Manual valve in use need to pay attention to the problem

Manual valve is the control component in the pipeline fluid transportation system. It is used to change the passage section and the flow direction of the medium, and has the functions of diversion, cut-off, regulation, throttling, check, diversion or overflow pressure relief. Valves for fluid control, with nominal diameters ranging from extremely small instrument valves to valves for industrial pipelines up to 10m in diameter.

1. manual valve opening and closing:

1. The 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 spindler to move the plate. Some people are accustomed to using spindles, and they should be strictly careful not to use too much force, otherwise it is easy to damage the sealing surface, or the board breaks the handwheel and handle.

2, open and close the valve, force should be stable, not impact. Some of the impact of the opening and closing of the various components of the high-pressure valve has been considered this impact and the general valve can not wait for the Gang.

3, for the steam valve, before opening, should be pre-heated, and exclude condensate, open, should be as slowly as possible, so as to avoid water hammer phenomenon.

4. When the valve is fully opened, the handwheel should be reversed a little to tighten the threads to avoid loosening and damage. For open stem valves, remember the valve stem position when fully open and fully closed to avoid hitting the top dead center when fully open. And it is convenient to check whether it is normal when fully closed. If the valve does fall off, or the valve core seal between the embedded large debris, fully closed when the valve stem position will change.

5. When the pipeline is initially used, there are many internal dirt. The valve can be slightly opened, and the high-speed flow of the medium can be used to wash it away, and then it can be gently closed (not quickly or violently to prevent residual impurities from injuring the sealing surface), open it again, repeat this many times, flush out the dirt, and then put it into normal work.

6. Normally open the valve, there may be dirt on the sealing surface, and it should be washed clean with the above method when closing, and then officially closed.

7. If the handwheel and handle are damaged or lost, they should be equipped immediately and cannot be replaced by the active wrench, so as not to damage the valve stem and fail to open and close, resulting in accidents in production.

8, some media, in the manual valve closed after cooling, so that the valve contraction, the operator should be closed again at an appropriate time, so that the sealing surface does not leave a slit, otherwise, the medium from the slit high-speed flow, it is easy to erode the sealing surface.

9. When operating, if it is found that the operation is too laborious, the reason should be analyzed. If the packing is too tight, can be properly relaxed, such as valve stem skew, should notify the personnel to repair. Some valves, in the closed state, the closing piece is heated and expanded, causing difficulty in opening; if it must be opened at this time, the valve cover thread can be loosened by half a circle to a circle to eliminate the stress of the valve stem, and then the plate moves the handwheel.

2. notes:

1. High-temperature valves above 200°C are at room temperature during installation, and after normal use, the temperature rises, the bolts are heated and expanded, and the gap is increased, so they must be tightened again, called "hot tightening", and the operator should pay attention to this Work, otherwise it is prone to leakage.

2. When the weather is cold, the water valve is closed for a long time, and the water behind the valve should be drained. Condensed water shall also be drained after the steam valve is stopped. The bottom of the valve is like a plug, which can be opened for drainage.

3, non-metallic valves, some hard and brittle, some low strength, operation, opening and closing force can not be too large, especially can not make strong. Attention should also be paid to avoid bumping objects.

4. When using the new manual valve, the packing should not be pressed too tightly, so as not to leak, so as to avoid too much pressure on the valve stem, accelerate the wear and tear, and make it difficult to open and close.