US3803377A - Fail safe door seal microwave oven - Google Patents

Fail safe door seal microwave oven Download PDF

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Publication number
US3803377A
US3803377A US00244056A US24405672A US3803377A US 3803377 A US3803377 A US 3803377A US 00244056 A US00244056 A US 00244056A US 24405672 A US24405672 A US 24405672A US 3803377 A US3803377 A US 3803377A
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US
United States
Prior art keywords
door
microwave
housing
microwave oven
opening
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
US00244056A
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English (en)
Inventor
M Nakano
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
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 Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3803377A publication Critical patent/US3803377A/en
Anticipated expiration legal-status Critical
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
    • H05B6/76—Prevention of microwave leakage, e.g. door sealings
    • H05B6/763—Microwave radiation seals for doors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
    • F24C15/00—Details
    • F24C15/02—Doors specially adapted for stoves or ranges
    • F24C15/021—Doors specially adapted for stoves or ranges sealings for doors or transparent panel

Definitions

  • the present invention relates to door seals for microwave ovens and is characterized in that a capacitive seal and choke seal are improved and used in combination to limit the amount of leakage microwave energy below the predetermined permissible level.
  • FIG. I is a general perspective view of a microwave oven according to the present invention.
  • FIG. 2 is a sectional view of the door seal structure constituting the principal part of the microwave oven of FIG. 1;
  • FIG. 3 is a sectional view of the insulating coating constituting the principal part of FIG. 2;
  • FIG. 4 is a sectional view showing another embodiment of the door seal structure shown in FIG. 2.
  • numeral 1 designates an oven housing having a heating cavity formed therein and the microwave energy is radiated into the heating cavity from a high frequency source.
  • Numeral 2 designates a frame-type door pivotally mounted opposite to the opening of the heating cavity. The door 2 is provided with an aluminum plate 3 covering its inner surface and forming with the door 2 a choke cavity 4 which is opened at one end. The dimensions a and b of the choke cavity 4, as shown in FIG. 2, are selected at a quarter wavelength.
  • Numeral 5 designates a stainless steel flange mounted around the opening of the heating cavity so that the flange is pressed against the outer surface of the aluminum plate 3 when the door 2 is closed.
  • Numeral 6 designates an aluminum sash attached to the stainless steel flange 5 with a microwave absorbing substance such as a rubber 7 mixed with manganese or nickel ferrite material filled in the inner part thereof.
  • the microwave absorbing substance 7 is mechanically brittle and tends to be easily broken and for this reason its surface is protected by a cover 8 composed of a low dielectric constant material such as polypropylene so as to prevent food from sticking to the microwave absorbing substance 7 and reducing its absorbing effect in the long periods of use.
  • a cover 8 composed of a low dielectric constant material such as polypropylene so as to prevent food from sticking to the microwave absorbing substance 7 and reducing its absorbing effect in the long periods of use.
  • a cover 8 composed of a low dielectric constant material such as polypropylene so as to prevent food from sticking to the microwave absorbing substance 7 and reducing its absorbing effect in the long periods of use.
  • a cover 8 composed of a low dielectric constant material such as polypropylene so as to prevent food from sticking
  • the aluminum plate 3 and the stainless steel flange 5 held together closely prevent the escape of microwave energy to the outside, while a choke attenuator is formed by the chokes a and b so that even if there is an opening left between the plate 3 and the flangeS, the wave is attenuated by the choke attenuator.
  • the thus attenuated wave is then absorbed by the succeeding microwave absorbing substance 7 preventing the escape of microwave energy and thus ensuring a complete seal.
  • the microwave absorbing substance 7 is disposed substantially parallel to the direction in which the door 2 is opened, even if the door 2 is opened slightly, the distance c remains unchanged thus ensuring a satisfactory absorbing effect.
  • the substance 7 is not contaminated by food and the like keeping it clean and at the same time providing an excellent external appearance.
  • the provision of the insulating coating 9 between the aluminum plate 3 and the flange 5 prevents the danger of burning by spark discharge.
  • the seals for the door 2 do not require any mechanical contact between the plate 3 and the flange 5, there is no need to forcibly close the door, but only a little strength is required and thus it is easy to handle.
  • FIG. 3 there is shown a modified form of the insulating coating consisting of an anodically formed oxide coating whose insulating property is satisfactory for its thickness.
  • an anodic oxidation coating is deposited on the surface of a metal substrate and then an insulating material 11 is filled into a large number of small holes in the anodized surface. This ensures a satisfactory insulating property meeting the requirements with athin film of oxide; with the resultant improvement in the efficiency of surface treatment and a reduction in the manufacturing cost.
  • FIG. 4 illustrates another embodiment of the invention in which an'insulating coatingl2 is deposited on the heating cavity side with the equivalent effect as that of the FIG. 1 embodiment in which the insulating coating is' formed on the door side.
  • the escape of microwave energy is prevented by the provision of close contact between the door and the front opening portion of the heating cavity, while a choke attenuator is provided by the chokes to take care of the wave escaping through I a gap left between the door and the heating cavity opening by a spoon, for example, which is inadvertently caught therebetween.
  • the wavethus attenuated is then absorbed by'the succeeding microwave absorbing substance.
  • the present. invention provides an improved structure which effectively prevents the escape of microwave energy and which also serves as a fail safe.
  • a microwave oven comprising:
  • a housing formed with a heating cavity having a" to said heating cavity from escaping therethrough
  • said capacitive seal being formed between the surfaces of said door and said housing which are placed in contact with each other when said door is closed in a portion adjacent to the periphery of said first opening of said heating cavity, said door being formed with a choke cavity having a second opening for attenuating escaped microwave energy traveling from said heating cavity through said capacitive seal when said door is slightly open, said second opening facing the surface of said housing at the outside portion of the periphery of said capacitive seal when said door is closed;
  • a microwave absorbing material on at least one of the marginal side edge of said door and a portion of said housing opposing said marginal side edge of said door, said microwave absorbing'material being disposed substantially parallel to the direction in which said door'is opened, said capacitive seal, said choke cavity and said absorption material being in a series relationship in the direction of escaped microwave energy.
  • microwave oven according to claim 1 wherein said microwave absorbing material is composed'of a ferrite rubber mixed with manganese ferrite material.
  • said insulating coating comprises an anodically formed oxide coating.
  • said low dielectric constant material is composed of polypropylene.
  • a microwave oven according to claim 4, wherein said oxide coating is composed of anodized aluminum.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electric Ovens (AREA)
  • Constitution Of High-Frequency Heating (AREA)
US00244056A 1971-04-19 1972-04-14 Fail safe door seal microwave oven Expired - Lifetime US3803377A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46025561A JPS5127004B1 (de) 1971-04-19 1971-04-19

Publications (1)

Publication Number Publication Date
US3803377A true US3803377A (en) 1974-04-09

Family

ID=12169336

Family Applications (1)

Application Number Title Priority Date Filing Date
US00244056A Expired - Lifetime US3803377A (en) 1971-04-19 1972-04-14 Fail safe door seal microwave oven

Country Status (7)

Country Link
US (1) US3803377A (de)
JP (1) JPS5127004B1 (de)
CA (1) CA952590A (de)
DE (2) DE2218611C3 (de)
FR (1) FR2133848B1 (de)
GB (1) GB1392857A (de)
IT (1) IT952719B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3879595A (en) * 1973-01-08 1975-04-22 Tappan Co Microwave oven door seal
US3956608A (en) * 1971-10-19 1976-05-11 U.S. Philips Corporation Energy seal for a microwave oven
US4000390A (en) * 1975-02-14 1976-12-28 Hobart Corporation Microwave oven door
US4046983A (en) * 1975-09-03 1977-09-06 Tdk Electronics Co., Ltd. Microwave heating oven having seal means for preventing the leakage of microwave energy
US4059742A (en) * 1975-07-09 1977-11-22 Litton Systems, Inc. Microwave seal for combination cooking apparatus
US4166207A (en) * 1977-05-31 1979-08-28 Whirlpool Corporation Microwave generating device--door seal
FR2885004A1 (fr) * 2005-04-22 2006-10-27 Premark Feg Llc Four a micro-ondes avec un cache pour piege a ondes
CN100360854C (zh) * 2006-03-13 2008-01-09 王宝根 带微波吸收腔的微波炉门
CN100365344C (zh) * 2006-02-28 2008-01-30 王宝根 带微波吸收腔的新型微波炉

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2265311C2 (de) * 1972-09-08 1981-12-24 Podszuck Gmbh & Co Kg, 2300 Kiel Feuerschutztür mit einem Türblatt in selbsttragender Kastenkonstruktion
US4088024A (en) * 1976-05-17 1978-05-09 Litton Systems, Inc. Combination microwave-thermal oven thermostat
LU75867A1 (de) * 1976-09-24 1978-06-09
JPS5433910U (de) * 1977-08-08 1979-03-06
DE3106786A1 (de) * 1981-02-24 1982-09-09 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Mikrowellenerhitzungsgeraet
JPS5933793A (ja) * 1982-08-18 1984-02-23 松下電器産業株式会社 高周波加熱装置
JPS6173400A (ja) * 1984-09-18 1986-04-15 ティーディーケイ株式会社 電波吸収ガスケツト
DE3607557A1 (de) * 1986-03-07 1987-12-23 Bosch Siemens Hausgeraete Mikrowellenofen
EP2405204B1 (de) * 2010-07-09 2017-10-11 Electrolux Home Products Corporation N.V. Frontrahmen für einen Ofeninnenraum eines Backofens

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE99C (de) * 1877-07-13 R. VOGEL, Maschinenmeister, in Ibbenbüren Räderkuppelung für Gebirgslokomotiven
US3249731A (en) * 1963-11-14 1966-05-03 Westinghouse Electric Corp Oven
GB1013398A (en) * 1964-01-17 1965-12-15 Hirst Electronic Ltd Microwave food-heating apparatus
US3525841A (en) * 1968-11-04 1970-08-25 Litton Precision Prod Inc Door seal for microwave ovens
JPS5011108B1 (de) * 1970-03-03 1975-04-26
JPS5018181Y1 (de) * 1970-06-01 1975-06-04

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3956608A (en) * 1971-10-19 1976-05-11 U.S. Philips Corporation Energy seal for a microwave oven
US3879595A (en) * 1973-01-08 1975-04-22 Tappan Co Microwave oven door seal
US4000390A (en) * 1975-02-14 1976-12-28 Hobart Corporation Microwave oven door
US4059742A (en) * 1975-07-09 1977-11-22 Litton Systems, Inc. Microwave seal for combination cooking apparatus
US4046983A (en) * 1975-09-03 1977-09-06 Tdk Electronics Co., Ltd. Microwave heating oven having seal means for preventing the leakage of microwave energy
US4166207A (en) * 1977-05-31 1979-08-28 Whirlpool Corporation Microwave generating device--door seal
FR2885004A1 (fr) * 2005-04-22 2006-10-27 Premark Feg Llc Four a micro-ondes avec un cache pour piege a ondes
US20080149629A1 (en) * 2005-04-22 2008-06-26 Premark Feg L.L.C. Microwave Oven With a Mask For Wave Trap
CN100365344C (zh) * 2006-02-28 2008-01-30 王宝根 带微波吸收腔的新型微波炉
CN100360854C (zh) * 2006-03-13 2008-01-09 王宝根 带微波吸收腔的微波炉门

Also Published As

Publication number Publication date
JPS5127004B1 (de) 1976-08-10
CA952590A (en) 1974-08-06
DE2218611B2 (de) 1977-08-25
IT952719B (it) 1973-07-30
DE2218611C3 (de) 1978-04-27
FR2133848A1 (de) 1972-12-01
DE2265217C3 (de) 1978-06-29
DE2218611A1 (de) 1973-06-28
DE2265217B2 (de) 1977-11-10
FR2133848B1 (de) 1977-06-17
DE2265217A1 (de) 1976-12-16
GB1392857A (en) 1975-04-30

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