Valve leakage causes and treatment methods

If the leakage of the valve beyond the rated range occurs in the sealing valve and valve seat part of the safety valve, the loss of the medium will occur and the sealing material will be destroyed. Under normal circumstances, the sealing surface of the safety valve is mainly composed of metal materials, and it is costly and smooth to complete, but in the case of secondary pressurization of the medium with pressure, it is unlikely to be completely sealed without leakage. of. Therefore, in the rated pressure environment, the safety valve using steam as a medium can be detected by naked eye observation and ear hearing. The valve is mainly due to the leakage of the following two:


(1) Dirty dirt, debris, etc., are formed on the sealing surface, and the originally sealed surface is blocked and blocked, resulting in a gap between the valve plug and the valve seat, resulting in leakage of the valve . To solve this type of problem, it is common to dispose of dirt and debris on the sealing surface. When the boiler is temporarily decommissioned for maintenance, it is necessary to conduct a running test on the safety door first, and if there is a leakage phenomenon, it must be overhauled. The interval between runs is 20 minutes after cooling completely.


(2) Damage to the sealing surface. There are many reasons, such as: First, the material used for sealing is not qualified. After a safety valve is used for many years, the strength of the sealing surface is easily weakened due to continuous switching and overhauling, and the sealing ability is weakened. The recommended measure to solve this problem is to flatten the original sealing surface and perform secondary processing welding according to the original drawings to enhance the hardness and strength of the surface. Also pay attention to the damage on the surface, must not be sloppy.


The second is maintenance quality. Due to the poor level of maintenance, the valve plug and the valve seat cannot reach a certain level in the grinding process. The solution is to use grinding or even turning, depending on the severity of the damage, to repair the sealing surface as much as possible.


Third, improper assembly or incorrect part size. In the entire assembly work, the valve plug and the valve seat are not completely aligned, or there is a serious light transmission problem on the bonding surface. It is also possible that the sealing of the valve plug and the valve seat is too loose to be truly sealed. The solution is to strictly check the length and distribution of gaps next to the valve core, and to ensure that the gap can not be lifted in each part, according to the data on the drawings to appropriately reduce the width of the sealing surface for sealing.