The first is to increase the sealing grease method; this method is not used to seal the oil body, you can consider increasing the seal oil to improve the performance of the valve stem seal. Daily maintenance of the usual time, increase the supplementary seal oil is also one of the necessary maintenance procedures.
The second is the change in the flow, and placed P2 in the stem end method; when p] larger P1 and large sealing P1 obviously than the seal P2 difficult. Thus, it can be take changes in the flow of method, the P1 stem end changed to P2 in the stem end, the high pressure, pressure of the valve is more effective. Such as bellows valves should be considered on the normally seal P2.
The third is using lens pad seal method; for, under the lid seal, the sealing of the valve seat and the upper and lower body. If it is a plane sealing, under high temperature and high pressure, sealing difference, causing leaks, you can use the lens pad seal, can get satisfactory effect.
The fourth is to increase packing method; usually adopts double-layer or multi-layer hybrid filler form simply increase the sealing gasket number, such as 3 to 5, to improve the valve stem sealing performance, but the effect is not very obvious.
Fifth is to replace graphite packing method; PTFE packing is widely used, and the application of the temperature in the range of 20 to 200 DEG C, when the working temperature limit, lower limit variation is large, the sealing performance will be decreased, and aging fast, short life. Here recommend using flexible graphite packing can overcome difficulties of PTFE packing can not afford, and the service life is long, thereby enhancing the reliability of sealing. There are many factories have all the replaced by PTFE packing graphite packing, even to buy a new valve will also be replaced by one of the PTFE packing graphite packing after use. But the graphite filler also has a drawback, that is, back to the big, the beginning of some of the crawling phenomenon, this, manufacturers and operators in the design and installation of valve equipment should also be considered.
