GB2556358A - A passive temperature control system for transport and storage containers - Google Patents

Abstract

A temperature controlled transport or storage container 30 suitable for transporting or storing temperature sensitive materials comprising: an outer insulating container having a top wall, bottom inner wall and inner sidewalls, insulating means comprising a lining disposed adjacent said inner walls, a plurality of temperature control packs 20 wherein said temperature control packs 20 include first and second phase change materials and said first and second phase change materials (PCM) are placed within the temperature control pack adjacent and co-planer one another. The temperature control packs may comprise a further phase change material (PCM), wherein the first and second PCMs may have a phase change temperature between +25°C to -20°C and the temperature control packs may include each group of PCMs in equal numbers. The PCMs may be thermally connected to each other via a thermally conductive layer (fig.1a) coated with a reflective coating such as an aluminised coating and for each side of the container there may be only one temperature control pack which retains a single PCM.

Description

(54) Title of the Invention: A passive temperature control system for transport and storage containers Abstract Title: A PASSIVE TEMPERATURE CONTROL SYSTEM FOR TRANSPORT AND STORAGE CONTAINERS (57) A temperature controlled transport or storage container 30 suitable for transporting or storing temperature sensitive materials comprising: an outer insulating container having a top wall, bottom inner wall and inner sidewalls, insulating means comprising a lining disposed adjacent said inner walls, a plurality of temperature control packs 20 wherein said temperature control packs 20 include first and second phase change materials and said first and second phase change materials (PCM) are placed within the temperature control pack adjacent and co-planer one another. The temperature control packs may comprise a further phase change material (PCM), wherein the first and second PCMs may have a phase change temperature between +25°C to -20°C and the temperature control packs may include each group of PCMs in equal numbers. The PCMs may be thermally connected to each other via a thermally conductive layer (fig. 1a) coated with a reflective coating such as an aluminised coating and for each side of the container there may be only one temperature control pack which retains a single PCM.

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A PASSIVE TEMPERATURE CONTROL SYSTEM FOR TRANSPORT AND STORAGE CONTAINERS

Field of Invention [0001] The present invention relates to the field of the transportation and storage of goods and to a passive temperature control system for such a transport and storage containers.

Background to the Invention [0002] In the field of logistics, that is the field of movement and supply of produce and materials, there is a substantial requirement for the provision of a temperature control system to ensure that certain types of produce and materials do not pass through temperature thresholds. It is well known that, for example, vegetables when subject to extremes of temperature that they become flaccid, as the cell structure is broken down through the formation of icicles or through dehydration. Similarly, in the transport of drugs and vaccines and certain other chemicals, a solution may separate or become solid. It will also be appreciated that even relatively small amounts of pharmaceutical product can cost thousands of pounds or more; temperature deviations from an allowed temperature can become very expensive; such goods typically having journey temperature plotting indicators, whereby any temperature deviation means that product is discarded and destroyed, irrespective of the cost of the product.

[0003] In essence, in any transport container with a thermally sensitive load, the rate at which heat passes through the packaging material of the transport container - the amount of heat that flows per unit time through a unit area with a temperature gradient per unit distance must not extend beyond a permitted temperature range for the product. Temperature control of thermally sensitive goods is particularly challenging when the thermally sensitive goods must be maintained within a narrow temperature range.

[0004] Multilayer insulation (MLI) is the most common passive thermal control element used in transport. MLI seeks to prevent both heat losses to the environment and excessive heating from the environment. Low cost temperature control in the transport industry relies upon MLI to retain an inside temperature subject to the thermal path to a transported product from an outside the outside to maintain ideal operating temperature. MLI can simply comprise layers of plastics foam; more complex MLI can consist of an outer cover layer, an interior layer, and an inner cover layer. Some common materials used to the outer layer are fiberglass woven cloth impregnated with PTFE Teflon, PVF reinforced with

Nomex bonded with polyester adhesive, and FEP Teflon. The general requirement for interior layer is that it needs to have a low emittance. The most commonly used material for this layer is Mylar that is aluminized on both or one side. The interiors layers can be thin compared to the outer layer to save weight.

[0005] It has been known to store goods which are sensitive to temperature in thermally insulated containers in which so-called cooling blocks are housed. One simple example of such a container is that used by homemakers to store food. In this case, the interior of the thermal container need only be kept cool for a relatively short period of time. Because of this, and because direct contact of the food with the cooling block is not normally harmful, it suffices to freeze the block to the necessary temperature prior to using the same. In their simplest form, the cooling blocks are filled solely with water, which when frozen has a high heat of fusion and consequently is able to maintain the food in a cool environment for a considerably period of time. Such an apparatus is effective to keep food wholesome or to keep beverages cool for a certain period of time at ambient temperatures which lie above the desired storage temperatures. The use of cooling blocks filled with water cannot be considered for the storage of freezesensitive products, such as blood within tolerable temperature ranges, particularly in the case when the ambient temperature falls beneath a permitted storage temperature, since the latent heat of fusion of water on the formation of ice is not released until the temperature falls below 0°C, meaning that a product could be cooled below an ideal temperature.

[0006] Typical means for shipping temperature sensitive materials involves the use of an insulated box, with the necessary shipping and warning labels, along with some cooling agent. These cooling agents have typically been, for example, a frozen gel, dry ice, or wet ice, placed within an insulator packing agent, such as cotton or, latterly, plastics materials such as expanded polystyrene foam, wherein heat is absorbed by such cooling agents.

[0007] There are, however, several problems with the conventional approach. First, the polystyrene foam used for insulation does not degrade readily, leading to disposal problems. Second, the cooling agents also present numerous practical problems in field use. Specifically, gel systems are often too expensive for routine use and disposal. As for dry ice, the carbon dioxide gas evolved during shipment is so dangerous to shipping personnel that hazard warnings must be posted and additional fees are required to be paid; furthermore, outright bans on dry ice are pending in several areas. Finally, wet ice poses handling problems in packing, as well as leakage and product soaking problems.

[0008] Blood, meaning transfusion blood, must be maintained within a close temperature range of between +1°C and +6°C during its passage between donor and receiver. Various biological products, such as platelets, whole blood, semen, organs and tissue, must be maintained above a predetermined minimum temperature and below a predetermined maximum temperature. Pharmaceutical products are also commonly required to be kept within a specified temperature range. Food products, flowers and produce frequently have preferred storage temperature ranges as well. Indeed, certain types of goods have stringent standards to be adhered to. For example, as part of a World Health Organisation (WHO) prequalification scheme, vaccine manufacturers are expected to ensure their packaging complies with the criteria specified below: Class A packaging: Vaccines must be packed to ensure that the warmest temperature inside the insulated package does not rise above +8°C in continuous external ambient temperatures of +43°C for a period of at least 48 hours. Class B packaging: Vaccines must be packed to ensure that the warmest temperature inside the insulated package does not rise above +30°C in continuous external ambient temperatures of +43°C for a period of at least 48 hours. Class C packaging: Vaccines must be packed to ensure that the warmest temperature inside the insulated package does not rise above +30°C in continuous external ambient temperatures of +43°C for a period of at least 48 hours and the coolest storage temperature of the vaccine does not fall below +2°C in continuous external temperatures of -5°C for a period of at least 48 hours. Many known methods and systems for shipping such products are not able to keep temperatures within the desired range.

[0009] Numerous insulated shipping containers have been developed over the years, with those deploying a phase change material (PCM) generally providing superior temperature control over extended periods. Insulated shipping containers employing a PCM can be deployed for a wide range of thermally sensitive goods over a wide range of target temperatures by using different PCMs. For example, D2O melts at +4°C, H2O melts at 0°C, a 20% ethylene glycol solution melts at -8°C, castor oil melts at -10°C, neat ethylene glycol melts at 12.9°C, mineral oil melts at -30°C, and a 50% ethylene glycol solution melts at 37°C. This permits use of insulated shipping containers for a broad range of thermally labile goods. However, in order to accommodate the packaging of a wide variety of thermally labile goods, the shipper needs to purchase and inventory a sufficient number of PCM panels containing each of the different PCMs to meet the highest possible demand for that type of PCM panel. For example, assume that a shipper typically has between about 800 and 1,200 passive thermally regulated shipping containers in transport on any given day, each of which employ six PCM panels and all of which could require one of two different PCM panels containing different PCM. This shipper would need to purchase, inventory, track and maintain 14,400 PCM panels ((1,200 containers)(6 PCM panels/container)(2 PCM panel types)). The need to purchase, track and maintain such a large number of PCM panels can become cost prohibitive.

[0010] Current design practice in temperature controlled packaging involves using a single temperature PCM conditioned in an 'ideal' state depending on the thermal challenge to be presented to the temperature controlled packaging during shipment. However this is troublesome on two counts. Firstly, the PCM packs must be warmed or cooled to just above or just below their Phase Change Point, this can be difficult to achieve in normal industrial warehousing scenarios, as such ideal temperature ranges can be as narrow as (for hot shipping conditions) +15°C to +19°C and (for cold shipping conditions) +20°C to +24°C. Secondly, it is very hard to predict what conditions will be experienced by the TCP during transit.

[0011] In order to maintain a stable temperature it is advantageous to use a Phase Change Material (PCM) that has a Latent Heat of Fusion both above and below the standard hold temperature of +20°C (the mid-point of most pharmaceutical specification warehouses), but this is difficult to achieve with the use of just one PCM. Indeed, the use of two PCMs within a shipping container is known. In US7908870 to Entropy Solutions and US8424335 to Pelican, arrangements that utilise Dual PCM embodiments are taught having a thermal insulation and a plurality of different phase change materials within an interior volume. Specifically, these documents relate to a container and a plurality of different phase change materials within an interior volume, to provide respectively - and with reference to Figures la and lb, to a container having exterior thermal insulation lal, a first phase change material PCM1 (for example water), a further layer of insulation la2, a second layer of phase change material PCM2, and to a container having exterior thermal insulation lbl, a first phase change material PCM1 (for example water), a second layer of phase change material PCM2 (for example paraffin wax), wherein at least one of the PCMs acts as a thermal buffer to protect a temperature sensitive payload against thermal damage from the other PCM having a temperature outside of a predetermined temperature range for payload protection. Each container will be adapted in size / temperature combination to determine a thermally controlled container in respect of a particular payload, target temperature, guaranteed duration of thermal control, size of and weight of container.

[0013] Whilst these systems are stated as working within limited temperature ranges, for periods of time they can be difficult to set up with different temperature profiles to be achieved. Specifically, where two phase change materials are employed, these materials have been selected, temperature conditioned, stored and packed separately, in a correct, predetermined fashion to provide the optimal thermal protection. It has been known that the phase change materials have been confused and misplaced in a container upon loading of the container, giving rise to an incorrect temperature-time profile; equally, supervisory actions and checking operations become necessary, leading to increase in loading time i.e. provides an additional delay and incur further processing costs. Essentially, such known systems either cannot provide broad range of temperature thresholds or are complicated to set up and as a result are liable to failure.

Object of the Invention [0014] The present invention seeks to provide a solution to the problems addressed above. The present invention seeks to provide a phase change material system that can enable goods to reliably be maintained within a particular temperature range. The present invention also seeks to provide a temperature controlled transport/storage assembly for goods palletised or otherwise, whereby goods can be maintained within an atmosphere having a predefined temperature range.

Statement of Invention [0015] In accordance with a general aspect of the invention, there is provided a temperature controlled transport/storage container for transporting/storing temperature sensitive materials comprising: an outer insulating container having a top inner wall, a bottom inner wall and inner sidewalls; insulating means for insulating said cavity comprised of a lining disposed adjacent said inner walls of said carton to define an insulated cavity; a plurality of temperature control packs for placement within said insulated cavity, adjacent said means for lining said inner walls to define a payload volume; wherein said temperature control packs include first and second phase change materials, wherein the phase change materials are arranged as generally planar packages, each planar package having spaced apart first and second major planes, each type of phase change material providing distinct thermal characteristics, the first major faces of the phase change materials being arranged in a co-planar fashion whereby at least two types of phase change material package face the payload volume.

[0016] In use, the temperature control packs are configured for a particular period of time, with reference to the type of load, volume of load, and expected ambient temperatures likely to be encountered. By configuring the different types of phase change material in a co-planar fashion, it will be appreciated that an effective load volume is increased significantly. This is because the increase in effective transport volume is greater than a nominal reduction in thickness per insulation layer and phase change materials per given it may well be effective in three dimensions, given that previous practice of providing such temperature control elements in has been to provide such distinct phase control elements in distinct layers. Conveniently, said temperature control packs are contained within an envelope comprising a generally rectangular box shape, made from an insulating sheet material such as cardboard, or a plastics, in the form of a simple sheet or corrugated, whereby to define a separation distance.

[0017] Conveniently, said temperature control packs which include first and second phase change materials, are contained in sealed containers and said containers are arranged as a unitary element by virtue of being associated with each other. For example, the pack can be defined by one of a cardboard or plastics sheet box or sleeve the sheet material being a plain sheet or optionally corrugated, plastics bag, a blister pack, a sheet cellulose package, a sealed polymer enclosure. Additional insulation could be provided on an outside surface of the pack, although this could have an effect in increasing a conditioning period of time in a temperature controlled enclosure, before use, as is known. Ideally, through the common use of a standard sized package, inventory levels can be simplified.

[0018] The temperature control packs can be configured to provide a thermally stable atmosphere within the payload volume for a number of days as is typical for international travel, for example. The present invention can, by the use of specially adapted thermal modelling software, be optimised for particular goods for specific transport and storage time with respect to a specific payload space. If the size and number of product cartons is known that need to be shipped, an analysis can be simply be performed whereby to provide users with graphical and statistical results to ensure cost effective use of the present invention in a packaging system. By maximising the available useful product volume, it will be appreciated that the overall package employed can be smaller than what otherwise have been used, with a concomitant benefit in a reduction of transport and storage charges. This has the advantage that a particular temperature sensitive consignment can be tailored for a particular transport scenario.

[0019] The first and second phase change materials could each have a phase change temperature in the range of +50°C to -80°C; conveniently, the phase change materials are conditioned at the same temperature - i.e. once placed within a temperature control pack, whereby overall processes can be simplified. It is possible that the temperature control packs include at least one further phase change material. The temperature control packs can be arranged such that they include equal numbers of particular types of phase change materials. More typically, the first and second phase change materials would have a phase change temperature in the range of +250°C to -20°C. Such a range of phase change materials can cater for most typical temperature controlled storage and transport requirements. Typically, however the first and second phase change materials which define the upper and lower phase change temperatures have a difference of 6-10 °C. This is such that in the case of vegetables, for example, transport conditions are typically between 4°C and 12°C; with reference to, say, lettuce, if the temperature goes below freezing point, water within the cell structure present will become ice and the ice crystals will destroy the leaf structure; equally, having the products at extended periods above 12°C will result in the water within the cell structure evaporating.

[0020] The phase change materials can be contained in the form of one or more of flexible plastics bags; flexible polymer bags; flexible blister packs; putty; foam encapsulation. The phase change materials could also be presented in a moulded plastics container, such as a blow-moulded enclosure such as high density polyethylene plastics material or similar. Conveniently, the packaging system, together with such phase change materials, is presented in a container such as a cardboard box or sleeve. The phase change materials can be thermally connected with each other via a thermally conductive layer of material, which could be applied to the container, and could comprise a reflective coating such as an aluminized coating. Alternatively, the container is manufactured from plastics sheeting, corrugated cardboard and corrugated plastics. The insulating means for insulating said cavity could comprise one of or more of: a plastics foam; cellulose fibre (loose); cellulose fibre (compressed); Multilayer insulation (MLI) including plastics foam; fibreglass woven cloth; fibreglass woven cloth impregnated with PTFE Teflon, PVF reinforced with Nomex bonded with polyester adhesive, and FEP Teflon, Mylar that is aluminized on both or one side. Given that certain packaging systems comprise small cartons which such cartons are often transported together, it has been found that when grouped, en masse, this has had a negligible effect. In an alternative system, the present invention provides a packaging system, wherein the box has a number of sides and for each side of there is a phase change material temperature control pack. Notwithstanding this each phase change material temperature control pack is provided with dual / multiple phase change materials.

[0021] In a further aspect of the invention, the phase change materials can be disposed in separate interlocking moulded elements, with for example, a first, peripheral resilient moulded container operably filed with a first phase change material in the general shape of an oval, with a central aperture defining a cavity, with a second, central resilient moulded container operably filed with a second phase change material, whereby to provide a unitary temperature control element, optionally provided with an insulation layer, whereby to be placed adjacent product, without a further, separate layer of insulation, to thereby still further maximise an internal volume but also enabling a simplifying the associated packing process.

[0022] In accordance with another aspect of the invention, there is provided a method of packing a container for shipment comprising the steps of

a. obtaining a container;

b. lining the entire interior surface of the container with insulator material;

c. selecting a plurality of temperature control packs for placement within said insulated cavity, wherein said temperature control packs include at least first and second phase change materials arranged as generally planar packages, each planar package having spaced apart first and second major planes with edge faces connecting the first and second major planes; wherein the phase change materials provides distinct thermal characteristics, wherein the at least two types of phase change material packages are arranged in a coplanar orientation with respect to each other;

d. determining a temperature at which to condition a temperature control pack means with regard to the size of the container, the duration of transport/storage of the container; expected ambient conditions;

e. placing the temperature control pack at the determined temperature in a temperature conditioning apparatus, whereby to ensure the temperature control pack is brought to said set temperature;

f. placing the temperature control packs having been brought to said set temperature in the container whereby to define a payload volume;

g. placing a payload within the payload volume;

h. placing a temperature control pack upon the payload and other temperature control means; and,

i. closing and sealing the container.

It will be appreciated that separate layers of insulation may need to be provided.

[0023] The present invention can thus provide a simple to use solution, conveniently using only one type of phase change material wallet for a particular container system, thereby reducing the chance of failure through the incorrect orientation / placement of one of two types of phase change material. Whilst possible, one could temperature condition the two types of phase change material separately; this would not ordinarily be beneficial - by correct selection of the two phase change materials, placement of the phase change material containers within the wallet provides a convenient and method simplifying a loading process. Additionally, the use of two phase change materials arranged in co-planar fashion as opposed to being arranged in a thicker, spaced apart in a parallel fashion can reduce wastage within a container, meaning that more goods for a given unit volume can be employed or a smaller box can be selected. Additionally, a substantial benefit is that all the temperature conditioning of the phase change materials occurs with respect to one fridge/cool room prior to placement within a container for transport / storage of temperature sensitive goods, where the sleeves are either highly insulating in themselves or benefit from further internal and or external thermally insulating media comprising panels, sleeves or other insulating materials. Additionally, in one embodiment, the invention also benefits from its ability to use the same size temperature control packs to be utilised in different containers; commonality of parts between ranges of product can provide more cost-effective construction and/or different functionality.

Brief Description of the Figures [0024] For a better understanding ofthe present invention, reference will now be made, by way of example only, to the Figures as shown in the accompanying drawing sheets, wherein:Figures la, lb illustrate sections through two known temperature control configurations from an inside wall of a container through to a payload;

Figure 2a, 2b illustrate first and second perspective views of a phase change cassette;

Figure 2c, 2d show two different orientations of phase change packets with a phase change cassette;

Figure 3a shows a view of a container in accordance with the invention prior to placement of the insulating material cover and cassettes of phase change material with respect to a load;

Figure 3b shows an arrangement of phase change plastics bags within a phase change cassette;

Figure 3c shows a sections through a temperature control configuration in accordance with another embodiment of the invention from an inside wall of a container through to a payload;

Figure 3d shows a plan view of a phase change cassette in accordance with the embodiment shown in Figure 3c;

Figure 4 shows a typical non-integrated pallet with a load;

Figures 5a and 5b show a first component in accordance with one aspect of the invention in perspective view and the temperature - phase characteristic of the two types of phase change material;

Figure 6 shows an exploded view of a container in accordance with the invention indicating the placement of cassettes of phase change material with respect to a load;

Figures 6a and 6b comprise graphs comparing temperature change over time in packaging in accordance with the inventions at with respect to typical external ambient temperatures, as encountered during travel;

Figures 6c and 6d comprise graphs detailing the temperature change over time in packaging in accordance with the inventions at constant specific external ambient temperatures;

Figures 7a - 7c show how modular PCM strips can be configured;

Figures 8a - 8d show the manufacturing steps in manufacturing PCM modules;

Figures 9a - 9c detail a still further embodiment of a PCM module; and,

Figure 9d shows a still further embodiment of a PCM arrangement.

Detailed description of the Preferred Embodiments [0025] There will now be described, by way of example only, the best mode contemplated by the inventor for carrying out the present invention. In the following description, numerous specific details are set out in order to provide a complete understanding to the present invention. It will be apparent to those skilled in the art, that the present invention may be put into practice with variations of the specific.

[0026] With reference to Figure 2, an aspect of one embodiment in accordance with the present invention shall be described in a simple to use assembly comprising a cardboard wallet (aka cassette I envelope I sleeve) 20 in which a number of first 21 and second 22 plastics bags are placed containing, respectively, first and second phase change materials are placed. The wallet may also be represented as a sleeve. Conveniently, there are four elements placed therein or - alternatively - eight elements placed therein in two layers. Other configurations are possible; simplicity is, nonetheless, of benefit. This embodiment of the invention utilises plastic bags 21, 22 filled with different phase change materials (PCM), to maintain the internal product temperature between +15° to +25°, which temperature is also known as the Control Room Temperature (CRT). Figure 2c shows the separate phase change materials placed in parallel spaced apart relationship; in Figure 2d, the phase change materials are spaced diagonally with respect to each other. Especially with the use of a conductive film interface in contact with the plastics bags, such difference in packaging has not realised a significant difference in internal temperatures measured.

[0027] Such wallets are conveniently dimensioned to be placed with a suitably tight fit within a container 30 as shown in Figure 3a but a typical cassette will have dimensions of 300 x 250 x 25 mm. Figure 3b shows an arrangement of first and second phase change materials as contained within plastics bags, as can conveniently be simply manufactured using standard bag filling techniques. Figure 3c shows a similar cassette, save that the phase change materials are contained within plastics trays (as shall be discussed below), with the cassette being shown in cross-section vis-a-vis a load and wallet/cassette 20. This figure can be compared to the cross-sectional views shown in relation to the prior art in Figures la and lb. Whilst, the present invention may well have a first and second insulation layers, it can be readily understood, the a layer of phase change material has been removed, whereby to make the packing of shipping (or storage) containers simpler and, importantly, less liable to incorrect packing, by for example, a reversal of the order of the first and second coolant wallets 20. A significant effect is that the effective payload area for a given volume is increased, given that the prior art perception of a requirement of separation of distinct phase control materials is not, in actual fact, required.

[0028] Figure 3d shows a plan view of a coolant wallet with the two different phase change materials, PCM1 & PCM2, having phase change temperatures as indicated (+17°C and +22°C). A main advantage of the concept behind the present invention is that a single temperature control wallet is placed within a container having been temperature conditioned at a single temperature, the types of phase change materials, the respective amounts of the different phase change materials and the conditioning temperature being selected dependent upon the anticipated temperatures, the desired internal temperature and the nature of the filling, taking into account the nature of the packing container and associated insulation surrounding the temperature control wallets.

[0029] In a first variation, there can be further provided a layer of material having a high thermal conductivity in contact with the plastic bags containing the phase change material, to enable the creation of a surface having a substantially homogenous temperature within the wallet, which material is preferably associated with the face adjacent the payload space. In particular, the thermally conductive layer can conveniently be positioned between the plastics bags of phase change material and the face of the cassette that would face the payload area. Materials such as metallized film adhered to a carrier paper or a metallized film applied to a rigid plastics sheet and associated with corrugated board can be conveniently provided. Such a material could also form part of the wallet body.

[0030] The present invention enables phase change materials about a payload to absorb heat I release energy to resist cold by enabling a phase change material to react with respect to changes in external temperatures, where the phase change materials are selected to define a selected permissible range of temperatures within a payload area of the container. As will be appreciated, as the container enters a reduced temperature zone, the phase change materials will release energy due, at least in part, to a change in phase of a lower temperature rated phase change material. Equally, as the container enters an elevated temperature zone, the phase change materials will absorb energy due, at least in part, to a change in phase of a higher temperature rated phase change material. That is to say, each phase change material will change state from liquid to solid to release energy or will change state from solid to liquid, to absorb energy. As will be appreciated, in a change of phase state, a material will remain at substantially the same temperature; i.e. the temperature of the material remains stable, as can be seen in the graph shown in Figure 4. It is important to realise that in a freezing phase, energy is released in an exothermic process; whilst in a melting phase, energy is absorbed by the phase change material in an endothermic reaction.

[0031] With reference to Figures 5a and 5b, there is shown an example of a temperature control wallet comprising two types of phase change material. This dual PCM system, for example, allows for the two phase change materials to be stored at +20°C and achieve a composite of solid I liquid segments within the temperature control wallet. The overall thermal effectiveness of the pack permits protection of the temperature sensitive goods to be achieved with a single conditioning temperature of, for example +20°C. Specifically, and as has been tested in respect of the present invention, a combination of a +17°C PCM and a +22°C PCM, when placed in a wallet can be simply considered at 20°C as comprising a first liquid phase change material (i.e. the +17°C PCM), offering maximum thermal protection against cold thermal stress on the system and a second solid phase change material (i.e. the +22°C PCM), offering maximum thermal protection against thermal stress on the system. Applicants have determined that by the placement of these distinct phase change materials within the same container (wallet, cassette, etc.) then the overall temperature balancing effect can be retained, without the previously determined requirement to have separate containers in respect of the separate phase change materials. It has been found that the provision of a layer of material having a high thermal conductivity in contact with the phase change materials plastics bags to allow a homogenous temperature to be created on the contact face (lowermost face) of the assembly - where it would contact the payload space in the temperature controlled package.

[0032] Current design practice in temperature controlled package involves:

i) in the case of the use of a single phase change material, then this phase change materials is conditioned in an 'ideal' state depending on the likely thermal challenge to be presented to the temperature controlled package during shipment. However this is troublesome on two counts, namely that the phase change packs must be warmed or cooled to just above or just below their determined phase change temperature, which can be difficult to achieve in normal industrial warehousing scenarios, as such ideal temperature ranges can be as narrow as (for hot shipping conditions) +15°C to +19°C and (for cold shipping conditions) +20°C to +24°C and; it is very hard to predict what conditions will be experienced by the temperature controlled package during transit.

ii) When two phase change materials are employed, the distinct phase change materials are contained/packaged/installed as two distinct components. It will be noted that these distinct components need to be selected, labelled, conditioned and placed in distinct these components have to be stored at the correct temperature and must be packed in the correct manner to provide the optimal thermal protection.

[0033] The present invention thus allows for a simple, single temperature preparation of the dual phase change containers/cassettes at standard Control Room Temperature (CRT) conditions. The design requires little training to facilitate use which will safeguard quality of shipment. Importantly the margin for error is significantly reduced. In use, the temperature of the phase change materials is calculated to enable the temperature to be centred about an ideal temperature depending on the thermal challenge to be presented to the temperature controlled package during shipment. However this is troublesome on two counts:

[0034] The phase change materials plastics bags that are filled with two different PCMs that have different Freeze/Thaw temperatures. With reference to the embodiments in Figures 5a - 7c:

[0035] PCM1 has a Freeze/Thaw temperature at around +17°C, that at +20°C would be in a liquid state and would temperature stabilise at +17°C as it freezes if the TCP was exposed to temperatures less than +17°C. There is a capability to tailor the amount of phase change material in the cassettes whereby the overall thermal response characteristics can be adjusted depending on the thermal challenge anticipated.

[0036] PCM2 has a Freeze/Thaw temperature at around +22°C, that at +20°C would be in a solid state and would temperature stabilise at +22°C as it thaws if the TCP was exposed to temperatures greater than +22°C.

Embodiment #1 - Adjacent - in line [0037] This embodiment has the two phase change materials in separate plastics bags in-line with each other, packed into the same cardboard container or cassette. It has been found that the provision of a layer of material having a high thermal conductivity in contact with the phase change materials plastics bags to allow a homogenous temperature to be created on the contact face (lowermost face) of the assembly - where it would contact the payload space in the temperature controlled package.

Embodiment #2 - Adjacent - alternating [0038] This embodiment has the two phase change materials in separate plastics bags alternating with each other, packed into the cardboard container or cassette. This design is believed, in principle, to provide greater thermal stability than the first embodiment due to the better spread of the differing latent heat materials, but this might not be noticeable in practice. It has been found that the provision of a layer of material having a high thermal conductivity in contact with the phase change materials plastics bags to allow a homogenous temperature to be created on the contact face (lowermost face) of the assembly - where it would contact the payload space in the temperature controlled package.

[0039] To enable a simple appraisal of the thermal capability of the present invention, extensive thermal testing has been performed, with reference the results of which show a distinct advantage of the Dual Adjacent PCM system of a system with only one or the other PCM contained within. Specifically, with reference to Figure 6, which shows a container with external insulating panels outside of the PCM panels, in first and second series of tests under, respectively, summer and winter conditions, the three systems being tested, as follows:

Si) The use of a single type of PCM material only - +17PCM - which provided poor HOT protection as no phase change occurs since such a phase change material is liquid at +20°C.

Sii) The use of a single type of PCM material only - +22 PCM - which provided good HOT protection as phase change occurs at +22°C.

Siii) The use of two types of phase change materials -+17 and +22 PCM materials - which provided good HOT protection as phase change occurs at +22°C

- for the +22PCM material.

Wi) The use of a single type of PCM material only - +17PCM - which provided good cold protection as phase change occurs since such a phase change material has a phase transition temperature of +17°C.

Wii) The use of a single type of phase change material only - +22 PCM - which provided poor cold protection as phase change occurs at +22°C.

Wiii) The use of two types of phase change materials -+17 and +22 PCM materials - which provided good cold protection as phase change occurs at +17°C

- for the +17PCM material.

[0040] The results of the first and second tests are shown with reference to Figures 6a and 6b and it is clear to see that the system using the two phase change material embodiment out performs the systems that only utilise one phase change material type, which is common in the TCP market place today.

[0041] In a further set of tests, a prototype system using the same +17 and +22PCM materials - changing phases, respectively at +17°C and +22°C. The system was prepared with all the phase change materials conditioned at +20°C and then tested at two ambient stresses, namely a constant +30°C (equivalent to many ambient summer conditions) and a constant +5°C (equivalent to many ambient winter conditions). The results of these tests are graphically shown in Figures 6c and 6d, respectively, where it is shown that: under summer conditions a payload temperature was maintained payload between +15°C to +25°C for 38hrs; and under winter conditions a payload temperature was maintained between +15°C to +25°C for 68hrs. It will be appreciated that the ratio of +17 to +22 phase change materials can be altered to help 'balance' the performance levels achieved against the hot and cold stress test profiles. Equally different types of phase change material could be employed.

[0042] Applicants have also developed a process of manufacturing phase change materials wherein phase change materials, in liquid form, can be placed in trays defined in multi-layer thermo-formed plastics films. Plastics such as Acrylonitrilebutadiene-styrene (ABS) and acrylic can also be used to prove relatively rigid assemblies, which can be of benefit. Pre-set phase change material ratios can be adapted for particular circumstances and are placed in respective trays, the material conveniently being placed whilst in a liquid state under low atmospheric pressure and sealed with a plastics film which is used to seal under the application of heat and/or an adhesive. This plastics film could also be conductive, as discussed above.

[0043] Further types of phase change materials are being continuously developed and presently phase change materials are being developed which have putty-like formable handling characteristics at certain temperatures, whereby to enable particular shapes to be created. Such shapes can be encased in plastics films to provide phase change materials in something analogous to blister pack pockets. Manufacturing methods for producing blister packs are well-developed. The primary component of a blister pack is a cavity or pocket made from a formable web, usually a thermoformed plastic. This usually has a backing of paperboard or a lidding seal of aluminium foil or plastic. Blister packs are useful for protecting products against external factors, such as humidity and contamination for extended periods of time. Opaque blisters also protect light-sensitive products against UV rays. In a further alternative of the present invention blister packs can be produced with a shape arranged such that only a percentage of cavities of a blister pack in a pattern being employed, with apertures present where unfilled blisters are present; by combining with another blister pack arrangement in respect of a second phase change material, a two dimensional array of two phase change materials could be prepared. Equally, not all the blister centres in a pattern need be occupied. A third or further phase change material could be provided in the gaps that have remained unfilled. Given that a range of phase change materials exist, by the use of colour coding, visible, for example through a small aperture in a cassette or wallet enclosure, a make-up of a cassette can be determined and temperature conditioned prior to use in a simple fashion.

[0044] It should also be noted that the presentation of PCM materials is being continually developed. For example, Microencapsulated phase change material sometimes referred to as microPCM - products are now becoming commonplace. Microencapsulated phase change material products comprise very small dualcomponent entities consisting of a core material comprised of a phase change material PCM - and an outer shell or capsule wall. The PCM substance can conveniently be provided as a wax - such as a paraffin-wax or a fatty acid ester operable to absorb and release energy in the form of heat in order to maintain a particular temperature. In use, in a warm environment with an increasing temperature, the PCM would initially absorb the heat (the PCM melts inside the capsule wall) and store it until the temperature drops from the outside environment; at which time, the heat is released (the PCM re-solidifying within the capsule wall) releasing energy in the form of heat, which can assist in temperature control. At all times, the capsule wall contains the PCM, so regardless of whether the actual PCM is in the liquid or solid state, the capsule itself remains as a solid particle containing the PCM. The capsule wall can conveniently be provided as an inert, very stable polymer. Such PCMs can be provide in a manner of slurry, where, for example a capsule size of 1 - 4pm is employed with 35-45% as solid in an aqueous slurry, a paste, where capsules of a size between 10 and 30pm are present as 70% solids with water or as a dry powder, the micro capsules of 10 - 30pm being processed such that they can be provided with polyurethane foams and the like. Larger beads or capsules, of the order of 2 - 5mm - sometimes referred to as macroPCM capsules can also be employed.

[0045] Thus, by the use of such micro/macroPCM particles, used with PU foam, and other binders stable products of two or more PCM materials can be reliably be produced. PU foam may be considered as having too much insulator gas by volume; accordingly, a binder may be employed such that the particles are compressed and retained without too much dead space, which can also affect the rate of change. It is also to be noted that the micro/macroPCM particles may be filled with one or more types of PCM. Equally, there may be provided two distinct types of micro/macroPCM particle. By the use of organic-based phase change material, the phase change properties are not been observed to lose their efficacy over thousands of cycles.

[0046] With reference to Figures 8a - 8d, an outline process shall now be described: In figure 8a, a base multi-layer film is thermo-formed into 'trays'. Using foam technology, for example, a shape-stable foam is placed into the tray cavities - per Figure 8b. First and second phase control materials are then introduced into the stabilising foam - per Figure 8c, followed by sealing of the cavities by the placement of a thermally conductive web used to seal the cavities closed.

[0047] Figure 9a and 9b show an alternative arrangement in respectively spacedapart perspective and spaced apart edge view. The phase change materials are enclosed within two separate container elements 91 and 92. Container 91, conveniently manufactured from a plastics material such as high density polyethylene and manufactured using well-known blow moulding techniques, comprises a generally piano-rectangular container with inside walls 93 defining an aperture 94 defined in the middle, into which aperture the separate container 92 can be placed therein. Conveniently, by the use of resilient materials of close corresponding dimensions, the container 92 can be resiliently retained within the aperture 94. Container 91 and container 92 will be filed with different phase change materials. The generally piano-rectangular shape of the container 91 can be shaped to provide indentations 95 to assist in manual handling of the container. It will be appreciated that the aperture need not be centrally arranged within the outer container 91. Equally, a further insert container (not shown) could be provided adjacent the first insert container, with the overall peripheral dimensions of the second 92 and further container corresponding with the internal dimensions of aperture 94. Equally, there could be provided first and second apertures 93.

[0048] Figure 9b shows a variant wherein there is also provided a layer of insulating material 96 - in two parts, whereby an additional card boa rd/sheet plastics envelope element is not require to address any requirement for insulation/spacing of temperature control elements from product. Materials such as metallized film, adhered to a carrier paper and, for example, converted into corrugate board is a good option and could even be used as the material used to form the cassette body. Figure 9c shows a perspective view of phase change material container assembly 91, 92 with a single insulation layer 96. Figure 9d shows a still further cassette, with the cardboard cover in outline and with three blow-moulded containers therein, with the containers each filled with one of two types of PCM.

[0049] This method of manufacture can provide several benefits to users, including the opportunity to Fine tune packaging performance by adjusting a volume fill of each container unit of phase change material. A specific cassette could be provided for a particular user /category of use. This benefit could be realised, for example by having instantly available solutions for a particular user, who may wish to have, for example winter and summer configurations, selected on time of year/weather outlook. This would help ensure 'fit for purpose' package design and cost saving for the customer.

[0050] If the packaging were to be only used in extremely cold conditions, then the volume of PCM1 (+17°C) could be increased, and the volume of PCM2 reduced. This could be achieved by following methods:

1) Increase the Z dimension of the Shape Stable Foam.

2) Increase either the X or Y dimension of the Shape Stable Foam.

3) Altering the Volume of phase change material into each body, typical percentage liquid saturation to shape stable foam volume are in the order of 65% to 90%, therefore the foam volume could be dosed according to the performance requirement without altering the geometry.

[0051] This embodiment allows for simple, single temperature preparation of the Dual phase change material packs at standard Control Room Temperature (CRT) conditions. The design requires little training to facilitate use which will safeguard quality of shipment.

[0052] By changing the fill ratio between first and second phase change materials, the thermal capabilities can be 'tuned' to cope with a specific transport/storage requirement. For example, a customer with a travel requirement under very hot conditions could opt to pack the shipper with more 'Heat Protective' phase change material than the 'Cold Protective' phase change material, thus enabling fine tuning of a shipper's capabilities. This coupled with the use of thermal simulation software could be a very useful and powerful combination enabling the very best fit of a customer's needs to the capabilities of the shipping system.

[0053] Indeed, by the use of a configurable system as provided by the present invention, a logistics company could fine tune the exact performance level required for a logistics company to overcome differing thermal challenges, coupled with the use of thermal simulation software whereby to allow logistics companies to make informed, safe and reliable decisions about how best to configure their modular phase change material shippers. For example, by the use of the micro/macro PCM particles, a 'tuned' performance of a particular package can be achieved by the simple expedient of controlling the ratio of PCM1 to PCM2.

[0054] Pharmaceuticals, proteins, biological samples and other temperature sensitive products, including food items, are regularly shipped in containers year round and are subjected to a wide range of temperatures. Though they are shipped in insulated containers and/or climate controlled environments, the temperature stability of the shipping containers can be significantly improved by applying the techniques of the present invention, whereby to provide a simple solution to the maintenance of temperature profiles for the transport and storage of temperature sensitive products.

[0055] The advantages of using phase change materials for temperature controlled packaging are numerous. Phase change materials can easily replace dry ice or gel packs to reduce the size of shipping containers; they can increase the duration of a temperature control period during shipping. A reduction in transportation costs can simply be realised since less space is devoted to cooling systems, when phase change materials are employed. Phase change materials are reusable. Phase change materials assure predictable and stable temperature control. Phase change materials are available to cover a wide range of temperature ranges.

Claims (18)

CLAIMS:

1) A temperature controlled transport/storage container for transporting/storing temperature sensitive materials comprising: an outer insulating container having a top inner wall, a bottom inner wall and inner sidewalls;

insulating means for insulating said cavity comprised of a lining disposed adjacent said inner walls of said carton to define an insulated cavity; a plurality of temperature control packs for placement within said insulated cavity, adjacent said means for lining said inner walls to define a payload volume; wherein said temperature control packs include at least first and second phase change materials, wherein the phase change materials are arranged as generally planar packages, each planar package having spaced apart first and second major planes, each type of phase change material providing distinct thermal characteristics, the first major faces of the packages being arranged in a coplanar fashion.

2) A temperature controlled transport/storage container according to claim 1, wherein said temperature control packs include first and second phase change materials, are contained in sealed containers/packages, said containers being defined by one of a flexible plastics bag or blister pack, a sheet cellulose package, and a moulded sealed polymer enclosure.

3) A temperature controlled transport/storage container according to claim 1 or 2, wherein said temperature control packs comprise an envelope / sleeve comprising a generally rectangular box shape, made from an insulating sheet material, which envelope can assist in maintenance of a relative position of the phase change materials therein.

4) A temperature controlled transport/storage container according to claim 1 or 2, wherein said temperature control packs comprise one of a single unit with two or more containers for the containment of phase change materials or a composite unit of at least two interconnecting containers for the containment of phase change materials.

5) A temperature controlled transport/storage container according to claim 1 - 4, wherein said temperature control packs include at least one further phase change material.

6) A temperature controlled transport/storage container according to any one of claims 1-5, wherein said temperature control packs include each group of phase change materials in equal numbers.

7. A packaging system according to any one of claims 1-6, wherein the first phase change materials have a phase change temperature in the range of +25°C to -20°C.

8. A packaging system according to any one of claims 1 -7, wherein the phase change materials are presented in the form of one or more of plastics bags; polymer bags; blister packs; putty; foam encapsulation micro/macroPCM particles, whether present as a pre-mixed combination of first and second phase change materials or where the first and second phase change materials are maintained in distinct containers placed adjacent one another.

9. A packaging system according to any one of claims 1-8, wherein said phase change materials are presented in a container such as a cardboard box or a plastics pre-form.

10. A packaging system according to claim 9, wherein said phase change materials are thermally connected with each other via a thermally conductive layer of material.

11. A packaging system according to claim 9, wherein the box has a number of sides to a box and for each side of there is a single phase change material temperature control pack.

12. A packaging system according to claim 9, wherein said phase change materials are thermally connected with each other via a thermally conductive layer of material applied to the container.

13. A packaging system according to claim 12, wherein said thermally conductive layer of material comprises a reflective coating such as an aluminized coating.

14. A packaging system according to any one of claims 1 - 13, wherein the container is manufactured form a cardboard, plastics sheeting, corrugated cardboard and corrugated plastics.

15. A packaging system according to any one of claims 1 - 14, wherein said means for insulating said cavity comprises one of or more of: a plastics foam; cellulose fibre (loose); cellulose fibre (compressed); Multilayer insulation (MLI) including plastics foam; fibreglass woven cloth; fibreglass woven cloth impregnated with PTFE Teflon, PVF reinforced with Nomex bonded with polyester adhesive, and FEP Teflon, Mylar that is aluminized on both or one side.

16. A packaging system according to any one of claims 1 - 13, wherein said means wherein said means for insulating said cavity further comprises a reflective coating such as an aluminized coating.

17. A temperature control pack for use in a temperature controlled transport/storage container according to one of claims 1 - 16.

18. A method of packing a container for shipment comprising the steps of

a. obtaining a container;

b. lining the entire interior surface of the container with insulator material,

c. selecting a plurality of temperature control packs for placement within said insulated cavity, wherein said temperature control packs include at least first and second phase change materials arranged as generally planar packages, each planar package having spaced apart first and second major planes with edge faces connecting the first and second major planes; wherein the phase change materials provides distinct thermal characteristics, wherein the at least two types of phase change material packages are arranged in a coplanar orientation with respect to each other;

d. determining a temperature at which to condition a temperature control pack means with regard to the size of the container, the duration of transport/storage ofthe container; expected ambient conditions;

e. placing the temperature control pack at the determined temperature in a temperature conditioning apparatus, whereby to ensure the temperature control pack is brought to said set temperature;

f. placing the temperature control packs having been brought to said set temperature in the container whereby to define a payload volume;

g. placing a payload within the payload volume;

h. placing a temperature control pack upon the payload and other temperature control means; and,

i. closing and sealing the container.

GB1710195.7

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