1. Under what circumstances does the safety valve need to be verified?
(1) Long-term storage or before the first use
(2) Regular calibration
(3) Valves with severe damage and corrosion
(4) Valve nameplate lost valve
(5) Valves damaged by seals
2. The significance and method of adjusting the pressure of returning to the seat
The recoil pressure defined by the national standard means that after the safety valve reaches the discharge state, the medium pressure drops to a certain value, and the valve flap is re-contacted with the valve seat, that is, the opening height becomes zero. The static pressure at the valve inlet and the return pressure are too low. Too high is not good, too low will cause loss of medium and energy, too high will not reach the discharge, causing the frequency of the valve to jump, the principle is to increase the return pressure as much as possible, reduce the medium And the loss of energy.
3. Adjustment method
The return pressure is adjusted by adjusting the ring. The principle of adjustment is the principle of the gap. The smaller the gap is, the greater the resistance is when the spray is released. The greater the force that holds the spool, the more difficult it is to return to the seat. Otherwise, the gap is larger. The easier the spool is to fall back, the higher the return pressure.
For the safety valve with only the lower adjustment ring, the adjustment ring is adjusted upwards, the return pressure is lowered, the adjustment ring is adjusted downward, and the return pressure is increased. For the safety valve with the upper and lower adjustment rings, the distance between the upper and lower adjustment rings is reduced, and the return pressure is reduced. Lower, the distance between the upper and lower adjustment rings increases, and the return pressure increases.
