Adjustment of Gate Valve opening pressure

It is a special valve whose opening and closing parts are in a normally closed state under the action of external force. When the medium pressure in the equipment or pipeline rises above the specified value, it discharges the medium outside the system to prevent the medium pressure in the pipeline or equipment from exceeding the specified value. In order to ensure that the Gate Valve can fully play its protective role in pressure vessels and pipelines, users should understand the relevant knowledge of Gate Valve opening pressure adjustment.

① Before the Gate Valve leaves the factory, its opening pressure should be adjusted one by one to the setting value required by the user. If the user proposes a spring working pressure level, the factory adjustment should generally be made according to the lower limit of the pressure level.
② Before installing the Gate Valve on the protected equipment or before installation, the user must readjust it at the installation site to ensure that the set pressure value of the Gate Valve meets the requirements.
③ Within the spring working pressure level range indicated on the nameplate, the opening pressure can be adjusted by changing the spring compression amount by rotating the adjusting screw.
④ Before rotating the adjusting screw, the valve inlet pressure should be reduced to less than 90% of the opening pressure to prevent the valve disc from being driven to rotate when the adjusting screw is rotated, thereby damaging the sealing surface.
⑤ In order to ensure the accuracy of the opening pressure value, the medium conditions during adjustment, such as medium type, temperature, etc., should be as close as possible to the actual operating conditions. When the type of medium changes, especially when the accumulation state of the medium is different, the opening pressure often changes. As the operating temperature increases, the cracking pressure generally decreases. Therefore, when adjusting at normal temperature and using it at high temperature, the set pressure value at normal 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 Gate Valve are used when additional back pressure is fixed. When adjusting the opening pressure after inspection, the setting value should be the required opening pressure value minus the additional back pressure value.