ALFACOM ENGINEERING LTD.
Pressure Regulators
Pressure regulators reduce, maintain or control pressure in steam and other process systems, according to the selected model. Explore direct-acting and pilot-operated pressure reduction, back-pressure control and specialised regulator families.
Pressure Regulators · Illustrative catalogue image
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ADCA PRV47 Pilot-Operated Pressure Reducing Valves
Pilot-operated valves for controlling downstream pressure in saturated-steam, compressed-air and compatible Group 2 gas duties, excluding oxygen. The hosted document covers DN15–DN50, with threaded, flanged and socket-weld connection arrangements.
- PRV47 / PRV47i: steel / stainless steel steam versions.
- PRV47G / PRV47Gi: steel / stainless steel air and gas versions.
- Suffix E: version with a solenoid valve for remote closure.
- PRS versions use a sustaining-valve pilot and require separate selection.
Specify inlet pressure and temperature, required outlet pressure, flow range, medium and connections. Select the spring, diaphragm and exact variant from the model's capacity and limiting-condition tables; the standard, E and low-pressure arrangements have different restrictions.
The document specifies horizontal installation. For steam duty it calls for upstream straining, moisture separation and condensate drainage; design the station and sensing line to the installation instructions.
Model & Technical Document Index
Select the equipment family and model below. Review the application and model-specific document before requesting selection and a quotation.
Pressure Reducing Valves & Accessories
Self-Operated Pressure Regulators
Low-Flow Regulators & Pilots
High-Accuracy Pressure Reducing Valves
Diaphragm & Piston-Sensing Reducing Valves
Equipment Details & Selection
Pressure Reducing Valves & Accessories
PRV25/2S · DN15–25
Direct-acting carbon steel pressure reducing valve for compatible steam, air and liquid duties.
Confirm inlet pressure, required downstream pressure, flow and connection. Suitability depends on the actual fluid, temperature and construction.
PRV25I · DN15–25
Direct-acting stainless steel pressure reducing valve for compatible steam, compressed air and liquid services.
Select the pressure range and connection for the required point-of-use duty. Check fluid compatibility and the model-specific operating limits.
PRV47/2 · DN65–100
Pilot-operated pressure reducing valve for steam and compatible gases, for larger pressure-reduction stations.
Specify minimum, normal and maximum flows, inlet-pressure variation and downstream set pressure. Confirm the pilot, main valve and sensing-line arrangement together.
PRV57 · DN15–100
Pilot-operated pressure reducing valve for steam and compatible gas duties with varying inlet pressure or demand.
Use the sizing data for the selected body and pilot. Include upstream pressure, target downstream pressure and the complete flow range.
RP45 · EN-flanged · DN15–150
Self-operated bellows-sealed pressure reducing regulator for compatible steam and gas services.
This record covers the EN-flanged family. Confirm body, actuator, spring range, feedback line and any required water-seal pot as an assembly.
RP45 · ASME-flanged · 1/2–6 inch
Self-operated bellows-sealed pressure reducing regulator for compatible steam and gas duties.
Use the ASME-flanged family document for the required connection. Confirm actuator protection, sensing-line installation and the selected pressure range.
RP45 · Threaded · 1/2–2 inch
Self-operated bellows-sealed pressure reducing regulator with threaded connections.
Select the regulator, actuator and spring range for the actual fluid and pressure conditions. Check the sensing-line and water-seal requirements for hot service.
POT · Water-Seal Pot for RP45
Water-seal pot intended to protect the pressure regulator actuator diaphragm when the process temperature exceeds its permitted temperature.
This is an actuator-protection accessory. Specify it with the RP45 regulator and follow the sensing-line and installation instructions.
Self-Operated Pressure Regulators
RP4 · Pressure Regulating Valve
Self-operated pressure regulating valve for water and other compatible liquids, using an externally piped pilot arrangement.
Confirm whether the required function is pressure reduction or pressure sustaining. Select the pilot, sensing points and main valve for that specific function.
RP6 · Pressure Regulating Valve
Self-operated balanced-plug pressure regulating valve for compatible gas or liquid duties, with an externally piped pilot.
State whether downstream pressure reduction or upstream pressure sustaining is required. Pilot selection and sensing-line arrangement determine the control function.
Low-Flow Regulators & Pilots
P20P · Piston-Sensing Regulator
Spring-loaded direct-acting regulator for low-flow pressure reduction in compatible air, gas and liquid systems.
A piston-sensing design intended for duties such as instrumentation. Specify inlet pressure, outlet range, fluid and the minimum required flow.
P20D · Diaphragm-Sensing Regulator
Direct-acting balanced-plug regulator for compatible air, water, gas and liquid duties at smaller loads.
It can also serve as a pilot with other regulators. Confirm whether a stand-alone regulator or pilot arrangement is required.
P20DS · Diaphragm-Sensing Regulator
Direct-acting regulator for compatible steam, compressed air and other fluid duties at smaller loads.
Pilot applications are also described in the source. Confirm the intended control function, sensing arrangement and fluid compatibility.
P7 · Low-Flow Regulator
Direct-acting diaphragm-sensing pressure reducing valve for steam and compatible gases at very small loads.
The source also covers use as a pilot with other regulators. Select the spring range and connection for the required duty.
High-Accuracy Pressure Reducing Valves
PRV300SS · DN15–20
Direct-acting diaphragm-sensing, balanced-plug regulator for pressure reduction in compatible air, water, gas and liquid systems.
Use the DN15–20 document for the selected size. Define the acceptable downstream-pressure variation and the complete flow range when requesting sizing.
PRV300SS · DN25–32
Direct-acting balanced-plug pressure reducing family for duties requiring accurate downstream pressure control.
Use the DN25–32 document and verify fluid compatibility, spring range and actual flow conditions. Performance must be assessed for the specified duty.
PRV300SS · DN40–50
Direct-acting diaphragm-sensing pressure reducing family for compatible air, water, gas and liquid services.
Use the DN40–50 dimensions and sizing data. Include inlet-pressure variation and the full flow range when specifying pressure-control requirements.
Diaphragm & Piston-Sensing Reducing Valves
PRV30SS · DN15–20
Direct-acting diaphragm-sensing, balanced-plug pressure reducing regulator for compatible air, water, gas and liquid duties.
Use the DN15–20 model document. Select the spring range and confirm pressure-temperature limits for the actual connection and fluid.
PRV30SS · DN25–32
Diaphragm-sensing pressure reducing regulator in the PRV30 family.
Use the DN25–32 model document for dimensions and sizing. Confirm fluid compatibility, outlet range and flow before selection.
PRV30SS · DN40–50
Direct-acting diaphragm-sensing, balanced-plug regulator for compatible air, water, gas and liquid services.
This record covers DN40–50. Use its model-specific dimensions and sizing data rather than extrapolating from the smaller bodies.
PRV31SS · DN15–20
Direct-acting piston-sensing pressure reducing regulator in the PRV31 family.
Use the DN15–20 document. Confirm the required pressure range, fluid, connection and operating temperature for the selected construction.
PRV31SS · DN25–32
Direct-acting piston-sensing, balanced-valve pressure reducing regulator for compatible air, water, gas and liquid duties.
Use the DN25–32 sizing and dimensional data. Specify inlet pressure, downstream set pressure and flow range.
PRV31SS · DN40–50
Piston-sensing pressure reducing regulator in the PRV31 family.
Use the DN40–50 document for the selected body and connection. Confirm actual operating conditions and material compatibility.
PRV41SS · DN10–15
Direct-acting piston-sensing, balanced-plug pressure reducing regulator for compatible air, water, gas and liquid duties.
Use the PRV41-specific pressure range, connection and dimensional data. Supply inlet pressure, required downstream pressure and the flow range for selection.
Pressure Sustaining Valves
PS4 · Direct-Acting Pressure Sustaining Valve
Diaphragm-sensing regulator intended to control upstream pressure in compatible air, water, gas or liquid duties at small loads.
It can also be used as a pilot in an appropriate regulating assembly. State the required upstream pressure and discharge conditions.
PS7 · Low-Flow Pressure Sustaining Valve
Direct-acting diaphragm-sensing valve for upstream pressure control in steam and compatible gas duties at very small loads.
Pilot use with other regulators is also described. Confirm the required control function and upstream set pressure.
PS30SS · Pressure Sustaining Valve
Direct-acting diaphragm-sensing pressure sustaining valve for compatible air, water, gas and liquid duties.
Select it for upstream pressure control. Provide the upstream set pressure, downstream conditions and flow range.
PS31SS · Pressure Sustaining Valve
Direct-acting piston-sensing pressure sustaining valve for compatible air, water, gas and liquid duties.
Provide the upstream pressure to be maintained and the outlet conditions. Verify the selected pressure range and construction.
PS47 · Pilot-Operated Pressure Sustaining Valve
Pilot-operated regulator that senses upstream pressure for compatible steam and gas services.
Specify the upstream pressure to be maintained, flow range and downstream conditions. A pressure sustaining regulator is not a substitute for a separately required safety valve.
APPLICATION BEFORE SPECIFICATION
Selection Starts with Your Application
Specify the fluid, inlet and required outlet pressures, minimum and maximum flow, operating temperature and connections. Model and size selection depends on the full operating range and the relevant technical specification.
Catalogue & Technical Documents
Review the model-specific technical information and installation requirements. Send a specification, drawing or existing model reference if you need help selecting equipment.
Discuss Your Application
Send your requirements or a photo of the existing equipment for technical assistance and a quotation.
Availability and lead time are confirmed for the requested model and quantity.





