Who can talk about the standard of valve leakage grade?

In the process of valve use, because different models of Weidun TVON valves have different leakage grade standards, customers often report internal leakage. In order to facilitate customers to understand and choose the appropriate control valve, the leakage grade is briefly introduced. The leakage standard of Wheaton VTON valve is formulated according to foreign ANSI-B16.104 FCI 70-2. The corresponding domestic standards are GBT/ 172 13.4 and GB42 13. The leakage grade is divided into six grades: I, II, III, IV, V and VI.

The first level means that the control valve is designed according to the basic type, and the second, third and fourth levels can be modified. According to the agreement between users and suppliers, testing is not required.

Class II leakage is 0.5% of the rated capacity of the valve × generally requires two-seat regulating valve and sleeve regulating valve with balanced structure. The sealing surface is a metal hard sealing structure.

Three-stage leakage is 0. 1%× rated capacity of the valve, which is generally a two-seat control valve and a balanced sleeve control valve. The sealing surface is a metal hard sealing structure. Slightly higher than the requirements of the second level.

Ⅳ leakage is 0.0 1%× rated capacity of the valve, which is generally a single-seat regulating valve and a special sealing sleeve regulating valve. This is a common leakage level.

Class V leakage is 0.05% ml/min. in. lb/sq. in general, it is a single-seat regulating valve and a sleeve regulating valve with special seal. The maximum working pressure difference was used in the test. Weidun VTON's valves generally have a leakage level of V-class.

Class ⅵ leakage is bubble level, and the leakage is small. Seat seals are usually elastic seats. Witton VTON valve requires high leakage grade VI, which is used in occasions with high sealing leakage requirements. That is, o leakage