EP0028951B1 - Heat exchanger comprising a bundle of tubes opening into collector panels mechanically associated with water vessels - Google Patents

Description

The present invention relates to heat exchangers comprising a bundle of tubes engaged in collecting plates which are designed to be covered by water boxes assembled in a removable manner, that is to say fixed on the periphery of each collecting plate with interposition of a deformable joint.

Up to now, in this type of heat exchangers, it is necessary to produce the water boxes in molded synthetic material so that they have, at their lower part, a thick and protruding heel or rim on which are crimped. legs or projections formed either by the collecting plate itself, or by an attached clamp.

However, it was not possible to use the same technique when using metal water boxes, because these boxes necessarily have a small wall thickness and, consequently, it is not possible to form, economically , a thick heel allowing effective crimping.

In an attempt to provide a solution to this problem, British patent 699,032 has described embodiments in which the peripheral edge of the water box is crimped onto a flexible joint by forming a hollow rib which is intended to increase the stiffness of the edge. .serti-This apparently satisfactory arrangement requires the use of complex tools to form the hollow rib inside which is placed the flexible seal.

The Applicant has itself described in FR-A-2270 471 exposing them. features of the preamble of claim 1 an embodiment in which the peripheral edge of the water box has a rounded conformation to increase its rigidity and, in this case, the edge of the collector plate is crimped on the raised end of the peripheral edge of the water box.

Difficulties have arisen in practical implementation since the devices for crimping the tabs of the collector plate inside the curved part of the peripheral edge of the water box often have the effect of deforming this peripheral edge and, consequently, of warp the part of the peripheral edge which normally rests on the flexible seal.

According to the invention, the heat exchanger comprising a bundle of tubes opening into collector plates delimiting, at their periphery, a groove externally bordered by a rising edge, a seal being arranged in the bottom of the groove for be clamped by the underside of a rim formed by a water box having a thin wall and maintained either by crimping parts extending the rising edge of the collector plate, or by an attached pliers is characterized in that a bar is interposed between the top of the rim of this water box and the crimping parts of the collector plate or the attached pliers.

• La figure 1 est une perspective partielle, en partie arrachée, d'un échangeur de chaleur faisant application de l'invention.
• La figure 2 est une perspective partielle analogue à la fig. 1 d'une variante.
• La figure 3 est une perspective d'un organe particulier utilisé pour la mise en oeuvre de l'invention.
• La figure 4 est une coupe partielle illustrant une variante de l'invention.
• La figure 5 est une coupe illustrant un développement de l'invention.
• La figure 6 est une coupe vue suivant la ligne VI-VI de la fig. 5.

Embodiments of the object of the invention are shown, by way of nonlimiting examples, in the accompanying drawing.

• Figure 1 is a partial perspective, partially broken away, of a heat exchanger applying the invention.
• FIG. 2 is a partial perspective similar to FIG. 1 of a variant.
• Figure 3 is a perspective of a particular member used for the implementation of the invention.
• Figure 4 is a partial section illustrating a variant of the invention.
• Figure 5 is a section illustrating a development of the invention.
• Figure 6 is a sectional view along line VI-VI of FIG. 5.

In the drawing, 1 denotes the circulation tubes of a heat exchanger, in particular of a cooling exchanger of the kind used in motor vehicles. These tubes are connected together in the usual way by dissipators 2 constituted, for example, by corrugated strips or by fins.

The ends of the tubes 1 are engaged in collector plates 3 which have, at their periphery, a groove 4 and an external rising edge 5. The collector plates 3 which the exchanger comprises are made of a metal or an alloy compatible with the metal or alloy of the tubes 1 and of the dissipators 2 and all of these parts are joined together by brazing or by another means.

According to the invention, a thin-walled water box 6 is used to cover the collectors 3 which is advantageously made of metal, in particular by stamping. Although this is not shown; the water box comprises in known manner pipes, bases and other conduits usual in the art.

In fig. 1, the water box has at its base a peripheral rim 7 of width corresponding to that of the groove 4 of the collector plate 3 and this rim is extended, in particular to stiffen it, by a rising edge 8.

• On dispose, tout d'abord, urr joint d'étanchéité déformable 9 dans le fond de la gorge 4, puis on pose la boîte à eau 6 sur le joint. Une opération suivante consiste à mettre en place, entre le bord montant 8 et la paroi périphérique de la boite à eau 6, une barrette 10 qui peut être fabriquée en différentes matières mais qui doit être, de préférence, rigide et peu ou pas déformable compte tenu des efforts qu'elle doit supporter. Des résines synthétiques du genre polyamide peuvent être utilisées pour constituer la barrette qui pourrait, d'ailleurs, être métallique.

To set up the water box 6 and seal it with the collecting plate, proceed as follows:

• First, there is a deformable seal urr 9 in the bottom of the groove 4, then the water box 6 is placed on the seal. A next operation consists in putting in place, between the rising edge 8 and the peripheral wall of the water box 6, a bar 10 which can be made of different materials but which must preferably be rigid and little or not deformable. given the efforts it must bear. Synthetic polyamide-type resins can be used to form the strip which could, moreover, be metallic.

It is advantageous, as illustrated in the drawing, for the bar 10 to form a bead 11 covered to the top of the rising edge 8 of the box.

A next operation consists in putting in place a clamp 12, well known in itself, which fits the underside of the part of the collecting plate forming the groove 4 and which extends along the rising edge 5 and including tabs 13 are crimped onto the top of the bar 10.

It is advantageous that the strip extends over the four sides of the collector plate. In addition, the top 10a of the bar is preferably located above the edge of the collector so that the fold 13a of the legs does not generate a line of fatigue.

Since the collector plates are most often of uniform width, it is advantageous, as illustrated in FIG. 3, to produce by molding bars 10 having the shape of a rectangular frame whose dimensions correspond to those of the largest collecting plate that can be used and these bars in the shape of rectangular frame are then cut to length, as illustrated for example by the section lines 14 shown in FIG. 3. It is obviously possible, if desired; to form bars in the shape of a rectangular frame for each type of exchanger, likewise, it would not go beyond the scope of the invention to manufacture half-frames whose sides would then be cut to length or by using sections of bars which would be arranged in the four sides of the groove of each collector plate.

Fig. 2 illustrates: a slight variant according to which the clamp 12: is. not used. In this case, it is the rising edge 5 of the collecting plate which is provided with tabs 13 crimped on the top of the bar 10. In this embodiment, the edge 10b at least of the bar is rounded so that the fold of the legs 13 be performed in good conditions.

Fig-4 = illustrates an embodiment, simplified. according to which the water box. 6 does not have: a rising edge 8 as in the previous embodiments, but is only surrounded by a flat edge 7a. In this case, a strip 10 is placed as above on the rim, the width of which corresponds to that of the rim 7a and the lugs 13 of the collector plate 3 are crimped as illustrated. in fig. 2 on the top of the bar.

In this embodiment, one could, in the same way, use the clamp 12 of FIG. t.

Figs. 5 and 6 illustrate a development of the invention which is implemented in the embodiment described above with reference to FIG. 2 but which can obviously apply to other embodiments.

According to this development, notches 15 with a curved, for example concave, bottom are formed in the bars and the tabs 13 are folded back in the notches and deformed corresponding to the bottom, which considerably increases the stiffness of the tabs.

In all cases, the bar which is made of hard material supports the forces due to crimping and distributes these forces over. the rim 7 or 7a of the water box, rim which is thus applied under uniform pressure on the seal 9.

The invention is not limited to the embodiments shown and described in detail, since various modifications can be made thereto without departing from its scope.

In particular, the water boxes can be made of synthetic material while having a thin wall which is normally deformable under the influence of the force usually applied by the tabs 13 if the bars 10 were not used. It is thus possible to manufacture water boxes at a much lower cost price than that of molded plastic boxes, the thickness of which must prevent any deformation of the part applied to the seal 9 by the tabs 13.

Claims (10)

1. Heat exchanger comprising a core of tubes (2) opening into tube plates (3) defining, at their periphery, a groove (4) bounded outside by a raising edge (5), a sealing gasket (9) being arranged in the bottom of the groove to be clamped by the underneath portion of a flange (7) that forms a header box (6) being with a thin wall and maintained either by crimping portions extending the raising edge of the tube plate or by an added clamp (12), characterized in that a smalf bar (10) is interposed between the top of the flange of this header box (6) and the crimping portions of the tube ptate (3) or of the added clamp (12).

2. Heat exchanger according . to claim 1, characterized in that the small bar (10) is made of a substantially non deformable hard material-

3 Heat exchanger according to one of claims 1 or 2, characterized in that the small bar (10) extends all around the tube plate (3) and the header box (6) which covers it.

4. Heat exchanger according to one of claims 1 to 3, characterized in that the small bar (10) is made of a part having the configuration of a rectangular frame, of a half frame or of rods the dimensions of which in cross-section correspond to those of the groove defined by the tube piate.

5. Heat exchanger according. to claim 4, characterized in that the rectangular frame-shaped or half-frame-shaped small bar (10) is produced in order to mate the dimensions of the largest tube plates (3) used in manufacture, and In that it is cut off at its sides in order to be adapted to tube plates (3) of smaller dimensions.

6. Heat exchanger according to one of claims 1 to 5, characterized in that the header box (6) has, beyond Its flange, a raising portion (8) and in that the small bar (10) has a thickness exceeding the height of said raising portion by forming a bead (11) covering the end of this raising portion.

7. Heat exchanger according to one of claims 1 to 6, characterized in that at least the edge (10b) of the small bar (10) which is turned toward the crimping portions is rounded.

8. Heat exchanger according to one of claims 1 to 7, characterized in that the crimping portion are made of lugs (13) folded back on the top of the small bars (10).

9. Heat exchanger according to one of claims 1 to 8, characterized in that the small bars (10) have, uprightly to the lugs, notches (15) with curved bottom on which are folded the lugs (13).

10. Heat exchanger according to one of claims 1 to 9, characterized in that the curvature of the bottom of the notches (15) is concave.

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