Structural characteristics of the ventilation butterfly valve 1, the use of a new structure of the mid-line disc and short structural steel welded design and manufacture of compact structure, light weight, easy to install, small flow resistance, large liquidity. Operation is light 2, there is no connecting rod, bolts, etc., reliable, long service life. Can be installed in multiple stations, not affected by the media flow widely used in building materials, metallurgy, mining, electricity and other production processes Medium temperature ≤ 300 ℃ Nominal pressure of 0.1Mpa pipe, use: The butterfly valve is a non-closed butterfly valve. To connect, open or close the media volume. The working principle of the ventilation butterfly valve Ventilation butterfly valve driven by the motor drive actuator, the disc in the 90 ° range of free rotation in order to achieve opening and closing or regulating the purpose of the media flow. Lined rubber butterfly valve as a system used to achieve on-off and flow control of the pipeline components, has been in the petroleum, chemical, metallurgical, hydropower and many other fields have been very widely used. Known butterfly valve technology, the use of more sealed form the seal structure, seal information for the rubber, PTFE and so on. Due to the structural characteristics of the restrictions, do not meet the high temperature, high pressure and corrosion-resistant, anti-wear and other industries. A more advanced butterfly valve is a three eccentric metal seal butterfly valve, the valve body and valve seat for the joint member, the outer surface of the valve seat sealing temperature welding, corrosion resistant alloy material. Multi-layer soft stacked ring fixed to the valve plate, the butterfly valve compared with radical butterfly valve has high temperature, light operation, opening and closing without friction, closing with the torque of the transmission mechanism to compensate for increased sealing, improved butterfly valve The sealing performance and extend the service life of the advantages. Ventilation butterfly valve Classification construction, device points 1 device location, height, direction of import and export must meet the design requirements, pay attention to the flow direction of the medium should be consistent with the direction of the arrow marked by the valve body, the connection should be strong and tight. 2 valve device before the appearance of the inspection, the valve nameplate should be consistent with existing national norms "General Valve Marking" GB12220 regulations. For the working pressure is greater than 1.0MPa and the main pipe to play the role of cut-off valve, the device should be carried out before the intensity and tightness test, qualified after the standard use. Strength test, the test pressure of 1.5 times the nominal pressure, the duration of not less than 5min valve housing, packing should be no leakage as qualified. Tightness test, the test pressure of 1.1 times the nominal pressure; test continued for a long time in line with the requirements of GB50243 Ventilation butterfly valve according to the working pressure classification 1 vacuum butterfly valve working pressure is lower than the standard reactor atmospheric calendar butterfly valve. 2 low pressure butterfly valve. Nominal pressure PN <1.6MPa butterfly valve. 3 medium pressure butterfly valve. Nominal pressure PN 2.5 - 6.4MPa butterfly valve. 4 high-pressure butterfly valve. Nominal pressure PN is 100--80.0MPa butterfly valve. 5 ultra-high pressure butterfly valve. Nominal pressure PN> 100MPa butterfly valve. Ventilation butterfly valve temperature by temperature classification 1 high temperature butterfly valve. T> 450 ℃ butterfly valve 2 temperature valve. 120C <t <450C butterfly valve 3 room temperature. A 40C <t 4 low temperature butterfly valve. A 100 <t <a 40C butterfly valve ultra-low temperature butterfly valve. t <a 100C butterfly valve ventilation butterfly valve according to the connection type 1 pairs of butterfly valve 2 flange butterfly valve 3 ear butterfly valve 4 welded butterfly valve ventilation butterfly valve according to the structure classification 1 center seal butterfly valve 2 single eccentric seal coal valve 3 double eccentric sealing butterfly valve 4 three eccentric seal 跺 valve ventilation butterfly valve seal material classification 1 soft seal butterfly valve. 2 sealed by the non-metallic soft materials on the non-metallic soft materials. 3 sealed by the hard metal materials on the non-metallic soft materials. 4 metal seal butterfly valve. Seal by the metal hard material on the hard metal material composition.