Hob extractor device

Abstract

We describe a hob extractor device (1), comprising: a hob (2) having at least one opening (2b); a suction fan (9) that is preferably located below said hob (2);,a suction unit (10) in operative fluid connection with an environment (E) above said hob (2) on one side and with said suction fan (9) on the other side, which suction unit (10) is located in an area of said opening (2b) and constitutes a suction duct for extracting cooking vapours by means of said suction fan (9); a lifting unit (11) for moving the suction unit (10) upwards and downwards with respect to said opening (2b) between a first position, in which an upper end of said suction unit (10) is located at a first height with respect to the hob (2), and a second position, in which said upper end of said suction unit (10) is located at a second height with respect to the hob (2), said second height being greater than said first height; wherein said suction unit (10) comprises at least two separate duct elements (10a, 10b) that together form said suction duct and that are individually and / or jointly movable by said lifting unit (11) for placing said upper end of said suction unit (10) at said second position when both duct elements (10a, 10b) are moved upwards and for placing said upper end of said suction unit (10) at an intermediate position between said first position and said second position when only one of the duct elements (10a, 10b) is moved upwards.

Description

[0001] The invention relates to a hob extractor device, i.e., an extractor integrated in a kitchen hob, according to the preamble of claim 1.

[0002] The extractor comprises: a hob having at least one opening; a suction fan that is preferably located below said hob; a suction unit in operative fluid connection with an environment above said hob on one side and with said suction fan on the other side, which suction unit is located in an area of said opening and constitutes a suction duct for extracting cooking vapours (produced by the hob, i.e., by foodstuff prepared on the hob) by means of said suction fan; a lifting unit for moving the suction unit upwards and downwards with respect to (i.e., through) said opening between a first position, in which an upper end of said suction unit is located at a first height with respect to the hob, and a second position, in which said upper end of said suction unit is located at a second height with respect to the hob, said second height being greater than said first height.

[0003] A device according to the preamble of claim 1 is known from, e.g., DE 11 2017 002 182 A5, US 4,446,849 A or EP 3 018 420 A1.

[0004] The best height for extracting cooking vapours with the aid of such an extractor depends on the size of the cooking vessels used. Particularly with larger, i.e. taller pots or pans, it is advantageous if the extractor opening is positioned correspondingly high above the hob. The location of the extractor opening should be approximately at the same height as the upper rim cooking vessel or even slightly higher.

[0005] However, in the case of tall cooking vessels, this would require a correspondingly large extraction device, especially the movable suction unit, which in turn requires a correspondingly large amount of installation space below the hob, which means that valuable storage space is lost in the kitchen.

[0006] It is the object of the invention to overcome this disadvantage and to provide an extractor of the above type that can adapt to different suction heights without using up too much of the valuable stowage space below the hob.

[0007] This object is achieved by means of a hob extractor device having the characteristics as put forth in the appended claim 1.

[0008] Advantageous further embodiments of the hob extractor device according to the invention are defined in the dependent claims.

[0009] In accordance with the present invention, a hob extractor device comprises a hob having at least one opening, preferably in the form of a central opening. It further comprises a suction fan that is preferably located below said hob. A suction unit is in operative fluid connection with an environment above said hob on one side (for drawing in any cooking vapours) and with said suction fan on the other side (for evacuating or recycling said cooking vapours). The which suction unit is located in an area of said opening and constitutes a suction duct for extracting said cooking vapours (that are produced by the hob, i.e., by preparing food on said hob) by means of said suction fan. The device also comprises a lifting unit for moving the suction unit upwards and downwards with respect to said opening, i.e., through said opening, between a first position, in which an upper end of said suction unit is located at a first height with respect to the hob, and a second position, in which said upper end of said suction unit is located at a second height with respect to the hob. In the present context, said second height is greater than said first height. The hob extractor device is characterised in that said suction unit comprises at least two separate duct elements that together form said suction duct. They are individually and / or jointly movable by said lifting unit for placing said upper end of said suction unit at said second position when both duct elements are moved upwards and for placing said upper end of said suction unit at an intermediate position between said first position and said second position when only one of the duct elements is moved upwards. When none of the duct elements are moved, said upper end of said suction unit is preferably located level of the hob, i.e., an upper surface thereof.

[0010] In this way, the hob extractor device is equipped with a telescopic suction unit, the purpose of which is to be able to suck the cooking fumes and vapour from a location above the hob in order to have a better capture, especially when using higher pots or vessels. The suction unit can be positioned at at least three different levels of height in order to optimize the suction according to the type and the size of cooking pots used: Level 1: a suction zone or area of the suction unit (typically located at said upper end of said suction unit) is located on the same level as a top of the hob. This corresponds to a situation where none of the duct elements has been moved upwards. Level 2: the suction area is located at a height of about 60 - 65 mm (preferably) from the top of the hob. This corresponds to a situation where one of the duct elements has been moved upwards. Level 3: the suction area is preferably located at a height of about 130 - 150 mm (preferably) from the top of the hob. This corresponds to a situation where both of the duct elements have been moved upwards.

[0011] Of course, many intermediate levels can be reached by only partially extending (i.e., moving upwards) one or more of the duct elements. For instance, one could move one duct element completely upwards and only extend the other duct element to, e.g., half of its length.

[0012] The inventive concept thus enables to reach greater suction heights without requiring one single (long) suction duct that covers the entire range of available heights. By diving the suction duct into several duct elements, the total required stowage length for the duct can be reduced, thus saving valuable stowage space, because the individual duct elements are shorter than the obtainable total duct length (in the extended state thereof, i.e., with both duct elements moved upwards). This allows to have, e.g., additional drawers in a cupboard below the hob. Of course, this concept is not restricted to the use of two duct elements but could be extended to three or more of such elements.

[0013] The hob can be an induction hob. However, the invention is not restricted in this respect so that gas hobs and / or radiating electric hobs (e.g., with glass ceramic cover) could be employed as well (either alone or in any suitable combination).

[0014] In an embodiment of the device according to the invention said first height corresponds to a level of an upper surface of the hob.

[0015] This had been specified a "Level 1" further up and corresponds to a default standby state of the device. It can also be used to draw in vapours if very shallow (low) cooking vessels are used, e.g., pans.

[0016] In an embodiment of the device according to the invention said second height is 100 to 150 mm and said intermediate height is 60 to 65 mm above an upper surface of the hob, respectively.

[0017] This had been specified a "Level 2" and "Level 3" further up, respectively. The corresponding states can be used to draw in vapours if higher (deeper) or very high cooking vessels are used, e.g., pots.

[0018] Of course, the invention is not restricted to two above dimensions, which have - however - proved to be particularly advantageous in practice.

[0019] In an embodiment of the device according to the invention the duct elements are telescopically inserted into each other and can be moved individually with respect to the hub.

[0020] In this way, the best compromise can be achieved between total possible duct length, L, and reduced stowage size or height, S, which - for n duct elements of equal length - would be: S = L / n. However, the duct elements need not be of the same size (length).

[0021] In an embodiment of the device according to the invention the duct elements are of rectangular cross-section.

[0022] This has proved to be useful in practice although the invention is not limited to such geometries. For instance, circular or oval duct elements could be used instead, which may also be a question of design.

[0023] In an embodiment of the device according to the invention one of the duct elements is a lower duct element with larger cross-section and the other one of the duct elements is an upper duct element with smaller cross-section and is inserted into said lower duct element.

[0024] This is one preferred way of obtaining the above-mentioned telescopic arrangement of the duct elements. Again, there can be more than just two duct elements.

[0025] In an embodiment of the device according to the invention said upper duct element has a removable grid.

[0026] Such a grid prevents that (small and / or lightweight) objects are sucked into or the any objects fall (are dropped) into the device, which could damage the suction fan or block a vapour extraction passage. Furthermore, a removable grid (or the like) can allow access to an interior of the device, at least to the suction unit, e.g., for cleaning purposes.

[0027] In an embodiment of the device according to the invention a removable grease filter is located inside said upper duct element.

[0028] Such a filter prevents that grease soils and eventually damages the device, especially the suction fan. The above-mentioned removable grid allows easy access to said grease filter for cleaning purposes.

[0029] In an embodiment of the device according to the invention said upper duct element has a terminal protrusion with respect to the lower duct element, which can be (i.e., which extends) essentially in parallel with a plane of said hob.

[0030] In this way, the suction area can be enlarged in said intermediate position and in said second position (or in any position in which the upper duct element is raised with respect to the hob) without taking up too much stowage space below the hob.

[0031] In an embodiment of the device according to the invention said upper duct element has lateral openings for a passage of cooking vapours.

[0032] Typically, the upper duct element will also have upper openings, e.g., in said removable grid, that allow the passage of cooking vapours (e.g., when none of the duct elements have been extended). By further providing said lateral openings for a passage of cooking vapours, the suction area is enlarged and the extraction efficiency is thus enhanced.

[0033] In an embodiment of the device according to the invention said lifting unit comprises a motor means that is coupled to at least one of said duct elements.

[0034] In this way, operation of the device can be facilitated for the user. However, the invention does not exclude a manual operation thereof, i.e., for extending the suction duct. Preferably, however, the device has a user operation panel or interface that has dedicated operation elements for moving the duct elements, i.e., for choosing a suction height, either graduated or stepless.

[0035] In an embodiment of the device according to the invention said motor means is devised in the form of an electric motor with a worm screw forming part of a rotating screw jack. Preferably, the worm screw of the rotating screw jack is mechanically coupled (e.g., via a (hollow) drive shaft having a shoulder) at least with said upper duct element. Furthermore, the device is configured such that either a) said worm screw is further coupled (e.g., via a so-called translating nut or a threaded bushing that is fixed to said drive shaft) with said lower duct element for subsequently moving said upper duct element and said lower duct element or b) said lower duct element is mechanically coupled with said upper duct element for subsequently moving said upper duct element and said lower duct element.

[0036] In both cases a) and b), the result is a mechanical hysteresis, wherein first the upper duct element is moved upwards (e.g., by means of said drive shaft) when the electric motor rotates said worm screw thus operating the rotating screw jack. The upper duct element will then entail the lower duct element in its upward movement (case b)), thus further extending the suction duct (e.g., from level 2 to level 3). Or the lead screw itself will (e.g., via said translating nut) move the lower duct element upwards (case a)) together with the upper duct element, after the upper duct element has been initially moved upwards alone, thus further extending the suction duct (e.g., from level 2 to level 3).

[0037] It is assumed that the basic concept of converting rotation to translation by means of rotating jacks or the like is known to the skilled person.

[0038] It is also possible to first move both duct elements conjointly upwards (the upper duct element preferably being contained within the lower duct element) and to then extend only the upper duct element further once the lower duct element has reached its final position.

[0039] If there are separate motor means for both duct elements, which is possible within the scope of the present invention, one could move both of them competently independently from each other to obtain any possible suction height between level 1 and level 3 (cf. above).

[0040] In an alternative embodiment of the device according to the invention said motor means is devised in the form of a hydraulic piston driven by an electric motor. In this embodiment, a piston element is mechanically coupled at least with said upper duct element and either a) said piston is further coupled with said lower duct element for subsequently moving said upper duct element and said lower duct element or b) said lower duct element is mechanically coupled with said upper duct element for subsequently moving said upper duct element and said lower duct element.

[0041] This is an alternative way of realising the above-mentioned mechanical hysteresis for sequentially moving said upper and lower duct elements.

[0042] In an embodiment of the device according to the invention said suction unit and said lifting unit are placed in a suction box, which is preferably closed except for an air intake and an air outlet, that also comprises the suction fan for mounting below said hob.

[0043] Such a design greatly facilitates the use and installation of the device in accordance with the present invention.

[0044] In an embodiment of the device according to the invention, the device further comprises a guide element for guiding an upward or downward motion of the upper duct element and / or the lower duct element. In one particular further embodiment, said guide element can be located within said suction box and can be in fluid connection with said environment above said hob on one side and with said suction fan on the other side. At least one removable odour filter can be located in a fluid passage between said guide element and said suction fan, wherein preferably said suction box comprises at least one removable cover part, preferably a front cover, for accessing and removing / changing the odour filter.

[0045] In this way, the guide element can have a double function in that it 1) provides guidance for the duct elements and in that it 2) serves to hold said odour filter, which is particularly useful if said device is used as a recirculation (recycling) extractor.

[0046] In an embodiment of the device according to the invention the suction fan can be devised as a circumferential fan an impeller axis of which is oriented perpendicular with respect to a motion direction of the duct elements and preferably parallel to a back-front direction of the hob.

[0047] Applicant has found that such a design provides good suction efficiency and can help to further reduced space consumption below the hob.

[0048] In another embodiment of the device according to the invention the suction fan is located behind the duct elements with respect to a user side of the hob.

[0049] This helps to further reduce space requirement. If the fan is also located further down so that the above-described terminal protrusion extends above the fan, an obtainable suction area can be optimised.

[0050] The above-described positioning of the fan, i.e., a corresponding motor and blower or impeller perpendicular to the suction unit and not directly below it has the additional advantage of preventing that any overflowing of liquids from the hob through the suction duct can directly impact the blower and the fan motor.

[0051] In a corresponding further embodiment of the device according to the invention the upper duct element extends above the fan in a direction away from said user side of the hob. This preferably corresponds to said terminal protrusion that was mentioned earlier.

[0052] Further advantages and characteristics of the invention will become apparent from the appended drawings that show exemplary embodiments thereof. Figure 1 shows a hob extractor device including an induction hob with its suction duct in the first position; Figure 2 shows a first sectional view of the device in Figure 1; Figure 3 shows a second sectional view of the device in Figure 1; Figure 4 shows the device of Figure 1 with the suction unit in the intermediate position; Figure 5 shows a first sectional view of the device in Figure 4 together with a cooking vessel; Figure 6 shows a second sectional view of the device in Figure 4; Figure 7 shows the device of Figure 1 with the suction in the second position; Figure 8 shows a first sectional view of the device of Figure 7 together with two cooking vessels; Figure 9 shows a second sectional view of the device of Figure 7; Figure 10 shows a perspective view of the suction box in the hob extractor device without the hob; and Figure 11 shows a detailed perspective view of the upper duct element.

[0053] In all of the drawings, the same reference signs are used to indicated the same elements or elements that have at least similar functions.

[0054] In Figure 1, reference numeral 1 denotes the hob extractor device, which is a device that includes / combines a hob 2 (e.g., an induction hob, as shown) and a hob extractor 3 that is integrated with the hob 2. Figure 1 shows the hob extractor 3 in a default position that corresponds to a "level 1", as will be explained further down. Reference numeral 4 denotes a user control interface for controlling the hob extractor 3; separate user interfaces 5 are present for controlling the hob 2 and its different cooking zones.

[0055] Below hob 2 is located a two-part suction box 6 having a removable cover part 7, which suction box 6 holds various components of the hob extractor 3, as will become apparent later. By removing cover part 7, one can access these components for installation, replacement and / or maintenance.

[0056] In said default position of the hob extractor 3, a removable grid 8 that is located at an upper end of a suction duct (not visible in Figure 1) of the hob extractor 3 extends essentially flush with an upper surface 2a of the hob 2. Via said user control interface 4, the hob extractor 3 can be turned on and off and part of it can be raised with respect to the default position, as shown in Figures 4 ff.

[0057] The dimensions indicated in Figure 1 are only shown for information purposes; the invention is not limited in this respect.

[0058] With reference to Figure 2, it can be seen that the hob extractor device 1 comprises an opening 2b in said hob 2 and a suction fan 9 that is located below said hob 2 inside said suction box 6. A suction unit 10 is in operative fluid connection with an environment E above said hob 2 on one side and with said suction fan 9 on the other side. Said suction unit 10 is located in an area of said opening 2b and constitutes a suction duct for extracting cooking vapours produced by the hob 2 by means of said suction fan 9. For moving the suction unit 10 upwards and downwards with respect to (and through) said opening 2b, a lifting unit 11 is devised for moving the suction unit 10 between a first position, in which said grid 8 located at the upper end of said suction unit 10 is located at a first height, i.e., flush with respect to the hob 2 (i.e., said hob surface 2a), and a second position, in which said upper end of said suction unit 10 is located at a second height (cf. Figures 8-11) with respect to the hob 2, said second height being greater than said first height.

[0059] As can be further gathered from Figure 2, said suction unit 10 comprises two separate telescopic duct elements 10a, 10b of rectangular cross-section that together form said suction duct 10 and that are individually and / or jointly movable by said lifting unit 11. In this way said upper end of said suction unit 10 can be placed at said second position when both duct elements 10a, 10b are moved upwards. Furthermore, said upper end of said suction unit 10 can also be placed at an intermediate position between said first position and said second position when only one 10a of the duct elements 10a, 10b is moved upwards. These positions preferably correspond to the different levels mentioned further up, i.e., first position = level 1; second position = level 3; intermediate position = level 2. The lower duct element 10b is of a larger cross-section than the upper duct element 10a (or at least part thereof) so that said upper duct element 10a is (at least partly) inserted in said lower duct element 10b at level 1.

[0060] To achieve the above-mentioned movement, said lifting unit 11 comprises a motor means 12 that is devised in the form of an electric motor with a driven worm screw 13 forming part of a rotating screw jack. Said worm screw 13 engages a translating nut or threaded bushing 13a. Said threaded bushing 13a is attached to a (broadened) lower end of a (hollow) drive shaft 13b that has a circumferential shoulder 13c at an intermediate position in the direction of its upper end, which shoulder 13c supports said upper duct element 10a in the area of centre bridge element 10ac, which bridge element 10ac is integral with upper duct element 10a. Lower duct element 10b has an integral centre bridge element 10bb, too, which is however not formed straight (as bridge element 10ac) but has a trapezoidal shape, as can be gathered form the sectional view of Figure 2. The trapezoidal shape allows to achieve some kind of mechanical hysteresis when operating said lifting unit 11, as will become apparent later.

[0061] In Figures 2 and 3, the drive shaft 13b and the threaded bushing 13a are in a low (lowmost) position on the worm screw 13.

[0062] All the components of the lifting unit 11 can best be seen from Figure 9 which shows the completely expanded state of the system.

[0063] Alternatively, said lower duct element 10b could be mechanically coupled with said upper duct element 10a for subsequently moving first said upper duct element 10a and then - when said upper duct element 10a has reached a predetermined position - also said lower duct element 10b, which is also equivalent to some kind of mechanical hysteresis.

[0064] As can be seen from Figures 2 and 3, the two duct elements 10a, 10b are slidable in the upwards and downwards direction within a guide element 14 that forms (an integral) part of said suction box 6 and that extends downwards with respect to the suction unit 10. Preferably, the motor means 12 are fixed to a bottom wall of guide element 14. Guide element 14 further has lateral openings 14a at which are located removeable odour filters 15 that are arranged in an air flow path from the environment E through suction unit 10 towards suction fan 9 (cf. also Figure 12).

[0065] As can be further seen from Figure 3, the upper duct element 10a has lateral openings 10aa and a terminal protrusion 10ab that extends, in the backward direction, i.e., away from a user side of the hob extractor device 1 and essentially in parallel with said upper surface 2a of the hob 2 (or a plane of the hob 2) over a space in which is located said suction fan 9. Said terminal protrusion 10ab forms a part of the upper duct element 10a that is not inserted / insertable in lower duct element 10b. The lateral openings 10aa also extend in a region of said terminal protrusion 10ab, and so is the grid 8. Thus, the total available suction area is increased - already in the shown first position (= level 1).

[0066] Figure 4 shows the hob extractor device 1 with the suction unit 10 in its intermediate position (= level 2), in which only the upper duct element 10a has been raised, thus exposing said terminal protrusion 10ab and all of the lateral openings 10aa.

[0067] As illustrated in Figure 5, a height of the upper end (i.e., said grid 8) above the hob surface 2a preferably is between 60 and 65 mm, without limitation. As previously stated, only the upper duct element 10a has been raised. This is sufficient to draw in vapours from lower cooking vessels or pans, such as illustrated at reference numeral 16.

[0068] Reference numeral 17 denotes a removeable (and preferably washable) grease filter that is located within the upper duct element 10a and that can be taken out from the suction unit 10 after having removed the grid 8.

[0069] Figure 6 shows the hob extractor device 1 of Figures 4 and 5 in a different view from a reverse angle for enhanced intelligibility. Worm screw 13 has been rotated by motor means 12, e.g., in clockwise direction, thus moving threaded bushing or translating nut 13a upwards together with drive shaft 13b, said shoulder 13c of which in turn pushes upwards bridge element 10ac of upper duct element 10a, thus achieving said level 2.

[0070] Referring now to Figure 7, the hob extractor device 1 is shown with the suction unit 10 in its second (or highest) position (=level 3), wherein both duct elements 10a, 10b have been (completely) moved upwards by means of the lifting unit 11.

[0071] As illustrated in Figure 8, a height of the upper end (i.e., said grid 8) above hob surface 2a preferably is between 130 and 150 mm, without limitation. Both the upper duct element 10a and the lower duct element 10b have been raised to achieve this. Such an arrangement is preferred in order to draw in vapours from lower cooking vessels or pans, such as illustrated at reference numeral 16, and from higher cooking vessels or pots, such as illustrated at reference numeral 18.

[0072] Figure 9 shows a similar view as in Figure 6, only for the case in which both duct elements 10a, 10b have been raised. Worm screw 13 has been further rotated by motor means 12 in clockwise direction thus moving threaded bushing or translating nut 13a further upwards together with drive shaft 13b, the shoulder 13c of which further pushes upwards bridge element 10ac of upper duct element 10a, thus achieving said level 3. At the same time, since threaded bushing 13a has made contact with bridge element 10bb of lower duct element 10b from below (cf. Figure 6), lower duct element 10b is also moved upwards in synchronicity with upper duct element 10c.

[0073] The telescopic duct system closes through the, e.g., counterclockwise rotation of the worm screw 13 by the motor means 12 that makes the threaded bushing 13a and the drive shaft 13b move down. By gravity, both the upper and lower part of the telescopic system, i.e., the upper and lower duct elements 10a, 10b are then also lowered to reach the closing position of the telescopic system wherein the cover grid 8 flush with the hob surface 2a (cf. Figures 1-3).

[0074] Figure 10 is a perspective view and shows the suction box 6 of the hob extractor device 1 (cf. the previous Figures) without the hob 2. As can be gathered from said drawing, the suction box 6 is composed of two parts, one being the above-mentioned front or cover part 7 that is attached by screws 19 to a rear part 20, said rear part 20 encasing the suction fan 9, which is a centrifugal fan (impeller axis oriented perpendicular to the motion direction of the duct elements and in front-back direction). The front part 7 is shallower than the rear part 20 and of trapezoidal cross-section (cf. also Figure 1). It integrally comprises said guiding element 14, which has front and back protrusions 14b that engage complementary grooves 10ba of lower duct element 10b (the upper duct element is not shown in Figure 12).

[0075] The arrows AF in Figure 12 illustrate air flow through the above-mentioned odour filters 15 towards suction fan 9.

[0076] Figure 13 shows details of the upper end of suction unit 10 with the upper duct element 10a in the intermediate position (= level 2). As can be gathered from said drawing, the upper duct element 10a preferably comprises two lighting elements (e.g., LED elements or LED bars) 21 on the inside in an area between the grid 8 and the lateral openings 10aa.

Claims

1. A hob extractor device (1), comprising: a hob (2) having at least one opening (2b); a suction fan (9) that is preferably located below said hob (2); a suction unit (10) in operative fluid connection with an environment (E) above said hob (2) on one side and with said suction fan (9) on the other side, which suction unit (10) is located in an area of said opening (2b) and constitutes a suction duct for extracting cooking vapours by means of said suction fan (9); a lifting unit (11) for moving the suction unit (10) upwards and downwards with respect to said opening (2b) between a first position, in which an upper end of said suction unit (10) is located at a first height with respect to the hob (2), and a second position, in which said upper end of said suction unit (10) is located at a second height with respect to the hob (2), said second height being greater than said first height; characterised in that said suction unit (10) comprises at least two separate duct elements (10a, 10b) that together form said suction duct and that are individually and / or jointly movable by said lifting unit (11) for placing said upper end of said suction unit (10) at said second position when both duct elements (10a, 10b) are moved upwards and for placing said upper end of said suction unit (10) at an intermediate position between said first position and said second position when only one of the duct elements (10a, 10b) is moved upwards.

2. The device (1) of claim 1, wherein said first height corresponds to a level of an upper surface (2a) of the hob (2).

3. The device (1) of claim 1 or 2, wherein said second height is 100 to 150 mm and said intermediate height is 60-65 mm above an upper surface (2a) of the hob (2), respectively.

4. The device (1) of any one of claims 1 to 3, wherein the duct elements (10a, 10b) are telescopically inserted into each other and can be moved individually with respect to the hub (2).

5. The device (1) of any one of claims 1 to 4, wherein the duct elements (10a, 10b) are of rectangular cross-section.

6. The device (1) of any one of claims 1 to 5, wherein one of the duct elements is a lower duct element (10b) with larger cross-section and the other one of the duct elements is an upper duct element (10a) with smaller cross-section and is inserted into said lower duct element (10b).

7. The device (1) of claim 6, wherein said upper duct element (10a) has a removable grid (8).

8. The device (1) of claim 6 or 7, wherein a removable grease filter (17) is located inside said upper duct element (10a).

9. The device (1) of any one of claims 6 to 8, wherein said upper duct element (10a) has a terminal protrusion (10ab) with respect to the lower duct element (10b) essentially in parallel with a plane of said hob (2).

10. The device (1) of any one of claims 6 to 9, wherein said upper duct element (10a) has lateral openings (10aa) for a passage of cooking vapours.

11. The device (1) of any one of claims 1 to 10, wherein said lifting unit (11) comprises a motor means (12) that is coupled to at least one of said duct elements (10a, 10b).

12. The device (1) of claim 11, wherein said motor means (12) is devised in the form of an electric motor with a worm screw (13), wherein, with reference to any one of claims 6 to 10, said worm screw (13) is mechanically coupled, e.g., by means of drive shaft (13b) having a shoulder (13c), at least with said upper duct element (10a) and wherein either a) said worm screw (13) is further coupled with said lower duct element (10b), e.g., by means of a translating nut (13a) that is fixed to said drive shaft (13b), for subsequently moving said upper duct element (10a) and said lower duct element (10b) or b) said lower duct element (10b) is mechanically coupled with said upper duct element (10a) for subsequently moving said upper duct element (10a) and said lower duct element (10b).

13. The device (1) of claim 11, wherein said motor means (12) is devised in the form of an hydraulic piston driven by an electric motor wherein, with reference to any one of claims 6 to 10, a piston element is mechanically coupled at least with said upper duct element (10a) and wherein either a) said piston is further coupled with said lower duct (10b) element for subsequently moving said upper duct element (10a) and said lower duct element (10b) or b) said lower duct element (10b) is mechanically coupled with said upper duct element (10a) for subsequently moving said upper duct element (10a) and said lower duct element (10b).

14. The device (1) of any one of claims 1 to 13, wherein said suction unit (10) and said lifting unit (11) are placed in a suction box (6) that also comprises the suction fan (9) for mounting below said hob (2).

15. The device (1) of any one of claims 1 to 14, further comprising a guide element (14) for guiding a upward or downward motion of the upper duct element (10a) and / or the lower duct element (10b), said guide element (14) being located, with reference to claim 14, within said suction box (6) and being in fluid connection with said environment (E) above said hob (2) on one side and with said suction fan (9) on the other side, wherein at least one removable odour filter (15) is located in a fluid passage between said guide element (14) and said suction fan (9), wherein preferably said suction box (6) comprises at least one removable cover part (7).

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