Wafer Butterfly Valve SS316 | PTFE Coated SS316 Disc | Greater Chemical Resistance
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SS316 Wafer Butterfly Valve — PTFE Coated Disc and PTFE Seat for Maximum Chemical Protection
This SS316 wafer butterfly valve takes chemical protection a step further than the standard SS316 disc version: the disc features a PTFE coating over its entire surface, completely eliminating contact between the disc's metal and the process fluid. In the open position, the disc is the only component remaining within the flow — with PTFE coating, no metallic part is exposed to the fluid, regardless of the level of chemical aggressiveness.
The combination of an SS316 body, PTFE-coated SS316 disc, and PTFE seat makes this valve the right choice when the fluid is aggressive enough to attack the SS316 of the disc in continuous service, but does not require the level of protection of an anti-corrosion valve with a full PFA liner.
Construction Materials
- Body: CF8M Stainless Steel (cast equivalent of SS316)
- Disc: SS316 Stainless Steel with full-surface PTFE coating — no metal-fluid contact in any open position
- Seat: PTFE — seals circumferentially with the coated disc upon closing
- Shaft / Stem: SS316 Stainless Steel with PTFE seals
Technical Specifications
- Mounting Type: Wafer — between DIN PN10/16 or ANSI 150 flanges
- Nominal Pressure: PN10 / PN16
- Operating Temperature: -20 °C to +150 °C
- Available Diameters: DN50 (2") to DN600 (24")
- Design Standard: EN 593
- Actuator Interface: ISO 5211
When to Specify a PTFE Coated Disc Instead of a Standard SS316 Disc?
The uncoated SS316 disc resists corrosion from most aqueous fluids. The PTFE coated disc is the right choice when:
- The fluid contains chloride concentrations that would cause pitting in the SS316 disc over time (seawater at elevated temperatures, concentrated brines)
- The fluid is a moderately-high concentration acid where SS316 would show generalized corrosion with prolonged contact
- Zero metallic contamination of the fluid is required — the PTFE coating ensures that no metallic ions from the disc contaminate the process
- The fluid is a moderate oxidant that would attack the SS316 disc in continuous open and close cycles
Comparison of the Three SS316 Butterfly Valve Variants
| Variant | Disc | Seat | Best for |
|---|---|---|---|
| SS316 + EPDM | Uncoated SS316 | EPDM | Water, HVAC, general services |
| SS316 + Standard PTFE Disc | Uncoated SS316 | PTFE | Diluted acids and alkalis, higher temperature |
| SS316 + Coated PTFE Disc ← This Product | PTFE Coated SS316 | PTFE | Fluids that attack SS316 disc — high chlorides, moderate acids, zero metallic contamination |
Compatible Fluids
- ✅ Sulfuric acid H₂SO₄ up to 40%
- ✅ Hydrochloric acid HCl up to 30%
- ✅ Nitric acid HNO₃ up to 30%
- ✅ Seawater and concentrated brines
- ✅ Sodium hypochlorite NaClO up to 15%
- ✅ Ferric chloride FeCl₃ — any concentration
- ✅ NaOH up to 40%
- ✅ Purified and demineralized water without metallic contamination
- ✅ Water treatment solutions with moderate oxidizers
- ⚠️ For HF, H₂SO₄ >70%, concentrated ClO₂: use PFA anti-corrosion valve →
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 modulating 4–20 mA.
For the complete range of SS316 butterfly valves, see stainless steel butterfly valves category →