Cooling device and methods of forming and regenerating same

Abstract

The present invention concerns a cooling device and method of forming and regenerating same for use in keeping perishable products cool. The cooling device includes a porous substrate that has been soaked in a first composition including at least one anti-freeze agent before being soaked in a second composition including at least one crosslinking agent and be exposed to UV irradiation. The cooling device further includes a substrate cover for sealingly covering the porous substrate after being soaked in the second composition and exposed to the UV irradiation. Prior to use, the cooling device is cooled to a desired temperature and exposed to further UV irradiation.

Claims

1. A cooling device for use in keeping perishable products cool, said device comprising: a porous substrate soaked in a composition comprising at least one anti-freeze agent and at least one crosslinking agent; and a substrate cover for sealingly covering the porous substrate, wherein said porous substrate is UV irradiated prior to being sealingly covered with the substrate cover, wherein said cooling device is cooled to a desired temperature prior to use, and wherein said composition comprises spermidine as the at least one crosslinking agent, and further comprises icilin.

2. The device of claim 1, wherein the porous substrate is a phenolic foam.

3. The device of claim 1, wherein the at least one anti-freeze agent is selected from ethanol, methanol, ethylene glycol, propylene glycol, polyethylene glycol, glycerol, urea, one or more salts, or any combination thereof.

4. The device of claim 3, wherein the one or more salts are selected from the group consisting of NaCl, CaCl.sub.2, MgCl.sub.2, and KCl.

5. The device of claim 1, wherein the composition comprises NaCl, propylene glycol, glycerol and ethanol as anti-freeze agents.

6. The device of claim 1, wherein the composition further comprises an aluminosilicate agent.

7. The device of claim 6, wherein the composition comprises zeolite the aluminosilicate agent.

8. The device of claim 1, wherein the composition comprises, as the anti-freeze agent: from about 0.5 wt % to about 10 wt % NaCl; from about 0.1 wt % to about 5 wt % propylene glycol; from about 0.1 wt % to about 5 wt % glycerol; and from about 0.1 wt % to about 10 wt % ethanol.

9. The device of claim 1, wherein the composition comprises from about 0.1 wt % to about 5 wt % spermidine as the crosslinking agent; and from about 0.001 wt % to about 0.001 wt % icilin; and further comprises from about 0.1 wt % to about 0.5 wt % zeolite as an aluminosilicate agent.

10. A method of preparing a cooling device for use in keeping perishable products cool, said method comprising: soaking a porous substrate in a composition comprising at least one anti-freeze agent and at least one crosslinking agent; exposing said porous substrate to UV irradiation; sealing said porous substrate in a substrate cover to obtain a sealed substrate; and cooling said sealed substrate to a desired temperature prior to use, wherein said composition comprises spermidine as the at least one crosslinking agent, and further comprises icilin.

11. The method of claim 10, wherein the soaking includes immersing or impregnating the porous substrate with the composition until substantially saturated.

12. The method of claim 10, wherein the exposing occurs for a period of time ranging from about 30 mins to about 4 hours.

13. The method of claim 10, wherein the porous substrate is soaked in the composition until it is saturated.

14. The method of claim 10, wherein the cooling comprises cooling to a temperature at which the sealed substrate soaked in the composition undergoes a phase transition into a substantially solid state.

15. The method of claim 10, wherein the cooling comprises rapidly cooling so that the sealed substrate undergoes a phase transition to a non-crystalline amorphous solid.

16. The method of claim 10, wherein the sealed substrate is exposed to further UV irradiation during the cooling.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

(2) FIG. 1 is a photograph of a cooling device according to an embodiment of the present invention;

(3) FIG. 2 is a photograph of a porous substrate of the cooling device as shown in FIG. 1 with a substrate cover removed;

(4) FIG. 3 is a schematic showing an exploded view of the porous substrate as shown in FIG. 2;

(5) FIG. 4 is a schematic showing a freezer and associated trolley for respective use in cooling and transporting the cooling device as shown in FIG. 1;

(6) FIG. 5 is a flowchart showing steps in a method of forming the cooling device as shown in FIG. 1 according to an embodiment of the present invention;

(7) FIG. 6 is a flowchart showing steps in a method of forming the cooling device as shown in FIG. 1 according to another embodiment of the present invention;

(8) FIG. 7 is a flowchart showing steps in a method of regenerating the cooling device as shown in FIG. 1 for re-use according to an embodiment of the present invention; and

(9) FIG. 8 is a flowchart showing steps in a method of regenerating the cooling device as shown in FIG. 1 for re-use according to another embodiment of the present invention.

DETAILED DESCRIPTION

(10) FIG. 1 shows a cooling device (100) according to an embodiment of the present invention.

(11) The cooling device (100) is for use in keeping perishable products cool. The cooling device (100) includes: a porous substrate (210; visible in FIGS. 2 and 3) that has been impregnated with a first composition including anti-freeze agents before being impregnated with a second composition including at least one crosslinking agent and being exposed to UV irradiation; and a substrate cover in the form of a metallised film (120) for sealingly covering the porous substrate (210; visible in FIGS. 2 and 3). Prior to use, the cooling device (100) is rapidly cooled to about −80° C. or lower.

(12) Referring to FIG. 2, the porous substrate (210) is formed from phenolic foam and is in the shape of a rectangular prism.

(13) The porous substrate (210) has two opposed surfaces, including an upper surface (212) and an opposed lower surface (214). The opposed surfaces extend substantially parallel to one another and are interconnected by opposing edges. The opposing edges include a pair of opposed side edges (216) and a pair of opposed end edges (218).

(14) Turning briefly to FIG. 3, the substrate (210) is formed from three substrate layers (310) joined together.

(15) As shown, the porous substrate (210) includes two inlets (320), two outlets (330) two internal circulation passageways (340) each configured to direct an injected composition from its respective inlet (320) to its respective outlet (330) along a tortuous passage extending between the opposed side edges (216) and opposed end edges (218). The inlets (320) and the outlets (330) are accessible from a common end edge (218).

(16) Each of the internal circulation passageways (340) are partly defined by the three substrate layers (310) of the porous substrate (210).

(17) Turning back to FIG. 1, the substrate (210; visible in FIGS. 2 and 3) is impregnated with a first composition including the following:

(18) TABLE-US-00001 Ingredient Amount (wt %) water 92 NaCl 4.0 propylene glycol 2.0 glycerol 1.0 ethanol 1.0

(19) The first composition is injected into the porous substrate (210; visible in FIGS. 2 and 3) via the respective inlets (320; visible in FIG. 3) by a syringe or by a pump.

(20) Once saturated with the first composition, the porous substrate (210; visible in FIGS. 2 and 3) is then impregnated with a second composition including the following:

(21) TABLE-US-00002 Ingredient Amount (wt %) water polyamine (spermidine) 1.6 Aluminium silicate (zeolite) 0.397 icilin 0.003

(22) Like with the first composition, the second composition is injected into the porous substrate (210; visible in FIGS. 2 and 3) via the respective inlets (320; visible in FIG. 3) by a syringe or by a pump.

(23) Once saturated with the second composition, the porous substrate (210; visible in FIGS. 2 and 3) is exposed to UV irradiation.

(24) In this regard, the porous substrate (210; visible in FIGS. 2 and 3) is placed within a sterile chamber having a UV light source capable of emitting UV irradiation. The porous substrate (210; visible in FIGS. 2 and 3) is exposed to the UV irradiation for a period of about four hours.

(25) The porous substrate (210; visible in FIGS. 2 and 3) is then sealingly covered by the substrate cover in the form of the metallised film (120) to obtain a sealed substrate.

(26) The metallised film (120) is sized and shaped to be wrapped about the porous substrate (210; visible in FIGS. 2 and 3) and then vacuum and heat sealed.

(27) The metallised film (120) includes a thermoplastic polymer (polyethylene telephthalate (PET)), an aluminium coating, and a polyurethane adhesive (for sealing the film once wrapped around the porous substrate).

(28) In some embodiments, the metallised film (120) further includes a polyamine (spermine) and a photoconductive polymer (poly(vinylcarbazole)).

(29) In some embodiments, the metallised film (120) further includes a plurality of pin hole-sized transparent windows (not visible) in the aluminium coating to, in use, admit UV irradiation for interaction with the underlying porous substrate (210; visible in FIGS. 2 and 3) to enable further crosslinking to occur when being cooled.

(30) In use, the photoconductive polymers are configured to absorb the UV irradiation and produce an increase of electrical conductivity of the metallised film (120).

(31) As with the impregnation, the porous substrate (210; visible in FIGS. 2 and 3) is wrapped and sealed in the metallised film (120) in the sterile chamber.

(32) Once sealingly covered in the metallised film (120), the cooling device (100) is rapidly cooled to about −80° C. or lower.

(33) Referring to FIG. 4, the cooling device (100) is rapidly cooled in a freezer (410).

(34) Advantageously, by rapidly cooling the cooling device (100), the soaked compositions are supercooled and pass through a glass transition to form a non-crystalline amorphous solid. By promoting the formation of a non-crystalline amorphous solid, elementary bonding becomes higher thus enhancing latent heat transfer of the cooling device (100).

(35) The cooling device (100) is cooled to a temperature of about −80° or lower for a period of about 4 hours.

(36) While cooling, the cooling device (100), in some embodiments, is simultaneously exposed to a second round of UV irradiation emitted periodically in pulses.

(37) In such embodiments, the cooling device (100) is exposed to the second round of UV irradiation for the entire time it is cooled.

(38) In some embodiments, the freezer (410) further includes an air ionizer for ionizing internal freezer air, or is supplied ionized air via an air circulation system connected to an air ionizer.

(39) In some embodiments, the freezer (410) further includes one or more electro magnets for generating a magnetic field within the freezer (410).

(40) Advantageously, the use of an air ionizer or ionized air during both the first and second rounds of UV irradiation and when cooling at least partially assists in promoting the supercooling of the cooling device by removing or preventing possible nucleation sites and thereby the formation of ice crystals.

(41) Moreover, the photoconductive polymers in the metallised film (120; shown in FIG. 1) becomes negatively charged when being exposed to the second round of UV irradiation, which, in turn, is thought to lower the freezing point of adjacent internal water molecules and thereby at least partially retard the outer surface of the porous substrate (210; visible in FIGS. 2 and 3) undergoing phase transition to a non-crystalline amorphous solid relative to a remainder of the porous substrate (210; visible in FIGS. 2 and 3) when being cooled.

(42) A method (500) of forming the cooling device (100) as shown in FIG. 1 and partly in FIGS. 2 and 3 according to an embodiment of the present invention will now be described in detail with reference to FIG. 5.

(43) At step 510, the porous substrate (210) is impregnated with the first composition including the anti-freeze agents. The porous substrate (210) is injected by syringe or pump with the first composition via the two inlets (320), two outlets (330) and two internal circulation passageways (340) each configured to direct the first composition from its respective inlet (320) to its respective outlet (330) along a tortuous passage extending between the opposed side edges (216) and opposed end edges (218).

(44) At step 520, the porous substrate (210) is impregnated with the second composition including at least one crosslinking agent. The porous substrate (210) is injected by syringe or pump with second composition in the same manner as described above with step 510.

(45) At step 530, the porous substrate (210) is placed within a sterile chamber having a UV light source capable of emitting UV irradiation. The porous substrate (210) is exposed to the UV irradiation for a period of about four hours. The UV irradiation causes the crosslinking agent in the second composition to crosslink with other polymers.

(46) At step 540, the porous substrate (210) is sealingly covered by the substrate cover in the form of the metallised film (120) to obtain a sealed substrate.

(47) The metallised film (120) is sized and shaped to be wrapped about the porous substrate (210) and then vacuum and heat sealed.

(48) As with the impregnation, the porous substrate (210) is wrapped and sealed in the metallised film (120) in the sterile chamber.

(49) At step 550, the sealed substrate is placed in the freezer (410) and rapidly cooled to a temperature of about −80° C. or lower to form the cooling device (100).

(50) The sealed substrate is rapidly cooled for a period of about 4 hours.

(51) The cooling device (100) is then ready for use.

(52) A method (600) of forming the cooling device (100) as shown in FIG. 1 and partly in FIGS. 2 and 3 according to another embodiment will now be described in detail with reference to FIG. 6.

(53) Steps 610-640 are identical to steps 510-540 as described above.

(54) At step 650, the sealed substrate is placed in the freezer (410) and rapidly cooled to a temperature of about −80° C. or lower while being exposed to the second round of UV irradiation to form the cooling device (100).

(55) The sealed substrate is rapidly cooled and exposed to UV irradiation for a period of about 4 hours.

(56) The cooling device (100) is then ready for use.

(57) A method (700) of regenerating a used cooling device (100) according to an embodiment of the present invention will now be described in detail with reference to FIG. 7.

(58) At step 710, a used cooling device (100) is provided, obtained or collected. The used cooling device (100) will typically be at ambient or near ambient temperature.

(59) At step 720, the used cooling device (100) is placed in the freezer (410) and rapidly re-cooled to a temperature of about −80° C. or lower to regenerate the cooling device (100).

(60) The used cooling device (100) is rapidly re-cooled for a period of about 4 hours.

(61) After step 720, the cooling device (100) is regenerated and ready to be re-used.

(62) A method (800) of regenerating a used cooling device (100) according to another embodiment of the present invention will now be described in detail with reference to FIG. 8.

(63) At step 810, a used cooling device (100) is again provided, obtained or collected. The used cooling device (100) will typically be at ambient or near ambient temperature.

(64) At step 820, the used cooling device (100) is placed in the freezer (410) and rapidly re-cooled to a temperature of about −80° C. or lower while being exposed to UV irradiation to regenerate the cooling device (100).

(65) The used cooling device (100) is rapidly re-cooled and exposed to UV irradiation for a period of about 4 hours.

(66) After step 820, the cooling device (100) is regenerated and ready to be re-used.

(67) In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

(68) Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

(69) In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

(70) The following are examples of the practice of the invention. They are not to be construed as limiting the scope of the invention in any way.

EXAMPLES

Example 1: Formulation Screening

(71) Exploratory formulation screening was conducted to identify key composition ingredients that enhance the length of time that the cooling device can maintain a temperature below 15° C.

(72) Testing was carried out in an airplane food galley of aluminium construction and having dimensions of 800 mm length, 300 mm width and 900 mm height. The galley has a volume of 216 litres. The galley was fitted with a temperature probe (RC-4HC with 10 cm probe).

(73) Cooling devices of the present invention were prepared with the following compositions prior to being cooled to −40° C. and −80° C., respectively, and then positioned on the second shelf of the galley. A conventional dry ice cooling device was also used as a comparative example.

(74) TABLE-US-00003 TABLE 1 Screened Compositions Formulation No. Ingredient Amount (wt %) 1 water 91.84 NaCl 3.06 glycerol 3.06 ethanol 2.04 2 water 93.88 NaCl 3.06 glycerol 3.06 3 water 93.88 glycerol 3.06 ethanol 3.06 4 water 96.94 glycerol 3.06 5 water 96.94 propylene glycol 3.06 6 water 91.84 propylene glycol 8.16 7 water 91.84 NaCl 8.16 8 water 91.84 NaCl 5.10 glycerol 3.06 9 water 86.74 NaCl 5.10 propylene glycol 4.08 glycerol 4.08 10 water 89.80 NaCl 5.10 propylene glycol 2.04 glycerol 1.53 ethanol 1.53 11 water 92.30 NaCl 4.10 propylene glycol 1.54 glycerol 1.03 ethanol 1.03 12 water 88.57 NaCl 3.94 propylene glycol 1.48 glycerol 0.98 ethanol 0.98 Icilin 0.01 zeolites 0.1 spermidine 3.94 13 water 89.37 NaCl 3.97 propylene glycol 1.49 glycerol 0.99 ethanol 0.99 Icilin 0.01 zeolites 0.2 spermidine 2.98 14 water 90.2 NaCl 4.00 propylene glycol 1.50 glycerol 1.00 ethanol 1.00 Icilin 0.005 zeolites 0.4 spermidine 2.00 15 water 90.1 NaCl 4.00 propylene glycol 1.5 glycerol 1.0 ethanol 1.0 Icilin 0.003 zeolites 0.4 spermidine 2.00

(75) The results of cooling devices soaked in the various formulations and cooled to −40° C. are presented in the following table.

(76) TABLE-US-00004 TABLE 2 Screening Results for cooling devices cooled to −40° C. Starting Formulation Temperature Time out of freezer (hrs) No. (° C.) 1 2 3 4 5 6 7 8 Dry Ice −79 10 13 13 15 15 16 17 T 1.sup.  −40 8 10 15 T 2.sup.  −40 8 10 16 T 3.sup.  −40 8 11 17 T 4.sup.  −40 9 12 18 T 5.sup.  −40 9 12 18 T 6.sup.  −40 9 13 19 T 7.sup.  −40 9 13 19 T 8.sup.  −40 9 13 18 T 9.sup.  −40 10 13 19 T 10 .sup.  −40 10 13 17 T 11 .sup.  −40 9 12 15 15 T 12 .sup.  −40 4 4 4 8 10 12 14 T 13 .sup.  −40 4 4 4 7 9 11 13 T 14 .sup.  −40 4 4 4 5.5 7 9 11 T 15 .sup.  −40 4 4 4 5.5 7 9 11 T 12A −40 4 4 4 7 9 11 13 T 13A −40 4 4 4 6 8 11 12 T 14A −40 4 4 4 5.5 7 8 10 T 15A −40 4 4 4 5 6 8 10 T 12B −40 4 4 4 7 9 11 13 T 13B −40 4 4 4 6 8 11 12 T 14B −40 4 4 4 5.5 7 8 11 T 15B −40 4 4 4 5 6 8 10 T 12C −40 4 4 4 7 9 11 13 T 13C −40 4 4 4 6 8 11 12 T 14C −40 4 4 4 5.5 7 8 10 T 15C −40 4 4 4 5 6 8 10 T

(77) In the above table, the letter “T” indicates the experiment was terminated because the cooling device reached a temperature of 15° C. or higher. Moreover and in regard to formulations nos. 12 to 15, further variations were carried out on cooling devices soaked in these formulations.

(78) For example, the letter “A” indicates that the substrate of the cooling device soaked in the particular formula was subsequently exposed to UV radiation for 2 mins.

(79) The letter “B” indicates that the cooling device was exposed to pulsed UV radiation while being cooled to −40° C.

(80) The letter “C” indicates that the cooling device was exposed to ionized air while being cooled to −40° C.

(81) The results of cooling devices soaked in the various formulations and cooled to −80° C. are presented in the following table.

(82) TABLE-US-00005 TABLE 3 Screening Results for cooling devices cooled to −80° C. Starting Formulation Temperature Time out of freezer (hrs) No. (° C.) 1 2 3 4 5 6 7 8 Dry Ice −79 10 13 13 15 15 16 17 T 1.sup.  −80 7 9 14 T 2.sup.  −80 7 9 15 T 3.sup.  −80 7 10 16 T 4.sup.  −80 8 11 16 T 5.sup.  −80 8 11 16 T 6.sup.  −80 8 11 18 T 7.sup.  −80 8 12 18 T 8.sup.  −80 8 12 17 T 9.sup.  −80 9 12 18 T 10 .sup.  −80 9 12 16 T 11 .sup.  −80 8 11 13 15 T 12 .sup.  −80 3 3 4 7 10 12 14 T 13 .sup.  −80 3 3 4 6 9 11 13 T 14 .sup.  −80 3 3 4 5 5 8 11 T 15 .sup.  −80 3 3 4 5 5 8 11 T 12A −80 3 3 4 7 9 11 13 T 13A −80 3 3 4 6 8 11 12 T 14A −80 3 3 4 5 5 7 10 T 15A −80 3 3 4 5 5 7 10 T 12B −80 3 3 4 7 9 11 13 T 13B −80 3 3 4 6 8 11 12 T 14B −80 3 3 4 5 6 7 10 T 15B −80 3 3 4 5 6 7 10 T 12C −80 3 3 4 7 9 11 13 T 13C −80 3 3 4 6 8 11 12 T 14C −80 3 3 4 5 6 7 10 T 15C −80 3 3 4 5 6 7 10 T

(83) Again, in the above table, the letter “T” indicates the experiment was terminated because the cooling device reached a temperature of 15° C. or higher. Moreover and in regard to formulations nos. 12 to 15, further variations were again carried out on cooling devices soaked in these formulations.

(84) The letter “A” indicates that the substrate of the cooling device soaked in the particular formula was subsequently exposed to UV radiation for 2 mins. The letter “B” indicates that the cooling device was exposed to pulsed UV radiation while being cooled to −40° C. The letter “C” indicates that the cooling device was exposed to ionized air while being cooled to −40° C.

Example 2: Cooling Device Testing

(85) Testing was conducted to measure the cooling effect the cooling device has on an airplane food galley of aluminium construction and having dimensions of 800 mm length, 300 mm width and 900 mm height. The galley has a volume of 216 litres and has no insulation. The galley was fitted with a temperature probe (RC-4HC with 10 cm probe) and has been stocked with representative contents, including about 40% perishables and 60% water and alcoholic beverages.

(86) The stocked galley was stored in a cold room for four hours at 2° C. before being left at room temperature to simulate transit of the galley to an aircraft. Thereafter, the galley was stored at about 22° C. to simulate an aircraft environment.

(87) The galley was fitted with a cooling device of the present invention that has been soaked in a composition containing: 90 wt % water, 4 wt % NaCl, 2 wt % propylene glycol, 1 wt % glycerol, 1 wt % ethanol, 1.6 wt % spermidine bioreagent (>98%), 0.3997 wt % Zeolite and 0.003 wt % Icilin (>97%; HPLC), prior to being cooled to −80° C. for at least four hours.

(88) A conventional dry ice cooling device was used as a comparative example.

(89) The results are presented in the following table.

(90) TABLE-US-00006 TABLE 4 Results Description Dry Ice Cooling Device Galley Starting Temperature 25° C. 27° C. prior to being fitted with Dry Ice or Cooling Device Time to drop under 10° C. Less than 12 mins Less than 10 mins Time under 5° C. 2 hours 4 hours Time under 10° C. 2.5 hours 7 hours Time under 15° C. 4.5 hours 11 hours

Example 3: In-Flight Cooling Device Testing

(91) In-flight testing was conducted to measure the cooling effect the cooling device on an airplane food galley of aluminium construction and having dimensions of 800 mm length, 300 mm width and 900 mm height. The galley has a volume of 216 litres and has no insulation. The galley was fitted with a temperature probe (175T3 with external probe and air sensor) and has been stocked with typical aircraft food and beverage contents, including about 40% perishables and 60% water and alcoholic beverages.

(92) The stocked galley was stored in a cold room for four hours at 2° C. before being fitted with the cooling device and transited to an aircraft flying an Australian domestic route between Sydney and Hobart.

(93) The cooling device of the present invention has been soaked in a composition containing: 90 wt % water, 4 wt % NaCl, 2 wt % propylene glycol, 1 wt % glycerol, 1 wt % ethanol, 1.6 wt % spermidine bioreagent (>98%), 0.3997 wt % Zeolite and 0.003 wt % Icilin (>97%; HPLC), prior to being cooled to about −80° C. for at least four hours.

(94) The galley when fitted with the cooling device maintained a temperature below 10° C. for the seven hour duration of the flight (6 am to 1 pm).