Plug Valve: Application, Design, Buying Guide & More

Plug valves have a cylindrical or conical plug that can be rotated 90 degrees. The passageway of cylindrical valve plugs is generally rectangular, while the passageway of conical valve plugs is trapezoidal. This makes the structure of the plug valve lighter, but it also creates a certain flow loss. A plug valve is ideal for use as a cut-off and connection medium and bypass valve. Although it can sometimes be used for throttling, depending on the nature of the application and the erosion resistance of the sealing surface.

1. Definition of Plug Valve

Plug valves are quick-opening straight-through valves. Because the movement between the sealing surfaces acts as a wiping action, and it can completely eliminate contact with flowing medium when fully opened, it can also be used for medium with floating particles. Plug valves can also be designed in a multi-port pipeline. One valve can be designed in two, three, or even four ports. It will simplify the design of the piping system and reduce the number of valves and connections required.

2. Plug Valve Working Principles

As a component for the opening and closing, use a plug with a through-hole. The plug rotates with the stem to achieve opening and closing. Plug valves are mostly cones (also cylinders), which combine with the cone hole surface on the valve body to seal. Plug valves were the earliest valves used, featuring a simple structure, fast switching, and low fluid resistance. Plug valves normally seal by direct contact between the machined metal plug and the valve body, so the sealing is poor, the opening and closing force is large, and it is easy to wear.

3. Plug Valve Design Standard

4. Advantages of Plug Valve

• For frequent operations, rapid and light opening and closing
• Small flow resistance
• Simple design, small size, lightweight and easy to maintain
• Tight sealed
• with no restriction on flow direction
• low vibration and low noise

5. Application of plug valve

Plug valves are widely used in oilfield, gas field mining, transportation, and refining equipment, as well as in the petrochemical industries, chemical industries, coal gas, natural gas, liquefied petroleum gas, and HVAC industries, and general industries.

6. Selection Guide of Plug Valve

Plug valves can be selected in accordance with the following principles based on their structure and function

• When distributing the medium and changing the flow direction, its working temperature is not greater than 300°C, its nominal pressure is PN*1.6MPa, and its nominal diameter is not more than 300mm, Plug valves with multiple channels are recommended.

• The equipment and pipelines of food processing plants, such as those that produce milk, juice, beer, and pharmaceutical products, should be fitted with austenitic stainless steel, and tight-type conical plug valves.

• Nominal pressure levels and nominal diameters are not greater than 300mm and Class300 for oil field mining, natural gas field mining, oil and gas transportation pipeline, refining, and cleaning equipment. Oil-sealed conical plug valves are recommended.

• For oil field mining, gas mining, pipeline transportation branch pipes, refining, and cleaning equipment, the nominal pressure level must not exceed Class1500, the nominal diameter must not exceed 900mm, and the operating temperature must not exceed 340°C. Oil-sealed conical plug valves are recommended.

• Pipelines and equipment that contain corrosive media need to open or close quickly in the chemical industry. For nitric acid, a Teflon sleeve seal conical plug valve can be used; for acetic acid, stainless steel inlaid PTFE sleeve sealed conical plug valve can be selected.

• For the pipeline neutralization equipment of gas, natural gas, and HVAC systems, the nominal diameter should not exceed 200nm, and the gland packing conical plug valve should be used.

Aira Euro Automation is a leading Pneumatic Plug Valve Manufacturer and Supplier in India. Aira has a wide range of plug valves such as 2 Way, 3 Way Jacketed, 150# & 300#.