Selecting Guide of Pressure Reducing Valves
Pressure reducing valves (PRVs) are installed in many industrial systems to ensure that the pressure of the outgoing fluid is maintained at a safe, desired and constant level. They are most commonly used on boilers, gas or oil lines, or any other pressurized liquid, gas or steam system. However, this device is not as simple as it appears. Before installation, it is important to select the proper PRV by taking into consideration a variety of factors including the pressure requirements of the system and the type of fluid being used. Here are some guidelines for selecting the right PRV.
First, consider the maximum working pressure of the system. A PRV should be selected to match the system pressure requirements. If the pressure exceeds the PRV’s maximum working pressure, it could be damaged and cause a failure of the system. The chart below can help you determine the maximum working pressure for PRVs.
Next, consider the type of fluid that will be used in the system. High temperature fluids, corrosive fluids, and extremely viscous fluids require special PRVs that can withstand the specific stress they create. Knowing what fluids your system uses will help you determine the type of PRV required.
Third, consider the rate of pressure drop or the pressure difference between inlet and outlet of the system. When the pressure difference is greater than the PRV’s specified range, the PRV must be able to withstand the additional pressure. Replacing oversized valves with more accurately sized valves is one way to reduce pressure drop.
Fourth, consider the type of valve used. There are two main types of pressure reducing valves; direct-acting PRVs and pilot-operated PRVs. The type of valve used will depend on what type of additional control or adjustment is required on the system.
Finally, consider the cost of the PRV. The cost of PRVs may vary greatly depending on the design, quality and size of the valve. It is important to understand that cost should not be a major factor in selecting a PRV.
When selecting a pressure reducing valve, it is important to take all of these factors into consideration. The best way to ensure an accurate selection is to consult a professional. However, following the guidelines discussed above should provide enough information that an informed decision can be made.
