EP4015974A1

EP4015974A1 - A manifold for a heat exchanger

Info

Publication number: EP4015974A1
Application number: EP20214343.4A
Authority: EP
Inventors: Mohamed Asri; Benjamin Ferlay; Adil AYAD
Original assignee: Valeo Klimasysteme GmbH
Current assignee: Valeo Klimasysteme GmbH
Priority date: 2020-12-15
Filing date: 2020-12-15
Publication date: 2022-06-22

Abstract

A manifold (100) for a heat exchanger (200) includes a header (110) and a cover (120). The header (110) includes a bottom wall (112) and two sidewalls (114) and (116). Each sidewall (114, 116) has a first section (114a, 116a) with a first thickness "t" and a second section (114b, 116b) with a second thickness "T". The first thickness "t" is smaller than the second thickness "T" and steps (118a) and (118b) formed at interface of the first section (114a, 116a) and the second section (114b, 116b) of the respective side wall (114, 116) are disposed within the inside volume of the manifold (100). The cover (120) includes cover walls (122) and (124) corresponding to the sidewalls (114) and (116) of the header (110) that rests on the respective opposite steps (118a) and (118b).

Description

The present invention relates to a heat exchanger. In particular, the present invention relates to a manifold for the heat exchanger.
A conventional heat exchanger generally includes at least one conventional manifold 10. Each conventional manifold 10 includes a cover 2 and a header 1 joined by brazing to define an enclosure for receiving and holding a first heat exchange fluid therein. The cover 2 includes a first pair of sidewalls 2a and 2b and a fluid inlet 2c for ingress of the first heat exchange fluid into the manifold or a fluid outlet for egress of the first heat exchange fluid out of the manifold, based on whether the manifold is an inlet manifold or an outlet manifold respectively. The header 1 includes a second pair of sidewalls 1a and 1b and a plurality of slots 1c for receiving a plurality of heat exchange tubes 3. The heat exchange tubes 3 establish fluid communication between the inlet manifold and the outlet manifold. The first heat exchange fluid undergoes heat exchange with second heat exchange fluid flowing outside and across the heat exchange tubes, as the first heat exchange fluid flows through the heat exchange tubes connecting and establishing fluid communication between the inlet manifold to the outlet manifold.
The sidewalls 1a and 1b of the header 1 are widely spaced with respect to each other compared to the spacing between the sidewalls 2a and 2b of the cover 2 to receive the respective sidewalls 2a and 2b of the cover 2 there-between. The sidewalls 1a and 1b of the header 1 include sections 1d and 1e respectively of reduced dimension to facilitate crimping between the header 1 and the cover 2, particularly crimping of the sidewalls 1a and 1b of the header 1 over the sidewalls 2a and 2b of the cover 2. The crimping of the sidewalls 1a and 1b of the header 1 over the sidewalls 2a and 2b of the cover 2 is an attempt to position the cover 2 with respect to the header 1 and achieve sufficient contact there between for proper brazing. However, the crimping of the sidewalls 1a and 1b of the header 1 over the sidewalls 2a and 2b of the cover 2 fails to achieve sufficient contact between the sidewalls 1a and 1b of the header 1 and the sidewalls 2a and 2b of the cover 2. Accordingly, the crimping fails to achieve a robust brazing connection between the cover 2 and the header 1. More specifically, there are chances of relative movement, particularly relative angular movement between the cover 2 and the header 1 and misalignment of the cover 2 with respect to the header 1 as the crimping fails to ensure proper positioning of the cover 2 with respect to the header 1.
In case of any misalignment, particularly relative angular movement of the cover 2 with respect to the header 1, at least a portion of the sidewalls 2a and 2b of the cover 2 loses contact with the sidewalls 1a and 1b of the header 1. Accordingly, contact area between surfaces to be brazed, particularly the between the sidewalls 2a and 2b of the cover 2 and the sidewalls 1a and 1b of the header 1 is insufficient for robust brazing connection, thereby detrimentally impacting the brazing connection there-between or causing brazing defects. The problem of misalignment between the cover 2 and the header 1 is more likely to arise during the crimping between the cover 2 and the header 1. The improper brazing connection between the header 1 and the cover 2 due to brazing defects may result in mechanical failure of the manifold and/or leakage of first heat exchange fluid held in the manifold. The leakage of the first heat exchange fluid from the manifold detrimentally affects efficiency and performance of the heat exchanger. The inefficient performance of the heat exchanger may cause thermal seizure of the critical components to be cooled by the heat exchanger. Also misalignment of the cover 2 with respect to be the header 1 provides free space for intrusion of moisture that may cause corrosion in the brazing joint between the cover 2 and the header 1 and the brazing joint between the header 1 and the cover 2 exhibits poor corrosion resistance.
Similarly, the sidewalls 2a and 2b of the cover 2 received inside the header 2 are positioned to prevent over insertion of the heat exchange tubes 3 in the corresponding slots 1c of header 1 to achieve uniform length of all heat exchange tubes 3 inside the manifold 1. The uniform insertion of the heat exchange tubes 3 in the manifold 10 is required for uniform distribution of the first heat exchange fluid from inlet manifold to the heat exchange tubes 3 and uniform collection of first heat exchange fluid from the heat exchange tubes to the outlet manifold. However, in case the cover is misaligned with respect to the header, the sidewalls 2a and 2b of the cover 2 fail to ensure uniform insertion of the heat exchange tubes 3 into the manifold. Accordingly, the first heat exchange fluid is not uniformly distributed from the inlet manifold to the heat exchange tubes and is not uniformly collected into the outlet manifold from the heat exchange tubes. The efficiency and performance of the heat exchanger is detrimentally affected.
There is a need for a manifold that stably positions and firmly holds the cover inside the header, thereby preventing any misalignment of the cover with respect to the header. Further, there is a need for a manifold that prevents brazing defects between the header and the cover due to misalignment and problems such as leakage of first heat exchange fluid from the manifold and mechanical failure arising due to the brazing defects. Further, there is a need for a manifold that prevents over insertion of the heat exchange tubes in the corresponding slots of a header of the manifold to achieve receiving of uniform length of heat exchange tubes inside the manifold. In particular, there is a need for a manifold that achieves uniform distribution of first heat exchange fluid from the inlet manifold to the heat exchange tubes and uniform collection of heat exchange fluid from the heat exchange tubes into the outlet manifold. Furthermore, there is a need for a manifold that prevents free space at brazing joint between a header and a cover and exhibits improved corrosion resistance at the brazing joint between the cover and the header thereof as compared to conventional manifold. Further, there is a need for a manifold that enhances efficiency and performance of the heat exchanger.
An object of the present invention is to provide a manifold for a heat exchanger that stably positions and firmly holds the cover inside the header, thereby preventing misalignment of the cover with respect to the header.
Another object of the present invention is to provide a manifold for a heat exchanger that obviates the drawbacks such as leakage of first heat exchange fluid from the manifold and mechanical failure of the manifold caused by improper brazing caused by misalignment between the header and the cover.
Another object of the present invention is to provide a manifold for a heat exchanger that enhances efficiency and performance of the heat exchanger.
Yet another object of the present invention is to provide a manifold for a heat exchanger that is convenient and quick to manufacture.
Still another object of the present invention is to provide a manifold that can be manufactured without any defect or comparatively fewer defects compared to conventional manifolds, thereby reducing rejection rate.
Another object of the present invention is to provide a manifold for a heat exchanger that achieves uniform distribution of first heat exchange fluid from the inlet manifold to the heat exchange tubes and uniform collection of heat exchange fluid from the heat exchange tubes into the outlet manifold.
Still another object of the present invention is to provide a manifold that exhibits improved corrosion resistance at the brazing joint between a cover and a header thereof as compared to conventional manifold.
In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements, which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.
A manifold for a heat exchanger is disclosed in accordance with an embodiment of the present invention. The manifold includes a header and a cover. The header includes a bottom wall and two sidewalls. Each sidewall has a first section with a first thickness "t" and a second section with a second thickness "T". The first thickness "t" is smaller than the second thickness "T" and steps formed at interface of the first section and the second section of the respective side wall are disposed within the inside volume of the manifold. The cover includes cover walls corresponding to the sidewalls of the header that rests on the respective opposite steps.
Generally, at least one of the steps extends along an entire length of the manifold.
Specifically, the first section of the sidewall includes a corresponding straight portion abutting against a straight portion of the respective cover wall.
Typically, the step supports at least a portion of the thickness "Z" of the respective cover wall.
More specifically, the step supports entire thickness "Z" of the respective cover wall.
Typically, the bottom wall of the header includes a plurality of slots to receive heat exchange tubes therein, the cover walls supported on the respective steps prevent insertion of a section of the respective heat exchanger tube beyond a pre-determined length in the manifold.
In one embodiment, at least a portion of at least one of the cover wall supported on the respective step overhangs and extends beyond the respective step towards an interior of the manifold.
Alternatively, at least one of the cover wall includes protrusion on inner side thereof, extending opposite to the respective first section of the sidewall of the header and towards an interior of the manifold.
Also is disclosed a heat exchanger in accordance with an embodiment of the present invention. The heat exchanger includes at least one manifold in fluid communication with a plurality of heat exchange tubes, wherein the manifold is as disclosed above.
Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

FIG. 1 illustrates a schematic representation of a conventional manifold for a heat exchanger;
FIG. 2a illustrates a schematic representation of a manifold in accordance with an embodiment of the present invention formed by brazing a cover and a header;
FIG. 2b illustrates a schematic representation of the cover of the manifold of FIG. 2a ;
FIG. 2c illustrates a schematic representation of the header of the manifold of FIG. 2a ;
FIG. 3a illustrates a schematic representation of a manifold in accordance with another embodiment of the present invention formed by brazing a cover and a header;
FIG. 3b illustrates a schematic representation of the cover of the manifold of FIG. 3a ;
FIG. 3c illustrates a schematic representation of the header of the manifold of FIG. 3a ; and
FIG 4 illustrates a heat exchanger, wherein the heat exchanger includes a manifold of either FIG. 2a or FIG. 3a.

It must be noted that the figures disclose the invention in a detailed enough way to be implemented, said figures helping to better define the invention if needs be. The invention should however not be limited to the embodiment disclosed in the description.
The present invention is explained with example of manifold for a vehicle heat exchanger, wherein the manifold includes a header and a cover that are brazed along sidewalls thereof to define an enclosure to receive and hold a first heat exchange fluid therein. The sidewalls of the header are spaced to receive the sidewalls of the cover there-between. Further, each of the sidewalls of the header include section of reduced dimension to facilitate crimping between the header and the cover, particularly crimping of the sidewalls of the header over the sidewalls of the cover. More specifically, each sidewall of the header has a first section with a first thickness "t" and a second section with a second thickness "T", wherein the first thickness "t" is smaller than the second thickness "T" to facilitate crimping of the sidewalls of the header over the sidewalls of the cover. With such configuration of the sidewalls of the header, a step is formed at the interface of the first section and the second section of each of the respective sidewalls of the header. The steps so formed are disposed within the inside volume of the manifold and support the corresponding sidewalls of the cover to firmly hold and position the cover with respect to the header and prevent misalignment of the cover and the header. With such configuration, the problems caused by brazing defects arising due to insufficient contact between the header and the cover and misalignment between header and cover, particularly problems such as mechanical failure of the manifold and leakage of the first heat exchange fluid from the manifold are prevented. Further, with such configuration, free spaces at the brazing joint between the cover and the header are avoided, thereby preventing intrusion of moisture at the brazing joint between the cover and the header. Accordingly, the brazing joint between the cover and the header exhibits improved corrosion resistance as compared to conventional manifold. The sidewalls of the cover resting over the respective steps prevent over insertion of heat exchange tubes in the manifold. However, the manifold of the present invention is not limited to use in vehicle heat exchangers only and the same can be used in any heat exchanger used in vehicular and non-vehicular environment.
In case of a conventional manifold 10 as illustrated in FIG. 1, sidewalls 1a and 1b of a header 1 are spaced to receive the respective sidewalls 2a and 2b of a cover 2. The header 1 is crimped to the cover 2 to position the cover with respect to the header for sufficient contact between the sidewalls 2a and 2b of the cover 2 and the sidewalls 1a and 1b of the header 1 and efficient brazing there-between. However, such configuration fails to firmly hold and position the cover 2 with respect to the header 1 resulting in misalignment, particularly relative angular movement between the header 1 and the cover 2 during the crimping between the header 1 and the cover 2. Any misalignment of the header 1 with respect to the cover 2 before or during brazing may cause brazing defects that in turn lead to mechanical failure of the manifold 10 or leakage of the first heat exchange fluid from the manifold 10.
A manifold for a heat exchanger is disclosed in accordance with an embodiment of the present invention that obviates the drawbacks associated with the conventional manifold 10. FIG. 2a illustrates a schematic representation of a manifold 100 in accordance with an embodiment of the present invention formed by brazing a header 110 and a cover 120. FIG. 2b illustrates a schematic representation of the cover 120 of the manifold 100. FIG. 2c illustrates a schematic representation of the header 110 of the manifold 100.
Again referring to FIG. 2c , the header 110 includes a bottom wall 112 and two sidewalls 114 and 116, referred to as a first sidewall 114 and a second sidewall 116 of the header 110. Each sidewall 114, 116 of the two sidewalls 114 and 116 has a first section 114a, 116a with a first thickness "t" and a second section 114b, 116b with a second thickness "T", wherein the first thickness "t" is smaller than the second thickness "T". More specifically, each of the sidewalls 114 and 116 of the header 110 include section of reduced dimension to facilitate crimping between the header 110 and the cover 120, particularly crimping of the sidewalls 114 and 116 of the header 110 over the cover walls of 122 and 124 of the cover 120. Due to difference in thickness between the first section 114a, 116a and the second section 114b, 116b, steps 118a and 118b formed at interface of the first section 114a, 116a and the second section 114b, 116b of the respective side wall 114,116. The steps 118 and 118b are formed on inner side of the sidewalls 114 and 116 of the header 110 and as such support the cover-walls of 122 and 124 of the cover 120, when the cover 120 and the header 110 are assembled to each other. With such configuration of the header 110, preparing of comparatively thinner sections, particularly the first sections 114a and 116a of the sidewalls 114 and 116 of the header 110 for facilitating crimping between the header 110 and the cover 120 and forming support, i.e. forming the steps 118a and 118b for supporting the cover walls 122 and 124 of the cover 120 are created simultaneously in a single step, thereby easing the manufacturing and assembly process. The steps 118a and 118b extend along an entire length of the manifold 100. Alternatively, the steps 118a and 118b extend intermittently along the length of the manifold 100. However, the present invention is not limited to any particular configuration of the steps, particularly whether steps are continuous or intermittently formed, or whether the steps extend along the entire length of the manifold or not, until the steps stably support and position a pair of cover walls 122 and 124 of the cover 120 to prevent misalignment of the cover with respect to the header. The steps 118a and 118b are disposed within the inside volume of the manifold 100. More specifically, the first sidewall 114 includes the first section 114a with first thickness "t" and the second section 114b with second thickness "T", wherein the first thickness "t" is smaller than the second thickness "T". The first section 114a of the first sidewall 114 of the header 110 includes a first straight portion 115a. Due to difference in thickness of the first section 114a and the second section 114b of the first sidewall 114, the step 118a is formed at interface of the first section 114a and the second section 114b of the first sidewall 114. The step 118a is disposed within the inside volume of the manifold 100. Similarly, the second sidewall 116 includes the first section 116a with first thickness "t" and the second section 116b with second thickness "T", wherein the first thickness "t" is smaller than the second thickness "T". The first section 116a of the first sidewall 116 of the header 110 also includes a second straight portion 117a similar to the first straight portion 115a on the first section 114a of the first sidewall 114. Due to difference in thickness of the first section 116a and the second section 116b of the second sidewall 116, the step 118b is formed at interface of the first section 116a and the second section 116b of the second sidewall 116. The step 118b is disposed within the inside volume of the manifold 100. The bottom wall 112 of the header 110 includes a plurality of slots 112a to receive heat exchange tubes 130 therein. The steps 118a and 118b stably positions and supports the cover walls 122 and 124 and the chances of misalignment are prevented. Accordingly, the manifold of the present invention is convenient to manufacture as aligning, positioning of the cover 120 with respect to the header 110 and holding the cover 120 and the header 110 in proper position is achieved by the steps 118a and 118b formed on the header 110.
Again referring to FIG. 2b, the cover 120 includes the pair of cover walls 122 and 124, referred to as the first cover wall 122 and the second cover wall 124, corresponding to the first and the second sidewalls 114 and 116 of the header 110. The first cover wall 122 includes a first straight portion 122a corresponding to the first straight portion 115a formed on the header 110 and the second cover wall 124 includes a second straight portion 124a corresponding to the second straight portion 117a of the header 110. When the cover 120 and the header 110 are assembled and crimped, the inside walls of the first and the second straight portions 115a and 117a of the header 110 abut against the outside walls of the respective first and second straight portions 122a and 124a of the cover 120. Such configuration provide sufficient contact between the header 110 and the cover 120 for brazing between the cover 120 and the header 110. The first and the second cover walls 122 and 124 stably rests on the opposite steps 118a and 118b respectively. More specifically, the step 118a supports at least a portion of the thickness "Z" of the first cover wall 122. Similarly, the step 118b supports at least a portion of the thickness "Z" of the second cover wall 124. The first cover wall 122 and the second cover wall 124 can be of same or different thickness, accordingly, the steps 118a and 118b can be identical or dissimilar. In accordance with another embodiment, the step 118a and 118b supports entire thickness "Z" of the first cover wall 122 and the second cover wall 124 respectively. Also, the first and the second straight portions 122a and 124a of the first and second cover walls 122 and 124 abuts against the corresponding first and second straight portions 115a and 117a of the first and second sidewalls 114 and 116. Thereafter, the header 110 is crimped to the cover 120. With the first cover wall 122 and the second cover wall 124 stably resting on the respective opposite steps 118a and 118b, the chances of any relative movement between the header 110 and the cover 120 during crimping, due to crimping forces is prevented. With the straight portions 122a and 124a of the cover walls 122 and 124 abutting against straight portions 115a and 117a of the sidewalls 114 and 116 of the header 110, sufficient contact is achieved between the first and second sidewalls 114 and 116 of the header 110 and the corresponding first and second cover walls 122 and 124 of the cover 120 to form a robust brazing connection there-between. With the cover walls 122 and 124 firmly positioned and held with respect to the sidewalls 114 and 116 of the header 110, misalignment of the cover 120 with respect to the header 110 before or during the brazing is prevented. Accordingly, a robust brazing connection is formed between the header 110 and the cover 120, and brazing defects and problems, such as leakage from the manifold 100 and mechanical failure of the manifold 100, resulting from brazing defects are also prevented. Further, with such configuration, free spaces at the brazing joint between the cover 120 and the header 110 are avoided, thereby preventing intrusion of moisture at the brazing joint between the cover 120 and the header 110. Accordingly, the brazing joint between the cover 120 and the header 110 exhibits improved corrosion resistance as compared to conventional manifold.
In one embodiment of the present invention, the steps 118a and 118b supports at least a portion of the base of the cover walls 122 and 124 and the remaining portion of the base of the cover walls 122 and 124 overhang and extend beyond the respective step 118a and 118b towards an interior of the manifold 100. Once, the header 110a and the cover 120 are brazed together, the overhanging portion of the cover walls 122 and 124 prevents insertion of a section of the respective heat exchanger tube 130 beyond a pre-determined length inside the manifold 100. Such configuration of the manifold 100, achieves uniform distribution of first heat exchange fluid from the inlet manifold to the heat exchange tubes 130 and uniform collection of heat exchange fluid from the heat exchange tubes 130 into the outlet manifold. Accordingly, the efficiency and performance of the heat exchanger is enhanced.
In accordance with another embodiment of the present invention, the cover walls 122 and 124 of the cover 120 includes protrusion 126 protruding inwardly towards the interior of the manifold 100 to prevent insertion of a section of the respective heat exchanger tube 130 beyond a pre-determined length inside the manifold 100. FIG. 3a illustrates a schematic representation of the manifold 100 in accordance with another embodiment of the present invention formed by brazing the cover 120 and header 110, wherein each of the cover walls 122 and 124 of the cover 120 includes protrusion 126 protruding inwardly towards the interior of the manifold 100. More specifically, each of the cover walls 122 and 124 of the cover 120 includes protrusion on inner side thereof extending opposite to the first sections 114a and 116a of the respective sidewalls 114 and 116 of the header 110 when the header 110 and the cover 120 are assembled together and brazed to each other. FIG. 3b illustrates a schematic representation of the cover 120 of the manifold 100, wherein the cover walls 122 and 124 are formed with protrusions. FIG. 3c illustrates a schematic representation of the header 110 of the manifold 100.
In still another embodiment, at least one of the overhang of the cover wall resting on one of the corresponding step and the protrusion 126 protruding from the other cover wall and protruding inwardly towards the interior of the manifold 100 prevent insertion of a section of the respective heat exchanger tube 130 beyond a pre-determined length inside the manifold. More specifically, the over insertion of the heat exchange tube 130 inside the manifold 100 is prevented by the protrusion protruding from one of the cover wall on one side and the overhang of the other cover wall resting on the corresponding step on the other side.
Also is disclosed a heat exchanger 200 in accordance with an embodiment of the present invention. FIG.4 illustrates the heat exchanger 200. The heat exchanger 200 includes at least one manifold 100 in fluid communication with a plurality of heat exchange tubes 130, wherein the manifold 100 is as disclosed above.

Claims

A manifold (100) for a heat exchanger (200), the manifold (100) comprising:
• a header (110) comprising:
∘ a bottom wall (112);

∘ two sidewalls (114, 116), wherein each side wall (114, 116) has a first section (114a, 116a) with a first thickness "t" and a second section (114b, 116b) with a second thickness "T", wherein the first thickness "t" is smaller than the second thickness "T", wherein steps (118a, 118b) are formed at interface of the first section (114a, 116a) and the second section (114b, 116b) of the respective side wall (114, 116) and are disposed within the inside volume of the manifold (100);

• a cover (120) comprising cover walls (122, 124) corresponding to the sidewalls (114, 116) of the header (110) and adapted to rest on the opposite respective steps (118a, 118b).
The manifold (100) as claimed in the previous claim, wherein at least one of the steps (118a, 118b) extends along an entire length of the manifold (100).
The manifold (100) as claimed in any of the preceding claims, wherein the first section (114a, 116a) of the side wall (114, 116) comprises a corresponding straight portion (115a, 117a) abutting against a straight portion (122a, 124a) of the respective cover wall (122, 124).
The manifold (100) as claimed in any of the preceding claims, wherein the step (118a, 118b) is adapted to support at least a portion of the thickness "Z" of the respective cover wall (122, 124).
The manifold (100) as claimed in any of the preceding claims, wherein the step (118a, 118b) is adapted to support entire thickness "Z" of the respective cover wall (122, 124).
The manifold (100) as claimed in any of the preceding claims, wherein the bottom wall (112) of the header (110) comprises a plurality of slots (112a) adapted to receive heat exchange tubes (130) therein, the cover walls (122, 124) supported on the respective steps (118a) and (118b) are adapted to prevent insertion of a section of the respective heat exchanger tube (130) beyond a pre-determined length in the manifold.
The manifold (100) as claimed in any of the preceding claims, wherein at least a portion of at least one of the cover wall (122, 124) supported on the respective step (118a, 118b) overhangs and extends beyond the respective step (118a, 118b) towards an interior of the manifold (100).
The manifold (100) as claimed in any of the preceding claims, wherein at least one of the cover wall (122, 124) comprises protrusion (126) on inner side thereof, extending opposite to the respective first section (114a, 116a) of the side wall (114, 116) of the header (110) and towards an interior of the manifold (100).
A heat exchanger (200) comprising at least one manifold in fluid communication with a plurality of heat exchange tubes (130), wherein the manifold (100) is in accordance with any of the preceding claims.