According to the valve plate contour, butterfly valves can be divided into traditional contour valve plate butterfly valves and dynamic contour valve plate butterfly valves. The characteristics of butterfly valve are as follows. 1. Large flow capacity, large adjustable ratio and low pressure drop. The butterfly valve has small flow resistance and can be used to manufacture large diameter butterfly valves. Its flow capacity is large, about 1.5~2 times that of other control valves with the same diameter. The adjustable ratio of butterfly valve with traditional contour valve plate is 33:1, and that of butterfly valve with dynamic contour valve plate is 100:1.
2. The flow characteristic is approximately equal percentage in the range of 0~70 ° (usually 0~60 ° for butterfly valves). When the specified angle is exceeded, the operation of the control valve will be unstable.

When in the fully open position, the thickness of the butterfly plate is the only 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. Butterfly valve has two sealing types: elastic seal and metal seal. For elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate. Metal sealed valves generally have longer service life than elastic sealed valves, 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 temperature limitation. Sealing type of butterfly valve.