Flat pipe

Abstract

The invention relates to a flat pipe, comprising two substantially flat first walls that are opposite each other and arranged parallel to each other, two arcuate second walls that connect the two flat first walls, and an interior through which a medium can flow, wherein projections that protrude into the interior are provided in at least one of the flat first walls, wherein projections that protrude into the interior are provided in the arcuate second walls.

Claims

1. A flat tube having two opposing, substantially flat first walls arranged parallel to one another, two curved second walls connecting the two flat first walls, an interior space bounded by the substantially flat first walls and the curved second walls through which a medium can flow, a first plurality of projections arranged on the substantially flat first walls protruding into the interior space, a second plurality of projections arranged on the curved walls protruding into the interior space, and a third plurality of projections arranged on the substantially flat first walls protruding outwardly and away from the interior space, wherein the projections of the first plurality of projections are each elongated having a greater length than width and are each arranged in a repeating pattern alternating between an x-shape and an o-shape such that each projection of the first plurality of projections forms part of an x-shape or part of an o-shape, wherein the x-shape and the o-shape each consist of four distinct projections, wherein each x-shape in the repeating pattern is adjacent to an o-shape and each o-shape in the repeating pattern is adjacent to an x-shape, wherein the flat tube does not have any projections other than the first plurality of projections, the second plurality of projections, and the third plurality of projections.

2. The flat tubes as claimed in claim 1, wherein the projections from the first plurality of projections are arranged with a first repeat rate along the longitudinal axis of the flat tube.

3. The flat tubes as claimed in claim 2, wherein the projections from the second plurality of projections are arranged with a second repeat rate along the longitudinal axis of the flat tube.

4. The flat tube as claimed in claim 3, wherein the first repeat rate substantially corresponds to a whole-number multiple of the second repeat rate greater than one.

5. The flat tube as claimed in claim 3, wherein the second repeat rate is twice the first repeat rate.

6. The flat tube as claimed in claim 1, wherein the outwardly protruding projections from the third plurality of projections are in every instance arranged inside the o-shape.

7. The flat tube as claimed in claim 1, wherein the projections from the first plurality of projections are arranged so as to complement one another, so that an x-shaped arrangement in a first wall of the substantially flat first walls is situated opposite an o-shaped arrangement of an opposing second wall of the substantially flat first walls.

8. The flat tube as claimed in claim 1, wherein the projections from the second plurality of projections have an oval cross section with respect to a surface of the curved second walls.

9. The flat tube as claimed in claim 1, wherein a center of a projection from the second plurality of is substantially aligned with a center of a projection from the first plurality of projections.

10. The flat tube as claimed in claim 1, wherein at least one end area of the flat tube is formed without projections.

11. The flat tube as claimed in claim 10, wherein recessed end areas for the respective projections deviate from one another.

12. The flat tube as claimed in claim 1, wherein there are no projections arranged between the x-shape and the o-shape in the repeating pattern.

13. A heat exchanger, wherein the heat exchanger comprises a plurality of flat tubes, wherein the each of the flat tubes of the plurality of flat tubes is a flat tube having (i) two opposing, substantially flat first walls arranged parallel to one another, two curved second walls connecting the two flat first walls, and (ii) an interior space bounded by the substantially flat first walls and the curved second walls through which a medium can flow, a first plurality of projections arranged on the substantially flat first walls protruding into the interior space, a second plurality of projections arranged on the curved walls protruding into the interior space, and a third plurality of projections arranged on the substantially flat first walls protruding outwardly and away from the interior space; wherein the projections from the first plurality of projections are elongated having a greater length than width and are each arranged in a repeating pattern alternating between an x-shape and an o-shape such that each projection of the first plurality of projections forms part of an x-shape or part of an o-shape, wherein the x-shape and the o-shape each consist of four distinct projections, wherein each x-shape in the repeating pattern is adjacent to an o-shape and each o-shape in the repeating pattern is adjacent to an x-shape.

14. A flat tube having two opposing, substantially flat first walls arranged parallel to one another, two curved second walls connecting the two flat first walls, an interior space bounded by the substantially flat first walls and the curved second walls through which a medium can flow, a first plurality of projections arranged on the substantially flat first walls projecting into the interior space, a second plurality of projections arranged on the curved walls protruding into the interior space, and a third plurality of projections arranged on the substantially flat first walls protruding outwardly and away from the interior space, wherein both of the opposing, flat first walls each have projections from the first plurality of projections protruding into the interior space, wherein both of the opposing, curved second walls have projections from the second plurality of projections protruding into the interior space, wherein both of the two opposing, substantially flat first walls have outward-facing projections from the third plurality of projections, wherein the projections from the first plurality of projections are elongated having a greater length than width and are each arranged in a repeating pattern alternating between an x-shape and an o-shape such that each projection of the first plurality of projections forms part of an x-shape or part of an o-shape, wherein each x-shape in the repeating pattern is adjacent to an o-shape and each o-shape in the repeating pattern is adjacent to an x-shape, wherein there are no projections arranged between the x-shape and the o-shape in the repeating pattern, wherein the x-shape and o-shape each consist of four distinct projections, wherein the outwardly protruding projections from the third plurality of projections are arranged inside the o-shape in every instance, wherein the projections from the first plurality of projections are arranged so as to complement one another, so that an x-shaped arrangement in a first wall of the substantially flat first walls is situated opposite an o-shaped arrangement of an opposing second first wall of the substantially flat first walls, wherein the projections from the second plurality of projections have an oval cross section with respect to a surface of the curved second walls, wherein a center of a projection from the second plurality of projections is substantially aligned with a center of a projection from the first plurality of projections, wherein the flat tube does not have any projections other than the first plurality of projections, the second plurality of projections, and the third plurality of projections.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in detail below on the basis of an exemplary embodiment, referring to a drawing, in which:

(2) FIG. 1a shows a schematic view of a flat tube viewed from above,

(3) FIG. 1b shows a schematic view of a flat tube viewed from the side,

(4) FIG. 1c shows a schematic view of a flat tube viewed from below,

(5) FIG. 1d shows a schematic view of a flat tube viewed from the front,

(6) FIG. 1e shows a schematic, perspective view of a flat tube,

(7) FIG. 2a shows a schematic view of a flat tube viewed from above,

(8) FIG. 2b shows a schematic view of a flat tube viewed from the front,

(9) FIG. 2c shows a schematic, perspective view of a flat tube,

(10) FIG. 3a shows a schematic view of a detail of a flat tube viewed from above,

(11) FIG. 3b shows a schematic view of a detail of a flat tube viewed from below,

(12) FIG. 3c shows a schematic view of a projection in a curved wall.

PREFERRED EMBODIMENT OF THE INVENTION

(13) FIGS. 1a to 1e show an exemplary embodiment of a rounded flat tube 1, which has two opposing, flat first walls 2, 3. The two flat first walls 2, 3 are of substantially flat design and are arranged parallel to one another. The flat first walls 2, 3 are connected to one another by means of curved second walls 4, 5 on the longitudinal side of the flat first walls 2, 3. Here the curved second walls 4, 5 are of semicircular or otherwise curved design.

(14) Between the substantially flat first walls 2, 3 and the curved second walls 4, 5 the flat tube defines an interior space 6 allowing a medium to flow through the flat tube. The medium is preferably exhaust gas or an exhaust gas-air mixture. Toe flat tube is advantageously used as a tube of a exhaust gas recirculation cooler or a charge-air intercooler.

(15) As can be seen, projections 7, which protrude into the interior space 6 of the flat tube 1, where they are intended to achieve a swirling of the medium flowing through the flat tube 1, are impressed in the flat first walls 2, 3.

(16) Here the projections 7 are impressed into the flat first wall 2, 3 as elongated projections 7. As can be seen from FIGS. 1a to 1e, the projections 7 are arranged impressed into the opposing walls 2, 3 in an x-shape and an o-shape, the x-shaped impressions 8 alternating with the o-shaped impressions 9 viewed in the longitudinal direction of the flat tube 1.

(17) An o-shaped arrangement of the projections here means that four of the projections are arranged in a diamond pattern, so that they form an O, as it were. An x-shaped arrangement of the projections here means that four of the projections are arranged in an x or star shape, so that they form an X, as it were.

(18) Outward-facing projections 10, which may serve as spacers for adjacent flat tubes 1, are furthermore provided in the walls 2, 3, the outwardly protruding projections 10 being arranged in the area of the projections arranged in an o-shape. The projections are arranged in the center of four projections 7 arranged in an o-shape.

(19) Compared to FIGS. 1a and 1c it can be seen that the arrangement of the projections 7 on one wall 2 is staggered in comparison to the arrangement of the projections 7 on the opposing wall 3. Thus in the case of an x-shaped arrangement 8 of the projections 7 on the wall 2 there is an o-shaped arrangement 9 of the projections 7 on the wall 3 opposite, and vice versa. The arrangement of the outwardly protruding projections 10 is also staggered between opposing first walls 2, 3.

(20) It can also be seen that projections 11, which protrude from the curved second wall 4, 5 into the interior space 6 of the flat tube 1, are provided in the curved second wall 4, 5.

(21) The periodic repetition of the projections of repeat length L is drawn in in the exemplary embodiment in FIGS. 1a to 1e, the periodic repetition of the projections being denoted by the repeat length I. Here the repeat length is the length after which the same pattern reoccurs. The repeat length i in FIGS. 1a to 1e is half the repeat length L, so that the repeat rate of the projections 11 is twice the repeat rate of the projections 7.

(22) It can be seen from FIGS. 1a to 1e that the projections 11 are arranged opposite in the two curved second walls 4, 5. Alternatively the projections 11 in one curved wall 4 may also be staggered in relation to the projections 11 in the opposing wall 5.

(23) FIGS. 2a to 2c show a further exemplary embodiment of a flat tube 21 according to the invention, which like the exemplary embodiment in FIGS. 1a to 1e has substantially flat first walls 22, 23, which are situated opposite one another and are arranged parallel to one another. The first wall 22, 23 are connected to one another by second curved walls 24, 25. Here projections, such as impressions 27, 28, which protrude from the first walls 22, 23, are provided in the flat first walls. Here the projections 27 protrude into the interior space 26 and the projections 28 protrude outwards.

(24) Projections 29, which protrude into the interior space 26, are likewise provided in the curved second walls 24, 25. The arrangement of the projections 27, 28 corresponding substantially to the arrangement of the projections 7, 10 in FIGS. 1a to 1e, the arrangement of the projections 29 corresponding substantially to the arrangement of the projections 11 in FIGS. 1a to 1e. The difference between the exemplary embodiment in FIGS. 2a to 2c and the exemplary embodiment in FIGS. 1a to 1e is that the repeat length L in the exemplary embodiment in FIGS. 2a to 2c corresponds to the repeat length L of the projections 27.

(25) FIGS. 3a and 3b show the arrangement of a projection 29 in relation to the arrangement of the projections 27. It can be seen here that the center 30 of the projection 29 is approximately on the same level as the center 31 of a projection 27. The projection 29 is therefore centered on a projection 27, which is arranged in an o-shape with a group of projections 27, a projection 28 being arranged at the center of the o-shaped arrangement.

(26) FIG. 3c shows the extent of a projection 29 by way of example, the extent transversely to the longitudinal direction of the flat tube, the stamping depth, being approximately 1.0 mm and the stamping radii and the run-out radii each being approximately 6.0 mm. The stamping depth of the projections 29 may suitably be selected in the range between 0.5 mm and 1.2 mm, in order for them to protrude sufficiently far into the interior space in relation to the curved second wall. Here the impression is formed by a central stamping radius having two edge run-out radii. The length, transversely to the stamping depth, may here advantageously be the multiple of the stamping depth.

(27) It can seen from FIGS. 3b and 3a that the projections 27 are arranged at an angle of approximately 22 to the longitudinal axis of the tube, the projections 28 being of circular or oval design, the longitudinal axis in the case of an oval stamping being arranged parallel to the longitudinal axis of the tube.