Extractor hood to be operated in exhaust and recirculation mode

Abstract

Extractor hood (1) to be operated in exhaust air and / or recirculation mode, comprising a control device (9) and an air guidance system, which includes a switching device (4) for carrying out exhaust air and recirculation modes, characterized by that the extractor hood (1) has control and air guidance means which are configured and designed such that the extractor hood (1) can be operated in recirculation mode with a reduced air flow rate compared to exhaust air mode, wherein the reduction of the air flow rate in recirculation mode is achieved by a control and air guidance means in the extractor hood (1) The noise sensor is arranged and connected to the control unit (9).

Description

[0001] The invention relates to a range hood that can be operated in exhaust air and / or recirculation mode, comprising a control unit and an air distribution system, which includes a switching device for carrying out exhaust air and recirculation operation. Furthermore, the invention relates to a method for operating a range hood designed according to the invention.

[0002] As is well known, cooker hoods can be equipped to operate in both recirculation and extraction modes. In practice, switching devices are used in the airflow path to allow the cooker hood to be operated in either extraction or recirculation mode. The advantage of extraction mode is that a high air volume and thus high operating efficiency can be achieved. In contrast, in recirculation mode, warm room air is not extracted to the outside, but rather cleaned and returned to the kitchen. In this mode, the odor-laden air can also be advantageously passed through an activated carbon filter, so that the odors inevitably produced during cooking can be eliminated.

[0003] German patent DE 78 02 041 U1 discloses a cooker hood with at least one fan and at least one filter for installation above kitchen stoves. This cooker hood can be switched between recirculation and exhaust air operation by means of a guide element that can be inserted into the ductwork.

[0004] It is known from the publication EP 2 570 735 A1 that a switchable air guide device is provided in an air duct in a cooker hood, which can be set to several operating positions in order to direct the air through different channels.

[0005] From EP 1 055 883 B1, for example, it is known to provide a switching device that can be controlled depending on the outside temperature, by means of which the switch from exhaust air operation to recirculation operation is carried out automatically. Furthermore, an embodiment is provided in which the switching device allows a mixed operation with an exhaust air and a recirculation component in an intermediate position. The temperature-controlled switching device is intended to switch more and more to recirculation operation during the cold season in order to ensure the most energy-efficient operation possible.

[0006] In the embodiments known from the prior art to date, it is considered a disadvantage that the recirculation operation can lead to a higher noise level due to the system's inherent characteristics.

[0007] The invention therefore addresses the problem of providing a range hood of the type mentioned above in which any disturbing operating noises are avoided after switching to recirculation mode.

[0008] According to the invention, this problem is solved by a cooker hood with the features of claim 1. Advantageous embodiments and further developments of the invention are described in the dependent claims. Furthermore, claim 9 and the claims relating thereto specify an advantageous method for operating a cooker hood designed according to the invention.

[0009] The advantages achievable with the invention lie particularly in the fact that a cooker hood is offered with a new additional function, allowing the user or an automatic control configuration to react to any noise that may occur during recirculation mode. By manually adjusting or sensor-controlled reducing the airflow, the noise associated with recirculation mode can be minimized or completely avoided.

[0010] The extractor hood can be advantageously configured to operate in pure exhaust air mode, pure recirculation mode, or a combined mode. The recirculation mode can be deliberately activated on an individual basis.

[0011] The control concept according to the invention can be advantageously and expediently used, in particular, in cooker hoods that are normally designed as exhaust hoods. The user can then freely decide whether and when to use recirculation mode to eliminate unpleasant odors. For this purpose, the cooker hood is equipped with control and switching means as well as air guides so that the cooker hood can be operated in recirculation mode with a reduced airflow compared to exhaust mode. The airflow can be influenced by a speed-controlled fan or by a switching device with an adjustable air damper in conjunction with the electronic control unit of the appliance.

[0012] In a first embodiment, a manually operated switch is provided for activating the recirculation mode in conjunction with the control unit of the extractor hood. In this version, the user has complete freedom to choose whether or not to use the recirculation mode. If unpleasant odors occur in the kitchen, the user can switch to recirculation mode to eliminate them, or activate exhaust mode without having to tolerate any disturbing noises.

[0013] The reduction in recirculation rate can be derived from empirically determined values ​​for the specific recirculation system used. Based on this, the electronic control unit can then be configured so that the fan speed or the air damper in the switching device is controlled in such a way that recirculation occurs at an airflow rate that prevents disturbing noise. Thus, an airflow rate can be set at which the operating noise during recirculation is barely audible or considered tolerable by the user.

[0014] In an advantageous embodiment of the invention, the control unit of the device and the switching device can be configured and designed in such a way that, in mixed operation, the recirculation rate can be adjusted so that no disturbing noises can occur automatically due to the reduced airflow in the recirculation circuit.

[0015] According to the invention, an automatic, sensor-controlled switch to recirculation mode is provided, in which a noise sensor causes the activation or the switch to recirculation mode.

[0016] Additionally, an odor sensor located near the hood's canopy can detect odors and then trigger the control unit to switch to recirculation mode. Furthermore, a noise sensor can be placed at a point in the extractor hood's ductwork where, based on experience, increased noise levels are expected due to existing flow resistance. Upon reaching a predetermined noise threshold, the noise sensor can then switch the system to recirculation mode with reduced airflow.

[0017] An embodiment of the invention is shown purely schematically in the single drawing and is described in more detail below. The drawing shows in a schematic diagram the air duct paths of a cooker hood designed for exhaust and recirculation operation with the components essential for explaining the invention.

[0018] In the drawing, a range hood 1 is symbolically represented by an indicated hood screen. The components also shown in the drawing can be placed in the hood screen or in the extraction duct according to the relevant prior art. The air drawn in from the kitchen area by the fan 3 (arrow 10) passes through the hood screen first into a so-called grease filter 2 and can be discharged to the outside (A) as exhaust air (arrow 7) via a controllable switching device 4, or it is directed back into the kitchen (U) via an activated carbon filter 5 (arrow 6). The central control unit 9 of the device control system controls the fan 3 and a switching device 4 during operation, which, for example, can be used to select exhaust air, recirculation, or a mixed operation for the range hood via a conventional damper control.The hood screen of the extractor hood 1 symbolically indicates an odor sensor 8, which will be discussed in more detail below.

[0019] The function of the arrangement shown according to the invention is as follows: In normal operation, the extractor hood 1 can be configured for pure exhaust air operation, so that all process air is conveyed to the outside (A) after filtration through the grease filter 2. The switching device 4 is set so that the airflow can only occur in the direction of arrow 41. If an unpleasant odor occurs in the kitchen due to cooking or other odors, the user can operate a switching element 11 provided in the standard control unit of the extractor hood 1. The manually operated switching element 11, via the control unit 9 in conjunction with the switching device 4, causes the switch to recirculation mode (arrow 42).

[0020] Simultaneously, a setting stored in control unit 9 allows the fan 3 to be adjusted to a reduced fan speed compared to pure exhaust air operation. The user can then reverse this switch to recirculation mode by pressing the switch again and return to exhaust air mode.

[0021] On the other hand, it is also possible, through appropriate control means, to keep the recirculation mode active on a time-controlled basis and, after a preset time has elapsed, either to switch to the exhaust mode or to completely stop the operation of the extractor hood.

[0022] The switching device 4 can be controlled by the control unit 9 so that, instead of exhaust air operation, pure recirculation mode is activated, in which all process air is moved through the activated carbon filter 5 in the recirculation circuit. Alternatively, the air damper position in the switching device 4 can also be controlled by appropriate configuration of the control unit 9 so that the total airflow is split, resulting in a mixed operation with an exhaust air and a recirculation component. This automatically reduces the air flow rate remaining for recirculation operation, so that no disruptive noise can occur in the recirculation circuit.

[0023] According to the invention, the aforementioned operating method is also controlled by a noise sensor, which is not shown in detail here. The drawing shows, by way of example, a supplementary odor sensor 8 in the extractor hood 1, which, in conjunction with the control unit 9, controls the respective operating mode. This odor sensor 8, arranged, for example, in the area of ​​the hood's canopy, can detect unpleasant odors in the kitchen and thus trigger recirculation or mixed operation by sending a signal to the control unit 9.

[0024] Furthermore, it is also possible to install a noise sensor in the air duct system of the recirculation mode at a point where experience has shown that the highest noise emission is to be expected. When a predetermined noise level is reached, the noise sensor, in conjunction with control unit 9, can then reduce the fan or recirculation power.

[0025] The reduction of airflow in recirculation mode can be derived from empirically determined noise levels, which vary depending on the fan power used for the respective recirculation system. Through a control configuration of the electronic control unit 9, the fan power or the air damper in the switching device 4 can then be controlled so that recirculation operation occurs at an airflow level that prevents disturbing noises. Reference symbol list: 1 extractor hood 2 grease filters 3 blowers 4 Switching device 5 activated carbon filters 6 arrows for recirculated air (U) 7 Arrow for exhaust air (A) 8 Odor sensor 9 Control unit 10 arrows for drawn-in room air 11 Switching element 41 Arrow direction 42 Arrow

Claims

[1] Extractor hood (1) for operation in exhaust air and / or recirculation mode, comprising a control device (9) and an air guidance system, which includes a switching device (4) for carrying out exhaust air and recirculation modes, characterized by , that the extractor hood (1) has control and air guidance means which are configured and designed such that the extractor hood (1) can be operated in recirculation mode with a reduced air flow rate compared to exhaust air mode, wherein the reduction of the air flow rate in recirculation mode is achieved by a control and air guidance means in the extractor hood (1) The noise sensor is arranged and connected to the control unit (9). [2] Extractor hood (1) according to claim 1, characterized by, that the reduction of the air output in recirculation mode is carried out by the control device (9) in conjunction with a speed-controlled blower (3) or in conjunction with a switching device (4) with an electrically controlled air flap. [3] Extractor hood (1) according to claim 2, characterized by , that the control device (9) has control means by which the blower (3) or the switching device (4) can be controlled in such a way that the air output in recirculation mode can be adjusted to a value by which the noise generation in recirculation mode can be reduced. [4] Extractor hood (1) according to one of claims 1, 2 or 3, characterized by , that the recirculation mode can be activated by a manually operated switching element (11) arranged in the operating device of the extractor hood (1) in conjunction with the control device (9). [5] Extractor hood (1) according to one or more of claims 1 to 4 , characterized by, that an odor sensor (8) which is influenced by the room air is provided, which in conjunction with the control device (9) causes the activation of the recirculation mode. [6] Extractor hood (1) according to claim 5, characterized by , that the odor sensor (8) is located in the air inlet area of ​​the extractor hood (1). [7] Extractor hood (1) according to one or more of the preceding claims, characterized by , that the control unit (9) is configured in such a way and the switching device (4) is configured in such a way It is designed and controllable so that in mixed operation a recirculation component with a weakened airflow is established in the recirculation circuit, thereby avoiding disturbing noises. [8] Extractor hood (1) according to one or more of the preceding claims, characterized by , that an activated carbon filter (5) is arranged in the air duct for the recirculated air. [9] Method for operating a range hood (1) according to any one of the preceding claims 1 to 8, characterized by , that the recirculation operation is carried out with a reduced air performance compared to the exhaust air operation, whereby the reduction of the air performance is determined as a function of the noise development resulting in the recirculation system of the extractor hood (1) when the fan (3) is switched on. [10] Method for operating a range hood (1) according to claim 9; characterized by , that the activation of the recirculation mode is sensor-controlled or by a manually operated switching element (11), whereby the reduction of the air output is determined depending on noises empirically determined during the recirculation mode. [11] Method for operating a range hood (1) according to claim 10; characterized by, that the activation of the recirculation mode with a reduced air output is automatically carried out by an odor sensor (8) and / or a noise sensor connected to the control unit (9). [12] Method for operating a range hood (1) according to any one of claims 9 to 10; characterized by , that the switching device (4) can be controlled by the control unit (9) in such a way that in mixed operation the recirculation proportion is adjusted so that a weakened and noise-minimizing airflow is established in the recirculation circuit.

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