EP0409324A1 - Four à air chaud - Google Patents

Four à air chaud Download PDF

Info

Publication number
EP0409324A1
EP0409324A1 EP90201891A EP90201891A EP0409324A1 EP 0409324 A1 EP0409324 A1 EP 0409324A1 EP 90201891 A EP90201891 A EP 90201891A EP 90201891 A EP90201891 A EP 90201891A EP 0409324 A1 EP0409324 A1 EP 0409324A1
Authority
EP
European Patent Office
Prior art keywords
impeller
oven
airflow
guiding means
heating elements
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Withdrawn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
EP90201891A
Other languages
German (de)
English (en)
Inventor
Mario Celegin
Johannes Arie Gijsbert Pieter Damsteegt
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.)
Whirlpool International BV
Original Assignee
Whirlpool International BV
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 Whirlpool International BV filed Critical Whirlpool International BV
Publication of EP0409324A1 publication Critical patent/EP0409324A1/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Withdrawn legal-status Critical Current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
    • F24C15/32—Arrangements of ducts for hot gases, e.g. in or around baking ovens
    • F24C15/322—Arrangements of ducts for hot gases, e.g. in or around baking ovens with forced circulation
    • F24C15/325—Arrangements of ducts for hot gases, e.g. in or around baking ovens with forced circulation electrically-heated

Definitions

  • the invention relates to a hot air oven having a oven cavity and an air heating space, the air heating space being located in connection to one of the walls of the oven cavity and comprising a driven impeller, airflow guiding means, heating elements and apertures to the oven cavity, the impeller sucking in air from the oven cavity in its center and blowing out the air with a radial and a tangential direction component towards the airflow guiding means and the heating elements and back to the oven cavity through apertures of the oven cavity.
  • the invention is also intended to include ovens of the so called combination type, for example a hot air oven combined with a microwave oven.
  • a hot air oven according to the above is previously known from for example EP 0152571.
  • the impeller is located on the top side of the oven cavity. Such a location of the impeller causes a very non-uniform heat distribution in the oven cavity.
  • an oven plate divides a cavity into two sections. The heated air from the upper section of the cavity then has difficulties to pass to the lower cavity section.
  • airflow guiding means are located between the impeller and the heating elements in the above prior art ovens.
  • the ovens have the disadvantage that the airflow having a suppressed tangential direction component leaving the airflow guiding means are disturbed by the following heating elements. This results in that the airflow blowing into the oven still contains airflow direction components causing an ununiform temperature distribution.
  • Another reason for the nonequal heating in the prior art oven is bad heat transfer from the heating element to the airflowing past the heating elements due to the small surface of the heating elements relative to the power and relieving phenomena when the air leaves the heating elements.
  • the bad heat transfer results in a high outer temperature on the heating elements which in its turn results in a high radiant efficiency to the cavity wall in connection to the air heating space.
  • This cavity wall is owing to that heated to high temperatures, which results in scorched parts of the load closest to said wall.
  • the present invention has for its object to provide a hot air oven which by the simple and cost-­advantageous construction provides a more uniform heating within the oven cavity.
  • the object of the invention is obtained by means of a hot air oven according to the first paragraph characterized in that the airflow guiding means are located on or beyond the heating elements viewed in a radial direction from the center of rotation of the impeller to suppress the tangential direction component.
  • the airflow guiding means suppress and may essentially eliminate the tangential velocity component of the airflow at the same time as they contribute to a better heat transfer from the heating elements resulting in a more uniform heating of the load.
  • radiation sheilds are located between the heating elements and the cavity wall in connection to the heating space and these radiation sheilds and the air­flow guiding means are integrated.
  • the embodiment is non-complicated and may be obtained to a low cost due to the fact that the radiation sheilds and the airflow guiding means may be manufactured starting from a metal plate by means of punching and bending.
  • Another advantage is that the air heating space in which the impeller and the heating elements are located together with the airflow guiding means and the radiation sheildings according to the invention may be made very compact and owing to that does not encroach on the total volume of the oven or the oven cavity in any decisive degree.
  • the hot air oven is characterized in that the airflow guiding means comprise an inlet section having an airflow direction essentially coinciding with the direction for the airflow from the impeller and an outlet section having an essentially radial airflow direction.
  • Inlet and outlet sections having the stated airflow directions causes a minimum of disturbances in the airflow delivered by the impeller simultaneously as the tangential direction component is efficiently supressed.
  • the oven comprises an oven cavity 2 and an air heating space 3 delimited by four vertical walls 4-7, an upper horizontal wall 8 and a lower horizontal wall 9.
  • the air heating space 3 and the oven cavity 2 are separated by a plate 10, preferably of metal.
  • An oven door 1 is located in the front wall of the horizontal walls 4.
  • a drive motor 11 is located to drive an impeller 12.
  • the drive motor 11 is separated from the impeller 12 by means of a wall 19.
  • Heating elements and airflow guiding means are located at the periphery of the impeller.
  • the heating element and airflow guiding means are only schematically indicated and has been given the reference numeral 13 in fig.
  • the plate 10 is shaped in such a way that apertures are formed between the oven cavity 2 and the air heating space 3. Apertures 14-17 and 18, respectively, are present both at the edges of the plate and in the center of the plate just opposite the impeller 12.
  • the impeller 12 sucks in air from the oven cavity through the aperture 18 in the center of the plate 10 towards the central part of the impeller.
  • the impeller 12 throws out the air with a radial and a tangential direction component from the center of the impeller and past the heating elements and airflow guiding means 13 located at the periphery of the impeller and back to the cavity 2 through apertures 14-17 at the edges of the plate 10.
  • the air flows through the oven are indicated by arrows 20.
  • FIGS 4 and 5 show an impeller having airflow guiding means according to a first embodiment.
  • the impeller 12 is provided with a suitable number of fan blades 21 and is coupled to a not in more detail shown drive motor shaft 22 in its center.
  • the drive motor 11 rotates the impeller 12 in the direction shown by the arrow 23.
  • the resulting velocity component that the airflow from the impeller 12 assumes is indicated by the arrow 24.
  • Guide rails 25 are located around the periphery of the impeller and fixed to a heating element 26 in order to reduce the tangential velocity component of the airflow from the impeller.
  • the guide rails are secured to a circular flat ring 28, preferably of a resilent material.
  • Each guide rail 25 has a recess 30 in order to at least partly clasp a heating element and is provided with an oblique edge 29.
  • the guide rails 25 may be mounted by pressing them over the heating element 26 so far that the recesses 30 in the guide rails at least partly grasp the heating element.
  • the oblique edge 29 on the guide rails 25 facilitates the applying of the guide rails by admitting a gradual deflection of the respective guide rails.
  • the arrows 31 indicates the airflow direction after the passage of the guiderails.
  • the shown flat ring 28 facilitates the mounting of the guide rails 25 but is not necessary and may possibly be removed after the mounting of the guiderails or totally spared in case of a more manual mounting.
  • the figures 6 and 7 show an impeller 12 having airflow guiding means and radiation shields according to a second embodiment of the invention.
  • Two heating elements 26, 27 are located around the impeller 12 having fan blades 21 adjacent to which airflow guiding means and radiation shields are located.
  • the heating elements are coupled to a connection plate in a suitable known way.
  • the two elements may, for example, consist of a loop having two turns.
  • the airflow guiding means and the radiation shields are made integrated starting from a metal blade. By means of punching and bending a circular ring has been manufactured having inwardly bent lugs 32 operating as radiation shields and essentially radially extending bendings 33 outwardly operating as guide rails.
  • the radiation shields are located in close connection to the plate 10 but on such a distance that a small airflow 34 may pass between the plate 10 and the radiation shields 32.
  • the construction increases the heat transfer from the heating elements 26, 27 to the circulating air in a considerable degree.
  • the bent lugs in 32 operate as radiation shields in order to decrease a direct radiation from the heating elements to the plate 10, that is the rear portion of the oven space.
  • the small airflow 34 which is admitted to pass between the plate 10 and the radiation shieldings of the ring keeps the heat transfer between the radiation shields of the ring and the plate 10 on a low level.
  • the figures 8-10 show a third embodiment of the invention.
  • a number of flanges 40 are applied around the heating element 26 surrounding the impeller 12.
  • the flanges 40 may be applied by means of welding, bracing or pressing.
  • the heating element is connected to a connection plate 41 which together with the heating element 26 establish an essentially circular loop.
  • the arrow 23 shows the rotation direction of the impeller 12 and the arrows 31 the direction for the airflow leaving the flanges 40.
  • the flange 40 consists of an essentially flat square-shaped plate having an aperture in the middle through which the heating element 26 runs.
  • the flange 40 is mounted on the heating element 26 in such way that the flat plate essentially coincides with the radial direction of the impeller 21. The airflow leaving the impeller will then enter between the flanges at a certain angle to the flange direction.
  • the inlet section 42 of the flanges may be adapted to the incoming airflow direction.
  • a flane is shown having such an inlet adapted to the airflow.
  • the flange 40 consists of a rectangular plate which is bent on the inlet side so that the inlet section 42 of the flange essentially coincides with the inlet direction of the airflow.
  • the outlet section 43 of the flange is as in the embodiment in fig. 9 directed to essentially coincide with a radial airflow.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Direct Air Heating By Heater Or Combustion Gas (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Furnace Details (AREA)
  • Electric Stoves And Ranges (AREA)
EP90201891A 1989-07-18 1990-07-12 Four à air chaud Withdrawn EP0409324A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8902557 1989-07-18
SE8902557A SE465739B (sv) 1989-07-18 1989-07-18 Eluppvaermd varmluftsugn, foersedd med anordningar foer styrning av luftfloedet kring ett flaekthjul

Publications (1)

Publication Number Publication Date
EP0409324A1 true EP0409324A1 (fr) 1991-01-23

Family

ID=20376562

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90201891A Withdrawn EP0409324A1 (fr) 1989-07-18 1990-07-12 Four à air chaud

Country Status (4)

Country Link
EP (1) EP0409324A1 (fr)
JP (1) JPH0331202U (fr)
CA (1) CA2021139A1 (fr)
SE (1) SE465739B (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0733862A1 (fr) * 1994-02-10 1996-09-25 Stoves Limited Perfectionnements apportés aux systèmes de brûleurs à combustible gazeuse et aux appareils comportant de tels systèmes
DE19957721A1 (de) * 1999-11-30 2001-05-31 Bsh Bosch Siemens Hausgeraete Backofen
EP1344986A1 (fr) * 2002-03-12 2003-09-17 Eurofours Four ventilé
WO2006000702A1 (fr) * 2004-06-14 2006-01-05 Seb S.A. Dispositif de chauffage d'un four a circulation d'air
WO2007020584A1 (fr) * 2005-08-12 2007-02-22 Arcelik Anonim Sirketi Dispositif de cuisson
WO2007138015A1 (fr) * 2006-05-26 2007-12-06 Arcelik Anonim Sirketi Four
WO2022051800A1 (fr) * 2020-09-09 2022-03-17 Breville Pty Limited Four

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3324844A (en) * 1965-11-09 1967-06-13 Vulcan Hart Corp Heat distribution system for gas-fired ovens
DE2339446B2 (de) * 1973-08-03 1977-07-14 Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart Umluftofen zum garen von lebensmitteln
DE2557867B2 (de) * 1975-12-22 1979-03-15 Bosch-Siemens Hausgeraete Gmbh, 7000 Stuttgart Umluftofen
GB2109920A (en) * 1981-10-02 1983-06-08 Victoria Gas & Fuel Corp Forced draught ovens
EP0152571A2 (fr) * 1984-01-20 1985-08-28 ZANUSSI GRANDI IMPIANTI S.p.A. Four à convection forcée
DE3517559A1 (de) * 1985-02-26 1986-11-20 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Back- und bratofen
EP0245618A2 (fr) * 1986-05-15 1987-11-19 Kabushiki Kaisha Toshiba Cuisinière à air circulé
EP0344743A2 (fr) * 1988-06-01 1989-12-06 ZANUSSI GRANDI IMPIANTI S.p.A. Cuisinière à gaz à circulation d'air

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3324844A (en) * 1965-11-09 1967-06-13 Vulcan Hart Corp Heat distribution system for gas-fired ovens
DE2339446B2 (de) * 1973-08-03 1977-07-14 Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart Umluftofen zum garen von lebensmitteln
DE2557867B2 (de) * 1975-12-22 1979-03-15 Bosch-Siemens Hausgeraete Gmbh, 7000 Stuttgart Umluftofen
GB2109920A (en) * 1981-10-02 1983-06-08 Victoria Gas & Fuel Corp Forced draught ovens
EP0152571A2 (fr) * 1984-01-20 1985-08-28 ZANUSSI GRANDI IMPIANTI S.p.A. Four à convection forcée
DE3517559A1 (de) * 1985-02-26 1986-11-20 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Back- und bratofen
EP0245618A2 (fr) * 1986-05-15 1987-11-19 Kabushiki Kaisha Toshiba Cuisinière à air circulé
EP0344743A2 (fr) * 1988-06-01 1989-12-06 ZANUSSI GRANDI IMPIANTI S.p.A. Cuisinière à gaz à circulation d'air

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0733862A1 (fr) * 1994-02-10 1996-09-25 Stoves Limited Perfectionnements apportés aux systèmes de brûleurs à combustible gazeuse et aux appareils comportant de tels systèmes
US5568803A (en) * 1994-02-10 1996-10-29 Brown; Geoffrey J. E. Relating to gaseous fuel burner assemblies and to appliances incorporating such burner assemblies
DE19957721A1 (de) * 1999-11-30 2001-05-31 Bsh Bosch Siemens Hausgeraete Backofen
EP1344986A1 (fr) * 2002-03-12 2003-09-17 Eurofours Four ventilé
FR2837067A1 (fr) * 2002-03-12 2003-09-19 Eurofours Sa Four ventile
WO2006000702A1 (fr) * 2004-06-14 2006-01-05 Seb S.A. Dispositif de chauffage d'un four a circulation d'air
WO2007020584A1 (fr) * 2005-08-12 2007-02-22 Arcelik Anonim Sirketi Dispositif de cuisson
WO2007138015A1 (fr) * 2006-05-26 2007-12-06 Arcelik Anonim Sirketi Four
WO2022051800A1 (fr) * 2020-09-09 2022-03-17 Breville Pty Limited Four

Also Published As

Publication number Publication date
SE8902557L (sv) 1991-01-19
JPH0331202U (fr) 1991-03-27
SE8902557D0 (sv) 1989-07-18
SE465739B (sv) 1991-10-21
CA2021139A1 (fr) 1991-01-19

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