Butterfly valve, also called flap valve, is a simple structure of the regulator, but also can be used for low pressure pipeline medium switch control. It refers to a valve whose closing part (disc or disc) is a disc that rotates around the valve shaft to open and close. It is mainly used for cutting and throttling on the pipeline. Butterfly valve opening and closing parts is a disc shaped butterfly plate, in the valve body around its own axis rotation, so as to achieve the purpose of opening and closing or adjustment