Cryogenic Valves
Cryogenic ball valves are used for isolation on LNG, liquid nitrogen, liquid oxygen and argon lines. An extended bonnet protects the packing from the cold, and unidirectional cavity relief prevents liquid trapped in the body cavity from vaporizing and building up pressure.
Overview
Cavity relief is usually to the upstream side, through the upstream seat, and is marked by an arrow on the valve body; the valve must be installed accordingly. Bodies are austenitic stainless steel such as CF8M, CF3M, F316 or F316L. In addition to routine tests at ambient temperature, low-temperature helium leak testing is performed as a type test or, on request, on valves selected from production. For oxygen service, oil-free (degreased) cleaning and compatible lubricants are used. For design and test requirements, see our BS 6364 cryogenic valve guide.
Technical specifications
| Type | Floating (small sizes), trunnion mounted (large sizes) |
|---|---|
| Temperature | Down to −196 °C (−321 °F) |
| Design | Extended bonnet, unidirectional cavity relief, antistatic, fire-safe option |
| Materials | CF8M, CF3M, F316, F316L |
| End connections | RF flanged, butt-weld, socket-weld |
| Testing | Routine tests at ambient temperature; −196 °C helium test to BS 6364 / ISO 28921 as a type test or on request |
Key features
- Extended bonnet keeps the packing from freezing
- Relief against cavity overpressure
- Helium leak test at −196 °C on request
- Cleaning suitable for oxygen service
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
Why is a cryogenic ball valve unidirectional?
Liquefied gas trapped in the body cavity vaporizes as it warms, and pressure rises rapidly. To relieve this pressure, one of the seats is designed to vent the cavity to the upstream side; the valve therefore seals in one direction only, and the installation direction matters.
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