Heat Exchanger Tube, Heat Exchanger Comprising Such Tubes And Method For Producing One Such Tube

Abstract

Heat exchanger tube (100), in particular the condenser of a motor vehicle air conditioning system, is disclosed. The tube comprises a folded wall (105) defining a housing (115), and an internal separator (130), inserted into said housing, said internal separator defining a plurality of fluid circulation channels (136), said wall (105) having large surfaces connected by radii. The tube (100) is configured so that the clearance between the wall (105) and the internal separator (130) is filled along at least one radius (110).

Claims

1-6. (canceled)

7. A method of producing a heat exchanger tube, said tube comprising a bent wall defining a housing and an internal separator inserted into said housing, said internal separator defining a plurality of fluid circulation channels and said wall having large surfaces of length L connected by radii of height H, said method comprising the steps of: inserting an internal separator in the housing of the tube with a clearance; and compressing the tube in the direction of its height, said compression compressing the tube from a height H1 to a height H2 with H2<H1 and from a length L1 to a length L2 with L1<L2, the tube being configured after compression so that the clearance between the wall and the internal separator is at least partially filled.

8. The method as claimed in claim 7, including a preliminary step wherein the wall of the tube is produced by bending a sheet of material, said wall having, after bending, a substantially closed section in which the internal separator is inserted.

9. The method as claimed in claim 7, wherein the compression is exerted in a direction substantially orthogonal to the plane faces of the tube.

10. A method of producing a heat exchanger tube, said tube comprising a bent wall defining a housing and an internal separator inserted into said housing, said internal separator defining a plurality of fluid circulation channels and said wall having large surfaces of length L connected by radii of height H, said method comprising the steps of: inserting an internal separator in the housing of the tube with a clearance; and compressing the tube in the direction of its height, said compression compressing the tube from a height H1 to a height H2 with H2<H1 and from a length L1 to a length L2 with L1 <L2, the tube being configured after compression so that the clearance between the wall and the internal separator is at least partially filled, wherein the compression step is such that the tube and its components, wall or internal separator, have the features as claimed in claim 1.

11. The method as claimed in claim 8, wherein the compression is exerted in a direction substantially orthogonal to the plane faces of the tube.

Description

[0031] The appended figures explain how the invention may be reduced to practice. In these figures, identical references design similar elements.

[0032] FIG. 1A represents a tube bent into the shape of a B before compression in accordance with one embodiment of the invention and including an internal separator inserted between the walls of the tube.

[0033] FIG. 1B represents the tube from FIG. 1A after compression.

[0034] As shown in FIGS. 1A and 1B and in accordance with the invention, a heat exchanger tube 100, notably of an air conditioning condenser for motor vehicles, comprises a bent wall 105, defining a housing 115, and an internal separator 130, inserted in the housing. The internal separator 130, which is notably corrugated, defines a plurality of fluid circulation channels 136. The wall 105 has large, for example plane, surfaces connected by radii 110. The wall of the tube notably has a cross section in the shape of a B.

[0035] In other words, in the example shown, once the tubes have been bent and then cut into sections, their thin wall has a cross section in the overall shape of a flattened B, i.e. with a base part extended laterally, by way of two connecting parts, by two coplanar, facing top parts parallel to the base part that terminate in adjacent end legs, facing perpendicularly toward the base part, and separated from the latter. Two longitudinal and parallel internal spaces or channels, corresponding to the loops of the B, are then defined in which are inserted, to their full length and in known manner, the two arrays of bends of an internal separator or disturber that are interconnected by a plane connecting part inserted in the space left between the end legs and the base part of the bent wall of the tube.

[0036] This inner spacer or each of these inner spacers notably also has the function of improving the thermal performance of the condenser and the mechanical strength of the tubes, which must resist not only the operating pressure when the loop is operating, which is of the order of 20 bar, but also that imposed by the specification, notably a tube bursting rating of up to 100 bar, for coolant fluids based on freon. Clearly, after the pre-assembled condenser (tubes, with internal separators, nested in the manifolds) is placed in a brazing furnace notably enabling fastening of the vertices of the longitudinal and corrugated bends of each internal separator to the internal face of the wall bent into the shape of a B of each tube, thanks to cladding provided on them (on the internal separator and/or on the wall of the tube) and the melting point of which is slightly lower than that of the material constituting the wall of the tubes and internal separators (for example aluminum alloy).

[0037] According to the invention, the tube 100 is configured so that the clearance is filled along at least one radius 110 between the wall 105 and the internal separator 130. The clearance is defined by the space that exists between the internal radius of the radius 110 of the tube 100 and the curvature of the end 134 of the internal separator 130. This means that the contact is continuous so that the clearance between the wall 105 and the internal separator 130 is entirely filled over all the length of the radius (i.e. along all the curvature of the radius). The tube is configured so that the clearance between the wall 105 and the internal separator 130 is for example filled along each radius 110.

[0038] In the embodiment shown, the internal separator 130 includes at least one flat at a vertex 132, notably at each vertex 132, said flat being in contact with the wall.

[0039] As already stated, the tube 100 has, for example, a section in the shape of a B and the wall has legs 120 joined at the level of the central part of said B-shaped section, at least one of the legs 120 being in contact with the internal separator 130.

[0040] The invention further concerns a method of producing a heat exchanger tube, notably for motor vehicle air conditioning system condensers. According to the invention, the tube 100 comprises a wall 105 defining a housing 115 and an internal separator 130 inserted in the housing 115. The internal separator 130 defines a plurality of fluid circulation channels 136. The wall has large, notably plane, faces of length L connected by radii of height H. As shown in FIGS. 1A and 1B, the length L corresponds to the dimension of the tube 100 in the direction of its longitudinal section. As shown in FIGS. 1A and 1B, the height H corresponds to the overall thickness of the tube 100, i.e. its thickness in the direction of its cross section. Of course, although this is not represented, the tube extends along its longitudinal axis, orthogonal to the plane of FIGS. 1A and 1B.

[0041] The method of the invention includes a first step in which the internal separator 130 is inserted into the housing 115 of the tube 100 with a clearance.

[0042] The method of the invention includes a second step in which the tube 100 is compressed in the direction of the height H. This compression is characterized in that it enables the tube to be compressed from a height H1 to a height H2 with H2<H1 and from a length L1 to a length L2 with L1 <L2, the tube 100 being configured after compression so that the clearance between the wall 105 and the internal separator 130 is at least partially filled.

[0043] The compression step may be generalized to a deformation step without limiting the scope of the protection of the present invention.

[0044] The compression or deformation step enables the wall 105 and the internal separator 130 to be calibrated. This step enables reshaping of the tube 100, the dimensions of which are modified. Before reshaping, there exists a clearance in the direction of the height H and also in the direction of the length L that enables the insertion of the internal separator 130. The dimensions of the wall 105 and the internal separator 130 can be defined beforehand so that this clearance exists despite the manufacturing tolerances of the two parts. A reshaping dimension is then defined in order to calibrate the tube 100 and the internal separator 130 and to fill at least one clearance or even all of the clearances provided for the purpose of this insertion.

[0045] The compression step enables the height H to be reduced and the length L to be increased. The effect of this is to fill the clearance along the radius between the wall 105 and the internal separator 130 and to enable brazing of the components. By virtue of their design, the increase in the dimension L of the wall 105 will be less than that of the internal separator 130.

[0046] In other words, the compression step makes it possible to increase the length dimension L of the internal separator 130 more than that of the wall 105. This makes it possible to fill the assembly clearance between the internal separator 130 and the inside radius of the tube nose 110. This moreover makes possible the brazing of the two components (i.e. wall 105 and internal separator 130) and thus to increase the mechanical strength, notably at the level of the tube nose 110.

[0047] The method could include a preliminary step in which the wall of the tube is produced by bending a sheet of material, for example, and after bending has a substantially closed section into which the internal separator is inserted.

[0048] In one embodiment, during the compression step of the method, the compression is exerted in a direction substantially orthogonal to the plane faces of the tube.

[0049] The compression step is configured so that the tube and its components, wall and/or internal separator, have the features referred to above, for example.

[0050] To be more precise, the compression step could be configured so that, after compression, the internal separator 130 includes a flat at one at least of its vertices 136, said flat being in contact with the wall.

[0051] The compression step thus enables the production of the plane areas at some or all of the vertices 136 of the internal separator 130. In other words, the consequences of the reduction in the height are crushing of the internal separator 130 generating a flat at its vertex and, depending on the magnitude of the calibration, modifying the angles of the bends of the internal separator 130. The effect of this is to guarantee the brazing between the internal wall of the wall 105 and the internal separator insert 130 as well as to increase the mechanical strength of this combination.

[0052] The compression step could also be configured so that the clearance between the wall 105 and the internal separator 130 is filled along each radius 110.

[0053] The compression step could further be configured so that, after compression, at least one of said legs 120 is in contact with the internal separator 130.