static and total pressure atnozzle outlet. As a result, the air velocity and/or volume of flowis easily calculated. The Dwyer Magnehelic® differential pressuregage or manometer can be calibrated to read air velocity or vol-ume directly - assuming standard or constant air density (i.e.temperature, humidity, and pressure). A Photohelic®

switch/gage can be used if an alarm or control function isrequired at a given air velocity or volume.

Measuring velocity or volume of air flow in duct.

Magnehelic® Gage

HI

NozzleEgg Crate Staightener

Air Flow

pg 32 12/11/03 8:32 AM Page 1

Handheld anemometers are an excellent, portable tool for per-forming tests on HVAC system performance; however, largerotating vanes can prevent easy access to ducts. Dwyer intro-duces the MVT Mini-Vane Thermo-Anemometer to eliminatethis problem. With its 1/2˝ diameter vane, the MVT simplifiesprobe entry into the duct. Traversing measurements, which aredifficult or impossible with other anemometers, are made easywith the MVT’s telescoping, extendable probe. Additionally,simple keypad programming enables the user to view volumet-ric flow rates in CFM or CMM. Datalogging software is alsoavailable to easily record and view data on a PC or laptop.

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NCOO

Blended Gas

Food Perishables Preservation

22 2 2

Series MTF

Installing air velocity measurement systems can be a burden-some process – specifying Pitot tubes, static pressure tips, ori-fice plates, differential pressure transmitters, etc. Dwyer offersthe PFS Smart Air Velocity Transmitter to consolidate thesecomponents into one convenient instrument. The PFS can beeasily installed into the duct or air stream to accurately meas-ure air flow while providing local indication as well as linearanalog output. Microprocessor-based technology ensuresaccurate, repeatable results while state-of-the-art softwareallows for volumetric calculations and datalogging functions.The PFS combines these features for simple, reliable airflowmeasurement without the problems associated with complex,traditional systems.

For blending or metering different gases, Dwyer’s MTF MultitubeFlow Systems are some of the industry’s most reliable andrequested products. Food packaging is one of many applica-tions which require precise mixing of several gases. Oxygen,N2, CO2, and other gases are blended and injected into the pack-aging of perishable products to optimize the shelf life. The gasmixture replaces the previously evacuated air, providing the nec-essary preservation. By merging high precision valve technolo-gy with flowtubes that can be correlated to almost any gas, theproven design of the MTF imparts accurate gas measurementand control.

Dwyer GFC Gas Mass Flow Controllers are ideal for numerousapplications where high accuracy gas flow control is required.Ice cream producers must generate an exact 50% air-to-creamratio in order to comply with federal regulations. The GFC canmeasure the mass of air injected into the mixture, freeing oper-ators from lengthy and potentially inaccurate proceduresinvolving volumetric meters with manual valves. Dwyer GFC’sare equipped with precision valves which can be controlledlocally by an operator or remotely using industry standard ana-log signals. The controller also outputs an analog signal pro-portional to the flow rate for remote monitoring purposes.

Enable accurate metering of gases in preservationof food perishables with Dwyer Multitube FlowSystem.

Handheld anemometer enables traversing ductflow measurements with a miniature vane andtelescoping probe.

Provide simple, accurate flow control of variousgases for many applications with a Gas Mass FlowController.

Eliminate the need for Pitot tubes, static pressuretips, orifice plates and differential pressure sensorswith a Smart Air Velocity Transmitter.

Air Flow

Series MVT

Ice Cream

Series GFCNitrogen

Air Flow

Series PFSSmart AirVelocity Transmitter

flow/air velocitypg 33 12/16/03 4:00 PM Page 1

Valve

Bleed Fittings

LO HI

Capsu-Photohelic®

Switch/Gage

Electrical Lead to Control Room Indicators

To insure the vital flow of cooling water to a large engine, a W.E.Anderson® V4 Flotect® flow switch can be placed in the coolingwater line. It will sound an alarm if the flow falls below a safeminimum, or can even be connected to shut off the engine.

Alarm

Engine

HeatExchange

Flotect® Switch

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This W.E. Anderson® V4 Flotect® flow switch has an optionalNeoprene boot (inside the pipe) to protect the vane hinge froman accumulation of solids. Installed on a storm sewer lift pump,the switch will stop the pump motor when flow ceases or fallsbelow the set minimum, preventing pump cavitation and wast-ed power.

flow/air velocity

Large air conditioning and refrigeration systems which includewater cooled condensers require that the water must circulatethrough the condenser and cooling tower in sufficient volumebefore the compressor is started. Here the W.E. Anderson®

Flotect® flow switch is connected to the compressor control cir-cuit to prevent starting or to shut down the compressor controlcircuit if the flow of cooling water falls below that required forproper operation. A dual Flotect® switch (available as an option)will also trigger a remote alarm to signal the operator of theshutdown as soon as it occurs.

Zero-center switch/gage on pipeline signals flowdirection to remote control room.

If cooling water flow fails, Flotect® flow switchsounds alarm or stops engine.

Flotect® flow switch ensures cooling water circulation before air conditioning compressormotor starts. One of many options, a Neoprene boot over

Flotect® flow switch vane hinge protects it frombuildup of solids.

When used with water or other compatible liquids, a brass bodyDwyer Capsu-Photohelic® differential pressure switch/gageserves as a simple, reliable flow direction monitor. It will signalflow direction in a pipeline at a remote location, such as in a con-trol room. Taps in the wall of the pipe on each side of a conve-niently located valve provide a method to indicate a small pres-sure drop due to a slightly restricted flow even when the valve isfully open. A low range zero-center Capsu-Photohelic®

switch/gage registers flow in one direction as an upscale read-ing and opposite flow as a downscale reading. With the set-points adjusted each side of zero and consistent with the pres-sure drops involved, the switch/gage relay closure provides therequired control of the flow direction indicators.

Gate Valve

PumpCheck Valve

Flotect® Switch

Alarm

Cooling Tower

Flotect®

Switch

CirculatingPump

Condenser

Air ConditioningUnit

pg 34 12/11/03 8:35 AM Page 1

In this gravity feed system delivering liquid fertilizer to portabletanks, a Midwest Model 100 sight flow indicator was installed.The operator can see the rotating vanes to check for adequateflow at any time.

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Flowmeter

Metering Knob

Concentrate

Water Supply

Pump

Shut-Off Valve

Mixture Out

Mixing Tank

This compact automatic distilling unit provides a small, butcontinuous supply of ultra-pure water for laboratory use. Usinga Dwyer Visi-Float® flowmeter with a metering valve, the oper-ator sets the proper boiler feed water flow consistent with labrequirements up to the rated capacity of the still in liters perhour. When the distillate receiver is full, a level sensor actuatesa solenoid valve which shuts off the feed water flow. A Rate-Master® flowmeter can serve equally well in this application.

When adding a chemical concentrate to a large volume of wateror other fluid, you can determine the rate at which the concen-trate is being added by using either a Dwyer Rate-Master® orVisi-Float® flowmeter. The concentrate is added on the input sideof the pump. This draws the concentrate from its container andalso utilizes the mixing action of the pump. While a meteringvalve is built into the flowmeter, a separate valve permits com-plete shut-off of the concentrate flow, if necessary, without dis-turbing the flow rate setting. Typical applications of this set-upinclude adding medicine to livestock water and detergent topressure washers or car wash installations. Concentrates must,of course, be compatible with the plastics used in the flowmeterbodies.

In this emergency industrial shower, a V4 Flotect® flow switchhas been mounted in the water supply pipe. It will activateeither an audible or visual alarm (or both) to summon helpwhen the shower is used by an employee who has been acci-dentally contaminated by hazardous material.

Flowmeter controls flow rate of a chemical concentrate.

W.E. Anderson® Midwest Sight Flow Indicatorreveals flow or stoppage.

Use of this emergency industrial shower automati-cally actuates W.E. Anderson® Flotect® flow switchwhich sounds alarm to bring help.

Operators of this laboratory still use the meteringvalve on a Dwyer flowmeter to set desired feedwater flow.

Storage Tank

Portable Tank

Valve

MidwestSight FlowIndicator

Flotect® Switch

Shower Head

AlarmWater Supply

Valve

Condenser

Boiler

Flowmeter

Controls

flow/air velocitypg 35 12/11/03 8:39 AM Page 1

Proper metering of the amount of chlorine added to swimmingpool water is necessary to avoid irritation to the swimmer andexcessive cost due to using too much chlorine. It also ensuressufficient flow to maintain proper sanitation. A Rate-Master®

flowmeter provides a low cost but rugged metering device forthis application. Filtered water is tapped from the main pool sup-ply pipe and delivered to the chlorinator at the proper flow rateby the built-in metering valve on the Rate-Master® flowmeter. Itthen returns to the heated pool water supply line. When usingplastic flowmeters such as the Rate-Master® Series for meteringchemical solution, try to locate the flowmeter upstream of thechemical additive if possible. This will minimize compatibilityproblems between the chemical and the plastic body of theDwyer flowmeter.

Rate-Master®

Flowmeter

Metering Valve

FilterTo Pool

Pump From Pool

Chlorinator

Heater

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This mobile concrete mixer transports the unmixed materials tothe job site and then prepares the concrete, delivering the exactamount and the proper formulation required for the specific job.On the control panel at the rear of the truck mounted mixer,Dwyer Rate-Master® flowmeters permit setting the properadmixture flows to add the specified quantities of accelerators,retarders, air-entraining agents, etc.

flow/air velocity

Continuous monitoring of fuel oil viscosity is required in somecombustion control systems. In this application, a constantflow pump forces a sample of the fuel oil through a capillarytube under temperature controlled conditions. A Capsuhelic®differential pressure gage measures the pressure drop acrossthe capillary and, with the fuel oil at a constant temperature, thegage can be calibrated to read viscosity directly. If automaticviscosity control is desired, a Dwyer Capsu-Photohelic® differ-ential pressure switch/gage will actuate appropriate valve open-ings and closings electrically.

When main pump fails, Flotect® flow switch transfers to standby pump to maintain vital fluidcirculation.

Flow of filtered water to pool chlorinator controlledby metering valve on economical Dwyer flowmeter.

Fuel oil viscosity in pipeline is visually indicated byDwyer gage or controlled by switch/gage. Flowmeters on industrial mixers show flow of

special additives.

When proper fluid circulation in a system is critical, the W.E.Anderson® Flotect® flow switch will automatically start a stand-by pump should the main pump fail. The flow in the main pathof the parallel system illustrated keeps the Flotect® flow switchin an open position. When the main pump fails, the flow willcease. The flow switch then closes, starting the standby pump.

Check Valve

Main Pump

Supply

Standby Pump

Check Valve

Check Valve

Return

Flotect® Switch

Water

Sand

Stone

Cement

Rate-Master® FlowmetersLO HI

Pipeline Flow

Pump

Capillary Tube

BleedFittings

Capsuhelic®

Gage

pg 36 12/11/03 8:50 AM Page 1

In a liquid process high pressure line, the process may beadversely affected by flows above (or below) the desired flow.The W.E. Anderson® Model H3 can monitor flow in systems withoperating pressures up to 1500 psig as a function of pressuredrop across a calibrated orifice plate. The H3 set point is adjust-ed so that an alarm sounds or the process is automatically shutdown if flow exceeds (or falls below) the desired rate. liq

uid

37

LOHI

Capsu-SpirahelicGage

Shut-Off Valves

Orfice Plate

A calibrated orifice plate located in a pipeline will create a pres-sure drop which can be measured up to 100 psig with a Capsu-Spirahelic differential pressure gage. The pressure drop can beread directly in psig or translated into flow units such as gallonsper minute, barrels per day, etc., and read directly on a special-ly calibrated scale designed to meet customer specifications.

This aircraft de-icer saves time and heating fuel by heating onlythe fluid dispensed, not the entire tank. With the de-icing fluidheated by three large heat exchangers operating in parallel, de-icing can begin within 90 seconds regardless of ambient tem-perature. Three W.E. Anderson® Model V6 flow switches areused to sense adequate flow of de-icing fluid through the heatexchanger, one switch on each exchanger. Should fluid flow beinterrupted or drop below a safe level, the burner for the affect-ed heat exchanger will shut down. The V6 flow switch is wellsuited to this application because of its reliability and inherent-ly weatherproof design.

A differential pressure gage measures pipelinepressure drop over orifice plate.

Pressure switch monitors flow in high pressure system.

W.E. Anderson® flow switch protects aircraft de-icing equipment.

Brianair

W.E. Anderson®

V6 FlowSwitch

H3 DifferentialPressure Switch

LO

HIOrificePlate

Line Flow

Line

If ice builds up inside water chiller, or if tubes become restrict-ed, differential pressure across chiller increases. Differentialpressure switch Series H3 senses the increase and actuates analarm. Switch is typically set between 10 and 20 psid.

W.E. Anderson® H3 explosion-proof differentialpressure switch protects water chiller.

Chi ller

H3 Differen tial Pressure Switch

Normally Open

144 psi45° F

Normally Open

150 psi55° F

flow/air velocitypg 37 12/11/03 8:52 AM Page 1

The Dwyer Series UV Ultra View™ Polysulfone flowmeter is anindustrial, highly accurate flowmeter with excellent physicalproperties and wetted parts. The Series UV possesses all plas-tic wetted parts which include polysulfone, Viton®, and PTFE.There are no metal wetted parts that can possibly corrode overtime. Best suited for water purification systems such as reverseosmosis or de-ionized water systems, the Series UV monitorswater that is passing through the purifying membranes.Depending on system size, rates may be a few GPM up to 40GPM or more. Several ranges of the Series UV are available tosatisfy these various sizes.

Series SFI-800Sight Flow Indicator

Drum

WaterTank

Series V12Flotect® Flow

Switch

Water PurifyingReverse OsmosisSystem

Series UVUltra-ViewTM

Polysulfone Flowmeter

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The treatment system exposes water to UV (ultraviolet) lightthat disinfects it. UV light has been shown to kill bacteria andpathogens and has become a viable method for water treatmentthat eliminates the need to use chemicals such as chlorine.Incorporated into the design of the system is an SFI-800 tomonitor the flow rate of the water through the system. The SFI-800 has a visual indication of flow and a linear voltage outputof flow rate used to control the flow. Controlling the flowthrough the system is important to make sure the water isexposed to the UV light the proper amount.

flow/air velocity

Ready mix concrete is delivered in a large truck with a rotatingdrum that keeps the concrete from hardening. Also on thetruck is a tank for storing water that is used to keep the con-crete at a proper moisture level. An SFI-800 sight flow indica-tor and transmitter is installed in the water line between thewater tank and the drum to monitor the amount of water added.The SFI-800 has a pulsed output that can be used for flow rateand flow totalization. A display in the cab of the truck allows theoperator to monitor the flow from the SFI-800. Also on thetruck is a hose line connected to the water tank, which is usedto clean the concrete chute and any spills at the constructionsite. A V12 flow switch is installed in the hoseline to indicatethat water is flowing out of that line. The SFI-800 is perfect forthis application since it has a weatherproof transmitter packagethat is removable and replaceable in the field.

Suction system that removes fluids from hospitalpatients includes a flowmeter with top meteringvalve.

Ultra pure flowmeter for water purification equipment.

W.E. Anderson® Series SFI-800 and Series V12 indicate water flow in a concrete delivery truck.

W.E. Anderson® Series SFI-800 indicates water flowin water treatment processes.

Many hospital rooms are equipped with vacuum lines to providesuction for removing fluids from patients. One disposable fluidcontainer system for use with these in-room suction outletsemploys a Dwyer Visi-Float® flowmeter with built-in top mount-ed metering valve. Using this valve, the attending nurse can setthe prescribed rate of suction flow for each patient’s need. Thiseliminates the guesswork employed when the wall valve alone isused for flow regulation. Often, the latter can result in eitherinsufficient suction to remove all fluid or tissue damage if toomuch suction is applied. Top mounted metering valves are rec-ommended for flowmeters used in vacuum service to maintainspecified accuracy.

Metering Valve

Container withDisposable Fluid Bag

Suction to Patient

CentralVacuumSystemWallOutlet

Visi-Float® Flowmeter

Series SFI-800Sight Flow Indicator

Inlet

Outlet

pg 38 12/11/03 8:54 AM Page 1

A Dwyer brass body Capsuhelic® differential pressure gage,required for water service to prevent corrosion damage to thegage, is used in conjunction with a Dwyer Series DS-300 aver-aging Pitot tube. The Capsuhelic® gage provides a basic methodof measuring water flow rates. As a guide in selecting the appro-priate Capsuhelic® gage range, the designer can consult dataprovided with the DS-300 averaging Pitot tube. This relates dif-ferential pressure in inches of water column to the water flow ingallons per minute for the pipe size involved. The gage can becalibrated directly in GPM if desired. Bleed fittings installed inthe top ports of the gage are recommended to facilitate removalof air from the system. liq

uid

39

Flowmeter

Regulator

Flowmeter

Regulator

HI

LO

Air/Gas Supply

Flow

Orifice

Magnehelic®

Gage

By indicating flow of cooling water to engines, compressorsand other machinery, Sight Flow Indicators permit the operatorto monitor the proper flow to protect the equipment. Engine fuelflow can be measured with a flowmeter. The Dwyer VFAflowmeter series is compatible with and can monitor the lowflows encountered in fuel oil systems. W.E. Anderson® Flotect®

switches (not shown), when inserted in the cooling water lines,can provide an alarm or system shutdown should the flow fallbelow a safe limit.

Dwyer Magnehelic® differential pressure gages can be used asorifice meters in corrosive gas or liquid applications by purgingthe orifice with air or inert gas under pressure to protect thegage from direct contact with fluid and also prevent cloggedmeter lines. The gage is shown connected to two Dwyer flowme-ters with constant differential pressure regulators supplyingpurge air or gas to both the low pressure and the high pressuretap lines. Our Photohelic® differential pressure switch/gage canalso be used to position motorized control valves using a nullband control mode, thus maintaining the proper rate of flowthrough the pipeline for varying conditions.

When the liquid in this supply tank is exhausted, the W.E.Anderson® V6 Flotect® switch senses the loss of flow and stopsthe pump motor, preventing pump cavitation and saving ener-gy.

Purging orifice sensing lines with air permits use ofa Dwyer gage as an orifice meter on liquid pipelines.

Brass body gage measures water flow rates.

W.E. Anderson® Flotect® switch stops pump whenflow stops.

Fuel and cooling flow to large engines and com-pressors monitored by Dwyer flowmeter and W.E.Anderson® Sight Flow Indicators.

LO HI

Capsuhelic®

DifferentialPressure Gage(Brass Option)

Bleed Fittings

Series DS-300Averaging Pitot Tube

Water Flow

Liquid Out

Flotect®

Switch

Pump

Supply Tank

Engine

WaterFlowHeat

ExchangePump

Anderson®

Sight FlowIndicator

Fuel

Visi-Float®

VFA Flowmeter

flow/air velocitypg 39 12/11/03 8:55 AM Page 1

liqu

id

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flow/level

Plastic injection molding requires tight regulation of system tem-peratures to ensure perfect production. Overheating of molds is acommon cause of production shutdowns and can result in faultyparts or even damaged molds. When installed into the mold cool-ing lines, Dwyer P-Series Flow Switches protect the expensiveequipment by ensuring flow. If flow drops below the required rateor ceases entirely, the flow switches will enable system shutdownor alert an operator of the urgent situation. The switches can alsoensure that water flow is turned on before the process begins bypreventing start-up procedures until adequate flow is reached.

ValveMan ifold

Coo ling Wate rSupply Line

Dwy er P-SeriesFlow Switches

Maintaining adequate flow rate is a critical factor in chemical andpaint spraying systems. If fluid flow is inadequate, surfaces maynot be covered evenly or efficiently. System pumps can also bedamaged when flow falls off. A Dwyer P-Series Flow Switch canprevent these problems by indicating inadequate or fluctuating flowrates. By inserting the switch into the control circuit, system oper-ation will cease before the equipment is allowed to function improp-erly. P-Series Flow Switches are ideal for this type of applicationbecause of their in-line design, high pressure limits, and easy instal-lation and maintenance.

Dwyer P-Series flow switches protect pumps andensure proper system operation in chemical andpaint spaying processes.

Dwyer P-Series Flow Switches prevent overheatingof molds by ensuring water or coolant flow in injection molding machinery.

Chemicals/Paints

Filter

Valves P-SeriesFlow

SwitchSprayNozzle

RemoteTerminalUnit

To Control Center

Flotect® FlowSwitch

Mercoid®

WeatherproofDA SeriesPressure Switch

Flow

GroundWaterPump

Municipal water systems supplied by deep wells located atmany locations throughout the system require reliable alarmsat each pump in case of low suction or high discharge pressureconditions. Many systems also employ a Flotect® flow switchfor added low suction alarm evidenced by low or no water flow.Both switches signal alarms to a remote terminal unit at thepumping location which, in turn, relays the alarm conditionsand location to the central water system control station. Theintegral weatherproof construction of the Flotect® switch andoptional weatherproof DA switch housing allow these controlsto be located at outdoor pumping stations.

Flow and pressure switches protect large municipal water system pumps from damage.

Water Treatm ent

Chlorine F low

Mod el UF

Flow measurement of chlorine is a critical process in watertreatment facilities. Using in-line flowmeters can prove to bevery difficult due to the corrosive nature of the liquid. Aportable Dwyer UF Ultrasonic Flowmeter can simply bestrapped onto the outside of a pipe to accurately measure theflow rate of chlorine without ever coming into contact with thesubstance. Since Dwyer’s ultrasonic flowmeters are easilyinstalled and removed in seconds, they can be used to measureflow at different points in the process or even on completely dif-ferent pipe sizes, eliminating the need for cumbersome fittingsand threaded connections.

Water treatment facilities measure the flow rate ofchlorine non-invasively with ultrasonic flowmeters.

pg 40 12/11/03 8:57 AM Page 1

pro

ce

ss/liqu

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41

The W.E. Anderson® L4 float switch provides a simple, reliablemeans for monitoring and controlling the level of a liquid in alarge tank. In this holding tank application, the lower L4 indi-cates to the operator that a tank fill cycle is required; the L4 canalso control the necessary valve or pump to provide an auto-matic fill cycle. When the level of the liquid reaches the upperL4, the switch activates another indicator lamp or terminatesthe automatic fill cycle. The L4 float switch in optional stainlesssteel is recommended for level control of corrosive liquids,while the lower cost standard brass L4 serves well in mostwater and oil applications.

level

A hydro-pneumatic tank with a deep well pump maintainsdesired pressure in a water system. The pump, however, deliv-ers entrained air along with makeup water, requiring periodictank venting to prevent excess pressure buildup. As both waterlevel and tank pressure must be maintained, one side of the W.E.Anderson® Duotect® pressure switch is interlocked with the W.E.Anderson® L4 float switch via the control box. When tank pres-sure falls below the preset system pressure due to water draw-down, the Duotect® switch starts the pump and transfers controlto the float switch. When the preset water level is reached, thefloat switch turns the pump off. If entrained air has increased thepressure beyond the limit set in the other side of the Duotect®

pressure switch, after a time delay covering several normalcycles, then the switch will open the solenoid valve and vent thetank down to proper pressure.

Switches control water level and tank pressure.

Reliable float switches monitor and control liquidlevel.

Vent

Solenoid Valve

Pressure Tank

Well Pump

ControlBox

Duotect®

PressureSwitch

L4 FloatSwitch

Fill Pipe

High LimitL4FloatSwitch

Indicator Lamps

ControlPanel

L4Float Switch

LowLimit

Drain

Silo

Transpor ter

Receiving Bin

Series PLSPaddle

Level Switch

Pneumatic conveying systems use air to transport powderand dry bulk solids through conveying lines. The air is pres-surized by positive pressure or vacuum to move the productthrough the lines into and out of silos, transporters, andreceivers. Typical applications have high and low level indica-tion in the storage bins to control the flow of product in or out.The PLS is perfect for level use in these storage bins. It hasa rotating paddle that is inserted into the bin. As the productlevel builds up in the bin it stops the paddle from rotating andtriggers the level output. The PLS is great for this applicationas it not affected by pressure changes in the bin.

Proximity® Series PLS is used to indicate level statusin pneumatic conveying systems.

Series MPCPump

Controller

InletOutlet

Series PBLTLevel Transmitter

Submersible Pumps

Mercoid® pumpcontroller with level transmitter control pumpsin wastewaterlift stations.

Lift stations are used to transmit wastewater to the treatment facility.Wastewater is transmitted by gravity feed so it has to be continuallyelevated to provide height to generate the flow. Lift stations are pitslocated at points in the wastewater system to collect the wastewaterthat usually have two submersible pumps. Wastewater in the lift sta-tion is pumped out to a higher level from where it can flow on to thenext lift station or to the treatment facility. The Mercoid® Series MPCpump controller is used with the Series PBLT level transmitter to con-trol the level in the lift station. The PBLT is a level transmitter that issubmersed in the tank and sends a linear output of the height of waste-water above it. The MPC takes the height input and controls the pumpsaccording to how it has been programmed. For a lift station, the pri-mary pump comes on when the tank hits a high level and turns offwhen the level decreases to the set low level. The second pump is usedif the first pump cannot drain the station and comes on at a set higherlevel above pump 1. High and low level alarms, submersible pump sealfailure indication, pump over temperature protection, and pump alter-ation all are built into the MPC.

pg 41 12/11/03 9:01 AM Page 1

Magnetic Diaphragm BinLevel Indicators

SS

F

F

F

High & IntermediateLevel Switches

High LevelAlarm

Low Level Switches

Low LevelAlarm

A magnetic coupling completely seals the switch(es) in thehousing from the product and environment, ensuring high reli-ability and enhanced safety. Alarm capability is depicted above.Side mounted flange models are applicable for all bin levels.Top-of-the-bin suspension-mounted models for high and inter-mediate point level provide improved sensitivity (in materialswith bulk densities as low as 5 pounds per cubic foot), andenhanced vertical adjustment capability compared to flange-mounted models. Elastomeric diaphragms are typically used inproducts such as fly ash, plastics, grain, powders, foundrysand, cement, aggregate, coal, metal chips, and glass. For pneu-matic (pressure) applications the porous filter fabricdiaphragms eliminate venting requirements due to an inherentability to breathe. Many different diaphragm materials are avail-able to fill the wide variety of needs in the industrial market.

liqu

id

42

In the example above, a pressurized holding tank in the processsystem is replenished with the process media by a supply lineand electrically operated valve. The valve is controlled by aMercoid® 215 level control which can operate at system pres-sure to 300 psi at 500°F and features an adjustable level changefrom 1-1/2˝ to 24˝. The temperature of the media in the holdingtank is monitored by a Mercoid® DA Series bulb and capillarytemperature control which has independent, externallyadjustable high and low setpoints. The temperature control canactuate an alarm should the media temperature exceed thedesired limits. A well in the side of the tank protects the bulbfrom the system pressure as well as allowing removal of thebulb and control without disrupting the process.

level

Fuel oil and paint liquid level switch applicationsrequire the Proximity® Sliquid™ pressure sensitive,magnetic diaphragm switches with one, two, orthree precision switches.

Proximity® explosion-proof Ultra-Mag™ level switches provide powder and bulk solids level monitoring with suspended (“S”) or flange (“F”)mounted models.

Chemical waste andpetroleum recycling areapplications for theProximity® S-D™ model,pressure sensitive mag-netic diaphragm liquidlevel switches.

Mercoid® level and temperature controls find wideapplication in high pressure and temperatureprocesses.

A 3-switch Proximity® Sliquid™ model in the fuel oil applicationabove turns a fuel pump on at low level (12˝), turns the pump offat high level (48˝), and activates the emergency shutoff at 51˝. Inthe paint storage application shown, a 2-switch Sliquid™ modeloperates a low level alarm (6˝ above the control) in an automatedpaint system. The high level switch activates a high level alarmwhen the paint level is 5’ above the control. This unit can beapplied for point levels up to 200 in. w.c. In the fuel oil applicationshown, a dip tube provides non-contact liquid level control. Aflange-mounted contact method is illustrated in the paint applica-tion. Field adjustment is simple with high and low level springsthat are adjusted using a screwdriver. Flexibility in models offeredmakes the Proximity® liquid level switch applicable for manyrequirements that vary from system to system.

Paint StorageTank

HighAlarm

LowAlarm

FuelOil

Pump

Dip Tube Assembly

ElectricallyOperated

ValvePressurized

Tank

ToHigh-Low

TemperatureAlarm

Mercoid® DA Series

Temp.Control

BulbPressure

Well

Mercoid 215Level Control

LevelSwitch

LiquidLevel

Dip TubeAssembly

enhanced in the convenient top-mounted dip tube applicationdepicted, in which product does not touch the diaphragm. One ortwo switches in the housing are used to indicate point level of theliquid, or mixture, as it rises in the dip tube. Rising level causesstatic pressure in the dip tube to increase, depressing thediaphragm and causing repelling magnets on the diaphragm andswitch arm(s) to actuate the switch(es) in the sealed housing.Falling level causes decreased static pressure in the dip tube anddecreased repelling magnetic force(s). This allows spring forceto overcome the magnetic force and return both the diaphragmand switch arm(s) to original positions. The S-D™ model isapplicable for point levels up to 48 in. w.c. Thumbscrews in thehousing allow simple adjustment of set points in the field. Bothhigh and low levels can be monitored with the Proximity® S-D™model. A variety of diaphragm materials make this a flexibleproduct applicable in many industries.

The magnetic coupling providescomplete protection againstenvironmental damage to theprecision switch(es) in thehousing. Protection is further

pg 42 12/11/03 9:02 AM Page 1

PumpMotorControl

Pump

FromDrains

B-190Level Control

This large commercial automatic washing machine requirescontrol of the wash and rinse water levels independent of thetimed flow of inlet water which can vary with pressure. A Dwyerdifferential pressure switch is specified to sense the pressuredeveloped by the head of water required for proper washeroperation. The switch activates the appropriate valves to achievethe exact water level required each time. Sensing lines must bearranged to trap air on the fill cycle and drain completely witheach completed cycle of the machine, or else they must bepurged with instrument air.

liqu

id/c

on

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43

Supply

Series PLS PaddleLevel Switch

Discharge

Series PLS PaddleLevel Switch

Many fast-food restaurants utilize liquid carbon dioxide as thesource for pressurized CO2 gas for dispensing soft drinks.Liquid CO2 requires less storage space and avoids movingheavy compressed gas tanks in and out of the building. Thestorage tank also requires less frequent servicing which can bedone from outside the building without interrupting operations.A Capsuhelic® differential pressure gage with its 500 psi ratedoperating pressure can safely handle the vapor pressure in thetank and indicate the level of the tank contents by monitoringthe difference in pressure between the top and bottom of theinsulated tank. The gage can be calibrated in empty-full incre-ments, inches or gallons as desired. The high pressure (tankbottom) sensing line is run along the warm surface of the outerinsulating housing to insure the liquid CO2 is vaporized in thesensing line, keeping the cryogenic liquid from reaching thegage. Not all the piping and valving is illustrated in this simpli-fied diagram and the system does include an over-pressurerelief valve for safety reasons.

level

The supply of grain pneumatically conveyed to this dispensinghopper is controlled by two Proximity® Series PLS paddle levelswitches. When the grain level falls to the low limit switch, thesupply is turned on until the hopper fills to the level of the highlimit switch which turns off the supply. Since grain dust is explo-sive, the explosion-proof Series PLS provides the required safe-ty protection. The PLS is a paddle level switch and is not affect-ed by the varying pressure in the hopper due to the cycling ofthe pneumatic conveying system.

Industrial sumps and other underground tanks are ideal appli-cations for top-mounted Mercoid® displacer type level controls.Easily installed, these controls use porcelain displacers that donot float on the surface of liquids, but are suspended on a coilspring and cable. As the liquid in the tank reaches the level ofthe upper displacers, their weight decreases by an amountequal to the liquid displaced, allowing the spring to move thecable upward, actuating the switch and the pump is turned on.As the liquid level falls below the upper displacers they moveonly a small amount, staying within the switch deadband untilthe liquid level falls to the center of the bottom displacer. At thispoint the switch is deactivated stopping the pump. The pumpwill remain deactivated until the water level rises to the upperdisplacers, repeating the cycle. The displacers are not affectedby turbulence, pressure or chemicals and are excellent for tankswith viscous or dirty liquids. The level differential is easilyadjusted by repositioning of the displacers on the 316SS cable.

Grain hopper level controlledby Series PLSPaddleLevelSwitch.

Differential pressure switch controls washer waterlevel.

Mercoid® displacertype level control isideal for controllingindustrial sump pumps. Fast-food restaurant liquid CO2 tank uses

gage as level indicator.

Safety Gate

Washer

SlidingDoors

Control Section DifferentialPressureSwitch

Fill Pipe

LO

HI

Filling Box

Capsuhelic® Gage

LevelSensingLines

PressureTank

InsulatingHousing

ReliefValve

CO2 to Beverage Dispenser

pg 43 12/11/03 9:03 AM Page 1

Liquid nitrogen forms the basis for a simple, reliable and effec-tive in-transit refrigeration system. When sprayed under its owngas pressure from the tank into the cargo space, the nitrogenchanges from a liquid to a gas and absorbs heat. Depending onthe tank vapor pressure, a Magnehelic® differential pressuregage with a medium or high pressure option or a DwyerCapsuhelic® gage measures the level of liquid nitrogen in theclosed tank. The high pressure tap samples hydrostatic pres-sure of the fluid at the tank bottom and the low pressure tapsamples the gas pressure at the top of the tank. Normally, thesmall amount of liquid nitrogen entering the sensing line will bevaporized by ambient heat, thus purging the sensing line. Thedifferential pressure is a function of the liquid nitrogen level. Thegage can be calibrated for a given tank size in either percent oftank capacity or in pounds of liquid nitrogen. The Magnehelic®

gage has proved it toughness by operating reliably in this over-the-road application for periods exceeding ten years.

HI

Magnehelic® Gage

LO

Liquid Nitrogen Tank

RefrigeratedTrailer

co

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44

The liquid in this reservoir is maintained at a constant level bymeans of the motor actuated valve controlled by the pressuresignal from a Dwyer Series 607 differential pressure transduc-er. The air pressure required to purge the dip tube of liquid isequal to the reservoir depth expressed in inches of water aftertaking into account the specific gravity of the liquid. Any changein reservoir level results in a proportional change in output cur-rent from the transducer which, when fed back through thecontrol circuit, adjusts the valve to either increase or decreasethe fill pipe flow to maintain the desired level.

level

When used with a compatible liquid, a Dwyer Capsuhelic® differential pressure gage serves as a simple liquidlevel indicator. With the high pressure port connected to a tap atthe bottom of the tank and the low pressure port vented to theatmosphere, the oil level can be read as a function of the head withdirect calibration in feet or inches, taking into account the specificgravity of the liquid. If the tank is closed, as indicated by the dot-ted lines, the differential pressure produced by the head (andmeasured by having the low pressure port connected to a tap at thetop of the tank) will yield the same results regardless of total tankpressure. As the gage will indicate head from its location to thelevel in the tank, the gage must be mounted at the same elevationas the bottom of the tank or some datum line. A minor amount ofelevation correction can be made with the zero adjust screw. Abrass housing is available for water level applications.

Mercoid® model 123 level controls provide highand low alarm on large de-aerator tank.

Differential pressure gage measures level of liquidnitrogen in tank.

Dwyer gage indicates liquid level directly.

Transducer maintains constant liquid level in reser-voir by controlling motor-actuated fill valve.

Liquid level in the external piping equals level in the tank. Whenlevel rises to high limit, float in upper model 123 is lifted, actu-ating switch to sound high level alarm. When level drops to lowlimit, lower model 123 sounds low level alarm.

Water In

VentSteam In

123

123Water Out

Control Unit

MotorActuatedValve

Fill Pipe

Liquid

Series 607Transmitter

Drain Pipe

Reservoir

Air Supply

HI

Flowmeter& RegulatorOil Tank

Capsuhelic®

Gage

LOHI

pg 44 12/11/03 9:06 AM Page 1

liqu

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on

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level/temperature

Many types of heavy industrial equipment use a liquid coolingsystem for the motor. A vibratory trench roller is a machinethat compacts sub-bases for roads, parking lots, etc., and is anexample of the type of equipment that would utilize this system.This machine incorporates a radiator cooling system. In thesystem, cooling liquid circulates through the engine preventingit from over heating. As the engine is cooled the cooling fluidheats up. The fluid returns to the radiator to cool down beforebeing circulated through again. If there is not enough coolingfluid in the system the engine will not be cooled enough anddamage will occur. A W. E. Anderson® Series OLS optical levelswitch is installed as a low level alarm. The level alarm is sig-naled by the OLS before the cooling fluid gets to a critical lowlevel, warning the operator of the problem. The OLS uses anoptical detection system superior for this application as floatcontrols may trip from machine vibration. Also the compactinsertion length is ideal for a small radiator.

W.E. Anderson®

Series OLS indicates level inheavy equipmentradiator.

Model OLSOptical Level

Switch

Standard float switches require at least an inch of liquid toattain enough buoyancy to switch. This can be a problem inapplications where low level sensing is required. The hat-shaped design of Dwyer’s F7-LL provides necessary buoyancyfor switching in only 5/8˝ of water. This is essential for air con-ditioner drip pans, low level sumps, and drains. The F7-LL isalso ideal for low alarms, where running the process dry canresult in catastrophic failure.

SeriesF7-LL

Low level float switch enables sensing in air conditioner drip pans and other shallow levelapplications.To meet various tank level measuring needs, Dwyer offers cus-

tom-configured products built to customer specifications thatprovide visual indication, continuous level measurement, andmultiple point level measurement. Series VR or MVR View-Rite Level Indicators are a safe way to keep the process isolat-ed while providing true visible indication. Unlike sight glass-es, which can crack or break, View-Rite Indicators contain liq-uids entirely within their stainless steel enclosure. For contin-uous level measurement needs, the Series CLT uses reedswitch technology to offer a more economical solution thanexpensive ultrasonic, submersible or RT transmitters. Lastly,the Series F7-MQ can be used in virtually any tank to indicatehigh and low alarms or to control pumps and valves.

High HighAlarm/SystemShutdown

High Alarm

Low Alarm

Low LowAlarm/SystemShutdown

Series CLT Series F7-MQ

Series VR

Custom levelsensing devicesare built tomeet each customer’s specific requirements,providing visualindication, continuousmeasurement,and point levelcontrol.

Form, fill and seal machine control simplified withdual zone control.

Form, fill and seal machines traditionally have used separatecontrols to handle the temperature control requirement for theside and top/bottom seal bars. The Love Controls 32DZ withLove 5000 Series thermocouples allows for a single small for-mat (1/32 DIN) control to handle both zones, simplifying wiringand reducing panel costs.The 32DZ can switch small resistive loads directly or, when usedwith the Love 2981 Series solid state relays (not shown), canswitch larger loads.

Control Panel

PackageMaterialFeed Roll

Fill Funnel

Side SealHeater Bars*

Top/BottomSeal Bars*

SealedPacket(example: Bag of Chips)

Series 32DZControl

* Each sealer ba r set has heaters & a Love Thermocouple

pg 45 12/11/03 9:08 AM Page 1

In bioscience laboratories, the preferred methods of tempera-ture control for experiments are heated water baths. There areexperiments where water cannot be used, so the next feasibleoption is to send temperature controlled air to the experimentsite. In order to use temperature controlled air, an air heater isneeded. Within this product, a Dwyer temperature controller isused for accurate and responsive temperature control. TheDwyer controller can adapt to a different environment throughdifferent operating modes such as SELF-TUNE® or manual PIDadjustments, or preset PID responses.

Dwy erCon troller

Air Flow(To Heater)

Air Flow(To Chamb er)

Sensor

Hea ter Power

PV

SERIES 2600

S V

°F

°C

REM

%

HOLD

AL2AL1

SP1

SP2

MAN

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46

When storing food or other perishables in chillers or displaycases, temperature must be carefully regulated to ensure theproducts remain fresh. If the storage area rises above the crit-ical preservation temperature, products can have their shelf lifedramatically shortened or be spoiled altogether. A DwyerSeries TS Digital Temperature Switch will prevent these scenar-ios by monitoring temperature and activating refrigeration anddefrost cycles to ensure the storage temperature stays withinsafe limits.

temperature

For most wires, removing the insulation is easy, but for mag-netic and enamel wires, removing the insulation is very difficult.One way to easily remove the insulation of the magnetic orenamel wire is to dip them in a solution of molten fused salts.The salts are heated to a temperature high enough to melt thesalts into a liquid, but not deteriorate them. This process usesa Dwyer feedback temperature controller. The Dwyer controllerallows the operator to input a desired temperature and maintainthat temperature accurately. The Dwyer controller will alsoretain the input temperature after the power is disconnected.

Dwyer controllers used within heater controllers.

Dwyer controllers involved in insulation removal.Series TS Digital Temperature Switches regulatetemperature in chillers and display cases.

Chillers & Display CasesSeries TS

DigitalTemperature

Switches

PV

Strip PotDwy er Con troller

Con trol Unit

Power

SERIES 2600

S V

°F

°C

REM

%

HOLD

AL2AL1

SP1

SP2

MAN

Environmental Chamber

Series 32DZControl

Inside: Love RTDDwyer 657C-1 RH Transmitter

Environmental chambers have traditionally used separate con-trols to handle the temperature and relative humidity controltasks. The Love Controls 32DZ dual zone control with Love5000 Series RTD and Dwyer Series 657 Humidity transmittercontrols both parameters in a single small format (1/32 DIN)control to handle both zones, simplifying wiring and reducingpanel costs.The 32DZ can switch small resistive loads directly or, when usedwith Love 2981 Series solid state relays (not shown), can switchlarger loads. For inductive loads (solenoids, motor starters, etc.) use theinternal relays of the 32DZ to drive external contactors such asthe Love 2481 Series.

Environmental chamber control simplified with dialzone control.

pg 46 12/11/03 9:10 AM Page 1

Packaging of condiments require the sealing bars to be heatedto a temperature hot enough to seal the packages, but notdestroy the packaging material. The heat on the sealing barsneeds to be controlled to ensure the heat does not becomeexcessive. Dwyer controllers are used in this process to accu-rately control the heat on the sealing bars. The sensors from theDwyer controllers are placed on the sealing bars to ensure accu-rate temperature readings. Should the heat become excessive,an alarm light on the controller notifies the operator of theimpending conditions.

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47

M 51

Duct

Air InAir Out

The self-acting temperature control valve features a self-con-tained valve, controller, and sealed thermal system in one com-pact package providing installation economy and long-termreliability. This package eliminates the temperature controllerrequired with standard control valves. The dispensing applica-tion shown includes a 36R valve that opens when the tempera-ture in the hot water tank decreases allowing the steam to heatthe water and bring the temperature up to a required set point,at which point the valve will close. A valve that closes on tem-perature rise (direct acting) would be required for this applica-tion. The W.E. Anderson® Hi-Flow™ quick-opening, doubleseated valve enables fast response for improved process con-trol in this application. If your application requires valve to openon temperature rise, then a reverse acting 36R is also offered.

temperature

Hot air from a dryer flows past the Mercoid® Model M-51 ducttemperature switch. If the temperature reaches a high set point,the bi-metal element rotates, actuating the switch to shut downthe dryer. The unit will not re-start until the Model M-51 manu-al reset is actuated. The Model M-51 is mounted in a special wellto prevent fouling by textile particles.

Accurate control of temperature and epoxy resin flow is impor-tant during resin transfer molding. For the epoxy resin to havean even and thorough flow, the resin must be at a temperaturehigh enough to allow it to flow, yet not burn the resin. With thehelp of a Dwyer controller, the temperature of the resin is accu-rately controlled under different conditions through the differ-ent PID operating modes. Another Dwyer controller, with a flowtransducer, is used in this process to control the flow of theepoxy resin. The Dwyer controller provides information on thetemperature and flow rate to the computer through an RS485serial communication option.

Mercoid® Model M-51R duct temperature switchprovides high temperature cut-off on textile dryingunit. Dwyer controllers used in the packaging of

condiments.

Resin transfer molding.

Regulating process temperature using W.E.Anderson® self-acting temperature control valve.

Dwy er Con troller

Con trols

Fill HeadAssembly

Con dimentPackag ing

Oper ato r InterfaceMachine Con trol

PV

SERIES 2500

S V

°F

°C

AL

SP

Self-ActingTemperature Controller

Steam Supply

SteamStrainer Unions

Condensate Outlet

RecommendedBulb Location

Hot Water Outlet

Dwy er Con troller s

VacuumHose

Con trols

Epoxy ResinMolding Machine

PV

SERIES 2600

S V

°F

°C

REM

%

HOLD

AL2AL1

SP1

SP2

MAN

pg 47 12/11/03 9:13 AM Page 1

Condensate Return Line

Vent

FeedwaterPump

Hi-Flow™Valve

CondensateReturn Tank

WaterLevel

FeedwaterLine

Boiler

LevelControl

48

temperature/valvesc

on

tro

l

Process temperature control using pneumatic Hi-Flow™ control valves.

Pneumatic Hi-Flow™ control valves provide excellent controlwith high flow, wide rangeability and tight shutoff capabilities.The dispensing application shown uses a Lin-E-Aire® pneumaticactuator, operating off standard 3-15 psi control air signals, anda Hi-Flow™ linear control valve that apportions steam or waterto a user process. The valve regulates cooling water or steamflow depending on the process requirement resident in the tem-perature controller program. This package can be provided witha Precisor® positioner and Proximity® position transmitter whichprovides an excellent process control application problem solu-tion.

Pump

Water or SteamAir Supply

I/P

OverpressureRelief Valve

ControlValve Temperature

Sensor

TemperatureController

Process

HeatExchanger

Hi-Flow™ pneumatic control valve, available with bronze or 316stainless steel body and 316 stainless steel trim, provides supe-rior corrosion resistance and durability. A lined Plast-A-Vane®

butterfly valve with pneumatic actuator could also be used toprovide excellent corrosion resistant characteristics. Both typesof valves yield superb flow characteristics and enhanced shut-off capabilities ensuring years of trouble-free, reliable operation.In the application shown, throttle action of the High-Flow™ lin-ear globe valve, or the rotary movement of the Plast-A-Vane®

quarter-turn butterfly valve, is used to regulate the flow of acidsolution into a food/dairy process to accurately control the pHof the system.

Regulating pH for food and dairy applicationsusing linear or rotary pneumatic control valves.

Acid Solution I/P pH Controller

Pump Relief Valve ControlValve

pH Sensor

Process

Maintaining the proper water level in a boiler is critical to itsproper operation. Too much water and water can get into thesteam lines, while too little water and the boiler can over heat.Both conditions can lead to damage of the boiler or heating sys-tem. Feedwater going into the boiler needs to be controlled tomaintain the proper boiler water level. The W. E. Anderson® Hi-Flow™ globe valve is used to control the flow of the feedwater tomaintain that proper water level. The control valve is used witha proportioning electric actuator that is directly controlled by alevel transmitter in the boiler. As the water level drops in theboiler the valve lets in more water and as water level increasesthe valve lets in less water. Thus proper water levels are alwaysmaintained keeping the boiler operating properly and efficiently.

W.E. Anderson® Series Hi-Flow™ valves are used forflow control of water into industrial boilers.

The SAE valve is used as a shut off valve on the hydraulic sys-tem on injection molding machines. Normally the valve is in theopen position during operation. When the hydraulic pumpneeds servicing the valve is closed to isolate the hydraulicreservoir to prevent loss of hydraulic fluid. The SAE valve hasconnections conforming to SAE J518, which is a four screwsplit flange port. An o-ring seal is utilized in the connectiondesign that reduces leaks associated with tapered thread andgasket type seals. The connection allows for the reduction ofunneeded adapters and has a low profile reducing spacerequirements.

W.E. Anderson® Series SAE Butterfly Valves are uti-lized on hydraulic reservoirs on injection moldingmachines.

Series SAEButterfly Valves

pg 48 12/11/03 9:19 AM Page 1

co

ntro

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49

valves

Proximity® Mark Series position indicator is utilized in valveautomation packages in harsh environments. The Mark Seriesmounts onto the top of rotary valve actuators and connects tothe actuator shaft or attaches to the shaft of a linear valve forindicating valve position. Standard with the Mark Series is visu-al position indication with “OPEN”, “CLOSED”, and degree posi-tion status. The Mark Series is available with continuous posi-tion retransmission with a 4 to 20 mA output and up to sixadjustable position indication switches for remote indication ofvalve status. Remote status transmitter is used for indication ofexact valve position and switches provide discrete indication ofvalve open and closed status in the control room. The MarkSeries is perfect for this application because of the 316 SSenclosure that withstands the sea spray environment, and thepatented magnetic drive mechanism that completely seals theswitch cavity from the environment.

For the convenience of the control valve user, a compact,adjustable stainless steel visual indicator is provided on all direct-drive Proximity® position indicating switches and transmitters.These industrial switches are commonly mounted on quarter-turnpneumatic actuators and valves. A magnetic design provides max-imum safety by allowing complete sealing of the switch cavity.Over 2000 specific applications are covered with an extensive lineof mounting kits built for individual valve and actuator brands andmodel numbers. As the valve and actuator is cycled, the input shaftof the position indicator rotates, causing a stainless steel cylinderto rotate inside a second stainless steel cylinder with windows.When the valve is open the word “OPEN” appears in the two win-dows located 180° apart. The compact and durable visual indicatordisplays discrete endpoints (OPEN or CLOSED) as well as scaleddegrees (0-90). LED and flow path outputs are available options.Up to 3 conduit entrances allow utilization of this flexible indicatoras a junction box for additional convenience as well as material andlabor cost reduction to the user.

When receiver pressure rises to a predetermined setting, thetotal closure valve closes automatically, blocking the air inletand preventing air from entering the compressor. After allcompressed air is evacuated from the cylinders and intercool-er, the solenoid control valve on the high-pressure cylinder isopened to atmosphere allowing that minute amount of airremaining in the high-pressure cylinder to be exhausted. Thecompressor is now operating in a vacuum with minimal loss-es due only to mechanical friction in bearings and on slidingsurfaces. Minimal horsepower is needed to overcome themechanical losses.

Quick response Hi-Flow™ valves control waterflow in cooling process.

Proximity® Mark Series valve position indicator isperfect for valve position indication on offshore oilrigs.

Compressor unloading using W.E. Anderson®

Plast-A-Vane® butterfly valve.

Visual valve position indication with Proximity®

explosion-proof position indicators provides convenience and enhanced safety in valve monitoring.

Dependable W.E. Anderson® Hi-Flow™ control valves with Lin-E-Aire® air-to-raise actuators combine to provide unsurpassedwater flow management. This retort system employs the Hi-Flow™ valve because of its excellent control capabilities,which are necessary for this application. After the cookingprocess, the valve is opened slowly. Once the desired temper-ature has been reached, the supply is shut off and any addi-tional cooling is done by use of the hand valve.

AirSupply

CheckValve

Retort

HandValve

60 psiWater Supply

OptionalCooling EnableSolenoid Valve

PositionIndicator

Actuator

Control Valve

Local orRemoteElectricalPosition

Indication

Control Panel

Light AlarmDiscrete Electrical

ContinuousElectrical (4-20mA)

Water Outlet

Aftercooler

Air IntakeFilter

WaterInlet

Separator

AirReceiver

Air Outlet

Trap

PositionIndicator

Actuator

Control Valve

LocalVisual

Indication

Open Closed

Discrete Visual

Continuous Visual

0° 30° 45° 60°90°

pg 49 12/11/03 9:20 AM Page 1

pro

ce

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50

valves/miscellaneous

Proximity® Series QV position indicator is utilized in valve automa-tion package. Quarter turn valves such as ball and butterfly valvesare often automated with pneumatic or electric actuators. Theactuator connects to the shaft of the valve and rotates it. Usuallythe actuator has a shaft of its own that comes out of the top androtates as the actuator rotates the valve. The QV mounts onto thetop of the actuator and connects to this actuator shaft for indicat-ing valve position. When the valve is open or closed, the corre-sponding word “OPEN” or “CLOSED” appears in four windows 90°apart. The visual indicator also includes degree position indicationof 0 to 90°. The QV is compact yet the visual indictor is large andeasy to view from a distance. Adjustable position indicationswitches are available to remotely indicate if the valve is fullyopened or closed. The QV assures proper operation of the valveand indicates problems so they can quickly be addressed.

Proximity® Series QV indicates valve position locally and remotely.

PositionIndicator

Actuator

Control Valve

LocalVisual

Indication

Open Closed

Discrete Visual

Continuous Visual

0° 30° 45° 60°90°

The Dwyer Series 450 Carbon Monoxide Monitor is the idealhandheld instrument used by Building Inspectors and BuildingMaintenance Supervisors for inspecting indoor carbon monox-ide (CO) levels. To determine if a building's indoor air meetssafe allowable levels set by ASHRAE, an inspector can easilywalk through a building with the 450 to see if the building meetscode. With the 450's peak CO recording feature, the user canquickly determine if any part of the facility surpassed the safeallowable level. An audible and visual light respond when userprogrammed limits are exceeded. The 450 CO Monitor is alsoused by workers in tunnels, mines and sewers.

When transporting temperature-sensitive products such asmeat, produce, beer and wine over long distances, it is neces-sary to verify that the storage compartment has not exceededthe critical preservation temperature at any time. Dwyer BDLButton Dataloggers offer a low cost way to measure and recordstorage temperatures throughout transport. By placing several“buttons” throughout the storage compartment and setting anappropriate measurement interval, transportation services canretrieve data at the completion of delivery to assure their cus-tomers of adequate preservation temperatures.

Button Datalogger monitors food and beveragetemperature in refrigerated transport vehicles.

Quickly determine a building’s carbon monoxidelevels with Carbon Monoxide Monitor

Series 450Carbon MonoxideMonitor

Series BDLButton Data

Logger10¢

To ensure efficient utilization of cold water in HVAC systems,W.E. Anderson® Plast-A-Vane® 3-way butterfly valves are calledupon to modulate flow. This common “water-side economizer”allows water from the plate heat exchanger to be diverteddirectly to the cooling tower if the temperature is cool enough,instead of coming directly from the condenser on the chiller.

Water-side Economizer System includes Plast-A-Vane® 3-way butterfly valve for accurate controlof flow.

Tower Exhauster

Fan

Cooling Tower Chiller

PlateHeat

Exchange

pg 50 12/11/03 9:22 AM Page 1

an

alyze

/me

asu

re/c

on

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51

Data acquisition is an essential tool for process monitoring andsystem evaluation. It is also an integral factor in troubleshoot-ing and malfunction testing. Dwyer’s DL8 Process Dataloggerenables users to acquire data from up to seven transmitters orother instruments by accepting industry standard analog inputs.With easy-to-use software, plots of the instruments’ perform-ance can be conveniently uploaded and viewed graphically ornumerically on a PC or laptop. Additionally, the DL8 can moni-tor data in real time for instant results or acquire data over auser-defined interval for long-term monitoring.

For testing transmitters and other process loop components,Dwyer’s LC21 Smart Loop Calibrator is the ideal instrument.The LC21 can be used to simulate any two of the three basiccomponents of an analog process loop, the transmitter, indi-cator, or power supply. To perform calibration tests on anindicator, panel meter, or PLC, the LC21 will simulate a trans-mitter by sourcing an analog output signal while providing theloop power supply. To perform calibration tests on a transmit-ter, the Smart Loop Calibrator will simulate the indicator whileproviding the power supply. The end result is a compact,portable, easy-to-use calibration tool for analog systems.

Combustion analyzer maximize boiler efficiencywhile monitoring harmful products of combustion.

Dataloggers simplify performance assessment formultiple transmitters and other measurementdevices.

Perform field calibration of transmitters and con-trol systems.

There are several critical factors in attaining efficient combus-tion for boilers and other combustors. Monitoring the temper-ature of combustion and minimizing the amount of excess air inthe system are undoubtedly essential steps. A Dwyer 1207-NOX

Flue Gas Analyzer can break down the products of combustion,giving an accurate volumetric composition of harmful NOX com-pounds, O2, CO2, and CO. Additionally, the 1207-NOX will mon-itor differential temperature, excess air and poison index.Results can be easily viewed on screen or uploaded to a PC viathe user-friendly software.

Preheater Boiler

Feedwater Steam

CH4

Air

Combustion gas

TemperatureTransmitter

FlowTransmitter Air Velocity

Transmitter

LevelTransmitter

PressureTransmitter

Series DL8

Transmitter

Model LC21Smart LoopCalibrator

miscellaneous

Series 485Digital Hygrometer

The Dwyer 485 Handheld Digital Hygrometer is a simple,portable device for quickly measuring humidity and temper-ature levels in ambient air. The dew point and wet-bulb tem-perature readings are derived from relative humidity andtemperature measurements. The 485 is often used in agri-cultural applications where proper humidity and temperaturelevels are critical in plant or animal well being.

Quickly measure humidity and temperature lev-els in ambient air.

pg 51 12/11/03 9:23 AM Page 1

refe

ren

ce

52

referenceAREA OF CIRCLES IN FT2

Diam.in

Inches

Diam.in

Inches

AREASquare

Feet

AREASquare

Feet

111⁄22

21⁄23

31⁄24

41⁄25

51⁄26

61⁄27

71⁄28

81⁄29

91⁄21011121314151617181920212223242526272829

.0054

.0123

.0218

.0341

.0491

.0668

.0873

.1105

.1364

.1650

.1964

.2305

.2673

.3068

.3491

.3940

.4418

.4923

.5454

.6600

.7854

.92181.0691.2271.3961.5761.7671.9692.1822.4052.6402.8853.1423.4093.6873.9764.2764.587

3031323334353637383940414243444546474849505152535456586062646668707274767880

4.9095.2415.5855.9406.3056.6117.0697.4677.8768.2968.7279.1689.62110.0810.5611.0411.5412.0512.5713.1013.6414.1914.7515.3215.9017.1018.3519.6320.9722.3423.7625.2226.7328.2729.8731.5033.1834.91

Mercury at 0°C (32°F)

ALTITUDE PRESSURE TABLE

Altitudein feet

InMillimetersof Mercury

Inchesof Mercury

-1,0000

1,0002,0003,0004,0005,0006,0007,0008,0009,000

10,00015,00020,00025,00030,00035,00040,00045,00050,000

31.0229.92128.8627.8226.8125.8424.8923.9823.0922.2221.3820.5816.8813.7511.108.887.045.544.363.436

787.9760.0732.9706.6681.1656.3632.3609.0586.4564.4543.2522.6428.8349.1281.9225.6178.7140.7110.8

87.30

(BASED ON 68°F AND 14.7 LBS. ABS.)

SPECIFIC GRAVITIES OF GASES

ACETYLENEAIRAMMONIAARGONBUTANE-NBUTANE-ISOCARBON DIOXIDECARBON MONOXIDECHLORINEETHANE HELIUMHYDROGENMETHANENATURAL GAS

NITRIC OXIDENITROGENNITROUS OXIDEOXYGENPROPANESULPHUR DIOXIDE

C2H2

. . . . . . .

NH3

AC4H40

(CH)3)2CH CH3

CO2

COCL2

C2H6

HeH2

CH4

. . . . . .

NON2

N2002

C3H8

SO2

.8971.000.587

1.3782.3901.9901.517.966

2.4521.035.138.070.553.665

(Approx. Avg.)

1.035.966

1.5181.1031.5502.209

VOLUME EQUIVALENTS

1 CU. FT. = 1728 Cu. In.7.481 Gal. (U.S.)28.317 Liters28.317 Cu. Cm.

1 GAL. (U.S.) = 231 Cu. In..1337 Cu. Ft.3.785 Liters3785 Cu. Cm.

1 LITER = .0353 Cu. Ft..2642 Gal. (U.S.)1000 Cu. Cm.

FLOW EQUIVALENTS

1 Cu. Ft./Hr. 1 Cu. Ft./Min.

.0166 Cu. Ft./Min.

.4719 LPM28.316 LPH

471.947 CC/Min.28317 CC/Hr..1247 Gal/Min.7.481 Gal/Hr.

60 Cu. Ft./Hr.28.316 LPM

1699 LPH28317 CC/Min.

1,699,011 CC/Hr.7.481 Gal/Min.

448.831 Gal/Hr.

1 CC/Min.

60 CC/Hr..000035 Cu. Ft./Min.

.0021 Cu. Ft./Hr..001 LPM.06 LPH

.00026 Gal/Min..0159 Gal/Hr.

1 CC/Hr.

.0167 CC/Min..0000005 Cu. Ft./Min.

.00003 Cu. Ft./Hr..000017 LPM

.001 LPH.000004 Gal/Min..00026 Gal/Hr.

1 LPH

.0166 LPM.00059 Cu. Ft./Min.

.035 Cu. Ft./Hr.16.667 CC/Min.

1000 CC/Hr..004 Gal/Min..264 Gal/Hr.

1 LPM

60 LPH.035 Cu. Ft./Min.

2.1189 Cu. Ft./Hr.1000 CC/Min.

60,002 CC/Hr..264 Gal/Min.

15.851 Gal/Hr.

1 Gal/Min.

60 Gal/Hr..1337 Cu. Ft./Min.8.021 Cu. Ft./Hr.3.785 LPM

227.118 LPH3,785.412 CC/Min.

227,125 CC/Hr.

1 Gal/Hr.

.0167 Gal/Min..002 Cu. Ft./Min.

.1337 Cu. Ft./Hr..063 LPM

3.785 LPH63.069 CC/Min.

3785 CC/Hr.

Liquid

AcetoneAlcohol, ethylAlcohol, methylAmmonia, saturatedBenzeneBrine (10% Na Cl)Carbolic acidCarbon disulfideCarbon tetrachlorideChloroformEtherFuel Oils

1235A5B6

Gas oilsGasolines

abc

GlycerineHeptane-nHexaneKeroseneMercuryMethyl acetateMethyl iodideMilk Naptha, petroleum etherNaptha, woodOils

CastorCoconutCotton seedCreosoteLinseed, boiledOlivePalmPeanut Sesame SeedSoy Bean

PentanePropylene glycolSAE 30 Lube OilSea WaterSodium chloride5%25%

Sodium hydroxide (caustic soda)20%30%40%Turpentine (spirits)Water

Specific Gravity

0.7920.7910.8100.6550.91.080.950 to 0.9651.2931.5951.4890.736

0.82 to 0.950.82 to 0.950.82 to 0.950.82 to 0.950.82 to 0.950.82 to 0.950.89

0.740.720.681.2600.6880.6640.82013.6000.932.281.028 to 1.0350.6650.848 to 0.810

0.9690.9250.9261.040 to 1.2000.9240.9180.9240.920.9230.924 to .928.6231.0380.91.025

1.0371.1961.19

1.221.331.430.8701.000

SPECIFIC GRAVITY OF LIQUID

pg 52 12/11/03 9:27 AM Page 1

Customer Service

Technical Support

Prompt Shipments

Website

Pressure Conversion Chartin/H2O

.1

.2

.4

.6

.81.023456789

101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899

100

P.S.I.

.0036

.0072

.0144

.0216

.0289

.0361

.0722

.1083

.1444

.1804

.2165

.2526

.2887

.3248

.3609

.3970

.4331

.4692

.5053

.5414

.5774

.6136

.6496

.6857

.7218

.7579

.7940

.8301

.8662

.9023

.9384

.97451.0101.0471.0831.1191.1551.1911.2271.2631.2991.3351.3711.4081.4441.4801.5161.5521.5881.6241.6601.6961.7321.7681.8041.8411.8771.9131.9491.9852.0212.0572.0932.1292.1652.2022.2382.2742.3102.3462.3822.4182.4542.4902.5262.5622.5982.6352.6712.7072.7432.7792.8152.8512.8872.9232.9592.9963.0323.0683.1043.1403.1763.2123.2483.2843.3203.3563.3923.4293.4563.5013.5373.5733.609

in/Hg

.0073

.0146

.0293

.0440

.0588

.0735

.1470

.2205

.2940

.3673

.4408

.5143

.5878

.6613

.7348

.8083

.8818

.95531.0291.1021.1761.2491.3221.3961.4701.5431.6161.6901.7641.8371.9101.9842.0562.1322.2052.2782.3522.4252.4982.5712.6452.7182.7912.8762.9403.0133.0863.1603.2333.3063.3783.4533.5263.6003.6733.7483.8223.8953.9684.0414.1154.1884.2614.3354.4084.4834.5564.6304.7034.7764.8504.9234.9965.0705.1435.2165.2905.3655.4385.5115.5855.6585.7315.8055.8785.9516.0246.1006.1736.2466.3206.3936.4666.4506.6136.6866.7606.8336.9066.9817.0557.1287.2017.2757.348

mm/H2O

2.5345.067

10.1315.2020.3425.4150.8176.22

101.62127.0152.4177.8203.2228.6254.0279.4304.8330.2355.6381.0406.4431.8457.2482.6508.0533.4558.8584.2609.6635.0660.4685.8710.8736.8762.2787.5812.8836.2863.5888.9914.2939.5964.9990.9

1016104210671092111811431168119412191244127012961321134613721397142214481473149815241550157516001626165116761702172717521778180318281854188019051930195619812006203220572082210821342159218422102265226022862311233623622387241324382464248925142540

mm/Hg

.1863

.3726

.74521.1181.4961.8683.7365.6047.4729.335

11.20313.07214.94016.80818.67620.54422.41224.28026.14828.01629.87931.75233.61635.48437.35239.2241.0942.9644.8246.6948.5650.4352.2654.1856.0457.9159.7761.6363.4965.3667.2269.0870.9572.8674.7276.5978.4580.3182.1884.0485.9087.7689.6391.4993.3595.2797.1398.99100.8102.7104.6106.4108.3110.2112.0113.9115.8117.7119.5121.4123.3125.1127.0128.8130.7132.6134.4136.4138.2140.1141.9143.8145.7147.5149.4151.2153.1155.0156.9158.8160.6162.5164.4166.2168.1169.9171.8173.7175.5177.4179.3181.2183.0184.9186.8

kg/cm2

.0002

.0005

.0010

.0015

.0020

.0025

.0051

.0076

.0102

.0127

.0152

.0178

.0203

.0228

.0254

.0279

.0304

.0330

.0355

.0381

.0406

.0431

.0457

.0482

.0507

.0533

.0558

.0584

.0609

.0634

.0660

.0685

.0710

.0736

.0761

.0787

.0812

.0837

.0862

.0888

.0913

.0938

.0964

.0990

.1015

.1040

.1066

.1091

.1116

.1142

.1167

.1192

.1218

.1243

.1268

.1294

.1320

.1345

.1370

.1395

.1421

.1146

.1471

.1497

.1522

.1548

.1573

.1599

.1624

.1649

.1674

.1700

.1725

.1750

.1776

.1801

.1826

.1852

.1878

.1903

.1928

.1954

.1979

.2004

.2030

.2055

.2080

.2106

.2131

.2157

.2182

.2207

.2233

.2258

.2283

.2309

.2334

.2359

.2384

.2410

.2436

.2461

.2486

.2512

.2537

bar

.0002

.0005

.0010

.0015

.0020

.0025

.0050

.0075

.0099

.0124

.0149

.0174

.0199

.0224

.0249

.0274

.0299

.0324

.0348

.0373

.0398

.0423

.0448

.0473

.0498

.0523

.0547

.0572

.0597

.0622

.0647

.0672

.0696

.0722

.0747

.0772

.0796

.0821

.0846

.0871

.0896

.0920

.0945

.0971

.0996

.1020

.1045

.1070

.1095

.1120

.1144

.1169

.1194

.1219

.1244

.1269

.1294

.1319

.1344

.1369

.1393

.1418

.1443

.1468

.1493

.1518

.1543

.1568

.1593

.1618

.1642

.1667

.1692

.1717

.1742

.1766

.1791

.1817

.1842

.1866

.1891

.1916

.1941

.1966

.1991

.2015

.2040

.2066

.2091

.2115

.2140

.2165

.2190

.2215

.2239

.2264

.2289

.2314

.2339

.2364

.2389

.2414

.2439

.2464

.2488

mbar

.2482

.4964

.99281.4891.9922.4894.9787.4679.956

12.4414.9317.4219.9022.3924.8827.3729.8632.3534.8437.3339.8142.3144.7947.2849.7752.2654.7457.2359.7262.2164.7067.1969.6472.1974.6777.1579.6382.1284.6087.0889.5692.0494.5397.0899.56

102.0104.5107.0109.5112.0114.5116.9119.4121.9124.4126.9129.4131.9134.4136.9139.3141.8144.3146.8149.3151.8154.3156.8159.3161.8164.2166.7169.2171.7174.2176.6179.1181.7184.2186.6189.1191.6194.1196.6199.1201.5204.0206.6209.1211.5214.0216.5219.0221.5223.9226.4228.9231.4233.9236.4238.9241.4243.9246.4248.8

Pa

24.8249.6499.28

148.9199.2248.9497.8746.7995.6

124414931742199022392488273729863235348437333981423144794728497752265474572359726221647067196964721974677715796382128460870889569204945397089956

102041045210701109491119711445116941194212190124381269312941131901343813686139341418214431146791492715182154301567915927161751642316672169201716817416176641791218168184161866418912191601940919657199052015320402206572090521153214012165021898221462239422642228902313923387236422389024138243872463524883

kPa

.0248

.0496

.0993

.1489

.1992

.2489

.4978

.7476

.99561.2441.4931.7421.9902.2392.4882.7372.9863.2353.4843.7333.9814.2314.4794.7284.9775.2265.4745.7235.9726.2216.4706.7196.9647.2197.4677.7157.9638.2128.4608.7088.9569.2049.4539.7089.956

10.2010.4510.7010.9511.2011.4411.6911.9412.1912.4412.6912.9413.1913.4413.6913.9314.1814.4314.6814.9315.1815.4315.6815.9316.1816.4216.6716.9217.1717.4217.6617.9118.1718.4218.6618.9119.1619.4119.6619.9020.1520.4020.6620.9021.1521.4021.6521.9022.1522.3922.6422.8923.1423.3923.6423.8924.1424.3924.6424.88

P.S.I.

1.01.11.21.31.41.51.61.71.81.92.02.12.22.32.42.52.62.72.82.93.03.13.23.33.43.53.63.73.83.94.04.14.24.34.44.54.64.74.84.95.05.15.25.35.45.55.65.75.85.96.06.16.26.36.46.56.66.76.86.97.07.17.27.37.47.57.67.88.08.28.48.68.89.09.29.49.69.8

10.011.012.013.014.014.715.016.017.018.019.020.021.022.023.024.025.0

in/H2O

27.7130.4533.2235.9838.7541.5244.2947.0649.8252.5955.3658.1360.9063.6766.4369.2071.9774.7477.5180.2783.0485.8188.5891.3594.1196.8899.65

102.4105.2108.0110.7113.5116.3119.0121.8124.6127.3130.1132.9135.6138.4141.2143.9146.7149.5152.2155.0157.8160.5163.3166.1168.8171.6174.4177.2179.9182.7185.5188.2191.0193.8196.5199.3202.1204.8207.6210.4215.9221.4227.0232.5238.0243.6249.1254.7260.2265.7271.3276.8304.5332.2359.8387.5406.9415.2442.9470.6498.2525.9553.6581.3609.0636.7664.3692.0

in/Hg

2.0362.2402.4432.6472.8503.0543.2583.4613.6653.6864.0724.2764.4794.6834.8865.0905.2945.4975.7015.9046.1086.3126.5156.7196.9227.1267.3307.5357.7377.9408.1448.3488.5518.7758.9589.1629.3669.5699.7739.976

10.1810.3810.5910.7910.9911.2011.4011.6011.8112.0112.2212.4212.6212.8313.0313.2313.4413.6413.8414.0514.2514.4614.6614.8615.0715.2715.4715.8816.2916.7017.1017.5117.9218.3218.7319.1419.5419.9520.3622.4024.4326.4728.5029.9330.5432.5834.6136.6536.6840.7242.7644.7946.8348.8650.90

mm/H2O

703.1773.4843.7914.0984.3

105511251195126613361406147615471617168717581828189819692039210921802250232023902461253126012672274228122883295330233094216432343304337534453515358636563726379738763973400840784148421842894359442945004570464047114781485149224992506251325203527353435484562557655906604761876328646866096750689070317734843791409843

103401055011250119501266013360140601477015470161701687017580

mm/Hg

51.7556.8962.0667.2372.4077.5782.7487.9293.0998.26

103.4108.6113.8118.9124.1129.3134.5139.6144.8150.0155.1160.3165.5170.7175.8181.0186.2191.3196.5201.7206.9212.0217.2222.4227.5232.7237.9243.1248.2253.4258.6263.7268.9274.1279.3284.4289.6294.8299.9305.1310.3315.5320.6325.8331.0336.1341.3346.5351.7356.8362.0367.2372.3377.5382.7387.9393.0403.4413.7424.1434.4444.7455.1465.4475.8486.1496.5506.8517.1568.9620.6672.3724.0760.2775.7827.4879.1930.9982.6

103410861138118912411293

kg/cm2

.0703

.0773

.0844

.0914

.0984

.1055

.1125

.1195

.1266

.1336

.1406

.1476

.1547

.1617

.1687

.1758

.1828

.1898

.1968

.2039

.2109

.2180

.2250

.2320

.2390

.2461

.2531

.2601

.2672

.2742

.2812

.2883

.2953

.3023

.3094

.3164

.3234

.3304

.3375

.3445

.3515

.3586

.3656

.3726

.3797

.3867

.3937

.4007

.4078

.4148

.4218

.4289

.4359

.4429

.4500

.4570

.4640

.4710

.4781

.4851

.4921

.4992

.5062

.5132

.5203

.5273

.5343

.5484

.5625

.5765

.5906

.6046

.6187

.6328

.6468

.6609

.6749

.6890

.7031

.7734

.8437

.9140

.98431.0331.0551.1251.1951.2651.3361.4061.4761.5471.6171.6871.758

bar

.0689

.0758

.0827

.0896

.0965

.1034

.1103

.1172

.1241

.1310

.1379

.1448

.1517

.1586

.1655

.1724

.1793

.1862

.1930

.1999

.2068

.2137

.2206

.2275

.2344

.2413

.2482

.2551

.2620

.2689

.2758

.2827

.2896

.2965

.3034

.3103

.3172

.3240

.3310

.3378

.3447

.3516

.3585

.3654

.3723

.3792

.3861

.3930

.3999

.4068

.4137

.4206

.4275

.4344

.4413

.4482

.4550

.4619

.4688

.4757

.4826

.4895

.4964

.5033

.5102

.5171

.5240

.5378

.5516

.5654

.5792

.5929

.6067

.6205

.6343

.6481

.6619

.6757

.6895

.7584

.8274

.8963

.96521.0141.0341.1031.1721.2411.3101.3791.4481.5171.5861.6551.724

mbar

68.9575.8482.7489.6396.52

103.4110.3117.2124.1131.0137.9144.8151.7158.6165.5172.4179.3186.2193.0199.9206.8213.7220.6227.5234.4241.3248.2255.1262.0268.9275.8282.7289.6296.5303.4310.3317.2324.0331.0337.8344.7351.6358.5365.4372.3379.2386.1393.0399.9406.8413.7420.6427.5434.4441.3448.2455.0461.9468.8475.7482.6489.5496.4503.3510.2517.1524.0537.8551.6565.4579.2592.9606.7620.5634.3648.1661.9675.7689.5758.4827.4896.3965.2

101410341103117212411310137914481517158616551724

Pa

68957584827489639652

103401103011720124101310013790144801517015860165501724017930186201930019990206802137022060227502344024130248202551026200268902758028270289602965030338310303172032400331003378034470351603585036540372303792038610393003999040680413704206042750434404413044820455004619046880475704826048950496405033051020517105240053780551605654057920592906067062050634306481066190675706895075840827409863096520

101400103400110300117200124100131000137900144800151700158600165500172400

kPa

6.8957.5848.2748.9639.652

10.3411.0311.7212.4113.1013.7914.4815.1715.8616.5517.2417.9318.6219.3019.9920.6821.3722.0622.7523.4424.1324.8225.5126.2026.8927.5828.2728.9629.6530.3431.0331.7232.4033.1033.7834.4735.1635.8536.5437.2337.9238.6139.3039.9940.6841.3742.0642.7543.4444.1344.8245.5046.1946.8847.5748.2648.9549.6450.3351.0251.7152.4053.7855.1656.5457.9259.2960.6762.0563.4364.8166.1967.5768.9575.8482.7489.6396.52

101.4103.4110.3117.2124.1131.0137.9144.8151.7158.6165.5172.4

CONVERSION P.S.I. x 27.71 = in. H2O P.S.I. x .0689 = barFACTORS P.S.I. x 2.036 = in. Hg P.S.I. x 68.95 = mbar

NOTE: P.S.I. x 703.1 = mm/H2O P.S.I. x 6895 = PaCONVERSION FACTORS P.S.I. x 51.75 = mm/Hg P.S.I. x 6.895 = kPaROUNDED P.S.I. x .0703 = kg/cm2

DDWYER INSTRUMENTS, INC.P.O. Box 373Michigan City, IN 46361-9986

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