What is Plug Valve?

Plug valve is the valve that uses a tapered or cylindrical “plug” to stop or start the flow. The plug in the plug valve has a hollow passage to pass the fluid. When the valve is open, this bored passage is in line with the flow. When the plug is rotated a quarter turn to change from open to closed positions, the solid part of the plug stops the flow.
 

Plug valve is used in place of gate valve if a quick operation is required. It can be used in high-pressure and high temperature services.

Plug Valve Parts

Typical plug valve consists of body, bonnet, stem and plug. For lubricated plug valve, the seat is an integral part of the body. For non-lubricated plug valve, a non-metallic seat is used to improve leak tightness of the valve.
 

Plugs are either cylindrical or conically tapered. And they may have various types of ports (openings in the valve body where the flow can enter or leave), each with a varying degree of the opening area.

Plugs



Rectangular port plug is the most common port shape for plug valve. The rectangular port represents at least 70% of the cross-sectional area of the corresponding pipe.

Diamond port plug has a diamond-shaped port through the plug. The port is Venturi restricted flow type. The design is well suited for throttling service.

Round port plug has a round port through the plug. If the diameter of the port is the same as or larger than the inside diameter of the pipe, this is a full port, also called full bore. If the diameter of the port is smaller than the inside diameter of the pipe, this is a standard round port.

Plug Valve Application