Operating instructions for manual valves

Operating instructions for manual valves

After the manual valve is installed, the operator should 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 equipment.

When the manual valve is operated by the handle on the valve, it is a common valve on the equipment pipe. His handle rotates clockwise to close and counterclockwise to open. However, there are some individual valve switches that are exactly the opposite. Therefore, we must pay attention to the opening and closing signs when operating. So as not to cause unnecessary trouble.

The handle on the valve is designed according to normal manpower, so the use regulations do not allow the operator to open and close the valve with the aid of a lever. If the diameter of the hand wheel is below 320 mm, the value allows one person to operate, and if it is more than 320 mm, two people must operate. Diaphragm valves and pinch valves, non-metallic valves are strictly prohibited to use the lever, and can not be too close to close the valve.

Valves such as gate valves and globe valves are closed or opened to the limit. The effective stroke is to be returned half or one turn to make the threads better combined, which is beneficial for inspection during operation, so as to avoid too tight tightening and damage to the valve.

Larger diameter butterfly valves, gate valves and globe valves, and some without bypass valves, function to preheat the pipeline and balance the inlet and outlet pressure differentials to reduce the opening force. When opening, the bypass valve should be opened first, and then the large valve should be opened after the pressure difference between the two sides of the valve is reduced. When closing the valve, first close the bypass valve and then close the large valve.

To open the valve of the steam medium, the pipe must be preheated to remove the condensed water. When closing the valve, it should be carried out slowly to avoid water hammer and damage the valve and equipment.

For gate valves and throttle valves with brakes, the indicated position of full open or fully closed should be checked. This can avoid the top dead point when fully open. When the valve is closed, the ruler and the mark can be used to find that the closing piece is detached or against the foreign object and should be eliminated to eliminate the malfunction.

When opening the ball valve, butterfly valve or plug valve, 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 is rotated 90 degrees to the left or right, the groove is perpendicular to the channel, and you are not in love with you. The valve is in the fully closed position. Some ball valves, butterfly valves, and whirlwinds are opened with the wrench parallel to the passage, and the vertical is closed, and the reversing mark is performed.

When the valve is operated, the throttle valve and the throttle valve in the shut-off valve cannot be used, which is easy to erode the sealing surface and cause the valve to be damaged prematurely.

Newly installed pipes, equipment and valves, and there are many debris such as dirt and welding slag. The sealing surface of the normally open valve is also easy to stick to the shackles. They should use the micro-closed method to allow the high-speed medium to wash away these debris and lighten Light off. After a few times, the micro-opening can be washed clean.

When some valves are closed, the temperature drops and the valve member contracts, causing small gaps in the sealing surface and leakage. Therefore, the valve should be closed at the appropriate time after closing the valve.

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