The invention relates to improvements in shelfs for refrigerators, and refrigerators comprising such a shelf.

Open display refrigerators are commonly used in retail environments, such as supermarkets and grocery stores. An open display refrigerator allows customers to view and readily access chilled goods that are stored within the refrigerator.

This type of refrigerator typically has a perforated wall adjacent the interior of the refrigerator, wherein the perforations (or holes) in the perforated wall allow cooled air to pass from a duct or cavity that is typically located behind the perforated wall into the interior of the refrigerator, thereby cooling the interior of the refrigerator and any items stored in the interior of the refrigerator. The perforated wall is usually the rear wall of the refrigerator, but can be any wall (or multiple walls) adjacent the interior of the refrigerator. The air may be cooled by a heat exchanger integral to the refrigerator or, alternatively, cooled air may be delivered to the refrigerator. Usually, at least some of this air will be recovered from the interior of the refrigerator by an air inlet near the base of the refrigerator. This recovered air will then usually be re-circulated by a fan through a heat exchanger, into the duct or cavity and out into the interior of the refrigerator.

It is known to retrofit one or more "ducted shelves" to a conventional refrigerator. Typically, these ducted shelves have an air inlet in the rear of the shelf and a duct formed between first and second surfaces of the shelf, wherein the first surface corresponds to the upper surface of the shelf in use and the second surface corresponds to the lower surface of the shelf in use. The air inlet is of the same height as the shelf and covers one or more perforations in the rear wall. This means that when the ducted shelves are fitted to a perforated wall of a refrigerator, in use cooled air passes through the perforations in the wall and into the interior of the ducted shelf. The cooled air then circulates in the interior of the ducted shelf, cooling the surface of the shelf that receives items to be refrigerated, with the cooled surface providing enhanced cooling of the items. However, as the air inlet in the rear of the ducted shelf is relatively narrow, only having the same height as the shelf itself, the air inlet does not cover many perforations and as a consequence little air passes through the perforations and into the interior of the ducted shelf.

A solution to this problem is taught in GB 2540021, which discloses a refrigerator with at least one ducted shelf, but with the addition of a deflector that extends though the rear wall of the refrigerator and into a cavity behind the wall of the refrigerator, thereby partially blocking the cavity. As described above, the cavity carries cooled air from a heat exchanger to other parts of the refrigerator. Cooled air is deflected by the deflector and passes from the cavity and through the rear wall of the refrigerator, through the interior of the shelf and optionally out of an air outlet located near the front of the shelf onto items located below the shelf. An advantage of such a shelf is that it provides enhanced cooling for items placed on the shelf, when compared to a standard ducted shelf, due to deflector deflecting more cooled air from the cavity and into the interior of the shelf. However, as the shelf of GB 2540021 comprises a deflector that passes through the rear wall of the refrigerator and into the cavity, it is not possible to retrofit such a shelf to an existing refrigerator wherein the rear wall comprises a plurality of relatively small perforations. Such a solution requires a custom rear wall for receiving the shelves and the deflector, which makes it impractical or expensive to retrofit to existing refrigerators with perforated rear walls.

It would therefore be desirable to provide a more effective cooling shelf for a refrigerator, which is able to be retrofitted to existing refrigerators.

In accordance with a first aspect of the invention, there is provided a shelf for a refrigerator, the shelf comprising: a first surface for receiving items when the shelf is in use; the first surface being spaced apart from a second surface to form a duct between the first and second surfaces; wherein the duct allows fluid communication between an air inlet and an air outlet, the duct being flared to form the air inlet such that the cross sectional area of the air inlet is larger than that of the duct.

A technical advantage of the shelf is that, in use, the air that circulates through the shelf cools items located on the first surface of the shelf and the air outlet can be used to direct cooled air onto additional items located below the shelf. The flared air inlet covers more perforations than a shelf with an air inlet that is the same height as the shelf, thereby collecting more cooled air than would normally pass through the perforations and into the interior of a standard cooling shelf. Due to the flare and the relatively large cross section of the air inlet, a diverter does not need to be used to collect air from a cavity behind the perforated wall.

Typically the shelf will be made of metal, but the shelf could be made of any material that allows a duct to be formed between first and second surfaces, such as plastic.

The cross sectional area of the air inlet may be 1.5 times, 2 times, 3 times or any other multiple of the cross sectional area of the duct.

Usually, in use, the shelf will be retrofitted to a refrigerator with a perforated wall adjacent the interior of the refrigerator, wherein the perforations (or holes) allow cooled air to pass from a duct or cavity into the interior of the refrigerator, thereby cooling the interior of the refrigerator. The shelf can be retrofitted to existing refrigerators with a perforated wall, as there is no need to insert a deflector into the duct or cavity behind the perforated rear wall. The shelf can be attached to a perforated wall of a refrigerator such that the flared duct covers one or more perforations, thereby collecting cooled air into the interior of the shelf that would normally pass immediately out of the perforations and into the interior of the refrigerator.

Throughout the specification, "perforation" or "perforations" covers any sized hole or holes through which air can pass. This may include a large number of relatively small perforations and/or may include a smaller number of large perforations. Additionally the air inlet and/or (as discussed below) a blanking plate may cover a perforation that is substantially the width of the rear wall and/or the height of the air inlet and/or blanking plate of the shelf. The air inlet and/or blanking plate of the shelf may only partially cover a perforation or may completely cover a perforation.

In some embodiments, at least a part of the air outlet is formed in the second surface of the shelf. A technical advantage of having at least a part of the air outlet formed in the second surface (which, in use, is the lower surface) of the shelf is that, in use, cooled air can be directed onto items on the shelf below, thereby providing additional cooling to those items. As such, in use, items can be cooled from below by the air passing through the shelf and from above by air passing out of the air outlet of a shelf above.

In some embodiments, at least a part of the air outlet is formed in an edge of the shelf that is opposite the air inlet (i.e. the front edge of the shelf, which faces users of the refrigerator in use).

In some embodiments, the shelf further comprises a diverter that is positioned at and extends into the air outlet.

A technical advantage of providing a diverter that is positioned at and extends into the air outlet is that air can be more accurately directed than with a simple opening. The diverter can have a smooth surface and/or have a quarter-circle cross section, thereby reducing eddies in the airflow and/or making the airflow more laminar, which improves the accuracy of the airflow.

In some embodiments, the first surface is broadly planar and the second surface is flared to form the air inlet.

A technical advantage of such an arrangement is that when the shelf is installed in a refrigerator, the flare extends in a downwards direction towards the floor (as the first surface corresponds to the upper surface and the second surface corresponds to the lower surface in use). The advantage arises as there is typically a gap between the top of items stored on a first refrigerator shelf and a second shelf above the items. If the second shelf comprises a downwardly extending flare, the flare extends into a space in the interior of the refrigerator that would not typically be used by items on the first shelf. Having a flare that extends in a downwards direction hence reduces the impact on the reduction in loading capacity of a refrigerator that would typically arise when the interior space is reduced. In some embodiments, the first surface is flared to form the air inlet and the second surface is broadly planar.

In some embodiments, the shelf further comprises a blanking plate proximate the first surface, wherein the blanking plate extends in a direction that is away from the second surface.

In some embodiments, the shelf further comprises a blanking plate proximate the second surface, wherein the blanking plate extends in a direction that is away from the first surface.

The blanking plate may be integral to the shelf or alternatively may be separate from the shelf. If the blanking plate is provided separately to the shelf, it is contemplated that a kit comprising the blanking plate and the shelf may be provided. Typically the blanking plate is made of metal, but can be formed of any other suitable material, such as plastic.

A technical advantage of the blanking plate is that, in use, it blocks air from passing through perforations and into the interior of the refrigerator. This increases the air pressure through the shelf, without the need for a special rear wall and hence can be retrofitted to existing refrigerators. An advantage of the increase in pressure is that more cooled air passes through the shelf, thereby increasing the efficiency of the cooling of the items placed on the shelf.

In some embodiments, the blanking plate extends away from the surface (i.e. the first surface or the second surface) in the same plane as the air inlet.

A technical advantage of having a blanking plate that extends away from the first surface or the second surface of the shelf in the same plane as the air inlet is that this causes the blanking plate to be as close as possible to the perforated rear wall of the refrigerator when the shelf is in use. The closer the blanking plate is to the rear wall of the refrigerator in use, the more effective it is at blocking the perforations in the rear wall and preventing cooled air from coming out of the perforations. Ideally, the blanking plate will be flush with the perforated rear wall in use; however, it is recognised that there may be a relatively small gap between the blanking plate and the rear wall in use.

In accordance with a second aspect of the invention, there is provided a refrigerator comprising: a refrigerated interior space; a wall adjacent to the interior space, wherein the wall comprises one or more perforations and, in use, cooled air passes through the one or more perforations in the wall and into the refrigerated interior space; and the shelf of any previous claim, wherein the shelf is attached to the perforated wall such that, in use, cooled air passes through at least one of the perforations in the wall and into the air inlet of the shelf.

In use, air passes out of the one or more perforations and into the air inlet of the shelf. The cooled air may then continue to pass through the interior of the shelf and out of an air outlet at the opposite end of the shelf to the air inlet. In some alternatives, the air outlet may be co-located with the air inlet, such that air passes back through one or more, different perforations in the rear wall. In such an alternative, the interior of the shelf may be split broadly in two, such that there is an outward path for the air to follow away from the air inlet and a return path for the air to follow back towards the air outlet and for return through at least one perforation in the rear wall (separate to the at least one perforation the air passed through initially) and into the cavity behind the rear wall of the refrigerator.

In some embodiments, the wall comprises at least first and second perforations, and wherein the cooled air passes through at least the first perforation, but not the second perforation, and into the air inlet of the shelf and wherein the blanking plate covers at least the second perforation, but not the first perforation.

In some embodiments, air in the refrigerated interior space is separated from air in a space exterior to the open display refrigerator by an air curtain established by a fan which blows air through an air curtain outlet towards a corresponding air curtain inlet which recovers air from the air curtain for recirculation to the air curtain outlet. An embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 shows an open display refrigerator with conventional shelves.

Figure 2 shows the airflow through an open display refrigerator with conventional shelves.

Figure 3 shows an open display refrigerator fitted with shelves in accordance with an embodiment of the invention.

Figure 4 shows the airflow through a shelf in accordance with an embodiment of the invention.

Figure 5 shows a known, prior art, ducted shelf.

Figure 6 shows how the air inlet of a shelf in accordance with an embodiment of the invention covers an enhanced number of perforations.

Figure 7 shows the enhanced cooling of items stored in a refrigerator that uses a shelf in accordance with an embodiment of the invention.

Figure 8 shows the enhanced cooling of items stored in an open display refrigerator that uses a shelf in accordance with an embodiment of the invention as well as airflow through the open display refrigerator.

Figure 1 shows a cross-section through a conventional open display refrigerator 1. The refrigerator has an interior space which is maintained at a lower than ambient temperature. Within the interior space, there are five shelves 3 and a base. In use, the refrigerator 1 establishes an air curtain (as shown in Figure 2) by blowing cold air from an air outlet 2 towards an air inlet 4. In use, air inlet 4 recovers air from the air curtain and at least one fan

5 within the refrigerator 1 recirculates the air to the air outlet 2 via a cooling heat exchanger

6 and a duct 8. The cooling heat exchanger 6 is typically placed within the refrigerator 1 and maintains the recirculated air (and hence the air blown through the air outlet 2 to form the air curtain) at a desired temperature below ambient temperature. In use, cooled air from the duct 8 also passes through the perforations in the perforated rear wall 7 of the refrigerator to help cool items stored in the refrigerator 1.

Figure 2 shows the flow of air through the conventional open display refrigerator 1 of Figure 1. In particular, the arrows in Figure 2 shows how an air curtain 9 is established between the air outlet 2 and the air inlet 4 and how the at least one fan 5 within the refrigerator 1 recirculates the air to the air outlet 2 via a cooling heat exchanger 6 and a duct 8. Further, figure 2 shows how cooled air in the duct 8 (arrow 10) passes from the duct 8 and through perforations in the rear wall of the refrigerator (arrow 11). The air then passes over the shelves 3 of the refrigerator 1 (arrow 12) and finally, this air hen passes over the edge of the shelf 3 (arrow 13) and then down towards the air inlet 4. Air from the air curtain 9 prevents at least some of the air from exiting the refrigerator 1 via the open front of the refrigerator.

Figure 3 shows an open display refrigerator 1 fitted with five shelves 14 in accordance with the present invention. Although shown attached to an open display refrigerator in this example, the shelves can be fitted to any refrigerator with a perforated wall through which air passes. The shelves 14 comprise an air inlet 15 which, in use, covers one or more perforations in the perforated rear wall 7. Although the figure shows the air inlet covering the height of two perforations, as discussed above, the perforations may be of any size. The shelves also comprise a flared portion 16, such that the air inlet has a larger cross section than the duct formed between a first surface 17 and a second surface 18 of the shelf 14. The flared portion 16 is shown as extending in a downwards direction towards the base of the refrigerator 1. Although not shown, it is contemplated that the flared portion 16 may alternatively extend in an upwards direction towards the top of the refrigerator 1 or there may be two flared portions that extend away from the shelf 14 in opposite directions.

In use, air flows through the perforations, through the air inlet 15, through the duct formed between the first 17 and second 18 surfaces and, optionally, out of an air outlet 19.

Although not shown here, other arrangements are contemplated. If the shelf does not comprise the air outlet 19, air may circulate in the interior of the shelf and also leave through the air inlet 15. The shelf 14 also comprises an optional diverter 20 for directing air out of the air outlet 19. Also shown is an optional blanking plate 21 for covering perforations above the shelf 14. Although not shown, it is contemplated that the blanking plate 21 may extend in a downwards direction towards the base of the refrigerator 1 or the shelf may comprise two blanking plates extending away from the shelf 14 in opposite directions. The blanking plate 21 may be integral to the shelf or, alternatively, the blanking plate and the shelf may be provided separately as part of a kit for retrofitting to existing refrigerators. It is contemplated that shelves made in accordance with the present invention can be retrofitted to existing refrigerators with perforated walls. The shelves may be provided with tabs for slotting into a receiving portion in a refrigerator. The shelves may be provided with appropriate "male" and/or "female" attachment portions that are received by corresponding "female" or "male" attachment portions on the refrigerator wall in use. Alternatively, the shelves may be screwed or riveted onto the rear wall of a refrigerator in use.

Figure 4 shows the airflow through a shelf 14 for a refrigerator in accordance with the present invention. As can be seen, in use, air passes through perforations in the perforated rear wall 7 (arrow 11). In use, the air passes through the duct formed by the first 17 and second 18 surfaces of the shelf 14 (arrow 22) and out of the air outlet 19. In use, the diverter 20 directs the air that passes out of the air outlet 19 in a downwards direction.

Figure 5 shows a known ducted shelf 23 for a refrigerator (as described above). The known ducted shelf 23 differs from the shelf of the present invention in that the air inlet is not flared. Instead, the known ducted shelf 23 makes use of a diverter 24 to help collect air from a duct behind the rear wall 26 of a refrigerator. Air flows through the interior of the shelf (arrow 25) and out of an air outlet. As can be seen, it is difficult to retrofit such a ducted shelf 23 to a refrigerator with a standard perforated rear wall, as typically the perforations will not be large enough to receive the diverter 24. As such, the standard perforated rear wall would need to be replaced.

Figure 6 shows the shelf 14 of figure 4. As indicated by the arrow proximate the air inlet 15, the flared portion 16 ensures that more perforations are covered than if the air inlet was the same height as the shelf, as in figure 5. This increase in covered perforations allows more cooled air to enter the interior of the shelf 14 and negates the need for the diverter shown in Figure 5. As such, the shelf 14 can be retrofitted to existing refrigerators with perforated walls, because the air inlet simply covers the perforations and arrangement to receive a diverter (as with the known shelf shown in figure 5) is not needed.

Figure 7 shows the shelf 14 of figures 4 and 6 in use. As before, in use, cooled air flows from the duct and through perforations in the perforated wall 7 (arrow 11). In use, items 28a on the first surface 17 are cooled by the cooled air that passes through the interior of the shelf 14. In use, items 28b that are located on a shelf below the present shelf 14 are cooled by the cooled air that passes out of the air outlet 19 and directed by the diverter 20. This arrangement is more efficient that simply allowing air to pass through the perforations of the perforated rear wall 7, not least because this arrangement makes use of conduction as well as convection, in that the cold air cools the first surface 17 of the shelf and the cold first surface 17 conducts the heat away from the items 28a. The air outlet 19 and diverter 20 direct air onto items at the front of the shelf, which provides additional cooling which would not be achieved by air passing out of the perforations and over items on the shelf. Typically, items at the front of the shelf would be warmer than items at the rear of the shelf as they are further away from the perforations and hence the cooled air passing out of the perforations. As can be seen, in typical use, the flared portion does not interfere with the way a shelf is loaded as items are typically not loaded right to the rear of a refrigerator. Figure 7 also shows how the blanking plate 21 deflects cooled air back into the duct and prevents it from exiting through perforations above the shelf. In use, this causes more air to exit through shelves that are located above the present shelf.

Figure 8 shows an open display refrigerator fitted with shelves 14 in accordance with the present invention. As can be seen, in use, an air curtain 9 is established between the air outlet 2 and the air inlet 4. In use, cooled air passes from the duct 8 through perforations in the perforated wall 7, through the air inlets 15 of the shelves 14, through the interior of the shelves 14 and out of the air outlets 19 of the shelves 14. As shown in figure 7, in use, the shelves 14 cool items 28a placed on the first surfaces 17 of the shelves 14 by conduction and cool items 28b placed on the shelf below by directing cooled air onto the items 28b. As discussed above, in use, this provides more effective cooling than a conventional open display refrigerator and the shelves 14 are able to be retrofitted to existing refrigerators with perforated walls.