EP2741013B1 - Cooking appliance with a fan and an adjusting device - Google Patents

Description

The present invention relates to a cooking appliance, in particular an oven.

It is known to operate ovens in different operating modes. For example, a first mode of operation may be a hot air mode of the cooking appliance in which a food is baked in the oven oven. A second operating mode may be, for example, a pyrolysis operation of the oven, in which the oven is burned out. This dirt is carbonized so that it either falls off by itself or can be easily removed. While temperatures of, for example, up to 230 ° in the oven occur in hot air operation, there are up to 600 ° in pyrolysis.

Due to the different operating temperatures, there are different requirements for such ovens, in particular to cool electronic components and a periphery of the same. From the prior art, it is therefore known to provide a cooling fan for cooling the oven in the pyrolysis with higher power, so that a larger cooling air volume flow is achieved in order to provide the necessary cooling. In hot air operation, the cooling fan is supplied with a lower power and therefore generates a lower cooling air volume flow to provide the necessary cooling.

EP 1 566 594 A1 describes a method and a device for loading and / or venting a cooking oven comprising at least one oven muffle and a door for closing a feed opening of the oven muffle in a closed state and at least one cooking operation for cooking food in the oven muffle and a pyrolytic pyrolysis Cleaning the oven muff has.

Especially in pyrolysis operation, a high cooling air volume flow is required. On the one hand, this has a negative impact on energy efficiency but also on the noise pollution from the oven. In addition, the required cooling fan is large and therefore expensive.

Object of the present invention is therefore to provide an improved cooking appliance.

Accordingly, a cooking appliance, in particular an oven, with at least one fan, a first and a second zone and at least one adjusting device is provided. The adjusting device is set up in a first operating mode of the cooking appliance of the first zone a first air volume flow and the second zone a second air volume flow and in a second operating mode of the cooking appliance of the first zone to supply a third air volume flow and the second zone a fourth air volume flow. With constant fan power in the first and second operating modes, the first and third air volume flow and the second and fourth air volume flow differ from each other. Alternatively, at different fan outputs of the fan in the first and second modes of operation, the first and third airflows are different from each other, and the second and fourth airflows are the same.

The idea on which the present invention is based is to selectively supply the first and second zones, depending on the operating mode and the associated cooling task, with the appropriate air volume flow in order to ensure sufficient cooling there. While in the prior art, the distribution of cooling air is fixed and not changeable, that is no way to selectively cool the individual zones, in the present case, the admission of individual zones with cooling air is variable depending on the operating mode and in particular such that thermal limits in the area the first and second zones are not exceeded.

As a result, advantageously no zones are cooled more than necessary, whereby the energy efficiency of the cooking appliance can be improved. In addition, the maximum air volume flow and / or the averaged over the operating time air volume flow of the cooking appliance can be reduced, whereby an emanating from the cooking appliance noise pollution can be minimized. Furthermore, a smaller fan can be used, whereby costs can be saved.

The first to fourth air volume flow may each be a cooling air volume flow. However, it is also possible that the first and third air volume flow in each case a cooling air volume flow and the second and fourth air volume flow are each a Wrasenluftstrom from the cooking chamber of the cooking appliance.

In the present case, "oven" should also include combination appliances, such as a microwave oven.

• wobei V dem Luftvolumenstrom,
• Δp der Totaldruckerhöhung über dem Lüfter, und
• n dem Wirkungsgrad des Lüfters entspricht.

The "fan power" P is defined as: $$\mathrm{P}=\mathrm{V}\times \mathrm{Ap}/\mathrm{n}.$$

• where V is the air volume flow,
• Δp the total pressure increase over the fan, and
• n corresponds to the efficiency of the fan.

Basically, a wide variety of operating modes are conceivable. For example, the operating modes may differ with respect to the respective temperature or with respect to a respective temperature range in the cooking chamber of the cooking appliance.

The first and second zones are selected from the group: a front of the cooking appliance, at least one furniture-side surface of the cooking appliance and / or a cooking chamber of the cooking appliance.

By "front" is meant an operator-facing side of the cooking appliance during operation thereof. This must, for example, be strongly cooled in a hot air operation of the cooking appliance in order to prevent burns of persons who accidentally come into contact with the front of the cooking appliance, in particular children. In contrast, in a pyrolysis operation, which takes place only rarely and deliberately, so that appropriate safety precautions can be taken, for example, children are not allowed access to the kitchen in which the cooking appliance is located, the front can be very hot and must accordingly be cooled only slightly , Due to the high temperatures in the cooking chamber in the pyrolysis operation, however, the electronic components must be cooled much more than is the case in the hot air operation. In the present case, "electronic" components also include electromechanical components.

It could also be provided more than two zones, for example, three zones, which are selectively cooled. For the third zone then the already executed to the first and second zone applies. The third zone could also be selected from the aforementioned group.

According to a further embodiment, the front comprises a door.

The air flow for cooling the door is sucked through the door. For this purpose, the door can be equipped, for example, with a double duct system.
Further, for example, a space of the cooking appliance for receiving at least one electronic component, an electric motor, a circuit board and / or an electric actuator take up. These components may for example have a thermal limit temperature of 85 °, which may not be exceeded regardless of the operating mode of the cooking appliance. In the present case, "electrical" also includes "electromechanical".

Furthermore, the space may be formed, for example, as a switch room.

The switch room of a cooking appliance usually comprises a central control unit, in particular in the form of a board, of the cooking appliance.

According to a further embodiment, the furniture side surface is formed as a side surface.

In the installation position of the cooking appliance, the furniture-side surface, in particular the side surface, adjoins surrounding material, in particular wood. Since the thermal limit temperature of wood is typically 95 ° (at 25 ° room temperature), the temperature of the furniture side surface, in particular the side surface, must not exceed this limit temperature. At the same time, however, the temperature of the furniture-side surface, in particular the side surface, should not be significantly below this limit temperature, since the cooling is otherwise inefficient. For example, the temperature of the furniture side surface, in particular the side surface should be in a range of, for example, 85 to 90 ° (at 25 ° room temperature). The adjusting device can be set up accordingly.

According to a further embodiment, the first operating mode is a hot-air operation and / or the second operating mode is a pyrolysis operation.

Especially with these two operating modes, the cooling requirements are very different, so that there are great efficiency improvements according to the solution described above

According to a further embodiment, the first zone is part of a first air duct connected to the cooling fan and the second zone is part of a second with the cooling fan connected air duct. Preferably, the at least one adjusting device is adapted to change a flow resistance and / or flow cross-section of the first and / or second air duct depending on the selected operating mode.

If, for example, the flow resistance in the first air duct is increased by means of the adjusting device, the fan sucks correspondingly more air from the second air duct, so that the cooling in the first zone deteriorates and improves in the second zone.

According to a further embodiment, the first and second zones are each assigned a temperature limit value in the first and second operating modes. The at least one adjusting device is preferably set up to adjust the flow resistance such that the temperature in the first and second zones does not exceed the temperature limit value.

According to a further embodiment, the at least one adjusting device has an adjustable slide, an adjustable flap and / or an adjustable venturi jump.

The aforementioned means are each adapted to increase or decrease the flow resistance.

According to a further embodiment, the adjusting device is adapted to interconnect the first and second air guide with each other in an air-conducting manner.

As a result, the air volume flows can be influenced and thus a targeted cooling of the first or second zone can be achieved.

According to a further embodiment, the adjusting device has a flow resistance which increases asymptotically as the negative pressure applied to the adjusting device increases.

In other words, the air volume flow rate through the actuator does not increase from a certain operating vacuum, although the operating vacuum, for example by increasing the fan power continues to increase. The adjusting device is thus self-limiting and advantageously requires no moving actuators. Examples of such a setting device are a suitably designed grid or other geometry. The self-locking effect may be based on the generation of suitable turbulences.

According to a further embodiment, the adjusting device can be controlled by means of a vapor control for changing the flow resistance.

By the simultaneous use of Wrasensteuerung to drive the actuator components can be saved.

According to a further embodiment, the cooking appliance is designed as a built-in appliance.

Especially with built-in appliances in kitchens compliance with limit temperatures at the front or on a furniture-side surface of the cooking appliance is of particular importance.

Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the embodiments of the invention described below. Furthermore, the invention will be explained in more detail by means of preferred embodiments with reference to the attached figures.

Fig. 1

prinzipiell ein Lüftungssystem bei einem Gargerät gemäß einer Ausführungsform;

Fig. 2

schematisch einen horizontalen Schnitt durch ein Gargerät gemäß einer weiteren Ausführungsform;

Fig. 3

einen vertikalen Schnitt durch ein Gargerät gemäß einer weiteren Ausführungsform;

Fig. 4A

einen vertikalen Schnitt durch ein Gargerät gemäß einer weiteren Ausführungsform;

Fig. 4B

den Luftwiderstand einer Stelleinrichtung aus Fig. 4A in Abhängigkeit von einem an dieser anliegenden Unterdruck; und

Fig. 5

teilweise einen Vertikalschnitt durch ein Gargerät gemäß einer weiteren Ausführungsform.

It shows:

Fig. 1

in principle, a ventilation system in a cooking appliance according to one embodiment;

Fig. 2

schematically a horizontal section through a cooking appliance according to another embodiment;

Fig. 3

a vertical section through a cooking appliance according to another embodiment;

Fig. 4A

a vertical section through a cooking appliance according to another embodiment;

Fig. 4B

the air resistance of a control device Fig. 4A depending on a voltage applied to this negative pressure; and

Fig. 5

partly a vertical section through a cooking appliance according to another embodiment.

In the figures, the same or functionally identical elements have been given the same reference numerals, unless stated otherwise.

Fig. 1 shows a schematic diagram of a ventilation system in a cooking appliance 1 according to one embodiment.

The cooking appliance 1 is formed according to the embodiment as an oven, in particular as a built-in appliance in a kitchen.

The oven 1 comprises a fan 2 for generating an air volume flow 3. On the pressure side, the air volume flow 3 leads into the environment 4. The suction side of the fan 2 with four air ducts 5, 6, 7, 8, for example, is air-conductively connected. The air ducts 5, 6, 7, 8 are each formed by particular walls of the cooking appliance 1, for example u. a. in the form of pipes or even rectangular air duct cross-sections.

Component of a respective air guide 5, 6, 7, 8 is a first, second, third or fourth zone 11, 12, 13 and 14 (only for better illustration, the zones 11, 12, 13, 14 are left of the air ducts 5, 6, 7, 8). For example, the zone 11 may take the form of an in FIG. 2 be formed door shown. The second zone 12 may take the form of in FIG. 2 shown side surfaces which adjoin a furniture 15, in which the oven 1 is installed, be formed. The second zone 12 may also have an in FIG. 3 shown top 16 and a rear wall 17 of the oven 1 include. The third zone 13 is for example as in FIG. 3 shown oven of the oven 1 is formed. The fourth zone 14 is designed, for example, as a switch room, which accommodates a control electronics of the cooking appliance 1 formed on a printed circuit board.

In a hot air operation of the cooking appliance 1, for example, there is a temperature in the cooking chamber 13 of 180 °. In the present case, the door 11 may not exceed a temperature limit of, for example, 65 °, since otherwise these persons, in particular children, could burn themselves. Therefore, a relatively strong cooling must be provided. According to the exemplary embodiment, this is done by providing a device 21 in the form of a switchable air duct 23, which connects the air duct 5 with the air duct 6 in the hot air mode. This results in a large flow of cooling air 22 through the door 11, which on the one hand via the air guide 5 itself sucked (see reference numeral 22 ') and on the other hand via the air guide 23 and the air duct 6 (see reference numeral 24) is sucked. Accordingly, then the air flow 25 for cooling the side surfaces 12, the top 16, the back 17 and the furniture 15 is small. The temperature of the furniture 15 can then be up to 90 °.

If switching is now made to the rather rarely used pyrolysis operation, the air guide 23 is switched in such a way that the air volume flow 24 toward the air guide 6 is stopped. By way of example, the pyrolysis operation is a second operating mode of the cooking appliance 1. Without the air volume flow 24, the air volume flow 25 becomes larger (this larger air volume flow is designated by 25 '). Accordingly, the side surfaces 12, the top and back 16, 17 and the furniture 15 are more cooled, but this is also necessary because prevail in pyrolysis, for example, about 485 ° in the cooking chamber 13 and accordingly much more heat is released to the outside , The temperature of the furniture can be kept at 90 °. At the same time the temperature of the door 11 is significantly higher, for example at 95 °, because - due to the lack of air volume flow 24-the air volume flow 22 is smaller (this smaller air volume flow is denoted by 22 ').

Thus, specifically a different cooling in the different zones 11, 12 is provided without the fan power of the fan 2 would have to be changed. However, in addition, the fan power could also be changed.

At the same time, the air volume flow 26 through the third zone 13 or an air flow 27 through the fourth zone 14 could be changed.

FIG. 2 illustrates a horizontal section through a cooking appliance 1 according to another embodiment.

This in FIG. 1 The principle described here is used here in a somewhat modified form: While the device 21 in FIG Fig. 1 is arranged to connect the air ducts 5, 6, which are assigned to different zones 11, 12, to each other, the oven 1 after FIG. 2 two devices 21 in the form of an adjustable slide 31 and an adjustable flap 32 on. Openings 33 and 34 are closed by means of the slide 31 or the flap 32 or (at least partially) opened to adjust the air volume flow 25 or 25 '. If the small air volume flow 25 is set, the result is automatically a larger air volume flow 22 through the door 11, which can be embodied with a double air duct system through which the air volume flow 22 flows. The openings 33, 34 may be provided in the side surfaces 12. An air gap between the oven 1 and the surrounding furniture, such as wood, is designated 35. For this, the air flow 25 is sucked.

FIG. 3 shows a vertical section through a cooking appliance 1 according to another embodiment.

In the embodiment according to FIG. 3 is not the opening 33 in the side wall 12, as at FIG. 2 but arranged in the rear wall 17. Further, a slider 31 for opening and closing the opening 33 is provided. The slide 31 is coupled via a coupling rod 36 with an adjustable Venturi jump 37. The Venturi jump 37 is overflowed by the pressure-side air volume flow 3 of the fan 2, so that, depending on how far the Venturi jump 37 is opened, a different suction pressure is applied to the air guide 7. Accordingly, a more or less large air flow 26 through the cooking chamber 13 is formed. If the air volume flow 26 is large, the air volume flow 25 through the opening 33 becomes correspondingly smaller, and vice versa. Advantageously, by means of the coupling rod 36, a movement of the Venturi jump 37 can be coupled with a movement of the slide 31. Thus, it can be provided that the slide 31 closes increasingly, the farther the Venturi jump 37 is opened, and vice versa.

FIG. 4A shows a vertical section through a cooking appliance 1 according to another embodiment.

In the embodiment according to FIG. 4A is in the opening 33, a grid 41 is arranged. By this the air volume flow 25 reaches the fan 2. Accordingly, no slide 31 and no coupling rod 36, as still in FIG. 3 shown, provided. The Venturi-Schanze 37 out Fig. 3 can be optionally provided. The grid 41 has the basis of the diagram FIG. 4B shown properties. The air resistance of the grid 41 increases asymptotically with increasing negative pressure. An asymptote is designated 42. That is, the grille 41 is self-regulating, with the air resistance increasing so much that the grille 41 passes practically no air or only a small amount of air when the negative pressure approaches the asymptote 42. By negative pressure is meant here the pressure on the side of the grille 41, which is located upstream with respect to the fan 2.

In the embodiment according to Fig. 4A For example, in the hot air or pyrolysis operation, the fan power 2 can be increased via the negative pressure associated with the asymptote 42, without the air volume flow 25 changing (ie remaining the same). At the same time, however, the air volume flow 22 through the door 11 (not shown) increase, since now at the air guide 5, a greater negative pressure is applied.

FIG. 5 shows a vertical section through a baking oven 1 according to another embodiment.

In the embodiment according to FIG. 5 an adjustable venturi 37 is provided, which closes or opens the air duct 5 as needed. If the venturi jump 37 is opened further, for example, the air volume flow 25 decreases correspondingly via the second zone 12 (not shown). If the venturi 37 further closed, the air flow increases accordingly.

The different air volume flows 22, 22 ', 25, 25', 26, 27 could also be achieved by using a plurality of fans 2, which are individually adjustable.

Although the invention has been described in the present case with reference to exemplary embodiments, it is not limited thereto but can be modified in many ways.

Used reference signs:

1

oven

2

Fan

3

Airflow

4

Surroundings

5

air duct

6

air duct

7

air duct

8th

air duct

11

first zone

12

second zone

13

third zone

14

fourth zone

15

Furniture

16

top

17

rear wall

21

setting device

22

Airflow

22 '

Airflow

23

air duct

24

Airflow

25

Airflow

25 '

Airflow

26

Airflow

27

Airflow

31

pusher

32

flap

33

opening

34

opening

35

gap

36

coupling rod

37

Venturi hill

41

grid

42

asymptote

Claims (12)

1. Cooking appliance (1), especially an oven, with a fan (2), at least one first and one second zone (11, 12, 13, 14), and at least one adjusting device (21) which is configured so as to feed a first volumetric air flow (22) to the first zone (11) and a second volumetric air flow (25) to the second zone (12) in a first operating mode of the cooking appliance (1), and also a third volumetric air flow (22') to the first zone (11) and a fourth volumetric air flow (25') to the second zone (12) in a second operating mode of the cooking appliance (1), wherein the volumetric air flows (22, 22', 25, 25') can be fed in a variable manner to the first and second zones (11, 12, 13, 14) for the purpose of cooling according to the operating mode, wherein the first and third volumetric air flows (22, 22') and the second and fourth volumetric air flows (25, 25') differ from each other when the fan (2) has a constant output in the first and second operating modes, or the first and third volumetric air flows (22, 22') differ from each other and the second and fourth volumetric air flows (25, 25') are the same when the output of the fan (2) differs in the first and second operating modes, wherein the first and second zones (11, 12, 13, 14) are different elements which are selected from the group: a front of the cooking appliance (1), at least one furniture-side surface of the cooking appliance (1), and/or a cooking compartment of the cooking appliance (1).
2. Cooking appliance according to claim 1, characterised in that the front comprises a door (11).
3. Cooking appliance according to one of claims 1 - 2, characterised in that the furniture-side surface (12) is realised in the form of a side surface of the cooking appliance (1).
4. Cooking appliance according to one of claims 1 - 3, characterised in that a cooking compartment (13) of the cooking appliance (1) has a higher temperature in the second operating mode than in the first operating mode.
5. Cooking appliance according to claim 4, characterised in that the first operating mode is a hot air mode and/or the second operating mode is a pyrolytic mode.
6. Cooking appliance according to one of claims 1 - 5, characterised in that the first zone (11) is part of a first air duct (5) connected to the fan (2) and the second zone (12) is part of a second air duct (6) connected to the fan (2) and that the at least one adjusting device (21) is configured so as to change a flow resistance and/or a flow cross-section of the first and/or second air duct(s) (5, 6) as a function of the operating mode selected.
7. Cooking appliance according to claim 6, characterised in that a temperature threshold value is assigned to each of the first and second zones (11, 12) in the first and second operating modes and that the at least one adjusting device (12) is configured so as to adjust the flow resistance and/or flow cross-section such that the temperature in the first and second zones (11, 12) does not exceed the respective temperature threshold value.
8. Cooking appliance according to one of claims 1 - 7, characterised in that the at least one adjusting device (21) has an adjustable gate valve (31), an adjustable flap (32) or an adjustable Venturi channel (37).
9. Cooking appliance according to one of claims 1 - 7, characterised in that the adjusting device (21, 23) is configured so as to connect the first and second air ducts (5, 6) together so as to conduct air.
10. Cooking appliance according to one of claims 1 - 7, characterised in that the adjusting device (21, 41) has a flow resistance which increases in an asymptotic manner with increasing underpressure applied to the adjusting device (21, 41).
11. Cooking appliance according to one of claims 6 - 9, characterised in that the adjusting device (21, 37) can be activated so as to change the flow resistance by using a vapour control system.
12. Cooking appliance according to one of claims 1 - 11, characterised in that the cooking appliance (1) is realised as a built-in appliance.

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