Why do pneumatic valves leak? What are the reasons
What happens if the pneumatic valve leaks inside? How to check the pneumatic valve? Internal leakage is a serious threat to the normal operation of the device, and it is difficult to find whether there is internal leakage in the running valve. The investigation results show that the valves used in petrochemical enterprises have different degrees of internal leakage.
Reasons include valve plate, valve seat sealing surface material does not meet the requirements of use, machining accuracy is insufficient, gate valve plate, valve seat wedge Angle mismatch, sealing surface width is different, poor consistency, closing and other factors.
For example, for Z41Y-25, sealing surface material code Y should refer to sealing surface material with relatively soft sealing surface material, corresponding to another sealing surface material is obviously carbide, in fact, some valves only weld carbide on one sealing surface, the other sealing surface is carbon steel body material, due to wear leakage phenomenon.
Another example is the selection of a pipework butterfly valve, seat sealing material using PTFE. From the operating conditions, the requirements are not high, normal temperature and pressure. However, in the process of trial operation, it is found that many valves are not tightly closed, the internal leakage is serious, can not be used normally, need to replace the gate valve. Removal inspection revealed that the valve plate and seat in the closed state has a large clearance, and will be transparent.
The reasons may be as follows: the structure design of pneumatic valve sealing pair is unreasonable or the manufacturing and assembly accuracy does not meet the requirements; Valve installation is not in accordance with the requirements of construction, force is too large; During the construction process, welding slag, sand, metal debris and other impurities into the valve chamber, affecting the sealing effect. In fact, it is more practical, but also the root cause is in the manufacturing, transportation or installation of a certain process do not comply with the standard requirements.
