AIR DUCT

Description

[0001] The invention relates to an arrangement comprising an air duct and a functional element mounted in the air duct. The air duct extends substantially in a longitudinal direction and has a duct wall enclosing a flow cross-section, which has a fastening device on its inner side, which has at least one linear rail extending at least partially in the duct's longitudinal direction and at least two undercut locking sections. The functional element can be pushed onto the fastening device in the duct's longitudinal direction. Such an arrangement is already known from DE 10 2017 221 725 A1.

[0002] Various types of air ducts for the ventilation of buildings are known from the state of the art. The purpose of an air duct, for example, is to remove the vapors generated during work in kitchens, especially when heating food and liquids, from the kitchen area, keeping the work area free of odors and condensate.

[0003] Against the backdrop of growing environmental awareness and increasing competitive pressure in a globalized economy, the goal of resource-efficient air duct production is, on the one hand, to reduce material usage and, on the other, to design the air ducts for the widest possible range of applications. Another air duct, for example, is known from DE 10 2017 104 772 A1.

[0004] However, the air ducts known from the prior art have the disadvantage that the insertion of the functional element to be accommodated in the air duct is laborious or difficult to handle. It is therefore the object of the invention to provide an air duct in which different functional elements can be accommodated in a particularly simple manner.

[0005] The problem is solved by an arrangement having the features of independent claim 1.

[0006] Accordingly, it is provided that the functional element has two locking feet which engage behind the undercut locking sections for fastening the functional element in the air duct. The air duct can in particular be designed as a flat duct. The flat duct can have a transverse dimension which is greater than a height dimension of the flat duct. As a result, the duct wall enclosing the flat duct can have a total of four wall sections, of which the wall sections extending in the transverse direction are parallel to one another and the wall sections extending in the vertical direction are parallel to one another. The wall sections can each merge into one another via rounded corners. Alternatively, the air duct can be designed as a round duct. The inner side of the duct wall faces in particular the flow cross-section. The functional element can be an element that technically interacts with the air duct.The functional element can also be an element that expands the technical function of the air duct. A suitable functional element can be, for example, a support bar, cable duct, or sound-damping element, or a combination thereof. The air duct can also have two oppositely arranged fastening devices. This allows a functional element accommodated in the duct to be fixed to opposite inner sides of the duct. The opposing fastening devices can, in particular, be arranged in alignment with one another.

[0007] It can be provided that the duct wall has a wall thickness that varies along its length. For example, in the case of a flat duct, it can be provided that the wall thickness is less in the rounded corners than in the straight wall sections. Furthermore, it can be provided that the wall thickness in the straight wall sections increases gradually towards the middle. In the case of a flat duct design, it can further be provided that the maximum thickness of the wall sections running in the transverse direction is greater than the maximum thickness of the wall sections running in the vertical direction. The wall thickness in the rounded corners can be, for example, between 0.8 and 1.6 mm, preferably between 1.0 and 1.4 mm, particularly preferably 1.2 mm. The maximum wall thickness of the wall sections running in the vertical direction can be, for example, between 1.0 and 1.5 mm, preferably between 1.2 and 1.3 mm, particularly preferably 1.25 mm.The maximum wall thickness of the wall sections running in the transverse direction can be, for example, between 1.5-2.1 mm, preferably between 1.7-1.9 mm, particularly preferably 1.8 mm. Starting from the point of maximum wall thickness in the middle of the wall sections running in the transverse direction, the corresponding wall sections on the outside of the flat duct can each extend towards the corners at an inclination of between 0.2-0.6°, preferably between 0.3-0.5°, particularly preferably 0.4°. The vertical extent of the flat duct can be, for example, 80-92 mm, preferably 84-88, particularly preferably 86.6 mm. The transverse extent of the flat duct can be, for example, 200-240 mm, preferably 210-230 mm, particularly preferably 219.6 mm. The inner radius of the rounded corners can be, for example, 15-25 mm, preferably 18-22 mm, particularly preferably 20 mm.

[0008] The air duct can also have a riblet structure on its inside. This can particularly advantageously reduce frictional resistance on surfaces subject to turbulent flow. The riblets can be designed as fine ribs with sharp tips. The longitudinal axes of the riblets or ribs can be aligned in the direction of flow.

[0009] It can further be provided that the air duct has stiffening ribs running longitudinally on its outer side. The spacing of the stiffening ribs can be smaller in the region of the rounded corners than in the region of the straight wall sections. The spacing of the stiffening ribs can gradually decrease towards the center of the straight wall sections. For example, the maximum spacing of the stiffening ribs on the transversely oriented wall sections of the flat duct can be between 5-15 mm, preferably between 8-12 mm, particularly preferably 10 mm. Furthermore, the maximum spacing of the stiffening ribs on the vertically oriented wall sections of the flat duct can be between 3-7 mm, preferably between 4-6 mm, particularly preferably 5 mm.

[0010] In the flat duct design with a substantially rectangular flow cross-section, the fastening device can preferably be arranged on the inside of one of the longer wall sections, in particular the transverse walls. When using the fastening device to attach a support web, the flat duct can be particularly advantageously supported at its structurally weakest point by the support web being supported against the opposite wall.

[0011] The fastening device can be designed to prevent movement of the functional element from the duct wall section having the fastening device toward the interior of the duct. This prevents slipping or displacement of the functional element along the vertical axis, particularly toward the center of the duct or the opposite wall of the air duct. For this purpose, the fastening device can comprise a holding device that can be gripped behind by a functional element inserted into the air duct.

[0012] The fastening device can further be designed to prevent movement of the functional element in a transverse direction of the duct wall section comprising the fastening device. This prevents slipping or displacement of the functional element along the transverse axis of the air duct, in particular along the duct wall section comprising the fastening device. For this purpose, the fastening device can comprise a holding device that laterally supports a functional element inserted into the air duct. In particular, the fastening device can comprise a holding device that fixes a functional element inserted into the air duct in the transverse direction from both sides.

[0013] Furthermore, the fastening device can be designed to prevent rotation of the functional element about a rotation axis perpendicular to the plane of the duct wall section having the fastening device. This prevents rotation of the functional element in or parallel to the plane of the duct wall section having the fastening device. For this purpose, the fastening device can have a holding device that supports a functional element inserted into the air duct in the transverse direction from both sides, with the support points being offset from one another in the longitudinal direction of the duct.

[0014] Furthermore, the fastening device can be designed to prevent rotation of the functional element about a rotation axis perpendicular to the flow cross-section. This can prevent rotation of the functional element parallel to the duct wall. For this purpose, the fastening device can comprise a holding device that can be engaged behind by a functional element inserted into the air duct at at least two support points spaced apart from one another in the transverse direction.

[0015] The fastening device can be designed to prevent rotation of the functional element about a rotation axis perpendicular to the longitudinal section of the duct. This can prevent rotation of the functional element about the transverse axis. For this purpose, the fastening device can comprise a holding device that can be gripped behind by a functional element inserted into the air duct at at least two support points spaced apart from one another in the longitudinal direction.

[0016] Furthermore, the fastening device can comprise at least one linear rail extending at least partially in the longitudinal direction of the channel. In particular, the linear rail can be arranged centrally on the channel wall having it. The linear rail can extend over the entire length of the channel.

[0017] For example, the at least one linear rail can have a longitudinal groove in which the two locking sections are formed with an undercut facing one another. Alternatively, the at least one linear rail can have two locking sections facing away from one another on its outer sides in the transverse direction.

[0018] The fastening device can comprise two parallel linear rails, each of which has an undercut locking section. To simplify threading the functional element, the two linear rails can have a widened portion at the longitudinal ends of the channel piece or can be slightly spaced apart from each other. The locking sections at the widened ends can also be widened accordingly.

[0019] The at least one linear rail can have a first section extending substantially perpendicularly away from the channel wall and a second section adjoining thereto and extending substantially parallel to the channel wall.

[0020] The undercut locking sections can point toward each other. Alternatively, the undercut locking sections can point away from each other.

[0021] The fastening device can be formed integrally with the channel wall or molded onto it. The channel can be manufactured, for example, by extrusion.

[0022] It can be provided that the air duct is designed as a flat duct and has a varying wall thickness, wherein the wall thickness is smaller in the corner areas than in the straight wall sections, and wherein the wall thickness increases towards the middle of the straight wall sections.

[0023] To install the functional element, it can be pushed over one of the end faces of the air duct onto the fastening device, which is open at the end faces. The locking feet can be connected to each other via two locking legs. When installed, the locking legs can be slightly pre-tensioned in the locking sections. This ensures secure fastening of the functional element in the air duct.

[0024] Furthermore, it can be provided that the functional element has a support element which supports the air duct and extends between the fastening device and the duct wall section opposite the fastening device. It can be provided that the support element slightly prestresses the opposite supported duct walls against one another. If the air duct has two opposite fastening devices, the support element can be inserted into the respective fastening device with opposite locking feet. If only one fastening device is provided in the flat duct, the support element can be designed such that it has a force introduction surface on its side opposite the fastening device. The force introduction surface can in particular be designed parallel to the duct wall adjacent to it, so that the force introduction surface lies flat against the duct wall assigned to it.The provision of a force introduction surface results in improved support and tilt protection of the support element, whereby the support element is supported according to Euler's third buckling case and thus has a higher critical buckling load. Furthermore, the support element can be designed as a support web with a web section extending essentially parallel to the vertical extent of the channel. The web section can have a thickening toward the center of the web, where the highest stresses can occur. The center of the web can have a thickness of 1.9-2.1 mm, preferably 1.95-2.05 mm, particularly preferably 1.99 mm.

[0025] In addition, the functional element can have a cover extending between the undercut locking sections, by means of which cover a cable duct is formed between the cover and the duct wall section covered by this cover, which extends in the longitudinal direction of the duct and is separated from the flow region. The cable duct can be designed in such a way that, for example, a compressed air hose with a diameter of 8 mm and a 4x6 mm cable can be accommodated in it simultaneously. The cover can extend between the two locking feet and / or be molded onto them. The cover can in particular be semicircular. Furthermore, the cover and the support web can be designed as a combination. In this case, the support web can extend away from the cover above the latter. The support web can be molded onto the cover.Due to the semicircular cover, this, in combination with the support element, provides particularly good stress distribution. Directly above the cover, the web can have a thickness between 1.2-1.4 mm, preferably 1.25-1.35 mm, particularly preferably 1.28 mm. Directly below the force introduction surface, the web can have a thickness between 1.15-1.35 mm, preferably 1.2-1.3 mm, particularly preferably 1.23 mm.

[0026] The surfaces of the functional elements assigned to the flow areas of the air duct can each be covered with a riblet structure.

[0027] Further properties, advantages and features of the invention can be seen in the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of an embodiment of a flat duct according to the invention; Fig. 2 is a perspective view of an embodiment of a round duct according to the invention; Fig. 3a is a cross-sectional view of an embodiment of a flat duct according to the invention with a fastening device; Fig. 3b is a cross-sectional view of an embodiment of a flat duct according to the invention with two opposing fastening devices; Fig. 4a is a perspective view of a support web-cable duct combination according to the invention; Fig. 4b is a cross-sectional view of a support web-cable duct combination according to the invention; Fig. 5a is a perspective view of a cable duct; Fig. 5b is a cross-sectional view of a cable duct; Fig. 6 is a cross-sectional view of a functional element inserted into a flat duct.

[0028] Figure 1shows a first embodiment of the air duct 301 in the form of a flat duct 316. This extends essentially in a longitudinal direction X, which corresponds to the flow direction, in a transverse direction Y and in a vertical direction Z, wherein the horizontal wall sections oriented in the transverse direction Y are longer than the vertical wall sections oriented in the vertical direction Z. The four wall sections shown together form the duct wall 302 enclosing the flow cross-section lying in the YZ plane, wherein the corner regions of the adjacent duct wall sections are each rounded. Centrally in the duct interior 306 on the lower horizontal duct wall, in the duct wall section 305, a fastening device 303 is arranged, which has two parallel linear rails 307 with mutually facing locking sections 308, wherein the locking sections 308 are designed with an undercut relative to the duct interior 306.The parallel linear rails 307 extend in the longitudinal direction X of the flat channel 316. It can be seen that a rib structure 315, so-called riblets, is arranged on the channel wall 302 in the channel interior 306, covering the walls. The ribs extend in the longitudinal direction X of the flat channel 316. The fine ribs 315 prevent transverse movements of the vortices in the turbulent flow prevailing in the flat channel and thereby minimize friction losses at the walls. On the outer sides of the channel walls 302, it can also be seen that stiffening ribs 318 are arranged in the longitudinal direction X of the channel 301, thereby increasing the torsional rigidity of the channel. As can be seen, the stiffening ribs 318 in the corner areas of the channel 301 have a smaller spacing than on the straight wall sections, with the spacing of the stiffening ribs 318 additionally decreasing towards the center of the straight wall sections.

[0029] Figure 2shows a second embodiment of the air duct 301 in the form of a round tube 317. The duct wall 302 enclosing the round flow cross-section has on its inside on a duct wall section 305 a fastening device 303 which, like the one in Figure 1 The embodiment shown has two parallel linear rails 307, which have mutually facing locking sections 308. The inside of the round tube is also lined with riblets 315.

[0030] The Figure 3a and 3b each show cross-sectional views of a flat channel 316, wherein the Figure 3a shown embodiment a fastening device 303 and the one in Figure 3bThe embodiment shown has two opposing fastening devices 303. As can be seen, the flat channel 316 has a varying wall thickness, the wall thickness being less in the corner regions than in the straight wall sections, the wall thickness increasing towards the middle of the straight wall sections. As a result, the outer side of the straight wall sections has a slight gradient towards their middle. It can be seen that riblets 315 running in the longitudinal direction X are arranged in the channel interior 306, distributed over the entire flow cross-section. Furthermore, stiffening ribs 318 running in the longitudinal direction X are arranged on the outer side of the wall 302 of the channel 316.The fastening device 303 arranged at the bottom of the flat duct 316 has two opposing linear rails 307, each linear rail 307 having a locking section 308 aligned parallel to the lower wall section, the two locking sections 308 of the parallel linear rails 307 facing one another. The locking sections 308 are each connected to the lower duct wall section at a distance from it via a substantially vertically arranged first section. Below the locking sections 308, the linear rails 307 have guide grooves in the longitudinal direction X in the wall section assigned to them, which serve as additional linear guides for the respective functional element used. Between the linear rails 307, the duct wall also has riblets 315 on its inside for when the air duct is used without a functional element and the relevant surface is exposed. In . Figure 3bIt can be seen that the wall sections 305 of the uniformly formed fastening devices 303, which are opposite one another in the height direction Z, are aligned in the transverse direction Y.

[0031] Figure 4shows a functional element 304 that can be mounted in the air duct 301, which is designed in the form of a combination of a support element 311 with a cover 313. For fastening the functional element 304, this has locking feet 310, which can be inserted into the locking sections 308 of the fastening device 303 and engage behind them. As a result, the functional element is displaceable in the longitudinal direction X of the air duct 301 and is restricted in all other degrees of freedom. The locking feet 310 are connected to the support section 320 of the support element 311 via locking legs, wherein the locking legs are curved in a semicircle, so that a separate cavity is formed underneath, separated from the flow cross-section, which can be used as a cable duct 314. As in Figure 4bAs can be seen, the thickness of the support section 320 increases toward the center and is, in comparison, smaller in the area of the connection points to the locking legs or cover 313 and to the force introduction surface 319 on the upper side of the support element. The force introduction surface 319 adjoins the upper end of the support section 320 in a T-shape and projects laterally. The outer surfaces of the functional element 304, i.e., the surfaces facing the flow channel, are covered with riblets 315.

[0032] In Figure 5a the functional element 304 is shown in perspective as a cover 313, in Figure 5bas a cross-sectional view. When inserted into the air duct 301, a cable duct 314 is formed beneath the cover, extending in the longitudinal direction X. As can be seen, the cover has a semicircular, dome-shaped contour, although other cross-sections are also conceivable. At the lower ends of the semicircle or the locking legs, the locking feet 310 extend horizontally and in opposite directions. The surface of the cover 313 is covered with riblets 315.

[0033] An arrangement 309 comprising a flat channel 316 and a functional element 304 accommodated therein is shown in Figure 6 The recorded functional element 304 in this case is the Figure 4shown support web-cable duct combination, which serves on the one hand to support the flat duct in its vertical direction Z and on the other hand to provide a cable duct 314. For assembly, the functional element 304 is pushed into the flat duct 316 from one of the end faces in the longitudinal direction, wherein the locking feet 310 of the functional element 304 are threaded into the locking sections 308 of the linear rails 307. The locking legs are pressed together, since they are inserted into the fastening device 303 under slight pretension for better fixing. It can be seen that the undersides of the locking feet are guided in the longitudinal grooves formed in the duct wall adjacent to them. On the duct wall section 312 opposite the fastening device, the support element 311 supports the opposite duct wall by means of the force introduction surface 319 adjacent to it.A cable duct 314 is formed between the cover 313 and the duct wall section 305 covered by the cover 313 and having the fastening device 303, which is fluidically separated from the flow channel of the air duct.

[0034] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the realization of the invention both individually and in any combination. Reference symbol list

[0035] 301Air duct 302Duct wall 303Fastening device 304Functional element 305Duct wall section 306Duct interior 307Linear rail 308Locking section 309Arrangement 310Locking foot 311Support element 312Opposite duct wall section 313Cover 314Cable duct 315Riblets 316Flat duct 317Round duct 318Stiffening ribs 319Force introduction surface 320Support section XLongitudinal direction YTransverse direction ZHeight direction

Claims

1. Arrangement (309) comprising an air duct (301) and a functional element (304) mounted in the air duct (301), wherein the air duct (301) extends substantially in a longitudinal direction (X) and has a duct wall (302) which encloses a flow cross section and which has on its inner side at least one fastening device (303) which has at least one linear rail (307) which extends at least in sections in the duct longitudinal direction (X), and at least two undercut latching sections (308), wherein the functional element (304) can be pushed onto the fastening device (303) in the duct longitudinal direction (X), characterized in that the functional element (304) has two latching feet (310) which engage behind the undercut latching sections (308) in order to fasten the functional element (304) in the air duct (301).

2. Arrangement (309) according to claim 1 or 2, wherein the fastening device (303) comprises two parallel linear rails (307), each of which has an undercut latching section (308).

3. Arrangement (309) according to one of the preceding claims, wherein the undercut latching sections (308) point towards one another or point away from one another.

4. Arrangement (309) according to one of the preceding claims, wherein the fastening device (303) is formed in one piece with the duct wall (302) or is integrally formed thereon.

5. Arrangement (309) according to one of the preceding claims, in which the air duct (301) is designed as a flat duct (316) and has a varying wall thickness, wherein the wall thickness is smaller in the corner regions than in the straight wall sections, and wherein the wall thickness increases towards the centre of the straight wall sections.

6. Arrangement (309) according to one of the preceding claims, wherein the functional element (304) has a supporting element (311) which supports the air duct (301) and which extends between the fastening device (303) and the duct wall section (312) opposite the fastening device (303).

7. Arrangement (309) according to claim 6, wherein the thickness of the supporting element (311) increases towards the centre of the duct and is smaller in comparison in the region of the duct walls.

8. Arrangement (309) according to one of the preceding claims, wherein the functional element (304) has a cover (313) which extends between the undercut latching sections (308) and by means of which a cable duct (314) which is separated from the flow region and extends in the duct longitudinal direction (X) is formed between the cover (313) and the duct wall section (305) covered thereby.