Sanitary butterfly valve is widely used, there are many advantages, but it still has certain defects, the following is to introduce what defects sanitary butterfly valve has.

1. When the sanitary butterfly valve is in the middle opening, the opening shape of the front end of the valve body and butterfly plate is centered on the valve shaft, and the two sides form different states. The front end of the butterfly plate on one side moves along the flow direction, and the other side moves against the flow direction. Therefore, one side of the valve body and the valve plate form a nozzle shaped opening, and the other side is similar to a throttle orifice type opening, and the flow rate of the nozzle side is faster than that of the throttling side However, negative pressure will be generated under the throttle side valve, and the rubber seal will often fall off.

2. In normal use, the life of seal seat of sanitary butterfly valve is 10-15 years for rubber and 70-85 years for metal. The relationship between the opening of sanitary butterfly valve and flow rate is basically linear proportional change. If sanitary butterfly valve is used to control the flow, its flow characteristics are closely related to the flow resistance of the piping. If the sanitary butterfly valve is installed in two pipelines, the diameter and form of the valve are the same, and the pipeline loss coefficient is different, the flow rate of the valve will be greatly different. If the valve is in a large throttling range, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, it is used outside 15 ℃.

3. The operating torque of sanitary butterfly valve is different due to the difference of opening and closing direction. Especially for large diameter valve, the torque caused by water depth and head difference between upper and lower water can not be ignored.