Chemical production is often carried out under certain temperature and pressure conditions, and the process is strictly required. The materials involved are various gases, liquids and solids, and the properties are different, and various types of production equipment are needed. However, the equipment contacted with the medium is corroded at all times in production, thus seriously restricting the development of chemical industry and so on. When science and technology are not developed, people always look for anti-corrosion agents in metals. But these devices tend to be expensive, and do not solve many of the problems of corrosion. Later, people began to explore the use of non-metal resources to replace metal. Plastics are first applied to polyvinyl chloride in China, followed by polytetrafluoroethylene, PTFCE, Polyperfluoroethylene propylene and other fluorinated plastics.
Other polytetrafluoroethylene products, seals, in terms of heat resistance and chemical resistance, polytetrafluoroethylene is a good sealing material
. But as a sealing material, it must also have compressibility, so cold flow is the biggest drawback. Polytetrafluoroethylene seal material has poor reduction capability, so it needs to be considered from the design of seal structure to improve its compressive resistance.
Bellows and Teflon bellows is easy to bend, flexible, it can make up for the disadvantages of difficult assembly of thrust tube, it can adapt to the small change in length. It can not only absorb the motion and vibration along the pipe and related machines, it also has the advantages of saving space, installing fast and so on. There are two main forms of Teflon bellows. The corrugated tube has high winding and ductility and is suitable for low pressure applications. Thermoforming bellows are suitable for low and medium pressure applications.