Plug Valves

Plug Valves by John Valves

These quarter-turn rotary motion valves use a tapered or cylindrical plug-shaped disc to stop or start flow. Plug valves allow for flow in either direction in a fully open or closed position. They are ideal on-off or redirect valves with moderate throttling capability.

Plug valves are used primarily as a shut-off valve in bubble-tight services. These include air, gas, vapour and liquid services, for example.

We locally manufacture and supply a range of plug valves including:

  • John Fig. 201, 2-Way Lubricated Plug Valve
  • John Fig. 301, 3-Way ‘T’ and ‘L’ Port Lubricated Plug Valve

Frequently Asked Questions About Plug Valves

Got questions? Below are some of the questions we get asked often about plug valves.

Plug valves are used in many different fluid services. The plug does not permit accumulation of suspended particles because of its wiping off-action. This makes it ideal for slurry applications. They are commonly found in the following services and applications:

  • Air, gaseous and vapour services
  • Natural gas and oil piping systems
  • Slurries and wastewater applications
  • Vacuum to high-pressure applications

The ball valve and plug valve have many similarities in terms of how they function and their application. They are both used for providing drop tight shut-offs in different piping systems. They do, however, have a few key differences.

Where we see a spherical disc with a hollow centre in a ball valve, a plug valve consists of a conical disc that has bored passages running through it. The plug in a plug valve is larger than the ball in a ball valve. This means that the plug valve provides a tighter shut off in comparison.

Control valves need regular and ongoing maintenance. In comparison to a ball valve, a plug valve is easier to maintain. This is because the plug is easily removable thus allowing easy access to the valve body. In essence, plug valves have a simpler construction which has benefits when it comes to maintenance and repairs.