The plug valve is a closing or plunger-shaped rotary valve, rotate 90 degrees so that the passageway on the valve plug is the same as or separated from the channel opening on the valve body, to achieve the purpose of opening or closing the valve.
The plug body rotates with the stem, to achieve opening and closing action. Small, no stuffing plug valves are also called the plug valves "Cork". Most of the plug valves plug is a cone, and the valve body with the tapered hole surface to form a seal.
The plug valve is used as one of the earliest valves, its structure is simple, the switch is quick, the fluid resistance is small. Ordinary plug valves are sealed by direct contact between the finely machined metal plug and the valve body, therefore, poor sealing, opening and closing force is large, easy to wear, usually only for low (not higher than 1 MPa) and a small diameter applications (less than 100 mm).