Source: http://www.google.com/patents/US5285051?dq=5787449
Timestamp: 2017-02-28 06:36:48
Document Index: 102126437

Matched Legal Cases: ['art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12']

Patent US5285051 - Rethermalization system including food service dish - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA rethermalization system for rethermalizing food includes (a) a food service tray having a hot dish through-opening and the through-opening having a through-opening top edge, (b) a rethermalization cart including a cart frame, a plurality of heating pads supported within the cart frame, and a plurality...http://www.google.com/patents/US5285051?utm_source=gb-gplus-sharePatent US5285051 - Rethermalization system including food service dishAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS5285051 APublication typeGrantApplication numberUS 07/794,630Publication dateFeb 8, 1994Filing dateNov 18, 1991Priority dateAug 15, 1989Fee statusLapsedPublication number07794630, 794630, US 5285051 A, US 5285051A, US-A-5285051, US5285051 A, US5285051AInventorsGary DeGrow, Julia T. Wimpee, Kevin B. Cundiff, Royce A. Payton, Roger W. Pepper, Leonard L. Mitchum, Jr., Robert A. McCoyOriginal AssigneeAladdin Synergetics, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (43), Non-Patent Citations (11), Referenced by (51), Classifications (24), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetRethermalization system including food service dish
US 5285051 AAbstract
1. A rethermalization system comprising:(a) a food service tray including a hot dish through-opening, said through-opening having a through-opening top edge and an inner surface; (b) a rethermalization cart including a cart frame, a plurality of heating pads supported within said cart frame, and a plurality of vertically spaced tray supports attached to said cart frame which supports said food service tray at a plurality of alternative vertically spaced shelf locations, and in a tray support position wherein said hot dish through-opening is disposed above one of said heating pads; and (c) a food service dish positionable in said hot dish through-opening of said food service tray, said food service dish including a bottom surface which allows heat transfer to occur from said heating pad to food in said food service dish with said tray in the tray support position; characterized in that: said food service dish includes an upwardly outwardly flaring side extending from said bottom surface, a generally vertical wall extending upwardly from said flaring side, and an upper lip projecting generally horizontal from said generally vertical wall; said food service dish is positionable in a heating position when said tray is in the support position, the heating position including said bottom surface thereof being supported by said heating pad such that said upper lip of said food service dish is slightly raised and out of contact from said through-opening top edge in order to reduce heat transfer between said food service dish and said food service tray; and said food service dish is positionable in a serving position when said tray is supported on a planar surface, the serving position including said food service dish being positioned relative to said through-opening such that said generally vertical wall is closely positioned horizontally adjacent to the inner surface of said through-opening with no intermediate member disposed therebetween in order to block excessive horizontal movement of said food service dish within said through-opening while the rethermalized food in said food service dish is being consumed. 2. The rethermalization system as recited in claim 1 wherein said food service dish is made as an integral one piece of ceramic material.
3. The rethermalization system as recited in claim 1 wherein said bottom surface and said upwardly outwardly flaring side of said food service dish are of a constant thickness.
4. The rethermalization system as recited in claim 1 wherein said upwardly outwardly flaring side has an outer surface which is frusto-conical.
5. The rethermalization system as recited in claim 1 wherein when in the serving position, said food service tray and said food service dish are both supported on the planar surface.
6. The rethermalization system as recited in claim 1 wherein said upper lip is continuous about the periphery of said food service dish.
7. The rethermalization system as recited in claim 1 wherein said food service dish is circular.
8. The rethermalization system as recited in claim 1 wherein said food service dish defines a first food service dish, said through-opening defines a first through-opening, said through-opening top edge defines a first through-opening top edge, said food service tray includes a second through-opening having a second through-opening top edge and a second inner surface, and further comprising a second food service dish positionable in said second through-opening.
9. The rethermalization system as recited in claim 8 wherein said second food service dish includes an upwardly outwardly flaring side extending from said bottom surface, a generally vertical wall extending upwardly from said flaring side, and an upper lip projecting generally horizontal from said generally vertical wall;said second food service dish is positionable in a heating position when said tray is in the support position, the heating position including said bottom surface of said second food service dish being supported by one said heating pad such that said upper lip of said second food service dish is slightly raised and out of contact from said second through-opening top edge in order to reduce heat transfer between said second food service dish and said food service tray; and said second food service dish is positionable in a serving position when said tray is supported on a planar surface, the serving position including said second food service dish being positioned relative to said second through-opening such that said generally vertical wall of said second food service dish is closely positioned horizontally adjacent to the inner surface of said second through-opening in order to block excessive horizontal movement of said second food service dish within said through-opening while the rethermalized food in said second food service dish is being consumed. 10. The rethermalization system as recited in claim 1 wherein said food service dish is constructed of a high heat resistant injection molded plastic.
11. The rethermalization system as recited in claim 1 wherein said food service dish is constructed of a highly conductive ceramic material.
12. The rethermalization system as recited in claim 11 wherein said ceramic material includes an alumina additive to increase its convectiveness.
13. The rethermalization system as recited in claim 1 wherein said bottom surface of said food service dish is flat in order to ensure proper heat conduction from said heating pad to food in said food service dish when said food service dish is in the heating position.
14. The rethermalization system as recited in claim 1 wherein said food service dish is generally flat with little concavity.
15. A rethermalization system comprising:(a) a food service tray including a hot dish through-opening, said through-opening having a through-opening top edge and an inner surface; (b) a rethermalization cart including a cart frame, a plurality of heating pads supported within said cart frame, and a plurality of vertically spaced tray supports attached to said cart frame which supports said food service tray at a plurality of alternative vertically spaced shelf locations, and in a tray support position wherein said hot dish through-opening is disposed above one of said heating pads; and (c) a food service dish positionable in said hot dish through-opening of said food service tray, said food service dish including a bottom surface which allows heat transfer to occur from said heating pad to food in said food service dish with said tray in the tray support position; characterized in that: said food service dish includes an upwardly outwardly flaring side extending from said bottom surface, a generally vertical wall extending upwardly from said flaring side, and an upper lip projecting generally horizontal from said generally vertical wall; said food service dish is positionable in a heating position when said tray is in the support position, the heating position including said bottom surface thereof being supported by said heating pad such that said upper lip of said food service dish is slightly raised and out of contact with said through-opening top edge in order to reduce heat transfer between said food service dish and said food service tray; said food service dish is positionable in a serving position when said tray is supported on a planar surface, the serving position including said food service dish being positioned relative to said through-opening such that said generally vertical wall is closely positioned horizontally adjacent to said inner surface of said through-opening in order to block excessive horizontal movement of said food service dish within said through-opening while the rethermalized food in said food service dish is being consumed, and said food service dish is positionable in a carrying position when said tray is being carried generally by edges thereof with said food service dish being supported by said upper lip being supported directly on and by said through-opening top edge. 16. A rethermalization system comprising:a rethermalization cart including a cart frame; at least one tray support and at least one heating pad, said tray support and said pad supported by said cart frame; at least one food service tray including at least one opening disposed therethrough, said opening having an inner surface disposed at a predetermined first level, said tray removably disposable within said cart and supported by said tray support with said opening disposed above said heating pad; at least one food service dish having a bottom surface and an outer wall, said outer wall defined by a first surface flared outwardly from said bottom surface and extending upwardly to a second level, a substantially vertical second surface extending upwardly from approximately the second level, said second surface disposed outwardly of said first surface, and a lip disposed above said second surface and extending outwardly, said dish removably disposable within said opening, wherein, when said dish is disposed within said opening said second surface is disposed closely adjacent said inner surface of said opening in the horizontal direction with the second level below the first level to prevent excessive movement in the horizontal direction, and when said dish is disposed within said opening while said tray is disposed within said cart said dish is supported by said heating pad with said lip disposed above and out of contact with said tray. 17. The system recited in claim 16, said dish outer wall including a stepped portion extending upwardly from approximately the second level, said stepped portion including said substantially vertical second surface.
18. The system recited in claim 17, said tray including an upwardly extending peripheral rim disposed about the periphery of said opening, said rim including said inner surface of said opening, wherein,when said dish is disposed in said opening, at least a portion of said stepped portion is disposed below at least a portion of said rim and said lip is disposed over said rim. 19. The system recited in claim 16, said tray including an upwardly extending peripheral rim disposed about the periphery of said opening, said rim including said inner surface of said opening, wherein,when said dish is disposed in said opening, at least a portion of said second surface is disposed below at least a portion of said rim and said lip is disposed over said rim. 20. The system recited in claim 16, said at least one heating pad comprising a plurality of heating pads, said at least one opening comprising a plurality of openings, each opening disposed above one said heating pad, said at least one dish comprising a plurality of dishes, one said dish disposable through each said opening and supported by one said heating pad.
21. The system recited in claim 20, said at least one tray support comprising a plurality of tray supports, each said tray support supported by said cart frame at a different vertical location, said at least one tray comprising a plurality of trays.
22. The system recited in claim 16, said at least one tray support comprising a plurality of tray supports, each said tray support supported by said cart frame at a different vertical location, said at least one tray comprising a plurality of trays.
23. The system recited in claim 14, said opening being substantially circular and having a first diameter, said second surface being substantially circular so as to give said dish a substantially constant diameter at said second surface, the constant diameter being less than the first diameter.
This application is a continuation of application Ser. No. 07/471,483, filed Jan. 29, 1990 which is a division of application Ser. No. 07/394,204 filed Aug. 15, 1989 now abandoned.
A significant drawback of systems which keep food warm for a short period of time before service is that the time period during which the food can be kept safe and warm is relatively limited, and the quality of the food deteriorates over time.
A rethermalization system is another prior art type of food service system. In a rethermalization system, food is cooked or prepared and then chilled in bulk to 40° F. or less. Eventually the food is divided into individual portions and stored in a chilled state until it is reheated. The United States Food and Drug Administration (FDA) guidelines specify that the chilled and stored temperature must be 40° F. or less. A short time before the food is to be served, the food which is to be served hot is brought to a safe serving temperature, i.e. it is rethermalized. FDA guidelines specify that a safe serving temperature is 165° F. or greater. The present invention is directed to certain improvements in structural and functional aspects of a rethermalization system which uses conductive heating.
Food service rethermalization systems which incorporate heating elements into the service tray have disadvantages similar to dish heating element systems. That is, the cost of the trays is relatively high and the trays are subject to breakage because of frequent handling during food service and cleaning. Exposed contacts are also required to provide electrical connection to the heating elements embedded in the trays. Another disadvantage of tray heating element systems is that the trays become warped after a period of time due to the frequent heating and cooling cycles to which the trays are subjected and their relatively large planar configuration. Once the trays become warped, good surface contact between the heating element portion of the tray and the dishes to be heated is lost. As a consequence, accurate, and possibly adequate, heat is not applied to the food during rethermalization. Examples of food service rethermalization systems which utilize trays incorporating heating elements are found in U.S. Pat. Nos. 4,068,115 to Mack et al.; 4,167,983 to Seider et al. and 4,235,282 to deFilippis et al.
Food service rethermalization systems which incorporate the heating elements into shelves supported in the service cart alleviate the problem of the high cost of the more replaceable portions of the system, i.e. expensive dishes and trays. Furthermore, since the heating elements are formed as a portion of the cart, i.e. a shelf within the cart, the connection of the electrical heating elements to a power source is incorporated within enclosed portions of the shelf and cart, alleviating the problem of exposed contacts. However, rethermalization carts with shelf located heating elements do have certain limitations or disadvantages. Such systems generally incorporate a plurality of heating elements in a fixed manner into a single shelf. Thus, when one of the heating elements on a shelf becomes inoperative, the entire shelf must be replaced, rather than replacing the single inoperative heating element. Examples of food service rethermalization systems wherein the heating elements are incorporated into shelves within the service cart are found in U.S. Pat. Nos. 4,346,756 to Dodd et al.; 4,323,110 to Rubbright et al. and 4,285,391 to Bourner.
Electrical conductive heaters in prior art rethermalization systems and rethermalization methods using such heaters have exhibited certain limitations or drawbacks in the manner in which the food is rethermalized. Most typically, a rethermalization system utilizes a resistance heater, which operates intermittently at a single power level during rethermalization, i.e. during the time when the food is initially brought from the chilled state to a serving temperature. The resistance heater is controlled by an on-off thermostat which operates between upper and lower temperature of limits. Typically, the resistance heater applies heat over a predetermined time period. While such a heating method has worked satisfactory, it is subject to certain limitations. For example, the system must be designed to work within a practical time period. While it would be desirable from a labor/cost standpoint to rethermalize chilled food as quickly as possible, it is difficult to achieve high quality food when rethermalization occurs too quickly. For example, certain portions of food may become scorched while others remain cold, or the food may become dehydrated or discolored when rethermalization occurs too rapidly.
One commercial rethermalization system accomplishes rethermalization of food in approximately one quarter of an hour. However, the range or variety of food which can be rethermalized is limited and special plating techniques are required for many of the lighter or more fragile foods. The term "plating techniques" refers to the special way or manner in which certain foods, which are to be rethermalized, are placed on dishware to assure that the foods retain their quality after rethermalization. Plating techniques are most frequently used with light and fragile foods. Examples of plating techniques include supporting food on a dish within a dish or on toast, adding gravy or water to the food, or spraying the dishes with a nonstick coating. Thus, while the time during which rethermalization takes place is less, any operating expense savings very likely lost by the added expense is required in the special plating techniques.
The system disclosed in Bourner '391 rethermalizes chilled food in approximately a one-half hour time period. Such a rethermalization time period has proven to be a satisfactory compromise. That is, a relatively wide variety of food can be rethermalized without the requirement of using special plating techniques. Furthermore, the one-half hour time period has not proven to be too restrictive on service personnel, allowing sufficient time for preparation and service of three meals per day in an institutional environment.
Nevertheless, even the system disclosed in Bourner '391 has certain limitations. For example, an unrestricted range of foods cannot be rethermalized without special plating or quality degradation. It is difficult to rethermalize small portions of low density, fragile foods, while retaining high quality of the foods and at the same time rethermalize large portions of high density, difficult to heat foods within the same time period. It is believed that one of the causes of this limitation is that the thermostat which controls the heater must operate at a relatively high temperature range in order to sufficiently heat the more difficult to rethermalize food, and that at such higher temperature ranges, the easier to heat foods become overcooked.
The system in Dodd et al. '756 uses a separate low power holding circuit for keeping food warm after it has been rethermalized. A higher power primary heating circuit is thermostatically controlled and used to rethermalize the food over a predetermined time period. Thus, while this system uses separate heaters having different power ratings, only the higher power heater is used for rethermalization, while the lower power heater is used primarily to keep the already rethermalized food warm. A switch is used to select between the two heating options.
The system in Mack et al. '115 uses PTC power heaters as the preferred type of heater embedded in the dish. The use of a resistance heater controlled by a thermostat is mentioned as an alternative to the PTC heater. The PTC heaters operate basically as multi-modal resistance heaters so that below their critical temperature they have a low electrical resistance, while above it the resistance is very high. Near the critical temperature, the resistance varies between the extremes. Therefore, depending upon temperature a PTC heater will deliver different wattages. During the development of the present system, it was found that PTC heaters had both structural and functional disadvantages. The heaters initially draw very high current, requiring more expensive high power capability electrical service. Also, if the initial input temperature of the food varied from preset standards, the heaters would not adequately heat the food to proper serving temperature.
The configuration of the dish in the prior art has typically been a flared outerwall design with a lip at the uppermost portion of the dish. The flared outerwall requires less precision with respect to the width of the opening in the tray. However, if the outerwall is flared too much, there will be too much "slop" due to the loose fit between the dish and the tray. This can lead to a shifting of the dish and concomitantly a shifting of the contents of the dish. This is undesirable.
Another consideration in the configuration of the dish is the desirability of allowing dishes to be stacked and/or nested within one another. With dishes having a flared wall, it is preferably to provide a lip at the top of the dish to provide a contact point and prevent movement between stacked dishes. However, if it is desired to make the dish more shallow, the use of a lip at the top of the dish may not be sufficient to achieve these objectives.
Another aspect of the present invention is directed to a system for selectively activating individual heaters in a food service cart. An individual switch mechanism is connected to each of the heaters for turning power on and off separately to each one of the heaters. A switch activator mechanism activates the switch mechanism, and is associated with covers for hot food to be carried on the service trays whereby one of the switch mechanism turns power on to a respective one of the heaters when one of the covers is carried by a tray and supported in the cart above the last-mentioned switch mechanism. In one embodiment, the switch mechanism includes a pivotable housing, a magnet supported at one end of the housing and a mercury switch activated and carried by the pivotable housing. A preferred form of switch activator mechanism is a ring of magnetic material supported in the base of the food cover.
Another aspect of the present invention is directed to a dish for use in a rethermalization device wherein the dish has a unique outerwall configuration to allow shallow dishes to be stacked and to prevent the "slop" or loose fit associated with prior art dishes having flared outerwalls.
FIG. 21 is a diagrammatic view of the resistance pattern of another heater element;
Referring to the drawings, wherein like numerals indicate like elements, there is illustrated a food service system indicated generally as 10. Food service system 10 includes a mobile food service cart 12' which functions as a rethermalization and service cart, and a refrigeration cabinet 14.
Cart 12 is formed generally of sheet metal and includes a support base 16. A first pair of wheels 18 depend from one of the sides of base 16 and a second pair of steerable and lockable wheels 20 depend from its other side. A first side wall 22 extends upwardly from a first side of base 16 and a second side wall 24 extends upwardly from a second side of base 16. A top wall 26 is connected to and extends between the upper ends of first and second side walls 22 and 24. Tubular members 25 (one of which is shown along the front edge of cart 12 in FIG. 1) are attached to the front and back edges of each side wall 22 and 24; and generally U-shaped tubular members 27 are attached to and connected between top wall 26 and side walls 22 and 24, and base 16 and side walls 22 and 24, along the front and back edges of cart 12. Tubular members 25, 27 provide additional rigidity to cart 12. A handle 28 is attached to the exterior of side wall 24, and is used to move and steer cart 12. The front and back of cart 12 are open to allow free access for the insertion and removal of food service trays 30. Male electrical connector contacts 32, which connect cart 12 to an electrical power source, extend from base 16 immediately below side wall 22.
As seen in FIG. 3, a pair of support bars 38 are attached to the inside surfaces of side walls 22 and 24 at both the front and back of cart 12. At a given horizontal location, support bars 38 define a front and back shelf location to support a pair of trays 30.
Support bars 38 are preferably formed of a rigid plastic. As seen in FIG. 4, support bars 38 have a generally T-shaped cross-section with pins 40 formed integral with the top section of the T. Pins 40 extend through apertures in side walls 22 and 24 to thereby secure support bars 38 to side walls 22 and 24. An alignment and locking projection 39 extends from the top surface of support bars 38. Projection 39 mates with a slot 41 along the bottom edge of tray 30 to hold tray 30 in position.
Tray 30 has a generally rectangular configuration with an upstanding peripheral rim 42, which extends upward from a support surface 44. A divider 46 also extends upward from the support surface 44 and divides surface 44 into a food holding area and a utensil/napkin holding area. In the food holding area a round large entree opening 48, and a round small soup opening 50, are formed. A rim 49 extends upward from surface 44 and around the periphery of opening 48. A rim 51 extends upward from surface 44 and around opening 50. As seen in FIG. 4, an entree dish 52 fits within entree opening 48 and a soup bowl 54 fits within soup opening 50. Entree dish 52 and soup bowl 54 both have a generally round shape. As seen in FIG. 5, the diameter of dish 52 increases slightly from its smallest diameter along its bottom surface, and is correlated to the diameter of opening 48 such that the bottom surface of dish 52 extends down slightly below the lower surface of tray 30, and the side and upper rim of dish 52 are out of contact with rim 49 of tray 30. The diameter of soup bowl 54 is likewise correlated to the diameter of opening 50.
As shown in FIG. 5, the outerwall of dish 52 has a configuration as follows. From the base, there is a flared portion characterized by the outerwall being flared outwardly from the base to a first predetermined point. The dish also has a step portion characterized by the outerwall protruding sharply outward with respect to the center of the dish from the first predetermined point to a second predetermined point. The outward protrusion or step may be substantially parallel to the base of the dish. From the outermost point of the protrusion, the outerwall has a vertical portion which extends substantially vertically upwards (has a relatively constant diameter) to a third predetermined point whereat the outerwall may extend outwardly to form a lip at the uppermost portion of the dish. Preferably the protrusion occurs at a position that when the dish is inserted through opening 48 of tray 30, the protrusion is below the upper portion of rim 49 of tray 30. Also, the diameter of dish 52 at the outermost portion of the protrusion is less than the diameter of opening 48. The first, second and third predetermined points are all preferably between the base and the uppermost portion of the dish.
This novel configuration provides the advantages of minimizing "slop" between the tray and dish and provides for better stacking/nesting of similar dishes. This is especially true if it is desired to make the dish shallower since the protrusion of one dish nests against the rim of the next dish. With the prior art flared-type outerwall, there is less stability when stacking dishes.
As also shown in FIG. 5, the dish may preferably have a round shape as opposed to a rectangular shape of the prior art. This round shape provides more surface area, therefore it is not necessary to make the dish as deep. This allows for shallower dishes to be used.
As seen in FIG. 3, a pair of large entree heater assemblies or modules 64 and a pair of small soup heater assemblies or modules 66 are located at each horizontal shelf location. FIGS. 9, 10, 11 and 12 illustrate the support structure for supporting heater modules 64 and 66 at the horizontal shelf locations. As seen therein, a generally T-shaped bar 68 extends between opposite side walls 22 and 24. T-bar 68 is preferably formed of a high strength aluminum material and includes a central rib 70, a cross member 72 which extends perpendicularly from opposite sides of rib 70, and a pair of wall members 74. Wall members 74 extend perpendicularly away from opposite distal ends of cross member 72 so that a hollow open-ended rectangular area is defined between cross member 72 and wall members 74. A base cover 76 fits within the hollow area and covers the open end between walls 74. Wiring, shown diagrammatically as 73, extends through the hollow area to connect the heater modules to a main power source through contacts 32. A plurality of notches 80 are formed in the interior of wall member 74, and projections or clips 82 extend from an upper surface of cover 76 and fit within notches 80 to secure base cover 76 in place.
Bar 68, base cover 76 and end pieces 84 are secured to walls 22 and 24, preferably by screws, one of which 81 is shown in dash-line in FIG. 9, extending through the walls and into end pieces 84. Four support pins 90 extend from each longitudinal edge of bars 68. Each pin 90 is attached to bar 68 in a conventional manner, preferably by screw threads. Pins 90 have a large diameter base portion 92 and a small diameter distal portion 94. A friction member, such as an O-ring 96, is secured to the distal end of base portion 92. Pins 90 function to support heater modules 64 and 66 in a cantilever manner from bar 68. As seen in FIG. 7, a cylindrical bore 98 is formed through the housing of heater module 64 adjacent each of its sides. Similar bores are formed in heater module 66. Pairs of pins 90 fit within bores 98 to support the heater modules. In this manner, heater modules 64 and 66 are supported at a plurality of vertically spaced shelf locations. The pin 90 and bore 98 connection and support technique allows each individual heater module, which is sized to heat a single dish or bowl, to be individually removed for service or replacement.
Heater plate 102 is preferably formed of a nickel plated aluminum plate having a thickness of approximately of 1/8". Plate 102 is generally round and has a circular perimeter generally mating with the configuration of round opening 124. A plurality of support legs 128 extend downward at a plurality of locations about the perimeter of heater plate 102. A resistive heating element 108, such as shown in FIG. 20, secured to the bottom of heater plate 102.
In the deactivated state of switch 116, the end of housing 130 which carries magnet 132 is pivoted downward and the opposite end carrying mercury switch 134 is pivoted upward. In this position mercury switch 134 is in its open state and power is not supplied to heating element 108. Switch 116 is activated by placing an insulated cover 56 over a dish of food to be rethermalized. As seen in FIG. 8 and 16, an annular ring 140 of a magnetic metallic material is held within the perimeter of cover 56 adjacent its base. As seen in FIG. 8, with tray 30 and cover 56 in position, magnet 132 is drawn upward toward metallic ring 140 and mercury switch 134 pivots downward to be placed in its closed state. Activation of an appropriate heater module is thus readily assured, since whenever an insulated cover is placed over food to be heated, the heater module is automatically activated. A cylindrical projection 142 is formed integral with the upper surface of housing 100 to receive magnet 132 and allow sufficient upward pivoting to activate mercury switch 134. A pair of electrical connector pins 144 are supported by a pair of spaced flanges 148 formed on plate 140 in a hermetically sealed manner. Pins 144 connect to a main power supply bypassing through holes 150 in the side T-bar 68 and connecting to electrical wiring 74 supported within the hollow interior of T-bar 68.
As seen in the graph, both systems initially supply heat to the system at the same rate. After the upper temperature of the thermostatic temperature range is reached, the prior art system completely shuts off its single power heater, while the present system continues to apply heat through a low power heater. Thus, as seen in the graph, the temperature sensed by the thermostat decreases more rapidly in the prior art system than the temperature sensed in the present system. As a result, over a typical rethermalization time period, the prior art system must cycle its heater on more frequently than the high power heater of the present system is cycled on. The chances of scorching of food being rethermalized occurs during the temperature peaks, so that there are more opportunities to scorch the food in the prior art system. This scorching danger is actually greater in typical prior art systems which operate at higher temperature ranges than illustrated in the theoretical graph shown in FIG. 25. For example, as will be discussed hereinafter, the method of the present invention operates the heaters within a thermostatic temperature range between 220° F. and 235° F.±5° F., whereas a typical prior art heater operating over the same predetermined time period would operate between 245° F. and 270° F. Prior art systems, which rethermalize in even shorter time periods, operate at even higher thermostatic ranges, e.g. 350° F. to 400° F.
As seen in Chart A, the food qualities which would determine whether a particular food is difficult or easy to heat include food density, portion size, configuration, moisture content, specific heat, and fragility. The variance of the supply voltage also effects the ability of the heater to heat the food.
Food density refers to mass per unit volume of the food, with the higher density food being more difficult to heat than the lower density foods. Larger portions of food, for example six ounces or more, are more difficult to heat than smaller portions of food, for example 1-1/2 to 3 ounces. The configuration of the food, in particular, the amount of surface area of the food which contacts the heating plate determines the ease with which a food can be heated. Flat food with relatively large surface area in contact with the heating plate is much easier to heat than unflat food which has very low surface contact with the heating plate. Moisture content also affects the ease with which the food can be heated, with the higher moisture content food, e.g. 70-75 percent liquid being easier to heat due to steaming than the foods with less moisture content, e.g. 38-75 percent liquid content. Specific heat also is a contributing factor to whether the food is difficult or easy to heat with foods of high specific heat, e.g. 0.85 to 0.95, being generally more difficult to heat than foods with low specific heat, e.g. 0.65 to 0.80. Fragility of food refers to whether a particular food can sustain its integrity and quality, e.g. not dry out or lose its color or texture, when it undergoes heating. Foods such as meatloaf, casseroles, lasagna and salisbury steaks are relatively sturdy and thus can undergo high energy heating, while such foods as poached eggs, omelets, rice, baked fish, pancakes and rare steaks are fragile and cannot undergo high intensity heating.
Foods with high energy heat requirement for example, a 4 to 6 ounce salisbury steak with 4 ounces of mashed potatoes and 4 ounces of broccoli spears were thereafter tested in the following manner: The selected low power heater was run continuously and additional power was supplied by a secondary heater at progressively higher power until the high energy heat requirement food was adequately rethermalized from below 40° F. to above 165° F. The intermittent application of the additional power was controlled between predetermined thermostatic settings. Once a high power or additional power setting was determined, the combinations of low power and high power settings was tested on low heat energy requirement food to determine if the food could be adequately heated or if its quality was destroyed. Adjustments were made up and down the power scale on both the low power heater and high power heater with the power to the high power heater being decreased when the power to the low power heater was increased. Through this process, it was eventually determined that optimum power settings for the high and low power heaters was a low power setting slightly lower than the initial setting of the low power heater for low energy requirement foods and a slightly increased power setting for the high power heater over the initial power supplied to the high heat energy requirement foods.
This test procedure was used at progressively lower thermostat range settings. That is, initial testing occurred at a typical higher prior art thermostatic range, e.g. between 245° F. to 280° F. However, it was eventually determined that a thermostatic temperature range between 215° F. and 240° F., preferably between 220° F. and 235° F., and power supplied at 41 watts at the low power setting and 156 watts at the high power setting accomplished the objectives of satisfactory rethermalizing entree food or both high and low energy requirements, as well as rethermalizing mixtures of low and high energy requirement of food such as shown in Chart A. Suitable power ranges for the entree heater should be approximately 35 to 45 watts for low power and 150 to 160 watts for high power.
__________________________________________________________________________Chart AHeat           Size of       Moisture                              Specific          TestedRequirement   Food Density          Portion                 Configuration                        Content                              Heat Fragility                                          Voltage                                                Examples__________________________________________________________________________High    (High) Large (6 oz                 Unflat/low                        Low   High Sturdy Low   4-6 oz salisbury   meat loaf          or more)                 Surface Area                        (38-75%)                              (.85-.95)                                   meatloaf                                          108   steaks, 4 oz   lasagna          total plate                 broccoli                        ham   apples                                   casseroles   mashed potato,   potatoes          weight brussel spts                        bk. chkn.                              potatoes                                   lasagna      4 oz. broc sprs.   mac &amp; cheese          10-12 oz.                 bk. potato        sals. stk.   chicken thigh,   chicken          bone-in chkn.                 mac. &amp; chs.                    4 oz (bone-in),   oatmeal          lasagna                               3 oz brussel                                                sprouts, 4-5 oz                                                baked potato                                                7 oz sal. stk. +                                                6 oz mashed pot.                                                2 oz carrots                                                4-6 oz oatmeal                                                4-6 oz brothLow     (Low)  Small  Flat/Large                        High  Low  Fragile                                          High  pched egg, toast   rice   (1.5-3 oz.)                 Surface Area                        (75-95%)                              (.65-.80)                                   poached eggs                                          125   one chs. omlte   omelette          total plate                 sliced meats                        spinach                              ham  omelette     2 oz. peas or   pancakes          weight casseroles                        casseroles                              chicken                                   rice         corn or rice   bread, rolls          3-4 oz.                 steaks gravies                              sausage                                   rst. beef    2 pancakes   peas          mash. pot.                        beef  beef baked fish   (stacked)   corn                 broth      pancakes     (stacked)                                   stk (rare)   rollsMixed                                                8 oz. Lasagna                                                (tall) + 1.5 oz.                                                green peas                                                whole baked pot.                                                + 2 oz. sliced                                                roast beef                                                6 oz. meat loaf,                                                2 oz. rice                                                4 oz. rice, 6 oz                                                glazed chicken                                                (Oriental)                                                8 oz. mac &amp; ch.                                                2.5 oz. broc.                                                6 oz. stuffed                                                baked flounder +                                                2 oz. green__________________________________________________________________________                                                peas
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS2028649 *Sep 5, 1934Jan 21, 1936Conroy James PBroilerUS2210521 *Jul 29, 1939Aug 6, 1940Bemis Kenneth ECombined cooking, baking, and serving unitUS2222065 *Aug 16, 1937Nov 19, 1940Kalamazoo Stove & Furnace CompCombination combustion and electric stoveUS2330867 *Sep 9, 1940Oct 5, 1943Firm Entpr S Electr FribourgeoElectric heating plateUS2668222 *Mar 3, 1951Feb 2, 1954Gen Motors CorpDomestic applianceUS2906412 *May 24, 1956Sep 29, 1959Tanner Clarence MFood trayUS3140389 *Jul 13, 1962Jul 7, 1964Bette L WindesPlate warmerUS3270660 *Jul 23, 1964Sep 6, 1966Westinghouse Electric CorpCooking ovenUS3470944 *Sep 3, 1968Oct 7, 1969Samson Plastics IncPlatter coverUS3608770 *Jun 10, 1969Sep 28, 1971Continental Can CoApparatus and system for food preparationUS3725645 *Sep 25, 1970Apr 3, 1973Shevlin TCasserole for storing and cooking foodstuffsUS3750083 *Jun 22, 1970Jul 31, 1973Minnesota Mining & MfgMagnetic electric connectorUS3797563 *Nov 18, 1971Mar 19, 1974Carter Hoffmann CorpPortable food service equipmentUS3799143 *Nov 24, 1971Mar 26, 1974Aladdin Ind IncFood service systemUS3830148 *Oct 15, 1973Aug 20, 1974Minnesota Mining & MfgDevice and method for storing and cooking foodUS3875370 *Mar 7, 1974Apr 1, 1975Standex Int CorpHeat-retaining food service unitUS3908749 *Mar 7, 1974Sep 30, 1975Standex Int CorpFood service systemUS3982584 *Apr 23, 1975Sep 28, 1976Owens-Illinois, Inc.Gas temperature and flow control systemUS3987719 *Jul 23, 1973Oct 26, 1976Leonard KianCooking utensilUS4005745 *Sep 30, 1974Feb 1, 1977Anchor Hocking CorporationApparatus for storing, refrigerating and heating food itemsUS4059096 *May 19, 1976Nov 22, 1977Imperial Arts CorporationUnitized serving base with imperforate pelletUS4068115 *Jul 17, 1975Jan 10, 1978Sweetheart Plastics, Inc.Food serving trayUS4093041 *Apr 19, 1976Jun 6, 1978Sweetheart Plastics, Inc.Food serving systemUS4103736 *Aug 2, 1976Aug 1, 1978Anchor Hocking CorporationApparatus for heating a food item while retaining its moisture and nutritional componentsUS4116363 *Oct 25, 1977Sep 26, 1978General Electric CompanySecuring means for cooking vesselsUS4147924 *Aug 8, 1977Apr 3, 1979Dewitt Jr Charles MTortilla warmerUS4167983 *Apr 30, 1975Sep 18, 1979Gould Inc.Electrically powered service vehicleUS4235282 *Jan 3, 1978Nov 25, 1980Filippis Modeste DeHeating and refrigerating tray cabinet for distributing hot and cold dishesUS4246884 *Aug 17, 1979Jan 27, 1981Mcgraw-Edison CompanyPlate warmerUS4285391 *Aug 29, 1979Aug 25, 1981Aladdin Industries, IncorporatedElectrical system for food service devicesUS4323110 *Feb 21, 1979Apr 6, 1982Anchor Hocking CorporationFood preparation processUS4346756 *Aug 20, 1980Aug 31, 1982Uop Inc.Apparatus for selectively heating an individual food item in a refrigerated environmentUS4493978 *Jul 11, 1983Jan 15, 1985Starnes Roger AServing dish with heating meansUS4517446 *Apr 26, 1982May 14, 1985Safeway Products Inc.Heating shelfUS4780597 *Jun 17, 1987Oct 25, 1988Licentia Patent-Verwaltungs GmbhElectrical baking and roasting ovenUS4781243 *Dec 11, 1986Nov 1, 1988The Boeing CompanyThermo container wallUS4805526 *Dec 17, 1986Feb 21, 1989Teobaldo RivaBaking plateUSRE30623 *May 2, 1980May 26, 1981Uop Inc.Apparatus for selectively heating an individual food item in a refrigerated environmentUSRE30962 *Jul 20, 1979Jun 8, 1982Aladdin Industries, IncorporatedInsulated trays for food or the likeEP0024992A1 *Aug 27, 1980Mar 11, 1981Robot-CoupeSecurity device for a food processing apparatusFR1219352A * Title not availableFR2285836A1 * Title not availableGB2066594A * Title not available* Cited by examinerNon-Patent CitationsReference1 *Aladdin Advanced Meal Systems Brochure, 1987 (month unknown).2 *Aladdin Advanced Meal Systems Rethermalization Systems Brochure, Oct. 1988.3 *Aladdin Advanced Meal Systems Temp Rite II Excel Rethermalization Cart Brochure, Nov. 1989.4Aladdin Advanced Meal Systems Temp-Rite II Excel Rethermalization Cart Brochure, Nov. 1989.5 *Aladdin Advanced Meal Systems Walk In Rethermalization Refrigerator Brochure, Nov. 1989.6Aladdin Advanced Meal Systems Walk-In Rethermalization Refrigerator Brochure, Nov. 1989.7 *Aladdin Advanced Meal Systems, Temp Rite II Excel Brochure, Nov. 1989.8Aladdin Advanced Meal Systems, Temp-Rite II Excel Brochure, Nov. 1989.9 *Counselor, vol. 10, No. 1, 1988 (month unknown).10 *Therma Chill Food Productins Systems, Perfect Temp Quality Meals at Lower Operating Costs Brochure (date unknown).11Therma-Chill Food Productins Systems, Perfect-Temp Quality Meals at Lower Operating Costs Brochure (date unknown).* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5628241 *Aug 5, 1996May 13, 1997Societe Cooperative De Production BourgeoisInduction heating device for meal traysUS5655595 *Sep 5, 1996Aug 12, 1997Standex International CorporationConvection rethermalization systemUS5771959 *Sep 21, 1994Jun 30, 1998Standex International CorporationRethermalization systemUS5783803 *Dec 20, 1995Jul 21, 1998Robards, Jr.; Chester F.Food warming apparatusUS5797445 *Jun 6, 1995Aug 25, 1998Standex International CorporationRefrigerated rethermalization cartUS5852967 *Feb 3, 1997Dec 29, 1998Restaurant Technology, Inc.Food treatment systemUS5868195 *Nov 23, 1992Feb 9, 1999Standex International CorporationRethermalization systemUS5894788 *Oct 23, 1997Apr 20, 1999Societe Cooperative De Production BourgeoisTray for heating foodUS5896915 *Dec 12, 1997Apr 27, 1999Standex International CorporationRethermalization systemUS5910210 *May 15, 1998Jun 8, 1999Societe Cooperative De Production BourgeoisDevice for institutional distribution of mealsUS5921096 *Oct 9, 1997Jul 13, 1999Warren; John S.Modular temperature maintaining food receptacle systemUS5947012 *Mar 9, 1998Sep 7, 1999Restaurant Technology, Inc.Cooked food staging device and methodUS6021709 *Oct 28, 1998Feb 8, 2000Henny Penny CorporationApparatus, system, and methods for preparing food products using high velocity air flowUS6021710 *Jul 29, 1998Feb 8, 2000Societe Cooperative De Production BourgeoisTray for heating foodUS6034355 *Jun 8, 1998Mar 7, 2000A La Cart, Inc.Meal delivery systemUS6105818 *May 8, 1996Aug 22, 2000Burlodge LimitedFood dispensing cycle and meansUS6116154 *Aug 10, 1999Sep 12, 2000Prince Castle Inc.Food pan management system in food warming apparatusUS6120819 *Apr 16, 1999Sep 19, 2000Societe Cooperative De Production BourgeoisMethod for institutional distribution of mealsUS6259065Apr 28, 2000Jul 10, 2001Henny Penny CorporationMerchandisers with central heating and control mechanisms and methods for manufacturing and reconfiguring such merchandisersUS6279470 *Dec 4, 2000Aug 28, 2001Biontronics S.A.Portable and self-contained system for maintaining prepared meals in a cool state and reheating themUS6315039 *Nov 9, 1999Nov 13, 2001Standex International CorporationBedside rethermalization unitUS6358548Apr 13, 1999Mar 19, 2002Restaurant Technology, Inc.Cooked food staging device and methodUS6386098 *Apr 6, 2001May 14, 2002C. Cretors & Co.Pre-packaged food warmerUS6412403 *Feb 29, 2000Jul 2, 2002Prince Castle, Inc.Apparatus and method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS6607766Oct 1, 2001Aug 19, 2003Restaurant Technology, Inc.Cooked food staging device and methodUS6627855Jul 10, 2001Sep 30, 2003Henny Penny CorporationMerchandisers with central heating and control mechanisms and methods for manufacturing and reconfiguring such merchandisersUS6637322 *Feb 27, 2002Oct 28, 2003Prince Castle Inc.Apparatus for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS6707008 *Jun 1, 2001Mar 16, 2004Nestec S.A.Method and apparatus for controlling the drying of previously baked goodsUS6745675 *Nov 6, 2001Jun 8, 2004Societe Cooperative De Production BourgeoisDevice for preservation and rethermalization of meal traysUS6878391Dec 2, 2002Apr 12, 2005Prince Castle Inc.Method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS6884451Feb 22, 2002Apr 26, 2005Prince Castle Inc.Method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS7025121Aug 6, 2003Apr 11, 2006Aladdin Temp-Rite, LlcRefrigeration/rethermalization food delivery systemUS7950679Jun 25, 2007May 31, 2011Joseph ClaffyInsulated food tray wagonUS8299656 *Aug 12, 2009Oct 30, 2012Whirlpool CorporationFeature module connection systemUS9252570 *Jun 4, 2013Feb 2, 2016Whirlpool CorporationCountertop module utilities enabled via connectionUS20020094361 *Feb 22, 2002Jul 18, 2002Veltrop Loren J.Apparatus and method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS20020100756 *Feb 22, 2002Aug 1, 2002Veltrop Loren J.Apparatus and method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS20020102337 *Feb 22, 2002Aug 1, 2002Veltrop Loren J.Apparatus and method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS20030118706 *Dec 2, 2002Jun 26, 2003Prince Castle, Inc.Apparatus and method for maintaining cooked food in a ready-to-serve condition using a freestanding cover for food traysUS20030226657 *Apr 1, 2002Dec 11, 2003Wallace Thomas E.Food delivery system and method for storing and heating food to a serving temperatureUS20040011220 *Nov 6, 2001Jan 22, 2004Philippe RichardDevice for preservation and rethermalization of meal traysUS20040086606 *Sep 17, 2003May 6, 2004Nestec S.A.Baked cookies having dual textureUS20050028543 *Aug 6, 2003Feb 10, 2005Whitehead Lara LeeRefrigeration/rethermalization food delivery systemUS20080006593 *Jul 5, 2006Jan 10, 2008Northrop Grumman CorporationModular rack designUS20080083725 *Aug 29, 2006Apr 10, 2008Robert Edward SteaseSelf-Heating Group Meal AssemblyUS20080315624 *Jun 25, 2007Dec 25, 2008Joseph ClaffyInsulated food tray wagonUS20090302724 *Aug 12, 2009Dec 10, 2009Whirlpool CorporationPark place refrigerator module utilities enabled via connectionUS20130255662 *Mar 28, 2013Oct 3, 2013B/E Aerospace, Inc.Oven Having Slidable Drawer MechanismUS20130264439 *Jun 4, 2013Oct 10, 2013Whirlpool CorporationRefrigerator module utilities enabled via connectionUSRE39551May 8, 1996Apr 10, 2007Burlodge LimitedFood dispensing cycle and meansEP1085386A1 *Jun 28, 2000Mar 21, 2001KUHNKE GmbHElectrically controlled drive apparatus* Cited by examinerClassifications U.S. Classification219/386, 165/919International ClassificationB65D81/38, A23L3/365, G05D23/19, H05B3/68, H05B3/74, A47J39/00Cooperative ClassificationY10S165/919, H05B3/746, H05B2213/04, H05B3/68, B65D81/3825, A47B2031/002, A47J39/006, G05D23/1912, H05B2213/07, A23L3/365European ClassificationH05B3/74P, G05D23/19C4, A23L3/365, A47J39/00B, B65D81/38C, H05B3/68Legal EventsDateCodeEventDescriptionJan 14, 1997ASAssignmentOwner name: HARRIS TRUST AND SAVINGS BANK, ILLINOISFree format text: PATENT COLLATERAL AGREEMENT;ASSIGNOR:ALADDIN INDUSTRIES, INCORPORATED;REEL/FRAME:008442/0540Effective date: 19961023Sep 16, 1997REMIMaintenance fee reminder mailedFeb 8, 1998LAPSLapse for failure to pay maintenance feesApr 21, 1998FPExpired due to failure to pay maintenance feeEffective date: 19980211Oct 7, 1998ASAssignmentOwner name: ALADDIN INDUSTRIES, INC., TENNESSEEFree format text: SECURITY AGREEMENT RELEASE;ASSIGNOR:HARRIS TRUST AND SAVINGS BANK;REEL/FRAME:009500/0800Effective date: 19961023RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services