NOx Analyzer - Automation Solutions Rosemount...NOx Analyzer Emerson Process Management Rosemount Analytical Inc. Process Analytic Division 1201 N. Main St. Orrville, OH 44667-0901

Instruction Manual748214-RMarch 2002

http://www.processanalytic.com

Model 951CNOx Analyzer

Emerson Process ManagementRosemount Analytical Inc.Process Analytic Division1201 N. Main St.Orrville, OH 44667-0901T (330) 682-9010F (330) 684-4434e-mail: [email protected]://www.processanalytic.com

ESSENTIAL INSTRUCTIONSREAD THIS PAGE BEFORE PROCEEDING!

Rosemount Analytical designs, manufactures and tests its products to meet many national andinternational standards. Because these instruments are sophisticated technical products, youMUST properly install, use, and maintain them to ensure they continue to operate within theirnormal specifications. The following instructions MUST be adhered to and integrated into yoursafety program when installing, using, and maintaining Rosemount Analytical products. Failure tofollow the proper instructions may cause any one of the following situations to occur: Loss of life;personal injury; property damage; damage to this instrument; and warranty invalidation.

• Read all instructions prior to installing, operating, and servicing the product.

• If you do not understand any of the instructions, contact your Rosemount Analytical repre-sentative for clarification.

• Follow all warnings, cautions, and instructions marked on and supplied with the product.

• Inform and educate your personnel in the proper installation, operation, and mainte-nance of the product.

• Install your equipment as specified in the Installation Instructions of the appropriate In-struction Manual and per applicable local and national codes. Connect all products to theproper electrical and pressure sources.

• To ensure proper performance, use qualified personnel to install, operate, update, program,and maintain the product.

• When replacement parts are required, ensure that qualified people use replacement partsspecified by Rosemount. Unauthorized parts and procedures can affect the product’s per-formance, place the safe operation of your process at risk, and VOID YOUR WARRANTY.Look-alike substitutions may result in fire, electrical hazards, or improper operation.

• Ensure that all equipment doors are closed and protective covers are in place, exceptwhen maintenance is being performed by qualified persons, to prevent electrical shockand personal injury.

The information contained in this document is subject to change without notice.

Teflon® is a registered trademark of E.I. duPont de Nemours and Co., Inc.Alconox is a registered trademark of Alconox, Inc.SNOOP® is a registered trademark of NUPRO Co.

Instruction Manual748214-R

March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Contents i

Model 951C

TABLE OF CONTENTS

PREFACE...........................................................................................................................................P-1Definitions ...........................................................................................................................................P-1Safety Summary .................................................................................................................................P-2General Precautions For Handling And Storing High Pressure Gas Cylinders .................................P-5Documentation....................................................................................................................................P-6Compliances .......................................................................................................................................P-6Condensed Startup And Calibration Procedure .................................................................................P-7

1.0 DESCRIPTION AND SPECIFICATIONS..............................................................................1-11-1 Overview................................................................................................................................1-11-2 Typical Applications...............................................................................................................1-11-3 Specifications – Lo Range.....................................................................................................1-21-4 Specifications – Hi Range .....................................................................................................1-3

2.0 INSTALLATION ....................................................................................................................2-12-1 Unpacking..............................................................................................................................2-12-2 Location .................................................................................................................................2-12-3 Voltage Requirements ...........................................................................................................2-12-4 Electrical Connections ...........................................................................................................2-1

a. Line Power Connections .................................................................................................2-1b. Potentiometric Recorder Connections ............................................................................2-3c. Current Recorder Connections .......................................................................................2-3

2-5 Gas Requirements.................................................................................................................2-4a. Air (U.S.P. Breathing Grade) ..........................................................................................2-4b. Span Gas ........................................................................................................................2-4

2-6 Sample Requirements ...........................................................................................................2-42-7 Gas Connections ...................................................................................................................2-42-8 Leak Test ...............................................................................................................................2-5

3.0 OPERATION .........................................................................................................................3-13-1 Front Panel Indicators and Controls......................................................................................3-1

a. Display ............................................................................................................................3-1b. Range Selection..............................................................................................................3-1c. Sample Pressure Gauge.................................................................................................3-1d. Ozone Pressure ..............................................................................................................3-1e. Zero and Span Potentiometers .......................................................................................3-2f. Ozone Interlock ...............................................................................................................3-2

3-2 Startup Procedure .................................................................................................................3-23-3 Calibration..............................................................................................................................3-5

a. Zero Calibration...............................................................................................................3-5b. Upscale Calibration.........................................................................................................3-5

3-4 Routine Operation .................................................................................................................3-53-5 Converter Temperature Adjustment Procedure ....................................................................3-53-6 Measurement of Converter Efficiency ...................................................................................3-73-7 Recommended Calibration Frequency..................................................................................3-8


ii Contents Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

4.0 THEORY................................................................................................................................4-14-1 Nitric Oxide Determination by Chemiluminescence Method .................................................4-14-2 Analyzer Flow System...........................................................................................................4-1

a. Flow of Sample, Standard Gas or Zero Gas to Reaction Chamber ...............................4-1b. Ozone Generation...........................................................................................................4-1

4-3 Signal Processing Electronics System ..................................................................................4-24-4 Analyzer Thermal System .....................................................................................................4-2

5.0 ROUTINE SERVICING..........................................................................................................5-15-1 System Checks and Adjustments..........................................................................................5-1

a. Display Fullscale Span Adjustment.................................................................................5-1b. Overall Sensitivity............................................................................................................5-1c. Ozone Output..................................................................................................................5-2d. Background Current ........................................................................................................5-2

5-2 Servicing Flow System ..........................................................................................................5-3a. Cleaning Sample Capillary..............................................................................................5-3b. Ozone Restrictor Fitting ..................................................................................................5-3

5-3 Photomultiplier Tube/Reaction Chamber ..............................................................................5-4a. Removal ..........................................................................................................................5-4b. Cleaning Reaction Chamber...........................................................................................5-4c. Photomultiplier Tube and Housing..................................................................................5-5d. Replacement of Photomultiplier Tube.............................................................................5-6

5-4 Ozone Generation System ....................................................................................................5-7a. Lamp/Housing Removal..................................................................................................5-7b. UV Lamp Replacement...................................................................................................5-7c. Power Supply Removal...................................................................................................5-8

5-5 Converter Assembly ..............................................................................................................5-95-6 Servicing Electronic Circuitry.................................................................................................5-105-7 Leaks .....................................................................................................................................5-10

6.0 REPLACEMENT PARTS......................................................................................................6-16-1 Matrix .....................................................................................................................................6-16-2 Circuit Board Replacement Policy.........................................................................................6-26-3 Replacement Parts ................................................................................................................6-2

a. Common Parts ................................................................................................................6-2b. Photomultiplier Assembly 654062...................................................................................6-4c. Converter Assembly 654070...........................................................................................6-5d. Temperature Control Assembly 654068 .........................................................................6-6

7.0 RETURN OF MATERIAL......................................................................................................7-17-1 Return Of Material .................................................................................................................7-17-2 Customer Service ..................................................................................................................7-17-3 Training..................................................................................................................................7-1


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Contents iii

Model 951C

LIST OF ILLUSTRATIONS

Figure 2-1. Power Supply Board Voltage Select Switches ...................................................... 2-2Figure 2-2. Temperature Control Board ................................................................................... 2-2Figure 2-3. Cable Gland........................................................................................................... 2-3Figure 2-4. Rear View of Model 951C (cover removed) .......................................................... 2-3Figure 3-1. Model 951C Controls, Indicators and Adjustments ............................................... 3-1Figure 3-2. Signal Board .......................................................................................................... 3-3Figure 3-3. Power Supply Board .............................................................................................. 3-4Figure 4-1. Analyzer Signal Conditioning Circuit ..................................................................... 4-3Figure 4-2. Analyzer Thermal System...................................................................................... 4-3Figure 6-1. Major Assemblies of the Model 951C.................................................................... 6-3Figure 6-2. Photomultiplier Housing Assembly ........................................................................ 6-4Figure 6-3. Converter Assembly .............................................................................................. 6-5Figure 6-4. Case Heater Temperature Control Assembly........................................................ 6-6

LIST OF TABLES

Table 3-1. Resistance of Converter Temperature Sensor vs. Temperature........................... 3-6

DRAWINGS (LOCATED IN REAR OF MANUAL)

654063 Installation Drawing654090 Flow Diagram, Lo Range654093 Flow Diagram, Hi Range


iv Contents Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-1

Model 951C

PREFACE

The purpose of this manual is to provide information concerning the components,functions, installation and maintenance of the 951C NOx Analyzer.

Some sections may describe equipment not used in your configuration. The user shouldbecome thoroughly familiar with the operation of this module before operating it. Readthis instruction manual completely.

DEFINITIONS

The following definitions apply to DANGERS, WARNINGS, CAUTIONS and NOTES found throughoutthis publication.

DANGER .

Highlights the presence of a hazard which will cause severe personal injury, death, or substantialproperty damage if the warning is ignored.

WARNING .

Highlights an operation or maintenance procedure, practice, condition, statement, etc. If notstrictly observed, could result in injury, death, or long-term health hazards of personnel.

CAUTION.

Highlights an operation or maintenance procedure, practice, condition, statement, etc. If notstrictly observed, could result in damage to or destruction of equipment, or loss of effectiveness.

NOTEHighlights an essential operating procedure,condition or statement.


P-2 Preface Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

SAFETY SUMMARY

If this equipment is used in a manner not specified in these instructions, protective systems may beimpaired.

AUTHORIZED PERSONNEL

To avoid explosion, loss of life, personal injury and damage to this equipment and on-siteproperty, all personnel authorized to install, operate and service the this equipment should bethoroughly familiar with and strictly follow the instructions in this manual. SAVE THESE IN-STRUCTIONS.

DANGER.

ELECTRICAL SHOCK HAZARDDo not operate without doors and covers secure. Servicing requires access to live parts which cancause death or serious injury. Refer servicing to qualified personnel.

This instrument was shipped from factory set up to operate on 115 volt 50/60 Hz. For operation on230 volt 50/60 Hz, refer to Section 2-3.

For safety and proper performance this instrument must be connected to a properly groundedthree-wire source of power.

WARNING

INTERNAL ULTRAVIOLET LIGHT HAZARDUltraviolet light from the ozone generator can cause permanent eye damage. Do not look directly atthe ultraviolet source in ozone generator. Use of ultraviolet filtering glasses is recommended.


March 2002


Model 951C

WARNING

TOXIC CHEMICAL HAZARDThis instrument generates ozone which is toxic by inhalation and is a strong irritant to throat andlungs. Ozone is also a strong oxidizing agent. Its presence is detected by a characteristic pungentodor.

The instrument exhaust contains both ozone and nitrogen dioxide, both toxic by inhalation, andmay contain other constituents of the sample gas which may be toxic. Such gases include variousoxides of nitrogen, unburned hydrocarbons, carbon monoxide and other products of combustionreactions. Carbon monoxide is highly toxic and can cause headache, nausea, loss of conscious-ness, and death.

Avoid inhalation of the ozone produced within the analyzer and avoid inhalation of the sample andexhaust products transported within the analyzer. Avoid inhalation of the combined exhaust prod-ucts at the exhaust fitting.

Keep all tube fittings tight to avoid leaks. See Section 2-8 for Leak Test Procedure.

Connect rear exhaust outlet to outside vent by a 1/4 inch (6.3 mm) or larger stainless steel or Teflonline. Check vent line and connections for leakage.

WARNING .

PARTS INTEGRITYTampering or unauthorized substitution of components may adversely affect safety of this product.Use only factory documented components for repair.

WARNING.

HIGH PRESSURE GAS CYLINDERSThis instrument requires periodic calibration with a known standard gas. See Sections 2-5 and 3-3.See also General Precautions for Handling and Storing High Pressure Gas Cylinders, page P-5.



Model 951C

WARNING.

TOXIC AND OXIDIZING GAS HAZARDThe ozone generator lamp contains mercury. Lamp breakage could result in mercury exposure.Mercury is highly toxic if absorbed through skin or ingested, or if vapors are inhaled.

HANDLE LAMP ASSEMBLY WITH EXTREME CAREIf lamp is broken, avoid skin contact and inhalation in the area of the lamp or the mercury spill.

• Immediately clean up and dispose of the mercury spill and lamp residue as follows:

• Wearing rubber gloves and goggles, collect all droplets of mercury by means of a suction pumpand aspirator bottle with long capillary tube. Alternatively, a commercially available mercuryspill clean-up kit, such as J. T. Baker product No. 4439-01, is recommended.

• Carefully sweep any remaining mercury and lamp debris into a dust pan. Carefully transfer allmercury, lamp residue and debris into a plastic bottle which can be tightly capped. Label andreturn to hazardous material reclamation center.

• Do not place in trash, incinerate or flush down sewer.

• Cover any fine droplets of mercury in non-accessible crevices with calcium polysulfide and sul-fur dust.

WARNING.

TOPPLING HAZARDThis instrument’s internal pullout chassis is equipped with a safety stop latch located on the leftside of the chassis.

When extracting the chassis, verify that the safety latch is in its proper (counter-clockwise) orienta-tion.

If access to the rear of the chassis is required, the safety stop may be overridden by lifting thelatch; however, further extraction must be done very carefully to insure the chassis does not fallout of its enclosure.

If the instrument is located on top of a table or bench near the edge, and the chassis is extracted, itmust be supported to prevent toppling.

Failure to observe these precautions could result in personal injury and/or damage to the product.


March 2002


Model 951C

GENERAL PRECAUTIONS FOR HANDLING AND STORING HIGHPRESSURE GAS CYLINDERS

Edited from selected paragraphs of the Compressed Gas Association's "Handbook of CompressedGases" published in 1981

Compressed Gas Association1235 Jefferson Davis HighwayArlington, Virginia 22202

Used by Permission

1. Never drop cylinders or permit them to strike each other violently.

2. Cylinders may be stored in the open, but in such cases, should be protected against extremes of weatherand, to prevent rusting, from the dampness of the ground. Cylinders should be stored in the shade when lo-cated in areas where extreme temperatures are prevalent.

3. The valve protection cap should be left on each cylinder until it has been secured against a wall or bench, orplaced in a cylinder stand, and is ready to be used.

4. Avoid dragging, rolling, or sliding cylinders, even for a short distance; they should be moved by using a suit-able hand-truck.

5. Never tamper with safety devices in valves or cylinders.

6. Do not store full and empty cylinders together. Serious suckback can occur when an empty cylinder is at-tached to a pressurized system.

7. No part of cylinder should be subjected to a temperature higher than 125°F (52°C). A flame should never bepermitted to come in contact with any part of a compressed gas cylinder.

8. Do not place cylinders where they may become part of an electric circuit. When electric arc welding, precau-tions must be taken to prevent striking an arc against the cylinder.



Model 951C

DOCUMENTATION

The following 951C instruction materials are available. Contact Customer Service Center or the local rep-resentative to order.

748214 Instruction Manual (this document)

COMPLIANCES

This product satisfies all obligations of all relevant standards of the EMC framework in Australia and NewZealand.

N96


March 2002


Model 951C

CONDENSED STARTUP AND CALIBRATION PROCEDURE

The following summarized instructions onstartup and calibration are intended for opera-tors already familiar with the analyzer.

For initial startup, refer to detailed instructionsprovided in Section 3.

1. Set slider switch on the Signal Board to 250ppm (see Figure 3-2).

2. Apply power to the analyzer. The analyzerwill now require approximately one to twohours for temperature equilibrium beforebeing ready for calibration.

3. Verify that the pressure regulator on the cyl-inder of zero gas (nitrogen or air) or samplegas is set for supply pressure of 10 to 17psig.

4. Verify that the pressure regulator on the cyl-inder of air (ozonator supply) is set for supplypressure of 20 to 25 psig.

5. Establish correct pressure of sample gas:

a. Supply sample gas to rear-panel SAM-PLE inlet at 10 to 17 psig (normally 15psig).

b. Adjust SAMPLE Back Pressure Regula-tor so that SAMPLE Pressure Gauge in-dicates the value appropriate to thedesired operating range (normal operat-ing pressure is 3 to 5 psig). See Figure3-1.

6. Establish correct pressure of zero gas:

a. Supply zero gas to rear panel SAMPLEinlet and set to 15 psig.

b. Note reading on SAMPLE PressureGauge. It should be the same as in Step5. b. If not, adjust output pressureregulator on the zero gas cylinder as re-quired.

7. Establish correct pressure of upscale stan-dard gas:

a. Supply upscale standard gas to rearpanel SAMPLE inlet.

b. Note reading on SAMPLE PressureGauge. It should be the same as inStep 6. b. If not, adjust outputregulator on cylinder of upscalestandard gas as required.

NOTESupply pressure for sample, upscalestandard gas and zero air must be thesame. If not, the readout will be in error.

8. Zero Calibration:

a. Set PPM RANGE Switch for range tobe used for sample analysis. SetSPAN Control at normal operatingsetting, if known, or at about mid-range if normal setting is not known.

b. Supply zero gas to rear panel SAM-PLE inlet.

c. Adjust ZERO Control for reading ofzero on meter or recorder.

9. Upscale Calibration:

a. Set PPM RANGE Switch at settingappropriate to the particular spangas.

b. Supply upscale standard gas of ac-curately known NOx content to rearpanel SAMPLE inlet.

c. Adjust SPAN Control so that readingon meter or recorder is equal to theknow parts-per-million concentrationof NOx in the span gas.

NOTEIt is the responsibility of the user tomeasure efficiency of the NO2-to-NOconverter during initial startup, andthereafter at intervals appropriate to theapplication, normally once a month.



Model 951C


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-1

Model 951C

SECTION 1DESCRIPTION AND SPECIFICATIONS

1-1 OVERVIEW

The Model 951C NOx Analyzer is designed tomeasure NOx using one of two sets of rangesdesignated as Hi or Lo. The Hi Range set con-sists of spans with ranges of 0-100, 0-250,0-1000, and 0-2500 ppm NOx. The Lo Rangeset consists of spans with ranges of 0-10, 0-25,0-100, and 0-250 ppm NOx.

The NOx analyzer continuously analyzes aflowing gas sample for NOx [nitric oxide (NO)plus nitrogen dioxide (NO2)]. The sum of theconcentrations is continuously reported as NOx.

The analyzer is based on the chemilumines-cence method of NO detection. The sample iscontinuously passed through a heated bed ofvitreous carbon, in which NO2 is reduced to NO.Any NO initially present in the sample passesthrough the converter unchanged, and any NO2is converted to an approximately equivalent(95%) amount of NO.

The NO is quantitatively converted to NO2 bygas-phase oxidation with molecular ozone pro-duced within the analyzer from air supplied byan external cylinder. During this reaction, ap-proximately 10% of the NO2 molecules are ele-vated to an electronically excited state, followedby immediate decay to the non-excited state,accompanied by emission of photons. Thesephotons are detected by a photomultiplier tube,which in turn generates a DC current propor-tional to the concentration of NOx in the samplestream. The current is then amplified and usedto drive a front panel display and to provide po-tentiometric and isolated current outputs.

To minimize system response time, an internalsample-bypass feature provides high-velocitysample flow through the analyzer.

The display blanks when the analyzer is 10% ormore over-range. Selecting a less sensitive(higher) range restores the display function.

The case heater assembly of the Model951C maintains the internal temperature atapproximately 50oC (122oF).

1-2 TYPICAL APPLICATIONS

The Model 951C Analyzer has specific ap-plications in the following areas:

• Oxides of nitrogen (NOx) emis-sions from the combustion offossil fuels in:

• Vehicle engine ex-haust

• Incinerators

• Boilers

• Gas appliances

• Turbine exhaust

• Nitric acid plant emissions

• Ammonia in pollution controlequipment (with converter)

• Nitric oxide emissions from de-caying organic material (i.e.,landfills).


1-2 Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

1-3 SPECIFICATIONS – LO RANGERanges .......................................... 0 to 10, 0 to 25, 0 to 100, 0 to 250 ppm NOxRepeatability.................................. within 0.1 ppm or ±1% of fullscale, whichever is greaterZero/Span Drift .............................. less than ±0.1 ppm or ±1% of fullscale, whichever is greater, in 24

hours at constant temperatureless than ±0.2 ppm or ±2% of fullscale, whichever is greater, overany 10°C interval from 4 to 40°C (for rate change of 10°C or lessper hour)

Response Time(Electronic + Flow) ................ 90% of fullscale in less than 1 minute

Sensitivity ...................................... less than 0.1 ppm or 1% of fullscale, whichever is greaterDetector Operating Pressure......... atmosphericTotal Sample Flow Rate ................ 1 Liter per minute at 20 psigSample Pressure ........................... 138 kPa (20 psig)Ozone Generator Gas ................... U.S.P. breathing-grade airAmbient Temperature Range ........ 4 to 40°C (40 to 104°F)Analog Output

Potentiometric........................ 0 to +5 VDC, 2000 ohm minimum loadIsolated Current ..................... Field-selectable 0 to 20 or 4 to 20 mA, 700 ohm max loadDisplay ................................... Digital, 4-1/2 digit LCD, readout in engineering units, back-lighted

Power Requirements ..................... 115/230 VAC ±10%, 50/60 ±3 Hz, 570 W maximumEnclosure....................................... General purpose for installation in weather-protected areasDimensions.................................... 8.7 in. x 19.0 x 19.0 in. (H x W x D)

22.0 cm x 48.3 cm x 48.3 cm (H x W x D)Weight ........................................... 22.2 kg (49 lbs) approximate


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-3

Model 951C

1-4 SPECIFICATIONS – HI RANGE

Ranges .......................................... 0 to 100, 0 to 250, 0 to 1000, 0 to 2500 ppm NOxRepeatability.................................. within 0.1 ppm or ±1% of fullscale, whichever is greaterZero/Span Drift .............................. less than ±1.0 ppm or ±1% of fullscale, whichever is greater, in 24

hours at constant temperatureless than ±2.0 ppm or ±2% of fullscale, whichever is greater, overany 10°C interval from 4 to 40°C (for rate change of 10°C or lessper hour)

Response Time(Electronic + Flow)................. 90% of fullscale in less than 1 minute

Sensitivity ...................................... less than 0.1 ppm or 1% of fullscale, whichever is greaterDetector Operating Pressure......... atmosphericTotal Sample Flow Rate ................ 1 Liter per minute at 20 psigSample Pressure ........................... 138 kPa (20 psig)Ozone Generator Gas ................... U.S.P. breathing-grade airAmbient Temperature Range........ 4 to 40°C (40 to 104°F)Analog Output

Potentiometric........................ 0 to +5 VDC, 2000 ohm minimum loadIsolated Current ..................... Field-selectable 0 to 20 or 4 to 20 mA, 700 ohm max loadDisplay ................................... Digital, 4-1/2 digit LCD, readout in engineering units, back-lighted

Power Requirements ..................... 115/230 VAC ±10%, 50/60 ±3 Hz, 570 W maximumEnclosure....................................... General purpose for installation in weather-protected areasDimensions.................................... 8.7 in. x 19.0 x 19.0 in. (H x W x D)

22.0 cm x 48.3 cm x 48.3 cm (H x W x D)Weight ........................................... 22.2 kg (49 lbs) approximate


1-4 Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Installation 2-1

Model 951C

SECTION 2INSTALLATION

2-1 UNPACKING

Carefully examine the shipping carton and con-tents for signs of damage. Immediately notifythe shipping carrier if the carton or its contentsare damaged. Retain the carton and packingmaterial until the instrument is operational.

2-2 LOCATION

See drawing 654063 for Outline and Mountingdimensions.

Install analyzer in a clean area, free from mois-ture and excessive vibration, at a stable tem-perature within 4 to 40°C.

The analyzer should be mounted near the sam-ple source to minimize sample-transport time.

A temperature control system maintains the in-ternal temperature of analyzer at 50°C (122°F)to ensure proper operation over an ambienttemperature range of 4°C to 40°C (40°F to110°F). Temperatures outside these limits ne-cessitate use of special temperature-controllingequipment or environmental protection. Also,the ambient temperature should not change at arate exceeding 10°C/hr.

The cylinders of air and span gas should be lo-cated in an area of constant ambient tempera-ture (±10°C).

2-3 VOLTAGE REQUIREMENTS

WARNING

ELECTRICAL SHOCK HAZARDFor safety and proper performance this in-strument must be connected to a properlygrounded three-wire source of power.

This instrument was shipped from the factoryset up to operate on 115 VAC, 50/60 Hz electricpower. For operation on 230 VAC, 50/60 Hz,position voltage select switches S1, S2, S3 (lo-

cated on the Power Supply Board, Figure 2-1)and S3 (located on the Temperature ControlBoard (Figure 2-2) must be in the 230 VAC po-sition.

Refer to Figure 2-4. Remove the 6.25 A fuse(P/N 902413) and replace with the 3.15 A fuse(P/N 898587) provided in the shipping kit.

2-4 ELECTRICAL CONNECTIONS

The power and output (recorder and current)cable glands are supplied loose in the shippingkit to allow cable installation to connectors orterminal strips.

Cable Gland Part No.Power 899330Recorder 899329

Remove rear cover to access terminals. Routeeach cable through the cable gland and connectto the appropriate connector or terminal strip,tighten the gland.

a. Line Power Connections

Refer to Figure 2-3, Figure 2-4and drawing654063. If this instrument is located on abench or table top or is installed in a pro-tected rack, panel or cabinet, power may beconnected via a 3-wire flexible power cord,minimum 18 AWG (max. O.D. 0.480", min.O./D. 0.270"), through the hole labeledPOWER, utilizing connector gland (P/N899330) provided.

Route the power cable through the cablegland and connect the leads to TB1.Tighten the cable gland adequately to pre-vent rotation or slippage of the power cable.Since the rear terminals do not slide outwith the chassis, no excess power cableslack is necessary.

The following power cord and/or supportfeet (for bench top use) are available:


2-2 Installation Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

CS

115V115V 115V

C10

115V

230VS1

115V

230VS2

115V

230VS3

J5

1

J3

1

J201

655340 POWER SUPPLY BD

115V

115V

230V

115V

115V

230V

115V

115V

230VS1S2 S3

Set switch window for voltage required.

Set switch window for voltage required.

S3

SENSORJ18

POWERSUPPLY

J11

POWERLINEJ5

J19TEST

T.I.F. HEATERJ17 115

230S3

U2

1

2

3

U1

1

1 2 1 2 31

E

B

C Q3

CRR13R2R1Q1

G

A

K

R3R4

C1

Q2

C

B E

CR1

C2 R10 R11 R7 R8 R17R16 R12 CR2

C3

R6

R9 R5

R15 R14

C4 3 2 1

TEMP CONTROL BD

+

AR1

115

R18R19

• Power Cord 634061• North American power cord set

(10 foot)• Enclosure Support Kit 634958• Enclosure support feet (4)• Power Cord/Enclosure Support

Kit 654008

• North American power cord set(10 foot)

• Enclosure support feet (4)

If the instrument is permanently mounted inan open panel or rack, use electrical metaltubing or conduit.

Figure 2-1. Power Supply Board Voltage Select Switches

Figure 2-2. Temperature Control Board


March 2002


Model 951C

EXHAUSTAIRIN

20 PSI (138 kPa)NOMINAL

RECORDEROUTPUT

POWER

+ - G + -

CUROUTPUT

VOLTOUTPUT

L1/HOTL2/NEUT

GND

SAMPLEIN

10 PSI - 17 PSI(70 kPa - 120 kPa)

AC PowerConnections

FUSE

Fuse

Recorder ConnectionsCurrent Output Connections

b. Potentiometric Recorder Connections

Refer to Figure 2-3, Figure 2-4 and drawing654063. Potentiometric recorder connec-tions are made on the rear panel. Routethe potentiometric recorder cable throughthe cable gland in the hole labeled RE-CORDER OUTPUT and connect to VOLTOUTPUT terminals.

Potentiometric recorder cable specificationsare as follows:

• Distance from recorder to analyzer:1000 feet (305 meters) maximum

• Input impedance: Greater than 2000ohms

• Cable (user supplied): Two-conductor,shielded, min. 20 AWG

• Voltage output: 0 to +5 VDC

c. Current Recorder Connections

Refer to Figure 2-3, Figure 2-4 and drawing654063. Current recorder connections aremade on the rear panel. Route the currentrecorder cable through the cable gland inthe hole labeled RECORDER OUTPUTand connect to CUR OUTPUT terminals

Current recorder interconnection cablespecs are as follows:

• Distance the recorder from ana-lyzer: 3000 feet (915 me-ters).maximum

• Load resistance: Less than 700Ohms.

• Cable (user supplied):Two-conductor, shielded, min. 20AWG

As supplied by the factory, the currentoutput produces a zero of 4 mA. Thecurrent output may be adjusted to pro-duce a zero of 0 mA as follows:

1. Zero the instrument as in Section 3-4. Adjust R23, the zero-adjust po-tentiometer on the Power SupplyBoard, to produce 0 mA currentoutput.

Figure 2-3. Cable Gland

Figure 2-4. Rear View of Model 951C (cover removed)

Case Wall

Cable

Nut Gland Nut

INTERIOR EXTERIOR



Model 951C

2-5 GAS REQUIREMENTS

The instrument requires two gases normallysupplied from cylinders. They are:

a. Air (U.S.P. Breathing Grade)

This is used as both (a) an oxygen sourcefor generation of the ozone required for thechemiluminescence reaction, and (b) astandard gas for zero calibration (nitrogencan also be used). Gas for each purposemust be supplied from a separate cylinderdue to different pressure requirements atozonator and zero inlets.

b. Span Gas

This is a standard gas of accurately knowncomposition, used to set an upscale cali-bration point. The usual span gas is NO orNO2 in a background of nitrogen.

WARNING

HIGH PRESSURE GAS CYLINDERSThis instrument requires periodic calibrationwith a known standard gas. See Section 3-3.See also General Precautions for Handlingand Storing High Pressure Gas Cylinders,page P-5.

NOTEFor maximum calibration accuracy, theconcentration of NO in the span gasshould be similar to that in the samplegas. Also, the span gas should be sup-plied to the rear panel SAMPLE inlet atthe same pressure as the sample gas. Toensure constant pressure, a pressureregulator may be utilized immediatelyupstream from the SAMPLE inlet.

Each gas used should be supplied from atank or cylinder equipped with a clean,non-corrosive type, two-stage regulator. Inaddition, a shut-off valve is desirable. Installthe gas cylinders in an area of relativelyconstant ambient temperature.

2-6 SAMPLE REQUIREMENTS

The sample must be clean and dry beforeentering the analyzer. In general, beforeadmission to the analyzer, the sampleshould be filtered to eliminate particleslarger than two microns and have a dewpoint below 90°F (32°C). The factory canprovide technical assistance if desired.

Proper supply pressure for sample, zeroand span gases for the Model 951C is20 psig (138 kPa).

2-7 GAS CONNECTIONS

WARNING

TOXIC AND OXIDIZING GAS HAZARDSThis instrument generates ozone whichis toxic by inhalation and is a strong irri-tant to throat and lungs. Ozone is also astrong oxidizing agent. Its presence isdetected by a characteristic pungentodor.

The instrument exhaust contains bothozone and nitrogen dioxide, both toxicby inhalation, and may contain otherconstituents of the sample gas whichmay be toxic. Such gases include vari-ous oxides of nitrogen, unburned hydro-carbons, carbon monoxide and otherproducts of combustion reactions. Car-bon monoxide is highly toxic and cancause headache, nausea, loss of con-sciousness, and death.

Avoid inhalation of the ozone producedwithin the analyzer and avoid inhalationof the sample and exhaust productstransported within the analyzer. Avoidinhalation of the combined exhaustproducts at the exhaust fitting.

Keep all tube fittings tight to avoid leaks.See Section 2-8 for Leak Test Procedure.

Connect rear exhaust outlet to outsidevent by a 1/4 inch (6.3 mm) or largerstainless steel or Teflon line. Check ventline and connections for leakage.


March 2002


Model 951C

1. Remove plugs and caps from all inlet andoutlet fittings. (See Figure 2-4.)

2. Connect EXHAUST outlet to external ventvia tubing with O.D. of 1/4-inch (6.3 mm) orlarger. Use only stainless steel or Teflontubing.

3. Connect external lines from ozonator airand sample sources to corresponding rearpanel inlet ports. For sample line, stainlesssteel tubing is recommended.

4. Adjust regulator on ozonator air cylinder foroutput pressure of 20 to 25 psig (138 to 172kPa). At least 20 psig should be present atrear of analyzer.

5. Supply sample gas to rear panel SAMPLEinlet at appropriate pressure: 20 psig (138kPa). The nominal input pressure is 20 psig(138 kPa).

2-8 LEAK TEST

The following test is designed for samplepressure up to 5 psig (35 kPa).

1. Supply air or inert gas such as nitrogenat 5 psig (35 kPa) to analyzer sampleand air input fittings.

2. Seal off analyzer exhaust fitting with atube cap.

3. Use a suitable test liquid such asSNOOP (P/N 837801) to detect leaks.Cover all fittings, seals, or possible leaksources.

4. Check for bubbling or foaming which in-dicates leakage, and repair as required.Any leakage must be corrected beforeintroduction of sample and/or applica-tion of electrical power.



Model 951C


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-1

Model 951C

ConverterTemp Check

(S4)

Range SelectSwitch (S1)

SIGNAL BOARD(See Figure 3-2)

Ozone Indicator Lamp(Signal Board DS2)

Span Control(Signal Board R101)

Zero Control(Signal Board R100)

Display(Signal Board DS1)

Signal (R20)

Cal (R18)

Gain (R24)

Adj. (R8)

TP1 TP2

Current OutputSpan (R20)

Current OutputZero (R23)

ConvertorHeater(R9)

PMTHigh Voltage(R30)

Voltage Select(S2)

Voltage Select(S1)

Voltage Select(S3)

CASE HEATER TEMPERATURE CONTROL ASSEMBLY(See Figure 6-4)TEMPERATURE CONTROL BOARD (See Figure 2-2)

Voltage Select(S3)

SAMPLE PRESSUREGAUGE

SAMPLE PRESSUREREGULATOR(Adjustment Knob)

POWER SUPPLY BOARD(See Figure 3-3)

SECTION 3OPERATION

3-1 FRONT PANEL INDICATORS AND CON-TROLS

a. Display

The display is a 4-digit liquid crystal de-vice which always displays NOx concen-tration in parts-per-million. Figure 3-1.

b. Range Selection

The Model 951C has eight customer se-lectable ranges, four LO ranges (10 ppm,25 ppm, 100 ppm and 250 ppm) and fourHI ranges (100 ppm, 250 ppm 1000 ppmand 2500 ppm). The range is selected bypositioning the RANGE Switch (S1) andthe three jumpers on the Signal Board tothe desired range controlling the recorderoutput. Refer to Figure 3-2.

The display blanks for values 10% in ex-cess of the range maximum. Moving the

switch to the left selects a higher fullscalevalue and restores the display.

c. Sample Pressure Gauge

The internal SAMPLE pressure (nominally4 psig, 28 kPa) is adjusted by rotation ofthe Sample Pressure Regulator. SeeFigure 3-1.

d. Ozone Pressure

The OZONE pressure is determined bythe pressure regulator of the air supplycylinder. A nominal pressure of 20 to 25psig (138 to 172 kPa) is recommended.Proper operation is indicated when thefront panel OZONE indicator lamp is lit.

NOTEIf ozone lamp does not light, increasepressure slightly by adjusting pressureregulator control on the air cylinder.

Figure 3-1. Model 951C Controls, Indicators and Adjustments


3-2 Operation Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

e. Zero and Span Potentiometers

See Figure 3-1 and Figure 3-2. Screw-driver access holes through the frontpanel allow adjustments of the ZERO andSPAN potentiometers (R100 and R101 onSignal Board).

f. Ozone Interlock

The ozone-producing UV lamp will not ig-nite or stay lit unless adequate air pres-sure is present at the AIR inlet (seeFigure 2-4). Nominal set point pressure is20 to 25 psig.

3-2 STARTUP PROCEDURE

The following are detailed instructions onstartup and calibration.

1. Supply electrical power to the analyzer.The analyzer will require approximatelytwo hours for temperature equilibrationbefore calibration.

2. On Signal Board, Figure 3-2, set PPMRANGE Switch (S1) to 250 ppm.

3. Establish correct pressure for air by thefollowing:

a. Adjust OZONE Pressure Regulator sothat OZONE Pressure Gauge indi-cates 20 to 25 psig (138 to 172 kPa).

b. To establish correct pressure of zero gas,supply zero gas to rear panel SAMPLEinlet. Note reading on internal SAMPLEPressure Gauge. It should be the sameas the nominal 4 psig (28 kPa) SAMPLEpressure indicated on the internal SAM-PLE pressure gauge. This should remainconstant when the analyzer input SAM-PLE is switched from calibration gasstandard to a zero gas standard. This

may be assured by setting the deliveryfrom the SAMPLE and the zero gas cyl-inder of span gas cylinder to the samevalue of delivery pressure, nominally 20psig (138 kPa). If not, adjust output pres-sure regulator on zero gas cylinder as re-quired.

4. Establish correct pressure of sample gasby the following:

a. Supply sample gas to rear panelSAMPLE inlet.

b. Adjust SAMPLE Backpressure Regu-lator so internal SAMPLE PressureGauge indicates the value appropriateto the desired operating range.

NOTEInability to obtain a flow of one liter perminute at the EXHAUST outlet usuallyindicates insufficient sample supplypressure at the SAMPLE inlet. Use a2400 cc flowmeter (i.e., Brooks P/N1350) at the EXHAUST outlet to meas-ure flow.

2. Establish correct flow of upscale standardgas by the following:

a. Supply upscale standard gas to rearpanel SAMPLE inlet.

b. Note reading on internal SAMPLEPressure Gauge. It should be thesame as in Step 3b.

NOTESupply pressures for sample and up-scale standard gases must be thesame. Otherwise, readout will be in er-ror.

The analyzer is now ready for calibration.


March 2002


Model 951C

J1

10 10025 250S1

CS

ADJ. GAIN SIG. CAL.

E3DP SELECT

E4

E5

TP6 TP5 TP4 TP3 TP2 TP1

E1 E2R39R40R23

DS1

DS2

C

SIGNAL IN

E6E7

K3R28

R29

C14

R34

C15

AR4

RP31

R37

R38

C12

C16

AR6

AR5RP2

R101CWSCCW

SPAN

R22

R100CWSCCW

ZERO

R42

U7

C13

+

CR23

R35

R36 Q3

EB

C

R17

C9 C5 R14 R12 U2

C8

R13

C6

C10

U3+ R16

R15

R31

R30 AR1

R32 R33

Q2E

B

C

K1

K2

VR1

CR1

CR2

CR13

CR14

CR12

CR11

CR10

CR9

CR8

R19

R21

R1

R2

R3

R4

R5

R6

R7

R8

R9

R10

R11

U1RP1

1

R27 R41RANGE

J3

CR3

CR4

CR5

CR6

CR7C7

C11

+CR22

CR21

CR20

CR19

CR18

CR16 CR17

CR15

C17

+

T1R25 R24 R20 R18

C3

C2C1

Q1

C E

B

AR2 AR3

C4

654050 SIGNAL CONTROL BD

E1 E2

E4

E3E5

E1 E2

E4

E3E5

Lo Hi

E7

E6

E7

E6

Lo Hi

10 10025 250S1

HiRange

(S1 pos)ppm

Fullscale1 (10) 1002 (25) 2503 (100) 10004 (250) 2500

LoRange

(S1 pos)ppm

Fullscale1 (10) 102 (25) 253 (100) 1004 (250) 250

R101 - SPAN Potentiometer R100 - ZERO Potentiometer

Figure 3-2. Signal Board



Model 951C

TP3 TP4

VR9

U7

C13

VR5

OGI

C12

I G O

VR4

1 2 3 4

U8CR8 C14

+

C15+

R26

CR7+

+VR6 IGO

TP14 TP15

R22R24R25R21R19

R23

OUTPUTZERO

CURRENTSPAN

R20

J13

J14

CS

C26

+

1 2

J11Q12

E C

E

Q24B

E

C

C22

U9

CR13

R53

R40

R42

R49R47

E

B

Q10

C

Q8G

AC

C

B E

Q9

R54

R4C23

+

R3CR1

THERMOCOOLER

TP1

R9

CONVHTR

RMTHV

R16

S4

R6

BC

EQ2

Q1KG

A

R14

CONVTEMP

CHECK

TP13

CR4CONVERTOR

R4

R2

TP2 TP5 TP6 TP7 TP8

R3

R7

R18 R12 R11

C8

R13J19AR1

Q3

E

C

B

C9

C7+

CR5

R15

CR6

R79

R77

R78

Q15 E

CB

U23

U1

R6

C16

R27

C17

C20+

R28

C18

R64

Q4

EBC

R35

R34R65

R66Q5

R73

CR16

AR2

C19

R74

U22R36

R32

R31

R29

CR10

CR9

R37CR11

E

R38R76

R75

CR24

R70

U20R71

R68

R67

CR23

U21

CR2

B

Q14E C

R62R63

R39

J19R72R69RP11

B

1

J7

2

E

C

BQ7C

B

Q6

R33

CR17

A

O

I

C3

CR20+

C4 CR1

VR3

C5

VR1

VR2

+

+

C2 +

C1

+

+ +

C29

+

+

VR7

G I O

CR18+

C25+

CR2

+

1

J6

R61

CR19

+C27

CR3

R1K1

VR8O G I

C28

+

C6

EB

C

Q13

R60R59

R56R57

R58

J17

1 J2

1

J11

U2

R17R18

C10

115V

115V

230VS1

115V

115V

230VS2

115V

115V

230VS3

J5

1

J3

1

J201

J181

R68

R55

CR12R51

R45R80R81R82

J8

1

J12

1

J4

1

J15

1

J16

1

J91

TP9 TP10 TP11 TP12

C21+

R48R46R44R43R41

CR14

+C11

R30

CR15

THERMOCOOLER

TP1

R9

CONVHTR

PMTHV

S4

CONVTEMP

CHECK

TP13

CR4CONVERTOR

TP2 TP5 TP6 TP7 TP8

C8R23

OUTPUTZERO

CURRENTSPAN

TP14 TP15R20

655340 POWER SUPPLY BD

115V

115V

230VS1

115V

115V

230VS2

115V

115V

230VS3

Figure 3-3. Power Supply Board


March 2002


Model 951C

3-3 CALIBRATION

a. Zero Calibration

1. On the Signal Board, Figure 3-2, setPPM RANGE Switch for the samerange that will be used during sampleanalysis. Set SPAN Control at aboutmid-range.

2. Supply zero gas to rear panel SAM-PLE inlet.

3. After a stable reading is reached, ad-just the zero by inserting a screw-driver in the ZERO slot on the front ofthe analyzer and turning until zeroreading is obtained.

b. Upscale Calibration

1. On the Signal Board, Figure 3-2, setPPM RANGE Switch to the positionappropriate to the particular span gas.

2. Supply upscale standard gas of accu-rately known NOx content to rearpanel SAMPLE inlet.

3. Adjust SPAN Control so that readingon display or recorder is equal to theknown parts-per-million concentrationof NOx in the span gas. If the correctreading is not initially attainable byadjustment of the SPAN Control,make the electronic adjustment inStep 4.

4. If necessary, increase sensitivity byraising photomultiplier voltage. Thiswill interact with zero. Repeat ZeroCalibration and Upscale Calibration(through step 3).

3-4 ROUTINE OPERATION

After calibrating analyzer per Section 3-3,supply sample to SAMPLE inlet. Set PPMRANGE Switch in appropriate position. Theinstrument will now continuously analyze thesample stream.

The Model 951C is designed for continuousoperation. Normally, it is never turned off ex-cept for servicing or for a prolonged shut-down.

NOTEDuring periods of shutdown, turn off theozone lamp by shutting off the input airsource.

3-5 CONVERTER TEMPERATURE ADJUST-MENT PROCEDURE

Once the appropriate high voltage and elec-tronic gain have been selected such that thenamed calibration gas value is indicated bythe Model 951C, the instrument is ready foradjustment of the converter temperature.

The vitreous carbon converter used in thisanalyzer has a low surface area which gradu-ally increases during high temperature opera-tion of the converter material.

Initially, the temperature of the peak of theconverter efficiency starts at a relatively highvalue because significant heat must be sup-plied to make the converter active enough toreduce the input nitrogen dioxide to nitric ox-ide at the required 95% level. During the op-eration of the analyzer, the temperature of thepeak will fall as the surface area of the con-verter is increased and less external energy isrequired to cause adequate conversion.

In extreme cases, where converter re-profilinghas not been conducted, the converter is soactive that it not only reduces nitrogen dioxideto nitric oxide, but it reduces the nitric oxideproduced to nitrogen, which is not detected bythe chemiluminescence reaction. The remedyin this case is to adjust the converter tem-perature to a lower value to improve the con-verter efficiency.

It is important that the converter temperaturebe periodically profiled to assure that it is run-ning at its peak efficiency. An interval of oneweek is recommended. The nominal range ofoperational temperatures for the converter is275°C to 400°C (527°F to 750°F). The oper-



Model 951C

ating temperature of the converter may beconveniently checked by momentarily de-pressing switch S4 on the Power SupplyBoard while monitoring the resistance acrossterminals TP1 and TP2. Table 3-1 allows forconversion of the observed resistance to theoperating temperature for the converter.

Follow this procedure to optimize the operat-ing temperature of the converter:

1. Power instrument and allow it to stabilizeat operating temperature (one to twohours). Measure the operating tempera-ture of the converter by the technique de-scribed above. Note the value for futurereference.

2. Admit a calibration gas of known (NO2)concentration into the analyzer and notethe concentration value determined whenthe full response has been achieved.

3. Refer to Figure 3-3. Turn the convertertemperature adjust potentiometer R9, onthe Power Supply Board one turn coun-terclockwise from the setting establishedat the factory, and allow fifteen minutesfor operation at the new lower tempera-ture setpoint. Recheck the response andnote the value for later use.

4. Increase the temperature of the converterby rotating the converter temperature ad-just potentiometer, R9, one quarter turnclockwise, wait fifteen minutes for thermalequilibrium and then re-measure the NO2calibration gas value. Note its value. Re-peat this procedure of one quarter turnadjustments of the potentiometer, waitingfor thermal stability and determination ofthe calibration gas value until either a95% value is obtained or the final onequarter turn adjustment gives an effi-ciency increase of less than one percent.

5. Decrease the temperature of converteroperation by rotating the converter tem-perature adjust potentiometer one eighthof a turn counterclockwise. This placesthe converter at a temperature suitable forlow ammonia interference and efficientNO2 conversion. Re-measure the indi-

cated converter temperature and compareit to the initially recorded value.

TEMPERATURE(°C)

RESISTANCE(Ohms)

0 40025 438100 552200 704250 780300 856350 932400 1008450 1084

Table 3-1. Resistance of Converter TemperatureSensor vs. Temperature

NOTEConverter temperature is not a directmeasure of converter efficiency. Tempera-ture measurement is for reference pur-poses only.


March 2002


Model 951C

3-6 MEASUREMENT OF CONVERTER EFFI-CIENCY

It is the responsibility of the user to measureefficiency of the NO2-to-NO converter duringinitial startup, and thereafter at intervals ap-propriate to the application (normally once amonth).

The above procedure optimizes the operatingtemperature of the converter. It also serves asan efficiency check if the concentration of NO2in the calibration gas is documented accuraterelative to National Institute of Standards andTechnology (NIST) Reference Materials. If theconcentration of the nitrogen dioxide calibra-tion gas is not known accurately, this proce-dure still serves to adequately provide thecorrect converter operating temperature.

If the only available known standard is the ni-tric oxide calibration standard, the followingprocedure may be performed. This procedurechecks converter efficiency through the utili-zation of gas-phase oxidation of nitric oxideinto nitrogen dioxide over a range of nitrogendioxide concentrations. This technique is ab-stracted and adapted from 40 CFR, Pt. 60,App. A, Method 20, Paragraph 5.6.

1. Select the appropriate instrument range.

2. Admit a nitric oxide in nitrogen NISTtraceable calibration gas of a value be-tween 45% and 55% of the instrumentrange selected to a clean, evacuated,leak tight Tedlar bag. Dilute this gas ap-proximately 1:1 with a 20.9% oxygen, pu-rified air.

3. Immediately attach the bag outlet to theinput of the pump supplying pressurizedgas to the analyzer. It is important to usea sample delivery pump which does notconsume nitrogen dioxide as it deliverssample to the analyzer. Losses of nitro-gen dioxide in the pump will be reportedas converter inefficiency.

4. Operate the analyzer and continue tosample the diluted nitric oxide sample fora period of at least thirty minutes. If thenitrogen dioxide to nitric oxide conversion

is at the 100% level, the instrument re-sponse will be stable at the highest valuenoted.

5. If the response at the end of the thirty mi-nute period decreases more than 2.0 per-cent of the highest peak value observed,the system is not acceptable and correc-tions must be made before repeating thecheck. If it is determined that observedsubnormal conversion efficiencies arereal, and not due to errors introduced bynitrogen dioxide consumption in the sam-ple pump or other parts of the samplehandling system, verify that the converteris peaked at the optimum temperaturebefore replacing with a new converter.



Model 951C

3-7 RECOMMENDED CALIBRATION FRE-QUENCY

After initial startup or startup following a shut-down, the analyzer requires about two hoursfor stabilization before it is ready for calibra-tion. Maximum permissible interval betweencalibrations depends on the analytical accu-racy required, and therefore cannot be speci-

fied. It is recommended that initially theinstrument be calibrated at least once every 8hours. This practice should continue until ex-perience indicates that some other interval ismore appropriate.


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Theory 4-1

Model 951C

SECTION 4 THEORY

4-1 NITRIC OXIDE DETERMINATION BY CHEMI-LUMINESCENCE METHOD

The chemiluminescence method for detection ofnitric oxide (NO) is based on its reaction withozone (O3) to produce nitrogen dioxide (NO2)and oxygen (O2). Some of the NO2 moleculesthus produced are initially in an electronicallyexcited state (NO2*). These revert immediatelyto the ground state, with emission of photons(essentially red light).

The reactions involved are:

NO + O3 → NO2* + O2

NO2* → NO2 + Red Light

As NO and O3 mix in the reaction chamber, theintensity of the emitted red light is proportionalto the concentration of NO.

(Any NO2 initially present in the sample is re-duced to NO by a heated bed of vitreous carbonthrough which the sample is passed before be-ing routed to the reaction chamber.)

The intensity of the emitted red light is meas-ured by a photomultiplier tube (PMT), whichproduces a current of approximately 3 X 10-9

amperes per part-per-million of NO in the reac-tion chamber.

4-2 ANALYZER FLOW SYSTEM

The analyzer flow system is shown in drawing654090. Its basic function is to deliver regulatedflows of sample, calibration gas, or zero gas andozonized air to the reaction chamber. The dis-charge from the reaction chamber flows fromthe analyzer via the EXHAUST outlet.

a. Flow of Sample, Standard Gas or ZeroGas to Reaction Chamber

Suitably pressurized sample, standard gasor zero gas is supplied to the rear panelSAMPLE inlet.

The flow rate of the selected gas intothe reaction chamber is controlled by aback pressure regulator inside the ana-lyzer. It provides an adjustable, con-trolled pressure on the upstream side,where gas is supplied to the calibrated,flow-limiting sample capillary. Theregulator is adjusted for appropriatereading on the internal SAMPLE Pres-sure Gauge. For operation at NO andNO2 levels below 250 ppm, correct set-ting on the SAMPLE Pressure Gauge is4 psig (28 kPa). This results in a flow ofapproximately 60 to 80 cc/min to the re-action chamber.

Excess sample is discharged with theeffluent from the reaction chamber viathe EXHAUST outlet. Bypass flow is setby the restrictor at 1 L/min (nominal) toensure proper functioning of the SAM-PLE Pressure Regulator and rapidsystem response. Excessive changes,on the order of 5 psig (35 kPa), in thepressure of the sample or standard gaswill affect the bypass flow rate and canaffect accuracy.

b. Ozone Generation

Suitably pressurized air from an exter-nal cylinder is supplied to the rear panelAIR inlet. The proper pressure setting is20 to 25 psig (138 to 172 kPa). Withinthe ozone generator, a portion of theoxygen in the air is converted to ozoneby exposure to an ultraviolet lamp. Thereaction is:

From the generator, the ozonized airflows into the reaction chamber for usein the chemiluminescence reaction.

UV3O2 → 2O3


4-2 Theory Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

4-3 SIGNAL PROCESSING ELECTRONICS SYS-TEM

A block diagram of the signal-processing elec-tronics is shown in Figure 4-1. Basic functions ofthese electronics are acceptance of PMT outputand conversion of it to potentiometric and iso-lated current outputs, and providing a visualdisplay of the concentration of the NOx in thesample stream. All functions except thehigh-voltage source and the voltage-to-currentconverter are contained on the Signal ControlPC Board, 654050. The two exceptions are lo-cated on the Power Supply Board, 654059.

The PMT drives a high input impedance ampli-fier which produces a voltage between 0 andapproximately 5 volts. The front panel ZeroControl injects a small current into the PMT am-plifier to null any current from the PMT which isnot related to the concentration of NOx in thesample stream.

The PMT amplifier drives a programmable gainamplifier (PGA). The gain of the PGA is con-trolled by the Range Switch.

The PGA drives the Span Amplifier. The gain ofthis amplifier is controlled by the front panelSpan Control. The output of the Span Amplifieris a voltage which is properly scaled to repre-sent the concentration of NOx in the samplestream.

The Span Amplifier drives the front panelDisplay and associated electronics, and theisolated current output. It also provides thepotentiometric output.

4-4 ANALYZER THERMAL SYSTEM

The Analyzer Thermal System is shown inFigure 4-2. Its basic function is to provide astable thermal environment for the PMT.

The temperature of the PMT must be heldwithin a half-degree band at approximately18°C if it is to produce a useful signal forlow concentrations of NOx. This is accom-plished by means of a solid-state coolerwhich houses the PMT. The heat which isradiated from the cooler is carried away bythe Cooler Fan.

The solid-state cooler must work against arelatively constant load in order to maintainthe temperature of the PMT. This load isproduced by a case heater and exhaust fanwhich control the temperature inside thecase within a one-degree band (approxi-mately 50 C for ambient temperaturesfrom 4°C to 40°C).

The electronics which support the AnalyzerThermal System and the NO2-to-NO Con-verter are contained on the Power SupplyBoard.


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Theory 4-3

Model 951C

Figure 4-1. Analyzer Signal Conditioning Circuit

Figure 4-2. Analyzer Thermal System

High VoltageSupply

Zero Control

PMTAmplifier

ProgrammableGain

Amplifier

SpanAmplifier

PhotomultiplierTube

Display

Voltage-to-CurrentConverter

PotentiometricOutput

IsolatedCurrentOutput

Power Supply Board

Signal/Control Board

Range Switch Span Control

Fan Heater

CASE HEATER

Cooler Fan

Cooling Fins

PMT

SOLID-STATE COOLER

EXHAUST FAN

Top View of Analyzer

FRONT PANEL

INLET VENT HOLES


4-4 Theory Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 5-1

Model 951C

SECTION 5 ROUTINE SERVICING

WARNINGELECTRICAL SHOCK HAZARD

Servicing requires access to live partswhich can cause death or serious injury.Refer servicing to qualified personnel.

WARNING

INTERNAL ULTRAVIOLET LIGHT HAZARDUltraviolet light from the ozone generatorcan cause permanent eye damage. Do notlook directly at the ultraviolet source inozone generator. Use of ultraviolet filter-ing glasses is recommended.

NOTEThe photomultiplier tube must not be exposed toambient light. If the photomultiplier tube is ex-posed to light while the power is on, eitherthrough a loose fitting on the reaction chamberor any other leak, it will be destroyed. If exposedto ambient light with the power off, the tube willbe noisy for some period of time. Unless appro-priate precautions are observed, light can strikethe tube upon removal of fittings from the reac-tion chamber.

5-1 SYSTEM CHECKS AND ADJUSTMENTS

The following procedures may be used to de-termine the cause of unsatisfactory instrumentperformance, or to make adjustments follow-ing replacement of components. If a recorderis available, use it for convenience and maxi-mum accuracy in the various tests.

a. Display Fullscale Span Adjustment

If a recorder is used, and has been prop-erly zeroed, it should agree with the dis-play reading. If not, obtain agreement byadjustment of R20 on the Signal/ControlBoard (see Figure 3-1 and Figure 3-2). Ifagreement cannot be reached, check therecorder. If the recorder is functioningproperly, replace the amplifier board.

b. Overall Sensitivity

Principal factors that determine overallsensitivity of the analyzer are the follow-ing: (a) sample flow rate to the reactionchamber, (b) sensitivity of the photomulti-plier tube (PMT), and (c) PMT high volt-age. If specified fullscale readings areunobtainable by adjustment of the SPANControl, sensitivity is subnormal. Thecause of reduced sensitivity may be ineither the flow system (See Section 5-2)or the electronic circuitry (See Section 5-6).

If either the High Voltage Board or thePhototube/Reaction Chamber Assemblyhas been replaced, a readjustment of thehigh voltage will probably be required toobtain the correct overall sensitivity. Ad-just R30 on the Power Supply Board (seeFigure 3-1 and Figure 3-2) clockwise toincrease (negative) the photomultiplierhigh voltage and sensitivity, or counter-clockwise to decrease (negative) thevoltage and sensitivity. The adjustmentrange is about -650 V to -2100 V for theregulated DC voltage applied to the pho-tomultiplier tube. Nominal setting is -1100volts. However, the voltage should beadjusted as required for overall systemsensitivity.


5-2 Routine Servicing Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

c. Ozone Output

WARNING

TOXIC GAS HAZARDUse extreme caution in troubleshootingthe ozone generator. Ozone is toxic.

To check for adequate output from theozone lamp, a convenient technique is tocalibrate the analyzer on a high level NOstandard such as 250 ppm NO at thenominal 4.0 psi internal sample pressuresetpoint, and note the reading. The sam-ple pressure setpoint is then sequentiallyset to pressures of 3.0, 2.0, and 1.0 psiafter a stable span gas reading has ob-tained at the higher pressure setpoint.The span gas value will change as thepressure is changed. The difference inspan gas value between two successivesample pressure levels should be ap-proximately the same for the 4.0 to 3.0,3.0 to 2.0, and 2.0 to 1.0 pressure steps.

If the size of the span gas value differ-ence increases as the sample pressure islowered, the analyzer output is limited bythe amount of ozone production from thelamp and the two additional checksshould be made. First, verify that thesample flow (not including bypass) doesnot exceed the nominal 60 to 80 cc/min,at 4.0 psi internal sample pressure. Sec-ond, substitute another lamp to see if theozone output is increased.

If no other ozone lamp is available, theanalyzer sample input pressure may bereduced to the pressure where the ozonelimitation is not present. If the lamp outputis low and the sample pressure is reducedto restore operation to the conditionwhere ozone limitation is not occurring,some degradation in analyzer responsetime characteristics may occur.

d. Background Current

With zero air supplied to rear panel SAM-PLE inlet, excessive background currentis evidenced by the inability to obtain zerodisplay reading with adjustment of theZERO Control. If this cannot be accom-plished, the cause must be found and cor-rected. The fault may be in either theelectronic circuitry or the sample flowsystem.

First, establish proper performance of theelectronic circuitry. Turn on analyzerpower. Verify that ZERO Control and am-plifier are functioning properly. Then,check for excessive photomultiplier darkcurrent and/or contamination of the reac-tion chamber or sample flow system asfollows:

• Excessive Photomultiplier Dark Cur-rent

To check, shut off all flow to theozone generator. Turn off ozonegenerator. Supply cylinder air to rearpanel SAMPLE inlet. Note responseon display or recorder. If back-ground is still excessive, possiblecauses are:

leakage of ambient light to photo-multiplier tube

defective photomultiplier tube

electrical leakage in socket assembly

• Contamination of Reaction Chamberor Sample Flow System.

See Section 5-4a.


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Routine Servicing 5-3

Model 951C

5-2 SERVICING FLOW SYSTEM

To facilitate servicing and testing, the Model951C has front drawer access.

Drawing 654090 shows flow system details,including fittings, thread specifications andconnecting tubing.

a. Cleaning Sample Capillary

If clogging of sample capillary is sus-pected, measure flow rate as describedbelow.

1. Turn off instrument power and shut offall gases.

2. Refer to Figure 6-1 and Figure 6-3.Cover and shade the fittings on thereaction chamber with a dark cloth orother light-shielding material. Removethe fitting associated with the samplecapillary and place a cap over theopen fitting to prevent entry of straylight.

NOTEIf the opened fitting is inadvertentlyexposed to ambient light, the instru-ment will temporarily give a highlynoisy background reading. If so, thiscondition may be corrected by leavingthe instrument on, with high voltageon, for several hours. If high voltage ison during exposure, the photomulti-plier tube will be destroyed.

3. With instrument power off, supplysuitable test gas (dry nitrogen or air)to rear-panel SAMPLE inlet.

4. Connect a flowmeter to open end ofsample capillary. Adjust internalSAMPLE Pressure Regulator to nor-mal operating setting of 4 psig (28kPa). Verify that flowmeter indicatesappropriate flow of 60 to 80 cc/min.

5. If flow is correct, restore analyzer tonormal operation.

6. If flow is low, the capillary requirescleaning or replacement (Proceedwith the step 7 below).

7. Clean capillary with denatured alco-hol, and purge with dry nitrogen or airfor one minute. Reconnect capillary.

8. With the photomultiplier still covered,slowly insert the free end of the cap-illary into the corresponding fitting onthe reaction chamber. Push the cap-illary in until it touches bottom againstthe internal fitting. Then tighten fitting1/4 turn past finger tight.

NOTEDo not overtighten capillary internal fit-ting, as overtightened fittings may re-strict the sample flow.

b. Ozone Restrictor Fitting

With instrument power off, supply suitabletest gas (dry nitrogen or air) to rear panelAIR inlet. Cover photomultiplier housingwith a dark cloth. At the fittings on the re-action chamber, disconnect the ozonetube and place a cap over the open fittingto prevent entry of ambient light. Connecta flowmeter to open end of ozone tube.Adjust the OZONE Pressure Regulator sothat the OZONE Pressure Gauge indi-cates normal operating pressure of 20 to25 psig (138 to 172 kPa). Verify that testflowmeter indicates an appropriate flow of500 to 600 cc/min for 20 psig.

Subnormal flow indicates clogging in theflow path that supplies air to the ozonegenerator. This path contains a Restrictor(P/N 655519), consisting of a metal fittingwith internal fritted (metal membrane) re-strictor to reduce pressure. The fitting isupstream from the inlet port of the ozonegenerator. If the internal restrictor be-comes plugged, the assembly (P/N655519) must be replaced as it cannotnormally be cleaned satisfactorily.



Model 951C

5-3 PHOTOMULTIPLIER TUBE/REACTIONCHAMBER

This assembly consists of the photomultipliertube and socket, the thermoelectric cooler,and the reaction chamber. Refer to Figure 6-1for location and details of mounting. Refer toFigure 6-3 for information on the assembly.

The assembly must be removed from theanalyzer in order to clean the reaction cham-ber or to replace the photomultiplier tube.

a. Removal

To remove the photomultipliertube/reaction chamber assembly from theanalyzer, do the follow:

1. Disconnect power from the analyzer.

2. Release pressure from SAMPLE andAIR supplies.

3. Unplug the electrical cable from thePower Supply PC Board.

4. Disconnect the high-voltage cableand the signal cable from the left sideof the assembly. Note the twomounting screws just below the con-nectors.

5. Uncouple the sample and ozone cap-illaries and the exhaust line from theright side of the assembly. Note thetwo mounting screws just below thefittings.

6. Loosen the screws described in steps4 and 5 above.

7. Lift the assembly from the analyzer.

8. Replace the assembly by reversingthe order of steps 1 through 7 above.

b. Cleaning Reaction ChamberNOTE:

Photomultiplier tube will be perma-nently damaged if exposed to ambientlight while powered with high voltage.

Photomultiplier tube will develop tem-porary electronic noise if exposed toambient light with high voltage OFF. Atemporary noisy condition may be cor-rected by leaving instrument on, withhigh voltage on, for several hours. Therequired recovery time depends on in-tensity and duration of the previousexposure. Noise level on the mostsensitive range usually drops to nor-mal within 24 hours.

If sample gas is properly filtered, the re-action chamber should not require fre-quent cleaning. In event of carryover orcontamination, however, the chambershould be disassembled to permit clean-ing the quartz window and the optical fil-ter. The following procedure isrecommended.

1. Cover and shade the ReactionChamber/Photomultiplier Assemblywith a dark cloth or otherlight-shielding material.

NOTEAlways wear surgical rubber gloveswhen handling the reaction chamber toprevent contamination from handling.

2. Note the orientation of the fittings.Slowly rotate and withdraw the reac-tion chamber from the housing. En-sure that no light strikes thephotomultiplier tube.

3. Unscrew plastic end cap, thus freeingthe quartz window and the red plasticoptical filter. Note the sequence inwhich these are assembled.

4. Clean the reaction chamber by theappropriate one of the following twomethods, standard or alternate. Thestandard method is applicable in mostcases. The alternate method is appli-cable when the instrument has shownhigh residual fluorescence. That con-dition is indicated by high residualcurrents on a zero gas and high dif-ferentials between zero gas readings


March 2002


Model 951C

obtained with the ozone lamp on andoff.

Standard Cleaning ProcedureUsing a stiff plastic bristle brush, such asa toothbrush, scrub the Teflon surfaceand gas ports of the reaction chamberwith clean distilled water and Alconox*detergent (P/N 634929). Alconox deter-gent is included in the shipping kit pro-vided with the Model 951C NOx Analyzer,and is available from Sargent-Welch Sci-entific Company under its catalog numberS-195650-A.

Using Alconox and clean, soft facial tissue(NOT industrial wipes), carefully clean thequartz window. Vigorously flush reactionchamber and quartz window with cleandistilled water. Blow out all possible waterfrom internal passages of reaction cham-ber. Dry reaction chamber and quartzwindow in a warm oven at 125°F to 150°F(52°C to 66°C) for 30 to 45 minutes orpurge-dry the parts with dry cylinder air ornitrogen to eliminate all moisture.

WARNING

ACID HAZARDHydrochloric acid (HC1) is a strong acid. Itis irritating to the skin, mucous mem-branes, eyes and respiratory tract. Directcontact causes severe chemical burns.Avoid Contact with eyes and skin andavoid breathing fumes. Use in hood or wellventilated place. Wear goggles, rubbergloves and protective clothing.

Alternate Cleaning Procedure - ForHigh Residual FluorescenceHolding the reaction chamber by the tubefittings, and using appropriate caution,immerse the white Teflon part of thechamber in 50% concentrated ReagentGrade hydrochloric acid. After five min-utes, rinse thoroughly with de-ionizedwater, then air dry as in the standardcleaning method above.

Place parts in position and press onend-cap so that mating threads engageproperly, without cross threading. Turnmating parts in one continuous motionuntil the parts mesh. Do not over-torque.

With reaction chamber now assembled,replace and reconnect it in reversed re-moval sequence. Orient as noted in step2.

c. Photomultiplier Tube and Housing

The photomultiplier tube operates at highDC voltages (nominal setting is -1100volts) and generates small currents thatare highly amplified by the sig-nal-conditioning circuitry. It is thereforeimportant that ambient humidity and con-densed water vapor be excluded from theinterior of the photomultiplier housing.Ambient humidity can result in electricalleakage, observed as abnormally highdark current. Water vapor or condensedmoisture in contact with the photomulti-plier tube may result in an abnormallyhigh noise level during instrument readouton zero air or upscale standard gas.

The Photomultiplier Tube/ReactionChamber Assembly incorporates severalfeatures for exclusion of humidity andmoisture. The photomultiplier socket as-sembly is potted with high impedance sili-cone rubber compound and is sealedfrom external influences with epoxy andrubber gasket material. The socket as-sembly and the reaction chamber aresealed with O-rings into opposite ends ofthe tubular photomultiplier housing. Thesocket end of the housing may be sealedwith either one or two O-rings, dependingon the length of the phototube.



Model 951C

d. Replacement of Photomultiplier Tube

The photomultiplier tube assembly mustbe removed from the housing in order toreplace the tube. To remove, do the fol-lowing:

1. Note the orientation of the connec-tors.

2. Slowly rotate and withdraw the socketassembly from the housing. Note theorientation and placement of themetal shield and the black plastic in-sulating cover.

3. Carefully unplug the photomultipliertube from the socket.

4. Plug a new tube into the socket.

5. Orient the metal shield and blackplastic insulator as noted in step 2.

6. Carefully rotate and insert the tube,shield and cover into the housing.Orient as noted in step 1.


March 2002


Model 951C

5-4 OZONE GENERATION SYSTEMThis system consists of the ultraviolet lamp,lamp housing, and power supply. Refer toFigure 6-1 for location and details of mount-ing.

WARNING

TOXIC CHEMICAL HAZARDThe ozone generator lamp contains mer-cury. Lamp breakage could result in mer-cury exposure. Mercury is highly toxic ifabsorbed through skin or ingested, or ifvapors are inhaled.

Handle lamp assembly with extreme care.

If lamp is broken, avoid skin contact andinhalation in the area of the lamp or themercury spill.

Immediately clean up and dispose of themercury spill and lamp residue as follows:

• Wearing rubber gloves and goggles,collect all droplets of mercury bymeans of a suction pump and aspiratorbottle with long capillary tube. Alter-natively, a commercially available mer-cury spill clean-up kit, such as J. T.Baker product No. 4439-01, is recom-mended.

• Carefully sweep any remaining mer-cury and lamp debris into a dust pan.Carefully transfer all mercury, lampresidue and debris into a plastic bottlewhich can be tightly capped. Labeland return to hazardous material rec-lamation center.

Do not place in trash, incinerate or flushdown sewer.

Cover any fine droplets of mercury in non-accessible crevices with calcium polysul-fide and sulfur dust.

a. Lamp/Housing Removal

To remove the lamp and housing, do thefollow:

1. Disconnect power from the instru-ment.

2. Release pressure from SAMPLE andAIR supplies.

3. Disconnect the air supply tubing fromthe front of the housing.

4. Disconnect the ozone tube leading tothe reaction chamber.

5. Disconnect the power cable from thePower Supply.

6. Uncouple the two Velcro straps whichsecure the housing to power supply.

7. Lift the housing from the analyzer.

b. UV Lamp Replacement

To replace the lamp, do the following:

1. Unscrew and remove end cap.

2. Unscrew aluminum outer lamp hous-ing tube from lamp base, using carenot to hit or touch lamp assembly.

NOTE:Do not touch lamp. Fingerprints maycause a decrease in lamp output.

3. Replace O-ring in lamp base with newO-ring supplied in kit.

4. Insert replacement lamp assemblyusing care not to hit or touch lamphousing.

5. Insert new O-ring into new end cap.Screw end cap onto end of lamphousing.

Replace the lamp and housing by revers-ing the steps in this section.



Model 951C

c. Power Supply Removal

To remove the Power Supply, do the fol-lowing:

Refer to Figure 6-1.

1. Remove the lamp and housing as inSection 5-4b.

2. Disconnect the power lead from thePower Supply Board.

3. Remove the two screws which securethe Power Supply to the bottom plateof the analyzer.

4. Lift the Power Supply from the ana-lyzer.

5. Replace the Power Supply by re-versing the order of the steps in thissection.


March 2002


Model 951C

5-5 CONVERTER ASSEMBLY

To check the heater blanket, verify the conti-nuity of the heater coil.

To check the temperature sensor, refer toSection 3-4 and measure its resistance wheninstrument power is off (should be about 440ohms) and when instrument power is on(should range from 800 to 1,000 ohms). SeeTable 3-1.

To remove the glass converter tube (seeFigure 6-4):

1. Carefully disconnect the blue silicon con-nectors from the ends of the inlet andoutlet tubes.

2. The inlet tube is partially filled with glasswool and has a larger inside diameterthan the outlet tube. Further, the outlet

tube and the sample capillary (P/N615989) connect to the same stainlesssteel tee.

3. Release the assembly and disconnect theheater and sensor connectors from thetemperature control board.

4. Remove the lacing from the heater blan-ket, and remove the converter tube. Notethe position of the temperature sensorand its leads as the aluminum foil is un-wrapped.

5. Replace the defective part and reassem-ble. The temperature sensor should con-tact the converter tube with the top of thesensor at the midpoint of the converter.Route sensor leads axially to the outerend.

6. Condition the converter as described inSections 3-4 and 3-5.



Model 951C

5-6 SERVICING ELECTRONIC CIRCUITRY

For troubleshooting the electronic system,refer to Section 4 and the appropriate pictorialdiagrams at the back of the manual. Theelectronic system utilizes printed circuitboards with solid-state components. After amalfunction is traced to a particular board, therecommended procedure is to return it to thefactory for repair.

5-7 LEAKS

Liberally cover all fittings, seals, and otherpossible sources of leakage with a suitableleak test liquid such as SNOOP (part837801). Bubbling or foaming indicates leak-age. Checking for bubbles will locate mostleaks but could miss some, as some areasare inaccessible to the application of SNOOP.For positive assurance that system is leakfree, perform one of the tests above.


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Replacement Parts 6-1

Model 951C

SECTION 6 REPLACEMENT PARTS

WARNING

PARTS INTEGRITYTampering with or unauthorized substitution of components may adversely affect safety of this product.Use only factory-approved components for repair.

6-1 MATRIXEach analyzer is configured per the customersales order. Below is the 951C sales matrixwhich lists the various configurations avail-able.

To identify the configuration of an analyzer,locate the analyzer name-rating plate. Thesales matrix identifier number appears on theanalyzer name-rating plate.

951C MODEL 951C NOx ANALYZER

Code Ranges01 Standard - Four 0-10, 0-25, 0-100, 0-250 ppm NOx02 High Range 0-100, 250, 1000, 2500 ppm NOx99 Special

Code Output01 Standard - 0-5 VDC, 0/4-20 mA99 Special

Code Case01 Standard02 EMC Protected99 Special

Code Tropicalization00 None01 Tropicalized Electronics

951C 02 01 02 01 Example


6-2 Replacement Parts Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

6-2 CIRCUIT BOARD REPLACEMENT POLICY

In most situations involving a malfunction of acircuit board, it is more practical to replace theboard than to attempt isolation and replace-ment of the individual component. The cost oftest and replacement will exceed the cost of arebuilt assembly from the factory.

The following list does not include individualelectronic components. If circumstances ne-cessitate replacement of an individual compo-nent which can be identified by inspection orfrom the schematic diagrams, obtain the re-placement component from a local source ofsupply.

6-3 REPLACEMENT PARTS

The following parts are recommended for rou-tine maintenance and troubleshooting of theModel 951C NOx Analyzer. If the trouble-shooting procedures do not resolve the prob-lem, contact your local Rosemount Analyticalservice office. A list of Rosemount AnalyticalService Centers is located in Section 7.

a. Common Parts


655519 Air Restrictor Fitting657091 Capacitor Assembly655166 Capillary, Bypass655589 Capillary, Sample Hi623719 Capillary, Sample Lo654068 Temperature Control Assembly654070 Converter Assembly655303 Exhaust Fan654052 Fan Assembly898587 Fuse 3.15 A902413 Fuse 6.25 A654390 I/O Assembly652173 Ozone Generator658156 Ozone Generator UV Lamp

Replacement Kit655129 Ozone Generator Power Supply654062 Photomultiplier Assembly655332 Power Supply Assembly654085 Pressure Switch623936 Sample Flow Restrictor644055 Sample Pressure Gauge815187 Sample Regulator622917 Sensor, Temperature654050 Signal Board654878 Transformer/Inductor Assembly


March 2002


Model 951C

Sample Regulator815187 Sample Pressure Gauge

644055

I/O Assembly654390

Sample Flow Restrictor623936

Air Restrictor655519 (on Ozone Generator inlet)

Transformer/Inductor Assembly654878

Fan Assembly654052

Pressure Switch654085

Case Heater TemperatureControl Assembly 654068(See Figure 6-4)

Converter Assembly654070 (See Figure 6-3)

Photomultiplier Assembly654062 (See Figure 6-2)

Ozone Generator Power Supply655129

Ozone Generator 658156UV Lamp Replacement Kit 658156

Exhaust Fan655303

Power Supply Assembly655332

Sensor622917

Figure 6-1. Major Assemblies of the Model 951C



Model 951C

Socket Assembly654086

Reaction Chamber 654381

Photomultiplier Tube and MagneticShield (PN 630916) to be Flush

.3

Photomultiplier Tube

Magnetic Shield630916

PVC Tube

Note: Silicone lubricant to be applied to o-rings.

Thermocooler Housing654943


O-Ring 008423

Thermal Shield 639722Insulating Washer 649541


PVC Tube

O-Rings 001522

Photomultiplier Tube655168

b. Photomultiplier Assembly 654062


654943 Housing649541 Insulating Washer636318 Magnetic Shield630916 Magnetic Shield

001522 O-Ring008423 O-Ring, Photomultiplier655168 Photomultiplier Tube654381 Reaction Chamber654086 Socket Assembly639722 Thermal Shield

Figure 6-2. Photomultiplier Housing Assembly


March 2002


Model NGA 2000 TO2

c. Converter Assembly 654070


632784 Connector, Blue Silicone657127 Heater632782 Temperature Sensor632795 Tube

Figure 6-3. Converter Assembly

Connectors, GlassTube632784

Heater657127

Temperature Sensor632782

Converter Tube - Packed632795



Model 951C

Heater633732

Heater CableOrientation

Fan622733

Temperature Control Board655335

Thermal Fuse900492

d. Temperature Control Assembly 654068


622733 Fan622732 Heater655335 Temperature Control Board900492 Thermal Fuse

Figure 6-4. Case Heater Temperature Control Assembly


March 2002

Rosemount Analytical Inc. A Division of Emerson Process Management Return of Material 7-1

Model NGA 2000 TO2

SECTION 7RETURN OF MATERIAL

7-1 RETURN OF MATERIALIf factory repair of defective equipment is re-quired, proceed as follows:1. Secure a return authorization from a

Rosemount Analytical Inc. Sales Office orRepresentative before returning theequipment. Equipment must be returnedwith complete identification in accordancewith Rosemount instructions or it will notbe accepted.Rosemount CSC (Customer ServiceCenter) will provide the shipping addressfor your instrument.In no event will Rosemount be responsi-ble for equipment returned without properauthorization and identification.

2. Carefully pack the defective unit in asturdy box with sufficient shock absorbingmaterial to ensure no additional damageoccurs during shipping.

3. In a cover letter, describe completely:• The symptoms that determined the

equipment is faulty.• The environment in which the equip-

ment was operating (housing,weather, vibration, dust, etc.).

• Site from where the equipment wasremoved.

• Whether warranty or non-warrantyservice is expected.

• Complete shipping instructions for thereturn of the equipment.

4. Enclose a cover letter and purchase orderand ship the defective equipment ac-cording to instructions provided in theRosemount Return Authorization, prepaid,to the address provided by RosemountCSC.

Rosemount Analytical Inc.Process Analytical DivisionCustomer Service Center

1-800-433-6076

If warranty service is expected, the defectiveunit will be carefully inspected and tested atthe factory. If the failure was due to the condi-tions listed in the standard Rosemount war-ranty, the defective unit will be repaired orreplaced at Rosemount’s option, and an oper-ating unit will be returned to the customer inaccordance with the shipping instructions fur-nished in the cover letter.For equipment no longer under warranty, theequipment will be repaired at the factory andreturned as directed by the purchase orderand shipping instructions.

7-2 CUSTOMER SERVICEFor order administration, replacement Parts,application assistance, on-site or factory re-pair, service or maintenance contract informa-tion, contact:

Rosemount Analytical Inc.Process Analytical DivisionCustomer Service Center

1-800-433-6076

7-3 TRAININGA comprehensive Factory Training Program ofoperator and service classes is available. Fora copy of the Current Operator and ServiceTraining Schedule contact the TechnicalServices Department at:

Rosemount Analytical Inc.Phone: 1-714-986-7600FAX: 1-714-577-8006


7-2 Return of Material Rosemount Analytical Inc. A Division of Emerson Process Management

Model 951C

WARRANTY

Goods and part(s) (excluding consumables) manufactured by Seller are warranted to be free fromdefects in workmanship and material under normal use and service for a period of twelve (12)months from the date of shipment by Seller. Consumables, glass electrodes, membranes, liquidjunctions, electrolyte, o-rings, etc., are warranted to be free from defects in workmanship andmaterial under normal use and service for a period of ninety (90) days from date of shipment bySeller. Goods, part(s) and consumables proven by Seller to be defective in workmanship and/ormaterial shall be replaced or repaired, free of charge, F.O.B. Seller's factory provided that thegoods, part(s) or consumables are returned to Seller's designated factory, transportation chargesprepaid, within the twelve (12) month period of warranty in the case of goods and part(s), and inthe case of consumables, within the ninety (90) day period of warranty. This warranty shall be ineffect for replacement or repaired goods, part(s) and the remaining portion of the ninety (90) daywarranty in the case of consumables. A defect in goods, part(s) and consumables of the com-mercial unit shall not operate to condemn such commercial unit when such goods, part(s) andconsumables are capable of being renewed, repaired or replaced.

The Seller shall not be liable to the Buyer, or to any other person, for the loss or damage directlyor indirectly, arising from the use of the equipment or goods, from breach of any warranty, or fromany other cause. All other warranties, expressed or implied are hereby excluded.

IN CONSIDERATION OF THE HEREIN STATED PURCHASE PRICE OF THE GOODS,SELLER GRANTS ONLY THE ABOVE STATED EXPRESS WARRANTY. NO OTHER WAR-RANTIES ARE GRANTED INCLUDING, BUT NOT LIMITED TO, EXPRESS AND IMPLIEDWARRANTIES OR MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

Limitations of Remedy. SELLER SHALL NOT BE LIABLE FOR DAMAGES CAUSED BY DE-LAY IN PERFORMANCE. THE SOLE AND EXCLUSIVE REMEDY FOR BREACH OF WAR-RANTY SHALL BE LIMITED TO REPAIR OR REPLACEMENT UNDER THE STANDARDWARRANTY CLAUSE. IN NO CASE, REGARDLESS OF THE FORM OF THE CAUSE OF AC-TION, SHALL SELLER'S LIABILITY EXCEED THE PRICE TO BUYER OF THE SPECIFICGOODS MANUFACTURED BY SELLER GIVING RISE TO THE CAUSE OF ACTION. BUYERAGREES THAT IN NO EVENT SHALL SELLER'S LIABILITY EXTEND TO INCLUDE INCIDEN-TAL OR CONSEQUENTIAL DAMAGES. CONSEQUENTIAL DAMAGES SHALL INCLUDE, BUTARE NOT LIMITED TO, LOSS OF ANTICIPATED PROFITS, LOSS OF USE, LOSS OF REVE-NUE, COST OF CAPITAL AND DAMAGE OR LOSS OF OTHER PROPERTY OR EQUIPMENT.IN NO EVENT SHALL SELLER BE OBLIGATED TO INDEMNIFY BUYER IN ANY MANNERNOR SHALL SELLER BE LIABLE FOR PROPERTY DAMAGE AND/OR THIRD PARTY CLAIMSCOVERED BY UMBRELLA INSURANCE AND/OR INDEMNITY COVERAGE PROVIDED TOBUYER, ITS ASSIGNS, AND EACH SUCCESSOR INTEREST TO THE GOODS PROVIDEDHEREUNDER.

Force Majeure. Seller shall not be liable for failure to perform due to labor strikes or acts beyondSeller's direct control.


© Rosemount Analytical Inc. 2001

Emerson Process ManagementRosemount Analytical Inc.Process Analytic Division1201 N. Main St.Orrville, OH 44667-0901T (330) 682-9010F (330) 684-4434E [email protected]

ASIA - PACIFICFisher-RosemountSingapore Private Ltd.1 Pandan CrescentSingapore 128461Republic of SingaporeT 65-777-8211F 65-777-0947http://www.processanalytic.com

Fisher-Rosemount GmbH & Co.Industriestrasse 163594 HasselrothGermanyT 49-6055-884 0F 49-6055-884209

EUROPE, MIDDLE EAST, AFRICAFisher-Rosemount Ltd.Heath PlaceBognor RegisWest Sussex PO22 9SHEnglandT 44-1243-863121F 44-1243-845354

LATIN AMERICAFisher - RosemountAv. das Americas3333 sala 1004Rio de Janeiro, RJBrazil 22631-003T 55-21-2431-1882

Model 951C

Documents

NOx Analyzer - Automation Solutions Rosemount...NOx Analyzer Emerson Process Management Rosemount Analytical Inc. Process Analytic Division 1201 N. Main St. Orrville, OH 44667-0901