Sudhanafluid pneumatic valve series: butterfly valve The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. In the cylindrical channel of the butterfly valve body, the disc shaped butterfly plate rotates around the axis with a rotation angle of 0 �°~90 �°. When the rotation angle reaches 90 �°, the valve is fully open. The butterfly valve is simple in structure, small in volume and light in weight, and only consists of a few parts. Moreover, the valve can be quickly opened and closed only by rotating 90 �°, which is simple to operate. At the same time, the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. The butterfly valve has two sealing types: elastic seal and metal seal. For elastic sealing valves, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate. The valve with metal seal is generally longer than the valve with elastic seal, but it is difficult to achieve complete sealing. The metal seal can adapt to higher working temperature, while the elastic seal has the defect of being limited by temperature. If the butterfly valve is required to be used for flow control, the main thing is to correctly select the size and type of the valve. The structure principle of butterfly valve is especially suitable for making large diameter valves. Butterfly valves are not only widely used in petroleum, gas, chemical industry, water treatment and other general industries, but also used in the cooling water system of thermal power plants. There are two kinds of butterfly valves commonly used: wafer type butterfly valve and flange type butterfly valve. Wafer type butterfly valve uses stud bolts to connect the valve between two pipe flanges. Flange type butterfly valve has flanges on the valve, and bolts are used to connect the flanges on both ends of the valve to the pipe flanges.