Cooking appliance with a cooking chamber and fan wheel for a cooking appliance

Abstract

The invention relates to a cooking appliance (2) with a cooking chamber comprising a wall (4) with a fresh air opening (6) for introducing fresh air into the cooking chamber and a fan with a fan wheel (8) arranged on the cooking chamber side of the wall (4) for drawing fresh air through the fresh air opening (6) into the cooking chamber, wherein the fan wheel (8) has a base plate (10) arranged in front of the fresh air opening (6) and air conveying elements (22) arranged on the side of the base plate (10) facing away from the fresh air opening (6) and is rotatable about an imaginary axis of rotation extending perpendicular to the base plate (10), characterized in that the fan is designed as a reversible fan and, on the one hand, the respective dimensions and spatial configuration of the fresh air opening (6) and the fan wheel (8) and, on the other hand, the spatial arrangement of the fresh air opening (6) relative to the fan wheel (8) are designed to be coordinated with each other in such a way as tothat in both directions of rotation of the fan wheel (8), a sufficiently high negative pressure can be generated between the fresh air opening (6) and the base plate (10) of the fan wheel (8) in order to introduce fresh air into the cooking chamber through the fresh air opening (6) regardless of the direction of rotation. Furthermore, the invention relates to a fan wheel (8) for a cooking appliance (2) with a cooking chamber.

Description

[0001] The invention relates to a cooking appliance with a cooking chamber of the type mentioned in the preamble of claim 1 and a fan wheel for such a cooking appliance.

[0002] Such cooking appliances with a cooking chamber and fan wheels for cooking appliances are already known from the prior art in a multitude of embodiments, for example from publications EP 0 926 449 A1 and EP 3 726 930 B1. The known cooking appliances with a cooking chamber comprise a wall with a fresh air opening for introducing fresh air into the cooking chamber and a fan with a fan wheel arranged on the wall on the cooking chamber side for drawing the fresh air through the fresh air opening into the cooking chamber, wherein the fan wheel has a base plate arranged in front of the fresh air opening and air conveying elements arranged on the side of the base plate facing away from the fresh air opening and is rotatable about an imaginary axis of rotation extending perpendicular to the base plate.

[0003] The invention thus addresses the problem of improving a cooking appliance with a cooking chamber and a fan wheel for a cooking appliance with a cooking chamber.

[0004] According to the invention, this problem is solved by a cooking appliance with the features of claim 1. Advantageous embodiments and further developments of the invention are described in the following dependent claims.

[0005] The advantage achievable with the invention lies particularly in the improved design of a cooking appliance with a cooking chamber and a fan wheel for such an appliance. Due to the inventive design of the cooking appliance with a cooking chamber and the fan wheel for such an appliance, it is reliably ensured that a sufficiently high negative pressure can be generated between the fresh air inlet and the base plate of the fan wheel in both directions of rotation. This ensures that, regardless of the direction of rotation, the required quantity of fresh air is introduced into the cooking chamber through the fresh air inlet in every relevant operating condition of the cooking appliance. The fresh air inlet typically has a fresh air flap and serves, in particular, to regulate humidity in the cooking chamber. Depending on the humidity level and operating mode, i.e., operating condition, the fresh air flap is opened or closed, allowing fresh air to enter the cooking chamber or preventing it from doing so.The invention serves to generate sufficient negative pressure behind the fan wheel. The particular challenge lies in achieving a sufficiently high negative pressure in both directions of rotation. In addition to the optimal design of the fresh air inlet with the fresh air flap, it is also necessary to ensure the best possible air circulation through the cooking chamber using the fan wheel. This is also made possible by the invention. Furthermore, due to the design of the fan wheel according to the invention, a significant weight reduction is achieved compared to the prior art, while maintaining at least the same flow velocity of the fluid it conveys, thus substantially reducing the energy required to rotate the fan wheel.This is particularly advantageous for fan wheels according to the invention, which are designed as reversible fan wheels, i.e., fan wheels that can rotate in one direction or the other depending on the operating condition. The reduced rotating mass proves advantageous both when accelerating and decelerating the fan wheel according to the invention. Compared to the prior art, a weight reduction of up to 25% is achievable with the invention for the fan wheel according to the invention. Accordingly, it is possible to operate the fan wheel at a lower speed with the same performance, i.e., with comparable airflow velocities, in both the cooking appliance and the fan wheel according to the invention. The response of the fan wheel is also significantly improved when changing its direction of rotation due to the weight reduction.On the other hand, the fan wheel according to the invention can be manufactured in a very simple way in terms of design and production technology and also requires significantly less installation space than prior art fan wheels that have a comparable performance.

[0006] For this purpose, the fan is designed as a reversible fan, whereby on the one hand the respective dimensions and the respective spatial design of the fresh air opening and the fan wheel and on the other hand the spatial arrangement of the fresh air opening relative to the fan wheel are coordinated in such a way that in both directions of rotation of the fan wheel a sufficiently high negative pressure can be generated between the fresh air opening and the base plate of the fan wheel in order to introduce the required amount of fresh air into the cooking chamber through the fresh air opening in every relevant operating state of the cooking appliance, regardless of the direction of rotation.

[0007] In principle, the cooking appliance and the fan wheel according to the invention can be freely selected within wide suitable limits with regard to type, function, material, and dimensions. For example, the cooking appliance with the fan wheel according to the invention can be designed as a household appliance, such as a steam cooker. However, the invention can also be advantageously used with other cooking appliances with a cooking chamber. Furthermore, the invention is not limited to cooking appliances with a cooking chamber designed as household appliances. The invention can also be used with commercial appliances, i.e., cooking appliances for professional use. The term "fan wheel" is to be interpreted broadly, so that in addition to fans, blowers or the like are also included. The base plate with the blades is, for example, flat.

[0008] An advantageous embodiment of the cooking device according to the invention provides that the fresh air opening is designed as a circular opening with a clear cross-section of 27 mm and / or that the horizontal distance between the imaginary axis of rotation of the fan wheel and the center point of the fresh air opening, designed as a circular opening, is 48 mm, preferably that the aforementioned center point of the fresh air opening is arranged vertically offset by 10 mm relative to the imaginary axis of rotation of the fan wheel, and / or that a rear side of the base plate facing the fresh air opening has a distance of 16 mm from the fresh air opening. These parameters are highly relevant for the design of the cooking device according to the invention. They can be used individually or in any logical combination.

[0009] A further advantageous embodiment of the cooking appliance according to the invention provides that the fresh air opening and a shaft opening for a fan shaft for driving the fan wheel are arranged in a surface of the wall that is recessed from a base surface of the wall facing the cooking chamber, preferably that the recessed surface is bounded by two semicircular contours, wherein one semicircular contour is assigned to the fresh air opening and the other to the shaft opening, and the semicircular contours are connected on both sides by a straight contour, particularly preferably that the semicircular contours have a radius of 34 mm and the straight contours have a length of 18 mm and / or that the centers of circles corresponding to the semicircular contours have a horizontal distance of 18 mm and a vertical distance of 4 mm from each other, wherein the two centers of circles,The center point of the fresh air opening and the imaginary axis of rotation lie essentially on a common imaginary straight line. In this way, the cooking device according to the invention is designed in a particularly advantageous manner in terms of construction, manufacturing, and fluid dynamics. This applies especially to the preferred and, in particular, to the especially preferred embodiment of this further development.

[0010] An advantageous further development of the aforementioned further development of the cooking device according to the invention provides that the recessed surface is connected to the base surface by a circumferential connecting surface of the wall, and that the connecting surface forms an obtuse angle, preferably an angle of 135°, with the recessed surface. This further improves the design, manufacturing, and flow technology of the cooking device according to the invention in the relevant area. This applies particularly to the preferred embodiment of this further development.

[0011] A particularly advantageous embodiment of the cooking appliance according to the invention provides that the wall with the fresh air opening and the wave opening and the fan wheel are separated from the cooking chamber by an intermediate wall, wherein the intermediate wall has openings for the fresh air conveyed by the fan wheel. In this way, the aesthetics of the cooking appliance according to the invention are significantly improved, even when the cooking chamber is clearly visible.

[0012] As already explained above, the fan wheel according to the invention can be freely selected within wide suitable limits.

[0013] An advantageous further development of the fan wheel according to the invention provides that the fan wheel is designed as a one-piece sheet metal part, wherein the sheet metal part is simultaneously designed as a bent part for realizing the blades with the air conveying elements. This further simplifies the design and manufacturing.

[0014] A further advantageous embodiment of the fan wheel according to the invention provides that the fan wheel is designed as a one-piece sheet metal part, wherein the sheet metal part simultaneously serves as an embossed element for stiffening the central section and / or the blades. Preferably, the central section and the blades have a single, common embossing. Particularly preferably, this embossing has a circular annular contour that spatially separates the central section from the blades, with radial rib contours extending into the individual blades. In this way, the stiffness of the one-piece fan wheel according to the invention, required for robust and durable operation, is ensured in a simple manner despite its lightweight construction. With the preferred embodiment of this embodiment, this can be achieved with minimal manufacturing effort. This applies in particular to the especially preferred embodiment of this embodiment.The term "embossing" is to be interpreted broadly, so that all suitable types of deep drawing or the like are also included.

[0015] Another advantageous embodiment of the fan wheel according to the invention provides that the respective gap extends in a triangular shape from the corresponding free ends to the root of the gap, which is formed as the apex of the triangle. Preferably, this gap has an opening angle of 60° and / or a gap depth of 30 mm, measured from an imaginary circular path of the free ends to the root of the gap. This allows the respective gap to be implemented in a very simple manner from a design and manufacturing perspective. Furthermore, the area of ​​the gap can be easily maximized without significantly impairing the stability of the one-piece fan wheel according to the invention. The preferred embodiment of this development specifies a design of the respective gap that is particularly relevant for practical purposes. The root of the gap, formed as the apex of a triangle, can also be rounded.

[0016] Furthermore, a further advantageous embodiment of the fan wheel according to the invention provides that the fan wheel has a circumscribed diameter of 140 mm to 144 mm. In this way, a key dimension of the fan wheel according to the invention is particularly well suited to practical operating conditions.

[0017] An embodiment of the invention is shown purely schematically in the drawings and is described in more detail below. It shows Figure 1 shows an embodiment of the cooking appliance according to the invention with the fan wheel according to the invention in a partial frontal view, without the fan wheel; Figure 2 shows the embodiment in an analogous representation to the Fig. 1 , with fan wheel, Figure 3 the embodiment according to the Fig. 2 Figure 4 shows the fan wheel of the exemplary embodiment in a sectional side view, Figure 5 shows the fan wheel of the exemplary embodiment in a perspective view, and Figure 6 shows the fan wheel in a view relative to the Fig. 5 corresponding partial, enlarged view.

[0018] In the Fig. 1 bis 6 An embodiment of the cooking device according to the invention, including the fan wheel according to the invention, is shown purely as an example.

[0019] The cooking appliance 2, with a cooking chamber (not shown), is designed here as a household steam cooker and comprises a wall 4 with a fresh air opening 6 for introducing fresh air (not shown) into the cooking chamber and a fan (not shown) with a fan wheel 8 arranged on the cooking chamber side of the wall 4 for drawing fresh air through the fresh air opening 6 into the cooking chamber. The fan wheel 8 has a base plate 10 arranged in front of the fresh air opening 6 and air conveying elements 22 arranged on the side of the base plate 10 facing away from the fresh air opening 6 and is rotatable about an imaginary axis of rotation perpendicular to the base plate 10. A fresh air damper, which closes or opens the fresh air opening 6 as desired, is located in the Fig. 1 bis 6 not shown and designed according to the state of the art. See also the relevant explanations in the introductory description.

[0020] According to the invention, the fan is designed as a reversible fan, and the respective dimensions and spatial configuration of the fresh air opening 6 and the fan wheel 8, as well as the spatial arrangement of the fresh air opening 6 relative to the fan wheel 8, are coordinated such that a sufficiently high negative pressure can be generated between the fresh air opening 6 and the base plate 10 of the fan wheel 8 in both directions of rotation. This ensures that, regardless of the direction of rotation, the required quantity of fresh air is introduced into the cooking chamber through the fresh air opening 6 in every relevant operating state of the cooking appliance 2. For example, the combination of steam cooking and baking is steadily gaining popularity. The targeted, direction-independent supply of fresh air allows fresh air to enter the cooking chamber and, for example, influence the browning rate.The fan wheel 8, which rotates in both directions, must be slowed down and accelerated again each time the direction of rotation changes. Changing the direction of rotation improves heat distribution in the cooking chamber. Therefore, it is very advantageous if the fan wheel 8 is lighter. See the following explanations for further details.

[0021] The fresh air opening 6 is designed here as a circular opening with a clear cross-section a of 27 mm. Furthermore, the horizontal distance b between the imaginary axis of rotation of the fan wheel 8 and a center point of the fresh air opening 6, which is designed as a circular opening, is 48 mm, wherein the aforementioned center point of the fresh air opening 6 is vertically offset by c = 10 mm relative to the imaginary axis of rotation of the fan wheel 8, and wherein a rear side of the base plate 10 facing the fresh air opening 6 has a distance d to the fresh air opening 6 of 16 mm. See in particular the Fig. 1 and 3 The cutting path in the Fig. 3 is in the Fig. 2 characterized by the section line AA.

[0022] Furthermore, the fresh air opening 6 and a shaft opening 12 for a shaft of the fan (not shown) for driving the fan wheel 8 are arranged in a surface 16 of the wall 4 that is recessed from a base surface 14 of the wall 4 facing the cooking chamber, wherein the recessed surface 16 is bounded by two semicircular contours, and wherein one semicircular contour is assigned to the fresh air opening 6 and the shaft opening 12, and the semicircular contours are connected on both sides by a straight contour, namely such that the semicircular contours have a radius e of 34 mm and the straight contours have a length f of 18 mm.Furthermore, the centers of circles corresponding to the semicircular contours have a horizontal distance g of 18 mm and a vertical distance h of 4 mm from each other, with the two centers of circles, the center of the fresh air opening, and the imaginary axis of rotation lying essentially on a common imaginary line. The recessed surface 16 is connected to the base surface 14 by a circumferential connecting surface 18 of the wall 4, and the connecting surface 18 forms an obtuse angle, namely an angle Φ of 135°, with the recessed surface 16. See in particular the [reference missing]. Fig. 3 . One axis of the shaft (not shown) corresponds to the imaginary axis of rotation of the fan wheel 8.

[0023] In the present embodiment, wall 4 with fresh air opening 6 and shaft opening 12 and fan wheel 8 are separated from the cooking chamber by an intermediate wall (not shown), the intermediate wall having openings for the fresh air conveyed by the fan wheel 8. Such an intermediate wall is also referred to as an adjustment wall and gives the cooking chamber a better overall visual appearance.

[0024] The fan wheel 8 comprises the aforementioned base plate 10 with a central section 20 for attaching the fan wheel 8 to the fan shaft, which extends perpendicular to the base plate 10 for driving the fan wheel 8, and a plurality of air conveying elements 22 arranged on the base plate 10 for conveying the air. The air conveying elements 22 are arranged evenly distributed around the circumference of the central section 20 and each extends radially outwards. The air conveying elements 22 are each aligned with a surface center 23 of the central section 20, such that the air conveying elements 22 extend along straight lines radiating from the surface center 23. The fan wheel 8 has an opening at the surface center 23 for receiving the shaft that drives the fan wheel 8. Furthermore, in the present embodiment, the fan wheel 8 has a circumscribed diameter of 142 mm.

[0025] According to the invention, the air conveying elements 22 are each arranged on a wing 24 of the base plate 10, the wings 24 being evenly distributed around the circumference of the central section 20 and extending radially outwards from the central section 20 such that, between directly adjacent wings 24, the base plate 10 has a gap 26 extending from the free ends of these wings 24 to a gap root. The respective gap 26 extends from the corresponding free ends in a triangular shape to the gap root of this gap 26, which is formed as the apex of the triangle. This gap 26 has an opening angle A of 60° and a gap depth B of 30 mm, measured from an imaginary circular path 28 of the free ends to the gap root. In the present embodiment, the base plate 10 with the wings 24 is planar. See in particular the Fig. 4 bis 6 .

[0026] Furthermore, the fan wheel 8 is designed here as a one-piece sheet metal part, which simultaneously serves as a bent part for realizing the blades 24 with the air conveying elements 22. The fan wheel 8 is also designed as an embossed part for stiffening the central section 20 and the blades 24, wherein the central section 20 and the blades 24 have a single, common embossing 30, namely such that this embossing 30 has a circular annular contour spatially separating the central section 20 from the blades 24, with radial rib contours extending into the individual blades 24.

[0027] Due to the inventive design of the cooking appliance 2 with the cooking chamber and the fan wheel 8 for this cooking appliance 2, it is reliably ensured that a sufficiently high negative pressure can be generated between the fresh air inlet 6 and the base plate 10 of the fan wheel 8 in both directions of rotation. This ensures that, regardless of the direction of rotation, the required quantity of fresh air is introduced into the cooking chamber through the fresh air inlet 6 in every relevant operating state of the cooking appliance 2. As is customary, the fresh air inlet 6 has a fresh air flap and serves in particular to regulate humidity in the cooking chamber. Depending on the humidity level and operating mode, i.e., operating state, the fresh air flap is opened or closed, so that fresh air is supplied to the cooking chamber or not. The invention according to the present embodiment serves to generate sufficient negative pressure behind the fan wheel 8.The particular challenge lies in achieving a sufficiently high negative pressure in both directions of rotation. In addition to the optimal design of the fresh air inlet 6 with the fresh air flap, it is also necessary to ensure the best possible air circulation through the cooking chamber using the fan wheel 8. This is also made possible by the invention according to the present embodiment. Furthermore, due to the inventive design of the fan wheel 8, a significant weight reduction is achieved compared to the prior art, while maintaining at least the same flow velocity of the fluid conveyed, thus substantially reducing the energy required to rotate this fan wheel 8.This is particularly advantageous for the present fan wheel 8, which is designed as a reversible fan wheel, i.e., a fan wheel that can rotate in one direction or the other depending on the operating condition. The reduced rotating mass proves advantageous both when accelerating and decelerating the fan wheel 8. Compared to the prior art, the fan wheel 8 achieves a weight reduction of approximately 25%. Accordingly, with the present embodiment, it is possible to operate the fan wheel 8 at a lower speed with the same power output, i.e., with comparable airflow velocities, in both the cooking appliance 2 and the fan wheel 8. The response of the fan wheel 8 is also significantly improved when changing its direction of rotation due to the weight reduction.On the other hand, the fan wheel 8 can be manufactured in a very simple way in terms of design and production technology and also requires significantly less installation space than state-of-the-art fan wheels that have a comparable performance.

[0028] However, the invention is not limited to the present embodiment. See, for example, the relevant explanations in the introductory section of the description and the alternative or optional features listed in the specific description section. The fan wheel need not necessarily be a single piece or be formed from a sheet metal part.

Claims

1. Cooking appliance (2) with a cooking chamber, comprising a wall (4) with a fresh air opening (6) for introducing fresh air into the cooking chamber and a fan with a fan wheel (8) arranged on the cooking chamber side of the wall (4) for drawing fresh air through the fresh air opening (6) into the cooking chamber, wherein the fan wheel (8) has a base plate (10) arranged in front of the fresh air opening (6) and air conveying elements (22) arranged on the side of the base plate (10) facing away from the fresh air opening (6) and wherein the fan wheel (8) is rotatable about an imaginary axis of rotation extending perpendicular to the base plate (10), characterized by the fact that the wall (4) has a shaft opening (12) for a shaft of the fan for driving the fan wheel (8), wherein the wall (4) with the fresh air opening (6) and the shaft opening (12) and the fan wheel (8) are separated from the cooking chamber by an intermediate wall, wherein the intermediate wall has passage openings for the fresh air conveyed by the fan wheel (8).

2. Cooking appliance (2) according to claim 1, wherein the fresh air opening (6) is designed as a circular opening with a clear cross-section (a) of 27 mm and / or, that a horizontal distance (b) between the imaginary axis of rotation of the fan wheel (8) and a center point of the fresh air opening (6) designed as a circular opening is 48 mm.

3. Cooking appliance (2) according to one of the two preceding claims, wherein the aforementioned center point of the fresh air opening (6) is arranged vertically offset by (c) 10 mm relative to the imaginary axis of rotation of the fan wheel (8), and / or wherein a rear side of the base plate (10) facing the fresh air opening (6) has a distance (d) to the fresh air opening (6) of 16 mm.

4. Cooking appliance (2) according to one of the preceding claims, wherein the fresh air opening (6) and a shaft opening (12) for a shaft of the fan for driving the fan wheel (8) are arranged in a surface (16) of the wall (4) that is set back from a base surface (14) of the wall (4) facing the cooking chamber.

5. Cooking appliance (2) according to the preceding claim, wherein the recessed surface (16) is bounded by two semicircular contours, one semicircular contour being assigned to the fresh air opening (6) and the wave opening (12), and the semicircular contours being connected on both sides by a straight contour.

6. Cooking appliance (2) according to the preceding claim, wherein the semicircular contours have a radius (e) of 34 mm and the straight contours have a length (f) of 18 mm and / or wherein the centers of circles corresponding to the semicircular contours have a horizontal distance (g) of 18 mm and a vertical distance (h) of 4 mm from each other, wherein the two centers of circles, the center of the fresh air opening (6) and the imaginary axis of rotation lie substantially on a common imaginary straight line.

7. Cooking appliance (2) according to the preceding claim, wherein the recessed surface (16) is connected to the base surface (14) by a circumferential connecting surface (18) of the wall (4) and the connecting surface (18) forms an obtuse angle, preferably an angle (Φ) of 135°, with the recessed surface (16).

8. Cooking appliance (2) according to one of the preceding claims, wherein the fan wheel (8) has a base plate (10) with a central section (20) for attaching the fan wheel (8) to a shaft of the fan extending perpendicular to the base plate (10) for driving the fan wheel (8) and a plurality of air conveying elements (22) arranged on the base plate (10) for conveying the air, and wherein the air conveying elements (22) are arranged uniformly distributed over the circumference of the central section (20) and each extend radially outwards, characterized by the fact thatThe air conveying elements (22) are each arranged on a wing (24) of the base plate (10), wherein the wings (24) are arranged evenly distributed over the circumference of the central section (20) and extend radially outwards from the central section (20) in such a way that between directly adjacent wings (24) starting from free ends of these wings (24) the base plate (10) has a gap (26) extending into a gap root.

9. Cooking appliance (2) according to the preceding claim, wherein the fan wheel (8) is designed as a one-piece sheet metal part, wherein the sheet metal part is simultaneously designed as a bent part for realizing the vanes (24) with the air conveying elements (22).

10. Cooking appliance (2) according to one of the two preceding claims, wherein the fan wheel (8) is designed as a one-piece sheet metal part, wherein the sheet metal part is simultaneously designed as an embossed part for stiffening the central section (20) and / or the wings (24).

11. Cooking appliance (2) according to the preceding claim, wherein the central section (20) and the wings (24) have a single, common embossing (30).

12. Cooking appliance (2) according to the preceding claim, wherein this embossing (30) has a circular ring contour spatially separating the central section (20) from the wings (24) with radial rib contours extending into the individual wings (24).

13. Cooking device (2) according to one of the five preceding claims, wherein the respective gap (26) extends from the corresponding free ends in a triangular shape to the root of this gap (26) which is formed as a triangular apex, preferably that this gap (26) has an opening angle (A) of 60° and / or has a gap depth (B) of 30 mm measured from an imaginary circular path (28) of the free ends to the root of the gap.

14. Cooking appliance (2) according to one of the six preceding claims, wherein the fan wheel (8) has a circumscribed diameter of 140 mm to 144 mm.

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