| 摘要 |
<p>PCT No. PCT/AU95/00241 Sec. 371 Date Dec. 9, 1996 Sec. 102(e) Date Dec. 9, 1996 PCT Filed Apr. 21, 1995 PCT Pub. No. WO95/29372 PCT Pub. Date Nov. 2, 1995A refrigeration system (12) is comprised of three expansion units (19A, 19B, 19C), with each having an expansion chamber (22) and three secondary chambers (24, 26 and 28), connected to a supply (16) of compressed refrigerant. The expansion chamber and secondary chambers are formed with progressively reducing volumetric capacity. The end of each of the the secondary chambers, is connected to a common bleed tube (29) having a bleed hole (34) for venting the refrigerant. The bleed hole opens to the outside of a housing (15) which houses the expansion units. The interior of the housing (15) is filled with a gel which changes state from a liquid to a solid at a predetemmined temperature. A valving arrangement (32) connects the expansion units to a supply of compressed refrigerant. The housing (15) together with a supply (16) refrigerant can be installed into a cooling box for cooling the space within the cooling box. This is achieved by the valve mechanism (32) periodically admitting a volume of compressed refrigerant into the expansion units, wherein the compressed refrigerant initially expands in the expansion chambers. This in turn absorbs heat from the space within the box. The flow of expanded refrigerant through the secondary chambers is retarded by back pressure produced by having the secondary chambers of progressively reducing volumetric capacity. This allows the gel to be maintained at a frozen state for a long period of time while consuming only small volumes of compressed refrigerant.</p> |
