US3798404A - Electronic oven with mode exciter - Google Patents

Electronic oven with mode exciter Download PDF

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Publication number
US3798404A
US3798404A US00317206A US3798404DA US3798404A US 3798404 A US3798404 A US 3798404A US 00317206 A US00317206 A US 00317206A US 3798404D A US3798404D A US 3798404DA US 3798404 A US3798404 A US 3798404A
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cavity
conductive member
mode
shaft
predetermined
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US00317206A
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English (en)
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D Simon
L Fitzmayer
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General Electric Co
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General Electric Co
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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
    • H05B6/72—Radiators or antennas
    • H05B6/725—Rotatable antennas
    • 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
    • H05B6/647—Aspects related to microwave heating combined with other heating techniques
    • H05B6/6482—Aspects related to microwave heating combined with other heating techniques combined with radiant heating, e.g. infrared heating
    • 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
    • H05B6/705—Feed lines using microwave tuning
    • 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
    • H05B6/72—Radiators or antennas
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Definitions

  • An electronic oven includes a boxlike enclosure defining a heating cavity therein, a microwave source coupled to an antenna centrally of the bottom wall of the cavity for radiating thereinto microwave energy of a predetermined wavelength for exciting a predetermined primary mode electromagnetic field in the cavity, a drive motor having a grounded conductive output shaft projecting into the cavity centrally of the top wall thereof coaxially with the antenna and parallel to the primary mode electric field, and a generally L- shaped conductive member having two interconnected leg portions disposed in a plane normal to the shaft, one of which leg portions is connected at the free end thereof to the inner end of the shaft for rotation about the axis thereof, the conductive element being responsive to rotation thereof in the primary mode of the electric field for exciting in the cavity two secondary modes complementary to the primary mode.
  • a generally W-shaped conductive element and a rectangular conductive element are also provided for effecting phase reversal of the secondary modes with respect to the primary mode as the element rotates.
  • a support rack is provided in the cavity having spacecl-apart parallel rods extending parallel to the direction of propagation of the electromagnetic field.
  • the present invention relates to an electronic oven and, more. particularly, to a device for providing a substantially uniform time-averaged electric field distribution in the oven cavity to facilitate uniform heating of material placed in the oven.
  • It is an important object of this invention to provide electronic heating apparatus comprising an enclosure including two opposed parallel walls and defining a heating cavity for receiving therein a body to beheated, an antenna disposed adjacent to one of the opposed walls and projecting into the cavity along an axis substantially perpendicular to the one wall, the antenna being adapted for coupling to an associated source of electromagnetic energy of a predetermined ultra-high frequency for transmitting the energy into the cavity to excite therein a predetermined primary electromagnetic field mode, a grounded conductive member disposed in the cavity adjacent to the other of the opposed walls, and drive means coupled to the conductive member for effecting rotation thereof about the axis of the antenna for exciting in the cavity a predetermined secondary mode complementary to the primary mode, whereby there is established within the cavity a substantially uniform time-averaged field distribution thereby to facilitate uniform heating of the associated body.
  • Another object of this invention is to provide an electronic heating apparatus of the type set forth, wherein the drive means includes a rotatably driven grounded conducted shaft extending into the cavity with the longitudinal axis thereof disposed substantially parallel to the electric field component ofthe primary mode, the conductive member being generally L-shaped and having two interconnected leg portions disposed in the cavity in a common plane substantially normal to the axis of the shaft, the shaft being connected to the conductive member at the free end of one of the leg portions thereof for effecting rotation thereof by the axis of the shaft.
  • the conductive member is generally W-shaped, and includes two interconnected identically constructed L- shaped sections all disposed in a common plane substantially normal to the axis of the shaft, the conductive member being responsive to continuous rotation thereof by the drive means for periodically reversing the phase relationships between the electric field components of the primary and secondary modes.
  • yet another object of the invention is to provide an electronic heating apparatus of the type set forth, wherein the conductive element is generally rectangular in shape, comprising four interconnected straight segments all disposed in the cavity in a common plane substantially normal to the axis of the shaft.
  • FIG. 1 is a side elevational view in partial section of an electric range incorporating therein an electronic heating apparatus constructed in accordance with and embodying the features of the present invention
  • FIG. 2 is an enlarged fragmentary bottom plan view of the oven broil unit and mode stirrer, taken along the line 2-2 in FIG. 1;
  • FIG. 3 is a reduced front perspective view of the oven enclosure showing the electric field pattern of the primary mode excited in the cavity by the microwave antenna;v
  • FIG. 4 is a view similar to FIG. 3, showing the mode stirrer in accordance with a first embodiment of the invention, and illustrating the electric field pattern of one of the secondary modes excited by the stirrer;
  • FIG. 5 is a view similar to FIG. 4, showing superimposed the primary mode electric field pattern of FIG. 3 and another one of the secondary modes excited by the mode stirrer of FIG. 4;
  • FIG. 6 is a diagrammatic representation of the relative composite field strength pattern established in the cavity by the stirrer of FIG. 4, as viewed from the top of the cavity;
  • FIG. 7 is a diagrammatic front elevational view of the composite field pattern established in the oven cavity by the stirrer of FIG. 4;
  • FIG. 8 is a top plan diagrammatic representation of a mode stirrer according to a second embodiment of the invention, and illustrating the phase orientation of one of the secondary modes with respect to the primary mode;
  • FIG. 9 is a view similar to FIG. 8, showing the mode stirrer in a position rotated 180 from the position illustrated in FIG. 8;
  • FIG. 10 is a diagrammatic representation of the relative composite field strength pattern in the oven cavity asviewed from the top thereof when the mode stirrer of FIG. 8 is disposed in the positions illustrated in FIGS. 8 and 9;
  • FIG. 11 is a view similar to FIG. 8 showing the mode stirrer in a position rotated clockwise from the position illustrated in FIG. 8;
  • FIG. 12 is a view similar to FIG. 8 showing the mode stirrer illustrated in a position rotated 270 from the position shown in FIG. 8;
  • FIG. 13 is a diagrammatic representation, similar to FIG. 10 showing the relative composite field strength pattern when the mode stirrer of FIG. 8 is in the positions illustrated in FIGS. 11 and 12;
  • FIG. 14 is a top plan diagrammatic representation of a mode stirrer according to a third embodiment of the invention, and shown in a position which produces the field strength pattern illustrated in FIG. 10;
  • FIG. 15 is a view similar to FIG. 14 showing the mode stirrer in another position which produces the field strength pattern of FIG. 10;
  • FIG. 16 is a view similar to FIG. 14 showing the mode stirrer in a position which produces the field strength pattern of FIG. 13;
  • FIG. 17 is a view similar to FIG. 14 showing the mode stirrer in another position which produces the field strength pattern of FIG. 13.
  • FIGS. 1 and 2 of the drawings there is illustrated an electric range, generally designated by the numeral 50.
  • the detailed construction of the electric range 50 is disclosed in the copending US. application Ser. No. 256,093 of Roland V. Fowler et al., filed May 23, 1972, entitled MULTI- PLE POSITION DOOR LATCH MECHANISM, and assigned to the assignee of the present invention. Accordingly, only so much of the structure of the range 50 will herein be described as is necessary for an understanding of the present invention.
  • the range 50 is generally box-like in shape and includes a top wall 51, a bottom wall 52, an upstanding rear wall 53, a front wall 55, and a pair of opposed upstanding side walls 54.
  • Mounted on the top wall 51 of the range 50 is a plurality of standard electrical resistance heating units, these units and the other heating apparatus of the range 50 being controlled by a set of controls carried by a control panel 56 mounted on the top wall 51 at the rear end thereof.
  • the front wall 55 has a relatively large rectangular upper opening 58 and a relative small rectangular lower opening 59 therein for providing access to the interior of the range 50.
  • a door 60 is mounted on the front wall 55 for movement between an open position (not shown) providing access to the interior of the range 50 and a closed position illustrated in FIG. 1 disposed in the doorway for closing the opening 58.
  • a door 62 is mounted on the front wall 55 adjacent to the opening 59 for movement between an open position (not shown) providing access to the interior of the range 50 and a closed position, illustrated in FIG. 1, for closing the opening 59.
  • Connected to the upper mounting flange 63 and extending rearwardly therefrom substantially normal to the front wall 55 is a rectangular partition 65 for dividing the interior of the range 50 into an upper machinery compartment 66 and a lower open compartment 67.
  • a latch assembly 68 mounted in the upper machinery compartment 66 upon the partition 65 is a latch assembly 68 for latching the front door 60 in the closed position thereof.
  • a generally boxlike metallic oven enclosure mounted in the lower oven compartment 67 a slight distance below the partition 65 is a generally boxlike metallic oven enclosure, generally designated by the numeral 70, the oven enclosure being substantially in the shape of a rectangular parallelepiped and including a top wall 71, a bottom wall 72, an upstanding rear wall 73, and a pair of opposed upstanding side walls 74, the front end of the oven enclosure 70 being open at the front end thereof and communicating with the opening 58 ofthe front wall 55 of the range 50.
  • the top and bottom walls 71 and 72 and the side walls 74 of the enclosure 70 are connected at the front edges thereof to the mounting flanges 63 and 64 for supporting and positioning the oven enclosure 70 in the compartment 67.
  • the side walls 74 of the oven enclosure 70 are provided on the inner surfaces thereof with mounting means (not shown) for supporting a rack 75, the
  • a rack 75 comprising a plurality of laterally spaced-apart parallel rods 77 extending parallel to the side wall 74 and interconnected at the front and rear ends thereof by end rods 78 disposed substantially parallel to the rear wall 73 (see FIGS. 3 and 4).
  • a broil unit 79 Disposed within the oven enclosure 70 closely adjacent to the top wall 71 and substantially parallel thereto is a broil unit 79 secured to the top wall 71 by means of mounting clips 71a, the broil unit 79 preferably being a resistance heating element arranged in the serpentine configuration illustrated in FIG. 2.
  • the bottom wall 72 of the oven enclosure 70 is spaced a predetermined distance above the bottom wall 52 of the range 50 and cooperates therewith to define there-between a lower machinery compartment 88, access to which is provided through the front opening 59.
  • a component tray 81 having mounted thereon a magnetron generator for generating electromagnetic energy of a predetermined ultrahigh frequency, preferably 915 MI-Iz.
  • the magnetron 80 is energized by a power supply unit 82 which is also mounted on the component tray 81.
  • the magnetron 80 and the power supply unit 82 may be of the type disclosed in the copending US. Pat. application Ser. No. 181,144 of James E. Pope, filed Mar. 20, 1962, entitled Control and Power Supply Systems for Magnetron Devices, and assigned to the assignee of the present invention.
  • a blower 83 for directing a stream of cooling air over the magnetron 80 and the power supply 82 for effecting cooling thereof in a well-known manner.
  • a waveguide 84 Coupled to the RF output terminals the magnetron 80 is a waveguide 84, the upper end of which is received in a complementary opening disposed centrally of the bottom wall 72 of the oven enclosure 70 and is coupled to an antenna, generally designated by the numeral 85, for radiating the microwave 70 and the closed front door 60.
  • the antenna 85 preferably includes a cylindrical metal post 86 extending vertically upwardly into the oven cavity substantially perpendicular to the bottom wall 72 and coaxially connected at the upper end thereof to a circular slightly concave disk-like capacitive member 87.
  • the post 86 has an electrical length approximately equal to 1/8 of the wavelength A of the microwave energy generated by the magnetron 80, the total electrical length of the antenna 85 being approximately equal to M4.
  • an electric drive motor 90 having a grounded conductive output shaft extending vertically downwardly through a complementary opening disposed centrally in the top wall 71 of the oven enclosure 70.
  • the output shaft 95 is preferably disposed substantially coaxially with the post 86 of the antenna 85 and extends a predetermined distance into the oven into the heating cavity.
  • the shaft 95 has an electrical length approximately equal to M8.
  • a mode stirrer or exciter Connected to the shaft 95 at the bottom end thereof is a mode stirrer or exciter according to one of the embodiments of this invention, generally designated either by the numeral 100, 200 or 300, the embodiment 200 being illustrated in FIGS. 1 and 2.
  • the mode exciters 100, 200 and 300 will be described in numerical order.
  • the mode exciter 100 is generally L-shaped and is preferably integrally formed of a single piece of conductive material such as metal, the mode exciter 100 including a relatively long leg 101 and a relatively short leg 105, the leg 105 being disposed substantially normal to the leg 101.
  • the mode exciter 100 is formed of a relatively thin flat piece of metal having a width and thickness sufficient to provide appropriate mechanical strength and current-carrying capacity, the width however preferably being less than or equal to )t/ 8.
  • the mode exciter 100 is disposed in a plane substantially parallel to the top wall 71 of the oven enclosure 70 and is connected at the free end of the leg 101 to the bottom end of the shaft 95 for rotation therewith by the drive motor 90.
  • the leg 101 preferably has an electrical length approximately equal to 3M8, while the short leg 105 preferably has an electrical length approximately equal to )t/4, whereby the total electrical length of the shaft 95 and the mode exciter 100 is approximately equal to 3M4.
  • the length, width and height of the heating cavity defined by the oven enclosure 70 are all preferably greater than A.
  • the dimensions of the heating cavity and the dimensions of the antenna 75 are such that when the microwave energy is radiated into the cavity by'the antenna 75, the heating cavity acts as a cavity resonator and there is established therein the Tli mode at approximately 920 MHz, the electric field component of which is diagrammatically illustrated in solid line in FIGS. 3 and 5 and is generally designated by the numeral 110, the direction of propagation of the electromagnetic waves being indicated by the double-ended arrows in FIGS. 3 through 5.
  • the electric field component 110 of the TE mode is maximum at the middle of the heating cavity and is minimum at the front and rear ends thereof, with the direction of the field 100 being substantially parallel to the axisof the grounded shaft
  • the mode exciter 100 is itself excited by the electric field 110 and in turn excites secondary modes in the heating cavity. More particularly, when the short leg 105 of the mode exciter 100 is disposed in positions parallel to the rear wall 73, it excites in the oven heating cavity the TB, mode at approximately 930 MHz, the electric field component of which is diagrammatically illustrated in FIG. 4 and is generally designated by the numeral 115. It can be seen from FIG.
  • the electric field 115 is maximum adjacent to the front and rear ends of the cavity and is minimum at the center thereof.
  • the long leg 101 of the mode exciter 100 is disposed in positions substantially parallel to the back wall 73, it excites in the cavity the TF mode at approximately 960 MHz, the electric field component of this mode being diagrammatically illustrated in broken line in FIG. 5 and generally designated by the numeral 130.
  • the electric field 130 like the electric field 110 is maximum at the center of the heating cavity and is minimum adjacent the front and rear ends thereof.
  • both the TE, and the TE secondary modes are complementary to the primary TE mode and cooperate therewith to equalize the electric field pattern in the heating cavity. More particularly, it will be appreciated that, as the secondary modes TE, and TE are periodically excited as the mode exciter is rotated in the heating cavity, the electric fields of the several modes add so that the resultant time-averaged electric field distribution in the oven cavity will be equalized, thereby facilitating more even heating of food placed in the oven cavity to be cooked.
  • the mode exciter 200 is generally W-shaped and comprises two identically constructed L-shaped sections, each of which is substantially identical to the mode exciter 100. More particularly, the mode exciter 200 includes a first long leg portion 201 being integral at one end thereof with a first short leg portion 205 disposed substantially normal thereto. Connected to the first long leg portion 201 at the other end thereof is one end of a second long leg portion 202 extending from the first leg portion 201 substantially normal thereto and in a direction opposite to the direction of the short leg portion 205.
  • a second short leg portion 206 Integral with the second long leg portion 202 at the other end thereof and extending therefrom substantially normal thereto in a direction opposite to the direction of the first long leg portion 201 is a second short leg portion 206.
  • the leg portions 201, 202, 205 and 206 of the mode stirrer 200 are all disposed in a common plane substantially parallel to the top wall 71 of the oven enclosure 70, with the mode exciter 200 being connected at a point 207 at the junction of the long leg portions 201 and 202 to the lower end of the shaft 95 for rotation therewith by the motor 90.
  • the mode exciter 200 acts in the same manner as two of the L-shaped mode exciters 100. More particularly, the short leg portions 205 and 206 excite the secondary TE mode when they are disposed substantially parallel to the front and rear walls of the oven cavity, while when the long leg portions 201 and 202 are disposed parallel to the front and rear walls, the secondary TE mode is excited. The interaction between these two modes effects a periodic phase reversal of the orientation of the TE mode with respect to the TE mode, thereby evening out or equalizing the diagonal distortion of the field as illustrated in FIG. 6.
  • the polarity of the mode exciter 200 is determined by the TE electric field, as indicated by the signs in FIGS. 8, 9, 11 and 12.
  • the mode exciter 200 When the mode exciter 200 is disposed in the positions illustrated in FIGS. 8 and 9, which positions are 180 apart, it will excite the TE mode with the electric field E as shown.
  • the field strength pattern of the resultant electric field in the oven cavity will be as indicated diagrammatically in FIG. 10, with the strong field regions being located at the left rear and right front portions of the cavity.
  • the mode exciter 200 is disposed in the positions illustrated in FIGS. 11 and 12
  • the field strength pattern of the resultant electric field in the oven cavity will be as indicated in FIG. 13, with the strong field regions being at the left front and right rear portions of the heating cavity.
  • FIGS. 14 through 17 of the drawings there is illustrated a third embodiment of the mode exciter of the present invention, generally designated by the numeral 300, the mode exciter 300 affording an alternative structure for effecting the periodic reversal of the phase relationship between the TE, and TE mode electric fields.
  • the mode exciter 300 is generally rectangular in shape and includes four interconnected straight segments 30], 302, 305 and 306. While the mode exciter 300 is illustrated in the drawings as having a substantially square configuration, it will be understood that other rectangular configurations could also be used.
  • the segments 301, 302, 305 and 306 are all disposed in a common plane substantially parallel to the top wall 71 of the oven enclosure 70, with the mode exciter 300 being connected at one corner 307 thereof to the lower end of the shaft 95 for rotation therewith 90.
  • the total electrical length of the segments 301 and 305 is approximately equal to M8, whereby the total electrical length of the segments 302 and 306 is also equal to approximately 5M8.
  • the total electrical length of the shaft 95 plus the distance along the mode exciter 200 from the point 307 to the opposite corner thereof is approximately equal to 3M4.
  • the mode exciter 300 operates essentially the same way as the mode exciter 200, with the segments 301 and 305 acting in essentially the same manner as one of the L- shaped mode exciters 100 for exciting the TE, and TE, modes, with the segments 302 and 306 operating as another of the L-shaped mode exciters 100.
  • the W-shaped mode exciter 200 In the event of fast rotation (60 to 300 r.p.m.) of the W-shaped mode exciter 200, it may be necessary to mechanically balance the mode exciter. This may be accomplished by providing a straight balance leg 210 extending from the junction 207 away from the legs 201 and 202 and substantially bisecting the angle therebetween, as illustrated in broken line in FIG. 2.
  • the balance leg 210 has an effective electrical length of approximately M2, whereby the mode exciter 200 is not electrically affected, since the M2 leg will exhibit a high impedance at the junction 207.
  • the orientation of the rods 77 of the rack is such that the rack 75 does not interfere with the excitation of the several modes in the heating cavity and the propagation of the electric field waves therein. More particularly, since the rods 77 are disposed substantially parallel to the direction of propagation as indicated by the arrow 99, the rack 75 will not interfere with the primary TE mode or with the excitation of the secondary TE and TE modes.
  • the primary and secondary mode excitation could also be achieved by utilizing only a rotating antenna in the shape of one of the mode exciters 100, 200 or 300. With that configuration, a separate mode exciter would not be necessary.
  • the grounded conductive shaft may be provided with an equivalent electrical ground such as a choke joint in place of the actual ground described.
  • a rotating mode stirrer disposed at one end of the heating cavity and arranged substantially coaxially with a radiating antenna disposed at the opposite end of the cavity.
  • Electronic heating apparatus comprising an enclo sure including two opposed parallel walls and defining a heating cavity for receiving therein a body to be heated, an antenna disposed in said cavity adjacent to one of said opposed walls and having a longitudinal axis substantially perpendicular to said one wall, said antenna being adapted for coupling to an associated' source of electromagnetic energy of a predetermined ultra-high frequency for transmitting said energy into said cavity to excite therein a predetermined primary electromagnetic field mode, a grounded conductive member disposed in said cavity adjacent to the other of said opposed walls, and drive means coupled to said conductive member for effecting rotation thereof about said axis of said antenna for exciting in said cavity a predetermined secondary mode complementary to said primary mode, whereby there is established within said cavity a substantially uniform time-averaged field distribution thereby to facilitate uniform heating of the associated body.
  • said antenna includes a cylindrical post having the longitudinal axis thereof disposed substantially normal to said one wall, and a capacitive disk-like member connected to said post at the inner end thereof substantially coaxially therewith.
  • said antenna includes a cylindrical post having the longitudinal axis thereof disposed substantially normal to said one wall, and a capacitive disk-like member connected to said post at the inner end thereof substantially coaxially therewith, said drive means including a grounded shaft extending inwardly of said other wall substantially coaxially with said antenna post, said shaft being connected to said conductive member for effecting rotation thereof.
  • Electronic heating apparatus comprising an enclosure defining a heating cavity for receiving therein a body to be heated, source means electrically coupled to said heating cavity for transmitting thereinto ultrahigh frequency electromagnetic energy of a predetermined wavelength to excite a predetermined primary electromagnetic field mode in said cavity, drive means including a rotatably driven grounded conductive shaft extending into said cavity with the longitudinal axis thereof disposed substantially parallel to the electric field component of said primary mode, a generally L- shaped conductive member disposed in said cavity and having two interconnected leg portions intersecting at an angle and lying in a common plane substantially normal to the axis of said shaft, said shaft being connected to said conductive member at the free end of one of the said leg portions thereof for effecting rotation thereof about the axis of said shaft, said conductive member being responsive to continuous rotation thereof by said drive means for interaction with said primary mode electric field periodically to excite in said cavity predetermined secondary electromagnetic field modes complementary to said primary mode, whereby there is established within said cavity a substantially uniform time-averaged field distribution to facilitate uniform heating of the associated body.
  • said enclosure includes six walls arranged substantially to form a rectangular parallelopiped having internal dimensions greater than said predetermined wave length, said source means being disposed adjacent to the bottom wall of said enclosure and said conductive member being disposed adjacent to the top wall of said enclosure.
  • said enclosure includes six walls arranged substantially to form a rectangular parallelepiped having dimensions greater than said predetermined wave length, said source means being disposed adjacent to the bottom wall of said enclosure and said conductive member being disposed adjacent to the top wall of said enclosure, said shaft having an electric length approximately equal to H8 of said predetermined wave length, said one leg portion of said conductive member having an electrical length approximatly equal to 3/ 8 of said predetermined wave length, the other leg portion of said conductive member having an electrical length approximately equal to 1/4 of said predetermined wave length.
  • Electronic heating apparatus comprising an enclosure defining a heating cavity for receiving therein a body to be heated, source means electrically coupled to said heating cavity for transmitting thereinto ultrahigh frequency electromagnetic energy of a predetermined wavelength to excite a predetermined primary electromagnetic field mode in said cavity, drive means including a rotatably driven grounded conductive shaft extending into said cavity with the longitudinal axis thereof disposed substantially parallel to the electric field component of said primary mode, a conductive member disposed in said cavity and including two interconnected generally L-shaped sections, each of said sections including first and second leg portions intersecting at an angle and lying in a common plane substantially normal to the axis of said shaft, said the first leg portions of said sections being interconnected at the free ends thereof and with said second leg portions of said sections extending in opposite directions, said shaft being connected to said conductive member at the intersection of said first leg portions thereof for effecting rotation thereof about the axis of said shaft, said conductive member being responsive to continuous rotation thereof by said drive means for interaction with said primary mode electric field periodically to excite in said cavity predetermined secondary
  • Electronic heating apparatus comprising an enclosure defining a heating cavity for receiving therein a body to be heated, source means electrically coupled to said heating cavity for transmitting thereinto ultrahigh frequency electromagnetic energy of a predetermined wavelength to excite a predetermined primary electromagnetic field mode in said cavity, drive means including a rotatably driven grounded conductive shaft extending into said cavity with the longitudinal axis thereof disposed substantially parallel to the electric field component of said primary mode, a conductive member including four straight segments all disposed in said cavity in a common plane substantially normal to the axis of said shaft and being interconnected to form a hollow rectangle, said shaft being connected to said conductive member at one of the corners thereof for effecting rotation thereof about the axis of said shaft, said conductive member being responsive to continuous rotation thereof by said drive means for interaction with said primary mode electric field periodically to excite in said cavity predetermined secondary electromagnetic field modes complementary to said primary mode, said conductive member being further responsive to continuous rotation thereof by said drive means for periodically reversing the phase relationships of the electric field components of said primary and secondary modes, whereby

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Constitution Of High-Frequency Heating (AREA)
US00317206A 1972-12-21 1972-12-21 Electronic oven with mode exciter Expired - Lifetime US3798404A (en)

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CA (1) CA957732A (ja)
DE (1) DE2363045A1 (ja)
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Cited By (12)

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US3845267A (en) * 1974-01-04 1974-10-29 Gen Electric Microwave oven with waveguide feed
US3855440A (en) * 1974-01-04 1974-12-17 Gen Electric Microwave oven having preferred modes
US3975606A (en) * 1973-12-18 1976-08-17 Matsushita Electric Industrial Co., Ltd. Microwave oven with uniform electric field distribution
US4147912A (en) * 1977-02-07 1979-04-03 Roper Corporation Shaped antenna for energy distribution in a microwave cooking cavity
US4458126A (en) * 1982-03-30 1984-07-03 General Electric Company Microwave oven with dual feed excitation system
US4476362A (en) * 1975-05-19 1984-10-09 Matsushita Electric Industrial Co., Ltd. High frequency heating apparatus
SG91243A1 (en) * 1995-09-13 2002-09-17 Suisaku Ltd Self tuning material and method for manufacturing the same
EP2645001A1 (en) * 2010-11-25 2013-10-02 Panasonic Corporation Microwave heating device
EP2738474A1 (en) * 2011-07-25 2014-06-04 Panasonic Corporation Microwave heating device
US20170171922A1 (en) * 2014-07-10 2017-06-15 Panasonic Intellectual Property Management Co., Ltd. Microwave heating device
TWI675609B (zh) * 2018-12-26 2019-10-21 財團法人工業技術研究院 分布式微波相位控制方法
US20220086963A1 (en) * 2019-01-04 2022-03-17 Haier Smart Home Co., Ltd. Heating device

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Publication number Priority date Publication date Assignee Title
JPS5213147A (en) * 1975-07-18 1977-02-01 Matsushita Electric Ind Co Ltd High-frequency heating equipment
JPS52100632A (en) * 1976-02-19 1977-08-23 Matsushita Electric Ind Co Ltd High frequency heater
JPS5934071Y2 (ja) * 1977-10-14 1984-09-21 松下電器産業株式会社 高周波加熱装置
JPS56167295A (en) * 1980-05-28 1981-12-22 Matsushita Electric Ind Co Ltd High frequency heater
JP2015049943A (ja) * 2013-08-29 2015-03-16 株式会社日立パワーソリューションズ マイクロ波加熱装置

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US3281567A (en) * 1963-10-28 1966-10-25 Litton Prec Products Inc Oven protective device
US3517152A (en) * 1968-10-14 1970-06-23 Sage Laboratories Microwave oven field alteration
US3643055A (en) * 1969-12-01 1972-02-15 Matsushita Electric Ind Co Ltd High-frequency heating apparatus
US3716687A (en) * 1970-08-18 1973-02-13 Hirst Microwave Ind Ltd Method and apparatus for cooking

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Publication number Priority date Publication date Assignee Title
US3281567A (en) * 1963-10-28 1966-10-25 Litton Prec Products Inc Oven protective device
US3517152A (en) * 1968-10-14 1970-06-23 Sage Laboratories Microwave oven field alteration
US3643055A (en) * 1969-12-01 1972-02-15 Matsushita Electric Ind Co Ltd High-frequency heating apparatus
US3716687A (en) * 1970-08-18 1973-02-13 Hirst Microwave Ind Ltd Method and apparatus for cooking

Cited By (15)

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Publication number Priority date Publication date Assignee Title
US3975606A (en) * 1973-12-18 1976-08-17 Matsushita Electric Industrial Co., Ltd. Microwave oven with uniform electric field distribution
US3845267A (en) * 1974-01-04 1974-10-29 Gen Electric Microwave oven with waveguide feed
US3855440A (en) * 1974-01-04 1974-12-17 Gen Electric Microwave oven having preferred modes
US4476362A (en) * 1975-05-19 1984-10-09 Matsushita Electric Industrial Co., Ltd. High frequency heating apparatus
US4147912A (en) * 1977-02-07 1979-04-03 Roper Corporation Shaped antenna for energy distribution in a microwave cooking cavity
US4458126A (en) * 1982-03-30 1984-07-03 General Electric Company Microwave oven with dual feed excitation system
SG91243A1 (en) * 1995-09-13 2002-09-17 Suisaku Ltd Self tuning material and method for manufacturing the same
EP2645001A1 (en) * 2010-11-25 2013-10-02 Panasonic Corporation Microwave heating device
EP2645001A4 (en) * 2010-11-25 2014-05-07 Panasonic Corp MICROWAVE HEATING DEVICE
EP2738474A1 (en) * 2011-07-25 2014-06-04 Panasonic Corporation Microwave heating device
EP2738474A4 (en) * 2011-07-25 2014-12-31 Panasonic Corp microwave heating
US20170171922A1 (en) * 2014-07-10 2017-06-15 Panasonic Intellectual Property Management Co., Ltd. Microwave heating device
US11153943B2 (en) * 2014-07-10 2021-10-19 Panasonic Intellectual Property Management Co., Ltd. Microwave heating device
TWI675609B (zh) * 2018-12-26 2019-10-21 財團法人工業技術研究院 分布式微波相位控制方法
US20220086963A1 (en) * 2019-01-04 2022-03-17 Haier Smart Home Co., Ltd. Heating device

Also Published As

Publication number Publication date
FR2211834A1 (ja) 1974-07-19
DE2363045A1 (de) 1974-07-04
JPS49101945A (ja) 1974-09-26
CA957732A (en) 1974-11-12

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