Double-Ended Cylinders
- Each DOT cylinder is hydrostatically tested to at least 5/3 the working pressure. All testing of DOT cylinders is witnessed by a DOT-approved independent inspection agency.
- DOT-3E 1800/TC-3EM 124 cylinders are hydrostatically proof tested at 3050 psig (210 bar). One cylinder of each lot is burst tested.
- DOT-3A 1800 and 5000/TC-3ASM 124 and 344 cylinders are marked with a serial number. Volumetric expansion of each cylinder during hydrostatic testing must be within the limits set by DOT Specification 3A and TC Specification 3ASM.
- DOT-3A 1800/TC-3ASM 124 cylinders are hydrostatically proof tested at 3000 psig (206 bar) minimum.
- DOT-3A 5000/TC-3ASM 344 cylinders are hydrostatically proof tested at 8500 psig (586 bar) minimum.
- DOT-SP7458 1800 cylinders are hydrostatically proof tested at 3000 psig (206 bar).
Single-Ended Cylinders
- DOT-4B 500 cylinders are hydrostatically proof tested at 1000 psig (69 bar) minimum.
Ministure Sample Cylinders
- Every miniature sample cylinder is proof tested at 1667 psig (114 bar) with dry nitrogen gas.
Overpressure Protection
Compressed gas cylinders must be equipped with pressure relief devices in accordance with United States DOT regulations and CGA S-1.1.
Rupture Disc Units
Swagelok rupture disc units protect sample cylinders from overpressurization by venting the cylinder contents to atmosphere. The rupture disc is welded to a body that is threaded into a valve body or a rupture disc tee and sealed by an elastomer O-ring. Nonrotating stem needle valves with rupture disc units and rupture disc tees are also available.
Options and Accessories
PTFE coating- Electropolishing
- Additional marking
- End caps
- Caps and plugs
- Carrying handle
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1. Outage tube 3. Vapor space
2. Liquid 4. Total volume |
Outage Tubes
Outage tubes provide a vapor space of the desired volume in cylinders containing liquefied gases, so that liquid in the cylinder can expand if the temperature increases. Without enough vapor space, a small temperature increase can cause the liquid to expand and increase the pressure dramatically. See local regulations and other appropriate guidelines for safe filling limits for your application.