Common faults and elimination methods for safety valves
Release time：2018-08-29 Browse：449
After the safety valve is installed, it often causes many failures due to improper use. If these faults are not eliminated in time, the function and service life of the safety valve will be affected. Common faults are:
(1)The valve flap does not return to the seat after discharge
This is mainly caused by the spring-bending valve stem, the valve flap is not installed properly, or is stuck. Should be reassembled.
(2)Leak
Under the normal working pressure of the device, more than the allowable leakage between the disc and the seat sealing surface occurs. The reason is that there is dirt between the valve flap and the sealing surface of the valve seat. The valve can be opened several times with a lift wrench to flush the dirt; the sealing surface is damaged. It should be repaired by grinding or grinding after grinding according to the degree of damage; the stem is bent, tilted or the lever and the fulcrum are skewed, so that the valve core and the valve disc are misaligned. Should be reassembled or replaced; the spring elasticity is reduced or loses its elasticity. Measures such as replacing the spring and re-adjusting the opening pressure should be taken.
(3)Do not open when the pressure is specified
The reason for this is that the pressure is not accurate. The amount of compression of the spring or the position of the weight should be readjusted; the disc is stuck to the seat. The safety valve should be manually deflated or drained periodically; the lever of the lever safety valve is stuck or the weight is moved. The weight position should be re-adjusted and the lever moved freely.
(4) Pressure continues to rise after exhaustion
This is mainly because the safety valve displacement of the selected safety valve is small, and the safety valve should be re-selected; the stem line is not correct or the spring Rusting, so that the valve flap can not be opened to the proper height, the valve stem should be reassembled or the spring should be replaced; if the exhaust pipe is not enough, the exhaust pipe should be taken to meet the safe discharge area.
(5) flap frequency jump or vibration
Mainly due to the spring stiffness is too large. Should use the appropriate stiffness of the spring; improper adjustment of the adjustment ring, so that the return pressure is too high. The position of the adjustment ring should be readjusted; the resistance of the discharge pipe is too large, causing excessive discharge back pressure. The discharge pipe resistance should be reduced.
(6)Unable to open pressure
mainly the pressure is not accurate; the spring aging elasticity drops. The adjusting screw or the spring should be properly tightened.
