Butterfly Valves for Water, Gas and Chemical Applications
Butterfly Valves for Water, Gas and Chemical Applications: Media Compatibility Guide
Different media demand different materials. A valve that works for chilled water may fail quickly on chemical or gas lines. This guide provides direct selection tables for water, gas, and chemical applications.
Quick Selection Matrix by Media
| Media Category | Recommended Body | Recommended Disc | Recommended Seat |
|---|---|---|---|
| Fresh / Chilled Water | Ductile Iron | Epoxy-coated DI | EPDM |
| Sea / Brackish Water | Ductile Iron / SS316 | SS316 | EPDM / Viton |
| Hot Water (80-120°C) | Ductile Iron | SS304 | EPDM |
| Low Pressure Steam | Cast Steel | SS304 | PTFE / Graphite |
| Natural Gas / LPG | Ductile Iron | SS304 / Aluminum Bronze | NBR / Viton |
| Compressed Air | Ductile Iron | Epoxy-coated DI | NBR |
| Mild Acids (pH 3-6) | SS316 | SS316 | Viton / PTFE |
| Strong Acids (pH <3) | PTFE-lined | PTFE-coated | PTFE |
| Caustics / Alkalis | SS316 / Ductile Iron | SS316 | EPDM / Viton |
| Solvents | SS316 | SS316 | Viton / PTFE |
| Oils / Hydrocarbons | Cast Iron / Steel | SS304 | NBR / Viton |
Water Applications
| Water Type | Key Challenge | Recommended Seat | Recommended Disc |
|---|---|---|---|
| Potable Water | NSF certification | EPDM (NSF) | Epoxy-coated |
| Chilled Water | Low temperature | EPDM | Epoxy-coated |
| Cooling Tower | Aeration, biological growth | EPDM / Viton | SS304+ |
| Sea Water | Chloride corrosion | EPDM | SS316 (CF8M) |
| Wastewater | Abrasive solids | EPDM | Epoxy-coated + SS edge |
Gas Applications
| Gas Type | Key Safety Concern | Recommended Seat | Disc Material |
|---|---|---|---|
| Natural Gas | Flammability | NBR / Viton | SS304 |
| LPG / Propane | High pressure | NBR | SS304 |
| Compressed Air | Pressure spikes | NBR | Epoxy-coated DI |
| Oxygen | Combustion hazard | PTFE (degreased) | SS316 |
| Biogas | Corrosive H2S | Viton | SS316 |
Warning for Oxygen Service: Use only degreased, oil-free valves with PTFE seats. Standard valves will ignite.
Chemical Compatibility – Seat Materials
| Seat Material | Water | Steam | Acids | Caustics | Solvents | Oils | Gas |
|---|---|---|---|---|---|---|---|
| EPDM | A | C | D | A | D | D | B |
| NBR | A | D | D | C | C | A | A |
| Viton | A | B | B | D | B | A | A |
| PTFE | A | A | A | A | A | A | A |
Rating: A=Excellent / B=Good / C=Fair / D=Poor (Do not use)
End Connection by Application
| Media | Wafer | Lug | Flanged |
|---|---|---|---|
| Water (closed loop) | Yes | Optional | No |
| Water (dead-end) | No | Yes | Yes |
| Gas | Yes | Optional | Rare |
| Chemical | No (lined unavailable) | No | Yes |
Common Mistakes to Avoid
| Mistake | Consequence | Correct Practice |
|---|---|---|
| EPDM seat with solvents | Seat swells, valve locks | Use Viton or PTFE |
| SS304 disc in seawater | Pitting corrosion | Use SS316 |
| Wafer valve at dead-end line | Disc damage, leakage | Use lug or flanged |
| No grounding for natural gas | Static spark risk | Install anti-static device |
Summary Selection Checklist
Before specifying, confirm:
-
Media – exact fluid and concentration
-
Temperature – min, max, peak
-
Pressure – operating and shut-off
-
End connection – wafer, lug, or flanged
Contact our team for verified compatibility recommendations.
Ivan (Mobile:+86-18968769287)
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Wechat:+86-18968769287
Website：www.kinko-flow.com
ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD
