Portable electric oven with fan and motor arrangement for improved heated air flow and motor cooling

• US 5,801,362 A
• Filed: 11/13/1995
• Issued: 09/01/1998
• Est. Priority Date: 01/14/1994
• Status: Expired due to Fees

• Current Assignee: Broilking Corporation
• Original Assignee: Hudson Standard Corporation
• Inventors: Pearlman, Wade, Pearlman, Theodore
• Primary Examiner(s): Leung, Philip H.
• Application Number:
  US08/555,894
• Time in Patent Office: 1,023 Days
• Field of Search: 219/400, 219/757, 126/21 A, 126/21 R, 99/474, 99/479, 99/476, 99/421 R, 99/421 H, 99/421 HV
• US Class Current: 219/400
• CPC Class Codes: A47J 37/0623 Small-size cooking ovens, i.e. defining an at least partially closed cooking cavity A47J37/0605 takes precedence
• CPC Class Codes: A47J 37/0641 with forced air circulation, e.g. air fryers
• CPC Class Codes: F24C 15/325 electrically-heated
• CPC Class Codes: F24C 7/087 of electric circuits regulating heat

Abstract

An electrically heated convection oven with built-in rotisserie for rotisserie roasting, baking, broiling, defrosting, and dehydrating foodstuff is characterized by the use of two motors. One for operating a fan which rotates within the heating chamber to create high velocity air flow throughout the heating chamber; the second one for rotating the rotisserie spit. The second motor is also utilized to drive a cooling fan that draws air over electronic controls to keep them safely cool. The electronic controls comprise a microcomputer which is pre-programmed to recognize input from a user and to process information from an air temperature sensor in the oven. The heating chamber features generously radiused, interior surfaces which from an integral, parabolic, reflective surface with substantial width for enhancing air flow, to increase air velocities and create evenness of heat within the heating chamber, thereby contributing to the performance of the oven.

Claims

1. An electrically heated convection oven for baking, rotisserie roasting, broiling, defrosting, and dehydrating a foodstuff, comprising:

a heating chamber surrounded by an outer housing, said heating chamber having a top wall, two side walls, a rear wall, and a bottom wall, said housing comprising a rear wall spaced from said rear wall of said chamber to form an air duct, two side walls and a front door configured to be a front wall of said heating chamber;

a second housing attached to the exterior of said rear wall of said housing;

a first electric motor positioned in said second housing comprising a shaft inserted through said rear wall of said heating chamber, said shaft carrying a first radial fan impeller rotatable inside and in front of said rear wall of said heating chamber for moving heated air in said chamber, and a second radial fan impeller on the back of said rear wall for circulating air for cooling said motor inside said second housing;

at least one electric heating element mounted inside said chamber and close to and along its top wall; and

a control circuit for operating said first electric motor and said at least one heating element;

wherein at least one of said rear wall, said top wall and said bottom wall of said heating chamber is curved along substantially the entire length thereof to create a parabolically deflective surface for minimizing resistance from the interior of said heating chamber to movement of said heated air by said first radial fan impeller, said deflective surface having an inner concave surface facing said first radial fan impeller for enhancing movement of said heated air, said heating chamber not including a heated element located adjacent to said first radial fan impeller.

2. A convection oven as claimed in claim 1, wherein said rear wall, said top wall and said bottom wall of said heating chamber are configured as a single, integrally formed surface characterized by radiuses and tolerances that define a substantially parabolic shape.

3. A convection oven as claimed in claim 1, further comprising a control panel mounted on the exterior of said housing comprising instruments and a display device for activating said electronic control circuit to select different operations of said oven.

4. A convection oven as claimed in claims 3, wherein said electronic control circuit comprises a programmable microcomputer programmed to follow a user'"'"'s instructions relating to at least one of different modes of heating of food placed into said oven as selected by means of said control panel.

5. A convection oven as claimed in claim 4, wherein a temperature sensor is provided in said chamber and configured to transmit signals indicating the temperature inside said chamber to said microcomputer, and said microcomputer being programmed to adjust the temperature by controlling said at least one heating element.

6. A convection oven as claimed in claim 1, wherein said at least one heating element is a resistive rod extending along the longitudinal axis of said chamber and mounted in insulating members in said side walls of said chamber.

7. A convection oven as claimed in claim 1, wherein said side walls of said chamber are each provided with at least one inwardly projecting member for supporting a shelf member substantially horizontally therebetween.

8. A convection oven as claimed in claim 1, wherein a removable screen is detachably mounted to said rear wall in front of said first radial impeller in said chamber.

9. A convection oven as claimed in claim 1, wherein said first electric motor is speed-controllable inside said heating chamber in accordance with different modes of heating food.

10. A convection oven as claimed in claim 1, wherein said control circuit comprises a programmable logic device for controlling said first motor and said heating element in accordance with a plurality of different cooking modes.

11. The oven as defined in claim 1, wherein said hinged door closing the oven front contains a glass panel and a handle.

12. The oven as defined in claim 1, wherein said rear wall of said second housing is provided with air openings for drawing air outside said second housing for ventilation thereof and cooling of said first electric motor.

13. An electrically heated convection oven for baking, rotisserie roasting, broiling, defrosting, and dehydrating a foodstuff, comprising:

a heating chamber surrounded by an outer housing, said heating chamber having a top wall, two side walls, a rear wall, and a bottom wall, said housing comprising a rear wall spaced from said rear wall of said chamber to form an air duct, two side walls and a front door configured to be a front wall of said heating chamber, at least one of said side walls of said housing and said corresponding side wall of said chamber being spaced apart and configured to form a lateral compartment;

a second housing attached to the exterior of said rear wall of said housing;

a first electric motor positioned in said second housing comprising a shaft inserted through said rear wall of said heating chamber, said shaft carrying a first radial fan impeller rotatable inside and in front of said rear wall of said heating chamber for moving heated air in said chamber, and a second radial fan impeller on the back of said rear wall for circulating air for cooling said motor inside said second housing;

at least one electric heating element mounted inside said chamber and close to and along its top wall;

an electronic control circuit positioned in said lateral compartment for operating said first electric motor and said at least one heating element; and

a second electric motor positioned inside said lateral compartment, said motor having a high speed shaft inside said compartment carrying a third radial fan impeller for moving air to cool said electronic control circuit, and a reduction gear and a low speed shaft attached thereto which extends through said side wall of said chamber, said low speed shaft being configured for engagement with one end of a horizontal rotisserie spit to rotate said spit inside said chamber.

14. A convection oven as claimed in claim 13, further comprising a bearing attached to said side wall of said chamber that is opposite said side wall containing said low speed shaft, said bearing being adapted to carry the other end of said rotisserie spit.

15. A convection oven as claimed in claim 14, wherein said side wall attached to said bearing is spaced apart from the adjacent said side wall of said housing to form a second lateral compartment, said side wall of said housing and said side wall of said chamber each being configured with an aperture for receiving said spit therethrough, said bearing comprising a supporting member secured between said side walls to support and guide at least that portion of said spit extending through said second lateral compartment and through said apertures.

16. A convention oven as claimed in claim 15, wherein said apertures are generally elongated and extend from said front door toward said rear wall of said chamber and said housing, respectively, the end of each of said apertures in closest proximity to said rear wall being adapted to receive a tubular, concentric member secure to said spit and the remainder of said apertures being too narrow to accommodate the diameter of said tubular member.

17. A convection oven as claimed in claim 16, further comprising a movable door slidably secured to at least one of said side walls and adapted to reduce the flow of heated air from inside said chamber when said oven is operational to the exterior of said housing via said apertures.

18. An electrically heated convection oven for baking, rotisserie roasting, broiling, defrosting, and dehydrating a foodstuff, comprising:

a heating chamber surrounded by an outer housing, said heating chamber having a top wall, two side walls, a rear wall, and a bottom wall, said housing comprising a rear wall spaced from said rear wall of said chamber to form an air duct, two side walls and a front door configured to be a front wall of said heating chamber, at least one of said side walls of said housing and said corresponding side wall of said chamber being spaced apart and configured to form a lateral compartment;

a second housing attached to the exterior of said rear wall of said housing;

a first electric motor positioned in said second housing comprising a shaft inserted through said rear wall of said heating chamber, said shaft carrying a first radial fan impeller rotatable inside and in front of said rear wall of said heating chamber for moving heated air in said chamber, and a second radial fan impeller on the back of said rear wall for circulating air for cooling said motor inside said second housing;

at least one electric heating element mounted inside said chamber and close to and along its top wall;

an electronic control circuit positioned in said lateral compartment for operating said first electric motor and said at least one heating element; and

a second electric motor positioned inside said lateral compartment, said motor having a high speed shaft inside said compartment carrying a third radial fan impeller for moving air to cool said electronic control circuit, wherein said first lateral compartment comprises a shroud for enclosing said electronic control circuit and separating said electronic control circuit from the remaining portion of said lateral compartment comprising said third radial fan impeller, said housing comprising an aperture through which air from outside said housing enters said shroud, said shroud having an aperture for exuding the air into said remaining portion of said lateral compartment.

19. A convection oven as claimed in claim 18, wherein side wall of said housing corresponding to said first lateral compartment comprises at least one inlet aperture and at least one outlet aperture, said inlet aperture being operable to draw air from outside said housing toward said third radial fan impeller, said outlet aperture being operable to exude air from inside said lateral compartment to the outside of said housing.

20. A convection oven as claimed in claim 18, wherein side wall of said housing corresponding to said first lateral compartment comprises a plurality of elongated, substantially horizontally extending inlet slots, said inlet slots being arranged on said side wall so as to be in close proximity to said third radial fan impeller and being operable to draw air from outside said housing toward said third radial fan impeller.

21. A convection oven as claimed in claim 18, wherein side wall of said housing corresponding to said first lateral compartment comprises a plurality of elongated, substantially horizontally extending outlet slots, said outlet aperture being arranged at the top and bottom of said side wall operable to exude air from inside said lateral compartment and moved by said third radial fan impeller to the outside of said housing.

22. A convection oven as claimed in claim 18, wherein said electronic control circuit comprises a printed circuit board mounted in said shroud.

23. A convection oven as claimed in claim 18, wherein said housing comprises apertures and a molded, cylindrical member extending toward said third radial fan impeller through which air from outside said housing enters said apertures, said cylindrical member directing said air toward said third radial fan impeller.