1. Before installation, the safety valve should carry out pressure test and air tightness test to check the strength and sealing performance of the safety valve.
Correction and adjustment can only be carried out after it is qualified.
2. On the gas test-bed, the opening pressure of the safety valve is corrected by adjusting the load applied on the disc.
The lever type safety valve adjusts the heavy hammer position, and the spring type safety valve adjusts the spring compression.
The opening pressure of the safety valve shall comply with the relevant provisions of the safety technical supervision regulations for boilers and pressure vessels.
3. On the container, adjust the discharge pressure and return pressure of the safety valve by adjusting the gap between the safety valve regulating ring and the valve disc.
If the safety valve only leaks but does not take off under the opening pressure or takes off but there is a violent vibration and "buzzing" sound after the pressure drop, then the gap is too large and should be adjusted smaller.
If the return pressure is too low, the clearance of the adjusting ring is too small and should be appropriately increased.
The discharge pressure of the safety valve for steam should be less than or equal to 1.03 times of the opening pressure, and the difference between the opening and closing pressure should not be greater than 10% of the opening pressure.
The discharge pressure of the safety valve for air or other gases shall be less than or equal to 1.10 times the opening pressure, and the difference between the opening and closing pressure shall not be greater than 15% of the opening pressure.
4. When the safety valve carries out calibration and pressure adjustment, there must be technical personnel in charge of the safety of the boiler and pressure vessel. The accuracy of the pressure gauge for adjusting and calibrating the device should not be less than level 1. When online adjustment, there should be safety protection measures.
5. In the process of verification, the verifier shall make a record in time.
For qualified safety valves, lead seals should be carried out after the relevant accessory devices are installed to prevent random changes in the adjusted state.
