PN40 DN25 Spring Type Fire Protection Safety Pressure Relief Valve

Adjustment of opening pressure:

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

② Before installing the safety 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 safety valve meets the requirements.

③ Within the range of the spring working pressure level indicated on the nameplate, you can adjust the opening pressure by rotating the adjustment screw to change the spring compression.

④ Before rotating the adjusting screw, reduce the valve inlet pressure to less than 90% of the opening pressure to prevent the valve flap from being rotated when the adjusting screw is rotated, which may damage the sealing surface.

⑤ In order to ensure that the opening pressure value is accurate, the media conditions, such as media type and temperature, should be as close to the actual operating conditions as possible during adjustment. The type of medium changes, especially when the medium accumulation state is different (for example, from liquid phase to gas phase), and the opening pressure often changes. When the operating temperature increases, the opening pressure generally decreases. Therefore, when 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. How high is related to valve structure and material selection should be based on the manufacturer's instructions.

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