Stacked plate heat exchanger

A stacked plate heat exchanger may include a plurality of elongated plates on top of and connected to one another. The elongated plates may define a first cavity in the longitudinal direction of the plates and be configured to cool a medium. The elongated plates may define a second cavity for conducting a coolant therethrough, wherein in two end regions of each elongated plate, a through hole may be arranged for supplying the medium to be cooled. The through hole may be at least partially surrounded at its boundary by a dome and arranged approximately at the edge of the elongated plates. At least one of the dome and the through hole may be integrated in the edge of the elongated plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application 10 2010 028 660.5, filed on May 6, 2010, and International Patent Application PCT/EP2011/057091, filed on May 4, 2011, both of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The invention relates to a stacked plate heat exchanger having a plurality of elongated plates which are stacked on top of each other and connected to one another, and which have a cavity through which a medium to be cooled is conducted in the longitudinal direction of the plates, and which plates delimit a further cavity for conducting a coolant therethrough, wherein approximately in the two end regions of each elongated plate, a through hole is arranged for supplying the medium to be cooled, which through hole is at least partially surrounded at its boundary by a dome.

BACKGROUND

Stacked plate heat exchangers which cool air fed to an internal combustion engine by means of oil-coolant or air cooling are well known in the cooler industry.FIG. 1shows an elongated plate of a stacked plate heat exchanger which is cooled with oil. In the perspective view ofFIG. 1a, the elongated plate1has a plate rim2and a plurality of circular-segment-shaped, stamped through holes3. At least 2 of the circular-segment-shaped stamped through holes3are surrounded by a dome4(FIG. 1b). As can be seen from the cross-section inFIG. 1c, each through hole3has a distance5from the edge of the plate. This results in that the effectiveness of the heat exchanger is limited because not all regions of the elongated plate are utilized for heat transfer.

A similar arrangement is given in the case of a stacked plate heat exchanger which is cooled with air and which is illustrated inFIG. 2. Here too, the stacked plate heat exchanger consists in particular of a plurality of elongated plates6of which only one is shown inFIG. 2. This elongated plate6is completely surrounded by a plate rim7. Each plate6has two through holes8for the medium to be cooled and, furthermore, two through holes9for the coolant. As is shown inFIG. 2b, the through hole8as well as the through hole9is surrounded by a dome10,11. Such a dome10,11in the plates6is necessary so as to separate the coolant from the medium to be cooled in the heat exchanger. The described arrangement of the through holes8and9in the plate6results in increased material requirements and a more complex plate geometry due to a higher degree of forming with regard to the through holes8and9. Also, a disadvantage here is that for the available volume to be installed only limited power for heat exchange is available.

SUMMARY

It is therefore an object of the present invention to provide a stacked plate heat exchanger with which, while maintaining a simple plate geometry, a maximum power-to-volume ratio during the heat transfer is achieved.

According to the invention, the object is achieved in that the through hole is arranged approximately at the edge of the elongated plate, wherein the dome and/or the through hole is integrated in the edge of the elongated plate. This has the advantage that no thermotechnically ineffective regions are present in the heat exchanger when using the elongated plate. Thus, the entire elongated plate is utilized for the heat exchange, which results in a compact design. Said compact design enables saving material cost and allows a simpler plate geometry.

Advantageously, the dome is arranged adjacent to a rim delimiting a base plate of the elongated plate. Thus, the available installation space is fully utilized because the heat exchange takes place over the entire surface of the elongated plate.

In one configuration, the dome is arranged in a different plane than the rim of the elongated plate, wherein said dome is preferably embossed into the base plate or is raised and protrudes from the base plate. This arrangement results in an improved stackability of the individual plates of the heat exchanger.

Advantageously, in another embodiment, the dome can completely fill a space between a rim delimiting a base plate of the plate and the respective through hole. Through this, the available installation space is optimally utilized without creating dead spaces for the medium to be cooled.

In a refinement, the through hole is arranged in a different plane than the elongated plate. This configuration too improves stackability of the elongated plates.

In one variant, the dome has a plurality of elongated holes feeding the coolant. This increases the compactness of the component because the dome is used as a spacer to the elongated plate arranged thereabove and also receives on the same surface the elongated holes for conducting the coolant therethrough.

Furthermore, the through hole is approximately circular-segment-shaped, wherein the elongated holes surrounding the through hole are curved in a circular-arc-shaped manner. Through this configuration, consumption of material is reduced and an optimal plate geometry is achieved.

In one refinement, the dome of a first elongated plate together with a further elongated plate arranged therebelow or thereabove forms an annular channel which is interrupted by the elongated holes. By using the dome for the annular channel in which the coolant is transported, material requirements for the heat exchanger can be further reduced and the design can be configured in a particularly compact manner.

In another advantageous embodiment, the base plate can lie in a first plane which lies between a second plane, in which the respective through hole lies, and a third plane in which the elongated holes lie. Thus, within a small area, a multi-step structure is obtained which is characterized by a high stiffness.

According to another advantageous embodiment, the dome can at least partially be integrated in a rim delimiting a base plate of the elongated plate. In this case, rim and dome quasi transition into each other and enable dual use of the respective wall section. This results in a particularly compact structure.

Particularly advantageous is a refinement in which an outer dome wall running along the edge of the plate is integrated in the rim. In other words, said outer wall of the dome forms an integral part of the rim when dome and rim are arranged on the same side of the plate, or forms an integral extension of the rim when dome and rim are arranged on opposite sides of the plate. This too results in a particularly compact design.

Advantageously, the dome is formed with a predetermined inclination angle which is in particular directed inward toward the through hole. Through this, stackability of the elongated plates is further improved because gaps which can occur in the solder joint of the plates lying on top of one another are prevented.

Furthermore, between a closure region of the dome and the rim, a segment is formed, the further inclination angle of which is larger than the predetermined inclination angle of the dome, wherein the deviation of the predetermined inclination angle of the dome from the further angle of the segment is approximately 5°. Through this geometry, the rim of the elongated plate has clearance in the region of the dome resulting in a circumferential soldering joint lying in one plane. Leakages within the heat exchanger are reliably prevented.

In particular, the segment is arranged at the height of the dome and ends flush with the elongated plate. This embodiment requires only a minor change in the degree of forming during the fabrication of the dome.

In another embodiment, a cam is formed on the dome at least in one closure region of the dome, which cam has approximately the predetermined inclination angle of the rim and preferably extends parallel to the dome. This cam seals a channel which is formed by using the different angles of the dome and the segment when stacking two elongated plates on top of one another.

Advantageously, the closure region of circular-arc-shaped dome is configured in a semicircular manner. Through the configuration of the closure region of the dome, said cam forms a kind of a closure in order to limit any liquid that penetrates through this channel into the heat exchanger. The cam can be kept very small in terms of its dimensions. In a refinement, said cam has an extension of less than 6 mm.

In one refinement, the dome and at least one cam are integrally formed from the elongated plate. These parts can easily be manufactured as stampings. Manufacturing is carried out in a single work step which requires only simple tools. This reduces manufacturing costs significantly.

Advantageously, the elongated plate is formed from solderable aluminum. By using this easily-formable material, manufacturing the stacked plate heat exchanger is simplified and material costs are reduced.

The invention allows different embodiments. Some of them shall be explained in more detail by means of the figures illustrated in the drawing.

DETAILED DESCRIPTION

Identical features are designated with identical reference numbers.

FIG. 3shows an elongated plate6of a stacked plate heat exchanger for air cooling, wherein the said plate is oval. This elongated plate6consists of a base plate12around the edge of which a boundary7is attached. This boundary7is at an angle of approximately 90° to the base plate12and serves for a better stacking of the different plates6on top of one another. On the opposite ends of the plate6, in each case one through hole8is arranged which is machined out of the plate6. Each through hole8is positioned so close to the edge of the boundary7that between the through hole8and the boundary7only a dome10is arranged, which is also designated as passage. Thus, this passage10completely fills the space between the boundary7and the through hole8. The through hole8has a semicircular shape, wherein the radius of the semicircle is completely surrounded by the passage10.

FIG. 3bshows a closer view of a through hole8awith the passage10surrounding said hole. The passage10has a plurality of elongated holes13which fill the entire surface of the passage10and which face away from the base plate12of the elongated plate6. Said passage is raised above the plane predetermined by the base plate12so that the elongated holes13are positioned in a plane above the plane spanned by the base plate12.

The medium to be cooled is fed through the through hole8ato the heat exchanger and is discharged again from the heat exchanger through the additional through hole8bwhich is illustrated inFIG. 3a. The elongated holes13serve for feeding the cooling medium, in this case air, to the heat exchanger. Between the two through holes8a,8b, turbulence inserts are arranged which are not illustrated here and which are used for generating turbulences with the objective that the medium to be cooled flows over the entire surface of the base plate12and thus achieves a large heat contact with the cooling medium.

As can be seen fromFIG. 3b, said passage10is stamped out from the material of the base plate12of the elongated plate6in the outward direction using a stamping process.

In the embodiment shown in theFIGS. 3aand 3b, the dome10or the passage10is at least partially integrated in the rim7of the plate6, namely in the region of an outer wall of the dome10or the passage10, which outer wall is not described in detail here and which extends along the edge of the plate6. In the example ofFIG. 3, the rim7and the outer wall of the passage10project from different sides of the plate6so that the passage10, in the region of its outer wall, forms an integral extension of the rim7.

FIG. 4shows a similar arrangement of the elongated plate6which is used for a stacked plate heat exchanger with air cooling. The elongated plate6likewise consists of a base plate12which has an oval shape and is surrounded by a boundary7. The two through holes8a,8bextending at the ends of the elongated plate6are in each case surrounded along their semicircle radius by a passage10a,10b. Here too, the passages10a,10bhave elongated holes13for transporting the coolant. In contrast toFIG. 3, the passage10a,10bis formed inward, which means that the base plate12of the elongated plate6is formed in a higher plane than the elongated holes13of the passage10a,10b. As can be seen fromFIG. 4b, thus, there is a step15between the base plate12and the outer edge of the surface of the passage8a,8b.

FIGS. 4aand 4bshow in particular an embodiment in which the base plate12of the plate6lies in a first plane which is not described in detail here and which, viewed in the stacking direction, lies between a second plane, which is not described in detail here and in which the respective through hole8aor8blies, and a third plane which is not described in detail here and in which the elongated holes13lie. This results in an extremely rigid, multi-stepped structure for the plate6in the region of the elongated holes13.

FIGS. 5 and 6illustrate a comparable arrangement for a stacked plate heat exchanger which is cooled with oil. The elongated plate1is formed in a rectangle-like manner and has rounded corners, wherein this base plate14too is completely surrounded by a boundary2. In the corners of the base plate14, four through holes3a-3dare arranged, two opposing through holes3b,3cof which are arranged along a longitudinal side of the base plate14and have in each case one passage4a,4b(FIG.5aand5c). As shown inFIG. 5b, there is a step15in that the base plate14leaves the normal plane and transitions with the passage4ainto a plane thereabove. In this embodiment, each through hole3ato3dextends completely into the edge region of the base plate14and is directly enclosed there by the boundary2. The passage4a,4bcompletely encloses the through holes3b,3c, wherein a part of the passage4a,4bis integrated in the boundary2.

FIG. 6illustrates a plate1for the stacked plate heat exchanger with oil cooling, wherein the passage4a,4bis directed inward. The two passages4a,4bare arranged opposing each other toward the inside of the base plate14. As illustrated in theFIGS. 6band 6c, the plane spanned by the base plate14is higher than the plane in which the through hole3b,3clies.

FIG. 7illustrates cut-outs from the elongated plate6of the stacked plate heat exchanger which is cooled with air.FIG. 7ashows an inwardly embossed passage10whileFIG. 7billustrates an outwardly extending passage10. It is apparent from the marked regions that a step15between the boundary7of the base plate12and the passage10occurs in each case at the point where the base plate12transitions into the passage8. As illustrated inFIG. 8, such a step15involves the problem that a gap16occurs when soldering a plurality of plates6lying on top of one another. This gap16is clearly visible in particular inFIG. 8. In order to prevent such a gap16in the soldering joint and to configure the stacked plate heat exchanger in a particularly tightly sealed manner, a segment17with an angle which is approximately 5° steeper than the angle at which the passage10is inclined toward the elongated holes13is inserted at the height of the transition of the passage10into the base plate12. Through this clearance of the surface in the inward direction to the base plate12, optimal soldering of two plates6lying on top of one another is achieved because in this manner, a circumferential contact between the soldering surface and the plate6is obtained. The direct contact is uniform everywhere (FIG. 9).

The circumferential direct contact of the plate6with the soldering surface is illustrated again inFIG. 10for a stacked plate heat exchanger with a plurality of plates6lying on top of one another. Here, a circumferential channel18is created between two plates6lying on top of one another. In order to seal this circumferential channel18and to prevent coolant from leaking from said channel18, a cam19is placed in the radius region of the semicircular passage10, in particular near the two ends of a passage10. Said cam19is located at the outer edge of the last elongated hole13of the passage10, wherein the cam19is at an angle perpendicular to the base plate12, which angle is larger than the angle of the outside of passage10to the base plate12. Said cam19is approximately 5 mm wide and is arranged approximately at the radial end of the wall of the passage10near the segment17(seeFIGS. 11aandb).

FIGS. 11cand 11dshow the arrangement of the cam19in a section through a plurality of plates6of the stacked plate heat exchanger stacked on top of one another. The cam19is positioned in the region of the boundary7of the elongated plate6and is at an obtuse angle thereto. When placing the plates6on top of one another, said plates are positioned such that the passages10of in each case two adjoining plates6lie on top of one another.

FIG. 12also illustrates plates6of the stacked plate heat exchanger stacked on top of one another in a cross-section. The second angle of 5°, which is determined by the segment17, leads to a circumferential channel18(FIG. 12) which is completely sealed by the cam19(FIG. 12).

The individual elongated plates1,6of the stacked plate heat exchanger are made from a solderable aluminum and form with the described embodiments a compact heat exchanger which has a high power-to-volume ratio resulting in a maximum degree of heat transfer between the medium to be cooled and the coolant. The compact configuration of the heat exchanger results in a reduction of material consumption during the production. Moreover, a lower forming degree is required which leads to a cost-effective solution. A reliable soldering process due to a circumferential soldering surface is possible without steps so that a tightly sealed heat exchanger is generated.