Patent Application
20140151006
The invention involves the field of heat exchangers between two fluids, in particular for cooling a flow of air by means of heat exchange with a cooling fluid.
Such heat exchangers are used in the field of air conditioning, for example, of motor vehicles, and are in particular evaporators for an air conditioning circuit of a vehicle. They allow the heat to be exchanged between a first fluid, in particular air, and a second fluid, for example, a cooling fluid. They comprise a bundle of tubes which are intended for the circulation of the second fluid and which are arranged in a parallel manner in one or more rows, inlet and/or outlet cross-members for the second fluid in the tubes, and spaces between the tubes for the circulation of the second fluid.
Document FR2929388A1 discloses a heat exchanger whose tubes are produced by means of the assembly of a first plate and a second plate which are identical to each other, each having a concavity which is directed one towards the other, and a respective peripheral edge which is fitted to the other in a sealed manner in order to create a fluid circulation pipe, called a tube, which is sealed with respect to the cooling fluid and which allows it to circulate therein. Such exchangers therefore comprise a plurality of plates which are stacked from one side to the other of the exchanger in order to form a tube bundle. Each tube has two ends and consequently each plate also has two ends.
Such tubes have, for example, in the region of the ends thereof, a fluid distribution zone, also called a collection space, which allows the cooling fluid to be collected and distributed.
Each plate is thus provided with a dished member which delimits the fluid distribution zone in the exchanger and which allows a connection to be established between two adjacent plates of two successive tubes. These connections ensure the stability of the structure and allow the sealing to be ensured between an internal space of the heat exchanger and the surrounding environment, that is to say, between the inner space of the tubes and the air. They also allow the cooling fluid to circulate in the exchanger by passing from one tube to the other.
Between the ends thereof, the tubes have a central portion, called a tube body, which guides the cooling fluid from one end to the other.
Since the tubes are in contact with each other only in the region of the ends thereof, there are spaces between the bodies of two adjacent tubes. These spaces are used to circulate the first fluid through the heat exchanger so that heat is exchanged with the second fluid which flows inside the tubes.
The exchanger also comprises an inlet tube which conveys the cooling fluid to the tubes and which is connected to the tubes by means of an inlet cross-member and an outlet tube which discharges the cooling fluid from the tubes and which is connected to them by means of an outlet cross-member.
In order to increase the cooling power of the exchanger to the maximum extent whilst reducing its mass, document FR2929388A1 proposes a thickness of less than 0.3 mm for the plates which form the tubes. A problem arises when the tube(s) is/are subjected to mechanical stresses linked, for example, to the operation of the vehicle. These stresses affect the plates of the exchanger via the cross-members. Since the plates have a thickness of less than 0.3 mm, they become deformed under the action of the stress, which may bring about a breakage between two adjacent plates, thus creating a leakage which allows the cooling fluid to escape.
An object of the invention is to overcome the above-mentioned problem by proposing to improve the resistance to stresses in the region of the connections between two adjacent plates whilst continuing to use plates having a thickness of less than 0.3 mm.
To this end, there is proposed a heat exchanger comprising a multiplicity of stacked plates having a thickness of less than 0.3 mm, each of which is provided with a male dished member which delimits a fluid distribution zone in the exchanger, at least a first plate and a second plate each comprise a peripheral edge which is assembled in a fluid-tight manner in order to form a fluid circulation pipe.
According to the invention, the heat exchanger comprises at least one insert which is provided with a female dished member, the male dished member of the plates being configured to be introduced into the female dished member of the insert in order to ensure fixing between two adjacent pipes or between a side plate and an adjacent pipe.
That is to say, according to the invention, the heat exchanger has at least one insert which is provided with a protruding edge which is configured to extend and surround the male dished member of an adjacent plate in order to increase the stress resistance of the connection between the insert and the plate.
The multiplicity of plates extend over a width between a first side of the exchanger and a second side of the exchanger. The plates located at the sides of the exchanger are thus referred to as “side plates”.
According to an aspect of the invention, the insert is integral with a first or second plate of a pipe.
According to an aspect of the invention, the insert is a component which is fitted to a first or second plate of a pipe or to a side plate.
According to an aspect of the invention, the female dished member of the insert has a tubular section which terminates in an edge which covers the male dished member of the first and/or second plate, the edge extending in continuation of the tubular section. It is intended to be understood in this instance that the edge forms a cylindrical cross-section which is coaxial with the tubular section and which has an equivalent diameter. By covering the male dished member of one of the plates with the female dished member present on the insert, the connection between the plate and the insert is thus reinforced, regardless of the direction of the stresses to which the connection is subjected.
According to an aspect of the invention, the male dished member of the first and/or second plate has a tubular section which terminates in a base which extends in a plane perpendicular to a centre axis of the tubular section. The base is, for example, provided with an opening through which the fluid passes. It is thereby possible to define the path of the second fluid within the exchanger, by selecting a base which may or may not be provided with an opening .
According to an aspect of the invention, the multiplicity of plates comprise a fluid circulation portion which is interposed between two plate ends, the male dished member of the first and second plates being formed at least at one end of the plates.
According to an aspect of the invention, the first and second plates which delimit a pipe or the assembly formed by a plate a pipe and a side plate each comprise at an end both a male dished member and a female dished member. In this manner, the reinforced connection between the plate and the insert is doubled and its strength is thus improved.
According to an aspect of the invention, each end of the plates comprises both a male dished member and a female dished member.
According to an aspect of the invention, the first twenty-five percent of the width from one side of the exchanger is configured so that the male dished member of each plate is introduced into the female dished member of each insert in order to ensure fixing between the plates. It will thus be appreciated that the exchanger is provided in this instance with a plurality of inserts. The plates located in the remaining seventy-five percent of the width thus do not have such inserts. In this manner, reinforcement is provided in particular for the zone of the exchanger that is subjected mainly to the stresses transmitted by the cooling fluid inlet and/or outlet tubes, that is to say, the zone located near the inlet and/or outlet cross-members which are themselves positioned at one of the sides of the exchanger.
According to an aspect of the invention, since the exchanger comprises a first side plate which is located in the region of the first side of the exchanger and a second side plate which is located in the region of the second side of the exchanger, the insert is installed against each of the side plates so that the female dished member of the insert covers the male dished member of the plate adjacent to the first side plate and the plate adjacent to the second side plate. It will be understood in this instance that such an exchanger comprises two inserts, each one being soldered to a side plate.
The first connections between a plate and an insert starting from the sides of the exchanger are thus reinforced. The side plates have, for example, a thickness of 1 mm, greater than the thickness of the other plates in order to increase the strength of the first connection. The insert has in particular a thickness greater than 0.3 mm.
The appended drawings will show clearly how the invention can be implemented. In these figures, identical reference numerals refer to elements which are similar.
In conventional manner and in order to simplify the description of the heat exchanger 1 according to the invention, a Cartesian reference system (x, y, z) is formed and the direction o-x is defined as being the width of the exchanger, o-y the depth thereof, and o-z the height thereof. The directions o-x, o-y and o-z are parallel with the axes o-x, o-y and o-z, respectively. The embodiment described below is an evaporator but of course the invention also covers a condenser, a radiator or any other exchanger which is constituted according to claim 1, regardless of the fluids which pass through it.
As can be seen in
Fluid, called a second fluid, in particular a cooling fluid which circulates in an air conditioning circuit of a motor vehicle when the heat exchanger 1 is an evaporator, a gas cooler or a condenser, can thus pass through the tube 2. This may also be a heat-exchange fluid which circulates in a cooling circuit of a heat or electric engine of a motor vehicle when the heat exchanger 1 is a radiator.
The fluid distribution zones 6, 7 occupy, for example, a minority fraction of the height of the tube 2 at the upper and lower portions thereof, the remainder of the height of the tube 2 being occupied by a body region of smaller thickness. A fluid circulation portion 19 is thus interposed between two fluid distribution zones, that is to say, between two ends of the same plate. In this manner, two adjacent tubes 2 are in contact in the region of their fluid distribution zones, that is to say, in the region of the male dished member 8 present on the adjacent plates which belong to two different tubes 2. A free space 13 located between two body regions of smaller thickness of two adjacent tubes 2 defines a path in the direction o-y for a first fluid, for example, of the air to be cooled. Insertion members (not illustrated) are in particular installed in the free space 13, in order to increase the thermal exchange between the external walls of the tubes 2 and the flow of air.
The metal sheet which forms the plates 3 and 4 is, for example, an alloy of aluminum and has a thickness of less than 0.3 mm, preferably between 0.24 and 0.28 mm and in particular of 0.27 mm. An internal interference member, in the form of a zig-zag (not illustrated) may be arranged between the plates 3 and 4 of the same tube 2 in order to promote the heat exchanges between the cooling fluid and the internal wall of the tube 2.
The tube 2 may have a sealed connection zone 14, which extends over the height thereof, that is to say, in the direction o-z, and which divides the same tube 2 into a first half-tube 2′ and a second half-tube 2″, and which thus allows the tube 2 to define two paths for the cooling fluid. The first half-tube 2′ of a tube 2 is located towards a front face 17 of the exchanger and the second half-tube 2″ of the same tube 2 is located towards a rear face 18 of the exchanger. The sealed connection zone thus extends from the upper distribution zone 6 as far as the lower distribution zone 7, at the mid-width of the tube 2 in the direction o-y. The sealed connection zone may or may not have a passage (not illustrated) in the region of the upper fluid distribution zone 6 or the lower distribution zone 7, in order to allow the fluid to pass from the first half-tube 2′ to the second half-tube 2″ of the same tube 2, that is to say, in the direction o-y.
Furthermore, two plates 15, 16 called side plates are arranged on the sides of the exchanger in the direction o-x and serve in particular to protect the last intermediate members of the exchanger located at each side of the heat exchanger 1. The term first side of the exchanger 1 refers to the side located in the right-hand portion of
In this manner, from one side to the other in the direction o-x and from right to left in
The heat exchanger 1 further comprises a fluid inlet cross-member 11 and a fluid outlet cross-member 12 which are arranged on an outer face of the first side plate 15 in continuation of the upper fluid distribution zone 6 and/or lower fluid distribution zone 7. The cross-members 11 and 12 protrude relative to the first side plate 15 and may in particular have a tubular cross-section whose centre axis is directed in the direction o-x. The cross-members 11 and 12 may have different diameters.
The embodiment described by way of example in
In this manner, the cooling liquid describes a path in the exchanger between the inlet cross-member 11 and outlet cross-member 12 as a function of the presence or absence of the openings 10 located in the region of the fluid distribution zones, between two half-tubes 2′ or two half-tubes 2″ of two adjacent tubes 2 and the presence or absence of passages located in the region of the connection zone 14 which allows the fluid to pass from one half-tube 2′ to the other half-tube 2′ of the same tube 2, that is to say, from one face to the other of the exchanger in the direction o-y.
In this manner, when the inlet tube 20 and/or outlet tube is subjected to stresses F, regardless of the directions thereof, which are transmitted to the exchanger in the region in particular of the reinforced connection between the first side plate 15 and the first plate 3 of the first tube 2a, the risk of breakage of the metal sheet or the soldered connection is reduced. The reliability of the exchanger is increased accordingly .
The planar cross-section 30 comprises two lateral portions, a lower portion and an upper portion which together define the periphery of the insert 5. When the insert 5 is positioned in the exchanger, the depth thereof corresponds to the depth of the plates, that is to say that the distance between the two lateral portions thereof in the direction o-y is equal to the depth of the plates in the direction o-y. In contrast, the insert 5 is less high than the plates, that is to say, the distance between the upper portion thereof and the lower portion thereof is less than the height of the plates in the direction o-z.
The insert 5 may, for example, be provided with a plurality of tongues 35, which are located on the periphery of the insert 5, perpendicularly relative to the planar cross-section 30, and which are capable of being crimped or folded on the first side plate 15 to which the insert 5 is connected, in order to ensure that it is fixed. The tongues 35 in particular allow the preassembly of the insert 5 against the first side plate 15 to be ensured before the soldering operation. The insert comprises, for example, four tongues 35, two of which are located on the upper portion and one on each of the lateral portions thereof.
At the opposite side of the planar cross-section 30, that is to say, at the right-hand side of the figure, there are located two female dished members 9 which are intended to cover two male dished members 8 of the first plate 3, adjacent to the first side plate 15 to which the insert 5 is fitted. The male dished members 8 and female dished members 9 therefore have a complementary shape which allows one (male 4) to be fitted in the other (female 9). Although not illustrated, the insert 5 may also be provided with a female dished member 9 and a male dished member 4 if the first plate 3 and second plate 4 also have a corresponding male dished member 8 and female dished member 9.
According to a variant of the invention which is not illustrated, the insert 5 is integral with a plate and may be integral with a first plate 3, a second plate 4, a first side plate 15 and/or a second side plate 16. In this instance, it is constituted by the same material as the plate from which it originates, that is to say that it is produced in an integral manner with the plate, forming with it a single unit of material. Such a configuration of the insert 5 becomes evident on the plate on which it is located in particular as a result of the presence of a shoulder, in the region of which the insert 5 begins, that is to say, close to the end of the plate on which the insert 5 is located. If the insert 5 is integral with a plate, it has the same shape as that of the insert 5 which is fitted to the plate as described above.
This shape of the insert 5, whether it is fitted to or integral with a plate, advantageously allows it to be placed between two adjacent plates of the exchanger, regardless of their position amongst the multiplicity of plates.
In this manner, according to another embodiment of the exchanger, two adjacent tubes 2, regardless of their position in the exchanger 1, comprise a first plate 3 of one of the tubes 2 which is assembled with a second plate 4 of another of the tubes via an insert 5. Consequently, one of the first and second plates 3, 4 comprises a connection insert 5 so that the male or female dished member 8 or 9 of a tube is configured to be introduced in or cover the female or male dished member 9 or 8 of a tube 2 which is directly adjacent thereto, respectively.
According to a first production variant, each of the connections between the tubes 2 comprises an insert 5.
According to a second production variant, some of the connections between the plates comprise an insert 5, for example, some connections located in the region of the first twenty-five percent of the width of the exchanger 1, starting from the first side of the exchanger 1, or only between the first and second side plates 15, 16 and the plates 3, 4 thereof which are directly adjacent. Depending on the degree of stress resistance which it is desirable to confer on the exchanger 1, one or other of these production variants is selected.
Still with the objective of reinforcing the structure, side plates 15, 16 having a thickness which is approximately 1 mm are advantageously but not exclusively selected. In the same manner, inserts 5 are selected having a thickness greater than 0.3 mm, but it may be advantageous to select an insert 5 having a thickness which is identical to the thickness of the first and second plates 3, 4 which constitute a tube.
This male dished member 8 of the first plate 3 or the second plate 4 also has a tubular section 31 which is configured so that it can be introduced in the tubular section 21 of the insert 5 but which itself terminates in a base 33 which extends in a plane perpendicular to a centre axis of the tubular section 21, that is to say, in the direction o-x. The base 33 is, for example, provided with an opening 10 through which the fluid passes. It is via these tubular sections 21 and 31 that the fluid will circulate between two adjacent tubes 2 inside the exchanger 1.
According to another embodiment of the exchanger 1, each tube 2 is formed by a first half-tube 2′ and a second half-tube 2″ which are separated from each other by the sealed cross-section. Each plate must be provided with two dished members which delimit the fluid distribution zone 6, 7 in the exchanger 1.
As illustrated in
The heat exchangers according to the invention are used in particular in heating, ventilation and/or air conditioning installations of motor vehicles. They may also be engine cooling radiators, passenger space heating radiators, condensers, gas coolers or evaporators of the air conditioning circuit, supercharger and oil exchanger air coolers.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1100872 | Mar 2011 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2012/052877 | 2/20/2012 | WO | 00 | 1/31/2014 |
