How to ensure that the ball valve does not leak

- Apr 06, 2019-

How to ensure that the ball valve does not leak



In order to ensure the sealing performance at low working pressure of the medium, a certain pre-tightening specific pressure must be formed between the sphere and the sealing seat. In the rigid seats, the reliability and service life of stainless steel work, and the pre-compression quantity clamped in the seats is correctly selected. In order to ensure the sealability of stainless steel ball valves under low medium working pressure, a certain pre-tightening specific pressure must be formed between the ball and the sealing seat. In rigid seats, the reliability and service life of stainless steel ball valves and the pre-compression quantity clamped in the seats are correctly selected. The insufficient pre-compression can not guarantee the low-pressure sealing of the ball: too much pre-compression will increase the friction moment between the ball and the sealing seat, which will affect the performance of the stainless steel ball valve, and may cause the plastic deformation of the sealing seat, leading to sealing failure. For PTFE seals, the pre-tightening specific pressure should generally be 0.1 PN and not less than 1.02 MPa. The adjustment of the pre-compression of rigid seats is realized by changing the thickness of the sealing adjustment gasket. The processing error of the sealing adjustment gasket will affect the effect of the adjustment. Reasonable assembly and adjustment is the key to obtain good sealing. In use, the automatic regulation ability of the pre-tightening specific pressure is poor after the seal seat is worn, so the service life of the ball valve with rigid seal seat structure is relatively short. One of the ways to solve the problem is to use the sealing seat with elastic elements. At this time, the acquisition and adjustment of pre-compression is realized by elastic elements instead of relying on sealing adjustment gaskets. In addition to obtaining the necessary pre-compression, the sealing seat with elastic elements can also compensate the pre-compression specific pressure within the elastic deformation range of the elastic elements. Therefore, the service life of the ball is relatively long. The key to the sealability of stainless steel ball valves lies in the structure of seats and the selection of seating materials. According to different structure and use requirements, reasonable selection of seal seat structure form to ensure good processing technicality of seal seat: selection of sealant with good performance and adaptability to use requirements, meeting the sealing requirements of ball valves, improving the reliability and service life of ball valves are the key issues to be considered in the improvement design of ball valves.


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