The Function of a Pressure Regulating Valve, and How It Works

In the world of construction, especially related to piping and mechanical work, we know a tool called PRV.

 (PRV pada sistem turbine / image credit : )

What is PRV?

PRV is a continuation of the pressure control valve, which is a tool (valve) that controls a gas or liquid pressure system from a high pressure source system to generate more pressure low depending on the requirements of a system.

PRV function

High pressure system sources such as compressors, pumps, tanks and other high pressure systems that are distributed to a particular system are first reduced to meet the specifications of the requirements of the system or also for safety and security requirements. This is the main function of installing the pressure control valve (PRV).

An example of using PRV is the water cycle system in tall buildings. A clean water installation system in tall buildings is strongly affected by the gravity of the earth, which leads to an increase in water pressure. The higher the building, the higher the water pressure on the ground floor, and this jeopardizes the installation of the pipes, including damage to the sprinkler and other support devices, if this is the case. A pressure regulator (PRV) is not installed. The presence of a water pressure reducing valve is used to regulate the water pressure so that it is stable and even.

The placement of the water pressure relief valve (PRV) for clean water in multi-story buildings depends on the requirements on site. In general, however, the placement takes place on 6 floors. With a floor height of 3 meters, the pressure reducing valve is placed 18 meters. The maximum water pressure at the PRV inlet is 3 to 4 kg / cm2. This is to maintain the safety of tools that use water, e.g. B. the shower jet with a maximum pressure limit of 4.5 kg / cm2, taps, sinks and other tools. Imagine what happens when the water from the main pump, which exerts a pressure of around 8 to 12 bar, leads directly to the seed drill or the tap?

The use of water in tall buildings is used not only in circulation, but also frequently in the oil and gas industry and in the power generation industry.

Types of pressure control valves


Pressure Regulating Valve (PRV) or also called Pressure Reducing Valve seen from the operational system can be divided into 2 types, namely:

1. PRV one stage

2. Two-stage PRV

A. One-Stage PRV

(Detail PRV 1 Tahap / image

The image above is a GRP system with a single stage pressure regulator. Some of the main components of the GRP appear, namely: inlet and outlet pressure gauge, diaphragm membrane, springs, mushroom valve, as well as levers to regulate the set point of the GRP operating pressure. has the functions and uses of each

  • The pressure gauge is used to designate the fluid pressure values ​​on both the pressure source side and the PRV outlet side.
  • The diaphragm is used to create a flexible workspace in the GRP that is capable of changing the volume.
  • Two springs in the PRV system operate to produce pressure balance, while the Poppet valve operates to open and close the flow of fluid.

How the PRV works in one step

The operating principle of the pressure regulating valve (one stage) generally uses the principles of a mechanical system and there is no electrical system at all.

If the fluid pressure in the outlet area drops (the area is a lighter blue), then what happens is that the part inside the diaphragm shrinks because the spring 1 presses on the diaphragm. In addition to this, the spring 1 will also press the mushroom valve in order to open the flow of fluid to enter the diaphragm area. Fluid can enter this area because it has a pressure higher than the pressure inside the diaphragm area.

Under certain conditions, the pressure of the fluid in the outlet zone coupled with the pressure of the spring 2, will be strong enough to resist the thrust of the spring 1 which is larger than the spring 2. For these conditions to create a balance which causes the valve plug to close.

The process continues, and so on, each press in the downstream PRV is less than the setpoint it should be.

B. Two-stage GRP

(Detail PRV 2 Tahap / image

In contrast to the single-stage PRV, the PRV with two-stage pressure regulator uses more springs and diaphragms to create a compensation chamber in the PRV (chamber). This is the most fundamental difference to a single-stage GRP.

Two-stage PRV operation

When the pressure of the fluid in the outlet chamber decreases, the spring 1 presses on the membrane and the valve valve 1, so that the fluid enters the outlet chamber with higher pressure in the chamber. When the pressure of the fluid in the chamber drops because it has to enter the outlet chamber, the same process occurs in the spring 4 which presses the flap valve 2 so that the fluid enters the chamber with higher pressure from the bedroom. If the outlet fluid pressure corresponds to the set pressure, the spring system compensates so that the two flap valves are closed completely.

Looking at the operation of the two PRVs, one has the impression that both PRV types have the same function, but are used under slightly different conditions. A PRV with a single pressure control stage is better suited for use with liquids with low working pressure. The GRP with a two-stage pressure regulator, on the other hand, is more suitable for working fluids with very high pressure.

Hence a description of what a pressure control valve is and its type and function. If this article is useful, please share it.