EP1189009A1

EP1189009A1 - Stacked type heat exchanger

Info

Publication number: EP1189009A1
Application number: EP00308063A
Authority: EP
Inventors: Youichi Nakamura; Kimiaki Nakano
Original assignee: Toyo Radiator Co Ltd
Current assignee: Toyo Radiator Co Ltd
Priority date: 2000-09-15
Filing date: 2000-09-15
Publication date: 2002-03-20

Abstract

In a "stacked" type heat exchanger having a stack of elements (2) through the interior of which a first fluid flows and having a core support (5) arranged at the end of the stack in the stacked direction, the core support (5) includes slits (6) that extend from its edges up to the central portion, the slits (6) capable of slightly deforming when subjected to a thermal stress. It is thus possible to reduce the thermal stress which may be applied to both the core support (5) and the elements (2) when there arises a difference of thermal expansion therebetween.

Description

The present invention relates generally to a "stacked" type heat exchanger having a core consisting of a plurality elements and having a core support, and, more particularly, to a "stacked" type heat exchanger having a simple structure for absorbing or reducing a thermal stress that may be induced between the elements and the core support.
A "stacked" type heat exchanger comprises a core and a core support. The core is in the form of a stack of elements, each element consisting of a pair of dish-like plates that are placed one on top of the other, each plate having communication apertures formed at opposed ends thereof. The pair of plates are joined together at their peripheries in a liquidtight fashion to form an element, and a plurality of elements are stacked in a liquidtight fashion by way of the communication apertures. The core support is joined to one end of the stack of the elements in the stacked direction. The core support has at its opposed ends a pair of port openings that are joined to the communication apertures in the elements in a liquidtight fashion. By way of example, a high-temperature fluid flows through the interior of the elements , and a cooling water is passed through the exterior of the elements.
Due to the presence of difference of temperature between a first fluid flowing through the interior of each element and a second fluid passing through the external surface of the core support, there may arise a difference of thermal expansion between the elements and the core support. This may possibly result in an occurrence of cracks at the peripheries of the communication apertures that are junctions between the elements and the core support.
It would be desirable to be able to provide a "stacked" type heat exchanger having a less tendency to cause any cracks.
According to a first aspect of the present invention there is provided a "stacked" type heat exchanger comprising a core including a plurality of elements, each of the plurality of elements consisting of a pair of plates, each of the plates having communication apertures formed at opposed ends in the longitudinal direction, at least one of the plates being shaped into a dish, the plates being placed one on top of the other with their peripheries being jointed together in a liquidtight fashion, the plurality of elements being joined together in a liquidtight fashion by way of the communication apertures at the opposed ends , to thereby form the core; and a planar core support adapted to be joined to one end of the core, the core support having a pair of port openings that are in alignment with the communication apertures at the opposed ends; wherein the core support includes a plurality of slits that are disposed between the pair of port openings so as to intersect an imaginary line joining the pair of port openings , the plurality of slits being slightly deformable when a thermal stress is applied to regions between the pair of port openings.
Each of the plurality of elements and the core support may have elongated planar surfaces. The plurality of slits may include a first slit formed in the core support so as to extend from one edge in its transverse direction up to a position beyond the central portion in the transverse direction of the core support; and a second slit formed in the core support so as to extend from the other edge in its transverse direction up to a position beyond the central portion in the transverse direction of the core support.
The plurality of slits may include a pair of arcuate edge slits formed circumferentially around the port opening in the elongated core support, the pair of edge slits extending from adjacent edges of the core support toward each other; and an arcuate central slit formed concentrically with respect to the pair of edge slits, but with a slight radially inward offset relative to the pair of edge slits, the central slit having opposed ends that extend up to the vicinity of the adjacent edges .
The plurality of slits further may includes a pair of auxiliary edge slits extending from the adjacent edges concentrically with respect to the central slit, but positioned radially opposite to the pair of edge slits with respect to the central slit.
The present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:
FIG. 1 is a top plan view of a "stacked" type heat exchanger in accordance with a first embodiment of the present invention;
FIG. 2 is a schematic sectional view taken along a line II-II of FIG. 1 and viewed from the direction of the arrow;
FIG. 3 is a top plan view of a second embodiment of the "stacked" type heat exchanger; and
FIG. 4 is a top plan view of the major part of a third embodiment of the "stacked" type heat exchanger.
The present invention will now be described with reference to the accompanying drawings which illustrate preferred embodiments thereof in a non-limitative manner.
FIG. 1 is a top plan view of a "stacked" type heat exchanger in accordance with a first embodiment of the present invention, and FIG. 2 is a schematic sectional view taken along the line II-II of FIG. 1 and viewed from the direction of the arrow. FIG. 3 is a top plan view of a second embodiment of the present invention, and FIG. 4 is a top plan view of the major part of a third embodiment thereof.
The "stacked" type heat exchanger shown in FIGs. 1 and 2 comprises a multiplicity of elements 2, a multiplicity of annular spacers 7 interposed between the elements 2, and a core support 5 disposed at one end in the stacked direction. The element 2 consists of a pair of elongated plates each having communication apertures 1 formed at its opposed ends in the longitudinal direction, at least one of the plates being shaped into a dish, the pair of plates being placed one on top of the other, with their peripheral portions being joined together in a liquidtight fashion. The element 2 has a contour similar to that of the core support 5 of FIG. 1. The adjacent elements 2 are joined together in a liquidtight fashion at the communication apertures 1 by way of the annular spacers 7, with outer fins 9 being interposed between the external surfaces of the elements 2.
It is to be noted that no communication apertures are provided in the lower plate of the element 2 located at the lowermost end in the stacked direction. Alternatively, use may be made of the lower plate having the communication apertures that are closed by end plates.
At the uppermost end in the stacked direction, the core support 5 is placed by way of the spacers 7. As shown in FIG. 1, the core support 5 has at opposed ends in its longitudinal direction a pair of port openings 4 that are in alignment with the communication apertures 1. The core support 5 has a thickness which is typically greater than that of each place of the elements 2. The core support 5 is provided with first and second slits 6 and 6a that are positioned in proximity to the port openings 4 associated therewith. More specifically, the first slit 6 near the port opening 4 on one hand extends from one edge in the transverse direction to the vicinity of the other edge, and the second slit 6 near the port opening 4 on the other extends from the other edge in the transverse direction to the vicinity of the one edge. The slits 6 and 6a intersect an imaginary line A joining the centers of the pair of port openings 4 and are arranged symmetrically with respect to the center of each element.
As shown in FIG. 2, a boss 8 is joined to the opening edge of the port openings 4 of the core support 5, with a piping not shown being connected to the fore-end of the boss 8. Then, a high-temperature fluid flows through the boss 8 on one hand into each element 2 and communicates through the interior of each element 2 in the longitudinal direction, after which it exits the heat exchanger through the boss on the other not shown. Cooling water is passed through the external surfaces of each element 2, the outer fins 9 and the external surface of the core support 5 to thereby cool the high-temperature fluid lying within each element 2.
At that time , the thermal expansion of the elements 2 is greater than that of the core support 5, giving rise to a thermal stress therebetween. The thermal stress causes the slits 6 to deform toward the extension to thereby absorb the difference of thermal expansion between the elements 2 and the core support 5. Thus, as compared with the case of absence of the slits, the opening edges of the communication apertures 1 of each element 2 are subjected to a restricted thermal stress.
Referring then to FIG. 3 there is shown the second embodiment having, along the opening edge of the port opening 4 on one hand, a pair of edge slits 6b extending arcuately from the adjacent edges and a single central slit 6c positioned inside of the pair of edge slits 6b.
The central slit 6c is in the shape of an arc and has opposed ends that terminate short of the edges of the core support 5. The edge slits 6b are arranged radially outside of the slit 6c and each have an open end on one hand and a closed end on the other that extends up to the vicinity of the middle of slit 6c.
Referring then to FIG. 4 there is depicted the third embodiment further having, in addition to the features of the FIG. 3 embodiment, a pair of auxiliary edge slits 6d arranged radially inside of the central slit 6c and extending arcuately from the adjacent edges .
The FIG. 4 embodiment reduces the rigidity of the core support 5 itself to facilitate the slit deformation induced by the thermal stress.
The "stacked" type heat exchanger as defined in claim 1 enables the difference of thermal expansion between the elements 2 and the core support 5, attributable to the difference of temperature between the fluid passing through the interior of the elements 2 and the fluid passing through the external surface of the core support 5 , to easily be absorbed by the slits 6 formed in the core support 5. It is therefore possible to minimize the thermal stress applied to the communication apertures 1 in the elements 2 to thereby prevent any possible cracks, thus providing a "stacked" type heat exchanger having an extended service life.
According to the invention as recited in claim 2, the entire core support 5 can deform in a well-balanced manner when a thermal stress is applied thereto, by virtue of the first slit 6 formed in the core support 5 so as to extend from one edge in the transverse direction and by virtue of the second slit 6a formed in the core support 5 so as to extend from the other edge in the transverse direction. A highly reliable "stacked" type heat exchanger can thus be provided.
The "stacked" type heat exchanger as defined in claim 3 allows the core support 5 to be deformed easier, when subjected to a thermal stress, by the provision of the pair of arcuate edge slits 6b and the arcuate central slit 6c, to thereby ensure a well-balanced deformation of the core support 5.
According to the invention as recited in claim 4, an even easier thermal stress-induced deformation can be achieved.

Claims

A "stacked"type heat exchanger comprising:

a core including a plurality of elements (2), each of said plurality of elements (2) consisting of a pair of plates, each of said plates having communication apertures (1) formed at opposed ends in the longitudinal direction, at least one of said plates being shaped into a dish, said plates being placed one on top of the other with their peripheries being jointed together in a liquidtight fashion, said plurality of elements (2) being joined together in a liquidtight fashion by way of said communication apertures (1) at said opposed ends, to thereby form said core; and

a planar core support (5) adapted to be joined to one end of said core, said core support (5) having a pair of port openings (4) that are in alignment with said communication apertures (1) at said opposed ends;

characterised in that:

said core support (5) includes a plurality of slits (6) that are disposed between said pair of port openings (4) so as to intersect an imaginary line joining said pair of port openings (4), said plurality of slits (6) being slightly deformable when a thermal stress is applied to regions between said pair of port openings (4).
A "stacked" type heat exchanger according to claim 1, wherein

each of said plurality of elements and said core support have elongated planar surfaces, and wherein

said plurality of slits include:

a first slit formed in said core support so as to extend from one edge in its transverse direction up to a position beyond the central portion in the transverse direction of said core support; and

a second slit formed in said core support so as to extend from the other edge in its transverse direction up to a position beyond the central portion in the transverse direction of said core support.
A "stacked" type heat exchanger according to claim 1, wherein

said plurality of slits include:

a pair of arcuate edge slits formed circumferentially around said port opening in said elongated core support, saidpair of edge slits extending from adjacent edges of said core support toward each other; and

an arcuate central slit formed concentrically with respect to saidpair of edge slits, but with a slight radially inward offset relative to said pair of edge slits, said central slit having opposed ends that extend up to the vicinity of said adjacent edges.
A "stacked" type heat exchanger according to claim 3, wherein

said plurality of slits further includes:

a pair of auxiliary edge slits extending from said adjacent edges concentrically with respect to said central slit, but positioned radially opposite to said pair of edge slits with respect to said central slit.