EP2425193B1 - Heat exchanger - Google Patents
Heat exchanger Download PDFInfo
- Publication number
- EP2425193B1 EP2425193B1 EP10726891.4A EP10726891A EP2425193B1 EP 2425193 B1 EP2425193 B1 EP 2425193B1 EP 10726891 A EP10726891 A EP 10726891A EP 2425193 B1 EP2425193 B1 EP 2425193B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- conduit
- heat exchanger
- fluid flow
- tube
- inner conduit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000003507 refrigerant Substances 0.000 claims description 48
- 239000012530 fluid Substances 0.000 claims description 44
- 238000000034 method Methods 0.000 claims description 25
- 230000008569 process Effects 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 238000005452 bending Methods 0.000 claims description 7
- 230000003247 decreasing effect Effects 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 230000004323 axial length Effects 0.000 claims 7
- 238000005096 rolling process Methods 0.000 claims 1
- 238000004378 air conditioning Methods 0.000 description 10
- 239000007788 liquid Substances 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 238000003466 welding Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 3
- 238000005219 brazing Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000002788 crimping Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/10—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged one within the other, e.g. concentrically
- F28D7/106—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged one within the other, e.g. concentrically consisting of two coaxial conduits or modules of two coaxial conduits
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
- B21D53/06—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of metal tubes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B40/00—Subcoolers, desuperheaters or superheaters
-
- 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
- F28F1/06—Tubular elements of cross-section which is non-circular crimped or corrugated in cross-section
-
- 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
- F28F1/08—Tubular elements crimped or corrugated in longitudinal section
-
- 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
- F28F1/34—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 and extending obliquely
- F28F1/36—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 and extending obliquely the means being helically wound fins or wire spirals
-
- 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
- F28F1/42—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element
-
- 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
- F28F1/42—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being both outside and inside the tubular element
- F28F1/424—Means comprising outside portions integral with inside portions
- F28F1/426—Means comprising outside portions integral with inside portions the outside portions and the inside portions forming parts of complementary shape, e.g. concave and convex
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F2210/00—Heat exchange conduits
- F28F2210/06—Heat exchange conduits having walls comprising obliquely extending corrugations, e.g. in the form of threads
Definitions
- the invention relates generally to the technical field of heat exchangers and particularly, but not exclusively, to internal heat exchangers and more particularly those used for use air-conditioning systems for automotive applications.
- Air-conditioning systems of motor vehicles are frequently equipped with a so-called internal heat exchanger.
- Such heat exchangers may be used to increase the operating efficiency of the system by pre-heating the refrigerant supplied to the suction side of a compressor of the air-conditioning system and at the same time cooling the refrigerant (liquid side) being conveyed to an expansion device.
- An inner heat exchanger is disclosed in DE10 2006 017 816 B4 . This document discloses a single piece extruded aluminium heat exchanger element. In this one extruded profile channels are formed for conveying both liquid side and suction side refrigerant.
- extruded heat exchanger elements of this type offer high levels of heat exchange between the suction and the liquid sides, they suffer from certain drawbacks: they require machining and/or cleaning before they can be used; welding or brazing must be used in order to connect the suction line to the profile; and, the geometry of the heat exchanger is fixed by the extrusion tool, meaning that new tools must be developed for a new applications requiring different extrusion profiles.
- the heat exchanger In order to achieve a desired heat transfer between the suction side and the liquid side the heat exchanger must have a given heat exchange area. Sometimes, space is at a premium, for example in automotive applications. In such cases it is desirable to be able to use heat exchangers of reduced outer dimensions. This often means that it is required to form or bend the heat exchanger as a U-shaped pipe or into other shapes so that it may be installed in a given space. This in turn requires that the heat exchanger pipe be designed in a sufficiently bendable manner so that it may be deformed without collapsing its fluid conveyance channels. Moreover, it may also mean that the outer diameter of the heat exchanger is limited or constrained.
- a heat exchanger and a method in accordance with the preamble of claims 1 and 9 are known from US 4,194,560 .
- Dent portions are alternately formed on the outside face of the inner tube.
- the inner tube is then fitted within the outer tube to form a space between outer tube and inner tube wherein oil flows in zigzag fashion to assure heat transfer. Due to the dents formed in the inner tube, the cross-sectional area of the inner tube is reduced in relation to the original tube. This results in undesirable higher pressure drop in the inner tube. Moreover will the described increased contact area also increase the refrigerant pressure drop between the outer and inner tube.
- the air conditioning system 1 includes a compressor 2, which may be driven, for example, by the engine of the vehicle or by a separate electric motor or the like.
- the compressor 2 has an inlet 4, connected to a low pressure line 21, via which where the compressor 2 takes in refrigerant, or coolant, at low pressure.
- the compressor 2 also has an outlet 3, via which pressurized refrigerant is output, into a high pressure line 5.
- the high pressure line 5 leads to a cooling device 6 where the compressed and thus heated refrigerant is cooled and condensed. Therefore, the cooling device 6 is also referred to as a condenser.
- the refrigerant used is R-134a that works at low pressure.
- the refrigerant is discharged to another high pressure line 8 that leads to a high-pressure inlet 9 of an internal heat exchanger 11.
- the internal heat exchanger 11 has a high-pressure outlet 12 that is in turn connected to an expansion valve 15 via a high pressure line 14.
- the expansion valve 15 relaxes the refrigerant that is introduced into an evaporator 16.
- the refrigerant evaporates in the evaporator 16 and, as a result, absorbs thermal energy from the environment; in this example, cooling the air supplied to the interior of the motor vehicle.
- the resultant refrigerant vapor is then transported from the evaporator 16, via a low-pressure line 17, to the low-pressure inlet 18 of the internal heat exchanger 11.
- This refrigerant vapor flows through the internal heat exchanger 11 in a counter-current direction to the refrigerant that is being fed through the high-pressure inlet 9. In so doing, the refrigerant vapor cools the pressurized refrigerant, thus itself becoming heated.
- the refrigerant vapor is discharged, having been heated, at the low-pressure outlet 19 of the internal heat exchanger 11. It is then conducted, via a low-pressure line 21, to the inlet 4 of the compressor 2.
- the internal heat exchanger 11 allows the temperature of the refrigerant flowing to the compressor 2 to be increased, which in turn increases the temperature of the refrigerant at the outlet 3 of the compressor. Therefore, the cooling device 6 releases a greater amount of thermal energy. At the same time, the internal heat exchanger 11 lowers the temperature of the refrigerant fed to the evaporator 16, thus providing an improved heat transfer between the evaporator 16 and ambient air. In this manner, the internal heat exchanger 11 may be used to increase the efficiency of the air conditioning system.
- Fig. 2 shows a further schematic illustration of the internal heat exchanger 11.
- it is shown as a U-shaped bent pipe 22.
- the bent pipe 22 has two legs 23, 24, that are bent away from each other at their upper ends.
- the high-pressure inlet 9 and the high-pressure outlet 12 are in fluid connection with the remainder of the system 1 at position 26a.
- the low-pressure inlet 18 and the low-pressure outlet 19 of the internal heat exchanger 11 are in fluid connection with the remainder of the system 1 at position 26b.
- positions 26a and 26b are located at or relatively close to the terminations of at the upper ends of the bent pipe 22.
- FIG. 3a shows a perspective view of the internal heat exchanger 11 of a first embodiment in its assembled state but prior to being bent into its final U-shaped configuration.
- the internal heat exchanger 11 includes an outer tube 30, and inner tube 32, of which end portions 32a and 32b are visible from this figure Both the outer tube 30 and inner tube 32 being designed as refrigerant conduits.
- the inner tube 32 is located inside and runs the entire length of the outer tube 30.
- the internal and external diameters of the outer tube 30 are 18mm and 20mm, respectively.
- the internal and external diameters of the parts of the inner tube 32 that extend beyond the outer tube 30 and can be seen in the figure are 12mm and 15mm, respectively. It will be understood that the dimensions of the outer tube 30 and inner tube 32 are selected for a given application and will therefore change in dependence upon application.
- the inner diameter of the outer tube 30 may from range 9-19mm for automotive or car applications, 20-39mm for bus applications and, 23-50mm for train applications.
- the outer tube is 24mm outer diameter with a 20mm inner diameter.
- the starting material, or base tube, for the inner tube is 18mm outer diameter with an inner diameter of 15mm.
- the high-pressure inlet 9 and the high-pressure outlet 12 of the internal heat exchanger 11 are connected to a suitable orifice in the outer tube 30 using a conventional process such as welding or brazing.
- the weld points are referenced 34 in the figure.
- a fluid connection is formed between the high-pressure inlet 9 and the high-pressure outlet 12 via the outer tube 30.
- the connection orifices may be machined, or otherwise manufactured using any convenient process.
- the outer tube 30 may be used as a connection sleeve which allows the system costs to be reduced.
- the extreme end points 36 of the outer tube 30 are joined to inner tube 32 to ensure that the joint is effectively sealed against leakage of the refrigerant.
- a conventional process may be used; for example o-rings, crimping and or welding or brazing.
- Fig. 3b shows a photograph of an example of an internal heat exchanger 11 similar to that shown in Fig. 3a
- the inner tube 32 has end portions 32a and 32b that are circular. These respectively form the low-pressure inlet 18 and the low-pressure outlet 19 of the internal heat exchanger 11.
- the end portions 32a and 32b are unmodified base tube material. Therefore end portions 32a and 32b may be configured to be the required lengths to provide the function of low pressure tubes 21 and 17, shown in Fig. 1 . This in turn means that no suction side connection tubes are needed; thus obviating the need for costly connection processes, such as welding and eliminating the risk of refrigerant leakage at such connection points.
- a central portion 32c that has been deformed into a helical shape along its longitudinal axis.
- a photograph of the exterior of a section of the deformed portion 32c of the inner tube of the internal heat exchanger 11 according to the first embodiment is shown in Fig. 3c .
- the central portion 32c may be deformed using any convenient deforming procedure. In the present example it is deformed through a repeated clamping process. However, other deforming processes or apparatus, such as a press or hammer, may be used. In this example, the clamping process is implemented using shaped opposing clamping surfaces to achieve the desired exterior profile of the portion 38b.
- the marks 38a left in the outer surface of the deformed portion 32c by the action of the clamping process may be seen in Fig. 3c . Furthermore, it can be seen from Fig. 3c that the deformed portion 32c has a helical profile. This helical profile can be more clearly seen from the schematic illustration of a section of portion 32c illustrated in Fig. 3d .
- FIG. 4 shows an image schematically illustrating a part of the inner tube 32, including part of central portion 32c, arranged about its longitudinal axis 42.
- the left hand end 32a of the inner tube 32 is not deformed and is circular is cross section.
- portion 44a Adjacent the left hand end 32a end of the inner tube 32 is portion 44a that has been deformed to an approximate elliptical shape of predetermined dimensions. These dimensions may be controlled using the parameters of the deforming process; for example the linear extent of the clamping operation and the shape, dimensions and material properties of the clamping surfaces.
- the major axis 46a of the elliptical portion 44a is shown orientated vertically.
- the inner tube 32 is advanced a fixed predetermined distance along its longitudinal axis 42 to bring the portion 44b of the tube adjacent the clamping surfaces and the inner tube 32 is rotated by a fixed angle in a given direction about its longitudinal axis; in this example 45 degrees.
- the clamping operation is then repeated.
- This process is then repeated along the desired length of central portion 32c of the inner tube 32, as is illustrated by deformed portions 44b - 44f. In this manner an approximate helical structure of approximately fixed helical pitch and approximately constant elliptical cross section may be formed.
- the central portion 32c of the inner tube 32 is free or substantially free of projections and is relatively smooth in both its circumferential direction and its longitudinal direction.
- the inventors have found that this process of manufacture may be largely automated by using a bending machine set to zero bend radius.
- the creation of the helical structure of the central portion 32c of the inner tube 32 may be a relatively rapid and inexpensive process.
- inner tube 32 is assembled with the outer tube 30, by inserting the inner tube 32 inside the outer tube 30.
- the fit between the inner tube 32 and the outer tube 30 may be any convenient fit, such as a loose fit or a slight interference fit.
- inner tube 32 and the outer tube 30 may be assembled by hand or be automated.
- the welding or braising, including crimping if this is required, of the extreme end points 36 of the outer tube 30 to inner tube 32 may then be carried out. This may be done in the region where the non-deformed end sections 32a and 32b of the inner tube 32 transition into the adjacent deformed portion 32c.
- Fig. 5c shows a cross sectional view, in the direction of arrows A-A shown in Fig. 3a , of the internal heat exchanger 11, and illustrates the inner tube 32 and the outer tube 30 once assembled.
- the inner tube 32 forms an approximate ellipse, the major axis of which is approximately equal to the internal diameter of the outer tube 30; i.e. 18mm.
- the cross sectional profile of the inner tube 32 could be varied either to meet heat exchange requirements or in order to meet manufacturing requirements.
- an ellipse as is illustrated in Fig. 5a could be used.
- Other examples could include a triangular or quadrilateral shape, such as an approximate square as is illustrated in Fig. 5b could also be used.
- other cross sectional profiles may be contemplated, which have increased numbers of sides.
- the inner tube 32 contacts the inner surface of outer tube 30 at points 56a and 56b, thus forming two substantially line contacts between the outer surface of the inner tube 32 and the inner surface of outer tube 30 which run the entire length of the helical structure of the central portion 32c of the inner tube 32.
- two refrigerant fluid flow channels 52a and 52b are formed between the outer surface of the inner tube 32 and the inner surface of outer tube 30.
- the fluid flow channels 52a and 52b carry liquid side refrigerant.
- a certain degree of fluid connection between the fluid flow channels 52a and 52b may be permitted. The extent of this permitted fluid connection may be dependent upon the application.
- a third refrigerant fluid flow channel 50 lies on the inside of the inner tube 32.
- the third refrigerant fluid flow channel 50 carries refrigerant supplied to the suction side of the compressor.
- the three refrigerant fluid flow channels run substantially the entire length of the helical structure of the central portion 32c of the inner tube 32.
- the third refrigerant fluid flow channel 50 has a cross sectional area which is substantially equal to, or is only marginally reduced relative to the cross sectional area of the base circular tube from which it is formed, and from which the remainder of the suction side, low pressure lines of the air conditioning system 1, are made. This means that the pressure drop caused per unit length of the fluid flow channel 50 is substantially the same as, or not significantly increased relative to, that of the base circular tube from which it is formed, such as low pressure line 21.
- the inventors have surprisingly discovered that the creation of the helical structure of the central portion 32c of the inner tube 32 does not cause a significant or measurable drop in pressure in the fluid flow channel 50 relative to a correspondingly profiled tube with no helical structure.
- the surprising lack of pressure drop in the suction side of the internal heat exchanger 11 of the present embodiment may strongly contribute to the efficiency of the air conditioning system 1.
- the internal heat exchanger 11 of the present embodiment Whilst in applications for which the internal heat exchanger 11 of the present embodiment is designed benefit from no significant drop per unit length in pressure in the fluid flow channel 50 relative to a correspondingly profiled tube with no helical structure, it will be appreciated that in other applications of the invention a greater pressure drop may be permitted. This may be for example, 2%, 5% or 7% increase relative to a correspondingly profiled tube with no helical structure. However, in some embodiments for certain applications, the suction side pressure drop per unit length of the internal heat exchanger 11 may be up to 30% higher than that of the normal suction side line. In other embodiments this figure may be 10% or 20%.
- the area across which heat may be exchanged between fluid flow channel 50 and each of fluid flow channels 52a and 52b is large, being approximately equivalent to half of the external area of the inner tube 32.
- the efficiency of heat exchange between the flow channel 50 and each of fluid flow channels 52a and 52b is increased.
- the fluid flow channels 52a and 52b are approximately crescent shaped, having a relatively small height or thickness in the radial direction and a relatively high length of contact with the external circumference of the inner tube 32. This length of contact is illustrated, in the case of fluid flow channels 52a by line 58 in the figure.
- this line of contact provides a convex heat transfer surface (the external surface of the inner tube 32) against which the fluid in fluid flow channels 52a and 52b flows; and thereby a large and efficient heat exchange surface over the length of the fluid flow channels 52a and 52b.
- Fig. 6 illustrates the flow of refrigerant in the internal heat exchanger 11 according to the present embodiment.
- the refrigerant flowing in refrigerant fluid flow channel 50 is referenced 60 and the refrigerant flowing in refrigerant fluid flow channels 52a and 52b is referenced 62a and 62b, respectively.
- the refrigerant flowing in refrigerant fluid flow channels 52a and 52b follows a helical path along the internal heat exchanger 11 and completes three complete cycles around the fluid in fluid flow channel 50.
- Fig. 7 illustrates part of the image of Fig. 4 illustrating several deformed portions 44 of the inner tube 32; where:
- the heat transfer surface, the flow velocity and therefore the heat transfer may be adjusted by modifying the geometry of the inner tube 32.
- the parameters "a”, “b” and “f” determine the cross section of the liquid flow channels 52a and 52b and therefore the flow velocity and the heat transfer coefficient.
- the parameters "c” and “e” determine heat exchange, or contact length and therefore the liquid side heat transfer surface.
- the internal heat exchanger 11 should have sufficient bending stability.
- the bending stability of the internal heat exchanger 11 may be increased by decreasing the value of parameter " f '.
- the contours of the inner tube 32 can be placed anywhere along, or even along only a part of, the length of the inner tube 32.
- heat transfer may be adjusted by changing the geometry of the interface between the inner tube 32 and the outer tube 30, and this may be done without significantly changing the forming tool, such as a clamp, or process used. This provides considerable flexibility in terms or manufacturing. Heat exchanger applications with different performance criteria may be achieved without having to significantly modify the manufacturing process or tooling.
- the inner tube may be made from standard tubing material, it is low cost. No expensive extrusions are required and no suction side connection tubes are needed, which may help to ensure that manufacturing is simplified and reliability of the system is increased.
- Bending flexibility may be adjusted by altering the geometry of the deformed tube.
- the outer tube 30 may be used as a connection sleeve which further allows the system costs to be reduced. Despite the fact that that low-pressure channel may be particularly large, reducing the tendency for suction side pressure drop, a relatively small outside diameter may be achieved.
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- Physics & Mathematics (AREA)
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- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Geometry (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Description
- The invention relates generally to the technical field of heat exchangers and particularly, but not exclusively, to internal heat exchangers and more particularly those used for use air-conditioning systems for automotive applications.
- Air-conditioning systems of motor vehicles, for example, are frequently equipped with a so-called internal heat exchanger. Such heat exchangers may be used to increase the operating efficiency of the system by pre-heating the refrigerant supplied to the suction side of a compressor of the air-conditioning system and at the same time cooling the refrigerant (liquid side) being conveyed to an expansion device. One example of an inner heat exchanger is disclosed in
DE10 2006 017 816 B4 . This document discloses a single piece extruded aluminium heat exchanger element. In this one extruded profile channels are formed for conveying both liquid side and suction side refrigerant. Whilst, extruded heat exchanger elements of this type offer high levels of heat exchange between the suction and the liquid sides, they suffer from certain drawbacks: they require machining and/or cleaning before they can be used; welding or brazing must be used in order to connect the suction line to the profile; and, the geometry of the heat exchanger is fixed by the extrusion tool, meaning that new tools must be developed for a new applications requiring different extrusion profiles. - In order to achieve a desired heat transfer between the suction side and the liquid side the heat exchanger must have a given heat exchange area. Sometimes, space is at a premium, for example in automotive applications. In such cases it is desirable to be able to use heat exchangers of reduced outer dimensions. This often means that it is required to form or bend the heat exchanger as a U-shaped pipe or into other shapes so that it may be installed in a given space. This in turn requires that the heat exchanger pipe be designed in a sufficiently bendable manner so that it may be deformed without collapsing its fluid conveyance channels. Moreover, it may also mean that the outer diameter of the heat exchanger is limited or constrained.
- In view of such design requirement it would therefore be desirable to provide a heat exchanger that overcomes at least some of the above mentioned problems.
- A heat exchanger and a method in accordance with the preamble of
claims 1 and 9 are known fromUS 4,194,560 . Dent portions are alternately formed on the outside face of the inner tube. The inner tube is then fitted within the outer tube to form a space between outer tube and inner tube wherein oil flows in zigzag fashion to assure heat transfer. Due to the dents formed in the inner tube, the cross-sectional area of the inner tube is reduced in relation to the original tube. This results in undesirable higher pressure drop in the inner tube. Moreover will the described increased contact area also increase the refrigerant pressure drop between the outer and inner tube. - According to the present invention there is provided a heat exchanger and a method of manufacturing of a heat exchanger as defined in the appended claims.
- The above and other aspects, features and advantages of the invention will be apparent from the following detailed description of illustrative embodiments which is to be read in connection with the accompanying drawings, in which:
-
Fig. 1 is a schematic diagram of an air conditioning system for an automotive application comprising an internal heat exchanger; -
Fig. 2 shows a schematic illustration of the internal heat exchanger shown inFig. 1 in a U-shaped configuration; -
Fig. 3a shows a perspective view of an internal heat exchanger according to a first embodiment of the invention in its assembled state but prior to being bent into a U-shaped configuration; -
Fig. 3b shows a photograph of the exterior of an internal heat exchanger according to the first embodiment; -
Fig. 3c shows a photograph of the exterior of a section of the deformed portion of the inner tube of the internal heat exchanger according to the first embodiment; -
Fig. 3d shows a schematic illustration of the exterior of a section of the deformed portion of the inner tube of the internal heat exchanger according to the first embodiment, more clearly showing its helical structure; -
Fig. 4 is an image schematically illustrating part of the inner tube of the internal heat exchanger according to a first embodiment, which illustrates one exemplary method of creating a helical structure in a portion of the inner tube; -
Fig. 5a to Fig. 5c show cross sectional views of the internal heat exchanger according to the first embodiment, illustrating exemplary alternative profiles for the internal heat exchanger inner tube; -
Fig. 6 is a schematic illustration of the flow of refrigerant in the internal heat exchanger of the first embodiment; -
Fig. 7 shows part of an image ofFig. 4 , showing how parameters of the inner tube may be varied to achieve different performance characteristics of the internal heat exchanger of the first embodiment; - Referring now to the drawings, several embodiments of the present invention are shown in detail. The drawings are not necessarily to scale and certain features may be exaggerated to better illustrate and explain the present invention. Further, the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the invention to the precise configurations shown in the drawings and disclosed in the following detailed description.
- Referring to
FIG. 1 anair conditioning system 1 suitable for use in a motor vehicle is schematically illustrated. Theair conditioning system 1 includes acompressor 2, which may be driven, for example, by the engine of the vehicle or by a separate electric motor or the like. Thecompressor 2 has aninlet 4, connected to alow pressure line 21, via which where thecompressor 2 takes in refrigerant, or coolant, at low pressure. Thecompressor 2 also has anoutlet 3, via which pressurized refrigerant is output, into ahigh pressure line 5. Thehigh pressure line 5 leads to acooling device 6 where the compressed and thus heated refrigerant is cooled and condensed. Therefore, thecooling device 6 is also referred to as a condenser. In this example, the refrigerant used is R-134a that works at low pressure. - At an
outlet 7 of the cooling device, the refrigerant is discharged to anotherhigh pressure line 8 that leads to a high-pressure inlet 9 of aninternal heat exchanger 11. Theinternal heat exchanger 11 has a high-pressure outlet 12 that is in turn connected to anexpansion valve 15 via ahigh pressure line 14. Theexpansion valve 15 relaxes the refrigerant that is introduced into anevaporator 16. The refrigerant evaporates in theevaporator 16 and, as a result, absorbs thermal energy from the environment; in this example, cooling the air supplied to the interior of the motor vehicle. The resultant refrigerant vapor is then transported from theevaporator 16, via a low-pressure line 17, to the low-pressure inlet 18 of theinternal heat exchanger 11. This refrigerant vapor flows through theinternal heat exchanger 11 in a counter-current direction to the refrigerant that is being fed through the high-pressure inlet 9. In so doing, the refrigerant vapor cools the pressurized refrigerant, thus itself becoming heated. The refrigerant vapor is discharged, having been heated, at the low-pressure outlet 19 of theinternal heat exchanger 11. It is then conducted, via a low-pressure line 21, to theinlet 4 of thecompressor 2. - The
internal heat exchanger 11 allows the temperature of the refrigerant flowing to thecompressor 2 to be increased, which in turn increases the temperature of the refrigerant at theoutlet 3 of the compressor. Therefore, thecooling device 6 releases a greater amount of thermal energy. At the same time, theinternal heat exchanger 11 lowers the temperature of the refrigerant fed to theevaporator 16, thus providing an improved heat transfer between the evaporator 16 and ambient air. In this manner, theinternal heat exchanger 11 may be used to increase the efficiency of the air conditioning system. -
Fig. 2 shows a further schematic illustration of theinternal heat exchanger 11. In this example, it is shown as a U-shaped bent pipe 22. It will be appreciated that the exact shape of the heat exchanger will depend upon its application. However, in certain applications, but not all, bending of theheat exchanger 11 is required. Where it is required, the coaxial tube should be able to be bent sufficiently without causing the fluid flow channels or conduits to collapse or break. The bent pipe 22 has twolegs 23, 24, that are bent away from each other at their upper ends. - The high-pressure inlet 9 and the high-
pressure outlet 12 are in fluid connection with the remainder of thesystem 1 atposition 26a. The low-pressure inlet 18 and the low-pressure outlet 19 of theinternal heat exchanger 11 are in fluid connection with the remainder of thesystem 1 atposition 26b. As can be seen from the figure, positions 26a and 26b are located at or relatively close to the terminations of at the upper ends of the bent pipe 22. - Referring now to
Figs. 3a-3d , the structure of theinternal heat exchanger 11 will be described in more detail.Fig. 3a shows a perspective view of theinternal heat exchanger 11 of a first embodiment in its assembled state but prior to being bent into its final U-shaped configuration. As can be seen from the figure, theinternal heat exchanger 11 includes anouter tube 30, andinner tube 32, of whichend portions outer tube 30 andinner tube 32 being designed as refrigerant conduits. Theinner tube 32 is located inside and runs the entire length of theouter tube 30. The internal and external diameters of theouter tube 30 are 18mm and 20mm, respectively. The internal and external diameters of the parts of theinner tube 32 that extend beyond theouter tube 30 and can be seen in the figure are 12mm and 15mm, respectively. It will be understood that the dimensions of theouter tube 30 andinner tube 32 are selected for a given application and will therefore change in dependence upon application. The inner diameter of theouter tube 30 may from range 9-19mm for automotive or car applications, 20-39mm for bus applications and, 23-50mm for train applications. In one example having R-134a as the refrigerant, the outer tube is 24mm outer diameter with a 20mm inner diameter. The starting material, or base tube, for the inner tube is 18mm outer diameter with an inner diameter of 15mm. - Also shown in the figure are the high-pressure inlet 9 and the high-
pressure outlet 12 of theinternal heat exchanger 11. Each of these is connected to a suitable orifice in theouter tube 30 using a conventional process such as welding or brazing. The weld points are referenced 34 in the figure. In this manner, a fluid connection is formed between the high-pressure inlet 9 and the high-pressure outlet 12 via theouter tube 30. The connection orifices may be machined, or otherwise manufactured using any convenient process. In this manner, theouter tube 30 may be used as a connection sleeve which allows the system costs to be reduced. Theextreme end points 36 of theouter tube 30 are joined toinner tube 32 to ensure that the joint is effectively sealed against leakage of the refrigerant. Again a conventional process may be used; for example o-rings, crimping and or welding or brazing.Fig. 3b shows a photograph of an example of aninternal heat exchanger 11 similar to that shown inFig. 3a - In the figure the
inner tube 32 hasend portions pressure inlet 18 and the low-pressure outlet 19 of theinternal heat exchanger 11. In this example, theend portions portions low pressure tubes Fig. 1 . This in turn means that no suction side connection tubes are needed; thus obviating the need for costly connection processes, such as welding and eliminating the risk of refrigerant leakage at such connection points. - Between the
end portions inner tube 32 is acentral portion 32c that has been deformed into a helical shape along its longitudinal axis. A photograph of the exterior of a section of thedeformed portion 32c of the inner tube of theinternal heat exchanger 11 according to the first embodiment is shown inFig. 3c . Thecentral portion 32c may be deformed using any convenient deforming procedure. In the present example it is deformed through a repeated clamping process. However, other deforming processes or apparatus, such as a press or hammer, may be used. In this example, the clamping process is implemented using shaped opposing clamping surfaces to achieve the desired exterior profile of theportion 38b. Themarks 38a left in the outer surface of thedeformed portion 32c by the action of the clamping process may be seen inFig. 3c . Furthermore, it can be seen fromFig. 3c that thedeformed portion 32c has a helical profile. This helical profile can be more clearly seen from the schematic illustration of a section ofportion 32c illustrated inFig. 3d . - Referring to
Fig. 4 the method of manufacturing elliptical helix ofcentral portion 32c, according to this example, will now be described.Fig. 4 shows an image schematically illustrating a part of theinner tube 32, including part ofcentral portion 32c, arranged about itslongitudinal axis 42. As can be seen from the figure, theleft hand end 32a of theinner tube 32 is not deformed and is circular is cross section. Adjacent theleft hand end 32a end of theinner tube 32 isportion 44a that has been deformed to an approximate elliptical shape of predetermined dimensions. These dimensions may be controlled using the parameters of the deforming process; for example the linear extent of the clamping operation and the shape, dimensions and material properties of the clamping surfaces. - In the figure, the
major axis 46a of theelliptical portion 44a is shown orientated vertically. When the clamp is removed fromportion 44a of theinner tube 32, theinner tube 32 is advanced a fixed predetermined distance along itslongitudinal axis 42 to bring theportion 44b of the tube adjacent the clamping surfaces and theinner tube 32 is rotated by a fixed angle in a given direction about its longitudinal axis; in this example 45 degrees. The clamping operation is then repeated. This process is then repeated along the desired length ofcentral portion 32c of theinner tube 32, as is illustrated bydeformed portions 44b - 44f. In this manner an approximate helical structure of approximately fixed helical pitch and approximately constant elliptical cross section may be formed. With the exception of its helical form, thecentral portion 32c of theinner tube 32 is free or substantially free of projections and is relatively smooth in both its circumferential direction and its longitudinal direction. The inventors have found that this process of manufacture may be largely automated by using a bending machine set to zero bend radius. Thus, the creation of the helical structure of thecentral portion 32c of theinner tube 32 may be a relatively rapid and inexpensive process. - Once the
inner tube 32 is formed, it is assembled with theouter tube 30, by inserting theinner tube 32 inside theouter tube 30. The fit between theinner tube 32 and theouter tube 30 may be any convenient fit, such as a loose fit or a slight interference fit. Thus,inner tube 32 and theouter tube 30 may be assembled by hand or be automated. The welding or braising, including crimping if this is required, of theextreme end points 36 of theouter tube 30 toinner tube 32 may then be carried out. This may be done in the region where thenon-deformed end sections inner tube 32 transition into the adjacentdeformed portion 32c. -
Fig. 5c shows a cross sectional view, in the direction of arrows A-A shown inFig. 3a , of theinternal heat exchanger 11, and illustrates theinner tube 32 and theouter tube 30 once assembled. As can be seen from the figure, theinner tube 32 forms an approximate ellipse, the major axis of which is approximately equal to the internal diameter of theouter tube 30; i.e. 18mm. It will be understood that the cross sectional profile of theinner tube 32 could be varied either to meet heat exchange requirements or in order to meet manufacturing requirements. For example as an ellipse, as is illustrated inFig. 5a could be used. Other examples could include a triangular or quadrilateral shape, such as an approximate square as is illustrated inFig. 5b could also be used. Indeed, other cross sectional profiles may be contemplated, which have increased numbers of sides. - In this example shown in
Fig. 5c , theinner tube 32 contacts the inner surface ofouter tube 30 atpoints inner tube 32 and the inner surface ofouter tube 30 which run the entire length of the helical structure of thecentral portion 32c of theinner tube 32. In this manner, two refrigerantfluid flow channels inner tube 32 and the inner surface ofouter tube 30. Thefluid flow channels fluid flow channels fluid flow channel 50 lies on the inside of theinner tube 32. The third refrigerantfluid flow channel 50 carries refrigerant supplied to the suction side of the compressor. The three refrigerant fluid flow channels run substantially the entire length of the helical structure of thecentral portion 32c of theinner tube 32. - The third refrigerant
fluid flow channel 50 has a cross sectional area which is substantially equal to, or is only marginally reduced relative to the cross sectional area of the base circular tube from which it is formed, and from which the remainder of the suction side, low pressure lines of theair conditioning system 1, are made. This means that the pressure drop caused per unit length of thefluid flow channel 50 is substantially the same as, or not significantly increased relative to, that of the base circular tube from which it is formed, such aslow pressure line 21. By avoiding significant pressure loss on the suction side of theinternal heat exchanger 11, a considerable loss in the efficiency of theair conditioning system 1 may be avoided, especially in systems operating at lower pressures. - In addition, the inventors have surprisingly discovered that the creation of the helical structure of the
central portion 32c of theinner tube 32 does not cause a significant or measurable drop in pressure in thefluid flow channel 50 relative to a correspondingly profiled tube with no helical structure. The surprising lack of pressure drop in the suction side of theinternal heat exchanger 11 of the present embodiment may strongly contribute to the efficiency of theair conditioning system 1. - Whilst in applications for which the
internal heat exchanger 11 of the present embodiment is designed benefit from no significant drop per unit length in pressure in thefluid flow channel 50 relative to a correspondingly profiled tube with no helical structure, it will be appreciated that in other applications of the invention a greater pressure drop may be permitted. This may be for example, 2%, 5% or 7% increase relative to a correspondingly profiled tube with no helical structure. However, in some embodiments for certain applications, the suction side pressure drop per unit length of theinternal heat exchanger 11 may be up to 30% higher than that of the normal suction side line. In other embodiments this figure may be 10% or 20%. - It will be appreciated that in certain known heat exchangers, in which the design causes such a pressure drop, it may not be easy to remedy. One reason for this is that the technical characteristics of the low pressure fluid flow channel of the heat exchanger may not be easily changed to overcome this problem. For example, it may not be possible to change the cross sectional area of the channel due to space constraints or bending constraints. Additionally, this may not be possible due to the fact that manufacturing costs may be unduly increased due to increased operations being required. Furthermore, it may not be possible to change the internal geometry or flow characteristics of the low pressure fluid flow channel since this may adversely affect the heat exchanging characteristics of the device.
- As can be see from
Fig. 5c , the area across which heat may be exchanged betweenfluid flow channel 50 and each offluid flow channels inner tube 32. Moreover, due to the cross sectional shape of the refrigerantfluid flow channels flow channel 50 and each offluid flow channels fluid flow channels inner tube 32. This length of contact is illustrated, in the case offluid flow channels 52a byline 58 in the figure. It will be appreciated that this line of contact provides a convex heat transfer surface (the external surface of the inner tube 32) against which the fluid influid flow channels fluid flow channels -
Fig. 6 illustrates the flow of refrigerant in theinternal heat exchanger 11 according to the present embodiment. The refrigerant flowing in refrigerantfluid flow channel 50 is referenced 60 and the refrigerant flowing in refrigerantfluid flow channels fluid flow channels internal heat exchanger 11 and completes three complete cycles around the fluid influid flow channel 50. - It will be understood that the heat exchange characteristics required for a different applications will vary. Accordingly, the heat transfer surface of the present embodiment may be varied. Clearly, the exterior dimensions, such as length and diameter, of the internal heat exchanger may be varied where space permits. Where this is not possible or not desired, parameters of the
inner tube 32 may be varied as is illustrated inFig. 7. Fig. 7 illustrates part of the image ofFig. 4 illustrating severaldeformed portions 44 of theinner tube 32; where: - "a" = width of base form, determined by the height of the base form if the cross sectional area is equal to the base, or starting, material tube;
- "b" = height of base form:
- "c" = depth of the of base form along the longitudinal axis of the
inner tube 32 - "d" = distance between two deformations
- "e" = angle between symmetry axis of two deformations
- "f" = length of straight portion of the base form, which depends upon "a" and "b" and is zero if the form is elliptical.
- "c" = depth of the of base form along the longitudinal axis of the
- The heat transfer surface, the flow velocity and therefore the heat transfer may be adjusted by modifying the geometry of the
inner tube 32. The parameters "a", "b" and "f" determine the cross section of theliquid flow channels - (i) the efficiency of the
internal heat exchanger 11 may be increased by decreasing "c" and "e"; i.e. by increasing the number of deformations per unit length of theinner tube 32 and decreasing the slope of the helix; this may be in the range of 20 to 45 degrees for example; - (ii) the efficiency of the
internal heat exchanger 11 may be decreased by increasing "c" and "e"; i.e. by decreasing the number of deformations per unit length of theinner tube 32 and increasing the slope of the helix; this may be in the range of 45 to 90 degrees for example. - It will be appreciated that if the
internal heat exchanger 11 is to be formed as U-shaped pipe or other shape, theinternal heat exchanger 11 should have sufficient bending stability. The bending stability of theinternal heat exchanger 11 may be increased by decreasing the value of parameter "f'. - It will be understood that the above described embodiments give rise to certain advantages. The contours of the
inner tube 32 can be placed anywhere along, or even along only a part of, the length of theinner tube 32. Moreover, heat transfer may be adjusted by changing the geometry of the interface between theinner tube 32 and theouter tube 30, and this may be done without significantly changing the forming tool, such as a clamp, or process used. This provides considerable flexibility in terms or manufacturing. Heat exchanger applications with different performance criteria may be achieved without having to significantly modify the manufacturing process or tooling. As the inner tube may be made from standard tubing material, it is low cost. No expensive extrusions are required and no suction side connection tubes are needed, which may help to ensure that manufacturing is simplified and reliability of the system is increased. Bending flexibility may be adjusted by altering the geometry of the deformed tube. Theouter tube 30 may be used as a connection sleeve which further allows the system costs to be reduced. Despite the fact that that low-pressure channel may be particularly large, reducing the tendency for suction side pressure drop, a relatively small outside diameter may be achieved. - It will also be understood that various changes may be made to the above described embodiments. For example, whilst the internal heat exchangers of the embodiments have been described such that the high and low pressure fluid flows through the heat opposite directions, or "counter current", these embodiments could also be implemented using a "same direction" implementation. Furthermore, whilst the refrigerant used in the above described embodiments is R-134a, other refrigerants could equally be used. For example, other low pressure refrigerants or refrigerants that work at high pressures, such as carbon dioxide. Moreover, although the above described embodiments have been described in relation to automotive applications, it will be appreciated that the invention may be applied to a wide range of other applications. These may include for example, busses, lorries, trains and non-mobile applications. Additionally, whilst the above described embodiments have been described as utilizing base tube material that is circular in cross section, other cross sections could be used, such as elliptical cross sections.
- The preceding description has been presented only to illustrate and describe exemplary embodiments of the methods and systems of the present invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. It will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. The invention may be practiced otherwise than is specifically explained and illustrated without departing from its spirit or scope. The scope of the invention is limited solely by the following claims.
Claims (15)
- A heat exchanger comprising an outer conduit and an inner conduit, arranged inside of and along the longitudinal axis of the outer conduit, the inner conduit and the outer conduit being arranged to form a fluid flow channel between the inner surface of the outer conduit and the outer surface of the inner conduit, the fluid flow channel having a cross sectional form, in a plane substantially perpendicular to the longitudinal axis of the outer conduit, that is elongate being substantially greater in the circumferential direction of the outer conduit than in the radial direction of the outer conduit, characterized in that the inner conduit has a plurality of zones distributed along its axial length at which the inner conduit is locally deformed, each zone comprising (i) a region of decreased outer dimension of the inner conduit located at a first angular position in a plane substantially perpendicular its axial length, and (ii) a corresponding region of increased outer dimension of the inner conduit at a second angular position in a plane substantially perpendicular its axial length, the region of decreased outer dimension corresponding to the fluid flow channel and the region of increased outer dimension corresponding to a point of contact between the inner and the outer conduits, and that the fluid flow channel is arranged in a helical shape along the longitudinal axis of the outer conduit..
- A heat exchanger according to claim 1, wherein the inner conduit is deformed such that it has a cross sectional form, in a plane substantially perpendicular to the longitudinal axis of the outer conduit, that is substantially oval (non-circular ellipse), triangular or quadrilateral, providing respectively two, three or four fluid flow channels separated respectively by two, three or four points of contact between the outer conduit and the inner conduit.
- A heat exchanger according to claim 1 or 2, wherein the cross sectional form of the fluid flow channel is substantially crescent-shaped.
- A heat exchanger according any of claims 1 to 3, wherein the part of the outer surface of the inner conduit defining the fluid flow channel presents a substantially convex surface to the interior of the fluid flow channel.
- A heat exchanger according to any of claims 1 to 4, wherein the deformations are discrete deformations.
- A heat exchanger according any of claims 1 to 5, wherein the deformations are nonoverlapping.
- A heat exchanger according to any one of claims 1 to 5, wherein the deformations are continuous along the longitudinal axis of the inner conduit.
- A heat exchanger according to any of claims 1-7, wherein the inner refrigerant conduit, along the length of the outer refrigerant conduit, comprises a cross sectional area which is substantially equal to, or is only marginally reduced relative to an equivalent non-deformed conduit so that the pressure drop caused per unit length of the inner refrigerant conduit is substantially the same as, or not significantly increased relative to the pressure drop of the equivalent non-deformed conduit.
- A method of manufacturing a heat exchanger comprising an outer conduit and an inner conduit arranged inside of and along the longitudinal axis of the outer conduit, the method comprising:locally deforming the inner conduit at a plurality of positions distributed along its axial length, such that at each position the outer dimension of the inner conduit is reduced;assembling the deformed inner conduit with the outer conduit such that the inner conduit substantially forms at least two line contacts with the outer conduit and at least two substantially separate fluid flow channels between the inner surface of the outer conduit and the outer surface of the inner conduit, characterized by applying a deformation operation at the inner conduit such that at each position the outer dimension of the inner conduit is reduced at a first angular position in a plane substantially perpendicular its axial length, and the outer dimension of the inner conduit is increased at a second angular position in a plane substantially perpendicular its axial length, and progressively rotating the inner tube relative to the deforming operation as the inner conduit is deformed at the plurality of positions along its axial length, such that the fluid flow channel in the assembled heat exchanger follows a helical path along the longitudinal axis of the outer conduit..
- A method according to claim 9, wherein the deforming operation at each of the plurality of positions is a discrete operation, such as a clamping or an impact operation.
- A method according to claim 9, wherein the deforming operation at each of the plurality of positions is a continuous deforming process such as rolling.
- A method according to any one of claims 9 to 11, wherein the base conduit material is a tube of substantially circular cross section.
- A method according to any one of claims 9 to 12, wherein the deforming operation utilises one or more profiled deforming elements to provide the inner conduit with an oval, triangular or quadrilateral cross sectional profile.
- Method according to any of claims 9 to 13, wherein the helix shape of the inner refrigerant conduit is manufactured by fixing a tube with a given cross-sectional shape, preferably a circular shape, at a fixed angle in a given direction of the longitudinal axis of the tube; forming, preferably clamping or sledging, the fixed tube in order to create a local deformation of the tube, rotating the tube to another a fixed angle in a given direction of its longitudinal axis, preferably rotating the tube by steps of 45°, deforming the tube at a new position along the longitudinal axis with the new fixed angle, and repeating this step until the desired helix or spiral shape is created.
- Method according to any of claims 9 to 14, wherein the forming is automated by using a bending machine set to zero bend radius.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP10726891.4A EP2425193B1 (en) | 2009-04-30 | 2010-04-30 | Heat exchanger |
PL10726891T PL2425193T3 (en) | 2009-04-30 | 2010-04-30 | Heat exchanger |
SI201031564T SI2425193T1 (en) | 2009-04-30 | 2010-04-30 | Heat exchanger |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP09159260 | 2009-04-30 | ||
GBGB0909221.4A GB0909221D0 (en) | 2009-04-30 | 2009-05-29 | Heat exchanger |
PCT/EP2010/002656 WO2010124871A2 (en) | 2009-04-30 | 2010-04-30 | Heat exchanger |
EP10726891.4A EP2425193B1 (en) | 2009-04-30 | 2010-04-30 | Heat exchanger |
Publications (2)
Publication Number | Publication Date |
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EP2425193A2 EP2425193A2 (en) | 2012-03-07 |
EP2425193B1 true EP2425193B1 (en) | 2017-07-19 |
Family
ID=40902265
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP10726891.4A Active EP2425193B1 (en) | 2009-04-30 | 2010-04-30 | Heat exchanger |
Country Status (9)
Country | Link |
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US (1) | US20120097380A1 (en) |
EP (1) | EP2425193B1 (en) |
CN (1) | CN102460054B (en) |
ES (1) | ES2643324T3 (en) |
GB (1) | GB0909221D0 (en) |
HU (1) | HUE034718T2 (en) |
PL (1) | PL2425193T3 (en) |
SI (1) | SI2425193T1 (en) |
WO (1) | WO2010124871A2 (en) |
Families Citing this family (8)
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---|---|---|---|---|
DE102010034112A1 (en) * | 2010-08-12 | 2012-02-16 | Gm Global Technology Operations Llc (N.D.Ges.D. Staates Delaware) | Internal heat exchanger for a motor vehicle air conditioning system |
KR101600296B1 (en) * | 2010-08-18 | 2016-03-07 | 한온시스템 주식회사 | Double pipe heat exchanger and manufacturing method the same |
GB2523107A (en) * | 2014-02-12 | 2015-08-19 | Eaton Ind Ip Gmbh & Co Kg | Heat exchanger |
CN106574824B (en) * | 2014-07-25 | 2019-05-17 | 哈金森公司 | The heat exchanger for automotive air conditioning systems of such as internal exchanger and the system including the heat exchanger |
DE102014220403A1 (en) * | 2014-10-08 | 2016-04-14 | Mahle International Gmbh | Method for mounting a heat exchanger device and heat exchanger device |
EP3306248B1 (en) * | 2016-10-05 | 2019-03-06 | Hs R & A Co., Ltd. | Double pipe heat exchanger and method for manufacturing the same |
CN107449147B (en) * | 2017-09-25 | 2019-11-15 | 江苏来德福汽车部件有限公司 | A kind of Fryer heat exchanger |
CN112437860B (en) * | 2019-10-15 | 2022-01-11 | 安美(北京)汽车工程技术有限公司 | Refrigerant liquefier and refrigeration cycle device |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3730229A (en) * | 1971-03-11 | 1973-05-01 | Turbotec Inc | Tubing unit with helically corrugated tube and method for making same |
US4194560A (en) * | 1976-03-19 | 1980-03-25 | Nihon Radiator Co., Ltd. | Oil cooler and method for forming it |
JP2002318015A (en) * | 2001-04-17 | 2002-10-31 | Orion Mach Co Ltd | Freezer |
JP2004278854A (en) * | 2003-03-13 | 2004-10-07 | Toyo Radiator Co Ltd | Double-walled pipe heat exchanger and its manufacturing method |
US20040244958A1 (en) * | 2003-06-04 | 2004-12-09 | Roland Dilley | Multi-spiral upset heat exchanger tube |
US7011150B2 (en) * | 2004-04-20 | 2006-03-14 | Tokyo Radiator Mfg. Co., Ltd. | Tube structure of multitubular heat exchanger |
JP4350079B2 (en) * | 2004-11-09 | 2009-10-21 | 株式会社デンソー | Double tube, manufacturing method thereof, and refrigeration cycle apparatus including the same |
DE102005052974B4 (en) * | 2004-11-09 | 2013-03-21 | Denso Corporation | Double walled pipe |
US20080141665A1 (en) * | 2005-01-21 | 2008-06-19 | T. Rad Co., Ltd. | Double Pipe Heat Exchanger and Method of Manufacturing the Same |
JP3953074B2 (en) * | 2005-05-16 | 2007-08-01 | ダイキン工業株式会社 | Heat exchanger |
DE102006017816B4 (en) | 2006-04-13 | 2008-04-24 | Eaton Fluid Power Gmbh | Inner chiller heat exchanger |
-
2009
- 2009-05-29 GB GBGB0909221.4A patent/GB0909221D0/en not_active Ceased
-
2010
- 2010-04-30 PL PL10726891T patent/PL2425193T3/en unknown
- 2010-04-30 EP EP10726891.4A patent/EP2425193B1/en active Active
- 2010-04-30 WO PCT/EP2010/002656 patent/WO2010124871A2/en active Application Filing
- 2010-04-30 HU HUE10726891A patent/HUE034718T2/en unknown
- 2010-04-30 ES ES10726891.4T patent/ES2643324T3/en active Active
- 2010-04-30 CN CN201080027978.7A patent/CN102460054B/en not_active Ceased
- 2010-04-30 SI SI201031564T patent/SI2425193T1/en unknown
- 2010-04-30 US US13/318,040 patent/US20120097380A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
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EP2425193A2 (en) | 2012-03-07 |
HUE034718T2 (en) | 2018-02-28 |
GB0909221D0 (en) | 2009-07-15 |
US20120097380A1 (en) | 2012-04-26 |
WO2010124871A2 (en) | 2010-11-04 |
CN102460054B (en) | 2016-04-20 |
CN102460054A (en) | 2012-05-16 |
ES2643324T3 (en) | 2017-11-22 |
WO2010124871A3 (en) | 2011-02-17 |
SI2425193T1 (en) | 2018-02-28 |
PL2425193T3 (en) | 2018-01-31 |
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