Cooling element with sub-cooling protection

Abstract

A cooling element for cooling goods to be chilled is proposed, comprising a shell with at least one heat transfer wall for exchanging thermal energy with the goods. The cooling element further comprises at least one fluid space proximate to the heat transfer wall and at least one storage space separated from the fluid space by at least one separating element, wherein the storage space is configured to hold a supply of cooling medium in the solid aggregate state. The separating element is configured to substantially separate the supply of cooling medium in the solid aggregate state from the fluid space and to enable the cooling medium in the liquid aggregate state to pass over from the storage space to the fluid space.

Description

FIELD OF THE INVENTION[0001]The invention relates to a cooling element for cooling goods to be cooled as well as a refrigerated container with a cooling element according to the invention. Furthermore, the invention relates to a method for cooling goods to be cooled using a cooling element according to the invention as well as a method for manufacturing a cooling element. Such cooling elements, refrigerated containers and methods may be used in particular in the field of pharmacy and medicine for the transport of pharmaceutical and / or medical samples. But also other applications are possible.BACKGROUND ART[0002]Cooling elements are used in a large number of fields and applications. As examples, which are, however, not concluding, various sciences such as chemistry and biology as well as medicine and medical engineering are here to be mentioned. Also in pharmacy, such cooling elements are used for example to keep and / or to transport drugs at an optimum temperature. Additionally, ther...

AI Technical Summary

Benefits of technology

[0030]The separating element may in particular be embodied as mechanically flexible. In particular, the separating element may comprise a nonwoven fabric, that is, a fabric which is neither woven nor knitted, in particular a plastic nonwoven fabric. In particular, the plastic nonwoven fabric may be a plastic nonwoven fabric made of extruded material with short-chain and long-chain portions and an amorphous structure. Nonwovens, in particular porous nonwovens, have proved to be well thermally insulating and may be optimally adapted to the required properties (for example a low wetting and / or uptake of the coolant) at the same time. In particular, the cooling element may comprise one or several layers of a flexible insulating layer, for example a flexible nonwoven. Furthermore, alternatively or additionally, extruded thermally insulating plastics, in particular polyethylenes, polystyrenes, polypropylenes, polyamides or other plastics or mixed plastics, may be used. Such extruded plastics, for example again plastic nonwovens, have particularly favourable properties as they are thermally insulating on the one hand and have a low proportion of air inclusions, which might reduce the above-described basic effect of the invention, on the other hand. Alternatively or additionally, the at least one separating element may also comprise one or several insulating elements, for example one or several evacuated supporting plates or insulating elements with gaseous insulation media. By adapting the materials and / or the embodiments of the separating element, for example the insulation capacity of the separating element, that is the thermal insulation of the storing space against the fluid space and / or against the cooling medium, may be influenced to a large extent. When using insulating nonwovens, this may for example take place in a simple way by choosing the number of layers of the nonwoven fabric.

[0031]As set forth above, the separating element my have in particular thermally insulating properties to reduce or limit a direct heat transfer from the coolant in the solid state of matter in the storing space towards the goods to be cooled. Accordingly, it is particularly preferred if the separating element has a thermal conductivity from 0.01 W / (m*K) to 0.5 W / (m*K), particularly preferably in the range of 0.035 W / (m*K). For example, the separating element may contain for this purpose one or several appropriate insulating materials which produce the above-mentioned thermal conductivities alone or in combination. Alternatively or additionally, it is preferred if the separating element has a thermal resistance of at least 0.05 m2K / W. Also for this purpose, one or several appropriate insulating materials and / or insulating media (such as gas-filled and / or evacuated plates), which produce the above-mentioned properties alone or in their combination, may be provided.

[0032]A further preferred embodiment of the invention is in that the separating element should take up a smallest possible proportion of the coolant in liquid and / or solid state. Such further development has the advantage that, when sub-cooling, the separating element takes up no or only an extremely small proportion of the coolant in solid state, which might then get into closer thermal contact with the goods to be cooled. Thus, many cooling elements are for example kept at room temperature to be then only sub-cooled prior to use. If the separating element had a great absorbing capacity for the liquid coolant, it would for example be already impregnated with the coolant prior to sub-cooling, which would then freeze within such separating element. In order to avoid this, it is particularly preferred if the separating element is embodied in such way that it is able to take up a maximum coolant proportion of 1%, preferably even less, for example a maximum of 0.2%.

[0033]Thus, the coolant may for example be a polar coolant or have at least one polar coolant component, the separating element having in this case preferably at least in sections hydrophobic properties. Thus, for example water may be used as a coolant, for example in combination with a hydrophobic nonwoven as separating element, so that a low uptake of the coolant in the nonwoven is ensured. However, in some cases it would also be obvious to use a non-polar coolant or at least a non-polar coolant component. In this case, it is preferred if the separating element has at least in sections hydrophilic properties.

[0034]The coolant may be embodied in different ways and may in particular, as described below, be adapted to the goods to be cooled. Generally, the coolant is to be a material with a suitable melting point and / or melting range, which is preferably arranged to take up latent heat during melting. Individual coolants or coolant mixtures may be used. In particular, the melting point and / or the melting range may be adapted to a large extent to optimum temperatures of the goods to be cooled. The coolant may have in particular water or alcohol as a polar component. Alternatively or additionally, the coolant may also comprise non-polar components, for example oils, fats, paraffins or similar non-polar liquids. While polar liquids are in particular used in a range up to 0° C., non-polar liquids may be used for example as coolants in the range of positive temperatures, in particular in the range of positive temperatures below room temperature.

[0035]Furthermore, the properties of the coolant may be influenced by one or several additives. In particular, through appropriate choice and / or concentration of such additives, the melting point or the melting range may again be adjusted, as well as other properties such as viscosity, polarity, wetting capacity or the like. Thus, in particular at least one salt and / or at least one sugar may be used as an additive. For example, sole-containing watery solutions, that is, salt-water solutions, for example saline solutions, may be used.

Problems solved by technology

Such cooling elements generally have no own active cooling, in particular no power supply.

However, the disadvantage of such cooling elements or cold packs is that such pre-freezing or sub-cooling to a temperature below the target temperature of the goods to be cooled usually causes temperatures well below phase transition between the solid state of matter and the liquid state of matter of the coolant.

For many types of goods to be cooled, for example in the food industry and / or pharmacy, such sub-cooling of the goods to be cooled involves partly irreversible damage.

When used in households or for food, freezer burn or other damage may occur.

In the field of pharmacy or biology, sensitive samples and drugs may become completely useless by sub-cooling.

Certainly, such “passive” insulation concepts reduce the described problem of initial sub-cooling of the goods to be cooled since the additional layer acts as a “buffer” to build up a temperature gradient between the cooling element and the goods to be cooled, but in such systems, significantly more costly and expensive work steps involving additional handling steps are required since both additional materials (for example an internal box or intermediate layers) and additional operations are required when packing the merchandise.

A further disadvantage of purely passive buffer insulations is that the total service life of the cooling elements is comparatively low.

However, the disadvantages of such structure are comparable with the above-described disadvantages of JP 101 11 057.

Again, a complex structure with additional handling steps is necessary.

Furthermore, the total cooling duration is again limited through the pre-heated intermediate element.

However, also the solution described in WO 00 / 12409 is comparably complex.

Moreover, the internal layer, which again resembles a “pre-heated” layer, limits the entire useful life of the cooling element.

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