Plate heat exchanger comprising mixing device

Abstract

The invention relates to a heat exchanger (100) comprising a plate bundle (50) forming a plurality of flow channels (51) for a coolant (FR), and a coolant inlet manifold (48) supplying the flow channels (51), said inlet manifold (48, 11) comprising openings (541, 561) in the plates (52, 54, 56) of the plate bundle (50), said openings at least partially delimiting a cylindrical region (480) transverse to the plate bundle (50), said heat exchanger (100) being characterized in that: said openings (541, 561) are formed in the plates (52, 54, 56) of the plate bundle (50); and at least one mixing device (546, 566) for mixing the coolant (FR), the mixing device extending in the inlet manifold (48) and being integral with at least one of the plates (54, 56) of the plate bundle (50).

Description

Technical Field

[0001] The present invention relates to the field of thermodynamics and more particularly to a heat exchanger intended in particular for cooling components of a vehicle. Background Art

[0002] In electric or hybrid vehicles, the vehicle's battery, electric motor, and power electronics are typically cooled by a heat transfer fluid (such as water) circulated through these components in a heat transfer fluid circuit. The heat transfer fluid itself is cooled by a heat exchanger that receives the heat transfer fluid and a refrigerant. The refrigerant undergoes a thermodynamic cycle in a separate refrigerant circuit using, for example, a compressor, a condenser, an internal heat exchanger, and an expansion element.

[0003] During rapid charging of the battery of an electric or hybrid vehicle, due to the high current, the heat power to be dissipated to cool the battery is significant, for example, approximately 10,000 W. Similarly, when the electric or hybrid vehicle is traveling at high speed, the heat power to be dissipated in the electric motor, power electronics, and battery is significant, and therefore requires a heat exchanger that is dimensioned accordingly, referred to as a "high-performance" heat exchanger.

[0004] Since a heat exchanger is formed by a set of stacked and brazed plates defining channels for circulating a refrigerant or heat transfer liquid, the number of plates in a heat exchanger of an electric or hybrid vehicle is increasingly high when it has to dissipate high thermal powers.

[0005] However, when an electric or hybrid vehicle is used in a less energy-intensive manner, such as during slow charging of the electric vehicle's battery or when the electric vehicle is traveling at low speed, the thermal power to be dissipated from the battery is lower, for example, approximately 4,000 watts. However, the efficiency of "high-performance" heat exchangers is suboptimal at medium or low loads, as the number of plates and channel dimensions of such heat exchangers are optimized for high-load use. Consequently, at medium or low loads, the distribution of the refrigerant's liquid and gas phases in the heat exchanger is uneven and inefficient.

[0006] Therefore, there is a need for a high-performance heat exchanger, in particular for electric or hybrid vehicles, which has improved thermal performance and efficiency, in particular at low and medium loads, so that components of the vehicle can be cooled. The vehicle components to be cooled preferably include the battery, the electric motor and the power electronics, but also the interior of the vehicle. Summary of the Invention

[0007] The present invention at least partially overcomes the disadvantages of the prior art by providing a plate pack heat exchanger in which the distribution of the refrigerant in the plate pack is improved.

[0008] To this end, the present invention proposes a heat exchanger comprising a plate package forming a plurality of channels for circulating a refrigerant and a refrigerant inlet header supplying the circulation channels, the inlet header comprising openings in the plates of the plate package, the openings at least partially defining a cylindrical area in the inlet header, the heat exchanger comprising at least one mixing device for mixing the refrigerant, the mixing device extending in the inlet header and being formed integrally with at least one plate of the plate package.

[0009] With the present invention, the refrigerant, which was previously a separated two-phase flow before entering the heat exchanger, flows in the inlet header as a dispersed two-phase flow due to a mixing device. The refrigerant consists of a gas phase, a liquid phase, and a small percentage of oil. Before entering the heat exchanger, it flows in pockets or plugs. The pockets or plugs of refrigerant are atomized by contact with the mixing device, which forms a singular point in the inlet header. This atomization is caused by the decompression phenomenon each time the refrigerant passes through an opening in the plate of the plate pack, effectively mixing the liquid and gas phases of the refrigerant.

[0010] Furthermore, since the mixing device is formed integrally with at least one plate of the plate pack, the heat exchanger according to the invention uses resources economically and allows rapid production, since the mixing device is assembled simultaneously with the heat exchanger obtained by brazing the plate pack.

[0011] According to an advantageous feature of the heat exchanger according to the invention, the mixing device comprises at least one diverting device which directs the refrigerant towards the upper part of the inlet header.

[0012] When the circulation channels are U-shaped, this upper portion of the inlet header is located opposite a portion of the heat exchanger's circulation channels, including a bend in the heat exchanger's circulation channels. Alternatively, when the circulation channels provide circulation in one or three paths, this upper portion of the inlet header is located opposite the outlet of the circulation channels. In other words, this upper portion of the inlet header, which in the prior art receives less refrigerant, receives more refrigerant through the mixing device. In particular, when the mixing device takes the form of a coil, the coil radially deflects the peripheral portion of the refrigerant flow reaching the inlet header over the entire angular range of the inlet header. As a result, the refrigerant flows more easily in the outer peripheral portions of the circulation channels, which are adjacent to the lateral walls of the heat exchanger formed by the edges of the plate pack. Consequently, the refrigerant flow is better distributed within each circulation channel, which improves the heat transfer coefficient of the heat exchanger and reduces pressure variations within each circulation channel.

[0013] Preferably, the mixing device forms part of the edge of the plate opening, protruding into the cylindrical region and extending radially toward the central axis of the cylindrical region. In this embodiment, the mixing device contacts the refrigerant flow in the inlet header to create a singularity that enables a dispersed two-phase flow. Furthermore, in this embodiment, the mixing device is formed, for example, by stamping and / or semi-shearing the edge of the opening. Consequently, compared to the prior art, the mixing device can be easily manufactured without excessive waste.

[0014] Preferably, in this embodiment, the mixing device comprises a foot extending over the angled portion of the opening and connected to the plate, and a head extending in continuation of the foot and at a distance from the portion of the edge of the opening that is angularly flush with the head. The head thus projects relative to the remainder of the opening and is positioned facing the inlet opening of the inlet header. This projecting head makes it possible to radially divert a portion of the refrigerant flow toward the flow channel, in particular toward the upper portion of the inlet header.

[0015] For example, the mixing device extends over the entire edge of the opening and forms a helical coil, the axis of which coincides with the central axis of the cylindrical region, a first angled portion of the helical coil forming a foot, and a second angled portion of the helical coil forming a head. This feature imparts a swirl effect to the flow diverted by the mixing device, which facilitates atomization of the refrigerant exiting the inlet header toward the flow-through channel.

[0016] According to an advantageous feature of the heat exchanger according to the invention, the mixing device comprises at least a first mixing device and a second mixing device, the first mixing device being formed on the edge of an opening of a first plate adjacent to the second plate, and the second mixing device being formed on the edge of an opening of the second plate, the first and second mixing devices protruding between the first and second plates. This arrangement angularly increases the area available for atomizing the refrigerant exiting the inlet header toward the flow-through channels by increasing the number of deflection elements between two adjacent plates of the plate pack.

[0017] In one embodiment of the present invention, the first and second mixing devices converge and together form a spiral section whose axis coincides with the central axis of the cylindrical region. Specifically, the coil of the first plate includes an angled end surface positioned orthogonally to the main extension plane of the end face, in the same position as the angled end surface of the coil of the second plate. These surfaces are thus positioned against each other and brazed together during brazing of the heat exchanger to form the spiral section. This arrangement of the mixing devices allows for uniform distribution of the refrigerant throughout the plate pack, limiting pressure drop.

[0018] Preferably, in this embodiment, the plate pack comprises alternating plates identical to the first plate and plates identical to the second plate, the first and second mixing means of these alternating plates forming a spiral extending over the length of the refrigerant inlet header and facing the flow channels. The refrigerant is thus evenly distributed throughout the plate pack.

[0019] According to an advantageous feature of the heat exchanger according to the present invention, the inlet header includes a cylindrical passage transverse to the flow channels, the cylindrical passage being at least partially defined by the mixing device. This cylindrical passage allows the refrigerant to be delivered to the distribution channels furthest from the inlet opening of the inlet header. Preferably, the diameter of the cylindrical passage is between 4 and 8 mm, and the plate pack comprises 30 to 70 plates. This smaller diameter than in the prior art accelerates the refrigerant and allows it to form jets, improving the distribution of the refrigerant throughout the inlet header formed by the large number of plates. Thus, the present invention provides improved refrigerant distribution under low, medium, or high loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other characteristics and advantages of the invention will become more apparent from the following description and from a number of exemplary embodiments provided by way of non-limiting indication with reference to the accompanying schematic drawings, in which:

[0021] Figure 1 is a perspective view of a cross section of a heat exchanger according to the invention showing the inlet header of said heat exchanger in a first embodiment of the invention,

[0022] Figure 2 yes Figure 1 An enlarged view of a portion of the inlet header in which the mixing section extends,

[0023] Figure 3 yes Figure 1 A perspective view of two different plates of a plate pack of a heat exchanger,

[0024] Figure 4 yes Figure 3 An enlarged view of a portion of one of the plates, comprising a mixing device,

[0025] Figure 5 yes Figure 3 An enlarged view of a portion of another plate in FIG. 1 , which includes a mixing device,

[0026] Figure 6 is a perspective view of a cross section of a heat exchanger according to the invention showing the inlet header of said heat exchanger in a second embodiment of the invention,

[0027] Figure 7 Schematically shows the distribution of the refrigerant on the plates of the plate pack without a mixing device, and

[0028] Figure 8 The schematic diagram shows the refrigerant Figure 6 The distribution on the plates of the heat exchanger comprises mixing means. DETAILED DESCRIPTION

[0029] according to Figure 1 In the illustrated first embodiment of the invention, a heat exchanger 100 according to the invention comprises a plate package 50 forming alternating flow channels 51, through which a refrigerant FR circulates, and flow channels 53, through which a heat transfer liquid, such as glycol water, circulates. In a known manner, the refrigerant FR is, for example, a hydrofluoroolefin (HFO) mixed with a small percentage of oil, the oil being less than 5% or even less than 3%.

[0030] The plate package 50 is delimited at one end thereof, which includes the refrigerant inlet opening 46 of the heat exchanger 100 , by an end face 42 and at the other end thereof by a closing plate 44 of the plate package 50 .

[0031] The inlet opening 46 extends into the inlet header 48 of the heat exchanger 100 and surrounds the openings 541, 561 formed in each plate of the plate pack 50 (at Figure 2 These openings extend from the center axis X of the plate group 50 and define a cylindrical region 480 passing through the center axis X of the plate group 50. The inlet header 48 serves as a refrigerant flow channel 51.

[0032] like Figure 2 As shown, plate assembly 50 includes two different types of plates, corresponding to plates 54 that are identical to each other, and plates 56 that are identical to each other. Plate assembly 50 is formed by alternating plates 54 and 56 that are brazed to each other in pairs and in contact with each other on a planar portion of inlet header 48 (i.e., around plate openings 541 and 561). Thus, each pair of plates 54 and 56 brazed to each other forms a partition between two flow channels 51 at the inlet header 48 of heat exchanger 100. The pair of plates 54 and 56 forming this partition separates outside of the inlet header 48 to form a heat transfer liquid flow channel 53 that is sealed from the refrigerant flow channel 51.

[0033] Each plate 54 comprises a device 546 for mixing the refrigerant FR entering through an opening 541 of the plate 54. This mixing device 546 is formed integrally with the plate 54 and is more particularly obtained by punching and half-shearing said opening 541. It forms the edge of this opening 541 and projects into the space allowing the refrigerant to enter the refrigerant circulation channel 51, this space being contained between the plate and a plate 56 facing the plate 54 but positioned at a distance therefrom in the inlet header 48.

[0034] The plate 56 also comprises means 566 for mixing the refrigerant FR obtained by punching and half-shearing the edge of the opening 561 of the plate 56 and projecting into the space allowing the refrigerant to enter the refrigerant circulation channel 51 , this space being delimited by the plates 54 and 56 .

[0035] Each mixing device 546, 566 of the plate 54 or 56 is in the form of a helical coil whose axis is the central axis X of the cylindrical area 480. The first angular portion 5662 of the helical coil 566 (at Figure 4 The edge of the opening 561 forming the plate 56 extends in the direction of the central axis X in the inlet header 48 while remaining attached to the plate 56, i.e., no radial passage for the refrigerant is provided between this first angular portion 5662 and the rest of the plate 56. The second angular portion 5664 of the spiral coil 566 (in the middle) continues from the first angular portion 5662. Figure 4 The edge of the opening 561 forming the plate 56 (marked in the middle) extends in the direction of the central axis X in the inlet header 48 while being separated from the plate 56, that is, the refrigerant FR can pass radially between the second angular portion 5664 and the rest of the plate 56.

[0036] Similarly, the first angled portion 5462 of the helical coil 546 (at Figure 5 The edge of the opening 541 of the plate 54 is formed by the first angled portion 5462 (marked in the middle) and extends in the direction of the central axis X in the inlet header 48 while remaining attached to the plate 54, i.e., no radial passage for the refrigerant is provided between this first angled portion 5462 and the rest of the plate 54. The second angled portion 5464 of the spiral coil 546 (marked in the middle) is continuous with the first angled portion 5462. Figure 5 The edge of the opening 541 of the plate 54 formed by the second angular portion 5464 extends in the direction of the central axis X in the inlet header 48 while being separated from the plate 54, that is, the refrigerant FR can pass radially between the second angular portion 5464 and the rest of the plate 54.

[0037] At its angled end separated from the plate 54, each helical coil 546 of the plate 54 meets the angled end of a helical coil 566 of the plate 56 separated from the plate 56. The two joined coils 546 and 566 are brazed to each other at these angled ends, more specifically at the respective angled end surfaces 5465, 5665 (at Figure 4 and Figure 5 The two members are brazed to each other on the upper surface (marked in the middle) to form a spiral portion.

[0038] The helical coil 546 of the plate 54 thus imparts a rotational motion to a portion of the refrigerant FR arriving against this helical coil 546. The second angled portion 5464 of this helical coil 546 makes it possible to divert a portion of the refrigerant FR radially and angularly, in particular towards the upper portion 482 of the inlet header 48 (at Figure 1 The upper portion 482 is located in the opposite direction to the curved end portion of the refrigerant flow channel 51, as shown below. Figure 3 The helical coil 566 also receives a portion of the refrigerant FR arriving against it or driven by the aforementioned rotational movement and also makes it possible to divert a portion of the refrigerant FR radially and angularly around the central axis X.

[0039] Since each plate 54 , 56 is provided with a helical coil 546 , 566 , these coils 546 , 566 of the assembly of plates of the plate pack 50 form a helix extending along the central axis X in the inlet header 48 .

[0040] Figure 3 Plate 54 and plate 56 are shown as a whole and make it easier to understand the structure of the stack of plates forming plate pack 50. Figure 3 In the embodiment, plate 54 has a face 540 intended to be brazed to a face 560 of plate 56 (in Figure 2 (marked in the middle), located Figure 3 The opposite side of the face 562 of the plate 56 is shown. In other words, the plate 56 is stacked and brazed on top of the plate 54 and in contact with the plate 54. Positioned like this, the pair of plates 54, 56 form a partition between the two refrigerant flow channels 51.

[0041] Plate 56 includes spoilers 569 on main portion 57 that protrude from the planar surface of face 560. These spoilers 569 extend orthogonally relative to this planar surface to the same level as planar portion 59 of plate 56 around opening 561 of inlet header 48. In other words, main portion 57 is raised relative to planar portion 59 on face 562 around opening 561, including helical coil 566. Ridge 5622 defines the protrusion of main portion 57 from planar portion 59. Helical coil 566 extends orthogonally from this planar portion 59 to the same level as the planar surface of main portion 57 located on the same side as face 562. When plate 56 is pressed against plate 54, planar portion 59 around opening 561 contacts corresponding planar portion 58 of plate 54 around opening 541 of inlet header 48. Helical coils 561 and 541 of respective plates 56 and 54 protrude in contact with each other on both sides of these planar portions 58 and 59. The refrigerant FR is therefore unable to flow between the plates 54 , 56 .

[0042] Similarly, the periphery of opening 543 of plate 54, which forms part of the outlet header of heat exchanger 100, is sealingly brazed to the periphery of opening 563 of plate 56, which forms part of the outlet header. Refrigerant FR is therefore unable to pass from the outlet header toward heat transfer fluid circulation channel 53 located between plates 54 and 56. This contact between the peripheries of openings 543 and 563 is permitted because refrigerant outlet opening 563 is located on a portion of plate 56 at the same level as the planar portion 59 including opening 561 relative to the main portion 57 of plate 56, while opening 543 is located in the continuation of the main portion 61 of plate 54 without turning orthogonally thereto.

[0043] The plate 54 also comprises a spoiler 549 on the main portion 61 which extends from the face 542 of the plate 54 (at the side opposite to the face 540 of the plate 54). Figure 2 The spoilers 549 extend orthogonally to the plane surface at the same distance as the spiral coils 546 of the plate 54, which also protrude on the same side as the face 542. Of course, other types of disrupting elements can be provided instead of or in addition to these spoilers 549.

[0044] Unlike plate 56, the planar portion 58 of plate 54 surrounding the opening 541 of the inlet manifold 48 lies in the same plane as the main portion 61, which lacks its protruding elements (particularly the baffle 549). However, this main portion 61 is raised on face 540 relative to the planar portion of plate 54 containing the opening 545 of the heat transfer liquid inlet manifold for heat exchanger 100, and relative to the planar portion of plate 54 containing the opening 547 of the heat transfer liquid outlet manifold for heat exchanger 100. Plate 56 includes an opening 565 of the heat transfer liquid inlet manifold facing opening 545, and an opening 567 of the heat transfer liquid outlet manifold facing opening 547. These openings 565 and 567 of plate 56 are located in continuation of the main portion 57 of plate 56, rather than turning orthogonally thereto. In other words, the heat transfer liquid inlets 565 and 545 are located at a distance from each other, and the heat transfer liquid outlets 567 and 547 are located at a distance from each other. When the plate 56 is brazed to the plate 54, the heat-transfer liquid reaching the heat-transfer liquid inlet header can thus circulate in the circulation channels 53 between the plates 54 and 56, and between the baffles 569 of the plate 56, which provide a distance between the plane surface of the main portion 57 of the plate 56 situated on the same side as the face 560 and the plane surface of the main portion 61 of the plate 54 situated on the same side as the face 540. The heat-transfer liquid inlet opening 565 and the heat-transfer liquid outlet opening 567 are separated by a groove 568 arranged on the face 562 of the plate 56, the groove 568 extending from the middle of one edge of the plate 56 towards the opposite edge but not reaching the opposite edge. Thus, the heat transfer liquid arriving through the heat transfer liquid inlet opening 545 of the plate 54 is forced to bypass the groove 568 before exiting through the heat transfer liquid outlet opening 547 of the plate 54, which causes the heat transfer liquid to travel along the entire length of the plate 54. The flow channel 53 is U-shaped, with the bend of the U-shape being located at the longitudinal end of the plate 56 opposite the heat transfer liquid openings 565, 567 of the plate 56. The refrigerant inlet header 48 and the refrigerant outlet header are located on the other longitudinal end of the plate 56.

[0045] In contrast, when plate 54 is positioned on plate 56, that is, when face 542 of plate 54 is brazed to face 562 of plate 56, flat portion 58 of plate 54 surrounding opening 541 of inlet header 48 is spaced apart from flat portion 59 of plate 56 surrounding opening 561 of inlet header 48, and coils 546 and 561 of the two plates 54 and 56 meet at their angled end surfaces 5465 and 5665. Refrigerant FR arriving through opening 541 can thus circulate between plates 54 and 56 in the circulation flow path 51 formed between the plates 54 and 56. In this case, refrigerant FR circulates between baffles 549 of plate 54, which provide a distance between the flat surface of main portion 61 of plate 54, located on the same side as face 542, and the flat surface of main portion 57 of plate 56, located on the same side as face 562.

[0046] A groove 548 disposed on the face 540 of the plate 54 separates the opening 541 of the refrigerant inlet header 48 from the opening 543 of the refrigerant outlet header. The groove 548 extends from the middle of one edge of the plate 54 toward, but does not reach, the opposite edge. Consequently, refrigerant arriving through the refrigerant inlet 541 is forced to bypass the groove 548 before exiting through the refrigerant outlet 543 of the plate 54, causing the refrigerant to travel along the entire length of the plate 54. The flow channel 51 is U-shaped, with the bend of the U located at the longitudinal end of the plate 54 opposite the refrigerant openings 541 and 543, which is near the edge of the plate 54 from which the groove 548 extends. Heat transfer liquid openings 545 and 547 of the plate 54 are located at opposite longitudinal ends of the plate 54.

[0047] The dimension of the baffle 549 in a direction perpendicular to the end face 42 is the same as the horizontal change in that perpendicular direction between the portion of the plate 54 including the heat-transfer liquid openings 545, 547 and the planar surface of the main portion 61 of the plate 54 located on the same side as the face 542. As a result, the perimeters of the heat-transfer liquid openings 545, 547 of the plate 54 are in complete contact with the corresponding perimeters of the corresponding heat-transfer liquid openings 565, 567 of the plate 56, which are located in continuation of the main portion 57 of the plate 56 without turning perpendicular thereto. As a result, the heat-transfer liquid entering through the opening 545 of the plate 54 cannot enter the refrigerant circulation channel 51, and the heat-transfer liquid exiting through the opening 547 of the plate 54 likewise cannot enter the circulation channel 51.

[0048] It should be noted that the dimensions of the coils orthogonal to the planar portions 58 and 59 may vary slightly from those described herein to allow for the mixing devices 546, 566 to function even if they do not precisely meet at their respective angled end surfaces 5465 and 5665.

[0049] Back to Figure 1 The refrigerant FR reaching the inlet orifice 46 from the refrigerant connection block 40 brazed to the end face 42 of the heat exchanger 100 is composed of a small percentage of oil, and a refrigerant compound of 30% gas phase and 70% liquid phase. The refrigerant FR entering the inlet orifice 46 reaches the inlet header 48 through an opening formed in a first plate 52 brazed to the first plate 54 of the plate pack 50 near the end face 42 of the heat exchanger 100. This plate 52 allows the formation of a first flow channel 53 between it and the first plate 54, without a spiral coil protruding from the plate 52 toward the end face 42. In other words, the plate 52 is structurally identical to the plate 56, except that it does not include a mixing device.

[0050] A portion of the refrigerant FR reaching the inlet header 48 passes through the opening in the plate 52 and the openings 541 and 561 formed in the plates 54, 56 of the plate pack 50 to reach the closing plate 44. The portion of the refrigerant FR that directly passes through the inlet header 48 is formed by the inner contours 544, 564 (at the inner contours 544, 564) of the respective helical coils 546 and 566 of each respective plate 54, 56. Figure 4 and Figure 5 The cylindrical channel 60 (marked in Figure 2 (marked in Chinese) in circulation.

[0051] The diameter of the cylindrical channel 60 is approximately 5 mm, and in the first embodiment of the invention, the plate pack 50 includes 60 plates. As a variant, the diameter of the cylindrical channel has a different value between 4 and 8 mm, and the plate pack includes 30 to 70 plates. This diameter is smaller than the average diameter of the opening of the inlet header of the prior art, so as to allow the refrigerant to easily pass from the end face 42 of the heat exchanger 100 to the opposite end of the inlet header 48.

[0052] The other portion of the refrigerant FR is turned from a direction parallel to the central axis X and reaches each of the refrigerant circulation channels 51. This turning of the portions of the flow of the refrigerant FR is facilitated by the respective helical coils 546 and 566 at the inlet of each circulation channel 51.

[0053] according to Figure 6 and Figure 8In the second embodiment of the invention shown, a heat exchanger 10 according to the invention comprises a plate package 20 delimited by an end face 14 and a closing plate 16. A connecting block 12 is rigidly connected to the end face 14 and allows the refrigerant FR to enter an inlet opening 18 arranged in the end face 14. This inlet opening 18 projects into the inlet header 11 of the heat exchanger 10. The plate package 20 comprises two alternating types of plates, namely plates 24 and 26, which form alternating channels 23 for the circulation of the heat transfer liquid and channels 21 for the circulation of the refrigerant. This arrangement of the heat exchanger 10 is structurally identical to that of the heat exchanger 100, with only the mixing devices 31 formed in the openings 30 of the plates 24, 26 having a different structure from the mixing devices 546, 466 of the first embodiment of the invention.

[0054] In particular, the inlet header 11 comprises a cylindrical area 110 at least partially delimited by the opening 30, and an upper portion 112 in the direction opposite the bends of the flow channels 21, 23, these bends themselves being located at the longitudinal ends of the plates 24, 26. Moreover, similar to the plate 52 of the first embodiment of the invention, the inlet plate 22, which does not include the mixing device 31, is located against the end face 14.

[0055] The mixing device 31 of the plate 24 protrudes into the space contained between the plate 24 and the plate 26, which allows the refrigerant FR to enter the refrigerant circulation channels 21. The mixing device 31 of the plate 26 protrudes into the same space. Therefore, the mixing devices 31 of the plates 24 and 26 face each other in each circulation channel 21.

[0056] Each mixing device 31 comprises a foot 33 rigidly connected at one end to the rest of the plate 24, 26 to which it belongs and connected at the other end to a head 35 of the mixing device projecting relative to the rest of the plate 24, 26. The head 35 of the mixing device 31 makes it possible to divert the refrigerant FR arriving through the inlet orifice 18 towards the circulation channels 21 or towards the upper portion 112 of the header 11, as indicated by the arrow orthogonal to the direction given by the axis X, which is the central axis of the cylindrical area 110.

[0057] The head 35 leaves a cylindrical channel 15 in the cylindrical area 110, which allows the refrigerant FR to pass unhindered through the inlet header 11 to the closing plate 16. The diameter of this cylindrical channel 15 is, for example, 5 mm, and the number of plates 24, 26 is approximately 60.

[0058] With such Figure 7 Compared to the plate 2 shown without the mixing device, the distribution of the refrigerant FR on the plate 24 (or 26) is improved, as shown in FIG. Figure 8 As shown. Figure 7In the diagram, refrigerant FR enters the refrigerant circulation channel defined by plate 2 through opening 4 in plate 2, bypasses groove 6 separating opening 4 from refrigerant outlet opening 8, and then exits plate 2 through outlet opening 8. The arrows formed by dashed and dotted lines illustrate the flow of refrigerant FR on plate 2, with the thicker the arrow, the greater the flow velocity. It should be noted that the refrigerant flow has a very low velocity around the periphery of plate 2 and near groove 6. The refrigerant is therefore unevenly distributed in the circulation channel defined by plate 2.

[0059] exist Figure 8 In the illustrated plate 24, the refrigerant FR enters the refrigerant circulation channel 21 defined by the plate 24 through an opening 30 in the plate 24, bypasses a groove 34 separating the opening 30 from a refrigerant outlet opening 32, and then leaves the plate 24 through the outlet opening 32. The arrows formed by the dashed and dotted lines also illustrate the flow of the refrigerant FR on the plate 24, and the thicker the arrow, the greater the flow rate of the flow.

[0060] It will be noted that the header 35 makes it possible to divert a portion of the flow of the refrigerant FR towards the upper portion 112 of the inlet header 11, distributing this diversion evenly and angularly around the opening 30 of the plate 24. As a result, the flow of the refrigerant FR at the periphery of the plate 24 has a higher velocity than that of the plate 2, and the flow of the refrigerant FR near the groove 34 has a higher velocity than that of the plate 2. The refrigerant FR is thus more evenly distributed in the flow channels 21 delimited by the plate 24 than in the flow channels delimited by the plate 2. Consequently, the heat transfer of the heat exchanger 10 is superior to that of the heat exchangers of the prior art.

[0061] Of course, the present invention is not limited to the embodiments that have just been described, and many modifications may be made to these embodiments without departing from the scope of the present invention. In particular, the features of different embodiments or variants may be combined to implement the present invention, as long as these embodiments or variants are not mutually incompatible.

Claims

1. A heat exchanger (100, 10) comprising a plate group (50, 20) forming a plurality of channels (51, 21) for circulating a refrigerant (FR), and a refrigerant inlet header (48, 11) supplying the circulation channels (51, 21), the inlet header (48, 11) comprising openings (541, 561, 30) in the plates (52, 54, 56, 22, 24, 26) of the plate group (50, 20), the openings at least partially defining a cylindrical area (480, 110) in the inlet header (48, 11), the heat exchanger (100, 10) comprising at least one mixing device (546, 566, 31) for mixing the refrigerant (FR), the mixing device extending in the inlet header (48, 11) and being formed integrally with at least one plate (54, 56, 24, 26) of the plate group (50, 20).

2. The heat exchanger (100, 10) according to claim 1, wherein: The mixing device (546, 566, 31) comprises at least one diverting device (5464, 5664, 35) for conveying the refrigerant (FR) towards the upper part of the inlet header (48, 11).

3. The heat exchanger (100, 10) according to claim 1 or 2, wherein: The mixing device (546, 566, 31) forms part of the edge (544, 564) of the opening of the plate (54, 56, 24), the mixing device (546, 566, 31) protruding into the cylindrical area (480, 110) and extending radially towards the central axis (X) of the cylindrical area (480, 110).

4. The heat exchanger (100, 10) according to claim 3, wherein: The mixing device (546, 566, 31) is obtained by punching and / or half-shearing the edge (544, 564) of the opening (541, 561, 30).

5. The heat exchanger (100, 10) according to claim 3 or 4, wherein: The mixing device (546, 566, 31) comprises a foot (5462, 5662, 33) extending over an angled portion of the opening (541, 561, 30) and connected to the plate (54, 56, 24), and a head (5464, 5664, 35) continuing the foot and extending at a distance from a portion of the edge of the opening positioned flush at an angle with the head (5464, 5664, 35).

6. The heat exchanger (100) according to claim 5, wherein The mixing device (546, 566) extends over the entire edge (544, 564) of the opening (541, 561) and forms a helical coil, the axis of which coincides with the central axis (X) of the cylindrical area (480), a first angled portion of the helical coil forming the foot (5462, 5662) and a second angled portion of the helical coil forming the head (5464, 5664).

7. The heat exchanger (100) according to any one of claims 1 to 6, wherein: The mixing device comprises at least a first mixing device (546) and a second mixing device (566), wherein the first mixing device (546) is formed on an edge (544) of an opening (541) of a first plate (54) adjacent to a second plate (56), and the second mixing device (566) is formed on an edge (564) of an opening (561) of the second plate (56), and the first mixing device (546) and the second mixing device (566) protrude between the first plate (54) and the second plate (56).

8. The heat exchanger (100) according to claim 7, wherein: The first mixing device (546) and the second mixing device (566) meet and together form a spiral portion, the axis of which coincides with the central axis (X) of the cylindrical region (480).

9. The heat exchanger (100) according to claim 8, wherein The plate set (50) comprises alternating plates identical to the first plate (54) and plates identical to the second plate (56), the first and second mixing devices (546, 566) of these alternating plates (54, 56) forming a spiral extending over the length of the refrigerant inlet header (48) facing the flow channel (51).

10. The heat exchanger (100, 10) according to any one of claims 1 to 9, wherein: The inlet header (48, 11) includes a cylindrical passage (60, 15) transverse to the flow channel (51, 21), the cylindrical passage being at least partially defined by the mixing device.

11. The heat exchanger (100, 10) according to claim 10, wherein: The diameter of the cylindrical channel (60, 15) is between 4 mm and 8 mm, and the plate set (50, 20) includes 30 to 70 plates.

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