Plug Valves

A plug valve is a quarter-turn valve with a tapered or cylindrical plug carrying a port through its body. A ninety degree turn aligns the port with the pipe or turns it across the flow to close. The plug presents a smooth, flush passage that resists fouling and is easy to clean, which makes plug valves a good choice for media that would damage the softer seats of a valve built for clean-water duty, such as slurries, sewage, viscous fluids and chemical effluent.

In a lubricated plug valve a sealant film reduces friction and helps seal, suiting higher pressure and gas service. In a non-lubricated design the plug runs in a polymer sleeve or lining (often PTFE) that provides the seal without maintenance. The eccentric plug valve uses an off-centre plug that lifts clear of the seat on opening and seats with positive mechanical pressure on closing, so the plug does not drag across the seat face. This greatly reduces seat wear and gives long life under frequent operation.

Multi-port plug valves route flow between several connections in a single body. A three-way plug valve diverts flow between two outlets or mixes two inlets, replacing several two-way valves in dosing systems, bypass arrangements and manifolds. Applications range across water and wastewater, chemical process, hydrocarbons and industrial services where reliable isolation or diversion of a demanding medium is needed.

Bodies are made in ductile and cast iron, cast steel and stainless steel, plain or PTFE-lined for chemical duty, with flanged connections to EN 1092 or ASME B16.5 and testing to EN 12266 or API 598. Relevant standards include API 599 for steel plug valves. When specifying, provide the bore, pressure rating, medium, the seating type (lubricated, sleeved or eccentric), the number of ports and the actuation, and we can propose a suitable valve.