Main features and uses 1, compact structure, reasonable design, good valve rigidity, smooth passage, flow resistance coefficient is small. 2, the sealing surface of stainless steel and carbide, long service life 3, the use of flexible graphite packing, reliable sealing, light and flexible operation 4, the driving mode sub-manual, electric, pneumatic, gear power, structure type: Plate, rigid wedge single gate and double gate type. 5, Widely used in petroleum chemical industry, thermal power plants and other oil products, water vapor pipeline for access or cut off the medium pipeline opening and closing devices.