A plug valve is a shutoff or plunger type rotary valve that opens or closes by rotating 90 degrees so that the port on the plug is the same as or separate from the port on the body. The shape of the plug can be cylindrical or conical. In cylindrical plug, the passage is generally rectangular; In the tapered plug, the passage is trapezoidal. These shapes make the structure of the plug valve lighter, but at the same time produce a certain loss. Plug valves are suitable for use as cutting and switching media and diverging applications, but are sometimes used for throttling, depending on the nature of the application and the erosion resistance of the sealing surface. Since the movement between the sealing surface of the plug valve has a wiping effect, and when fully open to prevent contact with the flow medium, it can also be used with suspended particles in the medium.