Plug valves are quarter turn operated and can be Lubricated or Non-Lubricated.
Lubricant is injected under pressure between the plug face and body seat to reduce friction, provides port sealing and allows sealant jacking action to unseat the plug-in tapered designs.
The Non-lubricated type shows mechanical design characteristics capable to reduce friction between the plug face and body seat during operation by lifting the plug or, in the split-body type valve, by lifting the shutter from the seat before the rotation. Alternatively, PTFE linings or sleeves are used. Both types are available in parallel and tapered versions.
Sleeved Plug valves are usually of tapered design and incorporates a polymeric sleeve in the body, usually in PTFE.