FR3036179A1 - HEAT EXCHANGER MOLDED IN TWO PARTS AND METHOD OF MANUFACTURING SUCH EXCHANGER - Google Patents

Abstract

Heat exchanger comprising at least one hollow body, made of thermoplastic material, which delimits an internal cavity provided with an inlet and an outlet of a first fluid and which has an external surface provided with heat exchange portions with a second fluid. The hollow body comprises two half-bodies molded independently of one another and fixed to one another to have facing surfaces forming between them the internal cavity. Process for manufacturing such an exchanger

Description

FIELD OF THE INVENTION The present invention relates to the heat exchange means used in particular for the treatment of water and industrial effluents, for the recovery of heat in the recovery devices. eg energy from industrial sites, or any other application requiring heat exchange. The invention also relates to a method of manufacturing such a heat exchanger.

STATE OF THE ART Metallic heat exchangers are known, for example tubes having ends connected, on the one hand, to a first inlet manifold housing and, on the other hand, to a second collector housing. Release. The collectors are connected to a fluid circuit and the tubes are immersed in a second fluid so as to create a heat transfer between the first fluid and the second fluid. These metal heat exchangers are poorly suited to aggressive fluids, such as salt water and chemicals that corrode the heat exchanger. In addition, these exchangers are made by assembling tubes and collectors and are relatively expensive to manufacture. In order to overcome these disadvantages, it has been envisaged to use exchangers made of thermoplastic material, for example high-density polyethylene and polypropylene, which are more resistant to metals. x chemical attacks that the simplest structure possible to the are assembled in pairs simplicity of forms of the efficiency of trade forms rolled plates that by gluing or welding. The exchanger however limits thermal and the resistance to pressure, and therefore the performance of the exchanger.

It is known from FR-A-2960288 of the plastics exchangers having much better performance. These exchangers have been designed in the form of hollow bodies obtained by extrusion blow molding. These heat exchangers comprise at least one hollow body, made of thermoplastic material, which delimits an internal sealed cavity provided with an inlet and an outlet of a first fluid and which has an external surface provided with heat exchange portions. with a second fluid. This structure also allows a relative compactness of exchangers and compatible performance of many conditions of use. However, these heat exchangers accept only a relatively low pressure of the order of 1 bar and it is difficult to obtain large heat exchangers 15 other than by connecting hollow bodies to each other, which is detrimental for some applications. OBJECT OF THE INVENTION An object of the invention is to obviate at least in part the aforementioned drawbacks.

BRIEF SUMMARY OF THE INVENTION For this purpose, according to the invention, there is provided a heat exchanger comprising at least one hollow body, made of thermoplastic material, which delimits an internal cavity provided with an inlet and an outlet. a first fluid and having an outer surface provided with heat exchange portions with a second fluid. The hollow body comprises two half-bodies molded independently of one another and fixed to one another so as to have facing surfaces forming between them the internal cavity. It is understood that the hollow body of the invention is obtained by assembling at least two hollow portions which each delimit at least a portion of the internal cavity (hence their name "half-body") so that that the internal cavity results from the meeting of the 3036179 3 cavity portions delimited individually by the half-bodies. This structure allows a better control of the thicknesses of the surfaces of the hollow body and therefore a better control of heat exchange between the 5 fluids. The shapes and dimensions allowed by this structure also give the hollow body good resistance to pressure compared to current exchangers thermoplastic materials. Finally, such a structure allows complex shapes of the hollow body.

The half-bodies each advantageously comprise a plate having at least one main surface projecting from which extends at least one solid rib, rectilinear or not, parallel to the edges of the plate or not, to delimit the cavity portion: this Structure 15 can be easily manufactured in injection molding. According to a particular embodiment, the internal sealed cavity is divided into an inlet manifold connected to the inlet, an outlet manifold connected to the outlet and a plurality of channels each having an end connected to the inlet manifold and one end connected to the output collector. The channels make it possible to distribute the fluid in the hollow body and their walls furthermore provide a stiffening of the hollow body, favoring its resistance to pressure. This structure has a relatively large heat exchange area for a given volume and allows simple manufacture of a plurality of channels. Advantageously then, each channel is delimited by the surfaces of the half-bodies facing one another and two longitudinal ribs projecting from these surfaces, transverse bars projecting into the channel to disrupt the flow of the first fluid in the channel.

The relatively high heat exchange surface promotes heat exchange which is enhanced by the disturbances produced in the flow of fluid by the webs. The invention also relates to a method of manufacturing such an exchanger. This method comprises the steps of: - molding half-bodies each having a first surface and a second surface which are opposed and which are each provided with protruding ribs; Fastening a first of the half-bodies to a second of the half-bodies in such a way that the first surfaces of these half-bodies extend opposite one another and the ribs define at least one internal cavity between the first surfaces of the first and second half-bodies; attaching a third of the half-bodies to the second half-body in such a way that the second surfaces of these half-bodies extend facing one another and the ribs define at least one external cavity between the second surfaces of the third half-bodies; fixing a fourth of the second half-bodies and on the third half-body so that the first surfaces of these half-bodies extend facing one another and the ribs define at least one internal cavity between the first surfaces of the third and fourth half-bodies. This manufacturing process is particularly simple since it enables the exchanger to be assembled by stacking the half-bodies on one another as they are assembled. The manipulations are thus reduced. Other characteristics and advantages of the invention will emerge on reading the following description 3036179 of particular non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE FIGURES Reference is made to the accompanying drawings, among which: - Figure 1 is a schematic view of a water treatment plant comprising exchangers according to the invention; FIG. 2 is a perspective view of an exchanger according to a first embodiment of the invention; - Figure 3 is a perspective view in partial section of a hollow body of the exchanger; - Figure 4 is a hollow body view in section 15 along the plane IV of Figure 3; FIG. 5a is a view from above of one of the faces of one of the half-bodies forming this hollow body; FIG. 5b is a view from above of the other face of this half-body; FIGS. 6a to 6d are diagrammatic sectional views illustrating the assembly of the exchanger; FIG. 7 is a perspective view of an exchanger according to a second embodiment of the invention; FIGS. 8a and 8b are views identical to FIGS. 5a and 5b of one of the half-bodies forming this hollow body; - Figure 9 is a perspective view in partial section of the exchanger according to the second embodiment; - Figures 10 and 11 show a first variant of hollow body connection of an exchanger according to the first embodiment of the invention; FIGS. 12a, 12b show two other hollow body connection variants of an exchanger according to the first embodiment of the invention; - Figures 13a, 13b show two variants of hollow body connection of an exchanger according to the second embodiment of the invention; FIG. 14a is a perspective view in cross-section of an exchanger according to a third embodiment of the invention; - Figure 14b is in cross section of this exchanger; Figure 15 is a perspective view of a plate of the exchanger according to the third embodiment of the invention; Figure 16 is a perspective view of a plate of an exchanger according to a variant of the third embodiment; FIG. 17a is a perspective view of a liquid side of a half-body of an exchanger according to a fourth embodiment; Figure 17b is a perspective view of a gas face of this half-body; FIG. 18a is a perspective view of a liquid face of a half-body of an exchanger according to a variant of the fourth embodiment; Figure 18b is a perspective view of a gas face of this half-body; - Figures 19a and 19b are partial views similar to Figures 5a and 5b of one of the half-bodies forming the hollow body according to a variant of the first embodiment; Figure 20 is a partial perspective view of a half-body according to a variant of the invention; FIG. 21 is a partial perspective view of a half-body according to another variant of the invention; FIG. 22 is a partial view of a tool for assembling the half-bodies together; - Figures 23 to 26 are perspective views of half-body according to other embodiments of the embodiment of the exchanger according to the first embodiment.

DETAILED DESCRIPTION OF THE INVENTION With reference to the figures, the invention relates to a heat exchanger used for example in a fluid treatment plant. An example of an installation comprises exchangers 100 connected in series in a circulation circuit of a first fluid. In the exchanger 100A passes a second fluid, here a relatively hot moist gas, for heating the first fluid to cause condensation of the second fluid. Exchanger 100A is here a condenser. In the exchanger 100B passes a third fluid, here a relatively cold fluid, and the heat exchanger 100B will allow a heat transfer from the first fluid to the third fluid to heat the latter. Exchanger 100B is here a heater. A pump 110 is mounted on the first fluid circuit to circulate it. A fan 120 is mounted in the vicinity of the exchanger 100A to form a forced gas flow forming the second fluid passing through the exchanger 100A. The third fluid flows in a circuit 130, partially shown, comprising a pump 140. It will be understood that the installation may comprise other equipment not shown, and in particular filters. The exchanger 100A is here a liquid / gas exchanger, while the exchanger 100B is here a liquid / liquid exchanger. GAS-LIQUID VERSION - First Embodiment of the Invention With reference to FIGS. 1 to 6d, a heat exchanger 100 according to the first embodiment of the invention, usable to form the exchanger 100A, 3036179 8 comprises a plurality hollow bodies, generally designated 1, made of thermoplastic material, here polypropylene (PP) or high density polyethylene (HDPE). Other thermoplastic materials may of course be used depending in particular on the fluids used, the temperatures encountered ... For example, polypropylene (PP) or high density polyethylene (HDPE) are used for operating temperatures below 85 ° C. ° C approx. Vinyldiene polyfluoride (PVDF) is used for operating temperatures below 140 ° C and perfluoroalkoxy (PFA) is used for operating temperatures below 200 ° C. The thermoplastic material may incorporate heat conductive fillers to increase the thermal conductivity of the thermoplastic material. These fillers may in particular be in the form of lamellae, fibers and / or granules. Each hollow body 1 delimits an internal cavity 2 provided with an inlet 30 and an outlet 40 of the first fluid. The hollow bodies 1 are fixed to each other so that the inlets 30 of the internal sealed cavities 2 are connected to each other and the outlets 40 of the internal sealed cavities 2 are connected to each other.

Each hollow body 1 comprises two half-bodies 4 molded independently of one another and fixed to one another so as to have facing surfaces forming between them the internal cavity 2. The half-bodies 4 are identical to each other and have substantially a flat plate shape, here substantially square, having two main faces, namely a surface 5 provided with heat exchange means 6 with the first fluid and a surface 7 provided with exchange means thermal 8 with the second fluid. The half-bodies 4 are attached to each other such that the surfaces 5 extend facing one another and the surfaces 7 extend opposite one another. It will be noted, however, that the half-bodies 4 at both ends of the body stack 4 have their surfaces 7 facing outward. The inlet 30 and the outlet 40 are each delimited by a tubular wall projecting from the surfaces 5, 7: the tubular wall is interrupted on the side of the surface 5 to provide an opening 30 'permitting the passage the first fluid on the surface 5 and is continuous on the side of the surface 7 to prevent the passage of the first fluid on the surface 7. The inlet 30 and the outlet 40 are arranged in two consecutive corners of the half-body 4.

Each pair of facing surfaces 5 comprises projecting rims 31 for defining the internal cavity 2 and is arranged in such a way that the internal cavity 2 is divided into an inlet manifold 9 connected to the internal cavity 2. 30, an outlet manifold 20 connected to the outlet 40 and a plurality of channels 11 each having an end connected to the inlet manifold 9 and an end connected to the outlet manifold 10. The flanges 31 define a closed contour of so that the internal cavity 2 is a sealed cavity.

The heat exchange means 6 comprise ribs 6.1 and bars 6.2 projecting from the surfaces 5. Each channel 11 is thus delimited by the facing surfaces 5 of one another and two ribs 6.1. The bars 6.2 extend transversely 30 projecting in the channel 11 to disturb the flow of the first fluid in the channel 11. The bars 6.2 extend transversely to the ribs 6.1 from each of the two surfaces 5 of the half-bodies 4 facing each other. one from the other. The bars 6.2 of one of the surfaces 5 alternating with the bars 6.2 of the other of the surfaces 5.

The bars 6.2 are spaced a distance substantially equal to a spacing of the ribs 6.1 delimiting the channel 11. The bars 6.2 have a height substantially equal to one quarter of the spacing between the surfaces 5 of the half-bodies 4 in look at each other. Ribs 6.3 extend in a fan in the inlet manifold 9 from the inlet 30 to the channels 11 to distribute the first fluid from the inlet 30 to the set of channels 11. Other ribs 6.3 10 s extend fanwise in the outlet manifold 10 from the outlet 40 to the channels 11 to return the first fluid from the set of channels 11 to the outlet 40. The ribs 6.3 extend perpendicular to the ribs 6.1 and are connected each at one of the ribs 6.1 by a bend. For each pair of surfaces facing each other, the flanges, the tubular walls, and the ribs 6.1, 6.3 of one of the surfaces 5 are sealingly assembled to the flanges, tubular walls, ribs 6.1 and 6.3 of the other surfaces. 5. The hollow bodies 1 are fixed to each other and have flanges 32 to delimit between them an external cavity 22 provided with an inlet 23 and an outlet 24 of the second fluid.

Each pair of surfaces 7 facing each other defines the outer sealed cavity 22. The outer cavity 22 is divided into a plurality of channels 25 which are parallel to the channels 11 and which each have an end opening to the 23 and an end opening at the outlet 24. The heat exchange means 8 comprise ribs 8.1, 8.3 and bars 8.2 projecting from the surfaces 7. Each channel 25 is thus delimited by the surfaces 5 facing each other and two 3036179 11 ribs 8.1. Each channel 25 is subdivided into channels 26 by the ribs 8.3 parallel to the ribs 8.1. The bars 8.2 extend transversely protruding into each channel 26 to disturb the flow of the first fluid in the channel 26. The bars 8.2 extend transversely to the ribs 8.1 from each of the two surfaces 7 of the half-bodies 4 facing each other. one from the other. The bars 8.2 of one of the surfaces 7 alternate with the bars 8.2 of the other of the surfaces 7. The bars 10 8.2 are spaced apart by a distance substantially equal to a spacing of the ribs 8.1, 8.3 delimiting the channel 26. The bars 8.2 have a height substantially equal to a quarter of the spacing between the surfaces 7 of the half-bodies 4 facing one another.

For each pair of surfaces 7 opposite, the flanges 32, the tubular walls, and the ribs 8.1, 8.3 of one of the surfaces 7 are joined to the flanges 32, tubular walls, ribs 8.1 and 8.3 of the other surfaces 7 the tubular walls being tightly joined to one another. The plates, flanges, ribs and bars are full. The ribs 6.1, 8.1, 8.3 being parallel to each other, the inlets 30, 23 and the outlets 40, 24 are arranged so as to cause a circulation of the first fluid in a direction opposite to the second fluid (countercurrent). Operation with a circulation of the two fluids in the same direction is possible (cocurrent) but is less efficient for exchanges.

The ribs and bars of the heat exchange means 6 and 8 promote the heat exchange between the first fluid and the second fluid but also contribute to stiffen the half-bodies 4 reinforcing the resistance thereof to the pressure. The number and the arrangement of the bars result from a compromise between the increase of the heat exchange, the resistance to pressure, the manufacturing constraints (support during molding), the nature of the fluid and the losses of generated loads. The exchanger is connected to the first fluid circuit by means of conventional connectors 33, 43 respectively mounted on the inlet and the outlet of the exchanger, which are themselves connected respectively to the inlets 30 and to the outlets 40 of the bodies. Hollow 1. Such a connection is shown in Figures 9 and 10. In Figure 10, the connectors 33 and 43 are angled connectors facing away from each other. In Figure 11, several exchangers are connected in series.

Two other connection examples are shown in FIGS. 12a and 12b. In Figure 12a, the connectors 33 and 43 are angled connectors oriented in the same direction. In FIG. 12b, the connectors 33 and 43 are straight connections.

The exchanger according to the first embodiment is intended to be placed in a gas stream in such a way that the gas enters the exchanger through the inlets 23 and leaves via the outlets 24. The manufacturing process of this exchanger The thermal process will now be described with particular reference to FIGS. 6a to 6d. The method comprises the steps of: molding half-bodies 4 each having a first surface 5 and a second surface 7 which oppose each other and which are each provided with edges 31, 32 and protruding ribs 6.1, 6.3, 8.1, 8.3; welding a first of the half-bodies 4 to a second half-body 4 in such a way that the first surfaces 5 of these half-bodies 4 extend facing one another and the flanges 31 define the internal cavity 2 between the first surfaces 5 of the first and second half-bodies 4 (Figures 6a and 6b); 5 - soldering a third of the half-bodies 4 on the second half-body 4 so that the second surfaces 7 of these half-bodies 4 extend facing one another and the flanges 32 define at least an external cavity 22 between the second surfaces 7 of the second and third half-bodies 4 (FIGS. 6c and 6d); soldering a fourth of the half-bodies 4 on the third half-body 4 so that the first surfaces 5 of these half-bodies 4 extend facing one another and the flanges 31 define at least one internal capacitance 2 between the first surfaces 5 of the third and fourth half-bodies 4; And so on. The positioning and the welding of the half-bodies between them are carried out by means of a tool here semiautomatic. These operations can also be performed differently, for example completely automatically. Preferably, the positioning of the second half-body 4 on the first half-body 4 is facilitated by reliefs of complementary shapes present on the surfaces 5 to cooperate together when the half-bodies 4 are approached one of the other in a correct direction to allow the correct positioning of the half-bodies 4 relative to each other. According to a first advantageous variant (see FIG. 19a), the reliefs in question 30 comprise at least one double fork 60 projecting from the surface 5 and projecting from one of the ribs 6.1 in order to frame one of the ribs 6.1 of FIG. the surface 5 of the half-body 4 opposite. In the same way (see FIG. 19b), the positioning of the third half-body 14 on the second half-body 4 is facilitated by reliefs of complementary shapes present on the surfaces 7 to cooperate together when the half-bodies 4 body 4 are approached from each other in a correct direction to allow the correct positioning of the half-bodies 4 relative to each other. The reliefs in question comprise at least one double fork 80 projecting from the surface 7 and projecting from one of the ribs 8.1 to fit one of the ribs 8.1 of the surface 7 of the half-body 4 facing each other. In a second variant shown in FIG. 20 and described in relation to the surface 5, the second variant possibly being combinable with the first variant, the reliefs in question comprise at least one stud 61, here rectangular, extending in protruding from the surface 5 and projecting from one of the ribs 6.1 to engage in a recess 62 formed in the rib 6.1 opposite the other half-body 4. Such reliefs may also be provided on the surfaces side 7.

The fixing of the half-bodies 4 between them is carried out by welding by means of a heating blade 500 on which the flanges and ribs of the surfaces 5 or 7 of the half-bodies 4 are applied for a time sufficient to allow their softening before the half-bodies 4 are applied against each other to perform the actual welding of the flanges and ribs. It will be noted that the bars 6.2, 8.2 are not positioned symmetrically with respect to a median axis of the half-body 4 extending parallel to the half-body 4 between the inlet 30, 23 and the outlet 40, 24 to obtain a offset by one half-step of the bars 6.2 surfaces 5 opposite and a shift of one-half of the bars 8.2 of the surfaces 7 opposite (this shift is clearly visible in Figure 4). Indeed, to assemble two half-bodies 4 with each other to form a body, one of the half-bodies 4 is turned around said axis so that the bars of this half-body 4 will be the tooling comprises a lower plate 200 5 for supporting the first half-body 4 and then the entire stack resulting from the assembly of the half-bodies 4 to each other and an upper plate 300 for applying the half-body 4 to be fixed against the half-body or bodies 4 supported by the bottom plate 200. The plates comprise means for facilitating the correct positioning of the half body, for example centering pins. The plates have portions to support the half-bodies 4 and prevent them from collapsing when the half-bodies 4 are applied against the blade 500 or against each other: the plates comprise for this purpose grooves for receiving the peripheral rim, the ribs and the bars of the half-bodies so as to bear between the ribs and the bars. The plates are also equipped with means for clamping the half-body with which they are in contact: these clamping means here preferably comprise cleats clinging to the peripheral edges of the half-body, over the entire length of these members. this. The molding of the half-bodies 4 is carried out by injecting the plastic material under pressure into a mold. According to an advantageous characteristic of the invention, the injection is immediately followed by a compression phase. Note that the exchanger according to this first embodiment 30 has particularly simple shapes that facilitate its manufacture. The exchanger according to the second embodiment will now be described with reference to FIGS. 7, 8a, 8b and 9. The elements of the second embodiment identical to one another. or analogous to those of the first embodiment will bear a numerical reference identical to the latter. The exchanger of the second embodiment, which can be used to form the exchanger 100B, is an exchanger in which the first and third fluids 10 are each channeled in a circuit. In this embodiment, each hollow half-body 4 comprises two identical surfaces 5 provided with flanges 31 and heat exchange means 6 comprising ribs 6.1, 6.3 and bars 6.2. To distinguish the surfaces 5 from each other, an index 1, 2 is associated with the reference numeral 5. Each half hollow body comprises two inputs 30.1, 30.2 and two outputs 40.1, 40.2. The inlet 30.1 and the outlet 40.1 are arranged in two consecutive corners 20 of the half-body 4; the inlet 30.2 and the outlet 40.2 are arranged in two other consecutive corners of the half-body 4. The inlet 30.1 and the outlet 40.1 are each delimited by a tubular wall projecting from the surfaces 5.1, 5.2: the wall tubular is interrupted on the side of the surface 5.1 to allow the passage of the first fluid and is continuous on the side of the surface 5.2 to prevent the passage of the first fluid between the surfaces 5.2. The inlet 30.2 and the outlet 40.2 are each delimited by a tubular wall projecting from the surfaces 5.1, 5.2: the tubular wall is interrupted on the side of the surface 5.2 to allow the passage of the second fluid and is continuous from the side of the surface 5.1 to prevent the passage of the second fluid between the surfaces 5.1.

The connection of the exchanger to the first fluid circuit is achieved by conventional connectors 33.1, 43.1 mounted respectively on the inlet and the outlet of the exchanger connected respectively to the inlets 30.1 and the outlets 40.1. The exchanger is as previously manufactured by means of a tool comprising a lower plate for supporting the first half-body 4 and then the entire stack resulting from the assembly of the half-bodies 4 10 to each other and a upper platen 300 (visible from below in Figure 22) to apply the half-body 4 to be fixed against the half-body 4 supported by the fixed plate. The plates have portions to support the half-bodies 4 and prevent them from sagging when the half-bodies 4 are applied against the blade or against each other: the plates have for this purpose grooves to receive the peripheral rim, the ribs (grooves 401) and the webs (grooves 402) of the half-bodies so as to bear between the ribs and the webs. Due to the displacement of a half-step of the bars 6.2 of a face 5 relative to the bars 6.2 of the other face 5 of the half-body, the plates 200 & 300 comprise two sets of grooves 402 intended to receive the bars 6.2 25 after each reversal. The grooves 402 of the first set of grooves 402 are thus shifted by half a step relative to the grooves 402 of the other set of grooves 402. The grooves 402 intended to accommodate the bars 6.2 are thus in total twice as many as 6.2 The plates are also equipped with means for clamping the half-body with which they are in contact: these clamping means here preferably comprise movable cleats (405 in FIG. 22). clinging to peripheral edges of the half-body, over the entire length thereof.

The connection of the exchanger to the fluid circuit is achieved by conventional connectors 33.2, 43.2 respectively mounted on the inlet and the outlet of the exchanger respectively connected to the inlets 30.2 and 5 to the outlets 40.2. Such a connection is shown in Figure 12a. In this figure, the connectors 33.1 and 43.1 are angled connectors facing away from each other; the connectors 33.2 and 43.2 are angled connectors oriented in the same direction. An alternative connection is shown in Figure 12b. In this figure, the connections 33.1, 33.2, 43.1 and 43.2 are straight connections. It should be noted that the hollow body and the half-bodies may have different shapes from those previously described. OTHER EMBODIMENTS Thus, in the third embodiment shown in FIGS. 14a, 14b, 15 and 16, the heat exchanger is of the type of exchanger 100A, that is to say liquid-gas. It is understood that the third embodiment is applicable to liquid-liquid type exchangers. In this third embodiment, the half-bodies are no longer in the form of flat plates but are in the form of corrugated plates. The corrugations constitute reliefs promoting heat exchange by disturbing the flow of the fluids. As before, ribs, such as ribs 6.1, 6.3, are provided projecting from the surfaces of the hollow bodies to distribute the fluid over all of these surfaces. It will be noted that the corrugations may have a relatively large height as shown in FIGS. 14a, 14b, 15 and 16 or on the contrary a relatively small thickness as represented in FIG. 26.

In Figs. 14a, 14b, 15, the inlet 30 and the outlet of the first fluid are arranged on two consecutive corners of the plates. In Fig. 16, the inlet 30 and the outlet of the first fluid are arranged on two opposite corners of the plates. In the fourth embodiment shown in FIGS. 17a, 17b, 18a and 18b, the half-bodies are no longer in the form of flat plates provided with ribs but in the form of plates alternating recesses and bumps in an arrangement similar to FIGS. that described in FR-A-2960288. These hollows and bumps are reliefs promoting heat exchange by disrupting the flow of fluids. In FIGS. 17a and 17b, the exchanger is of the type of exchanger 100A, that is to say liquid-gas, with, in two consecutive corners of the plate, an inlet 30 and an outlet 40 for the first fluid. It is understood that the fourth embodiment is applicable to liquid-liquid type exchangers.

Ribs 6.1, 6.3 are provided projecting from the surface 5 of the half-bodies 4 to distribute the fluid over the entire surface 5. Ribs 8.1 are provided projecting from the surface 7 of the half-bodies 4 to distribute and channel the At least in part along the surface 7. In FIG. 18, the exchanger is of the type of the exchanger 100A with, in two corners of the plate diametrically opposed to each other, an inlet 30 and an output 40 for the first fluid.

Ribbing 6.1, 6.3 is provided projecting from the surface 5 of the half-bodies 4 to distribute the fluid over the entire surface 5. Ribs 8.1 are provided projecting from the surface 7 of the half-bodies 4 to distribute and channel the At least partly along the surface 7.

Of course, the invention is not limited to the embodiments described but encompasses any variant within the scope of the invention as defined by the claims. In particular, the term "half-body" should not be interpreted as limiting the invention to the assembly of two parts each constituting a half of the body even if this embodiment is the preferred embodiment. One of the half-bodies may represent more than half of the body and the body may result from the assembly of more than two parts (for example two half-bodies and a peripheral belt). The positioning of the half-bodies 4 relative to each other prior to welding can be ensured by guide pins secured to the tooling. The half-bodies can be assembled to each other by another method of attachment than welding and for example by gluing, by clamping after interposition of the compressible seals (especially in the case of a thermoplastic material not suitable for welding or gluing). The half-bodies may comprise pins projecting from at least one of the main surfaces to oppose locally a collapse of the half-hollow bodies during welding. The channels of one of the main surfaces of the half-bodies may have different heights from those of the channels on the other of the main surfaces.

The heat exchange means may have a structure different from that described and for example not comprise bars or bars arranged differently, for example on only one of the facing surfaces.

The bars may be at 90 ° to the ribs or at a different angle. Thus, in FIGS. 23 and 25, the bars are in the form of chevrons. The bars can be replaced by 5 pads. The transverse bars may have a height substantially between a quarter and a half of a spacing between the surfaces of the half-bodies facing one another.

The ribs may have other shapes and for example be discontinuous such as the ribs 6.1 shown in Figs. 24 and 25. The half-bodies may also be free of protruding ribs.

The directions of circulation of the fluids may be opposite or identical. The inputs and outputs can be positioned in the corners of the plate or in another position, for example in the vicinity of the central axes of the plate.

Alternatively, as shown in FIG. 21, the opening in the tubular walls defining the inlet 30 and the outlet 40 is provided with studs 50 which are spaced from one another so that the fluid can pass between the pads. 50 and that the studs 50 50 can support the adjacent half-body by preventing excessive deformation thereof either when fixing the half-shells together, or during the welding of a connection, or because of the efforts exerted by one of the connections on this half-body.

The exchanger according to the first embodiment may be arranged in a sealed tank in which the second fluid circulates. Although the invention has been described in application to a particular fluid treatment plant, it is to be understood that the invention is not limited to this application but is, on the contrary, usable in any application involving a liquid-liquid or liquid-gas heat exchange, with or without condensation, and for example an energy recovery application.

Claims (15)

CLAIMS1) Heat exchanger comprising at least one hollow body, made of thermoplastic material, which delimits an internal cavity provided with an inlet and an outlet of a first fluid and which has an external surface provided with heat exchange portions with a second fluid, characterized in that the hollow body comprises two half-bodies molded independently of one another and fixed to each other to have facing surfaces forming between them the internal cavity. 2) An exchanger according to claim 1, wherein the hollow body is arranged so that the internal cavity is divided into an inlet manifold connected to the inlet, an outlet manifold connected to the outlet and a plurality of channels each having a end connected to the inlet manifold and one end connected to the outlet manifold. 3) Exchanger according to claim 2, wherein each channel is delimited by the surfaces of the half-bodies facing each other and two ribs projecting from these surfaces, transverse bars extending protruding in the channel to disrupt the flow of the first fluid in the channel. 4) exchanger according to claim 3, wherein the bars extend transversely to the ribs from at least one of the surfaces of the half-bodies facing one another. 5) Exchanger according to claim 4, wherein the bars extend transversely to the ribs from at least the two surfaces of the half-bodies facing one another, the bars of one of the surfaces alternating with the bars of the other surfaces. 3036179 24 6) exchanger according to claim 4, wherein the transverse bars are spaced a distance substantially equal to a spacing of the ribs. 7. Exchanger according to claim 4, wherein the transverse bars have a height substantially comprised between a quarter and a half of a spacing between the surfaces of the half-bodies facing each other. 8) An exchanger according to any one of the preceding claims, comprising at least two hollow bodies fixed to each other for defining between them an external cavity provided with an inlet and an outlet of the second fluid, the inlets of the internal cavities being interconnected and the outlets of the internal cavities being connected to one another. 15 9) Exchanger according to claim 8, comprising more than two hollow bodies fixed to each other to delimit between them at least two external cavities, the inlets of the outer cavities being connected to each other and the outlets of the outer cavities being interconnected. 20 An exchanger according to claim 8 or claim 9, wherein the hollow bodies are arranged such that each external cavity is divided into an inlet manifold connected to the inlet, an outlet manifold connected to the outlet and a plurality of channels each having an end connected to the input collector and an end connected to the output collector. 11) An exchanger according to any one of the preceding claims, wherein the half-bodies are fixed to each other by a weld. 30 12) A method of manufacturing a heat exchanger, comprising the steps of: - molding half-bodies of thermoplastic material, each having a first surface and a second surface which are opposed and which are each provided with ribs protruding; attaching a first of the half-bodies to a second half-body in such a way that the first surfaces of these half-bodies extend facing one another and the ribs define at least one internal sealed cavity between the first surfaces of the first and second half-bodies, the inner cavity having an inlet and an outlet for a fluid; Fixing a third of the half-bodies on the second half-body so that the second surfaces of these half-bodies extend facing one another and the ribs define at least one sealed cavity external between the second surfaces of the second and third half-bodies; fixing a fourth of the half-bodies on the third half-body in such a way that the first surfaces of these half-bodies extend facing one another and the ribs define at least one internal sealed cavity between the first surfaces of the third and fourth half-bodies, the inner cavity having an inlet and an outlet for a fluid. 13) The method of claim 12, wherein the fixing of the half-bodies together is performed by welding. 14) The method of claim 12, wherein the molding is performed by injection. 15) The method of claim 14, wherein the injection is followed by a compression phase. 30