US3351730A - Energy seal for microwave ovens - Google Patents

Energy seal for microwave ovens Download PDF

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Publication number
US3351730A
US3351730A US438191A US43819165A US3351730A US 3351730 A US3351730 A US 3351730A US 438191 A US438191 A US 438191A US 43819165 A US43819165 A US 43819165A US 3351730 A US3351730 A US 3351730A
Authority
US
United States
Prior art keywords
door
wall
recesses
oven
recess
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US438191A
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English (en)
Inventor
Pahlman Kurt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
North American Philips Co Inc
Original Assignee
US Philips Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3351730A publication Critical patent/US3351730A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/76—Prevention of microwave leakage, e.g. door sealings
    • H05B6/763—Microwave radiation seals for doors
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0007—Casings
    • H05K9/0015—Gaskets or seals

Definitions

  • a microwave oven having means for sealing the oven doorway to prevent the leakage of microwave energy comprises, providing opposed recesses in the mating surfaces of the door and the oven wall surrounding the oven doorway, each of which is one-fourth wavelength'deep at the frequency of the microwave. energy.
  • the present invention relates to a sealing arrangement utilized in microwave stoves for preventing leakage of .microwave energy between a stove door and the edge portion of the oven wall surrounding the door opening in the stove.
  • the invention has for an object to produce a simple and small sealing device for microwavestoves which also is effective over a large frequency range and has large mechanical tolerances, in particular with respect to the size of the gap between the stove door and the edge portions around the stove opening.
  • an improved seal is achieved by providing substantially equal recesses in the electrically conductive material and having a depth equal to approximately wave length of the microwave energy coming from the inside of the stove, and appearing in the said recesses.
  • the recesses are arranged in opposite portions of the edge of the stove door and the edge portions around the opening of the stove so that the recesses are open against each other and situated opposite each other in the closed condition of the door.
  • reference numeral 1 designates a side wall enclosing the heating cavity 2 of a microwave stove.
  • the front side of the'stove is provided with a-rectangular opening which can be closed by means of a door 3.
  • This consists of a door frame 4 extending around the opening and a thin metal sheet 5 covering the rectangular opening formed within the said door frame.
  • the metal sheet 5 may suitably be perforated in order to make possible observation of the food situated within the stove.
  • both the door-and the-portions of the side wall'of thestove surrounding theopening are provided with recesses 6 and 7, respectively, which formed.
  • the recesses t6, 7 are filled with a suitable dielectric material, as araldite or the like.
  • the dielectric decreases the dimensions of the recesses, and on the other hand it prevents the collection of dirt within the recesses.
  • the said recesses 6 and 7 each have a depth of 20 mm. corresponding substantially to a quarter of a wave length of the high frequency energy coming from the inside of the stove, account being taken of the filling material within the recesses.
  • the width of the recesses amounts in the said embodiment to 16 mm.
  • the door is mechanically actuated so that with the door closed, gaps 8 and 9, respectively, of some millimeters is formed both at the input side of the cavity 6, 7 and at the output side of the said cavity, as seen in the direction of propagation of the leaking energy.
  • the gap 8 at the input side should not be made too small, because sparking then may appear between opposite surfaces of the. side wall 1 and the door 3 due to the electromagnetic energy which is applied from the inside of the stove.
  • the said cavity 6, 7 acts as a very high impedance for the substantially plane-polarized electromagnetic energy coming from the stove. As a result, a very small quantity of energy can pass through the gap 8. Due to the fact that both the depth and the width of the recesses 6, 7 is approximately equal to a quarter of a wave length, the described sealing device may be regarded as a combination of a quarter wave stub (small short circuited wave guide section) and a quarter wave transformer. This is one of the reasons for the effective sealing properties of the device. Measurements have furthermore shown that the device is effective over a very wide frequency range.
  • a recess 10 containing a lossy material may suitably be arranged beyond the said cavity 6, 7 as seen in the direction of energy propagation.
  • the recess 10 with lossy material may possibly be missing at that side where the door hinges are situated because the gap at this side cannot increase appreciably before the high frequency source is disconnected.
  • a microwave oven comprising a metallic walled heating chamber having an access aperture in one wall of said chamber, a metallic door adjacent to and overlapping said aperture to provide a pair of spaced confronting planar surfaces defining a gap about the periphery of said aperture in the closed position of the door, said one wall having a recess therein extending about the periphery of said access aperture, said door having a recess therein extending about the periphery of the surface facing said wall and in confronting relationship with said wall recess, the depth of each of said recesses being approximately one-fourth wavelength at the frequency of the oven microwave energy.
  • one of said confronting surfaces includes a second recess filled with a lossy dielectric material and extending coaxially about a substantial portion of the first recess in said one surface.
  • a microwave oven comprising a metallic walled structure defining a heating chamber having an access aperture in one wall thereof, a door adapted to 'close said aperture and having a conductive surface completely covering and overlapping said aperture but spaced from the surface of said one wall around the opening so as to provide a gap between said door and said one wall in the closed position of the door, said one wall having an annular channel therein extending around the periphery of said access aperture, said door having an annular channel in the surface thereof facing said one wall and extending in opposed relationship to said wall channel to form therewith a continuous cavity extending about the access aperture, the depth of each of said channels being approximately one-fourth wavelength at the frequency of the oven microwave energy.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Electric Ovens (AREA)
US438191A 1964-03-10 1965-03-09 Energy seal for microwave ovens Expired - Lifetime US3351730A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE298964 1964-03-10

Publications (1)

Publication Number Publication Date
US3351730A true US3351730A (en) 1967-11-07

Family

ID=20261153

Family Applications (1)

Application Number Title Priority Date Filing Date
US438191A Expired - Lifetime US3351730A (en) 1964-03-10 1965-03-09 Energy seal for microwave ovens

Country Status (7)

Country Link
US (1) US3351730A (US20030204162A1-20031030-M00001.png)
BE (1) BE660798A (US20030204162A1-20031030-M00001.png)
CH (1) CH440489A (US20030204162A1-20031030-M00001.png)
DE (1) DE1540977A1 (US20030204162A1-20031030-M00001.png)
FR (1) FR1428346A (US20030204162A1-20031030-M00001.png)
GB (1) GB1044455A (US20030204162A1-20031030-M00001.png)
NL (1) NL6502729A (US20030204162A1-20031030-M00001.png)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US3662139A (en) * 1970-03-04 1972-05-09 Varian Associates Cavity resonator having means for reducing leakage of r.f. energy at a covered access point
US3678238A (en) * 1970-04-23 1972-07-18 Sanyo Electric Co High frequency heating apparatus
JPS5018182Y1 (US20030204162A1-20031030-M00001.png) * 1970-12-16 1975-06-04
JPS5027944Y1 (US20030204162A1-20031030-M00001.png) * 1974-11-05 1975-08-19
US4132239A (en) * 1977-07-05 1979-01-02 Raytheon Company Fluid valve for microwave devices
US4166207A (en) * 1977-05-31 1979-08-28 Whirlpool Corporation Microwave generating device--door seal
US4471194A (en) * 1971-05-20 1984-09-11 Matsushita Electric Industrial Co., Ltd. Electromagnetic energy seal for high frequency heating apparatus
EP1143781A1 (en) * 2000-03-30 2001-10-10 Pioneer Corporation Door opening and closing apparatus
JP2002374101A (ja) * 2001-06-13 2002-12-26 New Japan Radio Co Ltd チョークフランジ
US20120138600A1 (en) * 2009-08-20 2012-06-07 Panasonic Corporation Electromagnetic wave heating device
JP2012156742A (ja) * 2011-01-26 2012-08-16 Nec Corp 導波管接続構造

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL6502729A (US20030204162A1-20031030-M00001.png) * 1964-03-10 1965-09-13
DE102004052798B4 (de) * 2004-11-02 2006-08-31 Electrolux Home Products Corp. N.V. Garofen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3182164A (en) * 1962-02-28 1965-05-04 Raytheon Co Electromagnetic energy seal
US3196242A (en) * 1961-10-25 1965-07-20 Philips Corp High-frequency oven door seal
US3219747A (en) * 1963-02-08 1965-11-23 James H Mcadams Shielding arrangement with wave guide below cutoff
US3249731A (en) * 1963-11-14 1966-05-03 Westinghouse Electric Corp Oven
GB1044455A (en) * 1964-03-10 1966-09-28 Philips Electronic Associated Microwave ovens

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3196242A (en) * 1961-10-25 1965-07-20 Philips Corp High-frequency oven door seal
US3182164A (en) * 1962-02-28 1965-05-04 Raytheon Co Electromagnetic energy seal
US3219747A (en) * 1963-02-08 1965-11-23 James H Mcadams Shielding arrangement with wave guide below cutoff
US3249731A (en) * 1963-11-14 1966-05-03 Westinghouse Electric Corp Oven
GB1044455A (en) * 1964-03-10 1966-09-28 Philips Electronic Associated Microwave ovens

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US3662139A (en) * 1970-03-04 1972-05-09 Varian Associates Cavity resonator having means for reducing leakage of r.f. energy at a covered access point
US3678238A (en) * 1970-04-23 1972-07-18 Sanyo Electric Co High frequency heating apparatus
JPS4939571B1 (US20030204162A1-20031030-M00001.png) * 1970-04-23 1974-10-26
JPS5018182Y1 (US20030204162A1-20031030-M00001.png) * 1970-12-16 1975-06-04
US4471194A (en) * 1971-05-20 1984-09-11 Matsushita Electric Industrial Co., Ltd. Electromagnetic energy seal for high frequency heating apparatus
JPS5027944Y1 (US20030204162A1-20031030-M00001.png) * 1974-11-05 1975-08-19
US4166207A (en) * 1977-05-31 1979-08-28 Whirlpool Corporation Microwave generating device--door seal
US4132239A (en) * 1977-07-05 1979-01-02 Raytheon Company Fluid valve for microwave devices
EP1143781A1 (en) * 2000-03-30 2001-10-10 Pioneer Corporation Door opening and closing apparatus
JP2002374101A (ja) * 2001-06-13 2002-12-26 New Japan Radio Co Ltd チョークフランジ
US20120138600A1 (en) * 2009-08-20 2012-06-07 Panasonic Corporation Electromagnetic wave heating device
EP2469976A1 (en) * 2009-08-20 2012-06-27 Panasonic Corporation Electromagnetic wave heating device
EP2469976A4 (en) * 2009-08-20 2014-01-22 Panasonic Corp DEVICE FOR HEATING BY ELECTROMAGNETIC WAVES
JP2012156742A (ja) * 2011-01-26 2012-08-16 Nec Corp 導波管接続構造

Also Published As

Publication number Publication date
NL6502729A (US20030204162A1-20031030-M00001.png) 1965-09-13
BE660798A (US20030204162A1-20031030-M00001.png) 1965-09-08
CH440489A (de) 1967-07-31
GB1044455A (en) 1966-09-28
FR1428346A (fr) 1966-02-11
DE1540977A1 (de) 1970-03-19

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