WO2015101396A1 - Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné - Google Patents

Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné Download PDF

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Publication number
WO2015101396A1
WO2015101396A1 PCT/EP2013/078150 EP2013078150W WO2015101396A1 WO 2015101396 A1 WO2015101396 A1 WO 2015101396A1 EP 2013078150 W EP2013078150 W EP 2013078150W WO 2015101396 A1 WO2015101396 A1 WO 2015101396A1
Authority
WO
WIPO (PCT)
Prior art keywords
door
inwardly bent
microwave
cooking cavity
metal
Prior art date
Application number
PCT/EP2013/078150
Other languages
English (en)
Inventor
Metin Gur
Mehmet Baris Gocer
Yalcin Yaman
Original Assignee
Arcelik Anonim Sirketi
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 Arcelik Anonim Sirketi filed Critical Arcelik Anonim Sirketi
Priority to CN201380081936.5A priority Critical patent/CN105850227A/zh
Priority to PCT/EP2013/078150 priority patent/WO2015101396A1/fr
Priority to EP13823958.7A priority patent/EP3090604B1/fr
Publication of WO2015101396A1 publication Critical patent/WO2015101396A1/fr

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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
    • H05B6/647—Aspects related to microwave heating combined with other heating techniques
    • H05B6/6473—Aspects related to microwave heating combined with other heating techniques 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
    • F24C15/00—Details
    • F24C15/02—Doors specially adapted for stoves or ranges
    • F24C15/021—Doors specially adapted for stoves or ranges sealings for doors or transparent panel
    • 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
    • H05B6/6402—Aspects relating to the microwave cavity
    • 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
    • H05B6/6414—Aspects relating to the door of the 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
    • H05B6/76—Prevention of microwave leakage, e.g. door sealings
    • H05B6/763—Microwave radiation seals for doors

Definitions

  • the present invention relates to a door for use in a domestic cooking oven which has a microwave facility.
  • the present invention particularly relates to a door for use in a combination convection/microwave oven.
  • the microwave cooking technology enables rapid and energy efficient cooking of food.
  • the food is subjected to microwave radiation which causes polarized molecules in the food to vibrate and produce heat.
  • the microwave radiation easily penetrates into the food, the entire food can be instantly and uniformly heated. Thereby the food can be quickly and uniformly cooked.
  • a drawback of the microwave cooking technology is that the oven must be properly sealed to prevent the microwave radiation from leaking to an outside.
  • the cooking cavity acts as a Faraday cage.
  • a small fraction of the microwave radiation typically leaks through the apertures between the door and the cooking cavity.
  • the microwave radiation which leaks to an outside poses severe risks to the health of users and can cause burns and permanent damages. Therefore, compliance with the maximum permissible leakage limit is of utmost importance. This leakage limit is generally prescribed by the competent authorities.
  • a commonly known technique is to seal the aperture between the door and the cooking cavity by utilizing a microwave sealing choke which is usually mounted on a periphery of the door so as to oppose a metal front wall around the opening of the cooking cavity.
  • the microwave sealing choke includes a plurality of resonant cavities which receive the microwave radiation which propagates along the metal front wall to an outside. The radiation is attenuated by the resonant cavities.
  • EP1333703A2 discloses a microwave oven which has a microwave sealing choke.
  • the microwave sealing choke is arranged onto the periphery of the door so as to oppose the metal front wall.
  • microwave cooking technology Another drawback of the microwave cooking technology is that it is not possible to obtain gastronomic results that can be typically obtained by conventional cooking ovens which utilize convective heat transfer. Therefore, the so called “combination ovens” have devised which allow cooking by convective heat transfer and/or microwave radiation. Thereby, the user can selectively apply any of the above-mentioned cooking technologies to the food to achieve the best cooking results.
  • the temperatures reached during microwave cooking are relatively lower than the temperatures reached during cooking by convective heat transfer. Therefore, in a combination convection/microwave oven, when the food is cooked by convective heat transfer, the temperature reached inside the cooking cavity reaches relatively high levels in particular during baking, grilling or the like in comparison to sole microwave cooking.
  • the heat produced in the cooking cavity is radiated off by conductive heat transfer to the front metal wall, and therefrom to the critical electrical components like the user-interface, the control unit or the like which are typically installed into the front wall. Certain temperature limits must be observed for the proper operation of these electrical components. Therefore, the electrical components parts must be suffiently cooled. However, the cooling process increases the energy consumption of the oven.
  • the front wall could be modified to become less heat conductive.
  • this impairs electrical conductivity of the front wall and, in turn, the microwave sealing performance degrades.
  • An objective of the present invention is to provide a door suitable for use in a combination convection/microwave oven and a combination convection/microwave oven which overcome the aforementioned drawbacks of the prior art and which is improved both in thermal and microwave leakproofing.
  • the door of the present invention is suitable for use in a combination convection/ microwave oven which has a front wall and a cooking cavity enclosed by a cavity wall.
  • a first metal lining which forms the cavity wall and a second metal lining which forms the front wall respectively have an inwardly bent first segment and an inwardly bent second segment which abut each other outside the cooking cavity circumferentially around an opening of the cooking cavity.
  • the door of the present invention has an inner metal wall which includes a straight portion and an inwardly bent portion.
  • the straight portion is configured to circumferentially oppose directly the inwardly bent first segment and the inwardly bent second segment through a gap whereas the inwardly bent portion is configured to circumferentially protrude into the cooking cavity along an edge of the opening so as to directly oppose the first metal lining through a gap.
  • the inwardly bent portion contributes via the straight portion to the sealing performance of a microwave sealing choke formed on the lateral metal walls of the door which is configured to circumferentially oppose the front wall through a gap.
  • the inwardly bent portion, the straight portion and microwave sealing choke arranged on the lateral metal walls effectively act as a single microwave sealing choke.
  • the overall shape of the inwardly bent portion is convex or alternatively concavo-convex.
  • a penetration depth of the inwardly bent portion which protrudes into the cooking cavity is equal to or less than a critical value where the inwardly bent portion starts to function like a waveguide. This is determined with respect to a cut-off frequency of the inwardly bent portion.
  • the critical value largely depends, among others, on a main frequency of the magnetron which is typically around 2.45 GHz. In a version of this embodiment, the critical value is about eight millimeters, and an optimum sealing performance is attained the when the penetration depth ranges from two millimeters to eight millimeters.
  • the inwardly bent first segment and the inwardly bent second segment are spot welded at predetermined intervals circumferentially around the opening of the cooking cavity. Thereby the heat conductivity is effectively reduced.
  • the inwardly bent first segment and the inwardly bent second segment are connected by mechanical means such as screws, snap-fittings, claws, or the like.
  • the door has a monolithic metal frame. Thereby a manufacturing of the door has been simplified. In addition, this improves the overall microwave sealing performance.
  • a combined convection/microwave cooking oven has been provided in which the front wall has been protected from excessive thermal radiation of the cooking cavity.
  • a microwave sealing choke has been provided which reduces microwave leakage below a maximum permissible leakage limit. Thereby, optimum operation conditions for the electrical components have been established without compromising the microwave sealing performance.
  • Figure 1 - is a schematic cross sectional partial side view of a combination convection/microwave oven which has a door according to an embodiment of the present invention, taken along a vertical direction.
  • the door (1) is suitable for use in a combination convection/microwave oven (2).
  • the combination convection/microwave oven (2) comprises a cooking cavity (3) which is enclosed by a cavity wall (4), wherein the cooking cavity (3) has an opening (6), and wherein the cavity wall (4) is formed from a first metal lining (5), the door (1) which is pivotably arranged to open/close the opening (6) of the cooking cavity (3), a front wall (7) which is formed from a second metal lining (8), one or more than one electrical resistance (not shown) for convectively heating food inside the cooking cavity (3), a microwave magnetron (not shown) for radiative heating of food inside the cooking cavity (3), a user interface (not shown) for receiving user inputs and for audibly and/or visually outputting information and a control unit (not shown) for controlling the electrical resistance, the magnetron and the user interface .
  • the first metal lining (5) and the second metal lining (8) respectively have an inwardly bent first segment (9) and an inwardly bent second segment (10) which abut each other outside of the cooking cavity (3) and circumferentially around the opening (6).
  • the door (1) comprises lateral metal walls (11) which include a microwave sealing choke (12) configured to circumferentially oppose the front wall (7) through a first gap (13).
  • the door (1) of the present invention further comprises an inner metal wall (14) which includes a straight portion (15) and an inwardly bent portion (17).
  • the straight portion (15) is configured to circumferentially oppose directly the inwardly bent first segment (9) and the inwardly bent second segment (10) through a second gap (16).
  • the inwardly bent portion (17) is configured to circumferentially protrude into the cooking cavity (3) along an edge (18) of the opening (6) so as to directly oppose the first metal lining (5) through a third gap (19).
  • the overall shape of the inwardly bent portion (17) is convex. In an alternative embodiment, the overall shape of the inwardly bent portion (17) is concavo-convex.
  • the lateral metal walls (11) and the inner metal wall (14) are integrally formed from a third metal lining (20).
  • the microwave sealing choke (12), the straight portion (15), and the inwardly bent portion (17) constitute a monolithic metal door frame (21).
  • the monolithic door frame (21) is formed by pressing and bending. Thereby, a manufacturing process of the door (1) becomes simple and cost effective.
  • the inner metal wall (14) further includes a perforated metal screen portion (22).
  • the preformation is suffiently large to enable a user to observe the cooking cavity (3) and sufficiently small to keep the microwave leakage below permissible limits i.e., maximum 1.4 mW/cm ⁇ 2.
  • the perforated metal screen portion (22) is circumferentially surrounded by the inwardly bent portion (17).
  • the perforated metal screen portion (22) is outwardly offset relative to the inwardly bent portion (17) by a predetermined distance. Thereby an inner volume of the cooking cavity (4) is increased, and a microwave sealing performance of the inwardly bent portion is increased.
  • the perforated metal screen portion (22) and the straight portion (15) lie in a same plane.
  • the inwardly bent portion (17) includes one or more than one tapered shoulder (23) and an arc-shaped shoulder (24).
  • the tapered shoulders (23) adjoin the perforated metal screen portion (22) whereas an arc-shaped shoulder (24) joins the straight portion (15).
  • the overall shape of the inwardly bent portion (17) is concavo-convex.
  • the arc-shaped shoulder (24) and the edge (18) have matching outlines in order to improve the microwave sealing performance.
  • a penetration depth (D) of the inwardly bent portion (17) which protrudes into the cooking cavity (3) ranges between two millimeters to eight millimeters. This specific range largely depends, among others, on a size and shape of the cooking cavity (3). Above eight millimeters, the inwardly bent portion (17) may start functioning like a waveguide, and thus the sealing performance may degrade. Similarly below 2 millimeters the sealing performance may be insufficient. Thus an optimum sealing performance is attained the when the penetration depth (D) ranges from two millimeters to eight millimeters.
  • the microwave sealing choke (12) includes a plurality of LC resonant cavities (25) which are successively formed at predetermined intervals along a circumferential direction on the lateral walls.
  • Each LC resonant cavity has one or more than one slot (26) which opposes the front wall (7).
  • the resonant frequency is adjusted in accordance with a main frequency of the magnetron. A typical value for the magnetron frequency is 2.45 GHz.
  • the present invention also provides a combination convection/microwave oven (2) which has the door (1).
  • the inwardly bent first segment (9) and the inwardly bent second segment (10) are spot welded at predetermined intervals circumferentially around the opening (6) of the cooking cavity (3). Throughout the predetermined interval, the first/second segments (9, 10) are not continually welded. Thereby, the conductive heat transfer can be considerably reduced.
  • the predetermined interval largely depends on the size of the front wall (7), the cavity wall and the wattage of the oven (2).
  • the predetermined interval which separates two successive spot-welding is equal to or less than four centimeters.
  • the predetermined interval is about three centimeters. In a version of this embodiment the predetermined interval is exactly three centimeters.
  • control unit and the user interface are arranged on the front wall (7).
  • the electrical components of the control unit and the user interface can be operated within optimum temperature limits.
  • control unit has a plurality of modes including at least three modes.
  • the first mode is suitable for cooking food by convective heat transfer only.
  • the second mode is suitable for cooking food by microwave radiation only.
  • the third mode is suitable for cooking food by convective heat transfer and microwave radiation in combination.
  • a combined convection/microwave cooking oven has been provided in which the front wall has been protected from excessive thermal radiation of the cooking cavity.
  • a microwave sealing choke has been provided which reduces microwave leakage below a maximum permissible leakage limit.
  • optimum operation conditions for the electrical components have been established without compromising microwave sealing.
  • the oven can be reliably operated even at the highest designated operation temperatures. Hence the temperature of the exposed parts and the internal parts can be safely kept below critical threshold values.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electric Ovens (AREA)
  • Constitution Of High-Frequency Heating (AREA)

Abstract

La présente invention concerne une porte (1) convenant à une utilisation dans un four à convection/micro-ondes combiné (2) qui comporte une cavité de cuisson (3) entourée par une paroi de cavité (4) qui est faite d'une première chemise métallique (5), la cavité de cuisson (3) ayant une ouverture (6) et une paroi avant (7) qui est faite d'une seconde chemise métallique (8), la première chemise métallique (5) et la seconde chemise métallique (8) ayant respectivement un premier segment courbé vers l'intérieur (9) et un second segment courbé vers l'intérieur (10) qui sont en appui l'un contre l'autre à l'extérieur de la cavité de cuisson (3) de façon circonférentielle autour de l'ouverture (6).
PCT/EP2013/078150 2013-12-30 2013-12-30 Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné WO2015101396A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN201380081936.5A CN105850227A (zh) 2013-12-30 2013-12-30 用于组合式对流/微波炉的改进的微波防漏门
PCT/EP2013/078150 WO2015101396A1 (fr) 2013-12-30 2013-12-30 Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné
EP13823958.7A EP3090604B1 (fr) 2013-12-30 2013-12-30 Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2013/078150 WO2015101396A1 (fr) 2013-12-30 2013-12-30 Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné

Publications (1)

Publication Number Publication Date
WO2015101396A1 true WO2015101396A1 (fr) 2015-07-09

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Application Number Title Priority Date Filing Date
PCT/EP2013/078150 WO2015101396A1 (fr) 2013-12-30 2013-12-30 Porte étanche aux micro-ondes améliorée pour four à convection/micro-ondes combiné

Country Status (3)

Country Link
EP (1) EP3090604B1 (fr)
CN (1) CN105850227A (fr)
WO (1) WO2015101396A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015223022A1 (de) 2015-11-23 2017-05-24 BSH Hausgeräte GmbH Haushaltsgargerät

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4053731A (en) * 1974-06-14 1977-10-11 Amana Refrigeration, Inc. Microwave energy oven seal
USRE31637E (en) * 1977-05-13 1984-07-31 Sanyo Electric Co., Ltd. Combination microwave and gas oven
JPS625595A (ja) * 1985-06-28 1987-01-12 松下電器産業株式会社 高周波加熱装置
FR2756617A1 (fr) * 1996-11-29 1998-06-05 Electrolux Juno Kuchentechnik Four menager comprenant une garniture d'etancheite entre le moufle et la vitre interne de la porte
EP1333703A2 (fr) * 2002-01-30 2003-08-06 Lg Electronics Inc. Four à micro-ondes comportant une structure d'étanchéité ainsi que le four à micro-ondes en étant équipé
US20050057006A1 (en) * 2001-11-19 2005-03-17 BSH Bosch und Siemens Hausgeräte GmbH Door sealing strip and cooking device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4053731A (en) * 1974-06-14 1977-10-11 Amana Refrigeration, Inc. Microwave energy oven seal
USRE31637E (en) * 1977-05-13 1984-07-31 Sanyo Electric Co., Ltd. Combination microwave and gas oven
JPS625595A (ja) * 1985-06-28 1987-01-12 松下電器産業株式会社 高周波加熱装置
FR2756617A1 (fr) * 1996-11-29 1998-06-05 Electrolux Juno Kuchentechnik Four menager comprenant une garniture d'etancheite entre le moufle et la vitre interne de la porte
US20050057006A1 (en) * 2001-11-19 2005-03-17 BSH Bosch und Siemens Hausgeräte GmbH Door sealing strip and cooking device
EP1333703A2 (fr) * 2002-01-30 2003-08-06 Lg Electronics Inc. Four à micro-ondes comportant une structure d'étanchéité ainsi que le four à micro-ondes en étant équipé

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015223022A1 (de) 2015-11-23 2017-05-24 BSH Hausgeräte GmbH Haushaltsgargerät

Also Published As

Publication number Publication date
EP3090604B1 (fr) 2019-09-04
CN105850227A (zh) 2016-08-10
EP3090604A1 (fr) 2016-11-09

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