The working principle of butterfly valve

Butterfly valve is a kind of valve which uses the round butterfly plate as the opening and closing parts and turns with the stem to open, close and adjust the fluid channel The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, with the rotation angle between 0 ° and 90 ° When it rotates to 90 °, the valve will be fully open Butterfly valve has the characteristics of simple structure, small volume, light weight, low material consumption, small installation size, fast switch, 90 ° reciprocating rotation, small driving torque, etc it is used to cut off, connect and regulate the medium in the pipeline, with good fluid control characteristics and closing sealing performance When the butterfly valve is in the fully open position, the butterfly plate thickness is the resistance of the medium flowing through the valve body, so the pressure drop generated by the valve is very small, so it has better flow control characteristics Butterfly valve has two types of seal: elastic seal and metal seal Elastic sealing valve, sealing ring can be inlaid on the valve body or attached to the periphery of butterfly plate The service life of the valve with metal seal is generally longer than that of the valve with elastic seal, but it is difficult to achieve complete seal The metal seal can adapt to the higher working temperature, while the elastic seal has the limitation of temperature If butterfly valve is required to be used as flow control, the main thing is to correctly select the size and type of valve The structure and principle of butterfly valve is especially suitable for making large-diameter valve Butterfly valve is not only widely used in petroleum, gas, chemical industry, water treatment and other general industries, but also in the cooling water system of thermal power station There are three kinds of butterfly valves commonly used: wafer butterfly valve, flange butterfly valve and butt welding butterfly valve The wafer butterfly valve is connected between two pipe flanges with stud bolts; the flange butterfly valve is equipped with flange on the valve, and the flange on both ends of the valve is connected on the pipe flange with bolts; the two ends of the butt welding butterfly valve are welded with the pipe The streamlined design of butterfly plate makes the loss of fluid resistance small, which can be described as an energy-saving product The valve rod is a through rod structure After tempering treatment, it has good comprehensive mechanical properties, corrosion resistance and scratch resistance When the butterfly valve is opened and closed, the valve rod only rotates without lifting, the packing of the valve rod is not easy to be damaged, and the sealing is reliable It is fixed with the taper pin of the butterfly plate, and the extension end is designed to prevent the valve rod from bursting out when the valve rod is accidentally broken at the connection of the valve rod and the butterfly plate.