Abstract:
A heat exchanger for a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger, is characterized in that at least one of the first and second longitudinal ends ( 92 ) of at least one partition plate ( 20 ) and/or of at least one end plate ( 9 ) is coupled to at least one of the first and second ends of a said orientation plate ( 2, 20 ) by means of a damper element ( 94, 95 ).

Description:
FIELD OF THE INVENTION 
     The present invention relates to a heating, ventilation and/or air-conditioning device. 
     BACKGROUND OF THE INVENTION 
     Heating, ventilating and/or air conditioning devices are known having a thermal loop equipped with an evaporator, said evaporator consisting of a stack of plates having opposite first and second longitudinal ends some of which have separation elements intended to divert a flow of cooling liquid circulating in an axial direction of the evaporator so as to direct it to a channel region in which it travels from one said end to the other in a longitudinal direction of the plates. 
     The partition plates and, more generally, the chamber passages in evaporators with brazed plates are designed to meet the requirements of mechanical strength and to promote a balanced distribution of the cooling fluid in the various channels. Likewise, the parts of the coolant ducts close to the inlet and outlet manifolds meet the same requirements, while also seeking to promote turbulence of the flow in order to intensify the heat exchanges. 
     In its current design, which makes it possible to reconcile mechanical strength and high level of heat exchange, the geometry is a source of turbulence and of breakaway flow of the cooling fluid which are likely to generate noise emission causing discomfort for the user. 
     The present invention proposes to reduce the flow noise which is generated on the outside by the evaporator. 
     To this end the invention proposes to limit the vibratory excitation of the partition plates or even of the end plates. 
     The basic idea of the invention, according to a first aspect, is to limit the excitation in the regions where the cooling fluid arrives on the walls of the exchanger with a speed component perpendicular to the wall, this being obtained by adding stiffening elements which make it possible to limit the response of the wall to the frontal impacts of the fluid. 
     SUMMARY OF THE INVENTION 
     According to a first aspect the present invention provides a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger, said heat exchanger consisting of a stack of orientation plates having first and second opposite longitudinal ends defining channel regions between them in which a cooling fluid travels from one said end to the other in a longitudinal direction of the orientation plates, the first and the second longitudinal ends of the orientation plates having means for directing a flow of the cooling liquid either in an axial direction of the evaporator or, by diverting it, in a longitudinal direction of the orientation plates, in a said channel region, certain orientation plates being axial-orientation plates, and certain orientation plates being partition plates which, at least at one of their ends, divert the said flow of cooling liquid into a said channel region, the heat exchanger also having end plates arranged at its two opposite axial ends, wherein at least one of the first and second longitudinal ends of at least one partition plate and/or of at least one end plate is coupled to at least one of the first and second ends of a said orientation plate by means of a damper element. 
     This makes it possible to reduce the vibratory amplitudes and/or to guide the fluid. 
     Heat exchangers generally have a rectangular shape the largest dimension of which is parallel to the direction of the non-diverted flow of the cooling fluid. The orientation plates are generally rectangular and have a length which is parallel to the direction of flow of the fluid in the channels. 
     The invention applies also to other geometries. That being so, in the sense of the present application, the term “axial” is understood as designating the direction of flow of the cooling fluid when it is not diverted by an orientation plate, and the term “longitudinal direction of the orientation plates” is understood as the general direction of flow of the fluid along the channel or channels, from one longitudinal end of the plates to the other. 
     According to a first embodiment, at least some of said orientation plates are partition plates which, at least at one end, have at least one separating wall constituting a said separation element and which have at least one rib which constitutes a said stiffening means. 
     According to a second embodiment, at least some orientation plates are plates called standard plates having, at their first and second ends, at least one boss provided with an aperture allowing axial passage of the cooling liquid and at least certain orientation plates are substantially flat and, at least at one end, have at least one separating wall the thickness of which is greater than twice the thickness of said standard plates, this thickness advantageously being at least equal to the thickness of an end plate, and which constitutes a said stiffening means. The plate may have a substantially constant thickness, or the separating wall may even have a thickness greater than that of the rest of the plate. It is particularly advantageous for the separating wall to be profiled in such a way as to guide the cooling fluid from said axial direction of the evaporator to said longitudinal direction of the plates, which makes it possible to reduce the noise by at least partly preventing the impact due to said speed component. 
     According to a third embodiment of the invention in its first aspect, the heat exchanger, for example an evaporator, consists of a stack of said standard plates and of partition plates having, at their first and second ends, at least one boss having a bearing face at least one of which has a separation element and at least one flat plate is interposed between the bearing faces of the bosses of two partition plates. 
     According to another embodiment of the invention in its first aspect, the evaporator consists of a stack of said standard plates, which have a first face, particularly a flat face, and a second face, particularly a flat face, from which said bosses extend, and at least some of said flat plates are interposed between the first faces of two standard plates in such a way as to define two cooling-fluid passage half-channels, one between the first face of one of said two standard plates and a first face of said flat plate and the other between the second face of said flat plate and the first face of the other of said two standard plates. 
     At least one said flat plate may have at least one cooling-fluid axial passage aperture at one end. 
     According to another embodiment of the invention in its first aspect, a said stiffening means is a stiffening plate which is interposed between a said end of two plates and which is secured to them. 
     The embodiments given above make it possible to deal with the problem of the noise from the partition plates, but the invention, in its first aspect, applies equally to the case of the end plates and, to this end, at least one end plate includes at least one said stiffening means. 
     According to one embodiment, this stiffening means is a stiffening plate integral with one end of said end plate. 
     According to another embodiment, said stiffening means consists of an edge of the end plate which is folded onto one face of said end plate. Alternatively, at least one transverse edge and/or a longitudinal edge projecting from the end plate may be folded against at least one lateral surface of the heat exchanger. 
     According to a second aspect, the invention envisages reducing the noise generated by the end plates by decoupling them from the mechanical stresses which they receive. 
     According to its second aspect, the invention relates to a heating, ventilation and/or air-conditioning device including a thermal loop equipped with a heat exchanger, for example an evaporator, said heat exchanger consisting of a stack of orientation plates having opposite first and second longitudinal ends and defining channel regions between them in which a cooling fluid travels from one said end to the other in a longitudinal direction of the orientation plates, the first and the second longitudinal ends of the orientation plates having means for directing a flow of the cooling fluid, either in an axial direction of the evaporator, or, by diverting it, in a longitudinal direction of the orientation plates in a said channel region, certain orientation plates being axial-orientation plates, and certain orientation plates being partition plates which, at least at one of their ends, divert said flow of fluid in a said channel region, the heat exchanger also having end plates arranged at two opposite axial ends of the evaporator, characterized in that at least one of the first and second longitudinal ends of least one partition plate and/or of at least one end plate is coupled respectively to at least a first and second end of a said orientation plate (which may or may not be a partition plate) by means of a damper element. This damper element may be a stamped boss integral with the corresponding end of the end plate. This damper element may also be a corrugated metal sheet. At least one damper element is advantageously integral with a stiffening means, in such a way as to combine the damper effect and the stiffening effect, for example that obtained by a ribbed separating wall. 
     According to a third aspect, the invention envisages reducing the noise generated by the end plates by reducing the acoustic coupling thereof with the outside of the heat exchanger, for example an evaporator. This is because the end plates are generally brazed along a contour and have free regions which project from the outside or the inside of this contour and which are not fixed to the rest of the evaporator. When the end plates are subjected to the impact due to the circulation of the cooling fluid, these projecting regions are stressed by the vibrations thus produced and are also set into vibration, which induces an acoustic coupling with the outside which is all the greater if the surface area in question is itself substantial. 
     The basic idea of the invention in its third concept is to reduce or even to eliminate the influence of these projecting regions which are not fixed to the evaporator. 
     To that end, the invention relates to a heating, ventilation and/or air-conditioning device including a thermal loop equipped with an evaporator, said evaporator consisting of a stack of orientation plates having opposite first and second longitudinal ends and defining channel regions between them in which a cooling fluid travels from one end to the other in a longitudinal region of the plates, the first and the second longitudinal ends of the orientation plates having means for directing a flow of cooling liquid either in a direction axial to the evaporator, or in a longitudinal direction of the plates in a said channel region, the evaporator having end plates arranged at two opposite axial ends of the evaporator and at least a part of which, particularly of the contour, is secured, particularly by brazing, to an orientation plate, characterized in that at least one end of said part, particularly of the contour, has no region which is not secured to the orientation plate. 
     According to a first variant, at least one outer edge of said part of the contour has a folded edge running along it which is secured to said orientation plate. According to a second variant, at least one edge of said part of the contour constitutes one edge of an aperture formed in an end plate. The surface area of said aperture is advantageously equal to 20% of the total surface area of the end plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the invention will emerge better upon reading the description which will follow, given by way of non-limiting example in connection with the drawings, in which: 
     FIG. 1 represents an orientation plate constituting a plate called a standard plate, which is known in itself; 
     FIG. 2 a  represents an orientation plate constituting a partition plate having a separating wall according to one embodiment of the invention; 
     FIG. 2 b  represents an embodiment of the invention employing a separating wall; 
     FIGS. 3 a  to  3   c  represent three embodiments of the invention employing what are called flat separating plates; 
     FIG. 4 represents an embodiment of the invention employing an additional mass interposed between orientation plates; 
     FIGS. 5 a  to  5   d  respectively represent a detail of one end of an evaporator according to the prior art, and three embodiments employing end plates coupled to additional masses; 
     FIGS. 6 a  and  6   b  represent two embodiments allowing decoupling of the end plates with respect to the rest of the evaporator; 
     FIGS. 7 a  to  7   d  respectively represent a detail of one end of an evaporator according to the prior art, and three embodiments aiming to reduce the noise generated by a said end plate, according to three embodiments of the invention; 
     FIGS. 8 a  to  8   c  respectively represent an end plate according to the prior art and two embodiments of an end plate according to the invention, making it possible to reduce the noise emitted by said plates. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the various figures, like reference numerals refer to like parts. 
     According to FIG. 1, an orientation plate, called standard plate, has, at each of its longitudinal ends, a pair of bosses  15 , each of which has an aperture  16  allowing a cooling fluid to pass in an axial direction of the evaporator. These stamped bosses  15 , which are directed rearwards of FIG. 1, are connected by recessed channels  14 , delimited laterally by a longitudinal edge  11  of the plate  1  and separated from each other by a stamped central longitudinal rib  17 . The face  18  (which is seen in FIG. 1) carries the abovementioned channels  14  while the opposite face  19 , which is substantially flat in its central region, is bordered at its edges by projecting bosses  15 , as FIG. 3 a  shows better. 
     FIG. 2 a  represents an orientation plate which constitutes a partition plate  20  and which is distinguished from the plate  1  by the presence, at least at one of the longitudinal ends, of a separating wall  26  which constitutes the bottom of a stamped boss  25  and which prevents the cooling fluid passing axially, and which constrains it to be redirected in a longitudinal direction of the plate in channel regions  24 . 
     In other words, a heat exchanger such as an evaporator consists of a stack of orientation plates some of which are axial-orientation plates (or standard plates) and some of which are partition plates which, at least at one of their ends, divert the axial flow of the cooling liquid so as to supply the channels. The axial ends of the evaporator are equipped with end plates. 
     In order to reduce the noise generated by the axial impact of the cooling fluid on the separating walls  26 , they, according to the invention, are stiffened by means of ribs  26 ′ which are stamped at the same time as the partition plate  20  (or which are molded in plastic when the plates of the evaporator are of plastic). 
     By convention, a partition plate will be referenced  2  if it has a non-ribbed separating wall  26 , in accordance with the prior art. If it has a separating wall  26  provided with ribs  26 ′, it will be referenced  20 . 
     FIG. 2 b  shows a stack of orientation plates called standard plates  1  and of partition plates  20 . This stack of plates is produced in a way which is known in itself and defines, on the one hand, two feed channels  3  and  3 ′ situated at the longitudinal ends of the plates and oriented in an axial direction of the evaporator (arrow F), and, on the other hand, channel regions  4  oriented in a longitudinal direction of the plates (arrow F′) between a face  18  of a plate  1  and a face  28  of a plate  2 , that is to say that each longitudinal channel  4  of the plates consists of two half-channels facing each other,  14  and  28 . The bosses  15  and  25  are mounted head-to-tail and between them is trapped a corrugated sheet  5  generally called “fins” which serves in the conventional way to perform the thermal exchanges of the evaporator. 
     In the context of the invention, the bosses  25  of the plates  20  have separating walls  26  provided with ribs  26 ′. 
     The ribs  26 ′, represented in FIG. 2 a , have a lattice shape; this shape is given only by way of example, any shape stamped on the bottom  26  of the bosses  25  being capable of carrying out the same function. 
     According to one embodiment represented in FIG. 2 b , the face  29  of a first partition plate  20  is assembled against the face  19  of a second partition plate  20  in such a way that the recess formed by the rib  26 ′ of the first partition plate is in communication with the recess formed by the rib  26 ′ of the second partition plate. In this embodiment example, the change of direction of the flow is carried out with the aid of two partition plates. 
     According to another embodiment example (not represented), the face  29  of the partition plate  20  including ribs  26 ′ is interposed between the face  19  of a standard orientation plate  1  and the face  18  of another standard orientation plate  1 . In this embodiment, the change of direction of the flow is carried out with the aid of a single partition plate  20 . 
     Another means of reducing the noise is to interpose thicker plates or plates exhibiting overthicknesses in the region of the closed end. 
     FIG. 3 a  represents an embodiment of the invention in which the evaporator includes plates called standard plates  1 , stacked alternately in one direction and the other, that is to say that the bosses  15  are situated alternately on the left side and on the right side of the plate. Fins  51  and  52  are arranged between the faces  19  of two adjacent plates  1  the bosses  15  of which face each other with their apertures  16  being aligned. Between the faces  18  of adjacent plates  1  one or more thick partition plates  6  are arranged, which are substantially flat, which are closed at one of their longitudinal ends  60  and which exhibit an aperture  61  at their other end. These plates  6  are thick plates which have a thickness e at least twice the thickness (a few tenths of mm) of the sheet metal constituting the plates  1  and which is advantageously greater than the thickness e′ of an end plate, which is about 1 mm. The plates  6  are inserted between two adjacent orientation plates, then brazed to them. 
     As FIG. 3 a  shows, the assembly defines two half-channels  7  and  7 ′ separated in the region of the axial channel  3  and which communicate with each other via the aperture  61 , in the region of the axial channel  3 ′. 
     In the embodiment of FIG. 3 b , the plates  1  and  2  (or else  20 ) are stacked as represented and a thick flat plate  65 , closed at one longitudinal end and open via an aperture  66  at its other longitudinal end, is brazed between the bosses  25  of two partition plates  2  (or  20 ). This thick plate  65  constitutes a stiffener element which reduces the acoustic emission due to the impact on the bulkhead  26  of the cooling liquid originating from the channel  3  in the direction of the arrow F. A corrugated metal sheet  53  is arranged between one face  29  of a plate  2  and one face of the plate  65  and another corrugated metal sheet  54  is arranged between the other face of the sheet  65  and the face  29  of the plate  2 . 
     FIG. 3 c  represents an embodiment which is distinguished from FIG. 3 a  by the fact that the plate  6  has an overthickness  67  at its longitudinal end in the region of the axial channel  3 . According to one embodiment represented in FIG. 3 c , the overthickness  67  exhibits a convex profile  68 , which is able to facilitate the redirecting of the axial flow towards the channels  7  and  7 ′, preventing the fluid striking the plate  6  perpendicularly. 
     According to a second embodiment (not represented), this overthickness  67  advantageously exhibits a concave profile so as to channel and to guide the fluid towards the channel  7 . 
     FIG. 4 represents a stack of plates  1  and  2  which is produced in the same way as in the case of FIG. 3 c , but in which the plate  65  is replaced by a thick plate  70  which extends over the width of the corresponding longitudinal end. The bosses  25  of the plates  2  have a lower height at this end than at the other end, so as to take account of the thickness of this plate  70  (for example 1 mm or more). 
     The plate  6 , the overthickness  67  as well as the plate  70  are molded either in metal such as steel or aluminum or in a flexible material such as polymer or rubber. 
     FIG. 5 a  represents the end of an evaporator according to the prior art. An end plate  9  has stepped features  91  at each of its longitudinal ends which are extended by flat regions  92  which are brazed to the bosses  25  of partition plates  2 , a corrugated metal sheet  5  being trapped between the end plate  9  and the face  29  of the plate  2  for the thermal exchanges between the evaporator and its environment. 
     According to the invention, and as represented in FIG. 5 b , a small plate  93  is brazed to the outer faces  98  of the flat regions  92  so as to constitute a stiffener element able to reduce the noise generated by the axial impact of the fluid on the solid faces  26  of the plate  2  (or  20 ). 
     In the variant of FIG. 5 c , the end plate  9  is flat and the thick end plates  90 ′ are arranged between them and the bosses  25  of the partition plate  2  (or  20 ). 
     FIG. 5 d  is distinguished from FIG. 5 c  by the fact that the small end plates  90  are replaced by small plates  90 ′ of greater thickness, while the bosses  25  for their part are replaced by bosses  24  of lower height, while keeping the same space available for the corrugated metal sheet  5 . 
     Moreover, the protruding transverse  96  and/or longitudinal  97  ends of the end plate  9  are folded and brazed along additional masses and/or fins. 
     FIG. 6 a  illustrates a second concept according to the invention. A flat end plate  9  is brazed to fins  5  exhibiting, at each of their longitudinal ends, a region of height h which extends over a length corresponding approximately to the transverse dimension of the bosses  25  and, in the central part, a region of height H which extends over a length corresponding approximately to the length of the channels  4 . This allows a decoupling by damping between the plate  9  and the bosses  25  of the orientation plate  2  (or  20 ). 
     According to FIG. 6 b , the plate  9  is decoupled by bosses  95  which provide damping of the transmission of the vibrations from the orientation plate  2  (or  20 ). 
     The bosses  95  may consist of an orientation plate  1 ,  2  or  20  which is interposed between a partition plate  2  (or  20 ) and the end plate  9 , the plate  9  being brazed against the face  28  of the orientation plate  1 ,  2  or  20 . In this case, the bosses  25  of the partition plate are brazed against the bosses  25  of the orientation plate  1 ,  2  or  20 . Advantageously, two partition plates  20  including ribs  26 ′ are assembled in such a way that the recess formed by the rib  26 ′ of one partition plate is in communication with the recess formed by the rib  26 ′ of the other partition plate. 
     This decoupling by damping reduces the transmission of the noise to the end plates  9  and thus the acoustic emission produced by the plates  9 . 
     As FIG. 7 a  shows, the flat end regions  92  in which the end plate  9  is brazed to the partition plate  2  exhibit projecting parts or rims  96  which protrude outwards beyond the boss  25  of the partition plate  2 . According to the embodiment of FIG. 7 b , this rim  96  is eliminated so that the plate  9  exhibits edges  99  which do not extend beyond the contours over which the plate  9  is secured to the bosses  25 , or else, preferably, as represented in FIG. 7 c , it is folded onto the face  98  of the flat region  92 . The end plate  9  also represented in FIG. 8 a  may also exhibit projecting longitudinal regions  97  which, according to the invention, are advantageously folded over and brazed to a lateral face of the evaporator. The central region of the end plate  9 , which is not secured to the evaporator, is liable to constitute an acoustic-coupling region of significant surface area. According to the invention, it is proposed to eliminate it by forming a cut-out  108  of rectangular contour  100 ,  101 . According to another embodiment, the end plate  9 , represented in FIG. 8 b  includes a central cut-out  108  and its projecting transverse  96  and longitudinal  97  ends have been eliminated. 
     The end plate  9  which is represented in FIG. 8 c , for example, no longer exhibits regions which are not secured either outwards, since the projecting regions  96  and  97  have been folded over and brazed to the bosses  25  of the partition plate  2 , or inwards since the cut-out  108  has been formed. It will be noted that, whereas the embodiment of FIG. 8 c  provides for folding-down and brazing of the projecting regions  96  onto the boss  25 , it is also possible to carry out this folding onto the plate  9 , as in FIG. 7 c.    
     Advantageously, the cut-out surface  108  represents more than 20% of the surface area of a face of an orientation plate (or of a conventional end plate). This is because, in order to reduce the vibratory excitation of the end plates, it is necessary to take away the maximum amount of material of the plate. The remaining part of the plate protects the fins during the brazing process. The remaining part of the plate, represented in FIG. 8 b , has the shape of a frame, but this shape, however, is not in any way limiting; the remaining part possibly being formed by one or more strips which intersect (as represented in dashed line at  120  in FIG. 8 b ). These strips are secured at  121 , for example up to their edges  122 , to an orientation plate. 
     The embodiments described above make it possible to limit the vibratory excitation of the partition plates and/or of the end plates by taking account of the phenomena of vibratory excitation which are due to the impact of the cooling fluid on the walls of the exchanger with a speed component perpendicular to the wall. 
     Such a plate-type exchanger can thus fulfil two uses: 
     either as evaporator for motor-vehicle air-conditioning systems, 
     or as a gas-gas exchanger or evaporator for a combined motor-vehicle air-conditioning and additional thermodynamic heating system. 
     It will be noted that the embodiments described can be implemented by a stamping technique which does not carry any additional cost by comparison with the solutions currently employed.