Heat exchanger
A heat exchanger includes at least two tube sections wound helically to form a spiral and are arranged in an interlacing manner inside one another for guiding a heat transfer fluid. The heat exchanger includes a first tube section helically wound to form a first spiral. The first tube section is for guiding a first heat transfer fluid and a second tube section is helically wound to form a second spiral, the first spiral and the second spiral being arranged in an interlacing manner inside one another and being connected to one another.
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The present invention relates to a heat exchanger comprising a tube section which is wound helically to form a spiral. Such a heat exchanger is known from U.S. Pat. No. 5,502,829. In this known heat exchanger the spiral serves to guide a coolant as a first heat transfer fluid and is arranged in a flow duct surrounded by an elongated housing, through which with the aid of a fan air is conveyed as a second heat transfer fluid.
One problem of this known heat exchanger is that the spiral impedes the air flow only on a part of the cross-section of the flow duct. In the free inside of the spiral and possibly also between the outside of the spiral and the housing higher flow velocities are produced than in the immediate vicinity of the spiral so that a large quantity of air passes the heat exchanger without coming into closer thermal contact with the spirals. Other parts of the airflow pass in succession along many windings of the spiral and, in doing so, heat up intensely, so the efficiency of the heat exchange decreases sharply toward the downstream end of the flow duct.
A more compact heat exchanger than the aforementioned one is described in U.S. Pat. No. 3,524,329. In this heat exchanger, the tube which guides the coolant forms spirals, which are connected to one another in series and alternately exhibit a left-hand and right-hand direction of rotation, in a plurality of planes oriented perpendicularly to the direction of flow of air through the heat exchanger. The production of this heat exchanger is, however, substantially more costly than that of the first-mentioned heat exchanger, as it is not possible to wind the tube continuously onto one winding core.
A compact heat exchanger with spiral-shaped tube sections, through which the coolant flows in series, is also disclosed in DE-OS 2 136 369. This known heat exchanger is formed from a tape wound into a spiral fitted with coolant ducts.
The object of the present invention is to indicate a compact, easily implementable heat exchanger and a method for the production thereof.
The object is achieved firstly in a heat exchanger comprising a first tube section which is wound helically to form a first spiral for guiding a first heat transfer fluid, in which the first spiral and a second spiral which is wound from a helically wound second tube section are arranged in an interlacing manner inside one another and, in flow engineering terms, are connected to one another.
The object is achieved secondly in a method for the production of the heat exchanger defined above, in which a tube is wound around a first winding core so as to form the first spiral, a slotted second winding core, through the at least one slot of which the inlet and outlet of the spiral can pass, is placed around the first spiral, and from the same tube a second spiral surrounding the first spiral is wound on the second winding core.
The tube sections of the two spirals are preferably connected to one another in one piece, in flow engineering terms, to form a continuous spiral.
In order to avoid a sharp kink in the tube at the transition from the first to the second spiral, the two spirals are preferably wound with opposing handednesses. In this case, the tube sections of the two spirals are also preferably connected to one another at a same end of the two spirals respectively.
Alternatively, the tube sections of the two spirals can also be connected by means of a tube section which extends between opposite ends of the two spirals. In this case, the handedness of the two spirals can be the same.
Furthermore, a third or yet further spirals can be provided, which are respectively interlaced with the first and the second spiral.
Production of the heat exchanger is particularly simple if the spirals running into one another have a constant cross-section in the longitudinal direction such that the spirals are shaped e.g. in the form of a circular cylinder or a rectangular prism.
In order to improve the efficiency of the heat exchanger, it may be desirable for the spirals arranged in an interlacing manner inside one another to have a cross-section that tapers in the longitudinal direction, e.g. like a truncated cone.
A free space in the inside of the innermost spiral can be utilized by arranging an evaporation tray or a dryer there.
Further features and advantages of the invention will emerge from the description below of exemplary embodiments with reference to the attached drawings, in which:
The heat exchanger shown in
The spirals 1, 2, 3 are surrounded by a housing 4 shown in a cut-open manner in the figure, which housing serves to keep an airflow passing along the spirals 1, 2, 3 concentrated. Anchored to the housing via four braces 5, of which only two are visible in the figure, is a fan which serves to drive the airflow through the housing 4. A propeller (not visible in the figure) of the fan is located on the open rear side, facing away from the observer, of the housing 4. A motor 6 of the fan is arranged in an inner cavity of the innermost spiral 1 and consequently represents a flow obstacle which forces the airflow running through the housing to pass closely along the spirals 1, 2, 3.
An intake terminal for coolant is labeled 7. From this intake terminal 7 the coolant reaches firstly the inner spiral 1 which has a right-hand direction of rotation. A tube section 8 forms a transition to the central left-handed spiral 2. A corresponding transition from the spiral 2 to the outer, again right-handed, spiral 3 is located on the side of the heat exchanger facing away from the observer and is not visible in the figure. The coolant exits the heat exchanger via an outlet terminal 9.
To illustrate the structure of the heat exchanger,
A second embodiment of the heat exchanger is shown in
In place of the tray 11 or possibly also together with this tray, a dryer for the coolant connected in series to the spirals 1, 2, 3 can be accommodated inside the spiral 1.
In the diagram in
Interlaced spirals 1, 2, 3 according to a third embodiment of the inventive heat exchanger are shown in
The tube sections 13, 14 in this embodiment can also fulfill a stabilizing function for the spiral arrangement by being fastened, optionally via a thermally insulating intermediate layer, to the windings of one of the two spirals between which they extend, or even to both spirals.
A method for the production of the heat exchanger according to the invention will be explained with reference to
Once the spiral 1 has been generated fully, a second winding core 17 in the form of a longitudinally slotted sleeve is pushed in an axial direction on to the first winding core 15 and the spiral 1, the free end of the tube protruding through the slot 18, as can be seen in
When in the stage shown in
Both winding cores 15, 17 are now rotated together, and at the same time the delivery roll 16 is displaced along the winding cores 15, 17 back to its starting position. The second spiral 2 is obtained in this way, as can be seen in
Now, as shown in
When the desired number of spirals has been generated, the temporary fastening of the tube to the inner spiral 15 is detached, and the winding cores are extracted.
The production of a heat exchanger of the type shown in
Claims
1-11. (canceled)
12. A heat exchanger comprising:
- a first tube section helically wound to form a first spiral, the first tube section for guiding a first heat transfer fluid; and
- a second tube section helically wound to form a second spiral, the first spiral and the second spiral being arranged in an interlacing manner inside one another and being connected to one another.
13. The heat exchanger as claimed in claim 12, wherein the first tube section and the second tube section are connected in one piece.
14. The heat exchanger as claimed in claim 13, wherein the first tube section has a handedness in a one direction and the second tube section has a handedness opposite to the handedness of the first tube section.
15. The heat exchanger as claimed in claim 13, wherein the first spiral has an end, the second spiral has an end that coincides with the end of the first spiral, and the first tube section and the second tube section are connected to one another at the coinciding ends of the first spiral and the second spiral.
16. The heat exchanger as claimed in claim 13, wherein the first tube section and the second tube section are connected via an extension of one from the group of the first tube section and the second tube section that extends between opposite ends of the first spiral and the second spiral.
17. The heat exchanger as claimed in claim 12 and further comprising at least one third spiral interlaced with the first spiral and the second spiral.
18. The heat exchanger as claimed in claim 12, wherein the first spiral and the second spiral are interlaced concentrically.
19. The heat exchanger as claimed in claim 12, wherein the first spiral and the second spiral each has a constant cross-section in the longitudinal direction.
20. The heat exchanger as claimed in claim 12, wherein the first spiral and the second spiral each has a tapering cross-section in the longitudinal direction.
21. The heat exchanger as claimed in claim 12 and further comprising one from the group of an evaporation tray and a dryer arranged inside the innermost spiral of the first spiral and the second spiral.
22. A method for the production of a heat exchanger, the method comprising:
- winding a tube around a first winding core to thereby form a first spiral;
- placing a slotted second winding core around the first spiral; and
- from the tube, winding a second spiral on the second winding core in a manner resulting in the second spiral surrounding the first spiral.
Type: Application
Filed: Mar 29, 2006
Publication Date: Jan 22, 2009
Applicant: BSH Bosch und Siemens Hausgeräte GmbH (München)
Inventors: Adolf Feinauer (Giengen), Thorsten Kusnik (Bächingen), Wolfgang Nuiding (Giengen)
Application Number: 11/918,709
International Classification: F28D 15/00 (20060101); F28D 7/02 (20060101);