性欧洲精品videos_日本五级床片午夜视频_91精品国产91欠久久码_在线亚洲一区二区欧美色妞影院_五月婷婷第四色激情五月天_女人被添荫蒂洗澡视频_女人流白浆和喷水哪种是高潮_亚洲剧情电影片在线观看_国产欧美性爱另类精品_国产制服丝袜香蕉视频

1. The handwheel and handle of manual valve are designed according to the hand force of ordinary people, considering the strength of sealing surface and necessary closing force.So you can't use a long lever or a long wrench.Do not force too much, too hard, or easy to damage the sealing surface, or break the hand wheel, handle.

2. Open and close the valve to force stable, not impact;

3. After the valve is fully open, the handwheel should be reversed a little to make the threads tight, so as to avoid looseness and damage;

4. For the stem valve, remember the position of the stem when it is fully open and fully closed, avoid hitting the dead point when it is fully open, and facilitate checking whether it is normal when it is fully closed, so as to find whether there is debris embedded in the sealing surface;

5. When the pipeline is initially opened, there are many internal dirty things, so the valve can be slightly opened, and the high speed flow of the fluid can be used to wash it away, and then gently closed (no quick closing or fierce closing to prevent debris damage to the sealing surface), then opened again, and repeated many times, rinse the debris, and then put it into normal operation;

6. If the handwheel and handle are damaged or lost, they should be completed in time. No adjustable wrench should be used instead to avoid damage to the valve stem square and failure to open and close;

7. During the operation, if any labor is found, the reasons should be analyzed.If the packing is too tight, can be properly relaxed, such as the valve stem askew, should be repaired.