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Manual low temperature valve is operated by hand wheel and handle. It is widely used in petrochemical plant. Operators should pay attention to the following points:

1. The opening direction of the low temperature valve is usually counterclockwise indicating that the valve is open and clockwise indicating that the valve is closed. Therefore, pay attention to the direction when opening and closing the valve.

2. The handle of low temperature valve and the size of hand wheel are designed according to the manual switch of valve. Therefore, the valve can be turned on and off by hand. Levers or wrenches are generally not allowed to be used to turn the valve on and off. In order to prevent excessive force, damage sealing surface and other parts.

3. When the closed type open gate valve and globe valve to the dead point, to turn 1/4 turn to 1/2 turn, make the thread better close, so as not to screw too tight, damage valve parts.

4. The gate valve and globe valve can not be throttled, so it is easy to wash the valve plate and sealing surface, and the introduction of vibration leakage, damage the valve.

5. When opening the steam valve, it should be opened slowly to eliminate the condensed water in the pipeline and prevent the phenomenon of water blow. Damage valves and pipes.

6. Large diameter gate valve, globe valve and butterfly valve, some are equipped with bypass valve, its function is to balance the pressure on both sides of the valve, reduce the opening force. Therefore, when opening, the bypass valve should be opened first, and then slowly open the valve. When closing the valve, the bypass valve should be closed first, and then slowly close the main valve.

7. After some low-temperature valves are closed, when the temperature drops, the valve parts shrink and the sealing surface appears slight leakage phenomenon. At this time, the valve should be closed and then properly tightened once.