Resolution valve leakage and valve sealing performance factors

Assessment of the valve is the valve sealing performance merits of the main indicators of quality. Valve sealing performance mainly include two aspects, namely, leakage and leakage.
Endoleak refers to the closure member between the valve seat and sealing of the media reach, assessment criteria within the country there are two missing. One is the State Technical Supervision Bureau released in December 2008, July 1, 2009 began implementation of national standards GB/T13927-2008 "industrial valve pressure test." This standard is used with reference to the international standard ISO5208-2007 "Industrial valves valve pressure test" develop and the other is issued by the Ministry of Machinery Industry JB/T9092-1999 "valve testing and inspection," This standard is referenced to meet API598- 1986 "valve inspection and test" developed. GB/T13927-2008 for general industrial valves inspection; JB/T9092-1999 industrial valves for the oil inspection.
Leakage refers to the parts of the stem packing leak, the leak in the flange gasket and valve parts casting defects caused due to leakage, leakage is simply not allowed. If the media is not allowed into the atmosphere, then the leakage of indicative seals leakage than the inner seal more important. Therefore, the valve sealing performance should lead to the manufacturer's attention.
⑴ quality sealing surface of the valve sealing performance of the sealing surface of the valve seat and the closure member is in contact with each other to shut down part. When the sealing surface pressure at 40MPa or less, the quality of the sealing surface of the valve sealing performance play a decisive role. This is because: When the sealing surface pressure is small, low surface roughness, the leakage is increasing rapidly. When the sealing surface pressure is large, the surface roughness on the leakage has been significantly reduced.
⑵ width on the valve sealing surface of the sealing performance of the sealing surface width determines the length of the pores. When the width is increased, fluid movement along the pores stroke lengthened to increase the resistance movement. Can be reduced to increase the width of the sealing surface pressure in the valve erosive wear. Increase the width of the bolt seals sealing surface, it will cause leakage increased in proportion to the stroke length, and thus be able to proportionately reduce leakage. But the sealing surface width increases, in the same sealing force, the sealing pressure than decreases, but also make the possibility of leakage increases. Therefore, the increase can not be unlimited sealing surface width.