Precautions when choosing a pressure relief valve

Precautions when choosing a pressure relief valve

Pressure parameters

-Rated pressure: According to the working pressure of the equipment, select a pressure relief valve that is compatible with the rated pressure. Its rated pressure should be higher than the normal working pressure of the equipment, generally 1.2 to 1.5 times the working pressure.

-Opening pressure: It should be determined based on the maximum pressure that the equipment can withstand. The opening pressure should be lower than the equipment's pressure resistance limit to ensure timely protection in case of abnormal pressure.

-Return pressure: The return pressure is generally 75% to 90% of the opening pressure. It is necessary to ensure that the valve can be closed in a timely manner after the pressure is released to avoid excessive discharge of the medium.

Displacement parameters

-Calculate displacement requirement: Based on factors such as the storage capacity of the medium inside the equipment, the possible rate of pressure rise, and the allowable range of pressure rise, calculate the minimum displacement required for the pressure relief valve. The selected valve displacement should be greater than the calculated value.

-Consider operating condition margin: In some special operating conditions, such as high temperature, high pressure, high viscosity media, etc., the emission characteristics of the media may change, and the displacement margin should be appropriately increased.

Medium characteristics

-Physical properties: Considering the state, viscosity, density, etc. of the medium, for media with high viscosity, pressure relief valves with large flow area and low resistance should be selected.

-Chemical properties: If the medium is corrosive, corrosion-resistant materials such as stainless steel, Hastelloy, etc. should be selected for pressure relief valves.

Connection method

-Common connection types: threaded connection, flange connection, welded connection, etc. Small caliber, low-pressure pressure relief valves often use threaded connections; Medium to large and high-pressure pressure relief valves are generally connected by flanges or welding.

-Matching pipeline parameters: The connection size should be consistent with the interface and pipeline size of the equipment, while considering the sealing performance of the connection and the convenience of installation and maintenance.