The centering shaft of the semi pneumatic ball valve disc adopts the static seal between the adjusting pad and the gland. The valve stem made of stainless steel adopts a double-layer sealing structure (Figure 4), because the valve stem is only 9O. Reciprocating motion makes the packing wear less. Under normal working conditions, the opening and closing times can reach 0.6~10000 times. The valve rod torque is MF valve rod torque, the valve rod torque when N mmM0F is closed N mmMF1r friction torque between packing and valve rod, the friction torque in N mmMZc bearing, and the wall thickness of N mm valve body is calculated according to the calculation formula of ANSI B16.34 wall thickness, or selected by referring to the wall thickness data specified in JB/T 7745.

The pneumatic fluorine lined butterfly valve and anti-corrosion fluorine lined butterfly valve adopt the combination of two halves of valve body, and the valve seat and valve body lining are integrated. When the valve is working, only the full plastic valve seat and the plastic lined butterfly plate are in contact with the medium, and the product can withstand the corrosion of any medium except molten alkali metal and element fluorine. Among them, D71F46 valve rod and butterfly plate (forged) are integrated, and the surface is evenly coated with a layer of FEP. The inner surface of the valve body channel is smooth, the fluid resistance is small, the CV value is high, the flow capacity is strong, and the torque is moderate. The four stage sealing structure is adopted, and the temperature resistant and anti-aging SI rubber elastic gasket valve seat is equipped outside the sealing surface, completely achieving zero leakage of the medium.