Sleeved Plug Valve consists of a cavity in the middle of plug along its axis. This cavity is closed at the bottom and fitted with a sealant-injection fitting at the top. The sealant is injected into the cavity, and a check valve below the injection fitting prevents the sealant from flowing in the reverse direction. The sealant oozes out from the center cavity through radial holes into lubricant grooves that extend along the length of the seating surface of the plug.

In order to reduce the torque of conventional metal seat lubricated plug valves, Sleeved Plug Valve are invented and widely used. In addition to the characteristics of conventional oil ubricated plug valves, the pressure balanced plug valves also have the following characteristics:

• 1.The plug cone of the pressure balanced lubricated plug valve is mounted in an inverted position. There is a check valve on the upper part of the plug cone. When the valve is closed, due to the difference in the upper and lower cut area of the plug cone, the injected high-pressure sealing oil causes the plug body to be lifted upwardly, so that the plug body and the valve sealing surface can be better sealed.