WO2006128212A1 - Dispositif ameliore servant a rechauffer un produit alimentaire - Google Patents

Dispositif ameliore servant a rechauffer un produit alimentaire Download PDF

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Publication number
WO2006128212A1
WO2006128212A1 PCT/AU2006/000635 AU2006000635W WO2006128212A1 WO 2006128212 A1 WO2006128212 A1 WO 2006128212A1 AU 2006000635 W AU2006000635 W AU 2006000635W WO 2006128212 A1 WO2006128212 A1 WO 2006128212A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
magnetron
conduit
heating device
recess
Prior art date
Application number
PCT/AU2006/000635
Other languages
English (en)
Inventor
Stuart Brown
David William Mclean
Kane Walker
Original Assignee
Ipv Pty Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2005902894A external-priority patent/AU2005902894A0/en
Application filed by Ipv Pty Limited filed Critical Ipv Pty Limited
Publication of WO2006128212A1 publication Critical patent/WO2006128212A1/fr

Links

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
    • H05B6/70—Feed lines
    • H05B6/707—Feed lines using 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
    • H05B6/66—Circuits
    • H05B6/68—Circuits for monitoring or control
    • H05B6/687—Circuits for monitoring or control for cooking
    • 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
    • H05B6/72—Radiators or antennas
    • 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
    • H05B6/808—Microwave heating adapted for vending machines
    • 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
    • H05B2206/044—Microwave heating devices provided with two or more magnetrons or microwave sources of other kind

Definitions

  • the invention relates generally to an apparatus for heating a food product and more particularly to a food product heating device employing a microwave field.
  • the invention has been primarily developed for use in stand-alone commercial or domestic microwave ovens and will be described hereinafter with reference to that application. However, it will be appreciated that the invention is not limited to that particular application and is also applicable, for example, to hot food vending machines.
  • Known domestic and commercial microwave ovens include at least one magnetron for forming a microwave field to heat food products prior to delivery to a customer.
  • a dipole antenna in the form of an uncased screw embedded in a rotatable carousel within an oven enclosure of the machine is employed to increase the intensity of the microwave field.
  • intensity of the microwave field can be further increased by using a cased dipole antenna.
  • known uncased screw-type antennas are used, the screw must be accurately adjusted and set within the carousel to tune the microwave field within the oven enclosure.
  • known antennas are exposed, there is a tendency for unskilled operators to attempt to adjust the antenna, which can cause undesirable or even dangerous effects.
  • a commercial microwave oven is shown in the Applicant's earlier PCT Patent
  • This oven includes a microwave energy focusing apparatus within the oven enclosure, which tapers outwardly from a smaller end adjacent the oven enclosure wall to a larger end within the oven enclosure.
  • this earlier focusing apparatus can allow excessive feedback or reflected energy to return back to the magnetron, thereby reducing the service life of the magnetron.
  • the Applicant has found that using an inwardly tapered focussing device, which tapers inwardly from its end adjacent the oven enclosure toward its other end inside the oven enclosure, reduces feedback to the magnetron in some oven enclosure designs.
  • known focusing apparatus can be relevantly difficult to manufacture and assemble.
  • known focusing apparatus usually require an installer to attach fastening means within the oven enclosure. This can be difficult, as access inside the oven enclosure is usually very restricted.
  • the present invention provides a dipole antenna for intensifying a microwave field in a food product heating device, said antenna including: an antenna housing; a recess in the housing; and an electrically conductive element within the recess, wherein the conductive element is enveloped by the housing.
  • the antenna includes a retaining cap for retaining the conductive element within the recess. More preferably, the cap includes an air vent to facilitate pressure equalisation between an area within the recess and an area external to the recess.
  • the housing is formed of a substantially electrically insulative material. More preferably, the material is polytetrafluoroethylene. However, in alternative embodiments, another microwave safe insulative material is used, such as high melting point plastics material or ceramic.
  • the electrically conductive element is elongate and is of larger diameter at one longitudinal end then at the opposite longitudinal end.
  • the electrically conductive element is a stainless steel or zinc plated steel screw. More preferably, the screw is around 26mm in overall length and has a minor diameter of around 6mm.
  • the dimensional characteristics of the conductive element are preferably determined based on the food product type being heated and the configuration of the oven in which the antenna is used.
  • the present invention provides a carousel for a food product heating device employing a microwave field, the carousel including: a base adapted for rotation; a supporting plate engageable with the base for supporting a food product to be heated; a recess within the plate; and the dipole antenna as defined above removably located within the recess for intensifying the microwave field.
  • the present invention provides a microwave energy focussing apparatus for a food product heating device including a magnetron for emitting microwave energy, the apparatus including: a conduit extending from an interior wall of the heating device adjacent the magnetron, the conduit having a first axial end adapted for connection to the heating device wall and a second axial end extending toward an interior region of the oven enclosure, wherein the conduit tapers inwardly from the first axial end toward the second axial end.
  • a mounting flange is provided at the first axial end of the conduit to facilitate connection of the conduit to the heating device wall. More preferably, pilot holes are provided in the mounting flange to permit connection of the conduit to the heating device wall using fasteners installed from a position external to the heating device.
  • the focussing apparatus is constructed from folded sheet steel. More preferably, the conduit is substantially rectangular in transverse cross-section. In a preferred form, adjacent sides of the conduit are of different dimensions when measured in a direction transverse to a longitudinal axis of the conduit.
  • one of the sides of the conduit extends substantially perpendicular to the heating device wall.
  • three of the sidewalls of the conduit taper inwardly from the first axial end toward the second axial end and the fourth side extends substantially perpendicularly from the heating device wall.
  • the present invention provides a method of monitoring cooking performance in a food product heating device including a magnetron for emitting microwave energy, said method comprising the steps of: determining a value indicative of a current across the magnetron; determining a difference between the determined value and a predetermined optimum value; and outputting a signal if the determined difference falls outside an acceptable range.
  • cooking system parameters such as cooking time or the intensity of the microwave energy, are adjusted depending on the determined difference to compensate for non-optimal cooking efficiency.
  • I dro p a difference between the measured current across the magnetron and a normal operating current across the magnetron (A).
  • the cooking time is adjusted only if I d rop > 0.2 A.
  • the predetermined value corresponds to a value indicative of optimal cooking efficiency.
  • the determined difference is used to assess serviceability of said magnetron. More preferably, a signal indicative of magnetron failure is output if said determined difference falls outside an acceptable range after 10 seconds have elapsed since the magnetron was actuated.
  • the acceptable range is preferably between 0 Amps and around +/- 1 Amps from a normal operating current, or more preferably, between 0 Amps and around 2 Amps from a normal operating current.
  • an error signal is also output if the magnetron fails to draw a minimum current of around 4 Amps after 10 seconds have elapsed since the magnetron was actuated.
  • Fig. 1 is a cross-sectional side view of an embodiment of a hot food product vending machine
  • Fig. 2 is an exploded perspective view of the carousel of Fig. 1;
  • Fig. 3A is a perspective view and Fig. 3B is a side elevation of one of the microwave energy focussing apparatus of Fig 1;
  • Fig. 4 is a perspective view of an alternative embodiment of the focussing apparatus shown in Figs. 3 A and 3B;
  • Fig. 5 is a logic diagram detailing an embodiment of a control system for a hot food vending machine. Detailed Description of the Preferred Embodiments
  • a commercial microwave oven 100 for heating a food product which in the preferred embodiment is a frozen pie P.
  • the oven 100 includes an oven enclosure 102 that has one (1000 Watt) upper magnetron 104 and two (800 Watt) side magnetrons 106 and 108 respectively, which are located externally of the enclosure 102.
  • Each of the magnetrons 104,106 and 108 has an associated focusing apparatus 110, 112 and 114 respectively, which are located within the oven enclosure 102.
  • the focussing apparatus 110, 112 and 114 taper from a larger end adjacent to their respective magnetron 104, 106 or 108 to a smaller end inside the enclosure 102 to focus the microwave energy from the magnetrons 104, 106 and 108 towards the pie P which is, during heating, positioned atop a carousel, designated generally by the reference numeral 116, which will be described in more detail below.
  • the oven enclosure 102 is similar to known household microwave ovens, except for the addition of the magnetrons 104 and 106 and the focussing apparatus 110, 112 and 114.
  • the carousel 116 has a substantially truncated conical external shape with a large annular base surface 118, a smaller circular support surface 120 and an outwardly downwardly sloping side surface 122 therebetween.
  • the carousel 116 is formed from two components, namely a polyethylene hollow base portion 124 and a teflon top plate 126.
  • the base portion 124 sits on, and in use is rotated by, the oven's internal electric motor driven base plate 127, which are well known.
  • the top plate 126 has a central rebate 127 to assist locating the pie P thereon as the pie P slides into the oven enclosure 102.
  • the diameter of the rebate 127 matches the size of the pie base.
  • the top plate 126 also includes a stepped cylindrical aperture 128 for mounting a dipole antenna 130.
  • the antenna 130 includes an electrically insulative housing 131 formed from polytetrafluoroethylene (PTFE, commonly sold under the trade mark "TEFLON").
  • the housing 131 includes a substantially cylindrical shaft 134 with a central bore (not shown) for receiving an electroconductive element 136.
  • the shaft 134 is slidingly engageable with the mounting aperture 128 in the top plate 126 and with a cylindrical bore 138 in the carousel 116.
  • An enlarged head 140 is provided at an upper end of the shaft 134.
  • the head 140 is receivable within a rebated portion defined by the stepped aperture 128 in the top plate 126 to provide a flat supporting surface for the pie P.
  • the electroconductive element 136 is tapered toward an upper end of the bore (not shown) in the insulative housing 131.
  • the element 136 is preferably formed of stainless steel or galvanised steel, but can be formed of other conductive materials.
  • the electroconductive element 136 is a screw of around 26mm in overall length and having minor diameter of around 6mm. However, the specific dimensional characteristics of the conductive element for a particular oven are determined based on the food product type being heated and the configuration of the oven.
  • the head 142 of the screw 136 is located at a lower end of the bore (not shown) in the housing 131 and the distal end 143 of the shaft of the screw is located toward the upper end of the housing bore (not shown).
  • An electrically insulative retaining cap 144 is also provided for retaining the element 136 within the aperture 132.
  • the cap includes an air vent 146 to facilitate pressure equalisation between an area within the housing bore (not shown) and an area external to the bore.
  • the antenna 130 serves to assist in focusing the microwave energy emitted from the focusing apparatus 110, 112 and 114, which are themselves directed towards the (elevated) heating position of the pie P when atop the carousel 116.
  • the modular form of the dipole antenna 130 allows it to be pre-configured for use in specific oven configurations. In this manner, a user can simply purchase an antenna that has been pre-configured for their oven environment, thereby removing the need for adjusting the position of the antenna on-site, as was required with prior art antennas. Moreover, because the conductive element is encased in the antenna housing, there is less inducement for a user to tamper with the conductive element.
  • the use of the antenna housing 131 also allows a standardised external antenna shape to be provided, despite inner configuration between antennas being different. In other words, even though differently sized and/or shaped conductive elements are used in different antennas, the external appearance of these antennas will be the same. It will be appreciated that this feature simplifies manufacture, as top plates of various shapes and sizes can be used with various antennas by simply providing all of the top plates with a mounting aperture complementary with the standardised antenna housing. Similarly, interchanging of antennas is facilitated by the modular design, which allows the antenna to easily be changed by sliding out one antenna and replacing it with a differently configured antenna.
  • the focussing apparatus 110, 112, 114 are formed from sheet metal folded into a tubular conduit 150 of generally rectangular cross- section.
  • the conduits 110, 112 and 114 taper from a larger end adjacent to their respective magnetron 104, 106 or 108 to a smaller end inside the enclosure 102.
  • three of the sides of the conduit 150 taper inwardly toward the smaller end.
  • the fourth side extends generally perpendicularly to an internal wall 151 of the oven enclosure 102.
  • a mounting flange 152 with pilot holes 153 is provided at the larger end of the conduit 150 to facilitate connection of the conduit to the oven wall 151.
  • the pilot holes 153 are configured and positioned to conveniently allow fasteners to be installed from a position external to the oven enclosure 102.
  • a cooking performance monitoring system is also provided for the heating device 100 to ensure that an optimally heated pie P is delivered to the customer.
  • a logic diagram of the system is shown in Fig. 5. The system relies on monitoring the current across each of the magnetrons 104, 106 and 108 and comparing the measured currents to respective optimum values for the current across each of the magnetrons. If the measured current is less than the optimum current, then the cooking time can be increased to compensate for a lower than optimum microwave field intensity. Conversely, if the current is higher than optimum, for example due to a power fluctuation, then the cooking time can be reduced to compensate for higher than optimum microwave field intensity. In this way, the system automatically ensures that an optimally heated product is delivered to the customer.
  • the cooking time is adjusted using the following expression:
  • Idrop a difference between a measured current across the magnetron and a predetermined optimum current across the magnetron (A). To prevent adjustments being made for inconsequential current deviations, the cooking time is adjusted only if I dro p > 0.2 Amps.
  • the measured current across the magnetron 104, 106 and 108 is also used to assess serviceability of the magnetron. This is achieved by comparing the measured current to an optimum current. If the difference between the measured and optimum currents is greater than around +/- 1.5 Amps after 10 seconds have elapsed since the magnetron was actuated, then a signal indicative of magnetron failure is output. An error signal is also output if the magnetron fails to draw a minimum current of around 4 Amps after 10 seconds have elapsed since the magnetron was actuated.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electric Ovens (AREA)
  • Constitution Of High-Frequency Heating (AREA)

Abstract

Antenne dipôle (130) servant à intensifier un champ micro-onde dans un dispositif de réchauffement (100) de produit alimentaire. Cette antenne (130) comporte un boîtier (131), un évidement pratiqué dans le boîtier et un élément conducteur (136) à l'intérieur de l'évidement. Cet élément conducteur (136) est enveloppé par le boîtier (130). L'invention concerne également d'autres améliorations apportées à ce dispositif.
PCT/AU2006/000635 2005-06-03 2006-05-15 Dispositif ameliore servant a rechauffer un produit alimentaire WO2006128212A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2005902894A AU2005902894A0 (en) 2005-06-03 Improvements in an apparatus for heating a food product
AU2005902894 2005-06-03

Publications (1)

Publication Number Publication Date
WO2006128212A1 true WO2006128212A1 (fr) 2006-12-07

Family

ID=37481119

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2006/000635 WO2006128212A1 (fr) 2005-06-03 2006-05-15 Dispositif ameliore servant a rechauffer un produit alimentaire

Country Status (1)

Country Link
WO (1) WO2006128212A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3182798A1 (fr) * 2015-12-18 2017-06-21 CONEY International k.s Appareil a micro-ondes
CN108567111A (zh) * 2017-03-14 2018-09-25 德国福维克控股公司 烹调至少一个食品的系统

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0432190A (ja) * 1990-05-25 1992-02-04 Toshiba Corp 高周波加熱調理装置
JPH04137481A (ja) * 1990-09-28 1992-05-12 Toshiba Corp マグネトロン駆動電源
JP2001012749A (ja) * 1999-06-30 2001-01-19 Toshiba Corp 電子レンジ
WO2002069767A1 (fr) * 2001-03-01 2002-09-12 Ipv Pty Limited Appareil permettant de rechauffer un produit alimentaire et dispositifs chauffants et ensemble d'alimentation associes
JP2003115371A (ja) * 2001-10-05 2003-04-18 Matsushita Electric Ind Co Ltd マイクロ波発生装置
JP2003115374A (ja) * 2001-10-05 2003-04-18 Matsushita Electric Ind Co Ltd 高周波加熱装置及びマグネトロン駆動制御方法
JP2003229244A (ja) * 2002-02-04 2003-08-15 Sanyo Electric Co Ltd 電子レンジ
JP2004095432A (ja) * 2002-09-02 2004-03-25 Toshiba Corp 電子レンジ
US20040256384A1 (en) * 2003-05-16 2004-12-23 The Ferrite Company, Inc. Microwave radiating applicator with reduced sensitivity to surrounding media
JP2005122926A (ja) * 2003-10-14 2005-05-12 Tokyo Denshi Kk 導波管型マイクロ波加熱装置

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0432190A (ja) * 1990-05-25 1992-02-04 Toshiba Corp 高周波加熱調理装置
JPH04137481A (ja) * 1990-09-28 1992-05-12 Toshiba Corp マグネトロン駆動電源
JP2001012749A (ja) * 1999-06-30 2001-01-19 Toshiba Corp 電子レンジ
WO2002069767A1 (fr) * 2001-03-01 2002-09-12 Ipv Pty Limited Appareil permettant de rechauffer un produit alimentaire et dispositifs chauffants et ensemble d'alimentation associes
JP2003115371A (ja) * 2001-10-05 2003-04-18 Matsushita Electric Ind Co Ltd マイクロ波発生装置
JP2003115374A (ja) * 2001-10-05 2003-04-18 Matsushita Electric Ind Co Ltd 高周波加熱装置及びマグネトロン駆動制御方法
JP2003229244A (ja) * 2002-02-04 2003-08-15 Sanyo Electric Co Ltd 電子レンジ
JP2004095432A (ja) * 2002-09-02 2004-03-25 Toshiba Corp 電子レンジ
US20040256384A1 (en) * 2003-05-16 2004-12-23 The Ferrite Company, Inc. Microwave radiating applicator with reduced sensitivity to surrounding media
JP2005122926A (ja) * 2003-10-14 2005-05-12 Tokyo Denshi Kk 導波管型マイクロ波加熱装置

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DATABASE WPI Week 199225, Derwent World Patents Index; Class X25, AN 1992-205779, XP003004828 *
DATABASE WPI Week 200120, Derwent World Patents Index; Class Q74, AN 2001-194769, XP003004825 *
DATABASE WPI Week 200339, Derwent World Patents Index; Class V05, AN 2003-410096, XP003004829 *
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DATABASE WPI Week 200534, Derwent World Patents Index; Class X25, AN 2005-327952, XP003004824 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3182798A1 (fr) * 2015-12-18 2017-06-21 CONEY International k.s Appareil a micro-ondes
WO2017102374A1 (fr) * 2015-12-18 2017-06-22 Coney International K.S. Appareil à micro-ondes
CN108567111A (zh) * 2017-03-14 2018-09-25 德国福维克控股公司 烹调至少一个食品的系统
CN108567111B (zh) * 2017-03-14 2022-06-24 德国福维克控股公司 烹调至少一个食品的系统

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