regulating valve

7/25/2019 Regulating Valve

1/18

Regulator Application & Installation Notes

The following are considerations for all steam regulator installations, as system operation is dependent uponproper design, installation, start-up and maintenance procedures:

REGULATING VALVE APPLICATIONS

GENERAL REGULATOR APPLICATION & INSTALLATION NOTES

ENGINEERING

296428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134

www.watsonmcdaniel.com

Inlet & Outlet Pipe Sizing

Improperly sized piping can contribute to erraticcontrol and excessive noise in a steam system.Make certain inlet and outlet piping to the regulatoris adequately sized for the flow, velocity andpressure requirements.

RULE OF THUMB:Inlet piping is typically 1-2 sizes larger and outletpiping 2-3 sizes larger than the connection portsof a properly sized regulator.

Straight Run of Pipe Before and After the Valve

Pipe fittings, bends and other accessories contributeto fluid turbulence in a system which can result inerratic control. To limit this and ensure optimumsystem operation, follow recommended guidelinesfor minimum straight run lengths of pipe before andafter a regulator.

Note: Any isolation valves or pipeline accessoriesshould be full-ported.

Reducer Selection

Concentric pipe reducers should be avoidedon the inlet side of regulators as they can allowentrained condensate to collect, potentially

leading to damaging and dangerous waterhammer.Therefore, when reducers are required in the steampiping to accommodate properly sized valves andpipes, use eccentric reducers on regulator inletsand concentric or eccentric reducers on regulatoroutlets.

10 PIPEDIAMETERS

MINIMUM

10 PIPEDIAMETERS

MINIMUM

1-2 SIZESLARGER THANREGULATORINLET PORT

2-3 SIZESLARGER THANREGULATOR

OUTLET PORT

CONCENTRIC REDUCER

ECCENTRIC REDUCER

STEAM

STEAM

CONDENSATEACCUMULATED ATLOW POINT

REGULATOR


2/18


GENERAL REGULATOR APPLICATION & INSTALLATION NOTES

Strainers with Blowdown Valves

Regardless of any filters provided on a regulator, astrainer with blowdown valve is recommended before(upstream of) all regulator installations. Pipeline

debris and scale can damage internal valvecomponents, potentially leading to poor operationand/or failure.

Note: Consider strainer orientation to avoidcollection of condensate (see diagram).

Drip Legs & Steam Traps

To prevent condensate accumulated duringshutdown from possibly damaging the regulator orpiping at start-up, an adequately sized drip leg withsteam trap should be installed prior to all regulators.This will also help protect the regulator duringnormal operation.

Note: Separators may be necessary when boilercarryover or wet steam is a concern.

Proper Start-up & Maintenance Procedures

It is important to follow good start-up practicesto avoid operational complications and potentialsystem damage. Starting a steam system tooquickly or using an improper sequence may lead

to a potentially hazardous working environment.Lack of system maintenance over time can alsocontribute to this situation.

It is imperative to develop proper start-up andmaintenance procedures and train personnel onthe importance of following them at all times.

Consult equipment manufacturers for specificguidelines, if necessary.



BLOWDOWN VALVE ORIENTED ATSAME ELEVATION AS STRAINER PORTSTO AVOID CONDENSATE COLLECTION

BLOWDOWN VALVEBELOW STRAINER PORTS

INLETPORT

OUTLETPORT

DRIP

LEG

STEAMTRAP

DRAIN VALVE


3/18

ENGINEERING




SINGLE STAGE PRESSURE REDUCING STATION USING SPRING-LOADED PILOT

PURPOSE: For reducing system inlet pressure to a constant outlet pressure.

OPERATION: The pressure reducing valve (PRV) can be easily adjusted to set the desired outlet pressure and

modulates to maintain that pressure setting. The PRV requires no external power source.

INSTALLATION GUIDELINES: (see Figure 8)

This example depicts a pilot-operated steam PRV, whereby an external sensing line is required to sensedownstream pressure. The end of the sensing line is placed away from the turbulent flow of the valve outlet.This helps to improve accuracy of the set pressure. Set pressure is adjusted by turning a screw on the pilot

to increase or decrease compression on a balancing spring.

For optimum operation and service life, maintain recommended minimum piping straight runs before andafter the PRV. Inlet pipe diameters are typically 1-2 sizes larger and outlet pipe diameters 2-3 sizes larger

than the end connections of an appropriately sized PRV. The purpose of increasing the pipe size downstream

of the regulator is to keep the steam velocity constant on both sides of the regulator.

The pressure sensing line should slope downwards, away from the regulator, to prevent condensate from

entering the pilot.

Eccentric reducers are used on valve inlets to prevent accumulation of pipeline moisture which could becomeentrained with high-velocity steam, possibly resulting in dangerous waterhammer.

While the separator shown upstream is appropriate for protection of the PRV, it is not always required as a

properly sized drip leg with steam trap may be sufficient. It is recommended for systems where steam is knownto be wet and the entrained moisture could affect valve performance and/or result in component damage.

Consider installing a properly sized bypass line with globe valve to provide continuous operation should

regulator maintenance be required.

Consider low-cracking pressure (1/4 PSI opening pressure) check valves after steam traps when discharginginto condensate return lines. Check valves eliminate the possibility of condensate backing up through the

steam trap into the system.

A safety relief valve (SRV) is appropriate where applicable codes dictate their requirement, or anywhereprotection of downstream piping and equipment from over-pressurization is desired. The SRV needs to handle

the complete volume of steam from the regulator and bypass loop. Consult the factory for appropriate SRVsizing guidelines.


4/18

SIN

GLESTAGEPRESSUREREDUCINGSTATIONUSING

SPRING-LOADEDPILOT

(HDREGULATORAPPLICATIONS

)

GATE

VALVE

STEAM

TRAP

DRIP

PAN

ELBOW

ISOLATION

VALVE

CHEC

K

VALV

E

IS

OLATION

VALVE

CHECK

VALVE

ISOLATION

VALVE

STEAM

TRAP

GATE

VALVE

ISOLATION

VALVE

ISOLATION

VALVE

CHECK

VALVE

ISOLATION

VALVE

STEAM

TRAP

STRAINER

STRAINER

STRAINER

HDPREG

ULATOR

VENT

S

RV

STEAM

INLET

SEPARATO

R

APPLICATION

DEPENDENT

PRESSURE

SENSING

LINE

STRAINER

10PIPE

DIAMETERSMINIMUM

BYPASS

GLOBE

VALVE

10PIPE

DIAMETERSMINIMUM

TOCONDEN

SATE

RETURN

TOCONDENSATE

RETURN

TO

CONDENSATE

RETURN



REGULATING VALVE APPLICATION

SINGLE STAGE PRESSURE REDUCING STATION USING SPRING-LOADED PILO

DRAIN

VALVE

ECCENTRIC

REDUCER

CONCENTRIC

REDUC

ER

Figure 8:

DRAIN

VALVE

STEAM

OUTLET


5/18


PRESSURE REDUCING STATION with AIR-LOADED PILOT for REMOTE INSTALLATIONS

PURPOSE: For reducing system inlet pressure to a constant outlet pressure when valve is located in a remotelocation and/or using air pressure for control is desired.

OPERATION: This combination of HD regulating valve and A-pilot (HDA) allows air to be used to control outletpressure in lieu of the spring of a standard P-pilot. Using air allows for simple adjustment of controlpressure when valve is installed in a remote and/or difficult to access location.


The desired set outlet pressure will determine the specific A-Pilot required as well as the air supply pressureto attain the set pressure. Consult the appropriate section of this catalog or the factory for selection guidelines.

For optimum operation and service life, maintain recommended minimum piping straight runs before and

after the PRV. Inlet pipe diameters are typically 1-2 sizes larger and outlet pipe diameters 2-3 sizes largerthan the end connections of an appropriately sized PRV. The purpose of increasing the pipe size downstream


The pressure sensing line should slope downwards, away from the regulator, to prevent condensate fromentering the pilot.

Eccentric reducers are used on valve inlets to prevent accumulation of pipeline moisture which could become

entrained with high-velocity steam, possibly resulting in dangerous waterhammer.

While the separator shown upstream is appropriate for protection of the PRV, it is not always required, as aproperly sized drip leg with steam trap may be sufficient. It is recommended for systems where steam is knownto be wet and the entrained moisture could affect valve performance and/or result in component damage.

Consider installing a properly sized bypass line with globe valve to provide continuous operation shouldregulator maintenance be required.

Consider low-cracking pressure (1/4 PSI opening pressure) check valves after steam traps when discharging

into condensate return lines. Check valves eliminate the possibility of condensate backing up through thesteam trap into the system.

A safety relief valve (SRV) is appropriate where applicable codes dictate their requirement, or anywhereprotection of downstream piping and equipment from over-pressurization is desired. The SRV needs to handle




ENGINEERING


6/18

PRESSU

REREDUCINGSTATIONw

ithAIR-LOADEDPILOTforREMOTEINSTALLATIONS

(HDREGULATORAPPLICATIONS)

SEPARATOR

TOCONDEN

SATE

RETURN

HDA

REGULA

TOR

CHECK

VALVE

STEAM

INLET

CHECK

VALVE

CHECK

VALVE

ISOLATION

VALVE

IS

OLATION

VALVE

ISOLATION

VALVE

ISOLATION

VAL

VE

STEAM

TRAP

STEAM

TRAP

ISOLATION

VALVE

ISOLATION

VALVE

STRAINER

STRAINER

STRAINER

GATE

VALVE

GATE

VALVE

DRIP

PAN

ELBOW

DRAIN

VALVE

DRAIN

VALVE

VENT

S

RV

BYPASS

GLOBE

VALVE

10PIPE

DIA

METERSMINIMUM

10PIPE

DIAM

ETERSMINIMUM

PL2

AIRSUPPLY

CONTROL

AIRLINE

STEAM

TRAP

STR

AINER

TO

CONDENSATE

RETURN

TOCONDENSATE

RETURN

PRESSURE

SENSINGLINE

AIR

REGULATOR


PRESSURE REDUCING STATION with AIR-LOADED PILOT for REMOTE INSTALLATIONS

Figure 9:



STEAM

OUTLET

APPLICATION

DEPENDENT

A

PILOT


7/18


TWO-STAGE (SERIES) PRESSURE REDUCING STATION



PURPOSE: For reducing system inlet pressure to a constant outlet pressure when the pressure drop exceedsthe recommended operation of a single-stage pressure regulating valve (PRV).

OPERATION: The 1st stage PRV reduces inlet pressure to an intermediate pressure. The 2nd stage PRV thenreduces pressure to the final outlet pressure. Individual valve setting and operation is the sameas for single-stage applications.


This example depicts a two-stage (series) pilot-operated steam PRV pressure reducing station using HDP regulatorsAn external sensing line is required to sense downstream pressure from each regulator. The end of each sensingline is placed away from the turbulent flow at the valve outlet. This helps to improve accuracy of the set pressures.

Set pressure for each PRV is adjusted by turning a screw on the pilot to increase or decrease compression on abalancing spring.




Each pressure sensing line should slope downwards, away from the regulator, to prevent condensate fromentering the pilot.

Eccentric reducers are used on valve inlets to prevent accumulation of pipeline moisture which could become

entrained with high-velocity steam, possibly resulting in dangerous waterhammer.

While the separator shown upstream is appropriate for protection of the PRV, it is not always required, as aproperly sized drip leg with steam trap may be sufficient. It is recommended for systems where steam is known

to be wet and the entrained moisture could affect valve performance and/or result in component damage.

Consider installing a properly sized bypass line with globe valve on each stage, to provide continuous operationshould regulator maintenance be required.



A safety relief valve (SRV) is appropriate where applicable codes dictate their requirement, or anywhere

protection of downstream piping and equipment from over-pressurization is desired. The SRV needs to handlethe complete volume of steam from the regulator and bypass loop. Consult the factory for appropriate SRVsizing guidelines.

ENGINEERING


8/18

STEAM

TRAP

DRIP

PAN

ELBOW

STEAM

TRAP

VENT

SRV

SEPARATOR

APPLICATION

DEPENDENT

BYPASS

GLOBE

VALVE

GATE

VALVE

STEAM

TRAP

ISOLATION

VALVE

CHECK

VALVE

GATE

VALVE

GATE

VALVE

STRAINER

PRESSURE

SENSING

LINE

GATE

VALVE

STRAINER S

TEAM

TRAP

TO

CONDENSATE

RETURN

ISOLATIO

N

VALVE

BYPASS

GLOBE

VALVE

STEAM

INLET

TOCONDENSATE

RETURN

TOCONDENSATE

RETURN

HDP

REGULATOR1

0PIPE

DIAMETERS

MINIMUM

10PIPE

DIAMETERS

MINIMUM

10PIPE

DIAMETERS

MINIMUM

20PIPE

DIAMETERSMINIMUM


TWO-STAGE (SERIES) PRESSURE REDUCING STATION

Figure 10:



DRAIN

VALVE

DRAIN

VALVE

HDP

REGULATOR

PRESSURE

SENSINGLINE

DRAIN

VALVE

TWO-STAGE(SERIES)PRESSUREREDUCING

STATION


2ndStage

1stStage

STEAM

OUTLET

P

PILOT

PPILOT


9/18


PARALLEL PRESSURE REDUCING STATION



PURPOSE: For reducing system inlet pressure to a constant outlet pressure when steam flow rates vary widely.

OPERATION: Typically referred to as 1/3 - 2/3 system, one valve may be sized for 1/3 of the total load demand

and the other for 2/3. When full load is required, both valves will be open and regulating. The primaryvalve is set at a pressure 2 PSI higher than the secondary valve to allow the secondary valve set atthe lower pressure to modulate closed when flow demand is reduced and outlet pressure begins to

rise. The primary valve may be selected as either the larger or smaller PRV, based on expectedload demands.

INSTALLATION GUIDELINES (see Figure 11)

This example depicts a parallel pilot-operated steam PRV pressure reducing station using HDP regulators.

An external sensing line is required to sense downstream pressure from each regulator. The end of each sensingline is placed away from the turbulent flow at the valve outlet. This helps to improve accuracy of the set pressures.


Proper setting of the valves is key to proper operation. The chosen primary valve should be set at a pressure

approximately 2 PSI higher than that of the secondary valve.

For optimum operation and service life, maintain recommended minimum piping straight runs before andafter the PRV. Inlet pipe diameters are typically 1-2 sizes larger and outlet pipe diameters 2-3 sizes largerthan the end connections of an appropriately sized PRV. The purpose of increasing the pipe size downstream




While the separator shown upstream is appropriate for protection of the PRV, it is not always required, as a



Consider low-cracking pressure (1/4 PSI opening pressure) check valves after steam traps when discharginginto condensate return lines. Check valves eliminate the possibility of condensate backing up through thesteam trap into the system.

A safety relief valve (SRV) is appropriate where applicable codes dictate their requirement, or anywhereprotection of downstream piping and equipment from over-pressurization is desired. The SRV needs to handlethe complete volume of steam from the regulator and bypass loop. Consult the factory for appropriate SRV

sizing guidelines.

ENGINEERING


10/18

VENT

SRV

DRIP

PAN

ELBOW

10PIPE

DIAMETERSMINIMUM

10PIPE

DIAMETERSMINIMUM

A

PPLICATION

D

EPENDENT

S

EPARATOR

GATE

VALVE

STEAM

TRAP

ISOLATION

VALVE

CH

ECK

VALVE

STEAM

TRAP

TOCONDENSATE

RETURN

TO

CONDENSATE

RETURN

TOCONDENS

ATE

RETURN

ISOLATION

VALVE

STRAINER

STEAM

TRAP

GATE

VALVE

BYPASS

GLOBE

VALVE

ISOLATION

VA

LVE

CHECK

VALVE

TOCONDENSATE

RETURN

SEPARATOR

HDPREGULATOR

STEAM

INLET

ISOLATION

VALVE

STRAINER

STEAM

TRAP

PRESSURE

SENSINGLINE

STRAINER

STRAINER


PARALLEL PRESSURE REDUCING STATION

Figure 11:



PARAL

LELPRESSUREREDUCINGSTATION


Primary

DRAIN

VALVE

DRAIN

VALVEA

PPLICATION

D

EPENDENT

GATE

VALVE

GATE

VALVE

Secondary

PRESSURE

SENSINGLINE

HDP

RE

GULATOR

STEAM

OUTLET

P

PILOT

PPILOT


11/18


TWO-STAGE PARALLEL PRESSURE REDUCING STATION

306

ENGINEERING

PURPOSE: For reducing system inlet pressure to a constant outlet pressure when both flow conditions vary

widely and a high pressure drop (i.e. higher than the recommended range of a single stage regulator)is required.

OPERATION: This system is a combination of Two-Stage (Series) and Parallel pressure reducing stations and

operates based on the individual principles of each system. This allows for accurate control of outletpressure when both high pressure and high flow turndowns are required.


This example depicts a two-stage parallel pilot-operated steam PRV pressure reducing station using HDP regulators

An external sensing line is required to sense downstream pressure from each regulator. The end of each sensingline is placed away from the turbulent flow at the valve outlet. This helps to improve accuracy of the set pressures.


Proper setting of the valves is key to proper operation. The chosen 1st stage primary valve should be set at a

pressure approximately 2 PSI higher than that of the 1st stage secondary valve.

For optimum operation and service life, maintain recommended minimum piping straight runs before andafter the PRV. Inlet pipe diameters are typically 1-2 sizes larger and outlet pipe diameters 2-3 sizes largerthan the end connections of an appropriately sized PRV. The purpose of increasing the pipe size downstream






Consider installing a properly sized bypass line with globe valve on each stage, to provide continuous operationshould regulator maintenance be required.

Consider low-cracking pressure (1/4 PSI opening pressure) check valves after steam traps when discharginginto condensate return lines. Check valves eliminate the possibility of condensate backing up through thesteam trap into the system.


protection of downstream piping and equipment from over-pressurization is desired. The SRV needs to handle

the complete volume of steam from the regulator and bypass loops. Consult the factory for appropriate SRVsizing guidelines.




12/18


TWO-STAGE PARALLEL PRESSURE REDUCING STATION

30

VENT

SRV

DRIP

PAN

ELBOW

10PIPE

DIAMETERS

MINIMUM

APPLICATION

DEPENDENT

STEAM

TRAP

TOCONDENSATE

RETURN

STEAM

TRAP

BYPASS

GLOBE

VALVE

SEPARATOR

STEAM

INLET

BYPASS

GLOBEVALVE

SEPARATOR

STEAM

TRAP

STEAM

TRAP

ISOLATION

VALVE

CHECK

VALVE

ISOLATION

VALVE

10PIPE

DIAMETERS

MINIMUM

GATE

VALVE

HDP

REGULATO

R

GATE

VALVE

GATE

VALVE

GA

TE

VALVE

GATE

VALVE

GATE

VALVE

STEAM

TRAP

GATE

VALVE

GA

TE

VALVE

20PIPE

DIAMETER

S

MINIMUM

TO

CONDENSATE

RETURN

Figure 12:

2ndStage

1stStage

T W O S T A G E P A R A L L E L P R E S S U R E R E D U C I N G

S T A T I O NPR

ESSURE

SENSINGLINE

PRESSURE

SENSINGLINE

Primary

Secondary

PRESSURE

SENSINGLINE

PRESSURE

SENSINGLINE

STRAINER

HDP

REGULATOR

STRAINER

HDP

REGULATOR

TOCONDENSATE

RETURN

HDP

REGULA

TOR

TOCONDENSATE

RETURN

DRAIN

VALVE

DRAIN

VALVE

STRAINER

DRAIN

VALVE

STEAM

OUTLET

PP

ILOT

P

PILOT


13/18


TEMPERATURE CONTROL of a HEAT EXCHANGER with PRESSURE LIMITING

ENGINEERING

PURPOSE: For accurately controlling both temperature of a product being heated in heat transfer equipmentas well as limiting the pressure of the incoming steam, providing optimum heat transfer characteristics

OPERATION: When a pilot-operated HD valve is selected, a single valve can be used for both pressure and

temperature control when equipped with a P-pilot and T-pilot (HDPT). As temperature at the sensingbulb falls below set point, the valve begins to modulate open to supply steam for heating. Supply

pressure to the heat exchanger is then controlled by adjusting the pressure pilot to the recommendedvalue for optimum heat transfer and/or a limiting pressure of the heat transfer equipment. The HDPT

Regulator requires no external power source.


The temperature and pressure pilots should be set individually, starting slowly and gradually with the T-pilot.

Care should be given to the installation of the temperature sensing bulb to ensure full immersion in the liquid.The sensing bulb should be placed as close as possible to the heat exchanger vessel to ensure accurate

temperature control of the process fluid.


than the end connections of an appropriately sized PRV. The purpose of increasing the pipe size downstreamof the regulator is to keep the steam velocity constant on both sides of the regulator.

The pressure sensing line should slope downwards, away from the regulator, to prevent condensate from

entering the pilot.

Eccentric reducers, if required, are used on valve inlets to prevent accumulation of pipeline moisture which couldbecome entrained with high-velocity steam, possibly resulting in dangerous waterhammer.





The vacuum breaker and auxiliary air vent located at the top of the heat exchanger vessel promotes proper

drainage and optimum heat transfer. The vacuum breaker allows system equalization with atmospheric air toallow gravity condensate drainage when vacuum is formed from condensing steam. The air vent improvesheat-up times and overall heat transfer by expelling accumulated air on start-up.


protection of downstream piping and equipment from over-pressurization is desired. Consult the factory for

appropriate SRV sizing guidelines.




14/18


TEMPERATURE CONTROL of a HEAT EXCHANGER with PRESSURE LIMITING

30

APPLICATION

DEPENDENT

F&TTRAP

F&T

TRAP

HEAT

EXCHANGER

HDPT

REGU

LATOR

COLDWATER

INLETS

RV

DRIPPAN

ELBOW

AV2000

AIR

VENT

HOT

WATER

OUT

LET

WVBSS

VACUUM

BREAKER

STEAM

SUPPLY

TE

MPERATURECONTROLofaHEATEXCHANGERwith

PRESSURELIMITING

(HDRE

GULATORAPPLICATIONS)

Figure 13:



SEPARATOR

DRAIN

VALVE

DRAIN

VALVE

GATEVALVE

STRAINER

ISOLATION

VALVE

STRAINER

ISOLATION

VALVE

TEMP

ERATURE

SENS

INGBULB

PRESSURE

SENSINGLINE

CAPILLARY

T

PILOT

PPILOT

VENT


15/18

ENGINEERING


AUTOMATIC TEMPERATURE CONTROL of a BATCH PROCESSwith Electrical Time Sequence Programmer (Solenoid Pilot)

PURPOSE: For accurately controlling temperature of a batch process where on-off operation is to be

electronically controlled.

OPERATION: Operation is similar to that of the pressure and temperature combination pilot-operated regulator

whereby the temperature (T) pilot senses the temperature inside the autoclave and appropriatelymodulates the flow of steam. Pressure is limited by the pressure (P) pilot. The solenoid valve

(S-pilot) is electronically activated to control on-off operation of the batch process. (The HD Regulatoroperating with these three pilots is known as the HDPTS Regulator.)


The temperature and pressure pilots should be set individually, starting slowly and gradually with the T-pilot.


than the end connections of an appropriately sized PRV. The purpose of increasing the pipe size downstreamof the regulator is to keep the steam velocity constant on both sides of the regulator.

The pressure sensing line should slope downwards, away from the regulator, to prevent condensate fromentering the pilot.

Eccentric reducers, if required, are used on valve inlets to prevent accumulation of pipeline moisture which could

become entrained with high-velocity steam, possibly resulting in dangerous waterhammer.





The thermostatic air vent located at the top of the autoclave chamber promotes optimum heat transfer.The air vent improves heat-up times and overall heat transfer by expelling accumulated air on start-up.

A safety relief valve (SRV) is appropriate where applicable codes dictate their requirement, or anywhereprotection of downstream piping and equipment from over-pressurization is desired. Consult the factory for

appropriate SRV sizing guidelines.




16/18


AUTOMATIC TEMPERATURE CONTROL of a BATCH PROCESSwith Electrical Time Sequence Programmer (Solenoid Pilot)

AUTOMATICTEMPERATURE

CONTROLofaBATCHP

ROCESSwithElectricalTimeSequenceProgrammer(Soleno

idPilot)

(HDREGU

LATORAPPLICATIONS)

TO

CONDENSATE

RETURN

F&T

TRAP

F&T

TRAP

SEPARATOR

HDPTS

REGULATOR

SRV

DRIP

PAN

ELBOW

STEAM

FILTER

TODRAIN

AUTOCLAVE

TH

ERMOSTATIC

AIRVENT

THERMOSTATIC

STEAM

TRAP

POWER

ELECTRIC

OPERATOR

F&T

TRAP

STEAM

SUPPLY

Figure 14:



TO

CONDENSATE

RE

TURN

DRAIN

VALVE

G

ATE

V

ALVE

STRAINER

ISOLATION

VALVE

DRAIN

VALVE

APPLICAT

ION

DEPENDE

NT

CAPILLARY

PRESSURE

SENSING

LINE

TPILOT

PPILOT

TEMPERATURE

SENSINGBULB

VENT

GATE

VALVE

TOCONDENSATE

RETURN

ISOLATION

VALVE

STRAINER

SPILOT

CHECK

VALVE


17/18




TEMPERATURE CONTROL of a SEMI-INSTANTANEOUS HEATER using aSelf-Contained Temperature Regulating Valve

PURPOSE: For accurate control of the temperature of a product being heated when the benefits of a

self-contained regulator are required.

OPERATION:A self-contained temperature regulating valve (TRV) such as the W91, offers response times andcharacteristics suitable for semi-instantaneous heating applications. The temperature sensing bulb

senses the temperature of the liquid being heated and allows modulation of the valve for appropriatesupply of steam.


Care should be given to the installation of the temperature sensing bulb to ensure full immersion in the liquid.

The sensing bulb should be placed as close as possible to the heater tank to ensure accurate temperaturecontrol of the process fluid.




All pressure sensing lines should slope downwards, away from the regulator, to prevent condensate fromentering the pilot.

Eccentric reducers, if required, are used on valve inlets to prevent accumulation of pipeline moisture which could

become entrained with high-velocity steam, possibly resulting in dangerous waterhammer.

While the separator shown upstream is appropriate for protection of the PRV, it is not always required, as aproperly sized drip leg with steam trap may be sufficient. It is recommended for systems where steam is known

to be wet and the entrained moisture could affect valve performance and/or result in component damage.




The vacuum breaker and auxiliary air vent located at the top of the heater tank promotes proper drainageand optimum heat transfer. The vacuum breaker allows system equalization with atmospheric air to allow

gravity condensate drainage when vacuum is formed from condensing steam. The air vent improves heat-uptimes and overall heat transfer by expelling accumulated air on start-up.


protection of downstream piping and equipment from over-pressurization is desired. The SRV needs to handle


ENGINEERING


18/18

SEMI-INSTANTANEOUSHOTWATE

RHEATERWITHW91TEM

PERATUREREGULATOR

(TEMPERATUR

EREGULATORAPPLICATIONS)

ISOLA

TION

VALVE

TO

CONDENSATE

RE

TURN

SEPARATOR

BYPASSLINE

HOT

WATER

OUTLET

SEMI-INSTANTANE

OUS

HEATER

APPLICATION

DEPENDENT

COLD

WATER

INLE

T

ISOLATION

VALVE

CHECK

VALVE

STEAM

INLET

STEAM

TRAP

STRAINER

W91

TEMPERATURE

REGULATING

VALVE

CAPILLARY

TEMPERATURE

SENSING

BULB

STEAM

TRAP

3428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610 495 5131 Fax: 610 495 5134


TEMPERATURE CONTROL of a SEMI-INSTANTANEOUS HEATER using aSelf-Contained Temperature Regulating Valve

Figure 15:

STRAINER

GLOBE

VALVE

GATE

VALVE

GATE

VALVE

TO

CONDENSATE

RETURN

DRAIN

VALVE

AV2000

AIRVENT

WVBSS

VACUUM

BREAKER

regulating valve

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