DIMPLE CHILLER WITH SECONDARY DIMPLES

Abstract

A heat exchanger with at least one plate includes main dimples between which secondary dimples are formed which are flatter and/or smaller with respect to their dimensions as seen in a plan view. A depth of the secondary dimples may be at most 0.5 times a channel height and/or at most 0.5 times the depth of the main dimples.

Claims

1.-10. (canceled)

11. A heat exchanger with at least one plate having main dimples, between which secondary dimples are formed which are flatter and/or smaller with respect to their dimensions as seen in a plan view.

12. The heat exchanger according to claim 11, wherein a depth of the secondary dimples is at most 0.5 times a channel height and/or at most 0.5 times a depth of the main dimples.

13. The heat exchanger according to claim 11, wherein a distance between the main dimples and the secondary dimples in at least one direction is 1.9 to 2.5 mm.

14. The heat exchanger according to claim 11, wherein one of the secondary dimples is formed in each case between two of the main dimples.

15. The heat exchanger according to claim 11, wherein the main dimples are arranged in rows, and the secondary dimples are arranged on the rows of main dimples.

16. The heat exchanger according to claim 15, wherein the rows of the main dimples are formed obliquely to at least one edge of the at least one plate.

17. The heat exchanger according to claim 11, wherein a sheet thickness of the at least one plate in an area of the main dimples and/or the secondary dimples is less than between the dimples.

18. The heat exchanger according to claim 11, wherein the main dimples and/or the secondary dimples have a circular, an elliptical, or an oval shape in plan view.

19. The heat exchanger according to claim 18, wherein a main axis of the main dimples having the elliptical or the oval shape are parallel to an edge of the at least one plate, in particular a longer edge of a rectangular plate.

20. The heat exchanger according to claim 18, wherein a main axis of the secondary dimples having the elliptical or the oval shape extend at an angle with respect to edges of a rectangular plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further details of the invention can be seen from the drawings.

[0018] FIG. 1 shows a plan view of a plate of a conventional heat exchanger with dimples.

[0019] FIG. 2 shows a plate similar to that of FIG. 1, which additionally comprises the secondary dimples according to the invention.

[0020] FIG. 3 is a graph showing the increase in performance of a heat exchanger with the plates of FIG. 2 compared to the heat exchanger with the plates of FIG. 1.

[0021] FIGS. 4 and 5 show plates similar to those of FIGS. 1, 2, 4 and 5 including their dimensions.

[0022] FIG. 6 shows the plate of FIG. 8 including one detail and preferred sizes of the dimples.

[0023] FIG. 7 shows further experimental results indicating an increase in performance of the new type of plate by between 6.2 and 10.2%, without changing neither the size of the plate nor the amount of material used, although the secondary dimples are formed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0024] As can be seen in FIG. 1, a plate 100 of a heat exchanger comprises numerous dimples which in this case, in plan view, are oval dimples 102 that are arranged on lines extending obliquely to the plate edges, which do not quite correspond to the diagonals of the rectangle forming the plate shape. In particular, two groups of rows can be seen, one extending from bottom left to top right and the other from bottom right to top left, and which in the case shown intersect at an angle smaller than 90 degrees.

[0025] In the plate 10 of a heat exchanger according to the invention according to FIG. 2, the arrangement of the main dimples 12 substantially corresponds to that of the (only present) dimples 102 as shown in FIG. 1.

[0026] According to the invention, one secondary dimple 14 is formed in each case between every two main dimples 12, which in this case in plan view is both smaller and, not visible in plan view, flatter. In particular, precisely one secondary dimple 14 is formed in each case between two main dimples 12, and therefore four secondary dimples are formed in the vicinity of every main dimple. As is also preferred, the secondary dimples are located on those lines or rows that are described by the main dimples. In the case shown, the main dimples 12 are oval when viewed from the top, with their longer axis extending parallel to the longer edge of the rectangular plate 10, and the secondary dimples are circular when viewed from the top.

[0027] As is revealed in FIG. 3, which shows a performance comparison of the plates from FIGS. 1 and 2 in a two-sided heated wall, there appears an increase in performance from 2.0 to nearly 5% depending on the coolant flow.

[0028] FIG. 4 shows a further plate 100 comprising only a single type of dimple 102.

[0029] In contrast, a plate 10 according to the invention according to FIG. 5 is provided with both main dimples 12 and secondary dimples 14. Unlike the plates of FIGS. 1, 2, and 4, the main dimples 12 and the secondary dimples 14 are also arranged in intersecting rows in this embodiment, which also in this case do not correspond to the diagonals of the rectangular plate. However, they are arranged at an angle of 90 degrees to each other in this embodiment. Moreover, in this case, both the main dimples 12 and the secondary dimples 14 are circular in plan view. The plates of FIGS. 4 and 5 can typically be between 60 mm and 100 mm wide and between 80 mm and 140 mm long. According to an exemplary embodiment, they are each 64 mm wide and 102 mm long.

[0030] The shape and alignment of the main dimples 12 and the secondary dimples 14 can be seen more clearly in the detailed view of FIG. 6. In particular, four secondary dimples 14 are arranged here around one main dimple 12 at a constant spacing of 90 degrees. The main dimples of the plate of FIG. 6 can have a diameter of 4.1 mm and a depth of 1.2 mm. 67 dimples of this type can be present on the plate shown in FIG. 6. The secondary dimples can have a diameter of 1.9 mm and a depth of 0.6 mm, and 140 dimples of this type can be formed on the plate shown in FIG. 9.

[0031] As is apparent from FIG. 7, there is an increase in performance, depending on the coolant flow, between 6.2 and 10.2%.