FORTMANN, Robert, C. (33000 North Forrest Drive, Grayslake, IL, 60030, US)
| CLAIMS
1. A system for heating a banquet cart comprising: a cart defining an interior compartment configured to receive a heated food product therein, the compartment being accessible by at least one door; a heating compartment configured to receive one or more slabs of plastic solid to solid phase change material therein, the heating compartment configured to allow thermal communication with the interior compartment, the heating compartment being accessible without manipulating the at least one door of the cart; and a heating system disposed external to the body and configured to receive two or more slabs of plastic solid to solid phase change material and impart heat thereto to preheat the two or more slabs of plastic solid to solid phase change material prior to placement within the heating compartment.
2. The system of claim 1 , wherein the heating system comprises a cabinet that includes an internal volume, two or more members configured to receive two or more slabs of plastic solid to solid phase change material, and a heat source disposed therein and configured to simultaneously apply heat to two or more slabs of plastic solid to solid phase change material disposed therein.
3. The system of claim 2, wherein the heat source comprises a heater and a fan operable to disburse heat generated by the heat source through the internal volume of the cabinet.
4. The system of claim 3, wherein the cabinet defines two or more conduits to direct heated air from the heat source to proximate each of the two or more slabs disposed therein.
5. The system of claim 2, wherein the heat source is disposed above the one or more racks.
6. The system of claim 2, wherein the heat source is disposed above the one or more racks.
7. The system of claim 1 , wherein the heating compartment includes a drawer that is configured to be selectively inserted and withdrawn from the cart.
8. The system of claim 7, wherein the drawer comprises a frame configured to receive and mechanically support the slab of plastic solid to solid phase change material therein.
9. The system of claim 8, wherein the frame is configured to receive two or more slabs of plastic solid to solid phase change material therein.
10. The system of claim 7, wherein the drawer comprises two or more drawers that are each configured to be independently selectively inserted and withdrawn from the cart.
11. A heating system for a banquet cart, comprising: one or more slabs of plastic solid to solid phase change material configured to be removeably deposited in thermal communication with an internal compartment of a banquet cart; a drawer configured to receive the one or more slabs to plastic solid to solid phase change material, wherein the drawer is removeably accessible without directly accessing the internal compartment of the banquet cart; and a heater disposed external to the banquet cart, the heater configured to receive the one or more slabs of plastic solid to solid phase change material and to apply heat thereto.
12. A method of providing heat to a banquet cart, comprising the steps of: depositing two or more slabs of plastic solid to solid phase change material proximate a heat source configured to simultaneously provide heat to the two or more slabs of the plastic solid to solid phase change material; heating the two or more slabs of plastic solid to solid phase change material until the two or more slabs transform to a transient second solid phase; and placing the two or more slabs of plastic solid to solid phase change material in the second solid phase within a heating compartment disposed in thermal communication with an internal volume of a banquet cart.
13. The method of claim 12, wherein the one or more slabs are placed within the heating compartment without opening a door to the internal volume of the banquet compartment, wherein the door is configured to allow a plurality plates or trays of food product to be inserted into or removed from the internal volume of the banquet cart.
14. A heating apparatus, comprising: a housing defining a plurality of outer walls defining an internal volume selectively isolatable by a door movably mounted upon the housing; a plurality of members disposed upon the outer walls and configured to receive and support two or more slabs of plastic solid to solid phase change material; and a heater and a fan disposed proximate thereto, the heater and fan configured to project a flow of heated convection air within the internal volume and proximate each of the two or more slabs of plastic solid to solid phase change material.
15. The heating apparatus of claim 14, further comprising a plurality of conduits defined in one or more of the plurality of outer walls to direct air from the fan and heater to flow proximate at least one outer surface of each of the two or more slabs of plastic solid to solid phase change material.
16. The heating apparatus of claim 14, further comprising an induction heater disposed upon the housing, the induction heater configured to receive one or more slabs of plastic solid to solid phase change material thereon and provide a rapidly changing magnetic field to the one or more slabs of plastic solid to solid phase change material. |
APPARATUS AND SYSTEM FOR HEATING TRANSPORTABLE
BANQUET CART
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority from United States Provisional Application No. 61/055,724, filed on May 23, 2008, the entirety of which is hereby incorporated by reference herein.
TECHNICAL FIELD
[0002] The present disclosure relates generally to a transportable banquet cart that stores plates or trays of food for later serving in a remote location. Banquet carts are employed in hotels, restaurants, and convention centers to keep plates of prepared food warm prior to serving at dinners, parties, or receptions. The banquet cart is normally filled with a plurality of plates or trays of cooked or warmed food in a kitchen and then transported to a location proximate to where the food will be consumed. In many facilities, electric power is not conveniently available in the location where the banquet cart is placed proximate to where the food will be consumed.
BRIEF SUMMARY
[0003] A first representative embodiment of the disclosure provides a system for heating a banquet cart. The system includes a cart defining an interior compartment configured to receive a heated food product therein, the compartment being accessible by at least one door. A heating compartment is configured to receive one or more slabs of plastic solid to solid phase change material therein, the heating compartment is additionally configured to allow thermal communication with the interior compartment, the heating compartment is accessible without manipulating the at least one door of the cart. A heating system is disposed external to the body and selectively receives the slab of plastic solid to solid phase change material and imparts heat thereto to preheat the one or more slabs of plastic solid to solid phase change material prior to placement within the body.
[0004] A second representative embodiment of the disclosure provides a heating system for a banquet cart. The heating system includes one or more
slabs of plastic solid to solid phase change material that are configured to be removeably deposited in thermal communication with an internal compartment of a banquet cart. A drawer is configured to receive the one or more slabs of plastic solid to solid phase change material, wherein the drawer is removeably accessible without directly accessing the internal compartment of the banquet cart. A heater is disposed external to the banquet cart and configured to receive the one or more slabs of plastic solid to solid phase change material and to apply heat thereto.
[0005] A third representative embodiment of the disclosure provides a method of providing heat to a banquet cart. The method includes the steps of depositing two or more slabs of plastic solid to solid phase change material proximate a heat source configured to simultaneously provide heat to two or more slabs of the plastic solid to solid phase change material. A step of heating the two or more slabs of plastic solid to solid phase change material until the one or more slabs transform to a transient second solid phase is provided. A step of placing the two or more slabs of plastic solid to solid phase change material in the second solid phase within a heating compartment disposed in thermal communication with an internal volume of a banquet cart is provided.
[0006] A fourth representative embodiment of the disclosure provides a heating apparatus. The heating apparatus includes a housing defining a plurality of outer walls defining an internal volume selectively isolatable by a door movably mounted upon the housing and a plurality of members disposed upon the outer walls and configured to receive and support two or more slabs of plastic solid to solid phase change material. A heater and a fan are disposed proximate thereto, the heater and fan configured to project a flow of heated convection air within the internal volume and proximate each of the two or more slabs of plastic solid to solid phase change material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of a system for heating a banquet cart.
[0008] FIG. 2 is the banquet cart of the system of FIG. 1 with a drawer partially removed.
[0009] FIG. 3 is a perspective view of the drawer of FIG. 1.
[0010] FIG. 4 is a perspective view of an alternate drawer for use with the system of FIG. 1.
[0011] FIG. 5 is a front view of the heating apparatus of the system of FIG. 1 with the doors removed.
[0012] FIG. 6 is a perspective view of an alternate heating apparatus useable with the system of FIG. 1 !
DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED EMBODIMENTS
[0013] Turning now to FIGs. 1-4, a system 300 for heating a banquet cart 310 is provided. The banquet cart 310 includes a housing 320 that is configured to receive a plurality of heated food items therein for temporary storage after being cooked, prepared, or processed in a kitchen of a commercial establishment and prior to serving to the customer. The housing 320 includes an internal volume 321 that is configured to receive a plurality of plates or pans 390 therein upon a plurality of racks 392. The housing 320 normally includes insulated external walls to substantially attenuate heat transfer therethrough to maintain the food disposed within the internal volume 321 at a sufficient elevated temperature as long as possible. The housing 320 further includes one or more doors 322 that are pivotably or otherwise movably received upon the housing 320 to selectively open the internal volume 321 to allow plates or pans 390 of food to be inserted or withdrawn from the internal volume 321 of the housing 320. The one or more doors 322 may be insulated to substantially attenuate conductive heat transfer therethrough and may include a gasket or similar member disposed on one or both of the door 322 or housing 320 to provide additional resistance to heat flowing from the internal volume 321 of the housing 320 when the one or more doors 322 are closed.
[0014] The banquet cart 310 additionally includes one or more drawers 330 that are normally disposed in a lower portion of the housing 320. The drawers 330 are operable between an inserted position (FIG. 1) within the housing 320 where the drawer 330 is in thermal communication with the internal volume 320 of the cart 310 and a withdrawn position (FIG. 2) where an internal volume of the
drawer 330 is accessible by the user with the one or more doors 322 in the closed position. In some embodiments, two or more drawers 330 may be provided upon the cart 310 and configured to be independently opened or closed. In other embodiments, a single drawer 330 is provided that is configured to receive two or more slabs 350 of plastic solid to solid phase change material (discussed below). As can be understood, it is beneficial to minimize the number of times that the doors 322 of the internal volume 321 are opened, because doing so allows a significant amount of stored heat and moisture to leave the internal volume 321 , and therefore accelerates the cool down and dryout of the food disposed therein without sufficient and rapid heat addition to the internal volume 321.
[0015] As best shown in FIG. 3, the one or more drawers 330 are each configured to receive one or more slabs 350 of plastic solid to solid plastic material, such that the one or more slabs 350 are each disposed in thermal communication with the internal volume 321 of the cart 310 when the drawers 330 are disposed in the closed position. The drawers 330 each include a frame 332 that is rigidly assembled and defines a cavity 333 sized and shaped to receive a slab 350 of plastic solid to solid phase change material. The cavity 333 is defined by the frame 332 with substantially the same geometrical shape as the slab 350. In some embodiments, the frame 332 is configured to receive a flat and relatively thin slab 350 of material to maximize the amount of surface area of the slab 350 that is exposed to the internal volume 321 of the cart 310 to provide a heat source thereto. In other embodiments shown in FIG. 4, the drawer 330 and frame 332 are configured to receive two or more slabs 350 of plastic solid to solid phase change material within the two cavities 333 defined therein. In some embodiments, two or more drawers 330 are provided that each receive one, two, or more slabs 350 of material. The frame 332 may include one or more recessed areas, or apertures 334 to provide space for the slab 350 to be manipulated by tongs or a hot pad held by the user to allow the slab 350 to be precisely installed within the frame 332 when in the second heated condition (discussed below). [0016] The slabs 350 of plastic solid to solid phase change material are normally preheated externally from the cart 310 and the drawer 330 until the
slabs 350 each receive sufficient heat to transfer the slabs 350 from a normal first solid state to a heated second solid state. One example of the plastic solid to solid phase change material that is suitable for use with the slabs 350 is sold by CookTek, Inc. of Chicago, IL. In some embodiments suitable slabs 350 may be made from plastic solid to solid phase change material that changes phase from the normal solid state to the transient heated second solid state at approximately 270 degrees Fahrenheit. In other embodiments, other types of plastic solid to solid phase change materials known in the art may be use to form the slabs 350. In still other embodiments, other materials that collect heat quickly and cool slowly may be used for the one or more slabs 350, such as aluminum or wax. [0017] In some embodiments shown in FIG. 2, one or more sensors 360 may be disposed at differing locations within the internal volume 321 of the cart that are connected to a display 362 to provide the user with an indication of the temperatures at different locations within the cart 310, and therefore an approximation of the temperature of the food disposed within the cart 310. The one or more sensors 360 may provide temperature readings proximate the drawer 330 (and therefore proximate the slab 350 of plastic solid to solid phase change material) at a first position proximate the lowest possible food position within the internal volume 321 , a mid position within the internal volume 321 , and an upper position within the internal volume 321. The temperature sensors 360 and the display 362 allow the user to monitor the operational performance of the slab 350 as well as the temperatures within the internal volume of the cart 320 to allow for action (such as replacing a discharged slab 350 of plastic solid to solid phase change material with a charged or heated slab 350, as necessary) to maintain the food temperatures at a desired level after an extended period of time. The one or more sensors 360 and display 362 may be powered from one or more batteries (rechargeable or otherwise) to provide power to operate the sensors 360 and display 362 when the cart 310 is not connected an AC power source.
[0018] In some embodiments, the cart 310 may additionally include one or more electric heaters 380 disposed therein. The heaters 380 are provided to preheat the internal volume 320 and the internal mass (i.e. shelving, internal
walis, etc.) of the cart 310 prior to and when the cart 310 is loaded with food such that the slab 350 of plastic solid to solid phase changer material is only tasked with maintaining the internal temperatures (and the internal mass) of the cart 310, as opposed with increasing the internal temperature (and internal mass) of the cart 310 to a temperature suitable for long term storage of the food disposed therein. The use of internal heaters 380 allows the slab 350 of plastic solid to solid phase change material to maintain the temperature of the food disposed therein at an acceptable temperature for an extended period of time. The electric heaters 380 may additionally be energized after the cart 310 is stocked with food for an extended period of time and the slab or slabs 350 have sufficiently cooled. The embodiments with internal electric heaters 380 include power cords (not shown but conventional) to receive electric current from a municipal source to power the heaters 380 as necessary.
[0019] As best shown in FIGs. 1 and 5, an external heating apparatus 400 is provided to receive two or more slabs 350 of plastic solid to solid phase change material and simultaneously provide heat to the two or more slabs 350 disposed therein. The heating apparatus 400 may be configured as a cabinet 410 that includes a housing that defines an internal volume 412 that may be enclosed with a door 414. The housing 410 may include one or more electric heaters 420 and a fan 422 to provide forced convection of heated air through the internal volume 412 of the cabinet 410. In some embodiments, the electric heaters 420 and fan 422 may be disposed above the two or more slabs 350 when received within the cabinet 410. In other embodiments, the electric heaters 420 and fan may be disposed below the two or more slabs 350 when received within the cabinet 410. In still other embodiments, the electric heaters 420 and fan 422 may be disposed between a first upper area configured to receive one or more slabs 350 and a second lower area configured to receive one or more slabs 350. [0020] In some embodiments, the cabinet 410 may include a plurality of conduits 424 disposed therein and fixed to one or more walls that define the housing 410, which direct heated air from the electric heaters 420 (as urged by the fan 422) to flow past each of the slabs 350 of plastic solid to solid phase change material, as schematically shown by arrows X. The one or more electric
heaters 420 are configured to provide a sufficient heat output to charge two or more slabs 350 of plastic solid to solid phase change material to the transient second heated phase, i.e. to the state where the slabs 350 are suitable for installation within the drawer 330 in the cart 310.
[0021] During testing and use of plastic solid to solid phase change material used in current banquet carts produced by the assignee of this application (which include solid to solid phase change material constantly maintained within the cart), a 1000 watt heater has been found to adequately heat a slab of plastic solid to solid phase change material to a suitable temperature (and to the second transient heated phase) in approximately one hour, with the heater only operating periodically to heat the slab as necessary. The design of the banquet cart currently used by the assignee of this application is disclosed in commonly owned U.S. Patent No. 7,102,103 (and included in pending grand-child U. S. S. N. 12/037,422, which is a continuation of U.S.S.N. 11/431 ,235, which is a continuation of U.S. Patent No. 7,102,103), the entirety of which is hereby fully incorporated by reference herein. One of skill in the art will understand after comprehending this disclosure (and the disclosure of commonly assigned U.S. 7,102,103) that one or more smaller capacity heaters 420 (i.e. on the order of between about 300-750 watts) may be used to heat the slabs 350 if more time to heat the slabs 350 is allowable than the one hour specification mentioned above, because the cabinet 410 is constructed (with suitable doors, gaskets, wall insulation etc.) such that substantially all heat generated by the electric heaters 420 ultimately is retained by the slabs 350 disposed within the cabinet 410. [0022] In some embodiments, the cabinet 410 may be configured to receive between about 2 and 20 slabs 350 of plastic solid to solid phase change material and provide a sufficient heat input to heat each slab to the second transient phase with one or more electric heaters 420 provided therein. By way of example, in embodiments with a capacity to receive and heat 20 slabs 350 simultaneously, 20 500 watt heaters (or the equivalent combined power output for a smaller number of heaters 420) may be provided to provide a sufficient heat input to heat each slab 350 to the second transient heated phase, while allowing the cabinet 410 to receive power through a conventional 208 volt, 50 amp
plugged current source. As can be understood, in other embodiments, the cabinet 410 may be configured to receive 5, 10, 15 or other suitable and convenient numbers of slabs 350 and simultaneously provide heat thereto (through the convection heat transfer generated by the fan 422) to change each slab 350 to the second transient heated state in an acceptable time and with acceptable power inputs. In still other embodiments, cabinets 410 may be configured to receive and heat greater than 20 slabs 350 simultaneously, where the commercial establishment has the capacity to provide higher voltages and/or current flows to the cabinet 410.
[0023] The cabinet 410 may include two or more racks 418 that are each configured to receive a slab 350 of plastic solid to solid phase change material. In some embodiments, each rack 418 is configured to position the slab 350 received thereon proximate to a flow of heated convection air from one or more of the plurality of conduits 424 to provide heat to the respective slab 350. In other embodiments, the cabinet 410 may include two or more sets of notches 419 or other similar structural components to allow the two or more slabs 350 to be mounted directly to the walls forming the cabinet 410 on the notches 419. In embodiments with notches 419 defined upon the cabinet 410 walls, the slabs 350 may be formed with opposed radially extending fingers 354 that are configured to ride upon the notches 419 to properly align each slab 350 within the cabinet 410. [0024] The cabinet 410 may be configured to remain in the kitchen or other preparation area of the facility so that the heated and phase changed slabs 350 of plastic solid to solid phase change material may be heated and then placed within the appropriate drawer 330 of the cart 310 in an area proximate to where the plates or trays of food are inserted into the internal volume 321 of the cart 310. In some embodiments, the cabinet 410 may be movable with wheels 413, casters, or the like, to allow the cabinet 410 to be transported from the kitchen or other preparation area to a remote area to provide for heated slabs 350 proximate to carts 310 that have been removed from the kitchen or preparation area for an extended period of time.
[0025] In some embodiments shown in FIG. 6, the cabinet 410 may additionally include an induction heater 450 unit that is configured to receive a
slab 350 of plastic solid to solid phase change material configured to receive heat from an induction heater. As known in the art, an induction heater 450 provides a rapidly changing magnetic field, which receives thereupon (or in close proximity to) a slab 350 that is configured with a significant amount of ferrous material disposed therein, which either has a large internal resistance, or is electrically connected with one or more resistors. The rapidly changing magnetic field produced by the induction heater 450 induces a significant current within the internal ferrous material which flows through the resistive material or resistors and generates heat in proportion to the current flow squared multiplied by the internal resistance. The heat generated within the slab 350 is conducted to the plastic solid to solid phase change material surrounding the resistive internal portion, which rapidly heats up the material until the material changes to the heated second transient state, discussed above. In some embodiments, the induction heater 450 may be disposed upon the top of the cart 410 and may heat two or more slabs simultaneously as discussed above. In still other embodiments, an induction heater 450 that is configured to simultaneously heat two or more slabs 350 may be provided as a stand alone component. As discussed above with other embodiments, the heated slabs 350 may be positioned within the drawers 330 in the cart 310 to provide a continuous long lasting input of heat to the internal volume 320 and the food disposed within the internal volume 320 of the cart 310.
[0026] While the preferred embodiments have been described, it should be understood that the disclosure is not so limited and modifications may be made without departing from the scope of the disclosure. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.
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