WO2015079391A1

WO2015079391A1 - A heat exchanger and a method of realising it

Info

Publication number: WO2015079391A1
Application number: PCT/IB2014/066359
Authority: WO
Inventors: Christian Orlandi
Original assignee: Ncr Logistica S.R.L.
Priority date: 2013-11-29
Filing date: 2014-11-26
Publication date: 2015-06-04
Also published as: ITPR20130098A1

Abstract

A heat exchanger comprising: - a first pipe (2) for the passage of a first fluid; - a solidified metal porous foam (4); The first pipe (2) comprises a plurality of sections which: - develop inside the foam (4); - are in series; - are integrated into a first portion of the first pipe (2), said first portion defining a single block, said single block being a single and not an assembled piece and being serpentine-shaped.

Description

DESCRIPTION

A heat exchanger and a method of realising it Technical field

The present invention relates to a heat exchanger and a method of realising it.

Background art

A heat exchanger is known comprising:

- a set of pipes operating in parallel;

- a block of solidified aluminium foam.

The central section of the pipes of the set is drowned in the block while the ends of the pipes project with respect to the block. The foam is applied hot in the fluid state and then solidifies.

A drawback of said construction solution is linked to the fact that the fluid which transits in the set crosses the foam block once only since the set of pipes operate in parallel. The various sections of pipes also deform during the step of drowning in the foam at high temperature. This also makes connection of the various pipes with an outlet manifold difficult, since the ends of the pipes are shifted with respect to the theoretical initial position.

Object of the invention

In this context, the technical task underlying the present invention is to propose a heat exchanger which obviates the drawbacks in the known art as described above.

In particular, an object of the present invention is to provide an exchanger able to assist the moulding of it.

A further object of the present invention is proposing a heat exchanger which allows thermal exchange to be optimised and leaks to be avoided. The technical task set and the objects specified are substantially attained by an exchanger, comprising the technical characteristics as set out in one or more of the accompanying claims.

Brief description of drawings

Further characteristics and advantages of the present invention will become more apparent from the following indicative, and hence non- limiting, description of a preferred, but not exclusive, embodiment of an exchanger as illustrated in the appended drawings, wherein:

- Figures 1 , 2 and 3 show three construction solutions of an exchanger according to the present invention;

- Figures 4 and 5 show two alternative solutions of components of an exchanger according to the present invention;

- Figures 6, 7 and 8 show further construction solutions according to the present invention;

- Figure 9 is a construction solution according to the present invention;

- Figurel O shows a construction solution wherein the component of figure 9 is repeated several times.

Detailed description of preferred embodiments of the invention

In the accompanying drawings, number 1 indicates a heat exchanger. The exchanger 1 comprises:

- a first pipe 2 for the passage of a first fluid;

- a solidified porous foam 4 comprising metal parts (metal foams as such are well-known in the technical sector and therefore not further described). The first pipe 2 comprises a plurality of sections 9 (separation between the sections 9 may also be fictitious) that:

- extend inside the foam 4;

- are in series;

- are integrated into a first portion of the first pipe 2. The first portion of the first pipe 2 defines a single block, said single block being a single and not an assembled piece. Opportunely at least a part of said first portion of the first pipe 2 is drowned in the foam 4. Said single block is serpentine- shaped. Opportunely, all the sections of the first pipe 2 which transit inside the foam 4 form part of said single block. Opportunely, a part of the first pipe 2 comprised between a zone of first entry of the first pipe 2 into the foam 4 and a zone wherein the first pipe 2 definitively exits from the foam (and does not enter it again) is a single block and is serpentine-shaped. Opportunely, the part of the first pipe 2 inside the foam 4 is serpentine- shaped. Opportunely, the part of the first pipe 2 inside the foam 4 extends with continuity.

The presence of a single block makes the exchanger 1 more reliable by minimising the risk of leaks. Furthermore, this allows quicker realisation of the exchanger 1 , avoiding the need for seal tests. Furthermore, it allows the possibility of cooling the single block in the foam melting step with greater manufacturing precision. Opportunely, pipes operating in parallel are no longer present in the foam 4.

The foam 4 exchanges heat with the first pipe 2, allowing heating or cooling of the first fluid which circulates in the first pipe 2. The foam 4 in turn exchanges heat with an operating fluid outside the first pipe 2 and with which it is in thermal contact. Preferably, said operating fluid is a current of air which strikes the foam 4 and allows it to cool. In this case, the exchanger 1 allows cooling of the first fluid by dissipating the heat into the external air. The operating fluid indicated above opportunely strikes the foam 4 externally and also extends inside it, exploiting the empty spaces generated by the porous structure. This assists exchange of heat between the operating fluid and the foam 4. Advantageously, the pores of the foam 4 have a width greater than 1 millimetre. Opportunely, the volume of empty spaces defined by the pores is comprised between 50% and 80% of the total volume occupied by the foam 4.

Opportunely, the exchanger 1 comprises means 5 which force the operating fluid (typically air) against said foam 4 to extract heat from the foam 4. Said means 5 are generally a fan.

Opportunely, the foam 4 which comes into contact with the first pipe 2 is a single block and not an assembly of several pieces. By way of non-limiting example, the foam 4 is shaped as a cylindrical body, possibly hollow (to define an annular element; in that case, the first pipe 2 extends into the thickness of the annular element). By way of example, the foam 4 could be shaped as a parallelepiped. In a preferred but non-limiting embodiment, the foam 4 is a solidified aluminium foam.

The plurality of sections 9 of the first pipe 2 may comprise a curvilinear section immersed in the foam and immovably connected to the foam 4. The foam 4 attaches to the curvilinear section 201 due to bonds which are generated with cooling and solidification of the foam 4 around the curvilinear section 201 .

As exemplified in Figure 1 or 6, said plurality of sections 9 of the first pipe 2 comprises a plurality of straight sections 7. At least two of said straight sections 7 are joined by the curvilinear section 201 cited above. The curvilinear section 201 is advantageously "U-shaped".

Opportunely, the two straight sections joined by said curvilinear section 201 are entirely contained in the foam 4.

Preferably, the first pipe 2 comprises a plurality of parallel sections 7, entirely immersed in the foam 4 and connected in pairs by corresponding "U-shaped" connectors 70 entirely immersed in the foam 4.

As exemplified in Figures 2, 3, 7, 8 at least one part of said curvilinear section 201 is serpentine-shaped (in particular spiral shaped) and identifies a plurality of consecutive spirals 200. Said spirals 200 extend with helical progression and wind around a common line. In the case of Figure 2, 3, 7, 8, said plurality of sections 9 is defined by various consecutive sections of the curvilinear section 201 (the interface between the various sections in this case could be entirely fictitious).

The serpentine (both if it extends parallel to a plane as in Figure 1 or 6 or if it extends in a spiral way) allows the travel of the first fluid inside the foam

4 to increase and therefore improves the thermal exchange permitted to the exchanger 1 .

Inside the foam 4 the first pipe 2 is a single block without connection junctions of consecutive sections of it. In the preferred embodiment, the first pipe 2 comprises an inlet section 202 and an outlet section 203 outside said foam 4. Between said inlet section 202 and said outlet section 203, the first pipe 2 is a single block without connection junctions of consecutive sections of it.

Preferably, the exchanger 1 comprises a second pipe 3. At least one section of the first and second pipe 2, 3 is surrounded by the foam 4. The first pipe 2 defines a first channel 20 of passage for the first fluid. The second pipe 3 defines a second channel 30 for the passage of a second fluid. Opportunely, the second fluid is hotter than the first fluid. The first and second channel 20, 30 run alongside each other. In the solution of Figure 5, the first and second channel 20, 30 are alongside each other, in the sense that they mutually engage. In the solution of Figure 4, the first and second channel 20, 30 are alongside each other, in the sense that the second pipe extends inside the first pipe 2. The first channel 20 is therefore in the interspace between the second pipe 3 and the foam 4. The second channel 30 extends inside the second pipe 3. There is therefore a pipe in pipe solution. Opportunely, the first and the second pipe 2, 3 are coaxial. The first and second fluid may be in co-current or counter-current.

As exemplified in Figure 10, the exchanger 1 comprises a modular structure 6. The modular structure 6 comprises a first group of modular elements 60, each of which comprises:

- a first conduit 601 from which said first pipe 2 extends and to which it returns;

- a second conduit 602 placed inside said first conduit 601 and from which the second pipe 3 develops and to which it returns.

In a solution not shown, the second conduit 602 could also not be inside the first conduit 601 .

The first pipe 2 between an initial section in which it moves away from the first conduit 601 and an end section in which it returns to the first conduit 601 has a winding trend. Opportunely, a development line of the first pipe 2 has successive loops which extend with opposite concavities (see Figure

9). At the end of the first pipe 2, the second pipe 3 projects outside the first pipe 2 to allow connection with the second conduit 602.

Opportunely, the first and the second pipe 601 , 602 are outside the foam

4.

The first and the second conduit 601 a, 601 b of one of said modular elements 60a are consecutive respectively to the first and to the second conduit 601 a, 601 b of the adjacent modular element 60b (see Figure 10). An object of the present invention is also a method of realising a heat exchanger 1 . Opportunely, said exchanger 1 may present one or more of the features described above.

The method comprises the steps of:

-drowning at least one part of a first portion of a first pipe 2 in a metal foam 4 in the fluid state (opportunely, the foam 4 is an aluminium foam);

- solidifying the metal foam 4.

The step of drowning at least one part of said first portion envisages drowning a plurality of sections 9 which are in series. The first portion is a single block realised in a single piece. The single block is serpentine- shaped.

The present invention has numerous advantages.

A first advantage is linked to the greater heat exchange offered by the exchanger. A further important advantage is linked to the greater construction simplicity, which prevents deformation of the pipes. A further important advantage is linked to allowing quicker assembly.

The invention as conceived is susceptible to numerous modifications and variants, all falling within the scope of the inventive concept characterised thereby. Furthermore all the details can be replaced by other technically equivalent elements. In practice, all the materials used, as well as the dimensions, can be any according to requirements.

Claims

1 . A heat exchanger comprising:

- a first pipe (2) for the passage of a first fluid;

- a solidified metal porous foam (4);

characterised in that said first pipe (2) comprises a plurality of sections (9) that:

- develop inside the foam (4);

- are in series;

- are integrated into a first portion of the first pipe (2), said first portion defining a single block, said single block being a single and not an assembled piece and being serpentine-shaped.

2. The exchanger according to claim 1 , characterised in that all the sections of the first pipe (2) which rest inside the foam (4) form part of said single block.

3. The exchanger according to claim 1 or 2, characterised in that said foam (4) is a solidified aluminium foam.

4. The exchanger according to any one of the previous claims, characterised in that said plurality of sections (9) of the first pipe (2) comprises a curvilinear section (201 ) immersed in the foam (4) and immovably connected to the foam (4).

5. The exchanger according to claim 4, characterised in that said plurality of sections (9) of the first pipe (2) comprises a plurality of straight sections (7); at least two of said straight sections (7) being connected by said curvilinear section (201 ), said curvilinear section (201 ) being "U-shaped".

6. The exchanger according to any one of claims 1 to 4, characterised in that said first pipe (2) comprises a plurality of parallel straight sections (7) immersed in the foam (4) and connected in pairs to corresponding "U- shaped" connectors (70) immersed in the foam (4).

7. The exchanger according to claim 4, characterised in that at least one part of said curvilinear section (201 ) is serpentine-shaped and identifying a plurality of consecutive turns (200).

8. The exchanger according to any one of the previous claims, characterised in that it comprises a second pipe (3), at least one section of said first and said second pipe (2, 3) being surrounded by foam (4); the first pipe (2) defining a first channel (20) of passage for the first fluid; the second pipe (3) defining a second channel (30) for passage of a second fluid; the first and the second channel (20, 30) running alongside each other.

9. The exchanger according to claim 8, characterised in that the second pipe (3) develops inside the first pipe (2).

10. A method of realisation of a heat exchanger (1 ) comprising the steps of:

- drowning at least one part of a first portion of a first pipe (2) in a metal foam (4) in the fluid state;

- solidifying the metal foam (4);

characterised in that the step of drowning at least one part of said first portion envisages drowning a plurality of sections (9) which are in series; said first portion being a single block realised in a single piece, said single block being serpentine-shaped.