| 摘要 |
<p>A method and apparatus are disclosed for cryogenic treatment of materials, Liquefied gases are used for cooling instead of refrigeration units, thus avoiding maintenance of such units, and there are not the same constraints on chamber size as occurs with refrigeration units. The process comprises inserting a predetermined quantity of a liquid gas into an enclosed insulated container to vaporize, reduce the moisture content, and purge air; recirculating the vaporized gas within the container to maintain a substantially uniform temperature therein; cooling the container at a predetermined rate, and maintaining the container at a minimum temperature for a predetermined period of time; and heating the recirculating vaporized gas to raise the temperature at a predetermined rate. The apparatus comprises an enclosed, insulated container having a sealed lid in the top thereof, open evaporator for liquid gas within the container, recirculating fan and duct means for maintaining substantially uniform temperature within the container, a primary cooling coil for liquid gas within the container, main cooling coils for liquid gas within the container, and heating means within the duct means.</p> |
