EP3045824B1 - Device for drawing off exhaust air of a cooker hob - Google Patents

Description

The invention relates to a device for extracting exhaust air from a hob.

To remove exhaust air and odors from kitchens, extractor hoods are used with which the cooking vapors and the associated odors can be extracted. Such extractor hoods have a fan to generate a flow over the hob. Basically, they can be divided into two categories.

With the so-called exhaust air extractors, the exhaust air is led to the outside via a pipe or hose line from an exhaust air outlet of the extractor and thus withdrawn from the room in which the hob and the extractor are located. The exhaust air polluted with odors is released into the atmosphere outside the building. However, the extraction of warm air from a room leads to an increased energy requirement, since the fresh air that replaces the extracted exhaust air has to be reheated.

In the case of circulating air extractors, on the other hand, the exhaust air is fed back into the room. Here the exhaust air must be cleaned of the adhering smells. For this purpose, a carbon filter is usually provided, which must either be replaced at certain intervals or regenerated. Both types of extractor hoods usually have a separation device for separating solid and liquid components of the exhaust air. The dirt particles can be separated off by grease filters, which in particular hold back the grease droplets contained. Such grease filters can be easily removed and cleaned in a dishwasher.

Separation devices have also already become known in which the particles are separated out by means of suitable guidance of the air flow. In these separation devices, the exhaust air flow is deflected in such a way that the particles contained are pressed outwards and separated on the inner wall of the exhaust air duct.

Both separation devices remove most of the solid and liquid components contained in the exhaust air, such as fat droplets, dirt particles and condensed water, before the Exhaust air enters the fan. This will keep the fan clean and functional. In the case of the exhaust air extractors, the separation devices also prevent exhaust air that is currently laden with fat from getting outside and the fats contained being deposited on the outer wall, for example.

In the case of circulating air extractors, it is particularly important to prevent the carbon filter from becoming loaded with grease. The exchange of the carbon filters must be done faster, the more fat is still contained in the exhaust air after the separation device.

It is therefore important to aim for the highest possible degree of grease separation in all extractor hoods.

The EP 1 532 907 A1 describes an electric smokeless roaster that is able to dispense with pipes installed inside or outside a retail store and almost completely eliminate the generation of harmful gases. The roaster comprises an electric heating device 2 installed in the upper area of a housing 1, a water pan 6 installed on the lower area of the heating device 2, a grill 9 which is arranged above the heating device 2, a table 7 which is installed on the surface of the case 1, and an opening in a portion of the case surface that corresponds to the grill 9. Furthermore, the grill comprises a suction device 10 which is installed around the grill 9 and has suction openings for sucking out air around the grill; an electric dust collector 30 installed in the case and purifying air sucked by the suction device 10; and a deodorizing device 50 installed in the case and serving to decompose odorous substances contained in the air cleaned by the dust collector 30 and to take the decomposed odorous substances out of the case.

The DE 10 2005 004 692 A1 describes an extractor hood 2 with a fan and an air duct 4, which is arranged between a suction opening 8 and an exhaust opening 10 that can be connected to an exhaust air pipe 12. In the course of the air duct 4, in the area of the blow-out opening 10 and / or in the exhaust air pipe 12, a filter 14 is arranged through which at least part of the air flow that can be conveyed through the air duct 4 can be blown out.

The EP 2 772 695 A2 describes an extractor device with edge extraction. The device comprises at least one slot-shaped air intake opening 12, which runs along an edge of a central air-impermeable cover plate 13, a hood screen 12 with at least one central air-permeable grease filter 123 which closes off an exhaust shaft or chimney 11. At least A central area of the grease filter 123 and the hood screen 12 are shielded from a hotplate during operation by the cover plate 13 and connected to the slit-shaped intake opening 121 through an air duct 125, the inner boundary surfaces of which are air-impermeable surfaces of the hood screen and the cover plate. The inner boundary surfaces are shaped in such a way that the boundary surfaces opposite the gap-shaped intake opening 121 deflect an air flow entering through the gap-shaped intake opening by at least 45 degrees.

The U.S. 4,962,694 A describes a cartridge for a grill exhaust system with a fan device which removes exhaust air flows and particles generated by cooking from the hob provided with openings. The cartridge has a main frame defining an outlet plenum and a pair of inwardly facing and opposing compartments. A removable and replaceable flow divider cartridge can be inserted into the plenum below the cooking surface and comprises a cartridge body which comprises a flow divider device within the cartridge body in order to induce a wave movement in the exhaust air flow so that particles are separated from the exhaust air flow while the fumes from the hob down through the air compartments.

The CN 101 126 516 A describes an extractor hood which has a support member which is arranged in the central opening of a slim housing with downwardly directed rectangular openings. The support member bridges two opposite edges of the opening and depends on a cover plate of the housing. The extractor hood has a central cover which is removable and there is clearance between the central cover and the edge of the downward opening. Perforated panels are formed between the central cover and the other opposite edges of the opening. Furthermore, the support member is equipped with lighting and the central cover is provided with an oil collecting device which collects the oil dripping from the perforated plate.

The DE 20 2013 005 303 U1 describes an optimized hob with a device for extracting cooking vapors in a direction vertically below the plane of the hob, with a recess that is round or oval or square in plan view is provided for the device for extracting cooking vapors in the area of the geometric centroid of the hob, see above that the surfaces located on both sides and to the rear of the hob on the worktop carrying the hob can be used without restriction for storage purposes or the like.

The invention is based on the object of designing a device for extracting exhaust air over a hob according to the preamble of claim 1 so that the degree of separation, in particular of fats contained in the exhaust air, can be increased.

The object is achieved according to the invention by a device for extracting exhaust air from a hob with the features of claim 1.

It has been found that the first separation device works particularly efficiently when high flow velocities are reached. At such high flow velocities, even smaller and lighter particles have a sufficiently great inertia that they cannot follow the deflected exhaust air completely, but instead maintain their straight trajectory for longer or adopt a trajectory with less curvature. In this way, they reach a deflection element responsible for deflecting the exhaust air and are deposited thereon. At a lower flow velocity, only slightly larger particles behave in this way. Very small particles, on the other hand, quickly adapt their trajectory to the trajectory of the deflected exhaust air and are carried away.

The opposite is the case with the flow through the filter. The highest degree of separation is achieved here at low flow speeds. At high flow velocities, the fat droplets contained come into contact with the filter fabric, but are often swept away again by the fast exhaust air before they can aggregate into larger and heavier droplets. It has been found that these filters work most effectively at low flow rates.

By combining the first separation device in connection with a previous acceleration of the exhaust air and the second separation device in connection with a deceleration of the exhaust air, an extractor hood can now be operated for the first time in all performance levels with a high degree of separation. It is therefore irrelevant whether the fan is operated with high or low power. The same high degree of separation is achieved for every flow velocity of the exhaust air.

Further details and advantages of the invention emerge from the subclaims.

According to the invention, the at least one exhaust air inlet is provided next to the hob. With such extractors, the exhaust air is no longer extracted upwards, but downwards. The This way, the view through the kitchen - especially when using a kitchen block - is uninterrupted. Since a large exhaust air inlet cannot be used here and the exhaust air is already experiencing a first acceleration through the gap-shaped exhaust air inlet, the first separation device behind the exhaust air inlet and the exhaust air duct which accelerates the exhaust air again can be used particularly effectively.

For example, glass fibers or synthetic materials can be used for the filter. Such filters can only be used as single-use filters and have to be replaced frequently. The at least one filter through which the exhaust air flows is therefore advantageously made of metal. In particular, stainless steel or aluminum is used here. Such filters are corrosion-resistant and cannot be attacked by the fatty acids contained in the exhaust air. Even if the filter is cleaned in a dishwasher, the filter cannot be damaged.

The deflection of the exhaust air in the first separation device should be selected to be as large as possible, so that a high degree of separation is achieved. On the other hand, the deflection must not be too great, since otherwise the flow resistance would become too great. A deflection element is therefore provided which has an angle between 10 and 30 ° to the horizontal. In particular, an angle between 20 and 22 ° has proven to be particularly advantageous. It has been found that this inclination of the deflecting element is sufficient so that separated and accumulated fat droplets can run down to the free edge of the deflecting element and drip off from this edge.

The highest possible flow velocity is required for the separation of particles in the first separation device. When flowing through the at least one gap-shaped exhaust air inlet, the exhaust air is already accelerated, but this is not yet sufficient. The flow cross-section in front of the first separation device is particularly advantageously reduced to 40 to 60% of the flow cross-section behind the at least one exhaust air inlet. The first exhaust air duct is consequently constructed in such a way that the flow cross-section is reduced as continuously as possible between the exhaust air inlet and the first separation device. Before the deflection, the exhaust air should have a flow speed of at least 8 m / s - at least at the highest power level of the fan.

Since very small fat droplets in particular are deposited mainly via the filter when the fan is running at a low power level, a not inconsiderable amount of fat accumulates here over time. To ensure that the filter is only cleaned at longer intervals the filter should be arranged so that accumulated fat can drain off. The at least one filter is therefore arranged vertically. In this position, not only does the accumulated fat run off best, but the largest flow cross-section can also be realized.

The fat running off the deflection element and the filter must not drip onto the kitchen floor or into a base unit. A collecting pan is therefore advantageously provided under the deflection element and the at least one filter. This drip pan is designed so that it can hold a larger amount of fat without overflowing. A level sensor can also be provided which generates an alarm when the highest fill level is reached.

The drip tray can be designed so that it can be removed and emptied separately. However, the exhaust air duct, the first separating device, the second separating device and the collecting pan are particularly advantageously constructed as a removable module. In this way, a single action is only necessary at longer intervals to keep the extractor in a neat and functional condition. The entire module can be placed in a dishwasher and cleaned there in a simple manner.

The device according to the invention can be used both as an exhaust air vent and as a circulating air vent. The exhaust air outlet therefore either guides the exhaust air back into the room via an odor filter or directs it outside via another exhaust air duct. Of course, it can also be used as an exhaust air vent and as a circulating air vent. A changeover switch is provided for this purpose. In this way, e.g. B. summer-winter switching possible, whereby the extractor can be operated in winter as a circulating air extractor and in summer as an exhaust air extractor. Switching between the operating modes can be done manually but also automatically, for example, depending on the outside temperature.

Control elements are often attached to the front edge of the hob as touch sensors. In the case of an exhaust air inlet on the front of the hob, these control elements would get dirty very quickly and make regulation or switch-off difficult or even impossible. There is therefore at least one exhaust air inlet behind the hob or at least one exhaust air inlet each to the left and right of the hob. In the case of a conventional hob with two rows of cooking zones one behind the other, at least two exhaust air inlets at the side are used. In the case of a one-row arrangement of several adjacent cooking zones, on the other hand, at least one exhaust air inlet behind the hob is advantageous.

There are many different hobs available on the market that meet a wide variety of requirements. These hobs should also be usable in connection with the device according to the invention. A frame is therefore provided in which a hob with standard dimensions can be used. In this way, the device according to the invention can even be retrofitted in an existing kitchen. The at least one exhaust air inlet can be integrated into the frame.

In order to be able to save energy, it is desirable to operate the fan with the lowest possible power. The necessary suction effect should be retained. It is therefore particularly advantageous to provide several individually openable and individually closable exhaust air inlets. In this way, it is possible to always open only the required exhaust air inlets and, accordingly, to require less fan power.

Further details and advantages of the invention emerge from the description of exemplary embodiments, which are explained in detail with reference to the drawing.

Fig. 1

eine perspektivische Ansicht eines ersten Ausführungsbeispiels eines erfindungsgemäßen Dunstabzugs,

Fig. 2

eine Schnittdarstellung des oberen Teils des Ausführungsbeispiels nach Fig. 1,

Fig. 3

eine Aufsicht auf ein zweites Ausführungsbeispiel des erfindungsgemäßen Dunstabzugs in eingebautem Zustand,

Fig. 4

eine schematische Darstellung der Abluftführung in dem ersten Ausführungsbeispiel und

Fig. 5

eine Darstellung der Strömungsquerschnitte bis zur ersten Abscheideeinrichtung anhand des ersten Ausführungsbeispiels.

It shows:

Fig. 1

a perspective view of a first embodiment of an extractor according to the invention,

Fig. 2

a sectional view of the upper part of the embodiment according to Fig. 1 ,

Fig. 3

a plan view of a second embodiment of the extractor according to the invention in the installed state,

Fig. 4

a schematic representation of the exhaust air duct in the first embodiment and

Fig. 5

a representation of the flow cross-sections up to the first separation device on the basis of the first embodiment.

In Fig. 1 shows an embodiment of the extractor 1 according to the invention without a built-in hob. Only the hob opening 12 is visible, into which a standard hob can be inserted. The frame 2 of the extractor hood 1 can have different sizes, the dimensions each being adapted to a specific standard size of a hob. The frame 2 can be inserted into a worktop in the usual way and fastened to it via the installation brackets 3.

The frame 2 has on both sides, in addition to the hob opening 12, an exhaust air inlet designed as a suction gap 4. Each suction gap 4 is closed by a shutter 5 when the extractor 1 is not in operation. The closing flaps 5 each have two side guides 15 which guide the closing flaps 5 during the opening and closing movements and - when the closing flaps 5 are in the open position - form the side walls of a suction channel. The closing flaps 5 are each moved by an opening mechanism 6.

If a hob with several cooking zones lying one behind the other is used, several exhaust air inlets with separate closing flaps can also be provided on the side. In this way, an exhaust air gap and a closing flap can be assigned to each cooking zone.

A control panel 11 is provided in front of the right closure flap 5. The extractor hood 1 can be switched on and off on this control panel 11. The various power levels can also be switched via this control panel 11.

Further components of the upper part 24 of the extractor hood 1 will be explained below with reference to FIG Figures 4 and 5 are explained in more detail.

The fan duct 7 connects the upper part 24 of the extractor hood 1 with the fan 8. The controller 23, which also contains the electrical connection 9, is attached to the fan 8. The controller 23 is electrically connected to the control panel 11 in a manner not visible here.

The extractor 1 shown here is designed as a circulating air extractor. It is therefore provided with the odor filter 10. The odor filter 10 is connected directly to the exhaust air outlet on the fan 8, which is invisible in this illustration. The cleaned exhaust air is fed back into the room via the base area of the base unit in which the extractor 1 is mounted.

In the sectional view in Fig. 2 the side guide 5 is omitted from the right-hand closure flap 5 for the sake of clarity. The cleaning module 14 can thus be seen, which can be pulled out completely upwards. The cleaning module 14 can be cleaned in a dishwasher, for example, and can then be reinserted into the extractor hood 1.

The cleaning module 14 has the guide plate 19 (the components of the cleaning module 14 are shown in detail in FIG Fig. 4 shown), the baffle plate 20, the filter 21 and the drip pan 22. The filter 21 is mounted over an opening so that the exhaust air leaves the cleaning module via the filter 21.

In Fig. 3 an alternative arrangement is shown. The extractor according to the invention is constructed here in such a way that three closure flaps 5 are provided for the exhaust air inlets on the rear edge of the hob 13. The control panel 17 is housed in the front part of the hob 13. Lateral exhaust air inlets were dispensed with in this exemplary embodiment. The hob 13 here has three individual cooking zones 16, all of which are directly adjacent to the respective exhaust air inlet under the closing flaps 5. This results in a better suction result, in particular for the central cooking zone 16, than in the case of an extractor hood with two side exhaust air inlets. The three adjacent exhaust air inlets are advantageously each equipped with their own cleaning module.

The two side exhaust air inlets of the first embodiment from the Figures 1 to 2 and 4 to 5 are, however, better suited for a hob with a square arrangement of four cooking zones.

In Fig. 5 the ratio of the flow cross-sections should be shown. The different flow cross-sections are necessary in order to be able to accelerate the exhaust air flow upstream of the first separation device, the baffle plate 20, accordingly. The guide plate 19 is provided for this purpose. The distance b between the lower edge of the baffle 19 and the free edge of the baffle 20 is about 60% of the distance a between the baffle 19 and the shutter 5 in the upper region of the exhaust air duct.

In the following, the function of the device according to the invention is intended in particular on the Figures 5 and 1 are explained in more detail. Cooking fumes rise from a source of exhaust air, not shown here, for example a saucepan or frying pan. The fan 8 builds up a strong cross flow above the hob, which catches the rising cooking vapors and pulls it in the direction of the suction gap 4.

The exhaust air flow is in Fig. 4 indicated by arrows. The cross-flowing cooking vapors are sucked into the suction gap 4 and forced in the direction of the baffle plate 20 through the exhaust air duct (e.g. closure flap 5 and guide plate 19). On the way to the baffle plate 20, the exhaust air flow is correspondingly accelerated by the narrowing of the flow cross section. The fan 8 is designed so that the exhaust air flow in the area of the baffle plate 20 reaches a speed between 8 and 10 m / s. These values apply to the highest power level of the fan 8.

The baffle plate 20 assumes an angle of approximately 20 ° with respect to the horizontal. The accelerated exhaust air flow is consequently very strongly deflected by the baffle plate 20. Due to the high speed and the strong deflection, even very small particles, in particular fat droplets, cannot take part in the strong deflection and, for reasons of inertia, describe a much less strongly curved trajectory than the exhaust air flow itself.

In doing so, they inevitably hit the baffle plate 20. The fat droplets collect on its surface and run due to the inclination of the baffle plate 20 in the direction of the free edge. From there the fat can drip off into the drip pan 22.

After passing through the opening between the baffle plate 20 and the lower edge of the baffle plate 19, the flow cross-section in the space in front of the filter 21 expands considerably. This also leads to a significant reduction in the speed of the exhaust air flow. The flow through the second separation device with the filter 21 thus takes place much more slowly than the flow through the first separation device.

When entering the filter 21, turbulence forms, which lead to the fact that any tiny fat droplets still contained in the exhaust air stream meet and accumulate to form larger fat droplets. These larger fat droplets come into contact with the filter material and can be deposited there again. Here, too, the separated fat can drain down into the collecting pan due to the vertical arrangement of the filter.

The longer the period of time that the exhaust air needs to flow through the filter 21, the higher the degree of separation. A large filter thickness would therefore be desirable. On the other hand, the flow resistance must not become too great, since otherwise a stronger fan would have to be used and the volume of the extractor would become too great. There are therefore limits to the thickness of the filter. In a thin filter with low flow resistance, fat separation is consequently greater if the speed of the exhaust air flow is as low as possible.

The first and the second separation device therefore complement each other perfectly. At a high power level of the fan 8, a very high degree of separation is achieved in the first separation device via the baffle plate 20. In the second separating device, which does not work so effectively at high exhaust air speeds, the filter 21 therefore only has to retain very small amounts of fat.

In contrast, when the fan 8 is at a lower power level, the first separating device works less effectively than when it is at a high power level. This means that larger particles are retained, but that very small particles are not separated, but rather carried along with the exhaust air. The degree of separation in the first separation device is therefore lower at a lower power level of the fan 8.

In the second separation device, however, the exhaust air flow will flow more slowly through the filter 21 at a low power level of the fan 8. Because of this lower flow rate, the degree of separation of the filter 21 increases, since the time span that the exhaust air needs through the filter is increased.

As a result, roughly the same overall degree of separation is achieved with a small and a large fan output level. With a high fan output and a high flow rate, the first separation device with the baffle plate 20 contributes the main part of the overall degree of separation. With a low fan power it is exactly the opposite. Here, the majority of the fat contained in the second separating device is removed by the filter 21.

After passing through the two filters 21, the two exhaust gas streams are brought together and diverted into the fan duct 7. At the exhaust air outlet, which is not visible here, in the in Fig. 1 An odor filter 10 is also connected.

In these odor filters, the exhaust air is usually led through carbon, which adsorbs the odor molecules with its large inner surface. The carbon has to be exchanged or regenerated from time to time.

The exhaust air that has been cleaned in the odor filter and freed from adhering odors can now be returned to the room. In this way, no heat is extracted from the room. The operation of the extractor according to the invention as a circulating air extractor is therefore ideally suited for the cold season in which the heated air should be kept in the room as far as possible.

But it is also possible to operate the extractor according to the invention as an exhaust air vent. For this purpose, a duct or hose is connected to the exhaust air outlet, which is not visible here, which leads to the outside and which with its open side z. B. ends on the outside wall of a house. Here the exhaust air, which is still laden with odors, is conveyed directly to the outside.

Of course, an embodiment is also possible in which both operating modes can be selected as alternatives. For example, a switch can be provided at the exhaust air outlet which either returns the exhaust air to the room via the odor filter 10 or directs the exhaust air directly to the outside.

The switch can either be controlled manually or, for example, via an external temperature sensor. In the second case, there is an automatic summer-winter operation that does not have to be actively initiated by the user of the extractor.

The extractor hood can be switched via the control panel 11. There is a function for switching on and off as well as a function for selecting the power level.

When the extractor is switched on, the closing flaps 5 are opened via the respective opening mechanism 6. The fan 8 is switched on a little later so that the suction force does not work against the opening force of the opening mechanism 6. The cross flow is now generated very quickly above the hob 13, with the aid of which the rising cooking vapors are captured and conveyed into the suction gap 4.

When switching off the extractor hood via the control panel 11, the fan 8 is switched off first. The closing flaps 5 are closed via the opening mechanism 6 with a short delay. This creates a smooth surface that can be flush with the worktop.

A sensor can also be provided in the drip pan 22. This sensor must be designed in such a way that it detects the level of the surface of the separated fat. If a certain level is reached, which requires cleaning, a corresponding message can be generated via the control. This can be, for example, an acoustic message or a visual alarm via the control panel 11. The alarm could be triggered, for example, when the range hood is switched on or off. In this way, the cooking process would not have to be interrupted by cleaning.

In order to save energy costs when operating the extractor according to the invention, only the closing flaps 5 that are required for sucking off the cooking vapors produced during cooking should always be open. In most cases only one cooking zone 16 is used, so that only one open flap 5 is sufficient.

The closing flaps 5 are therefore individually controllable. In this case, the fan 8 can be operated at a lower power level, since only an exhaust air flow has to be generated through an exhaust air inlet. Despite the lower energy consumption, the effect is the same as when all the closing flaps 5 are opened and the fan 8 has a correspondingly higher power level.

The required exhaust air inlets can be selected using the control panel 11. Alternatively, automatic detection is also possible. For example, the currently used cooking zones 16 can be determined by coupling the control 23 to the hob 13. However, sensors can also be provided in the frame 2 which determine the cooking zone on which a pot is placed. When the cooker hood 1 is switched on, only the shutter that is assigned to the cooking zone in use is opened.

List of reference symbols:

1

Extractor hood

2

frame

3

Mounting bracket

4th

Suction gap

5

Closing flap

6th

Opening mechanism

7th

Fan duct

8th

fan

9

Electrical connection

10

Odor filter

11

Control panel

12

Hob opening

13

Hob

14th

Cleaning module

15th

Side guide

16

Cooking zones

17th

Control panel

18th

hinge

19th

Baffle

20th

Baffle plate

21st

filter

22nd

Drip pan

23

control

24

Upper part of the extractor hood

Claims (4)

1. An apparatus (1) for extracting exhaust air from a hob, the apparatus (1) having an upper part (24), a fan duct (7) connecting the upper part (24) with a fan (8), and an exhaust air outlet, the upper part (24) comprising:

   a frame (2) including a hob opening (12) for receiving a hob having standard dimensions and, on both sides next to the hob opening (12), an exhaust air inlet (4) formed as an extraction slit, wherein each exhaust air inlet (4) has a movable closure flap (5) and each closure flap (5) has two side guides (15) guiding the closure flap (5) during opening and closing and, in an open position of the closure flap (5), define side walls of an intake duct;

   a cleaning module (14) associated with and communicating with the exhaust air inlet (4), which cleaning module (14) provides an exhaust air duct and which exhaust air duct in the flow direction of the exhaust air comprises a guide plate (19), a baffle plate (20) providing a first separating means, a filter (21) providing a second separating means, and a drip tray (22) for collecting the separated grease droplets, wherein

   the exhaust air duct has a flow cross-section which decreases towards the baffle plate (20) and increases towards the filter (21) by arranging the guide plate (19) such that a distance (b) between a lower edge of the guide plate (19) and a free edge of the baffle plate (20) is approximately 60% of a distance (a) between the guide plate (19) and the closure flap (5) in an upper region of the exhaust air duct,

   so that the baffle plate (20) arranged for deflecting the exhaust air at an angle of approximately 20° with respect to the horizontal, is supplied with an accelerated exhaust air flow due to the reduction of the flow cross-section, and

   the vertically arranged filter (21) is supplied with a slowed down exhaust air flow due to the increase of the flow cross-section.
2. The apparatus according to claim 1, characterized in that the at least one filter (21) is made of metal.
3. The apparatus according to claim 1 or 2, characterized in that a drip tray (22) is provided below the deflecting element (20) and the at least one filter (21).
4. The apparatus according to one of claims 1 to 3, characterised in that the exhaust air outlet returns the exhaust air into the room via an odour filter (10) or conducts it outside via a further exhaust air duct.

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