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EP1016325B1 - Four a micro-ondes - Google Patents

Four a micro-ondes Download PDF

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Publication number
EP1016325B1
EP1016325B1 EP98905388A EP98905388A EP1016325B1 EP 1016325 B1 EP1016325 B1 EP 1016325B1 EP 98905388 A EP98905388 A EP 98905388A EP 98905388 A EP98905388 A EP 98905388A EP 1016325 B1 EP1016325 B1 EP 1016325B1
Authority
EP
European Patent Office
Prior art keywords
cavity
section
side wall
cross
microwave oven
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
EP98905388A
Other languages
German (de)
English (en)
Other versions
EP1016325A1 (fr
Inventor
P. O. Risman
Dan Carlsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Whirlpool Corp
Original Assignee
Whirlpool Corp
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
Application filed by Whirlpool Corp filed Critical Whirlpool Corp
Publication of EP1016325A1 publication Critical patent/EP1016325A1/fr
Application granted granted Critical
Publication of EP1016325B1 publication Critical patent/EP1016325B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H05B6/6426—Aspects relating to the exterior of the microwave heating apparatus, e.g. metal casing, power cord
    • 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

Definitions

  • the present invention relates to a microwave oven and feeding of the same with microwaves.
  • Microwave ovens for domestic use and the like are usually made with an essentially rectangularly parallelepipedal cavity. This is due to both manufacturing considerations and a conventional view of what microwave ovens should look like. Although it is possible to a certain extent to calculate which so-called cavity modes are obtained in a rectangularly parallelepipedal cavity, it has proved difficult to achieve a reasonably symmetrical heating pattern in such a cavity, in particular when it is fed sideways. So-called field stirrers or rotating bottom plates for the load are often employed with a view to improving the heating pattern.
  • An object of the present invention is to make possible an improved heating pattern in a rectangularly parallelepipedal cavity in a microwave oven.
  • Another object of the invention is to make possible such an improved heating pattern without employing moving parts, such as field stirrers or rotating bottom plates.
  • a further object of the invention is to provide a method which allows improved configuration of a rectangularly parallelepipedal cavity with respect to the resulting heating pattern.
  • the heating pattern in a rectangularly parallelepipedal oven cavity can be advantageously affected by the arrangement of a non-constant horizontal cross-section in the cavity.
  • the cross-section changes concerned do not change the general rectangularly parallelepipedal shape and cannot be compared to wall embossing, rounding of corners, etc. which are conventionally done in order to adjust the rectangularly parallelepipedal dimensions for manufacturing reasons and generally to facilitate the manufacture of the cavity and improve mechanical stability.
  • the invention is thus based on the insight that the relative phase and amplitude of the modes in the cavity can be modified favourably in and for heating pattern levelling-out or equalisation by means of well-judged, relatively modest vertical changes to the horizontal cross-section of the cavity. Put another way, by making these kinds of cross-section changes, one can control the mode balance with respect to both relative amplitudes and phase of the modes involved so that a more even heating pattern is achieved.
  • the cross-section change can be achieved by a cavity side wall being made at least partly inward sloping.
  • a method for microwave feeding of a rectangularly parallelepipedal microwave oven cavity which means that in and for equalisation of the effect of the microwaves in the cavity, the mode balance of the microwave field is affected by the cavity being given, in relation to the horizontal cavity bottom cross-section, at least in the upper part of the cavity an upwardly decreasing horizontal cross-section.
  • the feeding of microwaves is advantageously done through an opening in a cavity side wall opposing the inward sloping wall, the microwave feeding preferably taking place along an area closely adjacent to the cavity ceiling.
  • microwaves through an opening in the cavity ceiling, also in this case suitably extended in a direction parallel to the sloping side wall.
  • a method for acting on the heating pattern which is obtained by means of microwaves fed into an rectangularly parallelepipedal microwave oven cavity, changes to the heating pattern being achieved by a cavity side wall being caused to slope inwards at least in its upper part, so that the cavity has an upwardly decreasing horizontal cross-section in relation to the available bottom cross-section of the cavity.
  • a chosen cavity width it is possible on the basis of a chosen cavity width to vary the horizontal cross-section change by changing the degree and/or extent of the inward slope of the cavity wall and observing the resulting changes to the heating pattern. It will be appreciated that by carrying out such changes of the inward slope of the side wall for a number of different cavity widths, it is possible to determine the cavity width and side wall inward slope combination which provides the best heating pattern.
  • a microwave oven comprising a rectangularly parallelepipedal cavity and a microwave source connected thereto for feeding microwaves into the cavity, the cavity, in relation to its available bottom cross-section, having an upwardly decreasing horizontal cross-section at least in the upper part of the cavity.
  • the cavity preferably has a side wall, which at least partly slopes inwards in order to provide the desired horizontal cross-section decrease.
  • the inward slope is in the upper part of the side wall, while the lower part of the side wall is vertical and preferably at least 50 mm high.
  • the inward slope of the upper part of the side wall does not need to extend all the way up to the cavity ceiling, rather the side wall can have a short vertical ceiling connection part terminating at the top.
  • the sloping side wall part is plane, other configurations are also possible.
  • the slope of the side wall is preferably over essentially the whole actual wall width and advantageously over at least about half the wall height.
  • the slope of the side wall can be made within a deep-drawn portion of the side wall, so that the joining with the back wall and the front of the oven can be done with vertical joints.
  • the slope can advantageously be over about 85% of the total depth of the cavity.
  • a microwave oven according to the invention suitably has a horizontal cross-section which is approximately square.
  • the "depth” is preferably between about 85% and about 120% of the "width”.
  • the height of the cavity from the bottom plate or the cavity bottom to the cavity colling is from about 160 mm to about 230 mm.
  • the embodiment of a microwave oven according to the invention illustrated in Figs 1 and 2 comprises an outer casing 1 which is outlined only and an oven cavity 2, which is closed by means of a front door 3.
  • the cavity 2 is formed by a horizontal cavity bottom 4, a horizontal cavity ceiling 5, a vertical back cavity wall 6, a front vertical wall on the inside of the front door 3 and two cavity side walls 7 and 8.
  • the right side wall 7 in Figs 1 and 2 is vertical and provided with a microwave unit for feeding microwaves into the oven cavity through a slot-shaped, rectangular side wall opening 10, such as will be described in more detail below.
  • the left side wall 8 in Figs 1 and 2 slopes inward somewhat and thus forms an angle of about 3° to vertical. Consequently, the cavity is rectangularly parallelepipedal except for the inward slope of the side wall 8. However, the inward slope is so small that it cannot be considered that there is any essential deviation from the rectangularly parallelepipedal shape, except for the resulting microwave characteristics.
  • All the cavity defining wall surfaces in this embodiment are generally plane, although the sloping side wall 8 joins the cavity ceiling at the top with a vertical wall part 11 of a small height.
  • the microwave unit 9 comprises in a manner known per se a magnetron 13 and a waveguide device 14 connected thereto for feeding microwaves into the cavity through the feeder slot 10.
  • this slot is usually elongated and rectangular and arranged at the top and in the midpoint on the side wall 7 in the connection area to the cavity ceiling 5.
  • the oven can comprise a microwave-transparent bottom plate 16 for a foodstuff load 17. If desired, this plate can be rotatable. However, it has been found that the oven constructed according to the invention despite the sideways feeding of microwaves gives a heating pattern which is so even that a rotating bottom plate cannot be considered necessary.
  • Examples of typical dimensions for an oven for domestic use according to Figs 1 and 2 are B1 - about 333 mm, B2 - about 325 mm; cavity height (over the bottom plate) - about 185 mm; and cavity depth - about 370 mm.
  • Fig. 3 shows a schematic vertical cross-section of the same kind as in Fig. 2, which illustrates another embodiment of an oven according to t.he invention. The latter differs from the oven according Lo Figs 1 and 2 with respect to the design of the sloping side wall and the microwave feeding.
  • the sloping side wall 8' in Fig. 2 has a lower part 21, which is vertical, and an upper inward-sloping part 22.
  • the inward slope begins about halfway up the side wall and amounts to about 6°.
  • the horizontal cross-section decrease adjacent to the cavity ceiling is here somewhat larger than in the oven according to Figs 1 and 2, typically about 10 mm.
  • Fig. 3 the microwave feeding is done through a rectangular ceiling slot 10', which is centrally located in the cavity ceiling 5 and whose long side is parallel to the cavity side walls 7 and 8' and which is fed by the intermediary of a waveguide device 14' arranged on the cavity ceiling.

Landscapes

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

Abstract

L'invention concerne un four à micro-ondes, et un procédé pour alimenter ce four en micro-ondes. La cavité de four rectangulairement parallélépipède (2) comporte une paroi latérale (8) dont la pente est légèrement inclinée vers l'intérieur pour donner une coupe transversale horizontale, se réduisant en direction du haut. La sélection d'une pente appropriée, permet de modifier l'équilibre de mode dans la cavité, de manière à obtenir la meilleure égalisation du schéma de chauffage.

Claims (10)

  1. Four à micro-ondes comprenant une cavité parallélépipède rectangulaire et une source de micro-ondes permettant d'introduire des micro-ondes dans la cavité (2) connectée à celle-ci,
    caractérisé en ce que la cavité a, par rapport à sa section en coupe de fond, une section en coupe horizontale rétrécissant vers le haut, la cavité étant parallélépipède rectangulaire à l'exception de l'inclinaison vers l'intérieur d'une paroi latérale de la cavité (8, 8'), adjacente à une paroi verticale frontale à l'intérieur d'une porte frontale (3), l'inclinaison vers l'intérieur ne commençant pas plus qu'à mi-hauteur de la paroi latérale (8, 8').
  2. Four à micro-ondes selon la revendication 1, caractérisé en ce que la paroi latérale de la cavité (7), qui fait face à ladite paroi latérale inclinée (8, 8'), est munie d'au moins une ouverture en fente (10) permettant d'introduire les micro-ondes, située au sommet.
  3. Four à micro-ondes selon la revendication 1 ou 2, caractérisé en ce qu'il comporte une ouverture en fente (10') dans le plafond de la cavité (5) pour l'introduction des micro-ondes, l'ouverture en fente s'étendant de manière transversale par rapport à un plan vertical, dans lequel la largeur de la cavité horizontale rétrécit vers le haut.
  4. Four à micro-ondes selon l'une quelconque des revendications 1 à 3, caractérisé en ce que la section en coupe horizontale de la cavité a une profondeur allant d'environ 85 % à environ 120 % de la largeur.
  5. Four à micro-ondes selon l'une quelconque des revendications 1 à 4, caractérisé en ce que la largeur de la section au sommet de la cavité (2) est dans l'intervalle allant d'environ 315 mm à environ 335 mm et en ce que la largeur de la section en coupe est d'environ 8 à environ 15 mm plus large que le fond.
  6. Four à micro-ondes selon l'une quelconque des revendications 1 à 5, caractérisé en ce que la largeur en section en coupe au sommet de la cavité (2) est dans l'intervalle allant d'environ 385 mm à environ 410 mm et en ce que la largeur en section en coupe est d'environ 8 à environ 15 mm plus large au niveau du fond.
  7. Four à micro-ondes selon la revendication 5 ou 6, caractérisé en ce que la cavité (2) a une hauteur allant d'environ 150 mm à environ 220 mm.
  8. Procédé permettant d'alimenter en micro-ondes une cavité de four à micro-ondes parallélépipède rectangulaire, caractérisé en ce que dans et pour l'égalisation de l'effet des micro-ondes dans la cavité, l'équilibre des modes du champ de micro-ondes est affecté par le fait qu'on donne à la cavité, par rapport à la section en coupe du fond de la cavité horizontale, une section en coupe horizontale rétrécissant vers le haut au moins dans la partie supérieure de la cavité, la section en coupe horizontale décroissante étant obtenue en inclinant vers l'intérieur une paroi latérale de la cavité (8, 8') au moins à mi-hauteur, ladite paroi latérale de cavité étant adjacente à une paroi verticale frontale à l'intérieur d'une porte frontale.
  9. Procédé selon la revendication 8, caractérisé en ce que les micro-ondes sont introduites dans la cavité par au moins une ouverture (10) située au sommet dans une paroi latérale de cavité (7) située en face de la paroi latérale inclinée vers l'intérieur (8, 8').
  10. Procédé selon la revendication 8 ou 9, caractérisé en ce que les micro-ondes sont introduites dans la cavité par une ouverture (10') dans le plafond de la cavité (5).
EP98905388A 1997-02-10 1998-02-03 Four a micro-ondes Expired - Lifetime EP1016325B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9700448A SE513645C2 (sv) 1997-02-10 1997-02-10 Förfarande vid mikrovågsmatning samt mikrovågsugn avpassad för förfarandet
SE9700448 1997-02-10
PCT/EP1998/000553 WO1998035533A1 (fr) 1997-02-10 1998-02-03 Four a micro-ondes

Publications (2)

Publication Number Publication Date
EP1016325A1 EP1016325A1 (fr) 2000-07-05
EP1016325B1 true EP1016325B1 (fr) 2007-01-03

Family

ID=20405727

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98905388A Expired - Lifetime EP1016325B1 (fr) 1997-02-10 1998-02-03 Four a micro-ondes

Country Status (12)

Country Link
EP (1) EP1016325B1 (fr)
JP (1) JP2001511298A (fr)
KR (1) KR20000070907A (fr)
CN (1) CN1154399C (fr)
AU (1) AU738511B2 (fr)
BR (1) BR9807566A (fr)
DE (1) DE69836819T2 (fr)
ES (1) ES2276455T3 (fr)
SE (1) SE513645C2 (fr)
SK (1) SK103799A3 (fr)
TR (1) TR199901915T2 (fr)
WO (1) WO1998035533A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE511668C2 (sv) * 1998-03-16 1999-11-08 Whirlpool Co Mikrovågsugn
GB9916432D0 (en) * 1999-07-13 1999-09-15 Microgaming Systems Ansalt Identification of computers
KR100396765B1 (ko) * 2000-08-23 2003-09-02 엘지전자 주식회사 전자렌지의 균일가열구조
JP2004265616A (ja) * 2003-02-05 2004-09-24 Matsushita Electric Ind Co Ltd マイクロ波加熱装置
CN102037782B (zh) * 2008-04-15 2013-06-05 松下电器产业株式会社 微波加热装置
DE102016221447A1 (de) * 2016-11-02 2018-05-03 BSH Hausgeräte GmbH Haushalts-Gargerät

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2814708A (en) * 1952-01-05 1957-11-26 Raytheon Mfg Co Microwave ovens
GB944993A (en) * 1960-11-14 1963-12-18 Radyne Ltd Improvements in or relating to microwave ovens
DE1515149A1 (de) * 1964-04-04 1969-08-14 Siemens Elektrogeraete Gmbh Garraum eines HF-Strahlungsherdes
GB1114938A (en) * 1965-10-01 1968-05-22 Hirst Microwave Heating Ltd Microwave-heating ovens
JPS532349Y2 (fr) * 1974-02-28 1978-01-21
US3991295A (en) * 1974-05-20 1976-11-09 Matsushita Electric Industrial Co., Ltd. Microwave oven with symmetrically positioned microwave stirrers
IT213611Z2 (it) * 1988-02-17 1990-01-22 Eurodomestici Ind Riunite Forno, in particolare a micro onde, con faccia frontale inclinata.
US6462320B1 (en) * 1996-05-17 2002-10-08 Technology Finance Corporation (Proprietary) Limited Dielectric heating device employing microwave heating for heating or cooking substances

Also Published As

Publication number Publication date
JP2001511298A (ja) 2001-08-07
AU738511B2 (en) 2001-09-20
SE9700448L (sv) 1998-08-11
WO1998035533A1 (fr) 1998-08-13
DE69836819T2 (de) 2007-10-11
CN1154399C (zh) 2004-06-16
SE513645C2 (sv) 2000-10-16
ES2276455T3 (es) 2007-06-16
BR9807566A (pt) 2000-02-01
TR199901915T2 (xx) 1999-10-21
SE9700448D0 (sv) 1997-02-10
KR20000070907A (ko) 2000-11-25
EP1016325A1 (fr) 2000-07-05
SK103799A3 (en) 2000-08-14
DE69836819D1 (de) 2007-02-15
AU6099098A (en) 1998-08-26
CN1247014A (zh) 2000-03-08

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