Patent Application
20190063844
The invention relates to a plate-type heat exchanger, and to a method for producing such a plate-type heat exchanger.
In the production of plate-type heat exchangers, in particular brazed plate-type heat exchangers composed of aluminum, the modular form of construction is often selected in order thus to obtain larger units with tubing and to save effort and costs for the tubing. For this purpose, two or more heat exchanger blocks (modules) are connected for example with the aid of a connecting layer to form a larger unit, the plate-type heat exchanger to be produced. By inserting a sheet strip at the edge between two blocks and welding the sheet strip to the blocks, the blocks are connected to one another. The weld seams then run along the outer edge of the blocks. Consequently, the blocks or modules are in fact also connected to one another only at the outer edge. In this case, the connection may be formed peripherally at the edge, but may also have interruptions in the connection along the edge.
From a mechanical standpoint, the modular connection constitutes a geometric discontinuity because it exists only at the outer edge and often also has interruptions. In the past, damage has been observed in some individual cases, which forms precisely at said positions because the modular connection constitutes a stress concentration. Thermal deformations are imparted as a result of the temperature response of the plate-type heat exchanger. The modular connection constitutes an obstruction to deformation and a thermal barrier between adjacent modules or blocks. This gives rise to mechanical constraint stresses, which are intensified even further by the discontinuity at the modular connection.
Taking this as a starting point, the present invention is based on the object of specifying a plate-type heat exchanger and a method for the production thereof, which heat exchanger and method alleviate the aforementioned problems.
This object is achieved by a plate-type heat exchanger having the features of claim 1 and by a method having the features of claim 7. Advantageous configurations of the invention are specified in the corresponding dependent claims and are described below.
As per claim 1, a plate-type heat exchanger with at least one first and one second heat exchanger block is disclosed, wherein each heat exchanger block has multiple separating plates which are arranged parallel to one another and form a multiplicity of heat exchange passages for fluids involved in the heat exchange, wherein the heat exchanger blocks are outwardly delimited by cover plates, wherein a first cover plate of the first heat exchanger block is fixed to an opposite second cover plate of the second heat exchanger block, wherein according to the invention, at least one elongate first profile is fixed to the first cover plate, and wherein at least one elongate second profile, which runs parallel to the at least one first profile, is fixed to the second cover plate such that the two profiles are opposite one another in a direction which runs parallel to the two cover plates, and wherein, between the two profiles, one intermediate space is present, in which space an elongate element is arranged in a frictionally engaging manner such that the two cover plates and thus the two heat exchanger blocks are fixed to one another, wherein in particular the elongate element is formed as a hollow profile.
According to a preferred embodiment of the plate-type heat exchanger according to the invention, it is provided that the elongate element engages both into a recess of the first profile and into a recess of the second profile, wherein the two recesses each form a region of the intermediate space and are opposite one another in said direction and face one another.
Recesses of said type, however, are not absolutely necessary for producing said frictional engagement. Thus, the two profiles may also have planar sides which face one another and consequently form no recess at all, wherein here, the elongate element is arranged in a frictionally engaging manner with the sides, facing one another, of the profiles in the intermediate space delimited by the two sides.
According to a further preferred embodiment of the plate-type heat exchanger according to the invention, it is provided that the elongate element is arranged in a frictionally engaging and form-fitting manner in the two recesses or in the intermediate space.
The invention thus advantageously allows a full-area connection between the two cover plates or heat exchanger blocks, said connection ensuring a particularly good thermally heat-conducting contact between the blocks, with the result that temperature differences between the blocks can easily be reduced. Furthermore, a mechanical connection between the modules is achieved, and a stress concentration is mitigated or reduced.
The at least one first profile and the at least one second profile and also the elongate element may each extend along an entire side length of the two cover plates, with the result that the entire surface of the cover plates can be used for the mechanical connection of the two blocks. In this case, the profiles and the elongate element may extend for example along the vertical or along the horizontal.
According to one embodiment of the invention, it is provided with particular preference that, for the purpose of producing the frictional engagement or the frictional engagement and form fit, the cross section of the elongate element arranged in the intermediate space is widened by deformation of the elongate element. This is preferably performed hydraulically in that a probe, for example, is introduced into an inner space of the elongate element (for example hollow profile), and the cross section or outer diameter of the respective elongate element is increased by being acted on by a fluid (for example water or oil), which is supplied via the probe, such that the elongate element is situated in the recesses and/or in the intermediate space in each case in a frictionally engaging manner or frictionally engaging and form-fitting manner.
The advantage of the (in particular hydraulic) widening is in this case that production inaccuracies (for example warpage of the modules or blocks in the course of the brazing process) can be compensated. In this way, a frictional engagement or frictional engagement and form fit is/are achieved, which can transmit forces between the blocks. Furthermore, a heat-conducting contact between the modules is established. This results in the achievement of a uniform and in particular planar joint, which is also able to transmit mechanical and thermal loads. Thus, temperature differences between modules or blocks are compensated or reduced, and mechanical discontinuities are mitigated by reduction of the notch effect. This allows larger units to be produced without the risk of local mechanical overloading. The stress concentrations at the beginning/end of the modular connection, which arise with the existing embodiment of the modular connection and which are also often the cause of damage, are eliminated by the invention because the joint of the modules thereby becomes planar and the local stress concentration is removed. The operational reliability and failure safety or the lifetime of the heat exchanger is thus increased.
In principle, the connection is even releasable again by pulling the elongate element (for example hollow profile) out of the intermediate space.
It is provided with particular preference that the elongate element has at least one portion which is formed in a manner complementary to the recesses of the recesses adjoining on both sides or complementary to the intermediate space into which the elongate element is to be introduced. Here, the elongate element is preferably introducible with play into the intermediate space along its longitudinal axis such that said portion is positionable in the recesses. Thereafter, the frictional engagement or frictional engagement and form fit can be established in that the elongate element is correspondingly deformed (see also below).
According to one embodiment of the invention, it is provided that the intermediate spaces are of circular or at least approximately circular form in cross section. The intermediate space may also be of different form in cross section, however.
In this case (as below), the corresponding cross-sectional plane of the aforementioned cross sections extends perpendicularly with respect to the longitudinal axis or the direction of longitudinal extent of the parallel profiles and of the elongate element.
Furthermore, according to one embodiment of the invention, the elongate element is preferably formed as a hollow profile which may have for example a circular cross section.
Furthermore, according to one embodiment of the invention, it is provided that the two outer sides, averted from one another, of the respective first or second profile are of concave form in cross section. The two outer sides of a profile thus preferably define in each case a recess, or depression, which is concave, preferably semicircular, in cross section.
However, the recesses may also be of triangular form in cross section.
In the case of an intermediate space which is circular or approximately circular in cross section, the elongate element is preferably a hollow profile which is correspondingly circular in cross section. The hollow profile can then advantageously be introduced with a small amount of play into the intermediate space or the recesses formed as concave depressions. Wherein, owing to the formation of the elongate element in a manner complementary to the intermediate space or the recesses, only a relatively small deformation of the tube is necessary to produce said frictional engagement or frictional engagement and form fit.
In the case of recesses which are triangular in cross section, the elongate element may, for the aforementioned reasons, be for example a quadrangular hollow profile which is correspondingly formed in cross section.
Other complementary pairings of elongate elements and corresponding intermediate spaces or recesses are likewise conceivable.
Preferably, the recesses or depressions in each case extend over the entire respective profile in the direction of longitudinal extent or in the direction of the longitudinal axis of the respective profile.
Furthermore, according to one embodiment of the invention, it is provided that the first profile is brazed fixedly or welded fixedly to the first cover plate, and/or that the second profile is brazed fixedly or welded fixedly to the second cover plate.
According to one embodiment of the invention, it is furthermore provided that a plurality of elongate first profiles, which run parallel to one another, is fixed to the first cover plate, and that a plurality of elongate second profiles, which run parallel to one another, is fixed to the second cover plate, such that a second profile is arranged between in each case two adjacent first profiles in said direction, wherein, between every second profile and the first profiles adjacent on both sides, in each case one intermediate space is present, in which space in each case one elongate element is arranged in a frictionally engaging manner with the adjacent first profile and the adjacent second profile such that the two cover plates and thus the two heat exchanger blocks are fixed to one another.
According to one embodiment, it is preferably provided that the respective elongate element engages both into a recess of the adjoining first profile and into a recess of the adjoining second profile, wherein the two recesses each form a region of the respective intermediate space and are opposite one another in said direction and face one another.
Furthermore, according to one embodiment of the invention, it is provided that the respective elongate element is arranged in a frictionally engaging and form-fitting manner in the two associated recesses or in the intermediate space.
The respective elongate element and the associated recesses or the associated intermediate space may in turn be formed according to one of the above-described embodiments.
According to a further aspect of the invention, a method for producing a plate-type heat exchanger or for connecting at least two heat exchanger blocks to form such a plate-type heat exchanger is proposed.
The method according to the invention provides that each heat exchanger block has multiple separating plates which are arranged parallel to one another and form a multiplicity of heat exchange passages for fluids involved in the heat exchange, and that the heat exchanger blocks are outwardly delimited by cover plates, wherein at least one elongate first profile is fixed to a first cover plate of the first heat exchanger block, and wherein at least one elongate second profile is fixed to a second cover plate of the second heat exchanger block, wherein the two cover plates are arranged opposite one another in such a way that the two profiles are opposite one another in a direction which runs parallel to the two cover plates, wherein, between the two profiles, an intermediate space is present, in which space an elongate element is arranged in a frictionally engaging manner with the two profiles such that the two cover plates and thus the two heat exchanger blocks are fixed to one another, wherein in particular, the elongate element is formed as a hollow profile.
According to one preferred embodiment of the method according to the invention, it is provided that the elongate element is arranged in the associated intermediate space such that it engages into a recess of the adjoining first profile and into a recess of the adjoining second profile.
Preferably, the elongate element is arranged in a frictionally engaging and form-fitting manner in the two associated recesses.
According to one embodiment of the method according to the invention, it is provided that the intermediate spaces are of circular or substantially circular form in cross section. According to one embodiment of the method according to the invention, the elongate elements are correspondingly formed as hollow profiles, or tubes, which are circular in cross section (see also above). Other cross-sectional shapes of the intermediate spaces or recesses, and of the tubes, are likewise conceivable.
Furthermore, according to a preferred embodiment of the method according to the invention, said outer sides of the profiles (see above) or the recesses defined by the outer sides are of concave form in cross section, specifically preferably formed as depressions which are semicircular or substantially semicircular in cross section. The recesses may also be formed as depressions which are triangular in cross section. Further cross-sectional shapes of the recesses are likewise conceivable (see also above).
According to a particularly preferred embodiment of the invention, it is provided that the elongate element is arranged for example with play in the associated intermediate space and subsequently widened in cross section by deformation such that the elongate element is arranged in a frictionally engaging or frictionally engaging and form-fitting manner in the associated recesses of in the associated intermediate space.
Particularly preferably, the elongate element is widened in cross section as soon as it has been arranged in the associated intermediate space. In this way, an inner form fit with the two adjoining (first and second) profiles is preferably produced. Preferably, the elongate element or hollow profile is widened hydraulically, for example in that a probe is introduced into the inner space of the hollow profile, wherein the inner space is acted on by a fluid (for example water or oil) via the probe such that said widening or enlargement of the outer diameter of the hollow profile is effected. The action by the fluid is in particular performed such that the hollow profile flows plastically in order to achieve the best possible form fit with the surrounding profiles.
Furthermore, according to one embodiment of the method according to the invention, it is provided that the at least one first profile is brazed fixedly or welded fixedly to the first cover plate, and/or that the at least one second profile is brazed fixedly or welded fixedly to the second cover plate.
Furthermore, according to one embodiment of the method according to invention, it is provided that a plurality of elongate first profiles, which run parallel to one another, is fixed to the first cover plate, and that a plurality of elongate second profiles, which run parallel to one another, is fixed to the second cover plate, wherein the two cover plates are arranged opposite one another such that a second profile is arranged between in each case two adjacent first profiles in said direction, wherein, between every second profile and the first profiles adjacent on both sides, in each case one intermediate space is present, in which space in each case one elongate element is arranged in a frictionally engaging manner with the adjacent first profile and the adjacent second profile such that the two cover plates and thus the two heat exchanger blocks are fixed to one another.
According to one embodiment of the method according to the invention, it is preferably furthermore provided that the respective elongate element engages both into a recess of the adjoining first profile and into a recess of the adjoining second profile, wherein the two recesses each form a region of the respective intermediate space and are opposite one another in said direction and face one another.
Furthermore, according to one embodiment of the method according to the invention, it is provided that the respective elongate element is arranged in a frictionally engaging and form-fitting manner in the two in each case associated recesses or in the in each case associated intermediate space.
The respective elongate element and the associated recesses or the associated intermediate space may in turn be formed according to one of the above-described embodiments.
Further features and advantages of the invention will be discussed in more detail below on the basis of the figure description of exemplary embodiments in which:
The two heat exchanger blocks 10a, 10b are preferably plate-type heat exchangers, preferably brazed plate-type heat exchangers composed of aluminum. Such heat exchangers are used in numerous installations under a wide variety of pressures and temperatures. For example, they are used for the separation of air, the liquefaction of natural gas or in installations for producing ethylene. Such plate-type heat exchangers are shown and described for example on page 5 in “The standards of the brazed aluminium plate-fin heat exchanger manufacturers' association” ALPEMA, third edition, 2010.
The two heat exchanger blocks 10a, 10b each have multiple separating plates 4 (for example in the form of separating sheets), which are arranged parallel to one another and form a multiplicity of heat exchange passages 1 for the media to be brought into heat exchange with one another. The heat exchange passages 1 are closed off outwardly by edge bars 8 (for example sheet strips), hereinafter also referred to as side bars 8, fitted flush on the edge of the separating plates 4. Arranged within the heat exchange passages 1 are for example corrugated heat-conducting structures 3 (for example in the form of sheets), which are also referred to as fins 3. The separating plates 4, fins 3 and side bars 8 are connected fixedly to one another and thus form a compact heat exchanger block 10a or 10b. Outwardly, the two heat exchanger blocks 10a, 10b are each outwardly delimited by cover plates 5a or 5b (for example in the form of cover sheets).
For supplying and discharging the heat-exchanging media, semi-cylindrical collectors 7 with connecting pieces 6 which serve for the connection of supplying and discharging pipelines are fitted via inlet and outlet openings 9 of the heat exchange passages 1. The collectors 7 are also referred to hereinafter as headers 7. The inlet and outlet openings 9 of the heat exchange passages 1 are formed by so-called distributor lamellae or distributor fins 2, which provide a uniform distribution of the media within the individual heat exchange passages 1. The media flow through the heat exchange passages 1 in the channels formed by the fins 3 and the separating plates 4. It is possible already to fit the collectors 7 and connecting pieces 6 to the individual block 10a or 10b. According to one embodiment, it is alternatively also possible for all or individual collectors 7 to be fixed to the two blocks 10a, 10b only after the latter have been fixed to one another according to invention. Here, it is possible for example for a header 7 to extend over both blocks 10a, 10b, or to be fixed to both blocks 10a, 10b, in order to charge said blocks with a medium or to draw off a medium from both blocks 10a, 10b (this being indicated by dashed lines in
The fins 3 are, at their points of contact, brazed to the separating sheets 4, as a result of which an intensive heat-conductive contact between the fins 3 and the separating sheets 4 is established. This improves the heat exchange between the different media, which flow alternately in adjacent heat exchange passages 1.
The blocks 10a, 10b are preferably formed from aluminum, wherein the components are connected to one another by way of brazing. As material, however, high-grade steel may also be used. The fins, separating sheets, distributor fins, cover plates and side bars, provided with brazing material, are stacked one on top of the other and subsequently brazed in a furnace to form a heat exchanger block 10a or 10b. The headers 7 with connecting pieces 6 are then welded onto the heat exchanger blocks 10a, 10b.
As can be seen from
For the connection of the two heat exchanger blocks 10a, 10b, these are arranged such that the first and the second cover plates 5a, 5b face one another and run parallel to one another in such a way that the at least one first profile and the at least one second profile are opposite one another in a direction R, which runs parallel to the two cover plates (and, here, perpendicular to the vertical), such that at least one intermediate space 15 in which an elongate element 13 is arranged in a frictionally engaging manner and preferably also form-fitting manner with the adjoining profiles 11, 12 is created.
Preferably, as shown in
As per
If the two cover plates 5a, 5b as per
Finally,
A hydraulic fluid F, for example water or oil, is then introduced via a supply line 24 into a channel 21 formed by the probe, which channel opens into lateral openings 22 of the portion 20b of the probe 20 such that the fluid F is able to act on the inner wall of the respective hollow profile 13. This causes the respective hollow profile 13 to widen to a larger outer diameter D′, which anchors the respective hollow profile 13 in the associated intermediate space 15 or in the recesses 110 and 120 in a form-fitting manner. The action by the fluid F is preferably performed such that the respective hollow profile 13 flows plastically in order to achieve the best possible form fit with the surrounding profiles 11, 12.
D, D′
| Number | Date | Country | Kind |
|---|---|---|---|
| 16000630.0 | Mar 2016 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/025042 | 3/8/2017 | WO | 00 |
