EP2447626B1 - Heat exchanger, in particular for use with refrigerated cabinets - Google Patents

Description

The invention relates to a heat exchanger having a base profile made of metal, which is connected at its one end to an inlet device and at its other end to an outlet device for a refrigerant. Such a heat exchanger is used in particular for use in refrigerated cabinets, such as refrigerators, freezers, refrigerators and freezers.

Known heat exchanger devices for refrigeration cabinets typically have a serpentine curved conduit between an inlet for a refrigerant and the outlet for the refrigerant. Such pipelines have a circular cross-section hollow chamber and a comparatively small heat exchange surface for the heat exchange. This is expressed in a large hydraulic diameter. For the required heat exchange capacity large pipe lengths are necessary, which are associated with significant pressure losses between the inlet device and the outlet device for the refrigerant. This requires appropriately sized compressors, which increases energy consumption.

An improvement is achieved by using multi-chamber hollow profiles as the basic profile for the refrigerant line. In the German Offenlegungsschrift DE 10 2007 023 696 A1 such a refrigerant pipe consists of a serpentine shaped multi-chamber hollow profile. Due to the corresponding number of chambers, the wettable inner surface increases, thereby reducing the hydraulic diameter of such a refrigerant pipe. The hydraulic diameter (D _h = 4A / U) is the quotient of the fourfold flow cross section and the circumference wetted by the refrigerant. The smaller the value of the hydraulic diameter, the more energy efficient the heat exchanger. In order to achieve a sufficient temperature difference through such a heat exchanger, a comparatively long refrigerant pipe is required, or there are provided means for increasing the heat exchange, as known for example from heat exchangers for use in motor vehicle air conditioners, namely fins, which are arranged between the multi-chamber hollow profiles and at Multi-chamber hollow profiles made of aluminum material are connected via a brazed joint. Such fins increase the heat exchange surface, but make the heat exchanger more expensive due to the necessary solder connection.

From the patent US 4,298,062 is a heat exchanger of a serpentine-shaped multi-chamber hollow profile known, this multi-chamber hollow profile is provided to increase the heat exchange with protruding ribs. To further improve the heat exchange, it is proposed to enlarge the ribs.

The object of the present invention is to provide a heat exchanger, in particular for use in refrigerated cabinets, which has a high heat exchange capacity and is easy to produce.

This object is achieved with a heat exchanger having the features of claim 1. In the new heat exchanger according to the invention, at least one base profile made of metal, preferably of aluminum or an aluminum alloy, is present as the refrigerant line, which is arranged between an inlet device and an outlet device and connected to the respective devices. In known manner, the base profile may be a serpentine, serpentine or meandering conduit for the refrigerant between the inlet and outlet means, ie, starting from the inlet means Basic profile a first profile section where the refrigerant is transported in the main flow direction. At a reversal point, the refrigerant line is bent and the flow direction is changed. The refrigerant is transported further in a further second profile section counter to the main flow direction in order to be conducted again in the opposite direction, namely in the main flow direction, at the next reversal point. This is repeated until the refrigerant reaches the outlet. The refrigerant line formed by the base profile thus comprises first profile sections for flow of the refrigerant in the main flow direction and second profile sections for flow of the refrigerant against the main flow and between the first and second profile sections curved profile sections at the reversal points of the flow direction. This is comparable to prior art devices. In the heat exchanger according to the invention are also means for increasing the heat exchange with the surrounding air or with an additionally provided flowing in the cross-flow fluid, preferably a cooled air flow provided. However, this is not the known slats that need to be connected via a solder connection to the base profile, but the basic profile is deformed to increase the heat exchange itself and that the first and second profile sections. These profile sections are repeatedly deformed transversely to the main flow direction.

Such deformations may be Verwellungen of the profile, so that the profile of a reversal point to the opposite reversal point takes a wavy, preferably sinusoidal course. Another possibility is that the profile is formed around an axis extending in the main flow or countercurrent axis, ie is twisted, so that a spiral course results. Another possible deformation of the base profile is a twist, i. a rotation in the longitudinal axis of the profile.

The basic profile is an extruded flat multi-chamber hollow profile with two parallel broad sides and two arched narrow sides. According to the invention, adjacent strands of the respective profile sections of the base profiles and / or adjacent multi-chamber profile strands of a composite profile strand, which forms the base profile, each have differently oriented deformations. The extruded multi-chamber hollow profiles used have in cross-section a width between 5 mm and 32 mm, a height between 0.6 mm and 3 mm and a wall thickness between 0.1 mm and 0.5 mm. The number of chambers in such a multi-chamber hollow profile is between 0.5 chambers / mm width of the basic profile to 2 chambers / mm width of the base profile. The chambers of such a basic profile can, as in known multi-chamber hollow sections used for heat exchangers, have round, oval or polygonal cross sections. After extrusion and a possible desired coating of multi-chamber hollow profile strand is deformed, for example verwellt, twisted or twisted. This can be done, for example, sections of the profile strand, ie, provided for the heat exchanger first and second profile sections are formed and then bent at intended reversal points so that each subsequent profile sections come to lie next to each other or with each other. In the forming process, the chambers of the multi-chamber hollow profile are retained.

A preferred embodiment of a heat exchanger for refrigeration cabinets has profile sections of the basic profile with sinusoidal corrugations, i. the multi-chamber hollow profiles are bent by a forming process. The forming force presses from the top and bottom against the broad sides of the multi-chamber hollow profiles, so that there are sinusoidal Verwellungen the profile sections with elevations and depressions. The individual elevations and depressions can be generated successively on a profile section or simultaneously, depending on the forming device used.

If a corrugated profile section in the main flow direction is subsequently also curved by a profile section which transports the refrigerant counter to the main flow direction, then it is preferred for elevations and depressions of the aforementioned profile sections to be provided in such a way that in the heat exchanger in each case an elevation of a first Profile section adjacent to a recess of a second profile section lies. In this way, a particularly good heat exchange performance, for example achieved with the ambient air or a cross-flow airflow.

In a further preferred embodiment, a compact heat exchanger can also be produced by using a plurality of base profiles, each basic profile having deformed first and second profile sections, ie corrugated, twisted or twisted profile sections. Each individual basic profile has a refrigerant line that lies in one plane and, as it were, results in one layer. Several basic profiles in the heat exchanger then mean several layers, each basic profile is preferably connected to the same inlet and outlet device. Such an inlet or outlet device may preferably be an extruded profile piece of aluminum material, which has corresponding recesses corresponding to the number of basic profiles provided in the heat exchanger. A connection of the ends of the base profiles with the inlet or outlet device can be made in a simple manner by flame brazing, but also by other known connection options. The aforementioned multiple layers in the heat exchanger are preferably separated from one another by separating plates as in known applications in refrigerated cabinets. Such partition plates may be made of plastic or of an aluminum alloy. When the partition plate may be a plastic plate, a smooth sheet or punched perforated plate, a grid or an expanded metal parting plate. The connection of the base profiles with the partition plates is effected by a positive and / or non-positive and / or material connection, in the simplest way by a mechanical clamping. There are also solder joints possible. The advantage of the heat exchanger according to the invention, however, is that by the deformations in the simplest way, clamping is possible and can be dispensed with a solder joint and thus a relatively expensive process step. If heat exchangers have a plurality of basic profiles, ie several layers of deformed basic profiles arranged one above the other, then the overall height of the deformed basic profile is selected to be between 3 mm and 50 mm.

The advantage of the heat exchanger according to the invention is that it has a very small hydraulic diameter. Because of this, less refrigerant is needed. The refrigerators can use smaller compressors that are quieter and require less energy. Another advantage is the material-uniform simple construction, consisting of extruded base profiles and optionally extruded inlet devices and outlet devices, which could be connected to one another in a simple manner by flame brazing. An expensive solder coating for a braze joint, such as for the connection of fins and multi-chamber hollow profiles known from the prior art, is not necessary for the basic profiles.

The choice of aluminum alloy, namely 1XXX, 3XXX, 5XXX, 6XXX alloys, in particular A1MgSi or A1Mg alloys, depends on the desired strength and corrosion resistance of the heat exchanger, ie on its intended use. The heat exchanger according to the invention can also be used advantageously for other applications than for refrigerated cabinets.

To further improve the heat exchange projecting ribs may be provided on the outer surfaces of the base profile, as in multi-chamber hollow sections for automotive heat exchangers. Another possibility is dependent on the configuration of the deformation at the first and second profile sections. Thus, if gaps between the first and second profile sections are present, inserted into these spaces in addition turbulators.

Fig. 1

eine perspektivische Ansicht eines erfindungsgemäßen Wärmetauschers;

Fig.2a

einen verwellten Profilabschnitt;

Fig.2b

einen verdrillten Profilabschnitt;

Fig.2c

einen verdrehten Profilabschnitt;

Fig.3

einen weiteren erfindungsgemäßen Wärmetauscher in der Draufsicht;

Fig.4

einen Querschnitt durch ein Grundprofil gemäß Fig. 3 und

Fig.5.

einen weiteren Querschnitt durch ein Grundprofil gemäß Fig. 3.

The invention will be explained in more detail by exemplary embodiments in the drawings. Show it:

Fig. 1

a perspective view of a heat exchanger according to the invention;

2a

a corrugated profile section;

2b

a twisted profile section;

Figure 2c

a twisted profile section;

Figure 3

another heat exchanger according to the invention in plan view;

Figure 4

a cross section through a basic profile according to Fig. 3 and

Figure 5.

a further cross section through a basic profile according to Fig. 3 ,

The Fig.1 shows a heat exchanger according to the invention for use in refrigerated cabinets. This comprises two basic profiles, namely the basic profile 10 and the base profile 10 '. Both basic profiles 10, 10 'are connected at one end 11 to an inlet device 21 and at the other end 12 to an outlet device 22 for a refrigerant. Butane or carbon dioxide is used in particular as refrigerant for refrigerated cabinets. The inlet device 21 and the outlet device 22 are extruded profile pieces made of an aluminum alloy, in particular an A1Mg alloy. The inlet device 21 and the outlet device 22 each have two recesses whose cross section is adapted to the ends 11 and 12 of the base profiles 10, 10 ', which are inserted into the inlet device 21 and into the outlet device 22 and are connected by flame brazing with these.

The basic profiles 10, 10 'are extruded multi-chamber hollow profiles made from an AlMgSi alloy. The extruded multi-chamber hollow profile strands were verwellt in a deformation process. A portion of such a basic profile 10 with Verwellungen 30 is in the 2a shown. The base profile 10 is a multi-chamber hollow profile with a plurality of chambers 19, which increase the wettable inner surface for the refrigerant. The Verwellungen 30 lead to a sinusoidal profile of the base profile 10 with elevations 31 and recesses 32. As better Fig. 1 can be seen, the base profile 10, 10 'has different profile sections, namely profile sections which connect the base profile with the inlet device 21 and the outlet device 22 and profile sections 13 which transport the refrigerant in the main flow direction 60 to a reversal point 17, where the base profile 10, 10 'is bent over to a profile section 15 and the subsequent profile section 14 transports the refrigerant in a direction opposite to the main flow direction 60. This profile section 14 has Verwellungen 30. The Verwellungen 30 end in the area of the reversal point 18, where the curved profile section 16 is located. The profile sections 15, 16 are bent so that the first profile sections 13 and the second profile sections 14 are arranged side by side. Considering the first profile sections 13, which transport the refrigerant in the main flow direction 60 with the shape of the profile sections 14, which transport the refrigerant in the opposite direction, it becomes clear that the elevations 31 of the first profile sections 13 are adjacent to depressions 32 of the second profile sections 14 or the depressions 32 of the profile sections 13 adjacent to the elevations 31 of the profile sections 14, so that between these elevations 31 and depressions 32 spaces 33 result, through which a transverse air flow can be deflected and swirled. These spaces 33 can be further used to introduce so-called turbulators, which cause additional turbulence of the transverse air flow or the ambient air. Both basic profiles 10, 10 'are provided in a similar manner with Verwellungen 30, ie, the basic profile 10' has verwellt profile sections with elevations 31 'and recesses 32'.

For better stability of the heat exchanger, a separating plate 80 is provided between the one layer with the deformed base profile 10 and the other layer with the deformed base profile 10 ', in this case an aluminum sheet. The connection between the base profiles 10, 10 'and the separating plate 80 is effected by a clamping, which is not shown in this example. The partition plate 80 may additionally have perforations, punched out. This reduces the weight of the heat exchanger and leads to additional turbulence of the transverse air flow. On such a partition plate 80 heating wires can be arranged for a de-icing. For smaller heat exchangers can be dispensed with the separating plate, since by the deformation 30 of the basic profiles 10, 10 'are relatively stable units.

The base profiles 10, 10 'are coated with a bactericide and fungicide when used for refrigerated cabinets. Such a coating can, similar to a known solder or zinc coating, take place after the extrusion of the multi-chamber hollow profiles.

This in 2a shown multi-chamber hollow profile, which is extruded as a flat profile is provided with a Verwellung 30 can be twisted after extrusion in the longitudinal direction of the profile. 2b shows a profile section of such a basic profile 10 'with a twist 40. Another way of deformation shows Figure 2c , Here, a profile section of a basic profile 10 "is shown, which is bent around an axis, for example an axis running in the main flow direction 60. This results in spiral profiles 50. All three basic profiles 10, 10 ', 10" are originally flat multi-chamber hollow profiles which receive warps 30, twists 40 or twists 50 through a deformation process. Such a deformation is preferably carried out for the first profile section 13 in the main flow direction 60 and second profile sections 14 in the counterflow direction. At the reversal points 17, 18 bent profile sections 15, 16 are provided. In all basic profiles 10, 10 ', 10 "changed by the deformation of Cross-section of the profile, ie, despite the deformations, there are no restrictions or other cross-sectional reductions, which could lead to pressure losses of the refrigerant. The basic profiles 10, 10 ', 10 "have a small hydraulic diameter and a good heat exchange performance with the ambient air or a cross-flowed fluid, without additional fins are provided.

A further advantageous embodiment of a heat exchanger according to the invention shows Figure 3 , Here, a heat exchanger is schematically shown, which consists of a base profile 10 which is connected at one end 11 with an inlet device 21 and at the other end 12 with an outlet device 22. The base profile 10 is also a multi-chamber hollow profile, but composite profile. The basic profile 10 is in cross section in Figure 4 shown. It consists of three strands 1, 2, 3, which are connected to each other via a compound 4. The composite sites 4 extend in the longitudinal direction of the composite profile in each case between the strands 1 and 2 or 2 and 3 or other strands. In this embodiment, the composite profile has a width B of 18 mm, a height H of 1.7 mm and a wall thickness D of 0.35 mm. Each strand 1, 2, 3 has four chambers 19. The width of these chambers is 1.05 mm, the wall thickness of the compound 4 is 0.1 mm. For use in refrigeration furniture varies the width B of the base profile 10 after extrusion between 5 mm and 32 mm, the height H of the base profile 10 between 0.6 mm and 3 mm and the wall thickness D of the base profile 10 between 0.1 mm and 0 , 5 mm. In a basic profile 10, widths B of the basic profile 10 are provided between 0.5 and 2 chambers per millimeter. The in Figure 4 shown cross-section corresponds to the cross section of the base profile 10 in the heat exchanger in the region of the ends 11, 12 and in the region of the reversal points 17, 18, ie the curved profile sections 15 in the region of the reversal point 17 and the curved profile sections 16 in the region of the reversal point 18. Starting from the One end 11 of the basic profile 10 is followed by a corrugated profile section 13, in which the refrigerant is transported substantially in the main flow direction 60. Before the reversal point 17 end the Verwellungen 30 and the profile section 13 goes into the profile section 15 via. The composite profile is bent over to subsequently transport the refrigerant in the profile section 14 counter to the main flow direction 60 back to the reversal point 18. The profile section 14 has comparable Verwellungen 30 as the profile section 13, which is above and below then again below the profile section 14. At the reversal point 18 follows the curved profile section 16, where the flow direction is changed again. This profile section 16 has, comparable to the profile section 15, no Verwellungen. Up to the end 12 of the basic profile 10, the first profile sections 13, which transport the refrigerant in the main flow direction 60, repeat the profile sections 15 which reverse the flow direction of the refrigerant by a deflection of the base profile 10, so that in second profile sections 14 the refrigerant is opposite to the main flow direction 60 is passed to the other side of the heat exchanger to change there again in a profile section 16, the flow direction.

Over a substantial part of its longitudinal extent of the profile section 13 and profile section 14 is deformed. By forming operations, such as force from above or from below onto the base profile 10, the strands 1, 2, 3 still connected after extrusion are separated from one another in the region of the very thin composite sites 4. The warps 30 are different in this example for the strands 1, 2 and 3. The strand 1 extends from the end 11 initially undeformed, the strand 2 is curved by a forming force up to an increase 31 and the extruded profile 3 by forming force from top to bottom bent to a recess 32. A cross section is best Figure 5 to see where the profile section 13 is shown, in the same way it could also be a grooved profile section 14. It becomes clear that these are separate strands 1, 2, 3. The strands 1, 2, 3 have comparable waveforms in terms of amplitude and wavelength, but the waveforms are offset from each other, namely as out Figure 3 can be seen, the Verwellungen 30 are such that the staggered wave crests and troughs of the three corrugated strands 1, 2, 3 of the profile sections 13, 14 of the give a basic profile 10 as good as possible turbulence of a cross-flow air stream, comparable to turbulence in heat exchangers of the prior art consisting of multi-chamber hollow sections with soldered lamellae.

In the present invention is dispensed with the slats. The configured as a multi-chamber hollow profile base profile 10 thus takes on two tasks, it is namely refrigerant pipe and slat at the same time. The production of such a heat exchanger is relatively inexpensive, as can be dispensed with a Lotbeschichtung in the multi-chamber hollow sections and a brazing between lamellae and the refrigerant leading multi-chamber hollow sections.

LIST OF REFERENCE NUMBERS

1

strand

2

strand

3

strand

4

Verbund site

10, 10 ', 10 "

basic profile

11

End of 10

12

End of 10

13

profile section

14

profile section

15

profile section

16

profile section

17

reversal point

18

reversal point

19

chamber

21

intake means

22

outlet

30

corrugation

31.31 '

increase

32, 32 '

deepening

33

gap

40

twist

50

twisting

60

main direction

80

separating plate

B

Width of 10

D

Wall thickness of 10

H

Height of 10

Claims (13)

1. A heat exchanger, in particular for use with refrigerated cabinets, including an inlet facility (21) and outlet facility (22) for a refrigerant and a minimum of one extruded multi-chamber hollow profile made from metal as base section (10, 10', 10"), that is connected at one of its ends (11) to the inlet facility (21) and to the outlet facility (22) at its other end (12),
   whereby, the base section (10, 10', 10") has differently aligned sections of profile (13, 14, 15, 16), namely a minimum of first sections of profile (13) for flow of the refrigerant in the main direction of flow (50), as well as second sections of profile (14) for flow of the refrigerant opposite to the main direction of flow (50), as well as curved sections of profile (15, 16) at the deflection positions (17, 18) of the direction of flow between the first and second sections of profile (13, 14) so that a serpentine- shaped line is formed for the refrigerant between the inlet facility (21) and the outlet facility (22),
   whereby, the base section (10, 10', 10") features an agent to increase the heat exchange of the immediate ambient air of the base profile (10, 10', 10") and/or with a fluid transversely flowing past in the base section (10, 10', 10"), whereby, the agent used to increase the heat exchange for the first and second sections of profile (13, 14) of the base section (10, 10', 10") between the deflection positions (17, 18) has multiple deformations transverse to the main direction of flow (50) and features no lamellae,
   characterized in that adjacent extrusions of the respective sections of profile (13, 14) of the base sections (10, 10', 10") and/or adjacent multiple-chamber profile extrusions (1, 2, 3) of a composite profile row, which forms the base section (10, 10', 10"), each has differently aligned deformations.
2. A heat exchanger in accordance with claim 1, characterized in that the base section (10, 10', 10") of an extruded and deformed multi-chamber hollow profile is made from aluminium or an aluminium alloy.
3. A heat exchanger in accordance with claim 1 or 2, characterized in that the chambers (19) have a rounded, oval or polygonal cornered cross-section.
4. A heat exchanger in accordance with one of the claims 1 to 3, characterized in that the deformations of the base section (10, 10', 10") illustrates undulations (30) or transpositions (40) or twists (50) of the sections of profile (13, 14).
5. A heat exchanger in accordance with one of the claims 1 to 4, characterized in that the first and second sections of profile (13, 14) of the base section (10) have undulations (30) with peaks (31) and depressions (32) in the form of a sinus and, whereby, the base section (10) is curved at the deflection positions (17, 18) so that the sections of profile (13, 14) form rows adjacent to, or below each other.
6. A heat exchanger in accordance with claim 5, characterized in that the rows of the sections of profile (13, 14) adjacent to each other have peaks (31) of the first sections of profile (13) arranged adjacent to depressions (32) of the second sections of profile (14) and,
   whereby, the base section (10) features a cross-section of width (B) of between 5 mm and 32 mm and a height (H) of between 0.6 mm and 3 mm,
   whereby, the base section (10) features a wall thickness (D) of between 0.1 mm and 0.5 mm,
   whereby, the number of chambers (19) is between 0.5/mm to 2/mm for each 1 millimeter of the width (B) of the base profile (10).
7. A heat exchanger in accordance with claim 5 or 6, characterized in that multiple base sections (10) are each arranged in a position adjacent to sections of profile (13, 14) between the inlet facility (21) and the outlet facility (22).
8. A heat exchanger in accordance with one of the claims 5 to 7, characterized in that additional turbulators are provided that are inserted at the side of an intermediate chamber (33) between peaks (31) and depressions (32) of the sections of profile (13, 14).
9. A heat exchanger in accordance with claim 7 or 8, characterized in that the multiple layers of the sections of profile (10) are separated by separating plates (80) that are made from plastic or aluminium alloy, whereby, connection of the base section (10) to the separating plates is carried out by positive locking and/or forced locking and/or material locking connection, preferably by mechanical clamping.
10. A heat exchanger in accordance with one of the claims 1 to 9, characterized in that the overall height of the deformed section of profile (10, 10', 10") is between 0.3 mm and 50 mm.
11. A heat exchanger in accordance with one of the claims 1 to 10, characterized in that ribs are also formed on the outside of the base section (10, 10', 10").
12. A heat exchanger in accordance with one of the claims 1 to 9, characterized in that the inlet facility (21) and the outlet facility (22) are made from extruded sections of aluminium alloy profile.
13. A heat exchanger in accordance with one of the claims 1 to 10 characterized in that the surface of the base section (10, 10', 10") is coated with a bactericide and/or fungicide.

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