For pneumatic ball valves with operating temperature lower than 260 (500F), non-metallic sealing rings can be used. When the working temperature is 538c (1000T), the most common sealing measure is to install a graphite seal ring into the metal retainer ring. This sealing structure is often used in the on-off operation of pipelines. Small high-temperature pneumatic ball valve is in on-off and throttling operation. Metal sealing rings are often used. The sealing ability of the metal sealing ring is the key to whether the pneumatic ball valve can be dumped in the high-temperature and high-pressure pipeline. Now it has been successfully solved by carefully processing the sealing groove and the surface of the ball. For corrosion resistance and abrasion resistance of materials, hard bench metal shall be coated to meet the requirements of valves with diameters of more than 2 inches. Valve body materials and pressure shall be subject to service temperature. Work pressure or both impose strict restrictions.

Structure enhancement measures of pneumatic butterfly valve
The pneumatic butterfly valve used to compensate the tank foundation subsidence and the hose with small lateral compensation and large bending radius used in other places abroad mainly adopt the construction mode of corrugated pipe armored steel belt mesh sleeve.
To analyze the strength of the metal wire mesh sleeve, first make clear the structural parameters and the relationship between them.
The net sleeve is made of several strands of metal wires with diameter d, each of which has several wires. It is wrapped on the cylindrical surface of the corrugated pipe with certain rules.
Therefore, in order to reasonably use the strength of the metal wire mesh sleeve, it is necessary to understand the bearing capacity of the bellows.
Since the rubber hose with wire mesh sleeve as the "tendon" is the predecessor of modern pneumatic butterfly valve, before analyzing the strength of the wire mesh sleeve of modern pneumatic butterfly valve, let's first discuss the condition of the wire mesh of the rubber hose under the stress condition. The rigidity of the rubber hose is very small, so the load caused by the medium pressure is basically accepted by the wire mesh. Pneumatic butterfly valves are different from rubber hoses because their lateral stiffness is much greater than the longitudinal stiffness. Therefore, a large part of the transverse load caused by the medium pressure is accepted by the bellows, while the longitudinal load is mainly accepted by the wire mesh.