| 摘要 |
<p>Refrigerant for a low temp. environmental test system comprises a mixture of (a) CF2Cl2, CHClF2 or an azeotrope of CHClF2 (e.g. 48.8%) and C2ClF5 (e.g. 51.2%) with (b) CClF3 or an azeotrope of CHF3 (e.g. 40.1%) and CClF3 (e.g. 59.9%). Component (a) is condensed from the mixture and separated from component (b) and component (b) is selectively condensed by counter-current evapn. of component (a) by heat exchange therewith. Permits the ready attainment of temps. as low as -85 degrees F in a simple and inexpensive unit formed of conventional and readily available component and the consequent availability of an inexpensive environmental test chamber construction having a markedly expanded operating test range.</p> |
