EP0006997A1 - Four à micro-ondes - Google Patents

Four à micro-ondes Download PDF

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Publication number
EP0006997A1
EP0006997A1 EP79101781A EP79101781A EP0006997A1 EP 0006997 A1 EP0006997 A1 EP 0006997A1 EP 79101781 A EP79101781 A EP 79101781A EP 79101781 A EP79101781 A EP 79101781A EP 0006997 A1 EP0006997 A1 EP 0006997A1
Authority
EP
European Patent Office
Prior art keywords
microwave
muffle
oven according
opening
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.)
Granted
Application number
EP79101781A
Other languages
German (de)
English (en)
Other versions
EP0006997B1 (fr
Inventor
Johann Klement
Werner Schnabel
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.)
Individual
Original Assignee
Individual
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 DE19782830658 external-priority patent/DE2830658C2/de
Priority claimed from DE19782834368 external-priority patent/DE2834368C2/de
Application filed by Individual filed Critical Individual
Publication of EP0006997A1 publication Critical patent/EP0006997A1/fr
Application granted granted Critical
Publication of EP0006997B1 publication Critical patent/EP0006997B1/fr
Expired 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
    • H05B6/76—Prevention of microwave leakage, e.g. door sealings

Definitions

  • the invention relates to a microwave oven with a microwave-tightly closable oven muffle connected to a high-frequency oscillator, with a rotatable shaft guided through an opening in a metallic muffle wall, e.g. a circulating air blower, and with a microwave seal provided in the area of the opening in the form of a metal disk arranged at a short distance parallel to the muffle wall and connected to the shaft.
  • a metallic muffle wall e.g. a circulating air blower
  • a microwave seal for a microwave oven has become known (DE-OS 27 i5 636), which consists in that a metallic disk is mounted on the drive shaft of a circulating air blower directly outside the shaft opening in the corresponding oven wall, i.e. outside the cooking chamber, which prevents it should allow microwave energy to escape from the cooking chamber through the shaft opening to the outside.
  • a simple gap is usually not sufficient to completely prevent the escape of microwave energy, especially not if the gap between the pane and the outside of the wall is unevenly along the circumference of the pane, which is usually the case if the muffle wall is heated very strongly during operation, the disk, however, remains relatively cool. As a result of the material stress caused by the strong heating, the wall plate tends to bend very easily.
  • the present invention has for its object to design a microwave oven of the type mentioned so that the effect of the microwave seal is improved without significant design effort.
  • a preferably annular groove-like microwave pocket is provided which extends from the opening.
  • the radial length of the microwave line between the disk and the adjacent muffle wall is preferably the length of the microwave pocket in each case approximately 1/4 of the wavelength of the microwaves.
  • the disk has a hub connected to the shaft, in which an essentially axially parallel, to which the muffle wall having the opening is open, the microwave pocket forming the annular groove is provided.
  • the microwave bag is also in one for fan wheels only conventional heating operation anyway existing part of the fan wheel, namely housed in the wheel hub to save space.
  • the disk and the hub are fastened to the part of the shaft which projects into the muffle interior. In this way it is ensured that, in particular in conventional or combined heating operation, the muffle wall and the disk heat up to the same extent, so that a one-sided warping of the disk or wall combined with a partial enlargement of the gap can practically not take place.
  • the disc serves as the radial base plate of a circulating air impeller, to which the fan blades are attached, the edge hub of which contains the annular groove.
  • a metallic heat transport disc lying between the latter and the muffle wall or the cover plate is attached to the rotor of the external rotor blower motor, which is preferably a short distance of 1-2 mm in front of the muffle wall or Cover plate is arranged and forms a micro-wave-tight gap with a radial length of about 1/4 of the wavelength of the microwaves, a particularly intensive effect is achieved when the heat transfer plate is coated on the surface facing the muffle wall with a ferrite material, preferably with ferrite rubber.
  • a metallic cup washer is attached to the outer surface of the muffle wall or cover plate having the opening to form an annular groove-like microwave pocket that is only open to the shaft between the inner surface and the outer wall surface.
  • a microwave cut-off filter consisting of a microwave guide slot and a microwave pocket
  • a capacitive microwave seal in the form of a shaft attached and on the muffle wall closely adjacent metallic disc is provided.
  • the capacitive microwave seal which is designed in the form of a disk rotating with the shaft and is in itself not sufficient to prevent microwaves from emerging from the opening, is suitable in combination with the microwave blocking filter arranged inside the muffle in order to effectively prevent any residual microwaves from radiating outside the muffle room.
  • a microwave cut-off filter is provided in the interior of the muffle following the opening, consisting of a microwave slot and microwave pocket, and that outside the muffle following the opening on the Shaft is a can-shaped, a microwave pocket forming, open to the opening hollow body.
  • This can-shaped hollow body forms, together with the microwave slot provided in the interior of the muffle, a second microwave guide path with a blocking filter effect, with a total length of 1/2 the wavelength of the microwaves, the microwave slot and the microwave pocket each having a length of 1/4 the wavelength of the microwaves.
  • FIG. 1 shows the rear part of a microwave oven designed according to the invention, 1 denoting the tubular muffle body, which laterally and upwards and downwards delimits the muffle interior, into which a muffle rear wall, generally designated 3, is inserted or welded.
  • the cover plate 6 has a central opening 8 through which the drive shaft 9 of the rotor 10 of an external rotor blower motor 11 is guided with play.
  • the electric blower motor 11 is located outside the muffle, while a blower wheel 12 is fastened or mounted on the end of the shaft 9 projecting into the cooking space 2 by means of a screw 13 or the like.
  • the impeller 12 has a radial base plate 14 with an integrally formed central hub 15, the base plate 14 having an inner ring region 16 and an outer ring region 17 set apart from the muffle rear wall 3.
  • a baffle plate 20 is attached to bent portions 19 of the muffle rear wall 3, which has air intake openings 21 in the center and air outlet openings 22 in the vicinity of the muffle walls.
  • the chain-dotted circle describes a microwave seal explained below, by which it is prevented that the microwave energy introduced into the cooking space 2 from a high-frequency oscillator, not shown, via a waveguide, also not shown, can reach the outside through the opening 8 in the muffle rear wall 3.
  • a microwave line 23 is provided, formed by a gap between the metallic cover plate 6, which is connected to the muffle body via the seal 7, and the inner ring region of the disk-like base plate 14 of the impeller 12, the distance between the cover plate 6 and the inner disk 16 being approximately Is 1-1.5 mm.
  • the hub 15 of the impeller 12 there is an axially parallel annular groove 24 which is open towards the opening 8 and which represents a microwave pocket.
  • the ring groove or microwave pocket 24 and the microwave line 23 form a microwave trap, the length a of the microwave line and the length b of the microwave pocket being equal to a quarter of the wavelength of the microwaves, in the exemplary embodiment 32 mm in each case. In this way, a microwave energy minimum is created in the area of the opening 8.
  • the distance between the disk 16 and the inner surface of the cover plate is 1 - 1.5 mm, while the clear width c of the microwave pocket or the annular groove 24 is about 7 mm.
  • the hub has a projection 25 protruding through the opening 8 in the cover plate 6.
  • a metal cup disk 26 which serves, inter alia, as a heat sink is fastened to the outside of the cover plate, such that it fits in with the cover plate 6 and thus with the muffle is electrically conductive connection.
  • This washer 26 forms an annular groove-like microwave pocket 27 with the length a, which is only open toward the shaft 9 and which, in addition to the microwave pocket 24 or instead of the latter, contributes to improving the microwave seal.
  • the microwave trap described in the area of the opening 8 enables the fan space in which the fan wheel 12 is located to be separated from the rest of the muffle interior 2 by a normal baffle plate 20 with relatively wide blow-out openings 22 used in conventional convection ovens. without having to take care that the baffle plate is already microwave-proof.
  • the blower unit described can be used universally, that is to say also in ovens with conventional electrical heating or circulating air heating, the heat transport disk 28 being able to dissipate the operating heat of the blower motor 11 and the cup disk 26 as a heat sink element,
  • the rear part of a microwave oven is shown, 100 denoting the muffle rear wall of a muffle, not shown, which is accessible through a front-side loading opening.
  • the muffle rear wall 100 has a recess 102 in the center, onto which a metallic cover plate 103 is placed from the muffle interior and thereby closed.
  • the cover plate 103 is in metallic contact with the muffle rear wall 100, for example in that the sealing strips 104 are interspersed with metal mesh.
  • the cover plate 102 has a central opening 105 through which the drive shaft 106 of an external rotor blower motor 107 is guided with radial play.
  • the electric blower motor 107 is located outside the muffle, while a blower wheel 108 is fastened or mounted on the end of the shaft 106 projecting into the cooking space by means of a screw 109 or the like.
  • the fan wheel 108 has a radial base plate 110 with an integrally formed central hub 111, the base plate 110 having an inner ring region 112 and an outer ring region 113 which is offset from the muffle wall.
  • Fan blades 114 are located on the periphery of the base plate 110.
  • a conventional baffle plate not shown, is fastened directly in front of the impeller 108 and has air intake openings in the center and air outlet openings in the vicinity of the muffle wall.
  • the arrangement shown contains means to prevent the microwave energy introduced into the cooking space by a high-frequency oscillator (not shown) via a waveguide (also not shown) from passing through the opening 105 in the muffle rear wall 108.
  • a microwave blocking filter consisting of a microwave guide slot 115 between the muffle rear wall 100, or cover plate 103 and the inner ring region 112 of the disk-like base plate 110, and a microwave pocket 116, formed by an axially parallel annular groove in the hub 111 of the fan wheel 108 that is open to the opening 105.
  • the length a of the microwave guide slot 115 and the microwave pocket 116 a 1/4 wavelength of the microwaves, that is to say a total of 1/2 wavelength, the opening 105 being located at the point within the microwave cut-off filter at which the through Reflection standing wave in the microwave pocket has an energy minimum (zero current crossing).
  • a plate-shaped protective plate 117 is placed on the outside of the cover plate 103 and is in metallic contact with the cover plate 103 or with the muffle rear wall 100.
  • a capacitive microwave seal is provided on the outside of the muffle rear wall 100, or the cover plate 103, in the form of a metallic disc 118 fastened on the shaft 106 and closely adjacent to the cover plate 103, which has a radial length a and a i / 4 of the wavelength of the microwaves.
  • the disk 118 has a clear distance of 1.5 mm from the cover plate 103.
  • a can-shaped hollow body 119 is fixed, which is open at the point 120 towards the opening 105.
  • the hollow body 119 has a radial inside length a of 1/4 of the wavelength of the microwaves and represents an additional microwave pocket which, together with the microwave guide slot 115, forms a microwave blocking filter.
  • the metallic hollow body 119 can be arranged so close to one another on the cover plate 103 that a capacitive microwave seal similar to FIG. 2 also results.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
EP79101781A 1978-07-12 1979-06-06 Four à micro-ondes Expired EP0006997B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE2830658 1978-07-12
DE19782830658 DE2830658C2 (de) 1978-07-12 1978-07-12 Mikrowellenofen
DE2834368 1978-08-04
DE19782834368 DE2834368C2 (de) 1978-08-04 1978-08-04 Mikrowellenofen

Publications (2)

Publication Number Publication Date
EP0006997A1 true EP0006997A1 (fr) 1980-01-23
EP0006997B1 EP0006997B1 (fr) 1983-01-19

Family

ID=25774985

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79101781A Expired EP0006997B1 (fr) 1978-07-12 1979-06-06 Four à micro-ondes

Country Status (2)

Country Link
US (1) US4303817A (fr)
EP (1) EP0006997B1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0670587A1 (fr) * 1994-02-25 1995-09-06 Fusion Systems Corporation Dispositif d'enlèvement de films par plasme muni d'un piège à micro-ondes
EP3343110A4 (fr) * 2015-08-26 2018-09-05 Panasonic Intellectual Property Management Co., Ltd. Cuiseur

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4556771A (en) * 1984-07-19 1985-12-03 Raytheon Company Microwave feed for common cavity oven
DE3838447A1 (de) * 1988-11-12 1990-05-17 Standard Elektrik Lorenz Ag Umluftgeblaese fuer backoefen
US5021621A (en) * 1990-04-17 1991-06-04 Martha Demmer Microwave oven having integral mixing assembly
KR920014362A (ko) * 1990-12-21 1992-07-30 강진구 턴테이블 구동부의 전자파 차폐구조
US6118112A (en) * 1999-03-04 2000-09-12 Amana Company, L.P. Choke knob for coaxial microwave feed
CN1329692C (zh) * 2003-04-25 2007-08-01 乐金电子(天津)电器有限公司 微波炉的搅拌扇组件
CN100455904C (zh) * 2004-09-20 2009-01-28 乐金电子(天津)电器有限公司 微波炉炉腔的上面板结构
US7414229B2 (en) * 2005-01-04 2008-08-19 Hellmann Michael G Disposable microwave food shield
US7586068B2 (en) * 2005-01-04 2009-09-08 Peter Shaw Disposable microwave food shield
EP2247160B1 (fr) * 2009-05-02 2012-11-28 Electrolux Home Products Corporation N.V. Dispositif d'étanchéité aux micro-ondes de l'ouverture autour d'un arbre rotatif
DE102017117055A1 (de) * 2017-07-27 2019-01-31 Topinox Sarl Lüfterrad und Gargerät

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB612409A (en) * 1943-04-02 1948-11-12 Sperry Gyroscope Co Inc Improvements in or relating to ultra high frequency apparatus for interchanging energy between a concentric transmission line and a circular wave guide
US2470805A (en) * 1941-09-12 1949-05-24 Emi Ltd Means for preventing or reducing the escape of high-frequency energy
FR1557372A (fr) * 1967-03-20 1969-02-14
US3431381A (en) * 1966-03-29 1969-03-04 Tappan Co The Dual stirrer assembly
FR1571130A (fr) * 1967-06-28 1969-06-13
FR2291595A1 (fr) * 1974-11-18 1976-06-11 Siemens Ag Dispositif destine a empecher l'energie perturbatrice hf de rayonner par les ouvertures pratiquees dans les parois des appareils utilisant les hautes frequences

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137442A (en) * 1975-05-22 1979-01-30 Sharp Kabushiki Kaisha High-frequency oven having a browning unit
JPS5247702A (en) * 1975-10-14 1977-04-15 Fujitsu Ltd Process for producing a recording medium of magnetic iron oxide
US4053730A (en) * 1976-05-17 1977-10-11 Litton Systems Inc. Microwave oven shaft seal
US4211909A (en) * 1978-05-15 1980-07-08 Sanyo Electric Co., Ltd. Combination microwave and gas oven
JPS5843875B2 (ja) * 1977-07-11 1983-09-29 松下電器産業株式会社 高周波加熱装置用ヒ−タ装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2470805A (en) * 1941-09-12 1949-05-24 Emi Ltd Means for preventing or reducing the escape of high-frequency energy
GB612409A (en) * 1943-04-02 1948-11-12 Sperry Gyroscope Co Inc Improvements in or relating to ultra high frequency apparatus for interchanging energy between a concentric transmission line and a circular wave guide
US3431381A (en) * 1966-03-29 1969-03-04 Tappan Co The Dual stirrer assembly
FR1557372A (fr) * 1967-03-20 1969-02-14
FR1571130A (fr) * 1967-06-28 1969-06-13
FR2291595A1 (fr) * 1974-11-18 1976-06-11 Siemens Ag Dispositif destine a empecher l'energie perturbatrice hf de rayonner par les ouvertures pratiquees dans les parois des appareils utilisant les hautes frequences

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0670587A1 (fr) * 1994-02-25 1995-09-06 Fusion Systems Corporation Dispositif d'enlèvement de films par plasme muni d'un piège à micro-ondes
EP3343110A4 (fr) * 2015-08-26 2018-09-05 Panasonic Intellectual Property Management Co., Ltd. Cuiseur
US10697643B2 (en) 2015-08-26 2020-06-30 Panasonic Intellectual Property Management Co., Ltd. Cooker

Also Published As

Publication number Publication date
EP0006997B1 (fr) 1983-01-19
US4303817A (en) 1981-12-01

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