Cooling cabinet

Abstract

 A cooling cabinet (1) has two cooling air streams (22,23) projected over a display surface (6). An outer (22) of the stream is projected at a lower angle to the vertical than an inner (23) and is coherent (jet-like) whereas the inner is turbulent.
The cool air of the inner stream falls vertically onto the display surface (6) with minimal lateral velocity. The cool air of the outer stream just reaches a shelf (10), with enough velocity to just spill off a rear edge (26) thereof.

Description

[0001] This invention relates to cooling cabinets, and in particular to a type of such cabinet called a delicatessen cabinet, where consumables are laid out for display to the public on a low-level tray or base; they may be accessible only from the back of the cabinet. Temperatures of the goods are typically in the range -2 to +2°C.

[0002] One such cabinet is seen in GB-A-2251928 which is very typical of the prior art in that the cooled air is projected forcibly in a protective curtain over the top of the goods in the cabinet; in this case the display cabinet is not protected from access by the general public.

[0003] There are problems with prior art delicatessen cabinets. One such problem is the drying of e.g. meats through "velocity burn", because by transporting the cold air over the product a process of dehumidification occurs and unwrapped meats tend to discolour and curl at the corners with the consequential loss of product weight due to evaporation.

[0004] Numerous methods have been tried to overcome problems caused by "velocity burn" by installing additional devices such as humidifiers to artificially increase the amount of moisture present within the cabinet and hence reduce the effects of high air velocities over the goods. Devices such as these add cost to the cabinet and require costly time-consuming maintenance, and if constant humidity is not maintained often result in slime occurring on unwrapped products.

[0005] The solution to this problem adopted according to the invention is to do two things. Firstly to reverse the direction of flow of the cooled air so that it issues from the front of the cabinet.

[0006] Secondly and critically, however, to split the cooled air flow issuing at the front of the cabinet into two portions, the outer (forward) of which is comparatively coherent and jet-like and is directed upwardly at a lesser angle to the vertical than an inner portion, and preferably vertically upwardly or substantially so i.e. within 20°, more preferably within 15° of the vertical. The inner (rearward) portion issues from an inlet arranged in such a way that it is directed diagonally inwardly and is turbulent so that it "plumes" comparatively close to the inlet, with the effect that the cold air instead of flowing over the displayed goods sinks onto them, due to the increased density of the cooled air, with virtually no lateral velocity, in the tank formed above the tray by it and front and rear side walls.

[0007] An outlet from the tank is provided at the top of its back wall and recirculation is through a common fan and evaporator into a plenum chamber at the front end of which the divided inlet is to be found.

[0008] The inner inlet will usually be choked and issue air at a lower velocity than the outer inlet; due to the difference the two portions tend to draw together thus lifting at least the upper edge of the inner portion and drawing the outer portion inwardly and backwardly so that the latter tends not to come into contact with the front wall of the cabinet. This may be a low wall to define the enclosure for the cold air. However in the preferred and most advantageous version the cabinet has a continuous transparent front wall up to a high level, and at an intermediate level and near the back of the cabinet there is an upper display shelf.

[0009] Previously, shelves above the base of the cabinet have either been uncooled, or if cooled have been so by means such as gravity coils at the top of the display which rely on the cold air falling onto the product below, firstly being deposited onto the shelf and then into the base of the cabinet and then, with the aid of a fan positioned at the front of the tray, being picked from the bottom of the cabinet and discharged in the general direction of the high level coil. This type of shelved delicatessen cabinet requires a rear mounted set of doors which is off-putting to the proposed end user as it restricts access to the product stored within the cabinet, and also produces a significant temperature difference between the shelf and the tray storage areas. Another problem seen with this type of cabinet is the lack of vision afforded by mounting an evaporator at high level and of putting a fan at the front of the tray.

[0010] We can in one aspect of this invention provide a "serve over" cabinet that encompasses the facility of a cooled storage shelf without the aforementioned restrictions.

[0011] In this aspect of the present invention, a shelf is provided towards the rear of the cabinet and intermediate the tray and the level of the top of a front wall; then the effect of the outer of the two portions of cooled air is that it will travel upwardly at the front portion of the cabinet to at or just above the level of the front of the shelf, it will there lose its upward velocity and start to fall so that it descends onto the shelf and ideally will spill gently over the back edge of the shelf as if over a weir and descend into the back portion of the tank which will be possible if the back end of the shelf is set forward of that. Thus materials on the shelf are cooled without high-velocity air being passed over them and without the need for cumbersome and unsightly cooling coils at the top of the cabinet and/or fans at the front of its tank.

[0012] It is envisaged that if the upper shelf were not in use, the fan motor of cabinets embodying the invention would be switched to a lower level so as to economise on power and so that the outer portion of the split air flow would instead of reaching the upper shelf simply assist in cooling of the goods on the tray. If the upper shelf were permanently absent clearly such a level of power could also be used.

[0013] In the accompanying drawings:

Figure 1 is a side view of a first embodiment of a cabinet;

Figure 2 is an enlargement of the front portion of the base of that cabinet; and

Figure 3 is a side view of a second embodiment.

[0014] In Figure 1 we see a delicatessen cabinet 1 in which a base structure 2 encloses a fan 3 and evaporator 4. It stands on legs 5 so as to dispose a display tray 6 at an angle of a few degrees to the horizontal, sloping downwardly towards a front wall 7 of the cabinet which is on the public access side. At the serving side 8 of the cabinet, a structural frame 9 extends upwardly through the base 2 to give support to an upper shelf 10 of the cabinet and a roof 11 which supports and mounts an upper end of a curved glass window 12 which encloses the front of the cabinet and meets with the front wall 7.

[0015] The serving side 8 of the cabinet, above a counter shelf 13 is open except for the frame 9.

[0016] At the front of the cabinet there is an air inlet into the display portion. This inlet is divided by a plate 14 seen in more detail in Figure 2.

[0017] The effect of this plate, together with an inner wall 15 of the front wall 7 and of an upturned end 16 of a support for the display tray 6, is to define two separate portions of the inlet. The outer inlet 17 directs air in a comparatively coherent portion, which is jet-like seen in side view, more-or-less vertically, and certainly at an angle which is greater to the horizontal than the output of the inner portion of the inlet 18, which is a flow of air of lower velocity and turbulent characteristics so that it remains in jet form for only a comparatively short distance, for example 6-8 cm, when it emerges from the inlet 18.

[0018] Air is supplied to the air inlets 17 and 18 from a plenum 19 formed within the base of the cabinet and within which the fan 3 and evaporator 4 are housed. An outlet 20 from the display volume is above a rear wall 21 of the display volume below the counter shelf 13. Arrows A,B show the flow of air from the display volume to the fan and evaporator (which are common to a given pair of flows through inlets 17,18) to the plenum 19 and thence to those inlets.

[0019] Figure 1 shows diagrammatically the passage of air in an outer coherent portion 22 from inlet 17 and a turbulent "plumed" portion 23 from the inner inlet 18.

[0020] Although the inlet 17 is substantially vertically disposed, the choking effect of the inlet 18 on the portion 23 means that it issues at a lower velocity than portion 22 and as is well known in the art this causes a curvature of the two with the effect that an upper part of the portion 23 is somewhat lifted and the portion 22 is drawn back into the display volume. This has the beneficial effect of keeping the coolest portion of the portion 22 somewhat spaced from the base portion of the glass wall 12, minimising problems of condensation on the outer surface of that wall. It is found that a comparatively closed circulation 24 of air is built up between the lower portion of the glass window and the jet formed by the portion 22.

[0021] Because the portion 23 plumes it has little or no lateral velocity when, due to its greater density than air of higher temperature, it tends to sink toward the base tray 6. In fact what has been formed is an essentially static pool of cooled air which sits on the products displayed on the tray 6.

[0022] Figure 3 shows how the construction of Figs. 1 and 2 may be used in a display cabinet which does not have the superstructure 9,10,11 or the front glass wall 12, but instead has slightly upwardly extended front wall 7', as shown at 25. Here however less power would be applied to driving the air in circulation and the portion 22 would fall lower so as to be drawn inwardly as before by the portion from the inner inlet 18 and be recirculated through outlet 20.

[0023] Turning back to Figure 1 however this shows how when the shelf 10 is present material displayed upon it is cooled by the air of portion 22. The power applied to the air and dimensioning of the output are such that air reaches to or just above the level of the shelf 10 before substantially losing its upward and rearward velocity so that the goods displayed on shelf 12 are cooled just like goods on tray 6 by a descending, rather than swiftly laterally moving, cooled air flow. Ideally, the arrangement will be such that there is a slight rearward movement over the shelf, which is preferably inclined a few degrees to the horizontal as illustrated in the Figure, so that cold air spills over the rear 26 of the shelf as indicated at 27 so that it is free to fall into the tank and be recirculated through outlet 20.

Claims

1. A cooling cabinet (1,1') having a display surface (6) for bearing goods to be cooled and an air cooling system (3,4) from which cooled air is supplied to the cabinet via inlet means (17,18) near a first side of the display surface such that air enters the cabinet near that second side in an inner turbulent stream (23) and an outer substantially coherent stream (22), which is directed at a smaller angle to the vertical than the inner stream.

2. A cooling cabinet according to claim 1 wherein there is an air outlet (20) near a second side of the display surface (6) opposite to the first through which air is withdrawn from the cabinet to the air cooling system.

3. A cooling cabinet according to claim 1 or claim 2 wherein the inlet is fed from a single air propeller (3).

4. A cooling cabinet according to claim 3 wherein the inlet is a single inlet divided (14) into a jet (17) to supply the coherent stream (22) and a choked portion (18) to supply the turbulent stream (23).

5. A cooling cabinet according to any one of the preceding claims having a shelf (10) located above the display surface and spaced from the first side.

6. A cooling cabinet (1') according to any of the preceding claims wherein the display surface is surrounded by walls (25), the cabinet having an open top.

7. A cooling cabinet according to any one of claims 1 to 5 having an inwardly curving wall (12) adjacent the first side of the display surface, the display surface being accessible from above its second side.

8. A method of operating a cooling cabinet (1,1') having a display surface (6), comprising providing cooled air at one side region of the display surface in an inner, angularly inwardly directed, turbulent stream (23) and an outer, substantially coherent stream (22), which is directed at a smaller angle to the vertical than the inner stream (23), such that ccol air (23) descends on to the display surface (6) from the inner stream with substantially no lateral velocity.

9. A method according to claim 8 including withdrawing air (20) from an opposite side of the display surface;

cooling said air (3,4); and

recycling the cooled air to the display surface.

10. A method according to claim 8 or claim 9 wherein the cabinet has a shelf (10) above the display surface and spaced from the said one edge region, the outer stream (22) but not the inner reaching the shelf (10).

11. A cooling cabinet according to claim 10, wherein the cool air from stream (22) descending on to the shelf (10) has some residual velocity, so as to spill off (27) the rear edge (26) of the shelf.

Drawing