Valve disc and seat part of the safety valve the sealing place if the leakage exceeds the rated range, then the loss of the medium will result in the damage of the sealing material. -As a case, the safety valve sealing surface mainly composed of metal materials, and the cost to do smooth and flat, but in the pressure of the media two times the case, to be strict with the full seal does not leak is unlikely. Therefore, in the rated pressure environment, steam as the medium of the safety valve can be simply based on the naked eye observation and ear to detect. The main causes of valve leakage are the following two points:

(1) The seal surface appears dirt and sundry, and so on, and the original seal of the plane to be separated, so that the spool and valve seat between the gap. Leakage caused by valve. To solve this kind of problem, usually is 淸 the dirt on the seal surface. But in the boiler temporarily stop use to prepare maintenance, must first carry on the safety gate to run the mound Test, once has the leakage phenomenon must overhaul. -The interval for running the mound is 20 minutes after the complete cooling.

(2) Breakage of sealing surface. The reasons are more, such as: first, the sealing materials unqualified. A safety valve in the use of many years after the very easy because of continuous switch running-in maintenance and other reasons, the strength of the seal surface is weakened, which leads to the ability to seal the weakened. The proposal to solve this problem is to flatted the original sealing surface and to weld it two times according to the original drawing to enhance the hardness and strength of the surface. But also pay attention to the superficial damage, must not be careless.

Second, the quality of maintenance. Due to the poor level of maintenance, the valve core and valve seat in the grinding process can not achieve a certain level. The solution is to repair the sealing surface as much as possible by means of grinding or even turning, depending on the severity of the damage.

Third, improper assembly or wrong parts size. In the whole assembly work, the valve core and the valve seat are not completely aligned, or in the bonding surface has appeared the serious light transmission problem, also may be the valve core and the valve seat's seal place is too loose, cannot truly seal. The solution is to strictly check the length and thickness of the gap near the spool and distribution, and to ensure that each part of the gap can not lift the valve core, according to the data on the drawings to reduce the width of the sealing surface to be properly sealed.