EP2581668A1

EP2581668A1 - Cooking unit

Info

Publication number: EP2581668A1
Application number: EP11008640.2A
Authority: EP
Inventors: Gianni Borinato; Giannino Piazza; Paolo Andriolo
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-10-10
Filing date: 2011-10-28
Publication date: 2013-04-17

Abstract

The invention relates to a cooking unit (4) with a heating surface (10) for warming up food. In the edge region (12) of the heating surface (10), means (32) are arranged, and above the heating surface (10), an extraction device (18) is arranged. With these means (32), a first air flow (30) and a second air flow (34), located at a distance (36) above the first air flow (30), are provided, the first air flow (30) or the second air flow (34), respectively, being sucked off by means of the extraction device (18). Alternatively, the means (32) provide a first air flow (30), whose air speed is less than 6 m/s and which is sucked off by means of the extraction device (18).

Description

The invention concerns a cooking unit with a heating surface for warming up food.
If food is prepared, for example cooked or grilled, by means of a cooking unit within closed rooms, odours will develop that people who stay inside the room find annoying. In particular the preparation of food by means of heated fat or the grilling of sea food produces such exhalations. Normally, extractor hoods are mounted over the cooking unit to suck off the air containing the odours and possible fat residues. This air is either cleaned or is passed to the outside of the room. Such extractor hoods are either relatively little effective or cause a relatively high noise disturbance.
Furthermore, there must be a time span between the starting up of the extractor hoods and the preparing of the food, so that an air flow can be generated for transporting any arising odours directly into the extractor hood. Therefore, spontaneous preparation of food is always accompanied by an undesired development of odours. If such a cooking unit is used in a restaurant where food is prepared at the guest's table, either the extractor hood must substantially operate continuously, which causes increased power requirements, or the guest has to wait for a disproportionately long time before the ordered food is prepared.
The invention is based on the problem to provide a particularly suitable cooking unit with a preferably relatively low noise development, avoiding in particular an odour nuisance to the users as reliably as possible.
This problem is solved according to the invention by the features of claims 1 or 4. Advantageous developments and embodiments are the subject matter of the dependent claims related thereto.
The cooking unit comprises a heating surface for warming up food, wherein the temperature of the heating surface may be increased to in particular more than 100°C. Conveniently, the food is laid down directly on the heating surface, it is, however, also possible to put the food in an additional container, such as a pot or a pan and to place this container on the heating surface. Alternatively, the container can also substantially form the heating surface.
In the edge region of the heating surface, means are arranged which are designed for providing a first and a second air flow. The means for providing the first air flow and the means for providing the second air flow can be arranged in separate housings or the like. Particularly preferably, the means are mounted within one single housing. The means for providing the second air flow are in particular located above the means for providing the first air flow, the second air flow being situated at least at a distance above the first air flow.
Expediently, the air flows are of a flat form. Advantageously, each air flow passes over the heating surface, shielding the latter in this way against the environment of the cooking unit. Between the air flows and the heating surface, a space is formed within which any odours or floating particles exhaled by the food are retained. If these particles approach the first air flow, they will be carried along and accelerated in the direction of movement of the air of the first air flow. Should, nevertheless, such a particle get through the first air flow, it will be carried off by the second air flow, so that practically no particle will penetrate the first and second air flows.
The first air flow or the second air flow is sucked off by means of an extraction device arranged above the heating surface. In particular, the particles possibly present are also absorbed by the extraction device. Suitably, both the first and the second air flow are sucked off by the extraction device. In this way, the cooking unit is of a space-saving design. To improve the efficiency of the cooking unit, the respective second air flow is directed towards the extraction device. In other words, the direction of movement of the air from the means to the extraction device is substantially straight-lined.
For example, the heating surface is rectangular and along one side of the rectangle, the means for providing the, or each, air flow are arranged. On the side of the heating surface opposite these means, the extraction device is located. In particular, the extraction device is mounted on a wall located there. Thus, the air flows, the heating surface, and the wall, viewed in cross-section, substantially form a triangle. It would, however, also be imaginable that the extraction device is mounted on a ceiling of a room in which the cooking unit is located.
With the cooking unit, it is possible to prepare inside a room even food producing great exhalations, such as, for example, fish or other seafood. Due to the separation of the heating surface from the environment, the environment is free of odour nuisance, while the food is, nevertheless, visible for persons. Furthermore, it is possible to treat the food while it is being warmed up, for example to spice it up or turn it. Due to the generation of the air flow with the help of the means for providing the, or each, air flow and the thus substantially immediate shielding of the heating surface, the food can be prepared substantially immediately after putting the cooking unit into operation, without odours escaping into the environment.
In addition to the first and second air flows, further air flows can be provided, in order to achieve, if needed, an even better shielding of the heating surface from the environment of the cooking unit.
The distance between the first air flow and the second air flow is, for example, between 1 cm and 10 cm and may vary along the two air flows. In this way, a relatively reliable shielding of the environment from cooking odours is guaranteed, the cooking unit having compact dimensions. Furthermore, the two air flows are separated, which reduces turbulences and mutual interferences of the air flows. The distance between the two air flows is in particular 2 cm.
Preferably, the distance between the first and second air flows is one fortieth of the diameter of the in particular circular heating surface, plus 10mm. For example, the distance will be 15 mm, if the diameter of the heating surface is 20 cm, 25 mm for a diameter of 60 cm, and 35 mm for a diameter of 100 cm.
Expediently, the first air flow and the second air flow include in the area of the means an angle of less than 20°. In particular, the air flows substantially extend flatly and the angle included by the two planes within each of which one of the air flows lies, is 20° or less. Suitably, the angle is less than 10° and the direction of spread of the two air flows is, for example, parallel. In other words, the two planes are parallel, it would, however, also be imaginable that the direction of spread of one of the air flows is substantially opposed to the other. It is particularly preferred that the two air flows are blown in the direction of the extraction device and provided at an angle which is smaller than 20°.
In an alternative embodiment, which can, however, also be combined with the above-mentioned embodiment, the cooking unit having a heating surface for warming up food included in the edge region of the heating surface means providing a first air flow. The first air flow is sucked off by means of an extraction device located above the heating surface. The extraction device can be arranged both centrically with, and offset against, the heating surface. At least, the heating surface and the food located, for example, thereon, are separated by means of the air flow from the environment of the cooking unit.
The speed at which the air of the first air flow moves, is lower than 6 m/s, the speed being preferably higher than 1 m/s. In this way, a relatively low noise generation of the cooking unit is guaranteed, with the environment of the cooking unit being, nevertheless, olfactorily shielded against the food.
In an expedient embodiment of the invention, the air speed of the first or second air flow is lower than 4 m/s and in particular lower than 3 m/s. Advantageously, the air speed is higher than 2 m/s. Particularly preferably, the air speed is 2.65 m/s. With this air speed, a reliable shielding of any arising odours is effectively possible, with the noise disturbance caused by the, or each, air flow due to turbulences or the like being low.
Advantageously, the thickness of the curtain-like first or second air flow is between 3 mm and 7 mm. By thickness, one understands here in particular the smallest extension of the air flow normal to its direction of spread. A thickness of 5 mm of the respective air flow is particularly suitable. Due to these dimensions, the cooking unit can be built in a relatively space-saving manner, with the shielding being, nevertheless, reliable.
Preferably, the air of the first or second air flow, sucked off by means of the extraction device, is returned to the means and used for a repeated creation of the air flow. The air is returned, for example, inside the cooking unit by means of tubes or hoses. Suitably, the extraction device is followed by an intake system connected directly or via another system to a fan, in such a way that the air is passed from the extraction device to the fan. In particular, the air is sucked in by means of the fan, and expediently, the fan generates an underpressure, by means of which the extraction device is operated. Preferably, the fan generates an overpressure on the side of the fan which is opposite the extraction device, said overpressure moving the air to the means and providing the respective air flow.
The fan is advantageously operated by means of an electric motor and comprises in particular a fan wheel having a diameter between 20 cm and 30 cm. For example, the diameter is 25 cm. The rotational speed of the fan wheel, during operation of the cooking unit, preferably lies between 800 rpm and 2800 rpm. This guarantees a low noise development of the fan. For further reducing the noise, the fan is, for example, sound-insulated by means of additional elements.
Suitably, the air between the extraction device and the means is cleaned by means of a filter system. The filter system is preferably located between the intake system and the fan, it can, however, also be mounted in another location. Preferably, the filter system is removable and includes, for example, a first filter and a second filter, the first filter being arranged in front of the second filter, viewed in the direction of movement of the air. The first filter is washable and serves for catching and retaining fat residues of the prepared food, which are in the air. The second filter is a carbon filter, by means of which odours and other residues are removed from the air. The washable first filter prevents a pollution of the carbon filter caused by the fat residues and increases the operating time of the filter system.
By means of the extraction device, the intake and filter systems, the fan, and the means for providing the, or each, air flow, a substantially closed system is realized. Between the extraction device and the means for providing the, or each, air flow, further elements can be arranged. The order of the elements located between them may also vary. The substantially closed system enables an integration of the cooking unit into existing kitchens, dining rooms or the like, without having to change the construction of the rooms to guarantee a supply of the cooking unit with fresh air for the air flow(s). Furthermore, additional intake systems and blowoff systems can be provided, so that a certain share of the first or second air flow consists of fresh air continually taken from the environment, with the same share of used air being liberated into the environment.
Advantageously, the intake system has the shape of a hollow cylinder, the air being guided inside the intake system. For example, the intake system is a flexible hose or a tube. The inner diameter of the hollow cylinder lies between 7 cm and 10 cm. Particularly preferably, the inner diameter is 8.4 cm. In this way, a sufficiently large air flow rate through the intake system can be realized, without the air speed being relatively high. This will advantageously reduce the noise development. In addition, the space required by the intake system will be low.
The intake system suitably includes a number of tubes aligned in parallel to each other, which are in particular arranged inside the hollow-cylinder shape of the intake system or which substantially form the intake system. The division of the intake system into a multitude of tubes avoids turbulences inside the sucked-off air, which advantageously reduces the noise disturbance. For this purpose, the tubes are relatively long and have a relatively small diameter. In particular, the intake system comprises at least ten such tubes, which have a diameter in particular between 1 cm and 3 cm. The length of the tubes lies during operation of the cooking unit between 10 cm and 30 cm.
In a preferred embodiment of the invention, the heating surface is of a circular shape and has in particular a diameter between 30 cm and 50 cm, a diameter of substantially 40 cm being particularly suitable. In this way, a surface for the preparation of food is provided, which is sufficiently large for all practical purposes, and the warming-up of the heating surface requires relatively little energy. Furthermore, these dimensions assure a manageable handling of the cooking unit.
Alternatively or in combination herewith, the heating surface comprises in particular a number von partial heating surfaces, expediently two or three partial heating surfaces, and is in particular composed of these. Each partial heating surface can separately be removed from the cooking unit. Thus, the cooking unit can be both disassembled and assembled in a relatively simple manner, and individual partial heating surfaces can be removed for being cleaned. Suitably, each partial heating surface has the shape of a segment of a circle.
Preferably, the heating surface is heated by means of an induction device. For this purpose, the heating surface is made of a magnetic material or at least contains such material. In particular, the heating surface consists of iron or has a core containing iron. Suitably below the heating surface, a current-carrying coil is arranged, by means of which a magnetic alternating field is generated. This magnetic field in turn induces eddy currents in the heating surface, which heat up the heating surface. This in turn warms up the food for its preparation. The induction device makes it possible to specifically warm up the food to a certain temperature, in particular to up to 250°C, with a relatively low power requirement.
Instead of the induction device, the heating surface could be heated by an electric resistor. The electric resistor, having a relatively high resistance value, is in thermal contact with the heating surface and is arranged in particular below said heating surface, for example in a meander, spiral or circular shape. Expediently, the longitudinal extension of the resistor is relatively great. If a relatively high electric voltage is applied on the electric resistor, the latter will warm up. Due to the thermal coupling with the heating surface, the heating surface is heated up. In this way, in particular temperatures of the heating surface of up to 500°C can be realized, the power consumption of the electric resistor lying between 1 kW and 2 kW. It would, however, also be imaginable that the heating surface has the shape of a grate and is heated by means of coals or gas flames arranged therebelow.
Expediently, the means for providing the first or second air flow are designed in the manner of nozzles. In other words, the respective air flow is directed by the preferably nozzle-like means in the direction of the extraction device. For this purpose, the means have in particular an outlet opening and an inlet opening, the air escaping through the outlet opening towards the air flow and the air being guided to the means through the inlet opening. In particular, the inlet opening is pneumatically connected with the fan. Expediently, the outlet opening is smaller than the inlet opening, which leads to an increased air speed of the respective air flow.
In a particularly preferred embodiment of the invention, the means for providing the, or each, air flow surround the edge of the heating surface substantially completely. The means for providing the, or each, air flow are immediately adjacent to the edge of the heating surface or are located at a distance from the edge of the heating surface. The outlet openings of the means are, for example, hole-shaped and distributed along the edge of the heating surface. Advantageously, however, the outlet opening of the means has the shape of a slot and surrounds the heating surface substantially in a ring-shaped manner. The width of the slot, corresponding in particular to the thickness of the air flow provided by means of this slot, lies, for example, between 4 mm and 6 mm. Preferably, two such slots are arranged one above the other, and the first air flow is provided by means of one of the slots and the second air flow is provided by means of the other slot.
Advantageously, the cooking unit comprises a device, in the following referred to as tower, which projects from the plane of the heating surface and is arranged in the middle of the heating surface. For example, the in particular round heating surface has a central recess, the tower being located in the recess. The longitudinal direction of the tower suitably extends substantially normal to the heating surface. The extraction device is attached to the tower, part of the tower expediently forming the extraction device. Preferably, the extraction device includes a slot-shaped inlet opening, through which the first or the second air flow are sucked off into the tower. The inlet opening surrounds the upper area of the tower, for example, in a ring-shaped manner.
In a preferred embodiment, the tower is designed in a rotationally hyperbolic shape, the tower being advantageously formed by the upper area of the hyperboloid shape. Thus, the diameter of the tower increases with increasing distance from the heating surface. In other words, the tower has substantially the shape of a scaled-down, upside down cooling tower of a power plant. Due to the fact that the cross-section of the tower is larger at a distance from the heating surface than in the cross-sectional area close to the heating surface, the tower projects over the heating surface. In this way, it is possible to suck off the first or second air flow simply and completely by means of the extraction device installed there, having, nevertheless, a relatively large surface available for preparing the food.
Furthermore, transport of the cooking unit is in this way facilitated, because the extraction device does not have to be mounted separately. Likewise, if the cooking unit is attached to, or integrated in, a table, a shifting of the table will not impair the functioning of the cooking unit, because the position of the extraction device relative to the heating surface will remain substantially constant. Furthermore, installation and functions of the cooking unit are practically independent of a ceiling height of the room in which the cooking unit is located.
Advantageously, the distance of the extraction device from the heating surface can be changed. Thus, the cooking unit can be adapted, for example, to the circumstances prevailing at the moment, such as any wind blowing, when the cooking unit is used outdoors. Expediently, for that purpose, the tower, to which the extraction device is attached, can be changed or shifted along its longitudinal extension. Preferably, the tower can be telescoped and in particular, the upper area of the tower can be put into contact with the heating surface or at least approached to it relatively closely. In this way, a space-saving storage of the cooking unit is assured. Furthermore, it is possible, in telescoped state, to place objects on the surface of the upper area of the tower, which is preferably plane and expediently flush with the environment of the cooking unit.
Preferably, a table grill is equipped with such a cooking unit, said table grill being in particular portable. By table grill, one understands here a grill which can be put on a dining table and can be removed after use. For this purpose, it is particularly preferred to guide the sucked-off air of the air flow inside the table grill to the nozzles again, so that the table grill has no other fan openings than the means for providing the, or each air flow, or the extraction device. Thus, the air is guided within a closed circulation. For putting the unit into operation, it is, therefore, expediently, only necessary to supply the cooking unit and/or the means providing the, or each air flow with electric power, which enables a fast installation and removal of the table grill. It is, in particular, not necessary to connect the table grill to an external, additional pneumatic system. In a gastronomic enterprise, a plurality of such table grills can be used.
For olfactory shielding of a first zone from a second zone, two air flows are used. The two air flows are situated in the area between the two zones. In particular, in each case, one of the air flows suitably completely limits one of the zones. Thus, between the two air flows, a border area is formed, extending between the first and second zones. Therefore, to get from the first zone into the second zone, the two air flows and the border area have to be passed. Advantageously, the two air flows are designed like a curtain or a wall. The direction of movement of the air inside the two air flows is parallel and their respective speeds are, for example, identical. Advantageously, the distance between the two air flows lies between 1 cm and 10 cm.
In addition to the two air flows, additional air flows can be used, which are substantially parallel to the first two air flows and are also situated between the two zones. In this way, the efficiency of the olfactory shielding is increased.
In the following, an exemplary embodiment of the invention is explained in detail by means of a drawing, in which

Fig. 1: is a perspective view of a table grill with a cooking unit,
Fig. 2: is a sectional view of a tower of the cooking unit,
Fig. 3: is a bottom view of the tower,
Fig. 4: is a sectional view of the cooking unit in operation,
Fig. 5: shows the cooking unit of Fig. 5 with an alternative embodiment of the tower,
Fig. 6: is an enlarged view of a detail of the cooking unit of Fig. 5, and
Fig. 7: shows the cooking unit of Fig. 5, put out of operation.

Parts corresponding to each other are marked with the same reference number in all figures.
Fig. 1 is a perspective view of a table grill 2 with a cooking unit 4. The table grill 2 is portable and can be shifted or rearranged inside a room of a gastronomic enterprise. The cooking unit 4 is substantially embedded in a round recess of a table top 6, with a peripheral ridge 8 limiting the cooking unit 4 on its periphery and resting on the table top 6. Inside the peripheral ridge 8 and in contact therewith, a round heating surface 10 is arranged, which is parallel to the surface of the table top 6. The edge region 12 of the heating surface 10 is completely surrounded by the peripheral ridge 8. The heating surface 10 is lowered relative to the surface of the table top 6. The diameter of the heating surface 10 is 40 cm.
The centrically recessed heating surface 10 comprises a first partial heating surface 10a and a second partial heating surface 10b, each of which has the shape of a segment of a circle. Each partial heating surface 10a, 10b can separately be removed from the edge formed by the peripheral ridge 8 and from the table top 6, for example for cleaning the partial heating surface10a, 10b. Inside the recess of the heating surface 10, a tower 14 is arranged. The tower 14 is in part designed in a rotationally hyperbolic shape, the diameter of the tower 14 increasing with increasing distance from the heating surface 10. The tower 14 includes a lid 16, which forms the upper end of the tower 14 and is parallel both to the heating surface 10 and to the table top 6.
Fig. 2 and Fig. 3 are a sectional view and a bottom view, respectively, of the tower 14 of the cooking unit 4. To the tower 14, an extraction device 18 is attached, which includes a first extraction slot 18a and a second extraction slot 18b. The two extraction slots 18a, 18b arranged in the upper third of the tower 14 extend completely along the periphery of the tower 14 and are parallel to the lid 16. Inside the tower 14, an intake device 20 is arranged, substantially extending vertically and parallelly to the longitudinal direction of the tower 14, i.e. normal to the lid 16. In the area of the intake device 20, the diameter of the tower 14 is substantially constant and amounts to 8.4 cm. Above the intake device 29, the tower 14 is designed in the shape of a funnel. The intake device 20 includes a number of tubes 22 extending in parallel to each other and to the longitudinal direction of the tower 14. The tubes 22 completely fill the inside of the tower 14 in the area of the intake device 20. Each of these tubes 22 has the shape of a hollow cylinder and has an inner diameter of 2 cm.
The operation of the cooking unit 4 is schematically illustrated in Fig. 4 in a sectional view, with the heating surface 10 of the cooking unit 4, contrary to the illustration of Fig. 1, just being placed on the table top 6 and not embedded into the latter. The heating surface 10 is heated up by means of an electric coil 24 arranged therebelow, which is part of an induction device 26. The induction device 26 also comprises electronics (not shown) and a convertor and serves for generating a magnetic alternating field. This magnetic alternating field induces in the magnetic heating surface 10 induction currents, which heat up the heating surface 10.
Oil, food, or the like, present on the heated-up heating surface 10, generates odours 28. These rise upwards, due to their being warmed up by the heating surface 10, until they hit a first air flow 30 provided by nozzle-like means 32 located inside the peripheral ridge 8. The odours 28 are carried along by the first air flow and accelerated in the direction of the tower 14. There, the odours 28 are sucked off with the air of the first air flow 30 through the extraction slot 18a of the extraction device 18. Should odours 28 get through the first air flow 30 and continue rising upwards, these will be carried along by a second air flow 34, located at a distance 36 above the first air flow 30. The distance 36 between the two air flows 30, 34 is 2 cm. The distance 36 between the two air flows 30, 34 is larger in the vicinity of the tower 14 than in the vicinity of the means 32. In other words, the two air flows 30, 34 are not parallel to each other, but include an angle of substantially 10°. The speed at which the air of the two air flows 30, 24 moves, is 2.7 m/s.
The air 37 sucked off by means of the extraction device 18 is passed inside the tower 14 through the tubes 22 of the intake device 20 to a filter system 38. The tubes 22 prevent whirls in the air 37. First of all, any fat particles present in the sucked-off air 37 are removed from the air 37 by means of a washable first filter 38a. The first filter 38a is followed by a second filter 38b, which is a carbon filter. By means of the latter, further residues are removed from the air 37, so that there are no odours 28 in the air 37 coming out of the filter system 38. The fact that the fat residues are removed from the air 37 before the air 37 is introduced into the carbon filter 38b clearly increases the lifetime of the carbon filter 38b. Since the first filter 38a is washable, it can also be used for a relatively long period of time. The first filter 38a just has to be taken out of the cooking unit 4 and cleaned at regular intervals.
Downstream of the filter system 38, a fan 40 is pneumatically switched, by means of which an underpressure is generated, sucking in the air 37 through the intake system 20 and the filter system 38. For this purpose, the fan 40 comprises a fan wheel 40a, moved by means of an electric motor 40b. The diameter of the fan wheel 40a is 25 cm, and the rotational speed, realized by means of the electric motor 40b, of the fan wheel 40a lies between 800 rpm and 2800 rpm. For suppressing operating noises, the fan 40 is surrounded by an additional sound insulation (not shown here) and includes a suitable anti-vibration suspension.
On the side of the fan 40 which is pneumatically opposite the filter system 38, the latter generates an overpressure. This overpressure moves the air, which is present on this side of the fan 40 and which has been cleaned before by means of the filter system 38, away from the fan 40. By means of an air guiding system 42, the air is again passed to the means 32, a lower nozzle 32a providing the first air flow 30 and an upper nozzle 32b, the second air flow 34. The two nozzles 32a, 32b are substantially slot-shaped and arranged along the entire inner circumference of the peripheral ridge 8, vertically spaced from each other by 2 cm. The width of the slot of each of the nozzles 32a, 32b is 5 mm. Thus, the first air flow 30 and the second air flow 34 also have a thickness of 5 mm in the area of the means 32.
The cross-section of the slot-shaped outlet openings of the two nozzles 32a, 32b is smaller than the cross-section of the air guiding system 42. Therefore, to assure that the speed of the air flows 30, 34 is equal to 2.7 m/s, a lower air speed is necessary inside the air guiding system 42. Therefore, relatively little whirls arise inside the air guiding system 42, so that the air is moved practically noiselessly inside the air guiding system 42. Furthermore, due to the relatively low air speed inside the air guiding system 42, the fan 40 can be operated at a relatively low rotational speed, which also reduces the noise level emitted by the cooking unit 4.
Due to the design of the nozzles 32a, 32b, the respective air flows 30, 42 completely cover the heating surface 10 in the manner of a shell and cover a first zone 44 located between the heating surface 10 and the first air flow 30. Said first zone 44 is olfactorily separated from the environment of the cooking unit 2, constituting a second zone 46, by means of the first and second air flows 30, 34. In other words, no odours 28 will get from the first zone 44 into the second zone 46. The noise development of the cooking unit 4 is less than 50 db at a distance of 1 m from the cooking unit 4.
The cooking unit 4 can also be operated by means of the first air flow 30 or the second air flow 34 only. To achieve, nevertheless, a sufficient shielding of the first zone 44 from the second zone 46, the air speed of the respective air flow 30, 34 can be increased, always staying substantially below 6 m/s. In this way, the persons present will not be bothered neither by smell nor by noise through the cooking unit 4.
Fig. 5 shows an alternative embodiment of the cooking unit 4. Contrary to the embodiment shown in Fig. 4, the heating surface 10 is heated in this case by means of an electric resistor 48. The electric resistor 48 will be heated up, if an electric voltage is applied on it, with a thermal coupling transferring this heat to the heating surface 10. To achieve as energy-efficient a temperature transfer as possible, the electric resistor 48 is arranged, in the form of meanders or spirals, below, and substantially all over, the heating surface 10. The electric resistor 48 is in mechanical contact with the heating surface 10, either via heat-conducting means, such as a conventional heat-conducting paste, or directly. As compared with the induction device 24, higher temperatures of the heating surface 10 can be realized with the electric resistor 48. On the other hand, the energy efficiency of the induction device 24 is relatively high.
Furthermore, the diameter of the lid 16 of the tower 14 and the diameter of the upper area of the tower are increased as compared with the cooking unit 4 shown in Fig. 1 to Fig. 4. The dimension of the lid 16 is substantially the same as that of the heating surface 10. In other words, the diameter of the lid 16 is substantially 40 cm. The diameter of the extraction slots 18a, 18b is also increased, and therefore, the distance of the extraction slots 18a, 18b from the means 32 is reduced. Thus, the shielding of the first zone 44 from the second zone 46 is further improved, because the border area between the two zones 44, 46 and the extension of the two air flows 30, 34 in the direction of their respective direction of movement is relatively small.
To make sure that the air flows 30, 34 hit the respective extraction slots 18a, 18b substantially in a rectilinear manner, said air flows include with the heating surface 10 a larger angle, as compared with the embodiment shown in Fig. 4. The angle between the second air flow 34 and the heating surface is larger than 45°. As is evident from Fig. 6, the angle between the two air flows 30, 34 is also increased.
Fig. 7 shows the cooking unit 4 with the tower 14 in a telescoped state. For this purpose, the tower 14 is of a telescopic design, with the area of the tower 14 in which the intake device 20 is mounted remaining unmoved. The funnel-shaped part of the tower 14, which during operation of the cooking unit 4 is adjacent to, and above, that area, is lowered and takes up the unmoved area of the tower 14. In this way, it is possible to make the lid 16 flush with the peripheral ridge 8. In other words, the lid 16 and the peripheral ridge 8 form together a substantially plane surface, which can be used for placing objects thereon. Furthermore, this assures a space-saving storage of the cooking unit 4.
As the upper part of the tower 14 can be shifted relative to the lower area of the tower 14, the extraction slots 18a, 18b can also be shifted relative to the heating surface 10. This changes the distance of the extraction slots 18a, 18b from the heating surface 10. If, for example, the table grill 2 is used outdoors, it will be possible to adapt the extension of the air flows 30, 34, i.e. to reduce them, such that an effective shielding of the first zone 44 from the second zone 46 is given even at relatively high wind speeds. For this purpose, the orientation of the two nozzles 32a, 32b is suitably also changed such that the air flows 30, 34 hit the respective extraction slots 18a, 18b. The angle between the two air flows 30, 34 and the heating surface 10 is thus reduced.
The invention is not limited to the above-described exemplary embodiment. Rather can the person skilled in the art derive therefrom other variants of the invention, without leaving the subject matter of the invention. In particular, furthermore, all individual features described in connection with the exemplary embodiment can also be combined in another manner, without leaving the subject matter of the invention.

Bezugszeichenliste

2: Table grill
4: Cooking unit
6: Table top
8: Peripheral ridge
10: Heating surface
10a: Partial heating surface
10b: Partial heating surface
12: Edge region
14: Tower
16: Lid
18: Extraction device
18a: Extraction slot
18b: Extraction slot
20: Intake device
22: Tube
24: Electric coil
26: Induction device
28: Odours
30: First air flow
32: Means
32a: Lower nozzle
32b: Upper nozzle
34: Second air flow
36: Distance
37: Sucked-off air
38: Filter system
38a: Lower nozzle
38b: Upper nozzle
40: Fan
40a: Fan wheel
40b: Motor
42: Air guiding system
44: First zone
46: Second zone
48: Electric resistor

Claims

A cooking unit (4)
- with a heating surface (10) for warming up food,

- with means (32), arranged in the edge region (12) of the heating surface (10),
for providing a first air flow (30) and a second air flow (34) at a distance (36) above the first air flow (30), and

- with an extraction device (18), arranged above the heating surface (10), for sucking off the first air flow (30) or the second air flow (34), respectively.
The cooking unit (4) of claim 1,
characterized in that
- the distance (36) between the first air flow (30) and the second air flow (34) is
more than 1 cm and less than 10 cm and in particular equal to 2 cm, and/or

- that the distance (36) is substantially calculated pursuant to D/40 + 10 mm, with D corresponding to the diameter of the heating surface (10).
The cooking unit (4) of claim 1 or 2,
characterized in that
the angle between the first air flow (30) and the second air flow (34) is less than 20° and in particular less than 10° in the area of the means (32).
A cooking unit (4)
- with a heating surface (10) for warming up food,

- with means (32), arranged in the edge region (12) of the heating surface (10), for providing a first air flow (30),

- with an extraction device (18), arranged above the heating surface (10), for sucking off the first air flow (30),
whereby the air speed of the first air flow (30) is less than 6 m/s.
The cooking unit (4) of any of claims 1 to 4,
characterized in that
- the air speed of the first air flow (30) or of the second air flow (34), respectively,
is less than 3 m/s and in particular less than 2.7 m/s and/or greater than 2 m/s,
and/or

- that the first air flow (30) or the second air flow (34), respectively, has a thickness
which is between 3 mm and 7 mm and in particular 5 mm.
The cooking unit (4) of any of claims 1 to 5,
characterized in that
the air (37) sucked off by the extraction device (18) is passed to the means (32) via an intake system (20) and via a filter system (38) as well as via a fan (40).
The cooking unit (4) of any of claims 1 to 6,
characterized in that
- the intake system (20) has a diameter between 7 cm and 10 cm and in particular
of 8.4 cm, and/or

- the intake system (20) comprises a number of tubes (22), aligned substantially
parallel to each other, through which the sucked-off air (37) is passed.
The cooking unit (4) of any of claims 1 to 7,
characterized in that
- the heating surface (10) has a diameter which is between 30 cm and 50 cm and in particular equal to 40 cm, and/or

- the heating surface (10) comprises at least two partial heating surfaces (10a, 10b).
The cooking unit (4) of any of claims 1 to 8,
characterized in that
the heating surface (10) is heated by means of an induction device (26) or an electric resistor (48).
The cooking unit (4) of any of claims 1 to 9,
characterized in that
the means (32) are shaped like nozzles and surround the heating surface (10) at its edge substantially completely.
The cooking unit (4) of any of claims 1 to 10,
characterized by
a tower (14), which is arranged substantially in the middle of the heating surface (10) and on which the extraction device (18) is mounted.
The cooking unit (4) of any of claims 1 to 11,
characterized in that,
by means of the tower (14), the extraction device (18) is movable towards the heating surface (10).
A portable table grill (2) with a cooking unit (4) of any of claims 1 to 12.
The portable table grill (2) of claim 13,
characterized in that
the air (37) for providing the first air flow (30) or the second air flow (34), respectively, is guided in a closed circulation.
Use of two air flows (30, 34), located next to each other and located between two zones (44, 46) for olfactory shielding of a first zone (44) from the second zone (46).