WO2006063840A1

WO2006063840A1 - Heat exchanger

Info

Publication number: WO2006063840A1
Application number: PCT/EP2005/013548
Authority: WO
Inventors: Hansen Uwe
Original assignee: Neue Energie-Verwertungsgesellschaft Mbh
Priority date: 2004-12-18
Filing date: 2005-12-16
Publication date: 2006-06-22
Also published as: MA29102B1; JP2008524543A; PL1672304T3; DE502004004210D1; MX2007007366A; ES2289419T3; BRPI0519525A2; CA2590569A1; ATE365900T1; CN101080605A; RU2007127415A; WO2006063840A8; AU2005315782A1; IL183988A0; KR20070094792A; EP1672304A1; PT1672304E; TNSN07230A1; EP1672304B1; ZA200705222B

Abstract

The invention relates to a heat exchanger for transferring heat between two media, comprising: a jacket tube (8) that has an inlet (1) and an outlet (2) for a medium to be cooled; an inner tube (3), which is situated inside the jacket tube (8), is closed on the side facing the inlet (1), is joined to a coolant inlet (5) on the side facing the outlet (2), and has a coolant outlet. This coolant outlet leads to the side facing the outlet (2) of the inner tube (3) and transitions into a spiral line (7) which, from the side facing the outlet, extends toward the inlet (1) while winding around the inner tube (3) and, in the end, leads into a coolant discharge (10).

Description

heat exchangers

The invention relates to a heat exchanger for heat transfer between two separate media.

Heat exchangers are often used in technology to realize a heat transfer between two media. So to be processed with heat exchangers media either heated or cooled.

A field of application for heat exchangers is the cooling of hot gases. For example, in the area of internal combustion engines, exhaust gases are expelled from the combustion chambers at temperatures of 1000 ° C. and more. In some cases it is desirable to cool these hot gases to temperatures of 50 ° C and less. Here, heat exchangers are typically used. In certain situations, where the space is cramped or where it is necessary for other reasons, to realize the exchange of heat on the shortest possible distance, heat exchangers of small or short design are desired.

From the state of the art, no heat exchangers are known, which are particularly suitable for generating a high temperature gradient over the shortest distance (eg cooling of Hot gases from an inlet temperature of 1000 ° C and more to an outlet temperature of below 80 ° C, preferably below 50 ° C over a length of about 30 cm).

It is therefore an object of the invention to provide a heat exchanger, which can achieve a high heat transfer efficiency in a compact design.

This object is achieved with a heat exchanger having the features of claim 1. Further advantageous structural embodiments of the heat exchanger are specified in claims 2 to 7. In claim 8, a preferred use of the heat exchanger according to the invention is called, but not an exclusively possible use.

The heat exchanger according to the invention is characterized by a lying within a jacket tube inner tube, which is closed on one side. The closed end of the inner tube is located on the inlet side of the jacket tube, in which, for example, to flow cooled hot gases or other hot media. A coolant is first fed into the inner tube and cools both on the closed end face and on the pipe wall flowing past, to be cooled medium. From the inner tube, the cooling medium then passes into a spiral conduit wound around the inner tube and also leads there to a further cooling effect, before it leaves the heat exchanger.

In this way, a contact surface which is significantly enlarged in comparison with conventional heat exchangers is initially provided, at which contact takes place separately between the cooling medium and the medium to be cooled via the walls of the inner tube or the spiral line. In addition, this constructive embodiment, in which the medium to be cooled initially flows against the end of the inner tube closed at one end and then flows laterally along the spiral tube, causes turbulence of the medium to be cooled Whirling partly also against the actual main current runs. This results in a particularly long dwell time or a long migration path of the medium to be cooled in the heat exchanger, so that on a short construction section of the heat exchanger, an intimate contact between the medium to be cooled and the medium flows through the elements inner tube and spiral line results. This fact eventually leads to a considerable cooling can be achieved on a short longitudinal extent of the heat exchanger.

Of course, the heat exchanger according to the invention is also suitable to reverse to heat a cool, flowing into the casing medium with the aid of a flowing into the ^"coolant" 'inlet heating medium. In that regard, the terms "refrigerant inlet", "coolant telauslass" and " Coolant drain "not limited to a coolant to understand, but they can just as well be used for a medium which are used to heat a flowing through the jacket tube medium, thus a" warming agent ".

An outlet pipe to be provided in accordance with claim 2 in the interior of the inner tube has the advantage that the coolant flowing into the inner tube must be distributed throughout the inner tube before it can pass into the spiral conduit through the outlet tube. In this way, the achieved on the wall of the inner tube cooling effect is enhanced, resulting in an overall better cooling performance and heat transfer performance of the heat exchanger. Of course, similar considerations apply to operation of the heat exchanger for heating a medium.

The formation of the closed side of the inner tube as a baffle plate leads to an already occurring on this geometry first turbulence of the inflowing medium, which in total to the long residence time of the inflowing medium in the heat exchanger and thus achieved effi contributes to the high heat exchanger efficiency of the heat exchanger.

Also contributes to a high heat exchanger efficiency provided in accordance with claim 4 further that the spiral conduit is guided at least along the entire length of the inner tube surrounding it. Preferably, the individual turns of the spiral line are closely wound, but without touching. There must be a spacing between the individual turns of the spiral line so that contact can also take place between the medium to be cooled or heated and the surface of the spiral line through which the coolant or heat medium flows.

An embodiment as set forth in claim 5, wherein the spiral duct is arranged at a radial distance to the wall of the inner tube and to the wall of the jacket tube, supports the desired turbulence of the flowing through the jacket tube medium and the associated increased heat exchange efficiency. It has been found that a radial distance of the spiral conduit to the wall of the inner tube, which is approximately equal to the radial distance of the spiral conduit to the wall of the jacket tube, shows particularly good results (claim 6).

Finally, according to claim 7, it is advantageous if at least the spiral duct of the heat exchanger consists of a material with good thermal conduction properties. In this case, copper is preferably used, but other materials with good thermal conductivity properties are conceivable, such as, for example, silver.

Preferably, the heat exchanger according to the invention is used to cool combustion gases from internal combustion engines, in particular combustion exhaust gases from motor vehicle engines. Especially in motor vehicle engines or in the exhaust system of motor vehicle engines, such a heat exchanger must, on the one hand, apply a high cooling capacity in order to achieve Wa 1000 ° C and more emerging from the combustion chamber, hot exhaust gases to a temperature of 8O ⁰ C and less, preferably below 50 ° C to cool. The heat exchanger must also be of compact design, since the space in the exhaust system of the motor vehicle is limited. Here, the heat exchanger according to the invention is particularly well.

Further advantages and features of the heat exchanger according to the invention will become apparent from the following description with reference to the accompanying figure. It is in

Fig. 1 shows schematically a cross section through a heat exchanger according to the invention.

In the figure, a heat exchanger 12 according to the invention is shown schematically in cross section. The heat exchanger 12 according to the invention has a jacket tube 8, which opens via radial tapers in an inlet 1 shown in the drawing above and an outlet 2 shown in the drawing below. This embodiment of the heat exchanger 12 is preferably designed for the cooling of hot gases. However, the heat exchanger according to the invention can be used in all possible variants, including for cooling liquids, for heating gases or liquids or other heat transfers.

In the interior of the jacket tube 8, an inner tube 3 is arranged concentrically to this, which is closed at its front side facing the inlet 1 shown in the drawing above. The closed end face of the inner tube 3 forms a baffle plate 11 for a medium flowing in via the inlet 1 into the heat exchanger 12, in particular gas. On the outlet 2 facing side of the inner tube 3, this has a coolant inlet 5, which is passed through the jacket tube 8 and connected to a coolant inlet 9. Inside the inner tube 3 there is an outlet tube 6, which is drawn to just before the baffle plate 11 and there has an opening. This opening The outlet tube 6 leads out of the inner tube 3 and goes into a spiral conduit 7, which in tight turns, but with retention of a distance between the turns, along the entire length of the inner tube 3 to this is led around. At the end of the spiral line this goes into a coolant outlet 10, which is passed through the jacket tube 8.

In a preferred operation for cooling hot exhaust gases from internal combustion engines, the hot exhaust gases enter the jacket tube 8 via the inlet 1. There they meet the baffle plate 11, whereby the stream is divided and first turbulences arise. This is indicated schematically in the figure by corresponding arrows. There on the baffle plate 11 already takes place a first indirect contact with the flowing in the inner tube 3 cooling medium, so that already an initial cooling effect is effected. After the incoming hot medium, preferably the gas is deflected by the baffle plate 11, it enters the annular space formed between the casing tube 8 and the inner tube 3. In this annular space is the spiral conduit, which is arranged in this embodiment in the radial direction approximately centrally between the wall of the inner tube 3 and the wall of the outer tube 8. By the flow resistance formed by the spiral conduit 7 on the one hand as well as by between the fresh by flowing coolant comparatively cold wall of the inner tube 3 and the warmer walls of the already flowing through heated coolant spiral conduit 7 convection is flowing into the jacket tube 8 medium, preferably gas forced to vortex formation. This is indicated in the figure above right at the top two turns of the spiral conduit 7 by corresponding arrows. As a result of this turbulence, the inflowing medium, preferably gas, runs a markedly extended path within the jacket tube 8 and has intensive contact with the surfaces of the inner tube 3 and spiral conduit 7 which are traversed by the cooling medium. After passing through the entire length of the jacket tube 8 or the spiral conduit 7 and thereby experiencing vigorous turbulence, the cooled medium, preferably gas, exits through the outlet 2.

The flow of the coolant from the coolant inlet 9 through the inner tube 3 and the spiral conduit 7 up to the coolant outlet 10 is also indicated by arrows.

In the illustrated embodiment of a heat exchanger according to the invention, the inner tube 3 has a diameter d of 60 mm, the diameter of the spiral line d _s , measured from outer wall to outer wall, is 110 mm, the diameter D of the jacket tube 150 mm, the length L of the jacket tube 200 to 300 mm, the diameter of the inlet 1 and the outlet 2 (not indicated in the figures) about 50 to 60 mm. A copper conduit is used as a spiral conduit 7 with a circular cross-section and a diameter of 15 mm.

This heat exchanger is used for cooling exhaust gases leaving about 1000 ° C. and more from an internal combustion engine up to temperatures of about 50 ° C. For this purpose, n-butane is added at room temperature (about 25 ° C) in the coolant inlet, the n-butane has then left the coolant outlet at a temperature of about 120 ° C. To promote the coolant n-butane, a 30 bar pump was used. Alternatively, instead of the n-butane, water or another liquid or a liquid mixture can also be used as the coolant.

Due to its dimensions, the heat exchanger according to the invention could be integrated into the exhaust system of a motor vehicle, for example as a replacement for a catalytic converter or a silencer.

As a positive effect of the drastic cooling of the exhaust gases, it was found that pollutants contained in the exhaust gas, which otherwise have to be withdrawn from the exhaust gas stream by means of complex catalytic converter technology, are expelled in the heat exchanger. len. This can be explained because the rapid cooling of the exhaust gases from the temperatures at which they exit the internal combustion engine to the dew point of water produces water. This water almost completely washes away the other harmful components contained in the exhaust stream. By the cooling of the exhaust gases to the dew point of the water resulting water, an additional cooling effect is generated, since the water can dissipate a proportion of heat.

Further, since all the gases expand by 1/126 when heated by 1 ° C and contract when the temperature is lowered, the gas becomes smaller in volume at a temperature difference of several 100 ° C. This has the consequence that the use of the heat exchanger according to the invention for cooling the resulting in an internal combustion engine of a motor vehicle exhaust gases, the noise emissions are almost completely reduced and the usual muffler can be omitted except for a rear muffler.

The heat exchanger according to the invention is not limited to the use described in this embodiment, but can be used for cooling or heating of various media. Thus, for example, it is conceivable to use a correspondingly larger proportions with similar proportions heat exchanger for cooling exhaust gases from power plants or industrial plants, whereby also here caused by the sudden cooling cleaning effect of the gases can be achieved.

But even without a cleaning effect, the heat exchanger can be used only for heat transfer.

In that regard, reference is made to the following claims with regard to the scope and scope of the invention, which alone limit the scope of the invention. LIST OF REFERENCE NUMBERS

1 inlet

2 outlet

3 inner tube

4 lower pipe end

5 coolant inlet

6 outlet pipe

7 spiral cable

8 casing pipe

9 coolant inlet

10 coolant drain

11 baffle plate

12 heat exchangers

D diameter

d diameter

diameter

L length

Claims

claims

1. A heat exchanger for heat transfer between two media with an inlet (1) and an outlet (2) for a medium to be cooled jacket tube (8), within the jacket tube (8) arranged inner tube (3), which on the inlet (1) facing side, is connected to the outlet (2) side facing a coolant inlet (5) and having a coolant outlet, which to the outlet

(2) facing side of the inner tube (3) and in a from there in the direction of the inlet (1) around the inner tube (3) spiraling spiral line (7) merges, which finally in a coolant outlet (10) opens.

2. Heat exchanger according to claim 1, characterized in that the coolant outlet (7) of the inner tube (3) is connected to a in the interior of the inner tube (3) to the inlet (1) facing side of the inner tube zoom led outlet pipe (6).

3. Heat exchanger according to one of claims 1 or 2, characterized in that the closed side of the inner tube forms a baffle plate (11) for via the inlet (1) in the jacket tube (8) inflowing, to be cooled medium.

4. Heat exchanger according to one of the preceding claims, characterized in that the spiral conduit (7) is guided at least along the entire length of the inner tube (3) surrounding it.

5. Heat exchanger according to one of the preceding claims, characterized in that the spiral conduit (7) is arranged at a radial distance from the wall of the inner tube (3) and to the wall of the jacket tube (8).

6. Heat exchanger according to claim 5, characterized in that the radial distance of the spiral conduit (7) to the Wall of the inner tube (3) is approximately equal to the radial distance of the spiral conduit (7) to the wall of the jacket tube (8).

7. Heat exchanger according to one of the preceding claims, characterized in that at least the spiral conduit

(7) consists of a material with good thermal conductivity, preferably of copper.

8. Use of a heat exchanger according to one of claims 1 to 7 for the cooling of combustion exhaust gases from internal combustion engines, in particular of combustion exhaust gases from motor vehicle engines.