FR3053450A1 - MECHANICAL HEAT EXCHANGER AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

The present invention relates to a heat exchanger (1) mechanical comprising tubes (3) parallel to each other and arranged in a row and a plurality of fins (4) superimposed having orifices (40) through which the tubes ( 3), at least two collector plates (5) respectively comprising holes in which the ends of the tubes (3) are introduced, a collecting plate (5) being arranged at each end of the tubes (3), the superposition of fins ( 4) being in a state of elastic deformation, said superimposition of vanes (4) being held in an unstable shape by the collecting plates (5) and the tubes (3) so that if said collecting plates (5) are removed, the superposition of fins (4) returns to a stable shape. The present invention also relates to a method of manufacturing said mechanical heat exchanger (1).

Description

© Publication number: 3,053,450 (to be used only for reproduction orders) (© National registration number: 16 56125 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © IntCI ⁸

F28 F1 / 24 (2017.01), F28 F 13/00

A1 PATENT APPLICATION

©) Date of filing: 29.06.16. © Applicant (s): VALEO THERMAL SYSTEMS (© Priority: Simplified joint stock company - FR. @ Inventor (s): MARCHADIER XAVIER, AZZOUZ KAMEL, DE VAULX CEDRIC, ETIENNE ERWAN, (43) Date of public availability of the BOISSELLE PATRICK and MONNET VERONIQUE. request: 05.01.18 Bulletin 18/01. (© List of documents cited in the report of preliminary research: Refer to end of present booklet (© References to other national documents @ Holder (s): VALEO THERMAL SYSTEMS related: Joint stock company. ©) Extension request (s): © Agent (s): VALEO THERMAL SYSTEMS.

MECHANICAL HEAT EXCHANGER AND MANUFACTURING METHOD THEREOF.

FR 3 053 450 - A1) 3 /) The present invention relates to a mechanical heat exchanger (1) comprising tubes (3) parallel to each other and arranged in a row and a plurality of superposed fins (4) comprising orifices (40) through which the tubes (3) pass, at least two collecting plates (5) respectively comprising holes into which the ends of the tubes (3) are introduced, a collecting plate (5) being arranged at each end of the tubes (3), the superposition of fins (4) being in a state of elastic deformation, said superposition of fins (4) being maintained in an unstable form by the collector plates (5) and the tubes (3) so that if said collector plates (5) are removed, the superposition of fins (4) regains a stable shape.

The present invention also relates to a method of manufacturing said mechanical heat exchanger (1).

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Mechanical heat exchanger and associated manufacturing method

The invention relates to the field of heat exchangers and more specifically mechanical heat exchangers and their manufacturing process.

Mechanical heat exchangers generally comprise parallel tubes with each other, forming a bundle of tubes, which are introduced into perforated fins. The tubes are for example widened by mechanical deformation in order to be held in the perforations of the fins. This mechanical deformation is for example achieved by inserting into the tube an olive with a diameter greater than that of the orifice of said tube in order to widen it.

The ends of the tube bundle are connected to manifolds formed in particular by a collecting plate provided with holes into which the ends of the tubes open. The collecting plate is covered with a water box so as to form the collector. The collectors allow the distribution or recovery of a first heat transfer fluid which passes inside the tubes. A second heat transfer fluid passes between the fins.

By mechanical heat exchanger is meant that the different elements forming the exchanger are mechanically fixed together, for example by crimping.

However, for these mechanical heat exchangers, the contact between the tubes and the fins may not be continuous but punctual. This decreases the thermal conductivity between the tubes and the fins and therefore decreases the performance of the heat exchanger.

One of the aims of the present invention is therefore to propose an improved mechanical heat exchanger, the performance of which is increased.

The present invention therefore relates to a mechanical heat exchanger comprising:

• tubes parallel to each other and arranged in a row and in which a first heat transfer fluid is able to flow, and • a plurality of superimposed fins through which a second heat transfer fluid is able to flow, said fins having orifices through which the tubes pass, • at least two collector plates respectively comprising holes into which the ends of the tubes are introduced, a collector plate being disposed at each end of the tubes, the superposition of fins being in a state of elastic deformation, said superposition of fins being maintained in an unstable form by the collector plates and the tubes so that if said collector plates are removed, the superposition of fins regains a stable form.

The fact that the superposition of fins is maintained in its unstable form applies mechanical stresses at the interface between the fins and the tubes. These constraints increase the contact pressure between the fins and the tubes, which improves the thermal conductivity between these elements and thus increases the performance of the mechanical heat exchanger.

According to one aspect of the invention, the superposition of fins is, in its stable form, curved in the plane of circulation of the flow of the second heat transfer fluid.

According to another aspect of the invention, the holes in the collector plates are aligned so that the tubes form a straight line and the fins are straight.

The present invention also relates to a method for manufacturing a mechanical heat exchanger, comprising:

• tubes parallel to each other and arranged in a row and in which a first heat transfer fluid is able to circulate, and • a plurality of superimposed fins through which a second heat transfer fluid is able to circulate, said fins having orifices through which the tubes pass, • at least two collector plates respectively comprising holes into which the ends of the tubes are introduced, a collector plate being disposed at each end of the tubes, said method comprising the following steps:

• assembly of the tubes and the fins with fixing of the said fins on the said tubes, • elastic deformation of the superposition of fins, • installation of the collector plates at the ends of the tubes.

According to one aspect of the method according to the invention, following the elastic deformation of the superposition of fins, the ends of the tubes are arranged so as to be placed opposite the holes of the collector plates.

According to another aspect of the method according to the invention, said manufacturing method comprises, between the step of assembling the tubes and the fins and the step of elastic deformation, an intermediate step of plastic deformation of the superposition of fins.

According to another aspect of the method according to the invention, the intermediate stage of plastic deformation of the superposition of fins is a bending in the plane of circulation of the flow of the second heat transfer fluid.

According to another aspect of the method according to the invention, the superposition of fins has a straight profile before the intermediate stage of plastic deformation and that said superposition of fins has a profile also straight after the elastic deformation step.

Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and nonlimiting example, and of the appended drawings among which:

Figure 1 shows a schematic representation of a mechanical heat exchanger in front view, Figure 2 shows a schematic representation of the mechanical heat exchanger of Figure 1 in top view, Figures 3a to 3c show representations schematic sectional view from above of a mechanical heat exchanger during different stages of its manufacturing process.

Identical elements in the different figures have the same references.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, and / or that the characteristics apply only to a single embodiment. Simple features of different embodiments can also be combined to provide other embodiments.

In the present description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter and second parameter or even first criterion and second criterion etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria similar but not identical. This indexing does not imply a priority of an element, parameter or criterion over another and one can easily interchange such names without departing from the scope of this description. This indexing does not imply an order in time for example to assess such or such criteria.

Figure 1 shows a mechanical heat exchanger 1. By mechanical heat exchanger 1 is meant that the various elements forming the exchanger are mechanically fixed together, for example by crimping. Said mechanical heat exchanger 1 comprises:

• tubes 3 parallel with each other and arranged in a row and in which a first heat transfer fluid is able to flow, and • a plurality of superposed fins 4 through which a second heat transfer fluid is able to flow.

These fins 4 move in parallel with each other and are superimposed. The fins 4 are arranged perpendicular to the plane of the row of tubes 3 and have orifices 40 (visible in FIGS. 3a to 3c) through which the tubes 3 pass.

Preferably, the fins 4 and the tubes 3 are made of metallic material, for example aluminum, in order to have good thermal conductivity and not to penalize the heat exchanges between the first and the second heat transfer fluid.

The mechanical heat exchanger 1 also comprises at least two manifold plates 5 respectively comprising holes 50 (visible in FIG. 2) into which the ends of the tubes are inserted. Said mechanical heat exchanger 1 comprises a manifold plate 5 at each end of tubes 3.

As shown in Figure 2, the holes 50 of the collector plates 5 can be aligned so that the tubes 3 form a straight row and the fins 4 are also straight. The fact that the fins 4 are straight makes it possible to limit the size of the heat exchanger 1.

Each collector plate 5 can be covered by a water box 6, the edges of which can be inserted into a groove 51 (visible in FIG. 2) which may include a seal, so as to form a collector 7. The collectors 7 comprise generally an inlet and / or outlet of the first heat transfer fluid and allow the distribution or evacuation of the first heat transfer fluid within the tubes

3.

In the mechanical heat exchanger 1, the superposition of fins 4 is in a state of elastic deformation. By elastic deformation is meant that the superposition of fins 4 has been deformed in order to pass from a stable form to an unstable form. The superposition of fins 4 is maintained in its unstable form by the collector plates 5 and the tubes 3. The collector plates 5 hold the tubes 3 which themselves maintain the superposition of fins 4 in its unstable form. If said collector plates 5 are removed, the superposition of fins 4 then regains a stable shape.

The fact that the superposition of fins 4 is kept in its unstable form applies mechanical stresses at the interface between the fins 4 and the tubes 3. These stresses increase the contact pressure between the fins 4 and the tubes 3 ce which allows an improvement in the thermal conductivity between these elements and thus increases the performance of the mechanical heat exchanger 1.

The superposition of fins 4 is, in its stable form, preferably curved in the plane of circulation of the flow of the second heat transfer fluid. H is nevertheless quite possible to imagine other directions or bending plan for the superposition of fins 4, said superposition of fins 4 would then be "straightened" by the collector plates 5 in order to apply stresses under its unstable shape.

The present invention also relates to a method for manufacturing a mechanical heat exchanger 1, comprising:

• tubes 3 parallel to each other and arranged in a row and in which a first heat transfer fluid is able to flow, and • a plurality of fins 4 through which a second heat transfer fluid is able to flow, said fins 4 comprising orifices 40 through which the tubes 3 pass, • a collecting plate 5 comprising holes 50 into which the ends of the tubes 3 are introduced, a collecting plate 5 being disposed at each end of the tubes 3, said method comprising the following steps:

• assembly of the tubes 3 and the fins 4 with fixing of the said fins 4 on the said tubes 3, • elastic deformation of the superposition of fins 4, in particular so that the ends of the tubes 3 are placed opposite the holes 50 of the collector plates 5 , • installation of the collector plates 5 at the ends of the tubes 3.

The attachment of the fins 4 to the tubes 3 can in particular be carried out by widening the tubes 3, for example by inserting an olive with a diameter greater than that of the orifice of the tube 3.

The elastic deformation can be carried out for example by means of one or more jacks.

As before, by elastic deformation, it is meant that the deformation is reversible. If the constraints maintaining the superposition of fins 4 in its unstable form are removed (for example by removing the collector plates 5), the superposition of fins 4 will return by itself in its stable form.

The manufacturing process can also include, between the step of assembling the tubes 3 and the fins 4 and the step of elastic deformation, an intermediate step of plastic deformation of the superposition of fins 4. By plastic deformation is meant that the deformation is not reversible and that following the plastic deformation the superposition of fins 4 remains in this form, which then becomes its stable form. The plastic deformation is thus a deformation of amplitude greater than the elasticity of the superposition of fins 4.

This plastic deformation can be carried out for example by means of one or more jacks.

It is then possible to assemble tubes 3 and fins 4, to fix said fins 4 on said tubes 3 and to form a superposition of fins 4 having a rectilinear profile, as illustrated in FIG. 3a.

The superposition of fins 4 is then plastically deformed, as illustrated in FIG. 3b, in order to obtain a superposition of fins 4 whose stable shape is curved, for example in the plane of circulation of the flow of the second heat-transfer fluid.

The superposition of fins 4 is then elastically deformed, as illustrated in FIG. 3c, in order to obtain a superposition of fins 4 whose unstable shape is for example of rectilinear profile, close to or identical to the superposition of fins 4 during of its assembly, that is to say also straight.

This example of the manufacturing process makes it possible in particular to keep a conventional mounting unit for assembling the tubes 3 and the fins 4 in order to form a superposition of fins 4 having a rectilinear profile. This also makes it possible to simply add units to the production chain in order to deform plastically, firstly, then elastically, secondly, the superposition of fins

4, which can limit the increase in production costs associated with these additional steps.

Thus, it is clear that the mechanical heat exchanger 1, due to the constraints applied on the superposition of fins 4, has improved performance.

In addition, due to its manufacturing process, the increase in production costs can be controlled.

Claims (8)

1. Mechanical heat exchanger (1) comprising: • tubes (3) parallel to each other and arranged in a row and in which a first heat transfer fluid is able to circulate, and • a plurality of superposed fins (4) through which a second heat transfer fluid is able to circulate , said fins (4) comprising orifices (40) through which the tubes (3) pass, • at least two collector plates (5) respectively comprising holes (50) into which the ends of the tubes (3) are introduced, a collector plate (5) being disposed at each end of the tubes (3), characterized in that the superposition of fins (4) is in a state of elastic deformation, said superposition of fins (4) being maintained in an unstable form by the collector plates (5) and the tubes (3) so that if said collector plates (5) are removed, the superposition of fins (4) regains a stable shape. 2. Heat exchanger (1) according to the preceding claim, characterized in that the superposition of fins (4) is, in its stable form, curved in the plane of circulation of the flow of the second heat transfer fluid. 3. Heat exchanger (1) according to one of the preceding claims, characterized in that the holes (50) of the collector plates (5) are aligned so that the tubes (3) form a rectilinear row and that the fins ( 4) are straight. 4. Method for manufacturing a mechanical heat exchanger (1), comprising: • tubes (3) parallel to each other and arranged in a row and in which a first heat transfer fluid is able to circulate, and • a plurality of superposed fins (4) through which a second heat transfer fluid is able to circulate , said fins (4) having orifices (40) through which the tubes (3) pass, • at least two collector plates (5) respectively comprising holes (50) into which the ends of the tubes (3) are introduced, a collector plate (5) being disposed at each end of the tubes (3), said method comprising the following steps: • assembly of the tubes (3) and the fins (4) with fixing of said fins (4) on said tubes (3), • elastic deformation of the superposition of fins (4), • installation of the collector plates (5) at the ends of the tubes (3). 5. Manufacturing method according to the preceding claim, characterized in that following the elastic deformation of the superposition of fins (4), the ends of the tubes (3) are arranged so as to be placed opposite the holes (50) header plates (5). 6. Manufacturing process according to one of claims 4 or 5, characterized in that it comprises, between the step of assembling the tubes (3) and the fins (4) and the step of elastic deformation, a intermediate stage of plastic deformation of the superposition of fins (4). 7. The manufacturing method according to the preceding claim, characterized in that the intermediate step of plastic deformation of the superposition of fins (4) is a bending in the circulation plane of the flow of the second heat transfer fluid. 8. Manufacturing method according to one of claims 6 or 7, characterized in that the superposition of fins (4) has a rectilinear profile before the intermediate stage of plastic deformation and that said superposition of fins (4) has 5 a profile also straight after the elastic deformation step. 1/2