DE102023004600A1 - Cross-flow heat exchanger - Google Patents

Abstract

1. Cross-flow heat exchanger in plate and strip design
2. Cross-flow heat exchanger in plate and strip construction, consisting of a plurality of individual components (12, 14, 16) which form a stack (10) with each other, with at least
- a first component (12) which allows fluid passage of a medium in one direction,
- a second component (14) which allows fluid passage of this or another medium in a further direction,
- a third component (16) arranged between the first (12) and the second (14) component to form a firm bond between them, and
- fluid-conducting channels (18) which extend at least partially through the stack assembly (10) at the end and of which at least one channel section (20) serves to supply and another channel section (20) to remove the medium for the first component (12).

Description

The invention relates to a cross-flow heat exchanger in plate and strip construction, consisting of a plurality of individual components which form a stacked assembly.

A cross-flow heat exchanger directs the material flows in such a way that their directions intersect. These heat exchangers are essentially something between a countercurrent and a cocurrent heat exchanger. Cross-flow heat exchangers, for example, can be used to heat a fluid flow to a specific, fixed temperature.

Heat exchangers of this type, also called finned coolers, are state of the art, compare DE 20 208 748 U1 . With air as the cooling medium, such heat exchangers are often used to cool hydraulic fluids for the working hydraulics of mechanical systems such as construction machinery or the like, for hydrostatic travel drives or as oil coolers for heavily loaded gearboxes, particularly in wind turbines. During operation of such systems, the heat exchangers are not only exposed to mechanical loads, but also to a particularly high degree of thermal loads due to the high operating temperature of the fluids to be cooled. This is particularly the case when intermittent operating modes result in individual temperature jumps, which, due to material expansion, lead to severe stresses in the package of components that are usually joined to form a rigid block by soldering. The result is stress cracks, particularly in the area of the solder joints, with the risk of failure of the heat exchanger and thus a threat to the associated connected system.

In order to effectively counteract such stress cracks, DE 10 2010 046 913 A1 A cross-flow heat exchanger has already been proposed, in particular for fluid cooling devices, with a package of plane-parallel plates, wherein flow areas for a hot medium and for a cooling medium are formed alternately between pairs of superimposed plates, which are each laterally delimited by profile strips which keep the plates at a distance and which form soldering surfaces adjacent to the plates, wherein the profile strips extend at the flow areas of one medium and the other medium along edges of the plates which abut one another at an angle, and wherein at least the profile strips of the flow areas of the cooling medium have a base body, two legs extending from this along the soldering surfaces and between these a recess which is open to the adjacent flow area and which is delimited by flat wall parts at least in the area adjacent to its inner end section. Because this known solution features flat wall sections starting from the inner end portion of the recess, an at least approximately linear change in flexural strength can be achieved over the length of the profile legs. By selecting the length and/or inclination of these flat wall sections relative to the soldering surface plane, optimal bending behavior of the legs is achieved. In addition to stress cracks due to thermal stress, the service life is determined by changing operating pressures.

In order to supply the stacked assembly with the medium to be cooled, box-shaped chambers are soldered on from the outside. These serve as inflow and outflow chambers for the flowable medium, usually in the form of hydraulic oil to be cooled from a hydraulic circuit connected to the heat exchanger. An inflow chamber and an outflow chamber for the stacked assembly of a cross-flow heat exchanger are provided in DE 102 30 042 A1 shown.

Based on this prior art, the invention is based on the object of improving known heat exchangers, in particular enabling cost-effective production. This object is achieved by a cross-flow heat exchanger having the features of patent claim 1 in its entirety.

• - einer ersten Komponente, die einen Fluiddurchlass eines Mediums in einer Richtung ermöglicht,
• - einer zweiten Komponente, die einen Fluiddurchlass dieses oder eines anderen Mediums in einer weiteren Richtung ermöglicht,
• - einer dritten Komponente, die zwischen der ersten und der zweiten Komponente angeordnet einen festen Verbund zwischen diesen herstellt, und
• - fluidführenden Kanälen, die zumindest abschnittsweise den Stapelverbund endseitig durchgreifen und von denen zumindest ein Kanalabschnitt der Zufuhr und ein anderer Kanalabschnitt der Abfuhr des Mediums für die erste Komponente dient.

The cross-flow heat exchanger according to the invention consists of a plurality of individual components which form a stacked assembly with each other, with at least

• - a first component which allows fluid passage of a medium in one direction,
• - a second component that allows fluid passage of this or another medium in a further direction,
• - a third component arranged between the first and second components to form a firm bond between them, and
• - fluid-carrying channels which at least partially pass through the stack assembly at the end and of which at least one channel section serves to supply and another channel section to remove the medium for the first component.

Due to the fact that the fluid-carrying channels mentioned are essentially an integral part of the stacked assembly, formed from the individual components, they do not need to be designed from the outside as inlet or outlet chambers, placed laterally onto the stacked assembly and firmly connected to it, in particular soldered or welded, as shown in the prior art, which significantly simplifies the manufacture of the heat exchanger and helps to save manufacturing costs. Furthermore, the free cross sections of the fluid-carrying channels can be reduced within the internal guide, so that flow losses during operation, in particular due to turbulence, within the media flow are avoided. Since the cross-flow heat exchanger according to the invention also requires fewer soldering points or soldering surfaces for its construction due to the integral fluid guide, the associated thermal input is correspondingly reduced, so that the introduction of excessive thermal stresses is avoided and thus the risk of stress cracks occurring within the soldered connections of the rigid heat exchanger block is effectively counteracted. In this way, long-term operation of the cross-flow heat exchanger according to the invention is enabled.

The components mentioned in the stack can be designed as identical parts, which benefits functional reliability. The components can also be designed as identical parts in the form of a modular system, so that heat exchangers of different sizes can be constructed and implemented cost-effectively using only a few, differently sized components. It goes without saying that in a larger stack sequence, the third component is arranged alternately between the first and second components and subsequently between the second and first components, and so on. In the stack sequence, a third component is therefore always incorporated on the top and bottom of a first or second component.

In a preferred embodiment of the cross-flow heat exchanger according to the invention, the first component is enclosed on the outer circumference by a frame whose overall height corresponds to the overall height of at least one flow guide channel which extends in a fluid-conducting manner between two channel sections adjacent to it, which are at least partially enclosed by this edge. The frame can be formed as a single piece, for example as a stamped part, or the frame can be composed of individual strip-shaped frame parts which are available in different lengths for constructing different heat exchanger sizes, which benefits the basic concept of the heat exchanger as a modular system. The strip-shaped frame parts are preferably adjacent to one another in a horizontal installation position such that a corner region is left free in each case, wherein the components adjacent to the frame parts in the stack preferably have a contour recess following the respective corner region. The corner areas left free in this way can serve as assembly aids for mounting rods, creating a kind of box-shaped auxiliary assembly frame. Loaded with the components in a predefined sequence from the free top side, the stacked assembly then forms a rigid connection between the components through appropriate heat input, thus forming the entire block-like heat exchanger. Independently of this, it is also possible to use the left-free corner areas in the stacked assembly for the insertion of a weld seam, thus creating the stacked assembly as a heat exchanger block.

In any case, it is advantageous if the third component is formed from a flat plate with recesses at the ends the size of the adjacent channel sections and is coated with solderable materials. Thermal heat input then melts the solder of the plate, which is applied flatly on both opposite sides, forming strong connections with the adjacent components and forming the stacked assembly.

In a further preferred embodiment of the cross-flow heat exchanger according to the invention, the components arranged at the top and bottom in the stacking sequence are each formed from a flat end plate, at least one of which has the inlet and/or outlet for one medium, which is formed from a separate connecting piece that is placed on one side of the end plate and firmly connected to it. In this way, the connecting pieces can also be standardized and attached or soldered to the end plates of the stack as additional components.

In a preferred embodiment of the cross-flow heat exchanger according to the invention, the free cross-sections for the individual channel sections are rectangular, preferably square. These channel sections can be manufactured simply and cost-effectively and, due to their direct integration into the stacked assembly, require little installation space, which benefits a space-saving design of the heat exchanger.

In a further preferred embodiment of the cross-flow heat exchanger according to the invention When using multiple flow guide channels for one medium, each of these is formed from a longitudinal channel extending from a channel section at one end to the opposite channel section at the other end. This achieves maximum heat transfer between the media guide of one component and the second component, which are preferably separated from each other in a media-tight manner by the heat-conducting third, plate-like component.

To improve heat transfer in this regard, the second component is provided with at least one baffle, which, through its shape, both increases the heat transfer surface and controls the flow for better heat transfer. A typical design is corrugated in a zigzag pattern. The baffle opens into the open air at the free end faces of the heat exchanger and runs transversely or crosswise to the longitudinal channels of the respective first components. The baffle of the second component serves in particular to guide the flow of air, which is preferably passed through by a motor-driven fan at high flow velocity.

In addition to cooling hydraulic oil, it is also possible to cool water-glycol mixtures or other liquids and gases, such as water as an operating medium or charge air of a compressor.

Overall, the cross-flow heat exchanger according to the invention creates a structure that essentially allows the production of a plate and strip-based cross-flow heat exchanger as a whole with only a single soldering process, which has no equivalent in the prior art.

• 1 eine perspektivische Teilansicht auf einen hälftigen Wärmetauscher gemäß einem ersten Ausführungsbespiel;
• 2 in der Art eine Explosionszeichnung, eine der 1 entsprechende Ansicht auf Komponenten des Wärmetauschers;
• 3 in der Art eine Explosionszeichnung, eine perspektivische Seitenansicht auf ein weiteres Ausführungsbeispiel eines Kreuzstromwärmetauschers mit Fluidführung gemäß Pfeildarstellung;
• 4 eine Draufsicht auf eine Komponente des Wärmetauschers nach der 3 in Form einer Wärmetauscherplatte; und
• 5 in perspektivischer Seitenansicht den aus den Komponenten nach den 3 und 4 zusammengesetzten Wärmetauscher als Ganzes.

In the following, the cross-flow heat exchanger according to the invention is explained in more detail using two exemplary embodiments according to the drawing. In a schematic representation and not to scale, the

• 1 a perspective partial view of a half heat exchanger according to a first embodiment;
• 2 in the style of an exploded view, one of the 1 corresponding view of heat exchanger components;
• 3 in the manner of an exploded drawing, a perspective side view of a further embodiment of a cross-flow heat exchanger with fluid guidance according to the arrow representation;
• 4 a top view of a component of the heat exchanger after 3 in the form of a heat exchanger plate; and
• 5 in perspective side view the one made up of the components according to the 3 and 4 composite heat exchanger as a whole.

The cross-flow heat exchanger according to the invention consists of a plurality of individual components that form a stacked assembly, designated as a whole by 10, with first components 12 that enable fluid passage of a medium in a predeterminable direction. Furthermore, second components 14 are present, each of which enables fluid passage of this or another medium in a further predeterminable direction. Third components 16, which are arranged between the respective first component 12 and the second component 14, establish a solid assembly among the aforementioned components 12, 14, 16.

Furthermore, all components 12, 14, 16, as can be seen in particular from the 2 The stack assembly 10 has fluid-carrying channels 18 which extend through the stack assembly 10 at the ends, whereby the relevant channels 18 are only shown for the front half of the heat exchanger; a corresponding channel guide is also provided for the second half of the heat exchanger at the other end. In this respect, the front channel sections 20, formed from the front fluid-carrying channel 18, serve to supply the medium or fluid, and the other channel sections not shown serve to remove the medium at the other end of the heat exchanger. The fluid-carrying channels 18 have, according to the illustration according to the 2 a rectangular opening cross-section and in the stack assembly 10 the free channel sections 20 formed in this way are arranged one above the other in a media-carrying arrangement.

As can be seen from the 2 The first component 12 is enclosed on the outer circumference by a frame 22, the overall height of which corresponds to the overall height of a plurality of flow guide channels 24, which extend in a fluid-conducting manner between two channel sections 20 adjacent to said frame 22, which are at least partially enclosed by said frame 22. To form the individual flow guide channels 24, channel-like longitudinal guides 26 are introduced, which, spaced apart from one another, each accommodate a flow guide channel 24 between them. In this respect, the flow guide channels 24 run in a horizontal orientation and the hot medium supplied via the front channel 18, for example in the form of hydraulic medium, passes via the front channel section 20 of the first component 12, via the parallel running flow guide channels 24 to the rear channel section 20 (not shown in detail) and thus to the fluid-carrying channel 18, which then discharges the cooled medium in the form of hydraulic oil from the heat exchanger.

The frame 22 is in the embodiment according to the 1 and 2 composed of individual, strip-shaped frame parts 28, which leave a corner area 30 free when adjacent to one another. The components 14, 16 in the stack assembly 10 adjacent to the frame parts 28 also have a contour recess 32 following the respective corner area 30 in the manner of this corner area 30. As can be seen from the 1 The corner regions 30 and the subsequent contour recesses 32 arranged one above the other in the stacking sequence form an engagement possibility for a rod-like assembly aid, along which the individual components 12, 14, 16 can be stacked, or as in 1 As shown, if necessary, after removing or omitting the assembly aid, the exposed contours serve to create a weld seam 34 extending over the entire stacking sequence (see 1 ). Otherwise, the components 12, 14, 16 lying one above the other in the stacked assembly 10 are thermally treated in a corresponding assembly receptacle (not shown) and the soldering media arranged on both sides of the third component 16 as coating material bond to the respective component 14 lying above and a component 12 lying below, as shown in the 2 .

Instead of a plurality of flow guide channels 24, it is also possible to omit the rod-like longitudinal guides 26, resulting in free fluid passage from the front channel section 20 to the rear channel section 20 along a single flow channel across the entire cross-section defined by the frame 22. Each frame 22 consists of four strips 36 or longitudinal bars, the overall lengths of which are essentially freely definable and adapted to the size of the heat exchanger to be realized.

As further shown in the figures, the second component 14 has a preferably zigzag-shaped baffle 38, which opens into the open air at the free end faces of the heat exchanger and which, with its free, triangular opening cross-sections, runs transversely to the longitudinal channels 24 of the respective first component 12. The baffle 38 generally serves to guide the flow of cooling air; however, it is also conceivable to pass another gaseous or liquid cooling medium through it if necessary.

To complete the heat exchanger, it is further provided that the fourth component 40, arranged at the top and bottom in the stacking sequence, is each formed from a flat end plate, of which the upper one has the inlet and the lower one the outlet (not shown) for one medium, for example in the form of hydraulic medium. The respective inlet 42 or outlet 44 is formed from a separate cylindrical connecting piece 46, which is placed on one free side of the end plate and firmly connected to it via an annular weld seam 48. Instead of a weld seam 48, a soldered seam could also be provided, which is visually so inconspicuous that it would no longer be recognizable in the drawing. Thus, in the 3 When using soldered seam connections, the individual connection points are no longer recognizable. For attaching the corresponding connecting piece 46, a cylindrical through-opening 50 is provided in the plate-shaped fourth component 40, which is in fluid-conducting alignment with the underlying front channel section 20 of the second component 14. A solder layer is applied to the underside of the upper, fourth component 40 and to the top side of the lower, fourth component 40; when heated, this solder layer forms a connection with the underlying or overlying second component 14.

The second embodiment according to the 3 to 5 will only be explained insofar as it differs significantly from the preceding embodiment, whereby the same components are numbered with the same reference numerals and the statements made in this regard also apply to the modified embodiment.

When solving the 3 the first component 12 arranged above the second component 14 is closed at the bottom, with respect to its front channel section 20, by a closure plate 52, which is preferably a component of the third component 16, wherein the closure plate 52 in question then covers the associated front channel section 20 of the second component 14. In this way, according to the arrow representation, the flow is deflected at a right angle by the closure plate 52 and flows through the individual flow guide channels 24 in a parallel orientation. At the end of the flow guide channels 24, the rear channel sections 20 of the first and second components 12, 14 are then flowed through, with subsequent right-angled deflection of the media flow by the closure plate 52 between the underlying first component 12 and the second component 14. Now in the opposite flow direction, the flow guide channels 24 are again component 12 in the direction of the 3 seen from right to left and at the end, via associated channel sections 20 of the fluid-carrying channel 18 formed in this way, the cooled medium passes through the outlet 44 from the heat exchanger, which in the assembled state is in the 5 While the individual channel sections 20 in the embodiment according to the 1 and 2 are essentially rectangular in shape, these are in the solution according to the 3 to 5 is essentially square in shape. In particular, the box height for the channel sections 20 of the second component 14 is such that they are flush with the zigzag-shaped configuration of the guide plate 38.

As can be seen in particular from the 4 The frame 22 for the first component 12 is again constructed from individual segments, with two opposing longitudinal bars or strips 36, to which the frame-shaped channel sections 20 are connected at the ends, once on the right side to form a continuous fluid-carrying channel 18; once on the left side closed by the end plate 52. However, it is also possible to construct the frame-shaped enclosure for the channel sections 20 and the two longitudinal bars or strips 36 according to the illustration according to the 4 by a single frame 22 in a die-casting or injection-molding process in one piece (not shown). In all representations of the stacked assembly 10, for the sake of simplicity, the third components 16 are not explicitly shown due to the thin-walled plate design; nevertheless, they always run between the first and second components 12, 14 as well as between the second and the subsequent first component 14, 12 in order to create a secure soldered connection between the individual plates of the heat exchanger. With the heat exchanger solution according to the invention, a wide variety of heat exchanger designs can be achieved in the sense of the modular system, as can be seen, for example, in DE 10 2014 001 703 A1 The cross-flow heat exchanger as a whole can preferably be manufactured in a brazing process, whereby a fluid-tight connection is created between individual strips 36 and the frames 22 by the same brazing process as in the manufacture of the heat exchanger.

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 20 208 748 U1 [0003]
• DE 10 2010 046 913 A1 [0004]
• DE 102 30 042 A1 [0005]
• DE 10 2014 001 703 A1 [0028]

Claims (12)

A cross-flow heat exchanger in plate and strip construction, consisting of a plurality of individual components (12, 14, 16) that form a stack (10) with one another, with at least - a first component (12) that allows fluid passage of a medium in one direction, - a second component (14) that allows fluid passage of this or another medium in a further direction, - a third component (16) that is arranged between the first (12) and the second (14) components and creates a fixed connection between them, and - fluid-carrying channels (18) that extend at least partially through the stack (10) at its ends, and of which at least one channel section (20) serves to supply the medium for the first component (12) and another channel section (20) serves to remove it. Cross-flow heat exchanger according to Claim 1 , characterized in that the first component (12) is enclosed on the outer circumference by a frame (22), the overall height of which corresponds to the overall height of at least one flow guide channel (24) which extends in a fluid-conducting manner between two channel sections (20) adjacent to said channel sections, which are at least partially enclosed by said frame (22). Cross-flow heat exchanger according to Claim 1 or 2 , characterized in that the frame (22) is formed in one piece throughout, or is composed of individual strip-shaped frame parts (28) which, when adjacent to one another, leave a corner region (30) free. Cross-flow heat exchanger according to one of the preceding claims, characterized in that the components (14, 16) adjacent to the frame parts (28) in the stack assembly (10) have a contour recess (32) following the respective corner region (30). Cross-flow heat exchanger according to one of the preceding claims, characterized in that the corner regions (30) and contour recesses (32) arranged one above the other in the stacking sequence form an engagement possibility for a rod-like assembly aid and/or serve to introduce a weld seam (34). Cross-flow heat exchanger according to one of the preceding claims, characterized in that the third component (16) is formed from a flat plate which has recesses in the size of the adjacent channel sections (20) and which is coated with solderable materials. Cross-flow heat exchanger according to one of the preceding claims, characterized in that the fourth component (40) arranged at the top and bottom in the stacking sequence is each formed from a flat end plate, at least one of which has the inlet (42) and/or outlet (44) for the one medium, which is formed from a separate connecting piece (46) which is placed on one side of the end plate and is firmly connected to it. Cross-flow heat exchanger according to one of the preceding claims, characterized in that the free cross sections for the individual channel sections (20) are rectangular, preferably square. Cross-flow heat exchanger according to one of the preceding claims, characterized in that when using a plurality of flow guide channels (24) for the one medium, these are each formed from a longitudinal channel which extends from a channel section (20) at one end to the opposite channel section (20) at the other end. Cross-flow heat exchanger according to one of the preceding claims, characterized in that the second component (14) has at least one guide plate (38) which opens into the open at the free end faces of the heat exchanger and which runs transversely to the flow guide channels (24) of the respective first component (12). Cross-flow heat exchanger according to one of the preceding claims, characterized in that it can be manufactured in one brazing process step. Cross-flow heat exchanger according to one of the preceding claims, characterized in that a fluid-tight connection is created between individual strips (36) and the frames (22) by the same soldering process as in the manufacture of the heat exchanger.

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