Methods for eliminating safety valve faults

The main cause of safety valve failure is improper design, manufacturing, selection, or use. If these faults are not eliminated in a timely manner, they will affect the effectiveness and service life of the valve, and even fail to provide safety protection. The common faults and their elimination methods are as follows:

1. Leakage

Under normal operating pressure of the equipment, leakage exceeding the allowable level occurs between the valve disc and the sealing surface of the valve seat. The reason is that there is dirt between the valve disc and the sealing surface of the valve seat. You can use a lifting wrench to open the valve several times and flush away the dirt; Sealing surface damage. According to the degree of damage, repair should be carried out by grinding or grinding after turning; The valve stem is bent, tilted, or the lever and fulcrum are skewed, causing the valve core to be misaligned with the valve disc. Should be reassembled or replaced; The elasticity of the spring decreases or loses its elasticity. Measures such as replacing the spring and readjusting the opening pressure should be taken.

2. Do not open when the specified pressure is reached

The reason for this situation is inaccurate constant pressure, and the compression amount of the spring or the position of the heavy hammer should be readjusted; The valve disc is stuck to the valve seat. Regular manual air release or water discharge tests should be conducted on safety valves; The lever of the lever type safety valve is stuck or the heavy hammer is moved. The position of the heavy hammer should be readjusted and the lever should move freely.

3. Open below the specified pressure

Mainly due to inaccurate constant pressure; The spring has aged and its elasticity has decreased. The adjusting screw should be tightened appropriately or the spring should be replaced.

4. The pressure continues to rise after exhaust

This is mainly because the selected safety valve has a small displacement and the safety discharge capacity of the flat equipment should be re selected with a suitable safety valve; The centerline of the valve stem is not aligned or the spring is rusted, which prevents the valve disc from opening to the desired height. The valve stem should be reassembled or the spring replaced; The exhaust pipe section is insufficient, and an exhaust pipe that meets the safe emission area should be used.

5. Valve disc frequency jump or vibration

Mainly due to the high stiffness of the spring, a spring with appropriate stiffness should be used instead; Improper adjustment of the adjustment ring leads to excessive reseating pressure. The position of the adjustment ring should be readjusted; Excessive resistance in the discharge pipeline results in excessive discharge back pressure. The resistance of the discharge pipeline should be reduced.

6. The valve disc does not return to its seat after discharge

This is mainly caused by the spring bending of the valve stem, improper installation position of the valve disc or being stuck, and should be reassembled.