Plug valve
A plug valve rotates a ported or contoured plug inside the body to align the passage with the pipeline or block it. Operation is commonly quarter-turn, but port geometry, lubrication, and sealing arrangements differ across designs. Unlike a ball valve, its rotating closure member is a plug whose seating relationship with the body defines the flow path and seal. Selection should address port pattern, operating torque, sealing method, lubrication requirements, flow direction, and whether the duty is isolation or flow diversion.
Application and duty
Isolation or flow-diversion duty suited to a rotating plug mechanism; port arrangement and sealing system must match the required service.