EP0270984A2 - Méthode de fabrication de fours de cuisson - Google Patents

Méthode de fabrication de fours de cuisson Download PDF

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Publication number
EP0270984A2
EP0270984A2 EP87117762A EP87117762A EP0270984A2 EP 0270984 A2 EP0270984 A2 EP 0270984A2 EP 87117762 A EP87117762 A EP 87117762A EP 87117762 A EP87117762 A EP 87117762A EP 0270984 A2 EP0270984 A2 EP 0270984A2
Authority
EP
European Patent Office
Prior art keywords
sheets
casing
box
shaped elements
edges
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.)
Withdrawn
Application number
EP87117762A
Other languages
German (de)
English (en)
Other versions
EP0270984A3 (fr
Inventor
Dino Bacci
Luigi Brunitto
Edi Zorzit
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.)
Zeltron Istituto Zanussi per la Ricerca SpA
Original Assignee
Zeltron Istituto Zanussi per la Ricerca 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 Zeltron Istituto Zanussi per la Ricerca SpA filed Critical Zeltron Istituto Zanussi per la Ricerca SpA
Publication of EP0270984A2 publication Critical patent/EP0270984A2/fr
Publication of EP0270984A3 publication Critical patent/EP0270984A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • F24C15/08—Foundations or supports plates; Legs or pillars; Casings; Wheels
    • 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
    • F24C15/34—Elements and arrangements for heat storage or insulation

Definitions

  • the present invention relates to a method for the manu­facture of appliances for cooking foods of any nature in an insulated enclosure (kitchen ovens, individually or in combination with a cooktop), the casing of such appli­ances being composed of walls, a bottom, and a door and provided with an adequate thermal insulation.
  • a provision for limiting the danger of contaminating the workplace environment with glass fibres consists in the application of a bonding agent to the fibres to thereby achieve a higher degree of compaction.
  • Described in US 2,164,143 is an alternative insulating structure, in particular for refrigerating appliances, obtained by the introduction of fine powders, such as metal oxides and Kieselguhr (diatomaceous earth) into a space formed between two flexible metal sheets by hermet­ically welding them to one another, and from which the air is subsequently evacuated.
  • fine powders such as metal oxides and Kieselguhr (diatomaceous earth)
  • the casing obtained according to the method of US 2,164,143 does not either permit the integration of functional components of the respective appliances (in the case considered by the present invention, resistance heaters, burners, a thermostat, a grill, a fan and the like).
  • the insulating structure of the casing is composed of evacuated anorganic powders filling the space between the outer walls and the interior compartment of the casing.
  • an insulation formed of evacuated anorganic powders is also capable of withstanding the high temperatures generated within the oven chamber, offering better thermal insulation characteristics than glass wool and permitting the manufacturing process to be completely automatized.
  • a main object of the invention is thus the provision of an applicance for cooking foods, provided with an insulating structure on the base of evacuated anorganic powders of high efficiency and obtainable by an automatized process.
  • the invention thus provides a method for the manufacture of cooking ovens, particularly of the domestic type, comprising a casing the metal sheet walls of which contain a thermal insulation formed of a mass of evacuated anorg­anic powders and are provided with a plurality of funct­ional components such as burners, electric resistance heaters, a thermostat, a fan and the like.
  • this method is characterized by comprising a first step of cutting and drilling two planar sheets having the developed shapes respectively of the complete internal and external walls of the oven, and of mounting the respective functional components on said sheets, a second step of bending and welding said sheets to form two component-equipped box-shaped elements having one open side, a third step of inserting the box-shaped elements into one another and welding them along their edges to form an empty space therebetween, and finally a fourth step of completely filling said empty space with an anorganic powder, and evacuating and hermetically sealing said space.
  • the insulating materials employed according to the invent­ion are preferably expanded perlite or diatomaceous earth.
  • thermal conductivity of these materials is known to decrease still further under vacuum conditions: at 0.01 mm Hg the conductivity has decreased to about one tenth.
  • thermal insulation obtainable with these conductivity values is conducive to a considerable improvement of the performance of the oven when the thickness of the insulat­ ing walls remains the same as at present, or to an increase of the available free volume when the thickness of the walls is reduced to dimensions for obtaining the same performance as in a conventional oven. In any case there results a noticable energy saving effect.
  • a further advantage obtained by the employ of perlite or diatomaceous earth derives from the fact that the insul­ation remains constant over long time: there is no degrad­ation of the insulating material by the action of high temperatures, and thus no change in the insulating capacity.
  • the influence of temperature on the thermal conductivity is less then in the case of glass wool: as a matter of fact, the thermal conductivity is much less responsive to rising temperatures and is not noticeably increased thereby.
  • the sealing of the powders between two metallic walls also ensures impermeability to external agents (air), so that it is not necessary to introduce absorbent substances (getters) for the prevention of a gradual rising of the internal pressure with the resultant degradation of the performance of the applicance.
  • the conventional process for the manufacture of an oven usually involves the formation of the interior walls and the bottom by suitably stamping metal sheets. These two components are formed with perforations for the introduct­ion8 of the necessary functional components into the oven chamber, and welded together to form a unitary body. After this body has been enamelled, the glass wool is applied to the outer surfaces of the assembled casing.
  • the method according to the invention comprises a first step in which an integral piece 12 having the developed shape of the complete outer walls of the overn (fig. 1) and another integral piece 13 having the developed shape of the complete inner walls of the oven (fig. 2) are cut from a metal sheet.
  • piece 12 has to be suitably greater than those of piece 13, because the two box-shaped elements to be formed of these pieces are to be interconnected in a manner leaving an empty space therebetween to be sub­sequently filled with insulating powders as will become evident as the description proceeds.
  • each of the two pieces is provided with necessary perforations 14-16 for mounting the functional components (e.g. resistance heater, thermostat etc.) of the appliance (fig.2).
  • functional components e.g. resistance heater, thermostat etc.
  • the perforations formed in the external and internal walls are interconnected by connecting pipes welded thereto at their ends to thereby ensure the hermetical sealing of the vacuum to be subsequently created in the intervening space.
  • the lateral walls of the inner casing are additionally formed with elongate projections 17 to act as rails for supporting grids and shelves within the oven (fig. 3).
  • the method according to the invention includes the further step of bending the two metal sheet pieces and of welding them along abutting edges to thereby form two box-shaped elements 18, 19 each having an open side (fig.4).
  • the element having the smaller dimensions is then inserted into the other one so as to create an empty space between the two elements.
  • the two elements are welded together along their respective edges. These edges should be formed with zones of different mechanical strength for compensating the shrinkage of the powders during the evacuation of the intervening space between the two elements in the subsequent processing phase.
  • the welding step is preferably carried out in a continuous laser welding oper­ation.
  • the oven may if need be also be subjected to an enamelling process.
  • the intervening empty space is then filled with anorganic powders and subsequently evacuated.
  • the outer casing is provided with passages which are sub­sequently closed by electric welding after the introduct­ion of the powders and the evacuation of the intervening space. The compaction of the powders within the intervening space is ensured by vibrating the casing with the aid of a vibrating table whereon it is placed.
  • the described method for making the oven is also applied to the manufacture of the door, which also consists of an inner and an outer sheet metal wall sealingly welded together and filled with an evacuated powder.
  • the proposed method offers the following advantages: - an improvement of the insulating performance relative to that of glass wool for the same wall thickness, or a corresponding reduction of the wall thickness, and thus of the overall dimensions, for the same insulating performance; - substantially constant thermal conductivity of the insulation with rising temperatures; - complete impermeability of the walls, whereby the employ of absorbent substances is rendered unnecessary and the thermal insulating characteristics are maintained over an extended period of time; - a major degree of automatization of the manufacturing process, resulting in greater reliability and reduced physical contact with operating personnel; the manufact­uring process is thereby rendered less noxious to the environment of the workplace.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Baking, Grill, Roasting (AREA)
  • Refrigerator Housings (AREA)
  • General Preparation And Processing Of Foods (AREA)
EP87117762A 1986-12-11 1987-12-01 Méthode de fabrication de fours de cuisson Withdrawn EP0270984A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT4575786 1986-12-11
IT45757/86A IT1201785B (it) 1986-12-11 1986-12-11 Procedimento per la fabbricazione di forni di cottura

Publications (2)

Publication Number Publication Date
EP0270984A2 true EP0270984A2 (fr) 1988-06-15
EP0270984A3 EP0270984A3 (fr) 1989-10-04

Family

ID=11258090

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87117762A Withdrawn EP0270984A3 (fr) 1986-12-11 1987-12-01 Méthode de fabrication de fours de cuisson

Country Status (3)

Country Link
EP (1) EP0270984A3 (fr)
JP (1) JPS63217152A (fr)
IT (1) IT1201785B (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0385675A1 (fr) * 1989-02-27 1990-09-05 Electrolux Limited Boîtiers tubulaires
DE4028743A1 (de) * 1990-09-11 1992-03-12 Miele & Cie Backofen mit einer backmuffel
DE4210799A1 (de) * 1992-04-01 1993-10-07 Kulmbacher Klimageraete Heizgerät, insbesondere elektrisches Speicherheizgerät
US5763857A (en) * 1994-06-27 1998-06-09 Bosch-Siemens Hausgeraete Gmbh Heating home appliance
DE19519409C2 (de) * 1995-05-26 2001-03-01 Aeg Hausgeraete Gmbh Back- und Bratofenmuffel
EP1541930A1 (fr) * 2003-12-09 2005-06-15 Samsung Electronics Co., Ltd. Four à vapeur avec boítier intérieur comprenant un vide
EP1628078A1 (fr) * 2004-08-19 2006-02-22 Samsung Electronics Co., Ltd. Cuiseur à vapeur surchauffée
WO2018067125A1 (fr) * 2016-10-04 2018-04-12 Whirlpool Corporation Cavité super-isolée pour haute température pour applications de cuisson

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1839469A (en) * 1928-08-04 1932-01-05 Moore Brothers Co Stove construction
US2164143A (en) * 1934-11-10 1939-06-27 Termisk Isolation Ab Insulation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1839469A (en) * 1928-08-04 1932-01-05 Moore Brothers Co Stove construction
US2164143A (en) * 1934-11-10 1939-06-27 Termisk Isolation Ab Insulation

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WELDING AND METAL FABRICATION. vol. 54, no. 7, October 1986, HAYWARDS HEATH GB page 314 - 315; "Microwave Oven Production" *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0385675A1 (fr) * 1989-02-27 1990-09-05 Electrolux Limited Boîtiers tubulaires
DE4028743A1 (de) * 1990-09-11 1992-03-12 Miele & Cie Backofen mit einer backmuffel
DE4210799A1 (de) * 1992-04-01 1993-10-07 Kulmbacher Klimageraete Heizgerät, insbesondere elektrisches Speicherheizgerät
US5763857A (en) * 1994-06-27 1998-06-09 Bosch-Siemens Hausgeraete Gmbh Heating home appliance
DE19519409C2 (de) * 1995-05-26 2001-03-01 Aeg Hausgeraete Gmbh Back- und Bratofenmuffel
EP1541930A1 (fr) * 2003-12-09 2005-06-15 Samsung Electronics Co., Ltd. Four à vapeur avec boítier intérieur comprenant un vide
EP1628078A1 (fr) * 2004-08-19 2006-02-22 Samsung Electronics Co., Ltd. Cuiseur à vapeur surchauffée
WO2018067125A1 (fr) * 2016-10-04 2018-04-12 Whirlpool Corporation Cavité super-isolée pour haute température pour applications de cuisson
US11287142B2 (en) 2016-10-04 2022-03-29 Whirlpool Corporation High temperature super insulated cavity for cooking applications

Also Published As

Publication number Publication date
IT8645757A0 (it) 1986-12-11
JPS63217152A (ja) 1988-09-09
IT1201785B (it) 1989-02-02
EP0270984A3 (fr) 1989-10-04

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