TEMPERATURE CONTROLLED STORAGE CONTAINER

Abstract

A passive cold storage container, notably a vaccine transport container, comprises: —a product storage compartment (11); —one or more ice-pack compartment(s) (14-17) arranged adjacent to the product storage compartment, the ice-pack compartment(s) being spaced from the product storage compartment by a thermal barrier (26-30); and —a thermally insulated envelope (18) surrounding the product storage compartment and the ice-pack compartment(s). The thermal barrier comprises a phase change material having a solid/liquid transition temperature which is ≥1.0° C. and ≤10° C. The configuration provides user-independent freeze-free protection.

Claims

1-15. (canceled)

16. A passive cold storage container comprising: a product storage compartment; one or more ice-pack compartment(s) arranged adjacent to the product storage compartment, the ice-pack compartment(s) being spaced from the product storage compartment by a thermal barrier; and a thermally insulated envelope surrounding the product storage compartment and the ice-pack compartment(s); wherein the thermal barrier comprises a phase change material having a solid/liquid transition temperature which is 1.0° C. and 10° C.; and the phase change material comprises a self-supporting sheet of phase change material comprising a phase change polymer retained when in its liquid state by a supporting fibre structure and having the form of a flexible sheet having a thickness in the range 3 mm to 15 mm; and the thermal barrier comprises: the phase change material provided in the form of a first layer; and a layer of thermal insulation provided by insulating foam provided in the form of a second layer.

17. The passive cold storage container of claim 16, wherein the thermal barrier further comprises a vertical temperature distribution element of a thermally conductive material.

18. The passive cold storage container of claim 17, wherein the vertical temperature distribution element is provided by a sheet of metal.

19. The passive cold storage container of claim 17, wherein the thermal barrier comprises, in order, from the ice-pack compartment(s) to the product storage compartment: the vertical temperature distribution element; the layer of thermal insulation; and the layer of phase change material.

20. The passive cold storage container of claim 16, wherein the cold storage container is a Grade A (user-independent) freeze protected storage container as defined by the World Health Organisation PQS requirements in force on 1 Jun. 2019.

21. A passive cold storage container comprising: a product storage compartment; one or more ice-pack compartment(s) arranged adjacent to the product storage compartment, the ice-pack compartment(s) being spaced from the product storage compartment by a thermal barrier; and a thermally insulated envelope surrounding the product storage compartment and the ice-pack compartment(s); wherein the thermal barrier comprises a phase change material having a solid/liquid transition temperature which is 1.0° C. and 10° C.; and the phase change material comprises a self-supporting sheet of phase change material comprising a phase change polymer retained in its liquid state by a supporting fibre structure.

22. The passive cold storage container of claim 21, wherein the phase change material is the form of a flexible sheet having a thickness in the range 3 mm to 15 mm.

23. The passive cold storage container of claim 22, wherein the product storage compartment is provided in the form of a central air-filled column within the cold storage container and has a circular cross-section.

24. The passive cold storage container of claim 21, wherein the phase change material has a latent heat of fusion in the range 100 J/g to 300 J/g.

25. The passive cold storage container of claim 21, wherein the thermal barrier comprises: the phase change material provided in the form of a first layer and a layer of thermal insulation provided by insulating foam provided in the form of a second layer.

26. The passive cold storage container of claim 25, wherein the thermal barrier comprises a vertical temperature distribution element of a thermally conductive material provided by a sheet of metal.

27. A passive cold storage container comprising: a product storage compartment; one or more ice-pack compartment(s) arranged adjacent to the product storage compartment, the ice-pack compartment(s) being spaced from the product storage compartment by a thermal barrier; and a thermally insulated envelope surrounding the product storage compartment and the ice-pack compartment(s); wherein the thermal barrier comprises a phase change material having a solid/liquid transition temperature which is 1.0° C. and 10° C.; and the thermal barrier comprises a vertical temperature distribution element of a thermally conductive material provided by a sheet of metal.

28. The passive cold storage container of claim 27, wherein the thermal barrier provides a continuous barrier which separates the product storage compartment from the ice-pack compartment(s); and wherein the thermal barrier further comprises the phase change material provided in the form of a first layer and a layer of thermal insulation provided by insulating foam and provided in the form of a second layer.

29. The passive cold storage container of claim 28, wherein the thermal barrier comprises, in order, from the ice-pack compartment(s) to the product storage compartment: the vertical temperature distribution element; the layer of thermal insulation; and the layer of phase change material.

30. The passive cold storage container of claim 27, wherein the phase change material comprises a self-supporting sheet of phase change material comprising a phase change polymer retained in its liquid state by a supporting fibre structure.

31. The passive cold storage container of claim 30, wherein the product storage compartment is provided in the form of a central air-filled column within the cold storage container and has a circular cross-section.

32. The passive cold storage container of claim 16, wherein the phase change material has a solid/liquid transition temperature which is ≥2° C. and ≤8° C.

33. The passive cold storage container of claim 16, wherein the product storage compartment contains vaccines.

34. The passive cold storage container of claim 21, wherein the cold storage container is a Grade A (user-independent) freeze protected storage container as defined by the World Health Organisation PQS requirements in force on 1 Jun. 2019.

Description

[0020] Embodiment of the inventions will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0021] FIG. 1 and FIG. 2 are a perspective views of a test apparatus;

[0022] FIG. 3a, FIG. 3b, FIG. 3c and FIG. 3d are perspective, partially exploded views of thermal barriers tested;

[0023] FIG. 4a is a cross section through a vaccine storage container and FIG. 4b is an enlarged view of a portion of FIG. 4a; and

[0024] FIG. 5a is a perspective view of an alternative vaccine storage container, FIG. 5b is a cross section view of the base of this alternative vaccine storage container, FIG. 5c is an enlarged view of a portion of FIG. 5b and FIG. 5d is a perspective view of the sleeve used in this alternative vaccine storage container.

[0025] The test apparatus 10 illustrated in FIG. 1 and FIG. 2 comprises a simulated product storage compartment 11 defined within a sleeve 12. The sleeve had a square cross-section with rounded corners, cross-sectional dimensions of about 12 cm×12 cm and a height of about 19 cm; it was made of 2.5 mm thick PET. Temperature sensors 21, 22, 23, 24, 25 were arranged on a 1 mm thick PET support plate 13 arranged diagonally within the sleeve 12 to measure the temperature at the following positions within the product storage compartment 11: 21 bottom left corner; 22 bottom right corner, 23 top left corner; 24 top right corner; 25 centre. An individual 0.6 litre ice-pack 14, 15, 16, 17 was arranged against each of the four vertical, external walls of the sleeve 12. The sleeve 12 and the ice-packs 14, 15, 16, 17 were surrounded by a thermally insulated envelope provided by five 50 mm thick polyurethane insulating foam plates 18 glued together to form an open box with a sixth such insulating foam plate (not shown) being secured as a lid to the open box for the temperature monitoring tests. This arrangement simulates a passive vaccine carrier and was used to test the configurations of thermal barriers described below.

[0026] Each test was conducted by in the following way:

The test apparatus 10 was arranged in a test chamber whose temperature was maintained at the test temperature of +15.0° C. (±0.5° C.) or +43.0° C. (±0.5° C.)
Step 1: Stabilize the test apparatus 10 in the test chamber at the test temperature with the lid open.
Step 2: Fully freeze ice-packs 14, 15, 16, 17 at −25.0° C. (±0.5° C.); transfer the frozen ice-packs directly from their freezer to the test apparatus (without conditioning) and immediately close the lid of the test apparatus and start the temperature monitoring.
Step 3: Monitor the temperatures at one minute intervals.
The tests did not use a dummy vaccine load.

[0027] The thermal barriers tested are illustrated in the partially exploded views of FIGS. 3a to 3d.

[0028] In the FIG. 3a configuration, the thermal barrier comprised, in order from the ice packs to the product storage compartment 11: two layers 26, 27 of 10 mm thick expanded polypropylene foam insulation and the PET sleeve 12.

[0029] In the FIG. 3b configuration, the thermal barrier comprised, in order from the ice packs to the product storage compartment 11: a 10 mm thick expanded polypropylene foam insulation layer 26; a 5 mm thick layer of phase change material 28; a 2 mm thick aluminium plate 30, and the PET sleeve 12.

[0030] In the FIG. 3c configuration, the thermal barrier comprised, in order from the ice packs to the product storage compartment 11: two 5 mm thick layer of phase change material 28, 29 and the PET sleeve 12.

[0031] In the FIG. 3d configuration, the thermal barrier comprised, in order from the ice packs to the product storage compartment 11: a 10 mm thick expanded polypropylene foam insulation layer 26; a 5 mm thick layer of phase change material 28; and the PET sleeve 12.

[0032] In each configuration: [0033] the thermal barrier provided a continuous, uninterrupted separation between the ice-packs 14, 15, 16, 17 and the product storage compartment 11; [0034] each layer of polypropylene insulation 26,29 (when present) extended around the entire periphery of the product storage compartment 11 and over the full height of the product storage compartment 11; [0035] the aluminium plate 30 (when present) extended around the entire periphery of the product storage compartment 11 and over the full height of the product storage compartment 11; [0036] the layer(s) of phase change material (when present) had a liquid/solid transition temperature of about 5° C. and a latent heat of the fusion of about 180 J/g and comprised granulated of a paraffin- or wax-like nature retained in both solid and liquid states on a polymeric sheet network.
In the configuration of FIG. 3b, the layer of phase change material 28 extended around the entire periphery of the product storage compartment 11 from the base of the product storage compartment 11 to a position about halfway up the vertical height of the product storage compartment 11.
In the configurations of FIGS. 3c and 3d, the layer(s) of phase change material 28,29 extended around the entire periphery of the product storage compartment 11 and over the full height of the product storage compartment 11.

[0037] In the tables below, Table 1 shows test results at 15° C. and Table 2 shows test results at 43° C.

TABLE-US-00001 TABLE 1 Configuration tested at 15° C. 3a 3b 3c 3d Lowest temperature of −9.2° C. 1.7° C. 1.4° C. 1.3° C. any temperature sensor

TABLE-US-00002 TABLE 2 Configuration tested at 43° C. 3a 3b 3c 3d Lowest 1.9° C. 7.3° C. 3.2° C. 4.7° C. temperature of any tempera- ture sensor Cool down <1 h <2 h 40 min <1 h <1 h 46 min (10° C.) Cold life >26 hours >26 hours >29 hours >28 hours (10° C.)

[0038] As shown in Table 1, when tested at 15° C. the temperature in the product storage compartment of configurations 3b, 3c and 3d remained above 0.0° C.; these configurations were thus user-independent freeze-free when tested at 15° C. This was not the case for configuration 3a for which the temperature in the product storage compartment fell below 0.0° C.

[0039] Table 2 indicates that configuration 3c is particularly advantageous in terms of having both a long cold life and a rapid initial drop in the temperature of the products storage compartment to a temperature <10° C.

[0040] The passive vaccine storage container 40 illustrated in FIG. 4a and FIG. 4b comprises a base 41 which houses a vaccine storage compartment 42 and a removable lid 43. The product storage compartment 42 is an air-filled compartment whose base 42a and sidewalls 42b are defined by a plastics liner or cage 44 within which vials of vaccine (not shown) are placed for storage and transport. A top of the vaccine storage compartment 42 is preferably provided with a removable, insulated vaccine compartment lid 42c; alternatively, the lid 43 of the vaccine storage container 40 may provide a lid for the vaccine compartment 42. Ice-packs 45 are housed in ice-pack compartments 46 which are arranged adjacent to the vaccine storage compartment 42; the ice pack compartments 46 are spaced from the vaccine storage compartment 42 by a thermal barrier 47 which comprises, in order form the icepack compartment 46 to the product storage compartment 42: an aluminium plate 48 which provides a vertical temperature distribution element and which also serves to provide part of a housing for the thermal barrier 47 and for the ice-pack compartment 45; a layer of thermal insulation 49 and a layer of phase change material 50. The layer of thermal insulation 49 is provided by a self-supporting layer of foam insulation, for example having a thickness between 3 mm and 15 mm; the layer of phase change material 50 is preferably provided as a flexible, leak-free flexible sheet in which a phase change material is incorporated. A thermally insulating envelope 51, for example comprising PIR foam, is provided in the base 41 of the vaccine storage container 40 so as to surround the product storage compartment 42 and the ice-pack compartments 46. The thermally insulation envelope 47 may also comprises vaccine insulation panels 52, notably positioned adjacent to the ice-pack compartments 46 and adjacent to the base 42a of the vaccine storage compartment so as to provide an highly insulating inner lining of the thermally insulating envelope. The lid 43 of the vaccine storage container 40 is also provided with thermal insulation 43a, for example of PIR foam.

[0041] FIGS. 5a, 5b and 5c illustrate an alternative passive vaccine storage container 40 in which the vaccine storage compartment 42 is defined by a liner 44 having an inner sleeve 44a assembled with an outer sleeve 44b with a cavity 44c arranged between the inner 44a and outer 44b sleeves housing a thermal barrier comprising a sheet of phase change material 50 of the type as described in relation to FIGS. 4a and 4b.

LIST OF REFERENCES

[0042] 10 test apparatus [0043] 11 product storage compartment [0044] 12 sleeve [0045] 13 temperature sensor support plate [0046] 14 ice-pack [0047] 15 ice-pack [0048] 16 ice-pack [0049] 17 ice-pack [0050] 18 insulating foam plates [0051] 21 temperature sensor [0052] 22 temperature sensor [0053] 23 temperature sensor [0054] 24 temperature sensor [0055] 25 temperature sensor [0056] 26 expanded polypropylene insulation [0057] 27 expanded polypropylene insulation [0058] 28 phase change material [0059] 29 phase change material [0060] 30 aluminium plate [0061] 40 passive vaccine storage container; [0062] 41 base [0063] 42 vaccine storage compartment; [0064] 42a base of vaccine storage compartment [0065] 42b sidewalls vaccine storage compartment [0066] 42c vaccine compartment lid [0067] 43 lid of vaccine storage container [0068] 43a thermal insulation of lid [0069] 44 liner or cage [0070] 44a inner sleeve of liner [0071] 44b outer sleeve of liner [0072] 44c cavity [0073] 45 ice-pack [0074] 46 ice-pack compartment [0075] 47 thermal barrier [0076] 48 temperature distribution element [0077] 49 thermal insulation [0078] 50 phase change material [0079] 51 thermally insulating envelope [0080] 52 vaccine insulation panels