What are the correct operation methods of several common valves

Correct operation method of safety valve

The safety valve has undergone pressure test and constant pressure before installation. When the safety valve is running for a long time, the operator should pay attention to checking the safety valve. During the inspection, people should avoid the exit of the safety valve, check the lead seal of the safety valve, pull up the safety valve with a wrench by hand, and open it once at intervals. Drain the dirt and verify the flexibility of the safety valve.

Correct operation method of trap

A trap is a valve that is easily blocked by debris such as water and dirt. When enabled, first open the flush valve and flush the pipeline. If there is a bypass pipe, the bypass valve can be opened for short-term flushing. For traps without flushing pipes and bypass pipes, remove the traps, open the shut-off flushing, and then close the shut-off valve, install the trap, and then open the shut-off valve to activate the trap.

Correct operation method of pressure reducing valve

Before the pressure reducing valve is activated, the bypass valve or flushing valve should be opened to clean the pipeline dirt. After the pipeline is flushed, the bypass valve and the flushing valve should be closed, and then the pressure reducing valve should be activated. Some steam pressure reducing valves have traps before they need to be opened first, then slightly open the shut-off valve after the pressure reducing valve, and finally open the shut-off valve before the pressure reducing valve, watch the pressure gauges before and after the pressure reducing valve, and adjust the pressure reducing valve Adjust the screw to make the pressure after the valve reach a predetermined value, then slowly open the shut-off valve after the pressure reducing valve, and correct the pressure after the valve until you are satisfied. Fix the adjusting screw and cover the protective cap.

If the pressure reducing valve fails or needs to be repaired, first slowly open the bypass valve and close the shut-off valve before the valve. Manually adjust the bypass valve so that the pressure after the pressure reducing valve is basically stable at the predetermined value before closing. After the pressure reducing valve is replaced or repaired, it returns to normal.

Correct operation method of check valve

In order to avoid the excessively high impact force at the moment of closing of the check valve, the valve must be closed quickly to prevent the formation of a great reverse flow velocity, which is the cause of the impact pressure when the valve is suddenly closed. Therefore, the closing speed of the valve should be correctly matched with the attenuation speed of the downstream medium.

If the velocity of the downstream medium varies widely, the minimum flow velocity is not enough to force the closure to stop stably. In this case, the movement of the closing member can be suppressed by a damper within a certain range of its movement stroke. The rapid vibration of the closing parts will cause the valve moving parts to wear too quickly, leading to premature failure of the valve. If the medium is a pulsating flow, the rapid vibration of the closing member is also caused by extreme medium disturbance. Whenever this situation exists, the check valve should be placed where the medium disturbance is minimal.