Eccentric electric butterfly valve, also known as flapper valve, is a simple structure of the control valve, can be used for low-pressure pipe medium switch control of the butterfly valve is refers to the closing parts (disc or disc) for the disc, a valve that rotates around the valve shaft to open and close. Valves can be used to control air, water, steam, a variety of corrosive media, mud, oil, liquid metal and radioactive media and other types of fluid flow. In the main pipe cut off and throttling. The butterfly valve open-close piece is a disc-shaped butterfly plate, which rotates around its own axis in the valve body, thus achieves the open-close or the adjustment goal.