(1) appear on the sealing surface of dirt and debris, etc., and the original seal of the plane blocked, so that between the valve core and the valve seat gap, leading to leakage of the valve. To solve this kind of problem, it is usually the dirt on the seal. And temporarily suspended in the preparation of the maintenance of the boiler, the first safety door to run the mound test, once the leakage phenomenon will be the overall maintenance. - The distance between the running mound is 20 minutes after the complete cooling.
(2) damage to the sealing surface. More reasons, such as: First, the sealing material with the failure. One side of the safety valve after years of use, easily due to continuous switching and running and other reasons caused by the sealing surface strength is weakened, and thus lead to the ability to seal is weakened. The recommended measure to solve this problem is to cut the original sealing surface, and according to the original drawings for secondary processing welding, enhance the surface hardness and strength. But also pay attention to the surface damage, must not sloppy.
Second, maintenance quality. Due to the level of maintenance, resulting in spool and valve seat in the grinding process can not reach a certain level. The solution is to repair the sealing surface as much as possible by the use of grinding or even turning.
Third, improper assembly or part size is wrong. In the whole assembly work, the spool and the valve seat is not fully aligned, or in the joint surface there is a serious light transmission problems, there may be spool and seat seal is too loose, it is difficult to really sealed. The solution is to strictly check the spool next to the length of the gap thickness and distribution, and to ensure that the parts of the gap can not lift the spool, according to the data on the drawings to reduce the width of the sealing surface to seal.