EP0374520A1 - Four à micro-ondes équipé en option d'un élément chauffant à résistance - Google Patents

Four à micro-ondes équipé en option d'un élément chauffant à résistance Download PDF

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Publication number
EP0374520A1
EP0374520A1 EP89121703A EP89121703A EP0374520A1 EP 0374520 A1 EP0374520 A1 EP 0374520A1 EP 89121703 A EP89121703 A EP 89121703A EP 89121703 A EP89121703 A EP 89121703A EP 0374520 A1 EP0374520 A1 EP 0374520A1
Authority
EP
European Patent Office
Prior art keywords
cavity
space
frame
oven
edge
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.)
Ceased
Application number
EP89121703A
Other languages
German (de)
English (en)
Inventor
Flavio Gatta
Arturo Negretti
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.)
Industrie Zanussi SpA
Original Assignee
Industrie Zanussi SpA
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 Industrie Zanussi SpA filed Critical Industrie Zanussi SpA
Publication of EP0374520A1 publication Critical patent/EP0374520A1/fr
Ceased 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

Definitions

  • the present invention relates to a microwave oven optionally also having thermal operation and equipped with a means for shielding high frequency electromagnetic radiation (RF).
  • RF high frequency electromagnetic radiation
  • microwave ovens cook food using high frequency electromagnetic waves (2450 MHz) generated by an emitter valve, called a “magnetron”, which converts electrical energy into electromagnetic energy.
  • the waves are conveyed by the magnetron inside the cooking cavity made of metal or another thermally and electrically conductive material into which the food to be treated (thawed, cooked, reheated) has been introduced.
  • part of the electromagnetic energy is not immediately ab­sorbed but is reflected repeatedly by the walls of the cavity in order to penetrate the food from all directions so as to heat the food as evenly as possible.
  • the radiation may spread through the openings and thus be emitted to the outside.
  • the known technology in this sector has been developed with consideration of a particular feature of ovens using exclusively the microwave cooking method. That is, the cavity and the front metal frame surrounding the entrance to the cavity are closely linked (and sometimes made of the same piece of sheet metal or steel) so that it is not possible for radiation to escape between these two parts of the oven since they are at the same electrical potential.
  • thermal ovens particularly for domestic use, that have the cavity proper separate from other parts of the oven; in particular there is a space left between the cavity and the peripheral frame surrounding the entire entrance to the oven and functioning as an abutment for the inside part of the door.
  • This space is to create a thermal "jump" between the inside wall of the cavity and the frame so as to increase the thermal insulation of the cavity, thereby increasing its power efficiency, perform­ance and safety.
  • the space is usually occupied by a rubber seal (with special features). Even if of small thickness, it interrupts the thermal flow of conduction from the interior of the cavity toward the frame, and thus toward the outside of the oven.
  • the rubber seal is utilized also to constitute a bar­rier (with its protruding part toward the outside and in abutment with the inside face of the door when the latter is closed) for the passage of hot air from the inside of the oven to the outside.
  • this solution presents the great problem that the door must be completely redesigned, which involves high investments and also sig­nificantly increases the production costs of the oven. Furthermore, this known solution has the disadvantages of making the door heavier (result­ing in greater stress on the hinges) and reducing the inside volume that can be utilized in the oven.
  • the present invention is intended to realize a means for shielding the microwave radiation in an oven having a space, and thus a difference in electrical potential, between the cavity and the frame surrounding the entrance to the oven.
  • This means substantially comprises a strip of metal material formed in a U shape in cross section and bent into a substantially rectangular ring having dimensions and a shape similar to the outside transverse periphery of the cavity, and with the open part of the U turned toward the plane of the ring.
  • This means is mounted about the cavity in its front zone so that the U appears exactly in correspondence with the above-described space.
  • oven 1 with open front door 2, frame 3 surrounding the entrance to the cavity, inside wall 4 of the cav­ity of the oven, edge 5 delimiting the inside wall of the frame and rubber seal 6 interposed between edge 5 and inside wall 4 along the entire pe­riphery of edge 5.
  • the four corners of the means have notches along the front edge so as to permit an easy and regular bending of the corner without overstressing and without curling of the front edge.
  • This Fig. 3 illustrates means 8 which hermetically seals space 7 (in terms of the escape of radiation), its flat end 9 lying adjacent the wall of cavity 4 and its other flat end 10 adjacent the front frame.
  • Fig. 4 one can see the assembly plan of closed rectan­gular ring-shaped means 8 about the cavity and closely fitting frame 3.
  • means 8 has in each of its cor­ners a series of notches 15 for permitting means 8 to be bent at right angles.
  • Figs. 6a, 6b, 6c and 6d show schematic views of four constructional variations of the described means. They differ in that ends 9 and 10 are differently bent and realized on different profiles of means 8, that none­theless fall within the scope of the invention.
  • Means 8 when installed in the oven as illustrated in the above figures creates a completely closed annular chamber 14 (see Fig. 3) about space 7 since sides 9 and 10 of means 8 closely fit the corresponding flat parts of the oven and thus do not permit any passage of radiation.
  • space 7 can be disposed on the outside face.
  • constructional modifica­tions should be obvious that are necessary for realizing a means that closes the passage of radiation and thus falls within the scope of protec­tion of the present patent.
  • the means can be obtained by different techniques - cutting, bending, welding of various pieces, etc. - evidently without going beyond the scope of the invention.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electric Ovens (AREA)
EP89121703A 1988-12-19 1989-11-24 Four à micro-ondes équipé en option d'un élément chauffant à résistance Ceased EP0374520A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT4577288 1988-12-19
IT8845772A IT1225856B (it) 1988-12-19 1988-12-19 Forno a microonde dotato di dispositivo per la schermatura delle microonde

Publications (1)

Publication Number Publication Date
EP0374520A1 true EP0374520A1 (fr) 1990-06-27

Family

ID=11258142

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89121703A Ceased EP0374520A1 (fr) 1988-12-19 1989-11-24 Four à micro-ondes équipé en option d'un élément chauffant à résistance

Country Status (2)

Country Link
EP (1) EP0374520A1 (fr)
IT (1) IT1225856B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2950617A1 (fr) * 2014-05-28 2015-12-02 Rational Aktiengesellschaft Appareil de cuisson doté d'un piège à micro-ondes
WO2016083070A1 (fr) * 2014-11-25 2016-06-02 BSH Hausgeräte GmbH Appareil ménager de cuisson

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3748424A (en) * 1972-08-07 1973-07-24 Gen Electric Built-in leakage radiation detecting device for a microwave oven
DE2622363A1 (de) * 1975-05-20 1976-12-02 Matsushita Electric Ind Co Ltd Mikrowellenofen mit tuerabschirmung
US4081647A (en) * 1976-05-10 1978-03-28 Roper Corporation Energy seal for a microwave oven

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3748424A (en) * 1972-08-07 1973-07-24 Gen Electric Built-in leakage radiation detecting device for a microwave oven
DE2622363A1 (de) * 1975-05-20 1976-12-02 Matsushita Electric Ind Co Ltd Mikrowellenofen mit tuerabschirmung
US4081647A (en) * 1976-05-10 1978-03-28 Roper Corporation Energy seal for a microwave oven

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2950617A1 (fr) * 2014-05-28 2015-12-02 Rational Aktiengesellschaft Appareil de cuisson doté d'un piège à micro-ondes
WO2016083070A1 (fr) * 2014-11-25 2016-06-02 BSH Hausgeräte GmbH Appareil ménager de cuisson

Also Published As

Publication number Publication date
IT1225856B (it) 1990-12-07
IT8845772A0 (it) 1988-12-19

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