Industry News

Leakage of bearing seal

Update:Jan 2018,31
Summary:

• Under normal working pressure of the equipment, the v […]

• Under normal working pressure of the equipment, the valve flap and seat sealing surface occur more than the allowable degree of leakage, bearing seal leakage will not only lead to loss of media. In addition, the continuous leakage of media will make the hard sealing material is damaged, but the sealing surface of the common bearing seals are metal materials on the metal material, although strive to make it smooth and neat, but in the case of medium pressure To be absolutely leak is also very difficult. Therefore, the working medium is a steam bearing seals, under the specified pressure value, if the naked eye at the exit can not see, there is no leakage, it is considered the sealing performance is acceptable. The general causes of leakage of the main reasons for the following three cases:
• In one case, dirt contaminates the sealing surface and cushions the sealing surface. Caused by a gap between the spool and the valve seat, so the seal leakage. The way to eliminate this kind of failure is to remove the dirt and impurities falling on the sealing surface. Generally, when the size of the wind turbine is about to be shut down, the safety door running test should be conducted firstly. If the leakage is found, If it is run furnace after the furnace runaway test found leakage of the security door, it is estimated that this caused the situation, you can run 2 hours later run cooling rudder once again, on the sealing surface erosion.
• In the other case, the sealing surface is damaged. Seal surface damage caused by the following main reasons: First, poor sealing surface material. For example, the main safety door due to years of overhaul, the main safety valve seat and seat sealing surface has generally been studied very low, so that the sealing surface hardness is greatly reduced, resulting in decreased sealing performance, the best way to eliminate this phenomenon is The original sealing surface turning down, and then re-welding the drawings required processing to improve the sealing surface hardness. Note that in the processing must ensure the quality of processing, such as the sealing surface cracks, trachoma and other defects must be machined back after processing. Newly processed valve seat must meet the drawing requirements. Second, the poor quality of maintenance, valve seat grinding can not meet the quality standards, the way to eliminate this failure is based on the degree of injury using grinding or turning grinding method to repair the sealing surface.
• Another cause of bearing seal leaks is due to improper assembly or inappropriate parts dimensions. In the assembly process, the valve seat is not fully aligned or the surface with light transmission phenomenon, or the valve seat sealing surface is too wide, which is not conducive to sealing. Elimination method is to check the spool around the size and uniformity of the gap to ensure that the valve core tip hole and the sealing surface with a positive, check the Ministry of the gap does not allow lift valve, according to the drawings required to reduce the width of the sealing surface to achieve effective sealing .