Patent Application
20100163012
The invention relates to an extractor hood comprising a housing with a fan arranged therein and an extraction opening for the entry of fumes into the extractor hood on the bottom of the extractor hood.
During extraction of fumes which typically occur above a cooking zone with an extractor hood, the phenomenon arises that the fumes, which are also referred to below as vapor, cannot be extracted sufficiently well by the vacuum generated in the extractor hood, especially in the edge area of the extractor hood.
To take account of this problem and especially to be able to prevent cooking fumes slipping past the front of the extractor hood, an extractor hood is proposed in DE 41 14 329 A1 in which an air curtain is generated in the edge area.
The ambient air of the fan, which means the air output from the fan, can be used to generate the air curtain. As an alternative the air curtain can be generated from the ambient air of the extractor hood. For the last-mentioned case the extractor hood possesses a supplementary fan on the front side of the extractor hood which generates the air stream.
A disadvantage of this extractor hood lies in the fact that a relatively large volume flow must be diverted from the ambient air to use the ambient air of the fan. When a supplementary fan is used the complexity of the layout of the extractor hood increases, since a separate supplementary fan is needed which leads to increased energy consumption and an increase in the noise generated.
Furthermore a method is known from DE 196 13 513 A1 for restricting, detecting and extracting fumes, dust or the like as well as a device for executing the method. In this method it is proposed, in order to use said method with extractor hoods, to direct an airflow over a curved surface, with the airflow being output through exhaust ducts which are aligned in the direction of a cooking zone located below the extractor hood. In particular the exhaust ducts are provided on the front of the extractor hood or on its underside.
A disadvantage of this known system lies in the fact that the exhaust duct and the curved surface together determine the height of the extractor hood in the area of the air curtain output.
Finally in EP 1 757 865 A2, an extractor hood is described in which a nozzle unit is provided on the front side of the main body of the extractor hood which is equipped with a curved area and a nozzle. The nozzle in this case is provided on the upper side of the curved area in order to output air in a horizontal direction to the front side of the curved area.
A disadvantage of this extractor hood lies in the fact that the horizontal emission of air from the nozzle can lead on the one hand to an irritation for the user of the extractor hood. On the other hand, which is desirable with prior art extractor hoods, the air routed at the curved area can be sucked into the extraction opening of the extractor hood immediately after leaving the curved area. Vapor flowing outwards below the curved area can by contrast not be reliably sucked in through this extractor hood.
The underlying object of the invention is thus to create an extractor hood which with a simple layout makes it possible to reliably extract fumes.
The invention is based on the idea that this object can be achieved by an air curtain being generated from the top of the vapor shield.
The object is inventively achieved by an extractor hood featuring a housing with a fan disposed therein and an extraction opening for the entry of fumes or vapor into the extractor hood on the bottom of the extractor hood. The extractor hood is characterized in that, in the top of the extractor hood in a least one region of the edge area of the extractor hood at least one air outlet gap is provided which adjoins a curved surface in the direction towards the bottom of the extractor hood.
A suction opening in the sense of this invention refers to the entry opening of which fumes enter into the extraction hood. The top of the extractor hood in the sense of the invention refers to the side of the extractor hood and especially of a vapor shield or visual screen of an extractor hood which lies opposite the side of the extractor hood on which the extraction opening is provided.
Preferably the air outlet is designed so that a stream of air is output through this in a direction which has a vertical directional component which is greater than zero. In other words the stream of air features a directional component pointing upwards. The air outlet gap can be provided this purpose at a suitable point on the extractor hood. As an alternative or in addition a stream of air directed in such a manner can be realized by a suitable geometry of the air outlet gap and/or of an air duct leading to this gap. Thus the stream of air able to be generated with the present invention differs from streams of air which are applied in a horizontal direction to a curved surface. In particular with the inventive arrangement and/or design of the air outlet gap a stream of air can be generated which forms a spoiler on the front or on the bottom of the curved surface, meaning that it is separated from the curved surface at this point. It is thus possible to generate an air curtain directed to a cooking zone or work surface arranged below the extractor hood and a direct entry of the air stream from the curved surface into the extraction opening of the extractor hood is able to be avoided.
Preferably the upper side in which the air outlet is provided lies in a horizontal plane which lies in the plane or offset in parallel below the plane in which the highest point of the curved surface is located. Through this arrangement of the air outlet the explicit routing of the airflow along the curved surface over the desired path is reliably achieved. In this embodiment the airflow is diverted when it hits the curved surface or directly before it hits the curved surface from an air duct generally running horizontally within the extractor hood. This diversion causes the airflow to be routed along the curved surface and premature tearing away of the airflow from the curved surface can be prevented.
In accordance with the invention an airflow is generated by the air outlet in conjunction with the adjoining curved surface which runs from the top of the extractor hood to the bottom of the extractor hood. The airflow generates an air curtain exiting from the bottom of the extractor hood around vapor which rises from a cooking zone located below the extractor hood. This enables the escape of the vapor to the side to be prevented.
The curved surface is inventively provided in order to guide the airflow exiting at the top of the extractor hood to the front side or bottom of the extractor hood, from which the airflow is directed in the form of an air curtain to a cooking zone arranged below the extractor hood or to an area surrounding the cooking zone. Guiding the airflow to the front side or bottom of the extractor hood in particular does not mean a direct introduction of the airflow into the extraction opening of the extractor hood. Instead the airflow separates itself from a curved surface and forms a curtain which essentially runs vertically downwards.
The fact that the air outlet is provided on the top of the extractor hood and the airflow extends in direction of the bottom and if necessary right down to the bottom of the extractor hood means that the length of the airflow on the curved surface is also increased. The increased length of the airflow on the surface of the curved surface means that the original volume flow required from the air outlet gap can be minimized to generate the air curtain which is emitted by the extractor hood.
In addition the air outlet gap provided on the top of the extractor hood is not visible to the user, which improves the visual appearance of the extractor hood. Also a duct routed around the curved surface which leads to an increased height of the extractor hood, at least in the region of the air outlet, especially in the edge region of the extractor hood, is not necessary in the present invention. The overall height of the extractor hood can thus be reduced. There is also no danger of the user of the extractor hood being irritated by an airflow exiting upwards from the top of the extractor hood which collides with a curved surface.
The air outlet gap is preferably provided on an air duct running from the fan of the extractor hood to a least one edge region of the extractor hood. This embodiment enables the air sucked in by the fan into the extractor hood and prepared, especially filtered, to be used to form the air curtain. A supplementary fan is not necessary in this case. In addition to the simpler layout, the inventive extractor hood has an additional advantage in this embodiment in that the noise generated which occurs when a supplementary fan is used, is absent. The use of prepared air to generate the air curtain is possible with the present invention since only a small volume flow is needed and the air used does not have a disadvantageous effect on the environmental conditions of the extractor hood. In particular the controlled household ventilation and thereby the heat requirement in the cooking environment is not affected by the air curtain. The air ducts can be connected directly to the fan or to the fan housing surrounding said fan respectively. Alternatively the duct can also be connected to an exhaust duct in which the air is transported away from the fan housing and thus direct part of the air extracted by the fan to the air outlet gap.
Preferably the curved surface which adjoins the air outlet is a lateral outer surface of the extractor hood, especially the outer edge of the extractor hood, especially a vapor shield of the extractor hood.
By using an outer surface of the extractor hood as the curved surface to route the airflow, the ambient air comes into contact with the curved surface on which the airflow is guided. This is of advantage since it means that more ambient air can be accepted into the airflow over a great length of the airflow as a result of the arrangement of the air outlet gap on the top of the extractor hood. This increases the mass flow to be emitted as an air curtain around or onto the cooking zone and increases the shielding effect of the vapor or of the direction of the vapor from the cooking zone to the extraction opening of the extractor hood.
In accordance with one embodiment in the inventive extractor hood and at least one control element for controlling the extractor hood is provided on the curved surface. This arrangement of the least one control element can be realized in the inventive embodiment of the extractor hood since on a front side of the extractor hood and especially of the vapor shield to which the control elements are generally attached, a rupture edge of an airflow directed over the curved surface can be intended or a least acceptable. From this position the airflow with ambient air as an air curtain can move on directed downwards. With an extractor hood in which a direct introduction of an airflow routed via the curved surface into the extraction opening of the extractor hood is intended, an arrangement of controls on the curved surface is not possible.
With the extractor hood the gap width of the air outlet gap is preferably set as a function of the radius of curvature of the curved surface. The ratio of the gap width and the radius of curvature of the curved surface enable on the one hand the spoiler of the airflow from the curved surface to be defined. This spoiler is preferably set at a position which is spaced away from the lowest point of the curved surface. This position faces away from the extraction opening of the extractor hood, so that a direct introduction of the generated airflow into the extraction opening of the extractor hood can be avoided. Furthermore the setting of the gap width of the air outlet gap as a function of the radius of curvature of the curved surface enables a vacuum arising out of the curved surface in the vicinity of the air outlet gap to be set. Using this vacuum, in addition to the pure pulling in of ambient air by the air stream routed on the curved surface, an additional sucking in of ambient air into the air stream is caused. This also greatly increases the mass flow forming the air curtain below the extractor hood or the volume of prepared air needed to generate the mass flow through the air outlet gap is reduced.
In accordance with one embodiment the extractor hood has an edge element, especially a tubular edge element which forms the curved surface on which the air flow from the air outlet gap is directed. By using an edge element which can be manufactured separately from the other components of the extractor hood it is possible to produce this edge element in the material required for optical or other purposes. By embodying the edge element as a tube, on the one hand this can reduce the overall weight of the extractor hood compared to using a full cylinder. On the other hand the edge element can be used to accept further components, such as for example illumination elements or the actuation devices for the controls mentioned above.
The air outlet gap is delimited in accordance with one embodiment by the curved surface and a cover of the top of the extractor hood, with the cover of the top of the extractor hood lying in a plane of the highest point of the curved surface or below the plane of the highest point of the curved surface.
In this embodiment the overall height of the extractor hood can be minimal in the edge area, especially in the edge area of the vapor shield or of the screen. The overall height in this case is defined exclusively by the radius of the curved surface. Especially in the embodiment in which the cover lies in the same plane as the highest point of the curved surface, the extractor hood can additionally give a uniform appearance, meaning that with a smaller overall height no protrusions are provided on the top of the extractor hood in the edge area.
In accordance with one embodiment the cover of the extractor hood, which forms the air outlet gap together with the curved surface, is the cover of a vapor shield or of the screen of an extractor hood respectively. Such a cover is provided for extractor hoods, especially with chimneys made of metal. By using this cover of the extractor hood to form the air outlet gap additional provision of further components on the extractor hood, especially the outside of the extractor hood, can be avoided.
In accordance with a further embodiment the extraction opening of the extractor hood is offset upwards in relation to the bottom of the curved surface. This arrangement on the one hand allows the airflow routed on the curved surface to easily avoid being sucked directly into the extraction opening. On the other hand the displacement of the extraction opening to the bottom of the hood allows an explicit feeding of rising vapor into the extraction opening to be realized. Preferably in this embodiment the lowest point of the curved surface is connected to the edge of the extraction opening arranged offset via a sheet of metal or a plate arranged at an angle. This enables the vapor guidance to the extraction opening to be further improved.
In accordance with a further embodiment the extractor hood has at least one side profile, of which the lower end lies in the same plane as the bottom of the curved surface. This embodiment enables the extractor hood to be given a uniform appearance. In addition the lateral delimitation of the space below the extraction opening can improve the feeding of vapor into the extraction opening. The lateral profile can be embodied as a sheet of metal or represent a further curved surface.
In accordance with an embodiment at least one baffle element is provided in the air guidance duct from the fan to the edge area at the air outlet gap. The baffle element serves specially to align the air in the air guidance duct so that the air leaving the air outlet gap is guided safely on the curved surface. By providing the baffle element in the air duct this element does not influence the external shape of the extractor hood and thereby its appearance and dimensions. The baffle element can in particular be provided at the output of the air guidance duct, meaning in the immediate vicinity of the air outlet gap.
The baffle element is especially preferably embodied so that this element reduces the cross-section of the air guidance duct at the exit of the air guidance duct. This enables formation of a flow of air to be guaranteed even with low flow speed in the air guidance duct. In addition the baffle element as well as the arrangement of the air outlet gap serves to direct a flow of air exiting from the air outlet gap in a direction which has a least one vertical direction component.
The inventive extractor hood can be a wall-mounted extractor hood, a wall chimney or an island chimney. Depending on the construction, air outlet gaps are provided at one or more edge regions. In a wall-mounted extractor hood, especially for building into or between upper kitchen cabinets, there is preferably provision for an air outlet gap on the front side of the extractor hood in the edge region. With a wall chimney an air outlet gap can be provided on the three free sides, i.e. on the sides on which the chimney is not attached to the wall, or even only on the front side of the wall chimney on the top. Finally, with an island chimney an air gap can be provided preferably at all four edge areas in the top of the extractor hood, especially the vapor shield of the extractor hood.
The invention will be explained once again with reference to the enclosed figures. The figures show:
In accordance with a first embodiment shown in
Provided on the bottom of the housing is a vapor shield or a screen 4. Via the interior 5 of the vapor shield 4 air sucked in can reach the fan 3 in the housing 2. In the bottom of the vapor shield 4 is an extraction opening. Fumes are directed via this extraction opening 7, in which a filter element 8 is provided in the embodiment shown, from below the extractor hood 1 into the interior 5 of the vapor shield 4 and up to the fan of the extractor hood 1.
An exhaust duct 9′ is provided on the fan 3 or on the fan housing or ventilator housing surrounding the actual fan 3, via which air which is sucked in from the fan 3, can be output for example via an exhaust duct to the outside. Furthermore the fan 3 is connected to air ducts which transport air from the fan 3 via the vapor shield through to the edge region 10 of the extractor hood 1, especially of the vapor shield 4. The air ducts 9 can be provided on the fan 3 or on its fan housing itself or on the exhaust duct 9′. The end of the air ducts which lies in the edge region 10 of the vapor shield, is formed by an air outlet gap 11. The air outlet gap 11 is arranged on the top 12 of the vapor shield or the screen 4. The air outlet gap 11 is delimited on the side facing the housing 2 by a sheet 13 essentially covering the top 12 of the vapor shield. The side of the air outlet gap 11 facing towards the edge of the vapor screen 4 is formed by the outer surface 14 or an essentially tubular edge element 15.
The structure of the air outlet gap 11 and or the edge region 10 of the extractor hood 1 is shown in a detailed schematic view in
As can be seen from
The prepared air transported via the air duct 9 to the air outlet gap 11 is let out of the extractor hood 1 through the air outlet gap 11. The air flow 16 in this case is directed upwards to the air outlet gap from the horizontal. The fact that the air flow 16 exiting from the air outlet gap 11 is directed to the outer surface 14 of the edge element 15 means that the air flow 16 is next to the outer surface 14. The air flow 16 remains on the outer surface 14 as a result of the so-called Coanda effect and is only released from the outer surface 14 at a spoiler 17. The spoiler 17 lies in the embodiment illustrated offset outwards to the center of the edge element 15.
From this spoiler 17 the air flow 16 forms an air curtain 18 as a result of the eddies formed. The air curtain 18 is directed at the spoiler 17 depicted in
The air curtain 18 is directed from the extractor hood 1 to the cooking zone located below the extractor hood 1 or into an area immediately around the cooking zone. As soon as the air curtain 18 reaches the cooking zone, this will heat up together with rising vapor and through this temperature change will promote the conveyance of the fumes to the extraction opening 7 of the extractor hood.
As can be seen from
The air guidance duct 19 or the air ducts respectively can be formed by incorporating a metal sheet 20 or another delimiting wall into the interior 5 of the vapor shield 4. Alternatively it is also possible to form the air ducts 9 or the air duct by a tubular construction.
The height of the central part 21 of the vapor shield 4 is less than the height of the edge element 15. In particular the suction opening 7 is offset upwards in relation to the lowest point 142 of the curved surface 14 formed by the edge element 15. The top of the center part 21 is offset downwards in relation to the highest point 141 of the curved surface 14. The transition between the central part 21 and the curved surface 14 is formed by angled pieces 22 and 23. The angled piece 22 which connects the lowest point 142 of the curved surface to the central part 21, especially in the vicinity of the suction opening 7, is used for guiding vapor to the suction opening. The duct 9 formed between the cover or the sheet 13 respectively and the top of the central part 21 is used for guiding air to the air outlet gap 11. In the area of the angled pieces 23 the height of the air duct 9 reduces.
The
The invention is not restricted to the embodiments shown. In particular, instead of the tubular edge element shown, an edge element can also be used for example which only features a section of the outer surface of a tube. For example a half-tube can be used. Furthermore edge elements can also be used which feature a cross-section differing from a circular cross-section. For example an oval tube or a section of an outer surface of an oval tube can be used.
The present invention makes an energy efficient, low-cost and low-noise extraction of fumes by means of an extractor hood possible. In addition the influence of the extractor hood on a controlled domestic ventilation and thereby on the heat requirement in the cooking environment is reduced by the low volume flow needed to generate the airflow. Finally the constructive outlay of the inventive extractor hood is low and the optical appearance of the extractor hood is improved as a result of the reduced dimensions of the vapor shield or of the screen which can be implemented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 013 319.9 | Mar 2007 | DE | national |
| 10 2007 039 635.1 | Aug 2007 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2008/052364 | 2/27/2008 | WO | 00 | 3/15/2010 |
