The use of a cylindrical plug valve depends, to some extent, on the seal created between the plug and the valve body. Common cylindrical plug valves are often used four sealing methods, the use of sealant, the use of expansion valve, the use of 0-ring, the use of eccentric plug wedge valve seat ring. Cylindrical lubrication plug valve seal by the sealing agent between the valve plug and body to achieve. Sealant is bolted or injection gun through the valve rod into the sealing surface, so when the valve is in use, you can by injection of supplementary sealant to effectively compensate for its lack of sealing. Lubricated plug valves are particularly suitable for abrasive media because the seal faces are protected from contact with the flow media while in the fully open position. However, lubricated plug valves should not be used for throttling, which is due to throttling from the exposed sealing surface flush sealant, so that each time the valve is closed, the valve seat seal to be restored. The disadvantage of this valve is that the addition of sealants is often done manually, although autoinjection overcomes this disadvantage, but increases the cost of retrofitting equipment. Once the valve has to be cleaned or repaired at this time, due to lack of maintenance, improper sealant selection, or crystallization between the sealing surfaces and the fact that the valve plug can not rotate in the valve body. Cylindrical plug valve, the body is equipped with a PTFE sleeve and the plug seal, which is pressed with a compression nut in the valve body, by the plug on the PTFE sleeve expansion force to seal .