WO2008119528A1

WO2008119528A1 - Safety heat exchanger

Info

Publication number: WO2008119528A1
Application number: PCT/EP2008/002530
Authority: WO
Inventors: Jürgen Lessing
Original assignee: Lessing Juergen
Priority date: 2007-04-03
Filing date: 2008-03-31
Publication date: 2008-10-09
Also published as: EP2118607A1; DE102007016106A1

Abstract

The invention relates to a safety heat exchanger (24) for exchanging heat between at least two media, wherein a separate conduit system (22,22') is associated with each medium, and wherein the conduit systems are at a spatial distance from each other and are in contact with each other in a heat-conducting manner via heat transfer elements (18,20). The safety heat exchanger has a housing (26) that is closed on all sides and at least partially surrounds the conduit system and the heat transfer elements, in order to thus avoid air exchange between the interior of the housing and the environment to the greatest possible extent, wherein the housing has at least one gas-permeable pressure compensation opening (30) for a continuous pressure compensation between the interior of the housing and the environment.

Description

Jürgen Lessing L 1006 IPWO - Ov / Fa

Safety heat exchanger

The present invention relates to a safety heat exchanger for heat exchange between at least two media, each medium being assigned a separate piping system.

In such safety heat exchangers, undesired mixing of the media between which heat is to be transferred is reliably prevented by spatially separating the individual piping systems, i. spaced from each other, are arranged. Leakage of the piping systems does not necessarily result in mutual contamination of the media. A safety heat exchanger therefore has increased system safety. The separation of the piping systems also simplifies the maintenance of the safety heat exchanger.

Important aspects of such safety heat exchangers are, in addition to the above-mentioned safety aspects, above all their robustness and economic efficiency. It is therefore an object of the invention to provide a safety heat exchanger of the type mentioned, on the one hand inexpensive to manufacture and robust, on the other hand also allows efficient heat exchange between the at least two media of the safety heat exchanger.

This object is achieved by a safety heat exchanger with the features of claim 1. In the safety heat exchanger according to the invention for heat exchange between at least two media each medium is assigned a separate piping system. The piping systems are spaced apart from each other and are in heat-conducting contact with one another via heat transfer elements. Furthermore, the safety heat exchanger has a housing closed on all sides, which at least partially surrounds the piping systems and the heat transfer elements, in order to prevent an air exchange between the interior of the housing and the environment as far as possible. The housing has at least one gas-permeable pressure equalization opening for a permanent pressure equalization between the interior of the housing and the environment.

In other words, the safety heat exchanger is enveloped in a pressure-compensating manner. There is thus no completely gas-tight enclosure provided, even on the possibility of pressure measurement or pressure monitoring in the interior of the housing is omitted. On the contrary, a compensation of pressure differences between the interior of the housing and the surrounding area is possible via a permanently gas-permeable pressure equalization opening, for example in order to compensate for thermally induced pressure differences or to allow volumetric expansions in the evaporation of liquids in the interior which are not intended in the interior ( eg due to production or due to frost formation during operation). It is important that over the pressure equalization opening both an overpressure and a negative pressure in the interior of the housing relative to the environment is substantially balanced without a threshold to thereby avoid pressure loads of the sometimes problematic thermal conditions exposed housing (heat, cold), so that The housing has the required stability even with a simple and inexpensive construction. In addition, via the pressure equalization opening - to the required minimum extent - any resulting moisture, such as condensation moisture, escape and so the corrosion of the components of the safety heat exchanger can be reduced.

However, in comparison with known safety heat exchangers having sheaths which are open on one or more sides, a significantly improved heat transfer between the media in the piping systems is achieved since the heat exchange of the interior space with the environment is reduced to the minimum required. By the housing, for example, the emergence of a on the heat transfer elements and the piping along strike airflow - or even a convective airflow - prevented. Such an air flow would cause a significant heat loss and thus reduce the efficiency of the safety heat exchanger.

Advantageous embodiments of the invention are set forth in the subclaims, the description and the drawings.

According to one embodiment of the safety heat exchanger according to the invention, the heat transfer elements run parallel to one another along a respective main extension plane. The at least one pressure equalization opening is formed in this embodiment, for example, at a portion of the housing, which is arranged substantially parallel to the main extension planes of the heat transfer elements, typically at an end face of the housing.

For example, the heat transfer elements of the safety heat exchanger are plate-like elements which are arranged in parallel in a stack. When the pressure equalization holes on the parallel to the Extension planes of the plate-like elements lying housing sides are arranged, only the outer sides of the two outermost plates are flowed around by an air flow of the ambient air. An undesirable flow of air, in particular in the interior of the plate stack, can not arise in this way. However, a pressure equalization and a sufficiently good ventilation of the interior of the housing are still ensured.

However, the at least one pressure compensation opening may also be formed on another portion of the housing. In a particularly simple to implement embodiment, for example, a gap between two adjacent wall portions of the housing is formed, for. B. between a side surface and a lid portion of the housing, or between an end face and one or more side surfaces of the housing, or between a side surface and a bottom trough or bottom plate of the housing.

If only at a single portion of the housing (e.g., face or side surface) the at least one pressure equalization port is provided, and / or if only a single pressure equalization port is provided, a steady stream of air is particularly effectively avoided. This provides pressure equalization and adequate ventilation for most applications without undesirably high heat exchange with the environment.

It can be provided that the housing is formed by a pipe section, on whose end faces terminating elements are arranged. The pipe section has in particular a rectangular or circular cross-section. Such pipe sections are cost-effective construction elements which are well suited for the purpose described here. Both End elements may be, for example, cover-like elements which are inserted from the outside onto the pipe section. Another embodiment comprises a plate which is inserted into the tube section in order to close it and thus to form the housing closed on all sides.

In particular, it is preferred if the housing is at least partially formed by two or more layers of different or similar materials and / or the housing is at least partially made of plastic. Plastic-metal composites have proven to be particularly suitable. Parts of the housing - or the entire housing - may be formed by plastic foam.

The use of plastics and / or composite materials, which may be multi-layered, allows the cost-effective production of stable housing, which may have a number of other advantageous properties. By choosing suitable materials, the housing can, for example, also have a flame-retardant and / or current-insulating effect.

An embodiment of the safety heat exchanger according to the invention has a liquid collecting device, which is arranged in the operating position of the safety heat exchanger on the underside of the housing. Any resulting condensate or a leaking in a malfunction medium can be collected and discharged in a simple and safe way.

To facilitate the maintenance and inspection of the safety heat exchanger, a closable access opening may be provided which allows access to the interior of the housing. Such Access opening can be configured for example as a flap. It is also possible that this opening is formed by one or more side walls of the housing, which can be completely removed.

The housing may have a plurality of supply openings traversed by connection pipes for connecting the piping systems to a respective circuit of the respective medium or portions of the piping systems.

The invention is described below purely by way of example with reference to advantageous embodiments and with reference to the drawings. Show it:

Fig. 1 is a schematic perspective view of a heat exchange unit of a safety heat exchanger;

Fig. 2 is a side view of the heat exchange unit according to

Fig. 1;

3 shows a schematic perspective view of an embodiment of a safety heat exchanger according to the invention;

4a shows a schematic representation of an embodiment of the safety heat exchanger according to the invention with a housing having a circular cross-section; 4b and c are schematic representations of various embodiments of a front cover of the housing;

5 shows a cross section through an embodiment of the safety heat exchanger according to the invention;

6 shows a detail view of a section through an embodiment of the inventive safety heat exchanger.

Figure 1 shows a heat exchange unit 10 for heat exchange between two different media routed in separate piping systems. There is no fluid connection between the piping systems.

Each of the piping systems has an inlet 12 or 12 'and an outlet 14 or 14' for the respective media, which are arranged on an end face of the heat exchange unit 10. Connecting pieces 16 connect parallel pipes 22, 22 '(see FIG. 2) of the respective piping system to the end faces of the heat exchange unit, whereby the two media are guided past each other several times.

The tubes 22, 22 'of the piping systems are connected to each other with a plurality of juxtaposed heat conducting plates 18. The heat conducting plates 18 are made of a good heat conductor, such as metal, and thus contribute to the improved heat transfer between the piping systems of the safety heat exchanger. The heat-conducting plates 18 are arranged substantially plane-parallel. At the end faces of the heat exchange unit 10 are end plates 20 are provided, which form the respective end of the heat conducting plate stack. In the illustrated embodiment, the end plates 20 are made slightly thicker than the heat conducting plates 18, since they make a contribution to the stability of the heat exchange unit 10 in addition to their function as a heat conductor. The end plates 20 may also be made of a different material than the heat conducting plates 18 in order to better meet their support function.

Fig. 2 shows a side view of the heat exchange unit 10 according to Fig. 1. In conjunction with the perspective view of Fig. 1, the arrangement of the tubes 22, 22 'of the separate piping systems becomes clear. Each of the piping systems comprises eight tubes 22, 22 '. Of these eight tubes 22, 22 'are each two in Fig. 2 can be seen. Through the connecting pieces 16, 16 ', the tubes 22, 22' are connected in two groups, through which a respective medium flows.

The connection of the piping systems of the heat exchange unit 10 to a further line system (not shown) - for example to the piping system of a refrigeration system - via the inlets 12, 12 'and the outlets 14, 14'.

In order to improve the heat exchange between the different temperature levels of the media, the tubes 22, 22 'in a regular arrangement - in this embodiment, in an orthogonal grid of 4 x 4 tubes 22, 22' - led past each other. Although the tubes 22, 22 'are in spatial proximity to one another, they are deliberately spaced apart from one another. The interspaces prevent interference of a pipeline system on the other piping system. Especially when using different rather, possibly chemically reactive media, this represents a significant security aspect.

Preferably, all components of the heat exchange unit IO made of metal, in particular made of copper or a copper alloy, wherein for the components and different materials can be used.

FIG. 3 shows a safety heat exchanger 24 whose heat exchange unit 10 is enveloped according to the invention by a housing 26 closed on all sides. Only the inlets 12, 12 'and outlets 14, 14' protrude from the housing 26. The illustrated embodiment of the safety heat exchanger 24 thus has a complete enclosure of the heat exchange unit 10. In special applications, it may be provided that the housing 26 encloses only certain parts of the heat exchange unit 10 on all sides.

The housing 26 has a revision flap 28, which allows access to the interior of the housing 26. This greatly simplifies the control and maintenance of the heat exchange unit 10.

As a pressure equalization openings for a permanent pressure equalization between the interior of the housing 26 and the environment with minimal exchange of air with the environment, the housing 26, for example, several ventilation slots 30 on. The ventilation slots 30 are arranged on end faces 32 of the housing 26. The end faces 32 extend substantially plane-parallel to the end plates 20 of the heat exchange unit 10. Since the end plates 20 extend over a majority of the area of the inner cross-section of the housing 26, no undesirable air flows are formed inside the safety heat exchanger. shear 24, which would cause a lowering of the efficiency of the safety heat exchanger 24 heat dissipation.

Instead of a slot-shaped pressure compensation opening 30, a circular pressure equalization opening can generally also be provided, for example. Furthermore, only a single pressure compensation opening 30 may be provided, and / or the pressure compensation openings 30 are provided on a single end face 32 or on a single other housing portion in order to avoid an unwanted continuous air flow.

Another embodiment of the safety heat exchanger 24 is shown in FIG. 4a. The housing 26 does not correspond in this case the basic shape of a cuboid, but has substantially a Hohlzylin- derform. That is, a tubular section having a circular cross-section forms the base of the housing 26 in which the heat exchange unit 10 is arranged, symbolically represented by parallel plates. Such a design is characterized by high functionality and cost-effective production. The ends of the tube section can be closed by covers 33 which are placed on the openings of the tube cylinder, as outlined in Fig. 4b. It is also possible to fill the two tube openings with a plastic foam or insert end plates 33a (see Fig. 4c) in the tube openings. For reasons of clarity, the illustration of the heat exchange unit 10 in the interior of the housing 26 has been dispensed with in FIGS. 4b and 4c.

As an alternative to a pressure compensation opening formed, for example, in the cover 33 or in the end plate 33a, the pressure equalization opening may be formed by a gap 31 between the housing 26 and the cover 33 (FIG. 4b) or the end plate 33a (Figure 4c) is formed along part or along the full circumference of the housing 26.

5 shows a cross section parallel to a heat conducting plate 18 of a cuboid safety heat exchanger 24. The two piping systems of the safety heat exchanger 24 are composed of the tubes 22 and 22 ', which are symbolized by circles or circles with an X. Clearly visible is the 4 × 4 matrix arrangement of the tubes 22, 22 '. The tubes 22 and 22 'are arranged alternately both in rows and rows.

In this embodiment, the housing 26 consists of a plurality of composite plates 34 which are interconnected by brackets 36. The underside of the housing 26 is formed by a bottom tray 38, which is provided for collecting condensation or possibly outflowing media. The floor pan 38 has a drain 40 for the controlled removal of the collected liquids.

The joints 39 between the composite panels 34 and / or the bottom plate 38 are not sealed gas-tight. The remaining openings provide the necessary pressure equalization between the interior of the housing 26 and the environment without any air exchange with the environment to an extent that would interfere with the heat exchange between the media carried in the tubes 22, 22 '.

The housing 26 is connected to the heat exchange unit 10 by support members (not shown). It can also be provided that individual heat conducting plates 18 and in particular the end plates 20 act as supporting elements. Preferably, a heat insulator is between the supporting elements of the heat exchange unit 10 and the housing 26 are arranged to minimize a conductive heat flow.

6 shows further details of the safety heat exchanger 24. A section of a section along a tube 22 is shown. The left end of the tube 22 is formed by the flange-shaped configured inlet 12. This is followed by a coupling piece 42, which extends through a through hole 44 through the composite plate 34 of the housing 26. In the outer space of the housing 26, the coupling piece 42 can be connected to other components of a system, which is associated with the safety heat exchanger 24.

The composite panel 34 is a polyurethane (PU) panel composed of an outer panel 34a, an inner panel 34b, and an insulating polyurethane layer 34c disposed therebetween. Such PU panels are characterized by high stability and a good insulation effect. The gap between the passage opening 44 and the coupling piece 42 is not hermetically sealed, since a gas-tight closure of the housing 26 is currently not provided.

Fig. 6 also shows an embodiment of the connection between the heat exchange elements and the piping systems of the safety heat exchanger 10. It is exemplified the connection between a face plate 20 and a heat conducting plate 18 and a pipe 22. To improve the thermal coupling, both the front plate 20 and the heat-conducting plate 18 have a base 19. The pedestals 19 of adjacent plates 18, 20 adjoin one another directly, so that a direct contact of the tube 22 with the ambient air is largely avoided. This represents an additional measure for increasing the efficiency of the safety heat exchanger 24. LIST OF REFERENCE NUMBERS

10 heat exchange unit

12, 12 'inlet

14, 14 'outlet

16, 16 'connector

18 heat conducting plate

19 sockets

20 face plate

22 pipe

24 safety heat exchanger

26 housing

28 access door

30 ventilation slot

31 gap

32 front side

33 lids

33a end plate

34 composite panel

34a outer panel

34b inner panel

34c polyurethane layer

36 clip

38 floor pan

39 fugue

40 outflow

42 coupling piece

44 passage opening

Claims

claims

1. A heat exchanger for heat exchange between at least two media, wherein each medium is associated with a separate piping system and wherein the piping systems are spatially spaced from each other and via heat transfer elements (18, 20) in heat-conducting contact with each other, wherein the safety heat exchanger is a Ge closed on all sides - Housing (26) which at least partially surrounds the piping systems and the heat transfer elements (18, 20), thereby to prevent an air exchange between the interior of the housing (26) and the environment as far as possible, wherein the housing (26) at least one gas-permeable Pressure equalization opening for a constant pressure equalization between the

Interior of the housing (26) and the environment has.

2. Safety heat exchanger according to claim 1, characterized in that the heat transfer elements (18, 20) along a respective

Main extension plane parallel to each other, wherein the at least one pressure equalization opening (30) on a portion (32) of the housing (26) is formed, which is arranged substantially parallel to the main extension planes of the heat transfer elements (18, 20).

3. Safety heat exchanger according to at least one of the preceding Anprüche, characterized in that the at least one pressure equalization opening is formed by a gap (31, 39) between two adjoining sections of the housing (26).

4. Safety heat exchanger according to at least one of the preceding claims, characterized in that only at a single portion (32) of the housing (26), the at least one pressure compensation opening (30) is provided.

5. Safety heat exchanger according to at least one of the preceding claims, characterized in that the housing (26) has only a single gas-permeable pressure equalization opening (31).

6. Safety heat exchanger according to at least one of the preceding claims, characterized in that the housing (26) is formed by a pipe section, at the

End sides end elements (33, 33a) are arranged, wherein the pipe section in particular has a rectangular or circular cross-section.

7. Safety heat exchanger according to at least one of the preceding

Claims, characterized in that the housing (26) at least partially by two or more

Layers of different or similar materials is formed.

8. Safety heat exchanger according to at least one of the preceding claims, characterized in that that the housing (26) consists at least partially of plastic.

9. Safety heat exchanger according to at least one of the preceding claims, characterized in that that the housing (26) is at least partially formed by a plastic foam.

10. Safety heat exchanger according to at least one of the preceding claims, characterized in that the housing (26) at least partially made of a plastic-metal

Composite material exists.

11. Safety heat exchanger according to at least one of the preceding claims, characterized in that the housing (26) has a liquid collecting device (38), which is arranged in the use position of the safety heat exchanger (10) on the underside of the housing (26).

12. Safety heat exchanger according to at least one of the preceding claims, characterized in that the housing (26) has at least one in particular closable access opening (28) which allows access to the interior of the housing (26).

13. Safety heat exchanger according to at least one of the preceding claims, characterized in that the housing (26) has a plurality of supply openings (44) which are traversed by connecting pipes (42) for connecting the piping systems with a respective circuit of the respective medium or portions of the piping systems ,