HEAT EXCHANGER WITH INTERMEDIATE PLATE

Abstract

The present invention relates to a heat exchanger, in particular, an oil cooler for motor vehicles, constructed from trough-shaped heat exchanger plates which are stacked into one another and from turbulence inserts, having two openings for one medium and two further openings for another medium in order to form collecting ducts for the supply and discharge of the media, with flow ducts for the media being formed between the heat exchanger plates. The heat exchanger also includes flow ducts connected to the associated collecting ducts, an upper closure plate which has convexities in the region of the collecting tanks, and an intermediate plate which is provided with holes. The intermediate plate is arranged between the closure plate and the uppermost heat exchanger plate, and one of the holes, formed as a pressure equalizing opening, interacts with the upwardly aligned convexity in the closure plate to improve the internal pressure stability.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority is hereby claimed to German Patent Application No. DE 10 2007 011 762.2, filed Mar. 10, 2007, the entire contents of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a heat exchanger, such as an oil cooler, having a connecting plate.

SUMMARY

DE 103 49 141 A1 discloses a plate heat exchanger constructed from trough-shaped heat exchanger plates which are stacked into one another. This type of heat exchanger is used in a vehicle as an oil cooler. The publication proposes a solution which can withstand internal pressures of 6 to 10 bar. This is obtained by using an intermediate plate as a tie rod which is inserted and soldered in between the closure plate and the final, uppermost turbulence insert. The intermediate plate has the same hole pattern as the turbulence insert which is soldered to it. The structural principle proposed there has the disadvantage that, at yet higher internal pressures, defects can occur, since the turbulence plates are usually produced from metal sheets of very low wall thickness which are restricted in terms of their resistance to extreme internal pressures. The known closure plate has convexities in the region of the collecting ducts, which convexities are aligned substantially inward.

It is the object of the invention to further improve the resistance of the heat exchanger to internal pressure. The object is achieved according to the invention with the generic heat exchanger by means of its refinement as explained in greater detail below.

Because the intermediate plate is arranged between the closure plate and the uppermost heat exchanger plate, and because at least one of the holes therein interacts, as a pressure equalizing opening, with the upwardly aligned convexity in the closure plate, the heat exchanger is now also suitable for internal pressures of considerably higher than 10 bar. The pressure equalizing opening makes it possible, for example, for the oil to enter into the space between the convexity and the intermediate plate and to impart a force there which counteracts the force which acts between the heat exchanger plate and the intermediate plate. A certain pressure release is thereby obtained.

A pressure release is also obtained in that the closure plate is replaced by a closure disk which has the convexity and which is connected to the intermediate plate, with the diameter of the convexity being greater than the diameter of the collecting duct, with the intermediate plate being arranged on the uppermost heat exchanger plate. The alternative proposed solution therefore dispenses entirely with the closure plate and uses merely a closure disc which is slightly larger than the duct which it closes off. The size of the diameter of the pressure equalizing opening D is in the range from 1 mm to 10 mm, preferably in the range from 1 mm to 2 mm.

The closure plate and the intermediate plate can have different thicknesses a and z. The values are in the range of 1 mm to 3 mm for the thickness a and in the range from 1 mm to 2 mm for the thickness z.

The convexities in the closure plate have a greater diameter than the collecting ducts of the media.

An alternative or additional possibility for increasing the internal pressure stability is to design the penultimate turbulence plate, which is situated in the flow duct of the one medium, in such a way that it does not have an opening like the other turbulence plates. A preferably small hole which has the function as a pressure equalizing opening can however be provided in the turbulence plate in the region of the collecting tank.

The lowermost heat exchanger plate is formed from a thicker metal sheet than the other heat exchanger plates. The fastening plate is also of at least two-part design.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The invention is now briefly described in various exemplary embodiments with reference to the appended drawings.

FIG. 1 shows a section through an embodiment of the heat exchanger of the present invention.

FIG. 2 shows an enlarged detail from FIG. 1.

FIG. 3 shows a section through an alternative embodiment of the heat exchanger of the present invention.

FIG. 4 shows an enlarged detail from FIG. 3.

FIG. 5 shows a plane view of the intermediate plate.

FIG. 6 shows a sectional view of an alternative embodiment of the heat exchanger of the present invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

The basic design of the heat exchanger is described with respect to FIGS. 1-3. The heat exchanger is a plate heat exchanger, in particular an oil cooler 1. The latter is constructed from trough-shaped heat exchanger plates 10 which are stacked into one another and which bear against one another with their edges 100. Constantly alternating flow ducts 8 and 9 for the two media (e.g., oil 8 and coolant 9), are formed between in each pair of heat exchanger plates 10. The heat exchanger plates 10 are identical and are stacked on top of one another, rotated through 180°, in order to form the heat exchanger.

Circular openings 21, 31 are provided in the heat exchanger plates 10. The openings 21, 31 are provided with projecting edges 101, 102. The projecting edges 101, 102 bear against one another and thereby define the collecting ducts 20 and 30 for the two media, which collecting ducts 20 and 30 are hydraulically connected to the associated flow ducts 8 and 9. Turbulence inserts 5 are arranged in the flow ducts 8, 9 between two heat exchanger plates 10. Other turbulence-generating means, such as for example knobs, beads or the like, could also be inserted into the flow ducts 8 and 9, which are not shown here. The lowermost heat exchanger plate 13 is produced from a thicker metal sheet of approximately 2 to 5 mm thickness. In this manner, the heat exchanger 1 is more stable at high internal pressures and occurring vibrations.

The two exemplary embodiments show a fastening plate 14(a+b) which is of two-part design but can also be of single-part or three-part design. Inlet and outlet openings 25, 35 for the two media are situated in said fastening plate 14, which media are in this case conducted into and out of the heat exchanger 1 through the fastening plate 14. The connecting pipes for the two media can alternatively or also be formed on the upper closure plate 12 (not shown). The edge of the closure plate 12 is ideally soldered to the edge 100 of the uppermost heat exchanger plate 10. For this purpose, the edge 100 can be formed by bending or by means of chamfering/beveling, so that the edge 100 is approximately form-fitting with respect to the edge 100 of the uppermost heat exchanger 10.

FIGS. 1 and 2 show the first embodiment. An additional intermediate plate 11 is placed between the uppermost heat exchanger plate 10 and the closure plate 12. During soldering, the intermediate plate 11 is then connected to the adjacent plates. The closure plate 12 sealingly closes off the four collecting ducts 20 and 30 of both media. Above the collecting ducts 30 which collect one medium (e.g., oil) at least one convexity 6 is formed upward or outward in the closure plate 12. In the intermediate plate 11 situated below the latter, in each case one hole 3 is situated above the collecting ducts 20 of the other medium, which hole 3 is large enough to hold the projecting edge 101 of the opening 21 of the uppermost heat exchanger plate 10.

Situated in the intermediate plate 11 above the collecting ducts 30 of one medium is another hole 2 whose diameter D is less than or equal to the diameter d of the collecting ducts 30. The diameter D is ideally in the range from 1 to 10 mm, though a very small hole 2 which does not close up during soldering is sufficient. The stresses which act are conducted outward via the intermediate plate 11 into the region outside the collecting ducts 30. The uppermost turbulence insert 5 in particular is protected. This is because, at high internal pressures in the range of 10 to 15 bar or more, the uppermost turbulence insert 5 would, without the intermediate plate 11, be torn open by the occurring stresses. In addition, the shape of the convexities 6 in the closure plate 12 ensures that the occurring forces are conducted outwardly more effectively. The diameter AP of the convexity 6 is therefore greater than the diameter d of the collecting ducts 30.

FIG. 5 shows a plan view of the intermediate plate 11. The figure is a simplified sketch. It is possible to see an edge region with the holes 2 and 3. It can be clearly seen that the diameter D of the hole 2 in the intermediate plate 11 is ideally significantly smaller than the diameter d of the collecting duct 30. In particular, the shape of the hole 2 in the intermediate plate 11 can be freely selected, but is preferably circular or oval.

FIGS. 3 and 4 show an additional or alternative possibility of how the heat exchanger 1 can be yet more stable with respect to high internal pressures of one medium (e.g., oil). Here, the penultimate turbulence insert 5 in the upward direction is changed in the region of the collecting ducts 30, specifically in such a way that the turbulence insert 5 is not provided with an opening 31 in the region of the collecting ducts 30 but rather is of continuous design. Such turbulence inserts 5 are, as is known, corrugated sheets, in that the corrugations of which are provided incisions or the like which make it possible for the medium to flow through them (not shown). The measure contributes to the forces being distributed between the various heat exchanger plates 10 and turbulence inserts 5 yet more effectively. The turbulence insert 5 can however be provided with a pressure equalizing opening in the region of the collecting duct 30.

FIG. 6 shows a heat exchanger which does not have a closure plate 12 but rather has, in its place, merely a circular closure disk 60 which lies on and is soldered to the intermediate plate 11. The closure disk 60 is slightly larger in diameter than the collecting duct 30. The closure disk 60 has a convexity 6, whose diameter is slightly larger than the collecting duct 30, and in the centre of the convexity 6, an inwardly aligned convexity 61. Here, too, the intermediate plate 11 lies on the uppermost heat exchanger plate 10. Since the intermediate plate 11 is thinner than a closure plate, the weight of the heat exchanger is reduced. The thickness of the closure plate 60 can correspond to the thickness of the intermediate plate 11 since the convexity 6 ensures stiffness.

Various features and advantages of the invention are set forth in the following claims.

Claims

1. A heat exchanger, in particular an oil cooler for motor vehicles, the heat exchanger comprising:

a plurality of trough-shaped heat exchanger plates which are stacked into one another, each of the plurality of heat exchanger plates having two openings for one medium and two further openings for an other medium in order to form collecting ducts for the supply and discharge of the one media and the other media;

flow ducts for the media being formed between the heat exchanger plates, the flow ducts being connected to the associated collecting ducts;

turbulence inserts arranged in the flow ducts;

an upper closure plate which has convexities adjacent at least one of the collecting ducts; and

an intermediate plate which is provided with holes;

wherein the intermediate plate is arranged between the closure plate and an uppermost heat exchanger plate, and wherein one of the holes interacts, as a pressure equalizing opening, with the upwardly aligned convexity in the closure plate.

2. The heat exchanger according to claim 1, wherein the upwardly aligned convexities of the closure plate have a spherical-cap-like profile.

3. The heat exchanger according to claim 2, wherein the upwardly aligned convexities of the closure plate have a larger diameter than the collecting ducts.

4. The heat exchanger according to claim 1, wherein a diameter of the holes in the intermediate plate is significantly smaller than a diameter of the collecting tank.

5. The heat exchanger according to claim 4, wherein the diameter of the holes is between about 1 mm and about 2 mm.

6. The heat exchanger according to claim 1, wherein the closure plate and the intermediate plate have different thicknesses.

7. The heat exchanger according to claim 6, wherein the thickness of the closure plate is between about 1 mm and about 3 mm and the thickness of the intermediate plate is between about 1 mm and about 2 mm.

8. The heat exchanger according to claim 1, wherein at least one of the turbulence inserts, in a region of the collecting tank in which the pressure equalizing opening is situated, is formed without an opening.

9. The heat exchanger according to claim 8, wherein the turbulence insert includes at least one pressure equalizing opening.

10. The heat exchanger according to claim 1, wherein a lowermost heat exchanger plate is formed from a thicker metal sheet than the other heat exchanger plates.

11. The heat exchanger according to claim 1, further comprising a fastening plate of at least two-part design.

12. The heat exchanger, in particular oil cooler for motor vehicles, the heat exchanger comprising:

a plurality of trough-shaped heat exchanger plates stacked into one another and having two openings for one medium and two further openings for an other medium in order to form collecting ducts for the supply and discharge of the one media and the other media;

turbulence inserts;

flow ducts for the media formed between the heat exchanger plates and connected to the associated collecting ducts;

an intermediate plate which is provided with holes; and

a closure disk in the region of the collecting ducts and having a convexity which is connected to the intermediate plate;

wherein a diameter of the convexity is greater than a diameter of the collecting duct, and wherein the intermediate plate is arranged on an uppermost heat exchanger plate.

13. The heat exchanger according to claim 12, wherein an inwardly aligned convexity is provided in a center of the convexity.