Butterfly valves can be divided into pneumatic butterfly valves, electric butterfly valves, manual butterfly valves, etc. The butterfly valve is a valve that uses a circular butterfly plate as an opening and closing part and rotates with the valve stem to open, close and adjust the fluid passage. The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical passage of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When the rotation reaches 90°, the valve is fully opened. Butterfly valve, also called flap valve, is a kind of regulating valve with simple structure. It can also be used for on-off control of low-pressure pipeline media. Butterfly valve refers to a kind of valve whose closing part (disc or butterfly plate) is a disc, which rotates around the valve shaft to achieve opening and closing. It is mainly used for cutting off and throttling on the pipeline. The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose of opening and closing or adjustment. The butterfly valve is usually less than 90° from fully open to fully closed. The butterfly valve and the butterfly stem have no self-locking ability. For the positioning of the butterfly plate, a worm gear reducer should be installed on the valve stem. The use of worm gear reducer can not only make the butterfly plate have self-locking ability, make the butterfly plate stop at any position, but also improve the operation performance of the valve. The industrial butterfly valve is characterized by high temperature resistance, high applicable pressure range, large nominal diameter of the valve, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of a rubber ring. The large high temperature butterfly valve is made of steel plate welding, and is mainly used for flue ducts and gas pipes of high temperature media.

Butterfly valves can be divided into offset plate type, vertical plate type, inclined plate type and lever type according to the structure. According to the sealing form, it can be divided into two types: relatively sealed type and hard sealed type. The soft seal type generally uses a rubber ring seal, and the hard seal type usually uses a metal ring seal. According to the connection type, it can be divided into flange connection and wafer connection; according to the transmission mode, it can be divided into manual, gear transmission, pneumatic, hydraulic and electric.