A plug valve is one of the most common valve designs employed today (other common types being the butterfly, gate, globe and ball valves). The plug valve has a simple design, few parts and is easy to maintain. Like the gate valve, it is not well suited for throttling applications, but is well suited for on-off operation.
Plug valves are rotary motion valves (as are ball and butterfly valves).
The plug valve is named after the type of disc employed, this is also true for gate and ball valves.
The plug valve consists of a disc, stem, body, actuator, bonnet and packing.
The bonnet can be removed in order that the valves internal parts (trim) can be accessed for maintenance and inspection.
The type of disc employed is one of three designs; rectangular, round and diamond. Rectangular design plug valves are the most common with diamond type designs being used mostly for throttling applications only.
Plug valves are either lubricated or non-lubricated depending upon design. Both designs ensure that the amount of torque required to actuate the valve is as low as possible.
How Plug Valves Work
The below video is an extract from our Introduction to Valves Online Video Course.
The greatest advantage with plug valves is that they can be used for multi-port applications, where flow can be diverted in several directions and the flow direction can be changed quickly. This multi-port setup is useful for diverting flow and reduces the total number of valves required within a piping system.
Plug valves are also fast acting and have a low pressure drop.
3D Model Components
This 3D model contains all common parts of a plug valve, these include: