A plug valve is a valve that uses a plug body with a hole as the opening and closing part and realizes the opening and closing action through the rotation of the plug body and the valve stem. The plug valve features a simple structure, quick opening and closing, and low fluid resistance. In recent years, as one of the earliest valves adopted by people in history, it has not been replaced by newer valves such as ball valves, but its market presence has become increasingly popular.

There are two basic series of plug valves:

1. X43F type: This type features a sealing pair composed of a specially designed valve seat bushing (PTFE or para polyphenylene) and a steel plug body. The plug body is made of stainless steel (not lined).

2. X43F46 type: This type has FEP lining on the surface of all valve bodies and plug passages, as well as linings of PFA, PCTFE, and PPL, which can withstand temperatures up to 300℃. These new materials are used for inlaying the valve seat to meet various working conditions. The X43F and X43F46 self-lubricating plug valves have a unique rocker arm adjusting device and an ideal plug cone angle design, offering good sealing performance, a long service life, and the advantage of simultaneous sealing at both the inlet and outlet ends. Throughout the entire working process, the friction coefficient of the sealing pair is low, and the plug body operates flexibly without the need for lubrication.

Structural Features of the X43F Plug Valve

1. The inlet and outlet windows of the valve body are designed with a double groove seal ring structure. During the rotation of the plug, the sealing specific pressure between its seal pairs gradually changes until it reaches the fully open or fully closed position, generating sufficient sealing specific pressure and achieving zero leakage of the seal pair.

2. The double groove seal ring not only allows the PTFE bushing to displace stably within the valve body but also absorbs slight deformation of the bushing caused by temperature changes. Additionally, the bushing and the plug provide a strong wiping effect, which improves the service life of the sealing surface.

3. The upper part of the plug shaft consists of a PTFE diaphragm, an O-ring, and an adjusting gasket. This assembly can adjust the sealing specific pressure between the sealing surfaces, allowing the plug to rotate flexibly while ensuring the sealing of the inlet and outlet ends, as well as the connecting end of the middle flange.

4. The entire sealing process can be considered approximately independent of the pressure in the pipeline.

5. The PTFE bushing is filled with different materials according to the service temperature and working medium, providing good lubrication and a long service life.