Cryogenic Gate Valve -- Flexible Wedge LNG / LPG SS316
Extended Bonnet Full-Port Isolation Valve for Ultra-Low Temperature Service
Document No.SV-DS-CRY-003
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers flexible wedge cryogenic gate valves with extended bonnet for bidirectional isolation in LNG, LPG, and liquid nitrogen systems. Full-port design allows pigging and inspection tool passage.
Technical Specifications
| Parameter | Specification |
|---|
| Valve Size Range | DN50 to DN600 (2" to 24") |
| Pressure Rating | PN40 / Class 150 / Class 300 / Class 600 |
| Body Material | CF8M (SS316) low-temp Charpy-tested at -196°C |
| Wedge Material | CF8M (SS316) flexible wedge with central hub for seat alignment |
| Seat Material | SS316 integral or overlay, optional PTFE insert for bubble-tight |
| Bonnet Extension | 200 mm to 500 mm per BS 6364 and operator size |
| Temperature Range | -196°C to +120°C |
| End Connections | Flanged ASME B16.5, butt weld ASME B16.25 |
| Operation | Handwheel, gear operator, or motorised actuator |
| Features | Full port, flexible wedge, extended bonnet, position indicator |
Materials of Construction
| Component | Material |
|---|
| Body | CF8M (SS316), solution annealed, Charpy impact tested at -196°C |
| Bonnet | CF8M (SS316), extended neck with position indicator boss |
| Wedge | CF8M (SS316) one-piece flexible wedge with centre hub for automatic seat alignment under differential pressure |
| Seat | Integral SS316 with optional Stellite 6 overlay; PTFE insert on request |
| Stem | SS316, rising stem with ACME threads, handwheel nut with thrust bearing |
| Packing | Graphite braided rings with anti-extrusion end rings, live-loading optional |
| Gaskets | Spiral-wound SS316 + graphite for body/bonnet joint |
Testing & Inspection
| Test | Requirement |
|---|
| Test Standard | API 598 / ISO 5208 / BS 6364 cold-box test |
| Certification | CE, PED, ISO 9001 |
Applicable Standards
| Standard | Description |
|---|
| Design Standard | BS 6364 / API 600 / ASME B16.34 |
Notes
- Flexible wedge design requires minimum differential pressure to seat; not recommended for vacuum or very low-differential service.
- Extended bonnet length must be confirmed against insulation thickness and predicted frost line height at site ambient.
- For buried or insulated installation, specify chain-wheel or extension spindle to bring operator above grade / insulation top.
- Valves are supplied with end protectors and nitrogen purge for transport; remove protectors just before welding.
- Butt-weld end preparation per ASME B16.25; maintain 3°C/min warming rate during first cool-down to prevent thermal shock.
