GB2466989A

GB2466989A - A hot food storage unit

Info

Publication number: GB2466989A
Application number: GB0900802A
Authority: GB
Inventors: Kenneth Thomas Stewart; Colin William Stewart; Keith Anthony Stewart
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-01-19
Filing date: 2009-01-19
Publication date: 2010-07-21
Anticipated expiration: 2029-01-19
Also published as: GB0900802D0; GB2466989B

Abstract

A hot food storage unit comprises a cabinet 3 having a food storage compartment 5, a heating compartment 7, a transparent display shield 9 covering the food in the food storage compartment and an opening 11 in the display shield adjacent to the rear of the cabinet to allow access to the food in the food storage compartment. The hot food storage unit has a pair of primary heating units 30 each comprising a tangential fan 19 and a heating coil and a secondary heating unit mounted intermediate the primary heating units. The secondary heating unit includes an evaporator. In this way, the compact unit is able to provide relatively uniform heat distribution throughout the food storage compartment with different amounts of moisture in different areas of the cabinet. This is achieved without extensive partitioning in the food storage compartment.

Description

"A hot food storage unit"

Introduction

This invention relates to a hot food storage unit of the type comprising a cabinet having a food storage compartment, a heating compartment, a transparent display shield covering the food in the food storage compartment and an opening in the protective shield to allow access to the food in the food storage compartment.

Hot food storage units are commonly found in convenience stores and similar outlets where hot food is pre-prepared and sold over the counter to customers.

The food is stored at a suitable temperature in the hot food storage unit. Various different constructions of hot food storage units have been proposed. However, there are problems with the known types of hot food storage units.

Many of the hot food storage units provide heated air as the sole means of keeping the food at an acceptable temperature. FR2859085 discloses a hot food storage cabinet in which a tangential fan is used to draw air in through an air inlet, pass that air over a heating element and then force the air through a heated air duct and out of the air duct at the top of the cabinet. The heated air forms a curtain of hot air that passes between the food on shelves in the cabinet and the front of the cabinet before entering the air inlet for recirculation. Although effective at keeping the food hot, these units are limited in the foods that they can store as hot air alone will dry out many foods in a relatively short period of time rendering the food unpalatable.

In order to overcome this problem, some hot food storage units are also provided with an evaporator to provide moisture to the heated air. FR2859086 discloses a hot food storage cabinet having a display compartment and a heating unit comprising a heating coil and a moisturiser. Air is drawn in through an air inlet by a tangential fan and is then in turn passed over the heating coil and the moisturiser before being delivered out through an air outlet to pass over the food.

US5595109 discloses a food storage unit that has a pair of heating units, an air heating unit and an evaporator. The pair of heating units are used together to heat food in the unit. A tangential fan is used to circulate air in the air heating unit.

US6157006 discloses another embodiment of food storage unit that has a pair of heater units, an air heating unit and an evaporator unit. FR2850261 discloses a hot food storage unit having fans for circulating hot air and tanks for saturating the hot air with steam. DE29800105 discloses a hot food storage cabinet having a pair of heating units, a heating coil and an evaporator unit.

Although the food in the units that provide a moist, heated air supply, will not dry out as quickly compared with units that provide heated air alone, there are also problems with these units. These units are also limited in the foodstuffs that they can store as some foodstuffs will become too moist in the environment created in the unit rendering them unpalatable.

Various food storage units have been proposed that attempt to separate the cabinet into a plurality of zones to store different foodstuffs. One such example is that described in US2003/O1 08647. US2003101 08647 discloses a food storage unit that may be used for storage of both hot and cold foodstuffs at the same time. A divider is provided to segment the unit into hot storage compartments and cold storage compartments. This unit has a relatively complex arrangement for providing different hot and cold zones and the structure is not particularly suitable for displaying foodstuffs in a retail environment. Furthermore, US2003/0108647 is not concerned with the levels of moisture in the different zones of the cabinet.

WO01/47397 discloses a hot food storage unit similar in construction to the present invention. The unit has a bed for placement of food thereon and a plurality of separate heaters below the bed to allow different parts of the bed to be heated separately thereby dividing the bed into zones. In this way, energy is not wasted heating a part of the bed that is not in use. WO01/47397 does not discuss the use of an evaporator and does not provide zones of differing moisture levels.

US5626028 discloses a food storage cabinet that may comprise any combination of a hot food storage unit, a cold food storage unit and an ambient food storage unit. The object is to provide a modular assembly that can be used to construct counters having a combination of the three zones in a single continuous cabinet structure and at the same time allow the precise size of cabinet zones to be varied.

US5626028 does not discuss having different moisture levels in the different areas.

Furthermore, US5626028 has a relatively complex arrangement to separate the various zones resulting in a complex construction that is more difficult to clean.

EP1460358 discloses a food storage unit that provides a plurality of different zones each with different environmental conditions therein. The environmental conditions may simply be different temperature, i.e. hot and cold zones, or may be different humidity levels. This is achieved by supplying conditioned air to a zone through the shelf unit delineating the zone. The design of cabinet disclosed in EP14060358 is relatively complex with intricate channels for providing the different conditioned air to the different zones that would be complex to manufacture and difficult to clean.

It is an object therefore of the present invention to provide a hot food storage unit that overcomes at least some of the problems with the known units that is relatively simple to manufacture and maintain.

Statements of Invention

According to the invention there is provided a hot food storage unit of the type comprising: a cabinet having a food storage compartment, a heating compartment, a transparent display shield covering the food in the food storage compartment and an opening in the display shield adjacent the rear of the cabinet to allow access to the food in the food storage compartment, in which:-the food storage compartment comprises a compartment floor for reception of food in containers; the heating compartment is located substantially below the food storage compartment and comprises a plurality of primary heating units, a secondary heating unit, an air circulation duct and a plurality of fan units; the air circulation duct further comprising an air charging inlet located adjacent the rear of the cabinet in fluid communication with both the air circulation duct and the food storage compartment, and an air discharge outlet located adjacent the front of the cabinet in fluid communication with both the air circulation duct and the food storage compartment; the fan units each comprising a tangential fan, mounted in the air circulation duct adjacent the air charging inlet at the rear of the cabinet, and spaced apart laterally from each other in the cabinet, one of the tangential fans being mounted adjacent one side of the cabinet and the other tangential fan being mounted remote from the first tangential fan adjacent the other side of the cabinet, the tangential fans being operable to circulate air in the cabinet by drawing air into the air circulation duct of the heating compartment from the food storage compartment through the air charging inlet, driving the air along the air circulation duct and forcing the air out of the heating compartment to the food storage compartment through the air discharge outlet before drawing the air back in through the air charging inlet; the primary heating units each comprising a heating coil mounted in the air passageway located adjacent to the tangential fan and on the side of the tangential fan remote from the air inlet, the heating coil extending forwardly from the rear of the cabinet towards the front of the cabinet, one of the primary heating units being mounted adjacent one side of the cabinet and the other primary heating unit being mounted remote from the first primary heating unit adjacent the other side of the cabinet; the secondary heating unit comprising an evaporator, the evaporator comprising a liquid reservoir mounted above a secondary heating coil, the secondary heating coil extending forwardly from the rear of the cabinet towards the front of the cabinet and in which there is provided a liquid charging inlet in communication with the liquid reservoir of the evaporator and accessible from the rear of the cabinet so that liquid can be poured into the liquid reservoir from the rear of the cabinet; and the secondary heating unit is mounted in the air circulation duct intermediate the pair of adjacent heating coils of the primary heating units, thereby dividing the food storage compartment into a plurality of zones of varying moisture levels, a moist zone located centrally in the cabinet above the evaporator sandwiched between a pair of dry zones either side of the moist zone and located to the sides of the cabinet.

By having such a hot food storage unit, the cabinet will be able to store a wide range of foodstuffs. This is due to the fact that the configuration of cabinet, heating units and tangential fans will provide a moist zone in the food storage compartment located above the evaporator and a pair of substantially dry zones either side of the moist zone created by the heated air emanating from the primary heating units. Foodstuffs that require a significant amount of moisture, for example cooked chicken, can be placed in the central moist zone whereas other foodstuffs requiring less moisture, for example sausages, can be placed in one of the dry zones either side of the moist zone. The location of the different zones is closely controlled by the specific configuration of the hot food storage unit. This will enable different foodstuffs to be stored in the same cabinet and will not require different cabinets for different foodstuffs. Advantageously, the cabinet does not have a multitude of partitions in the interior food storage compartment thereby facilitating cleaning of the food storage compartment and facilitating serving of foodstuffs from the different zones in the cabinet. The reduced construction complexity will reduce the cost of manufacture and maintenance of the cabinet.

In one embodiment of the invention there is provided a hot food storage unit in which the liquid reservoir has a casing and in which the casing and one of the side walls of the cabinet form an isolated heated air channel in the air circulation duct and the casing and the other side wall of the cabinet form another isolated heated air channel in the air circulation duct. This will help provide more defined moist and dry zones in the cabinet.

In a further embodiment of the invention, the air charging inlet is provided with a plurality of apertures across the width of the cabinet, and in which one of the number and the size of the apertures is varied across the width of the cabinet to provide a uniform flow of hot air across the food in the food storage compartment.

In one embodiment of the invention, there is a greater density of apertures in areas of the air charging inlet remote from the tangential fans than in areas adjacent to the tangential fans.

In one embodiment of the invention, the air discharge outlet is provided with a plurality of apertures across the width of the cabinet, and in which one of the number and the size of the apertures is varied across the width of the cabinet to provide a uniform flow of hot air across the food in the food storage compartment.

In another embodiment of the invention, the secondary heating unit comprises a pair of independently operable secondary heating coils, mounted in the casing constructed from a conductive material beneath the liquid reservoir.

In a further embodiment of the invention, one of the independently operable coils of the secondary heating unit has a power rating of the order of one half the power rating of the other independently operable coil in the secondary heating unit.

In one embodiment of the invention, the air charging inlet has a raised lip to prevent ingress of food into the heating compartment from the food storage compartment.

Detailed Description of the Invention

The invention will now be more clearly understood from the following description of some embodiments thereof giving by way of example only with reference to the accompanying drawings in which:-Fig. 1 is a cross-sectional view of a hot food storage unit according to the present invention; Fig. 2 is a cross-sectional view of the hot food storage unit, similar to Figure 1 with the casing of the secondary heating unit removed; Fig. 3 is a perspective view of a front vent and a rear vent; Fig. 4 is an enlarged perspective view of the front vent shown in Figure 3; Fig. 5 is an enlarged perspective view of the rear vent shown in Figure 3; Fig. 6 is a plan view of the hot food storage unit with the shield and food storage compartment floor removed; Fig. 7 is a plan view of the hot food storage unit with the shield, food storage compartment floor and liquid reservoir and casing of the evaporator removed; Fig. 8 is a perspective view of a second embodiment of front vent for use in the hot food storage unit according to the present invention; Fig. 9 is a perspective view of a second embodiment of rear vent for use in the hot food storage unit according to the present invention; Fig. 10 is a perspective view of a third embodiment of rear vent for use in the hot food storage unit according to the present invention; Referring to the drawings and initially to Figs. 1 and 2 thereof, there is shown a hot food storage unit, indicated generally by the reference numeral 1 comprising a cabinet 3 having a food storage compartment 5 and a heating compartment 7. The cabinet 3 comprises a transparent display shield 9 having an opening 11 therein to provide access to the food in the food storage compartment 5. The food storage compartment 5 comprises a floor 13 for reception of food in containers 15. The heating compartment 7 in turn comprises a plurality of primary heating units 30, a secondary heating unit 31, an air circulation duct 21 and a plurality of fan units 19.

The air circulation duct 21 further comprises an air charging inlet 27 located adjacent the rear 29 of the cabinet 3 in fluid communication with both the air circulation duct 21 and the food storage compartment 5, and an air discharge outlet 23 located adjacent the front 25 of the cabinet 3 in fluid communication with both the air circulation duct and the food storage compartment 5. The fan units 19 each comprise a tangential fan, mounted in the air circulation duct 21 adjacent the air S charging inlet 27 at the rear 29 of the cabinet 3. The tangential fans operate to circulate air in the cabinet 3 by drawing air in through the air charging inlet 27, forcing the air along the air circulation duct 21 and out of the air discharge outlet 23 before drawing air back in through the air charging inlet 27. In this way, hot air is circulated across the food in the containers 15.

The primary heating units 30 each comprise a heating coil mounted in the air circulation duct 21 located adjacent to the tangential fan 19 and on the side of the tangential fan 19 remote from the air charging inlet 27. The heating coil 30 extends forwardly from the rear of the cabinet towards the front of the cabinet. The secondary heating unit 31 is also mounted in the air circulation duct intermediate the pair of adjacent primary heating units 30 and is located substantially centrally across the width of the cabinet 3. The secondary heating unit 31 comprises an evaporator 40, the evaporator comprising a liquid reservoir 41 mounted above a secondary heating coil 31. The secondary heating coil extends forwardly from the rear of the cabinet 3 towards the front of the cabinet. A liquid charging inlet 32 is provided which is in communication with the liquid reservoir of the evaporator and accessible from the rear 29 of the cabinet 3 so that liquid can be poured into the liquid reservoir from the rear of the cabinet.

By having the evaporator positioned centrally with the two primary heating unit's heating coils located on either side of the evaporator, the cabinet will have a plurality of zones, a moist zone in the centre above the evaporator and a pair of dry zones, one located on either side of the moist zone above the primary heating coils. This will enable foodstuffs having different heating requirements to be stored in the one cabinet and maintained in an acceptable, palatable condition. The segmentation of the cabinet is achieved using a very simple construction that will be relatively inexpensive to manufacture and does not require complex channelling arrangements to channel air of different moisture content to the different zones. Furthermore, by having the arrangement shown, it is not necessary to have dividers in the food storage compartment which dividers can slow down the serving of foodstuffs from the cabinet and increase the amount of time and effort required to clean the cabinet.

Referring to Figs. 3 to 5 inclusive of the drawings, there is shown a perspective view of the air charging inlet 27 and air discharge outlet 23. The air charging inlet 27 is provided in a rear vent 37 which is mounted above the tangential fans. The air discharge outlet 23 comprises a plurality of obround apertures equi-spaced along the length of a front vent 35. The apertures of the air charging inlet 27 are also obround apertures. The apertures are approximately 50mm in length, 5 mm in width and spaced apart from each other by approximately 3 mm. Referring specifically to Fig. there is shown an enlarged view of the rear vent 37 which comprises a downwardly depending lip 49 mounted above the apertures of the air charging inlet 27.

Referring to Fig. 6 of the drawings, there is shown a plan view of the hot food storage unit according to the present invention. There is shown a pair of primary heating unit heating coils 30 mounted either side of a secondary heating unit, in this case an evaporator. The evaporator comprises a liquid reservoir 41 which in turn comprises a pair of liquid channels 42, 43 mounted either side of a divider 44. Water is placed in each of the channels 42, 43 in the reservoir 41 which is heated up to the order of 60°C and steam is generated to heat the food in the compartment. The heating coils on either side of the secondary heating unit 31 are also used along with air flow generated to heat the food above.

The air flow over each of the heating coils 30 from the tangential fans (not shown) is channelled between the side wall of the cabinet and the secondary heating unit casing in an isolated heated air channel. The tangential fans provide a strong directional flow of air over the heating coils. Together, these provide concentrated flows of dry air over the food in the cabinet either side of the secondary heating unit 31. This has the effect of segregating the cabinet into the plurality of dry and moist zones.

Referring to Fig. 7 of the drawings, there is shown a plan view similar to that shown in Fig. 6 with the liquid reservoir 41 and casing removed to expose a pair of secondary heating coils 45, 47. The heating coil 45 is a 300 watt heating coil and the heating -10 -coil 47 is a 600 watt heating coil and they are independently operable with respect to each other. Therefore, depending on the amount of heat required and the amount of steam required, one or both of the heating coils 45, 47 may be put in operation to heat the liquid in the liquid reservoir 41, effectively providing three heating temperature settings and a desired moisture content in the hot food storage unit above the evaporator.

Referring to Fig. 8 of the drawings, there is shown a perspective view of a second embodiment of a front vent, indicated generally by the reference numeral 81, where like parts have been given the same reference numerals as before. The vent 81 is divided into a plurality of sections 82, 83, 84 having obround apertures therein and a pair of sections 85, 87 in which there are no apertures. In this way, air coming from the air discharge vents 23 is concentrated through the regions 82, 83 and 84 to direct the flow of air across the hot food in a more efficient manner. This directs the hot air to the areas where it is needed and reduces the incidences of hot spots developing in the food. The apertures are preferably 5mm wide and 48mm long and are spaced apart from each other by approximately 3mm.

It is envisaged that an alternative embodiment of front vent similar to the embodiment shown in Figure 8 could be provided with smaller apertures in the sections 85, 87 between the sections 82, 83 and sections 83, 84 respectively. The smaller apertures would also be spaced apart from each other by 3mm and would be 5mm in width however the smaller apertures would ideally be approximately 10mm in length. In this way, there would be a continuous row of apertures across the front vent with the apertures in sections 82, 83 and 84 the same as those shown in Figure 8 with smaller apertures in the sections 85 and 87 joining the rows of larger apertures in sections 82, 83 and 84.

Referring to Fig. 9 of the drawings, there is shown a second embodiment of air charging inlet, indicated generally by the reference numeral 91, where like parts have been given the same reference numerals as before. The air charging inlet 91 has an upstanding wall 93 below the obround apertures of the air charging inlet 27. This prevents ingress of foodstuffs into the heating compartment.

-11 -Referring to Fig. 10 of the drawings, there is shown a perspective view of a third embodiment of air charging inlet, indicated generally by the reference numeral 101, where like parts have been given the same reference numerals as before. The air charging inlet 101 has been divided into a number of sections 102, 103, 104 having air charging inlet apertures and a pair of sections 105, 106 in which the air charging inlet is blocked off by a solid sheet. In this way, air is more evenly distributed across the food as it comes in and the air being drawn by the tangential fans will be drawn in through the regions 102, 103, 104 thereby ensuring that the air is more evenly distributed across the food as it passes over the food in the food storage compartment en route to the air charging inlet.

In the embodiments shown in Figs. 8 and 10, it will be understood that instead of having solid regions 85, 87, 105, 106 such as those shown, it will be possible to have regions with less apertures, or smaller size of aperture to ensure less air flow in a particular area and it may indeed be preferred to simply reduce the amount of air flow in a particular area rather than blocking off the vent altogether. Furthermore, various different shapes and sizes of apertures other than obround apertures are envisaged.

In this specification the terms "comprise, comprises, comprised and comprising" and the terms "include, includes, included and including" are all deemed totally interchangeable and should be afforded the widest possible interpretation.

The invention is in no way limited to the embodiment hereinbefore described but may be varied in both construction and detail within the scope of the claims.

Claims

Claims: 1) A hot food storage unit of the type comprising: s a cabinet having a food storage compartment, a heating compartment, a transparent display shield covering the food in the food storage compartment and an opening in the display shield adjacent the rear of the cabinet to allow access to the food in the food storage compartment, in which:-the food storage compartment comprises a compartment floor for reception of food in containers; the heating compartment is located substantially below the food �5 storage compartment and comprises a plurality of primary heating units, a secondary heating unit, an air circulation duct and a plurality of fan units; the air circulation duct further comprising an air charging inlet located adjacent the rear of the cabinet in fluid communication with both the air circulation duct and the food storage compartment, and an air discharge outlet located adjacent the front of the cabinet in fluid communication with both the air circulation duct and the food storage compartment; the fan units each comprising a tangential fan, mounted in the air circulation duct adjacent the air charging inlet at the rear of the cabinet, and spaced apart laterally from each other in the cabinet, one of the tangential fans being mounted adjacent one side of the cabinet and the other tangential fan being mounted remote from the first tangential fan adjacent the other side of the cabinet, the tangential fans being operable to circulate air in the cabinet by drawing air into the air circulation duct of the heating compartment from the food storage compartment through the air charging inlet, driving the air along the air circulation duct and forcing the air out of the heating compartment to the food storage compartment through the air discharge outlet before drawing the air back in through the air charging inlet; the primary heating units each comprising a heating coil mounted in the air passageway located adjacent to the tangential fan and on the side of the tangential fan remote from the air inlet, the heating coil extending forwardly from the rear of the cabinet towards the front of the cabinet, one of the primary heating units being mounted adjacent one side of the cabinet and the other primary heating unit being mounted remote from the first primary heating unit adjacent the other side of the cabinet; the secondary heating unit comprising an evaporator, the evaporator comprising a liquid reservoir mounted above a secondary heating coil, the secondary heating coil extending forwardly from the rear of the cabinet towards the front of the cabinet and in which there is provided a liquid charging inlet in communication with the liquid reservoir of the evaporator and accessible from the rear of the cabinet so that liquid can be poured into the liquid reservoir from the rear of the cabinet; and the secondary heating unit is mounted in the air circulation duct intermediate the pair of adjacent heating coils of the primary heating units, thereby dividing the food storage compartment into a plurality of zones of varying moisture levels, a moist zone located centrally in the cabinet above the evaporator sandwiched between a pair of dry zones either side of the moist zone and located to the sides of the cabinet.
2) A hot food storage unit as claimed in claim I in which the liquid reservoir has a casing and in which the casing and one of the side walls of the cabinet form an isolated heated air channel in the air circulation duct and the casing and the other side wall of the cabinet form another isolated heated air channel in the air circulation duct.
3) A hot food storage unit as claimed in claim 1 or 2 in which the air charging inlet is provided with a plurality of apertures across the width of the cabinet, and in which one of the number and the size of the apertures is varied across the width of the cabinet.
4) A hot food storage unit as claimed in claim 3 in which there is a greater density of apertures in areas of the air charging inlet remote from the tangential fans than in areas adjacent to the tangential fans.
5) A hot food storage unit as claimed in any preceding claim in which the air discharge outlet is provided with a plurality of apertures across the width of the cabinet, and in which one of the number and the size of the apertures is varied across the width of the cabinet.
6) A hot food storage unit as claimed in any preceding claim in which the secondary heating unit comprises a pair of independently operable secondary heating coils, mounted in the casing constructed from a conductive material beneath the liquid reservoir.
7) A hot food storage unit as claimed in claim 6 in which one of the independently operable coils of the secondary heating unit has a power rating of the order of one half the power rating of the other independently operable coil in the secondary heating unit.
8) A hot food storage unit as claimed in any preceding claim in which the air charging inlet has a raised lip to prevent ingress of food into the heating compartment from the food storage compartment.
9) A hot food storage unit substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.