PTFE Envelope Gaskets — Slit, Machined & Folded Types
Technical Specification
| Envelope Material: | Virgin PTFE |
|---|---|
| Envelope Types: | Slit (cut), machined and folded envelopes |
| Insert Materials: | Non-asbestos (CNAF) sheet, rubber, or as specified |
| Standards: | ASME B16.21 / B16.5, EN 1514 / EN 1092-1, or to drawing |
| Service Temperature: | Depends on insert material; confirm for your service |
| Note: | Figures are typical; confirm exact grade, size and rating with our team |
Why PTFE Envelope Gaskets?
- Chemical resistance: only PTFE touches the process fluid
- Low bolt load: the soft insert seals fragile glass-lined and plastic flanges
- Better recovery: the insert gives resilience that solid PTFE lacks
- Cost-effective: less PTFE than a solid gasket of the same size
Envelope Types
- Slit type: PTFE cut and opened to take the insert; economical for standard sizes
- Machined type: envelope machined from PTFE for precise, larger or thicker gaskets
- Folded type: PTFE film folded around the insert for large diameters
Information to Send
- Flange standard, size and pressure class, or a drawing
- Envelope type and insert material
- Process fluid, temperature and pressure
- Quantity
See also: PTFE (Teflon) Gaskets, Non-Asbestos Gasket Sheet (CNAF), PTFE Gasket Guide and PTFE (Teflon) Products.
Send us your drawing or sizes, the grade, quantity and service conditions, and our Al Khobar team will confirm availability, lead time and a quotation for delivery anywhere in Saudi Arabia and the GCC. Every order is supplied with a Material Test Certificate.
Frequently Asked Questions
Q1. What is a PTFE envelope gasket?
A. A gasket with a PTFE jacket over a compressible insert, so only PTFE contacts the fluid while the insert gives resilience.
Q2. Where are PTFE envelope gaskets used?
A. On glass-lined, FRP, plastic and other fragile or chemical-service flanges.
Q3. What insert is used inside the envelope?
A. Usually non-asbestos (CNAF) sheet or rubber, chosen to suit temperature and pressure.
Q4. Do you supply envelope gaskets for ASME flanges?
A. Yes, and for EN flanges or to your drawing.
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