ES2288403B1 - PROCEDURE FOR MANUFACTURING A TUBE FOR THE DRIVING OF A HEAT EXCHANGER FLUID, AND TUBE OBTAINED BY MEANS OF THIS PROCEDURE. - Google Patents

Abstract

Method of manufacturing a tube for the conduction of a fluid from a heat exchanger, and a tube obtained by means of said procedure. The tube (1) is of the type that has a substantially rectangular cross-section, being formed by two opposite walls of greater width and two rounded walls of smaller width. The procedure consists in performing the following steps: a) Starting from a metallic sheet (2), performing a plurality of corrugations (3) by means of a stamping process; b) Fold the sheet (2) by means of a stamping or forming process; and c) Proceed to weld the free edges (4) to close the tube (1), considering the required tolerances. A continuous procedure is obtained with a reduction in manufacturing costs.

Description

Manufacturing procedure of a tube for conduction of a fluid from a heat exchanger, and tube obtained by said procedure.

The present invention relates to a manufacturing procedure of a tube for the conduction of a fluid from a heat exchanger. The invention is also refers to the tube obtained by said procedure.

The invention is especially applied in Exhaust gas recirculation exchangers of an engine (EGRC).

Background of the invention

In some heat exchangers for the gas cooling, for example those used in recirculation of the exhaust gases towards the intake of an engine explosion (systems called "Exhaust Gas Recirculation" or EGR), the gases circulate through a bundle of parallel tubes housed in a housing, and during this circulation they are cooled by thermal exchange with a cooling fluid that is made circulate inside the housing, externally to the pipes passage of gases.

Section gas tubes are known rectangular suitable to be optimally fitted inside the casing of a rectangular section exchanger. Said rectangular section tubes are manufactured from a circular tube and can also present corrugations in order to improve the heat efficiency of the heat exchanger. Generally said corrugations extend along the tube length, but without reaching the radius of the tube, it is say the circular ends of it that have not been conformed

Currently, the only known method to be able to  machining the corrugations along the length of the tube in its entirety is through a hydroforming process.

The manufacturing process of this type of tubes is as follows:

First, it starts from a smooth tube of circular section, which has been obtained from a sheet bent and welded. Then the tube undergoes a process hydroforming that includes two stages: first proceed to form the tube that will go from having a circular section to a substantially rectangular section, and then the corrugations Finally, the cutting of the ends of the tube and deburring, if necessary.

Notwithstanding this manufacturing procedure The said tube has the following drawbacks:

- The cost of the manufacturing procedure is elevated due to the combination of various processes. By a part, the bent and welded tube used as primary material already it has an added value; on the other hand, the hydroforming process It has low rates since it is not a continuous process; plus it requires high investments since the machines and Tools are considerably expensive.

- Waste material from the procedure of manufacturing is high because during the hydroforming process it is it is necessary to have a circular section area at the ends of the tube, where the cylinders of the hydroforming machine will be placed to seal and inject the liquid at high pressure. By therefore, these circular section zones must be removed to Get the final shape of the tube.

Description of the invention

The purpose of the manufacturing process of a tube for the conduction of a fluid from an exchanger of heat of the present invention is to solve the drawbacks that present the procedures known in the art, providing a manufacturing process for the tubes with a lower cost

The manufacturing process of a tube for the conduction of a fluid from a heat exchanger, object of the present invention, said tube being of the type presenting a substantially rectangular cross section, formed by two opposite walls of greater width and two rounded walls of smaller width, is characterized by the fact that it consists of perform the following stages:

to)

Starting from a metal sheet, perform a plurality of corrugations through a process of stamping

b)

Fold the sheet through a stamping or forming process; Y

C)

Proceed to weld the free edges to close the tube, considering the tolerances required

In this way, a procedure of manufacturing that involves the combination in a production line of three different technologies: corrugation stamping, bending and welding.

Optionally, after stage c) proceed  to cut the end ends of the tube, if necessary.

The main advantages obtained By the method of the invention they are:

-

A reduction of production costs because the process is continuous, and consequently, the rates obtained are more higher than those obtained with the hydroforming process of tube.

-

A reduction of waste material because with this procedure is not necessary to have more material since only 1 mm per side is enough to carry out the welding points, and not as was the case with the hydroforming where at least 14 mm was needed.

-

The Production capacity obtained is higher.

-

A lower amount of investments since the machine and tools they are cheaper than those used for the tube made by hydroformed

-

He Required space in the industrial plant is smaller.

Preferably, the corrugations are stamped in those areas of the metal sheet corresponding to the opposite walls of greater width of the tube once mounted, reaching part of the smaller rounded walls width.

According to an embodiment of the invention, corrugations are defined by a plurality of grooves linear parallel to each other, running transversely wider walls according to a substantially diagonal direction to the axis of the tube.

Advantageously, the corrugations are stamped on along the metal sheet reaching the end ends, or Well avoiding the endpoints.

Preferably, the corrugations are distributed non-equidistant from each other, and not symmetrical with with respect to the bending line, in order to improve the loss of load.

In this case, the corrugations are distributed maintaining the same angle of inclination so that Once the metal sheet is folded, the corrugations of a wall They are positioned crosswise with respect to those on the wall opposite, defining each pair of associated corrugations a X-shaped projection.

Preferably, the folding of the sheet metal is made in half according to a central line longitudinal.

According to another aspect, the invention also refers to a tube for the conduction of a fluid from a heat exchanger, of the type obtained by the manufacturing procedure defined above.

Brief description of the drawings

In order to facilitate the description of what has been stated above, some drawings are attached in which, schematically and only by way of non-limiting example, a practical case of carrying out the manufacturing process of a pipe for the conduction of a fluid from a heat exchanger of the invention, in the four
them:

Figure 1 shows a metal sheet as Starting material;

Figure 2 shows the metal sheet with the corrugations performed according to stage a) of the procedure;

Figure 3 shows the folding process of the sheet according to step b) of the process; Y

Figure 4 shows the finished tube once stages c) and d) have been completed.

Description of a preferred embodiment

The procedure for manufacturing a tube 1 for the conduction of a fluid from a heat exchanger according to the invention it consists of the following steps:

First, it starts from a metal sheet 2 of approximately 60 mm (see figure 1).

Then, we proceed to perform a plurality of corrugations 3 by a stamping process, to along the metal sheet 2, avoiding reaching the central zone longitudinal 6 (see figure 2). Corrugations 3 can be stamped along the metallic sheet 2 in its total length, or avoiding the endpoints 5.

Next, we proceed to perform the folded of the sheet 2 in half according to a central line longitudinal, by means of a stamping or forming process. Figure 3 shows different phases of the folding of the sheet 2 in order to be able to close the tube 1.

Finally, the edges are welded free 4 to close tube 1, considering the tolerances required, and if necessary proceed to cut the ends end 5 of tube 1 to reach tolerances (see figure 4).

Although in the attached figures you can see a pattern of corrugations in the form of parallel oriented lines according to a diagonal direction, it is possible to apply any other type of patterns appropriate to the characteristics of the exchanger and the type of fluid to be cooled.

The process of the invention provides a  reduction of manufacturing costs since, on the one hand, no it is necessary to perform the previous operation of forming the sheet in a round tube, as in the procedures known in the prior art, and on the other hand, a procedure is obtained totally continuous

Claims (10)

1. Procedure for the manufacture of a tube (1) for the conduction of 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 greater width and two rounded walls of smaller width, characterized by the fact that it consists of performing the following stages:

to)

Starting from a metal sheet (2), perform a plurality of corrugations (3) through a process of stamping

b)

Fold the sheet (2) through a stamping or forming process; Y

C)

Proceed to weld the free edges (4) to close the tube (1), considering the tolerances required

2. Method according to claim 1, characterized in that after the end of step c) the end ends (5) of the tube (1) are cut. 3. Method according to claim 1 or 2, characterized in that the corrugations (3) are stamped on those areas of the metal sheet (2) corresponding to the opposite walls of greater width of the tube (1) once assembled , reaching part of the rounded walls of smaller width. Method according to claim 3, characterized in that the corrugations (3) are defined by a plurality of linear grooves parallel to each other, which cross said walls of greater width in a direction substantially diagonal to the axis of the tube. 5. Method according to any of claims 1 to 4, characterized in that the corrugations (3) are stamped along the metal sheet (2) reaching the end ends (5). Method according to any one of claims 1 to 4, characterized in that the corrugations (3) are stamped along the metal sheet (2) avoiding the end ends (5). Method according to any one of the preceding claims, characterized in that the corrugations (3) are distributed in a non-equidistant manner, and not symmetrical with respect to the bending line. Method according to claim 7, characterized in that the corrugations (3) are distributed maintaining the same angle of inclination so that once the metal sheet (2) is bent, the corrugations (3) of a wall are cross-positioned with respect to those of the opposite wall, each pair of associated corrugations defining a projection that is substantially X-shaped. Method according to any one of the preceding claims, characterized in that the folding of the metal sheet (2) is carried out in half according to a longitudinal central line. 10. Tube (1) for the conduction of a fluid of a heat exchanger, of the type obtained by the manufacturing process according to any of the claims 1 to 9.