A cryogenic tank is a broad term covering any pressure or non-pressure vessel designed to contain cryogenic liquids at sub-zero temperatures. In laboratory use, the specific vessel type determines the application, safety profile, storage capacity, and operational requirements. Understanding the distinctions prevents both procurement errors and safety incidents.
Open-necked laboratory dewars are non-pressurised wide-mouth vessels used for small-volume liquid nitrogen dispensing, short-term biological sample cooling, and handling tasks. They are not suitable for long-term biological storage because evaporation rates are too high and they cannot be sealed to prevent oxygen ingress or contamination.
Cryogenic storage dewars, such as the CryoNest range from Cryolab, are purpose-engineered narrow-neck vessels with vacuum-jacketed insulation designed to minimise liquid nitrogen evaporation over extended periods. They accept internal racking systems for organised sample storage and are the standard vessel type for long-term biological sample repositories in IVF clinics, sperm banks, and biobanks. Pressurised cryogenic tanks are closed systems operating at pressures between 2 and 22 bar and are used for liquid nitrogen supply and distribution within facilities. These require pressure relief valves, burst discs, and installation by competent persons under the Pressure Systems Safety Regulations 2000.
Dry shippers, such as the CryoStork range from Cryolab, are a specialised liquid cryogenic storage option that hold liquid nitrogen in absorbent porous material within the vessel wall rather than as free liquid, generating vapour-phase cooling for specimen transport. They are IATA-compliant for air freight and eliminate the risk of liquid nitrogen spillage during transit. A full comparison of cryogenic storage options for UK laboratories is available at cryolab.co.uk/storage-vessels/.
