Industrial valve is a device used to control the direction, pressure, and flow rate of a fluid in a fluid system. It is a device that allows the medium (liquid, gas, powder) in pipes and equipment to flow or stop, and its flow can be controlled. Valves are important control components in fluid delivery systems.
Pre-operation preparation
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 dampened.If there is moisture, the valve should be dried;
If other problems are found, they must be handled in time, and no fault operation is allowed.If the electric valve is deactivated for more than 3 months, check the clutch before starting.After confirming that the handle is in manual position, check the insulation, steering and electrical wiring of the motor.
The correct operation of the manual valve
Manual valve is the most widely used valve. Its handwheel or 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. They should pay close attention to the fact that when opening the valve, force should be smooth and stable. For some high-pressure valves with impact opening and closing, the components have already considered this kind of impact, which is not equivalent to ordinary valves.
When the valve is fully open, the handwheel should be turned upside down a little to tighten the threads and to avoid loose damage. For rising stem valves, remember the position of the stem when fully open and fully closed .Avoid hitting the top dead center when fully open and easily checking whether it is normal when fully closed.
If the valve disc falls off, or there is large debris inserted between the valve core seals, the stem position will change when the valve is fully closed, and the valve sealing surface or the valve handwheel will be damaged.
Valve opening sign: 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 rod is rotated 90 ° to the left or right, the groove is perpendicular to the channel, indicating the valve is in the fully closed position.
Some fully welded body 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 and constant pressure 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 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.
Correct operation method of trap
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, the trap should be removed. Open the shut-off valve and flush, then close the shut-off valve. Install the trap, 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 or 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 shutoff valve behind the pressure reducing valve, and finally open the shutoff valve before the pressure reducing valve. Watch the front and back pressure gauges of the pressure reducing valve, adjust the screw to make the pressure of the back gauge reach the predetermined value, then slowly open the shut-off valve behind the pressure reducing valve and correct the pressure until proper. Fix the adjusting screw and cover the protective cap.
If the pressure reducing valve fails or needs to be repaired, the bypass valve should be slowly open and close the shut-off valve at the same time. Manually adjust the bypass valve so that the rear pressure is basically stabilized at a predetermined value. After replacement or repair, then return to normal.
The correct operation method of check valve
In order to avoid the excessive impact caused by the check valve closing,
The valve must close quickly to prevent extreme backflow speeds,
This reverse flow speed is the cause of the shock 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.