Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/647—Aspects related to microwave heating combined with other heating techniques
  • H05B6/6482—Aspects related to microwave heating combined with other heating techniques combined with radiant heating, e.g. infrared heating
  • H05B6/6485—Aspects related to microwave heating combined with other heating techniques combined with radiant heating, e.g. infrared heating further combined with convection heating
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
  • F24C7/00—Stoves or ranges heated by electric energy
  • F24C7/02—Stoves or ranges heated by electric energy using microwaves
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/6408—Supports or covers specially adapted for use in microwave heating apparatus
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/70—Feed lines
  • H05B6/707—Feed lines using waveguides
  • H05B6/708—Feed lines using waveguides in particular slotted waveguides
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/80—Apparatus for specific applications
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B2206/00—Aspects relating to heating by electric, magnetic, or electromagnetic fields covered by group H05B6/00
  • H05B2206/04—Heating using microwaves
  • H05B2206/046—Microwave drying of wood, ink, food, ceramic, sintering of ceramic, clothes, hair

Definitions

• the present invention relates to a multi-shelved oven having multiple heating means, including convection, microwave and radiant food heating means
• the oven disclosed herein relates primarily to ovens suitable for use in the commercial food service industry, such as fast food restaurants, and other food service application where there is great variety in the food products prepared, the need for speedy thermalization of food and space constraints While various oven designs are known and available for commercial food service applications, there still exists a need for an efficient and effective oven that allows for simultaneous cooking of different food products requiring different heat treatments
• Single cavity ovens have been designed heretofore that include microwave and convection heat transfer cooking means While such ovens meet the needs of certain commercial food service applications by providing rapid thermalization and cooking, the inability to cook different foods simultaneously with different heating conditions and cook cycles does not provide needed flexibility
• known combination ovens often require mechanical means to stir the microwave or move the food product in order to achieve even microwave heat transfer to the food product
• the present invention provides an oven that meets a need in the food service industry for an oven provides rapid heating/cooking and the ability to cook multiple food products simultaneously under different conditions and cook cycles Moreover, the ovens of the present invention provide a microwave heating means that does not require mechanical stirring of microwaves or movement of food products to achieve substantially uniform distribution of microwave energy into the cooking cavities of the oven
• an oven that includes a cooking chamber, a blower and a shelf disposed within the cooking chamber
• the shelf has a unique design in that it has an inlet opening and cavity in fluid communication with the blower and at least one opening in fluid communication with the cooking chamber through which temperature controlled air can flow into the cooking chamber to cook food by convection heating
• the oven further comprises a microwave heating source for heating food products within said cooking chamber, thereby providing multiple heating methods (convection and microwave)
• the microwave heating means includes a microwave source and wave guide through which microwaves travel.
• the wave guide includes a plurality of openings through which microwaves can pass into said cooking chamber.
• the openings in the wave guide are positioned to correspond with the predetermined minima or maxima for the microwave wavelength propagating within the wave guide That is the spacing of the wave guide openings occurs at multiples of predetermined minima and/or maxima for the microwaves within the guide generated by the microwave source, most commonly a magnetron.
• a heating element can be mounted within the cooking chamber, providing an additional heating means
• a movable, reflective stirrer is positioned above the heating element to reflect heat from the heating element toward a food product
• the shelf includes a plurality of louvers protruding from the top surface of the shelf for supporting a food receptacle, thereby allowing air to flow freely beneath the food product or receptacle
• the louvers have openings that direct temperature controlled air in a direction substantially parallel to the top of the shelf
• the cooking chamber comprises a first cooking cavity and a second cooking cavity and includes a first shelf and a second shelf
• the first shelf has an inlet opening and cavity in fluid communication with a blower and the second shelf has an inlet opening and cavity in fluid communication with a blower
• both the first and second shelves have at least one opening in fluid communication with the first cooking cavity and second shelf having at least one opening in fluid communication with said second cooking cavity, respectively
• microwave heating is provided in the first and second cavities through wave guides, preferably a pair of wave guides associated with each cavity
• the preferred wave guide arrangement again provides a wave guide having a predetermined minima and maxima and openings in the wave guide
• FIG 1 is front view of the oven (three cavity configuration)
• FIG 2 is a front view of the inte ⁇ or cooking chamber of the oven (three cavity configuration)
• FIG 3 is a front perspective view of the inte ⁇ or cooking chamber and portions of the convection heat transfer and microwave heat transfer systems of the oven (three cavity configuration)
• FIG 4 is a front perspective view of the interior cooking chamber and portions of the convection heat transfer and microwave heat transfer systems of the oven (three cavity configuration),
• FIG 5 is a front perspective view of the interior cooking chamber and portions of the convection heat transfer system of the oven (three cavity configuration), including the food product shelf,
• FIG 6 is a view of the interior cooking chamber depicting the electric heating element within the cooking chamber
• FIG 7 is a left side view of the oven with the left panel of the exterior cabinet removed to show portions of the convection heating system of the oven (three cavity configuration),
• FIG 8 is a perspective view of the food shelf which serves as a conduit through which temperature controlled air into the cooking chamber of the oven,
• FIG 9 A is a perspective view of an alternative embodiment of the shelf
• FIG 9B is a cross section view of the alternative embodiment of the shelf depicted in FIG 9A
• FIG 10 is a perspective view of a product support rack
• FIG 11 is a perspective view of an embodiment of an air delivery duct for the convection heat transfer system of the oven
• FIG 12 is a perspective view of a preferred alternative embodiment of an air delivery duct for the convection heat transfer system of the oven
• FIG 13A is a front view of a filter assembly for filtering air exiting the cooking chamber
• FIG 13B is side view of the filter assembly of FIG 13 A
• FIG 13C is schematic depiction of the accordion fold filter plate of the filter assembly of FIG 13A.
• FIG 14 is a side view of a bracket for supporting the filter assembly of FIG 13 A on the side wall of the interior cooking chamber of the oven
• FIG 15 is schematic depiction of a control system for the oven of the present invention (three cavity configuration)
• FIG 16 is a perspective view a two cavity configuration of the oven
• FIG 17 is a partial perspective view of the interior cooking chamber and microwave heating system for the oven (two cavity configuration)
• FIG 18 is a perspective view of the microwave heating system for the oven (two cavity configuration)
• FIG 19 is a partial perspective view of the cooking chamber and oven configuration with partial exhaust of temperature controlled air stream
• FIG 20 is a partial perspective view of the ambient air intake and partition chamber aspects of a preferred embodiment of the two cavity configuration of the oven.
• FIG 21 is a perspective view of the reflective stirrer of the present invention DETAILED DESCRIPTION OF THE INVENTION
• FIGS 1-23 The description of the invention provided below is made with reference to the drawings attached hereto The drawings have been consecutively numbered as FIGS 1-23
• Oven 10 includes an exterior cabinet 12 defined by exterior side walls, exterior top and bottom walls and an exterior rear wall Preferably said walls are constructed of a stainless steel material Hingedly secured to the front of the oven is door 14 which permits food products to be placed in and out of the interior of the oven A handle 16 with latching means is secured to door 14 to allow the door to be secured in a closed position during cooking
• the door 14 is designed by known conventional means for preventing microwave leakage from the chamber 18 while the door is closed Referring to FIGS.
• chamber 18 is defined by interior side walls 19 and 21, back wall 23, top wall 25 and bottom wall 27 (collectively the oven chamber interior walls)
• said oven chamber interior walls are constructed of a stainless steel material
• chamber 18 further comprises a plurality of cooking cavities 18a
• each shelf is designed to not only support a food product but is also designed as a conduit through which temperature-controlled (e g heated) gas (preferably air) passes and provides convection heating to food products within each oven cavity 18a
• each shelf has a top portion 31, a bottom portion 32, side portions 34 and 36, rear portion 38 and front portion 40, defining shelf
• the louvers are inverted and do not project from the top of the shelf, but instead project into the shelf cavity
• the louvers act like scoops within the shelf cavity
• a wire rack 900 (FIG 10) may be placed on the shelf to lift the food receptacle (or food) from the top surface of the shelf, thereby providing satisfactory convection heat transfer
• the top surface of the shelf 31a has vertically extending protrusions 50a, recessed areas or surfaces 46 and openings 48 disposed in the recesses areas
• the arrows shown in FIG 9B generally depict the direction of air travel into the shelf cavity 41a and through openings 48
• one advantage of the shelf design depicted in FIGS 9A and 9B is that when a pan or other food receptacle is placed on the shelf, heated air travels freely beneath the pan and between the louvers providing very effective convective heat transfer
• each blower assembly 60 comprises a blower housing 64, a blower wheel 66 and a shaft 68 operably connected to a motor which rotates each blower wheel
• each blower wheel is turned by a single axle 68 which is operably connected to a motor means
• a 1/10 horsepower motor has been found to be adequate
• a blower wheel of the forward inclined type has also been found to be adequate
• Air is drawn into the blower housing and is disposed into tapered ducts 62 which, as shown, are disposed between the cabinet side wall and the oven chamber side wall 19
• specific reference numerals are provided only with respect to the tapered duct which is in fluid communication with the lower shelf
• the features of the lower blower and duct assemblies are essentially identical to the middle and upper blower and duct assemblies and therefore desc ⁇ ptions for the latter are not repeated
• each tapered duct has a proximal end 162 and a dis
• air return openings 90 are provided in side wall 19 within each cooking cavity 18a for the return of gas from each cooking cavity to blowers 60 By providing air return ports within each cavity 18a, each cavity can function as an independent convection oven, thereby allowing cooking of different foods at different temperatures and on different cycles
• the air return openings 90 may be covered by a filter assembly 300 mounted to side wall 19 by a bracket 302 or other known means to prevent food particles, grease and other materials from escaping the cooking cavity through the return openings
• a preferred filter assembly 300 is shown in FIGS 13A-C and 14 and comprises a filter frame 304 which supports a perforated metal plate 306 that is folded in an accordion fashion thereby providing a greater surface area over which return air passes before exiting the cooking chamber through the return openings
• the temperature of the circulated air or gas can be controlled by any known means One suitable means to heat and control the temperature of the air is by well known electric heating rods 80 (1 e , Calrod
• duct 62 may have a constant taper from proximal end 162 to distal end 168 as shown in FIGS 3-5 and 7 or may have multiple degrees of taper as shown by the dashed lines in FIG 1 1
• duct 62 may have a dual taper configuration, which has been found to provide even air flow from the orifices along the length of the duct
• said duct has a first horizontal tapered portion 160 adjacent proximal end 162 and inlet opening 164 (i e , the opening where air from the blower enters the duct) and a second horizontal tapered portion 166 adjacent the distal end 168
• the first horizontal tapered portion 160 has a greater angle of taper than the second horizontal tapered portion 166 which has a lower slope
• the first horizontal tapered portion 160 extends approximately one-quarter to one-half of the length of
• an electric heating element 101 e.g., Calrod heating elements
• an electric heating element 101 may also be disposed adjacent the top of the oven cavity so as to provide a means for broiling food products disposed on the upper shelf (see FIGS 1, 2 and 6)
• the present oven also provides means for heating food product via microwave energy
• microwaves are disposed into the oven cavity through microwave openings 200 formed in the side wall 21 of the oven cavity
• Side wall 21 is disposed opposite of oven cavity side wall 19
• the type (i.e. power) of magnetron used is a matter of choice and is based on well known selection factors Use of 2450 MHz magnetrons were found suitable in the embodiment shown in FIGS. 16-18
• each magnetron 210 feeds microwaves into and through a conduit 212 associated with the particular magnetron assembly and through the openings 200 and into the oven cavity
• the openings 200 and conduit structure 212 are arranged such that a more uniform dispensing of microwave is provided within the oven cavity
• a preferred configuration for the openings 200 is shown in the figures Other configurations may also be determined and will vary according to the design and dimensions of the cooking cavity
• each cavity 18a has its own independent microwave source (i.e , magnetrons assemblies)
• magnetrons assemblies i.e , magnetrons assemblies
• each cavity 18a has its own independent microwave source
• Each wave guide includes a plurality of openings 404, preferably slots, through which the microwaves travel into the cooking cavity
• the slots 404 are spaced to provide substantially even microwave distribution along the length of the wave guide Specifically, the slots are spaced approximately at multiples of the calculated minima or maxima for the microwaves generated by the microwave source, i e magnetron
• the minima and maxima for a particular wave guide and magnetron are calculated by known means.
• slots 404 are preferably disposed at angles in relation to the length of wave guides which run generally from the back towards the front of each cavity.
• blowers assemblies 500 are preferably provided to cool the magnetrons 410 during operation.
• reciprocating reflective stirrers 600 are disposed above the heating elements at the top of heating chamber 18 for reflecting heat from the heating element toward the shelf below.
• the stirrers are made of a material that is also microwave reflective so that enhanced stirring of microwaves is achieved, thereby promoting evenness of cooking.
• a suitable stirrer material is stainless steel.
• the reflective stirrer 600 is operably connected to bearing 602 which is moved by link 604, which in turn is connected to a drive link 606 driven by motor 608.
• chamber 18 comprises two cooking cavities 18a and that two doors 700 are used to seal the oven.
• FIGS. 17-19 there is shown a exhaust opening 702 in blower housing 64 through which a portion of the temperature controlled gas is exhausted from the oven via stack (or conduit) 704.
• the exhausting of air from the system induces ambient air to be drawn through intake opening 706 disposed at the back of the oven.
• Ambient air is then drawn into partition chamber 708 disposed between the upper and lower cavities 18a.
• Air from partition chamber 708 is then drawn through openings 710 to both the upper and lower blower assemblies 60 which are in fluid communication with the partition chamber. Exhaust air flow and "make up" ambient air flow into the system is depicted by the arrows in FIGS.
• FIGS. 1 and 16 generally depict the control panel (or controller) 450 for the embodiments described herein.
• the controller 450 has the capability to control microwave heating power and cook cycle times, and is capable of being programmed for particular food cooking applications.
• the controller 450 control the convective heat transfer aspects of the invention (e.g., blowers 60 and heating elements) and the reflective stirrers described above.

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• 2000
  • 2000-04-19 AU AU44741/00A patent/AU773859B2/en not_active Ceased
  • 2000-04-19 DE DE60033022T patent/DE60033022T2/de not_active Expired - Fee Related
  • 2000-04-19 ES ES00926174T patent/ES2278604T3/es not_active Expired - Lifetime
  • 2000-04-19 CA CA002371147A patent/CA2371147A1/fr not_active Abandoned
  • 2000-04-19 BR BR0009905-8A patent/BR0009905A/pt not_active IP Right Cessation
  • 2000-04-19 AT AT00926174T patent/ATE352180T1/de not_active IP Right Cessation
  • 2000-04-19 EP EP00926174A patent/EP1172022B1/fr not_active Expired - Lifetime
  • 2000-04-19 WO PCT/US2000/010624 patent/WO2000064219A1/fr active IP Right Grant
  • 2000-04-19 KR KR1020017013286A patent/KR20020002432A/ko not_active Application Discontinuation
  • 2000-04-19 JP JP2000613228A patent/JP2002542601A/ja active Pending

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