Plug valves are valves with cylindrical or conically tapered "plugs" which can be rotated within the valve body to govern drift through the valve. The plugs in plug valves have one or greater hole passageways going sideways thru the plug, in order that fluid can drift through the plug while the valve is open. Plug valves are simple and often most economical.

When the plug is conically tapered, the stem/handle is usually connected to the larger diameter give up of the plug. Plug valves usually do not have bonnets however frequently have the cease of the plug with the deal exposed or by and large uncovered to the outside. In such cases, there may generally not be lots of a stem. The stem and deal with frequently are available one piece, often an easy, approximately L-formed manager connected to the quit of the plug. The other end of the plug is frequently uncovered to the out of doors of the valve too, however with a mechanism that keeps the plug inside the body.

The simplest and most common well known kind of plug valve oil and gas industry in India with positions: open to permit flow, and shut (closed) to prevent going with the flow. Ports are openings inside the valve body through which fluid can input or depart. The plug on this form of valve has one passageway going through it. The ports are commonly at opposite ends of the body; consequently, the plug is rotated a fourth of a full turn to change from open to shut positions. This makes this type of plug valve 1 / 4-turn valve. There is mostly a mechanism prescribing motion to take care of a quarter flip, but no longer in glass stopcocks.

Slightly conically tapered steel (often brass) plug valves are often used as simple shut-off valves in household natural gas traces.

It is likewise possible for a plug valve to have greater than ports. In a 3-manner plug valve, glide from one port might be directed to either the second one or 0.33 port. A three-manner plug valve may also be designed to shift waft between ports 1 and 2, 2 and 3, or 1 and 3, and in all likelihood even join all three ports together. The go with the flow-directing possibilities in multi-port plug valves are just like the opportunities in corresponding multi-port ball valves or corresponding multi-port valves with a rotor. An additional possibility in plug valves is to have one port on one facet of the plug valve and ports on the opposite facet, with two diagonal and parallel fluid pathways inside the plug. In this example the plug can be circled a hundred and eighty° to connect the port on the only aspect to either of the 2 ports on the opposite aspect.