GB2527494B

GB2527494B - A heat exchanger assembly

Info

Publication number: GB2527494B
Application number: GB1408717.5A
Authority: GB
Inventors: Lenczewski Daniel; Turnbull Jonathan; Timmins Martin
Original assignee: Denso Marston Ltd; Denso Corp
Current assignee: Denso Marston Ltd; Denso Corp
Priority date: 2014-05-16
Filing date: 2014-05-16
Publication date: 2019-09-04
Anticipated expiration: 2034-05-16
Also published as: GB2527494A; GB201408717D0

Description

A Heat Exchanger Assembly

The invention relates to a heat exchanger assembly. A known heat exchanger assembly 10, sometimes known as a "combined cooler" or "combi cooler", is shown in Figs 1 and 2 and comprises two heat exchangers 12, 14, in this case oil coolers, mounted end to end through two splitter plates 16, 18. The heat exchangers 12, 14 are plate and fin heat exchangers. The heat exchangers 12, 14 ) and splitter plates 16, 18 are made of aluminium alloy and are brazed together. A combi cooler is able to replace two separate heat exchangers of the same construction. As such the design is more cost effective and requires less space. This system enables modular production so that a module, being a single heat exchanger, i can be used by itself or made into a combi cooler, thus manufacturing efficiency is improved.

During build of a combi cooler 10, the coolers 12, 14 and splitter plates 16, 18 are assembled in a jig for brazing. Once the first cooler 12 has been placed in the build ) stack, the first splitter plate 16 is added. Each cooler 12, 14 is made up of gallery plates 20 and fins 22. Each gallery plate 20 includes a drawn cup feature 24 at each end which separates the gallery plates 20 and provides space for the external fin 22 between the gallery plates 20. The drawn cup 24 includes an aperture for cooling fluid flow through the cooler 12, 14. Each splitter plate 16, 18 is generally flat but at i each end also includes a drawn cup 26 to provide space between the splitter plate 16, 18 and the adjacent gallery plate 20 but no aperture as it provides a seal for the aperture in the adjacent gallery plate 20 between the inner fluid and outside environment. ) The gallery plate 20 can be incorrectly aligned on the splitter plate 16, 18 and movement can occur resulting in a local failure mode.

When the two heat exchangers 12, 14 with the splitter plates 16, 18 between them are assembled in the jig, pressure is applied vertically through the ends of the assembly 10. Each splitter plate 16, 18 is a composite of different aluminium alloys, having a higher melting point base alloy in the centre and lower melting point braze alloys on i the outside. During brazing in the jig, the combi cooler 10 will reach a temperature of around 590°C, at which point the base alloy remains solid but with very little mechanical strength remaining, and the braze alloy melts. As the cooler 10 is brazed in a vertical position the cups 26 at the ends of the splitter plates 16, 18 can sag due to the combi cooler build stack weight and the force from the braze jig compression. ) The braze jig, applying compression over the whole core is required to ensure good braze contact throughout the core. Sagging of the splitter plates 16, 18 can cause (i) a leak between the splitter plate 16, 18 and the adjoining gallery plate 20, (ii) movement of the splitter plate 16, 18 resulting in scrap product and (iii) and variability in the final dimension of the core stack height. This leads to downstream assembly i problems when assembling the oil cooler in a later stage of manufacture. TW M 405557U1 relates to a heat exchanger of the cross flow type. Each gallery plate is covered with dimples. No splitter plate is disclosed. ) According to the invention there is provided a heat exchanger assembly comprising two heat exchangers mounted end to end through two splitter plates, each splitter plate including a cup at least at one end of each splitter plate, the cups facing one another to define a cavity therebetween, at least one cup including at least one protrusion into the cavity in the direction of connection of the heat exchangers, the or each protrusion of i one cup being arranged to contact the other cup to thereby provide support across the cavity.

In this way, the or each protrusion acts to resist sag of each cup. ) In a preferred embodiment there is a cup at least at each end of each splitter plate.

Each cup may include at least one said protrusion and the protrusions in facing cups are preferably arranged to contact one another. While each cup may include a plurality oi protrusions, in a preierrea emDoaiment eacn cup includes a single protrusion. The or each protrusion may be a dimple. The dimple may be a round dimple, which may be generally hemispherical, or in a preferred embodiment the protrusion is elongate, for example in a direction transverse to an elongate direction of 5 the splitter plate. The contact area between the dimples may be 10 to 30 mm2. In the case of a round dimple, the contact area may be in the range 10 to 20 mm2. In the case of an elongate dimple, the contact area is preferably 20 to 30 mm2.

Preferably, the or each cup, including the or each protrusion thereof, is continuous. ) As the cup is not perforated, it is stronger.

In a preferred embodiment, the two splitter plates are the same. This facilitates manufacture of the splitter plate. In use, one will be turned through 180° with respect to the other so that the cups face each other.

Each splitter plate preferably includes a filler metal layer and each protrusion of one cup is brazed to the other cup.

The heat exchangers may take any suitable form, but in a preferred embodiment the ) heat exchangers are plate and fin heat exchangers. In that case, a fin may be provided between the splitter plate and the adjacent heat exchanger plate.

Each heat exchanger may be a heat exchanger, wherein each heat exchanger plate is a gallery plate, each gallery plate including a cup at each end, each cup having a floor 5 with an aperture in the floor defined by an edge. Each splitter plate may include at least one locating projection which is received in the aperture of the adjacent gallery plate to engage the edge of the aperture to thereby locate the splitter plate on the gallery plate of the heat exchanger. In this way, misalignment between the splitter plate and the adjacent gallery plate is minimised. )

In this way, the splitter plates are held in place with respect to the heat exchangers. mere may oe a single locating projection, out in a prererrea emooaiment mere are at least two locating projections. Where the aperture in the gallery plate is elongate, there may be at least one projection at each end of the aperture. There may be at least three projections and in a preferred embodiment there are four projections. In i particular where the aperture in the gallery plate is elongate, there may be two projections at one end and two projections at the other, for example, in a rectangular array, each projection engaging the edge of the aperture of the heat exchanger.

Preferably each splitter plate includes at least two locating projections, so that at least ) one locating projection is received in each of the apertures of the adjacent gallery plate. In this way, the splitter plate is located on the gallery plate at each end and so is more securely located.

Each splitter plate preferably includes a filler metal layer and each projection is i preferably brazed to the edge of the gallery plate aperture.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: ) Fig 1 is a perspective view of a prior known combi cooler;

Fig 2 is a detail view of the central region of the known combi cooler of Fig 1;

Fig 3 is a perspective detail view from underneath of one end of a splitter plate in a first embodiment of the invention;

Fig 4 is a perspective detail view from above of the end of the splitter plate of Fig 3; i Fig 5 is a perspective detail view of two splitter plates of the first embodiment brazed together;

Fig 6 is a plan view of a splitter plate of the first embodiment;

Fig 7 is a perspective view of a splitter plate from one side;

Fig 8 is a perspective view of the splitter plate from the other side; ) rig y is a perspective detail view rrom aoove or tne sputter piate or tne nrst embodiment with a gallery plate of a heat exchanger arranged on top of it; Fig 10 is a plan view of the arrangement of Fig 9;

Fig 11 is a detail perspective view of the central region of a combi cooler using the i splitter plates of the first embodiment;

Fig 12 is the view of Fig 11, exploded;

Fig 13 is a perspective view of the heat exchanger assembly of the first embodiment;

Fig 14 is a perspective detail view from above of one end of a splitter plate in a second embodiment of the invention; ) Fig 15 is a perspective detail view from underneath of the end of the splitter plate of

Fig 14;

Fig 16 is a perspective detail view of two splitter plates of the second embodiment brazed together;

Fig 17 is a perspective detail view from above of one end of a splitter plate in a third i embodiment of the invention;

Fig 18 is a perspective detail view from underneath of the end of the splitter plate of

Fig 17.

The first embodiment is shown in Figures 3 to 13 and is a development of the known ) combi cooler described above in relation to Figures 1 and 2. Thus, the combi cooler 10 of the invention comprises two heat exchangers 12, 14 mounted end to end through splitter plates 16, 18. The heat exchangers 12, 14 are plate and fin heat exchangers.

The heat exchangers 12, 14 and splitter plates 16, 18 are made of aluminium and are brazed together. Each splitter plate 16, 18 of the first embodiment is generally an i elongate flat strip but each end includes a generally flat depressed section 28 forming a cup 26 which is open to the end of the strip and which is bounded on three sides by walls 30, 32, 34.

Each splitter plate 16, 18 is made from a flat strip of aluminium alloy material. Each ) strip is pressed in a press tool to form the cup 26.

The combi cooler 10 of the first embodiment is intended for heavy duty applications such as in an off highway vehicle and might weigh 5 to 30kg.

In the first embodiment, unlike in the known heat exchanger 10, the depressed section 28 of the splitter plates 16, 18 is not completely flat, but includes a central protrusion in the form of a hemispherical support dimple 36 which is as tall as the walls 30, 32, 5 34. Four locating projections 38, 40, also in the form of dimples, project downwardly from the section 28. The small, locating dimples 38, 40 are arranged in a rectangular array, with two each side of the central support dimple 36, the two locating dimples 38 on one side being approximately equidistant between the central dimple 36 and the wall 30, and the two locating dimples 40 on the other side being equidistant between ) the central dimple 36 and the side wall 34.

In use, the heat exchangers 12, 14 are assembled in a jig for brazing. The gallery plates 20 and fins 22 of the lower heat exchanger 14 are assembled in the jig and then the lower splitter plate 18 is added to the stack, with the cup 26 facing upwards. The i other splitter plate 16 is arranged in the opposite orientation, with the cup 26 at each end facing downwards, and is added to the stack. The next gallery plate 20 is then added. This situation is shown in Figures 9 and 10. The gallery plate 20, in known fashion, includes a cup 24 at each end. In the floor of the cup 24 is an aperture defined by an edge 42 which is generally racetrack shaped having rounded ends 44 ) and straight sides 46. Each locating dimple 38, 40 engages the edge 42 of the aperture in the cup 24 to locate the gallery plate 20 on the splitter plate 16. Each locating dimple 38, 40, engages the rounded side 44 of the edge 42 just before it meets the straight sided part 46. 5 In this way, the locating dimples 38, 40 locate the gallery plate 20 on the splitter plate 16 so that the parts are aligned. This prevents weakness that would result from misalignment, and also prevents the gallery plate 20 becoming so misaligned with the splitter plate 16 that the depressed section 28 no longer covers the whole of the aperture defined by edge 42, resulting in a leak in the heat exchanger 10. )

The arrangement is the same at the other end of the gallery plate 20 and splitter plate 16 and is also the same between the splitter plate 18 and the adjacent gallery plate 20 below it.

As seen in Figures 11 and 12, when the splitter plates 16, 18 are arranged with their cups 26 facing one another, and brought together in the stack, the tops of the support dimples 36 contact one another. A hemisphere is a strong shape, and the central i structure formed by the contacting support dimples 36 form a support in the centre of the cavity 48 formed by the cups 26. When pressure is exerted on the jig during brazing, the contacting support dimples 36 will prevent the cups 26 of the splitter plates 16, 18 from sagging. It can be seen that if the flat section 28 should bow, a leak path might be created into the aperture defined by edge 42 in the gallery plate 20. The ) support dimples 36 prevent this.

During brazing, the filler material on the surfaces of the splitter plates 16, 18 will ensure that the splitter plates 16, 18 are brazed together, and that each splitter plate 16, 18 is brazed to the adjacent gallery plate 20. In particular, the support dimples 36 will i be brazed together at their contacting ends, forming a strong integrated structure. The contact area of the two support dimples 36 may be about 13mm2. Also, the locating dimples 38, 40 will be brazed to the edge 42 of the aperture in the gallery plate 20 to make a strong connection there. ) It is seen that each splitter plate 16, 18 is a continuous part, with no perforations or other discontinuities. This makes the splitter plates 16, 18 strong and also removes any opportunity for leakage. A second embodiment of the invention will now be described. The second > embodiment is similar to the first and only the differences from the first embodiment will be described. The same reference numerals will be used for equivalent features. The second embodiment is shown in Figures 14, 15 and 16.

In the second embodiment, the support dimple 36 is elongate in a direction transverse ) to the elongate direction of the splitter plates 16, 18. in mis way, tne area or contact oetween tnese two support aimpies jo is larger, providing a stronger support. The contact area of the two elongated dimples in the second embodiment may be about 23mm2. i The third embodiment is shown in Figures 17 and 18. The third embodiment is similar to the first embodiment and only the differences from the first embodiment will be described. The same reference numerals are used for equivalent features.

In the third embodiment, each pair of locating dimples 38, 40 on each side of the ) support dimple 36 is replaced by a single long trench 50, 52. Thus, one trench 50 lies between the support dimple 36 and side wall 30 while on the other side of the support dimple 36, the trench 52 lies between the support dimple 36 and side wall 34. The elongate axis of each trench 50, 52 is parallel to the elongate axis of the splitter plate 16, 18.

In this way, only two features, namely the trenches 50, 52 have to be pressed, instead of the four locating dimples 38, 40.

Each gallery plate 20 may be made of 1.2 mm thick aluminium alloy, and each splitter ) plate 16, 18 may be made of 2mm thick aluminium alloy.

Naturally, the trench shaped locating dimples of the third embodiment can be used with the elongate support dimple of the second embodiment in a variation. )

Claims

ciaims

1. A heat exchanger assembly comprising two heat exchangers mounted end to end through two splitter plates, each splitter plate including a cup at least at one end of 5 each splitter plate, the cups facing one another to define a cavity therebetween, at least one cup including at least one protrusion into the cavity in the direction of connection of the heat exchangers, the or each protrusion of one cup being arranged to contact the other cup to thereby provide support across the cavity. )

2. A heat exchanger assembly as claimed in claim 1, wherein the contact area between the protrusion or protrusions of one cup and the other cup is in the range 10 to 30 mm2.

3. A heat exchanger assembly as claimed in claim 1 or claim 2, wherein there is a 5 cup at least at each end of each splitter plate.

4. A heat exchanger assembly as claimed in claim 1, 2 or 3, wherein each cup includes at least one said protrusion. )

5. A heat exchanger assembly as claimed in claim 4, wherein the protrusions in facing cups are arranged to contact one another.

6. A heat exchanger assembly as claimed in any preceding claim, wherein each cup includes a single protrusion.

7. A heat exchanger assembly as claimed in claim 6, wherein the protrusion is arranged substantially centrally in the cup.

8. A heat exchanger assembly as claimed in any preceding claim, wherein the or ) each protrusion is a dimple.

9. A heat exchanger assembly as claimed in claim 8, wherein the or each dimple is a round dimple.

10. A heat exchanger assembly as claimed in claim 8 or claim 9, wherein the contact area between the dimples is in the range 10 to 20 mm2 5

11. A heat exchanger assembly as claimed in any of claims 1 to 8, wherein the or each protrusion is elongate.

12. A heat exchanger assembly as claimed in claim 11, wherein each splitter plate has an elongate direction, and wherein the or each protrusion is elongate in a direction ) transverse to the elongate direction of the splitter plate.

13. A heat exchanger assembly as claimed in claim 11 or claim 12, wherein the contact area between the protrusions is 20 to 30mm2. 5

14. A heat exchanger assembly as claimed in any preceding claim, wherein the or each cup, including any or each protrusion thereof, is continuous.

15. A heat exchanger assembly as claimed in any preceding claim, wherein the two splitter plates are the same. )

16. A heat exchanger assembly as claimed in any preceding claim, wherein each splitter plate includes a filler metal layer and the or each protrusion of one cup is brazed to the other cup. 5

17. A heat exchanger assembly as claimed in any preceding claim, wherein the heat exchangers are plate and fin heat exchangers.

18. A heat exchanger assembly as claimed in claim 17, wherein a fin is provided between each splitter plate and the adjacent heat exchanger plate. )

19. A heat exchanger assembly as claimed in any preceding claim, wherein each heat exchanger plate is a gallery plate, each gallery plate including a cup at each end, eacn cup naving a noor wim an aperture in me noor aennea ny an eage, ana wnerein each splitter plate includes at least one locating projection which is received in the said aperture of the adjacent gallery plate to engage the said edge of the aperture to thereby locate the splitter plate on the gallery plate of the heat exchanger.

20. A heat exchanger assembly as claimed in claim 19, wherein there are at least two locating projections.

21. A heat exchanger assembly as claimed in claim 19 or claim 20, wherein the ) aperture in the gallery plate is elongate, and there is at least one locating projection at each end of the aperture.

22. A heat exchanger assembly as claimed in claim 20 or claim 21, wherein each locating projection is elongate in the elongate direction of the splitter plate and each 5 end of each locating projection is arranged to engage the edge of the aperture.

23. A heat exchanger assembly as claimed in any of claims 19 to 22, wherein there are at least three locating projections. )

24. A heat exchanger assembly as claimed in any of claims 19 to 23, wherein there are four projections.

25. A heat exchanger assembly as claimed in claim 24, wherein the aperture in the gallery plate is elongate, and there are two projections at one end and two projections 5 at the other, each projection engaging the edge of the aperture of the heat exchanger.

26. A heat exchanger assembly as claimed in any of claims 19 to 25, wherein each splitter plate includes at least two locating projections, arranged so that at least one locating projection is received in each of the apertures of the adjacent gallery plate. )

27. A heat exchanger assembly as claimed in any of claims 19 to 26, wherein each splitter plate includes a filler metal layer and each locating projection is brazed to the edge of the gallery plate aperture.