| 摘要 |
<p>Cold thermostatic flask of the Dewar type comprises an inside container with a projecting neck for filling, the container being surrounded by an envelope connected to the neck and enclosing an air-tight vacuum at a fixed distance. An anti-radiation screen of high thermal conductivity is fitted between the vessel and its envelope at a fixed distance and virtually enclosing the inner vessel. Part of the neck of the screen extends up the neck of the inner vessel, spaced from it and out of contact with it except for one main supporting connection which fixes the screen in its intermediate position. An aspiration tube or outlet hole may lead from the inside of the vessel to the open air and function as a heat-exchanger between the aspirated gas in the tube and the neck of the screen.</p> |
