MXPA00006045A - Fluid conveying tube as well as method and device for manufacturing the same - Google Patents

Abstract

A fluid conveying tube for a vehicle cooler comprises at least two longitudinal ducts, each comprising two opposite, longitudinal primary heat exchange surfaces. At least one primary surface in each duct of the tube has a projecting surface structure (8). In a method of manufacturing such a tube, starting from a blank, use is made of a device, which has a feeder for feeding the blank through the device and a surface forming station for forming the surface structure (8) on a portion (23) of the blank surface. Furthermore, the device comprises an edge forming station for forming two opposite edges of the blank into two upright edge portions (21, 22), which between themselves define an at least partly essentially flat web portion (23). In addition, the device comprises a duct forming station for making the edge portions (21, 22) abut against each other and against the web portion (23) with a view to defining said ducts.

Description

FLUID CONVEYOR TUBE AS WELL AS METHOD AND DEVICE TO MANUFACTURE THE SAME TICAL FIELD The present invention relates generally to vehicle coolers, and in particular to the design of fluid conveyor tubes in said coolers.

BACKGROUND OF THE INVENTION One type of vehicle cooler, which is described, for example, in EP-A1-0 590 945 and which is welded together, comprises a heat exchanger assembly comprising, on the one hand, a row of flat fluid conveyor tubes. , which are juxtaposed to be passed through a first fluid, for example, liquid flowing through a motor block and, on the other, surface enlarging means disposed between the tubes and adapted to be passed through a second fluid, for example, cooling air. Each tube has opposite large faces, to which surface enlarging means are applied and which form the primary heat exchanger sides of the tube. If for reasons of strength the large faces of the tubes can not have an optional width, the heat exchanger assembly is generally composed of several parallel rows of tubes, which are arranged successively in the flow direction of the second fluid through the exchanger assembly. of heat. Therefore, between each pair of rows there is an inactive zone where there is no heat exchange between the fluids. This inactive zone can comprise up to 10-15% of the total depth of the heat exchanger assembly. In order to increase the heat exchange capacity of the vehicle cooler, each tube is provided with several parallel internal channels, which are mutually separated by a thin dividing wall. In this way, the width of the tubes can be increased at the same time that the resistance is maintained, and the vehicle cooler can be formed without said inactive zone. Said "multi-channel tube" is, for example, known from EP-B-0 646 231. However, there is a constant need to improve the heat exchange capacity in vehicle coolers, especially since there is limited space for vehicle coolers in current vehicles, while increasing the need for cooling, particularly in trucks. An improved heat exchange capacity can be used to increase the cooling efficiency of a cooler having a certain size or reduce the size of a cooler that has a specific cooling efficiency.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the invention to provide a fluid transport tube and a vehicle cooler which by a specific size has a better heat exchange capacity than common constructions. Another object is to present a simple tique for manufacturing said fluid transporting tube at a relatively low cost and with a low degree of rejection. These and other objects, which will be apparent from the following description, have now been achieved by the method and a device for manufacture in accordance with appended claims 1 and 5, respectively, as well as a fluid conveyor tube and a fluid cooler. vehicle according to the appended claims 10 and 14, respectively. Preferred embodiments are defined in the dependent claims. The surface structure that forms inside the fluid transport tube serves to break the laminar limiting layer having an insulating effect and tending to form adjacent to the primary surfaces of the tube in the flow flowing through the tube. In this way, the surface structure contributes to further improve the heat exchange capacity of the tube, in particular at low fluid flow rates through the tube, without any substantial increase in the pressure drop in the fluid flowing to the tube. through the tube. Through the tique of inventive manufacturing, the tube can be formed in one piece starting with a preform of metal material in a simple and low cost manner. According to a particularly preferred embodiment of the inventive manufacturing technique, the preform is provided with the surface structure only after forming the two vertical edge portions along two opposite edges of the preform. This minimizes the risk of irregularities occurring at the outer edges of the preform during the formation of the surface structure on the surface of the preform, because the material of the preform has a tendency to twist when the structure is formed Of surface. Since the outer edges of the preform subsequently rest against the portion of tape to define the ducts, such irregularities could necessitate rejection of the tube due to runoff between the ducts.

BRIEF DESCRIPTION OF THE DRAWINGS Now the invention and its advantages will be described in more detail with reference to the accompanying schematic drawings, which by way of example show the preferred embodiments of the present invention. Figure 1 is an end view of a fluid transport tube according to the invention. Figures 2-6 are top plan views of a part of the fluid transport tubes according to different variants of the present invention. Figure 7 is a side view of a device of the invention for manufacturing a fluid transport tube. Figures 8a-8e are end views of a preform during the formation of the same to form a fluid transport tube, taking the respective end views at the positions ae in Figure 7. Figure 9 is a side view of a variant of the device in figure 7.

DESCRIPTION OF THE PREFERRED MODALITIES Figures 1-6 show preferred embodiments of a fluid transport tube according to the invention. The tube is conveniently made from a metal material, usually an aluminum material. As seen in Figure 1, the tube is flat and have two opposite large faces 1, 2, which are substantially planar. The large faces 1, 2 are connected through two opposite curved short sides 3, 4. When the tubes are mounted in a vehicle cooler, the surface enlarging means (not shown), for example bent sheets, are they support against the large faces 1, 2. The main heat exchange between the medium flowing through the tubes and the medium flowing through the surface enlarging means on the outer part of the tubes, takes place through of these large faces 1, 2. The tube internally defines two parallel ducts 5, 6, which are separated by a dividing wall 7 and extend in the longitudinal direction of the tube between their ends. The large faces 1, 2 form two opposite primary heat exchange surfaces V, 2 'in each duct 5, 6. As is evident from Figures 2-6, the primary surfaces V, 21 are provided with a surface structure in the form of a number of turbulence generating, projection 8 elements, which are called depressions. These depressions 8 may have an optional design and may be placed in an optional pattern on the primary surfaces 1 ', 2'. Figures 2-6 show, by way of example, different variants of the surface structure of the primary surfaces 1 ', 2' of the tube, the depressions 8 on the upper primary surface 1 'indicated by full lines and the depressions 8 on the lower primary surface 2 'are indicated by dotted lines. In all cases, the depressions 8 on the upper and lower primary surfaces 1 ', 2' are relatively misaligned, such that the tube has no opposing depressions 8 in cross section. These reduce the risk of blockage in the tube. In addition, the depressions 8 form laterally extending rows 9 on the respective primary surfaces 1 ', 2'. These rows 9 are arranged alternately on the upper and lower primary surfaces 1 ', 2', seen in longitudinal direction L of the tube. According to the variants in FIGS. 2 and 3, the depressions 8 are elongated and inclined relative to the longitudinal direction L of the tube. Within the respective rows 9, the depressions 8 are mutually parallel. Viewed longitudinally L, ie in the main flow direction of a fluid through the tube, depressions 8 are successively arranged on the upper and lower primary surfaces 1 ', 2'. According to the variant in FIG. 2, said depressions arranged in succession 8 are inclined at a given mutual angle, and according to the variant in FIG. 3 they are mutually parallel. According to the variants in Figures 4-6, the rows 9 of depressions 8 on the upper and lower primary surfaces 1 ', 2' are laterally offset, so that the successive depressions 8, seen in the longitudinal direction L, are placed on the upper or lower primary surface V, 2 '. In Figures 4 and 5, the depressions 8 are triangular and circular, respectively, in cross section parallel to the primary surfaces V, 2 '. In Figure 6, each depression 8 is elongated and arranged to extend in parallel with the longitudinal direction L of the tube. Next, an inventive device for manufacturing a tube according to Figs. 1-6 will be described together with Figs. 7-8. The device is designed to reshape a substantially flat preform or band 20 of a metal material, preferably an aluminum material, into a tubular section by successive bending operations. In this device, the band 20 passes between a number of pairs of driving arrows, which are adapted to feed the band 20 through the device and are provided with profiling tools. When introduced into the device, the edges or side faces of the band 20 are substantially parallel to the web feeding direction, which is indicated by arrows M in FIG. 7. The device has a first station 30, where the Profiling tools bend the lateral faces of the strip 20 perpendicularly substantially to the main plane of the strip. As seen in Figure 8a, after the first station 30 the band 20 has two vertical elongated edge portions 21, 22 and a portion of intermediate flat ribbon 23. In a subsequent station, second station 40, the portion of ribbon 23 of the band 20 is provided with depressions 8 in a defined pattern, for example, one of the patterns shown in Figures 2-6. Then, the band 20 passes between one or more combinations of a rotary support member 41 and a rotation arrow 42 having projections on its peripheral surface 43. At the same time it moves through the second station 40, the band 20 it is plastically deformed so that the cavities are formed on one of its sides and the corresponding projections on its opposite side, as shown in Figure 8b. It should be noted that the surface structure is greatly exaggerated in Figures 8a-8e for purposes of clarity. The device has a third station, subsequent 50 wherein the profiling tools successively bend the portion of tape 23 to form the two ducts 5, 6 (see Figures 8c-8e). In this embodiment, the vertical edge portions 21, 22 are arranged against each other to form the dividing wall 7 between the ducts 5, 6 (see Fig. 1). Furthermore, as shown in Figure 1, the outer edges of the edge portions 21, 22, i.e. the longitudinal outer edges of the band 20, are applied against the portion of tape 23. It should be understood that a high degree of of precision to ensure satisfactory fixing of these outer edges with the portion of tape 23 along the entire tube. After the third station 50, there is preferably a cutting station (not shown), wherein the formed tubular section is cut into desired lengths. However, it should be noted that, as an alternative to the previous preform in the form of a continuous, elongated strip, the preform may consist of substantially flat plates of a suitable dimension, which in the device of the invention are formed into tubular sections of a certain length. In this case, the cutting station can be omitted. According to an alternative embodiment, which is shown in Figure 9, the second station 40 'comprises one or more combinations of a splice element 41' and a die 42 '. The latter moves perpendicularly to the band 20 to make sure with it. Unlike the device in figure 7, the band 20 is introduced into the second station 40 ', where the stationary band 20 is plastically deformed to form slits on one of its sides and corresponding projections on its opposite side. On the other hand, the device of Figure 9 is identical to the device of Figure 7 and will therefore not be described in more detail. The tubular section discharged from the device in Figure 7 or 9, is subsequently joined to form a tube by autogenous welding in a furnace. It should be appreciated that the tubular section comprises at least partially filler material to form weld joints. In addition, a filler material is suitably applied by winding on both sides of the preform from which the tubular section is made. It is preferred that the tubular sections, together with the other components included in a vehicle cooler, be assembled to form an assembly, which is subsequently introduced into a autogenous welding furnace to form a vehicle cooler in a single autogenous welding operation. Thus, the tubes are formed at the same time as the rest of the vehicle cooler. It should be noted that the tube of the invention can be applied to all types of vehicle coolers having tubes arranged in parallel for cooling fluids, ie liquids or gases, such as liquid coolers, air-charged coolers, condensers and oil coolers.

Claims (6)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for manufacturing, starting from a preform of metal material, an elongated fluid transport tube, which is adapted to be mounted in a vehicle cooler and comprises at least two internal, elongated ducts (5,6), which comprises the steps of: forming a projection surface structure (8) on a portion (23) of the surface of the preform; forming, along two opposite edges of the preform, two vertical edge portions (21, 22), which together define at least a portion of partially essential flat tape (23), and form the portion of tape (23). ) so that the edge portions (21, 22) rest against each other and against the portion of tape (23) to define said ducts (5, 6).

2. A method according to claim 1, further characterized in that the step of forming the surface structure (8) is carried out after the step of forming the edge portions (21, 22), and the surface structure (8). ) is formed on said portion of tape (23).

3. A method according to claim 1 or 2, further characterized in that the surface structure, by plastic deformation of the preform, is formed as a plurality of projections (8) in a particular pattern on one of the sides of the preform

4. A method according to any of claims 1-3, further characterized in that the preform, in forming the surface structure, is arranged to extend through at least one splice (41, 42), comprising a fixing surface facing the preform and having a plurality of projections, and said projections are applied to the preform with a view to form said surface structure (8).

5. A device for manufacturing an elongated fluid transport tube, which is adapted to be mounted in a vehicle cooler and which comprises at least two internal, elongated ducts (5, 6), starting from a preform of metal material, said device comprising: a feeder for feeding the preform through the device, a surface forming a station (40) to form a projection surface structure (8) on a portion (23) of the surface of the preform, a station forming edge (30) to form two opposite edges of the preform into two vertical edge portions (21, 22), which therein define at least a portion of partially essential flat tape (23), and a forming station ducts (50) to make the edge portions (21, 22) supported against themselves and against the portion of tape (23) with a view to define said ducts (5, 6).

6. A device according to claim 5, further characterized in that the surface forming station (40), viewed in the feed direction of the preform through the device, is disposed downstream of the edge forming station (30) and is designed to form the surface structure (8) on said portion of tape (23). A device according to any of claims 5 or 6, further characterized in that the surface forming station (40) is designed to form, by plastic formation of the preform, a plurality of projections (8) in a pattern specific on one of the sides of the preform. 8. A device according to any of claims 5-7, further characterized in that the surface forming station (40) comprises at least one fixing surface facing the preform and has a plurality of projections. 9. A device according to claim 8, further characterized in that said fixing surface is formed on a peripheral surface (43) of a rotating roller (42) or on a die (42 ') that is perpendicularly applicable to the preform . 10.- A fluid conveyor tube for vehicle coolers, comprising at least two longitudinal ducts (5, 6) each comprising two opposite longitudinal primary heat exchange surfaces (1 ', 2'), characterized in that at least one primary surface (1, 2 ') in each duct (5, 6) has a surface structure generating turbulence, projection (8). 11. A fluid transport tube according to claim 10, further characterized in that it is made in a single piece of a preform of metal material. 12. A fluid transport tube according to claim 10 or 1 1, further characterized in that the surface structure has the form of a plurality of projections (8) distributed on said primary surface (1 ', 2'). 13. A fluid transport tube according to claim 12, further characterized in that the projections (8) in the longitudinal direction of each duct (5, 6) are arranged alternately on the opposite primary surfaces (1 ', 2') of such that each pipeline (5, 6) in cross section lacks opposing projections (8). 14. A vehicle cooler comprising a heat exchanger assembly and at least one tank connected to the heat exchanger assembly, characterized in that the heat exchanger assembly comprises fluid transporting tubes according to any of claims 10-13 and surface enlarging means arranged between the tubes. 15. A vehicle cooler according to claim 14, further characterized in that the components included in the cooler are joined by autogenous welding.