A large liquid nitrogen dewar – typically 35 litres and above – is used in UK IVF clinics, sperm banks, and research institutions where sample volumes are high, refill frequency needs to be low, or long-term storage of patient material over multiple years is required. Size alone does not define suitability; canister configuration, evaporation rate, and neck diameter are equally important.
At what point does a lab need to move to a large dewar?
Most single-site IVF clinics operate comfortably with mid-range vessels of 20 to 34 litres. The step up to a large dewar – 35 litres or more – is typically triggered by one of three factors: a significant increase in cycle volume, the need to store samples long-term without frequent LN2 top-ups, or the consolidation of multiple smaller vessels into a single managed unit.
Does a larger dewar always have a lower evaporation rate?
Not automatically. A poorly insulated large vessel can lose more liquid nitrogen per day than a well-engineered smaller one. The quality of the vacuum jacket and the neck plug design determine evaporation rate far more than raw capacity. Always check the manufacturer’s stated static evaporation rate in litres per day, not just the total volume.
What access considerations apply to large dewars?
A 50-litre dewar filled with liquid nitrogen weighs approximately 70 to 80 kilograms. Labs need to plan for floor loading, access routes, and safe handling. A tipping trolley designed for LN2 vessels makes daily access and dispensing significantly safer and reduces the risk of manual handling injuries.
We have seen labs invest in a 50-litre vessel and then struggle to access samples safely because they did not account for the weight and height. Equipment specification should always include the handling setup, not just the vessel itself.
Cryolab supplies large liquid nitrogen dewars with optional handling accessories. View the CryoNest Series or get in touch to discuss your lab’s requirements.
