Ready stock for immediate enquiry
2 inch (DN50) and 4 inch (DN100) Alloy 20 dual plate wafer check valves, Class 150, available now. Reserve via quote form or email info@supremevalves.in.
Alloy 20 Dual Plate Check Valve
Supreme Valves manufactures the Alloy 20 dual plate check valve (also called Alloy 20 dual disc / wafer check) in UNS N08020 / ASTM A351 CN7M for sulfuric acid, copper leach raffinate, fertilizer acid, and related chemical services. Spring-assisted dual plates give compact API 594 face-to-face and non-slam closure on pump discharge and acid transfer lines.
What buyers mean by Alloy 20 dual plate check valve
Search demand for alloy 20 dual plate check valve and alloy 20 wafer check valve comes from sulfuric acid plant engineers, mining hydrometallurgy packages, and chemical EPCs who need a short-pattern non-return valve that survives H2SO4 where SS316 fails. The dual-plate (dual disc) wafer body sits between ASME B16.5 flanges. Two spring-loaded plates open with forward flow and close on reverse flow, limiting slam and water hammer on pump stop.
Alloy 20 (also written Carpenter 20, UNS N08020, cast as CN7M) is a nickel-chromium-molybdenum-copper austenitic alloy stabilised for sulfuric acid. Supreme Valves supplies full Alloy 20 wetted construction for the dual plate check — body, plates, hinge pins, and seats — not a coated carbon-steel body.
Materials of construction
| Component | Material |
|---|---|
| Body | Alloy 20 UNS N08020 / ASTM A351 CN7M (cast) or ASTM B462 / B473 (wrought) |
| Discs / plates | Alloy 20; metal seat or stellited seating face as specified |
| Hinge pin / retainer | Alloy 20 |
| Spring | Inconel X-750 (typical) for acid service |
| Gasket | Spiral wound SS316 / Grafoil or PTFE as applicable |
Technical specifications
| Parameter | Specification |
|---|---|
| Valve type | Dual plate / dual disc wafer check valve, spring assisted, non-slam |
| Design | API 594 wafer dual-plate practice |
| Testing | API 598 shell and seat |
| Pressure class | Class 150 standard (Class 300 / 600 on order) |
| Ends | Wafer, fits ASME B16.5 Class 150 flanges; lug pattern on request |
| Size range | 2" to 24" manufactured; 2" and 4" ready stock |
| Service | Sulfuric acid, dilution lines, raffinate / pregnant leach, chemical transfer |
| Documentation | EN 10204 3.1 MTC; PMI on request; hydro test report |
Ready stock — 2 inch and 4 inch
Alloy 20 dual plate wafer check valves are available now in 2 inch (DN50) and 4 inch (DN100), Class 150. Other sizes and Class 300 / 600 are manufactured to order. Price on enquiry — send size, quantity, flange standard, and media for a firm offer.
Alloy 20 dual plate check valve 2 inch (DN50)
The 2 inch Alloy 20 dual plate check valve is the common size on sulfuric acid dosing skids, small pump discharge, and branch acid transfer. Wafer body fits between ASME B16.5 Class 150 flanges. Full Alloy 20 (CN7M / N08020) wetted parts with spring-assisted dual plates for non-slam closure. Ready stock Class 150 wafer pattern.
Buyers searching alloy 20 wafer check valve 2 inch or CN7M dual plate check DN50 use this size for compact face-to-face where a swing check would be too long.
Alloy 20 dual plate check valve 4 inch (DN100)
The 4 inch Alloy 20 dual plate check valve suits main acid transfer and raffinate / PLS headers in copper hydrometallurgy and fertilizer acid loops. Class 150 wafer dual-plate design per API 594 practice, API 598 tested, EN 10204 3.1 documentation. Ready stock available for immediate reservation.
Match flange drilling to ASME B16.5 Class 150. Confirm acid concentration, temperature, and flow direction on the RFQ so seat facing and spring material stay correct for the duty.
Indicative Class 150 wafer dimensions
Approximate dual-plate wafer envelope. Certified face-to-face on order drawing.
| NPS | DN | Typical F-F L (mm) | Flange fit | Stock |
|---|---|---|---|---|
| 2" | 50 | ~54 | ASME B16.5 Cl.150 | Ready |
| 3" | 80 | ~67 | ASME B16.5 Cl.150 | MTO |
| 4" | 100 | ~67 | ASME B16.5 Cl.150 | Ready |
| 6" | 150 | ~95 | ASME B16.5 Cl.150 | MTO |
| 8" | 200 | ~127 | ASME B16.5 Cl.150 | MTO |
How to enquire (RFQ checklist)
- Size (2" / 4" ready stock, or other NPS) and quantity
- Pressure class and flange standard (default Class 150 ASME B16.5)
- Media: sulfuric acid concentration, temperature, solids if any
- Seat preference: metal-to-metal or stellited facing
- Delivery location and Incoterms (ex-works India or export)
- Documents: MTC 3.1, PMI, hydro report, third-party witness if required
Email info@supremevalves.in or use the quote form. Ready-stock units are reserved on confirmed enquiry.
Typical applications
- Sulfuric acid plant pump discharge and transfer (concentrated and dilute)
- Copper and zinc hydrometallurgy — raffinate and PLS lines
- Phosphate / fertilizer acid circuits
- Specialty chemical and pharmaceutical acid handling
FAQ
Alloy 20 vs CN7M vs N08020 — same material?
Yes for valve buying. UNS N08020 is the wrought designation; CN7M is the common cast grade under ASTM A351. Buyers use Alloy 20, CN7M, and N08020 interchangeably for sulfuric acid valves.
Dual plate vs swing check in acid service?
Dual plate wafer checks are shorter and lighter and reduce slam on pump trips. Swing checks remain common on larger or horizontal lines. Spec sheet and piping layout decide; both are offered in Alloy 20.
Enquire for Alloy 20 dual plate check valve
State size, class, quantity, media, and delivery location. Ready-stock 2" and 4" are allocated on confirmed enquiry.