| 摘要 |
PURPOSE:A liquefied mixed gaseous composition for direct cooling or refrigerating, containing liquid nitrogen as a principal component and liquid oxygen in a controlled amount, capable of giving a safe working atmosphere without affecting the oxidation of a material to be cooled. CONSTITUTION:86-76mol% liquid nitrogen is mixed with 14-22mol% liquid oxygen to give the aimed liquefied mixed gaseous composition. The composition is prepared by mixing suitable amounts of the liquid oxygen with the liquid nitrogen. adding the liquid nitrogen to the liquid oxygen and adjusting the liquid oxygen content, or reducing the ratio between the oxygen and the nitrogen in air and liquefying the air. Preferably, the amount of the liquid oxygen is 18-22mol% in a refrigerator. For operating a freezer with a relatively opening environment, the amount is preferably 14-22mol%. |
