What is an LN2 dewar and what do labs need to know before buying one?

An LN2 dewar is a vacuum-insulated vessel designed to store liquid nitrogen and, by extension, to maintain the cryogenic environment that keeps biological samples viable over long periods. The term dewar comes from James Dewar, who developed the vacuum flask principle in the late nineteenth century. Modern LN2 dewars used in clinical and research settings are considerably more sophisticated, with carefully engineered insulation systems, canister configurations, and neck seal designs specific to their application.

What sizes do LN2 dewars come in?

LN2 dewars are available from under 10 litres to several hundred litres. In IVF and andrology settings, the most commonly used sizes are 20 litres, 35 litres, and 50 litres for working storage, with larger vessels used for archive or satellite storage. Dry shippers are a specialist category of LN2 dewar designed for transport rather than storage.

How does vacuum insulation work in an LN2 dewar?

The insulation in an LN2 dewar is created by evacuating the space between the inner and outer walls of the vessel. This vacuum layer prevents heat transfer by conduction and convection, leaving only radiation as a heat pathway. Reflective surfaces on the inner walls further reduce radiative heat gain. The quality and longevity of the vacuum is the primary determinant of long-term dewar performance.

What goes wrong with LN2 dewars over time?

Vacuum degradation is the primary failure mode. If the vessel is knocked, dropped, or handled roughly, the vacuum can be compromised. Rising evaporation rates without a change in access patterns are the typical symptom. A dewar with failed insulation will not maintain adequate temperatures and should be replaced rather than used for sample storage.

Which LN2 dewars does Cryolab supply?

Cryolab supplies a full range of LN2 dewars for clinical and research use, including the CryoCan 47-10 for ten canister 50 litre storage and the CryoNest XL for larger capacity applications. All vessels are supplied with full canister and consumable accessories from a single source. Visit cryolab.co.uk.