WO2010046257A1

WO2010046257A1 - Method of manufacturing a tube serving to convey a fluid of a heat exchanger, and tube obtained by means of said method

Info

Publication number: WO2010046257A1
Application number: PCT/EP2009/063254
Authority: WO
Inventors: Jesus Jimenez Palacios; Francisco Lopez Lazaro
Original assignee: Valeo Termico S.A.
Priority date: 2008-10-21
Filing date: 2009-10-12
Publication date: 2010-04-29
Also published as: KR20110079844A; EP2349599A1; ES2354896B1; KR20160063422A; ES2354896A1

Abstract

The invention relates to a method of manufacturing a tube (1). According to the invention, the method consists in carrying out the following steps: a) cutting a metal strip (2) from a spool to a length coinciding with the length (L) of the tube (1), the width of the spool coinciding with the width (A) of the development of the tube (1); b) forming by a stamping process the radii (3) corresponding to the rounded walls of small width; c) folding the strip (2) without closing its free edges (4); d) placing a metal filling material in the internal faces of the tube (1); e) placing disturbing means (5) inside the tube (1); f) closing the tube (1) by its free edges (4); and g) welding the tube (1). Application in particular to the automotive field.

Description

PROCESS FOR MANUFACTURING A TUBE FOR ROUTING UW

FLUID OF A HEAT EXCHANGER, AND TUBE OBTAINED USING THE SAME

The present invention relates to a method of manufacturing a tube for conveying a fluid of a heat exchanger. The invention also relates to the tube obtained by means of said method.

The invention finds particular application in the exhaust gas recirculation exchangers of a motor (EGRC) as well as in the thermoelectric generator (TEG) exchangers.

BACKGROUND OF THE INVENTION

In some heat exchangers used for cooling gases, for example those used in exhaust gas recirculation systems to the admission of an engine (called "Exhaust Gas Recirculation" or EGR), the gases circulate. in a bundle of parallel tubes housed in a carcass, and, during this circulation, are cooled by heat exchange with a cooling fluid circulated inside the carcass but outside the gas passage tubes .

Rectangular section gas tubes are known that can be optimally mounted in the casing of a rectangular section exchanger.

In order to improve the heat exchange, the tubes may comprise folds and / or disruptive gas means, such as fins, arranged inside the tube.

We know that the phenomenon of fouling depends largely of the distribution of the gas flow. The distribution of the gas flow in the heat exchanger depends on the distribution of the pressure drop of the gas through it. The paths of the gas stream experiencing a higher pressure drop have a lower flux value. This effect can, in an extreme case, cause stagnation and create almost zero circulation zones. Zones characterized by lower values of gas flow velocity are the seat of a significant increase in the deposition of the dirt layer. The influence of this effect leads to exchanger configurations where it is necessary to improve the distribution of the gas flow in the tubes.

JP2004263616 discloses a heat exchanger with a bundle of flat tubes of rectangular section. Each tube is made from two blades joined by their side edges and contains disruptive means attached to the inner surface of one of the blades. Said interfering means comprise a plurality of fins of pleated cross-section.

This configuration improves the distribution of the gas flow by preventing the soot from adhering to the inside of the tube.

JP2002327996 discloses a heat exchanger with a bundle of flat tubes of rectangular section. Each tube is also manufactured from two blades joined by their side edges and contains a plurality of protuberances intended to ensure correct positioning of disruptive means. Said interfering means comprise a series of fins arranged so as to improve the distribution of the gas flow.

JP2002295992 discloses a heat exchanger with a bundle of circular tubes. Each tube is provided with disturbing means placed inside once the tube has been welded, said disruptive means comprise fins arranged diametrically to improve the distribution of the gas flow.

These manufacturing processes however have the disadvantage that the disruptive means do not generally maintain good contact with the inside of the tube, which mechanical strength and thermal efficiency are thereby reduced.

DESCRIPTION OF THE IIWENTION

The method of manufacturing a tube for conveying a fluid of a heat exchanger of the present invention aims to overcome the disadvantages of the methods known in the art by providing a simple and less expensive method.

The method of manufacturing a tube for conveying a fluid of a heat exchanger object of the present invention, said tube being of the type having a substantially rectangular cross section, formed by two opposite walls of large width and two walls rounded small width, is characterized in that it consists in implementing the following steps: a) Cut a metal blade from a coil to a length coinciding with the length of the tube, the width of the coil coinciding with the width of tube development; b) forming by a process of stamping the rays corresponding to rounded walls of small width; c) Making the folding of the blade without closing its free edges; d) Place a metallic filling material in the internal faces of the tube; e) Place disturbing means inside the tube; f) Close the tube by its free edges; and g) proceed to weld the tube,

The manufacturing method of the present invention makes it possible to simply and efficiently produce a tube with a high thermal efficiency.

The free edges of the tube can be welded in the oven or by laser or TIG welding depending on the thickness of the material to be welded and the geometry of the connection.

According to one embodiment of the invention, the step g} of welding is carried out by baking the free edges of the tube, as well as disruptive means to the inner faces of the tube, along with the rest of the exchanger connections .

According to another embodiment of the invention, the welding step g} is carried out by laser or TIG welding of the free edges of the tube, and by welding in the oven of said interfering means to the internal faces of the tube, at the same time as the rest of the tubes. connections of the exchanger.

The main advantages offered by the method of the invention are: - A reduction of production costs because it is a continuous process thus allowing to obtain high rates.

- A simple baking process, the flatness of the tube allows for a more precise baking.

- Possibility of placing the metal filler material in the tube to perform the baking before placing the disruptive means, this only if the tube is manufactured according to the method of the invention, in thus ensuring low tolerances and better contact between the inner walls of the tube, the metallic filling material and the interfering means. It is also very important to baffle the interfering means to the tube during a final step of the process so as to guarantee the thermal efficiency and the fatigue resistance of the tube.

- Good geometry for bending the tube with a connecting flange. As rays have been formed in the outer surface of the tube, and therefore there are no discontinuities such as folded ends, the quality of the baking process is much better than that obtained with other geometries. .

Preferably, prior to step g) of welding in the oven, the final ends of the tubes are mounted on a support plate.

Preferably, the metallic filler material is a nickel blade. Said nickel blade is more particularly BNi2.

Preferably, the tube is made of stainless steel. Preferably, the step c) of folding the metal blade takes place by half along a central longitudinal line.

Optionally, prior to the folding step c), recessed depressions or protuberances are formed in the opposite walls of large width, at a sufficient distance from the spokes to avoid any problem of bending or deformation.

Optionally also, prior to the step c) of folding, forming internal reinforcing ribs to avoid any deformation.

In another aspect, the invention also relates to a tube for conveying a fluid of a heat exchanger, of the type obtained by means of the manufacturing method defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate the description of what has been explained above, drawings are enclosed in which is shown, in schematic form and only by way of non-limiting example, a practical case of realization of the method of manufacturing a tube. for conveying a fluid from a heat exchanger of the invention. In these drawings: FIG. 1 shows a metal blade as a starting material, already cut along the length of the tube; Figure 2 is a cross section of the metal blade showing the formed rays; Figure 3 is a cross section of the metal blade showing the process of folding said blade; Figure 4 is a cross section of the metal blade showing the process of placing disruptive means inside thereof, after the introduction of the metal filler material; and Figure 5 is a cross-section of the finished tube once closed and oven-welded.

DESCRIPTION OF A PREFERRED EMBODIMENT

The method of manufacturing a tube 1 for conveying a fluid of a heat exchanger according to the invention consists in implementing the following steps:

Firstly, a metal strip 2 is cut from a coil to a length coinciding with the length L of the tube 1, the width of the coil coinciding with the width A of the tube 1 development (see figure D •

The spokes 3 corresponding to the rounded walls of small width are then formed by a stamping process (see FIG.

Subsequently, the blade 2 is folded without closing its free edges 4. The folding of the blade 2 takes place by half along a central longitudinal line (see FIG. 3). Then, a metallic filler material (not shown) is placed in the internal faces of the tube 1 and then disordering means 5 are placed inside the tube 1 (see FIG.

Finally, the tube 1 is closed by its free edges 4, and the said free edges 4 of the tube 1 are then welded to the oven and, simultaneously, said disruptive means 5 to the internal faces of the tube 1 (see FIG.

5).

On the other hand, prior to welding in the oven, the final ends of the tubes 1 are mounted on a support plate. The welding of other tubes of the entire heat exchanger is also carried out during the baking of the tubes 1. The metallic filler material is a BNi2 nickel plate; and the tube is made of stainless steel.

The tube 1 may further comprise depressions or protrusions embossed in opposite walls of large width, at a sufficient distance from the spokes 3 to avoid any problem of bending or deformation. The tube

1 may also include internal reinforcing ribs to prevent any deformation.

Claims

1. A method of manufacturing a tube (1) for conveying a fluid from a heat exchanger, said tube (1) being of the type having a substantially rectangular cross section, formed by two opposite walls of large width and two rounded walls of small width, characterized in that it consists in implementing the following steps: a) Cut a metal blade (2) from a coil to a length coinciding with the length (L) of the tube (1) , the width of the coil coinciding with the width (A) of the development of the tube (1); b) forming by a process of stamping the spokes (3) corresponding to rounded walls of small width; c) Making the folding of the blade (2) without closing its free edges (4); d) placing a metallic filling material in the inner faces of the tube (1); e) Place disturbing means (5) inside the tube (1); f) Close the tube (1) by its free edges (4), and g) Proceed to the welding of the tube (1),

2, A method according to claim 1, characterized in that the step g) of welding is performed by baking the free edges (4) of the tube (1), as well as disruptive means (5) to the inner faces of the tube (1), at the same time as the rest of the exchanger connections.

3. Method according to claim 1, characterized in that the g) welding step is performed by laser welding or TIG of the free edges (4) of the tube (1) and by baking said disruptive means (5) to the inner faces of the tube (1), together with the rest of the exchanger connections.

4. Method according to claim 1, characterized in that, prior to step g) of welding in the oven is proceeded to the mounting of the ends of the tubes (1) on a support plate.

5. Method according to claim 1, characterized in that the metal filler material is a nickel blade.

6. Method according to claim 5, characterized in that said nickel plate is more particularly BNi2.

7. Method according to claim 1, characterized in that the tube (1) is made of stainless steel.

8. Method according to claim 1, characterized in that the step c) of folding of the metal blade (2) takes place by half along a central longitudinal line.

9. A method according to claim 1, characterized in that, prior to the step c) of folding, hollow or protruding stampings are formed in the opposite walls of large width, sufficient distance from the spokes (3) to avoid any problem of bending or deformation.

10. A method according to claim 1, characterized in that prior to the step c) of folding, forming internal reinforcing ribs for avoid any deformation.

11. Tube (1) for conveying a fluid of a heat exchanger, of the type obtained by means of the manufacturing method according to any one of claims 1 to 10.