First, what is internal leakage? Internal leakage refers to the degree of sealing between the valve seat and the closing member against the medium. The assessment standards currently in use include GB/T13927, which was released by China's State Administration of Technical Supervision in December 2008 and came into effect on July 1, 2009. -2008 "Industrial Valve Pressure Test", and the other is JB/T9092-1999 "Valve Testing and Inspection" issued by the former Ministry of Machinery Industry. The difference between the two is that GB/T13927-2008 is suitable for the inspection of general industrial valves , and JB/T9092-1999 is suitable for the inspection of valves used in the petroleum industry.
So what is leakage? External leakage refers to leakage from the valve stem packing area, leakage from the middle flange gasket area and valve body leakage caused by casting defects. If the medium is not allowed to be discharged into the atmosphere, the sealing of external leakage is more important than the sealing of internal leakage. Zhongmei Valve tells you that generally speaking, the main factors that will affect the sealing performance of the valve are as follows: sealing surface quality, sealing surface width, pressure difference between the front and back of the valve, sealing surface material, medium properties, surface hydrophilicity, sealing There are 8 factors including the presence or absence of oil film and the rigidity and structural characteristics of the closing parts.
