Basic requirements of safety valve
The safety valve must meet the two requirements of safety and economy in operation. It must be operated with sensitive opening, sufficient discharge, timely return seat and reliable sealing.
Basic technical requirements for safety valves:
1) setting pressure is greater than 3.0 Mpa steam safety valve or medium temperature greater than 235 ° C with safety valve, air or other gas should be able to prevent discharge medium erosion spring directly.
2) the steam safety valve must be equipped with a wrench. When the medium pressure reaches over 75% of the setting pressure, the valve disc can be lifted with a wrench. The wrench should not hinder the valve operation.
3) for toxic or inflammable media, the safety valve must adopt a closed safety valve and prevent the leakage of the cover and cover gasket.
4) in order to prevent the mechanism of adjusting the spring compression amount from loosening, and to change the adjusted pressure at will, the anti-loosening device and lead seal must be installed.
5) the seat shall be fixed to the valve body and shall not be loosened. The fully opened safety valve shall be provided with a mechanism limiting the opening height.
6) the safety valve should be able to reach the rated displacement even if it is partially damaged. When the spring is damaged, the valve disc and other parts will not fly out of the valve body.
7) for the safety valve with additional back pressure, the back pressure balance mechanism shall be set according to the size and variation of its pressure.
8) the pilot relief valve shall be tested for sealing and opening actions of the guide valve and the main valve respectively, which shall meet the performance requirements specified in the standard.