Wafer Butterfly Valve Seat and Disc SS304 + Teflon
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Wafer Butterfly Valve — WCB Body, PTFE Coated SS304 Disc and PTFE Coated EPDM Seat
This wafer butterfly valve is the most chemically protected variant within the WCB family with an EPDM/PTFE seat. Both the seat and the disc are PTFE coated — the fluid does not come into contact with any metallic surface in any open or closed position. The WCB body is protected by the EPDM/PTFE seat, and the SS304 disc is protected by its PTFE coating over its entire surface exposed to the fluid in the open position.
Compared to the variant with an uncoated SS304 disc, this product is the correct choice when the fluid is aggressive enough to attack the SS304 of the disc in continuous service — fluids with moderate-to-high chlorides, mild oxidizers, or acids in concentrations that would damage 304 stainless steel over time — without needing the higher cost of an SS316L body.
Construction Materials
- Body: Carbon steel WCB — mechanical support structure with no fluid contact
- Disc: SS304 Stainless steel with PTFE coating over its entire surface — the disc metal has no contact with the fluid in any position
- Seat: PTFE coated EPDM — elastomeric core for resilience and sealing + outer PTFE layer in contact with the fluid
- Shaft / Stem: SS316 Stainless steel with PTFE retainers
Technical Specifications
- Mounting Type: Wafer — between DIN PN10/16 or ANSI 150 flanges
- Nominal Pressure: PN16
- Operating Temperature: -20 °C to +130 °C (limited by the EPDM core of the seat)
- Available Diameters: DN50 (2") to DN600 (24")
- Design Standard: EN 593
- Actuator Interface: ISO 5211
Compatible Fluids
- ✅ Water with moderate chlorides up to 1,000 ppm — the PTFE coating protects the SS304 disc
- ✅ Sulfuric acid H₂SO₄ up to 25%
- ✅ Hydrochloric acid HCl up to 20%
- ✅ Nitric acid HNO₃ up to 25%
- ✅ Acetic acid up to 60%
- ✅ NaOH up to 30%
- ✅ Sodium hypochlorite NaClO up to 12%
- ✅ Wastewater with moderate chemical content
- ✅ Fluids where contamination by metallic ions from the disc is unacceptable
- ⚠️ Maximum temperature 130 °C — the EPDM core limits the temperature despite the PTFE coating on the disc
- ⚠️ Oils and fuels: PTFE is compatible but the EPDM core may be affected — use NBR or Viton seat
- ⚠️ HF, H₂SO₄ >70%, concentrated ClO₂: use PFA anti-corrosive valve →
Full Comparison — WCB family with PTFE coated EPDM seat
| Variant | Disc | Metal-Fluid Contact | Relative Cost | Best for |
|---|---|---|---|---|
| WCB + SS304 + EPDM/PTFE | Uncoated SS304 | ⚠️ SS304 Disc exposed in open position | ✅ Lower | Moderate chemistry without high chlorides — SS304 disc sufficient |
| WCB + PTFE Coated SS304 + EPDM/PTFE ← This | PTFE Coated SS304 | ✅ Zero — only PTFE touches the fluid | Medium | Fluids that attack SS304 disc — moderate chlorides, mild oxidizers, zero metallic contamination |
Available Operation Versions
- Manual with lever: DN50 to DN200
- Manual with gear reducer: DN200 to DN600
- With pneumatic actuator: Single acting NC or NO, double acting. ISO 5211 + NAMUR.
- With electric actuator: 24 VDC, 110 VAC, 220 VAC. ON/OFF or 4–20 mA modulating.
For the complete range of anti-corrosive valves, see anti-corrosive butterfly valve category →