WO2011057594A1

WO2011057594A1 - Pipe-in-pipe heat exchanger

Info

Publication number: WO2011057594A1
Application number: PCT/DE2009/001583
Authority: WO
Inventors: Dirk Zimmermann
Original assignee: Az Vermögensverwaltung Gmbh & Co. Kg
Priority date: 2009-11-11
Filing date: 2009-11-11
Publication date: 2011-05-19

Abstract

The invention relates to a pipe-in-pipe heat exchanger comprising a first outer pipe, a second inner pipe, and a connecting means with which both pipes are connected such that the connecting means provides a line connection for both the first pipe and the second pipe.

Description

Tube-to-Tube Heat Exchanger The invention relates to tube-to-tube heat exchangers.

It is known that simple heat exchangers can be produced by arranging a tube with a smaller diameter in a tube having a larger diameter and allowing a heat-absorbing medium to flow in the interior of the one tube and a heat-releasing medium in the interior of the respective other tube. The tubes arranged coaxially with one another are gripped at both ends in one fitting. They can be flowed through by the respective media in the same or opposite direction. For the heat transfer is initially the nature of the inner tube relevant. The outer tube, on the other hand, with its larger surface usually leads to heat losses, which reduce the overall efficiency.

In the design of such a type of heat exchanger is first the so-called heat transfer coefficient as a criterion in the foreground. Another design criterion is the cost factor.

Embodiments are also known in which the coaxially juxtaposed tubes are gripped on one side in a fitting and are connected to leads, while on the opposite side the inner tube is slightly shortened while the outer tube is closed and thereby in gives the tubes an opposite flow. Such type tube-in-tube heat exchangers are often used within heat exchanger tanks, wherein the outer tube is flowed around by a further medium. The tube-in-tube heat exchangers described above have too small a surface area, which is why heat transfer from one medium to another is limited by the small surface area of the respective active tube.

CONFIRMATION COPY In order to improve this, proposals have been made, such as those contained in DE 44 20 756 A1, EP 0 823 296 A2, US Pat. No. 5,054,196 and GB 12 94 400 A. However, the proposals in any case lead to a complicated and expensive production, whereby the cost of executed heat exchanger increase sharply.

According to a proposal in DE 10 2008 007 226 A1, a corrugated pipe is to be used as the heat exchanger tube. It should be inserted into the corrugated tube, a cylindrical tube of the shape that the inserted tube rests with its wall on the inside of the wave troughs of the corrugated tube. It is provided that the corrugated tube is helically corrugated and a heat exchange medium in the remaining cross sections, which form the wave crests, flows. As a result, there is a mismatch with regard to the flow cross sections, which deteriorates the effectiveness of this type of heat exchanger, at least when used with media of the same physical state.

A proposal in DD 247 965 A1 provides to arrange tube-in-tube heat exchanger with an outer corrugated pipe in a larger container several times. In this case, the corrugated tube is to be flowed around by a medium, while coaxially in the corrugated tube, a cylindrical tube is arranged and the opposite line strands represents the flowing medium in the corrugated tube. This arrangement can only be used in a serving as a heat exchanger container.

According to a proposal in DE 103 27 602 A1 it should be possible, inter alia, to operate a working according to the evaporator principle geothermal probe so that two corrugated tubes are coaxially arranged one inside the other, wherein the corrugated tube with the smaller cross section of the supply of condensed medium, while the outer Corrugated pipe with the larger cross-section to absorb the transferred into the gaseous state heat transfer medium. The heat exchange takes place via the wall of the outer corrugated tube, while the inner corrugated pipe, the heat exchange has rather minor importance.

According to DE 36 02 608 A1, an arrangement consisting of two corrugated tubes arranged coaxially with one another is to be designed in such a way that an inner corrugated tube is positioned in an outer corrugated tube in such a way that both Form the identical wave profile a gap-like gap with longitudinally approximately meandering course. Due to the frequent deflections, a particularly strong swirling of the flowing medium is to be achieved in conjunction with the frequent deflections of the media flow and thus a high degree of conversion efficiency. A disadvantage of this solution is that a narrow meander-shaped gap is always set, thereby inevitably resulting in a reduced volume flow. If there is a heat-carrying medium in the inner tube, only a part of the transported heat energy can be absorbed in the surrounding gap. Ultimately, a correspondingly high conversion efficiency can only be achieved by a larger overall length. This inevitably increases the cost of this type of heat exchanger. At the same time, however, due to the design, the flow resistances in the gap also increase with greater length, so that any extension of the heat exchanger is also ruled out. An optimization of the parameters, this solution is not available borrowed.

The tube-in-tube heat exchangers described above are useless because of their low efficiency, cause an increased manufacturing and thus cost or can only be used inside larger than heat exchangers used container.

However, in certain applications, especially where large amounts of heat are not to be recovered, there is a need for simple and highly efficient heat exchangers. However, this requirement can not be met by the tube-in-tube heat exchangers described in the prior art.

It is therefore an object of the invention to provide a highly efficient tube-in-tube heat exchanger, which is easy and simple to manufacture, can be manufactured at low cost, with respect to its dimensions, connection types and performance parameters can be easily adapted to existing applications and otherwise can be used as a single unit for direct heat exchange. This object is achieved by a tube-in-tube heat exchanger having the features of the characterizing part of claim 1 or claim 2 in cooperation with the features of the preamble of these claims. Secondary and subordinate claims describe other embodiments of the tube-in-tube heat exchanger according to the invention.

Hereinafter, terms used in the description with the following meaning are used:

Pipe is a finite section of a rigid or flexible pipe.

First pipe is the outer pipe of a pipe-to-pipe heat exchanger.

Second tube is the tube arranged in the interior of the first tube.

Corrugated pipe is a pipe or hose with a wave-shaped profiled wall, wherein the profiling can be parallel or spiral.

Anschlussstück- is a component or a structural unit, the first and second tube can close tightly at the tube ends and each tube cross sections each provides a connection area available. Verschlussstück- is a component or a structural unit which is adapted to close the pipe end of the first tube tight.

According to the invention, a tube-in-tube heat exchanger is designed so that its second, internal tube is designed as a corrugated tube.

It is assumed that this is compared to the known use of smooth tubes favorable for the heat exchange enlarged surface is present. Next it is assumed that due to the property a corrugated tube to produce turbulence and thereby develop an increased flow resistance, a more intense heat exchange can be achieved, while the media flow can be ensured in itself by appropriate dimensioning of the tube cross-sections.

Another feature of the tube-in-tube heat exchanger according to the invention is that they can be dimensioned according to the technical tasks to be solved. In terms of their structure, they are limited to a few starting materials, require no special technologies, can even be produced by hand and are therefore extremely inexpensive to produce.

Thereafter, the tube-in-tube heat exchanger according to the invention consists of a first tube and a second tube arranged in the interior of the first tube. First and second tube are connected to each other at least at one end. The second tube is a corrugated tube and provides for an intense heat transfer through the turbulence occurring in the region of its wall in the flowing medium. The outer diameter of the second tube is smaller than the inner diameter of the first tube, whereby the assembly of the tube-in-tube heat exchanger according to the invention is considerably facilitated. With regard to the choice of the dimensions of the first and the second tube, there is considerable freedom of choice with regard to the diameter ranges and also with regard to the lengths to be selected. Forced interactions of the medium between the two tube walls are largely avoided in the interest of a high degree of conversion.

In one embodiment of the tube-in-tube heat exchanger according to the invention, a second tube is first brought to a finite length. This is subsequently tightly connected to a connector. Then, a first tube is cut to a finite length and then also connected to a connector. On the opposite side, the two pipe ends are also connected to a connector. In the production of the tight connection with the fittings at the same time takes place the spacing of the second tube relative to the first tube. Appropriately - but not necessarily - is a coaxial arrangement.

Another embodiment of the tube-in-tube heat exchanger provides for using a shortened second tube and sealingly connecting the first and second tubes to a fitting. The second tube is shortened compared to the first tube, so that at the opposite end an overflow area between the two tubes is formed. The tube end of the first tube is sealed with a closure piece. This results in the possibility to supply a medium via one of the connections of the connection piece, to redirect the medium flow at the end opposite the connection piece of the tube-in-tube heat exchanger and return it to the connection piece and continue it via the second existing line connection.

It is also possible to close the protruding first tube by deformation. This can for example be done so that a winding closure is performed at the end of the first tube.

Likewise, by casting compounds, reactive resins, soldering or welding a closure of the pipe end can be performed.

The first tube is preferably a smooth tube, but may also be designed as a corrugated tube. It may also be made of metallic materials, plastics, which may also be fiber or fabric reinforced, glass or ceramic materials, made of vulcanizable materials, also with fabric reinforcement, or as a multi-layer structure of the aforementioned materials. Likewise, jacketed textile structures in tubular form may be used.

Another embodiment provides additional insulating material or a coating for insulation on the first tube. The fitting of the tube-in-tube heat exchanger is characterized in that it forms two separate spaces in its housing, each having connection to one of the two tubes. The connection areas to the first and the second pipe are approximately concentric to one another. The connection between the connector and the first and the second tube can be carried out in any way. It can be carried out both a compound using soft seals, a cutting or pressure ring connection, a cohesive connection or an adhesive bond.

On the connection side, each housing chamber is connected to an incoming or outgoing line area or to a collecting space for the medium.

In general, the connection piece will have a connection possibility for the first pipe, this connection preferably being led out laterally and having a connection possibility for the second pipe, which is preferably led out axially.

Another embodiment of the connector provides to provide an axial bore in the region of the introduced second conduit into which subsequently the second conduit can be inserted. This is already pre-assembled in this case and carries at its ends cylindrical connecting pieces, which close the axial bores during installation of the second tube or are additionally sealed.

Another embodiment provides a device for influencing one or both media streams. The influence can extend to the shutting off of one or both line channels. This can be influenced by valves, taps or valves. Furthermore, the influence can be done manually or with auxiliary power, also by influencing due to control signals from external devices. The invention will be explained in more detail below with reference to embodiments. Showing:

Fig. 1 - the basic arrangement for the tube-in-tube heat exchanger according to the invention.

Fig. 2 is a sectional view of one end of the tube-in-tube heat exchanger and the connection means. Fig. 3- an embodiment of a one-sided tube-in-tube heat exchanger.

4 shows an embodiment of the tube-in-tube heat exchanger having a plurality of second tubes within a first tube.

Fig. 5- an embodiment with a flexible first tube.

A connection means 1 is designed so that it forms a concentric duct 2, which is currently guided. A second conduit is arranged as collecting space 3 around the conduit 2 around and is connected via a connection 4 with conduit systems.

At the front side 5 of the connection means 1, a second corrugated tube 6 is connected by a soldering 7 or welding to the connection means. A first line 8 is also connected to the front side 5 of the connection means 1 by soldering or welding. It can also be other forms of connection, in particular detachable, executed.

At the opposite side of the pipe-in-tube heat exchanger a similarly constructed connection means is present.

Another embodiment of the tube-in-tube heat exchanger provides to connect the first tube 9 with a housing 10 and to produce a separate unit. Another separate unit is generated by the connection of a second corrugated tube 11 with a nozzle 12. Subsequently, this assembly is inserted through a cylindrical bore 13 in the housing 10 and the nozzle 12 sealed from the housing 10.

For a unilaterally connected tube-in-tube heat exchanger, the connection side is designed as described above.

At the opposite end 14, a second tube 15 is shortened and opposite the gap 16 between the first 17 and second tube 15 open. Preferably, therefore, the flowing medium first flows through the second tube 15 and passes at the exit point 18 into the intermediate space 16 between the first 17 and the second tube 15.

The first tube 17 is designed to project over the second tube 15, wherein it is closed at its end face 19. This can be done for example by squeezing and a subsequent soldering or welding process. Furthermore, any kind of tight closure is possible.

In order to be able to obtain the required heat energy from flowing media, several second tubes 21 can also be arranged within a first tube 20. The first tube 20 in this case has a larger diameter and the connecting means 22 is equipped with a larger collecting space 23.

Finally, in a further embodiment, the first tube 24 is a flexible tube and the second tube 25 is a corrugated tube, whereby a tube-in-tube heat exchanger of this kind is no longer connected to a linear line guide. If the flexible hose consists of a suitable material with increased thermal insulation, at the same time the heat losses via the first tube 24 can be reduced. In order to further reduce the losses, the first tube 24 in each of the embodiments described above may be additionally insulated by a heat-insulating sheathing.

The invention thus has the advantage that it makes it possible to produce in a simple manner with a limited number of components tube-in-tube heat exchangers, which can be adjusted in terms of their dimensions in a wide range of existing requirements.

LIST OF REFERENCE NUMBERS

1 connection means

2 line channel

3 collection room

4 connection

5 Front side of the connection means [1]

6 Second corrugated pipe

7 soldering

8 First line

9 First pipe

10 housing

1 1 Second corrugated tube

12 nozzles

13 hole

14 Opposite end

15 second tube

16 space

17 First pipe

18 exit point

19 front side

20 First pipe

21 Second pipe

22 connection means

23 collection room

24 First pipe

25 second pipe

Claims

claims

A tube-in-tube heat exchanger having a first tube and a second tube disposed in the interior of the first tube, wherein the first and second tubes are connected together at least at their ends, characterized in that the second tube is a corrugated tube and its outer diameter is smaller than the inner diameter of the first tube, so that it is insertable into the first tube, wherein the first and second tube at least at their ends spaced from each other, the shape that the wave profile of the second tube has a distance from the wall of the first tube and in cross-section, a free flow is possible.

2. tube-in-tube heat exchanger having a first tube and a second tube arranged in the interior of the first tube, wherein first and second tube are connected to each other at least at one end, characterized in that the second tube is a corrugated tube and its outer diameter is smaller than the inner diameter of the first tube so that it can be inserted into the first tube, wherein the first and second tubes are spaced apart at one end, the shape that the wave profile of second tube has a sufficiently large distance from the wall of the first tube, and in cross-section, a free flow is possible. the first tube is closed at the opposite end with a closure piece and results in a transition region between the flow channel formed by the second tube and the flow channel formed by the first tube.

3. tube-in-tube heat exchanger according to one of claims 1 or 2, characterized in that the first tube of metallic materials, plastics, also fiber or fabric reinforced, glass or ceramic materials, vulcanized materials with reinforcement or from a Multilayer structure of the aforementioned materials.

Pipe-in-tube heat exchanger according to one of claims 1 to 3, characterized in that at the ends of a connector has a connection option for the second tube and a connection option for the first tube and connection side of the second tube leading line path rectilinear or angled and the conduction path to the first tube straight and laterally offset from the center axis or angled out.

5. fitting for a tube-in-tube heat exchanger according to one of claims 1 to 4, characterized in that the connecting piece is made in two parts and a connecting piece which has a connection to the second tube, in a recess in the housing of the connecting piece can be introduced and the housing of the connector forms the conduit path for the first tube.

6. closure for a tube-in-tube heat exchanger according to claim 2, characterized in that a closure piece closes the pipe end opposite the connecting piece or the same is tightly closed by deforming the tube end of the first tube and gluing or soldering or welding.

7. tube-in-tube heat exchanger according to one of claims 1 to 4, characterized in that the first tube is a smooth tube or a corrugated tube.

8. tube-in-tube heat exchanger according to one of claims 1 to 4, characterized in that the first tube is provided with an additional insulating coating.

9. tube-in-tube heat exchanger according to one of claims 1 to 4, characterized in that in the connection piece a device for influencing the media flow / the media streams in one or both ducts is present.