The 47/48-21000W series pneumatic single seat bellows sealed regulating valve is a product developed on the basis of digesting and absorbing advanced foreign technology.

The 47/48-21000W series products consist of ∑ F pneumatic actuators and 21000W series single seat bellows sealed valves, with strong resistance to differential pressure. The 97/98-21000W series products are composed of pneumatic thin film multi spring actuators and 21000W series single seat bellows sealed valves, with small overall volume and light weight. The difference between the two lies in the use of different actuators with the same valve components.