The pneumatic fluorine-lined butterfly valve is a special type of valve that is widely used in the industrial sector. The following is an in-depth introduction to the pneumatic fluorine-lined butterfly valve: 

1. Definition and Alias 

Pneumatic fluorine-lined butterfly valve, also known as pneumatic lined anti-corrosion butterfly valve, is a type of valve equipped with a butterfly plate coated with polytetrafluoroethylene (PTFE) on a spherical sealing surface. This valve is driven by an air actuator to achieve the functions of quick shut-off or flow regulation. 

2. Working Principle 

The working principle of the pneumatic fluoroplastic butterfly valve is based on the drive of the pneumatic actuator and the sealing performance of the fluoroplastic liner. The pneumatic actuator receives control signals (such as 4-20mA current signal or 0-10V voltage signal), converting the force of compressed air into mechanical energy. This mechanical energy drives the valve stem to rotate, thereby causing the butterfly plate to rotate 90 degrees within the valve body. The rotation of the butterfly plate achieves the opening and closing of the valve, thereby controlling the flow of the fluid. The fluoroplastic liner forms a sealing barrier between the butterfly plate and the inner wall of the valve body, effectively preventing the leakage of the medium. 

3. Features and Advantages 

High corrosion resistance: The fluoroplastic lining has excellent anti-corrosion properties and can withstand the erosion of various corrosive media, especially suitable for applications involving strong corrosive media such as acids and alkalis. 

Good sealing performance: The fluoroplastic lining forms a tight seal structure with the butterfly plate, ensuring no leakage when the valve is closed. 

Quick opening and closing: The pneumatic actuator features powerful driving force and fast response, enabling the valve to open and close rapidly. 

Novel design: The pneumatic fluorine-coated butterfly valve features a novel, rational design with a unique structure. It is lightweight, easy to install and maintain. 

Wide application range: It can be used for various media, including corrosive media, high-temperature media, as well as gas, liquid and solid particle media. 

4. Classification and Connection Methods 

The pneumatic fluoroplastic butterfly valves are classified by connection method into pneumatic flanged fluoroplastic butterfly valves and pneumatic socket-type fluoroplastic butterfly valves. In addition, according to the working conditions, either the switch-type or the regulating-type actuator can be selected. 

5. Classification and Connection Methods 

Pneumatic fluorine-coated butterfly valves are widely used in the regulation and flow control of media in industries such as chemical engineering, pharmaceuticals, petroleum, and food. They are particularly suitable for applications in harsh environments such as those found in the petrochemical, power, and steel industries. Additionally, they are also applicable in situations where solid particle media, such as dust, particles, and fibers, need to be conveyed. 

6. Important Notes 

Although the pneumatic fluorine-coated butterfly valve has excellent corrosion resistance and sealing performance, it has significant limitations in terms of temperature. Generally, it is suitable for media within the range of -50℃ to 150℃ (or -50℃ to 180℃). 

For process media with excessively high temperatures and pressures or those containing particulate matter, it is advisable to choose pneumatic fluoroplastic butterfly valves with caution. In some cases, it might be necessary to consider using butterfly valves with metal sealing materials. 

In conclusion, the pneumatic fluoroplastic butterfly valve, with its unique corrosion resistance and sealing performance, plays a significant role in the industrial field. When choosing and using it, a reasonable selection should be made based on specific working conditions and requirements.