Introduce the cause of leakage after valve closure

1. The causes of leakage are as follows:
The sealing surface is not grinded well.
(2) The seal ring is not tightly matched with the seat and disc;
(3) The connection between disc and stem is not firm.
(4) Stem bending and torsion, so that the upper and lower closures are not in alignment;
(5) Close too fast, the sealing surface is not in good contact or has been damaged;
_Material selection is inappropriate and can not withstand the corrosion of medium;
_Use globe valve and gate valve as control valve. The sealing surface can not withstand the erosion of high-speed flowing media.
_Certain media will gradually cool down after the valve closes, resulting in slits on the sealing surface and erosion.
_Threaded connections are used between some sealing surfaces and seats and discs. Oxygen concentration batteries are prone to corrosion and loosening.
_The valve can not be closed because of the embedding of impurities such as welding slag, rust, dust, or the falling off of mechanical parts in the production system to block the valve core.
2. The precautions are as follows:
Before use, the leak must be tested carefully, and the leak of sealing surface or the root of sealing ring should be handled before use. Second, the parts of the valve should be checked in advance, and the valves with bending and twisting of the stem or the connection between the disc and the stem should not be used.
(3) Valve closure should be stable and not vigorous. If it is found that the contact between sealing surfaces is not good or obstructive, it should be opened slightly immediately to let the miscellaneous flow out, and then carefully closed;
When choosing valves, not only the corrosion resistance of the valve body, but also the corrosion resistance of the closing parts should be considered.
_According to the structural characteristics of the valve, the parts that need to regulate the flow rate should adopt the regulator valve.
For the case of medium cooling and large temperature difference after closing the valve, the valve should be closed after cooling.
When the seat, disc and sealing ring are connected by threads, PTFE tape can be used as filler between threads so that there is no void.

_Valves that may fall into impurities should be filtered in front of the valves.