Extractor hood unit and method for operating an extractor hood unit

Abstract

Extraction unit (100, 200, 300) for ventilating a cooking environment (104), arranged and designed to extract cooking fumes (105) from the cooking environment (104) by means of a fan (110) of the extraction unit (100, 200, 300) and to convey them away from the cooking environment (104) via an exhaust air duct (115), with at least one first shut-off device (120, 220) which can be in a closed state and in an open state, wherein in the open state of the first shut-off device (120, 220) a vapor air stream (125) is guided through the exhaust air duct (115) via the blower (110) and in the closed state of the first shut-off device (120, 220) a cleaning air stream (135) is guided through the exhaust air duct (115), wherein the vapor airflow (125) is guided through a vapor opening (127) pointing towards the cooking environment (104) through a grease filter (130) in the area of ​​the vapor opening (127) and an odor filter (132) and wherein the cleaning airflow (135) is guided through at least one cleaning opening (137, 237, 237', 337) through a filter cascade (140, 140') for cleaning air, wherein the cleaning opening (137, 237, 237', 337) points in a different direction than the vapor opening (127), and wherein the vapor opening (127) is designed perpendicular to the cleaning opening (137, 237, 237', 337).

Description

[0001] The invention relates to a ventilation unit for ventilating a cooking environment and a method for operating a ventilation unit.

[0002] It is known to use extractor hoods for grease separation and odor removal. For this purpose, extractor hoods are equipped with, for example, grease filters and odor filters. It is also known to eliminate odors using an electrical separation method as an alternative to odor filters. Such odor removal devices are primarily used in recirculating systems, such as recirculating extractor hoods, which return the filtered air from a cooking environment back into the same room. This advantageously removes cooking odors and grease from the air within the room without requiring it to be extracted.

[0003] A generic extractor hood is known from publication DE 88 05 325 U1.

[0004] The object of the present invention is to provide an improved extractor hood, in particular an extractor hood with improved functionality for cleaning the room air.

[0005] According to the invention, this problem is solved by a fume hood unit with the features of claim 1 and a method with the features of claim 12. Advantageous embodiments and further developments of the invention will become apparent from the general description and from the dependent claims.

[0006] Within the scope of the invention, it was discovered that the extractor unit can be used not only for extracting cooking fumes but also for general room air purification. For this purpose, the invention provides for a separate purification airflow alongside the fume airflow. This purification airflow is separated from the fume airflow by at least one first sealing element. This eliminates the need for the air to be purified to pass through the grease filter within the fume airflow. This results in lower resistance and consequently a lower required suction power for the purification airflow to pass through the filter cascade.

[0007] The different directions in which the cleaning opening and the vapor opening are oriented are advantageous in preventing greasy deposits on the filter cascade within the cleaning airflow.

[0008] The use of a cleaning opening separate from the steam opening also allows a cleaning airflow that is not directed over the grease filter and / or the odor filter, so that cooking odors can be avoided during cleaning via the cleaning airflow.

[0009] The extractor fan according to the invention also allows for the cleaning of the room air at times when no airflow of cooking fumes is required, for example, when cooking is not currently taking place. In particular, the fan required for extracting cooking fumes can thus be used for an additional purpose, namely cleaning the room air. This eliminates the need to purchase additional electrical appliances.

[0010] Finally, purifying room air via a filter cascade is also advantageous because it avoids potentially harmful reaction products, such as those that can be produced by electrical separation methods. Furthermore, it eliminates the need for high-voltage technology, which is used in electrical separation methods.

[0011] The extractor hood is a device for extracting cooking fumes and can be located, for example, above the cooking area as a hood, such as mounted on a wall or ceiling, or integrated into a worktop or cooktop. Such different arrangements of the extractor hood are possible according to the invention. The purification of the room air via the filter cascade for recirculating extractor hoods is particularly advantageous according to the invention, as the purified air is returned to the room via the cleaning airflow, thus enabling effective purification of the room air.

[0012] The use of the at least one first shut-off device according to the invention can also include several first shut-off devices, wherein these are always designed such that, in the open state, they allow the flow of fume air through the exhaust air duct and, in the closed state, allow the flow of cleaning air through the exhaust air duct. The shut-off device is preferably a mechanical shut-off device, which can be adjusted between the open and closed states, for example, by means of an electrical control.

[0013] The exhaust air duct is an air guide section that directs the air to an outlet opening. This air guide section can be short, for example, just a few centimeters if the extractor hood is a recirculating extractor hood. Preferably, the extractor hood according to the invention has a common outlet opening for the exhaust air stream and the cleaning air stream.

[0014] The steam vent and the cleaning vent can be designed as a single, continuous opening or consist of several opening areas, such as grid-shaped or slot-shaped openings.

[0015] According to the invention, the filter cascade is a combination of at least two filters through which the cleaning airflow is passed. Preferably, no further objects are arranged between the at least two filters; in particular, the at least two filters are preferably arranged directly one after the other.

[0016] Preferred embodiments of the extractor hood according to the invention are described below.

[0017] Preferably, the flow of fumes is blocked by the first sealing element when it is closed, and in particular, blocked airtight. This ensures that no greasy fumes reach the filter cascades.

[0018] Preferably, the cleaning airflow is blocked by the first blocking device when it is open, and in particular, blocked airtight. This ensures that no additional ambient air is drawn into the exhaust air duct during cooking, thus reducing the fan power available for extracting the cooking fumes. Particularly preferred in this embodiment is that the fume airflow is blocked by the first blocking device when it is closed, and in particular, blocked airtight. This ensures that the fume airflow and the cleaning airflow are airtightly separated.

[0019] In a particularly preferred embodiment, the exhaust air extraction unit has at least two shut-off devices, wherein, in addition to the first shut-off device, a second shut-off device is arranged and configured such that, in an open state, it allows the flow of cleaning air through the exhaust air duct and, in a closed state, blocks the flow of cleaning air through the exhaust air duct. The preferred provision of two shut-off devices allows for a particularly simple and robust design of each shut-off device, since each shut-off device only blocks or opens a section of an air duct. This allows the exhaust air extraction unit according to the invention to be implemented using a single, cost-effective shut-off device.

[0020] In a variant of the preceding embodiment, the first shut-off device is connected to the second shut-off device such that the first shut-off device is in the open state when the second shut-off device is in the closed state, and the first shut-off device is in the closed state when the second shut-off device is in the open state. Such a connection between the two shut-off devices can be achieved via a mechanical connection and / or an electronic connection and / or via the control logic of an electronic control unit. This type of connection advantageously enables reliable separation between the fume airflow and the cleaning airflow.

[0021] In a preferred embodiment, the extractor hood according to the invention has exactly one blower, through which the fume airflow or the cleaning airflow is drawn in, depending on the state of the at least one first shut-off means.

[0022] In another embodiment, the filter cascade is arranged in the area of ​​the cleaning opening. This allows for particularly effective cleaning of all the air drawn in through the cleaning opening via the filter cascade. Furthermore, this location of the filter cascade allows for particularly easy replacement of the filter cascade should individual or all filters within it need to be replaced.

[0023] In a preferred embodiment, the filter cascade comprises at least two filters from the following group: coarse dust filters, fine dust filters, HEPA filters, and odor filters. Such filters are known to those skilled in the art in various designs, so details of possible designs of such filters will not be discussed below. In principle, such filters can be manufactured in large quantities due to their diverse applications, making them advantageously available for the exhaust air extraction unit according to the invention.

[0024] In another preferred embodiment, the fume extraction opening is spaced apart from the cleaning opening. This prevents greasy fumes from passing through the cleaning opening and thus, for example, contaminating the filter cascade. Preferably, the fume extraction opening is located at least 10 cm, particularly at least 20 cm, and most preferably at least 30 cm away from the cleaning opening on the extractor hood. Particularly preferably, the cleaning opening and the fume extraction opening are located on opposite sides of an extractor hood screen of the extractor hood. The fume extraction opening faces the cooking area and points in a direction below the extractor hood screen, whereas the cleaning opening is located above the extractor hood screen and can therefore also draw in room air from outside the immediate cooking area.

[0025] According to the invention, the steam vent is essentially perpendicular to the cleaning opening. This ensures that little or no cooking steam is drawn in through the cleaning opening. Furthermore, it prevents rising air from cooking from being drawn through the cleaning opening without being drawn in.

[0026] In an advantageous embodiment, the first and / or the second shut-off device is formed by a flap, a number of lamellar flaps, a valve, a tap, a slide valve, an orifice, and / or a louver. Such shut-off devices are known to those skilled in the art in hydrodynamics, so details of such implementations will only be discussed within the context of the exemplary embodiments illustrated in the figures. Advantageously, known implementations can be used when employing such shut-off devices, thus enabling cost-effective manufacturing.

[0027] In a particularly advantageous embodiment, the respective state of the first and / or second shut-off device is controlled by a control unit of the extractor hood. Using a control unit ensures centralized control of the airflow within the extractor hood. For example, the control unit can receive an input via an input interface indicating the desired state of the first and / or second shut-off device. Such an input can be made directly by the user, for example, via a button, touchscreen, rotary dial, or the like. Alternatively or additionally, such an input can be made, for example, via a wireless connection to an external device such as a smartphone, tablet, notebook, or the like.

[0028] In a particularly preferred embodiment of the preceding design, the extractor hood controls the activation of a cleaning airflow based on an output value from an air sensor of the extractor hood. Such control enables automatic activation of the cleaning airflow when the air sensor indicates the need for such cleaning. For this purpose, the air sensor can be, for example, a VOC sensor or the like. In particular, the air sensor can indicate via its output value that a component of the room air, which indicates air pollution, especially one considered hazardous to health, has reached a predetermined threshold. Preferably, activation of the cleaning airflow is triggered via the at least one shut-off device if the output value indicates that a predetermined threshold has been reached.Preferably, the control unit enables the comparison of the output value with the predetermined threshold value. Preferably, the control unit is configured to receive the output value from the air sensor. This allows the control unit to control the first and / or the second shut-off device depending on the output value.

[0029] In a preferred example of the preceding variants, the control unit checks, before activating the cleaning airflow, whether a steam airflow is currently present, intended for extracting cooking fumes. If a steam airflow is present, the activation of the cleaning airflow is preferably postponed, in particular for a predetermined time interval. This ensures that the cooking fumes, which pose an immediate threat to air quality, are reliably extracted.

[0030] In a preferred version, a pulsed cleaning mode is provided for the automatic activation of the cleaning airflow based on the output value of the air sensor. This keeps the noise level as low as possible over time.

[0031] Preferably, an automatically activated cleaning airflow is deactivated again if the output value of the air sensor falls below a predetermined deactivation threshold. This avoids the need for a user to actively interact with the extractor hood during automated operation.

[0032] In a further embodiment of the extractor hood, the first and / or the second shut-off device can be manually operated. Such manual operation, via a mechanical means, an electronic user interface, or the like, allows manual intervention in the operation of the extractor hood. Preferably, actuating the first shut-off device simultaneously actuates the second shut-off device, and vice versa. This ensures that the exhaust airflow and the cleaning airflow are kept separate.

[0033] In a particularly preferred embodiment, the extractor hood according to the invention is designed as an extractor hood, in particular as a recirculating extractor hood. Especially in the case of a recirculating extractor hood, the cleaning of the room air via the cleaning airflow can be used to effectively improve the quality of the room air. Furthermore, the use of an extractor hood, compared to a cooktop extractor, allows for advantageous air dynamics for drawing in the air to be cleaned and / or for extracting the cooking fumes.

[0034] The extractor hood according to the invention can also be controlled by an external device. For this purpose, the extractor hood includes, for example, a receiver module for receiving a control signal provided by an external device. The external device can be, for example, a smartphone, a tablet, a notebook, or the like. User control can be enabled, for example, via a user application provided for the extractor hood.

[0035] According to a second aspect, a method for operating a range hood is proposed to solve the aforementioned problem. The method according to the invention comprises the following steps: - Providing an initial barrier device that can be in a closed state and in an open state; - Extraction of cooking fumes from the cooking environment through a fume opening and routing these cooking fumes away from the cooking environment through a grease filter, if the first sealing device is in an open state; - Extraction of room air through a cleaning opening and routing this room air away from the cooking environment through a filter cascade to clean the air if the first shut-off device is in a closed state, with the cleaning opening pointing in a different direction than the steam opening.

[0036] The method according to the second aspect of the invention is carried out by the extractor hood according to the first aspect of the invention, so that it shares all the advantages of this extractor hood. In particular, the method according to the invention enables the extraction and purification of room air by the extractor hood, thereby providing the extractor hood with additional functionality, especially when no cooking fumes currently need to be extracted.

[0037] After the first sealing device has been provided in the first step of the procedure, the order of the two further steps, i.e. the extraction of cooking fumes or the extraction of room air, is not predetermined and depends on a specific set of circumstances.

[0038] In an advantageous embodiment, the method according to the second aspect of the invention is extended by the following two process steps: - Measuring air quality and providing an output value indicating the air quality; and - Control of the first and / or at least one further barrier device based on the output value.

[0039] These additional process steps allow for automated cleaning of the room air depending on the output value. This enables automated room air cleaning independent of user interaction with the extractor hood and independent of any cooking processes.

[0040] The invention will now be explained in more detail with reference to advantageous embodiments schematically illustrated in the figures. These show, in detail: Fig. 1a, Fig. 1b a schematic representation of a first embodiment of a cooker hood unit according to a first aspect of the invention, wherein a first shut-off means in the open state ( Fig. 1a) and in the closed state ( Fig. 1b) is shown; Fig. 2a, Fig. 2b a schematic representation of a second embodiment of the extractor hood unit according to the first aspect of the invention, wherein the first shut-off device is in the open state ( Fig. 2a) and in the closed state ( Fig. 2b) is shown; Fig. 3a, Fig. 3b a schematic representation of a third embodiment of the extractor hood unit according to the first aspect of the invention, wherein the first shut-off device is in the open state ( Fig. 3a) and in the closed state ( Fig. 3b) is shown; and Fig. 4 a flowchart of an embodiment of a method according to a second aspect of the invention.

[0041] Fig. 1a and Fig. Figure 1b shows a schematic representation of a first embodiment of a cooker hood unit 100 according to a first aspect of the invention, wherein a first shut-off device 120 is in the open state ( Fig. 1a) and in the closed state ( Fig. 1b) is shown.

[0042] In the illustrated embodiment, the extractor unit 100 is designed as an extractor hood. It is positioned above a cooktop (not shown) to effectively extract cooking fumes 105. Furthermore, the extractor unit 100 is a recirculating extractor hood, meaning it returns the extracted air to the room.

[0043] The extractor hood 100 is arranged above the cooktop for ventilating a cooking environment 104. It is designed and configured to extract cooking fumes from the cooking environment 104 by means of a fan 110 of the extractor hood 100 and to convey them away from the cooking environment 104 via an exhaust air duct 115. For this purpose, the extractor hood 100 according to the invention has at least one shut-off device 120, which can be in a closed state and in an open state.

[0044] In the Fig. In the open state of the first shut-off device 120 shown in Figure 1a, a vapor airflow 125 is guided through the exhaust air duct 115 via the blower 110. This vapor airflow 125 is guided through a grease filter 130 in the area of ​​the vapor opening 127 and an odor filter 132 via a vapor opening 127 facing the cooking environment 104. In the Fig. In the closed state of the first shut-off device 120 shown in 1b, a cleaning airflow 135 is directed through the exhaust air duct 115 via the blower 110. This cleaning airflow 135 is directed through at least one cleaning opening 137 and a filter cascade 140 for air purification, the cleaning opening 137 pointing in a different direction than the fume opening 127.

[0045] In the illustrated embodiment, the first shut-off device 120 is formed by a flap movably mounted at the attachment point 122. In the illustrated embodiment, this flap can be moved into the open or closed position by a manual control mechanism (not shown). Alternatively or additionally, a control unit can change the state of the first shut-off device 120, as is the case, for example, in the Fig. 2a, Fig. 2b is shown.

[0046] In the illustrated embodiment, both the fume airflow 125 and the cleaning airflow 135 are drawn in via the blower 110 and directed to a common outlet opening 117 at the end of the exhaust air duct 115. In alternative embodiments of the invention (not shown), different blowers and / or different outlet openings are provided for the extractor hood.

[0047] In this case, the filter cascade 140 is arranged directly at the cleaning opening 137, making it particularly easy to change the filter cascade 140 and / or individual filters of the filter cascade 140.

[0048] The filter cascade 140 consists of an odor filter and a fine dust filter. Preferably, the filter cascade according to the invention comprises at least two filters from the following group of filters: coarse dust filter, fine dust filter, suspended particulate filter, odor filter.

[0049] The odor filter 132 and grease filter 130, located within the vapor airflow 125, are positioned directly at the vapor opening 127. This allows for easy removal for cleaning the grease filter 130 and / or replacing the odor filter 132.

[0050] The cleaning opening 137 is spaced apart from the fume opening 127 and is oriented essentially perpendicular to it. This means that a surface normal of the fume opening 127 is essentially perpendicular to a surface normal of the cleaning opening 137. In this case, the fume opening 127 is located on the underside of the extractor hood 100, specifically on the underside of an extractor hood screen of the extractor hood 100. The cleaning opening 137, on the other hand, is located laterally on the exhaust air duct 115. This prevents the cleaning airflow 135 from passing through the grease filter 130 and the odor filter 132, thus preventing cooking odors from being carried back into the surrounding room.

[0051] Fig. 2a and Fig. Figure 2b shows a schematic representation of a second embodiment of the extractor unit 200 according to the first aspect of the invention, wherein the first shut-off device 220 is in the open state ( Fig. 2a) and in the closed state ( Fig. 2b) is shown.

[0052] The extractor hood unit 200 differs from the one in Fig. The exhaust air unit 100 shown in Figure 1 is characterized, among other things, by the fact that, in addition to the first shut-off device 220, a second shut-off device 250 is provided for controlling the airflows 125 and 135 within the exhaust air unit 200. The second shut-off device 250 is arranged and designed such that, in an open state, it allows the cleaning airflow 135 through the exhaust air duct 115 and, in a closed state, it blocks the cleaning airflow 135 through the exhaust air duct 115. The second shut-off device 250 is connected to the first shut-off device 220 in such a way that the first shut-off device 220 is in the open state when the second shut-off device 250 is in the closed state, and the first shut-off device 220 is in the closed state when the second shut-off device 250 is in the open state. This connection can be made via a mechanical linkage between the first and second shut-off devices.In the illustrated embodiment, at least additionally, the first shut-off device 220 and / or the second shut-off device 250 are controlled by a control unit 260 of the extractor hood unit 200. The control unit 260 is functionally connected to the first and / or second shut-off device 220, 250 and thus enables control of the state of these shut-off devices 220, 250.

[0053] Activation of the fume airflow 125 is preferably permitted by an initial position of the shut-off devices 220, 250. This allows the extraction of fumes by the extractor unit 200 to be achieved particularly quickly during a cooking process.

[0054] The first and / or the second shut-off device 220, 250 are formed in this case by a number of lamellar flaps. Alternatively or additionally to the shut-off devices shown, these can also be formed by a valve, a tap, a gate valve, an orifice, a louver, and / or a combination thereof. In particular, the first shut-off device can be designed differently from the second shut-off device.

[0055] Unlike the extractor hood unit 100 from Fig. Figure 1 shows that the illustrated extractor hood unit 200 also has several cleaning openings 237, 237'. Each of these cleaning openings has a corresponding filter cascade 140, 140'. Alternatively, the extractor hood unit 200 can also have more than two cleaning openings, such as four. Alternatively, the extractor hood unit according to the invention can also have a circumferential annular cleaning opening, so that the opening is not a hole-shaped recess, but, for example, an annular gap in a cylindrical shell.

[0056] Fig. 3a and Fig. Figure 3b shows a schematic representation of a third embodiment of the extractor unit 300 according to the first aspect of the invention, wherein the first shut-off device is in the open state ( Fig. 3a) and in the closed state ( Fig. 3b) is shown.

[0057] The extractor hood unit 300 differs from the one in Fig. The exhaust air unit 200 shown in Figure 2 is equipped, among other things, with an air sensor 370 arranged on the exhaust air unit 300. This sensor is configured to provide an output value 372 that indicates the air quality within the surrounding space. For this purpose, the concentration of a substance to be avoided in the air can be determined, for example. Examples of such substances are pollutants whose concentration is determined, for example, by the air sensor 370, such as particulate matter, nitrogen dioxide, sulfur dioxide, and / or carbon monoxide. As soon as the output value 372 reaches a predetermined threshold, the cleaning airflow 135 is activated, for example, to enable effective air purification. For this purpose, the output value 372 is transmitted to the control unit 360. Preferably, the cleaning airflow 135 is only activated if there is currently no exhaust airflow 125.This allows the steam airflow 125 to be prioritized during a cooking process. The output value is preferably sent to the control unit 360. The control unit 360 then controls the shut-off devices 220 and 250 according to predetermined control steps. The shut-off devices 220 and 250 of the extractor hood 300 are identical to those described in [reference missing]. Fig. 2 barrier devices shown.

[0058] Finally, the airflow within the 300 extractor hood unit also differs from that in Fig. 2. The extractor hood unit 200 is shown. The cleaning opening 337 is located on the rear side of the extractor hood screen of the extractor hood unit 300. The filter cascade 140 is in turn arranged directly at two outlet openings 317, 317', 318 provided for the cleaning airflow 135. In this embodiment, the shut-off devices 220, 250 are also arranged in the area of ​​the outlet openings 317, 317', 318, wherein the outlet opening 318 provided for the fume air stream 125 has a different orientation than the two outlet openings 317, 317' of the cleaning air stream 135. The shut-off devices 220, 250 ensure that the air from the fume air stream 125, which is contaminated with fumes and odors, is not directed through the filter cascade 140.Furthermore, the cleaning opening 337, which is separate from the fume opening 127 under the extractor hood, ensures that the cleaning airflow 135 is primarily not directed through the grease filter 130 and the odor filter 132. Therefore, the advantageous airflow shown supports the cleaning of the surrounding room air without additionally burdening it with odors. This enables, as in the previous embodiments, a combination of fume extraction and air purification that entails virtually no disadvantages with regard to odor pollution. As in . Fig. As shown in Figure 3b, unlike the extractor units 100 and 200 from the preceding embodiments, air is also drawn in through the grease filter 130, but due to the higher flow resistance, the proportion of air drawn in through this filter is very small. In an advantageous embodiment, an odor filter located in the area of ​​the outlet opening 318 of the fume airflow 125 prevents the air from the cleaning airflow 135 from coming into contact with this odor filter and thus from being contaminated with cooking odors. Alternatively, the odor filter can also be arranged upstream of the fan 110 for both airflows 125 and 135.

[0059] In embodiments not shown, more than two outlet openings are provided for the cleaning airflow.

[0060] Fig. Figure 4 shows a flowchart of an embodiment of a method 400 according to a second aspect of the invention.

[0061] The inventive method 400 is designed for operating a fume hood unit and comprises the steps described below: A first step 410 includes providing an initial barrier device, which can be in a closed state and in an open state.

[0062] A subsequent step 420 involves extracting cooking fumes from the cooking environment through a fume opening and directing these cooking fumes away from the cooking environment through a grease filter if the first shut-off device is in an open state.

[0063] A further step 430 includes extracting room air through a cleaning opening and directing this room air away from the cooking environment through a filter cascade to clean the air if the first shut-off device is in a closed state.

[0064] According to the invention, in all steps 410, 420, 430 the cleaning opening points in a different direction than the steam opening.

[0065] The first step 410, i.e., the provision of the first barrier device, always occurs before the subsequent steps 420 and 430. The two further steps 420 and 430 do not run in parallel, but can be performed in any order and with any frequency. In particular, one of the two steps 420 or 430 can be performed multiple times before the other of the two steps 420 or 430 is performed again.

[0066] In an advantageous variant of this embodiment (not shown), the method also includes the following two steps: - Measuring air quality and providing an output value indicating the air quality; and - Control of the first and / or at least one further barrier device based on the output value.

[0067] These two steps enable the automatic activation of at least step 430, i.e., the extraction of room air. This allows, for example, automated and effective room air purification as soon as the output value indicates that this would be beneficial given the current air quality. For instance, room air extraction according to step 430 can occur as soon as the output value reaches a predetermined threshold. Reference symbol list 100, 200, 300 extractor hood unit 104 Cooking environment 105 cooking fumes 110 blowers 115 Exhaust air duct 117, 317, 317', 318 Exit opening 120, 220 first barrier 122 Mounting point 125 steam airflow 127 Vapor opening 130 grease filters 132 odor filters 135 Cleaning airflow 137, 237, 237', 337 Cleaning opening 140, 140' Filter cascade 250 second barrier device 260, 360 control unit 370 air sensor 372 Issue value 400 procedures 410, 420, 430 Procedural steps

Claims

[1] Extraction unit (100, 200, 300) for ventilating a cooking environment (104), arranged and designed to extract cooking fumes (105) from the cooking environment (104) by means of a fan (110) of the extraction unit (100, 200, 300) and to convey them away from the cooking environment (104) via an exhaust air duct (115), with at least one first shut-off device (120, 220) which can be in a closed state and in an open state, wherein in the open state of the first shut-off device (120, 220) a vapor air stream (125) is guided through the exhaust air duct (115) via the blower (110) and in the closed state of the first shut-off device (120, 220) a cleaning air stream (135) is guided through the exhaust air duct (115), wherein the vapor airflow (125) is guided through a vapor opening (127) pointing towards the cooking environment (104) through a grease filter (130) in the area of ​​the vapor opening (127) and an odor filter (132) and wherein the cleaning airflow (135) is guided through at least one cleaning opening (137, 237, 237', 337) through a filter cascade (140, 140') for cleaning air, wherein the cleaning opening (137, 237, 237', 337) points in a different direction than the vapor opening (127), and wherein the vapor opening (127) is designed perpendicular to the cleaning opening (137, 237, 237', 337). [2] Extraction unit (100, 200, 300) according to claim 1 with at least two shut-off means (120, 220, 250), wherein in addition to the first shut-off means (120, 220) a second shut-off means (250) is arranged and designed such that in an open state it allows the cleaning air flow (135) through the exhaust air duct (115) and in a closed state it blocks the cleaning air flow (135) through the exhaust air duct (115). [3] Extraction unit (100, 200, 300) according to claim 2, wherein the first shut-off means (120, 220) is connected to the second shut-off means (250) such that the first shut-off means (120, 220) is in the open state if the second shut-off means (250) is in the closed state, and that the first shut-off means (120, 220) is in the closed state if the second shut-off means (250) is in the open state. [4] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the filter cascade (140, 140') is arranged in the area of ​​the cleaning opening (137, 237, 237', 337). [5] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the filter cascade (140, 140') comprises at least two filters from the following group of filters: coarse dust filter, fine dust filter, particulate filter, odor filter. [6] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the vapor opening (127) is spaced apart from the cleaning opening (137, 237, 237', 337). [7] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the first and / or the second shut-off means (120, 220, 250) is formed by a flap, a number of louvered flaps, a valve, a tap, a slide, a baffle and / or a louver. [8] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the respective state of the first shut-off means (120, 220) and / or the second shut-off means (250) is controlled via a control unit (260) of the extraction unit (100, 200, 300). [9] Extractor unit (100, 200, 300) according to claim 8, wherein the extractor unit (100, 200, 300) controls the activation of a cleaning airflow (135) by the extractor unit (100, 200, 300) based on an output value (372) of an air sensor (370) of the extractor unit (100, 200, 300). [10] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the first shut-off means (120, 220) and / or the second shut-off means (250) can be operated manually. [11] Extraction unit (100, 200, 300) according to at least one of the preceding claims, wherein the extraction unit (100, 200, 300) is designed as an extractor hood, in particular as a recirculating extractor hood. [12] Method (400) for operating a range hood (100, 200, 300) comprising the steps: - Providing a first barrier device (120, 220) which can be in a closed state and in an open state; - Extraction of cooking fumes (105) from the cooking environment (104) through a fume opening (127) and directing these cooking fumes (105) away from the cooking environment (104) through a grease filter (130) if the first shut-off device (120, 220) is in the open state; - Extraction of room air through a cleaning opening (137, 237, 237', 337) and directing this room air away from the cooking environment (104) through a filter cascade (140, 140') to clean the air if the first shut-off device (120, 220) is in the closed state, wherein the cleaning opening (137, 237, 237', 337) points in a different direction than the fume opening (127), and wherein the fume opening (127) is designed perpendicular to the cleaning opening (137, 237, 237', 337). [13] Method (400) according to claim 12, further comprising the steps - Measuring air quality and providing an output value indicating air quality (372); and - Control of the first and / or at least one further shut-off device (120, 220, 250) based on the output value (372).

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