How to operate the manual valve on site, the correct valve operation method: For the valve, not only will it be installed and maintained, but also will operate.
Manual valve opening and closing:
1. The manual valve is a valve using Zui Guang. Its hand wheel or handle is designed according to ordinary manpower, considering the strength of the sealing surface and the necessary closing force. Therefore, you cannot use long levers or long wrenches to move. Some people are accustomed to using the wrench, should pay strict attention, do not use too much force, otherwise it is easy to damage the sealing surface, or the plate breaks the hand wheel, handle.
2, open and close the valve, the force should be stable, not impact. Some components of high-pressure valves that have been opened and closed by impact have been considered such that the impact force cannot be equal to that of a general valve.
3. For steam valves, pre-heating should be carried out before opening, and condensed water should be removed. When opening, it should be as gentle as possible to avoid water hammer.
4. When the valve is fully open, the handwheel should be reversed a little to make the threads tightly tight to avoid loose damage. For open-end valves, keep in mind the position of the stem when fully open and fully closed to avoid hitting the top dead center when fully open. And it is easy to check whether it is normal when fully closed. If the valve is detached or a large debris is embedded between the valve plug seals, the position of the valve stem will change when fully closed.
5. When the pipeline is used at the beginning, there are many internal dirt, the valve can be slightly opened, the high-speed flow of the medium is used, and the medium is washed away, and then gently closed (can not be closed quickly and violently closed, to prevent residual impurities from pinching the sealing surface) ), turn it on again, repeat this many times, flush the dirt, and put it into normal work.
6. Normally open the valve, there may be dirt on the sealing surface. When it is closed, it should be washed clean by the above method, and then officially closed.
7. If the handwheel or handle is damaged or lost, it should be immediately equipped. It should not be replaced by a live wrench, so as not to damage the valve stem, and the opening and closing is not working, resulting in an accident in production.
8. Some media, after the valve is closed, cool, so that the valve member shrinks, the operator should close it again at the appropriate time, so that the sealing surface does not leave a slit. Otherwise, the medium flows through the slit at high speed, which is easy to erode. Sealing surface.
9. When operating, if the operation is too laborious, analyze the cause. If the packing is too tight, it can be properly relaxed. If the valve stem is skewed, the person should be notified to repair it. In some cases, when the valve is closed, the closing member is heated and expanded, which makes opening difficult; if it must be opened at this time, the bonnet thread can be loosened by half a turn to one turn, the stem stress is eliminated, and then the hand wheel is driven.
On-site valve notes:
1. The high temperature valve above 200 °C is at normal temperature during installation, and after normal use, the temperature rises, the bolt expands and the gap increases, so it must be tightened again, called “heat tight”. The operator should pay attention to this work. Otherwise, it is easy to leak.
2. When the weather is cold, the water valve should be closed for a long time, and the water behind the valve should be removed. After the steam valve is stopped, the condensate should also be excluded. The bottom of the valve is like a wire plug that can be opened to drain.
3, non-metallic valves, some are hard and brittle, and some have low strength. When operating, the opening and closing force should not be too large, especially not to make it strong. Also pay attention to avoiding object bumps.
4. When the new valve is used, the packing should not be pressed too tightly, so as not to leak, so as to avoid the valve stem being pressed too much, speeding up the wear, and it is difficult to open and close.