Heat exchanger tank

Abstract: A heat exchanger tank having an elongate channel-shaped casing (1) turned upside down, which defines an elongate bottom opening (11) and two end openings (13, 15). The tank is characterised in that the casing (1) is closed by an end plate (2) which is bent to a U-shape, having an elongate web portion (23) and two end walls (25, 27), wherein the web portion (23) closes the bottom opening (11) of the casing and the end walls (25, 27) close the end openings (13, 15) of the casing (1), and that the end plate (2) has a peripheral flange (32) which is connected, forming a seal, and extends parallel with the inner wall of the casing (1) at the said bottom openings (11) and end openings (13, 15). The invention also concerns a heat exchanger having a tank as above.

Description: The invention relates generally to a heat exchanger tank and more particularly to a heat exchanger tank having an elongate channel-shaped casing which is turned upside down and defines an elongate bottom opening and two end openings. The invention also relates to a heat exchanger incorporating such a heat exchanger tank. Heat exchangers are used in, for example, motor vehicles such as lorries and passenger cars in the form of a vehicle radiator which cools the engine block by means of circulating radiator liquid. A conventional radiator consists partly of two tanks and partly of a heat exchanger assembly located between them and connected to the tanks. One of the tanks functions as a collecting point for the heated liquid which comes from the engine block, whereas the other tank collects the cooled liquid from the heat exchanger assembly and leads it back out to the engine block. Heat exchangers also exist, of designs which have only one tank, in which case the liquid is led in and out of the same tank. The tank is then divided into two chambers. One known radiator has tanks which consist of a plastic casing and an end plate of an aluminium alloy, whereas the rest of the radiator, as for the end plate, is made of aluminium. The casing forms a trough turned upside down which is located over an end plate belonging to a heat exchanger assembly incorporated in the radiator, wherein packing for sealing is positioned between the plastic casing and the end plate. Said design has the great disadvantage that two very disparate materials are required to form the radiator tank. Designing the radiator tank and hence the whole radiator in two different materials has unfavourable implications for the reclaimability of the vehicle in which the radiator is installed. Since plastics and metals are reclaimed in quite disparate processes, the casing of the tank must be separated from the other portion of the radiator prior to recycling, and this results in additional expense making cost-effective reclaiming difficult. It has also been found that the plastic casing and the end plate are subjected to severe repeated stress at the point of connection between casing and end plate. The reason for this is that the plastic casing moves or expands as a result of changes in pressure inside the radiator tank. These movements tend to lead to cracking in the plastic casing or the end plate, resulting in risk of leakage. The disadvantage of designing the radiator tank in two different materials is eliminated by means of a conventional type of radiator, wherein both the heat exchanger assembly and the whole tank are made of brass. The tank is formed by a casing in the form of a trough turned upside down which is located above an end plate of the heat exchanger assembly. The edges of the trough are fitted into a V-shaped channel extending along the edge portions of the end plate. The connection of the trough to the end plate is further produced by means of soft soldering, through a solder material, preferably tin, filling the space between the edge portions of the casing and the walls of the channel. The said design of radiator tank has a number of other disadvantages, however. Owing to the location of the trough in the channel of the end plate, various fixtures are necessary to keep the trough in place during soldering. The soldering operation is also time-consuming, since a solder material applied from outside must always be applied to obtain the soldered joints. It is furthermore hardly favourable that the tank, like the rest of the radiator, should be designed in brass, since this results in heavy construction, which adversely affects the performance and fuel consumption of the vehicle, and also a structure with inadequate corrosion characteristics. A need therefore exists for a better solution than the prior art. In a known arrangement, disclosed in US-A-5366007, a heat exchanger tank is formed using inverted elongate channel-shaped casing which defines an elongate bottom opening and two end openings and has a substantially rectangular cross-section. In one arrangement, the walls which form the bottom opening are formed with an inwardly-directed slot or flange and an end plate is slid longitundinally into the casing to close it. In another embodiment the end plate has an inwardly-directed flange and the dimensions are such that the entire end plate is housed within the casing. In another known arrangement, disclosed in GB-A-2098313, a heat exchanger tank is has an inverted elongate channel-shaped casing which defines an elongate bottom opening and two end openings. The openings are closed by a bottom plate and two separate end plates. The bottom plate has a flange which extends to a trench portion for receiving the casing and the end plates have all round flanges for securing to the casing and to the bottom plate. One object of the invention is that the disadvantages of the previously known solutions described above are wholly or partially eliminated. Another purpose of the invention is that the heat exchanger tank should be designed so that connection of the parts incorporated in the heat exchanger becomes possible in a single soldering operation. A subsidiary purpose of the invention is that the heat exchanger tank can be joined together without need of external fixtures. A special aim of the invention is to produce a heat exchanger tank that is flexible in production. According to a first aspect of the present invention there is provided a heat exchanger tank having an inverted elongate channel-shaped casing which defines an elongate bottom opening and two end openings, and an end plate for closing the bottom opening and two end openings, said end plate being bent into a u-shape to define an elongate web portion, two end walls and a peripheral flange, extending in use along the bottom and end portions of the casing, said elongate web portion for closing said bottom opening, the peripheral flange extending on each side of said web portion to a trench for receiving said casing, and the peripheral flange being outwardly directed at said end walls, and further comprising a location means arranged at said end openings for locating the end plate at the casing prior to interconnection thereof. According to a second aspect of the present invention there is provided a heat exchanger having a heat exchanger assembly and at least one heat exchanger tank of the first aspect of the invention. Features of embodiments of the invention are set out in the dependent claims. A number of advantages over the prior art are achieved through the invention, in addition to the solution enabling the whole heat exchanger to be reclaimed in a simple way. The need for external fixtures for locating the tank beneath the brazing is eliminated owing to the design of the tank. Soldering the whole heat exchanger together in a single soldering operation is made possible thereby - which is an advantage financially, of course. Designing the casing as an upside-down channel with open ends creates greater flexibility in production, since the casing can be produced in longer lengths and then be cut to the desired length at a later stage. Lower storage costs are made possible thereby. The form of the casing also makes possible wider tolerances in length and height, since in both of these directions the casing lies with its inner surface in contact with the peripheral flange. The tolerances increase here from 0.2 mm to around 1 mm. Production of a casing only by bending a panel is furthermore advantageous financially - compared with deep drawing, for example. An embodiment of the invention will be described below with reference to the accompanying drawings, in which Fig 1 is an exploded perspective view showing a portion of the radiator tank as in the invention prior to assembly, and also a portion of a heat exchanger assembly incorporated in the radiator; Fig 2 is a perspective view of the radiator tank after assembly, together with a portion of the heat exchanger assembly incorporated in the radiator; Fig 3 is a sectional view showing a pipe clip or pipe socket for forming a liquid inlet to or a liquid outlet from the radiator tank, which liquid inlet is arranged on the radiator tank. In Fig 1 a portion of the radiator tank as in the invention is shown prior to assembly, together with a portion of the heat exchanger assembly incorporated in the radiator. Some portions belonging to the tank are cut away for clarity - the liquid inlet or outlet, for example. Some of these are shown in Fig 2 instead. The tank has an upside-down, channel-shaped, elongate casing 1 and an elongate end plate 2 which is connected to a heat exchanger assembly 3, of which only a portion can be seen in the figure. The tank and heat exchanger assembly 3 form, together with another tank (not shown) as in the invention, a vehicle radiator. The channel-shaped casing 1 has a web portion 5 and two side walls 7, 9, wherein the web portion 5 has a smooth transition to the side walls 7, 9. Owing to its channel-shape, the casing has a bottom opening 11 and two end openings 13, 15. It can be seen from Fig 2 that the casing 1 is also provided with a liquid inlet 17 formed by a pipe socket 19 and a U-shaped pipe clip 21, and a bracket 22 which is the means of coupling with other components situated adjacent to the radiator tank and which will be described in more detail below, as is also the connection of the respective liquid inlet 17 and bracket 22 to the casing 1. The end plate 2 is bent into a U-shape and has a flat elongate web portion in the form of a main section 23 which forms the base of the tank through closing of the bottom opening 11 of the casing 1, and two end walls in the form of end portions 25, 27, which form the end plates of the tank through closing of the end openings 13, 15, of the casing 1. The web portion or main section 23 and the end walls or end sections 25, 27, are designed in one piece in aluminium, and the end sections 25, 27, are directed substantially perpendicular to the main section 23. The main section 23 of the end plate 2 is designed with a number of openings 29 for receiving pipes 31 incorporated in the heat exchanger assembly 3. The pipes 31 are connected to the openings 29 of the end plate 2 by means of brazing. A peripheral flange 32 extends along the periphery of the end plate. The peripheral flange 32 is formed by two web portion or main section flanges 33, 35 extending along the longitudinal edges of the main section, two end wall or end section flanges 41, 43 extending along the periphery of the end sections, and four transition flanges 45 which are located in the transition between the respective main section flanges 33, 35 and the end section flanges 41, 43. Each main section flange 33, 35 extends outward substantially perpendicular to the main section 23. The outermost part of each flange 33, 35 is folded through approximately 180 degrees to form a V-shaped trench 37, 39 for receiving the side walls 7, 9 of the casing 1. The end section flanges 41, 43 extend outward from the respective end section substantially perpendicular to the respective plane of the end section. The transition flanges 45 extend outward in substantially the same plane as the main section flanges 33, 35. The flanges 33, 35 extend further in their transverse direction than the end section flanges 41, 43 in their respective transverse direction, so as to enable the V-shaped trench 37, 39 to be formed. The transition flanges 45 also have a substantially smaller extension in the transverse direction than both the main section flanges 33, 35 and the end section flanges 41, 43, to enable the bending that is necessary for the end sections 25, 27 to extend substantially perpendicular to the main section 23. A locating tongue 47 is further arranged on each end section flange 41, 43 to engage with the web portion 5 of the casing 1 and for locating the casing 1. The respective tongue 47 extends prior to mounting substantially perpendicularly outward from the respective flange and is situated in the outermost position on the flange viewed in its transverse direction, and in the middle of the flange viewed in its longitudinal direction. The tongue 47 is intended to be folded during assembly of the radiator tank approximately 90 degrees over the casing 1, so that it engages with the top of the casing. In Fig 2 the radiator tank is shown assembled and provided with the liquid inlet 17 and bracket 22. The liquid inlet has a hole (not shown) in one of the side walls 7, 9 of the casing 1. The pipe clip 21 also has a hole in one of its two substantially parallel end walls 51, 53 for receiving the pipe socket 19. The pipe socket 19 is provided at one of its ends with a peripheral flange 55 and is inserted into the pipe clip 21 from the rear or from inside, so that the flange 55 of the pipe socket 19 lies in contact with the inner surface of the pipe clip 21. In an outermost position on the respective end walls 51, 53 of the pipe clip 21, a means of fixing is arranged which comprises two projections 57, 59, 60, 64 (the projection 64 cannot be seen in the figure) which are situated in line with and at a distance from each other. Each projection 57, 59 of one of the end walls 51, 53 of the pipe clip 21 has an elongate slot 61, 62 extending in the transverse direction of the end wall, whereas each projection of the other end wall 53 has a locking flange 63, 68 (only one is shown) which extends inward towards the middle of the pipe clip 21. Each projection 57, 59 on one of the pipe-clip end walls forms, together with its locking slot 61, 62, a receiving element 66. The pipe clip 21 and the pipe socket 19 are passed over the casing 1 so that the pipe socket is arranged directly opposite the hole in one side wall 7, 9 of the casing. It can be seen from Fig 2 that one of the main section flanges 33 extending along the end plate has, at the place for the liquid inlet, parts of the folded-up portion of the flange cut away to form two locking tongues 65, 67 and for receiving the projection 57, 59 of one of the end walls 51. The locking tongues 65, 67 are of a size to fit into the slots 61, 62. On the main section flange 35 situated opposite also are parts cut away to receive the other end wall 53 of the pipe clip 21. This cannot be seen from the figure, however. The pipe clip 21 and the pipe socket 19 are located at the casing 1 through the locking tongues 65, 67 engaging with the slots 61, 62 and are clamped down against the lower portion of the respective projections 57, 59. On the opposite side of the pipe clip 21, the locking flanges 63 are folded around the outermost edge of the other main section flange 35 for locating the pipe clip 21 above the casing 1. The locking flanges 63 can, of course,-be replaced here by the solution shown on the opposite side, i.e. projections 57, 59 having slots 61, 62 which engage with locking tongues 65, 67. The bracket 22 is designed in one piece and, like the pipe clip, has a lower U-shaped portion for fitting together with and over the casing 1. The bracket 22 also has an upper bracket portion 69, in which there is a fixing hole (not shown). The bracket 22 also has two end walls 73, 75 (only one visible in the figure), each of which has two projections 77, 79, 80, 82 (only two visible in the figure). As for the pipe clip, the projection of one of the end walls is provided with slots 81, 83, whereas the projection of the other end wall is provided with locking flanges (not shown). Location of the bracket 22 over the casing 1 takes place in the same way as for the pipe clip 21 and will therefore not be explained further. All parts of the radiator tank are made of aluminium. Production of a radiator tank in accordance with the invention takes place as follows. The forming of the parts incorporated in the radiator tank is achieved by conventional bending, cutting, etc., and these initial production stages will therefore not be discussed further here. When the parts have been given the form described above, the casing 1 is positioned over the end plate 2, which has already been located in this position next to the heat exchanger assembly 3 incorporated in the complete vehicle radiator. The main section 23 of the end plate 2 has external dimensions matching those of the bottom opening 11 of the casing 1, and the end sections 25, 27 of the end plate 2 have external dimensions which match the two end openings 13, 15 of the casing 1 in order to obtain a close fit between the two parts. The inside surface of the casing 1 lies in the same plane as the peripheral flange 32 of the end plate 2, also to obtain a close fit between the parts. The outermost section of the respective side wall 7, 9 of the casing 1 thereby lies in contact with the main section flanges 33, 35 along its inside surface. The side walls 7, 9 are parallel with the respective main section flange 33, 35. The end sections of the casing 1 lie furthermore in contact with the end section flanges 41, 43 of the end plate 2 along the inside surface of the web portion 5 and side walls 7, 9 of the casing 1. Owing to the positioning of the casing 1 over the end plate 2, the bottom opening 11 of the casing 1 is closed by means of the main section 23 of the end plate 2 and their two end openings 13, 15 by means of the end sections 25, 27 of the end plate 2. The casing 1 is then located on the end plate 2 by folding the locking tongue 47 over the web portion 5 of the casing 1. Positioning of the liquid inlet 17 over the casing 1 is begun by passing the pipe socket 19 in through the hole in the pipe clip 21 from the rear or from inside, so that the flange 55 lies in contact with the inside surface of the pipe clip 21. The pipe clip 21 and pipe socket 19 are then positioned over the casing 1 through the respective locking tongue 65, 67, which in this stage extends substantially perpendicularly outward from the flange 33, being passed through the respective slots 61, 62 and clamped down against the respective projections 57, 59. The pipe clip 21 is then drawn down into the second end wall 53 so that it lies close against the outside surface of the casing 1 and is located through the locking flanges 63, 68 of the projection 60, 64 of the other end wall being folded around the lower edge of the opposite main section flange 35. The entire liquid inlet 17 is thereby located over the casing 1. Assembly of the bracket 22 to the casing 1 and end plate 2 takes place in the same way and is therefore not described further. It will be pointed out here that the liquid inlet 17 and the bracket 22 help to locate the casing 1 over the end plate 2. When all parts of the radiator tank have been assembled, the whole tank together with the other parts of the radiator is placed in an oven for brazing. The high temperature in the oven melts the outer layer on the casing 1, end plate 2, liquid inlet 17 and bracket 22 and also the other parts incorporated in the radiator, whereby this material acts as soldering material and joins the parts together. This is made possible by the outer layer having the composition of an aluminium alloy with a melting point lower than the aluminium in the other sections of the respective parts incorporated in the radiator. During brazing, the peripheral flange 32 of the end plate 2 is thus in contact with the inner wall of the casing 1 along the full length of the flange 32, and the peripheral flange 32 is therefore connected by brazing to the inner surface of the casing 1, forming a seal. The bottom opening 11 of the casing 1 is thereby closed sealingly by means of the main section 23 of the end plate 2, and the end openings 13, 15 of the casing 1 are closed sealingly by means of the end sections 25, 27 of the end plate 2. The liquid inlet 17 and the bracket 22 are connected to the casing 1 through the large area of contact between the pipe clip 21 and the bracket 22 and the casing 1, respectively, and connected to the end plate 2 through the engagement between the tongues 63, 67; 81, 83 and the projections 57, 59; 77, 79, respectively. The connection is made here also by brazing. With this brazing it is important that the surfaces to be brazed together should be very close to each other, not more than 0.2 mm apart, and that the solder surface should be at least a number of mm wide. These requirements are fulfilled by the radiator tank according to the invention, by means of the peripheral flange of the end plate and the self-location of the parts comprised in the tank. It will be realized that the present invention can be modified in several ways, within the context of the following claims. The casing 1 can, for example, be extruded instead of bent. The peripheral flange 32 can have, at the main section or web 23 of the end plate 2, a reverse extension to that of the embodiments described, i.e. the end section flanges 41, 43 can be directed inwards instead of outwards. The flange or tongue for fixing-in external components can equally well be replaced by a receiving means arranged to engage with a projection or a tongue located on the external component. It must also be emphasized that the invention is not confined to vehicle radiators, but can be utilized in other types of heat exchangers.

Claims: A heat exchanger tank having an inverted elongate channel-shaped casing (1) which defines an elongate bottom opening (11) and two end openings (13,15), and an end plate (2) for closing the bottom opening and two end openings, said end plate (2) being bent into a u-shape to define an elongate web portion (23), two end walls (25,27) and a peripheral flange, extending in use along the bottom and end portions of the casing, said elongate web portion (23) for closing said bottom opening, and the peripheral flange extending on each side of said web portion to a trench (37, 39) for receiving said casing, and the peripheral flange (32,41) being outwardly directed at said end walls, and further comprising a location means (47) arranged at said end openings (13,15) for locating the end plate (2) at the casing (1) prior to interconnection thereof. Heat exchanger tank according to claim 1, wherein the said location means (47) is a tongue provided on the peripheral flange (32) in an outermost position on each end wall (25, 27), for engaging the casing (1) by folding it over the casing. Heat exchanger tank according to claims 1-2, wherein the peripheral flange (32) extends along the entire periphery of the end plate (2). Heat exchanger tank according to claims 1, 2 and 3, wherein the peripheral flange comprises two web portion flanges (33, 35) and two end wall flanges (41, 43). Heat exchanger according to claim 4, wherein the web portion flanges (33, 35) are directed out from the casing (1). Heat exchanger tank according to any one of claims 1-5, wherein the peripheral flange (32) is directed substantially perpendicular to the general planes of the respective end plate portions (23, 25, 27). Heat exchanger tank according to any one of the preceding claims, wherein the peripheral flange (32) is at least partially bent over along at least a portion of the elongate web (23) to form the trench (37, 39) for receiving the casing. Heat exchanger tank according to any one of the preceding claims, further comprising coupling means (17; 22) to be connected to components located adjacent to the tank, the said coupling means (17; 22) surrounding the casing (1) with a form fit, and comprising fixing means (57, 59, 61, 62) for connection to the end plate. Heat exchanger tank according to claim 8, wherein the fixing means comprises at least one receiving element (66) adapted to engage a tongue or flange (65, 67) arranged on the web (23) of the end plate (2). Heat exchanger tank according to claim 9, wherein the receiving element (66) is a projection (57, 59) and a slot (61, 62). Heat exchanger tank according to any one of the preceding claims, wherein all parts incorporated in the tank are made of a solderable material. Heat exchanger tank according to any one of claims 1-10 preceding claims, wherein the connection between the end plate (2) and the casing (1) is achieved by brazing. Heat exchanger tank according to any one of claims 10-12, wherein the coupling means (17) is a liquid inlet or a liquid outlet. Heat exchanger having a heat exchanger assembly and at least one heat exchanger tank, wherein the heat exchanger tank is in accordance with any of claims 1-13.

Inventors: WIJKSTROM BJORN, WIJKSTROM, BJORN
Applicants: VALEO ENGINE COOLING AB, VALEO ENGINE COOLING AKTIEBOLAG
Application year: 1995
Main classification: F28F9
IPC codes: F28F9