| 摘要 |
A food refrigeration system 10 for refrigerating articles of, for example, food, includes at least two cooling stages formed by a water cooler 154 and a cryogenic freezer 16. The cryogenic freezer 16 receives the articles of food and transfers heat from the articles of food to a liquid cryogen (liquid nitrogen) so that the articles of food are refrigerated. The transfer of heat from the articles of food to the cryogen causes the cryogen to boil and thereby evolve a cryogenic vapour. The cooler 14 receives the articles of food prior to the cryogenic freezer 16 and transfers heat from the articles of food to the cooling water. Such heat transfer reduces the quantity of cryogen required to refrigerate the articles of food. An eductor 50 is connected to a pump 62 and to vent duct 72 from the cryogenic freezer 16. The cooling water is pumped through the eductor 50 to suck cryogenic vapour from the cryogenic freezer 16 and to mix the cryogenic vapour and the cooling water prior to reception of the cooling water in the cooler 14. Such mixing transfers heat from the cooling water to the cryogenic vapour resulting in an increase the heat transfer between the articles and the cooling water in the cooler 14. As a result of such increased heat transfer, the amount of cryogen required in refrigerating the articles is reduced. <IMAGE> |
