Domestic oven and fan impeller for domestic oven

Abstract

A domestic oven including a cavity defining a cooking chamber and having a front opening that is closable by a door, a heating energy source for supplying heating energy to the cooking chamber, an air inlet different from the front opening that enables entering of ambient air into the cooking chamber, and an air outlet different from the front opening and from the air inlet that enables air or an air-gas-mixture or an air-gas-steam mixture present in the cooking chamber to leave the cooking chamber.

1 . A domestic oven, comprising:
 a cavity defining a cooking chamber and having a front opening that is closable by a door for charging and discharging food to be cooked into the cooking chamber;   a heating energy source for supplying heating energy to the cooking chamber;   an air inlet different from the front opening that enables entering of ambient air into the cooking chamber; and   an air outlet different from the front opening and from the air inlet that enables air or an air-gas-mixture or an air-gas-steam mixture present in the cooking chamber to leave the cooking chamber.   
     
     
         2 . The domestic oven according to  claim 1 , wherein the air inlet comprises a plurality of holes formed in a regular pattern arranged concentrically around an opening in a first cavity wall said opening being configured to receive a drive shaft for driving a fan impeller arrangeable or arranged inside of the cavity,
 and/or   wherein the air outlet comprises a plurality of holes formed in a regular pattern arranged in a second cavity wall adjacent to a front end of the cavity.   
     
     
         3 . The domestic oven according to  claim 2 , further comprising:
 an air inlet duct element that is attached to an exterior side of the first cavity wall in which the plurality of holes of the air inlet are provided, wherein the air inlet duct element forms an air inlet duct for guiding ambient air to the plurality of holes of the air inlet,   and/or   an air outlet duct element that is attached to an exterior surface of the second cavity wall in which the plurality of holes of the air outlet are provided, wherein the air outlet duct element forms an air outlet duct for guiding an air-gas-mixture or an air-gas-steam mixture leaving the plurality of holes of the air outlet away from the second cavity wall.   
     
     
         4 . The domestic oven according to  claim 3 , wherein a size of a passage formed by the air inlet is controllable by an air inlet valve configured to partially and/or fully open and/or to partially and/or fully close the passage formed by the air inlet duct and/or formed by the plurality of holes of the air inlet,
 and/or   wherein a size of a passage formed by the air outlet is controllable by an air outlet valve configured to partially and/or fully open and/or to partially and/or fully close the passage formed by the air outlet duct and/or formed by the plurality of holes of the air outlet.   
     
     
         5 . The domestic oven according to  claim 4 , wherein the air inlet valve comprises a first valve element that is configured to partially and/or fully open and/or to partially and/or fully close the passage formed by the air inlet duct, wherein the air inlet forms an outlet of the air inlet duct
 and/or   wherein the air outlet valve comprises a second valve element that is configured to partially and/or fully open and/or to partially and/or fully close the passage formed by the air outlet duct, wherein the air outlet forms an inlet of the air outlet duct.   
     
     
         6 . The domestic oven according to  claim 4 , wherein the air inlet duct element forms a shaft passage for the drive shaft, said shaft passage permitting the drive shaft to extend straight through the passage of the air inlet duct element and through the opening in the first cavity wall for receiving the drive shaft and wherein the air inlet duct element forms the air inlet duct passing from a first air inlet duct opening being offset from the shaft passage to a second air inlet duct opening being arranged around the shaft passage and being connected in flow communication with the plurality of holes of the air inlet around the opening for receiving the drive shaft in the first cavity wall. 
     
     
         7 . The domestic oven according to  claim 1 , further comprising at least one microwave heating source and/or at least one steam heating source and/or at least one radiation heating source, said air inlet and said air outlet being controllable such that:
 the domestic oven is configured to substantially close the air inlet and to partially open the air outlet while the domestic oven carries out a function to generate steam and/or to supply steam to the cooking chamber in order to perform a steam cooking process within the cooking chamber,   and/or   the domestic oven is configured to substantially fully open the air inlet and to substantially fully open the air outlet while the domestic oven carries out a function to remove steam that has been generated and/or supplied to the cooking chamber in order to perform a steam cooking process within the cooking chamber,   and/or   the domestic oven is configured to fully open the air inlet and to fully open the air outlet while the domestic oven removes moist air that is or has been generated while the domestic oven performs a microwave cooking process,   and/or   the domestic oven is configured to fully open the air inlet and to fully open the air outlet while the domestic oven removes moist air that is or has been generated while the domestic oven performs a drying process using the microwave heating source and/or the radiation heating source,   and/or   the domestic oven is configured to periodically open and close the air inlet and/or the air outlet while the domestic oven performs a cooking process using the radiation heating source.   
     
     
         8 . The domestic oven according to  claim 1 , further comprising a convection fan including a fan impeller being arranged within the cavity at a cavity wall and adjacent to the air inlet, wherein the convection fan is configured to draw ambient air through the air inlet into the cavity. 
     
     
         9 . The domestic oven according to  claim 8 , wherein the fan impeller includes an impeller body that comprises a first type of impeller blades on an impeller side facing the cooking chamber and a second type of impeller blades different from the first type on an impeller side facing the cavity wall, wherein the second type of impeller blades is configured to draw ambient air through the air inlet into the cavity. 
     
     
         10 . The domestic oven according to  claim 9 , wherein the cavity wall at which the fan impeller is arranged comprises an embossment extending towards an exterior side of the cavity and forming a clearance space on an interior side of the cavity, wherein the clearance space has such a shape that the second type of impeller blades can be arranged within the clearance space or adjacent thereto and at a close distance to the cavity wall such that an under pressure can be or is generated within the clearance space by the fan impeller during operation,
 and/or   wherein the embossment has such a shape that it prevents or hinders the drawn in ambient air to flow in a vertical direction and/or that it guides the drawn in ambient air in a lateral direction.   
     
     
         11 . A fan impeller defining an axis of rotation and comprising a backing plate and a plurality of fan blades being attached to the backing plate, wherein the backing plate is formed as a substantially flat circular disc and wherein at least one or at least two or all of the plurality of fan blades comprise a first blade portion extending substantially from the backing plate and a second blade portion extending as a free end of the fan blade(s) from the first blade portion in an angle (α) such that the second blade portion extends non-parallel to a plane being drawn up perpendicular to the axis of rotation. 
     
     
         12 . The fan impeller according to  claim 11 , wherein the first blade portion and the second blade portion are planar and flat portions of the fan blades and wherein the angle (α) between the first blade portion and the second blade portion is in a range between 93° and 120°. 
     
     
         13 . The fan impeller according to  claim 11 , wherein each first blade portion defines an radially outermost tip of the fan blade to which it belongs, wherein the outermost tip defines a circle upon rotation of the fan impeller, wherein an imaginary tangent line to the circle, and touching the outermost tip, encloses an angle (β) with a main surface of the first blade portion, wherein the angle (β) is in a range between 85° and 45°. 
     
     
         14 . The fan impeller according to  claim 11 , wherein the fan impeller comprises main fan blades comprising the first and second blade portions and supplementary fan blades, wherein the supplementary fan blades are arranged on a side of the fan impeller that is opposite to a side of the fan impeller on which the main fan blades are arranged, wherein the supplementary fan blades are planar and flat fan blades and wherein the first blade portion of the main fan blades and the supplementary fan blades extend substantially the direction of rotation (R) of the fan impeller, and wherein main surfaces of the first blade portions and main surfaces of the supplementary fan blades are arranged non-parallel to each other. 
     
     
         15 . The domestic oven according to  claim 1 , further comprising a fan impeller defining an axis of rotation and comprising a backing plate and a plurality of fan blades being attached to the backing plate, wherein the backing plate is formed as a substantially flat circular disc and wherein at least one or at least two or all of the plurality of fan blades comprise a first blade portion extending substantially from the backing plate and a second blade portion extending as a free end of the fan blade(s) from the first blade portion in an angle (α) such that the second blade portion extends non-parallel to a plane being drawn up perpendicular to the axis of rotation. 
     
     
         16 . The domestic oven according to  claim 2 , wherein the first cavity wall is a rear wall of the cavity, and wherein the second cavity wall is a top wall of the cavity. 
     
     
         17 . The fan impeller according to  claim 12 , wherein each first blade portion defines a radially outermost tip of the fan blade to which it belongs, wherein the outermost tip defines a circle upon rotation of the fan impeller, wherein an imaginary tangent line to the circle, and touching the outermost tip, encloses an angle (β) with a main surface of the first blade portion, wherein the angle (β) is in the range between 85° and 45°. 
     
     
         18 . A domestic oven, comprising:
 a cavity having a top wall, a bottom wall, a rear wall, and opposing side walls that collectively define a cooking chamber, said cavity having a front opening that is closable by a door;   a heating energy source configured to supply heating energy to the cooking chamber;   a shaft opening formed in the rear wall;   an air inlet having a plurality of inlet holes formed in the rear wall and arranged concentrically around the shaft opening, said air inlet being configured to enable entering of ambient air into the cooking chamber;   an air outlet having a plurality of outlet holes formed in the top wall and adjacent to the front opening, said air outlet being configured to enable air present in the cooking chamber to leave the cooking chamber;   an air inlet duct attached to an exterior side of the rear wall, said air inlet duct defining an inlet passage configured to guide ambient air to the air inlet, said air inlet duct extending between a first air inlet duct opening and a second air inlet duct opening, said second air inlet duct opening being disposed at said plurality of inlet holes, wherein said first air inlet duct opening is offset from said second air inlet duct opening;   an air outlet duct attached to an exterior side of the top wall, said air outlet duct defining an outlet passage configured to guide air leaving the plurality of outlet holes away from the top wall;   an air inlet valve configured to selectively open and close the first air inlet duct opening by adjusting a position of a first valve element between a fully opened position and a fully closed position thereof;   an air outlet valve attached to the air outlet duct and configured to selectively open and close an outlet opening of the air outlet duct by adjusting a position of a second valve element between a fully opened position and a fully closed position thereof.   
     
     
         19 . The domestic oven of  claim 18 , further comprising:
 a fan impeller disposed within the cavity and having a backing plate and a plurality of fan blades attached to said backing plate, wherein the backing plate is a flat, circular disc, and wherein at least one fan blade of said plurality of fan blades has a first blade portion extending from the backing plate, and a second blade portion extending from an end of the first blade portion, distal from the backing plate, to a tip of the at least one fan blade, wherein a first angle between the first blade portion and the second blade portion is in a range between 93° and 120°; and   a drive shaft attached to the fan impeller, wherein the drive shaft extends from a drive unit, located outside of the cavity, through the shaft opening and to the fan impeller.   
     
     
         20 . The domestic oven of  claim 19 , wherein the first blade portion defines a radially outermost tip of the at least one fan blade, wherein the outermost tip defines a circle upon rotation of the fan impeller, wherein an imaginary tangent line to the circle, and touching the outermost tip, encloses a second angle with a main surface of the first blade portion, wherein said second angle is in a range between 85° and 45°.