regulating valve
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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
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REGULATING VALVE APPLICATIONS
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.
29428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
BLOWDOWN VALVE ORIENTED ATSAME ELEVATION AS STRAINER PORTSTO AVOID CONDENSATE COLLECTION
BLOWDOWN VALVEBELOW STRAINER PORTS
INLETPORT
OUTLETPORT
DRIP
LEG
STEAMTRAP
DRAIN VALVE
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ENGINEERING
298428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
REGULATING VALVE APPLICATIONS
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.
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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
29428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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
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REGULATING VALVE APPLICATIONS
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.
INSTALLATION GUIDELINES: (see Figure 9)
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
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 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
the complete volume of steam from the regulator and bypass loop. Consult the factory for appropriate SRVsizing guidelines.
300428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
ENGINEERING
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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
REGULATING VALVE APPLICATIONS
PRESSURE REDUCING STATION with AIR-LOADED PILOT for REMOTE INSTALLATIONS
Figure 9:
30428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
STEAM
OUTLET
APPLICATION
DEPENDENT
A
PILOT
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REGULATING VALVE APPLICATIONS
TWO-STAGE (SERIES) PRESSURE REDUCING STATION
302428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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.
INSTALLATION GUIDELINES: (see Figure 10)
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.
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
of the regulator is to keep the steam velocity constant on both sides of the regulator.
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.
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 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
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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
REGULATING VALVE APPLICATIONS
TWO-STAGE (SERIES) PRESSURE REDUCING STATION
Figure 10:
30428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
DRAIN
VALVE
DRAIN
VALVE
HDP
REGULATOR
PRESSURE
SENSINGLINE
DRAIN
VALVE
TWO-STAGE(SERIES)PRESSUREREDUCING
STATION
(HDREGULATORAPPLICATIONS)
2ndStage
1stStage
STEAM
OUTLET
P
PILOT
PPILOT
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REGULATING VALVE APPLICATIONS
PARALLEL PRESSURE REDUCING STATION
304428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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.
Set pressure for each PRV is adjusted by turning a screw on the pilot to increase or decrease compression on abalancing spring.
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
of the regulator is to keep the steam velocity constant on both sides of the regulator.
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 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 shouldregulator 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.
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
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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
REGULATING VALVE APPLICATIONS
PARALLEL PRESSURE REDUCING STATION
Figure 11:
30428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
PARAL
LELPRESSUREREDUCINGSTATION
(HDREGULATORAPPLICATIONS)
Primary
DRAIN
VALVE
DRAIN
VALVEA
PPLICATION
D
EPENDENT
GATE
VALVE
GATE
VALVE
Secondary
PRESSURE
SENSINGLINE
HDP
RE
GULATOR
STEAM
OUTLET
P
PILOT
PPILOT
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REGULATING VALVE APPLICATIONS
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.
INSTALLATION GUIDELINES: (see Figure 12)
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.
Set pressure for each PRV is adjusted by turning a screw on the pilot to increase or decrease compression on abalancing spring.
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
of the regulator is to keep the steam velocity constant on both sides of the regulator.
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 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 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.
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 handle
the complete volume of steam from the regulator and bypass loops. Consult the factory for appropriate SRVsizing guidelines.
428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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REGULATING VALVE APPLICATIONS
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
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REGULATING VALVE APPLICATIONS
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.
INSTALLATION GUIDELINES: (see Figure 13)
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.
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 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.
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 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.
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.
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. Consult the factory for
appropriate SRV sizing guidelines.
308428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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REGULATING VALVE APPLICATIONS
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:
428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
SEPARATOR
DRAIN
VALVE
DRAIN
VALVE
GATEVALVE
STRAINER
ISOLATION
VALVE
STRAINER
ISOLATION
VALVE
TEMP
ERATURE
SENS
INGBULB
PRESSURE
SENSINGLINE
CAPILLARY
T
PILOT
PPILOT
VENT
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ENGINEERING
REGULATING VALVE APPLICATIONS
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.)
INSTALLATION GUIDELINES: (see Figure 14)
The temperature and pressure pilots should be set individually, starting slowly and gradually with the T-pilot.
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 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.
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 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.
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.
310428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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REGULATING VALVE APPLICATIONS
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:
31428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
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
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312428 Jones Boulevard Limerick Airport Business Center Pottstown PA 19464 Tel: 610-495-5131 Fax: 610-495-5134
www.watsonmcdaniel.com
REGULATING VALVE APPLICATIONS
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.
INSTALLATION GUIDELINES: (see Figure 15)
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.
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
of the regulator is to keep the steam velocity constant on both sides of the regulator.
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.
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.
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.
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 handle
the complete volume of steam from the regulator and bypass loop. Consult the factory for appropriate SRVsizing guidelines.
ENGINEERING
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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
REGULATING VALVE APPLICATIONS
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
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