Axial Silent Check Valve
Description
TECHNICAL DATA SHEET
Axial Silent Check Valve
Ductile Iron Body · Bronze Trim
1. PRODUCT DESCRIPTION
The Axial Silent Check Valve (also referred to as axial flow non-slam check valve) is a spring-assisted, automatic non-return valve designed to prevent reverse flow and protect pumping equipment from damaging water hammer and pressure transients. Featuring a streamlined venturi-pattern flow path with an integral flow guide, this valve provides minimal pressure drop, silent operation, and rapid spring-assisted closure.
Constructed with a ductile iron body and bronze trim, this valve offers an optimal balance of corrosion resistance, strength, and cost-effectiveness for municipal water, HVAC, irrigation, and industrial pumping applications. The spring-loaded disc closes at near-zero flow velocity, ensuring positive shut-off before flow reversal occurs, thereby eliminating slamming and surge.
2. DESIGN FEATURES
| Feature | Description |
|---|---|
| Valve Type | Axial flow, spring-assisted silent check valve (non-slam) |
| Body Design | One-piece ductile iron body eliminates leak paths for superior performance |
| Flow Path | Streamlined venturi/axial design with integral straightening vanes for laminar flow and minimal head loss |
| Disc Mechanism | Center-guided, spring-loaded poppet-type disc with short stroke for rapid closure |
| Closure | Spring-assisted closure at approximately ½ psi positive head on inlet port, preventing water hammer |
| Trim Material | Bronze (aluminum bronze) – provides excellent corrosion resistance and wear properties |
| Mounting Orientation | Suitable for horizontal or vertical installation (vertical with upward flow) |
| Maintenance | Low maintenance design with durable internal components |
3. TECHNICAL SPECIFICATIONS
3.1 General Parameters
| Parameter | Specification |
|---|---|
| Size Range | DN50 – DN600 (2″ – 24″) |
| Pressure Ratings | PN10 / PN16 / Class 125 / Class 150 / Class 300 |
| Design Standards | API 594, ASME B16.34, ISO 5752 |
| Face-to-Face Dimensions | ASME B16.10, EN 558, API 609, BS 5155, DIN 3202 |
| Flange Accommodation | ASME B16.42, DIN PN10/PN16, BS 4504, ISO 7005 |
| End Connections | Wafer type, flanged (RF, FF), plain face |
3.2 Operating Conditions
| Parameter | Specification |
|---|---|
| Maximum Working Pressure | 2.5 MPa (25 bar) / Class 300 |
| Maximum Pressure (Ductile Iron) | 640 PSI @ 100°F (Class 300 WOG, non-shock) |
| Operating Temperature (Valve) | -34°C to +121°C (-30°F to 250°F) |
| Maximum Temperature (Bronze Trim) | 316°C (600°F) |
| Allowable Continuous Use Temp. | 0°C to +80°C (standard service) |
4. MATERIAL SPECIFICATION
| Component | Material | Grade / Standard |
|---|---|---|
| Body | Ductile Iron (DI) | ASTM A395 Gr. 60-40-18 / ASTM A536 |
| Disc | Bronze / Aluminum Bronze | ASTM B148 / CA377 |
| Trim | Bronze (Aluminum Bronze) | Unleaded bronze composition |
| Seat | Metal seat (Bronze) or Resilient (EPDM/NBR) | Metal-to-metal or soft-seal option |
| Spring | Stainless Steel (316 SS) | ASTM A313 Gr. CF8M |
| Guide / Bushing | Bronze / Stainless Steel | — |
| O-Ring / Seals | Buna-N (NBR) / EPDM / Viton® | Various elastomer options |
Note: Bronze trim provides excellent corrosion resistance, low friction operation, and is NSF/ANSI 61 and 372 approved for potable water applications.
5. PERFORMANCE & TESTING
| Test | Requirement |
|---|---|
| Body Shell Test | 1.5 × rated pressure (hydraulic) |
| Seat Leak Test | 1.1 × rated pressure |
| Allowable Seat Leakage | Meets or exceeds API 598 leakage requirements |
| Closure Characteristic | Silent, non-slam closure at near-zero flow velocity |
| Water Hammer Prevention | Spring-assisted disc closes before flow reversal occurs |
| Bubble-tight Seal | Available with resilient seat option |
6. DIMENSIONS (Typical – Wafer Type)
Dimensions are for reference. Consult factory for specific drawings.
| DN | Face-to-Face (mm) | Approx. Weight (kg) |
|---|---|---|
| 50 | 120 | — |
| 65 | 150 | — |
| 80 | 180 | — |
| 100 | 229 | — |
| 125 | 254 | — |
| 150 | 267 | — |
| 200 | 292 | — |
| 250 | 330 | — |
| 300 | 356 | — |
Face-to-face dimensions per GB/T 12221 / EN 558.
7. APPLICATIONS
-
Municipal water supply and distribution systems
-
Wastewater treatment plants
-
Pump discharge protection (prevents backflow and pump reversal)
-
HVAC and building services
-
Fire protection systems
-
Irrigation systems
-
Industrial process cooling water
-
Potable water systems (NSF/ANSI 61 & 372 approved with bronze trim)
8. OPTIONS & CUSTOMIZATIONS
| Option | Details |
|---|---|
| Seat Materials | Metal seat (standard), EPDM, Buna-N (NBR), Viton® (FKM), RPTFE |
| Body Materials | Ductile iron (standard), Carbon steel, Stainless Steel 316 |
| Disc Materials | Bronze, Stainless Steel 316, Ductile Iron with coating |
| Spring Materials | Stainless Steel 302, 316 |
| End Connections | Wafer, lug, flanged (RF, FF) |
| Pressure Classes | Class 125, 150, 300 |
| Coating | Epoxy coating internal/external for enhanced corrosion resistance |
9. APPLICABLE STANDARDS
| Standard | Description |
|---|---|
| API 594 | Check valves: wafer, lug, and double-flanged types |
| ASME B16.34 | Valves — Flanged, threaded, and welding end |
| ASME B16.10 | Face-to-face dimensions |
| ASME B16.42 | Ductile iron pipe flanges and flanged fittings |
| ISO 5752 | Face-to-face dimensions for valves |
| API 598 | Valve inspection and testing |
| MSS SP72 | Ball valves with flanged or butt-welding ends for general service |
| NSF/ANSI 61 & 372 | Drinking water system components – health effects & lead content |
