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When the manual valve is operated by the handle on the valve, it is the most common kind of valve on the equipment pipeline. His handle rotates clockwise to close and counterclockwise to open. However, there are some individual valve switches that are exactly the opposite. So when operating, we must pay attention to the sign of opening and closing. In order to avoid unnecessary trouble.
The handle on the valve is designed according to the normal manpower, so the use regulations do not allow the operator to open and close the valve by lever. If the diameter of the handwheel is below 320mm, then the value allows one person to operate, and if it is more than 320mm, two people should operate it. Diaphragm valve and pinch valve, non-metallic valve is strictly prohibited to use the lever operation, nor too hard to close the valve.
Valves such as gate valves and globe valves, which are closed or opened to the limit effective stroke, must return one half or one revolution, so that the threads can be better combined, which facilitates inspection during operation, so as not to tighten the valve too much and damage the valve.
Larger diameter butterfly valves, gate valves and globe valves, and some without bypass valves, its role is to preheat the pipeline and balance the pressure difference between inlet and outlet, reducing opening force. When the valve is opened, the bypass valve should be opened first. After the pressure difference between the two sides of the valve is reduced, the large valve is opened. When closing the valve, close the bypass valve first, then close the large valve.
When the steam medium valve is started, the pipeline must be preheated to remove condensate. When the valve is closed, it must be performed slowly to avoid water hammer and damage to the valve and equipment.
For brake valves and throttle valves with brakes, check the fully-opened or fully-closed indication positions. This can avoid hitting the dead point when fully open. When the valve is closed, it can be found by means of scales and markings that the closing member is detached or against the foreign object and should be eliminated in order to eliminate the malfunction.
When the ball valve, butterfly valve and plug valve are opened, when the groove on the top surface of the valve stem is parallel to the channel, the surface valve is in the fully open position. When the valve stem rotates 90 degrees to the left or right, the groove is perpendicular to the channel and does not love you. The valve is in the fully closed position. Some ball valves, butterfly valves, and whirlwinds are opened parallel to the spanner and the channel, vertical is closed, and reversing marks are performed.
When the valve is operated, the throttle valve and the stop valve can not be used in the throttle valve, so that the sealing surface is easily eroded and the valve is damaged prematurely.
Newly installed pipelines, equipment and valves, which contain many debris such as slag and welding slag, are easily stuck on the sealing surface of normally open valves. They should use a micro-closed method to allow high-speed media to remove these debris, and then light Light off. After several such slight opening and closing, you can wash away.
When some valves are closed, the temperature drops, and the valve parts shrink, creating small gaps in the sealing surface and leaks. Therefore, after the valve is closed, the valve should be closed again when appropriate.
Manual valve operation requirements
About Manual Valve Operation Instructions After the manual valve is installed, the operator must be familiar with the structure and performance of the valve switch, and can clearly distinguish which side is open and which side is off. The correct operation of the manual valve directly affects the service life of the valve and the installation and production of the device.