Automatic Recirculation Valve -- Pump Minimum Flow WCB
Integral Check Valve and Modulating Bypass for Pump Protection
Document No.SV-DS-SPC-003
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers automatic recirculation valves that combine a main line check valve with an integral modulating bypass to protect centrifugal pumps from low-flow damage in boiler feed and process applications.
Technical Specifications
| Parameter | Specification |
|---|
| Valve Size Range | DN50 to DN300 (2" to 12") main; DN25 to DN100 bypass |
| Pressure Rating | PN40 / Class 300 / Class 600 / Class 900 |
| Body Material | WCB, WC6, WC9, CF8M (SS316) |
| Trim Material | SS316 + Stellite 6, 13Cr hard-faced |
| Bypass Control | Modulating multi-stage disc or piston with characterised opening |
| Minimum Flow Setting | Factory-set per pump curve; field adjustable ± 10% |
| Temperature Range | -29°C to +593°C (WC9) |
| End Connections | Flanged ASME B16.5, butt weld |
| Leakage Class | ANSI/FCI 70-2 Class IV (main), Class II (bypass) |
| Features | Integral check + bypass, no external power, self-acting |
Materials of Construction
| Component | Material |
|---|
| Body | WCB or WC6 / WC9 cast steel, one-piece body with integral bypass chamber |
| Main Disc | SS316 with Stellite 6 overlay, spring-assisted for rapid closing |
| Bypass Trim | SS316 multi-stage piston or disc with characterised flow slots |
| Seat | Integral SS316 with Stellite 6; replaceable seat ring for high-differential service |
| Spring | Inconel X-750 for high-temperature creep resistance |
| Packing | Graphite braided rings with anti-extrusion end rings |
| Gaskets | Spiral-wound SS316 + graphite for body/cover joint |
Testing & Inspection
| Test | Requirement |
|---|
| Test Standard | API 598 / IEC 60534-4 |
| Certification | CE, PED, ISO 9001, IBR |
Applicable Standards
| Standard | Description |
|---|
| Design Standard | ASME B16.34 / API 6D / IEC 60534 |
Notes
- Pump minimum flow must be calculated from manufacturer H-Q curve at shut-off head; submit pump curve at order for factory matching.
- Bypass opening pressure is set at factory; field adjustment is possible within ± 10% using spring pre-load screw.
- For high-differential boiler feed service (>150 bar), specify multi-stage labyrinth bypass trim with 4 to 6 pressure stages.
- Main check valve spring rate must be selected to close rapidly enough to prevent reverse rotation but not slam; specify pump inertia.
- IBR inspection and Form III-C certificate required for boiler feed pump applications in India; allow 3 weeks.
