Ptfe Lined Butterfly Valve

butterfly valve
A valve consisting of a pair of semicircular plates that are attached to a spindle across a pipe and hinged to allow flow only one way
A butterfly valve is a valve which can be used for isolating or regulating flow. The closing mechanism takes the form of a disk. Operation is similar to that of a ball valve, which allows for quick shut off.
a valve in a carburetor that consists of a disc that turns and acts as a throttle
(Butterfly Valves) A valve consisting of a cylindrical body with a rotating vane to control flow. Tight Shutoff is obtained by an elastomer body liner into which the vane seats.
A valve consisting of a disk rotating on an axis across the diameter of a pipe to regulate the flow, as in the throttles of many engines

lined
bordered by a line of things; "tree lined streets"
(used especially of skin) marked by lines or seams; "their lined faces were immeasurably sad"; "a seamed face"
Stand or be positioned at intervals along
Mark or cover with lines
Hit a line drive
having a lining or a liner; often used in combination; "a lined skirt"; "a silk-lined jacket"

ptfe
Used as an insulator in RF and microwave coaxial connectors because of its low & stable dielectric constant and loss factor over a wide temperature and frequency range.
Polytetrafluoroethylene
In chemistry, polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE is most well known by the DuPont brand name Teflon.
Polytetrafluoroethylene is a fluoropolymer that is resistant to heat and chemicals and is used in making Teflon®. It has an extremely low coefficient of friction, and is used as a coating on cookware, gaskets, seals, and hoses.