An electric ventilation valve has a simple structure, small size, light weight, material consumption province, small installation size, switch quickly, 90 ° reciprocating rotary drive torque characteristics of small, used to cut, turn, adjust the line of medium, having good fluid sealing properties and closing control characteristics. 2, the electric ventilation valve can carry mud accumulation of fluid in the pipe mouth least. Under low pressure, can achieve a good seal. Regulation performance. 3, streamline design electric ventilation valve disc, so that the loss of fluid resistance, can be described as an energy-saving products. 4, electric ventilation valve stem to pass pole structure, after quenching, with good mechanical properties and corrosion resistance, scratch resistance. Electric butterfly valve opening and closing the valve stem when only rotational movement without making lifting operation, the valve stem packing is not easy to destroy, reliable sealing. And disc taper pin fixed, extended end to prevent out design, in order to avoid the stem and disc connected to the stem of the accident when the collapse of the fracture. 5, the electric ventilation valve connections are flanged, wafer, welded connections and lug wafer connection. Drive in the form of a manual, worm gear, electric, pneumatic, hydraulic, electro-hydraulic actuator linkage, enabling remote control and automation. Advantages: 1, electric ventilation valve open and close easily and quickly, saving, fluid resistance, can often operate. 2, the electric ventilation valve structure is simple, small size and light weight. 3, the electric ventilation valve can carry mud accumulation of fluid in the pipe mouth least. 4, electric low pressure vent valve, can achieve a good seal. 5, the electric ventilation valve regulated performance. Disadvantages: 1, using a small range of pressure and temperature. 2, sealing poor. Electric ventilation butterfly form of the structure can be divided into bias plate, vertical plate, inclined plate and leveraged. Press the seal can be divided into soft and hard seal sealed two. Soft sealing type commonly used rubber ring seal, seal type commonly used hard metal ring seal. By connection type can be divided flange connections and clamp connections; can be divided according to the manual transmission, gear transmission, pneumatic, hydraulic and electric several.