A plug valve is a closing or plunger-shaped rotary valve that is opened or closed by rotating 90 degrees so that the access port on the plug is the same or separate from the access port on the valve body. The shape of the plug valve can be cylindrical or conical. In the cylindrical valve plug, the channel is generally rectangular; In a tapered valve plug, the channel is trapezoid. These shapes make the structure of the plug valve light, but at the same time, it also produces a certain loss. Plug valves are well suited as a cut-off and closing medium and for diverting, but depending on the nature of the application and the erosion resistance of the sealing surface, they can sometimes be used for throttling. Turn the plug clockwise so that the groove is parallel to the pipe to open, and turn the plug 90 degrees counterclockwise so that the groove is perpendicular to the pipe to close.

Main categories of plug valves

A, tight plug valve

Tight plug valve is usually used for low pressure straight pipeline, sealing performance depends entirely on the fit between the plug and the plug body, the sealing surface is tightened by tightening the lower nut to achieve. Generally used for PN≤0.6Mpa.

Two, packing plug valve

The packing plug valve is sealed by pressing the packing to seal the plug and the plug body. Because of the packing, the sealing performance is better. Usually the plug valve has a packing gland, and the plug does not extend out of the body, thus reducing the leakage path of a working medium. This type of plug valve is widely used for PN≤1Mpa pressure.

Three, self-sealing plug valve

The self-sealing plug valve is tightly sealed between the plug and the plug body by the pressure of the medium itself. The small head of the plug extends upward out of the body, the medium enters the big head of the plug through the small hole at the entrance, and the plug is pressed upward. This structure is generally used for air media.

Four, oil-sealed plug valve

In recent years, the application range of plug valve has been expanding, and the oil-sealed plug valve with forced lubrication has appeared. Due to forced lubrication, an oil film is formed between the sealing surface of the plug and the plug body. This sealing performance is better, less effort to open and close, to prevent damage to the sealing surface.