EP0054796B1 - Modular cross-flow heat exchanger and method of manufacturing it - Google Patents

Description

The invention relates to cross flow heat exchangers.

These exchangers, essentially intended for heat exchanges between gas flows, in particular air flows, usually consist of an alternating stack of substantially square exchange plates, and corrugated spacer plates, of the same shape, the directions of the grooves constituting the undulations of these plates being alternately arranged in one direction and in the perpendicular direction, that is to say alternately in the two directions of the cross flows. The facing edges of two successive exchange plates which are parallel to the direction of the grooves of the spacer plate included between these two exchange plates must be connected to each other in a substantially sealed manner.

This sealed connection of the edges can be achieved by any suitable means, for example by welding or soldering as in the case of the US patent. 2,959,401. It can also be obtained by simply folding the edge of the underlying plate over the edge of the overlying plate, so that, over at least part of the width of this folded edge, the spacer plate between the two plates considered exchange is clamped between the underlying plate and this rim, and in addition this rim is pressed on the overlying plate by the following spacer plate which necessarily covers it. As a result, the folding of the two opposite parallel edges of each exchange plate must be completed before each new spacer plate and each exchange plate can be placed. It is therefore necessary to alternate the folding operations and the operations for placing the components of the stack, which complicates the manufacturing process. In addition, the sealing of the edges by simple covering is effective only if the metal used for the exchange plates has a sufficient thickness, for example, from 0.05 to 0.25 mm as in patent FR 2,365. 092.

For the sake of economy, and to improve the efficiency of the heat exchange, we are led to use, for the exchange plates as well as for the spacer plates, even thinner aluminum sheets, of a few parts millimeters thick only. In this case, the flexibility of these sheets does not allow a sufficient tightness to be achieved by simple folding, except if the width of the covering is increased sufficiently but in this case with a significant reduction in the exchange coefficient at the points of the doubling das walls, with, of course, an increase in the surface area of the sheet used which partially reduces the advantage of this reduction in thickness.

The object of the invention is to eliminate all the above drawbacks, that is to say to increase the efficiency of the exchange and reduce the amount of material used, by allowing the use of extra sheets. thin while achieving perfect sealing of the edges without significant overlap, and also to reduce the amount of labor required for manufacturing by allowing the various components to be stacked at once, then in a second stage sealing edges at various levels of the stack.

In the method according to the invention, each exchange plate is not square, but rectangular, and notched in the four angles, in a known manner, but asymmetrically so that after folding perpendicularly and in the same direction over a certain width of the two edges parallel to the short sides, the two lines of parallel folds thus obtained and the two other edges which are perpendicular to them are substantially inscribed in a square with symmetrical notches. Similarly, the corrugated spacer plates are not square but rectangular with a width equal to the distance between the edges of two notches increased by twice a certain offset, and a length equal to the width increased in turn by double this same offset, the assembly being mounted by simple alternating and crossed stacking of the various components, exchange plates and spacer plates, between four corner profiles which comprise, in the direction of the stacking, four dihedral angle entering between five projecting edges , the two extreme re-entering angles used for guiding the angles formed by each side of the square with the corresponding notch, and the two intermediate re-entering angles used for guiding and precisely positioning the corresponding angles of the various spacer plates.

After having achieved this stacking, the method provides for carrying out, preferably continuously, and successively at each level, a coating of glue on the internal faces of the flanges folded vertically and their folding as well as their pressing over the corresponding edge of the plate. overlying exchange, the width of these flanges having been determined for this purpose so that when folded inward it does not exceed the outer contours of the spacer plates positioned by the corner profiles.

In addition, the surfaces of said sections facing outwards from the stack are preferably striated asymmetrically and in a complementary manner so as to be able to fit together after one or more rotation of 90 ° in order to facilitate the grouping of several modules, and also a corner groove with re-entrant profile allowing the assembly of a cover profile, single or multiple.

• la fig. 1 représente à grande échelle et vue de dessus un angle de l'empilement des composants;
• la fig. 2 est une perspective éclatée illustrant le procédé de fabrication;
• la fig. 3 est une coupe verticale selon III-III de la fig. 1 au niveau du plateau inférieur;
• la fig. 4 est une vue partielle de dessus montrant l'assemblage modulaire de deux profilés d'angle avec in profilé de recouvrement double;
• la fig. 5 représente la section d'un profilé de recouvrement quadruple pour l'intersection de quatre modules.

Other features of the invention will appear in the description which follows of an embodiment and implementation taken as an example and shown in the appended drawing, in which:

• fig. 1 represents on a large scale and seen from above an angle of the stack of components;
• fig. 2 is an exploded perspective illustrating the manufacturing process;
• fig. 3 is a vertical section on III-III of FIG. 1 at the level of the lower plate;
• fig. 4 is a partial top view showing the modular assembly of two corner profiles with a double overlapping profile;
• fig. 5 shows the section of a quadruple cover profile for the intersection of four modules.

To manufacture an exchanger module according to the invention, an ultra-thin metal, generally aluminum, laminated to thicknesses between 0.02 and 0.04 mm, in sheets or strip, is used. y cut rectangular sheets whose long sides correspond to the outline 1 in figs. 1 and 2, and the short sides of which correspond to the contour 2a shown in phantom in FIG. 1 There is also an asymmetrical notching in each corner according to contours 3 and 4, this cutting being greatly facilitated by the thinness of the metal. In addition, the end flanges 2b of the length of the rectangle are folded perpendicularly upwards, for example upwards, around the lines of piliure 5, the initial edge 2a then coming in 2, and this so that the two lines of parallel folds. and opposite 5, and the two opposite edges 1 perpendicular to the preceding ones are inscribed in a substantially square contour, the side 3 and the remaining part on side 4 of the initial asymmetrical relief finally constituting a symmetrical relief. The exchange plate thus obtained is designated as a whole by 6.

With the same metal and in similar thicknesses, corrugated spacer plates 7 of rectangular shape are also produced with the successive grooves of the corrugations arranged parallel to the short sides. According to the invention, the width of each of the spacer plates 7, consequently measured in the direction of the grooves, is equal to the distance between two parallel edges 4 of the facing notches, increased by twice a certain offset d. In addition, the length of these spacer plates corresponds to its width, increased in turn by twice this same offset d. It follows that between the short side 8 of the spacer plate 7 and the fold line 5 adjacent, there remains a width 1 which is equal to the length of side 3 of the notch (or side 4 limited to the fold line 5) reduced by twice the distance d as shown in fig. 1. According to the invention, the width of the rim 2b, that is to say the distance between the fold line 5 and the initial edge 2a, is chosen to be less than or at most equal to the width 1 thus calculated of such so that when the flange is folded down, the glued part can be pressed without crushing the end 8 of the spacer plate 7 between the two exchange plates concerned by this folding, and moreover, without being hampered by the end 9 corresponding to the long side of the spacer plate immediately above since there is an additional clearance d between the two edges 8 and 9.

After having manufactured the two types of parts, exchange plate 6 and spacer plate 7, we proceed according to the invention to their simple stacking, without for the moment taking care of the connection. In this stack, each of the edges 1 of one of the plates 6 is inserted between the two vertical edges 2b starting from the fold lines 5 and is therefore in principle positioned in one direction but can slide in the direction of these fold lines. . In addition, the successive spacer plates 7 have more freedom and can both slide in both directions and also pivot in their plane. To ensure correct positioning of the various elements of the stack before their fixing, and also afterwards, in particular for the spacer plates, corner profiles are used, designated as a whole by 10, and which comprise on the side of the stack, a broken line profiling 11, 12, 13, 14, 15, 14, 13, 12, 11 comprising alternately four dihedral angles entering 12, 14, 14 and 12 comprised between five projecting edges 11, 13, 15, 13, 11. The assembly is intended to be placed as shown in FIG. 1, that is to say that the re-entrant angles 12 serve to center for each exchange plate the angles between the edge 4 of the notch and the fold line 5, or the angle between the edge 3 and the edge 1 , the latter in turn engaging in the rim 2b of the immediately lower plate. On the other hand, the two re-entrant angles 14 serve to center the alternating angles of the spacer plates 7 respectively in one direction and in the other direction.

The sections 10 can advantageously be made of extruded light alloy, and to avoid giving their walls excessive thicknesses, it is advantageous according to the invention to provide two deep grooves 16 which each open into the bottom of one of the angles 14 , the latter being in this virtual case, that is to say materialized only by the extension of the adjacent faces. These grooves are preferably extended until the edges 11 and 12 are aligned as shown in the figures.

To facilitate mutual nesting and precise centering of the various modules with respect to one another, when several juxtaposed modules are used, it is advantageous to provide the profiles 10 on their face facing outwards with suitable reliefs , for example sawtooth striations with alternately protruding edges 17 and intermediate recesses 18. While all of the entire profile 10 is so far symmetrical, it no longer taking into account these striations which are asymmetrically offset by half a step between the two sides of the 'right angle so that by juxtaposition of two identical sections without turning, one obtains as shown in fig. 4 a mutual interlocking centered of the two sections.

In addition, each of the corner profiles 10 has at its external angle a groove 19 with a re-entrant profile, preferably of substantially square section as shown in FIGS. 1 and 2 to allow the insertion by sliding of a cover profile 20 in the form of an angle iron internally comprising a rib 21 with a substantially carved bulge coming to fill the groove 19.

To ensure its mounting, each of the sections 10, cut to a length corresponding to the height desired for the exchanger module, is machined at its two ends so as to allow assembly with an end plate 22 terminating the module. There is shown in Figs. 1 and 4 by a mixed line P the mean plane of the ridges 17, 18, or if one prefers the primitive plane according to the teminology of the gear teeth. At each end of the profile section 10, as shown in FIG. 2, the outer walls 23 of the profile 10 are degreased with a strawberry over a height corresponding to the height of the plate 22, and over a depth corresponding at least to the thickness of the metal sheet constituting the plate 22 from the mean planes P , and in addition each of the two plates 22 is notched at each of its four angles as shown at 24 in FIG. 2, that is to say along the section of the external contour of the degreased end of the profile 10, with in addition a clearance 25 in the angle for the passage of the swollen rib 21 of the covering profile 20.

In addition, each of the ends of the sections 10 is also machined over a length corresponding to the height of the plates 22, in the form of a saw cut 26, visible only in FIG. 1, and which releases on this height the external walls 27 of the profile opposite with the edges 3 and 4 of the corner grudgeages.

This allows easy fixing of each of these sections 10 in the corresponding plate 22, by simple introduction into the corner cutout 24, then by folding horizontally under the plate 22 of the tab 27a formed by the end of each walls 27 separated from the profile by the longitudinal saw cuts 26. At the same time, the projections 17, at the limit of degreasing 28, abut on the upper edge of the ends of the flanges 29 of the plate 22 protruding inside the clearances 24. This fixing is therefore both geometrically rigorous and extremely economical.

To resume the manufacturing process as a whole, one can imagine that one starts from a plate 22 provided with its four sections 10 and that all the alternation of the components is stacked in one go, as explained above. Then, finishing is carried out at each level using a very simple tool comprising a carriage moving longitudinally along each fold line 5 and carrying a nozzle 30 for injecting glue, hot or cold, whose jet 31 is directed towards the inner face of the vertical edges 2b comprised between the fold lines 5 and the edges 2, and also a profiled presser 32 comprising a lower face 33, for example flat, and an upper face 34 of progressive shape , for example helical, to evolve from a substantially vertical section following the above-mentioned vertical rim 2b, to a substantially horizontal section pressing this rim 2b in the folded state on the surface 33 with interposition of the rest of the plate, below the fold line 5, and the unfolded edge 1b of the plate 6 immediately above. The upper part 34 is for example movable relative to the part 32 and pressed against the latter using elastic means not shown.

The finishing therefore consists simply in moving this carriage along a fold line 5, and starting again on each of the edges and each of the levels.

As we have seen previously, this bonding and this pressing present no difficulty thanks to the respective dimensions provided for this rim 2b and for the spacer plates 7, and also thanks to the precise positioning produced by the corner profiles 10. We have even given that at each level, such as that shown at the top of FIG. 2, there remains a width clearance d between the end of the grooves of the spacer plate 7 and the flange 2 folded down to allow the passage of the tools. Indeed, unlike the previous arrangement according to the aforementioned French patent, there is no penetration of the folded rim below the next spacer plate, and it is thanks to this that one can operate in just two operations, stacking, then finishing, instead of alternating stacking and folding operations.

Naturally, the stack ends at the upper part by another plate 22, not shown, similarly fixed by each of its angles to the upper ends of the profiles 10. However, in practice, it may be preferable, during the realization of the stack and when finishing the connections, not to use the final sections 10 but guide sections forming part of the tooling and which will then be replaced by the final sections. In this case, of course, the tool profiles have on their side opposite the stack the same broken line profile exposed above and which cor corresponds to that of the final profile. In particular, these tool profiles can be partially mobile to facilitate the operation of the gluing carriage. The subsequent positioning of the final sections 10 and the upper plate 22 then poses no difficulty.

Above all, the modules thus produced can be used in isolation. In this case, it is possible to mount in each of the angles a covering profile 20 of the type described above and insert, between the wings 35 of these profiles and the grooved faces 17 of the facing walls 23, a protective mesh which is automatically held by these wings.

It is also possible to produce larger assemblies by assembling together several modules by juxtaposition in one direction or in two directions, in this case replacing the covering profile 20 by that 20a shown in FIG. 4, or again by that 20b shown in FIG. 5. The section 20a also has two wings 35 in the extension for placing protective gratings of the two juxtaposed modules. On the contrary, the profile 20b is intended to be placed at the interior intersection of four juxtaposed modules where it is therefore not necessary to place protective mesh.

In addition to this justaposition of several modules in the two directions of the plane of the exchange plates, it is also possible to juxtapose or superimpose several modules in the direction perpendicular to the exchange plates, and this in an extremely simple manner since 'It suffices to use cover profiles, 20, 20a or 20b depending on the case, of a length multiple of that of a module to be able to ensure. both the meeting and the perfect alignment in superposition of the various modules, and in particular of the edges 29 of their plate 22. This thanks to the corner clearances 25 exposed above. The achievement of the seal between two adjacent flanges 29 thus precisely positioned poses no problem and can be resolved by any appropriate means, from simple adhesive tape, plastic or metal, to interlocking profiles or to the sleeves of interior interlocking.

Claims (10)

1. A countercurrent-flow exchanger module of the type consisting of alternating planar exchange plates and corrugated spacer plates disposed so that their corrugations alternately extend in two orthogonal directions, the edges of two succeeding exchange plates which extend in a direction parallel to the corrugations of the spacer plate therebetween being sealingly joined to each other at each level, characterized by the fact that each exchange plate (6) is rectangularly shaped and is provided in each corner thereof with an unsymmetrical notched portion (3, 4) in such a manner that after folding two end flanges (2b) along fold lines (5) parallel to the shorter sides the assembly defined by the two opposite fold lines (5) and the two edges (1) perpendicular there to is substantially inscribed in a square area and the remaining portion of the corner notched portions is symmetrical; and that the spacer plates (7) are rectangularly shaped, having a width greater than the distance between two notch edges (3 or 4) by twice an offsetting amount (d), and a length equal to the width plus twice said distance (d); the width of the flanges (2b) of the exchange plates (6) beyond the fold lines (5) being at most equal to the length of the side (3 or 4) of the remaining symmetrical notched portion minus twice said distance (d) whereby each of these flanges (2b) can be turned down over the edge (1 b) of the overlying exchange plate and pressed both against it and against the underlying plate without crushing therebetween the spacer plate (7) located between threse two exchange plates, while remaining spaced from the corrugation ends of the next upper spacer plate (7).

2. An exchanger module according to claim 1, characterized by the fact that it is provided in each corner thereof with a corner section (10) having on its surface facing towards the stack a shaped portion including four re-entrant dihedral angles (12, 14, 1.4, 12) between five projecting edges (11, 13, 15, 13, 11) positioned so that the outermost re-entrant angles (12) center the corners of the exchange plates on each side of the notched portion of the corresponding corner and that the two innermost re-entrant angles (14) each center the spacer plates (7) separately for each corrugation direction.

3. Exchanger module according to claim 2, characterized by the fact that said corner section is provided on its outwardly facing surfaces (23) with unsymmetrical striations (17, 18) adapted to fit in matching striations of a similar section through a mere displacement without upturning, and in it corner a recessed groove (19) adapted to cooperate with a raised rib (21) of a covering section (20).

4. An exchanger module according to claim 2 or 3, characterized by the fact that each coner section (10) is provided with deep longitudinally extending grooves (16) each terminating adjacent to a corresponding inner re-entrant angle (14) so as to define portions (27) which are connected to the section body (10) only by one side thereof.

5. A method for making an exhanger module according to any preceding claim, chracterized by the fact that, in a first step, the various components, exchange plates (6) and spacer plates (7) are stacked in alternate directions between corner sections (10) or tooling sections having similar shaped portions on the side facing towards the stack, and then, in a second step, finishing is carried out by applying adhesive onto the inner surfaces of the flanges (2b), turning down the latter over the corresponding edges (1 b) of the overlying exchange plate, and crushing the assembly (1b, 2b) against the surface of the underlying plate (6), this second step being preferably carried out by means of an evolutive tooling (32, 34) which moves linearly and operates successively at the various desired levels and on the four sides of the stack.

6. A method according to claim 5, characterized by the fact that each portion of the corner section (10) is fastened at each end thereof in the two end plates (22) by providing trimmed portions (28) in the section ends over the height extent of the plate, corner cut portions (24) in the corresponding plate to allow insertion of the trimmed portions, longitudinal sawing of the outer legs (27) of the section also over a length corresponding to the plate height, and by turning down these legs (27) in an orthogonal direction against the plate wall, each of the plates being also provided with a corner clearance (25) for accommodating the center rib (21) of the covering section (20, 20a or 20b).

7. A method according to claim 5 or 6, characterized by the fact that two modules disposed side by side and positioned by mutual fitting of the striations provided in the side surfaces of the corner sections (10) are joined together by placing a double covering section (20a) locking the two modules to each other, through longitudinal sliding.

8. A method according to any one of claims 5 to 7, characterized by the fact that the outer surfaces of a given module or assembly of several modules are protected by protecting grids which are kept in place by flanges (35) provided in the simple or double covering sections (20, 20a, respectively).

9. A method according to any one of claims 5 to 8, characterized by the fact that modules are disposed side by side in both directions of the exchange plates, and that the modules are connected at the edge common to four associated modules by means of a special covering section (20b) provided with ofur assembling ribs (21).

10. A method according to any one of claims 5 to 9, characterized by the fact that the modules or assemblies of modules arranged in groups in either or both directions of the plane of the exchange plates are stacked over each other in a direction orthogonal to the exchange plates and are grouped together using for the covering sections (20, 20a or 20b) multiples of the overall height of a module, a sealing connection between the edges (29) of the plates (22) being provided by any suitable means.

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