Time：2021/9/15 23:25:23 Category：TECHNICAL ARTICLE Source： Click：
What are the requirements for safety valve opening pressure adjustment?
Adjustment of the opening pressure of the safety valve:
① Before leaving the factory, the opening pressure of the safety valve should be adjusted one by one to the set value required by the user. If the user proposes the working pressure level of the spring, the lower limit of the pressure level should generally be adjusted before leaving the factory.
② Before installing the safety valve to the protected equipment or before installation, the user must re-adjust at the installation site to ensure that the set pressure value of the safety valve meets the requirements.
③The opening pressure can be adjusted by changing the compression amount of the spring by rotating the adjusting screw within the range of the working pressure level of the spring indicated on the nameplate.
④Before rotating the adjustment screw, the valve inlet pressure should be reduced to below 90% of the opening pressure to prevent the valve disc from being driven to rotate when the adjustment screw is rotated, which may damage the sealing surface.
⑤In order to ensure the accuracy of the opening pressure value, the medium conditions during adjustment, such as medium type and temperature, should be as close as possible to the actual operating conditions. The type of medium changes, especially when the accumulation state of the medium is different (for example, from a liquid phase to a gas phase), the opening pressure often changes. When the working temperature increases, the opening pressure generally decreases. Therefore, when adjusting at room temperature for high temperature, the set pressure value at room temperature should be slightly higher than the required opening pressure value. How high it is is related to the valve structure and material selection, and should be based on the manufacturer's instructions.
⑥Conventional safety valves are used to fix additional back pressure. When the opening pressure is adjusted after inspection (the back pressure is atmospheric pressure at this time), its setting value should be the required opening pressure value minus the additional back pressure value.
Knowledge contributor: Shanghai Wuyue Safety Valve