Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
  • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
  • F28F1/126—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element consisting of zig-zag shaped fins
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H3/00—Air heaters
  • F24H3/02—Air heaters with forced circulation
  • F24H3/04—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element
  • F24H3/0405—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element using electric energy supply, e.g. the heating medium being a resistive element; Heating by direct contact, i.e. with resistive elements, electrodes and fins being bonded together without additional element in-between
  • F24H3/0429—For vehicles
  • F24H3/0435—Structures comprising heat spreading elements in the form of fins
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H3/00—Air heaters
  • F24H3/02—Air heaters with forced circulation
  • F24H3/04—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element
  • F24H3/0405—Air heaters with forced circulation the air being in direct contact with the heating medium, e.g. electric heating element using electric energy supply, e.g. the heating medium being a resistive element; Heating by direct contact, i.e. with resistive elements, electrodes and fins being bonded together without additional element in-between
  • F24H3/0429—For vehicles
  • F24H3/0452—Frame constructions
  • F24H3/0476—Means for putting the electric heaters in the frame under strain, e.g. with springs
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/18—Arrangement or mounting of grates or heating means
  • F24H9/1854—Arrangement or mounting of grates or heating means for air heaters
  • F24H9/1863—Arrangement or mounting of electric heating means
  • F24H9/1872—PTC
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/02—Tubular elements of cross-section which is non-circular
  • F28F1/04—Tubular elements of cross-section which is non-circular polygonal, e.g. rectangular
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/02—Details
  • H05B3/06—Heater elements structurally combined with coupling elements or holders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F2275/00—Fastening; Joining
  • F28F2275/08—Fastening; Joining by clamping or clipping
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
  • H05B2203/02—Heaters using heating elements having a positive temperature coefficient
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
  • H05B2203/022—Heaters specially adapted for heating gaseous material
  • H05B2203/023—Heaters of the type used for electrically heating the air blown in a vehicle compartment by the vehicle heating system

Definitions

• the present invention relates to an electric heating block, such as a heating block intended for a motor vehicle.
• the invention also relates to a method of manufacturing such a heating block and a tube for such a heating block.
• Electric heating blocks comprising tubes intended to receive heating elements.
• Such heating elements include, for example, PTC effect resistors (for positive temperature coefficient).
• Such heating blocks also include heatsinks, such as for example fins, in thermal contact relationship with the heating elements.
• the tubes serve to electrically insulate the heating elements from the outside while allowing thermal conduction between the heating elements and the heatsinks.
• the heating elements are introduced into the tubes and then fixed by crushing the tubes against said heating elements.
• a crushing can be carried out by compression of the tubes in a unitary manner, the assembly with the dissipators being then carried out after compression of the tubes.
• Such a crushing can also be carried out by compression of the entire heating block, after assembly with the heatsinks.
• the fins must have sufficient mechanical strength so as not to be damaged during the crushing. According to known solutions, the fins are stiffened which complicates the heating block and limits the thermal performance.
• the invention aims to at least partially overcome the drawbacks mentioned above and for this purpose proposes an electric heating block comprising at least one fin intended to be traversed by a fluid and at least one tube accommodating one or more heating elements. electric, said tube having two large walls and two side walls, said fin being fixed to one and / or the other of the large walls of the tube, said heating elements being held in said tube by compression between said large walls by an operation of deformation of the side walls towards the inside of the tube.
• the deformation of the side walls of the tube thus makes it possible to maintain the heating elements without crushing the entire heating block and therefore without risk of damaging the fins.
• Such a heating block thus allows the use of fins of various types, in particular less resistant and more thermally efficient fins, without risking their crushing.
• the invention may also include any of the following characteristics, taken individually or in any technically possible combination:
• the side walls have an external face and an internal face, the external faces of the side walls of the tube having a shape curved towards the inside of the tube,
• the external faces have a central groove so as to facilitate the deformation of said tube in the event of lateral compression
• the internal faces of the side walls of the tube are configured so as to limit the deformation of said tube in the event of vertical compression
• the internal faces of the side walls of the tube have a substantially vertical profile
• the internal faces of the side walls of the tube are configured so that said internal faces have a thickness as regular as possible and the minimum of material at the level of the central groove, given the geometry of the external faces,
• the internal faces of the side walls of the tube have a substantially rounded profile
• the external faces of the side walls of the tube have two substantially straight sections and defining between them an angle forming the central groove at their junction
• the tube has an internal groove, at the connection edges, the internal groove acting as a hinge,
• the large walls have an external surface compatible with the geometry of the at least one fin between said connection edges, - the large walls have a flat external surface between the connection edges,
• edges have an external face of square profile and an internal face of hollowed out profile with respect to an internal face of the large walls and the internal face of the side walls, so that the internal face of the connection edge defines said groove,
• the surface of the internal face of the large wall is substantially equal to the surface of the external face of said large wall so that the heat exchange surface between the electric heating elements and the fins is optimal
• each of the walls of the tube has a substantially equal thickness
• the fin is fixed to one and / or the other of the large walls of the tube by brazing
• the fin is fixed to one and / or the other of the large walls of the tube by gluing
• the fins have a wavy shape
• the fins include louvers intended to promote heat exchange.
• the invention also relates to a method of manufacturing an electric heating block comprising:
• the method according to the invention can also include any of the following characteristics, taken individually or in any technically possible combination:
• the deformation step is carried out by applying pressure at the external faces of the side walls of the tube along an axis substantially orthogonal to said side walls, the pressure being applied by a pressure tool,
• the pressure tool comes into contact with the side walls of the tube at a central groove so that the deformation of the side walls of the tube is controlled
• the assembly step is carried out by gluing
• the assembly step is performed simultaneously for all of the tubes and fins of the heating block.
• the invention also relates to a tube intended for the heating block as described above, the tube having two large walls and two side walls, each of the large walls having an external face intended to come into contact with a fin and an internal face. intended to come into thermal contact with electric heating elements, the side walls having a pre-configuration curved towards the inside of the tube facilitating a deformation operation with a view to accentuating their curving so as to maintain said heating elements in said tube by compression of said heating elements between said large walls.
• FIG. 1 partially illustrates schematically in cross-sectional view an electric heating block according to the invention before the introduction of the heating elements
• FIG. 2 partially illustrates schematically in cross-sectional view an electric heating block according to the invention after the introduction of the heating elements and before the deformation step
• FIG. 3 partially illustrates schematically in cross-sectional view an electric heating block according to the invention
• FIG. 4 is a perspective view of a tube according to the invention, before deformation
• FIG. 5 is a schematic illustration of the different steps of the method according to the invention.
• the invention relates to a block 1 of electric heating.
• Said heating block 1 is intended to be supplied with electric current to heat an air flow F passing through said block 1.
• Said electric heating block 1 advantageously has a substantially parallelepiped configuration, extending on the surface. It is intended to be positioned transversely to the air flow F. More precisely, said air flow F is intended to be oriented perpendicular to said block 1.
• the heating block comprises at least one fin 10, intended to be traversed by a fluid, in particular the air fluid F, and at least one tube 20 receiving one or more electric heating elements 50.
• the heating block here comprises several tubes 20 and several fins 10 stacked alternately in a vertical stacking direction in the figure.
• the tubes 20 are positioned parallel to each other in a direction perpendicular to the plane of the figure.
• Said tubes 20 make it possible to electrically isolate and protect the said heating element (s) 50 from the outside.
• the fins 10 form heat sinks making it possible to increase the surface area for exchange with the fluid.
• each tube 20 comprises several heating elements 50 located one after the other in a direction perpendicular to the plane of FIGS. 1 to 3. Said heating elements 50 are advantageously distributed regularly along the tubes 20.
• the tubes 20 form with the heating elements 50 heating units.
• said heating units are selectively supplied with current.
• the heating elements 50 of each heating unit are supplied with current independently of the heating elements 50 of the others heating units and can therefore be traversed by a different current, in particular by its intensity, from the current flowing through the other heating units.
• the heating units further include here electrodes 52, located on either side of the heating elements 50 for their supply of electric current.
• Said heating units also comprise layers of material 54, electrically insulating and thermally conductive, said layers 54 being located between one of the electrodes 52 and a large wall 21 of the tube 20. In this way, the tube 20 is electrically isolated from the electrodes 52 and heating elements 50 but thermally in contact with them.
• said heating elements 50 are electrically connected in parallel, in particular using the electrodes 52.
• the fins 10 are in thermal contact relation with the tubes 20. Said fins 10 are positioned between said tubes 20, in particular between the large walls 21 of said tubes 20.
• the tubes 20 have two side walls 24 connecting the large walls 21.
• the large walls 21 each have an external face 22 on which the fin 10 is fixed and an internal face 23 intended to come into thermal contact with the heating elements 50.
• a contact thermal implies a thermal exchange between the elements, even if these elements are not directly in physical contact with each other.
• the large walls 21 have the function of transmitting the heat generated by the electric heating elements 50 to the fins 10.
• the tube 20 can be of any material suitable for use in a block 1 of electric heating.
• the tube 20 is made of aluminum and / or aluminum alloy.
• the heating elements 50 are held in the tube 20 by compression of the large walls 21 in the direction of said heating elements 50.
• This compression of the large walls 21 results from an operation of deformation of the side walls 24 towards the interior of the tube 20.
• the large walls 21 approach each other and thus compress the heating elements 50 located in the tube 20.
• the side walls 24 have a configuration curved towards the inside of the tube 20.
• the deformation of the side walls 24 of the tube 20 allows the displacement of the large walls 21 in the direction of the heating elements 50 without having to crush the heating block 1 in a direction perpendicular to the large walls 21 of the tubes 20 and therefore without risk of damaging the fins 10.
• the displacement of the large walls 21 of the tube 20 results in compression of the tube and maintenance of the heating elements 50.
• the fins 10 can be fixed to one and / or the other of the large walls 21 before the tubes 20 are not deformed in order to maintain the heating elements 50.
• the fins 10 fixed on one and / or the other of the large walls 21 do not undergo compression and are not liable to be damaged.
• a heating block 1 makes it possible to use fins 10 which are less resistant and more thermally efficient than in a conventional heating block.
• the fact of being able to fix the fins 10 to the tubes 20 makes it easier to handle the block 10 during its manufacture.
• FIG. 4 illustrates a tube 20 intended for a heating block 1 according to the invention.
• a tube 20 has not yet undergone deformation. However, all of the elements and characteristics of the tube 20 before deformation are found on this same tube 20 after deformation, once integrated into the heating block 1.
• a tube 20 after deformation is notably illustrated in FIG. 3.
• the side walls 24 of the tube 20 each have an external face 25 and an internal face 28.
• the deformation of the side walls 24 is produced by the application of pressure at the level of the external faces 25 along an axis substantially orthogonal to said side walls 24
• the application of pressure to the side walls 24 can be carried out by a pressure tool.
• the external faces 25 have a shape curved towards the inside of the tube and a central groove 26.
• the presence of a central groove 26 associated with a side wall 24 having a curved configuration makes it possible to precisely control the deformation of the tube 20 in the event of lateral compression.
• the curved shape towards the inside of the tube makes it possible to reduce the lateral force necessary to deform the tube 20 and the groove 26 ensures that the side walls 24 are deformed at the level of said groove.
• the internal faces 28 of the side walls 24 of the tube 20 have a substantially vertical profile, if necessary slightly rounded. Such a profile makes it possible to limit the compression deformation of the side walls 24 in the event of vertical compression of said tube 20, once integrated into the block 1.
• such a profile also allows the side walls 24 to have a thickness as regular as possible and the minimum of material at the level of the central groove (26), given the geometry of the external faces (25). Finally, such a profile facilitates the flexural deformation of the side walls 24 in the event of lateral compression.
• the external faces 25 of the side walls 24 have two substantially straight sections 27. These straight sections 27 define between them an angle forming the central groove 26.
• the sections 27 act as a guide and facilitate the positioning of the pressure tool at the groove 26.
• the pressure tool is housed at the level of the groove 26.
• the presence of sections 27 further facilitates the control of the deformation of the side wall 24.
• the large walls 21 and the side walls 24 of the tube 20 meet at the connection edges 30.
• the edges 30 are, like the large walls 21 and the side walls 24, made from material of the tube 20. Even if several parts are defined, the tube is a single piece.
• the tube 20 has an internal groove 35, at the level of said connection edges 30.
• the large walls 21 have an external face 22 compatible with the geometry of the fin 10 so as to maximize their contact surface.
• the large walls 21 have a planar external face 22 between said connection edges 30.
• the dissipator 10 does not extend over the entire surface of the external face 22 of the large wall 21 so as to leave a zone of gripping.
• This gripping zone extends over a distance of between 0.1 and 2 mm starting from the connection stops 30. Said gripping zone allows the use of a gripping tool in order to manipulate the block 1 at the level of the tube 20 and in particular during the deformation of said tube 20.
• connection edges 30 have an external face 32 of substantially square profile and an internal face 34 of hollowed out profile with respect to the internal face 23 of the large walls 21 and the internal face 28 of the side walls 24, so that the face internal 34 of the connection edge 30 defines the groove 35.
• substantially square is meant forming a right angle or having a very small radius of curvature.
• the fin 10 is fixed to one and / or the other of the large walls 21 of the tube 20 by brazing.
• This technique of fixing the fins has several advantages.
• the brazing of the fins 10 on the tube 20 makes it possible to improve the heat exchanges between the heating elements 50 and the fins.
• the material of the tube 20 for example aluminum, will be more malleable and more easily deformable than before the brazing step, even after it has dropped to ambient temperature. This decreases the elastic relaxation that the material could have after deformation.
• this state of matter guarantees tight contact between the tube 20 and the heating elements 50 and therefore better heat exchange.
• Brazing also ensures a better life for the tube 20 because it will be less sensitive to temperature and relaxation variations during the life of the heating block 1.
• a soldering step prior to the deformation of the side walls 24 makes it possible to reduce the force necessary for the deformation.
• Conventionally when the side walls of a tube are deformed, the horizontal walls are deformed in turn, in particular towards the outside of the tube. This parasitic deformation is called buckling. This buckling thus prevents optimal thermal contact between the heating elements and the horizontal heat exchange walls.
• the fins 10 in a heating block 1 according to the invention, reinforce the rigidity of the large walls 21 of the tube 20 and help them to remain straight during the operation of deformation of the side walls 24.
• the large walls 21 are not necessarily thicker compared to the side walls 24 of the same tube 20.
• the tube 20 of a heating block 1 according to the invention is even more stable against buckling than a single more rigid tube of the same thickness. This makes it possible to reduce the thickness of the walls of the tube 20 in order to optimize their weight and their cost because they do not need to be particularly thick to avoid buckling.
• a heating block 1 makes it possible to use fins 10 which are less resistant and more thermally efficient than in a conventional heating block.
• the fins 10 of the heating block 1 are flexible before assembly. These are in particular wavy fins.
• the fins 10 include louvers intended to promote heat exchange.
• FIG. 4 another aspect of the invention relates to the tube 20 as such.
• the tube 20 shown in FIG. 4 is a tube intended for a heating block 1 according to the invention which has not yet undergone a deformation operation. It is identical to the tube 20 of the heating block 1 shown in Figures 1 and 2 which has not yet undergone a deformation operation.
• the tube 20 intended for the heating block 1 as described above has two large walls 21 and two side walls 24, each of the large walls 21 having an external face 22 intended to come into contact with a fin 10 and a face internal 23 intended to come into thermal contact with electric heating elements 50.
• the large walls 21 are advantageously substantially parallel to one another.
• the tube 20 illustrated in FIG. 4 also comprises side walls 24 having two substantially straight sections 27 and defining between them an angle forming a central groove 26.
• the side walls 24 have a pre-configuration curved towards the inside of the tube. This curvature is accentuated by the operation of deformation of the side walls 24.
• Said tube 20 also includes edges 30 for connection between the side walls 24 and the large walls 21. Said edges 30 having an outer face 32 of substantially square profile and a internal face 34 of profile hollowed out with respect to the internal face 23 of the large walls 21 and the internal face 28 of the side walls 24, so that the internal face 34 of the connection edge 30 defines a groove 35.
• the surface of the internal face 23 of the large wall 21 of the tube 20 is substantially equal to the surface of the external face 22 of said large wall 21.
• the heat exchange surface between the electric heating elements 50 and the fins 10 is maximum, after assembly.
• another aspect of the invention relates to a method for manufacturing a heating block 1 as described above.
• Such a method comprises a step (El) of assembling at least one fin 10 and at least one tube 20.
• the fin 10 is intended to be traversed by a fluid.
• the tube 20 is intended to accommodate electric heating elements 50 and has two large walls 21 and two side walls 24.
• the assembly step (El) makes it possible to fix the fin 10 on one and / or the other large walls 21 of the tube 20.
• Said method also includes a step (E2) of introducing the heating elements 50 into the tube 20.
• the method comprises a step (E3) of deformation of the side walls 24 of the tube 20 so as to fix the heating elements 50 in the tube 20.
• Such a method makes it possible to produce an electric heating block 1 as described above.
• the assembly step (E1), the introduction step (E2) and the deformation step (E3) are consecutive and follow each other in this order.
• FIG. 1 illustrates a heating block 1 according to the invention, after the assembly step (E1) and before the steps (E2) and (E3).
• the fins 10 are here fixed on the large walls 21 of the tube 20.
• FIG. 2 illustrates a heating block 1 according to the invention during step (E2) of introduction of the heating elements 50 and before the deformation step (E3).
• the heating elements 50 are here introduced into the tube 20 but they are not yet held in position by compression of the large walls 21.
• FIG. 3 illustrates a heating block 1 according to the invention after step (E3) deformation.
• the side walls 24 have here been deformed towards the inside of the tube 20, said deformation then causing the large walls 21 to move towards one another, which makes it possible to maintain the heating elements 50 by compression in the tube 20.
• the deformation step (E3) is carried out by the application of pressure at the level of the external faces 25 of the side walls 24 of the tube 20 along an axis substantially orthogonal to said side walls 24.
• the pressure exerted can in particular be applied by a pressure tool.
• the pressure tool comes into contact with the side walls 24 of the tube 20 at a central groove 26.
• a groove 26 makes it possible to precisely control the deformation of the tube 20.
• said groove 26 acts as a preform and the side walls 24 fold along said groove 26.
• the application of pressure during the deformation step (E3) is carried out simultaneously for the two side walls 24 of the same tube 20.
• the large walls 21 of the tube 20 remain substantially parallel during the deformation, which prevents any separation of the fins 10 and the tube 20.
• the application of pressure during the deformation step (E3) is carried out successively for each of the tubes 20 of the heating block 1. Indeed, if this deformation step were to be carried out simultaneously for a plurality of tubes 20 of the same block, the simultaneous bringing together of a plurality of large walls 21, two by two, would result in separation of the fins 10 and the tubes 20.
• the assembly step (E1) can be carried out by a plurality of techniques, such as for example by gluing.
• the assembly step (El) is carried out by brazing.
• This assembly technique makes it possible inter alia to confer a tight contact and to improve the heat exchanges between the heating elements 50 and the fins 10.
• an assembly step (El) prior to the deformation of the side walls 24 and produced by brazing makes it possible to reduce the force necessary for the deformation of said side walls 24.
• the assembly step (E1) is carried out simultaneously for all of the tubes and fins of the heating block.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Geometry (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Resistance Heating (AREA)
• Instantaneous Water Boilers, Portable Hot-Water Supply Apparatuses, And Control Of Portable Hot-Water Supply Apparatuses (AREA)

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Publications (1)

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Citations (6)

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• 2018
  • 2018-06-28 FR FR1855842A patent/FR3083300B1/fr active Active
• 2019
  • 2019-06-19 WO PCT/FR2019/051496 patent/WO2020002797A1/fr active Application Filing
  • 2019-06-19 CN CN201980041931.7A patent/CN112771318B/zh active Active
  • 2019-06-19 EP EP19790607.6A patent/EP3814692B1/fr active Active

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