US3810248A - Microwave heating apparatus - Google Patents

Microwave heating apparatus Download PDF

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Publication number
US3810248A
US3810248A US00188015A US18801571A US3810248A US 3810248 A US3810248 A US 3810248A US 00188015 A US00188015 A US 00188015A US 18801571 A US18801571 A US 18801571A US 3810248 A US3810248 A US 3810248A
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United States
Prior art keywords
section
microwave
branch
wave guide
width
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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
US00188015A
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English (en)
Inventor
Per Olov Risman
Lars Rosengren
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Husqvarna Vapenfabriks AB
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Husqvarna Vapenfabriks AB
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Application filed by Husqvarna Vapenfabriks AB filed Critical Husqvarna Vapenfabriks AB
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Publication of US3810248A publication Critical patent/US3810248A/en
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Expired - Lifetime legal-status Critical Current

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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
    • H05B6/80—Apparatus for specific applications
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/70—Feed lines
    • H05B6/707—Feed lines using waveguides
    • H05B6/708—Feed lines using waveguides in particular slotted waveguides

Definitions

  • a microwave heating apparatus is disclosed, the apparatus being provided with a treatment chamber, a microwave source, and a wave guide having a mode converter.
  • a first section of the wave guide connected to the treatment chamber is joined to a second section connected to the microwave source and has a rectangular cross-sectional area with sides approximately equal to a and b under formation of a so-called H- bend, the first section having a cross-sectional area in the form of a rectangle with sides approximately equal to n X a and b, where n 2, 3, 4, etc., and wherein the l-l-bend between two outer sides of the respective wave guide sections have a corner-plate parallel to the rectangle sideb of'the wave guide cross-section areas and form inside obtuse angles with the outer side.
  • the apparatus ensures spreading and distribution of the radiation in the treatment chamber with an even intensity.
  • the present invention relates to a microwave heating apparatus in which microwave energy is conducted from a microwave source to a microwave heating applicator by means of a waveguide, provided with a mode converter.
  • a converter specially designed for the purpose is used, which is very simple and effective. Its principal characteristics for fulfilling the function which leadto the improvement of the microwave oven are defined in such a way that a first section of a wave guide connected to the treatment chamber is joined to a second section connected to the microwave source and having a rectangular cross-section with sides approximativelya and b, under formation of a so-called H-bend, said first section having a crosss'ection in the form of a rectangle with sidesa'pproximatively n a and b where n 2, 3, 4cm, and that said I-I-bend between two outer sides of the respective waveguide sections has a corner-plate parallel to the rectangle side b of the waveguide cross-sections and forming inside obtuse angles with the outer sides.
  • FIG. 1 is a perspective view showing such an appliance in a combination oven-hotplate or surface unit
  • FIG. 2 is a detailed view of a waveguide switch used in the appliance according to FIG. 1,
  • FIG. 3 is a cross-section of a vessel with a base, constituting an absorber, intended to be used on a cooking plate according to FIG. 1,
  • FIG. 4 shows in a horizontal projection a waveguide with a mode-converter and FIG. 5 shows a vertical projection of the waveguide.
  • the oven has atight-closing door 3 on the frontside and is suitable for being placed on a kitchen range or for being built into a cupboard.
  • the cookingplate is fixedto one side of the oven and has a panel equipped with control knobs 4 and indicator lamps 5.
  • the plate and the oven each form the base for a microwave applicator or radiation surface 6 and re spectively.
  • a waveguide system conducts the radiation from a magnetron 8 to the respective applicator.
  • the magnetron has an aerial 9 which is located in the end of a main waveguide 10 which is provided with a waveguide switch 11 from which issues a branch waveguide 12.
  • the waveguide switch which is shown :in FIG. 2,
  • the two waveguides are each by itself provided with mode converters.
  • Such a converter consists for example of a waveguide with a waveguide passage in form of a corner, for example as formed by the main waveguide 10 and a waveguide tube 15 at an angle to the same.
  • the 1 is designed as a TE -waveguide and conducts the TE waves emitted by the magnetron to the waveguide corner.
  • This comprises the connection of the tube 15 at an angle with the main guide 10 as well as a corner plate 16 between two outer sides 17, 18 of the respective tubes.
  • the cross-section of the tube 15 defines a rectangle with a long side of approximatelydouble the length of the corobtuse angle'therewith.
  • the plate reflects the TB waves incident from the main guide into the tube with simultaneous conversion of a part of the TE waves to TE waves.
  • the combined radiation of TE and 'TE type which is obtained in the normal manner by squaring and halving of the amplitude values, is thus sectional area in different parts, than is the case in a pure TE Waveguide.
  • the converter shown in FIG. 4 constitutes a simple example of how a wave type can be converted, while the principle also comprises multiple and complex con- .vers'ions of thistyp'e. lf, for example, several of the waveguide passages now described arecoupled behind one another, or if a specially wide tube replaces the tube 15, it can be stated in advance that the radiation issuing will include wave shapes TE TE TE wherein, however, certain terms may dominate while others will be wholly excluded. 7
  • the construction of the converter shown is very simple to realize, since the sides of the waveguides are made up of edge-flanged sheetsand even the corner plate 16 can be made of such sheet, which means that the converter is built only of elements generally used for waveguides. It is also possible to arrange in the waveguide tube a control element for the propagation of the waves; thus two parallel slots 15a are present in the tube 15 on both sides about the central plane. In these slots which are in the proximity of the amplitudes of the TE' -wave so-calledchokes could be arranged,
  • the tube 15 has on the topside the radiation surface 6 surrounded by a ring or frame 19 and provided with a number of slots 20 in the wall of the tube. As the end ,of tube 21 is closed by a plate 22, the microwave radiation issues through the slots. On top of the radiation surface, suitably fixed on the ring, is placed the load,
  • the pot is made of metal and is provided with a lid and a handle as well with a collar 23 in the lower portion which fits against the ring 19 when the pot is placed on the radiation surface. Through this the radiation is screened effectively from the surroundings.
  • the base in the pot has two layers, a metal layer 24 and an absorption layer 25.-The metal layer may be very thin and serves on the one hand as a radiation protection in the pot and on the other hand as a roasting surface for the object in the pot.
  • the absorption layer is formed by an active material, for example Fe O or NiFe O coal or a similar material, together with a binder and is placed directly on the metal layer.
  • the two layers are therefore thermally very well attached and the energy taken up in the absorption layer is conducted with very small losses to the metal layer.
  • the two layers have a low heat capacity and therefore heat up quickly when the absorber is exposed to radiation.
  • the base of the vessel will cool down with appreciable delay when the radiation stops.
  • the waveguide 12 present in the bottom of the oven together with mode converters is realized in principle similarly to those just described, except that a waveguide section 26 with a width approximately three times the width of the branch waveguide 12 is used.
  • a portion of the TE wave will here be converted to both TE and TE waves.
  • the radiation surface 7 on this waveguide section can be made larger than the corresponding surface on the waveguide tube 15.
  • the surface 7 is surrounded by a ring 27 and in this is fitted a round absorption plate similar to the one which forms the base of the pot according to FIG. 3. As the oven forms a closed space, no extra radiation protection is required, so that the metal layer on the absorption layer can be excluded on this absorption plate.
  • the effect alluded to in the introduction is achieved, namely that an article on the plate is warmed up partly through contact pressure on the plate and, partly through microwave radiation which passes through the plate and has an effect on the article.
  • the absorption capacity of the plate for example with the help of the thickness, it is possible to alter the ratio of transmitted to absorbed radiation effect.
  • a dish can thus be roasted on the surface by the heat which has been absorbed and is given off by the plate, at the same time as the microwave radiation warms the dish homogeneously right through. In this way a considerable amount of time is saved in the preparation without the dish being deprived of the desirable browned surface.
  • Such a preparation which comprises both roasting and microwave heating may also be carried out in a pot such as that shown in FIG. 3, in which, however, the radiation-protecting metal layer 24 has been excluded.
  • the principle of roasting and heating at the same time is in a wider sense also applicable to baking.
  • the baking molds may, for example, be provided with an absorbing layer, which brings about that the mold remains warm so that a crust is formed on its contents, at the same time as a part of the radiation penetrates into the side of the molds and rapid-bakes" the contents.
  • a combination of oven and cooking plate according to the embodiment shown has the advantage that the scope of application for microwave heating is widened. Furthermore, the expensiveelectronic equipment can be used jointly for oven and plate; It is not to be regarded as essential, however, for the realization of the invention that this combination exists; a microwave heating appliance with an absorber may comprise only a cooking plate, only an oven, or either built into a conventional cooker.
  • a microwave heating apparatus'including treatment means a microwave source connected to a wave guide having a mode converter, said wave guide being provided with first and second sections, said first section having a width ofa and a height of b, said second section having a width equal to n'a' in which n 2,3,4, etc. and a height equal to b, said first section being connected to the microwave source, said second section being connected to said treatment means, said first section being joined to said second section by an- H-bend forming inside obtuse angles between the outer b sides of said first and second sections.
  • the apparatus as claimed in claim 4 further including vessel means including a plate means having a high coefficient of microwave absorption converting microwave energy to thermal energy, and an external holder detachably fitting the vessel means.
  • the apparatus as claimed in claim 1 further including a branch section connected to said first section to extend at right angles thereto, said branch section having a width of a and a height of b, said branch section being connected to a further-section having a width approximately three times the width of the branch section, and a height of b, said further section being joined to said branch section by an l-l-bend forming inside obtuse angles between the outer b sides of said branch and said further section, and a switching means at the connection between the branch section and first section movable between a position oblique to the first section and a position parallel with the first section for directing radiation from said microwave source into the branch section and into the first section respectively.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Cookers (AREA)
  • Electric Ovens (AREA)
  • Package Specialized In Special Use (AREA)
US00188015A 1970-10-19 1971-10-12 Microwave heating apparatus Expired - Lifetime US3810248A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE14061/70A SE343742B (de) 1970-10-19 1970-10-19

Publications (1)

Publication Number Publication Date
US3810248A true US3810248A (en) 1974-05-07

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ID=20298457

Family Applications (1)

Application Number Title Priority Date Filing Date
US00188015A Expired - Lifetime US3810248A (en) 1970-10-19 1971-10-12 Microwave heating apparatus

Country Status (11)

Country Link
US (1) US3810248A (de)
AU (1) AU466306B2 (de)
BE (1) BE774075A (de)
CH (1) CH564300A5 (de)
DD (1) DD94864A5 (de)
DE (1) DE2166290C3 (de)
DK (1) DK136050B (de)
GB (1) GB1364734A (de)
NL (1) NL7114369A (de)
NO (1) NO134027C (de)
SE (1) SE343742B (de)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4019009A (en) * 1974-02-08 1977-04-19 Matsushita Electric Industrial Co., Ltd. Microwave heating apparatus
US4121078A (en) * 1975-04-30 1978-10-17 Matsushita Electric Industrial Co., Ltd. Microwave heating apparatus
US4198555A (en) * 1978-01-09 1980-04-15 De Pruines Iseco S. A. Cabinet for storing prepared meals on individual trays
EP0037643A1 (de) * 1980-03-26 1981-10-14 THORN EMI Domestic Appliances Limited Mikrowellenkochherde
US4329557A (en) * 1979-12-07 1982-05-11 General Electric Company Microwave oven with improved energy distribution
US4354083A (en) * 1980-11-05 1982-10-12 General Electric Company Microwave oven with novel energy distribution arrangement
DE3310703A1 (de) * 1982-03-30 1983-10-13 General Electric Co., Schenectady, N.Y. Mikrowellenkochgeraet
US4463239A (en) * 1982-12-06 1984-07-31 General Electric Company Rotating slot antenna arrangement for microwave oven
US4464554A (en) * 1982-08-25 1984-08-07 General Electric Company Dynamic bottom feed for microwave ovens
US4695693A (en) * 1986-10-02 1987-09-22 General Electric Company Triangular antenna array for microwave oven
US5166487A (en) * 1989-12-15 1992-11-24 Tecogen, Inc. Cooking oven with convection and microwave heating
FR2689220A1 (fr) * 1992-03-24 1993-10-01 Desmet Frederic Refrigérateur à absorption utilisant les micro-ondes comme mode de chauffage et associé à d'autres systèmes de chauffage micro-ondes.
US5451751A (en) * 1992-01-23 1995-09-19 Kabushiki Kaisha Toshiba High-frequency heating apparatus with wave guide switching means and selective power switching means for magnetron
US5874715A (en) * 1996-07-31 1999-02-23 Lg Electronics Inc. Heating apparatus in the form of an antenna array plate for a microwave oven
US5874706A (en) * 1996-09-26 1999-02-23 Tokyo Electron Limited Microwave plasma processing apparatus using a hybrid microwave having two different modes of oscillation or branched microwaves forming a concentric electric field
US5990466A (en) * 1998-04-02 1999-11-23 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US6008483A (en) * 1998-10-09 1999-12-28 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
WO2003040630A2 (en) * 2001-11-09 2003-05-15 Personal Chemistry I Uppsala Ab Microwave applicator system
US6607920B2 (en) 2001-01-31 2003-08-19 Cem Corporation Attenuator system for microwave-assisted chemical synthesis
US6649889B2 (en) 2001-01-31 2003-11-18 Cem Corporation Microwave-assisted chemical synthesis instrument with fixed tuning
US20040101441A1 (en) * 2002-11-26 2004-05-27 Cem Corporation Pressure measurement and relief for microwave-assisted chemical reactions
US20040221654A1 (en) * 2001-01-31 2004-11-11 Jennings William Edward Pressure measurement in microwave-assisted chemical synthesis
US6960747B2 (en) * 2001-11-09 2005-11-01 Personal Chemistry I Uppsala Ab Microwave applicator system
US7092988B1 (en) 1997-05-27 2006-08-15 Jeffrey Bogatin Rapid cooking oven with broadband communication capability to increase ease of use
US8224892B2 (en) 2000-04-28 2012-07-17 Turbochef Technologies, Inc. Rapid cooking oven with broadband communication capability to increase ease of use
US9282594B2 (en) 2010-12-23 2016-03-08 Eastman Chemical Company Wood heater with enhanced microwave launching system
US20160219653A1 (en) * 2015-01-27 2016-07-28 Samsung Electronics Co., Ltd. Cooking Apparatus and Controlling Method Thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE387815B (sv) * 1974-12-18 1976-09-13 Husqvarna Ab Mikrovagsapplikator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2576862A (en) * 1946-06-11 1951-11-27 Electronic Chemical Engineerin Method and apparatus for preserving foodstuffs
US2600566A (en) * 1949-11-23 1952-06-17 Jr Frank Wesley Moffett Method of heating frozen food packages
US2673962A (en) * 1949-01-18 1954-03-30 Bell Telephone Labor Inc Mode suppression in curved waveguide bends
US2814708A (en) * 1952-01-05 1957-11-26 Raytheon Mfg Co Microwave ovens
US2909635A (en) * 1957-07-29 1959-10-20 Raytheon Co Electronic oven systems
US3539751A (en) * 1966-10-26 1970-11-10 Melvin L Levinson Insulating implement for use in a microwave oven
US3662141A (en) * 1968-06-06 1972-05-09 Gen Motors Corp Oven shelf adapted to absorb microwave energy and conduct heat to a load

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2576862A (en) * 1946-06-11 1951-11-27 Electronic Chemical Engineerin Method and apparatus for preserving foodstuffs
US2673962A (en) * 1949-01-18 1954-03-30 Bell Telephone Labor Inc Mode suppression in curved waveguide bends
US2600566A (en) * 1949-11-23 1952-06-17 Jr Frank Wesley Moffett Method of heating frozen food packages
US2814708A (en) * 1952-01-05 1957-11-26 Raytheon Mfg Co Microwave ovens
US2909635A (en) * 1957-07-29 1959-10-20 Raytheon Co Electronic oven systems
US3539751A (en) * 1966-10-26 1970-11-10 Melvin L Levinson Insulating implement for use in a microwave oven
US3662141A (en) * 1968-06-06 1972-05-09 Gen Motors Corp Oven shelf adapted to absorb microwave energy and conduct heat to a load

Cited By (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4019009A (en) * 1974-02-08 1977-04-19 Matsushita Electric Industrial Co., Ltd. Microwave heating apparatus
US4121078A (en) * 1975-04-30 1978-10-17 Matsushita Electric Industrial Co., Ltd. Microwave heating apparatus
US4198555A (en) * 1978-01-09 1980-04-15 De Pruines Iseco S. A. Cabinet for storing prepared meals on individual trays
US4329557A (en) * 1979-12-07 1982-05-11 General Electric Company Microwave oven with improved energy distribution
EP0037643A1 (de) * 1980-03-26 1981-10-14 THORN EMI Domestic Appliances Limited Mikrowellenkochherde
US4354083A (en) * 1980-11-05 1982-10-12 General Electric Company Microwave oven with novel energy distribution arrangement
DE3310703A1 (de) * 1982-03-30 1983-10-13 General Electric Co., Schenectady, N.Y. Mikrowellenkochgeraet
US4458126A (en) * 1982-03-30 1984-07-03 General Electric Company Microwave oven with dual feed excitation system
US4464554A (en) * 1982-08-25 1984-08-07 General Electric Company Dynamic bottom feed for microwave ovens
US4463239A (en) * 1982-12-06 1984-07-31 General Electric Company Rotating slot antenna arrangement for microwave oven
US4695693A (en) * 1986-10-02 1987-09-22 General Electric Company Triangular antenna array for microwave oven
US5166487A (en) * 1989-12-15 1992-11-24 Tecogen, Inc. Cooking oven with convection and microwave heating
US5451751A (en) * 1992-01-23 1995-09-19 Kabushiki Kaisha Toshiba High-frequency heating apparatus with wave guide switching means and selective power switching means for magnetron
FR2689220A1 (fr) * 1992-03-24 1993-10-01 Desmet Frederic Refrigérateur à absorption utilisant les micro-ondes comme mode de chauffage et associé à d'autres systèmes de chauffage micro-ondes.
US5874715A (en) * 1996-07-31 1999-02-23 Lg Electronics Inc. Heating apparatus in the form of an antenna array plate for a microwave oven
US5874706A (en) * 1996-09-26 1999-02-23 Tokyo Electron Limited Microwave plasma processing apparatus using a hybrid microwave having two different modes of oscillation or branched microwaves forming a concentric electric field
US7092988B1 (en) 1997-05-27 2006-08-15 Jeffrey Bogatin Rapid cooking oven with broadband communication capability to increase ease of use
US7493362B2 (en) 1997-05-27 2009-02-17 Turbochef Technologies, Inc. Rapid cooking oven with broadband communication capability to increase ease of use
US5990466A (en) * 1998-04-02 1999-11-23 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US6008483A (en) * 1998-10-09 1999-12-28 Turbochef Technologies, Inc. Apparatus for supplying microwave energy to a cavity
US8224892B2 (en) 2000-04-28 2012-07-17 Turbochef Technologies, Inc. Rapid cooking oven with broadband communication capability to increase ease of use
US20050210987A1 (en) * 2001-01-31 2005-09-29 Jennings William E Pressure measurement in microwave-assisted chemical synthesis
US6649889B2 (en) 2001-01-31 2003-11-18 Cem Corporation Microwave-assisted chemical synthesis instrument with fixed tuning
US6607920B2 (en) 2001-01-31 2003-08-19 Cem Corporation Attenuator system for microwave-assisted chemical synthesis
US6753517B2 (en) 2001-01-31 2004-06-22 Cem Corporation Microwave-assisted chemical synthesis instrument with fixed tuning
US20040221654A1 (en) * 2001-01-31 2004-11-11 Jennings William Edward Pressure measurement in microwave-assisted chemical synthesis
US6886408B2 (en) 2001-01-31 2005-05-03 Cem Corporation Pressure measurement in microwave-assisted chemical synthesis
US7208709B2 (en) 2001-01-31 2007-04-24 Cem Corporation Pressure measurement in microwave-assisted chemical synthesis
US6713739B2 (en) 2001-01-31 2004-03-30 Cem Corporation Microwave-assisted chemical synthesis instrument with fixed tuning
US6966226B2 (en) 2001-01-31 2005-11-22 Cem Corporation Pressure measurement in microwave-assisted chemical synthesis
US6960747B2 (en) * 2001-11-09 2005-11-01 Personal Chemistry I Uppsala Ab Microwave applicator system
AU2002347715B2 (en) * 2001-11-09 2007-01-18 Biotage Ab Microwave applicator system
WO2003040630A3 (en) * 2001-11-09 2003-12-04 Personal Chemistry I Uppsala Microwave applicator system
WO2003040630A2 (en) * 2001-11-09 2003-05-15 Personal Chemistry I Uppsala Ab Microwave applicator system
US7144739B2 (en) 2002-11-26 2006-12-05 Cem Corporation Pressure measurement and relief for microwave-assisted chemical reactions
US20040101441A1 (en) * 2002-11-26 2004-05-27 Cem Corporation Pressure measurement and relief for microwave-assisted chemical reactions
US9282594B2 (en) 2010-12-23 2016-03-08 Eastman Chemical Company Wood heater with enhanced microwave launching system
US9456473B2 (en) 2010-12-23 2016-09-27 Eastman Chemical Company Dual vessel chemical modification and heating of wood with optional vapor
US20160219653A1 (en) * 2015-01-27 2016-07-28 Samsung Electronics Co., Ltd. Cooking Apparatus and Controlling Method Thereof
US10231292B2 (en) * 2015-01-27 2019-03-12 Samsung Electronics Co., Ltd Cooking apparatus and controlling method thereof

Also Published As

Publication number Publication date
DD94864A5 (de) 1973-01-05
BE774075A (fr) 1972-02-14
DK136050C (de) 1978-01-02
AU466306B2 (en) 1975-10-23
NL7114369A (de) 1972-04-21
DK136050B (da) 1977-08-01
DE2151655A1 (de) 1972-04-20
DE2166290A1 (de) 1973-07-05
NO134027B (de) 1976-04-26
CH564300A5 (de) 1975-07-15
NO134027C (de) 1976-08-04
AU3476671A (en) 1973-05-03
DE2166290C3 (de) 1975-02-20
DE2166290B2 (de) 1974-07-04
GB1364734A (en) 1974-08-29
DE2151655B2 (de) 1976-01-29
SE343742B (de) 1972-03-13

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