What is Pressure Reducing Valve?

Pressure Reducing Valve

A pressure reducing valve reduces excess pressure in a system by operating on its own. A pressure-reducing valve is also called a pressure-reducer. A pressure-reducing valve’s primary function is to reduce higher pressure to lower. The most common uses of these are in the oil and gas and water industries. Pressure Reducing Valve can be described as an automatic control valve that reduces a higher unregulated inlet pressure to a constant, reduced outlet pressure regardless of changes in the upstream water pressure. 

Types of Pressure Reducing Valves

There are three types of pressure-reducing valves.


Direct-acting PRVs consist of either a flat diaphragm or a convoluted bellows. There is no need for an external sensing line downstream since the system is self-contained. Designed for low to moderate flow, it is the smallest and most economical of the three types. Typically, direct-acting PRVs have an accuracy of +/- 10% of the downstream set point.

Internally piloted piston-operated. 

This type of PRV’s pilot and main valves are integrated into one unit. Pilot valves operate like direct-acting valves. A piston opens the main valve when the pilot valve discharges. By using inlet pressure, this design opens a large main valve that could otherwise be opened directly. Therefore, there is a greater capacity per line size and greater accuracy (+/- 5%) than with direct-acting valves. The internal pressure is also sensed by direct-acting valves, so no external sensor is needed.

Externally piloted

The piston operator of this type replaces the piston operator of the internally piloted design. A greater capacity per line size is possible than with an internally piloted valve thanks to an expanded diaphragm area. The diaphragms are also more sensitive to pressure changes, resulting in an accuracy of +/- 1%. The sensor line is located outside of the valve, where there is less turbulence, which results in improved accuracy. This valve also makes it possible to employ several types of pilot valves (e.g., pressure, temperature, air-loaded, solenoids, or combinations).

Applications of Pressure Reducing Valves

The following services use self-acting pressure reducing valves:

Air and gas services: Direct-acting and pilot-operated pressure reducing valves for air and gas services are used in compressed air systems, power tools, pneumatic control systems, as well as control valves for industrial gas storage systems as well. 

Water services: Pressure-reducing valves are widely used in domestic and industrial water distribution systems and fire protection systems. These services are usually handled by direct-acting pressure-reducing valves. When system pressures become high, it becomes more challenging to maintain them. A pressure reducing valve is used in those lines which can effectively control the pressure downstream to an acceptable limit.

Steam services: The majority of steam applications involving pressure-reducing valves involve direct steam supply, steam engines, and turbines.

Other Services: These valves are used in the following applications:

  • Lubrication systems on heavy industrial equipment and in rolling mills.
  • Pressure control in hydraulic presses.
  • The control of fuel and oil pressure.
  • Reduces pressure in sterilizers, humidifiers, unit heaters, and small process equipment

Advantages of Pressure Reducing Valves

Pressure reducing valves have the following main advantages:

  • Do not require external power.
  • Do not require separate measurement elements or feedback controllers.
  • Low-cost, simple design.
  • High reliability, easy maintenance.
  • The absence of stem packing eliminates external leakage and high friction.
  • Quick response

Functions of Pressure Reducing Valves

A pressure reducing valve (PRV) is a type of valve that reduces the pressure of a fluid or gas to the desired level. The pressure reducing valve achieves this by regulating the flow of fluid through the valve. There are a variety of applications for PRVs, including:

  • Regulating the pressure in a water supply system
  • Maintaining the pressure in a boiler
  • Reducing the pressure of air or other gases in an industrial process

PRVs have several important functions, which include:

  • Preventing over-pressurization: A pressure reducing valve prevents excessive pressure build-up in a system by relieving excess pressure. This protects both the system and its components from damage due to high pressures.
  • Maintaining constant pressure: A PRV can be used to maintain constant pressure in a system by regulating the flow of fluid through the valve. This is especially important in systems where fluctuations in pressure could cause problems, such as in boiler systems.
  • Improving system efficiency: By maintaining constant pressure in a system, a PRV can improve system efficiency by eliminating the need for pumps or other devices to compensate for fluctuations in pressure.
  • The self-contained operation of a pressure-reducing valve allows it to control pressure without any external power source. Its main functions include:
  • A pressure-reducing valve is used to control downstream pressure in steam systems. During pressure fluctuations, this valve automatically adjusts the valve opening and adjusts the pressure.
  • Under certain conditions, pressure-reducing valves can be used to prevent water hammers.
  • In the event of a power outage, they can also be used as bypass valves.
  • By immediately adjusting the downstream pressure, pressure-reducing valves can achieve rapid action.

Aira Euro Automation is a well known Industrial Pressure Reducing Valve Manufacturer and Supplier in India, Since 1990.

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By Admin