The Operation of Safety Valve

Safety valves belong to the category of automatic valves, which are mainly used on boilers, pressure vessels and pipelines. The control pressure does not exceed the specified value, which plays an important role in protecting personal safety and equipment operation. Safety valves must be pressure tested before they can be used. Do you know the specific operation method of the safety valve? 

Adjustment of safety valve 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 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. To ensure that the opening pressure value is accurate, the media conditions, such as media type and temperature, it should be as close to the actual operating conditions as possible during adjustment.

Adjustment of safety valve discharge and seat pressure

1. To adjust the discharge pressure and return pressure of the safety valve, it is necessary to perform an action test of the valve to the full opening height. Therefore, it can only be performed on a large-capacity test device or after the safety valve is installed on the protected equipment. The adjustment method varies according to the valve structure. 

2. For the structure with recoil disk and valve seat adjusting ring, the valve seat adjusting ring is used for adjustment. Unscrew the adjusting ring fixing screw, and extend a tool such as a thin iron rod from the exposed screw hole, then you can turn the gear teeth to make the adjusting ring turn left and right. For the sake of safety, the inlet pressure of the safety valve should be appropriately reduced before turning the adjusting ring, which should generally be lower than 90% of the opening pressure. 

Seal of safety valve

After the safety valve is adjusted, it should be sealed to prevent the adjusted condition from being changed casually. When repairing the safety valve, record the position of the adjusting screw and adjusting ring before disassembling the valve, so as to facilitate the adjustment work after the repair. After readjustment, it should be sealed again.

Do you have any problems with the safety valve operation? Welcome to ask our professional valve experts, we are happy to provide you with various valves and solve valve problems.