NL2024343B1 - Passive thermally insulated transport container - Google Patents

Abstract

Passive, thermally insulated container with a heat accumulator for transporting products in the container at a temperature above or below ambient temperature. The container has thermally insulated side, top and bottom walls bounding a transport chamber for accommodating products to be transported. Goods carriers in the transport chamber are shaped and dimensioned for leaving passages for circulation of air through the goods carriers and/or between the goods carriers and the vertical walls. One or more vanes is or, respectively, are movably suspended in the transport chamber so as to move in reaction to agitation of the container.

Description

P125319NLO0 TITLE: Passive thermally insulated transport container

FIELD AND BACKGROUND OF THE INVENTION The invention relates to a passive, thermally insulated container for transporting products at a temperature above or below ambient temperature. In this context ‘passive’ is understood as without provisions for supplying energy for causing a heat flow opposite to the heat flow from the environment into the transport chamber as a result from the difference in temperature between the environment of the container and the transport chamber.

Such containers are for instance used in the distribution of food such as bakery product such as pastry and cake, meat and meat products, dairy products and fruits from a production facility or distribution centre to retail outlets and commercial and institutional kitchens, i.e. over relatively short distances to a substantial number of addresses. The containers are mostly for keeping the products cool (e.g. frozen or at or near 4 °C), but in some applications, such as the supply of food to events or the delivery of hot meals, the containers may also be arranged to keep the products warm.

Passive thermally insulated containers are particularly suitable for such applications, because of the simplicity and ruggedness and because it is not necessary to provide energy to the containers.

Such containers usually have thermally insulated side, top and bottom walls bounding a transport chamber for accommodating the products to be transported, goods carriers in the transport chamber shaped and dimensioned for leaving passages for circulation of air through the goods carriers and/or between the goods carriers and the vertical walls and at least one heat accumulator. The goods carriers can for instance be crates, boxes, platforms, gratings or plates, which may optionally be provided with wheels or sliders.

In use, the heat accumulators are cooled to a temperature below the desired temperature in the transport chamber if the products are to be maintained cooler than the ambient temperature or heated to a temperature above the desired temperature in the transport chamber if the products are to be maintained warmer than the ambient temperature. During transport of products to be kept cool, the cooled heat accumulator in the transport chamber absorbs heat from the transport chamber, thereby counteracting heating up of the transport chamber as a result of heat flow from the environment into the transport chamber. Conversely, during transport of products to be kept warm, the cooled heat accumulator in the transport chamber gives off heat to the transport chamber, thereby counteracting cooling of the transport chamber as a result of heat flow from the transport chamber to the environment.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a passive, thermally insulated transport container in which products can be maintained within a desired temperature range longer, without increasing capacity of the heat accumulator or thermal insulation.

According to the invention, this object is achieved by providing a container according to claim 1.

In use, agitation of the container occurs in particular during transport in a vehicle, for instance if a lorry or van transporting the container drives over bumps and undulations of a road surface, accelerates and decelerates. Agitation of the container also occurs for instance if the container is rolled over bumps and undulations of a pavement or floor surface and if the container is lifted and lowered.

Because at least one vane is movably suspended in the transport chamber so as to move in reaction to agitation of the container, agitation to which the container is submitted during transport causes the vane or vanes to move, which in turn causes agitation of the air in the transport chamber adjacent to the vane or vanes. Thus, air in the container is mixed, which counteracts the formation of relatively warm or cold spots in the container where product temperature exceeds the maximum temperature of a desired temperature range or is below the minimum temperature of the desired temperature range. Thus, products in zones of the transport chamber where temperature tends to converge to the ambient temperature earlier than in other zones of transport chamber can be maintained within a desired temperature range for a longer period of time. Accordingly, the products can be transported in the container longer while ensuring that the temperatures of all products in the container are maintained within the desired temperature range. Particular elaborations and embodiments of the invention are set forth in the dependent claims. Further features, effects and details of the invention appear from the detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 11s a side view of an example of a container according to the invention; Fig. 2 is a front view of the container shown in Fig. 1; Fig. 3 is a cross-sectional side view along a plane ITI-III in Fig. 2; Fig. 4 is a cross-sectional front view along a plane IV-IV in Fig. 3; and Fig. 5 1s an enlarged view of detail Vin Fig. 4.

DETAILED DESCRIPTION In the drawings an example of a container 1 according to the invention is shown. The container 1 is a passive, thermally insulated container for transporting products at a temperature below ambient temperature. The container 1 is passive, i.e. it is not provided with any equipment for driving a heat flow opposite to the heat flow through the thermal insulation. Accordingly, the container 1 is of a relatively low cost design and can be used without provisions for supplying energy during transport or recharging batteries or the like between transports.

The container 1 has thermally insulated vertical, top and bottom walls 2-7 bounding a transport chamber 8 for accommodating products to be transported. The wall 2 1s a top wall and the wall 7 1s a bottom wall, which 1s mounted on a cart 10 equipped with caster wheels 11 and wheels 12 with rotation axes in fixed orientations relative to a platform 13 of the cart 10. The cart is not shown in Figs. 3 and 4. The vertical walls 3-6 form a front door 3, side walls 4, 5 and a rear wall 6. The front door 3 is pivotable between an open position (not shown) and a closed position about hinges 22, 23. The door 3 can be locked in the closed position by means of bolts 24, 25 hooking behind bolt catchers 26, 27. The bolts 24, 25 are coupled to a handle 28 for simultaneous operation of the bolts 24, 25.

Goods carriers, in this example in the form of crates 9, are arranged in the transport chamber 8. Instead of crates, the goods carriers may also be provided in other forms, for instance in the form of boxes, platforms, gratings or plates, which may optionally be provided with wheels or sliders. The crates 9 are shaped and dimensioned for leaving passages for circulation of air through the crates 9 and between the crates 9 and the vertical walls 3-6 bounding the transport chamber 8. For allowing circulation of air through the crates 9, the crates 9 are provided with openings 14-18 in vertical walls 19, 20 and bottom wall 21 of the crates 9 as is shown for the topmost one of the crates 9m figs. 3 and 4. For allowing air circulation between the crates 9 and the vertical walls 3-6 bounding the transport chamber 8, the vertical walls 19 are located spaced (preferably at least 0.5 cm) from the vertical walls 3-6 bounding the transport chamber 8. Flanges projecting from the vertical walls of the crates 9 to the vertical walls 19, 20 can maintain this spacing. The flanges can be provided with openings or recesses for allowing air to pass through, in particular through the flanges that are oriented horizontally or with a substantial horizontal directional component (e.g. at angles of 30° or more to the vertical direction). Other solutions for keeping the crates or other goods carriers spaced from the vertical walls bounding the transport chamber, such 5 as projections from the vertical walls bounding the transport chamber, are also conceivable.

Thermal insulation is achieved by counteracting heat flows in the form of conduction, convection and radiation. This is achieved by providing the walls 2-7 with insulating material of sufficient thickness (conduction) and sufficient sealing of the transport chamber 8 from the environment (convection). The walls 2-7 may also be provided with reflective surfaces such as aluminium foil (radiation). The insulating material may for instance be plastic foam, which consists of small spaces surrounded by solid walls, fibrous material, or loose-fills (e.g. a mass of unstructured fibres composed of rock slag, glass or alumina-silica or powders, such as perlite, silica aerogel or adiatomaceous earth). The thermal insulation is preferably sufficient to achieve a U value of less than 0.8 W/m2.K or, with increasing preference, less than 0.65 W/m2.K or 0.5 W/m2.K.

Heat accumulators 29, 30 are supported in the transport chamber 8 by support members 31, 32 and rest on flanges 33, 34 of the support members 31,

32. In Fig. 3, the container 1 is shown without the heat accumulators 29, 30, which are removable for re-cooling in a freezer. The heat accumulators 29, 30 are preferably plastic containers filled with a gel on water basis, so that the water can be frozen to ice, thereby accumulating a large amount of energy at the transition from water to ice. The containers may also include additives such as salt or alcohol, to lower the temperature of the water/ice transition, for increasing the cooling effect of frozen heat accumulators 29, 30. Instead of inside the transport chamber 8, the heat accumulators may also be provided elsewhere in the container, for instance in a separate compartment in the container in convective heat exchange communication with the transport chamber. Also, as an alternative, a single heat accumulator or a larger number of heat accumulators may be provided.

Vanes 35, 36 are movably suspended in the transport chamber 8 so as to move in reaction to agitation of the container 1, such as agitation to which the container 1 1s submitted during transport.

Agitation to which the container 1 is submitted during transport causes the vanes 35, 36 to move, which in turn causes agitation of the air in the transport chamber 8 adjacent to the vanes 35, 36. Thus, air in the transport chamber 8 in the container 1 is mixed, which counteracts the formation of relatively warm or cold spots in the container 1 where product temperature exceeds the maximum temperature of a desired temperature range. Thus, products in zones of the transport chamber 8 where temperature tends to rise fastest can be maintained within a desired temperature range for a longer period of time. Accordingly, products can be transported in the container 1 longer while ensuring that the temperatures of all products in the container 1 are maintained within the desired temperature range.

The vanes 35, 36 are suspended for oscillating movement in reaction to the agitation of the container 1, so that agitation is converted into movement of the vanes 35, 36, and thereby movement of air in the transport chamber 8, particularly effectively. As an alternative, it would for instance be possible to cause the vanes to rotate in one sense of rotation only, e.g. using a one way clutch, in response to agitation of the container.

In the present example, agitation of the container 1 as occurring during transport is converted particularly efficiently into movement of the vanes 35, 36, because the vanes 35, 36 are parts of swings 37, 38. Suspended as part of the swings 37, 38, the vanes 35, 36 move out of positions of equilibrium particularly easily, and keep swinging after an impulse for a relatively long time. However, other suspensions of the vanes allowing oscillating movement are also conceivable, such as suspension by one or more springs.

For obtaining a compact construction that effectively induces heat distribution, the vanes 35, 36 are arranged below the heat accumulators 29,

30. Furthermore, suspension arms 39, 40 of the swings extend vertically along portions of the heat accumulators 29, 30 and are suspended so as to be pivotable about pivot axes above a lowermost end of the heat accumulators 29,

30. Thus, oscillation of the swings 37, 38 causes the vanes 35, 36 to move mainly horizontally along paths closely below the heat accumulators 29, 30, so that air cooled by the heat accumulators 35, 36 is effectively urged away from the heat accumulators towards the vertical walls 3-6 of the transport chamber 8, where the relatively cooled air can sink between the products in the crates 9 and the vertical walls 3-6 of the transport chamber 8.

Heat distribution is enhanced particularly effectively, because all the crates 9 are arranged below the heat accumulators 29, 30 and the vanes 35, 60 are arranged between, on one side, the heat accumulators 29, 30 and, on an opposite side, all the crates 9. Thus, cooled air urged away from the heat accumulators 29, 30 tends to sink along all the crates 9.

If the container is to be used for transporting heated products that are to be kept at a temperature well over the ambient temperature, for the same reasons as discussed above, the vertical configuration of vanes, crates and heat accumulators is preferably inverted, i.e. the heat accumulators are then preferably arranged at a bottom end of the container, the vanes are then preferably arranged above the heat accumulators and the crates are then preferably all arranged above the vanes.

For avoiding damage to the vanes 35, 36 when the container 1 is loaded, unloaded or cleaned and for a particularly even temperature distribution, a shield 41 1s provided between, on one side, the vanes 35, 36 and, on an opposite side, the crates 9. The shield 41 is shaped and dimensioned for leaving passages 42-46 for circulation of air between the shield 41 and the vertical walls 3-6. The passages 42 form openings in flanges 47 of the shield 41, which allow cool air to move off the shield 41 towards the side walls 4, 5.

Furthermore, the shield 41 is dimensioned so as to leave a gap 43 between the shield 41 and the door 3, a gap 44 between the shield 41 and the rear wall 45 and gaps 45, 46 between the shield 41 and the side walls 4, 5. The shield 41 also shields products in upper crates 9 from excessive cooling by the heat accumulators 29, 30, while urging air to the gaps 43-46 along the vertical walls 3-6 promotes the descent of cool air towards the lower crates that are more remote from the heat accumulators 29, 30. As is best seen in Fig. 3, the vanes 35, 36 are arranged generally parallel to each other in a row in a horizontal direction transverse to main axes of extension of the vanes 35, 36. Thus, the vanes 35, 36 occupy a relatively flat horizontal layer in the transport chamber 8 between the crates 9 and the heat accumulators 29, 30 and nevertheless are capable of effectively displacing air from near the heat accumulators 29, 30. For a compact construction occupying little space in the transport chamber 8, it 1s also advantageous that the vanes 35, 36 are elongated in a horizontal direction.

Furthermore, the vanes have heights varying along the length of the vanes 35, 36. This further enhances displacement of air in the directions of the main axes of extension of the vanes 35, 36. Some of the vanes 35, 36 have a smallest height in a central portion of the vane 35 and wherein some of the vanes 36 have a smallest height in at least two sections in longitudinal direction of that vane, spaced from a centre of that vane 36. The two types of vanes 35, 36 are arranged in an alternating fashion.

If the vanes 35, 36 are not moving in a synchronized fashion, air displaced by a high portion of one vane 35 or 36 can pass relatively easily along an adjacent low portion of a neighbouring vane 36, 35. Thus, air is to a lesser extent trapped between vanes 35, 36 and a larger volume of air displaced by one vane 35, 36 is picked up by the neighbouring vane 36, 35 upon the next movement of the neighbouring vane 36, 35.

Claims (10)

Conclusions A passive, thermally insulated container for transporting products at a temperature above or below ambient temperature, the container comprising: thermally insulated side, top and bottom walls defining a transport chamber for storing products to be transported; goods carriers in the transport chamber which are shaped and dimensioned to leave passages for circulation of air through the goods carriers and/or between the goods carriers and the vertical walls; and at least one heat accumulator; wherein at least one vane is movably suspended in said transport chamber so as to move in response to shaking of the container. A container according to claim 1, wherein the paddle is suspended for oscillating movement in response to shaking of the container. A container according to claim 2, wherein the paddle forms part of a swing. A container according to claim 3, wherein the vanes are disposed below the at least one heat accumulator, swing suspension arms extend vertically along at least a portion of the at least one heat accumulator and the suspension arms are suspended so as to be pivotable about a pivot axis above. a lower end of the at least one heat accumulator. A container according to any one of the preceding claims, wherein all the crates are arranged below the at least one heat accumulator or all the crates are arranged above the at least one heat accumulator and wherein the blades are arranged between, on one side, the at least one heat accumulator and, on a opposite side, all goods carriers. A container according to any preceding claim, further comprising a screen between, on one side, the at least one vane and, on an opposite side, the goods carriers, the screen being shaped and sized to leave passageways for circulation of air through the screen and/or between the screen and the vertical walls. A contamer according to any one of the preceding claims, comprising a plurality of the blades arranged generally parallel to each other in a row in a horizontal direction transverse to major axes along which the blades extend. A container according to any preceding claim, wherein the blades are elongated in a horizontal direction and wherein at least one of the blades has heights varying along the length of said at least one blade. A container according to any preceding claim, wherein at least a plurality of the blades have heights varying along the length of said at least one blade, some of the blades having a smallest height in a central portion of the blade and some of the blades the blades have a minimum height in at least two sections longitudinally of that blade, spaced from a center of that blade. A container according to any one of the preceding claims, wherein the walls have a thermal conductivity of less than 0.8 W/m 2 .K.