Vacuum valve opening pressure adjustment instructions

Vacuum valve opening pressure adjustment

1 Before the safety valve is delivered from the factory, the opening pressure should be adjusted one by one to the user's required setting value. If the user proposes a spring working pressure level, it should generally be adjusted according to the lower limit of the pressure level.

2 The user must re-adjust the safety valve at the installation site before installing the safety valve on the protected equipment or before installation to ensure that the set pressure value of the safety valve meets the requirements.

3 Within the range of the spring working pressure level 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 flap from being rotated when the adjusting screw is rotated, so that the sealing surface is damaged.

5 In order to ensure that the opening pressure value is accurate, the medium conditions during adjustment, such as the type of medium and temperature, should be as close as possible to the actual operating conditions. The type of medium changes, especially when the medium is in a different accumulation state (for example, from a liquid phase to a gas phase), and the opening pressure often changes. When the operating temperature rises, the opening pressure generally decreases. Therefore, when it is adjusted at normal temperature and used for high temperature, the set pressure value at normal temperature should be slightly higher than the required opening pressure value. The degree to which it is high is related to the valve structure and material selection, and should be based on the manufacturer's instructions.

6 Conventional safety valve is used to fix the additional back pressure. When the opening pressure is adjusted after inspection (the back pressure is atmospheric pressure), the setting value should be the required opening pressure value minus the additional back pressure value.