The plug valve is a rotary valve in the shape of a closing member or a plunger. By rotating 90 degrees, the channel port on the valve plug is connected or separated from the channel port on the valve body to realize the opening or closing of a valve. Its valve plug can be cylindrical or conical in shape. In cylindrical valve plugs, the passages are generally rectangular; in conical valve plugs, the passages are trapezoidal. These shapes allow for a lightweight construction of the plug valve. It is best suited for shut-off and on-off media and for diverting, but may also be used for throttling depending on the nature of the application and the erosion resistance of the sealing surface. According to the structural characteristics of the plug valve and the functions that can be achieved in the design, it can be selected according to the following principles. ①It is used to distribute the medium and change the flow direction of the medium. The working temperature is not higher than 300℃, the nominal pressure PN is less than or equal to 1.6MPa, and the nominal diameter is not more than 300mm. It is recommended to use a multi-channel plug valve. ②For the equipment and pipelines of food enterprises such as milk, juice, beer, and pharmaceutical factories, it is recommended to use austenitic stainless steel, tight-fitting conical plug valves. ③In the branch pipes, refining and cleaning equipment for oil field exploitation, natural gas field exploitation, pipeline transportation, the nominal pressure level is not greater than Class300, and the nominal diameter is not greater than 300mm, it is recommended to use oil-sealed conical plug valves. ④In the branch pipes, refining and cleaning equipment of oilfield exploitation, natural gas exploitation, pipeline transportation, the nominal pressure level is not greater than Class7500, the nominal diameter is not greater than 900mm, and the working temperature is not higher than 340℃, oil-sealed conical plug valves are recommended. ⑤In the large-scale chemical industry, in the pipelines and equipment containing corrosive media, where the opening or closing speed is required to be fast, the teflon sleeve sealing conical plug valve can be selected for the nitric acid-based medium; For acetic acid-based media, Crl8Nil 2M02Ti stainless steel inlaid PTFE sleeve can be used to seal conical plug valve. ⑥ In the pipelines and equipment of gas, natural gas and HVAC systems, the nominal diameter is not greater than 200nm, and packing type conical plug valves should be used.