The invention relates to a refrigerated display case, an air curtain discharge grille and a method of modifying a refrigerated display case.

The display of chilled or frozen items is commonplace in many retail environments, most notably in supermarkets. Such items are often displayed in refrigerated display cases having hinged or sliding doors, or having an open front. Refrigerated display cases utilise an air curtain which is cooled to below ambient temperature and propelled downward, across the front of the display case (either over the open front or behind the refrigerator doors).

The energy consumed by such refrigerated display cases presents a significant contribution to the overall energy consumption of the supermarket. It is therefore desirable to improve the efficiency of refrigerated display cases.

It has previously been proposed to provide an open refrigerated display case in which each shelf of a display area is provided with a flow control device which stabilises flow in the air curtain. Such a flow control device is disclosed in GB2527628B.

The invention seeks to provide improvements which facilitate the use of flow control devices.

According to an aspect of the disclosure there is provided a refrigerated display case comprising: a refrigerated display area; an air outlet and an air inlet opening into the display area and spaced from one another; a duct fluidically coupling the air inlet to the air outlet, the duct being configured to direct airflow out of the air outlet across the display area and toward the air inlet to form an air curtain across the front of the display area; a flow control device extending transversely across the display area and located at least partially within the air curtain; and a discharge grille located at the air outlet, the discharge grille comprising a cellular structure which defines a plurality of passageways each having an inlet opening and an outlet opening, wherein the inlet openings and the outlet openings of the passageways are aligned and define an inlet plane and an outlet plane; wherein the passageways are arranged such that their longitudinal axes form an oblique angle with the inlet and outlet planes. The cellular structure may be a honeycomb structure.

The flow control device may comprise a stabilising beam which extends transversely across the display area.

The refrigerated display area may comprise a shelf, and the flow control device may be associated with the shelf such that the stabilising beam is arranged outwardly of the shelf in the refrigerated display area to thereby form an inner slot between the shelf and the stabilising beam.

The display area may comprise a plurality of shelves, each shelf being provided with an associated flow control device. The stabilising beam may be an inner stabilising beam and the flow control device may further comprise a second outer stabilising beam arranged outwardly from the inner stabilising beam to thereby form an outer slot between the inner and outer stabilising beams. The refrigerated display case may be an open refrigerated display case (i.e. with no doors).

According to another aspect of the disclosure there is provided an air curtain discharge grille for a refrigerated display case, the discharge grille comprising: a cellular structure which defines a plurality of passageways each having an inlet opening and an outlet opening, wherein the inlet openings and the outlet openings of the passageways are aligned and define an inlet plane and an outlet plane; wherein the passageways are arranged such that their longitudinal axes form an oblique angle with the inlet and outlet planes.

According to another aspect of the disclosure there is provided a method of modifying a refrigerated display case comprising: removing from an air outlet of the refrigerated display case an existing discharge grille which comprises a plurality of passageways which have their longitudinal axes oriented at a first angle; and fitting a replacement discharge grille which comprises a plurality of passageways which have their longitudinal axes oriented at a second angle which is different to the first angle so as to change the path of an air curtain of the refrigerated display case.

The replacement discharge grille may comprise: a cellular structure which defines the plurality of passageways, the passageways each having an inlet opening and an outlet opening, wherein the inlet openings and the outlet openings of the passageways are aligned and define an inlet plane and an outlet plane; wherein the passageways are arranged such that their longitudinal axes form an oblique angle with the inlet and outlet planes.

The method may further comprise installing a flow control device which extends transversely across a display area of the refrigerated display case and located at least partially within the air curtain.

The flow control device may comprise a stabilising beam which extends transversely across the display area.

The replacement discharge grille may cause the path of the air curtain to move so that the stabilising beam is positioned closer to the peak velocity of the air curtain.

The stabilising beam may be an inner stabilising beam and the flow control device further comprises a second outer stabilising beam arranged outwardly from the inner stabilising beam to thereby form an outer slot between the inner and outer stabilising beams.

The disclosure extends to air curtain discharge grilles, refrigerated display cases and methods having any combination of the features described herein, except such combinations as are mutually exclusive.

For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:-

Figure 1 is a side cross-sectional view of an open refrigerated display case (ORDC) comprising a flow control device;

Figure 2 is a perspective view of the flow control device; Figure 3 is a side view of the flow control device of Figure 2;

Figure 4 is a side view showing the flow control device attached to a shelf;

Figure 5 is a plan view of an upper panel of the ORDC;

Figure 6 is a contour and velocity vector plot showing the velocity profile of an air curtain formed by an ORDC;

Figure 7 is a side cross-sectional view through an air curtain discharge grille according to an embodiment of the invention;

Figure 8 is a side cross-sectional view illustrating a method of forming the air curtain discharge grille of Figure 7;

Figure 9 is a contour and velocity vector plot showing the velocity profile of an air curtain formed with the air curtain discharge grille of Figure 7; and Figure 10 is a flowchart of a method of modifying an ORDC.

Figure 1 shows an ORDC 2. The ORDC 2 comprises a cabinet portion formed by a lower wall 4, a back wall 6, an upper wall 8, and left and right side walls (not shown). A lower panel 10, a back panel 12 and an upper panel 14 are disposed within the cabinet portion.

The lower, back and upper panels 10, 12, 14 form a display area 15 which is provided with a plurality of shelves 17 (four are shown) on which items may be displayed. The shelves 17 are affixed to the back panel 12. As shown, the lower, back and upper panels 10, 12, 14 are spaced from the respective lower, back and upper walls 4, 6, 8 to form a duct 16. An intake grille 18 is provided at the lower panel 10 to form an inlet to the duct 16. Similarly, a discharge grille 20 is provided at the upper panel 14 to form an outlet from the duct 16. The intake grille 18 and the discharge grille 20 are thus fluidically coupled to one another by the duct 16. The intake grille 18 and the discharge grille 20 are spaced from the back panel 12 toward the front of the cabinet portion and ahead of the shelves 17. A fan 22 and a heat exchanger 24 are located within the duct 16 adjacent to the intake grille 18 and thus are disposed between the lower wall 4 and the lower panel 10. The fan 22 draws air into the duct 16 via the intake grille 18 which then passes through the heat exchanger 24 where it is cooled to well below the ambient temperature.

After passing through the heat exchanger 24, the air continues through the duct 16 between the back wall 6 and the back panel 12. The back panel 12 is perforated allowing air to pass from the duct 16 into the display area 15 where it cools items located on the shelves 17 and on the lower panel 10.

The remaining air flows through the duct 16 to the discharge grille 20. The air is ejected from the discharge grille 20 and descends over the open front of the display area 15 to form an air curtain 26. The air curtain 26 passes from the discharge grille 20 to the intake grille 18, where it is drawn in by the fan 22 and re-circulated through the duct 16. The air curtain 26 thus forms a non-physical barrier which separates the display area 15 from the ambient air surrounding the ORDC 2.

As shown, a flow control device 102 is attached to each of the shelves (although, in other arrangements, only some of the shelves may be provided with flow control devices 102).

As shown in Figures 2 and 3, the flow control device 102 comprises a pair of brackets 106a, 106b and a pair of elongate elements in the form of stabilising beams 108a, 108b. The brackets 106a, 160b are used to attach the device 102 to a shelf. The beams 108a, 108b are connected by a pair of spacers 1 10a, 1 10b. The spacers 1 10a, 1 10b are provided towards the lateral ends of the beams 108a, 108b. A central spacer 1 12 may also be provided at the centre of the beams 108a, 108b, midway along their lengths.

The beams 108a, 108b are spaced apart from one another by the spacers 1 10a, 110b such that upper edges and lower edges of the beams 108a, 108b run parallel to one another. The beams 108a, 108b are, however, angled relative to one another so that a gap between the beams 108a, 108b tapers, with the upper edges of the beams 108a, 108b being further apart than the lower edges. As shown in Figure 3, the outer beam 108a may be arranged substantially vertically (i.e. with its upper and lower edges aligned in a vertical plane) and the inner beam 108b may be angled so as to form a tapering gap between the beams 108a, 108b.

The device 102 may further comprise a product information strip 1 14. As shown in Figure 3, the product information strip 1 14 clips over the upper and lower edges of the outer beam 108a. The product information strip 1 14 has a channel for receiving tickets which display information regarding products, such as the product’s price.

As shown in Figures 1 and 4, in use, the beams 108a, 106b define a first slot 160 between the outer and inner beams 108a, 108b and a second slot 162 between the inner beam 108b and the outer surface of the shelf.

The first slot 160 tapers from an inlet at an upper end to an outlet at a lower end. The inlet has a greater width than the outlet and a convergent throat is disposed between the inlet and the outlet.

The beams 108a, 108b are positioned such that the air curtain 26 passes through the first and second slots 160, 162. The beams 108a, 108b act to control and stabilise the air curtain so as to maximise the air which is returned to the intake grille 18 and prevent warmer ambient air from mixing with the cold air within the air curtain.

As shown in Figure 5, the discharge grille 20 is formed by a honeycomb panel 146. The honeycomb panel 146 comprises a cellular array or matrix (i.e. comprising a plurality of rows and a plurality of columns of cells) which defines passageways through which air can exit the duct 16 and form the air curtain. The honeycomb panel 146 thus rectifies the air flow as it exits the discharge grille 20 to provide laminar flow, as shown in Figure 6.

Figure 6 does not include any flow control devices 102 (and also does not show the honeycomb panel 146 for clarity) and thus represents the airflow prior to fitting the flow control devices 102. Each of the flow control devices 102 should be positioned in a horizontal direction (i.e. a fore and aft position) such that they lie within the air curtain at its respective vertical position. The position of the beams 108a, 108b within the air curtain influences the efficacy of the flow control device 102 and so should be carefully considered. In particular, it has been found that it is desirable for the inner beam 108b to be positioned in the air curtain such that its leading edge is substantially coincident with the region in which the peak flow velocity occurs.

In some ORDC designs, it is difficult to achieve the required positioning of the flow control devices 102. For example, where the shelves used in the ORDC are relatively short (or the display area is relatively deep), the inner beam 108b must be spaced from the front of the shelf by a significant distance. This can mean that the flow control devices 102 become more prominent to customers, potentially restricting access to and visibility of stock on the shelves, and may be more easily knocked and damaged (e.g. as a result of the longer cantilevered arms or because they project out of the ORDC).

Figure 7 shows a discharge grille 220 which may be used to replace the discharge grille 20 described previously.

As shown, the discharge grille 220 is formed by a honeycomb panel which forms a cellular array (i.e. comprising a plurality of rows and a plurality of columns of cells). The cells of the discharge grille 220 define a plurality of passageways 248 which extend through the thickness of the discharge grille 220. The passageways 248 define an inlet opening 250 at an upper end and an outlet opening 252 at a lower end. The inlet openings 250 all lie in a common inlet plane and the outlet openings 252 all lie in a common outlet plane. The longitudinal axes (extending from the inlet opening 250 to the outlet opening 252) of the passageways 248 are all parallel to one another; however, as shown, the passageways 248 form an oblique angle Q (i.e. not 90 degrees) with respect to the inlet and outlet planes (i.e. the upper and lower surfaces of the honeycomb panel). In this example, the angle Q is 80 degrees such that the passageways 248 are offset by 10 degrees from perpendicular (as in a conventional honeycomb panel).

In some examples, the discharge grille 220 may comprise wedge portions 254 (which may be integrally formed with the honeycomb panel or separate components) at the front and rear edges so that the parallelogram cross-section defined by the angled passageways 248 becomes a rectangle. The discharge grille 220 therefore occupies the same space envelope as the standard discharge grille 20 and so can be interchanged easily.

Figure 8 demonstrates how the discharge grille 220 can be formed by cutting a section from a conventional honeycomb panel. As shown, the honeycomb panel is cut along an upper cut line 256a and a lower cut line 256b at the desired offset angle a. In other examples, the discharge grille 220 can be manufactured to have angled passageways.

The angled passageways 248 cause the air curtain to deviate from its original, intended route, as seen when using a conventional honeycomb discharge grille.

In the example shown in Figure 7, the passageways 248 of the discharge grille 220 are offset by 10 degrees from perpendicular, as described above. The discharge grille 220 is oriented such that passageways are angled into the display area 15, with the outlet openings 252 of each passageway 248 located closer to the adjacent shelf and back panel 12 than the inlet openings 250.

Accordingly, as seen in Figure 9 (when compared with Figure 6), with the discharge grille 220 in place, the air curtain is moved inwards so that it is positioned closer to the end of the shelves, particularly the uppermost shelf.

The offset angle of the discharge grille 220 can be selected to provide the required deviation of the air curtain. For example, the offset angle may be selected so that the inner stabilising beam 108b of the flow control device 102 on the uppermost shelf has its leading edge substantially coincident with the region in which the peak flow velocity of the air curtain occurs. The discharge grille 220 and offset angle thus provide a simple means for adjusting the position of the stabilising beams 108a, 108b relative to the air curtain without needing to modify the flow control device 102 itself.

There may also be other situations where it is desirable to move the air curtain away from the shelves. For example, if the peak flow velocity is located too close to the shelves to allow the stabilising beams 108a, 108b to be positioned appropriately. The discharge grille 220 can therefore be reversed so that the passageways 248 are angled away from the display area 15, with the outlet openings 252 of each passageway 248 located farther from the adjacent shelf and back panel 12 than the inlet openings 250.

Figure 10 shows a flowchart describing a method of modifying an ORDC. At step S1 , the existing discharge grille of the ORDC is removed. The required offset angle is determined at S2 and the new discharge grille having the required offset angle is then fitted to the ORDC. The air curtain is therefore made to deviate away from its original, intended path. At step S4, flow control devices are affixed to the shelves of the ORDC in optimised positions for the modified air curtain path. The offset angle may be determined using computational fluid dynamics or empirically. It will be appreciated that, although step S1 clearly must precede step S3, the steps may be reordered. It will be appreciated that the flow control device may differ from that described above. For example, the flow control device may have only a single beam or may itself be formed by a honeycomb panel. Further, although the invention has been described with reference to an open refrigerated display case, it may also be utilised on closed refrigerated display cases with doors.

Although the discharge grille has been described as being formed by a honeycomb panel which may generally be considered as having hexagonal cells, it will be appreciated that other cellular structures may be used which form a matrix of passageways. The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention.