1. Tight-sleeve plug valve The tight-sleeved plug valve is usually used in low-pressure straight-through pipelines. The sealing performance depends entirely on the fit between the plug and the plug body. Compress the sealing surface by tightening the lower nut. Generally used for PN≤0.6MPa.
2. Packing type plug valve The packing type plug valve realizes the sealing between the plug and the plug body by compressing the packing. Due to the use of packing, the sealing performance is good. Usually this kind of plug valve has a packing gland, and there is no need to extend the valve plug out of the valve body, thereby reducing the leakage path of the working medium. This kind of plug valve is widely used in the pressure of PN≤1MPa.
3. Self-sealing plug valve The self-sealing plug valve realizes the compression seal between the plug and the plug body through the pressure of the medium itself. The small head of the plug extends upward, and the medium enters the large end of the plug through the small hole in the inlet, and the plug is pressed upward. This structure is generally used for air media.
4. In recent years, the application range of oil-sealed plug valves has been continuously expanded, and forced-lubricated oil-sealed plug valves have appeared. Due to forced lubrication, an oil film is formed between the plug and the sealing surface of the plug body. In this way, the sealing performance is better, the opening and closing is labor-saving, and the sealing surface is not damaged.