1. When the sanitary butterfly valve is in the medium opening position, the opening shape formed by the valve body and the front end of the butterfly plate is centered on the valve shaft, and different states are formed on both sides. One side of the butterfly plate front end moves in the direction of water flow, while the other side moves against the direction of water flow. Therefore, one side of the valve body and the valve plate form a nozzle shaped opening, and the other side forms a throttle hole shaped opening. The nozzle side has a much faster flow rate than the throttle side, and negative pressure is generated below the throttle side valve, often causing rubber seals to fall off.
2. Under normal use, the lifespan of the sealing seat of a sanitary butterfly valve is 10-15 years for rubber and 70-85 years for metal. The relationship between the opening and flow rate of sanitary butterfly valves with flow accuracy is basically a linear proportional change. If a sanitary butterfly valve is used to control flow, its flow characteristics are closely related to the flow resistance of the piping. For sanitary butterfly valves, if two pipelines are installed with the same valve diameter and form, but the pipeline loss coefficient is different, the flow rate of the valve will also vary greatly. If the valve is in a state of large throttling amplitude, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, it is used at an angle of 15 °.
3. The operating torque of sanitary butterfly valves varies due to differences in opening degree and valve opening and closing direction, especially for large-diameter valves. The torque generated by water depth and the difference between the upper and lower water heads cannot be ignored.