Frequently Asked Questions
What is a dewar? How are cryogenic dewars used? Find answers to these and other frequently asked questions from the experts at Cryofab.
A dewar—sometimes called a dewar flask or dewar container—is a two-walled vessel with a vacuum space between the inside and outside walls. This vacuum keeps the contents of the dewar cold by minimizing heat loss.
Because the vacuum space is a good insulator, dewars are used to keep super-cold liquids from turning back into gases. For instance, liquid nitrogen “boils off” or changes from a liquid to a gas at −320 °F (77K, −195.79 °C). Liquid helium boils off at an even lower -452.1°F (4 K, −269 °C).
Cryogenic dewars store, dispense or transport cryogenic gases.
These containers are useful across industries including in research, biopreservation, food processing, medical, military, and aerospace.
At Cryofab we start with a standard CF Series cryogenic dewar flask, a tried-and-true design with updated vacuum technology. It can be built in a wide range of sizes that and configured to serve in unlimited applications.
Depending on the plans for filling/dispensing, we can configure the dewar with:
- Built-in fill lines
- Side inlet/outlets
- Autofill systems
- Bottom drains
- Cover plates
To measure contents and view contents:
- Built-in level sensor lines
- Level controllers
For transporting liquid gases:
- Caster mounting
- Lifting lugs
Cryofab’s custom dewar containers have found their way from the lab into the outer reaches of industry and many other technology sectors. This does not begin to scratch the surface as to the many different configurations that have been fabricated for these dewars over the years. The answers to these questions will guide the design and fabrication for the perfect dewar flask for any application.
- How is this container going to be used?
- What liquid gas service will this be used for?
- Dimensional requirements? Inside opening? Depth?
- Are there pressure requirements?
- Do you require a flanged top termination?
- Is this incorporated into a product to be sold?
- What performance do you need from the dewar to meet the requirements of your application?