Industrial Check Valves
In a swing check valve a hinged disc opens with the flow and, when flow stops or reverses, closes onto the seat under its own weight and reverse pressure. With most of the flow path clear when fully open, the pressure drop is low.
Overview
The bolted bonnet gives easy access to the disc and seat; a renewable (threaded or welded) seat ring extends service life. Pipeline versions (API 6D) provide a full opening suitable for pigging. On pump lines with a high water hammer risk, closing speed can be adjusted with a counterweight or damper; for a compact solution, a dual plate check valve can be considered. For an overview of check valve designs, see check valve types explained.
Technical specifications
| Size | 2″–60″ (DN50–DN1500); larger sizes on a project basis |
|---|---|
| Pressure class | ASME Class 150–2500 |
| End connections | RF / RTJ flanged, butt-weld |
| Bonnet | Bolted; pressure seal in high classes |
| Seat | Renewable (threaded or welded) ring; Stellite hard-facing option |
| Materials | WCB, LCC, WC6, CF8M; duplex |
| Options | Counterweight, external lever, damper; piggable design |
Key features
- Low pressure drop
- Easy maintenance: bolted bonnet and renewable seat
- Closing control with counterweight
- Piggable pipeline version
Face-to-face dimensions (mm)
Flanged face-to-face dimensions of BS 1868 / API 6D swing check valves (ASME B16.10):
| NPS | DN | Class 150 | Class 300 | Class 600 |
|---|---|---|---|---|
| 2 | 50 | 203 | 267 | 292 |
| 2½ | 65 | 216 | 292 | 330 |
| 3 | 80 | 241 | 318 | 356 |
| 4 | 100 | 292 | 356 | 432 |
| 6 | 150 | 356 | 444 | 559 |
| 8 | 200 | 495 | 533 | 660 |
| 10 | 250 | 622 | 622 | 787 |
| 12 | 300 | 698 | 711 | 838 |
| 14 | 350 | 787 | 838 | 889 |
| 16 | 400 | 864 | 864 | 991 |
| 18 | 450 | 978 | 978 | 1092 |
| 20 | 500 | 978 | 1016 | 1194 |
| 24 | 600 | 1295 | 1346 | 1397 |
Values are for raised-face (RF) flanged ends and conform to ASME B16.10. Ring-type joint (RTJ) ends are slightly longer; butt-weld (BW) end-to-end dimensions are listed separately in the standard. Exact dimensions are shown on the general arrangement (GA) drawing supplied with the quotation.
Typical part materials
| Part | Carbon steel | Low temperature | Stainless steel | Alloy steel (high temperature) |
|---|---|---|---|---|
| Body, cover, disc | A216 WCB | A352 LCB / LCC | A351 CF8, CF8M, CF3, CF3M | A217 WC6, WC9, C5 |
| Seat ring | A105N (hardfaced) | A350 LF2 | Same stainless grade as body | A182 F11, F22, F5 |
| Hinge and pin | A216 WCB / A182 F6a | A352 LCB / A182 F304 | Same as body / F316 | A217 WC6 / A182 F6a |
| Stud bolts / nuts | A193 B7 / A194 2H | A320 L7 / A194 7 | A193 B8, B8M / A194 8, 8M | A193 B16 / A194 4 |
In all material groups, the standard gasket is spiral-wound SS304/SS316 with graphite filler and the standard packing is flexible graphite (PTFE on request). The stem nut is austenitic ductile iron (A439 D2) or copper alloy, and the handwheel is malleable iron. For sour (H₂S) service, materials and hardness are selected to NACE MR0175 / ISO 15156.
Documentation and testing
On industrial projects the documentation package matters as much as the valve. We confirm the certificate and test scope for every line item at quotation stage:
- EN 10204 3.1 material certificates for pressure-retaining and wetted parts, traceable by heat number
- EN 10204 3.2 with third-party inspection, on request
- Pressure test reports to API 598 or EN 12266-1: shell, seat and, where specified, gas tests
- Fire-test certificates (API 607 / ISO 10497) for fire-safe type-tested designs
- PMI reports for alloy and stainless materials
- Dimensional, visual and coating inspection records
- PED 2014/68/EU CE declaration for equipment within its scope
- NACE MR0175 / ISO 15156 compliance statement for sour (H₂S) service
Technical datasheet
Frequently Asked Questions
Can a swing check valve be installed in a vertical line?
Suitable designs can be used with vertical upward flow; however, because disc closure relies on gravity, they should not be used with vertical downward flow. Confirm the installation orientation with the manufacturer.
Related products
Dual Plate Wafer Check Valve
API 594; spring-assisted fast closing, short length; wafer, lug or flanged.
View details
Axial Flow Nozzle Check Valve
2″–60″, Class 150–1500; spring-loaded disc, non-slam closing, low pressure drop.
View detailsRequest a quote: Swing Check Valve
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