WO2006120068A1

WO2006120068A1 - Heat exchanger

Info

Publication number: WO2006120068A1
Application number: PCT/EP2006/061143
Authority: WO
Inventors: Thorsten Kusnik; Wolfgang Nuiding; Adolf Feinauer
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2005-05-10
Filing date: 2006-03-29
Publication date: 2006-11-16
Also published as: RU2451886C2; CN101738104B; RU2007136932A; US20090020265A1; DE102005021610A1; EP1846714A1; CN101171491B; CN101171491A; CN101738104A

Abstract

A heat exchanger comprises at least two tube sections which are wound helically to form a spiral (1, 2, 3) and are arranged in an interlacing manner inside one another, for guiding a heat transfer fluid.

Description

heat exchangers

The present invention relates to a heat exchange with a helically wound into a helix pipe section. Such a heat exchanger is known from US 5 502 829. The coil is used in this known heat exchanger for guiding a refrigerant as a first heat transfer fluid and is arranged in a flow channel surrounded by an elongated housing through which air is conveyed as a second heat transfer fluid by means of a blower.

A problem of this known heat exchanger is that the helix obstructs the air flow only on a part of the cross section of the flow channel. In the free interior of the helix and possibly also between the exterior of the helix and the housing, higher flow velocities result than in the immediate vicinity of the helix, so that a large amount of air passes through the heat exchanger, without getting into closer thermal contact with the helices. Other parts of the air flow successively sweep along many turns of the coil and thereby heat up strongly, so that the efficiency of the heat exchange to the downstream end of the flow channel decreases sharply.

A more compact heat exchanger than the one mentioned above is described in US 3,524,329. In this heat exchanger, the tube carrying the refrigerant forms spirals in a plurality of planes oriented transversely to the flow direction of the air through the heat exchanger, which are connected in series and alternately have left-handed and right-handed directions of rotation. However, the production of this heat exchanger is much more expensive than that of the former, since it is not possible to continuously wind the tube onto a winding core.

A compact heat exchanger with spiral pipe sections through which the refrigerant flows in series is also disclosed in DE-OS 2 136 369. This known heat exchanger is formed of a provided with refrigerant channels, wound into a spiral band. The object of the present invention is to provide a compact, easily realizable heat exchanger and a method for its production.

The object is achieved on the one hand by a heat exchanger with a helically wound to a first coil first pipe section for guiding a first heat transfer fluid, in which the first coil and a wound from a helically wound second pipe section second coil are arranged nested and fluidically connected to each other.

On the other hand, the object is achieved by a manufacturing method of the above-defined heat exchanger in which a tube is wound around a first winding core to form the first coil, a slotted second winding core through which at least one slot inlet and outlet of the helix can happen is placed around the first helix, and from the same tube on the second winding core, a first helix surrounding the second helix is wound.

Preferably, the pipe sections of the two helices are integrally fluidly connected to a continuous helix.

In order to avoid a sharp kink of the tube in the transition from the first to the second helix, the two helices are preferably wound with opposite hand. In this case, preferably, the pipe sections of the two helices are connected to each other at a respective same end of the two helices.

Alternatively, the tube sections of the two coils may also be connected by a tube section extending between opposite ends of the two coils. In this case, the handedness of the two coils may be the same.

Furthermore, a third or even further helices may be provided, which are each nested with the first and the second helix. The production of the heat exchanger is particularly simple if the spirals running into one another have a cross-section that is constant in the longitudinal direction, so that the coils are formed, for example, in the shape of a circular cylinder or a parallelepiped.

In order to improve the efficiency of the heat exchanger, it may be desirable for the interleaved coils to have a longitudinally tapered, e.g. have truncated cross-section.

A free space inside the innermost helix can be used by placing an evaporation tray or dryer there.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. Show it:

Fig. 1 is a perspective view of a heat exchanger acc. a first

Embodiment of the invention;

Fig. 2 is a plan view of the heat exchanger of Figure 1 in the axial direction.

Fig. 3 is a perspective view of a modified embodiment of

Heat exchanger of Fig. 1;

4 is a perspective view of a third embodiment of the

heat exchanger;

5 shows an axial section through a fourth embodiment of the heat exchanger;

Fig. 6 to 11 stages of the production of the heat exchanger according to the invention; and

12 shows a stage of the production according to FIG. 10 in the heat exchanger of FIG. 4 The heat exchanger shown in Fig. 1 comprises three integrally formed from a metal tube formed in the form of a helical spring coils 1, 2, 3, which in the present embodiment coaxially to a longitudinal center axis M into each other and interleaved in this way and thus space and space saving very are arranged compactly. The illustrated coils 1, 2, 3 each have five turns to keep the drawing clear; In practice, the number of turns is generally larger, so that the dimension of the heat exchanger along the longitudinal center axis M is greater than transverse to this.

The coils 1, 2, 3 are surrounded by a housing 4 shown broken away in the figure, which serves to bundle a stream of air flowing along the coils 1, 2, 3. On the housing is anchored over four struts 5, only two of which are visible in the figure, a fan, which serves for driving the air flow through the housing 4. A not visible in the figure propeller of the fan is located on the side facing away from the viewer open back of the housing 4. A motor 6 of the fan is disposed in an inner cavity of the innermost helix 1 and thus constitutes a flow obstacle, the through the housing extending air flow forces to close closely to the helices 1, 2, 3 along.

An inlet connection for refrigerant is denoted by 7. From this inlet port 7, the refrigerant first reaches the inner coil 1, which has right-handed direction of rotation. A pipe section 8 forms a transition to the middle, left-handed helix 2. A corresponding transition from the helix 2 to the outer, right-handed helix 3 is located on the side facing away from the viewer side of the heat exchanger and is not visible in the Fig. The refrigerant exits the heat exchanger via an outlet port 9.

To clarify the structure of the heat exchanger, a plan view of the three coils 1, 2, 3 parallel to the longitudinal central axis M is shown in FIG. In this plan view, the pipe section 10 can be seen, which connects the helixes 2 and 3 at the end remote from the viewer of the arrangement.

A second embodiment of the heat exchanger is shown in Fig. 3, wherein the housing of this embodiment, which does not differ from that of the first embodiment, in the figure is omitted. Inside the innermost helix 1 is here a flat shell 11. If the heat exchanger is installed in a refrigerator, the shell 11 serves as an evaporation tray, ie it traps condensation, which flows from an evaporator of the refrigerator, and evaporates it with the help of passing through the heat exchanger airflow. In this configuration, therefore, it is not necessary to block the interior of the inner coil 1 by a blower motor or the like. With sufficient length of the coils but can be in the cavity of the inner coil quite well for both the fan motor and the shell 11 space.

Instead of the shell 11 or possibly also together with this, a dryer connected in series with the coils 1, 2, 3 may be accommodated for the refrigerant inside the coil 1.

In the illustration of Fig. 3 is located below the bottom of the shell 1 is between the bottom of the shell 11 and underlying lower rectilinear portions 12 of the inner coil an air gap, so that the lower portions 12 are flowed around over its entire circumference of air can. Alternatively, the shell 11 could also be attached directly to these lower portions 12, so that they can deliver the heat of the flowing therethrough refrigerant through the attachment directly to the shell 11.

Nested coils 1, 2, 3 acc. A third embodiment of the heat exchanger according to the invention are shown in Fig. 4. In this embodiment, all helices 1, 2, 3 have the same direction of rotation, and the helices are connected to one another in each case by an approximately axially extending pipe section 13 and 14, which in a substantially axial direction in a space between two helices 1, 2 and 2, 3 extends from one end of the heat exchanger to the other. The flow direction of the refrigerant relative to the longitudinal central axis M is the same here in all three coils 1, 2, 3. That is, when air flows through the heat exchanger in the direction of the arrow P and the terminals 7 and 9 as in the first embodiment as inlet and. Actuate outlet, all three coils 1, 2, 3 operate in countercurrent.

In this embodiment, the pipe sections 13, 14 can also perform a stabilization function for the helical arrangement, by possibly via a thermally insulating intermediate layer, are attached to the windings of one of the two coils between which they extend, or on both coils.

Fig. 5 shows an axial section through the helices of a heat exchanger gem. A fourth embodiment of the invention, wherein lying above the cutting plane sections of the helices are each shown as dotted outlines. The helices 1, 2 here run on conical surfaces, i. the diameter of their turns decreases from one longitudinal end of the heat exchanger to the other. The advantage of this arrangement is that if one, when air flows parallel to the longitudinal central axis through the coils, all turns, including those at the downstream end of the heat exchanger, are flowed through by air, which is not already preheated to another turn.

A method for producing the heat exchanger according to the invention will be explained with reference to FIGS. 6 to 11.

Fig. 6 shows a cylindrical winding core 15 and a supply roll 16 of a thin-walled metal pipe, e.g. made of copper. A free end of the metal tube is temporarily fixed to the surface of the winding core 15. By simultaneously rotating the winding core 15 and moving the supply roll 16 along the winding core 15, metal pipe is unwound from the supply roll 16 and wound on the winding core 15 in evenly spaced turns, as shown in FIG. Thus, the helix 1 is obtained.

After the helix 1 is completely produced, a second winding core 17 in the form of a longitudinally slotted sleeve in the axial direction on the first winding core 15 and the coil 1 is pushed, the free end of the tube protrudes through the slot 18, as in Fig. 8 see.

If, in the state of FIG. 9, the second winding core 17 is completely pushed onto the first 15, the pipe section 8, which connects the helix 1 to the supply roll 16, also extends through the slot 17.

Now both hubs 15, 17 are rotated together, and at the same time the supply roll 16 is moved to the hubs 15, 17 along back to their original position. In this way, as seen in Fig. 10, the second coil 2 is obtained. Now, as shown in Fig. 11, a third, also slotted winding core 19 is pushed onto the hubs 15, 17 and the helices 1, 2, in turn, the free end of the tube and the pipe section 10 through the slot 20 of the winding core 19th extend. By turning the hubs and moving the supply roll 19, the helix 3 is now generated on the winding core 19. Since this process proceeds in the same way as the winding of the coils 1 and 2, it is not shown in the figures. It is obvious that, if necessary, the number of hubs and the spirals produced thereon can be arbitrarily increased in principle.

When the desired number of coils is produced, the temporary attachment of the tube to the inner winding core 15 is released, and the hubs are pulled out.

The manufacture of a heat exchanger of the type shown in Fig. 4 proceeds to the stage of Fig. 9 as well as described above. Instead, however, as shown in Fig. 10, to begin immediately with the winding of the coil 2 with opposite handedness, the tube is, as shown in Fig. 12, retracted in the slot 18 of the winding core 17 over the entire length of the coil 1 to form the portion 13 described with reference to Fig. 4, and then the coil 2 is wound with the same handedness as the coil 1. For all other spirals proceed in the same way.

Claims

claims

1. Heat exchanger with a helical to a first coil (1) wound first pipe section for guiding a first heat transfer fluid, characterized in that the first coil (1) and a wound from a helically wound second pipe section second coil (2, 3) interleaved arranged and interconnected.

2. Heat exchanger according to claim 1, characterized in that the pipe sections of the two coils (1, 2, 3) are integrally connected.

3. Heat exchanger according to claim 2, characterized in that the two coils (1, 2) are wound with opposite hand.

4. Heat exchanger according to claim 2 or 3, characterized in that the pipe sections at a same end of the two coils (1, 2, 3) are interconnected.

5. Heat exchanger according to claim 2 or 3, characterized in that the pipe sections by a pipe section (13, 14) are connected, which extends between opposite ends of the two coils (1, 2, 3).

6. Heat exchanger according to one of the preceding claims, characterized in that it comprises at least a third coil which is interleaved with the first and the second coil.

7. Heat exchanger according to one of the preceding claims, characterized in that the coils (1, 2, 3) are concentrically nested.

8. Heat exchanger according to one of the preceding claims, characterized in that the helices (1, 2, 3) have a longitudinal cross-section which is constant in the longitudinal direction.

9. Heat exchanger according to one of the preceding claims, characterized in that the helices (1, 2) have a longitudinally tapering cross-section.

10. Heat exchanger according to one of the preceding claims, characterized in that in the interior of the innermost helix (1), an evaporation tray (11) or a dryer is arranged.

A method of manufacturing a heat exchanger according to any one of the preceding claims, wherein a pipe is wound around a first winding core (15) to form the first helix (1), a slotted second winding core (17) around the first helix (1 ) is placed, and from the same tube on the second winding core (17) a first coil (1) surrounding the second coil (2) is wound.