Plug Valve

Table of Contents

What is a Plug Valve?

A plug valve is a type of valve that uses a cylindrical or tapered plug that can be rotated inside the pipe to control flow [1]. Plug valves have a passage that, depending on how the valve is oriented, allow flow across the pipe. When the valve is open, the passage is in line with the pipe openings, allowing full flow [1]. When the plug is turned 90 degrees, the passage is perpendicular to the pipe openings, and the fluid is stopped by the solid part of the valve, that is, the valve is closed. There are two types of plug valves: lubricated and non-lubricated.

Multiport Plug Valve 

There are many plug valves with two, three, or even four ports. Multiport plug valves are used to direct and divert flow to specific lines, as well as blocking the flow, whereas single port valves can only block flow. There are also multiport valves that do not stop the flow, and can only redirect it [1].

Plug Valve Components

A plug valve generally consists of a body, stem, disk, and bonnet. The body houses the inner components of the valve and connects the pipes. The valve stem connects the valve actuator and disk, allowing the disk to be rotated by moving the actuator. The disk is the plug of the valve that allows for the control of flow and is often tapered. The plug valve disk can have many patterns [2].

Plug Valve Port Patterns

There are different types of plug valve port patterns for different applications: round, rectangular, standard, diamond, multiport, and Venturi design patterns [2]:

Rectangular port patterns are the most common port pattern type and the port opening makes up at least 70% of the pipe's cross-sectional area [1]. Round port patterns come in two types: full bore and reduced bore [1]. Reduced bore round ports are used when flow restriction is not required [1]. Diamond port plug valves are used for throttling flow [1].

Applications 

• Commonly used in low temperature and pressure applications [3]
• Some plug valves are used in high temperature and pressure applications
• Useful in applications that require control of flow direction
• Can be used in moderate vacuum environments
• Can be used in gas and liquid fuel applications
• Can be used in applications with high temperature flow
• Useful in regulating the flow of suspension mixtures such as slurries

Suppliers

Listed below are links to some common plug valve suppliers:

• Fastenal
• Flomatic
• Flowserve
• Grainger Canada
• Valmatic

References