Dewar Flasks
  • All glass products are manufactured from 33 expansion, low-extractable borosilicate glass conforming to USP Type I and ASTM E438, Type I, Class A requirements.
  • The KIMBLE® KIMAX® Dewar Flask is fully jacketed with aluminum and has viewing ports designed to visually inspect the contents through the strip-silvered glass.
  • The KIMBLE® KONTES® Vacuum Trap Flask, used as a connection to the Dewar vacuum flask, has a single long neck with a standard taper outer joint and is available in 500 mL and 1000 mL capacities.

Dewar Flasks FAQs

Dewar Flasks

Frequently Asked Questions

A laboratory Dewar flask (also known as a Dewar vessel) is an insulated but non-pressurized vessel that holds and stores cryogenic liquids (also known as cryogens). Typically, Dewar flasks are double-walled and vacuum-insulated between the two walls. Some Dewars have more than two walls. The role of the vacuum is to provide thermal insulation for short- to long-term storage of cryogens. Dewars may also be made of foam insulation for temporary storage only.

The design of a Dewar flask dictates how liquid can be decanted. Dewar flasks may be carefully tilted to allow the liquid out. Alternatively, Dewar flasks may rely on the gas pressure at the top of the Dewar to force the liquid upward through a pipe.

Aluminum insulates well, making it thermally efficient at extremely low temperatures and an excellent material for storing cryogens. Additionally, Dewar flasks fully jacketed with aluminum are lightweight and easier to transport.