Applications of Hydraulics&Pneumatics : Session 13

8/3/2019 Applications of Hydraulics&Pneumatics : Session 13

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13pplications of

Hydraulic Pneumatics&By: Alireza Safikhani

2 Air Compressors & Distribution System When air is compressed itWhen air is compressed it

rises dramatically inrises dramatically in

temperaturetemperature The natural water vapourThe natural water vapour

content of air (relativecontent of air (relative

humidity) is concentratedhumidity) is concentrated

and carried through theand carried through the

compression process as acompression process as a

vapour in the highvapour in the high

temperaturetemperature

As the air cools waterAs the air cools water

condenses out makingcondenses out making

freshly compressed air veryfreshly compressed air very

wetwet

Solid particles will also beSolid particles will also be

present, these can consistpresent, these can consist

of fragments of burntof fragments of burntcompressor lubricating oilcompressor lubricating oil

and airborne dust inhaledand airborne dust inhaled

by the compressorby the compressor

Preparation of compressedPreparation of compressed

air consists of reducingair consists of reducing

temperature, removingtemperature, removing

water and solids,water and solids,

controlling pressure and incontrolling pressure and in

many cases addingmany cases addinglubricantlubricant

3

Condition of Air

For the continuing performance of control systemsFor the continuing performance of control systems

and working elements, it is necessary to guaranteeand working elements, it is necessary to guarantee

that the air supply is:that the air supply is:

at the required pressure,at the required pressure, drydry

cleanclean

4

Components of air Preparation

The equipment to be considered in the generation andThe equipment to be considered in the generation andpreparation of air include:preparation of air include:

Inlet filterInlet filter

Air compressorAir compressor Air reservoirAir reservoir

Air dryerAir dryer

Air filter with water separatorAir filter with water separator

Pressure regulatorPressure regulator

Air lubricator as requiredAir lubricator as required

Drainage pointsDrainage points


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6 Pressure level As a rule, pneumatic components are designed for aAs a rule, pneumatic components are designed for a

maximum operating pressure of 800 to 1000maximum operating pressure of 800 to 1000 kPakPa (8(8--

10 bar).10 bar). Practical experience has shown, however,Practical experience has shown, however,that approximatelythat approximately 600600 kPakPa (6 bar) should be used for(6 bar) should be used for

economic operationeconomic operation..

Pressure losses of between 10 and 50Pressure losses of between 10 and 50 kPakPa (0.1 and 0.5(0.1 and 0.5

bar) must be expected due to the restrictions, bends,bar) must be expected due to the restrictions, bends,

leaks and pipeleaks and pipe--runs, depending on the size of theruns, depending on the size of the

piping system and the method of layout.piping system and the method of layout.

The compressor's system should provideThe compressor's system should provide at least 650at least 650to 700to 700 kPakPa (6.5 to 7 bar) for a desired operating(6.5 to 7 bar) for a desired operating

pressure level of 600pressure level of 600 kPakPa (6 bar).(6 bar).

7

Compressor Selection

the various types of compressors available andthe various types of compressors available and

selection of appropriate Compressorselection of appropriate Compressor is dependentis dependent

uponupon quantity of air, pressure, quality and cleanlinessquantity of air, pressure, quality and cleanliness

and how dry the airand how dry the air should be.should be. There are varying levels of these criteria depending onThere are varying levels of these criteria depending on

the type of compressor.the type of compressor.

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17 Reservoirs configured downstream of a compressor toconfigured downstream of a compressor to stabilisestabilise

compressed air.compressed air.

compensates the pressure fluctuations when thecompensates the pressure fluctuations when thecompressed air is taken from the system.compressed air is taken from the system.

If the pressure drops below a certain value, theIf the pressure drops below a certain value, the

compressor will compensate until the set higher valuecompressor will compensate until the set higher value

is reached again.is reached again.

the compressor does not need to operatethe compressor does not need to operate

continuously. The large surface area of the reservoircontinuously. The large surface area of the reservoir

cools the air. Thus, a portion of the moisture in the aircools the air. Thus, a portion of the moisture in the airis separated directly from the reservoir as water,is separated directly from the reservoir as water,

which has to be regularly drained via a drain cock.which has to be regularly drained via a drain cock.

18 size of a compressed air reservoir Delivery volume of the compressor

Air consumption for the applications

Network size (any additional requirements)

Type of compressor cycle regulation

Permissible pressure drop in the supply network

19

Delivery volume q L = 20 m3/minDelivery volume q L = 20 m3/min

Switching cycles per hour z = 20 1/hSwitching cycles per hour z = 20 1/h

Differential pressureDifferential pressure p = 1 barp = 1 bar

Result: Reservoir size VB = 15 m3Result: Reservoir size VB = 15 m3

Volume of a reservoir20

Air dryers

The service life of pneumatic systems is considerablyThe service life of pneumatic systems is considerably

reduced if excessive moisture is carried through thereduced if excessive moisture is carried through the

air system to the components.air system to the components.

Therefore it is important to fit the necessary air dryingTherefore it is important to fit the necessary air dryingequipment to reduce the moisture content to a levelequipment to reduce the moisture content to a level

which suits the application and the components used.which suits the application and the components used.

There are three auxiliary methods of reducing theThere are three auxiliary methods of reducing the

moisture content in air:moisture content in air:

Low temperature dryingLow temperature drying

Adsorption dryingAdsorption drying

Absorption dryingAbsorption drying


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Automatic drain valve

When water level rises valveopens to eject the water

then closes again When no pressure, valve

opens to drain system

Unit fits in the bottom of afilter or drip leg drain

Nylon mesh 500 m toprevent large solid particlesclogging internals

Dead zone where largeparticles may settle

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Float breathable forpressure equalisation,

internally splined to preventrotation

Air inlet seat

Air exhaust seat

Piston and drain valve spool

Exhaust valve wire can bepushed from below tooverride and lift the float

Connection for piping awaycontaminant

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Pressure first applied to thebowl fully lifts the piston sothe drain is closed

The wire cracks open thefloat inlet seat until a forcebalance exists across thepiston in the closed position

Changing bowl pressure,slightly lifts or lowers thepiston to adjust thebalancing pressure

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Water level rises but notenough to lift the float

Force holding the float down

is the pressure differentialacting on the float above theinlet seat area

Water takes on the samepressure as the compressedair in the bowl


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Water high enough to lift thefloat

Air pressure on top of thepiston balances thepressure under it

Spring pushes piston downto open the valve

Water ejected underpressure

Exhaust seat open but air

enters faster than it canleave so the piston staysopen

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Float drops and reseals inletseat

Water still being ejected asthe valve starts to slowlyclose

Piston pushed up slowlyagainst air pressure on topof the piston as it escapesthrough the restrictedexhaust seat

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Piston in the up positionfully closing the valve

The cycle is repeated

whenever there is sufficientwater to lift the float

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When system pressure isturned off and exhausted thespring will push the pistondown to open the valve

Any water gradually drainingthrough a depressurisedsystem will be able to passthrough the open drain valve


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Semi-automatic drain

When the pressure is turnedoff at the end of the day or at

any other time the drainvalve will open automatically

In most applications thenormal daily cycle will keepthe bowl cleared

If the bowl needs drainingwhile under pressure thiscan be achieved manuallyby pushing up on the pipe

connector

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When air pressure is OFFthe valve springs to the

open position and drainingoccurs

Water contained in the bowlwill be cleared

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When air pressure is ON thevalve is pushed closed

Water will start to build up in

the bowl If the level becomes too high

before the pressure isturned off it can be drainedunder pressure manually

Push up on the pipeconnector and hold untildraining is complete

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Water will start to build up in

the bowl If the level becomes too high

before the pressure isturned off it can be drainedunder pressure manually



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Water will start to build up inthe bowl

If the level becomes too highbefore the pressure isturned off it can be drainedunder pressure manually


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Water will start to build up inthe bowl

If the level becomes too highbefore the pressure isturned off it can be drainedunder pressure manually


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Fully automatic drain valve

In normal working underpressure, the float will liftwhen the water level rises

This causes the valve toopen and the water isejected

The float falls and the valvecloses

When the pressure is turnedoff at the end of the day or atany other time the drainvalve will open automatically

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In normal working underpressure, the float will liftwhen the water level rises

This causes the valve toopen and the water isejected




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In normal working underpressure, the float will lift

when the water level rises This causes the valve to

open and the water isejected



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FRL

FRL stands for filter, regulator and lubricatorFRL stands for filter, regulator and lubricator

When an FRL unit is referred to, it means a combination ofWhen an FRL unit is referred to, it means a combination of

these three devices closely connected togetherthese three devices closely connected together They form a unit that will prepare the condition ofThey form a unit that will prepare the condition of

compressed air just before delivering it to pneumaticcompressed air just before delivering it to pneumatic

equipment or machineryequipment or machinery

This ensures the air supply is clean and dry, the pressure is atThis ensures the air supply is clean and dry, the pressure is at

the correct level and fine particles of oil are carried in the athe correct level and fine particles of oil are carried in the a irir

to lubricate the wearing parts within valves, cylinders andto lubricate the wearing parts within valves, cylinders and

toolstools

A convenient method of combining these components is toA convenient method of combining these components is touse a modular systemuse a modular system

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FRL

shown with gauge, shut offshown with gauge, shut off

valve and wall mountingvalve and wall mounting

bracketsbrackets

Updated system based onUpdated system based onthe popular modular yokethe popular modular yoke

with plug in unitswith plug in units

Extensive range of plug inExtensive range of plug in

unitsunits

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Olympian Plus

Quick connect yokes

Plug in unit

Bayonet bowls

Prismatic sight glass Captive O Rings

Tamper resistant cover

Pressure switch

Soft start/dump

Shut off valve 3/2

1

2

3

4

5

6

7

8

9

1


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Filter (general principle)

Separate and collectcontaminants

Angled louvers spin the airas it enters the bowl

Water droplets and largesolid particles spunoutwards against bowl andrun to the bottom

Baffle prevents turbulent airsplashing water on to thefilter element

Element traps finer solidparticles

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Filter (with manual drain)

Daily visual inspection isrequired to ensure the water

contaminant level isprevented from rising to alevel where it can be drawnthrough the filter element

A quarter turn valve allowsthe contaminant to beejected under pressure

Threaded end allows a tubeconnection for draining to a

suitable container

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Filter (with metal bowl)

Refraction grid clearlyindicates contaminant level

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Filter (with service indicator)

As a filter element becomesclogged the flow decreases

The developing pressure

differential acting on thediaphragm lifts the redsleeve

The filter element must thenbe replaced


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Filter (with service indicator)

As a filter element becomesclogged the flow decreases

The developing pressuredifferential acting on thediaphragm lifts the redsleeve

The filter element must thenbe replaced

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Coalescing filters

For applications where theFor applications where the

air is to be exceptionallyair is to be exceptionally

clean and free of oilclean and free of oil For use in food and drugFor use in food and drug

processing, air bearings andprocessing, air bearings and

paint spraying etc.paint spraying etc.

SubSub--micrometremicrometre particleparticle

removal down to 0.01removal down to 0.01 mm

Air should be preAir should be pre--filteredfiltered

down to 5down to 5 m to preventm to prevent

short element life due toshort element life due to

solid particle build upsolid particle build up

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Coalescing filter element

Air enters the inside of theAir enters the inside of the

element and passes throughelement and passes through

the filter to the outerthe filter to the outer

surfacesurface

Perforated stainless steelPerforated stainless steel

supporting formers for upsupporting formers for up

to 10 bar differentialto 10 bar differential

Filter media: borosilicateFilter media: borosilicate

glass micro fibreglass micro fibre

Foam sock diffuses air flowFoam sock diffuses air flow

to low velocity to preventto low velocity to prevent

oil reoil re--entrainmententrainment

Ends set in resin to sealEnds set in resin to seal

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Coalescing filter element

Oil aerosol particlesOil aerosol particles

coalesces (join together)coalesces (join together)

when they contact thewhen they contact the

element mediaelement media The pathways throughThe pathways through

the media are so fine andthe media are so fine and

complex that thecomplex that the

particles cannot passparticles cannot pass

through without contactthrough without contact

Oil soaks and drains toOil soaks and drains to

the bottom of the sockthe bottom of the sock

where it drips in to thewhere it drips in to thebowlbowl


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Coalescing filters

Flow ratings are lower thanFlow ratings are lower than

equivalent sized standardequivalent sized standard

units e.g. 28 dm3/sunits e.g. 28 dm3/scompared to 83 dm3/s forcompared to 83 dm3/s for

G1/2 at 6.3 barG1/2 at 6.3 bar

Filter area large for ratedFilter area large for rated

flow to keep air velocity lowflow to keep air velocity low

and prevent oil reand prevent oil re--

entrainmententrainment

Standard service lifeStandard service life

indicator monitors theindicator monitors the

pressure drop to warn whenpressure drop to warn whenelement requires replacingelement requires replacing

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Electrical service life indicator

Ideal for remote indicationIdeal for remote indication

when filter elementwhen filter element

requires replacingrequires replacing Can be used to give remoteCan be used to give remote

visual and audible warningvisual and audible warning

For sensitive applicationsFor sensitive applications

can be used tocan be used to

automatically turn off aautomatically turn off a

machine or processmachine or process

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High efficiency oil removal

High efficiency coalescingelement

Remaining oil content 0.01ppm max at + 21oC

Particle removal down to0.01 m

Air quality to ISO 8573-1Class 1.7.2(to accommodate any oilvapour carry-over that maycondense out at lowertemperatures)

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Ultra high efficiency

Active carbon pack for oilvapour and odour removal

Warning pink dye activatedif oil carries over due tocoalescing element failure

Remaining oil content 0.003ppm max at + 21oC

Particle removal down to0.01 m

Air quality to ISO 8573-1Class 1.7.1


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Coalescing silencers

For the termination of allpneumatic system exhausts

Removes lubricating oilparticles carried over in theexhaust

Large filter area keepsexhaust velocity low for verylow noise

Piped exhausts can beconnected to either end

Can be gang mounted alsowith porting blocks

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Pressure regulator

Reduces supply pressure P1Reduces supply pressure P1

to a suitable workingto a suitable working

pressure P2pressure P2 When there is no flowWhen there is no flow

demand the poppet valvedemand the poppet valve

closes to hold the pressurecloses to hold the pressure

at P2at P2

Flow demand will open theFlow demand will open the

poppet valve wide enoughpoppet valve wide enough

to satisfy the flow rate atto satisfy the flow rate at

pressure P2pressure P2

P2 can be set on a gaugeP2 can be set on a gaugefitted to the regulatorfitted to the regulator

2

4 6

8

10

40

80

120

lbf/in2

bar

P1 P2

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Pressure regulator

Reduces supply pressure P1Reduces supply pressure P1

to a suitable workingto a suitable working


When there is no flowWhen there is no flow

demand the poppet valvedemand the poppet valve

closes to hold the pressurecloses to hold the pressure

at P2at P2

Flow demand will open theFlow demand will open the

poppet valve wide enoughpoppet valve wide enough

to satisfy the flow rate atto satisfy the flow rate at


P2 can be set on a gaugeP2 can be set on a gauge

fitted to the regulatorfitted to the regulator

2

4 6

8

10

4080

120

lbf/in2

bar

P1 P2

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Pressure regulator

To increase pressure P2,To increase pressure P2,

pull the adjusting knob uppull the adjusting knob up

to disengage the lockingto disengage the locking

teethteeth

Turn clockwise until new P2Turn clockwise until new P2

pressure reachedpressure reached

The higher spring forceThe higher spring force

pushes the valve openpushes the valve open

The rising pressure P2 actsThe rising pressure P2 acts

under the diaphragm tounder the diaphragm to

balance the spring andbalance the spring and

allow the valve to closeallow the valve to close

2

4 6

8

10

4080

120

lbf/in2

bar

P1 P2


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Pressure regulator

When the desired pressureWhen the desired pressure

is reached the force on theis reached the force on the

diaphragm will fully balancediaphragm will fully balancethe force on the spring andthe force on the spring and

the valve will closethe valve will close

Dead end applications areDead end applications are

those that are closed ended.those that are closed ended.

The flow demand isThe flow demand is

intermittent so the systemintermittent so the system

will fill and settle at the setwill fill and settle at the set

pressure e.g (a singlepressure e.g (a single

stroke of an actuator)stroke of an actuator)

2

4 6

8

10

4080

120

lbf/in2

bar

P1 P2

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Pressure regulator

While flow is taking placeWhile flow is taking place

the valve will be held openthe valve will be held open

wide enough to keep aswide enough to keep asclose to the set pressure asclose to the set pressure as

possible for the flowpossible for the flow

demanddemand

As the flow rate increasesAs the flow rate increases

so the pressure under theso the pressure under the

diaphragm decreases todiaphragm decreases to

open the valve wider toopen the valve wider to

maintain the flow close tomaintain the flow close to

the set pressurethe set pressure

2

4 6

8

10

4080

120

lbf/in2

bar

P1 P2

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Pressure regulator

This is a relieving regulatorThis is a relieving regulator

to allow pressure to beto allow pressure to be

reduced to a lower settingreduced to a lower setting

Turn anticlockwise toTurn anticlockwise to

reduce the spring forcereduce the spring force

The higher force under theThe higher force under the

diaphragm lifts it clear ofdiaphragm lifts it clear of

the valve spindlethe valve spindle

P2 can now exhaust untilP2 can now exhaust until

the diaphragm sealsthe diaphragm seals

Turn clockwise to adjust upTurn clockwise to adjust up

to the new pressureto the new pressureP1 P2

2

4 6

8

10

4080

120

lbf/in2

bar

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Pressure regulator

Once the desired settingOnce the desired setting

has been established pushhas been established push

down the locking adjustingdown the locking adjusting

knob to prevent inadvertentknob to prevent inadvertent

changeschanges2

4 6

8

10

4080

120

lbf/in2

bar

P1 P2


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Lubricators

There are two main types ofThere are two main types of

lubricatorlubricator

One is the conventionalOne is the conventionalhigh delivery Oil Fog serieshigh delivery Oil Fog series

( coded green)( coded green)

The other is the unique andThe other is the unique and

more widely used Micro Fogmore widely used Micro Fog

range (coded red)range (coded red)

Both types are easilyBoth types are easily

adjusted to preadjusted to pre--set theset the

lubrication densitylubrication density

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Oil fog lubricators

All of the oil drips seen through the sight domeAll of the oil drips seen through the sight dome

enter the air stream and are atomisedenter the air stream and are atomised

The size range of the oil particles produced areThe size range of the oil particles produced areideally suited to lubricating single items ofideally suited to lubricating single items of

equipment on medium to short runs of pipeequipment on medium to short runs of pipe

The oil particles are carried along with the air flow,The oil particles are carried along with the air flow,

and gradually "wet out" to provide adequateand gradually "wet out" to provide adequate

lubrication for applications such as nut runners,lubrication for applications such as nut runners,

screwdrivers and other equipment requiringscrewdrivers and other equipment requiring

heavier lubricationheavier lubrication

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Oil fog lubricator

For lubricating over shortFor lubricating over short

distances where wetdistances where wet--out isout is

required earlyrequired early

Suited for; air tools, airSuited for; air tools, air

motors, single largemotors, single large

cylinders etc.cylinders etc.

Oil drips are broken up inOil drips are broken up in

the main air stream and allthe main air stream and all

particle sizes carried in theparticle sizes carried in the

airair

Drip rate is adjustableDrip rate is adjustable

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Oil fog lubricator

Oil drips visible through theOil drips visible through the

sight dome pushed by thesight dome pushed by the

pressure differencepressure difference

between Pbetween P11 and Pand P22

SyphonSyphon tube with checktube with check

valve to prevent oil drainvalve to prevent oil drain

back when there is no flowback when there is no flow

taking placetaking place

Transparent polycarbonateTransparent polycarbonate

bowl to inspect oil levelbowl to inspect oil level

Alternative metal bowl withAlternative metal bowl with

sight glasssight glass

P1

P2

P1

P2


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Micro-fog lubricator

Oil drips visible through theOil drips visible through the

sight dome pushed by thesight dome pushed by the

pressure differencepressure differencebetween Pbetween P11 and Pand P33

All drips pass through theAll drips pass through the

atomising head. Pressureatomising head. Pressure

drop Pdrop P33 created bycreated by venturiventuri

in atomising headin atomising head

Only smallest lightest 10%Only smallest lightest 10%

oil particles can make theoil particles can make the

tight turn to exit the bowltight turn to exit the bowl

carried by the pressure dropcarried by the pressure dropPP11 : P: P22

P1

P3

P1

P2

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P1

P3

P1

P2

Turn the red control toTurn the red control to

adjust the oil flowadjust the oil flow

restrictionrestriction Observe the drip rateObserve the drip rate

Flexible flow sensor,Flexible flow sensor,

progressively bends flat asprogressively bends flat as

the flow increases. Thisthe flow increases. This

controls the local pressurecontrols the local pressure

drop Pdrop P11 : P: P22 to drawto draw

lubricated air from the bowllubricated air from the bowl

in proportion to flowin proportion to flow

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Due to the high flow in toDue to the high flow in to

the bowl, a microthe bowl, a micro--fogfog

cannot be filled undercannot be filled under

pressurepressure

First turn off and exhaustFirst turn off and exhaust

the air supplythe air supply

Remove the bowl and fillRemove the bowl and fill

Replace bowl securelyReplace bowl securely

Turn on the airTurn on the air

To fill under pressure,To fill under pressure,

replace filler plug with areplace filler plug with a

nipple adaptornipple adaptor

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FRL


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Relief valve

Spring force preventsnormal air pressure from

lifting the diaphragm Excessive pressure will lift

the diaphragm to open thepoppet valve and relieve airto the outlet

When the pressure drops tothe pre-set value again thespring closes the diaphragmpoppet OutIn

82

Relief valve

Spring force preventsnormal air pressure from

lifting the diaphragm Excessive pressure will lift

the diaphragm to open thepoppet valve and relieve airto the outlet

When the pressure drops tothe pre-set value again thespring closes the diaphragmpoppet OutIn

Documents

Applications of Hydraulics&Pneumatics : Session 13