EP0524926B1 - Heat exchanger using sintered metal - Google Patents

Abstract

Described is a modular-design heat exchanger with at least one heat-exchange plane, each plane having a module-holder (10, 20, 30, 40, 60) which holds a multiplicity of removeable heat-exchange modules (1, 50). Each individual heat-exchange module (1, 50) has a boundary wall (2, 52) through which the heat passes from the heat-input side of the heat exchanger to the heat-output side. Located on at least one side of the boundary wall (2, 52) is porous, permeable sintered-metal material (4, 6, 54, 56). The module holder (10, 20, 30, 40, 60), together with most of the modules (1, 50), form a heat-flow channel for the heat-input and/or the heat-output side of the heat exchanger.

Description

The invention relates to a heat exchanger in modular design according to the features specified in the preamble of claim 1.

A heat exchanger of this type has become known from US-A-34 93 042. It has at least one heat exchanger level, each of which has a module receiving part with a plurality of heat exchanger basic modules installed therein, the individual heat exchanger basic modules each having a boundary wall through which the heat transfer takes place from the heat-emitting side of the heat exchanger to the heat-absorbing side of the heat exchanger, at least one side of the boundary wall is provided with a packing made of porous, flowable sintered metal and the module receiving part, together with the basic modules, defines a second flow channel for the heat-emitting and / or heat-absorbing side of the heat exchanger. Despite the modular construction thus implemented, it is nevertheless not possible in the known heat exchanger to vary and change it after its assembly in accordance with a modular principle, for example in order to meet changing demands or performance requirements. Because that required the destruction of the heat exchanger housing that accommodates the basic modules in the known heat exchanger.

In other powder-metallurgy heat exchangers, ie heat exchangers with sintered metal, it is known to improve the heat conduction or the heat transfer performance between a heat-absorbing side and a heat-emitting side in that porous packings which can be flowed through by sintering or sinter-like processes increase the active heat exchange surfaces. For example, from DE-GM 72 27 102 a heat exchanger is known in which a tubular Flow channel filled with sintered metal and the tubular flow channel is surrounded by a tubular jacket made of sintered metal, which in turn is enclosed by a housing. Similar constructions are known from DE 14 42 601 A1, DE-GM 80 01 502 and DE 34 35 319 A1. In the construction according to DE 34 35 319 A1, the sintered metal is additionally coated on one side of the heat exchanger with a catalyst substance, so that catalytic reactors are present.

Because of the large inner surface of the sintered metal that is active for heat exchange, these heat exchangers had very high α values in relation to the area of the tube wall separating the two sides of the heat exchanger. A disadvantage of such heat exchangers, however, is the comparatively high pressure loss in the porous sintered metal in relation to the section through which the flow passes.

In order to avoid excessive pressure losses, it is known from DE 19 02 229 A1 to use coarser structures with substantially larger pore diameters, in particular spherical matrix arrangements, instead of the fine-pored sintered metal. In this known heat exchanger, the pressure loss is lower than in the case of the ones described above, but the α value deteriorates as a result.

Another disadvantage of all the structures described above is that each of the known heat exchangers must be designed for a specific heat exchanger output. In addition, the known components have to be specific to a specific function, e.g. Recuperator, evaporator, etc., be designed. The manufacturing costs of the known structures are comparatively high because of high reject rates, since changes in shape occurring during sintering can render the entire component unusable.

The invention has for its object to provide a heat exchanger with sintered metal for different Applications and functions is inexpensive to manufacture.

This object is achieved with the features contained in the characterizing part of claim 1. Above all, because the receiving part connected to the flow channels of the basic heat exchanger module via inflow and outflow areas is formed in two parts, with half-shell-like housing parts sealed against one another, which can be detached at any time, there is a simple possibility of removing the modules from the receiving points to be removed without this destroying the modules and / or the module receiving part or the heat exchanger housing. Since several basic heat exchanger modules with sintered metal can be detachably inserted in a module receiving part, heat exchangers with different performance levels can be easily realized. A plurality of basic heat exchanger modules can be detachably inserted into one and the same module receiving part, ie the basic heat exchanger modules can also be subsequently removed from the module receiving part (s) without damaging the modules. The detachability of the basic heat exchanger modules in the module receiving parts ensures that a heat exchanger according to the invention in modular design can subsequently perform different functions and / or services can be adjusted. By inserting a different number of basic heat exchanger modules in a module receiving part, heat exchanger levels with different heat outputs can be realized. The performance range can be increased as desired by combining several heat exchanger levels with one and the same heat exchanger basic module. The heat exchanger levels combined with each other to form a heat exchanger can differ from one another in terms of performance, function and size.

A particular advantage is that the manufacturing costs of the heat exchanger according to the invention are significantly lower than the manufacturing costs of comparable conventional heat exchangers. This is due to the use of standardized components - the heat exchanger basic module and module receiving part. In addition, deformations occurring during sintering do not mean that the entire heat exchanger is rejected, but only the respective basic module. The heat exchanger base modules, which are comparatively small in terms of their size, are easier to control in terms of production technology than large-volume parts, i. H. the reject rate is lower.

On the basis of comparable heat exchanger performances, the heat exchanger according to the invention succeeds in reducing the production costs by at least 30%. In particular with heat exchangers under pressure with higher outputs, even greater savings potential can be realized, since the compact design has a cost-effective effect on the size of the pressure-stressed jacket pipes and pressure covers.

By splitting the mass flow into many parts and treating them in the "short" heat exchanger basic modules, the excellent thermal properties of a sintered pipe can be used, without having to put up with comparatively high pressure losses. By constructing a specific heat exchanger from a plurality of basic heat exchanger modules, it is possible to minimize the high pressure losses which occur in heat exchangers with sintered metal, since very short flow paths can be achieved in the basic heat exchanger modules. By parallel flow to the plurality of basic heat exchanger modules, pressure losses can be achieved, as are customary in conventional conventional heat exchangers, such as, for example, tube bundle or plate heat exchangers.

According to the particularly preferred embodiment according to claim 2, the basic heat exchanger module consists of a short piece of pipe which forms the boundary wall between the heat-absorbing and the heat-emitting side of a heat exchanger. On the one hand, this leads to a very compact design and, on the other hand, it is easy to handle in terms of production technology or sintering technology.

According to the preferred embodiment according to claim 3, the tube interior and / or the outside of the tube piece is provided with a packing made of porous, flowable sintered metal. These basic heat exchanger modules in the form of short pipe sections with sintered metal filling and / or sintered metal jacket are comparatively simple and inexpensive to manufacture.

By coating a sintered packing with a catalyst substance, catalytic reactors can be realized for different purposes and with different performance characteristics.

The further subclaims relate to advantageous refinements of the invention.

Details and advantages of the present invention will become apparent from the following description with reference to the drawing.

Fig. 1A

einen Schnitt durch eine erste Ausführungsform eines Wärmetauscher-Grundmoduls,

Fig. 1B

eine perspektivische Darstellung des Wärmetauscher-Grundmoduls von Fig. 1A,

Fig. 2A

eine Ansicht der Innenseite eines Teiles eines zweiteiligen Modul-Aufnahmeteils,

Fig. 2B

einen Schnitt durch das in Fig. 2A dargestellte Teil entlang der Linie A-A,

Fig. 3A

eine analoge Ansicht zu Fig. 2A einer zweiten Ausführungsform der vorliegenden Erfindung,

Fig. 3B

eine perspektivische Darstellung einer Ausführungsform einer Wärmetauscherebene,

Fig. 4

in analoger Darstellung zu Fig. 2A eine dritte Ausführungsform,

Fig. 5

in analoger Darstellung zu Fig. 2A eine vierte Ausführungsform,

Fig. 6

eine zweite Ausführungsform eines Wärmetauscher-Grundmoduls,

Fig. 7

eine Schnittdarstellung einer weiteren Ausführungsform eines Modulaufnahmeteils, und

Fig. 8

in analoger Darstellung zu Fig. 2A eine weitere Ausführungsform einer Hälfte eines Modulaufnahmeteils.

It shows:

Fig. 1A

2 shows a section through a first embodiment of a basic heat exchanger module,

Figure 1B

1 shows a perspective illustration of the heat exchanger basic module from FIG. 1A,

Figure 2A

a view of the inside of a part of a two-part module receiving part,

Figure 2B

3 shows a section through the part shown in FIG. 2A along the line AA,

Figure 3A

2 shows a view analogous to FIG. 2A of a second embodiment of the present invention,

Figure 3B

2 shows a perspective illustration of an embodiment of a heat exchanger level,

Fig. 4

in a representation analogous to FIG. 2A, a third embodiment,

Fig. 5

in a representation analogous to FIG. 2A, a fourth embodiment,

Fig. 6

a second embodiment of a heat exchanger basic module,

Fig. 7

a sectional view of another embodiment of a module receiving part, and

Fig. 8

in a representation analogous to FIG. 2A, a further embodiment of one half of a module receiving part.

Figs. 1A and 1B show a preferred embodiment of a heat exchanger basic module 1 which is part of the heat exchanger according to the invention described below. The basic heat exchanger module 1 has a tubular boundary wall 2 with a circular cross section. The tubular boundary wall 2 or the pipe section 2 is surrounded by a tubular outer packing 4 made of porous, flowable sintered metal, which also has a circular cross section. The pack 4 does not enclose the entire length of the tubular boundary wall 2. The interior of the pipe section 2 is filled with an inner pack 6 made of porous, flowable sintered metal. Again, not the entire length of the pipe section 2 but only part of it is filled with sintered metal. In the embodiment shown in FIG. 1, the length of the filling or the covering of the pipe section 2 by the outer or inner packing made of sintered metal is the same. The parts of the pipe section 2 that are not enveloped or filled by the packs 4 and 6 form connecting pieces 5 and 7. the boundary wall is sintered. The sintering of the packs 4 and 6 with the boundary wall or the pipe section 2 ensures an optimal heat transfer. The inside of the pipe section 2 forms an inner flow channel 8 for the heat-emitting or heat-absorbing side. The position of the outer packing 4 defines an outer flow channel 9.

2A and 2B show a first embodiment of a module receiving part of a heat exchanger according to the invention in a modular design. 2A shows one half of a module receiving part 10 from the inside and FIG. 2B shows the entire module receiving part 10 consisting of two parts according to FIG. 2A in a section along the line AA from FIG. 2A. The module receiving part 10 has a module holder 12, into which, for example, two heat exchanger basic modules 1 are releasably inserted, which are placed one behind the other with adjoining connecting pieces 5 and 7 in the module receiving part. The two basic modules are sealed or welded to one another in such a way that the interior of the tube pieces 2 together form a continuous flow channel. The various flow channels for the heat-absorbing or heat-absorbing medium can be seen from FIG. 2A. The connecting pieces 5 and 7 of the heat exchanger basic module 1 open into areas 14 and 15, into which the medium guided in the inner flow channel 8 is supplied or from which this medium is removed. The medium flowing through the outer packing 4 of sintered metal is supplied or discharged in annular regions 16 and 17. The two basic modules 1 are inserted into one half of the module receiving part 10 and the two parts or halves of the module receiving part 10 are assembled as shown in FIG. 2B and screwed together by means of screws 18. The two parts of the module receiving part 10 or the flow channels for the heat-absorbing or heat-dissipating medium are sealed by seals 19. Alternatively, the two parts can also be welded if there are special tightness requirements.

3A and 3B show a second and a third embodiment of a heat exchanger level according to the present invention. FIG. 3A shows, in an analogous representation to FIG. 2A, a half 20a of a module receiving part 20 for nine basic heat exchanger modules 1 arranged in the form of a spoke, only one basic heat exchanger module 1 being shown. 3B shows a perspective illustration of a disassembled heat exchanger plane with the two halves 20a and 20b of a module receiving part 20 in which eight heat exchanger basic modules 1 can be inserted into module holders 22 in the manner of the spokes of a wheel. In the assembled state, the module receiving part 20 has an annular cylindrical shape with an inner cylinder wall 24 and an outer cylinder wall 25. The connectors 5 and 7 of the heat exchanger basic modules 1 pass through the inner cylinder wall 24 and the outer cylinder wall 25. The heat transport medium flowing in the inner flow channels 8 is supplied in the region of the inner cylinder wall 24 and flows via the connectors 5 into the inner flow channels 8 The heat transfer medium flows out of the heat exchanger level again via the connection pieces 7. The heat transport medium flowing through the outer packing 4 of sintered metal is supplied or discharged in regions 26 and 27. 3A or 3B can be used particularly advantageously if a particularly good pressure balance between the individual modules is desired, since the flow paths of the individual basic heat exchanger modules are completely identical. As indicated in FIG. 3A, the heat exchanger level can be inserted into a tubular or cylindrical pressure jacket 28.

Fig. 4 shows a fourth embodiment of a heat exchanger level with a module receiving part 30 consisting of two halves 30a and 30b. At this heat exchanger level, four basic heat exchanger modules 1 are inserted into module holders 32 in the module receiving part 30. The axes of the inner flow channels 8 of the individual heat exchanger basic modules 1 lie in the module receiving part 30 with a circular cross section parallel to the sides of an inscribed square. The connecting pieces 5 of the heat exchanger basic modules 1 open into a region 33a of a first inlet duct and into a region 35a of a second inlet duct for the heat transport medium flowing in the inner flow duct 8. The connectors 7 of the heat exchanger basic modules 1 open out in a region 33b of a first outlet duct and in a region 35b of a second outlet duct. The heat transport medium flowing in the outer flow channel 9 is supplied in a region 36 or 37 and withdrawn from the collecting region 38 again from the heat exchanger or the heat exchanger level. The heat transfer medium is guided in counter-current in the heat exchanger basic modules 1.

FIG. 5 shows a further embodiment of a half 40a of a module receiving part 40 of a heat exchanger level, which, like the heat exchanger level of FIG. 3B, offers space for eight basic heat exchanger modules 1. However, the outside diameter of the module receiving part 20 is smaller than the outside diameter of the module receiving part 20. The connecting pieces 5 of the heat exchanger basic modules 1 open into a region 42, via which the heat transport medium flowing in the inner flow channel 8 is supplied. The connecting pieces 7 of the heat exchanger basic modules 1 open into an area 44 or 45 from which the heat transport medium flowing in the inner flow channel 8 is withdrawn. The heat transport medium flowing in the outer flow channel 9 is supplied in a region 46 and withdrawn from regions 48 and 49, respectively.

6 shows a section through a heat exchanger basic module 50 according to a second embodiment. The basic heat exchanger module 50 has a tubular boundary wall 52. The tubular boundary wall 52 or the tube piece 52 is surrounded by a tubular outer packing 54 made of porous, flowable sintered metal, which is slightly conical in shape. The packing 54 does not enclose the entire length of the tubular boundary wall 52. The interior of the pipe section 52 is filled with an inner packing 56 made of porous, flowable sintered metal. The packs 54 and 56 are sintered with the boundary wall or the pipe section 52 in order to achieve an optimal heat transfer between the two packs 54 and To enable 56 of sintered metal over the boundary wall 52. The parts of the pipe section 52 which are not enveloped or filled by the packs 54 and 56 form connecting pieces 55 and 57. The interior of the pipe section 52 forms an inner flow channel 58 for the heat-emitting or heat-absorbing side. The position of the outer packing 54 defines an outer flow channel 59. Apart from the conically shaped outer sinter packing 54, the basic heat exchanger module 50 corresponds to the basic module 1.

FIG. 7 shows a section through a further embodiment of a heat exchanger level consisting of a one-piece module receiving part 60 into which a conically shaped basic heat exchanger module 50 can be inserted. The heat transport media are conducted in countercurrent or cocurrent through the flow channels 58 and 59, respectively.

If several different heat exchanger levels with different functions are connected to each other, it may be necessary to blind one or more levels. Flow channels 62 are provided for this purpose.

8 schematically shows a further embodiment of a heat exchanger level with a module receiving part 70 consisting of two halves 70a and 70b, in which seven basic heat exchanger modules 50 are arranged vertically in module holders 72. That is, the axes of the inner flow channels are arranged perpendicular to the plane in which the two halves 70a and 70b of the module receptacle 70 are folded together. The heat transport medium flows through the outer flow channel of the heat exchanger basic modules 50 and is collected in the area 52 and can be fed to a separation mechanism, not shown. The heat transport medium flowing in the inner flow channel can also be passed through channels 74 and 75. In the edge area of the module receiving part 70 circumferential flow channels are provided which correspond to the channels 62 in their function. A vertical section through the module holders 72 corresponds to the sectional illustration according to FIG. 7.

The embodiment according to FIG. 8 is particularly suitable for cold evaporators. It could be empirically determined that an otherwise unchanged basic heat exchanger module 50 for cold evaporation of R12 for the cooling of compressed air yielded approximately 20% higher K values if, according to the embodiment of FIGS. 7A, 7B and 8 was arranged vertically with a steam guide from bottom to top and not horizontally. At the same time, the steam could be overheated up to 5 ° C without resulting in a measurable deterioration in the air outlet temperature.

With the heat exchangers described above, it was possible, for example, to design modules for drying compressed air which, in the recuperation section with a flow length of 65 mm, manage a temperature drop of 18.5 ° C at an inlet temperature of 35 ° C and an evaporation temperature of 0 ° C in the cold evaporator showed a flow path of only 45 mm. With the same boundary parameters, the developed length of a coaxial heat exchanger (recuperator + cold evaporator) is approx. 6 m. Both heat exchangers meet the criterion of not exceeding a total pressure difference of approx. 160 mbar.

From this example it can be deduced that the flow paths of heat exchangers in modular construction according to the present invention with sintered metal are of the order of magnitude at 2% of conventional systems. The K values can be improved by a factor of 10 regardless of substance and phase, so that about 10% of the pipe wall area of a conventional heat exchanger is required.

Claims (12)

1. Heat exchanger of modular design comprising one or more heat exchanger planes each provided with a module receiving means (10; 20; 30; 40; 60) with heat exchanger base modules (1; 50) mounted therein, said heat exchanger base modules (1; 50) including a partition wall (2; 52) through which the heat transfer from the heat emitting side of the heat exchanger to the heat absorbing side of the heat exchanger takes place, there being provided on at least one side of said partition wall (2; 52) a packing (4,6; 54, 56) made of porous, permeable sintered metal which defines a first flow channel (9), while said module receiving means (10; 20; 30; 40; 60), together with said base modules (1; 50), defines a second flow channel (8) for the heat emitting and/or heat absorbing side of the heat exchanger, characterized in that the module receiving means (10, 20, 30, 40, 60) is in two parts and encloses the heat exchanger base modules in the manner of two half shells which are sealed off against each other and comprise inflow and outflow areas (14,15 and 16,17, respectively) for the fluid carried in said first and second flow channel (8 and 9, respectively), with connecting pieces (5,7) of the heat exchanger base modules (1; 50) terminating in said areas.
2. Heat exchanger of modular design as set forth in claim 1, characterized in that the partition wall (2; 52) of the heat exchanger base module defines a tubular flow channel, and specifically one of circular cross-section, for the heat emitting or heat absorbing side.
3. Heat exchanger of modular design as set forth in claim 2, characterized in that the packing (4, 6; 54, 56) of porous, permeable sintered metal encloses a portion of the longitudinal extension of the tubular flow channel in a tubelike manner and/or completely fills up the interior cross-section of the tubular flow channel over a portion of its longitudinal extension.
4. Heat exchanger of modular design as set forth in any of claims 2 and 3, characterized in that the individual heat exchanger base modules are arranged vertically alongside each other in the module receiving means (10; 20; 30; 40; 60) in the manner of a shell-and-tube heat exchanger.
5. Heat exchanger of modular design as set forth in claim 4, characterized in that the base modules are concave in shape.
6. Heat exchanger of modular design as set forth in any of claims 2 and 3, characterized in that the individual base modules are arranged horizontally in one plane alongside each other in the module receiving means (10; 20; 30; 40; 60).
7. Heat exchanger of modular design as set forth in claim 6, characterized in that the base modules are arranged like the spokes of a wheel in the module receiving means (10; 20; 30; 40; 60).
8. Heat exchanger of modular design as set forth in any of the preceding claims, characterized in that the partition wall (2; 52) is made of aluminium and the sintered metal packing or packings (4, 6; 54, 56) is/are are made of porous sintered aluminium powder or granules.
9. Heat exchanger of modular design as set forth in any of the preceding claims, characterized in that the module receiving means (10; 20; 30; 40; 60) is of circular cross-section.
10. Heat exchanger of modular design as set forth in any of the preceding claims, characterized in that the sintered metal packings are coated with a catalyst material.
11. Heat exchanger of modular design as set forth in any of the preceding claims, characterized in that the individual heat exchanger planes differ in terms of their structure and performance characteristics.
12. Heat exchanger of modular design as set forth in any of the preceding claims, characterized in that the individual heat exchanger planes are arranged inside a common pressurized shell.

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