GB2388185A

GB2388185A - Hot food storage and display cabinet

Info

Publication number: GB2388185A
Application number: GB0204283A
Authority: GB
Inventors: Andrew Dennis Kulka; David Berry
Original assignee: BARBECUE KING INTERNAT Ltd
Current assignee: BARBECUE KING INTERNAT Ltd
Priority date: 2002-02-23
Filing date: 2002-02-23
Publication date: 2003-11-05
Anticipated expiration: 2022-02-23
Also published as: GB2388185B; GB0204283D0

Abstract

A hot food cabinet 10 has a base 12 supporting a pair of conduits 36 each having a first part 37 receiving heated air, driven by a fan 40 through air heater 38, and delivering the heated air to a hot air entry port 42 64 in each of a plurality of hollow shelves 16, and a second part 44 for receiving cooled air from the hollow shelves 16 through a hot air exit port 46 66 and returning the cooled air to the air heater 38 40, the air moving in a closed, recirculating path. Heated air is introduced into the hollow shelves through a duct (70, fig 4b) preferably beneath a baffle (54, fig 4b) the heated air being distributed over the thermally conductive upper surface of the hollow shelves 16. Food items (26 28 30, fig 1) are placeable on the heated upper surface of each shelf 16. The shelves 16 are preferably provided in an open fronted cabinet 10 having an open front 24 for retrieval of food items 26 28 30, protective sides 22 for preventing loss of heated air, and preferably an air curtain 34 80 82 84 where a blower 80 collects air at the top 82 of the open front 24 and blows the collected air, from the bottom 34 of the open front 24, upwards across the open front 24. Thermally conductive packaging 30 may be used, which can be placed upon the heated shelves 16, can be used to contain food 26 28 30 to be kept clean and warm.

Description

23881 85

HOT CABINET

The present invention relates to devices for the storage or display of hot food. It particularly relates to cabinets where hot food can 5 be offered for sale or selection in, for example, shops, supermarkets, canteens and cafeteria.

The sale of hot food poses many problems. For example, the food, once heated, has to be maintained above a critical temperature 10 (around seventy degrees Celsius) to maintain sterility. Prior art

solutions provide that hot food can be stored in closing cabinets, which a customer had to open before access to the food can be achieved. By contrast, the present invention offers a solution where hot food can be freely accessed without opening a cabinet.

Free access to hot food has usually meant the provision of a "hot counter" with shields to prevent respiratory and other customer detritus from contaminating the food and also requiring the presence of attendant staff to retrieve food items for the 20 customer. The present invention offers a solution where free customer access is achieved without the need for shields or attending staff.

Prior art maintenance of hot food temperature requires much heat.

25 Prior art solutions are mainly electric. The large amounts of heat

required means that expensive three phase electricity supplies have to be installed, limiting the moveabilty of the equipment and significantly increasing its price. By contrast, the present invention offers a hot food storage and display apparatus that can 30 provide a copious display area using the power readily available from a simple domestic style electrical outlet socket, and is cheap to install and readily moveable.

The large amount of heat lost into the immediate environment by 35 prior art hot food display apparatus challenges the capacities of

in-store air conditioning systems. By contrast, the present invention offers a solution which is extremely conservative of heat

and which does not offer any significant challenge to in-store air conditioning systems.

According to a first aspect, the present invention consists in an 5 apparatus for the storage and display of hot food, said apparatus comprising: a conduit for movement of a gas; means to heat the gash means to pump the gash and a hollow shelf for supporting food, the face to be presented to the food being thermally conductive; where said hollow shelf and said conduit are co-operative to provide a 10 recirculating closed path around which the heated gas is pumpable through said heating means, into said hollow shelf, and back to said heating means.

According to a second aspect, the present invention consists in a 15 method for storage and display of hot food, said method including the steps of: pumping a gas in a recirculating closed path through heating means, into a hollow shelf, and back to said heating means; and providing that the face of said hollow shelf, to which food is to be presented, is thermally conductive.

20! The invention further provides that the hollow shelf can comprise; an internal baffle for distribution of heated gas onto said face of said hollow shelf.

25 The invention further provides that the hollow shelf can comprise a duct for directing heated gas to a region proximate to the edge of said baffle furthest from the point of entry of heated gas into said hollow shelf.

30 The invention further provides that the duct can direct heated gas to a selectable region along the width of the baffle.

The invention further provides that the duct can be one of a plurality of ducts.

The invention further provides that the hollow shelf can be one of a plurality of shelves.

The invention further provides that the plurality of shelves can be arrayed one above another, each shelf having one or more heated gas entry ports for receiving heated gas from said conduit and one or more gas exit ports for returning gas to said conduit.

The invention further provides that the conduit can comprise a first part for receiving heated gas from the heating means and sending it to the entry ports or ports of said shelves or shelves, and a second part for receiving gas from the exit port or ports of 10 said shelf or shelves and returning it to the heating means.

The invention further provides that the conduit can serve as a support for said shelf or shelves.

15 The invention further provides that said conduit can one of a plurality of conduits.

The invention further provides that said shelves can be arranged as an open fronted cabinet with an open front to allow access to hot 20 food and protective sides to prevent loss of heated air.

The invention further provides that said cabinet can comprise a rising air curtain on said open front.

25 The invention further provides that the rising air curtain can comprise a blower to blow air from a slot, proximate to the lower edge of said open front and to collect air from proximately to the upper edge of said open front.

30 The invention further provides that the gas can be air.

The invention further provides that the heating means can be a fan.

The invention further provides that the heating means can comprise 35 an electric element.

( The invention further provides that hot food is containable within packaging, that the packaging can conduct heat, and that the packaging can be placed in contact with said shelf or shelves.

5 The invention is further explained, by way of example, by the following description, read in conjunction with the appended

drawings, in which: Figure l is an isometric view of a cabinet for hot food storage lo incorporating the present invention.

Figure 2A and Figure 2B are sectional views of the hot food shelf storage system, with closed recirculating heated air, shown in Figure 1.

Figure 3 is a disassembled view illustrating how a hot shelf can be attached to the conduit system otherwise visible in Figures 2A and 2B. 20 Figures 4A and 4B are, respectively, top and angled transparent views illustrating how a duct is used to distribute hot air within a heated shelf.

And Figure S is a cross sectional view of the cabinet of Figure 1 showing how the reverse air curtain protects the open front of the cabinet from excessive heat loss.

30 Attention is first drawn to Figure 1, showing an isometric view of a hot food storage cabinet according to the present invention.

The cabinet 10 comprises a base 12 which supports a food storage and display area 19. Heated hollow shelves 16 are supported from 35 behind and have slightly tilted upper surfaces 18 which tend to urge food towards the front of the shelf. This assists in avoiding individuals burning themselves while reaching across a shelf 16.

Transparent edges 20 prevent the food from falling from the shelf

( 16. The manner in which the shelves 16 are kept hot is explained hereafter. The base 12 also supports protective sides 22 which abut or are closely disposed to the ends of the shelves 16. The cabinet 10 has an open front 24 through which a user can reach to 5 gain access to food items 26, 28. Some food items 26 can rest directly on the upper surface 18 of a shelf 16. Other food items 28 can be held within closed containers 30 which derive their internal heat by at least the lower surface of the container 30 being thermally conductive, which provides a microclimate within 10 the container 30 for maintaining the temperature of the hot food, and which provides further protection from contamination.

A recirculating, rising air curtain has a lower vent 34 stretching substantially across the width of the lower edge of the open front Is 24. As will later be described, air is pumped from the lower vent 34 up the open front 29 to help maintain the thermal integrity of the food storage and display area 14 and to divert any airborne contamination. 20 Attention is drawn to Figures 2A and 2B. Figure 2A shows a side view (partially transparent) of a conduit 36 used in the closed recirculating hot air system of the present invention and Figure 2B shows a partially open side view of the assembled shelves 16 on the conduit 36.

Attention is drawn to Figure 2A. The conduit 36 comprises a first part 37 adapted to send heated air from heating means in the form of an electric heating element 38, driven by pumping means in the form of an electrically driven fan 40. The hot air is delivered to 30 the hollow heated shelves 16 through hot air entry ports 42.

The conduit 36 also comprises a second part 44 for receiving, from the shelves 16, formerly hot air which has circulated within the shelves 16. The exhausted air is received through exit ports 46 35 and conducted back to the electrically heated element 38. The flow from the electrically heated element 38 is indicated by arrows 48, the flow towards the electrically heated element 38 is indicated by arrows 50, and the transfer of air between the first part 37 and

the second part 44, which are joined at the base of the conduit 36 by the fan 40, is indicated by arrow 52. The first part 37 and the second part 44 of the conduit 36 are shown in close proximity to each other, being separated by a single wall 54. As will become 5 apparent, the first part 37 and the second part 44 of the conduit 36 can be separated from one another. The fan 40 is shown in proximity with the electrically heated element 38. It is to be appreciated that the fan 40 can be anywhere within the first part 37 or the second part 44 of the conduit 36, and there can be more 10 than one fan. It is preferred that the electrically heating element 38 is at the bottom of the conduit 36 because hot air naturally rises, assisting circulation. However, it is to be appreciated that the electrically heated element 38 could be at any point within the conduit 36. All that is required is that air can 15 circulate within the conduit 36.

Attention is drawn to Figure 2B showing a side view of the closed, recirculating hot air system of Figure 1. The second part 44 of the conduit 36 is shown with its side removed, the better to reveal 20 the flow of heated air. Each shelf 16 comprises a baffle 54 which divides each shelf 16 into a lower portion 56 through which heated air enters from the first part 37 of the conduit 36, and an upper portion 58 which returns air to the second part 44 of the conduit 36. The baffle 54 stretches across the full width of the shelf 16 25 but leaves a gap between its tip end 60 and the upper surface 18 of the shelf 16 so that heated air may progress from the lower portion 56 to the upper portion 58 of the shelf 16. The flow of heated air is indicated by arrows 62.

30 Attention is next drawn to Figure 3, showing how the two conduits 36, in this example, are mirror images of each other. On one conduit the hot air entry port 42 is on the right hand side, as viewed from the shelf, while the other conduit 36 has its hot air entry port on the left hand side. The exit ports 46 are, on one 35 conduit 36, on the left hand side, and on the other conduit 36, on the right hand side. The first part 37 and second part 44 also display the mirror image property. While this mirror image

property is preferred, it is apparent that conduits 36 that are not mirror images can also be employed.

The shelf 16 is shown in transparent view, the better to clarify the manner of attachment and operation. One adjacent set of exit 5 ports 46 and entry ports 42 define the level on the conduits 36 that a shelf 16 can be attached. The upper portion 58 of the shelf 16 bears a shelf exit port 66. There is one shelf exit port 66 at either end of the shelf 16. The lower portion 56 of the shelf 16 comprises a shelf entry port 64. There is one shelf entry port 64 10 at either end of the shelf 16. When the shelf 16 is brought into engagement with the conduits 36, as indicated by arrow 68, at any particular level, the shelf entry ports 64 engage and cover the hot air entry ports 42 on the conduits 36, and the shelf exit port 66 engages and covers the exit ports 46 on the conduits 36. Only one 15 shelf is shown. The present invention envisages that only one shelf may be present. The present invention also envisages that the conduits 36 may have a capacity for only one shelf 16, or more than one shelf 16. If the conduits 36 have a capacity for more than the number of shelves 16 present, it is envisaged that plugs 20 be provided to block off any unused exit ports 46 or entry ports 42 on the conduits 36. When assemble with its shelf 16 or shelves 16, the conduits 36 and the shelves 16 form a closed system, from which ingress or egress of air is substantially eliminated, capable of circulating hot air over the underside of the upper surface 18 or 25 surfaces 18 of the shelf 16 or shelves and returning the still substantially warm air to be reheated.

The shelves 16 may be attached to the conduits in various different ways. They may be demountably attached so that the shelf 16 may be 30 removed from the conduits 36 for cleaning or repair. This can include, but is not limited to, use of gravity, hooks, conformally fitting parts, screws or clamps. Alternatively, the shelf 16 may be permanently attached by means which can include, but is not limited to, welding and glueing. All that the invention requires is 35 that the means of attachment of the shelf 16 or shelves forms a substantial seal with the conduit 36 or conduits 36.

( Attention is next drawn to Figures 4A and 4B, which show how heated air is directed within a shelf 16. Figure 4A and Figure 4B are described together. Figure 4A shows a plan view from above of a shelf 16 with semitransparency, and Figure 4B is a cutaway 5 isometric view of one end of a shelf 16.

The shelf 16 comprises a pair of ducts 72 which lead from the shelf entry port 64 to close to the tip edge 60 of the baffle 54. While this embodiment shows the duct being coincident with the tip edge 10 60 of the baffle 54, it is to be appreciated that the duct 72 may terminate slightly before or slightly after the tip edge 60 of the baffle 54. In Figure 4A the duct is shown in broken outline as it lies completely beneath the baffle 54. Air flow is described by three sets of arrows. Lower arrows 72 show the flow of air beneath 15 the baffle 54. Transition arrows 74 show the air coming from below the baffle 54 onto the top of the baffle 54. Upper arrows 76 show the flow of air above the baffle 54.

The tip edge 60 of the baffle 54 is a very small distance, or the 20 order of 5mm, from the underside of the upper surface 18 of the shelf 16. Because of this close spacing, the underside of the upper surface 18 forces the air, trapped beyond the tip edge 60, to spread out across the width of the shelf 16 along the tip edge 60 of the baffle 54 as it tries to enter the gap between the tip edge 25 60 and the underside of the upper surface 18 of the shelf 16.

Isothermal contour 78, also shown in dotted outline, show a typical example of the spread of temperature across the outside of an upper surface 18 of a shelf 16 from each duct 72. Heated air is spread across the entire width of the underside of the upper surface 18 of 30 the shelf 16. There are no cold areas. The isothermal contour 78 shown simply illustrates the edge of an area or areas which is or are above the required temperature for operation of the shelf 16.

The ducts 72, in this example, deliver their warm air approximately 35 one-quarter the distance from the side of a shelf 16. It is to be appreciated that other distances can be used. It is also to be appreciated that only one duct 72 can be used with a single shelf entry port 64 and a single shelf exit port 66. It is also to be

( appreciated that more than two ducts 72 can be used for wide shelves 16, there then being more than two sets of shelf entry ports 64 and shelf exit ports 66. It is also to be appreciated that the baffle 54 can be made adjustable so that the gap between 5 the tip end 60 of the baffle 54 and the underside of the upper surface 18 can be altered to obtain different, better or worse isothermal contours 78. The speed of turning of the fan 40 or the pitch of its blades can be adjustable as a means of altering the shelf 16 temperature. Adjustable baffles can be placed in the 10 conduit 36 to alter the rate of air flow to alter the shelf 16 temperature. These measures can be used individually, severally or all together. The heating element 38 may also be thermostatically controlled. The regulating thermostat may be situated in a shelf 16, or in a conduit 36. The temperature control can be on an on-off IS basis, or can be a continuous control where the amount of heat, delivered by the heating element 38, is altered by means of controlling the amount of electrical current passing there-through.

20 In this example, the conduits 36 and the shelves 16 are made from sheet metal. The invention envisages that the only surface anywhere in the closed cycle warming mechanism that needs to be thermally conducted, is the upper surface 18 of a shelf 16. The conduits 36 can be made from thermally non-conducting material, or 25 can be insulated to prevent heat loss. The shelves 16 may have the upper surface 18 made from thin conducting material such as thin sheet metal, while the other parts are made from thicker metal or non-conducting material. Equally, those parts of a shelf 16 which are not the upper surface 18 can be insulated. These measure can 30 also be used individually, severally, or all together.

Attention is drawn to Figure 5, being a cross-sectional view of a cabinet 10 illustrating how the rising air curtain is created.

35 The conduits 36 and shelves 16 are sealed from the internal parts of the cabinet 10 to provide a pleasant and safe environment for customers and other users. Inside the cabinet 10 a blower 80 sucks air through a honeycomb filter 82, around an internal hose or duct

( 84 as indicated by arrows 86, and blows it out again through the lower vent 34. This creates a curtain of rising air, moving as indicated by arrows 88 from the bottom of the open front 24 to the top of the open front 24. Heated air, from the shelves 16, is 5 drawn into the honeycomb filter 82 and returned, still reasonably warm, to the bottom of the Open front 24 through the lower vent 34.

The invention envisages that the honeycomb filter 82 can cover more or less of the upper inner surface 90 of the cabinet lo and that the honeycomb filter 82 may be anything from a simple duct to 10 highly complex biological filters, if required.

The invention permits that the body of the cabinet 10 can serve as the duct or hose 84, and that the blower 80 can be situated other that where shown within or without the cabinet 10. All that the 15 present invention requires is that a rising air curtain is provided for the open front 24 by means of air circulation, and that the-

returned air, through the hose or duct 84, a reasonable degree of thermal insulation whilst in the hose or duct 84.

Claims

( CLAIMS

1. An apparatus for the storage and display of hot food, said apparatus comprising: a conduit for movement of a gas; heating means 5 to heat the gas; pumping means to pump the gas; and a hollow shelf for supporting food, the face of said hollow shelf to be presented to the food being thermally conductive; where said hollow shelf and said conduit are cooperative to provide a recirculating closed path around which the heated gas is pumpable through said heating means, 10 into said hollow shelf, and back to said heating means 2. An apparatus, according to claim 1, wherein said hollow shelf comprises an internal baffle for distribution of heated gas onto said face of said hollow shelf to be presented to the food.

3. An apparatus, according to claim 2, wherein said hollow shelf comprises a duct for directing heated gas to a region proximate to the edge of said baffle furthest from the point of entry of heated gas into said hollow shelf.

4. An apparatus, according to claim 3, wherein said duct is operative to direct heated gas to a selectable region along the width of said baffle.

25 5. An apparatus, according to claim 3 or claim 4, wherein said duct is one of a plurality of ducts.

6. An apparatus, according to any one of the preceding claims, wherein said hollow shelf is one of a plurality of hollow 30 shelves.

7. An apparatus, according to claim 6, wherein said plurality of hollow shelves are arrayed one above another, each of said plurality of hollow shelves comprising one or more heated gas entry 35 ports for receiving heated gas from said conduit and one or more gas exit ports for returning gas to said conduit.

8. An apparatus, according to any one of the preceding claims, wherein said conduit comprises a first part for receiving heated gas from the heating means and sending it to the entry port or ports of said hollow shelf or hollow shelves, and a second part 5 for receiving gas from the exit port or ports of said shelf or shelves and returning the gas to the heating means.

9. An apparatus, according to any one of the preceding claims, wherein said conduit further provides support for said 10 hollow shelf or hollow shelves.

lo. An apparatus, according to any one of the preceding claims, wherein said conduit is one of a plurality of conduits.

15 11. An apparatus, according to any one of the preceding claims, comprising an open fronted cabinet, said hollow shelf or hollow shelves being provided in said open fronted cabinet, said open fronted cabinet comprising an open front to allow access to hot food, and said open fronted cabinet further comprising protective 20 sides to prevent loss of heated air.

12. An apparatus, according to claim 11, wherein said open fronted cabinet comprises a rising air curtain on said open front.

25 13. An apparatus, according to claim 12, wherein said rising air curtain comprises a blower to blow air from a slot, proximate to the lower edge of said open front and to collect air from proximately to the upper edge of said open front.

30 19. An apparatus, according to any one of the preceding claims, wherein said gas is air.

15. An apparatus, according to any one of the preceding claims, wherein said heating means comprises a fan and an electric element 16. An apparatus, according to any one of the preceding claims, comprising packaging for containing food, the packaging

being thermally conductive, and the packaging being placed in thermal contact with said hollow shelf.

17. A method for storage and display of hot food, said method 5 including the steps of: pumping a gas, in a conduit, in a recirculating closed path through heating means, into a hollow shelf, and back to said heating means; and providing that the face of said hollow shelf, to which food is to be presented, is thermally conductive. 18. A method, according to claim 17, including the step of providing said hollow shelf with an internal baffle for distribution of heated gas onto said face of said hollow shelf to be presented to the food.

19. A method, according to claim 18, including the step of providing said hollow shelf with a duct for directing heated gas to a region proximate to the edge of said internal baffle furthest from the point of entry of heated gas into said hollow shelf.

20. A method, according to claim 15, including the step of providing that said duct is operative to direct heated gas to a selectable region along the width of said baffle.

25 21. A method, according to claim 19 or claim 20, for use where said duct is one of a plurality of ducts.

22. A method, according to any one of claims 17 to 21, for use where said hollow shelf is one of a plurality of hollow 30 shelves.

23. A method, according to claim 22, including the steps of: arranging said plurality of hollow shelves one above another; providing each of said plurality of hollow shelves with one or more 35 heated gas entry ports for receiving heated gas from said conduit; and providing each of said plurality of hollow shelves with one or more gas exit ports for returning gas to said conduit.

29. A method, according to any one of the preceding claims, including the steps of: providing, in said conduit, a first part for receiving heated gas from the heating means and sending it to the 5 entry port or ports of said hollow shelf or hollow shelves; and providing, in said conduit, a second part for receiving gas from the exit port or ports of said shelf or shelves and returning the gas to the heating means.

10 25. A method, according to any one of claims 17 tp 24, including the step of employing said conduit as a support for said hollow shelf or hollow shelves.

26. A method, according to any one of claims 17 to 25, for use 15 where said conduit is one of a plurality of conduits.

27. A method, according to any one of claims 17 to 26, including the steps of: providing an open fronted cabinet; providing said hollow shelf or hollow shelves in said open fronted cabinet; 20 providing an open front in said open fronted cabinet to allow access to hot food; and providing said open fronted cabinet with protective sides to prevent loss of heated air.

28. A method, according to claim 27, including the step of 25 providing said open fronted cabinet with a rising air curtain on; said open front.

29. A method, according to claim 28, including the step of providing said rising air curtain in the form of a blower, causing 30 said blower to blow air from a slot, proximate to the lower edge of said open front, and causing said blower to collect air from proximately to the upper edge of said open front.

30. A method, according to any one of claims 17 to 29, wherein 35 said gas is air.

31. A method, according to any one of claims 17 to 30, including the step of providing, as said heating means, a fan and an electric heating element.

5 32. A method, according to any one of claims 17 to 31, including the steps of: providing packaging for containing food; providing that said packaging is thermally conductive; and allowing for placing of said packaging in thermal contact with said hollow shelf.