Precautions for operating stop valves

For stop valves, you not only need to be able to install and maintain them, but you also need to be able to operate them.
To open and close the stop valve, the force should be steady and not impacted. Some components of high-pressure stop valves that impact opening and closing have considered that this impact force cannot be the same as that of general stop valves.
When the stop valve is fully open, the handwheel should be turned slightly to make the threads tight to avoid loosening and damage.
When the pipeline is first used, there is a lot of dirt inside. You can slightly open the stop valve, use the high-speed flow of the medium to wash away the dirt, and then close it gently (do not close quickly or slam it to prevent residual impurities from pinching the sealing surface) , turn it on again, repeat this many times, rinse away the dirt, and then resume normal work.
For normally open stop valves, there may be dirt stuck on the sealing surface. When closing, use the above method to flush it clean, and then officially close it tightly.
If the handwheel or handle is damaged or lost, it should be replaced immediately. Do not use a swing wrench to replace it, so as to avoid damage to the four sides of the valve stem, failure to open and close properly, and even an accident in production.
Some media will cool down after the stop valve is closed, causing the valve to shrink. The operator should close it again at an appropriate time to leave no slits on the sealing surface. Otherwise, the medium will flow through the slits at high speed and easily erode the seal. noodle.
During operation, if you find that the operation is too strenuous, you should analyze the reasons. If the packing is too tight, loosen it appropriately. If the valve stem is skewed, notify personnel to repair it. When some stop valves are in the closed state, the closing parts are heated and expand, making it difficult to open. If it must be opened at this time, the valve cover thread can be loosened by half a turn to one turn to eliminate the stress on the valve stem, and then turn the hand wheel.