How to Operate Different Kinds of Valves?

Valves are used in fluid systems to control the direction, pressure, and flow rate of fluids. They are devices that control the flow or stop of the medium in piping and equipment. They are important control components in fluid delivery systems.

Preparation before Operation

Read the operating instructions carefully before operating the valve. Be sure to know the flow of gas before operation. Pay attention to check the valve opening and closing signs. Check the appearance of the valve to see if the valve is wet. If it is wet, dry it. If other problems are found, they must be handled in time. If the electric valve is deactivated for more than 3 months, check the clutch before starting, confirm that the handle is in the manual position, and then check the insulation, steering and electrical wiring of the motor.

Correct Operation Method of Manual Valve

Manual valve is the most widely used valve. Its handle is designed according to ordinary manpower, taking into account the strength of the sealing surface and the necessary closing force. Therefore, you cannot use a long lever or a long wrench to move. Some people are accustomed to using wrenches, who should pay attention to the fact that when opening the valve, the force should be stable, to avoid excessive force. The force should be stable. Some components of high-pressure valves that have been opened and closed by shock have already taken this impact into consideration, and are not equivalent to ordinary valves.

When the valve is fully open, the handwheel should be turned upside down a little to tighten the threads tightly to avoid loosening. For valves with stem, remember the position of the stem when fully open and fully closed to avoid hitting the top dead center when fully open. If the valve is detached, or if large debris is inserted between the valve core seals, the valve stem position will change when fully closed, which will cause damage to valve sealing surface or valve handwheel.

When the groove on the top surface of the ball valve, butterfly valve, and plug valve stem is parallel to the channel, it indicates that the valve is in the fully open position. When the valve stem is rotated 90 ° to the left or right, the groove is perpendicular to the channel, indicating that the valve is in the fully closed position. Some ball valves, butterfly valves, and plug valves are opened with the wrench parallel to the channel and closed with the vertical. The operation of three-way and four-way valves should be performed according to the marks of opening, closing and reversing. After the operation is completed, the movable handle should be removed.

Correct Operation Method of Safety Valve

The safety valve has undergone pressure test before installation. When the safety valve runs for a long time, the operator should pay attention to check the safety valve. During the inspection, people should avoid the safety valve outlet, check the seal of the safety valve, lift the safety valve with a wrench by hand, and open it at intervals, drain the dirt and verify the flexibility of the safety valve.

Traps are valves that are easily blocked by debris such as water pollution. 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 flushing. For a trap without a flushing pipe and a bypass pipe, you can remove the trap, open the shut-off flush, 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 the flushing valve should be opened to clean the pipeline dirt. After the pipeline is flushed, close the bypass valve and the flushing valve, and then activate the pressure reducing valve. Some steam pressure reducing valves have traps in front of them. You need to open them first, then slightly open the shut-off valve behind the pressure reducing valve, and finally open the shut-off valve in front of the pressure reducing valve. Adjust the screw to make the pressure behind the valve reach a predetermined value, then slowly open the shut-off valve behind the pressure reducing valve and correct the pressure after the valve until you are satisfied. Fix the adjusting screw and cover the protective cap.

The Correct Operation Method of Check Valve

In order to avoid the excessively high impact force formed at the moment of the check valve closing, the valve must be closed quickly, so as to prevent the formation of a large reverse flow speed, which is the cause of the impact pressure when the valve is suddenly closed. Therefore, the closing speed of the valve should correctly match the decay speed of the downstream medium.

If the speed of the downstream medium varies widely, the minimum flow rate is not sufficient to force the closing member to stop steadily. In this case, the movement of the closing member can be suppressed with a damper within a certain range of its operating stroke. The rapid vibration of the closing member will cause the moving parts of the valve to wear out too quickly, resulting in premature valve failure. If the medium is a pulsating flow, the rapid vibration of the closing member is also caused by extreme medium disturbance. Where this is the case, the check valve should be placed where the medium disturbance is minimal.

After brief introduction of correct operation methods of main valves, I hope you can learn more about it.