Opening and closing procedures of manual instrument valve

Opening and closing procedures of manual instrument valve
For the steam instrument valve, it should be heated in advance before opening, and the consolidated water should be removed. When opening, it should only be slow to avoid water hammer.
When the instrument valve is fully opened, the hand wheel should be turned back a little to make the threads tight to avoid loosening and damage.
For the rising stem instrument valve, remember the position of the stem when it is fully open and fully closed, and prevent it from hitting the upper world point when it is fully open. It is convenient to check whether it is normal when it is fully closed. If the valve do scattered, or plug seal embedded between larger debris, fully closed when the stem position will change.
When the pipeline is used for the first time, there is a lot of internal dirt. The high-speed flow of the medium is used to wash it away, and then it is closed quietly (it can't be closed quickly or fiercely to prevent the residual impurities from damaging the sealing surface). It is opened again and again, and the dirt is washed away and put into normal operation again and again.
If the instrument valve is normally opened, there may be dirt on the sealing surface. When it is closed, it should also be washed and cleaned with the above essentials, and then it should be formally closed.
If the hand wheel and handle are damaged or lost, they should be equipped immediately, and can not be replaced by the flexible wrench, so as to avoid damaging the four sides of the valve stem and causing accidents in production.
When operating, if it is found that the operation is too laborious, the reason should be analyzed. If the packing is too tight, it can be grasped properly. If the valve stem is skew, it should be repaired by the staff. When some instrument valves are in the closed state, the closing parts shrink when heated, which makes it difficult to open; If the valve is opened at this time, the thread of the valve cover can be loosened half a turn to one turn to eliminate the stress of the valve stem, and then the handwheel can be moved.
Some media are cooled after the instrument valve is closed to shrink the valve. The operator should close the valve again at the right time, so that there is no slit on the sealing surface. Otherwise, the media will flow through the slit at a high speed, and it is easy to erode the sealing surface.