US3651300A - Microwave heating apparatus with radiation control and monitoring - Google Patents

Microwave heating apparatus with radiation control and monitoring Download PDF

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Publication number
US3651300A
US3651300A US109303A US3651300DA US3651300A US 3651300 A US3651300 A US 3651300A US 109303 A US109303 A US 109303A US 3651300D A US3651300D A US 3651300DA US 3651300 A US3651300 A US 3651300A
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Prior art keywords
heating apparatus
accordance
microwave heating
antenna
radiation
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US109303A
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English (en)
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Duane B Haagensen
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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    • 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
    • H05B6/6417—Door interlocks of the microwave heating apparatus and related circuits
    • 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

  • ABSTRACT A radiation safety device located about the entrance to a microwave oven is comprised of a wave trough-type of transmission line within which a printed circuit cross-polarized antenna is disposed to permit induction of radiation of either transverse electric or transverse magnetic waves into propagation circuits containing both dissipative and conductive elements for reducing environmental radiation leakage.
  • This invention relates to electronic heating apparatus and more particularly to a safety device for controlling environmental microwave radiation.
  • oven door interlocks for compliance with the requirements of the Radiation Control Act has also met with limited success. Since these interlocks are only able to insure the door being in a mechanically closed position and in many instances are not fail-safe, no protection is afforded when a door seal becomes worn or defective.
  • a general object of the present invention is to provide a means of controlling and monitoring environmental radiation from microwave heating apparatus.
  • a more specific object of the invention is to provide a microwave oven with an integral dissipative, conductive and detecting system which uses multiple reduction principles to insure a fail-safe control of environmental radiation.
  • a further object of the invention is to control environmental radiation from a microwave oven in which the control is sensitive to cross-polarized electric fields.
  • a more specific aim of the invention is to provide a resistive cross-polarized wave trough antenna element which reacts in parallel with dissipative dielectric material contained within the wave trough, thereby furnishing a greater amount of attenuation and radiation protection.
  • Another object is to provide an environmental protective system for microwave ovens which is intrusion or tamperproof as far as the protective elements are concerned.
  • Another object is to provide a transmission circuit for the entrance of a microwave oven that is capable of absorbing excessively large amounts of microwave radiation.
  • Still another object is to provide additional attenuation of microwave energy escaping through the access opening of a microwave oven by serially or successively connecting together the individual wave troughs situated at the sides of the opening. More specifically, my invention recognizes that excessive leakage may occur at only one side of the oven's access door, and by feeding the radiated microwave power picked up by the particular wave trough at that side through the wave trough located where little or no leakage is taking place, a more effective attenuation is realized.
  • a dielectric material with a sufficient dielectric constant and loss factor is used to attenuate the flow of microwave power across and past a wave trough transmission line surrounding the periphery of an entrance to a microwave heating cavity, while simultaneously acting as a microwave phasing element for the integral microwave antenna circuit.
  • the dielectric material is placed within a metallic trough which acts as a reflector element in conjunction with a microwave detector propagation circuit which may be slightly embedded or covered with appropriate insulation.
  • the center conductor of the wave trough transmission line is orientated within thestructure in such a manner as to intercept microwave energy having multiple electric field of propagation.
  • FIG. 1 is a perspective view of a microwave oven having an exemplary form of my control and monitoring device installed thereon;
  • FIG. 2 is an enlarged fragmentary perspective view of the lower right hand comer of the oven illustrated in FIG. 1 for the purpose of showing to better advantage certain details not clearly set forth in FIG. 1;
  • FIG. 3 is a top plan view of a portion of one of the printed circuit boards depicted in FIGS. 1 and 2, the board carrying a cross-polarized radiation antenna that plays an important role in the practicing of my invention;
  • FIG. 4 is a schematic diagram showing a plurality of units comprising my radiation monitoring device which units are connected in series with alarm circuitry shown at one end for warning the user when an excessive amount of leakage occurs, the antenna array having a high frequency short at its other end;
  • FIG. 5 is a diagrammatic view corresponding to FIG. 4 but illustrating an additional termination at the end to which the warning circuitry is connected, the additional termination absorbing any excess power that may be radiated from the oven into my device;
  • FIG. 6 is still another diagram showing how my invention may be employed, the four units at the sides of the access opening being individually connected to an alarm circuit so as to signify more precisely where the fault exists, and
  • FIG. 7 is a sectional view taken in the direction of line 7-7 in FIGS. 1 and 2 but illustrating a somewhat modified oven construction which embodiment has been used during actual tests of my invention.
  • the oven 10 includes a cabinet 12 containing a cooking cavity 14 therein.
  • a microwave generator 16 appears at the rear and excites the cavity 14 through a wave guide 18.
  • the cabinet 12 has a front wall 20 with an access opening 22 therein.
  • a door 24 provides access to the cooking cavity 14 through the opening 22. More specifically, the door 24 includes an overlapping or overlying marginal portion or border 26, an offset panel portion 28 and a peripheral wall 30 that extends between the portions 26 and 28.
  • a hinge 31 permits the door 24 to be swung open in order to permit an article that is to be heated or cooked to be inserted through the opening 22 into the cavity 14.
  • the panel portion 28 is offset with respect to the overlapping or overlying marginal portion or border 26.
  • the panel portion 28 functions in cooperation with parts presently to be described to provide a primary radiation seal.
  • a spring seal 32 extends around the access opening 22 and that the offset panel portion 28 bears thereagainst when the door 24 is closed.
  • the access opening 22 is rectangular, there are sections of the seal 32 at each side of the opening 22. Accordingly, it is believed of assistance to assign specific distinguishing reference numerals to the portions of the spring seal 32 at each side of the access opening 22.
  • the spring seal at the bottom of the access opening 22 has been given the reference numeral 328, the portion at the right the numeral 32R, the portion at the top the numeral 32T and finally the portion at the left the reference numeral 32L.
  • the spring seal 32 composed of the portions 32B, 32R, 32T and 32L is reversely folded or bent to form a mounting strip 34 and a diverging resilient or flexible sealing strip 36. It is actually the strip 36, there being a strip associated with each portion 328, 32R, 32T and 32L, that is contacted or engaged by the door 24 when closed, more specifically the panel 28 thereof.
  • a stiffener 33 is interposed between the mounting strip 34 and the diverging strip 36. Any preferred number of mounting holes 38 (see FIG. 7) can be provided in the mounting strip 34, attaching screws 40 extending through these holes, through aligned holes in the stiffener 33 into tapped holes in the front wall 20 of the cabinet 12; one such screw 40 can be seen in FIG. 2.
  • the primary radiation seal that involves the door 24, more specifically the panel portion 28 thereof, and the spring seal 32 is not per se novel.
  • the difficulty experienced with such a seal has entailed certain drawbacks and the present invention seeks to obviate the shortcomings of such an arrangement standing alone.
  • the spring contact method has resulted in leakage where the spring parts are not kept clean, thereby permitting an objectionable amount of radiation leakage to take place.
  • arcing has taken place with a concomitant deterioration of the seal itself.
  • the sealing construction described above which is only typical of several primary radiation seals
  • the radiation device 42 is composed of four individual units that may be arrayed in two different ways, as will become apparent as the description progresses.
  • the individual units constituting the radiation device 42 have been labeled 42B, 42R, 42T and 42L (all four units appearing in FIG. 4, as well as in FIGS. and 6), the letter designations corresponding to those employed in conjunction with the spring seal 32.
  • Each unit 42B, 42R, 42T and 42L includes a channelshaped trough member 44 having spaced side walls 46, 48 and a connecting wall 50.
  • the trough member 44 thus forms a longitudinal recess or groove 52 having an entrance slot 54 lying in the plane of the edges of the side walls 46, 48.
  • the foregoing construction is pictorially represented in FIG. 2 and reference thereto will provide a ready understanding of the detailsinvolved.
  • any preferred number of screws 56 passing through a corresponding number of holes 58 in the front wall 20 serve to anchor the radiation device 42 in place, the screws 56 being threadedly engaged with holes 60 in the side wall 46 of each trough member 44.
  • the radiation device 42 can be succinctly described as resembling a rectangular picture frame, the trough members 44 constituting the molding thereof.
  • the trough member 44 is of metal, preferably extruded aluminum, but the material contained therein, which has been indicated by the reference numeral 62, is a dielectric material.
  • Various synthetic resins may be used as the dielectric material 62.
  • a number of synthetic resins are satisfactory, such as epoxy (Araldite), urea, phenolic, polyester or if desired a ceramic material may be employed.
  • the specific type of dielectric material utilized during the testing procedures will be described hereinafter when referring to other data concerned with the actual testing of my radiation device 42.
  • the printed circuit vboard 64 includes a plastic substrate or base strip 65, such as fiber glass epoxy, and has evaporated thereon or otherwise applied thereto a copper antenna 66 in the form of a flat ribbon.
  • the antenna 66 is a cross-polarized antenna, the specific configuration or pattern thereof is important and in this regard it will be discerned from FIG.
  • the antenna 66 is composed of spaced longitudinal portions 660 residing near the access opening 22 and alternately spaced portions 66b spaced farther from the access opening 22 there being transverse portions 660 connecting the various portions 66a and 66b together so as to provide a continuous transmission line.
  • the actual dimensions of the antenna 66 will be given when describing the specific test embodiment. At this time, though, it should be recognized that the antenna 66 resides in a plane perpendicular to the plane of the access opening 22. The plane of the antenna 66 also is perpendicular to the general plane of the door 24 when closed. It will be appreciated that the overlapping or overlying marginal portion or border 26 of the door 24 confronts the side wall 48 of each trough member 44 when the door 24 is closed.
  • the side wall 48 that is the face thereof toward the overlying portion 26, is coated with a suitable gasket type of material (not shown), which may be an epoxy resin.
  • gasket material on the side wall 48 is not necessary to the invention nor is it a novel idea. For instance, it could very well be added for more attenuation or prevention of intrusionary objects into the mentioned gap.
  • a somewhat similar covering or coating should be applied thereover; this coating has not been shown in the drawings but it should be a protective covering material that does not interfere with transmission circuits.
  • the antenna 66 changes planes at the four comers of the access opening 22'.
  • One such corner in both FIGS. 1 and 2 has been indicated by the reference numeral 68 and this same comer appears in the several schematic diagrams set forth in FIGS. 4-6.
  • a different mode of connection is resorted to in FIGS. 4 and 5 than appearing in FIG. 6.
  • the radiation device 42 is composed of individual units 42B, 42R, 42T and 42L.
  • the various antennas 66 are connected at three of the corners 68 so as to provide a series-connected antenna array.
  • the configuration or pattern shown in FIG. 4 results in a relatively long antenna composed of the various individual antennas 66 and to simplify the ensuing description one end of the antenna array has been given the reference numeral 70 and the opposite end thereof the reference numeral 72.
  • the end 70 is terminated by a capacitor 74 having one side or plate thereof connected to the end 70 and the other side or plate connected to the trough member 44 at 76.
  • the various trough members 44 are grounded at 78.
  • the capacitor 74 provides a low impedance, actually a short circuit as far as microwave frequencies are concerned, to the metallic trough member 44.
  • the capacitor 74 provides an isolated or open circuit as far as direct current is concerned.
  • the detection means for monitoring or sensing the amount of microwave energy picked up by the radiation device 42 will now be described. Accordingly, the other end 72 of the antenna array appearing in FIG. 4 is connected to the cathode of a diode 82, the anode thereof being connected to the trough 44 at 84. Also connected to the end 72 of the antenna array appearing in FIG. 4 is a high reactance microwave inductance labeled 86.
  • the inductance 86 is connected to a signaling circuit denoted in its entirety by the reference numeral 88.
  • the circuit 88 includes a potentiometer 90, the wiper arm thereof being connected to the inductance 86.
  • the potentiometer 90 is in circuit with the gate of a silicon controlled switch 92, such as a General Electric type 3N58 series, the gate being identified by the numeral 94. It will be perceived from FIG. 4 that the anode of the switch 92 is connected to a relay coil labeled 96 having normally open contacts 98. In circuit with the normally open contacts 98 is a warning lamp 100 that is supplied from a source of power, such as the battery 102. Hence, when the relay coil 96 is energized, the contacts 98 close so as to energize the lamp 100, thereby providing the warning that an excessive amount of radiation is taking place.
  • a source of power such as the battery 102.
  • FIG. 5 in the monitoring or sensing of the microwave energy the end 70 of the serially connected antenna array is connected in the same fashion as in FIG. 4, and therefore the capacitor 74 appears again in this figure. Likewise, the end 72 is connected through the same diode 82 to the trough member 44.
  • the circuitry of FIG. 5 differs from that constituting FIG. 4 by virtue of an additional termination assigned the reference numeral 104.
  • the additional termination 104 is in the form of an absorbing medium such as ferrite or graphite material, the additional termination being grounded at 105. In the embodiment of FIG. 5, the additional termination 104 assures the absorption of excessive amounts of power delivered to any of the antennas 66.
  • each circuit 88 has its own warning lamp 100.
  • the various circuits 88 have been distinguished from each other by the letter suffix that has been used heretofore. Consequently, the circuit 88 for the bottom side of the access opening 22 has been assigned the reference numeral 888, the circuit for the right side 88R, the circuit for the top the numeral 88T and the circuit for the left side the numeral 88L.
  • any leakage escaping between the door 24 and the spring seal 32 is directed to the radiation device 42.
  • the trough members 44 being metallic, reflect any leaking energy not first intercepted by the antenna 66. Owing to the somewhat lossy nature of the dielectric material 62, some of the microwave power is attenuated as it is reflected by the interior of the trough members 44. Due to the orientation of the antenna 66, being cross-polarized, the microwave energy that escapes past the primary seal is not only intercepted but is propagated along the antenna in a transmission line fashion.
  • the attenuation causes the attenuation to be accentuated, for whether the escape route is at the bottom, sides or top of the access opening 22, the energy is picked up and the entire device 42 serves to dissipate the energy picked up by the wave trough-type transmission line constituting the radiation device 42.
  • This is true of either transverse electric or transverse magnetic waves, and the energy or power not dissipated is propagated through the entire antenna array to the capacitor 74.
  • the capacitor 74 serves as a virtual short circuit for any energy reaching the end 70 of the antenna array depicted in FIG. 4.
  • a triggering signal is applied to the gate 94 of the silicon controlled switch 92 which results in the energizing of the relay coil 76 and the simultaneous closing of the normally open contact 98. This causes the warning lamp to be illuminated and the user is thereby apprised that the oven 10 is not functioning properly.
  • the contacts 98 can also be used to disable the microwave generator 16 so as to completely inactivate the oven 10 and prevent further use thereof until the leakage situation has been corrected.
  • the load referred to as the additional termination 104 will be effective in absorbing any microwave power that would not be dissipated when utilizing the circuit arrangement of FIG. 4. Otherwise, the embodiment of FIG. 5 functions in the same manner as the embodiment of FIG. 4.
  • each radiation unit 42B, 42R, 42T and 42L is responsible for dissipating any leakage radiation that is received by the particular unit.
  • the distinct advantage when utilizing the teachings of FIG. 6 is that the particular lamp 100, that is the lamp 100 associated with the circuit 88B, 88R, 88T or 88L, localizes the fault and advises the user of the particular location so that the fault in the primary sealing arrangement can be promptly corrected.
  • the oven includes a cabinet 112 containing a cooking cavity 114.
  • a front wall provides the access opening 122.
  • the door identified by the numeral 124 in FIG. 7 differs somewhat from the door 24.
  • the door 124 includes a'marginal portion or border 126, an offset panel portion 128 and a peripheral connecting wall 130.
  • this device With respect to the radiation device 42, this device as shown in FIG. 7 corresponds closely to what has been illustrated in FIGS. 1 and 2. it will perhaps be well, though, to list the dimensions of the trough member 44.
  • the dielectric material 62 As far as the dielectric material 62 is concerned, the actual material used possessed a dielectric constant of 11.2 and a dielectric loss tangent of 0.04 as measured by the Massachusetts Institute of Technology when subjected to a frequency of 3,000 mHz.
  • the material was a polyester resin marketed by Ashland Chemical Company, a division of Ashland Oil & Refining Company, and modifications of this material are aptly described in their technical bulletin l 148 of June 1968. Such materials are highly desirable in that they contain moisture on the order of 50 percent on a weight basis.
  • the antenna 66 For an operating frequency of 2,450 i- 20 ml-lz., the antenna 66, which is detailed in FIG. 3, had the following dimensions:
  • e in the above listing is the width of the printed circuit board 64. Missing from the above tabulation is the thickness of the copper circuitry constituting the antenna 66; in practice it was 0.0028 inch. The thickness of the substrate 65 was 0.023 inch.
  • the silicon controlled switch 92 has already been identified as a General Electric type 3N58. However, the diode 82 has not been identified.
  • This diode constituted a Hewlett-Packard series 5082 rectifier of the epitaxial, planar, passivated diode type whose construction utilizes a combination of both a conventional PN junction and a Schottby barrier.
  • This rectifier quite desirably, has the high breakdown and temperature characteristics of silicon, the turn on voltage of germanium, and the speed of a Schottby barrier, majority carrier device.
  • the dimensions of this cavity were 30 cm. (depth) by 39 cm. (width) by 24 cm. (height).
  • the cavity power supplied by the generator 16 was 700 watts.
  • the frequency, as indicated above, was 2,450 i 20 mHz.
  • Microwave heating apparatus in accordance with claim 1 in which said radiation device is disposed at a location between said wall and a confronting portion of said door.
  • Microwave heating apparatus in accordance with claim 2 in which said radiation device includes a dielectric material contained in said recess for supporting said antenna means.
  • Microwave heating apparatus in accordance with claim 3 in which said antenna means constitutes an element having a first series of spaced portions thereof located nearer said cavity, and a second series of alternate spaced portions thereof located nearer said door and a third series of connecting portions extending between said first and second portions.
  • Microwave heating apparatus in accordance with claim 5 in which said antenna element is in the form of a flat ribbon residing in a plane perpendicular to the plane of the access opening.
  • Microwave heating apparatus in accordance with claim 4 in which said radiation device includes termination means at one end thereof providing a relatively low impedance path between said antenna means and said trough means.
  • Microwave heating apparatus in accordance with claim 7 in which said termination means includes a capacitor for shorting high frequency power from said antenna means to said trough means.
  • Microwave heating apparatus in accordance with claim 7 including detection means connected to the other end of said radiation device for monitoring the amount of microwave energy picked up by said radiation device.
  • Microwave heating apparatus in accordance with claim 9 in which said detection means includes a control switch and means for rectifying a portion of the microwave power picked up by said radiation device to supply direct current to said control switch and cause operation thereof when the direct current supplied thereto reaches a predetermined level.
  • Microwave heating apparatus in accordance with claim 8 in which said radiation device includes a plurality of antenna elements connected in series and said capacitor is connected at one end of said serially connected antenna elements.
  • Microwave heating apparatus in accordance with claim 1 1 including an additional termination means at the other end of said serially connected antenna elements, said additional termination means being capable of absorbing excessive amounts of power delivered to said plurality of antenna elements.
  • Microwave heating apparatus comprising a cabinet having a cooking cavity therein and an access opening in one wall thereof through which an article to be heated is inserted, a
  • Microwave heating apparatus in accordance with claim 13 in which said trough members are joined to form a serially connected trough configuration extending along the sides of said access opening and in which said individual antenna elements are also serially connected to form a unitized construction, and means connected between one end of the thus formed antenna array and one of said interconnected trough members for dissipating at least some of the microwave power radiated to said antenna array which power has leaked past said primary sealing means.
  • Microwave heating apparatus in accordance with claim 14 including means connected to the antenna array for sensing the amount of microwave power radiated to said antenna array.
  • Microwave heating apparatus in accordance with claim 15 in which said sensing means is connected to the other end of said antenna array.
  • Microwave heating apparatus in accordance with claim 15 including means connected to said antenna array for absorbing excessive amounts of power radiated to said antenna array.
  • Microwave heating apparatus in accordance with claim 17 in which said absorbing means is connected to the other end of said antenna array.
  • Microwave heating apparatus in accordance with claim 19 including respective means connected to the other end of said antenna elements for sensing the amount of microwave power radiated to each antenna element.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Electric Ovens (AREA)
US109303A 1971-01-25 1971-01-25 Microwave heating apparatus with radiation control and monitoring Expired - Lifetime US3651300A (en)

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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2321227A1 (fr) * 1975-03-31 1977-03-11 Amana Refrigeration Inc Joint de porte de four a hyperfrequences
US4041266A (en) * 1972-10-25 1977-08-09 Chemetron Corporation Sensor and tray arrangement
US4115680A (en) * 1975-05-05 1978-09-19 Chemetron Corporation Apparatus for providing temperature equalization cycles for a microwave oven
FR2410224A1 (fr) * 1977-11-25 1979-06-22 Raytheon Co Four a hyperfrequences avec dispositif d'arret
FR2465392A1 (fr) * 1979-09-11 1981-03-20 Bosch Siemens Hausgeraete Appareil de chauffage a micro-ondes muni d'un dispositif d'etancheite pour micro-ondes
US4313044A (en) * 1980-11-05 1982-01-26 General Electric Company Slot configuration for choke seal
FR2508756A1 (fr) * 1981-06-30 1982-12-31 Rca Corp Dispositif de blindage haute-frequence sans contact
US4414425A (en) * 1981-09-28 1983-11-08 Rca Corporation Broadband non-contacting RF shielding gasket
US4523069A (en) * 1983-10-24 1985-06-11 General Electric Company Microwave oven door seal
FR2599127A1 (fr) * 1986-05-23 1987-11-27 Labo Electronique Physique Four a micro-ondes comportant un dispositif de securite de fermeture de porte
EP0287549A1 (de) * 1987-04-14 1988-10-19 Helmut Dr. Katschnig Vorrichtung zum Erhitzen von Gegenständen und Organismen
US5824999A (en) * 1996-02-23 1998-10-20 Samsung Electronics Co., Ltd. Microwave leakage-preventing device for a microwave oven
US5861612A (en) * 1996-04-24 1999-01-19 Lg Electronics, Inc. Multimode electromagnetic wave energy rejection filter arrangement for a slot waveguide
CN100365344C (zh) * 2006-02-28 2008-01-30 王宝根 带微波吸收腔的新型微波炉
CN102484911A (zh) * 2009-08-20 2012-05-30 松下电器产业株式会社 电磁波加热装置
US20210352781A1 (en) * 2020-05-11 2021-11-11 Lg Electronics Inc. Oven having multiple chokes
US11777190B2 (en) * 2015-12-29 2023-10-03 Whirlpool Corporation Appliance including an antenna using a portion of appliance as a ground plane

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DE102004052798B4 (de) * 2004-11-02 2006-08-31 Electrolux Home Products Corp. N.V. Garofen
RU2661422C1 (ru) * 2017-06-20 2018-07-16 Федеральное государственное автономное образовательное учреждение высшего образования "Северный (Арктический) федеральный университет имени М.В. Ломоносова" СВЧ лесосушильная камера

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US2958754A (en) * 1958-12-15 1960-11-01 Gen Electric Electronic ovens
US3511959A (en) * 1968-02-16 1970-05-12 Varian Associates Microwave cavity having a varied impedance transmission line microwave energy seal around the access door opening
US3525841A (en) * 1968-11-04 1970-08-25 Litton Precision Prod Inc Door seal for microwave ovens

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Publication number Priority date Publication date Assignee Title
US2958754A (en) * 1958-12-15 1960-11-01 Gen Electric Electronic ovens
US3511959A (en) * 1968-02-16 1970-05-12 Varian Associates Microwave cavity having a varied impedance transmission line microwave energy seal around the access door opening
US3525841A (en) * 1968-11-04 1970-08-25 Litton Precision Prod Inc Door seal for microwave ovens

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041266A (en) * 1972-10-25 1977-08-09 Chemetron Corporation Sensor and tray arrangement
FR2321227A1 (fr) * 1975-03-31 1977-03-11 Amana Refrigeration Inc Joint de porte de four a hyperfrequences
US4115680A (en) * 1975-05-05 1978-09-19 Chemetron Corporation Apparatus for providing temperature equalization cycles for a microwave oven
FR2410224A1 (fr) * 1977-11-25 1979-06-22 Raytheon Co Four a hyperfrequences avec dispositif d'arret
FR2465392A1 (fr) * 1979-09-11 1981-03-20 Bosch Siemens Hausgeraete Appareil de chauffage a micro-ondes muni d'un dispositif d'etancheite pour micro-ondes
US4347420A (en) * 1979-09-11 1982-08-31 Matsushita Electric Industrial Co., Ltd. Microwave seal structure in microwave oven
US4313044A (en) * 1980-11-05 1982-01-26 General Electric Company Slot configuration for choke seal
FR2508756A1 (fr) * 1981-06-30 1982-12-31 Rca Corp Dispositif de blindage haute-frequence sans contact
US4414425A (en) * 1981-09-28 1983-11-08 Rca Corporation Broadband non-contacting RF shielding gasket
US4523069A (en) * 1983-10-24 1985-06-11 General Electric Company Microwave oven door seal
FR2599127A1 (fr) * 1986-05-23 1987-11-27 Labo Electronique Physique Four a micro-ondes comportant un dispositif de securite de fermeture de porte
EP0247668A1 (fr) * 1986-05-23 1987-12-02 Laboratoires D'electronique Philips Four à micro-ondes comportant un dispositif de sécurité de fermeture de porte
EP0287549A1 (de) * 1987-04-14 1988-10-19 Helmut Dr. Katschnig Vorrichtung zum Erhitzen von Gegenständen und Organismen
US5098665A (en) * 1987-04-14 1992-03-24 Helmut Katschnig Device for heating of articles and organisms
US5824999A (en) * 1996-02-23 1998-10-20 Samsung Electronics Co., Ltd. Microwave leakage-preventing device for a microwave oven
US5861612A (en) * 1996-04-24 1999-01-19 Lg Electronics, Inc. Multimode electromagnetic wave energy rejection filter arrangement for a slot waveguide
CN100365344C (zh) * 2006-02-28 2008-01-30 王宝根 带微波吸收腔的新型微波炉
CN102484911A (zh) * 2009-08-20 2012-05-30 松下电器产业株式会社 电磁波加热装置
US20120138600A1 (en) * 2009-08-20 2012-06-07 Panasonic Corporation Electromagnetic wave heating device
US11777190B2 (en) * 2015-12-29 2023-10-03 Whirlpool Corporation Appliance including an antenna using a portion of appliance as a ground plane
US20210352781A1 (en) * 2020-05-11 2021-11-11 Lg Electronics Inc. Oven having multiple chokes
US12171052B2 (en) * 2020-05-11 2024-12-17 Lg Electronics Inc. Oven having multiple chokes

Also Published As

Publication number Publication date
FR2124646A5 (enExample) 1972-09-22
DE2160958C3 (de) 1975-03-27
NL7117393A (enExample) 1972-07-27
JPS5148576B1 (enExample) 1976-12-21
NL162286B (nl) 1979-11-15
DE2160958B2 (de) 1974-08-08
NL162286C (nl) 1980-04-15
DE2160958A1 (de) 1972-08-03
GB1322857A (en) 1973-07-11

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