| 摘要 |
For use in a refrigeration system, at least two coolers are provided symmetrically on opposite sides of a rotatable thermal shield plate separating the compartment to be refrigerated from the area outside the compartment. Defrosting method comprises alternately placing two coolers inside and outside the compartment at regular intervals in such a manner that one cooler placed inside is actuated for entering the refrigeration cycle while the other placed outside is disactuated out of the refrigeration cycle for having the accumulated frost or ice removed by melting in a higher temperature atmosphere. The alternate cooling and defrosting operations for each of the coolers are continuously repeated so that the compartment to be refrigerated can always be maintained at appropriate cooling temperatures. Cooling apparatus comprises a thermal shield plate turnably provided in an opening in one of the surrounding side walls, at least two symmetrical coolers on opposite sides of the shield plate each having an evaporator, an electromagnet valve in the evaporator for opening and closing the path or flow of a refrigerant liquid, and covering means on opposite sides of the aforesaid one side wall for hermetically enclosing the opening in the wall and having a water discharge outlet. The evaporators form a closed circuit by interconnecting each other, and the circuit has a port from which a refrigerant liquid is introduced and a port from which a vapor is discharged. The electromagnet valves are alternately operated so that the valve for the evaporator inside can allow a refrigerant liquid to flow thereinto and a vapor to flow out while the valve for the evaporator outside is closed.
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