PTFE Rods for Valve Seats & Seals
How PTFE rod is machined into valve seats, seal rings and back-up rings for aggressive service.
Why PTFE for valve seats and seals
Valve seats and seals machined from PTFE rod hold a tight shut-off against media that would attack elastomer or metal seats. PTFE's chemical inertness means the seat does not degrade in acids, caustics, chlorine or solvents, and its wide temperature range (-180°C to +260°C) covers everything from cryogenic to steam service. The low friction gives smooth valve operation and low breakaway torque, and because PTFE is soft it conforms slightly to the sealing face, achieving a bubble-tight seal even on a lightly imperfect surface.
Back-up rings and anti-extrusion
In high-pressure hydraulic and oil-and-gas seals, PTFE rod is machined into back-up rings that sit behind an elastomer O-ring to stop it extruding into the gap under pressure. The PTFE ring takes the extrusion load while the elastomer does the sealing. For these dynamic, high-pressure duties, filled PTFE (glass or carbon) is usually specified over virgin PTFE for its higher resistance to creep and extrusion.
Specifying a machined seal
Because PTFE cold-flows under sustained clamp load, seal and seat designs must confine the PTFE in a groove or gland rather than relying on it to hold shape unsupported. Give us the valve or gland dimensions, the media, the temperature and the pressure, and we will confirm whether virgin or filled PTFE rod is the right machining stock and the correct oversize allowance for finishing.
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Tell us the part, the media and the temperature, and we'll confirm the right PTFE grade to machine from.