How to control the flow of the vacuum butterfly valve

The relationship between the opening degree of the vacuum butterfly valve and the flow rate changes substantially linearly. If it is used to control the flow, its flow characteristics are closely related to the flow resistance of the piping. For example, the diameters and forms of the two pipe installation valves are all the same, and the pipe loss coefficient is different, and the valve flow difference is also large.

If the valve is in a state of large throttle, the back of the valve plate is prone to cavitation and may damage the valve, and is generally used outside of 15°.

When the butterfly valve is at the middle opening degree, the shape of the opening formed by the valve body and the front end of the butterfly plate is centered on the valve shaft, and the two sides are formed to complete different states. The front end of the butterfly plate moves along the water direction and the other side flows in the opposite direction. Therefore, one side of the valve body and the valve plate form a nozzle-like opening, and the other side is similar to the orifice-shaped opening, the nozzle side is much faster than the throttle side, and the negative pressure is generated under the throttle side valve, often A rubber seal will come off.

The operating torque of the butterfly valve varies depending on the opening degree and the direction of opening and closing of the valve. Horizontal butterfly valves, especially large-diameter valves, cannot be ignored due to the water depth and the head difference between the valve shaft and the head. In addition, when the valve inlet side device is bent, a bias current is formed and the torque is increased. When the valve is at the intermediate opening, the operating mechanism needs to be self-locking due to the action of the water flow torque.