Plug valve is a kind of fast on-off through conduit valve, the friction caused by the movement between the sealing surface under the condition of fully-open can completely prevent the contact with the flowing medium, therefore it can usually be used for a wide range of flow control and isolation applications including clean and dirty water, sewage, sludge and slurries, air and other services. Plug valve is characterized by its long service life and high reliability, which is a good choice for many corrosive, abrasive, toxic, continuous operation and other media and devices, widely used in the chemical industry.

According to its structure, the plug valve can be divided into fixed plug valve, self-sealing plug valve and oil filling plug valve. According to the ports form, it also can be divided into through conduit plug valve, three-way plug valve or four-way plug valve and sleeve plug valve.