EP4027063A1 - Vapour extraction device, kitchen appliance comprising a cooker hob and vapour extractor device and method for operating a vapour extraction device - Google Patents

Abstract

The present invention relates to a fume extraction device with a suction opening (20) and a blower arranged under the suction opening (20), via which the primary air (P) is sucked downwards via the suction opening (20), the fume extraction device being characterized in that the fume extraction device (2) has at least one blow-out opening (21) which is adjacent to the suction opening (20) and through which a directed secondary air flow (S) is blown out. The invention also relates to a kitchen appliance (1) with at least one such vapor extraction device (2) and a method for operating such a vapor extraction device (2).

Description

The present invention relates to an extractor device, a kitchen appliance with a hob and an extractor device, and a method for operating an extractor device.

To clean fumes and vapors that arise when cooking on a hob, it is known to use extractor hoods that are attached above the hob, for example on a room wall. These extractor hoods suck the fumes and vapors upwards. In addition, so-called downdraft ventilation or table ventilation are also known, which can also be referred to as hob ventilation, in which vapors and vapors are sucked off downwards. An embodiment of a downdraft ventilation is for example in DE 10 2010 042 436 A1 described. With this downdraft ventilation, a suction body that can be extended vertically from a hob and has a vertical suction opening is used.

With hob ventilation, the rising vapor is drawn in downwards or from the side against the physical buoyancy. This requires high air velocities or suction capacities, which result in a high level of noise. If there are large distances between the cooking vessel and the suction opening, vapor trapping is not possible or the vapor trapping rate is low. In addition, most hob ventilation systems have difficulty capturing the rising vapors from higher cooking vessels, such as pots. If there are cross currents in the room, a significantly reduced vapor collection can also be noticed.

The invention is therefore based on the object of creating a solution with which the vapor extraction behavior of a cooktop ventilation system can be improved with a lower delivery volume required.

The invention is based on the finding that this can be done by targeted air guidance of a secondary air flow, which influences the sucked vapors at least in the vicinity of the suction opening.

According to a first aspect, the object is therefore achieved by a fume extraction device with a suction opening and a blower which is arranged under the suction opening and via which the primary air is suctioned downwards via the suction opening. The fume extraction device is characterized in that the fume extraction device has at least one exhaust opening which is adjacent to the suction opening and via which a directed secondary air flow is blown out.

An extractor device is a device by means of which air, in particular contaminated air in the form of fumes and vapors, can be extracted from a hob and/or a worktop. The vapor extraction device preferably has at least one filter element for cleaning the air. In particular, at least one grease filter and optionally an odor filter can be provided in the vapor extraction device. The extractor device has a suction opening. According to the invention, several extraction openings can also be provided on the fume extraction device. In the following, however, the invention is essentially described with reference to an extractor device with only one suction opening. A fan is arranged below the suction opening. Several fans can also be provided in the fume extraction device. In the following, however, the invention is essentially described with reference to an extractor device with a fan. The fan can also be referred to as a fan or suction fan. Air is extracted downwards via the extraction opening by the blower. The air that is extracted is referred to as primary air and is in particular contaminated air in the form of fumes and vapors.

The fume extraction device is characterized in that it has at least one exhaust opening which is adjacent to the suction opening and through which a directed secondary air flow is blown out. The at least one exhaust opening can be in the form of a hole or a slit. However, it is also in It is part of the invention that the at least one blow-out opening is formed by a pipe end or an opening in the outer wall of a pipe. In this case, the blow-out opening can also be referred to as a nozzle. The air can be guided from the blower to the at least one exhaust opening by means of a duct, which can have a round or rectangular cross section (flat duct). The blow-out opening is arranged adjacent to the suction opening. A blow-out opening is referred to as being adjacent to the suction opening, which is at a small distance from the suction opening in the horizontal direction and preferably adjoins the suction opening and is only optionally separated from the suction opening by a separating element. In the vertical direction, the at least one exhaust opening can be in the plane of the exhaust opening or, in particular in the case of a so-called downdraft extractor device with an exhaust body with an exhaust opening in the vertical to the exhaust opening, can be offset downwards. The suction opening is preferably located in the horizontal direction between the space from which air is to be sucked, in particular the space above a cooktop, and the at least one exhaust opening.

A directed secondary air flow is blown out via at least one outlet opening. The secondary air flow is also referred to below as the supply air flow, secondary air flow or secondary fluid flow, secondary fluid. The secondary air can be fresh air from the room in which the vapor extraction device is operated, fresh air from outside the room or vapors and vapors extracted from the room and preferably cleaned. A directed air flow is an air flow which, due to the geometry of the blow-out opening and/or the speed at which the air flow is blown out, flows at least over a certain distance in a predetermined direction.

By providing, according to the invention, at least one blow-out opening adjacent to the suction opening and through which a directed secondary air flow can be blown out, the direction and speed of the primary air flow, which is determined by the blower and the thermals on a hob, can be specifically changed or supported in at least individual areas will. In particular, the primary air flow can be directed to the suction opening. As a result, the volume flow sucked in via the suction opening can be increased and/or the demand on the blower for sucking off the primary air can be reduced. Thus, with the present invention the vapor trapping rate and thus the efficiency of the vapor extraction device can be increased. In addition, the fan can be operated at a lower power or a smaller fan, ie a fan with a lower nominal power, can be used. This reduces the noise generated when sucking off the primary air and reduces the energy requirement.

If several exhaust openings are provided on the vapor extraction device, they can be arranged in a common orientation. However, it is also within the scope of the invention for a first group of exhaust openings to be aligned in a first direction and a second group in a second direction. In addition, it is also possible for each exhaust opening to be aligned in a different direction.

According to one embodiment, at least one blow-out opening is horizontal. With this arrangement of the at least one exhaust opening, the secondary air can be discharged upwards in a vertical direction.

Unless otherwise stated, directional information such as up, down, front and back refer to an extractor device in the installed state behind a hob. The indication of direction at the front of the extractor device refers to the side of the extractor device that faces the hob. For easier reference, in figure 3 a coordinate system is given, which is referred to below. Here, the x-axis is horizontal and extends in the depth direction of the vapor extraction device and a hob arranged in front of the vapor extraction device. The y-axis is also horizontal, extends perpendicularly to the x-axis and runs in the width direction of the extractor hood and the hob. The z-axis is vertical and thus runs in the height direction of the vapor extraction device and is perpendicular to the x- and y-axes.

Since at least one exhaust opening is horizontal, the secondary air can be discharged via the exhaust opening in a direction that has at least a vertical directional component and is directed vertically upwards, for example. In addition, the horizontal position of the at least one exhaust opening can simplify the structure of the vapor extraction device. In particular, the exhaust opening or the exhaust openings can be at a height that corresponds to the height of the hob. As a result, it is not necessary to provide a separate exhaust duct extending across the height of the top side of the cooktop.

According to a further embodiment, at least one blow-out opening is vertical. As a result of this orientation, a secondary air flow which has at least a horizontal directional component can be emitted via the at least one blow-out opening. For example, the secondary air flow can be output horizontally. In particular, a secondary air flow directed to one of the sides of the extractor hood and thus to one of the sides of the hob can be generated via the blow-out opening lying in the vertical.

According to a further embodiment, at least one exhaust opening is inclined to the vertical and horizontal. In this arrangement, with a simple configuration, the blow-out opening can be designed, for example, as a hole or a slit, via which secondary air is discharged in a direction transverse to the horizontal and vertical. In this embodiment, the exhaust openings can be arranged, for example, on the upper side of a semicircular duct and a fan-shaped secondary air flow can thus be emitted upwards via these exhaust openings. Instead of a simple hole or slit, a nozzle can also form the blow-out opening.

As already mentioned above, when a plurality of exhaust openings are provided, the orientations of the individual exhaust openings can be the same or different in relation to one another.

According to a further embodiment, at least one blow-out opening is directed upwards. A blow-out opening is referred to as being directed upwards, via which secondary air can be discharged in a direction with a directional component directed vertically upwards. The direction of the exhaust opening can be determined by its arrangement on the fume extraction device and, if necessary, additionally by its geometry. For example, a blow-out opening lying in the horizontal can be formed by a bore or a hole that runs inclined to the vertical. A secondary air stream can thus be discharged through this horizontal exhaust opening, which flows transversely upwards. Since the exhaust direction is directed upwards, the secondary air can form an air curtain that delimits the area above the hob. In addition, the primary air above the level of the Hob can be specifically influenced. In particular, at least part of the primary air can be entrained counter to the main suction direction of the suction opening. The effect achieved in this way is explained in more detail below.

According to a further embodiment, the exhaust opening is above the level of the suction opening and is inclined downwards. In one embodiment, in which the extractor device is a downdraft extractor device with a vertical suction opening, the exhaust opening can be above the level in which the suction body protrudes upwards from the housing of the extractor device, in particular above the level of the hob and be inclined downwards. A blow-off opening, through which secondary air can be discharged in a direction which has at least a downward directional component, is referred to as being inclined downward. The blow-out opening is preferably aligned in such a way that the secondary air always has a horizontal directional component, that is to say it is not discharged vertically downwards. The secondary air can at least partially influence the primary air in the direction of the suction opening by means of a downwardly inclined exhaust opening.

The at least one blow-out opening can be provided on a blow-out channel. The exhaust duct can be provided in the fume extraction device in such a way that its upper side lies in the plane of the extraction opening. In particular, the upper side of the exhaust duct can lie in the plane of the hob and a worktop in which the hob is installed. This level preferably corresponds to the level of the suction opening. In one embodiment, in which the vapor extraction device is a downdraft vapor extraction device, the level of the suction opening lies above the level of the hob and any worktop that may be provided. In this embodiment, the exhaust duct is arranged in one embodiment in such a way that the upper side of the exhaust duct lies in the plane of the cooktop and possibly the worktop.

According to one embodiment, the at least one blow-out opening is provided on a blow-out channel that extends upwards from the plane in which the suction opening is located. The level in which the suction opening is located is preferably the level of the hob. However, in an embodiment in which the fume extraction device is a downdraft fume extraction device, the level of the suction opening is located above the level of the hob and any worktop provided. In this embodiment, the exhaust duct extends upwards from the level of the hob and, if applicable, the worktop. Since the exhaust duct extends above the level of the hob and preferably the level of the suction opening, the targeted influencing of the primary air that is produced above the hob can be guaranteed in a simple manner, since the exhaust openings are arranged at a certain height above the hob be able.

The suction opening preferably has a width that corresponds to the width of the hob from which the primary air is to be suctioned. The width, i.e. the extent of the suction opening in the Y direction, is preferably greater than its depth, i.e. its extent in the X direction of the figure 3 defined coordinate system.

According to one embodiment, the exhaust duct, which extends upwards from the plane of the hob, is arranged in the middle of the width of the suction opening. Alternatively, two blow-out channels are provided, which are arranged at the lateral ends of the width of the suction opening. In both cases, the exhaust channel is adjacent to the suction opening and is preferably offset to the rear. In the case of the arrangement of the exhaust duct in the middle of the width of the suction opening, exhaust openings are preferably provided on both sides of the exhaust duct which lie in the width direction, ie the Y-direction. In the embodiment in which two blow-out channels are provided and one each is arranged at a lateral end of the width of the suction opening, blow-out openings are introduced only in one side of the respective blow-out channel.

According to a preferred embodiment, the fume extraction device has a separating element which is arranged between the suction opening and the at least one exhaust opening. The separating element is preferably a flat element that extends over the entire width of the suction opening. By providing a separating element, in particular when the at least one exhaust opening is arranged in the plane of the suction opening, secondary air can be prevented from being sucked directly into the suction opening, even if the speed of the secondary air is low. However, it is also possible with sufficient speed and possibly suitable orientation of the secondary air flow that between the suction opening and the at least there is no separating element in a blow-out opening. Mixing of the secondary air and the primary air below the level of the suction opening can be prevented by the rear wall of a suction channel, the top of which forms the suction opening, and/or the front wall of a blow-out channel.

The separating element preferably extends vertically upwards from the plane of the suction opening. As a result, the secondary air jet discharged from a blow-out opening behind the separating element is guided in a targeted manner at least over the path over which the secondary air stream flows along the separating element. In addition, the direct suction of secondary air into the suction opening is reliably prevented by a separating element that extends vertically upwards.

According to one embodiment, the separating element is a baffle plate. The baffle plate can be movably fastened to the fume extraction device, in particular the baffle plate can be moved into and out of the housing of the fume extraction device. In this way, different heights of cooking vessels can be taken into account or the baffle plate can be retracted when the vapor extraction device is not in use. Alternatively, the baffle plate can also be fixed to the extractor device. The baffle plate can be a disk, for example made of glass, plastic or metal. By using a baffle as a separator, the distance between the flow in front of the baffle and the flow behind the baffle is small. As a result, the two flows can influence one another at the edges of the baffle plate. In particular, when using a thin separating element, in particular a baffle plate, no undesired turbulence occurs at the edges of the baffle plate.

The baffle plate preferably has a thickness in the range from 2 mm to 20 mm. The thickness of the baffle plate is particularly preferably in the range from 5 to 10 mm, in particular 6 mm. It has been shown that with a baffle plate of this thickness, a targeted formation of vortices on the upper edge of the baffle plate can be achieved or this is at least promoted. The primary air flow is also directed to the suction opening by the vortices.

According to an alternative embodiment, the separating element is a suction body which has at least one suction opening on the side facing away from the at least one blow-out opening. The suction body can also be referred to as a suction channel. In the embodiment in which the separating element represents a suction body, the vapor extraction device represents a so-called downdraft vapor extraction device. The suction body can be attached to the housing of the vapor extraction device in a fixed or movable manner. The suction body preferably has a small depth.

The secondary air flow, which is emitted via the at least one exhaust opening, can be generated by the fan of the vapor extraction device. In particular, part of the primary air sucked in via the suction opening and possibly cleaned in the vapor extraction device can be branched off via a bypass and fed to the exhaust openings. In this case, a variable secondary air flow, ie one dependent on the primary air flow, is formed. In this embodiment, the speed of the secondary air flow can optionally also be determined by the geometry of the outlet openings.

According to one embodiment, part of the exhaust air flow can thus be used to advantageously influence the vapor. Here, a part of the air, which may have been cleaned of grease and odors, can be removed from the exhaust air flow via a bypass. For the purposes of the present invention, the air flow that was sucked off and cleaned by the vapor extraction device is referred to as the exhaust air flow. Alternatively, this air can be fed back into the room in which the vapor extraction device is operated or released into the environment. The fume extraction device can therefore be designed as an exhaust air or circulating air fume extraction device.

According to one embodiment, the fume extraction device has an additional fan which is connected to the at least one exhaust opening. In this embodiment, fresh air can be sucked in from the room in which the vapor extraction device is operated or from the environment and blown out of the exhaust openings as a secondary air flow. In this embodiment, a constant secondary air flow can thus be generated. The additional fan can, for example, suck in a flow of fresh air from the furniture base cabinet in order to influence the vapors in an advantageous manner.

Clean air is sucked in from the kitchen base cabinet. Alternatively, clean air can be sucked in from outside.

According to a further aspect, the invention relates to a kitchen appliance with a hob and at least one extractor device, which represents an extractor device according to the invention.

Advantages and features that are described with regard to the extractor device apply--insofar as applicable--to the kitchen appliance according to the invention and vice versa and are therefore only described once, if necessary.

The kitchen appliance has a hob and at least one vapor extraction device. The hob and the extractor device can be built into a worktop. In this case, the hob and extractor device(s) can be installed in a common recess in the worktop. However, it is also within the scope of the invention that at least the vapor extraction device and the hob are placed in separate recesses in the worktop. The at least one vapor extraction device is preferably provided on an edge of the hob in such a way that the extraction opening of the vapor extraction device extends along the edge of the hob.

In addition, the suction opening is arranged in the horizontal direction between the at least one exhaust opening and the hob. This means that the suction opening is closer to the hob than the at least one exhaust opening. In addition, the primary air flow, which is sucked in via the suction opening, is influenced in the vicinity of the suction opening. The invention thus differs from fume extraction devices in which a supply air flow is generated on the side of the hob opposite the suction opening and is directed towards the suction opening.

According to a preferred embodiment, the at least one vapor extraction device is arranged behind the hob. An extractor device is referred to as being arranged behind the hob, in which the suction opening and the at least one exhaust opening are in the negative X-direction in the coordinate system figure 3 lie. In this position, for example, with a hob that is installed on a cooking island an air curtain can be formed behind the hob and thus influencing the flow conditions over the hob from behind can be avoided.

According to one embodiment, the fume extraction device has a baffle plate, which is provided as a separating element between the suction opening and the at least one exhaust opening. The width of the baffle plate corresponds, for example, to the width of the hob. In this way, targeted shielding of the suction opening, which preferably also corresponds to the width of the cooktop, can be guaranteed.

According to a further aspect, the invention relates to a method for operating a vapor extraction device according to the invention. The method is characterized in that at least one secondary air flow is discharged via the at least one exhaust opening in such a way that the at least one secondary air flow is directed outwards over the sides of the suction opening.

The secondary air flow directed outwards over the sides can also be referred to as an air curtain or air film and is preferably fed by more than one exhaust opening. The air curtain can represent a continuous curtain or be formed from individual secondary air flows. The speed of the air can vary slightly across the air curtain in the latter case. The secondary air flow is directed outwards at least over the sides of the suction opening. The longitudinal ends of the preferably elongate suction opening are referred to as the sides of the suction opening. Thus, the secondary air flow is directed in the direction of the width of the suction opening and thus also in the direction of the width of the vapor extraction device and the hob. As a result of this orientation of the secondary air flow, it is transverse to the main direction of the primary air flow, which is drawn in from the hob in the direction of the suction opening by the suction of the fan. On the one hand, this can prevent vapors from escaping to the rear, since the secondary air flow can serve as an air curtain and can shield the area above the hob to the rear. On the other hand, at least part of the primary air flow can be entrained by the secondary air flow due to the direction of the secondary air flow, which is transverse to the flow direction of the primary air flow in the negative x-direction. For reasons of continuity, further primary air flows in the direction of the suction opening due to the entrained part of the primary air flow and can be sucked into the suction opening by the fan of the vapor extraction device will. The secondary air flow can also be directed upwards or downwards, at least in some areas, in addition to being directed outwards.

If a baffle plate is provided, the air curtain is preferably formed parallel to the baffle plate and forms a kind of extension of the baffle plate on both sides and obliquely upwards. It delimits the lateral area in front of and behind the impact plate. This also prevents a lot of primary air from being extracted from the sides.

Advantages and features that are and have been described with regard to the method according to the invention also apply - insofar as applicable - to the extractor device according to the invention and the kitchen appliance according to the invention and vice versa and are therefore only described once if necessary.

According to one embodiment, the secondary air flow is aligned in such a way that it lies in a plane that is parallel to a plane in which the longitudinal extent of the suction opening lies. However, according to the invention it is also possible for the secondary air flow to be directed in a direction which is inclined forwards, in particular towards the hob. However, this inclination of the secondary air flow is preferably small and in particular less than 90°, preferably less than 45°. According to one embodiment, the secondary air flow can be discharged in such a way that it is directed at least in some areas from behind onto a separating element, flows along the separating element and tears away from the lateral edge of the separating element and flows outwards laterally.

According to a preferred embodiment, the secondary air is discharged in a fan shape. In this way, a secondary air flow discharged from a blow-out opening can be fanned out. Alternatively, secondary air streams from several exhaust openings can form a fan shape together.

According to one embodiment, the secondary air flows upwards at least in the edge area of the upper edge of the separating element and the secondary air flow forms at least one vortex in the middle area of the upper edge of the separating element. The center of the at least one vortex is in front of the separating element. Because the center of the vortex is in front of the separating element, it can allow primary air to escape upwards and also directs rising primary air downwards in the direction of the suction opening at an early stage, thus supporting the suction. Preferably, two symmetrical whorls are formed. In particular in the case of an air flow which is divided into two compartments, a vortex preferably forms on the sides of the respective compartment part which face one another, ie between which no secondary air flows upwards. The vortices are thus in the middle area of the width of the upper edge of the flapper. The two vortices can be separated from one another in the width direction of the baffle plate or form a common vortex. The axis of the vertebrae or vertebrae is parallel to the flapper.

The speed of the secondary air flow is preferably greater than the speed of the primary air flow at the suction opening. As a result, a direct suction of the secondary air into the suction opening can be prevented even without a separating element.

According to one embodiment, the average outlet speed of the secondary air at the outlet opening is in the range of 6 to 7 m/s at a secondary air volume flow of 120 to 150 m ³ /h. For example, an exit speed of the secondary air in the range from 6 to 7 m/s can be set at a volume flow in the range from 130 to 150 m ³ /h. The exit velocity designates the vertical velocity component. The outlet speed can be higher by changing the geometry of the outlet opening, in particular of nozzles with a smaller outlet opening, or lower in the case of nozzles with a larger outlet opening. The exit speed indicates an average exit speed, it being possible for the exit speed to be unevenly distributed over the outlet opening or nozzles provided therein. If low exit velocities are used, a high volume flow is preferably set in order to be able to continue to achieve the advantages of the invention.

With the present invention, a targeted air flow can be achieved in a simple manner, for example by adjusting the parameters of the thickness of the baffle plate, the suction power of the fan, the size and position of the suction opening, the height of the baffle plate and the volume flow, speed and direction of the secondary air flow and influencing the primary air. In particular, at the top of the baffle plate form at least one vortex of the secondary air, through which the primary air can be prevented from escaping and sweeping past the upper edge of the baffle plate and which also supports the intake of the primary air.

• Figur 1: eine schematische Rückansicht (1a), Seitenansicht (1b) und Draufsicht (1c) einer ersten Ausführungsform des erfindungsgemäßen Küchengerätes;
• Figur 2: eine schematische Rückansicht (2a), Seitenansicht (2b) und Draufsicht (2c) einer zweiten Ausführungsform des erfindungsgemäßen Küchengerätes;
• Figur 3: eine schematische Perspektivansicht einer Ausführungsform eines erfindungsgemäßen Küchengerätes mit Koordinatensystem;
• Figur 3a: eine schematische Perspektivansicht mit Darstellung der Strömungsgeschwindigkeiten;
• Figuren 4a und 4b: Darstellungen der Strömungsverhältnisse durch die seitlichen Ebenen Y+, Y- ohne und mit Sekundärluftstrom als Stromlinien;
• Figuren 4c und 4d: Darstellungen der Strömungsverhältnisse durch die seitlichen Ebenen Y+, Y- ohne und mit Sekundärluftstrom als Geschwindigkeitsvektoren entlang Stromlinien;
• Figuren 5a und 5b: Darstellungen der Strömungsverhältnisse durch die seitlichen Ebenen Y+, Y- ohne und mit Sekundärluftstrom als Geschwindigkeitsvektoren entlang Stromlinien in Perspektivansicht;
• Figuren 6a und 6b: Darstellungen der Strömungsverhältnisse durch die hintere Ebene X- ohne und mit Sekundärluftstrom als Geschwindigkeitsvektoren entlang Stromlinien in Perspektivansicht;
• Figuren 7a und 7b: Darstellungen der Strömungsverhältnisse durch die obere Ebene Z+ ohne und mit Sekundärluftstrom als Geschwindigkeitsvektoren entlang Stromlinien in Perspektivansicht;
• Figuren 8a und 8b: Darstellungen der Strömungsverhältnisse durch die vordere Ebene X+ ohne und mit Sekundärluftstrom als Geschwindigkeitsvektoren entlang Stromlinien in Perspektivansicht;
• Figur 9: schematische Darstellungen unterschiedlicher Ausführungsformen eines Trennelementes in Frontansicht;
• Figur 10: eine schematische Rückansicht (10a), Seitenansicht (10b) und Draufsicht (10c) einer dritten Ausführungsform des erfindungsgemäßen Küchengerätes;
• Figur 11: eine schematische Rückansicht (11a), Seitenansicht (11b) und Draufsicht (11c) einer vierten Ausführungsform des erfindungsgemäßen Küchengerätes;
• Figur 12: eine schematische Rückansicht (12a), Seitenansicht (12b) und Draufsicht (12c) einer fünften Ausführungsform des erfindungsgemäßen Küchengerätes;
• Figur 13a: eine schematische Perspektivansicht mit Darstellung der Strömungsgeschwindigkeiten; und
• Figur 13b: eine schematische Seitenansicht der Ausführungsform nach Figur 13 mit einer tangentialen Projektion der Geschwindigkeitsvektoren.

The present invention is described again below with reference to the accompanying figures. It shows:

• figure 1 1: a schematic rear view (1a), side view (1b) and top view (1c) of a first embodiment of the kitchen appliance according to the invention;
• figure 2 : a schematic rear view (2a), side view (2b) and top view (2c) of a second embodiment of the kitchen appliance according to the invention;
• figure 3 : a schematic perspective view of an embodiment of a kitchen appliance according to the invention with a coordinate system;
• Figure 3a : a schematic perspective view showing the flow velocities;
• Figures 4a and 4b : Representations of the flow conditions through the lateral planes Y+, Y- without and with secondary air flow as streamlines;
• Figures 4c and 4d : Representations of the flow conditions through the lateral planes Y+, Y- with and without secondary air flow as velocity vectors along streamlines;
• Figures 5a and 5b : Representations of the flow conditions through the lateral planes Y+, Y- without and with secondary air flow as velocity vectors along streamlines in a perspective view;
• Figures 6a and 6b : Representations of the flow conditions through the rear plane X- without and with secondary air flow as velocity vectors along streamlines in a perspective view;
• Figures 7a and 7b : Representations of the flow conditions through the upper plane Z+ without and with secondary air flow as velocity vectors along streamlines in a perspective view;
• Figures 8a and 8b : Representations of the flow conditions through the front plane X+ without and with secondary air flow as velocity vectors along streamlines in a perspective view;
• figure 9 1: schematic representations of different embodiments of a separating element in front view;
• figure 10 : a schematic rear view (10a), side view (10b) and top view (10c) of a third embodiment of the kitchen appliance according to the invention;
• figure 11 1: a schematic rear view (11a), side view (11b) and top view (11c) of a fourth embodiment of the kitchen appliance according to the invention;
• figure 12 : a schematic rear view (12a), side view (12b) and top view (12c) of a fifth embodiment of the kitchen appliance according to the invention;
• Figure 13a : a schematic perspective view showing the flow velocities; and
• Figure 13b : a schematic side view of the embodiment according to FIG figure 13 with a tangential projection of the velocity vectors.

In figure 1 a first embodiment of the kitchen appliance 1 according to the invention is shown. The kitchen appliance 1 includes a hob 3 and a vapor extraction device 2. The vapor extraction device 2 includes a suction opening 20 and a plurality of exhaust openings 21. The exhaust openings 21 are formed in the upper side of an exhaust channel 210. A separating element 22 in the form of a baffle plate 220 is arranged between the blow-out openings 21 and the suction opening 20 . The fume extraction device 2 also has a fan (not shown), via which air is sucked into the suction opening 20 becomes. In addition, the fume extraction device 2 can have an additional fan (not shown), via which air is routed to the at least one exhaust opening 21 .

The extractor device 2 also has a housing 23, from which figure 1 only a cover can be seen. The hob 3 is arranged in front of the suction opening 20 . A cooking vessel G in the form of a pot is shown schematically on the hob 3 .

How out figure 1 results, in the first embodiment of the cooking appliance 1 the secondary fluid flow S is output in a fan shape. As shown, the secondary air flow S can be blown out from the blow-out openings 21 in the direction of the baffle plate 220 . The type of generation of the secondary volume flow for the secondary air flow S and the presence or the geometry of the baffle plate 220 are irrelevant for the effect according to the invention.

Secondary air is blown out of the blow-out openings 21 from the blow-out channel 210 . It is also within the scope of the invention that the exhaust duct 210 has only one exhaust opening 21 which extends over the entire length of the upper side of the exhaust duct 210 . The blow-out takes place as in figure 1 shown near the baffle plate 220. The secondary air can first be discharged through the exhaust opening 21 in the direction of the baffle plate. Because of the proximity to the baffle plate 220 , the fan-shaped secondary volume flow S is applied to the baffle plate 220 . This effect is also known as the Coanda effect. At the outer edges of the baffle plate 220, the secondary fluid experiences a slight deflection in the direction of the hob, and the secondary fluid flow S thus breaks off. A boundary layer flow occurs between the secondary fluid flow S outside the baffle plate 220 . The boundary layer flow is present here even without the presence of a solid boundary. The primary fluid is entrained by air friction and directed in the desired direction towards the suction opening. Due to the mass movement of the primary fluid in the direction of the tear-off edge, the primary fluid is divided in the direction of suction and in the opposite direction to suction (following the secondary fluid). A continuous flow develops. As a result, the primary fluid is increasingly directed from the front and upper area of the hob in the direction of extraction.

In addition, the secondary fluid flow S forms an air curtain which makes it considerably more difficult for air to flow from the area in front of the impact plate 220 to the area behind the impact plate 220 .

The effects on vapor capture rate by the deflection of the primary fluid flow P due to the entrainment effect of the secondary fluid flow will be discussed later with reference to FIG Figures 4 to 8 described in more detail.

In the figure 2 a second embodiment of the cooking appliance according to the invention is shown. The second embodiment differs from the first embodiment only in that, in the second embodiment, a suction body 221 is provided as a separating element 22 instead of a baffle plate 220 . The suction body 221 represents a hollow body closed at the top, which can also be referred to as a channel. The suction opening 20 of the fume extraction device 2 is formed in the upper area of the side of the suction body 221 . Air can be sucked in via the hollow suction body 221 to the blower (not shown) located below the level of the hob 3 . In this embodiment, too, a fan is formed by the secondary fluid flow S, which is blown out through the blow-out openings 21 , which fan extends at least beyond the lateral edges of the suction body 221 . Thus, also in the second embodiment according to figure 2 an entrainment effect of the primary air flow P is generated by the secondary air flow S and the primary air flow P is reliably directed to the suction opening 20 in the suction body 221 .

In figure 3 the geometry of an embodiment of the cooking appliance is shown with reference planes. In Figure 3a the outlet form of the mass flow of the secondary fluid is shown. As can be seen from this illustration, the secondary airflow S forms a fan that extends along the rear of the baffle 220 to the sides of the baffle 220 and protrudes beyond. The mass flow is low in the vertical direction. However, it is also within the scope of the invention for the secondary fluid stream S to also be directed upwards and extend beyond the top of the baffle plate. The velocity of the secondary fluid flow is higher near the exhaust port and decreases further away from the exhaust port. In particular, once the edges of the impact plate 220 are reached, the speed decreases.

In the Figures 4 to 8 are the flow conditions through different reference levels of the figure 3 shown in different representations. The flow conditions with and without secondary air flow are shown here.

A negative effect on the vapor trapping rate has an excessive volume flow flowing from the sides of the suction opening (Y+ and Y- planes) to the suction. Such a volume flow can arise, for example, by sucking in air around the hob. The lateral primary volume flow, on the other hand, only has a minor influence on the vapor trapping rate and takes up a large part of the total required extraction capacity of the fan.

In the Figures 4a and 4b representations of the flow conditions through the lateral planes Y+, Y- without and with secondary air flow are shown as streamlines. How out Figure 4a and 4b results, the secondary airflow entrains mass of the primary airflow in its front area as soon as the secondary airflow passes the edge of the impact plate. For reasons of continuity, mass of the primary fluid must flow. This results in the lateral outer area being separated from the inner area by an air curtain through the primary fluid. The outer rear area, ie the lateral area behind the baffle plate, is also separated from the lateral front area by the secondary air flow. The primary fluid is deflected downwards towards the suction opening 20 and only part of the mass of the primary fluid is entrained by the secondary fluid.

Figures 4c and 4d show the flow conditions through the lateral planes Y+, Y-without and with secondary air flow as velocity vectors along streamlines and Figures 5a and 5b show representations of the flow conditions through the lateral planes Y+, Y- with and without secondary air flow as velocity vectors along streamlines in a perspective view. As can be seen from these figures, a more targeted suction of the primary fluid is achieved.

Figures 6a and 6b show representations of the flow conditions through the rear plane X- without and with secondary air flow as velocity vectors along streamlines in a perspective view. How out Figure 6a results, a large part of the sucked-in primary volume flow comes from the area behind the hob and in particular behind the baffle plate. This volume flow is undesirable because it occurs when the suction power is too weak the fumes that are produced on the hob cannot be dragged down with it and takes up part of the entire extraction capacity. In the Figure 6a on the other hand, the flow conditions are shown through the rear plane X-. It can be seen here that the leakage current from the area behind the hob and in particular behind the baffle plate is limited. The leakage flow is limited in particular by the fact that the secondary fluid entrains mass of the primary fluid for reasons of continuity. This already happens at the break point at the edge of the impact plate. As a result, a flow tendency in the direction of the suction opening and the baffle plate is imposed on the primary fluid even in the distant upper area. In addition, the secondary fluid acts as an air curtain that prevents primary fluid from being drawn in from behind the flapper.

In the Figures 7a and 7b representations of the flow conditions through the upper plane Z+ without and with secondary air flow are shown as velocity vectors along streamlines in a perspective view. In particular, this shows the flow conditions in the vicinity of the cooking vessel G. The primary volume flow is deflected downwards in the direction of the suction opening and baffle plate by the effect of the secondary air jet.

From the Figures 8a and 8b , which show representations of the flow conditions through the front plane X+ without and with the secondary air flow as velocity vectors along stream lines in a perspective view, shows that the effect of the secondary air flow also has an effect in the front area of the hob. The primary volume flow changed by the secondary volume flow counteracts the naturally rising thermals of the vapor and pulls it in the direction of the baffle plate to the extraction opening.

In the Figure 13a the outlet shape of the mass flow of the secondary fluid is shown in one embodiment of the fume extraction device. As can be seen from this illustration, the secondary airflow S forms a fan that extends along the rear of the baffle 220 to the sides of the baffle 220 and protrudes beyond. The mass flow is lower in the vertical direction. In particular, the fan of the secondary air flow splits.

Due to the separation of the secondary air flow S at the upper edge of the baffle plate 220 and the suction of the primary air flow (in Figure 13a not shown) in front of the impact plate 220, two vortices W are formed. The vortices W are created by the secondary air flow rolling up as soon as it passes the upper edge of the baffle plate 220 . In the ideal case, the vortices W are stationary. The vortices W create an additional component that deflects the rising vapors, ie the primary air flow, downwards in the direction of the suction opening at an early stage. this is in Figure 13b is shown schematically showing a tangential projection of the velocity vector onto a plane normal to the Y-axis at a distance of 100 mm from the vertical outer edge of the flapper 220. In this representation, the vortex formation at the upper edge of the baffle plate 200, in particular the rolling up of the secondary air flow at the upper edge of the baffle plate 220 and the effect on the primary air flow in the lower area of the baffle plate 220 can be seen. In addition, it is avoided that the fumes in the outer area of the baffle plate 220 are entrained by the secondary air flow.

The exact shape of the baffle is not important. However, a minimum height can be advantageous in order to separate the primary volume flow from the secondary volume flow from one another, so that no primary fluid containing vapors is entrained in the lower area. The height and width of the baffle plate are not decisive for the functional principle. However, different optimal dimensions can be selected for different applications, for example the height of the baffle plate depending on the pot height or the width depending on the hob width. As already explained, the shape of the separating element and in particular of the baffle plate has no influence on the effect of the secondary air flow. Different types and shapes of baffle plates can thus be used. In figure 9 various forms of baffle plates are shown schematically. How out figure 9 results, indentations ( Figures 9b, 9c and 9d ) be provided. It is also possible to provide one or more openings in the surface of the impact plate ( Figures 9f, 9g and 9h ). Finally, it is also possible to bevel the upper corners of the baffle plate ( Figure 9i ) or to be provided with indentations ( Figure 9e ). It has been shown that, despite the different shapes, the effect of deflecting or directing the primary air flow to the suction opening is maintained by the secondary air flow.

In figure 10 a third embodiment of the kitchen appliance 1 according to the invention is shown. This third embodiment differs from that in figure 1 shown first embodiment, only the configuration of the exhaust channel 210. In the third embodiment, instead of a horizontally lying exhaust channel 210, two vertically extending exhaust channels 210 are provided. The blow-out channels 210 are located on the side of the baffle plate 220 that faces away from the suction opening 20 . The blowout channels 210 are provided on the outer lateral edges of the baffle plate 220 . The exhaust openings 21 are located on the respective exhaust channel 210 on the side that faces outwards. Thus, also in the third embodiment, a secondary air flow S is discharged to the outside to the sides. in the in figure 10 shown embodiment, the exhaust openings 21 are designed so that the secondary air flow S is discharged upwards in a fan shape. However, it is also within the scope of the invention for the exhaust openings 21 to be designed in such a way that the secondary air flow is discharged downwards in a fan shape. At least the lower exhaust openings 21 of the exhaust channels 210 can be directed downwards.

In figure 11 a fourth embodiment of the kitchen appliance 1 according to the invention is shown. This fourth embodiment differs from that in figure 10 shown third embodiment, only the configuration of the exhaust channel 210. In the fourth embodiment of the two vertically extending exhaust channels 210, only one vertically extending exhaust channel 210 is provided. The blow-out channel 210 is located on the side of the baffle plate 220 that faces away from the suction opening 20 . The exhaust channel 210 is arranged in the middle of the width of the baffle plate 220 and thus also in the middle of the width of the suction opening 20 . The blow-out openings 21 are located on the respective opposite, outward-facing sides of the blow-out duct 210. Thus, in the fourth embodiment too, a secondary air flow S is discharged to the sides to the outside. As in the first embodiment, the blow-out openings 21 can be designed in such a way that the secondary air flow S is blown out at an angle to the baffle plate 220 . Due to the Coanda effect, the secondary air flow hugs the baffle plate and only tears away from the baffle plate 220 at the outer edges of the latter. in the in figure 11 shown embodiment, the exhaust openings 21 are designed so that the secondary air flow S is discharged upwards in a fan shape. However, it is also within the scope of the invention for the exhaust openings 21 to be designed in such a way that the secondary air flow is discharged downwards in a fan shape. At least the lower exhaust openings 21 of the exhaust channels 210 can be directed downwards.

In figure 12 a fifth embodiment of the kitchen appliance 1 according to the invention is shown. This fifth embodiment differs from that in figure 1 In the first embodiment shown, only the configuration of the exhaust port 210. In the fifth embodiment, the exhaust port 210 has a semi-circular surface extending vertically upward. The exhaust openings 21 are located in the upper side of the exhaust duct 210 and are designed in such a way that they emit a secondary air flow S to the sides to the outside. As in the first embodiment, the blow-out openings 21 can be designed in such a way that the secondary air flow S is blown out at an angle to the baffle plate 220 . Due to the Coanda effect, the secondary air flow hugs the baffle plate and only tears away from the baffle plate 220 at the outer edges of the latter. in the in figure 12 shown embodiment, the exhaust openings 21 are designed so that the secondary air flow S is discharged upwards in a fan shape.

The present invention is not limited to the embodiments shown as examples. In particular, the shape and arrangement of the exhaust openings, the baffle plate and the suction opening can deviate from the embodiments shown. The embodiments shown in the figures can be combined with one another. For example, the type of suction opening and the separating element from the second embodiment can be combined with each of the blow-out variants of the third to fifth embodiment.

In any case, however, the directed secondary air flow will guide and, in particular, deflect the fumes in such a way that they reach the intake openings in a targeted manner. The exhaust air flow, i.e. the primary air flow, is sucked in at the front of the baffle plate and the directed secondary air flow is blown out behind the baffle plate. The volumetric flow in the space above the cooktop can be regulated from above, from the front and from behind thanks to the targeted air flow. The suction can take place in front of a baffle plate. A similar function exists when the position of the secondary fluid nozzle or the suction is changed and the target volume flow of the secondary fluid is maintained.

According to the invention, it is therefore possible to reduce the required suction power and thus the noise development.

The present invention has a number of advantages. With the present invention, the fume extraction behavior can be improved and noise minimization and an increase in energy efficiency can be achieved through a lower required delivery volume of table ventilation. In particular, very good extraction, ie vapor trapping rate, can be achieved on cooktops that are further away from the suction area of the extraction opening and even with tall pots. Today's hob ventilation can only draw in vapors over a limited distance. The distance of about 380 - 450 mm to the front cooking zone of a four-zone hob cannot be covered with the usual delivery volumes, i.e. the vapors produced on the front cooking zone cannot be extracted. This problem does not occur with the present invention due to the targeted secondary air routing. In addition, interference-free suction against cross flows is guaranteed. Furthermore, a lower motor power of the blower is required and thus the noise development is minimized even with a higher suction power. Finally, with the present invention, no additional cutouts and/or installation spaces around the cooktop are required, since the exhaust openings, optionally a baffle plate and optionally an additional fan can be built into the vapor extraction device.

REFERENCE MARKS

1

kitchen utensil

2

extractor device

20

suction port

21

exhaust port

210

exhaust channel

22

separator

220

flapper

221

suction body

23

Housing

3

hob

30

cooking zone

G

cooking vessel

S

secondary airflow

P

primary fluid flow

W

whirl

Claims (24)

Vapor extraction device with an extraction opening (20) and a blower which is arranged under the extraction opening (20) and via which the primary air (P) is sucked off downwards via the extraction opening (20), characterized in that the vapor extraction device (2) has at least one exhaust opening (21 ) which is adjacent to the suction opening (20) and through which a directed secondary air flow (S) is blown out. Vapor extraction device according to Claim 1, characterized in that at least one exhaust opening (21) lies in the horizontal. Vapor extraction device according to claim 1 or 2, characterized in that at least one exhaust opening (21) is vertical. Vapor extraction device according to one of Claims 1 to 3, characterized in that at least one exhaust opening (21) is inclined to the vertical and horizontal. Vapor extraction device according to one of Claims 1 to 4, characterized in that at least one exhaust opening (21) is directed upwards. Vapor extraction device according to one of Claims 1 to 5, characterized in that the exhaust opening (21) lies above the level of the suction opening (20) and is inclined downwards. Vapor extraction device according to one of Claims 1 to 6, characterized in that the at least one exhaust opening (21) is provided on an exhaust channel (210) which extends upwards from the plane in which the suction opening (20) is located. Vapor extraction device according to Claim 7, characterized in that the at least one exhaust channel (210) is arranged in the middle or at the lateral ends of the width of the extraction opening (20). Vapor extraction device according to one of Claims 1 to 8, characterized in that the vapor extraction device (2) has a separating element (22) which is arranged between the suction opening (20) and the at least one exhaust opening (21). Vapor extraction device according to Claim 9, characterized in that the separating element (22) extends vertically upwards from the plane of the suction opening (20). Vapor extraction device according to one of Claims 9 or 10, characterized in that the separating element (22) is an impact plate (220). Vapor extraction device according to Claim 11, characterized in that the baffle plate (220) has a thickness in the range from 2 mm to 20 mm. Vapor extraction device according to one of Claims 9 or 10, characterized in that the separating element (22) is a suction body (221) which has at least one suction opening (20) on the side facing away from the at least one exhaust opening (21). Vapor extraction device according to one of Claims 1 to 13, characterized in that the vapor extraction device (2) has an additional fan which is connected to the at least one exhaust opening (21). Kitchen appliance with hob (3) and at least one extractor device (2), characterized in that the at least one extractor device (2) is an extractor device (2) according to one of Claims 1 to 14 and the suction opening (20) in the horizontal direction between the at least an exhaust opening (21) and the hob (3) is arranged. Kitchen appliance according to claim 15, characterized in that the at least one vapor extraction device (2) is arranged behind the hob (3). Kitchen appliance according to one of Claims 15 or 16, characterized in that the extractor device (2) has a separating element (22) and the width of the separating element (22) corresponds to the width of the hob (3). Method for operating an extractor device according to one of Claims 1 to 14, characterized in that at least one secondary air flow (S) is discharged via the at least one exhaust opening (21) in such a way that the at least one secondary air flow (S) is discharged via the sides of the suction opening (20 ) is directed outwards. Method according to Claim 18, characterized in that the secondary air flow (S) is aligned in such a way that it lies in a plane which is parallel to a plane in which the longitudinal extension of the suction opening (20) lies. Method according to one of Claims 18 or 19, characterized in that the secondary air is discharged in a fan shape. Method according to Claim 20, characterized in that the secondary air (S) flows upwards at least in the edge area of the upper edge of the separating element (22) and in the central area of the upper edge of the separating element (22) the secondary air flow forms at least one vortex (W), the center of which lies in front of the separating element (22). Method according to one of Claims 18 to 21, characterized in that the secondary air flow (S) is discharged in such a way that it is directed at least in some areas from behind onto a separating element (22), flows along the separating element (22) and from the lateral edge of the separating element (22) breaks off and flows laterally outwards. Method according to one of Claims 18 to 22, characterized in that the speed of the secondary air flow (S) is greater than the speed of the primary air flow (P) at the suction opening (20). Method according to one of Claims 18 to 23, characterized in that the average outlet speed of the secondary air (S) at the outlet opening (21) is in the range of 6 to 7 m/s at a secondary air volume flow of 120 to 150 m ³ /h.

Images