Dewar Flasks Made of Glass
Construction and Function of Dewar Flasks
Dewar flasks are double walled vacuum insulated flasks made of glass or metal, which have the task to thermally insulate a therein-stored product (LN2; CO2 etc.) against the ambient temperature. Dewar flasks consist of an inner and an outer recipient, whichare connected on top at the filling port. The space between the inner and the outer flask is vacuum insulated, to stop the heat contact between the product stored in the Dewar flask and the ambient temperature (contact warmth). Additionally, Dewar flasks made of glass have a silver coating in the vacuum space, in order to minimise the warmth radiation. The best possible insulation could be received by reducing the contact warmth and the radiation warmth.
Admissible Operation Conditions for Standard Glass Flasks
Temperature range Dewar -200°C to +200 °C Temperature range other components -10°C to +80 °C Pressure range depressurised
Standard -Dewar flasks are not appropriate for the use of liquid and gaseous helium. Special design is available on request.
Standards and Guidelines
All of the EMCLAB glassware are manufactured considering —Guideline of pressure devices", directive 97/23 EC and DIN 12492 "Equipment with vacuum insulation". Under the condition that there are any standards for joint parts such as spherical ground joints or conical ground joints, those will be utilised (e.g. DIN 12242-1 and DIN 12244-1).
Verifications
Each of the EMCLAB products is subject to individual verification and identification, as well as the documentation of all manufacturing data.