Butterfly valve refers to the closure (valve or disc) for the disc, around the valve shaft to open and close a valve, cut off and throttling in the pipeline. Butterfly valve body material: cast iron, cast steel, stainless steel, chrome molybdenum steel, aluminum alloy, brass, sealing surface Material: H, J, F46, Y, W. Working pressure 0.6-10MPA, operating temperature -40 ° C- 550 ° C. Valve diameter DN15-DN1000. Connection: flange, welding, the folder. Transmission: manual, worm, pneumatic, electric. Applicable medium: water, oil, gas, steam, mud water, acids and so on. Manufacturing standards: (configuration of the flange standard) GB, American Standard, Japanese standard. Ventilation Butterfly Valve The opening and closing member is a disc-shaped disc that rotates about its own axis within the valve body to open or close or adjust. The butterfly valve fully open to the whole is usually less than 90 °, the butterfly valve and the butterfly itself does not have self-locking ability, in order to disc positioning, to install a worm reducer on the stem. The use of worm reducer, not only can make the disc self-locking ability to stop the butterfly plate in any position, but also to improve valve performance. Industrial butterfly valve features high temperature, high pressure range, the valve nominal diameter, the valve body made of carbon steel, the valve ring using a metal ring instead of rubber ring. Large high temperature butterfly valve welded steel manufacturing, mainly for high temperature medium smoke duct and gas pipelines.