Patent Application
20180292138
This application is based on and incorporates herein by reference Great Britain Patent Application No. 1705510.4 filed on Apr. 5, 2017.
The present disclosure relates to a manifold for a heat exchanger.
Heat exchanger assemblies are known in which there are two or more heat exchange cores connected together. The cores are multi-pass cores used on a multi-flow type condenser. A baffle is provided between the heat exchangers of the assembly, but there can be leakage across the baffle. Leakage of oil from an oil cooler into a fuel circuit is a problem, from the point of view of emissions.
According to at least one embodiment, there is provided a manifold for a heat exchanger with more than one core. The manifold includes a first tubular manifold part and a second tubular manifold part. Ends of the first and second manifold parts are connected through a baffle which is arranged to block tubular openings of the ends. The baffle substantially separates the ends of the first and second manifold parts. The cross-section of the baffle is larger than the end of the first manifold part to which the baffle is connected and larger than the cross-section of the end of the second manifold part to which the baffle is connected. The baffle includes an axially extending rim in each axial direction which extends over the end of the manifold part. The baffle includes a shoulder to lie inside the bore of the first manifold part and includes a second shoulder to lie inside the bore of the second manifold part. The shoulder and rim define a channel therebetween, the channel receiving the end of the manifold part. In this way, leakage from between one of the manifold parts and the baffle into another manifold part can be limited.
The disclosure, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings, in which:
In order to assemble the heat exchanger 10, the tubes and fins making up the core 14 are assembled in the jig of a build machine (not shown). A manifold 12 is then offered up to the core 14 so that the ends of the tubes 16 are received in the slots 18 of the manifold 12. Once both manifolds 12 are in place, the assembled heat exchanger is heated in order to create a brazed joint between the manifolds 12 and the tubes 16.
The first embodiment of the disclosure is shown in
Each manifold 12 of the heat exchanger 10 of the first embodiment is made up of two tubular manifold parts 30, 32 connected through a baffle 34. Each tubular manifold part 30, 32 is an aluminium profile with aluminium alloy cladding on the outside, and a series of equally spaced slots 18.
The baffle 36 is a unitary part made of aluminium and may be made by drop forging and finished by machining. As best seen in
On each side of the circular disc main body 38 is provided a shoulder 50. The shoulder 50 is a wall of constant height which follows the circumference of the disc 38, spaced just inwardly of the circumference. The wall terminates in positions 52 on the diameter of the disc 38 equidistant from the wall 42 of the slot 40.
The major surface 54 of the disc 38 within the shoulder 50 is dished, the dish 54 being concentric with the centre of the disc 38.
The diameter of the disc 38 of the baffle 34 is the same as the diameter of the tubular manifold parts 30, 32.
To assemble the heat exchanger, tubes and fins are arranged in the build machine jig.
One shoulder 50 of the baffle 34 is inserted into the end 24 of the first tubular manifold part 30. The shoulder 50 is an interference fit in the bore 22 of the manifold part 30. The other shoulder 50 of the baffle 34 is then inserted into the end 24 of the bore 22 of the other manifold part 32. The bores 22 of the first and second manifold parts 30, 32 are examples of tubular openings blocked by the baffle 34. The shoulders 50 provide support to the manifold parts 30, 32. The manifold parts 30, 32 and baffle 34 are assembled so that the slots 18 in the manifold parts 30, 32 and the slot 40 in the baffle 34 form a continuous series with all of the slots 18, 40 being equally spaced. The assembled manifold 12 is then offered up to the core 14 so that the ends of the tubes 16 are received in the slots 18 in the manifold parts 30, 32. The end of one of the tubes 16 is received in the slot 40 in the baffle 34. As mentioned, in the assembled manifold 12, the row of slots, comprising the series of slots 18 in the first manifold part, the slot 40 in the baffle and the slots 18 in the second manifold part 32 form a series of slots which are all equally spaced. In this way, no special measures have to be taken when assembling the tube and the fin core 14 in the jig of the build machine. The core 14 can be assembled in exactly the same way as for the heat exchanger of
Once the heat exchanger 10 has been assembled, it is heated in order to soften or melt the cladding material to create braze joints between the tubes 16 and the manifold parts 30, 32 and also between the baffle 34 and the tube 16 received in the slot 40. The brazing operation will also braze the manifold parts 30, 32 to the baffle 34.
It is thus seen that the heat exchanger 10 is in effect two heat exchangers with two cores as, looking at
As shown in
The tube 16 which is received in the slots 40 of the baffles 34 of the heat exchanger does not receive any heat exchange fluid, but will provide thermal cycle fatigue resistance, reducing the thermal gradient across the two cores.
In a variant on this embodiment, braze paste may be applied to the outer surface 56 of the shoulder 50. In this way, the shoulder 50 will braze to the inside surface 22 of the manifold parts 30, 32. As an alternative to the use of braze paste, a braze ring may be used. As a further alternative, each manifold part 30, 32 may be double clad, so that it is clad on both its inner surface 22 as well as its outer surface 44 and in that way will braze to the shoulder 50. In a further variant, the shoulder 50 is not an interference fit in the bore 22 of the manifold parts 30, 32. In that case, the parts of the manifold may be held together by tack welding the baffle 34 to the manifold parts 30, 32.
The baffle 34 of the second embodiment does not include a slot 40. Because the slot 40 is not provided, the tube 16 adjacent the baffles 34 has to be shorter than the other tubes, which means that extra care is needed in setting up the core 14 in the build machine in order to ensure that a shorter tube is in place, and that it is in the right location with respect to the location of the baffle along the manifold. Rather than the short tube, a blanking plate 58 can be used.
The baffle 34 of the third embodiment is the same as the baffle of the first embodiment except that in this case the main body disc 38 of the baffle 34 is of greater diameter than the manifold parts 30, 32 and includes a rim 64 extending axially all around the circumference in both axial directions. The rim 64 and shoulder 50 define between them a channel 66 to receive the end of a manifold part 30, 32. This increases the strength of the joint between the baffle 34 and the manifold parts 30, 32 prior to brazing. It also means that the inner wall 68 of the rim 64 is in direct contact with the clad outer surface of the manifold part 30, 32 so that a good brazed joint can be formed between the baffle 34 and the manifold part 30, 32. Braze paste may also be used on the shoulder 50 to provide a good, robust, leak free construction.
In the fourth embodiment, the slot 40 in the baffle 34 is wider so that the tube 16 received in the slot 40 does not touch the walls of the slot 40 and therefore does not braze to them. In this case, the tube 16 in the slots 40 will be unsupported, thus allowing it to expand and contract freely, thereby reducing the thermal stress on the two adjacent tubes of the core 14. This will increase the thermal cycle durability.
In a further variant, the baffle 34 may include two slots 40 to receive the ends of two adjacent tubes 16 of the core. This will improve the thermal cycle durability.
In a further variant, one or more additional manifold parts may be connected through one or more additional baffles 34 in order to provide a heat exchanger with three or more cores.
By means of the disclosure, a single heat exchanger with multiple cores can be built as one core on a core build machine rather than making two separate cores which are joined at a later stage. The baffle 34 prevents fluid bypass from one manifold part 30 to the next.
According to one aspect of the disclosure there is provided a manifold for a heat exchanger with more than one core, the manifold comprising a first tubular manifold part and a second tubular manifold part, the ends of the first and second manifold parts being connected through a baffle which is arranged to block the tubular openings, the baffle substantially separating the ends of the first and second manifold parts, wherein the cross-section of the baffle is larger than the end of the first manifold part to which it is connected and larger than the cross-section of the end of the second manifold part to which it is connected, and the baffle includes an axially extending rim in each axial direction which extends over the end of a manifold part and the baffle includes a shoulder to lie inside the bore of the first manifold part and includes a second shoulder to lie inside the bore of the second manifold part, wherein the shoulder and rim define a channel therebetween, the channel receiving the end of the manifold part.
In this way, any leakage between one of the manifold parts and the baffle will be to atmosphere, rather than into the other manifold part.
The shoulder may extend around at least a quarter of the periphery of the baffle, or at least a third of the periphery. The shoulder may extend over no more than two thirds of the periphery or may extend over a half or less of the periphery. In a particular embodiment, the shoulder may extend over half of the periphery of the baffle.
The baffle may be attached to each of the tubular manifold pads. The baffle may be attached by welds, such as tack welds, or may be attached by brazed connections. Where the contact between each manifold part and the baffle does not include a clad surface, the braze connection may be through braze paste applied to one of the contact surfaces.
The manifold may be a manifold for a tube and fin heat exchanger core and each manifold part may therefore include a series of slots to receive tubes. The slots may be equally spaced along the length of the manifold. This makes it easier to assemble a heat exchanger including the manifold on a build machine, as a uniform, regularly arranged set of tubes and fins can be mounted in the building machine jig and the manifold can then be offered up to receive the ends of the tubes in the slots. No change in the set up of the tubes or arrangement of the tubes is necessary in order to take account of the position of the baffle. In one embodiment, this can be achieved by defining a slot in the baffle. The tube in the baffle slot would not have any fluid flow or perform any function of heat exchange. The tube in the baffle slot acts as a thermal barrier reducing the thermal gradient between the two adjacent cores. In an alternative embodiment, the baffle slot is sufficiently wide that the tube does not touch or braze to the baffle. In this way, the tube in the baffle slot will be able to expand and contract freely, further reducing thermal stress on the two adjacent tubes, which will increase thermal cycle durability.
Each manifold part may include braze cladding on its outer surface.
The baffle may be made in any suitable way, such as machining from solid, or casting, but may be forged.
The manifold may include a third tubular manifold part, the ends of the second manifold part and third manifold part being connected through a baffle which is arranged to block the tubular openings, the baffle substantially separating the ends of the second and third manifold parts.
The baffle may be a baffle including any or none of the features as described above.
According to another aspect of the disclosure there is provided a heat exchanger assembly including two heat exchange cores and a manifold according to the preceding aspect of the disclosure.
According to another aspect of the disclosure there is provided a method of assembling a heat exchanger for assembly for brazing, the method comprising: arranging tubes and fins in a build machine jig, assembling a manifold according to the first aspect of the disclosure by attaching the first manifold part to the baffle and attaching the second manifold part to the baffle; offering up the manifold to the cores so that the tubes are received in the slots in the manifold parts; heating the assembly to braze the parts together.
The baffle may be attached to the manifold parts in any suitable way prior to brazing. In one embodiment, the baffle may be an interference fit in the end of each manifold part. In another embodiment, the baffle may be tack welded to the manifold parts.
The method may include the step of applying braze paste to each shoulder so that the braze paste is sandwiched between the shoulder and the manifold part and creates a brazed joint between the shoulder and manifold parts after heating and cooling. In an alternative embodiment, the method may include inserting a braze ring between the baffle and each manifold part. In a further embodiment, each manifold part may be double clad, so that it includes braze cladding on both its inner and outer surfaces.
In the step of offering up the manifold to the tubes, the tubes may be inserted into the slots to a limited distance such that a gap is left between the ends of the tubes and the shoulders of the baffle.
According to a further aspect of the disclosure there is provided a manifold for a heat exchanger with more than one core, the manifold comprising a first tubular manifold part and a second tubular manifold part, the ends of the first and second manifold parts being connected through a baffle which is arranged to block the tubular openings, the cross-section of the baffle being larger than the cross-sections of the tubular openings at the ends of the first and second manifold parts.
The present disclosure may be summarized as follows. A manifold for a heat exchanger with more than one core may include a first tubular manifold part and a second tubular manifold part. The ends of the first and second manifold parts may be connected through a baffle. The baffle may be arranged to block the tubular openings. The baffle may substantially separate the ends of the first and second manifold parts.
The cross-section of the baffle may be larger than the cross-sections of the tubular openings at the ends of the first and second manifold parts. The cross-section of the baffle may be the same as the end of the first manifold part to which it is connected and the same as the cross-section of the end of the second manifold part to which it is connected. The cross-section of the baffle may be larger than the end of the first manifold part to which it is connected and larger than the cross-section of the end of the second manifold part to which it is connected. The baffle may include an axially extending rim in each axial direction which extends over the end of a manifold part. The baffle may include a shoulder to lie inside the bore of the first manifold part and include a second shoulder to lie inside the bore of the second manifold part. The shoulder may extend around at least a quarter of the periphery of the baffle. The shoulder may extend around at least a third of the periphery of the baffle. The shoulder may extend over no more than two thirds of the periphery of the baffle. The shoulder may extend over a half or less of the periphery. The shoulder may extend over half of the periphery of the baffle. The shoulder and rim may define a channel therebetween, and the channel may receive the end of the manifold part. The baffle may be attached to each of the tubular manifold parts. The baffle may be attached to each of the tubular manifold parts through braze paste applied to one of the contact surfaces. The manifold may be a manifold for a tube and fin heat exchanger core and each manifold part includes a series of slots to receive tubes. The slots may be equally spaced along the length of the manifold. The baffle may define a tube receiving slot. A body of the baffle between the ends of the first and second manifold parts may be solid. The baffle may be forged. The manifold may include a third tubular manifold part. The ends of the second manifold part and third manifold part may be connected through a baffle which is arranged to block the tubular openings. The baffle may substantially separate the ends of the first and second manifold parts. A heat exchanger assembly may include two heat exchange cores and the above-described manifold. The heat exchange cores may be tube and fin cores. The baffle may define a tube receiving slot. The walls of the baffle slot may be brazed to the end of the tube. The baffle slot may be sufficiently wide that the tube does not touch or braze to the walls of the baffle slot. The body of the baffle between the ends of the first and second manifold parts may be solid, a blank plate or a tube which is shorter than the other tubes of the core may be positioned opposite the baffle. Each manifold part may be double clad, so that it includes braze cladding on both its inner and outer surfaces.
A method of assembling a heat exchanger for assembly for brazing may include: arranging tubes and fins in a build machine jig; attaching a first manifold part to a baffle and attaching a second manifold part to a baffle, so that the baffle blocks the tubular opening at one end of each manifold part, the baffle substantially separating the ends of the first and second manifold parts; offering up the manifold, being comprised of the two manifold parts and the baffle, to the tubes and fins so that the tubes are received in the slots in the manifold parts; and heating the assembly to braze the components together.
Another method of assembling a heat exchanger for assembly for brazing may include: arranging tubes and fins in a build machine jig; assembling the above-described manifold by attaching the first manifold part to the baffle and attaching the second manifold part to the baffle; offering up the manifold to the tubes and fins so that the tubes are received in the slots in the manifold parts; and heating the assembly to braze the components together.
In the methods, the baffle may be attached to the manifold parts by the baffle being an interference fit in the end of each manifold part. In the methods, the baffle may be attached to the manifold parts by tack welding the baffle to the manifold parts. In the methods, the method may include inserting a braze ring between the baffle and each manifold part. In the methods, the baffle may include a shoulder to lie inside the bore of the first manifold part and includes a second shoulder to lie inside the bore of the second manifold part. The methods may include the step of applying braze paste to each shoulder prior to attaching the manifold parts to the baffle so that the braze paste is sandwiched between the shoulder and the manifold part and creates a brazed joint between the shoulder and manifold parts after heating. In the step of offering up the manifold to the tubes in the methods, the tubes may be inserted into the slots to a limited distance such that a gap is left between the ends of the tubes and the shoulders of the baffle.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1705510.4 | Apr 2017 | GB | national |
