Extractor hood, kitchen appliance with hob and extractor hood and method for operating an extractor hood

Description

[0001] The present invention relates to a kitchen appliance with a hob and extractor hood and a method for operating an extractor hood.

[0002] To clean fumes and vapors created when cooking on a hob, it is common practice to use extractor hoods that are mounted above the hob, for example, on a room wall. These extractor hoods extract the fumes and vapors upwards. Also known as downdraft extractors or tabletop extractors, which can also be referred to as hob extractors, are also known, in which fumes and vapors are extracted downwards. One embodiment of a downdraft extractor is described, for example, in DE 10 2010 042 436 A1. This downdraft extractor uses an extraction unit with a vertical extraction opening that can be extended vertically from the hob.

[0003] Further extractor hoods are described, for example, in DE 10 2017 216 456 A1, WO 2014 031 080 A1, US 2013 042 853 A1 and CN108224517A.

[0004] With cooktop extractors, rising vapors are drawn downwards or sideways against the force of physical buoyancy. This requires high air speeds and extraction power, which result in high noise levels. Vapor capture is either not achieved when the cooking vessel is far away from the extraction opening, or the vapor capture rate is low. Furthermore, most cooktop extractors have difficulty capturing rising vapors from taller cooking vessels, such as pots. If crossflows occur in the room, vapor capture is significantly reduced.

[0005] The invention is therefore based on the object of creating a solution with which the vapor extraction performance of a cooktop ventilation system can be improved with a lower required flow volume.

[0006] The invention is based on the finding that this can be achieved by targeted air guidance of a secondary air flow, which influences the sucked-in vapors at least in the vicinity of the extraction opening.

[0007] According to the invention, the object is therefore achieved by a kitchen appliance having the features of feature 1.

[0008] An extractor hood 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 extractor hood preferably has at least one filter element for cleaning the air. In particular, at least one grease filter and, if appropriate, an odor filter can be provided in the extractor hood. The extractor hood has an extraction opening. According to the invention, several extraction openings can also be provided on the extractor hood. In the following, however, the invention is described essentially with reference to an extractor hood with only one extraction opening. A fan is arranged below the extraction opening. Several fans can also be provided in the extractor hood.In the following, however, the invention will be described essentially with reference to an extractor device with a fan. The fan can also be referred to as a ventilator or suction fan. The fan draws air downward through the extraction opening. The extracted air is referred to as primary air and represents, in particular, contaminated air in the form of fumes and vapors. The extractor device thus represents a cooktop ventilation system, which can also be referred to as a downdraft ventilation system or table ventilation system.

[0009] The extractor hood is characterized in that it has at least one exhaust opening adjacent to the extraction opening and through which a directed secondary air stream is blown out. The at least one exhaust opening can be designed in the form of a hole or a slot. However, it is also within the scope of the invention for the at least one exhaust opening to be formed by a pipe end or an opening in the casing wall of a pipe. In this case, the exhaust opening can also be referred to as a nozzle. The air can be guided from the fan to the at least one exhaust opening by means of a duct, which can have a round or rectangular cross-section (flat duct). The exhaust opening is arranged adjacent to the extraction opening.Adjacent to the extraction opening is an exhaust opening which, in the horizontal direction, is located a short distance from the extraction opening and is preferably adjacent to the extraction opening and is only possibly separated from the extraction opening by a separating element. In the vertical direction, the at least one exhaust opening can be located in the plane of the extraction opening or, particularly in the case of a so-called downdraft extractor device with an extraction body with an extraction opening, can be offset downwards in the vertical direction relative to the extraction opening. The extraction opening is preferably located horizontally between the space from which air is to be extracted, in particular the space above a hob, and the at least one exhaust opening.

[0010] A directed secondary air stream is discharged through at least one outlet opening. The secondary air stream is also referred to below as the supply air stream, secondary air stream, or secondary fluid stream. The secondary air can be fresh air from the room in which the extractor fan is operated, fresh air from outside the room, or vapors and fumes extracted from the room and preferably cleaned. A directed air stream is an air stream that, due to the geometry of the outlet opening and / or the speed at which the air stream is discharged, flows in a predetermined direction, at least over a certain distance.

[0011] By providing at least one exhaust opening adjacent to the extraction opening according to the invention, through which a directed secondary air flow can be blown out, the direction and speed of the primary air flow, which are determined by the fan and the thermal conditions on a cooktop, can be specifically changed or supported in at least individual areas. In particular, the primary air flow can be directed to the extraction opening. This can increase the volume flow sucked in via the extraction opening and / or reduce the demand on the fan to extract the primary air. Thus, the present invention can increase the vapor capture rate and thus the efficiency of the extractor hood. In addition, the fan can be operated at lower power or a smaller fan, i.e. a fan with a lower rated power, can be used.This reduces the noise generated when extracting the primary air and lowers energy consumption.

[0012] If multiple exhaust openings are provided on the extractor, 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. Furthermore, it is also possible for each exhaust opening to be aligned in a different direction.

[0013] According to one embodiment, at least one exhaust opening is located horizontally. With this arrangement of the at least one exhaust opening, the secondary air can be discharged vertically upwards.

[0014] Unless otherwise stated, directions such as top, bottom, front, and rear refer to an extractor hood when installed behind a hob. The direction "front" of the extractor hood refers to the side of the extractor hood facing the hob. For ease of reference, Figure 3 A coordinate system is specified, to which reference is made below. The x-axis is horizontal and extends in the depth direction of the extractor hood and a hob arranged in front of the extractor hood. The y-axis is also horizontal, extends perpendicular 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 extractor hood and is perpendicular to the x- and y-axes.

[0015] By placing at least one exhaust opening horizontally, the secondary air can be discharged through the exhaust opening in a direction that has at least a vertical component and is directed vertically upwards, for example. Furthermore, the horizontal position of the at least one exhaust opening can simplify the design of the extractor hood. In particular, the exhaust opening(s) can be positioned at a height corresponding to the height of the hob. This eliminates the need for a separate exhaust duct extending across the top of the hob.

[0016] According to a further embodiment, at least one exhaust opening is positioned vertically. This orientation allows a secondary air flow to be discharged through the at least one exhaust opening, which has at least a horizontal directional component. For example, the secondary air flow can be discharged horizontally. In particular, a secondary air flow directed toward one of the sides of the extractor hood and thus toward one of the sides of the cooktop can be generated via the vertical exhaust opening.

[0017] According to a further embodiment, at least one exhaust opening is inclined relative to the vertical and horizontal planes. With this arrangement, the exhaust opening can be configured, for example, as a hole or a slot through which secondary air is discharged in a direction transverse to the horizontal and vertical planes. 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 stream can thus be discharged upwards through these exhaust openings. Instead of a simple hole or slot, the exhaust opening can also be a nozzle.

[0018] As already mentioned above, when providing several exhaust openings, the orientations of the individual exhaust openings to each other can be the same or different.

[0019] According to a further embodiment, at least one exhaust opening is directed upwards. In this case, an exhaust opening through which secondary air can be discharged in a direction with a vertically upward directional component is referred to as upwardly directed. The direction of the exhaust opening can be determined by its arrangement on the extractor hood and, if appropriate, also by its geometry. For example, a horizontal exhaust opening can be formed by a bore or hole that is inclined to the vertical. Thus, a secondary air stream that flows transversely upwards can be discharged through this horizontal exhaust opening. By directing the exhaust direction upwards, the secondary air can form an air curtain that demarcates the area above the hob. In addition, the primary air above the level of the hob can be specifically influenced.In particular, at least a portion of the primary air can be entrained against the main intake direction of the exhaust opening. The resulting effect is explained in more detail below.

[0020] According to a further embodiment, the exhaust opening is located above the level of the extraction opening and is inclined downwards. In an embodiment in which the extractor hood is a downdraft extractor hood with a vertical extraction opening, the exhaust opening can be located above the level at which the extraction body protrudes upwards from the housing of the extractor hood, in particular above the level of the hob, and can be inclined downwards. A blow-out opening is referred to as being inclined downwards if it can discharge secondary air in a direction that has at least one downward directional component. The blow-out opening is preferably oriented such that the secondary air always has a horizontal directional component, i.e. is not discharged vertically downwards.Through a downward-sloping exhaust opening, the secondary air can at least partially influence the primary air in the direction of the extraction opening.

[0021] The at least one exhaust opening can be provided on an exhaust duct. The exhaust duct can be provided in the extractor extraction device such 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 plane preferably corresponds to the plane of the extraction opening. In one embodiment in which the extractor extraction device is a downdraft extractor extraction device, the plane of the extraction opening lies above the plane of the hob and any worktop that may be provided. In this embodiment, the exhaust duct is arranged in one embodiment such that the upper side of the exhaust duct lies in the plane of the hob and, if applicable, the worktop.

[0022] According to one embodiment, the at least one exhaust opening is provided on an exhaust duct which extends upwards from the plane in which the extraction opening is located. The plane in which the extraction opening is located is preferably the plane of the hob. In an embodiment in which the extractor hood is a downdraft extractor hood, the plane of the extraction opening is above the plane of the hob and any worktop provided. In this embodiment, the exhaust duct extends upwards from the plane of the hob and, if present, the worktop. By having the exhaust duct extend upwards above the plane of the hob and preferably above the plane of the extraction opening, the targeted influencing of the primary air generated above the hob can be easily ensured, since the exhaust openings can be arranged at a certain height above the hob.

[0023] The extraction opening preferably has a width corresponding to the width of the cooking surface from which the primary air is to be extracted. Preferably, the width, i.e. the extension of the extraction opening in the Y-direction, is greater than its depth, i.e. its extension in the X-direction of the Figure 3 defined coordinate system.

[0024] 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 extraction opening. Alternatively, two exhaust ducts are provided, which are arranged at the lateral ends of the width of the extraction opening. In both cases, the exhaust duct is adjacent to the extraction opening and preferably offset to the rear. When the exhaust duct is arranged in the middle of the width of the extraction opening, exhaust openings are preferably provided on both sides of the exhaust duct that lie in the width direction, i.e. the Y direction. In the embodiment in which two exhaust ducts are provided, one each arranged at a lateral end of the width of the extraction opening, exhaust openings are only provided in one side of the respective exhaust duct.

[0025] According to a preferred embodiment, the extractor extraction device has a separating element arranged between the intake opening and the at least one exhaust opening. The separating element is preferably a flat element that extends across the entire width of the extraction opening. By providing a separating element, direct suction of secondary air into the extraction opening can be prevented, even at low secondary air speeds, particularly when the at least one exhaust opening is arranged in the plane of the extraction opening. However, with sufficient speed and, if appropriate, suitable orientation of the secondary air flow, it is also possible for there to be no separating element between the extraction opening and the at least one exhaust opening.Mixing of the secondary air and the primary air below the level of the extraction opening can be prevented by the rear wall of an extraction duct, the top of which forms the extraction opening, and / or the front wall of an exhaust duct.

[0026] Preferably, the separating element extends vertically upward from the plane of the intake opening. This guides the secondary air jet emitted from an exhaust opening behind the separating element at least along the path over which the secondary air flow flows along the separating element. Furthermore, a vertically upwardly extending separating element reliably prevents the direct intake of secondary air into the exhaust opening.

[0027] According to one embodiment, the separating element is a baffle plate. The baffle plate can be movably attached to the extractor device; in particular, the baffle plate can be retracted into and out of the housing of the extractor device. This allows different heights of cooking vessels to be taken into account, or the baffle plate can be retracted when the extractor device is not in use. Alternatively, the baffle plate can also be fixedly attached to the extractor device. The baffle plate can be a disc, for example made of glass, plastic, or metal. By using a baffle plate as a separating element, the distance between the flow in front of the baffle plate and the flow behind the baffle plate is small. This allows the two flows to influence each other at the edges of the baffle plate.In particular, when using a thin separating element, especially a baffle plate, no undesirable turbulence occurs at the edges of the baffle plate.

[0028] The impact plate preferably has a thickness in the range of 2 mm to 20 mm. The thickness of the impact plate is particularly preferably in the range of 5 to 10 mm, especially 6 mm. It has been shown that with an impact plate of this thickness, the targeted formation of vortices at the upper edge of the impact plate can be achieved, or at least this is promoted. The vortices also direct the primary air flow toward the extraction opening.

[0029] 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 exhaust opening. The suction body can also be referred to as a suction duct. In the embodiment in which the separating element represents a suction body, the extractor device is a so-called downdraft extractor device. The suction body can be fixedly or movably attached to the housing of the extractor device. The suction body preferably has a shallow depth.

[0030] The secondary air flow discharged through the at least one exhaust opening can be generated by the fan of the extractor device. In particular, a portion of the primary air drawn in through the extraction opening and optionally purified in the extractor device can be diverted via a bypass and fed to the exhaust openings. This creates a variable secondary air flow, i.e., a flow dependent on the primary air flow. In this embodiment, the speed of the secondary air flow can optionally be additionally determined by the geometry of the exhaust openings.

[0031] According to one embodiment, a portion of the exhaust air flow can thus be used to advantageously influence the vapors. A portion of the air, possibly purified of grease and odors, can be extracted from the exhaust air flow via a bypass. For the purposes of the present invention, the exhaust air flow refers to the air flow that has been extracted and purified by the extractor device. This air can alternatively be returned to the room in which the extractor device is operated or released into the environment. The extractor device can therefore be designed as an exhaust air or recirculation extractor device.

[0032] According to one embodiment, the extractor device has an additional fan connected to the at least one exhaust opening. In this embodiment, fresh air can be drawn in from the room in which the extractor device is operated or from the surroundings and expelled as a secondary air flow from the exhaust openings. In this embodiment, a constant secondary air flow can thus be generated. The additional fan can, for example, draw in a fresh air flow from the furniture base cabinet to beneficially influence the vapors. In this case, clean air is drawn in from the kitchen base cabinet. Alternatively, clean air can be drawn in from outside.

[0033] Advantages and features described with regard to the extractor device also apply - where applicable - to the kitchen appliance according to the invention and vice versa and are therefore only described once if necessary.

[0034] The kitchen appliance comprises a hob and at least one extractor device. The hob and the extractor device can be installed in a worktop. The hob and the extractor device(s) can be installed in a common recess in the worktop. However, it is also within the scope of the invention for the at least one extractor device and the hob to be installed in separate recesses in the worktop. Preferably, the at least one extractor device is provided at an edge of the hob such that the extraction opening of the extractor device extends along the edge of the hob.

[0035] Furthermore, according to the invention, the extraction opening is arranged horizontally between the at least one exhaust opening and the hob. This means that the extraction opening is closer to the hob than the at least one exhaust opening. Furthermore, the primary air flow, which is drawn in through the extraction opening, is influenced near the extraction opening. Thus, the invention differs from extractor devices in which an air supply flow is generated on the side of the hob opposite the extraction opening and is directed toward the extraction opening.

[0036] According to a preferred embodiment, the at least one extractor device is arranged behind the hob. An extractor device is referred to as being arranged behind the hob in which the extraction opening and the at least one exhaust opening are arranged in the negative X-direction in the coordinate system according to Figure 3In this position, for example, in the case of a cooktop installed on a cooking island, an air curtain can be formed behind the cooktop, thus preventing the flow conditions above the cooktop from being influenced from behind.

[0037] According to one embodiment, the extractor device has a baffle plate, which serves as a separating element between the extraction opening and the at least one exhaust opening. The width of the baffle plate corresponds, for example, to the width of the cooktop. This ensures targeted shielding of the extraction opening, which preferably also corresponds to the width of the cooktop.

[0038] According to the invention, the invention relates to a method for operating the extractor device of the kitchen appliance according to the invention. The method is characterized in that at least one secondary air stream is discharged through the at least one exhaust opening in such a way that the at least one secondary air stream is directed outward via the sides of the exhaust opening.

[0039] 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 be a continuous curtain or formed from individual secondary air flows. In the latter case, the speed of the air can vary slightly across the air curtain. The secondary air flow is directed outwards at least over the sides of the extraction opening. The longitudinal ends of the preferably elongated extraction opening are referred to as the sides of the extraction opening. The secondary air flow is therefore directed in the width direction of the extraction opening and thus also in the width direction of the extractor hood and the hob. Due to this orientation of the secondary air flow, it is perpendicular to the main direction of the primary air flow, which is drawn from the hob towards the extraction opening by the fan.This can, on the one hand, prevent fumes from escaping to the rear, as the secondary air flow can act as an air curtain and shield the area above the cooktop to the rear. On the other hand, the direction of the secondary air flow, which is perpendicular to the flow direction of the primary air flow in the negative x-direction, can cause at least part of the primary air flow to be entrained by the secondary air flow. For reasons of continuity, the entrained part of the primary air flow causes additional primary air to flow towards the extraction opening and can be sucked into the extraction opening by the fan of the extractor fan. The secondary air flow can, at least in some areas, be directed upwards or downwards in addition to being directed outwards.

[0040] When a baffle plate is provided, the air curtain is preferably formed parallel to the baffle plate, essentially forming an extension of the baffle plate on both sides and diagonally upwards. It separates the lateral areas in front of and behind the baffle plate. This also prevents a large amount of primary air from being extracted from the sides.

[0041] Advantages and features that are and have been described with regard to the method according to the invention also apply - where applicable - to the extractor hood device according to the invention and the kitchen appliance according to the invention and vice versa and are therefore described only once if necessary.

[0042] According to one embodiment, the secondary air flow is aligned such that it lies in a plane that is parallel to a plane in which the longitudinal extent of the extraction opening lies. According to the invention, however, it is also possible for the secondary air flow to be directed in a direction that is inclined forwards, in particular towards the hob. However, this inclination of the secondary air flow is preferably slight and in particular less than 90°, preferably less than 45°. According to one embodiment, the secondary air flow can be output such that it is directed at least partially from the rear onto a separating element, flows along the separating element and breaks off from the lateral edge of the separating element and flows laterally outwards.

[0043] According to a preferred embodiment, the secondary air is discharged in a fan shape. A secondary air stream discharged from one outlet opening can be fanned out. Alternatively, secondary air streams from multiple outlet openings can combine to form a fan shape.

[0044] According to one embodiment, the secondary air flows upwards at least in the edge region of the upper edge of the separating element, and the secondary air flow forms at least one vortex in the central region of the upper edge of the separating element. The center of the at least one vortex lies in front of the separating element. By placing the center of the vortex in front of the separating element, the latter can, on the one hand, reliably prevent primary air from escaping upwards and, on the other hand, direct rising primary air downwards towards the extraction opening at an early stage, thus assisting extraction. Preferably, two symmetrical vortices are formed. Particularly in the case of an air flow that is divided into two compartments, a vortex preferably forms on each of the sides of the respective compartment part that face each other, i.e. between which no secondary air flows upwards. The vortices are therefore located in the central region of the width of the upper edge of the impact plate.The two vortices can be separated from each other across the width of the impact plate or form a single vortex. The axis of the vortex(s) is parallel to the impact plate.

[0045] The velocity of the secondary air flow is preferably greater than the velocity of the primary air flow at the extraction opening. This prevents the secondary air from being directly sucked into the extraction opening, even without a separating element.

[0046] According to one embodiment, the average outlet velocity 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 m³ / h. For example, an outlet velocity of the secondary air can be set in the range of 6 to 7 m / s at a volume flow in the range of 130 to 150 m³ / h. The outlet velocity here refers to the vertical velocity component. The outlet velocity can be higher by changing the geometry of the outlet opening, in particular of nozzles with a smaller outlet opening, or lower for nozzles with a larger outlet opening. The outlet velocity indicates an average outlet velocity, whereby the outlet velocity can be unevenly distributed across the outlet opening or nozzles provided therein.If low outlet velocities are used, a high volume flow is preferably set in order to continue to achieve advantages of the invention.

[0047] With the present invention, targeted air guidance and influencing of the primary air can be achieved in a simple manner, for example by adjusting the parameters of the thickness of the baffle plate, the extraction power of the fan, the size and position of the extraction opening, the height of the baffle plate, as well as the volume flow, the speed, and the direction of the secondary air flow. In particular, at least one secondary air vortex can form on the upper side of the baffle plate, which can prevent the primary air from escaping and passing over the upper edge of the baffle plate and also assists the intake of the primary air.

[0048] The present invention will be described again below with reference to the accompanying figures. They show: Figure 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- without and with 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 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 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 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 perspective view; Figure 9 : 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 : 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 Figure 13 with a tangential projection of the velocity vectors.

[0049] In Figure 1A first embodiment of the kitchen appliance 1 according to the invention is shown. The kitchen appliance 1 comprises a hob 3 and an extractor hood 2. The extractor hood 2 comprises an extraction opening 20 and a plurality of exhaust openings 21. The exhaust openings 21 are formed in the top of an exhaust duct 210. A separating element 22 in the form of a baffle plate 220 is arranged between the exhaust openings 21 and the extraction opening 20. The extractor hood 2 further comprises a fan (not shown) via which air is sucked into the extraction opening 20. In addition, the extractor hood 2 can comprise an additional fan (not shown) via which air is directed to the at least one exhaust opening 21.

[0050] The extractor device 2 further comprises a housing 23, of which Figure 1only a cover is visible. The cooking surface 3 is arranged in front of the extraction opening 20. A cooking vessel G in the form of a pot is shown schematically on the cooking surface 3.

[0051] As can be seen from Figure 1 In the first embodiment of the cooking appliance 1, the secondary fluid flow S is discharged in a fan-shaped manner. The secondary air flow S can, as shown, be blown out from the outlet openings 21 in the direction of the baffle plate 220. For the effect according to the invention, the type of generation of the secondary volume flow for the secondary air flow S and the presence or geometry of the baffle plate 220 are irrelevant.

[0052] Secondary air is blown out of the blow-out duct 210 through the blow-out openings 21. It is also within the scope of the invention that the blow-out duct 210 has only one blow-out opening 21, which extends over the entire length of the top side of the blow-out duct 210. The blow-out takes place as in Figure 1shown near the baffle plate 220. The secondary air can initially be discharged through the outlet opening 21 in the direction of the baffle plate. Due to its proximity to the baffle plate 220, the fan-shaped secondary volume flow S adheres to the baffle plate 220. This effect is also referred to 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 cooktop, and the secondary fluid flow S thus breaks off. Outside the baffle plate 220, a boundary layer flow develops between the secondary fluid flow S. The boundary layer flow also exists without the presence of a solid boundary. Air friction entrains the primary fluid and directs it in the desired direction toward the extraction opening. Due to the mass movement of the primary fluid towards the separation edge, the primary fluid is divided in the direction of extraction and in the opposite direction to the extraction (following the secondary fluid).A continuous flow develops, directing the primary fluid from the front and upper areas of the cooktop toward the extraction system.

[0053] In addition, the secondary fluid flow S forms an air curtain, which makes air flow from the area in front of the baffle plate 220 to the area behind the baffle plate 220 considerably more difficult.

[0054] The effects on the 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 the Figures 4 to 8 described in more detail.

[0055] In the Figure 2A second embodiment of the cooking appliance according to the invention is shown. The second embodiment differs from the first embodiment only in that, instead of a baffle plate 220, a suction body 221 is provided as a separating element 22. The suction body 221 represents a hollow, upwardly closed body, which can also be referred to as a duct. The suction opening 20 of the extractor device 2 is formed in the upper region of the side of the suction body 221. Air can be sucked into the fan (not shown) located below the level of the cooking surface 3 via the hollow suction body 221. In this embodiment too, the secondary fluid flow S, which is blown out through the blow-out openings 21, forms a fan that extends at least beyond the lateral edges of the suction body 221. Thus, in the second embodiment according to Figure 2a dragging 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.

[0056] In Figure 3 The geometry of one embodiment of the cooking appliance is shown with reference planes. In Figure 3aThe outlet shape of the mass flow of the secondary fluid is shown. As can be seen from this illustration, the secondary air flow S forms a fan that extends along the rear side of the baffle plate 220 to the sides of the baffle plate 220 and projects beyond. In the vertical direction, the mass flow is low. However, it is also within the scope of the invention for the secondary fluid flow S to also be directed upwards and extend beyond the top side of the baffle plate. The velocity of the secondary fluid flow is higher near the outlet opening and decreases with increasing distance from the outlet opening. In particular, the velocity decreases once it reaches the edges of the baffle plate 220.

[0057] In the Figures 4 to 8 The flow conditions are determined by different reference levels of the Figure 3 shown in different representations. The flow conditions are shown with and without secondary air flow.

[0058] Excessive volume flow from the sides of the extraction opening (Y+ and Y- planes) to the extractor has a negative impact on the vapor capture rate. This type of flow can occur, for example, due to air being drawn in around the cooktop. The primary volume flow from the sides, on the other hand, has only a minor impact on the vapor capture rate and consumes a large portion of the total required extraction power of the fan.

[0059] 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. As can be seen from Figures 4a and 4bAs a result, the secondary air flow in its front area entrains mass of the primary air flow as soon as the secondary air flow passes the edge of the baffle plate. For continuity reasons, mass of the primary fluid must flow in. This results in the lateral outer area being separated from the inner area by an air curtain created by the primary fluid. The outer rear area, i.e. 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 a portion of the mass of the primary fluid is entrained by the secondary fluid.

[0060] 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 5bShow representations of the flow conditions through the lateral planes Y+ and Y- without and with secondary air flow as velocity vectors along streamlines in perspective view. As can be seen from these figures, a more targeted suction of the primary fluid is achieved.

[0061] 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 perspective view. As can be seen from Figure 6a A large part of the primary air flow comes from the area behind the hob, especially behind the baffle plate. This air flow is undesirable because, if the extraction power is too weak, it cannot carry the vapors that form on the hob downwards and consumes part of the total extraction power. Figure 6aIn contrast, the flow conditions through the rear plane X- are shown. Here, it is evident that the leakage flow from the area behind the cooktop, and especially 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 continuity reasons. This already occurs at the separation point at the edge of the baffle plate. This forces the primary fluid to flow toward the extraction opening and the baffle plate, even in the distant upper area. Furthermore, the secondary fluid acts as an air curtain, preventing the primary fluid from being sucked in from behind the baffle plate.

[0062] In the Figures 7a and 7bRepresentations of the flow conditions through the upper plane Z+ with and without secondary air flow are shown as velocity vectors along streamlines in perspective view. In particular, this shows the flow conditions near the cooking vessel G. The primary volume flow is deflected downwards toward the extraction opening and baffle plate by the effect of the secondary air jet.

[0063] From the Figures 8a and 8b , which depict the flow conditions through the front plane X+ without and with secondary air flow as velocity vectors along streamlines in a perspective view, shows that the effect of the secondary air flow also has an impact in the front area of ​​the cooktop. The primary air flow, modified by the secondary volume flow, counteracts the naturally rising thermals of the vapor and draws it toward the baffle plate to the extraction opening.

[0064] In the Figure 13aThe outlet shape of the mass flow of the secondary fluid in one embodiment of the fume extraction device is shown. As can be seen from this illustration, the secondary air flow S forms a fan that extends along the rear side of the baffle plate 220 to the sides of the baffle plate 220 and projects beyond. In the vertical direction, the mass flow is lower. In particular, the fan of the secondary air flow splits.

[0065] By breaking off the secondary air flow S at the upper edge of the baffle plate 220 and extracting the primary air flow (in Figure 13anot shown) in front of the baffle plate 220, two vortices W are formed. The vortices W are created by a rolling up of the secondary air flow as soon as it passes the upper edge of the baffle plate 220. Ideally, the vortices W are stationary. The vortices W create an additional component that deflects the rising vapor, i.e. the primary air flow, downwards towards the extraction opening at an early stage. This is shown in Figure 13bshown schematically, which shows 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 baffle plate 220. This illustration shows the vortex formation at the upper edge of the baffle plate 220, 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 region of the baffle plate 220. In addition, the vapor in the outer region of the baffle plate 220 is prevented from being entrained by the secondary air flow.

[0066] The exact shape of the baffle plate is not important. However, a minimum height can be advantageous to separate the primary flow from the secondary flow, so that no primary fluid containing vapors is entrained in the lower area. The height and width of the baffle plate are not crucial for the functional principle. However, different optimal dimensions can be selected for different applications, for example, the height of the baffle plate depends on the pot height, or the width depends on the hob width. As already explained, the shape of the separating element, and in particular the baffle plate, has no influence on the effect of the secondary air flow. Therefore, different types and shapes of baffle plates can be used. Figure 9 Different forms of impact plates are shown schematically. As can be seen from Figure 9 Indentations ( Figures 9b, 9c and 9d) may 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 chamfer the upper corners of the impact plate ( Figure 9i ) or to provide them with recesses ( Figure 9e ). It has been shown that, despite the different shapes, the effect of diverting or directing the primary air flow to the extraction opening is maintained by the secondary air flow.

[0067] In Figure 10 A third embodiment of the kitchen appliance 1 according to the invention is shown. This third embodiment differs from the one shown in Figure 1In the first embodiment shown, only the design of the exhaust duct 210 is different. In the third embodiment, instead of a horizontally arranged exhaust duct 210, two vertically extending exhaust ducts 210 are provided. The exhaust ducts 210 are located on the side of the baffle plate 220 that faces away from the suction opening 20. The exhaust ducts 210 are provided on the outer lateral edges of the baffle plate 220. The exhaust openings 21 are located on the respective exhaust duct 210 on the side that faces outwards. Thus, in the third embodiment, a secondary air flow S is also discharged to the sides outwards. In the Figure 10In the embodiment shown, the exhaust openings 21 are designed such that the secondary air flow S is discharged upwards in a fan-shaped manner. However, it is also within the scope of the invention for the exhaust openings 21 to be designed such that the secondary air flow is discharged downwards in a fan-shaped manner. At least the lower exhaust openings 21 of the exhaust ducts 210 can be directed downwards.

[0068] In Figure 11 A fourth embodiment of the kitchen appliance 1 according to the invention is shown. This fourth embodiment differs from the one shown in Figure 10In the third embodiment shown, only the design of the blow-out duct 210 is different. In the fourth embodiment, of the two vertically running blow-out ducts 210, only one vertically running blow-out duct 210 is provided. The blow-out duct 210 is located on the side of the impact plate 220 that faces away from the suction opening 20. The blow-out duct 210 is arranged in the middle of the width of the impact 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. As in the first embodiment, the blow-out openings 21 can also be designed such that the secondary air flow S is blown out at an angle towards the impact plate 220.The secondary air flow clings to the baffle plate due to the Coanda effect and only breaks away from it at the outer edges of the baffle plate 220. In the . Figure 11 In the embodiment shown, the exhaust openings 21 are designed such that the secondary air flow S is discharged upwards in a fan-shaped manner. However, it is also within the scope of the invention for the exhaust openings 21 to be designed such that the secondary air flow is discharged downwards in a fan-shaped manner. At least the lower exhaust openings 21 of the exhaust ducts 210 can be directed downwards.

[0069] In Figure 12 A fifth embodiment of the kitchen appliance 1 according to the invention is shown. This fifth embodiment differs from the one shown in Figure 1shown first embodiment, only the design of the exhaust duct 210. In the fifth embodiment, the exhaust duct 210 has a semicircular surface that extends vertically upwards. The exhaust openings 21 are located in the top of the exhaust duct 210 and are designed such that they discharge a secondary air flow S to the sides. As in the first embodiment, the exhaust openings 21 can also be designed such that the secondary air flow S is discharged at an angle to the baffle plate 220. The secondary air flow clings to the baffle plate due to the Coanda effect and only breaks away from it at the outer edges of the baffle plate 220. In the Figure 12 In the embodiment shown, the exhaust openings 21 are designed so that the secondary air flow S is discharged upwards in a fan shape.

[0070] The present invention is not limited to the exemplary embodiments shown. In particular, the shape and arrangement of the exhaust openings, the baffle plate, and the suction opening may differ from the illustrated embodiments. 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 any of the exhaust variants of the third to fifth embodiments.

[0071] In any case, the directed secondary air flow will direct and, in particular, deflect the vapors so that they reach the intake openings. The exhaust air flow, i.e., the primary air flow, is drawn in at the front of the baffle plate, and the directed secondary air flow is expelled behind the baffle plate. Through targeted air flow, the volume flow into the space above the cooktop can be regulated from above, front, and rear. Extraction can be carried out in a flat area in front of a baffle plate. A similar function is achieved by changing the position of the secondary fluid nozzle or the extraction system while maintaining the target volume flow of the secondary fluid.

[0072] According to the invention, it is therefore possible to reduce the required intake power and thus the noise generation.

[0073] The present invention has a number of advantages. With the present invention, vapor extraction performance can be improved, and noise can be minimized and energy efficiency increased by requiring a lower airflow from tabletop extractors. In particular, very good extraction, i.e., a vapor capture rate, can be achieved on cooktops that are located further away from the intake area of ​​the extraction opening and even with tall pots. Today's cooktop extractors can only extract vapors over a limited distance. The distance of approximately 380 - 450 mm to the front cooking zone of a four-zone cooktop cannot be overcome with conventional airflows, meaning that the vapors created in the front cooking zone cannot be extracted. This problem does not occur with the present invention due to the targeted secondary air flow. Furthermore, interference-free extraction against crossflows is guaranteed.Furthermore, the fan requires less motor power, thus minimizing noise even at higher extraction rates. Finally, the present invention eliminates the need for additional cutouts and / or installation spaces around the cooktop, as the exhaust openings, a baffle plate if required, and an additional fan if required can be installed in the extractor unit. REFERENCE SYMBOL

[0074] 1 kitchen appliance 2 Extractor unit 20 Extraction opening 21 Exhaust opening 210 Exhaust duct 22 Separator element 220 Baffle plate 221 Extractor body 23 Housing 3 hobs 30 cooking zones GGraving vessel SSecary air flow PPrimary fluid flow WVortex

Claims

1. Kitchen appliance with a cooktop (3) and at least one extractor apparatus (2), wherein the at least one extractor apparatus (2) has an extractor apparatus (2) with a suction opening (20) and, arranged under the suction opening (20), a fan by means of which the primary air (P) is sucked away downward via the suction opening (20), and wherein the extractor apparatus (2) has at least one expulsion opening (21) which is adjacent to the suction opening (20) and via which an oriented secondary air stream (S) is expelled, characterised in that the suction opening (20) is arranged in the horizontal direction between the at least one expulsion opening (21) and the cooktop (3).

2. Kitchen appliance according to claim 1, characterised in that at least one expulsion opening (21) lies in the horizontal.

3. Kitchen appliance according to claim 1 or 2, characterised in that at least one expulsion opening (21) lies in the vertical.

4. Kitchen appliance according to one of claims 1 to 3, characterised in that at least one expulsion opening (21) is tilted with regard to the vertical and horizontal.

5. Kitchen appliance according to one of claims 1 to 4, characterised in that at least one expulsion opening (21) is oriented upward.

6. Kitchen appliance according to one of claims 1 to 5, characterised in that the expulsion opening (21) lies above the plane of the suction opening (20) and is tilted downward.

7. Kitchen appliance according to one of claims 1 to 6, characterised in that the at least one expulsion opening (21) is provided on an expulsion duct (210), which extends upward from the plane in which the suction opening (20) is located.

8. Kitchen appliance according to claim 7, characterised in that the at least one expulsion duct (210) is arranged in the centre or at the lateral ends of the width of the suction opening (20).

9. Kitchen appliance according to one of claims 1 to 8, characterised in that the extractor apparatus (2) has a separating element (22), which is arranged between the suction opening (20) and the at least one expulsion opening (21).

10. Kitchen appliance according to claim 9, characterised in that the separating element (22) extends vertically upward from the plane of the suction opening (20).

11. Kitchen appliance according to one of claims 9 to 10, characterised in that the separating element (22) is a deflector plate (220).

12. Kitchen appliance according to claim 11, characterised in that the deflector plate (220) has a thickness in the range 2 mm to 20 mm.

13. Kitchen appliance according to one of claims 9 or 10, characterised in that the separating element (22) is a suction unit (221), which has at least one suction opening (20) on the side facing away from the at least one expulsion opening (21).

14. Kitchen appliance according to one of claims 1 to 13, characterised in that the extractor apparatus (2) has a supplementary fan, which is connected to the at least one expulsion opening (21).

15. Kitchen appliance according to one of claims 1 to 14, characterised in that the at least one extractor apparatus (2) is arranged behind the cooktop (3).

16. Kitchen appliance according to one of claims 1 to 15, characterised in that the extractor apparatus (2) has a separating element (22) and the width of the separating element (22) corresponds to the width of the cooktop (3).

17. Method of operating an extractor apparatus of a kitchen appliance, characterised in that the kitchen appliance is embodied according to one of claims 1 to 16, and that at least one secondary air stream (S) is output via the at least one expulsion opening (21) such that the at least one secondary air stream (S) is oriented via the sides of the suction opening (20) to the outside.

18. Method according to claim 17, characterised in that the secondary air stream (S) is aligned such that the same lies in a plane that is parallel to a plane in which the longitudinal projection of the suction opening (20) lies.

19. Method according to one of claims 17 or 18, characterised in that the secondary air is output in a fanlike shape.

20. Method according to claim 19, characterised in that the secondary air (S) flows upward at least in the perimeter area of the upper edge of the separating element (22) and the secondary air stream forms, in the central area of the upper edge of the separating element (22), at least one eddy (W), the centre of which lies in front of the separating element (22).

21. Method according to one of claims 17 to 20, characterised in that the secondary air stream (S) is output such that the same is oriented, at least in some areas, from behind on to a separating element (22), flows along the separating element (22) and flies off from the lateral edge of the separating element (22), and flows laterally to the outside.

22. Method according to one of claims 17 to 21, characterised in that the speed of the secondary air stream (S) is greater than the speed of the primary air flow (P) at the suction opening (20).

23. Method according to one of claims 17 to 22, characterised in that the average outgoing speed of the secondary air (S) at the expulsion opening (21) lies in the range 6 to 7 m / s at a volumetric flow of the secondary air of 120 to 150 m3 / h.