EP1507126B1 - Fin and gas heating device comprising a plurality of said fins - Google Patents

Description

The invention relates to a lamella and a device for heating gas streams, in particular for heating interiors, such as motor vehicles, for heating the intake air of engines or the like, with at least one substantially tubular heating unit with a plurality of such arranged on the heating unit fins for heat dissipation to the gas to be heated, in particular air.

For heating the passenger compartment of motor vehicles, it is known to use the waste heat of the drive motor using exhaust gas heat exchangers. The disadvantage here is that especially at low ambient temperatures, the warming of the interior or the passenger compartment occurs only after a significant delay after several minutes, which is extremely unpleasant for the occupants. In addition, modern engines have a higher efficiency, so that they produce less waste heat, which is no longer sufficient for heating the interior of the motor vehicle at high temperatures.

The DE 198 48 169 A1 describes a generic device for heating of interiors, especially of motor vehicles. The device has a plurality of heat dissipation to the gas to be heated lamellae, which sit in a parallel arrangement on a heated heating unit in the form of one or more parallel profile tubes, in particular square tubes, clamping, wherein the square tubes or each one or enforce several recesses of the slats. For improved heat transfer between the square tubes and the slats is provided to bend the square tubes facing edges of the openings of the slats to form standing in contact with the tubes tabs of the slat plane out. Further, the lamellae are at their serving for heat emission to the gas to be heated areas, which extend radially in the longitudinal direction of the lamellae away from the tubes or between them, equipped with bent out of the lamellar plane clamping lugs, which elastically to the respective adjacent lamella for conditioning reach and thus stabilize the arrangement of a plurality of slats side by side. Finally, the slats - viewed in the longitudinal direction of the same direction - laterally of the apertures arranged and extending in the longitudinal direction of the slats beads, which stabilize the clamping seat of the slats on the square tubes.

Due to the clamping seat of the lamellae on the profile tubes dimensional changes occurring in temperature changes of both the fins and the tubes can be compensated, so that a more durable and against vibration stable seating of the lamellae is ensured while ensuring a constant transfer of heat between the square tube and the lamellae.

Although such a heating element due to its independence from the heat of the drive motor relatively quickly to a warming of the passenger compartment and is ensured even in vehicles with modern engines with high efficiency permanent heating of the passenger compartment even at low ambient temperatures. However, the lamellae of the known device on the one hand have a relatively poor dimensional stability, which in particular in the case of vibrations, as inevitably occur during operation of a motor vehicle, leads to undesirable noise and also entails manufacturing problems, the lamellae entails e.g. bent on the occasion of the punching process and incurred as a committee. On the other hand, in particular, the heat transfer of the slats has proven to be in need of improvement, which is primarily related to the fact that the gas flow to be heated passes the available heat exchange surface of the slats relatively quickly. Moreover, especially in the case of superficial unevenness of the profile tubes, it may happen that the tabs in contact therewith, located at the edges of the apertures of the laminations, are only partially, e.g. only punctually, abut the profile tubes, so that there is also an insufficient heat transfer.

Another device for indoor heating is also in US 4 984 626 A disclosed.

Based on this prior art, the present invention seeks to provide in a device of the type mentioned above or at a lamella of such a device for improved heat transfer and at the same time for increased dimensional stability of the slats.

According to the invention, this object is achieved in a device of the type mentioned above in that the lamellae are provided with embossments which protrude from the lamellar plane.

To solve this problem, the invention further provides for a lamella for such a heater, that it is provided with embossments, which protrude from the lamellar plane.

On the one hand, a considerably improved heat transfer to the gas to be heated, in particular air, is ensured on the one hand by the embossings enlarging the heat exchange surface on the one hand, and on the other hand by generating local turbulences of the gas flow to be heated the heat transfer are favorable. In this case, it is also possible in particular to achieve a turbulent flow in the case of an inflow velocity, which leads to laminar flow in a conventional planar formation of the lamellae, so that the formation of a substantially constant temperature gradient of the gas flow in the region of the surface of the lamellae is prevented and the temperature difference between the fin and the gas flow, which drives the heat transfer, is increased as a result of the turbulence in the area of the fin surface. At the same time, the swirling of the gas stream also increases its contact time with the lamella surface and thus the residence time available for heat transfer. Moreover, it is possible by appropriate arrangement of the embossments to provide for a respective desired line or deflection of the gas stream to be heated, which is particularly advantageous in the case of the use of the heater in motor vehicles, which by design usually have air ducts with multiple curvatures. Furthermore, the embossings of the blade according to the invention give increased dimensional stability, so that on the one hand noises of the heating device, as can occur under the action of vibrations, are reliably prevented. This applies both to the use of the device according to the invention for heating the passenger compartment of motor vehicles as well as in the case of their use for preheating the intake air of internal combustion engines, as it is carried out primarily in diesel engines. On the other hand, bending of the slats in the production or in the further processing, for example, during the punching process, avoided, so that an effective mass production is ensured with the greatest possible avoidance of rejects.

With "embossing" of the slats in the context of the invention, moreover, only such deformations of the generally planar slat plane are addressed, which do not enforce the slat plane, i. In any case, there are no apertures or holes passing through the lamellae plane in the region of the embossments which could impair the dimensional stability of the lamellae. The embossing of the lamellae according to the invention are consequently arranged exclusively on the lamellae while maintaining an unbroken surface. Such embossing while maintaining an uninterrupted lamellar plane have also proved to be favorable, especially for reasons of better heat conduction within the lamellae of their standing with the tubular heating unit in heat-conducting contact areas up to the peripheral region of the fins.

In an expedient embodiment, the embossings are at least at the region of the lamellae serving for heat emission to the gas to be heated, which extends in the longitudinal direction of the lamellae extends substantially radially away from the at least one tube, arranged to provide there for a proper heat transfer to the gas to be heated.

The lamellae according to the invention are arranged in a clamping manner on the outside of the tube, as is known from the cited above DE 198 48 169 A1 is known.

According to the invention, a plurality of lamellae arranged one behind the other in the flow direction of the gas to be heated are provided, wherein rows of imprints of the lamellae arranged one behind the other are provided. These embossments arranged in rows are arranged offset in the flow direction of the gas to be heated. On the one hand, such a configuration of the lamellae can be produced simply and inexpensively; on the other hand, a large number of turbulences of the lamellae sweeping gas stream and, in particular, turbulence can be achieved, which, as already mentioned, improves the heat transfer of the lamellae to the gas stream and improves the lamination Heat conduction within the gas stream is favorable.

In order to further improve the heat transfer between the embossing of the lamellae and the gas stream to be heated, the invention provides that the embossments of the lamellae have a steep rise in the direction of flow of the gas to be heated and a drop which is relatively shallower. In this way, a kind of stagnation point of the inflowing gas and thus be generated in an effective manner turbulence. While the angle of increase of the embossments with respect to the fin surface preferably between about 45 ° and about 90 °, in particular between about 60 ° and about 90 °, for example between may be about 70 ° and about 90 °, the angle of decrease of the imprints against the fin surface may preferably be between about 1 ° and about 45 °, more preferably between about 1 ° and about 30 °, eg between about 5 ° and about 20 ° , amount.

The invention provides that the embossments of the slats are square, in particular substantially trapezoidal or rectangular, are formed.

Another embodiment, which is not part of the invention, provides that the embossments of the slats are formed substantially V-shaped, wherein the tip of the "V" of the substantially V-shaped embossing of the slats with advantage against the inflowing, to can be arranged heating gas. On the one hand, turbulences of the gas flow can be generated by louvers of such a design; on the other hand, the V-shaped embossments in the lamellar plane act in the manner of baffles, so that the inflowing gas is deflected outwards along its legs along the legs of the "V" and the contact time of the Gas flow is increased at the surface of the fins.

The limbs of the "V" of the substantially V-shaped embossing of the lamellae can either have an approximately linear extension direction or an approximately circular or elliptical segment-shaped extension direction, wherein they advantageously have a convex curvature, viewed in the last-mentioned alternative, from the inflow direction of the gas to divert the gas flow in such a way that the longest possible contact time results with the lamellar surface.

In this alternative embodiment, a plurality of V-shaped embossments of the lamellae are preferably arranged one behind the other in the flow direction of the gas to be heated, wherein the opening angle of the "V" of the V-shaped embossments of the lamellae can be of different sizes. In this case, it may further be provided that the opening angle of the "V" of the V-shaped embossments of the lamellae arranged one behind the other in the flow direction of the gas to be heated increases in the flow direction of the gas, so that each of the V-shaped embossments for a further deflection of the Gas stream and thus at the same time for effective turbulence of the same provides.

To solve the problem underlying the invention, the invention provides in a generic device in which the lamellae are arranged clampingly on the outside of the tube, further, that the lamellae have at least one opening formed as a profile tube tube breakthrough and at least two opposite edges the openings are bent to form lugs bent out of the lamellar plane, the opposite edges being interrupted by slots arranged substantially perpendicularly to the opening, so that a plurality of lugs arranged side by side in the direction of extension of the edges are formed. By such a configuration, not only the heat transfer of the fins to the gas to be heated, but in particular, the heat transfer of the heated profile tubes to the slats improved by the plurality of spaced by slots tabs, which are clamped on the outside of the profile tubes, have the largest possible contact area with the heated profile tube. In particular, this also surface unevenness of the profile tubes are compensated, since the juxtaposed straps are on the one hand in comparison with a continuous tab shorter and thus the elasticity of the material of the blade certain unevenness of the profile tube can better compensate; On the other hand, each of the tabs comes into clamping contact with the profile tube, so that even with relatively large unevenness of the profile tube, each of the tabs is in clamping contact with at least one contact point with the profile tube.

Such a configuration is particularly advantageous when the profile tube on which the slats are clamped, heated by PTC elements clamped or clamped inside the tube, as in this case a subsequent widening of the with the seated slats equipped tube to achieve an improved clamping fit of the fins on the outside of the tube would lead to a loosening of the clamped inside the tube heaters and thus excretes. The inventive design of the slotted lugs of the slats makes in any case such expansion of the tube unnecessary and ensures proper heat conduction between the profile tube and the outside clamped slats.

In most cases, it is sufficient that at least two opposite edges of the openings of the slats in each case at least two slots to form each at least three adjacent tabs are provided. Of course, depending on the required heat transfer coefficient and only two or more than three juxtaposed tabs may be provided on the edges of the openings limiting the edges.

If, for example, a relatively flat profile tube with a substantially rectangular cross-section is used as the tubular heating unit, in particular the two opposite longitudinal edges of the openings of the lamellae may be interrupted by the slots arranged substantially perpendicularly to the opening, while the two further opposite transverse edges of the openings of Slats are formed continuously.

In order to stabilize the clamping seat of the lamellae on the tubular heating unit, the lamellae may each have at least one further embossing in their lateral directions of the apertures with respect to the direction of their longitudinal extension, wherein the further embossings may advantageously be in the form of beads arranged parallel to the direction of longitudinal extension of the lamellae , as it is quoted from the beginning DE 198 48 169 A1 known per se.

In order to fix the majority of on the tubular heating unit adjacent to each other and clamped on this slats against each other or clamped support is provided in a further development that the slats have at least one bent out of the lamellar plane clamping plate, which elastic to systems on a respective adjacent lamella is provided. In this way, separate components for mutual support and Fixing the lamellae dispensable, with the adjacent lamella in contact with the clamping plates can also serve to heat transfer of the fins with each other, so that local cooling of some fins largely prevented due to a non-uniform flow and the overall efficiency of the device is increased.

In a preferred embodiment, it is provided here that the clamping straps are arranged on at least two opposite ends of the slats, wherein they can be formed in particular by at least a portion of the bent out of the slat plane transverse edges of the slats.

The lamellae and optionally the tubular heating unit expediently consist of a material with good thermal conductivity, such as a metal sheet, preferably of aluminum or an aluminum alloy.

Fig. 1

eine Seitenansicht einer Ausführungsform einer erfindungsgemäßen Heizvorrichtung;

Fig. 2

einen Querschnitt durch ein Profilrohr der Heizvorrichtung gemäß Fig. 1;

Fig. 3

eine Draufsicht eines Rohlings einer Wärmeabgabelamelle vor dem Anbringen von Prägungen und vor der Ausbildung von Laschen;

Fig. 4

eine Draufsicht einer Ausführungsform einer Wärmeabgabelamelle;

Fig. 5

eine Schnittansicht der Lamelle gemäß Fig. 4 entlang der Linie V-V;

Fig. 6

eine Seitenansicht der Lamelle gemäß Fig. 4 und 5;

Fig. 7

eine Draufsicht einer anderen Ausführungsform einer Wärmeabgabelamelle, die nicht Teil der Erfindung ist;

Fig. 8

eine Schnittansicht der Lamelle gemäß Fig. 7 entlang der Linie VIII-VIII;

Fig. 9

eine Schnittansicht der Lamelle gemäß Fig. 7 und 8 entlang der Linie IX-IX gemäß Fig. 7; und

Fig. 10

eine vergrößerte Detailansicht X des Querschnittes der Lamelle gemäß Fig. 9.

The invention is explained in more detail below with reference to preferred embodiments with reference to the drawings. Showing:

Fig. 1

a side view of an embodiment of a heating device according to the invention;

Fig. 2

a cross section through a profile tube of the heater according to Fig. 1 ;

Fig. 3

a plan view of a blank of a Wärmeabgabelamelle before applying embossing and before the formation of tabs;

Fig. 4

a plan view of an embodiment of a Wärmeabgabelamelle;

Fig. 5

a sectional view of the blade according to Fig. 4 along the line VV;

Fig. 6

a side view of the blade according to 4 and 5 ;

Fig. 7

a plan view of another embodiment of a Wärmeabgabelamelle, which is not part of the invention;

Fig. 8

a sectional view of the blade according to Fig. 7 along the line VIII-VIII;

Fig. 9

a sectional view of the blade according to FIGS. 7 and 8 along the line IX-IX according to Fig. 7 ; and

Fig. 10

an enlarged detail X of the cross section of the blade according to Fig. 9 ,

In the Fig. 1 illustrated heater 1 according to the invention has, in the illustrated embodiment, two in the plane of the drawing successively arranged tubular heating units in the form of profile tubes 2, of which in Fig. 1 only the front profile tube 2 is visible.

As in particular from Fig. 2 seen, each of the profile tubes 2 is integrally formed in the form of a square tube and inside eg with a in Fig. 2 Heating device, not shown, provided in the form of resistive elements, which is a mounting frame made of insulating material, such as polyamide (Ultramid®, BASF AG), a plurality of plate-shaped PTC elements in the receptacles of the mounting frame are arranged, a over the entire mounting frame extending contact path and a contact track covering the insulating plate include (also not shown). The mounting frame can otherwise according to the mounting frame according to the DE 198 48 169 A1 be educated. Furthermore, the PTC elements used for heating, which are familiar as such, for example according to the EP 0 379 873 B1 be educated.

Again Fig. 2 can still be seen, the edges of the profile tubes designed as a square tubes 2 are each rounded. This applies not only to the outer edges 3, but also for the edges 4 arranged in the interior. In this case, the height h of the profile tubes 2 changes over their width b, wherein the lowest height is reached approximately in the middle. However, these height changes are only minor and are in the range of about 0.4 mm. Since the height of the longitudinal legs 5 of the profile tubes 2 is substantially constant, the same applies to the inner diameter of the profile tubes 2. The profile tubes 2 consequently have on the inner side 6 of their longitudinal legs 5 a spherical formation or a concave shape, whereby an excellent clamping of in the interior of the profile tubes 2 arranged and for heating the same serving PTC elements (not shown) in the profile tubes 2 is achieved.

How out Fig. 1 it can be seen sitting on the outside of the profile tubes 2 by means of clamping friction and heat-slats 7, which are used to heat to the gas to be heated, eg air, and are arranged in parallel order in the direction of extension of the tubes 2 in a row. The direction indicated by the arrow A flow of the fins 7 with the gas to be heated is provided approximately parallel to the lamellar plane and perpendicular to the extension direction of the profile tubes 2, so that the gas flow between the profile tubes 2 and the slats arranged thereon 13 passes and thereby sweeps the slat plane.

The profile tubes 2 provided with the lamellae 13 are fixed at their one end 2a to a plug-in flange 8 and at their other end 2b to a screw-on flange 9. The ends 2a, 2b of the profile tubes 2 are in recesses 10 in the plug-in flange 8 and in corresponding recesses (not shown) used in the screw 9 and fixed by caulking to the support frame thus formed. The flanges 8, 9 may for example also consist of Ultramid. The material of the profile tubes 2, for example aluminum or an alloy thereof, is optionally slightly compressed for better fixation at the ends 2 a, 2 b of the profile tubes 2. The provided between the profile tubes 2 and the support frame clamping connection can be otherwise in the in the DE 198 48 169 A1 be formed manner.

Fig. 3 shows a plan view of a blank of a Wärmeabgabelamelle 7 (see Fig. 4 to 10 ) obtained from a flat blank of an aluminum sheet obtained, for example, by a punching operation. The blank is provided with two openings 11, which are provided in the region of its longitudinal ends and extend substantially in the transverse direction of the blank or the lamella to be obtained therefrom. The openings 11 are used to pass through each one of the two profile tubes 2 of the heater 1 according to Fig. 1 , For this purpose, as described below with reference to Fig. 4 ff explained in more detail that the apertures 11 bounding edges bent to form tabs from the slat plane out, so that there is a reliable and permanent clamping connection of the slats 7 on the outside of the profile tubes 2. The longitudinal edges of the apertures 11 are perpendicular from two subdivided approximately equidistant to these slots 12 arranged so that when bending these edges three in the extension direction of the edges juxtaposed tabs ( Fig. 4 ff), which provide a perfect contact with the profile tubes 2 (FIG. Fig. 1 ) and thus ensure a good heat transfer. The formation of the two apertures 11 is identical.

The blank is further provided at its transverse edges with an approximately central projecting portion 13 which is bounded by slits 14 extending perpendicularly with respect to the transverse edges. As also below with reference to Fig. 4 ff, the projecting portions 13 of the transverse edges of the blank serve to form one clamping lug bent out of the lamellar plane, which is provided for elastic abutment against a respectively adjacent lamella 7 (cf. Fig. 1 ) and the parallel arrangement of a plurality of fins 7 on the profile tubes 2 thus stabilized.

While in 4 to 6 an embodiment of a Wärmeabgabelamelle 7a is shown, show Fig. 7 to 10 another embodiment of a Wärmeabgabelamelle 7b, each of a blank according to Fig. 3 have been obtained, which is not part of the invention. The lamellae 7a, 7b differ only by the configuration of the embossments 15 explained in more detail below on a large part of their arranged between the apertures 11 central region, which serves for heat release to the gas to be heated and in the longitudinal direction of the fins 7a, 7b in Substantially radially from the two openings 11 passing through the profile tubes 2 ( Fig. 1 ) extends away.

As in particular from Fig. 10 can be seen, the two in the longitudinal direction of the lamellae 7a, 7b opposite Edges bounding the apertures 11 are bent in an arc shape to form tabs 16 bent out of the slat plane. In the transitional region 17 of the lugs 16 to the main part of the lamellae 7a, 7b, the distance d thereof is at least the height h (FIG. Fig. 2 ) of the profile tube, while the clear distance b of the end faces of the tabs 16 is less than the height h of the profile tube 2, as long as the slats 7a, 7b have not yet been pushed over the profile tubes 2. Further, the slots 12 provide for a subdivision of the tabs 16 in the longitudinal direction of the longitudinal edges delimiting the apertures 11, so that three tabs 16a, 16b, 16c arranged next to each other (FIG. Fig. 4, 5 or 7, 8) are formed, which is the slightly concave configuration of the longitudinal leg 5 of the profile tubes 2 (FIG. Fig. 2 ) and for a perfect clamping fit of the slats 7a, 7b on the profile tube 2 and in particular ensure good thermal conduction between them.

Like also in particular the Fig. 10 can be seen, the two opposite in the transverse direction of extension of the slats 7a, 7b edges which limit the openings 11, arcuately bent to form two further bent out of the lamellar plane tabs 18, wherein the tabs 18 are formed continuously. The tabs 18 have a constant distance from each other over their extension direction, which is substantially equal to the width b (FIG. Fig. 2 ) of the profile tubes 2 corresponds. These tabs 18 serve to stabilize the clamping seat of the slats 7 a, 7 b on the profile tubes. 2

For stiffening the lamellae 7a, 7b in the region of the apertures 11, corrugations 19 extending parallel to the tabs 18 are furthermore provided, which extend laterally with respect to the longitudinal extension direction of the lamellae 7a, 7b 11 are arranged and stamped out of the lamellar plane. The embossing can be opposite or according to the deflection of the tabs 16, 18 may be provided, wherein the embossment is carried out such that the fin surface is not broken. The beads 19 stabilize the slats 7 a, 7 b in the region of the openings 11.

Due to the described design of the tabs 16, 18, the slats 7a, 7b can be frictionally pushed over the profile tubes 2 and sit on these clamped on. By the clamping seat and in particular interrupted by the slots 12 tabs 16, the slats 7 a, 7 b pressed with their profile tubes 2 facing sides of the tabs 16, 18 largely flat against the outside of the profile tubes 2 and are such on this outside of that safe heat transfer to the slats 7a, 7b is ensured.

As is apparent from the plan view of the slats 7a, 7b Fig. 4 or 7 can be seen (see also Fig. 3 ), between the adjacent tabs 16, 18 respectively rounded transition regions 20 are formed, which ensure a reliable sliding onto the profile tube 2. Further, the extending in the transverse direction of the apertures 11 tabs 18 are slightly tapered on their longitudinal sides in the direction of their free ends. The same applies to the outer tabs 16a, 16c of the extending in the longitudinal direction of the openings 11 tabs 16 at its the rounded transition areas 20 facing the end.

The projecting, central regions 13 of the opposite transverse edges of the lamellae 7a, 7b are bent out approximately arcuately from the lamellar plane to form a respective clamping lug 21, wherein the clamping lugs 21 for elastic contact with a respective adjacent lamella 7a, 7b of the heating device 1 according to Fig. 1 are provided. The clamping tabs 21 may be bent in the same or in the opposite direction as the edges of the openings 11 and form an angle α of, for example, about 50 ° with the lamellar plane ( Fig. 6 and 9 ).

Both the in 4 to 6 shown blade 7a and the blade 7b according to Fig. 7 to 10 is finally provided with embossments 15, which protrude while maintaining a continuous surface of the lamella 7 of the lamellar plane without the lamella 7 to enforce the formation of breakthroughs. The embossings 15 are arranged practically over the entire area for heat release to the gas to be heated area, which in the longitudinal direction of the slats 7 a, 7 b substantially radially from the apertures 11 passing through the profile tubes 2 (FIGS. Fig. 1 ) extends away. In the illustrated embodiments, which are equipped with two openings 11 and are accordingly provided for a heating device 1 with two profile tubes 2, this area is the region of the lamellae 7a, 7b arranged between the openings 11.

The lamella 7a has embossings 15a with a substantially rectangular base surface and a substantially trapezoidal, obliquely upwardly projecting from the lamellar plane, wherein a plurality of successively arranged in the flow direction A of the gas to be heated rows of such embossments 15a is provided, which with respect the flow direction A are arranged offset. In this case, the embossings 15a of the - in the present embodiment, four rows of embossments 15a of identical shape and applied by means of an embossing process on the lamellar plane, that the embossments 15a, although projecting from the lamellar plane or at the opposite Side of the lamella 15a are withdrawn with respect to the lamellar plane, but - as already mentioned - the lamella 7a not enforce. The individual embossments 15 are designed such that they have a steep in the flow direction A of the gas to be heated, for example, about 85 ° and a contrast flatter, over the entire height of the obliquely upwardly projecting trapezium of the embossments 15 extending waste of, for example 10 ° (see, in particular Fig. 5 ).

The embossings 15a give the lamellae 7a on the one hand an increased dimensional stability, so that it is stiffened and there is no unwanted noise even with continuous exposure to vibration. On the other hand, the embossments 15a respectively generate swirls of the gas flow passing over them (arrow A) and additionally increase the heat exchanging area of the fin 15a, so that the heat exchange between the fin 15a and the gas to be heated is considerably improved. All the more so, as can be achieved by the turbulence occurring at the embossments 15a of the gas stream A, a turbulent flow.

The embossments 15b of the lamella 7b according to Fig. 7 to 9 differ from the imprints 15a of in 4 to 6 illustrated lamella 7a according to the invention by its substantially V-shaped configuration. The tip of the "V" of the embossings 15b is aligned counter to the flow direction A of the inflowing, to be heated gas, so that at the top of the "V" is formed a stagnation point and the gas along the legs of the "V" is deflected laterally. On the one hand, a multiplicity of turbulences is generated on the one hand, and on the other hand the contact time of the gas on the slat surface is increased due to the deflections.

In the present embodiment, the legs of the "V" on a linear extension direction, wherein they can of course also be formed circular or ellipsensegmentförmig curved. Furthermore, several, e.g. three, in the flow direction A of the gas successively arranged imprints 15b provided, wherein the opening angle β of the "V" of these embossments 15b is of different sizes and increases in the direction of flow A of the gas. In this way, the gas sweeping over the lamellar plane experiences a plurality of deflections or a plurality of turbulences, so that a turbulent flow can also be achieved here and the heat exchange between the lamella 15b and the gas flow is improved particularly effectively.

Claims (13)

1. A lamella (7) for a heating device, wherein the lamella (7) is provided with embossments (15), which protrude from the lamella plane,
   wherein rows of embossments (15a) are provided, the rows being arranged one behind the other,
   wherein the rows of embossments (15a) are offset in the flow direction (A) of the gas to be heated,
   and wherein the embossments (15) of the lamella (7) have a sharp ascent and a comparatively flatter descent in the flow direction (A) of the gas to be heated, characterised in that the embossments (15a) of the lamella (7a) are quadrangular, in particular substantially trapezoidal or rectangular,
   in that the lamella (7) has at least one aperture (11) for a pipe formed as a profiled pipe (2), and
   in that at least two opposed edges of the apertures (11) are bent so as to form tabs (16) bent out from the lamella plane and are interrupted by slits (12) arranged substantially perpendicular to the aperture (11), such that a plurality of tabs (16a, 16b, 16c) arranged side by side in the direction of extension of these edges is formed.
2. The lamella according to claim 1, characterised in that the angle of the ascent of the embossments (15) with respect to the lamella surface is between approximately 45° and approximately 90°, in particular between approximately 60° and approximately 90°.
3. The lamella according to one of the preceding claims, characterised in that the angle of the descent of the embossments (15) with respect to the lamella surface is between approximately 1° and approximately 45°, in particular between approximately 1° and approximately 30°.
4. The lamella according to one of the preceding claims, characterised in that at least two slits (12) are provided on each of at least two opposite edges (16) of the apertures (11) of the lamella (7) so as to form in each case at least three tabs (16a, 16b, 16c) arranged side by side.
5. The lamella according to one of the preceding claims, characterised in that two opposite edges of the apertures (11) of the lamella (7) bent so as to form the tabs (16a, 16b, 16c) are interrupted by the slits (12) arranged substantially perpendicularly to the aperture (11), whereas two further opposite edges of the apertures (11) of the lamella (7) bent so as to form the tabs (18) are formed continuously.
6. The lamella according to one of the preceding claims, characterised in that the lamella (7) has at least one further embossment (19) in each of its lateral regions of the apertures (11), said regions being lateral with respect to the direction of longitudinal extension of said lamella.
7. The lamella according to claim 6, characterised in that the further embossments (19) are formed as beads arranged parallel to the direction of longitudinal extension of the lamella (7).
8. The lamella according to one of the preceding claims, characterised in that the lamella (7) consists of aluminium or an aluminium alloy.
9. A device (1) for heating gas flows, in particular for heating interior spaces, such as those of motor vehicles, comprising at least one substantially tubular heating unit (2) having lamellae (7) according to one of the preceding claims arranged thereon in order to dissipate heat to the gas to be heated,
   wherein the lamellae (7) are clamped on the outer face of the tubular heating unit,
   wherein the at least one tubular heating unit is formed as a profiled tube (2) and the tabs (16) sit in a clamping manner on the outer face of the profiled tube (2).
10. The device according to claim 9, characterised in that the lamellae (7) have at least one clamping tab (21), which is bent out from the lamella plane and which is provided to rest resiliently against an adjacent lamella (7).
11. The device according to claim 10, characterised in that the clamping tabs (21) are arranged on at least two opposite ends of the lamellae (7).
12. The device according to claim 11, characterised in that the clamping tabs (21) are formed by at least part (13) of the transverse edges of the lamellae (7) bent out from the lamella plane.
13. The device according to one of Claims 9-12, characterised in that the lamellae (7) and where applicable the tubular heating unit (2) consist of aluminium or an aluminium alloy.

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