PLATE CONSTITUTING A HEAT EXCHANGER AND HEAT EXCHANGER COMPRISING AT LEAST ONE SUCH PLATE

Abstract

The invention relates to a channel intended for circulating fluid and formed by at least two plates each having a bottom and a section, the bottom extending in a first plane, the section extending in a plane that is parallel and offset with respect to the first plane, the bottom and the section being connected to one another by an intermediate portion, the bottom of at least one of the plates includes a first protuberance. The first protuberance extends from its base to its top wall. The top wall is in contact with the bottom of the opposite plate and partially faces the intermediate portion of the plate.

Description

TECHNICAL FIELD

The present invention relates to plates that form part of a heat exchanger. The subjects of the invention are such plates and a heat exchanger having at least one pair of such plates.

BACKGROUND OF THE INVENTION

In the automotive sector, it is common to have to control the temperature of an element such as an electric motor, a battery, a device for storing heat energy and/or cold energy or the like. To this end, the motor vehicle is equipped with an installation that comprises a refrigerant circuit inside which a refrigerant circulates, and a heat-transfer liquid circuit inside which a heat-transfer liquid circulates. The refrigerant circuit comprises a compressor for compressing the refrigerant, a thermal exchanger for cooling the refrigerant at constant pressure, an expansion member for allowing the refrigerant to expand, and a heat exchanger, which is arranged so as to allow thermal transfer between the refrigerant and the heat-transfer liquid. According to other applications, the motor vehicle can also comprise an exchanger for allowing thermal transfer between two refrigerants at different temperatures, or between two heat-transfer fluids at different temperatures.

The heat exchanger is an exchanger formed of plates that are stacked and joined together to form a tube delimiting a channel for circulating the refrigerant or the heat-transfer liquid. The plates comprise at least two openings, which are formed in a bottom of the plate, for supplying the circulation channel with heat-transfer liquid or with refrigerant. The circulation channel provides the heat-transfer liquid or the refrigerant with a passage section, which is a surface considered perpendicularly to a plane in which the plates extend and perpendicularly to an axis of longitudinal extent of the plates.

It is known practice to form protuberances inside the circulation channel in order to disturb a flow of the refrigerant and/or of the heat-transfer liquid inside the circulation channel. The protuberances are obtained through deformation, in particular by stamping, of at least one of the plates. Each protuberance comprises a base formed in the bottom of the plate and a top wall formed opposite the base.

During the phases of validating such a heat exchanger, the latter is subjected to mechanical strength tests. These tests, of the burst test or pressure cycle test type, for example, aim to ensure that the exchanger is able to withstand a certain pressure, beyond which pressure leaks appear.

The problem therefore lies in locating said leaks. Specifically, for these heat exchangers, this type of failure generally appears in the form of microleaks, most commonly situated in the core of the product, i.e. at the circulation channel. Tomography tests for locating these microleaks on heat exchangers after mechanical strength tests were inconclusive because said microleaks are not visible.

SUMMARY OF THE INVENTION

The aim of the present invention is therefore to designate a reference fracture zone for the mechanical strength tests on a heat exchanger with plates having protuberances. To this end, certain protuberances are specifically designed to generate a localized fracture.

More particularly, the invention relates to a channel intended for circulating fluid and formed by at least two plates, each of the plates comprising a bottom and a section, the bottom extending in a first plane, the section extending in a plane that is parallel and offset with respect to the first plane, the bottom and the section being connected to one another by an intermediate portion. Said channel is also characterized in that the bottom of at least one of the plates comprises a first protuberance, said first protuberance being characterized in that it extends from its base, which is formed in the first plane of the bottom of said plate, to its top wall, said top wall being in contact with the bottom of the opposite plate and partially facing the intermediate portion of said plate.

“Plane that is parallel and offset with respect to the first plane” is understood to mean a plane that is offset in a direction perpendicular to the bottom of the plate.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that at least one of the plates comprises at least one second protuberance, which extends from its base to a top wall, said top wall being in contact with the bottom of the opposite plate over the entirety of its surface.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the first protuberances and/or the second protuberances have a frustoconical shape.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the top wall of the first protuberances and/or of the second protuberances has a circular, rectangular, triangular or chevron-shaped section.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the top wall of the first protuberances and/or of the second protuberances extends in a plane parallel to the first planes of each of the plates.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the height of the protuberances is considered between the base and the top wall of said protuberance, this height being between 0.3 mm and 2.0 mm, and preferentially between 0.5 mm and 1.5 mm, ideally between 0.7 mm and 1.3 mm.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the plates have a rectangular shape.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that each of the plates comprises at least one raised edge, said raised edge surrounding the bottom.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the bottom and the raised edge of each of the plates delimit the channel for circulating fluid.

According to at least one of the aspects of the invention, the channel for circulating fluid is characterized in that the plates comprise two longitudinal raised edges formed facing one another and two lateral raised edges formed facing one another.

The invention also relates to a heat exchanger comprising a stack of plates according to the invention.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the stack of plates forms an alternating arrangement of first channels and of second channels, which are intended to circulate a refrigerant and a heat-transfer liquid, respectively.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the first planes in which the bottoms of the plates are inscribed are perpendicular to the stacking direction.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the section of each of the plates is in contact with the bottom of the opposite plate.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that each of the plates comprises at least four openings.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that each of these openings can be triangular, rectangular or circular.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that each of the sections of each of the plates comprises one opening. This has the advantage of producing the maximum mechanical stress during burst tests or pressure cycle tests and thus of promoting a potential fracture on the first protuberance. The inspection at the end of the tests will at least consist in verifying the behavior of this first protuberance.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the openings are distributed in pairs at each longitudinal end of the plate, and more particularly at each of the corners of the bottom of the plate. This has the advantage of simplifying the inspection at the end of the tests by making it possible to verify just one of the ends of the channel and by making it easier to access the first protuberance.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that two openings are configured to communicate with one of the first circulation paths formed on one side of the bottom, and the other two openings are configured to communicate with one of the second circulation paths formed on another side of the bottom.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the channel has an I-shaped profile.

According to at least one other aspect of the invention, the heat exchanger is characterized in that the bottom of the plates comprises a rib, which is arranged so that the channel has a U-shaped profile.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the protuberances are deformations of the plate.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the plates are formed by stamping.

According to at least one of the aspects of the invention, the heat exchanger is characterized in that the plates are made of a metallic material, which is for example able to be stamped in order to form, in particular, the protuberances by stamping of the plate, the metallic material being chosen from among the thermally conductive metallic materials, in particular aluminum or aluminum alloy.

The invention also relates to an installation intended for the thermal treatment for a vehicle of an element, it being possible for said element to be, in particular, an electric motor or combustion engine and/or a battery for storing electrical energy, said installation comprising at least one heat exchanger according to the invention.

BRIEF DESCRIPTION OF DRAWINGS

Further features, details and advantages of the invention will become more clearly apparent upon reading the description given below by way of indication with reference to drawings, in which:

FIG. 1 is a schematic view of an installation comprising at least one heat exchanger according to the invention,

FIG. 2 is a schematic view of a first heat exchanger participating in the installation shown in FIG. 1,

FIG. 3 is a partial schematic view of the first heat exchanger illustrated in FIG. 2, and

FIG. 4 is a schematic front view of a plate forming part of the first heat exchanger illustrated in FIGS. 2 and 3.

DETAILED DESCRIPTION OF THE INVENTION

It should first of all be noted that the figures set out the invention in detail for implementing the invention, it being, of course, possible for said figures to serve to better define the invention if necessary.

In FIG. 1, a motor vehicle is equipped with an element 1 that needs to be cooled or heated, for example in order to optimize the operation thereof. Such an element 1 is, in particular, an electric motor or combustion engine intended to at least partially propel the motor vehicle, a battery provided to store electrical energy, a device for storing heat energy and/or cold energy or the like. To this end, the motor vehicle is equipped with an installation 2 that comprises a refrigerant circuit 3 inside which a refrigerant 4 circulates, for example carbon dioxide or the like, and a heat-transfer liquid circuit 5 inside which a heat-transfer liquid 6 circulates, in particular glycol water or the like. The installation 2 comprises at least one heat exchanger 11, 12 according to the present invention. The installation 2 is described below in order to better understand the present invention, but the features of the described installation 2 are in no way limiting for the heat exchanger 11, 12 of the present invention. In other words, the installation 2 is able to have distinct structural features and/or operating modes that are different than those described, without the heat exchanger 11, 12 departing from the rules of the present invention.

The refrigerant circuit 3 comprises a compressor 7 for compressing the refrigerant 4, a refrigerant/external air exchanger 8 for cooling the refrigerant 4 at constant pressure, which is for example placed at the front end of the motor vehicle, an expansion member 9 for allowing the refrigerant 4 to expand, and a first heat exchanger 11, which is arranged so as to allow thermal transfer between the refrigerant 4 and the heat-transfer liquid 6. The refrigerant circuit 3 comprises a second heat exchanger 12, which is arranged so as to allow thermal transfer between the refrigerant 4 and an air flow 10, the air flow 10 circulating for example inside a conduit 13 of a heating, ventilation and/or air-conditioning system, before being delivered inside a passenger compartment of the motor vehicle.

To this end, the element 1 is in communication with a thermal exchanger 14, the thermal exchanger 14 being able to modify a temperature of the element 1, in particular by direct contact between the element 1 and the thermal exchanger 14, the thermal exchanger 14 forming part of the heat-transfer liquid circuit 5.

The heat-transfer liquid circuit 5 comprises a pump 15 for circulating the heat-transfer liquid 6 inside the heat-transfer liquid circuit 5. The heat-transfer liquid circuit 5 comprises the first heat exchanger 11, which also forms part of the refrigerant circuit 3. The first heat exchanger 11 comprises at least one first circulation path 21 for the refrigerant 4 and at least one second circulation path 22 for the heat-transfer liquid 6, the first circulation path 21 and the second circulation path 22 being arranged so as to allow heat exchange between the refrigerant 4 present inside the first circulation path 21 and the heat-transfer liquid 6 present inside the second circulation path 22. Preferably, the first heat exchanger 11 has several first circulation paths 21 and several second circulation paths 22. A first circulation path 21 is interposed between two second circulation paths 22, and a second circulation path 22 is interposed between two first circulation paths 21. The first heat exchanger 11 thus has an alternating arrangement of first circulation paths 21 and second circulation paths 22.

Inside the heat-transfer liquid circuit 5, the heat-transfer liquid 6 circulates from the pump 15 to the first heat exchanger 11, then circulates inside the first heat exchanger 11, using the second circulation paths 22 to exchange heat energy with the refrigerant 4 present inside the first circulation paths 21. The heat-transfer liquid then circulates in the thermal exchanger 14 in order to exchange heat energy with the element 1, then returns to the pump 15.

Inside the refrigerant circuit 3, the refrigerant 4 circulates from the compressor 7 to the refrigerant/external air exchanger 8, then to the expansion member 9.

According to a first operating mode of the refrigerant circuit 3, the refrigerant 4 then circulates inside the first heat exchanger 11, using the first circulation paths 21 inside which the refrigerant 4 exchanges heat energy with the heat-transfer liquid 6 present inside the second circulation paths 22, then returns to the compressor 7.

According to a second operating mode of the refrigerant circuit 3, the refrigerant 4 circulates inside the second heat exchanger 12, using circulation paths inside which the refrigerant 4 exchanges heat energy with the air flow 10, then returns to the compressor 7.

In FIG. 2, the first heat exchanger 11 is generally parallelepipedal and comprises an end plate 100a and an end plate 100b. The end plate 100a is provided with a heat-transfer liquid inlet 101 through which the heat-transfer liquid 6 enters the first heat exchanger 11. The end plate 100a is also provided with a heat-transfer liquid outlet 102 through which the heat-transfer liquid 6 is discharged from the first heat exchanger 11. The second circulation paths 22 extend between the heat-transfer liquid inlet 101 and the heat-transfer liquid outlet 102. The end plate 100a also has a refrigerant inlet 103 through which the refrigerant 4 enters the first heat exchanger 11, and a refrigerant outlet 104 through which the refrigerant 4 is discharged from the first heat exchanger 11. The first circulation paths 21 extend between the refrigerant inlet 103 and the refrigerant outlet 104.

In FIG. 3, from which the end plate 100b of the first heat exchanger 11 has been omitted, the first heat exchanger 11 is a plate exchanger that comprises a plurality of plates 105, such as the plates 105 depicted schematically in FIG. 4. The plate 105 extends primarily along a longitudinal axis of extent A1. The plate 105 comprises a bottom 106, and at least one raised edge 108a, 108b, 109a, 109b that surrounds the bottom 106. In other words, the raised edge 108a, 108b, 109a, 109b is formed at the periphery of the bottom 106, and the raised edge 108a, 108b, 109a, 109b surrounds the bottom 106. It will be understood that the plate 105 is arranged in a generally rectangular tub, the bottom of the tub being formed by the bottom 106, and the edges of the tub being formed by the raised edge 108a, 108b, 109a, 109b. More particularly, the raised edge 108a, 108b, 109a, 109b comprises two longitudinal raised edges 108a, 108b formed facing one another and two lateral raised edges 109a, 109b formed facing one another.

The plate 105 comprises four openings 110, it being possible for said openings 110 to be triangular. These openings 110 can also be, for example, circular or rectangular. These openings 110 are distributed in pairs at each longitudinal end of the plate 105, and more particularly at each of the corners of the bottom 106 of the plate 105. Two of these openings 110 are configured to communicate with one of the first circulation paths 21 formed on one side of the bottom 106, and the other two openings 110 are configured to communicate with one of the second circulation paths 22 formed on another side of the bottom 106.

Two of the openings 110 formed at the same longitudinal end of the plate 105 are each surrounded by a section 120, such that these openings 110 encircled by this section 120 extend in a first plane that is parallel and offset, in a direction perpendicular to the bottom 106 of the plates 105, with respect to a first plane P1 in which the bottom 106 is inscribed. The other two openings 110 situated at the other longitudinal end of the plate 105 extend in the first plane P1. The bottom 106 and each of the sections 120 of each of the plates 105 are connected to one another by an intermediate portion 119.

Two plates 105 are nested inside one another and in contact with one another at least by way of their raised edges 108a, 108b, 109a, 109b. In other words, two plates 105 are stacked one above the other and form between them a space that forms the channel 111a, 111b for circulating the refrigerant 4 or the heat-transfer liquid 6.

The bottom 106 comprises a rib 113, which is arranged such that the channel 111a, 111b has a U-shaped profile. The rib 113 is parallel to a direction D of extent of the longitudinal raised edges 108a, 108b, the direction D of extent of the longitudinal raised edges 108a, 108b being preferentially parallel to the longitudinal axis of extent Al of the plate 105. The rib 113 extends between a first longitudinal end 114 and a second longitudinal end 115, the first longitudinal end 114 being in contact with the raised edge 108a, 108b, 109a, 109b, and preferentially in contact with a first lateral raised edge 109a that the raised edge 108a, 108b, 109a, 109b comprises. The second longitudinal end 115 is situated at a first non-zero distance D1 from the raised edge 108a, 108b, 109a, 109b, the first distance D1 being considered between the second longitudinal end 115 and the raised edge 108a, 108b, 109a, 109b and measured along the axis of longitudinal extent A1 of the plate 105.

These arrangements are such that the channel 111a, 111b is shaped as a U where the branches of the U are parallel to the longitudinal raised edges 108a, 108b of the plate 105 and are separated by the rib 113, and where the base of the U lies next to a second lateral edge 109b that is formed longitudinally opposite the first lateral edge 109a.

In FIG. 4, three plates 105 are nested inside one another in such a manner that the raised edge 108a, 108b, 109a, 109b of one plate 105 is fitted inside the raised edge 108a, 108b, 109a, 109b of the immediately successive plate 105.

Such a stack of plates 105 is also formed in such a manner that the bottoms 106 of the plates 105 are arranged parallel to one another, with spaced-apart and stepped superpositioning of the bottoms 106. The raised edges 108a, 108b, 109a, 109b of two plates 105 fitted inside one another are in contact and are intended to be soldered to one another in order to ensure leaktightness of the channel 111a, 111b that is thus formed between two adjacent plates 105. Two adjacent plates 105 are also associated in such a manner that the grooves 113 in the two adjacent plates 105 are superposed on one another.

Two plates 105 nested inside one another in this manner jointly delimit a tube 123 that channels a circulation of the refrigerant 4 or else of the heat-transfer liquid 6. In other words, the two plates 105 forming the tube 123 jointly delimit the channel 111a, 111b dedicated to the circulation of the refrigerant 4 or of the heat-transfer liquid 6. More particularly, one side of a plate 105 borders the first channel 111a for circulating the refrigerant 4 and the other side of the same plate 105 borders the second channel 111b for circulating the heat-transfer liquid 6. Thus, the plates 105 are mutually arranged in such a manner as to configure the channels 111a, 111b for circulating the refrigerant 4 and the heat-transfer liquid 6 in an alternating arrangement.

Each of the plates 105 is advantageously provided with a plurality of protuberances 112a, 112b. Each of the protuberances 112a, 112b of one plate 105 extends from its base 117, which is formed in the first plane P1 of the bottom 106 of said plate 105, to its top wall 116. The top wall 116 is the wall of the protuberance 112a, 112b that is furthest from the bottom 106. The protuberances 112a, 112b are distributed in two categories.

Thus, each of the plates 105 comprises at least one first protuberance 112a, characterized in that the top wall 116 of said first protuberance 112a is in contact with the bottom of the opposite plate 105 and partially facing the intermediate portion 119 of said plate 105.

Each of the plates 105 comprises a plurality of second protuberances 112b. The top wall 116 of the second protuberances 112b is in contact with the bottom 106 of the opposite plate over the entirety of its surface.

The height H of the protuberances is considered between the base 117 of the protuberance 112a, 112b that is formed in the first plane P1 of the bottom 106 and the top wall 116 of said protuberance 112a, 112b. This height is between 0.3 mm and 2.0 mm, and preferentially between 0.5 mm and 1.5 mm, ideally between 0.7 mm and 1.3 mm.

Each of the plates 105 comprises four openings 110 and each of the sections 120 of each of the plates 105 comprises one opening 110. In addition, each of the sections 120 of each of the plates 105 is in contact with the bottom 106 of the opposite plate 105.

The plate 105 is made of a metallic material, which is able to be stamped in order to form, in particular, the protuberances 112a, 112b and the rib 113 by stamping of the plate 105, the metallic material being chosen from among the thermally conductive metallic materials, in particular aluminum or aluminum alloy.

Claims

1. A channel intended for circulating fluid and formed by at least two plates, each including a bottom and a section, the bottom extending in a first plane, the section extending in a plane that is parallel and offset with respect to the first plane, the bottom and the section being connected to one another by an intermediate portion,the bottom of at least one of the plates including a first protuberance, said first protuberance extending from its base to its top wall, said top wall being in contact with the bottom of the opposite plate and partially facing the intermediate portion of said plate.

2. The channel as claimed in claim 1, wherein at least one of the plates includes at least one second protuberance, which extends from its base to a top wall, said top wall being in contact with the bottom of the opposite plate over the entirety of its surface.

3. The channel as claimed in claim 1, wherein each of the plates includes at least one raised edge, said at least one raised edge surrounding the bottom.

4. The channel as claimed in claim 3, wherein the bottom and the at least one raised edge of each of the plates delimit the channel for circulating fluid.

5. A heat exchanger comprising a channel intended for circulating fluid and formed by at least two plates, each including a bottom and a section, the bottom extending in a first plane, the section extending in a plane that is parallel and offset with respect to the first plane, the bottom and the section being connected to one another by an intermediate portion, the bottom of at least one of the plates including a first protuberance, said first protuberance extending from its base to its top wall, said top wall being in contact with the bottom of the opposite plate and partially facing the intermediate portion of said plate.

6. The heat exchanger as claimed in claim 5, wherein the stack of plates forms an alternating arrangement of first channels and of second channels, which are intended to circulate a refrigerant and a heat-transfer liquid, respectively.

7. The heat exchanger as claimed in claim 5, wherein the section of each of the plates is in contact with the bottom of the opposite plate.

8. The heat exchanger as claimed in claim 7, wherein each of the plates includes at least four openings.

9. The heat exchanger as claimed in claim 8, wherein each of the sections of each of the plates includes one opening.

10. An installation intended for thermal treatment of an element of a vehicle, comprising at least one heat exchanger having a channel intended for circulating fluid and formed by at least two plates, each including a bottom and a section, the bottom extending in a first plane, the section extending in a plane that is parallel and offset with respect to the first plane, the bottom and the section being connected to one another by an intermediate portion, the bottom of at least one of the plates including a first protuberance, said first protuberance extending from its base to its top wall, said top wall being in contact with the bottom of the opposite plate and partially facing the intermediate portion of said plate.