The present invention relates to a procedure for manufacture of a tube for conveyance of a fluid of a heat exchanger. The invention also relates to the tube obtained by such procedure.
The invention is particularly applicable in exchangers having recirculation of exhaust gases from an engine (EGRC).
In some heat exchangers for cooling gases, for example those employed in systems of recirculation of exhaust gases towards the admission of an explosion engine (systems denominated “Exhaust Gas Recirculation” or EGR), the gases circulate through a bank of parallel tubes housed within a casing, during such circulation being cooled by heat exchange with a cooling fluid circulated within the housing, externally to the tubes for the passage of the gases.
Tubes for gas of rectangular section are known suitable for fitting in an optimised manner within the housing of an exchanger of rectangular section. Such tubes of rectangular section are manufactured from a circular tube and may also present corrugations having the objective of improving thermal performance of the heat exchanger. Generally such corrugations extend along the length of the tube, however without reaching the radius of the tube, i.e. the unformed circular ends thereof.
Currently the sole known method to enable the machining of the corrugations along the length of the tube in its totality is by a hydroforming process.
The procedure for manufacture of this type of tube is as follows:
Initially, the starting material is a smooth tube of circular section obtained commencing from a bent and welded sheet. Subsequently, the tube is subjected to a hydroforming process including two stages: firstly forming of the tube is proceeded to it going from having a circular section to a substantially rectangular section, and subsequently the corrugations are realised. Finally, cutting off the ends of the tube and deburring is realised, if required.
Nevertheless this procedure for manufacture of such a tube presents the following disadvantages:
The objective of the procedure for manufacture of a tube for conveyance of a fluid of a heat exchanger of the present invention is to overcome the disadvantages presented by the procedures known in the art, providing a procedure for manufacture of the tubes having a lower cost.
The procedure for manufacture of a tube for conveyance of a fluid of a heat exchanger subject of the present invention, such tube being of the type presenting a substantially rectangular cross-section formed by two opposed walls of greater width and two rounded walls of lessor width, is characterised in that it consists of the realisation of the following stages:
In this manner a procedure for manufacture is achieved entailing the combination in one production line of three different technologies: corrugation embossing, bending and welding.
Optionally, following stage c), cutting off the extreme ends of the tube is proceeded to, if required.
The principal advantages obtained through the procedure of the present invention are:
Preferably, the corrugations are embossed in those zones of the metal sheet corresponding to the opposed walls of greater width of the tube once fabricated, attaining part of the rounded walls of lesser width.
According to one embodiment of the present invention, the corrugations are defined by a plurality of mutually parallel linear grooves transversely crossing said walls of greater width in a direction substantially diagonal to the axis of the tube.
Advantageously, such corrugations are embossed along the metal sheet, attaining the extreme ends or avoiding the extreme ends.
Preferably, such corrugations are distributed in a manner being mutually non-equidistant, and non-symmetrical with respect to the bend line, having the objective of improving the loss of load.
In such case the corrugations are distributed maintaining the same angle of inclination such that once the metal sheet has been bent, corrugations of one wall are positioned in a crossed manner with reference to those of the opposed wall, each pair of associated corrugations defining a projection substantially in the form of an X.
Preferably, the metal sheet is bent in half in accordance with a longitudinal central line.
According to another aspect the invention also relates to a tube for conveyance of a fluid of a heat exchanger of the type obtained employing the procedure for manufacture previously defined.
Having the objective of facilitating the description of that previously stated, some drawings are attached wherein, schematically and solely as a non-limitative example, there is represented a practical case of embodiment of the procedure for manufacture of a tube for conveyance of a fluid of a heat exchanger of the present invention, wherein:
The procedure for manufacture of a tube 1 for conveyance of a fluid of a heat exchanger according to the present invention consists of the following stages:
Initially, the starting material is a metal sheet 2 of approximately 60 mm (see
Then, realisation of a plurality of corrugations 3 is proceeded to employing an embossing process along the metal sheet 2, avoiding attaining the longitudinal central zone 6 (see
Subsequently, realisation of bending of sheet 2 in half is proceeded to in accordance with a longitudinal central line, employing a process of embossing or forming. In
Finally, welding free edges 4 to close tube 1 is proceeded to considering the tolerances required and, if necessary, cutting off extreme ends 5 of tube 1 to achieve the tolerances (see
Although in the attached figures a pattern of corrugations in the form of parallel lines orientated in a diagonal direction may be observed, it is possible to apply any other type of pattern appropriate for the characteristics of the exchanger and type of fluid to be cooled.
The procedure of the present invention provides a reduction in costs of manufacture because, on the one hand, it is unnecessary to realise the prior operation of forming the sheet into a round tube, as occurred in the procedures known in the state of the art and, on the other hand, a totally continuous procedure is achieved.
Number | Date | Country | Kind |
---|---|---|---|
P200600876 | Apr 2006 | ES | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2007/053309 | 4/4/2007 | WO | 00 | 8/12/2009 |