Stockist & supplier ASME B16.21 · EN 1514-1
PTFE Gaskets — Virgin, Filled, Expanded & Envelope
PTFE gaskets are flat gaskets made from polytetrafluoroethylene, which resists almost all chemicals. Teshi Group stocks and supplies virgin, filled, expanded (ePTFE) and envelope PTFE gaskets to ASME B16.21 and EN 1514-1 dimensions.
Also called: Teflon gasket, virgin PTFE gasket, filled PTFE gasket, expanded PTFE gasket, ePTFE gasket, PTFE envelope gasket
What is a PTFE Gasket?
PTFE is chemically inert across nearly the full pH range and does not contaminate the process fluid. Virgin PTFE tends to creep (cold flow) under bolt load, so filled grades with glass, silica, barium sulphate or graphite, and expanded PTFE with a fibrous structure, are used to improve creep resistance. Envelope gaskets wrap a PTFE jacket around a CNAF or rubber insert, combining chemical resistance on the wetted face with resilience. PTFE gaskets suit acid, alkali, solvent, food and pharmaceutical lines, including glass-lined and plastic flanges.
Key features
- Virgin and filled PTFE (glass, silica, barium sulphate, graphite)
- Expanded PTFE (ePTFE) sheet and joint sealant tape
- PTFE envelope gaskets with CNAF or rubber insert
- Ring and full-face to ASME B16.21 and EN 1514-1; cut to drawing
- Thickness 1.5 mm and 3 mm standard
Specification
| Supply | Stockist & supplier — Teshi Group, India |
|---|---|
| Standard | ASME B16.21 (dimensions), EN 1514-1 (PN flanges) |
| Types | Virgin PTFE, filled PTFE, expanded PTFE, envelope |
| Fillers | Glass, silica, barium sulphate, graphite / carbon |
| Thickness | 1.5 mm (1/16"), 3 mm (1/8"); others on request |
| Service | Commonly cited range about −200 °C to +260 °C, subject to grade and pressure |
| Documents | Manufacturer's test certificate, dimensional inspection report |
Applications
- Acid and alkali lines
- Solvent and chemical transfer
- Food, beverage and pharmaceutical piping
- Glass-lined and plastic-lined flanges
- Chlorine and caustic service
FAQ
PTFE Gasket: common questions
Why not use virgin PTFE for all chemical service?
Virgin PTFE creeps under bolt load and loses seal stress, especially with heat. Filled or expanded PTFE resists creep much better and is preferred on most flanges.
What is an envelope gasket?
It is a PTFE jacket around a softer insert such as CNAF or rubber. The PTFE contacts the fluid while the insert gives resilience, suiting glass-lined and fragile flanges.
Is PTFE gasket the same as Teflon gasket?
Yes. Teflon is a brand name for PTFE, and buyers often use the two terms interchangeably. Specify the PTFE type, such as virgin, filled or expanded, rather than the brand name.
Which PTFE gasket suits glass-lined flanges?
PTFE envelope gaskets or soft expanded PTFE are used on glass-lined and plastic flanges, because they seal at low bolt load and do not overstress the fragile flange face.
Need a size or grade not listed here?
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- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
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