6) Adjust the friction force of butterfly valve plate to overcome the "O" ring, seal ring, lining and other soft sealed butterfly valves used in the opening and jumping method. When the valve is closed, due to the deformation of soft seals, the valve plate is closed in place and encloses the valve plate, which can achieve a very ideal cutting effect. However, when the valve is to be opened, the force of the actuator to open the valve plate is constantly increasing. When the friction between the soft seal and the valve plate is equal, the valve plate starts. Once started, the friction force decreases sharply. In order to achieve force balance, the valve plate opens violently. When this force balances the unbalanced torque acting on the medium of the corresponding opening with the opening torque of the actuator, the valve stops at this opening. The opening of this violent and sudden jump can be as high as 30-50%, which will cause a series of problems. At the same time, due to the large change of soft seals during closing, it is easy to produce deformation, damage by the valve plate, strain, etc., which will affect the service life. The solution is to adjust the friction force between the soft seal and the start of the valve plate, which can not only ensure that the required cut-off requirements are met, but also enable the valve to start normally. The specific methods are: ① Adjust the interference; ② By limiting or adjusting the preload and output force of the actuator, the difficulty of opening caused by excessive closing of the valve plate can be reduced.

(8) As a pneumatic valve, the main power source is gas, usually 0.2-0.8MPa, which is relatively safe. In case of air leakage of the pneumatic switch ball valve, the gas can be discharged directly without polluting the environment. In short, the safety is relatively high.