Causes of valve failure

One of the faults is valve failure. The reasons are:

The control channel is blocked by debris (the channel is small, easy to block);

Piston because of rust stuck in the highest position; Although the upper force, but can not move down, open the main channel.

Therefore, the piston valve must be installed before the filter; For new installation or long - term out - of - service pressure relief valves, be sure to disassemble inspection and cleaning.

Fault two, valve straight, no decompression effect. The reasons are:

The piston is stuck in a certain position (not the highest position);

(2) the main valve handle in the cylinder disk guide hole in a position (not close position) stuck;

The main valve disc lower spring break or failure;

Pulse valve handle in the seat hole in a position (not close position) stuck, so that the piston is always under pressure;

(5) between the sealing surface of the main disc and the main seat, there is dirt stuck or Nick;

The diaphragm failed due to fatigue or damage.

For relief valves, special emphasis should be placed on regular inspection. If found dirt, rust should be promptly removed; Piston ring damage should be renewed; Spring failure is replaced by availability; If the sealing surface is not closed, it should be reground; Diaphragm does not work to replace; After use, if confirmed that the valve handle is thick, use sandpaper polishing.

The pressure can not be adjusted after failure of three valves. In addition to the above reasons, there are:

(1) regulating spring failure; (2) cap joint leakage, can not maintain pressure.

This also depends on timely inspection and treatment to prevent.

In addition, there is a phenomenon that the pressure pulse after the valve fluctuations, very unstable. This is the input medium and output medium difference is too large, should re - select the valve with the same diameter. There is also a reason for the pressure after the valve instability is that the adjustment spring is chosen improperly; A nominal pressure reducing valve, adjust the spring there are a few, such as the nominal pressure of 16 kg/cm2, adjusting spring there is 1-3 kg/cm2, 2-8 kg/cm2, 7-11 kg/cm2 three, if after the valve pressure just 1-3 kg/cm2, and spring is 7 to 11 kg/cm2, no the valve pressure is adjustable.