EP3620721B1 - Device for conduit extraction of exhaust air generated on a cooking hob - Google Patents

Description

The present invention relates to a device for trough suction of exhaust air generated on a hob.

Hollow hoods, ie fume hoods, which are used to extract exhaust air generated on a hob in a direction pointing vertically below the hob level, are known in the prior art. The features of the generic term are from the WO 2017/029128 A1 known. Further relevant prior art can be found in the documents WO 2018/036799 A1 , EP 3 133 350 A1 , U.S. 2,674,991 A , EP 2 581 668 A1 and DE 20 2007 018342 U1 known.

Compared to cooker hoods, i.e. Extractor hoods that are arranged on a room wall or a ceiling wall, however, have to provide hood hoods with a significantly higher extraction capacity. In order to avoid noise nuisance as a result of a high rotational frequency of the fan, but still ensure the required suction power, hollow hoods are therefore usually designed with two fans. As in extractor hoods, a fat separator unit is also provided in downdraft hoods, with which, if possible, it should be prevented that fat particles carried along in the exhaust air penetrate into the fan. However, the installation space available is limited in the case of fume cupboards because it is important to maintain the usability of base cabinets under the fume cupboard to the greatest possible extent. In trough hoods, a central area of the available installation space is therefore taken up by the grease trap unit, with the result that installation space for the usual two fans is only available next to the grease trap unit. A significant disadvantage associated with this is the loss of efficiency. This is because the exhaust air flow emerging from the grease separation unit has to be divided into two partial flows, which have to be sharply diverted several times and brought together again downstream of the fans. Another disadvantage relates to the manufacturing costs associated with the two fans required.

The present invention is based on the object of providing a trough hood which overcomes the disadvantages inherent in the prior art.

According to the invention, the object is achieved by a trough hood with the features of claim 1.

The fact that, according to the invention, the exhaust air flow emerging from the grease trap cartridge is fed to the impeller blades of the radial fan in a radially symmetrical manner and evenly distributed over 360 ° by means of the two-part guide device that communicates directly with it, avoids the loss of efficiency which, according to the prior art, results from the division of the air flowing out of the grease trap unit Exhaust air flow into two partial flows, which result in multiple sharp deflections and finally merging. By virtue of the inventive design and arrangement of the fat separating device and the two-part guide device, the impeller can also be designed in a size that allows a rotational frequency that does not cause any noise, but nevertheless provides the required suction power. The installation space required for the recessed vent according to the claims does not differ in terms of the installation width, which is determined by the spiral fan housing, from that which is required according to the aforementioned prior art. In contrast to the latter, the inventive trough extraction allows the installation height to be minimized in an advantageous manner by virtue of the grease trap cartridge partially integrated in the fan housing and the two-part guide device fully integrated therein.

Preferred embodiments as well as details and advantages of the present invention emerge from the subclaims.

Preferably, the impeller of the radial fan has a diameter which lies in a range from 400 to 440 mm, and the impeller blades are curved backwards with respect to a direction of rotation of the impeller. It can be seen that the radial fan of the downdraft extractor according to the claims not only securely provides the required suction power, it is also at least as quiet as the commercial radial fans installed in the aforementioned prior art, whose maximum diameter is 200 mm. Due to their backward curvature in relation to the direction of rotation of the impeller, the impeller blades are adapted to the flow profile of the sucked in exhaust air and thus have a higher degree of efficiency than the usual and forward-curved impeller blades in relation to the direction of rotation of the impeller.

In order to optimize the radially symmetrical and over 360 ° uniformly distributed flow course of the exhaust air flow acting on the impeller blades, the number of second flow lamellae exceeds that of the first flow lamella several times; this multiple is preferably in a range from 6 to 15.

For reasons of flow technology and acoustics, the annulus of a spiral fan housing has to increase steadily. For this purpose, the outer radius of the ceiling wall of the fan housing is usually increased continuously while the inner radius remains the same. The disadvantage here is that the installation width of the fan housing increases accordingly and thus requires a corresponding installation space. In order to avoid this disadvantage, according to a preferred embodiment of the present invention, the flow cross-section of the annular space is steadily increased in that the top wall of the fan housing has a reduced inner radius and the outer wall of the fan housing has an increased height in an area of the annular space while the outer radius remains unchanged.

When flowing through the flow lamellae of the flow grid ring of the second guide device, air turbulence inevitably occurs. In order to nevertheless achieve that the impeller blades are subjected to approximately laminar exhaust air flows without any loss of efficiency, the flow grid ring preferably has an outer radius that is 15 to 25 mm smaller than a radius R _i , which determines an inner circular path and on which the in direction of the flow grid ring facing ends of the impeller blades move during operation of the trough vent according to the invention.

According to a preferred embodiment of the inventive trough hood, the exhaust air conveyor channel formed by the fat separator cartridge is box-shaped and has two first and two second opposing side walls and the first guide unit is connected to circumferential lower edges of these side walls. The cross section of the air conveying channel is preferably rectangular or square. Furthermore, the circular base of the second guide unit has a trough-like area within which the base structure of the first guide device is arranged. This trough-like area ensures in an advantageous manner that separated grease droplets that collect in the floor structure of the first guide unit cannot get onto the impeller blades of the radial fan.

According to a preferred embodiment of the first fat separating device, which is arranged in the preferably box-shaped exhaust air conveyor channel, the exhaust air conveyor channel has two exhaust air conveyor channel halves in relation to a plane E _A containing its vertical central axis M _A , in which the first fat separating apparatus is a pair of first in each case mirror-symmetrical to this central plane E _A Having air guiding devices, a pair of second air guiding devices and a pair of third air guiding devices. The respective air guiding devices are each arranged mirror-symmetrically with respect to a plane E _AH containing a vertical center axis M _{AH of} the conveyor channel halves, namely in such a way that a first air guiding device is each supported by the Level E _{AH of} the exhaust air conveying channel half is arranged at a distance from the exhaust air inlet opening and is set up to direct an exhaust air flow entering through the exhaust air inlet opening in the direction of a second air guiding device, the second air guiding device in each case spaced from the first air guiding device and arranged along a section of the aforementioned level E _AH is and is set up to separate fat particles from the exhaust air flow and direct the exhaust air flow in the direction of a respective third air guide device, and the respective third air guide device is spaced from the respective second air guide device and from the aforementioned level E _AH and is set up to separate fat particles from the exhaust air flow and to steer in the direction of the second fat separator.

The fact that a pair of first, second and third air guide devices is provided in each half of the exhaust air conveying channel means that the exhaust air flow is deflected twice in succession in the area of the second and third air guiding devices in each half of each half of the exhaust air conveying channel and, as a result, the exhaust air flow is swirled in these areas. As a result of the turbulence, small fat particles carried along in the exhaust air flow conglomerate. Due to their mass, the conglomerated fat particles can no longer follow the streamlines of the deflected exhaust air flow, but adhere to the respective second and third air ducting devices, i.e. there they are separated from the exhaust air flow. In this way, a high degree of fat particle separation is achieved and the second fat separation device, which is connected downstream of the first fat separation device, is supplied with a highly pre-cleaned exhaust air stream.

Of the pairs of first, second and third air guiding devices provided in each exhaust air conveying channel half of the exhaust air conveying channel, each pair of the first air guiding devices and each pair of the third air guiding devices has a first first air guiding device and a respective first third air guiding device, which are preferably each integral with an inner surface of the two first opposite side walls of the fat separator cartridge are formed in such a way that the first air guide devices each protrude nose-like and the first third air guide devices each protrude like a shell into the respective exhaust air conveying channel half. Instead of nose-like, the first air guiding device in each case can also be convex and the term shell-like is to be understood as meaning that the first third air guiding device in each case has a sufficiently inwardly curved surface that allows the separated fat particles to be held.

Each pair of the first and third air guiding devices also has a second first air guiding device and a second third air guiding device, which are preferably provided by a first module that can be inserted into the exhaust air duct and releasably attached to the two second opposite side walls of the fat separation cartridge. This has the advantage that the air guiding devices provided by the first module - for example for cleaning purposes - can be easily removed from the grease separation cartridge.

The first module is preferably designed in the form of an anchor and, in relation to the center plane E _{A of} the exhaust air conveyor duct, has a mirror-symmetrical anchor head, a mirror-symmetrical, slim anchor neck and two mirror-symmetrical anchor arms.

The anchor head preferably has a diamond-shaped cross section, so that its head halves each protrude into the respective half of the respective exhaust air conveyor channel half. The mirror-symmetrical head halves of the anchor head can also be designed in an alternative form to this, which - such as a convex head half for example - is suitable for directing the inflowing exhaust air flow in the direction of the respective second air guiding device. The mirror-symmetrical, slim armature neck advantageously supports the guidance of the exhaust air flow directed towards a second, third air-guiding device, which is provided by the mirror-symmetrical armature arms that protrude into the respective exhaust air delivery channel half like a shell. Here, too, the term shell-like is to be understood to the effect that the anchor arms each have a sufficiently inwardly curved surface that allows separated fat particles to be held.

Each pair of the second air guiding devices is preferably provided by a second module which can be inserted in the respective exhaust air conveying channel half and is detachably fastened to the two second opposite side walls of the fat separating cartridge. This has the advantage that the air guiding devices provided by the respective second module - for example for cleaning purposes - can be easily removed from the fat separating cartridge.

The second module is preferably designed in the form of an anchor and has, in relation to the plane E _{AH of} the respective exhaust air conveyor half, a mirror-symmetrical, slim anchor neck and, in relation to the plane E _AH , two mirror-symmetrical anchor arms, each pointing away from the plane E _{AH in} a shell-like manner . The respective slim, mirror-symmetrical anchor neck is advantageous in that it guides the of the respective first half in each conveyor channel half or second first air guiding device in the direction of the respective second air guiding device assisted exhaust air flow. Here, too, the term shell-like is to be understood to the effect that the anchor arms each have a sufficiently inwardly curved surface that allows the separated fat particles to be held.

The second module in each case preferably has an anchor body which carries the anchor arms and which is designed to be mirror-symmetrical with respect to the respective plane E _AH . The anchor body is preferably hollow and is formed by two anchor body surfaces which combine in the respective plane E _AH and are each arranged at an acute angle to the respective plane E _AH . The design of the anchor body as a hollow body is advantageous in that it reduces the weight of the modules, which in turn is advantageous when removing the modules from the fat separation cartridge - for example for cleaning purposes. The respective acute-angled arrangement of the anchor body surfaces is advantageous insofar as the anchor body surfaces of the respective module support the guidance of the exhaust air flow directed by the respective second air guide device in the direction of the respective third air guide device in an advantageous manner. The respective acute angle is preferably in a range between 30 ° and 35 °.

In order to remove the last fat particles carried along in the exhaust air stream from the exhaust air stream pre-cleaned by the first fat separating device before it enters the first guide unit of the two-part guiding device, the second fat separating device is arranged below the third air ducting devices of the first fat separating device. The second fat separating device preferably has at least two perforated plates which are spaced apart from one another and which are each designed like a shell and are rotationally symmetrical to the central axis M _{A of} the exhaust air conveying channel.

In order to increase the efficiency of the second fat separating device, the at least two perforated plates have different diameters, which are selected so that the exhaust air flow partially flows around and partially flows through the at least two perforated plates. The diameters advantageously differ in a ratio to one another which is in a range from 1.5: 1.0 to 2.0: 1.0.

The area ratio of open to closed areas in each of the at least two perforated plates is advantageously greater than 50%. In this way, sufficient areas are available for the separation of fat particles still contained in the exhaust air. If the area ratio remains below 55%, the perforated sheets still have a stability that is sufficient for a mere Attachment of the perforated plates to the two second opposite side walls of the fat separator cartridge.

The holes in the at least two perforated sheets preferably each have a diameter in a range from 1 mm to 5 mm. In this way it can be achieved that the holes have a size at which, on the one hand, relatively high capillary forces develop and, on the other hand, the holes are prevented from clogging up quickly. The holes particularly preferably each have a diameter of 3 mm.

The base structure of the first guide unit of the two-part guide device preferably has a first base plate on which the first flow lamellae are arranged, and a second base plate which is arranged at a distance from the first base plate in the trough-like area of the base of the second guide unit and a collecting tray for provides separated fat particles.

In order to advantageously support that fat particles that have dripped onto the first base plate of the base structure of the first guide unit slide into the drip tray formed by the second base plate, the first base plate preferably has two base plate halves which, based on a vertical center axis M _{L of} the two-part Guide device containing plane E _L , are mirror-symmetrical and are arranged to the plane E _L at an angle of inclination which is in a range of 95 ° to 105 °.

The second base plate of the base structure of the first guide unit preferably has a circumferential, inwardly directed curvature which, in cooperation with a circumferential drainage edge of the first base plate which is spaced apart and points in the direction of the second base plate, provides a droplet trap for separated fat particles. In this way it is advantageously ensured that separated fat particles reach the fat particle collecting tray provided by the second base plate in a secure manner.

Naturally, cookware of different wall heights is used on a hob. In order to nevertheless supply the exhaust air generated accordingly as completely as possible to the exhaust air conveyor channel, a lamellar grille that can be inserted into the exhaust air inlet opening of the exhaust air conveyor channel is preferably provided. The lamellar grille has a large number of evenly spaced lamellas, which are mirror-symmetrical in relation to the vertical center plane E _{A of} the exhaust air conveyor channel and each point away from the plane E _{A of} the exhaust air conveyor channel with the same inclination. The The inclination of the lamellas is defined by an angle, which in turn is defined by a tangential plane of the outer surface of that lamella, which is arranged adjacent to the vertical center plane E _{A of} the exhaust air conveyor channel, and by the central plane E _{A of} the exhaust air conveyor channel, the tangential plane containing a line, in which a plane E _{0 of} the exhaust air inlet opening and the plane E _A intersect. The angle defining the inclination of the slats is preferably in a range from 20 ° to 30 °.

The lamellar grille is preferably detachably attached to the two second opposite side walls of the fat separation cartridge. This allows easy cleaning of the louvred grille and easy access to the inside of the exhaust air duct.

In order to optimally adapt the extraction of the exhaust air generated on a hob to the conditions prevailing on a hob - for example to the operation of only individual cooking zones or the operation of all cooking zones - a closing device is preferably provided, by means of which either one half of the exhaust air duct is completely released or only one half of both conveyor channel halves. In this way it is furthermore advantageously achieved that the volume of exhaust air sucked into the exhaust air conveying channel is always the same, regardless of the respective position of the closing device.

The closure device is preferably supported in a slidable manner - in the sense of a sliding carriage - by respective upper edges of the two second opposite side walls of the fat separation cartridge.

An indirect or direct motor drive can alternatively serve to drive the impeller of the radial fan of the trough hood according to the invention. The indirect motor drive is preferably provided by a motor-driven belt drive and the direct motor drive by a brushless DC motor.

Further details and advantages of the invention emerge from the description of an exemplary embodiment of a trough hood according to the invention, which is explained in more detail below with reference to the accompanying figures. The figures are for illustrative purposes and are not true to scale.

• Figur 1 eine schematische Schnittansicht eines Ausführungsbeispiels eines erfindungsgemäßen Muldenabzugs mit Veranschaulichung des Strömungsverlaufs der Abluft,
• Figur 2a die schematische Schnittansicht von Figur 1 ohne Veranschaulichung des Abluftströmungsverlaufs,
• Figur 2b eine Lupenansicht eines in Figur 2a durch Einkreisung gekennzeichneten Details,
• Figur 3 eine schematische Explosionszeichnung der einzelnen Vorrichtungskomponenten des in den Figuren 1 und 2 veranschaulichten Muldenabzugs,
• Figur 4 eine schematische dreidimensionale Darstellung der in Figur 3 u.a. veranschaulichten zweiten Leiteinheit und der Fettabscheidekartusche mit damit verbundener erster Leiteinheit,
• Figur 5 eine dreidimensionale schematische Detaildarstellung der in Figur 4 veranschaulichten Fettabscheidekartusche und damit verbundener erster Leiteinheit,
• Figur 6 eine schematische Draufsicht des in den Schnittansichten der Figuren 1 und 2 veranschaulichten spiralförmigen Lüftergehäuses,
• Figur 7 eine schematische Draufsicht des in den Figuren 1 und 2 veranschaulichten spiralförmigen Lüftergehäuses, und
• Figur 8 eine schematische Schnittansicht des Lamellengitters.

In the figures show:

• Figure 1 a schematic sectional view of an embodiment of a trough hood according to the invention with an illustration of the flow path of the exhaust air,
• Figure 2a the schematic sectional view of Figure 1 without illustration of the exhaust air flow,
• Figure 2b a close-up view of an in Figure 2a details marked by circling,
• Figure 3 a schematic exploded view of the individual device components of the in the Figures 1 and 2 illustrated recess discharge,
• Figure 4 a schematic three-dimensional representation of the in Figure 3 including the illustrated second guide unit and the fat separator cartridge with the first guide unit connected to it,
• Figure 5 a three-dimensional schematic detailed representation of the in Figure 4 illustrated fat separator cartridge and associated first guide unit,
• Figure 6 a schematic plan view of the in the sectional views of FIG Figures 1 and 2 illustrated spiral fan housing,
• Figure 7 a schematic plan view of the in the Figures 1 and 2 illustrated spiral fan housing, and
• Figure 8 a schematic sectional view of the louvred grille.

Using schematic sectional drawings, the Figures 1 and 2a a preferred embodiment of a trough hood 10 according to the invention. Figure 1 differs from Figure 2a only insofar as it also illustrates the flow path of the extracted exhaust air indicated by arrows.

As in the Figures 1 and 2a As shown, the trough extractor 10 is arranged in a cuboid space 1 below a hob level 2. The required installation width or installation depth for the hob extractor 10 is determined by the spiral-shaped fan housing 14, and the required installation height is determined by an area of a grease trap cartridge 36 which, in relation to a plane E _{O of} the hob, extends vertically from a fan suction opening 24 of the fan housing 14 protrudes and turns into a extends central recess of the hob 2 and provides an exhaust air inlet opening 12 there, which has a central axis M common to the fan suction opening 24.

With additional reference to Figure 3 one takes the Figures 1 , 2a Furthermore, that the spiral fan housing 14 has a bottom wall 16, a top wall 28 and an outer wall 30. A radial fan 18 is arranged on the bottom wall, the impeller 20 of which carries a plurality of evenly spaced impeller blades 22. The axis of rotation of the impeller 20, which in the illustrated embodiment is rotated by a motorized belt drive 106, is coaxial with the central axis of the exhaust air inlet opening 12 and the fan suction opening 24. This arrangement of the radial fan 18 makes it possible to design the impeller 20 with a diameter that allows a rotational frequency that on the one hand excludes undesirable noise nuisance generated by the fan and on the other hand ensures the required suction power. The impeller blades 22 are curved backwards with respect to a direction of rotation of the impeller 20.

The Figures 1 , 2a furthermore show the annular space 26 which is adjacent to the impeller blades 22 and which is delimited by the bottom wall 16, the top wall 28 and the outer wall 30 of the spiral fan housing 14. As noted at the outset, the flow cross-section of the annular space must be continuously increased in spiral fan housings. For this purpose, the outer radius of the top wall of the fan housing is usually increased continuously while the inner radius remains the same, but with the associated disadvantage that the installation width of the fan housing and the associated space required are increased. To avoid this disadvantage, according to the invention and, as in particular from the Figures 6 and 7th can be seen, the flow cross-section is continuously increased over a region 27 of the annular space 26 by the top wall 28 of the fan housing 14 having an unchanged outer radius with a reduced inner radius and the outer wall 30 of the fan housing 14 an increased height.

The Figures 1a , 2a and 3 it can also be seen that above the impeller 20 and below the fat separator cartridge 36, which is box-shaped in the illustrated embodiment of the inventive trough extractor 10, a two-part guide device is arranged, which comprises a first guide unit 46 and a second guide unit 48. By virtue of this two-part guide device, the impeller blades 22 are acted upon by the exhaust air flow sucked off via an exhaust air conveying channel 38 provided by the grease separating cartridge 36, radially symmetrically and evenly distributed over 360 °.

With a view to Figure 7 it can be seen that the impeller blades 22 have only a slight curvature. This curvature results from a ratio of the blade length L to its radius of curvature L - L / R - and this ratio is preferably in a range from 0.5 to 0.7. Furthermore you can Figure 7 infer that the impeller blades are of a relatively great length. Based on a difference between the radii which determine an inner and outer circular path on which the ends of the impeller blades 22 move, the length of the impeller blades is approximately 3 to 3.7 times this difference.

The second guide unit 48 is firmly connected to an underside of the top wall 28 of the fan housing 14 and has a circular base 50 on which the flow grid ring 52 is arranged, which has a plurality of equally spaced second flow lamellae, which, based on a central axis M _{L of} the two-part guide device, coaxial with the central axis M of the exhaust air inlet opening 12 and fan intake opening 24, are aligned radially symmetrically. The fixed connection of the second guide unit 48 to an underside of the top wall 28 of the fan housing 14 and the flow grille ring 52 fixed in this way also provides protection against intrusion for the user of the trough extractor from injury.

The first guide unit 46 is firmly connected to a circumferential lower edge 44 of the box-shaped fat separation cartridge 36 and has a base structure 56 which is arranged within the flow grille ring 52 on the base 50 of the second guide unit 48 and has a plurality of equally spaced first flow lamellae 58 which, relative to the vertical central axis M _{L of} the two-part guide device, are radially aligned and communicate with the second flow lamellae 54 of the flow grid ring 52. The number of second flow lamellae 54 exceeds that of the first flow lamellae 58 by a multiple. This multiple is in a range from 6 to 15 in order to optimize the air admission to the impeller blades.

The distance between the flow grille ring 52 of the second guide unit 48 and the ends of the impeller blades 22 pointing in the direction of the flow grille ring 52 (schematically in particular in FIG Figure 7 shown) is selected such that the impeller blades 22 are acted upon by a substantially laminar exhaust air flow despite the air turbulence that inevitably occurs when flowing through the flow grille ring 52. To achieve this, the flow grid ring 52 has an outer radius that is 15 to 25 mm smaller than the radius determining the inner circular path 21, on which the ends of the impeller blades 22 pointing in the direction of the flow grid ring 52 move when the radial fan 18 is in operation .

Like in particular from Figure 3 , but also from Figure 4 As can be seen, the circular floor 50 of the second guide unit 48 has a trough-like area 51, within which the floor structure 56 of the first guide unit 46 is arranged. This trough-like area 51 ensures that fat droplets, which are separated by the first and second fat separating devices 40, 42 arranged in the exhaust air conveying channel 38 and picked up by the base structure 56, cannot get onto the impeller blades 22 of the radial fan 18.

How to get out of the Figures 1 to 4 As can also be seen, the floor structure 56 of the first guide unit 46 has a first, ie upper floor plate 57 and a second, ie lower floor plate 59. The first base plate 57 carries the aforementioned first flow lamellae 58 and absorbs the fat particles which are separated by the second fat separator 42, which is connected downstream of the first fat separator 40, and the second base plate 59 serves as a collecting tray for separated and initially from the first base plate 57 ingested fat particles. In order to support that the fat particles picked up by the first base plate 57 reach the collecting tray provided by the second base plate 59, the first base plate 57 is formed by two base plate halves which, based on a plane E containing the vertical center axis M _{L of} the two-part guide device _L , are mirror symmetrical and are arranged to the plane E _L at an angle of inclination which lies in a range from 95 ° to 105 °.

In order to prevent the exhaust air flow from dragging along fat particles that are located on the first base plate 57, circumferential end edges of the first and second base plates form a droplet trap. As from the Figures 1 , 2a and the magnifying glass view of Figure 2b As can be seen, for this purpose a circumferential end edge 61 of the second base plate 59 has an inwardly directed curvature 63. This curvature 63 forms a droplet trap in cooperation with a circumferential end edge 65 of the first base plate 57, which is inclined downward as a drip edge and is spaced from the second base plate 59.

In order to remove entrained fat particles from the exhaust air to the greatest possible extent, first and second fat separation devices 40, 42 are provided in the exhaust air conveyor channel 38 formed by the fat separation cartridge 36. As in particular from the also illustrating the flow path of the extracted exhaust air Figure 1 as well as the three-dimensional representation of Figure 5 As can be seen, the exhaust air conveying channel 38 has two exhaust air conveying channel halves 68, 70 in relation to a plane E _A containing its vertical central axis M _A. Figure 1 one can see at a glance that the vertical central axis M _{A is} coaxial with the aforementioned common central axis M of Exhaust air inlet opening 12 and fan suction opening 24 and is also coaxial with the vertical central axis M _{L of} the two-part guide device.

In relation to the vertical center plane E _{A of} the exhaust air conveying channel 38, the first fat separating device 40 has a pair of first air guiding devices 72, 74; 72 ', 74', a pair of second air guiding devices 76, 78; 76 ', 78' and a pair of third air guiding devices 80, 82; 80 ', 82'. In relation to a plane E _AH containing a vertical central axis M _{AH of} the conveying channel halves 68, 70, the air guiding devices of the first, second and third pair of air guiding devices are each arranged mirror-symmetrically: a first air guiding device 72, 74, 72 ', 74' is in each case from the plane E _{AH of} the exhaust air conveyor duct half 68, 70 spaced apart and arranged and prepared adjacent to the exhaust air inlet opening 12 - as in FIG Figure 1 illustrates - to direct the exhaust air flow in the direction of a respective second air guiding device 76, 78, 76 ', 78'; the respective second air guiding device 76, 78, 76 ', 78' is in each case spaced apart from the respective first air guiding device 72, 74, 72 ', 74' and is arranged and prepared along a section of the plane E _AH - as in FIG Figure 1 illustrates - removing fat particles from the exhaust air stream and directing the exhaust air stream in the direction of a respective third air guiding device 80, 82, 80 ', 82'; and the respective third air guide device 80, 82, 80 ', 82' is arranged and prepared at a distance from the respective second air guide device 76, 78, 76 ', 78' and from the respective plane E _AH - as in FIG Figure 1 illustrates - to separate fat particles from the exhaust air flow and direct the exhaust air flow in the direction of the downstream second separation device 42.

How to do the Figures 1 , 2 and particularly Figure 5 takes further, each pair of the first air guide devices 72, 74, 72 '74' and each pair of the third air guide devices 80, 82, 80 ', 82' each have a first first air guide device 72, 72 'and each a first third air guide device 80, 80 ', which are each formed integrally with an inner surface of two first opposing side walls 60, 62 of the grease trap cartridge 36, in such a way that - as in FIGS Figures 1 , 2 and 5 illustrates - the first air guide device 72, 72 'in each case protrudes as a nose-shaped element and the first third air guide device 80, 80' as a shell-shaped element protrudes into the respective conveyor channel half 68, 70. Each pair of the first air guide devices 72, 74, 72 ', 74' and each pair of the third air guide devices 80, 82, 80 ', 82' furthermore each have a second first air guide device 74, 74 'and a second third air guide device 82, 82' , which are provided by a first module 84 which can be inserted into the exhaust air conveying channel 38 and is detachably fastened to two second opposite side walls 64, 66 of the fat separation cartridge 36.

As illustrated, the first module 84 is designed in the form of an anchor and has an anchor head 86 with a diamond-shaped cross-section, the head halves of which are mirror-symmetrical in relation to the center plane E _{A of} the exhaust air conveyor channel 38 and each protrude like a nose into the respective exhaust air conveyor channel half 68 and 70. The first module 84 also has a slender anchor neck 87 that carries the anchor head 86 and is mirror-symmetrical to the center plane E _A and, with reference to the plane E _A , two mirror-symmetrical anchor arms 88 and 90, each of which protrude like a shell into the respective conveying channel half 68 and 70 .

How to do the Figures 1 , 2 and 5 is also removed, each pair of the second air guide devices 76, 78, 76 ', 78' is each inserted by a second module 92, 92 'which can be inserted into the respective exhaust air conveying channel half 68, 70 and is detachably attached to the two second opposite side walls 64, 66 of the fat separation cartridge 36. provided. The second modules 92 and 92 'are each designed in the form of an anchor and each have a slender anchor neck 93, 93' that is mirror-symmetrical to the center plane E _{AH of} the respective conveying channel half 68, 70 and, in relation to the plane E _AH , two mirror-symmetrical anchor arms 94, 97 and 94 ', 97', each pointing away from the plane E _{AH in} a shell-like manner.

As illustrated, the two mirror-symmetrical anchor arms 94, 97 and 94 ', 97' of each second module 92 and 92 'are each carried by an anchor body 95, 95' which, based on the plane E _{AH, of} the respective conveyor channel half 68, 70 , is mirror symmetrical. How one in particular Figure 5 removes, the anchor body 95, 95 'is each hollow and is formed by two anchor body surfaces that combine in the plane E _AH at an acute angle.

The second fat separating device 42, which can also be referred to as a fine separating device, is connected downstream of the first fat separating device 40 and is used to separate the last entrained fat particles from the exhaust air flow.

According to the above-described embodiment of a trough extractor 10 according to the invention, the second fat separating device 42 is provided by two spaced, shell-like perforated plates 96, 98 which are rotationally symmetrical to the central axis M _{A of} the exhaust air conveyor duct 38. In order to achieve in a manner that is advantageous for the separation efficiency that the perforated plates 96, 98 are partially flowed around and partially flowed through by the exhaust air flow, the perforated plates have different diameters and, as from the Figures 1 , 2 and 5 it can be seen that the perforated plate 96, which has a larger diameter, is above the one Perforated plate 98 having a smaller diameter and arranged below the third air guiding devices 80, 82, 80 ', 82'.

The area ratio (not shown) of the respective perforated plates 96, 98 of open to closed areas is advantageously greater than 50%. In this way, sufficient areas are available for the separation of fat particles still contained in the exhaust air. Even with an area ratio of less than 55%, the perforated plates still have a stability that is sufficient for merely fastening them to the two second opposite side walls 64, 66 of the fat separating cartridge 36.

The holes (not shown) in the perforated plates 96, 98 each preferably have a diameter between 1 mm and 5 mm. The size of the holes is such that, on the one hand, relatively high capillary forces develop and, on the other hand, it prevents the holes from clogging up relatively quickly. The holes particularly preferably have a diameter of 3 mm.

From the Figures 1 , 2a , 3 and 8th it can also be seen that a lamellar grille 100 which can be inserted into the exhaust air inlet opening 12 of the exhaust air conveying channel 38 and which has a plurality of evenly spaced lamellae 102 is provided. How out Figure 8 As can be seen, the lamellas 102 are designed mirror-symmetrically to the vertical center plane E _{A of} the exhaust air conveyor duct 38 and point away from the plane E _A with the same inclination. As in Figure 8 illustrated, the inclination of the slats 102 is determined by an angle of inclination α, which in turn is defined by a tangential plane E _{T of} the outer surface of that slat 102, which is arranged adjacent to the central plane E _{A of} the exhaust air conveyor channel 38, and by the plane E _{A of} the exhaust air conveyor channel 38. Here, the tangential plane E _{T contains} a line in which the planes E _A and E _T intersect. The angle α is preferably in a range between 20 ° and 30 °. The louvred grille 100 designed in this way takes into account, on the one hand, the fact that cookware of different wall heights is naturally used on a hob and, on the other hand, the endeavor to ensure that the correspondingly generated exhaust air is supplied as completely as possible to the hob hood. The latter is achieved in an advantageous manner by the lamellae 102 of the lamellar grille 100 which can be inserted into the exhaust air inlet opening of the exhaust air conveyor channel, which are arranged at a particular angle of inclination. In order to be able to easily clean the lamellar grille and also to allow easy access to the interior of the exhaust air conveying channel 38, the lamellar grille is detachably connected to the two second opposite side walls 64, 66 of the fat separation cartridge 36.

The Figures 1 and 2a furthermore show a closing device 104 which is provided in the exhaust air inlet opening 12 of the exhaust air conveying channel 38 and which is arranged directly above the louvred grille 100. The louvred grille 100 carries the closing device 104 slidably in the sense of a slidable carriage. Alternatively, the closing device 104 can also be slidably supported by the respective upper free edges 67, 69 of the two second opposite side walls 64, 66 of the fat separation cartridge 36. The closing device 104 can be moved in such a way that it releases the exhaust air inlet opening 12 either for one of the two exhaust air conveyor channel halves 68, 70 or only for one half of each of the two conveyor channel halves. In this way, the hob extractor according to the invention can be optimally adapted to the conditions prevailing on a hob, ie depending on whether the hob is only operated with individual hotplates or even all hotplates. In addition, the sealing device 104, which can be displaced in this way, advantageously ensures that the volume of exhaust air sucked into the exhaust air delivery channel 38 is always constant.

List of reference symbols

1

= Space

2

= Hob

10

= Device

12

= Exhaust air inlet opening

14th

= spiral fan housing

16

= Bottom wall of fan housing

18th

= Radial fan

20th

= Impeller

22nd

= Impeller blades

21st

= inner circular path of the impeller blades

23

= outer circular path of the impeller blades

24

= Fan intake opening

M.

= common vertical center axis of exhaust air inlet opening and fan intake opening

26th

= Annular space of fan housing

27

= Area of annulus

28

= Ceiling wall of fan housing

30th

= Outer wall of fan housing

32

= Exhaust air outlet

34

= Side wall

36

= Grease trap cartridge

E ₀

= Level of the exhaust air inlet opening

38

= Exhaust air duct

M _A

= vertical center axis of the exhaust air duct

40

= first fat separator

42

= second fat separator

44

= circumferential lower edge of the grease trap cartridge

46

= first lead unit

48

= second lead unit

M _L

= common vertical center axis of the first and second guide unit

50

= circular bottom of the second guide unit

51

= trough-like area of the bottom of the second guide unit

52

= Flow grid ring

54

= second flow lamellae

56

= Floor structure of the first guide unit

57

= first floor slab of the floor structure

58

= first flow lamellas

59

= second base plate of the floor structure

61

= circumferential end edge of the second base plate

63

= inward curvature of the circumferential end edge of the second base plate

65

= circumferential end edge of the first base plate designed as a drip edge

60, 62

= first opposite side walls of the grease trap cartridge

64, 66

= second opposite side walls of the grease trap cartridge

67, 69

= upper free edges of the second opposite side walls

E _A

= Level containing the vertical central axis of the exhaust air conveyor duct

68, 70

= Conveyor channel halves of the exhaust air conveyor channel

72, 74; 72 ', 74'

= Pairs of first air ducting devices

76, 78; 76 ', 78'

= Pairs of second air ducting devices

80, 82; 80 ', 82'

= Pairs of third air ducting devices

M _AH

= vertical central axis of the conveyor channel halves

E _AH

= Level that contains the vertical central axis of the conveyor channel halves

72, 72 '

= first first air ducting devices

80, 80 '

= first third air ducting devices

74, 74 '

= second first air ducting devices

82, 82 '

= second third air ducting devices

84

= first module

86

= Anchor head

87

= Anchor neck

88, 90

= Anchor arms

92, 92 '

= second modules

93, 93 '

= Anchor neck

94, 97; 94 ', 97'

= Anchor arms

95, 95 '

= Anchor body

96, 98

= Perforated sheets

100

= Louvred grille

102

= Slats

E _T

= Tangential plane

104

= sliding locking device

106

= motorized belt drive

Claims (28)

1. A device (10) for trough extraction of exhaust air generated on a cooking hob, comprising:

   an exhaust air inlet opening (12) arranged in a central recess of a cooking hob (2);

   a spiral-shaped fan housing (14) having a motor-driven radial fan (18) arranged on a bottom wall (16) of the fan housing (14), the impeller (20) of the radial fan (18) carrying a plurality of uniformly spaced impeller blades (22),

   the fan housing (14) having a fan suction opening (24) spaced apart from the exhaust air suction opening (12), and the fan suction opening (24) and the exhaust air suction opening (12) having a common vertical center axis (M),

   the fan housing (14) having an annular space (26) arranged adjacent to the impeller blades (22), and the annular space (26) being defined by the bottom wall (16), a top wall (28) and an outer wall (30) of the fan housing (14), the fan housing (14) further having an exhaust air outlet opening (32) provided by a free end portion of the bottom, top and outer walls (16, 28, 30) of the fan housing (14) and by a side wall (34) opposite the outer wall (30);

   a grease separation cartridge (36) releasably connected with the exhaust air inlet opening (12) and the fan suction opening (24), the grease separation cartridge (36) forming an exhaust air conveying duct (38) arranged vertically to a plane (E_O) of the exhaust air inlet opening (12), the exhaust air conveying duct (38) having a vertical center axis (M_A) coaxial to the vertical center axis (M) of the exhaust air inlet opening (12) and the fan suction opening (24), wherein first and second grease separation means (40, 42) are arranged in the exhaust air conveying duct (38); and

   a two-part guide system having first and second guide units (46, 48) configured to radially distribute the exhaust air evenly and symmetrical in radial direction over 360° onto the impeller blades (22), characterized in that

   the first and second guide units (46, 48) have a common vertical center axis (M_L) coaxial with the center axis (M_A) of the exhaust air conveying duct (38), wherein

   the second guide unit (48) is fixedly connected to an underside of the top wall (28) of the fan housing (14) and has a circular bottom (50) arranged above the impeller (20) onto which and adjacent to the impeller blades (22) a flow grid ring (52) is arranged, which flow grid ring (52) has a plurality of uniformly spaced second flow lamellas (54) which are radially aligned with respect to the vertical center axis (M_L), and wherein

   the first guide unit (46) is fixedly connected to a circumferential lower edge (44) of the grease separation cartridge (36) and has a bottom structure (56) which is arranged within the flow grid ring (52) on the bottom (50) of the second guide unit (48) and has a plurality of uniformly spaced first flow lamellas (58) which are radially aligned with respect to the vertical center axis (M_L) and communicate with the second flow lamellas (54).
2. The device (10) according to claim 1, wherein the impeller (20) of the radial fan (18) has a diameter in a range of 400 mm to 440 mm, and wherein the impeller blades (22) are curved backwardly with respect to a direction of rotation of the impeller (20).
3. The device (10) according to claim 1 or 2, wherein
   the number of second flow lamellas (54) exceeds the number of first flow lamellas (58) several times, and wherein
   the multiple is in a range of 6 to 15 times.
4. The device (10) according to one of the preceding claims, wherein a continuously increasing flow cross section of the annular space (26) of the fan housing (14) is increased in an area (27) of the annular space (26) by the fact that the top wall (28) of the fan housing (14) at an unchanged outer radius has a reduced inner radius and the outer wall (30) of the fan housing (14) has an increased height.
5. The device (10) according to one of the preceding claims, wherein the flow grid ring (52) has an outer radius which is 10 mm to 15 mm smaller than a radius defining an inner circular path (21) on which path the ends of the impeller blades (22) move during operation of the device (10), while pointing in the direction of the flow grid ring (52).
6. The device according to one of the preceding claims, wherein
   the exhaust air conveying duct (38) formed by the grease separation cartridge (36) is box-shaped and has two first opposite side walls (60, 62) and two second opposite side walls (64, 66), wherein
   the first guide unit (46) is fixedly connected with circumferential lower edges (44) of the side walls (60, 62, 64, 66), and wherein
   an area (51) of the bottom (50) of the second guide unit (48), onto which the bottom structure (56) of the first guide unit (46) is arranged, is formed in a tub-like manner.
7. The device (10) according to claim 6, wherein the exhaust air conveying duct (38) of the grease separation cartridge (36), with respect to a plane (E_A) containing its vertical center axis (M_A), has two exhaust air conveying duct halves (68, 70) in which mirror-symmetrically to the plane (E_A), the first grease separation means (40) comprises a pair of first air guide units (72, 74; 72', 74'), a pair of second air guide units (76, 78; 76', 78') and a pair of third air guide units (80, 82; 80', 82'), respectively, wherein
   the air guide units of the first, second and third pairs of air guide units each are arranged mirror-symmetrically with respect to a plane (E_AH) containing a vertical center axis (M_AH) of the conveying duct halves (68, 70), such that
   a first air guide unit (72, 74; 72', 74') is always spaced apart from the plane (E_AH) of the exhaust air conveying duct half (68, 70) and arranged adjacent to the exhaust air inlet opening (12), and is configured to direct an exhaust air stream entering through the exhaust air inlet opening (12), in the direction of a second air guide unit (76, 78; 76', 78'),
   the respective second air guide unit (76, 78; 76', 78') is spaced apart from the respective first air guide unit (72, 74; 72', 74') and arranged along a portion of the plane (E_AH), and is configured to separate grease particles from the exhaust air stream and to direct the exhaust air stream in the direction of a respective third air guide unit (80, 82; 80', 82'), and
   the respective third air guide unit (80, 82; 80', 82') is spaced apart from both the respective second air guide unit (72, 74; 72', 74') and the plane (E_AH), and is configured to separate grease particles from the exhaust air stream and to direct the exhaust air stream in the direction of the second grease separation means (42).
8. The device (10) according to claim 7, wherein
   each pair of the first air guide units (72, 74; 72', 74') and each pair of the third air guide units (80, 82; 80', 82') each comprises a first first air guide unit (72, 72') and a first third air guide unit (80, 80'), respectively, each thereof being integrally formed with an inner surface of the two first opposite side walls (60, 62) of the grease separation cartridge (36), such that each of the respective first first air guide unit (72, 72') projects in a nose-like manner into the respective conveying duct half (68, 70), thereby providing a respective first first air guide unit (72, 72'), and each of the respective first third air guide unit (80, 80') projects in a shell-shaped manner into the respective conveying duct half (68, 70), thereby providing a respective first third air guide unit (80, 80'), wherein
   each pair of the first air guide units (72, 74; 72', 74') and each pair of the third air guide units (80, 82; 80', 82') each comprises a second first air guide unit (74, 74') and a second third air guide unit (82, 82'), which are provided by a first module (84) configured to be inserted into the exhaust air conveying duct (38) and to releasably secured to the two second opposite side walls (64, 66) of the grease separation cartridge (36), wherein the module (84) is of an anchor-shaped design and has an anchor head (86) with a rhombic-shaped cross section, the head halves of which are with respect to the plane (E_A) of the exhaust air conveying duct (38) of a mirror-symmetrical design, with each head half projecting in a nose-like manner into the respective exhaust air conveying duct half (68, 70), thereby providing a second first air guide unit (74, 74') each, wherein the first module (84) further comprises an anchor neck (87) carrying the anchor head (86) and being mirror-symmetrical with respect to the plane (E_A), and two mirror-symmetrical anchor arms (88, 90)which, with respect to the plane (E_A), are mirror-symmetrical with each thereof projecting in a shell-like manner into the respective exhaust air conveying duct half (68, 70), thereby providing a second third air guide means (82, 82') each, and wherein
   each pair of said second air guide means (76, 78; 76', 78') is provided by a second module (92, 92') insertable into the respective exhaust air conveying duct half (68, 70) and releasably secured to the two second opposite side walls (64, 66) of the grease separation cartridge (36), wherein each module (92, 92') is of an anchor-shaped design and has an anchor neck (93, 93') being mirror-symmetrical with respect to the plane (E_AH) of the conveying duct half (68, 70), and two anchor arms (94, 97; 94', 97') which, with respect to the plane (E_AH), are mirror-symmetrical, with each anchor arm pointing away from the plane (E_AH) in a shell-like manner, thereby providing a pair of the second air guide means (76, 78; 76', 78') each.
9. The device (10) according to claim 8, wherein each second module (92, 92') has an anchor body (95, 95') which carries the anchor arms (94, 97; 94', 97') and is formed mirror-symmetrically with respect to the respective plane (E_AH).
10. The device (10) according to claim 9, wherein the anchor bodies (95, 95') each have two anchor body surfaces joining together in the plane (E_AH), with the free ends of the anchor body surfaces each being arranged at an acute angle with respect to the plane (E_AH).
11. The device (10) according to one of claims 6 to 10, wherein the second grease separation means (42) is arranged below the third air guidance unit (80, 82; 80', 82') and provided by at least two perforated plates (96, 98) spaced apart from one another, with each thereof being shaped like a bowl and rotationally symmetrical with respect to the center axis (M_A) of the exhaust air conveying duct (38).
12. The device (10) according to claim 11, wherein the at least two perforated plates (96, 98) have different diameters which differ such that the at least two perforated plates (96, 98) are partially surrounded and partially traversed by the exhaust air flow.
13. The device (10) according to claim 11 or 12, wherein a ratio of open to closed areas in each of said at least two perforated plates (96, 98) is greater than 50%.
14. The device (10) according to one of claims 11 to 13, wherein each of at least two perforated plates (96, 98) has holes with a diameter in a range from 1 mm to 5 mm.
15. The device (10) according to one of claims 6 to 14, wherein the bottom structure (56) of the first guide unit (46) comprises a first bottom plate (57) on which the first flow lamellas (58) are arranged, and a second bottom plate (59) spaced apart from the first bottom panel (57), the second bottom plate (59) providing a collecting tray for separated grease particles and being arranged in the tub-like area (51) of the bottom (50) of the second guide unit (48).
16. The device (10) according to claim 15, wherein the first bottom plate (57) has two bottom plate halves which, with respect to a plane (E_L) containing the vertical center axis (M_L) of the two-part guide means, are mirror-symmetrical and are each arranged at an angle of inclination to the plane (E_L) which angle is in a range from 95° to 105°.
17. The device (10) according to claim 15 or 16, wherein a circumferential end edge (61) of the second bottom plate (59) has an inwardly directed curvature (63) which, in cooperation with a circumferential drip edge (65) of the first bottom panel (57) spaced apart therefrom and pointing in the direction of the second bottom plate (59), provides a droplet trap for separated grease particles.
18. The device (10) according to one of claims 6 to 17, wherein the device (10) further comprises a louvre grill (100) insertable into the exhaust air inlet opening (12).
19. The device (10) according to claim 18, wherein
    the louvre grill (100) has a multitude of uniformly spaced lamellas (102) which, with respect to the plane (E_A) of the exhaust air conveying duct (38), are of a mirror-symmetrical design and each thereof with the same inclination points away from the plane (E_A) of the exhaust air conveying duct (38), wherein
    the inclination is defined by an angle (α), which angle (α) is defined by a tangential plane (E_T) of the outer surface of the lamella (102) which is disposed adjacent to the plane (E_A) of the exhaust air conveying duct (38), and by the plane (E_A) of the exhaust air conveying duct (38), wherein the tangential plane (E_T) includes a line where the plane (E₀) of the exhaust air inlet opening (12) and the plane (E_A) intersect, and wherein the angle (α) is in a range between 20° and 30°.
20. The device (10) according to one of claims 18 or 19, wherein the louvre grill (100) is releasably secured to the two second opposing side walls (64, 66) of the separation cartridge (36).
21. The device (10) according to one of claims 6 to 20, wherein the device (10) further comprises a slidable closure means (104) disposed in the exhaust air inlet opening (12) of the exhaust air conveying duct (38).
22. The device (10) according to claim 21, wherein the closure means (104) completely releases either one of the two conveying duct halves (68, 70) or only one half of each of the two conveying duct halves (68, 70).
23. The device (10) according to claim 21 or 22, wherein the two second opposite side walls (64, 66) of the separation cartridge (36) on their respective upper edges (67, 69) slidably support the closure means (104).
24. The device (10) according to one of the preceding claims, wherein the impeller (20) of the radial fan (18) is driven by either an indirect motor drive or a direct motor drive.
25. The device (10) according to claim 24, wherein the indirect motor drive is a motor belt drive (106).
26. The device (10) according to claim 23, wherein the direct motor drive is a brushless DC motor.
27. Cooking hob (2) comprising a device (10) according to one of claims 1 to 26.
28. Cooking hob (2) according to claim 27, wherein the closure means (104) is in a plane which is coplanar with a plane defined by the cooking hob (2).

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