Butterfly valve flow characteristics

The relationship between the opening and the flow of the butterfly valve is basically a linear proportional change. If it is used to control the flow, its flow characteristics are also closely related to the flow resistance of the piping. If the diameters and forms of the two pipeline installation valves are the same, and the pipeline loss coefficient is different, the flow rate difference of the valves will also be very large. If the valve is in a large throttling state, the back of the valve plate is prone to cavitation and may damage the valve. Generally, it is used outside 15°.

When the butterfly valve is in the middle opening degree, the shape of the opening formed by the front end of the valve body and the butterfly plate is centered on the valve axis, and the two sides form different states. The front end of the butterfly plate moves in the direction of the flowing water and the other side flows in the direction of the flowing water. Moving, therefore, one side of the valve body and the valve plate form a nozzle-like opening, the other side similar to the orifice-shaped opening, the nozzle side faster than the throttling side of the flow rate, and the throttle valve will produce negative pressure, often Rubber seals will come off.

Butterfly valve operating torque, due to opening and valve opening and closing direction of different values, horizontal butterfly valve, especially large-diameter valve, due to water depth, the shaft shaft, the head of the water generated by the torque can not be ignored. In addition, when the elbow of the inlet side of the valve is deflected, the bias flow will increase and the torque will increase. When the valve is in the middle opening, the operating mechanism needs to be self-locking due to the effect of the water flow torque.