The butterfly valve is generally less than 90 ° from full opening to full closing, and the butterfly valve and butterfly stem have no self-locking capacity. In order to position the butterfly plate, a worm gear reducer should be installed on the valve stem. The use of worm gear reducer can not only make the butterfly plate have self-locking ability, make the butterfly plate stop at any position, but also improve the operating performance of the valve.

With the application of chemical resistant synthetic rubber in butterfly valves, the performance of butterfly valves has been improved. Because synthetic rubber has the characteristics of corrosion resistance, erosion resistance, stable size, good resilience, easy forming and low cost, and can choose synthetic rubber with different properties according to different use requirements to meet the operating conditions of butterfly valves, it is widely used to manufacture lining and elastic seat of butterfly valves.