WO2010105884A1

WO2010105884A1 - Refrigeration device, throttle tube for a refrigeration device, and method for the production thereof

Info

Publication number: WO2010105884A1
Application number: PCT/EP2010/052024
Authority: WO
Inventors: Thomas Kranz; Holger Moch
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2009-03-19
Filing date: 2010-02-18
Publication date: 2010-09-23
Also published as: PL2409094T3; EP2409094A1; EP2409094B1; DE102009001677A1

Abstract

The invention relates to a refrigeration device, in particular a domestic appliance, having a refrigerant circuit (10), comprising a throttle element (2) in the form of a throttle tube, wherein the throttle tube comprises a metal tube (12) that is surrounded at least over part of the length thereof by a plastic layer (22). Thus, the throttle tube (2) can be in contact with a suction tube (4) of the refrigerant circuit (10) leading to a compressor (15) so that an energetically advantageous heat exchange can take place. The invention further relates to a co-extrusion method for coating a metal tube (12) with a plastic layer (22).

Description

Refrigeration appliance, throttle pipe for a refrigeration device and method for its production

The invention relates to a refrigeration device, a throttle tube for a refrigeration device, and a method for its production.

Refrigerating appliances extract heat from a room with a low temperature level, the interior of the refrigerating appliance, in order to dispense it in a room with a higher temperature level, as a rule in the space surrounding the refrigerating appliance. For this purpose, so-called refrigerants are used, which evaporate at low temperatures. The refrigerant circulates in a closed pipe system, the refrigerant circuit. In the conventional in domestic refrigeration compression system, the refrigerant circuit comprises an evaporator, a compressor (compressor), a condenser (condenser) and a throttle body. In the evaporator in the interior of the refrigerator, the refrigerant evaporates at low pressure and thereby deprives the interior of heat. The resulting gaseous refrigerant is led out of the interior and fed via a so-called intake manifold to the compressor, which compresses it and forwards the compressed and thus increased in its temperature refrigerant to the condenser. In the condenser, the refrigerant releases heat to the ambient air. The liquefied refrigerant then passes through the throttle body, in which the pressure is reduced in the evaporator. The refrigerant cycle starts again.

As a throttle body is usually used in household refrigerators a tube with a small diameter, in particular a copper tube. By contrast, the suction pipe leading to the compressor usually consists of aluminum, since it is formed in one piece with the evaporator.

For reasons of refrigeration and energy technology, a heat exchange between intake manifold and throttle tube is advantageous. The two tubes should therefore be in heat-conducting contact with each other as far as possible over at least part of their length. However, this is problematic because direct contact between aluminum and copper is not permitted for reasons of corrosion and due to standard specifications. It is therefore an object of the invention to produce a safe and production-compatible contact protection between the throttle pipe and intake manifold.

This object is achieved by the invention with a refrigeration device according to claim 1, a throttle tube according to claim 10 and a method for producing a throttle tube according to claim 15.

According to the invention, the throttle tube comprises a metal tube which is encased with a plastic layer over at least part of its length. The advantage of such a plastic layer is, on the one hand, that the plastic layer insulates the two tubes very well from one another electrically. Although plastic is not very thermally conductive, but the plastic layer is chosen to be sufficiently thin, still finds a heat exchange between the intake manifold and throttle pipe instead. In addition, the plastic layer is better corrosion resistant than, for example, a galvanically applied zinc layer. Finally, it is advantageous that the plastic layer can be easily removed from the pipe ends, for example by simply slitting and peeling, which requires no tool other than the fingernail. For connection reasons, the pipe ends of the throttle tube must be blank, so that the throttle tube can be mounted on the one hand at the injection point of the evaporator and on the other hand on a drying cartridge or at the outlet of the condenser.

Preferably, the metal tube of the throttle tube is made of copper or a copper alloy, since copper tubes are easy to manufacture and sufficiently flexible. The throttle tube is preferably about 30 cm to 3 m long and has an outer diameter of about 0.5-4 mm and an inner diameter of about 0.5-0.8 mm. By varying the length or the inner diameter of the throttle tube, the pressure loss to be achieved can be adjusted.

The plastic layer is preferably as thin as possible to produce. It preferably has a thickness of between 20 and 500 .mu.m, preferably between 50 and 300 .mu.m, more preferably between 100 and 200 .mu.m. This ensures that sufficient heat exchange takes place between the throttle tube and the suction tube in contact therewith. The plastic layer preferably comprises a thermoplastic or thermosetting plastic or consists entirely of such a plastic, such as PUR (polyurethane), PP (polypropylene) or PE (polyethylene). Particularly preferably, the plastic is extrudable, so that the plastic layer can be applied by co-extrusion on the throttle tube. Such a co-extruded coating can be easily removed without damaging the base material.

Particularly preferably, the plastic layer is doped with a thermally conductive additive material. For example, the plastic material used for the plastic layer graphite powder, less preferably metal powder are buried. The thermally conductive filler may also be zinc oxide, quartz, starch or talc.

The throttle tube is preferably in contact with at least a portion of its length in contact with a suction pipe leading to a compressor. In this case, a plastic layer arranged on the outside of the throttle tube touches the outside of the suction tube at least at one point, so that a thermal bridge is produced.

Particularly preferably, the section of the throttle tube which is in contact with the suction pipe runs parallel to a section of the suction pipe. It is also possible for the throttle tube to have a plurality of sections which run parallel to a section of the suction tube, namely in that the throttle tube passes through at least one hairpin curve and thus leads past one and the same section of the suction tube with two sections which guide the refrigerant in opposite directions becomes. Alternatively, it is also possible to lay the throttle tube or a section of the throttle tube in a spiral around the suction tube, so that the throttle tube is in touching contact with the suction tube in this spiral-shaped region over its entire length.

Preferably, the portions of the throttle tube and the suction tube in contact with each other are fixed to each other. The attachment can be done for example by a clamp or a suitable adhesive. Particularly preferably, the respective sections of the throttle tube and the suction tube are secured together by an adhesive tape. The adhesive tape is preferably aligned along the tube axes, so it is glued lengthwise and preferably extends at least substantially over the entire contacting portion of the throttle tube and the suction tube. The refrigerator is preferably a household refrigerator, in particular a refrigerator, a freezer or a fridge-freezer.

The invention is also directed to a throttle tube for a refrigerator, wherein the throttle tube comprises a metal tube, which is coated on its outside with a plastic layer. The throttle tube is preferably configured as described above.

Finally, the invention is also directed to a method for producing a throttle tube, comprising the following steps: providing a metal tube, in particular a tube made of copper or a copper alloy, and coating the outer side of the metal tube by co-extruding with a thermoplastic material.

The metal tube is made in a known manner, it may be made of copper or of a suitable copper alloy.

The metal tube is preferably in the form of endless goods, for example wound up on a roll. From there it is pulled as a soul through an extruder, which by co-extrusion encases the outside of the metal tube with a plastic or coated. The method is preferably carried out in a similar manner as in the sheathing of cables. After coextrusion, the coated metal tube is preferably once again wound onto a roll after the plastic layer has cured. Alternatively, the co-extruded product can already be tailored to individual throttle tubes.

The invention will be explained in more detail with reference to exemplary embodiments with reference to the accompanying drawings.

In the drawings show:

1 is a schematic representation of an inventively designed Kält- temittelkreislaufs a refrigeration device;

2 shows a cross section through the suction pipe and throttle pipe along the line AA of Fig. 1. Fig. 3 shows a cross section through the intake manifold and throttle tube, according to a first

Embodiment are attached to each other;

4 shows a cross section through the suction pipe and throttle pipe, which are fastened together according to a second embodiment.

Fig. 5 is a schematic representation of the manufacturing method according to the invention.

1 shows a refrigerant circuit of a refrigerant appliance, as used in particular for household refrigerators. In coils 14 of the evaporator 13, the refrigerant evaporates and thereby deprives the interior of the refrigerator heat. About the suction pipe 4, the evaporated refrigerant is supplied to the compressor 15. The compressed refrigerant flows through the coils 17 of the condenser 16, which is arranged for example on the rear wall or in a side wall of the refrigerator. Along the direction indicated by the arrow P flow direction, the liquefied refrigerant then flows through a dryer 18 through the throttle tube 2. This can be up to 2 to 3 meters long, which is why it is guided in snakes 2 'compact. Over a part L of its length, the throttle pipe 2 is guided in parallel and in touching contact with a corresponding portion of the suction pipe 4 leading to the compressor.

The length L, along which the suction pipe 4 and the throttle tube 2 are to be in physical contact, is for example 5 cm to 1 m, preferably about 20 to 40 cm.

The evaporator 13 is preferably a so-called "tube-on-sheet" evaporator, in which the tube coil 14 is mounted on a plate. In such evaporators, the heat exchange between the intake manifold 4 and the throttle tube 2, preferably by direct contact of both tubes.

FIG. 2 shows the suction pipe 4 and the throttle pipe 2 in contact therewith in cross-section. The suction tube 4 is typically made of aluminum or an aluminum alloy. The suction tube 2 according to the invention consists of a copper tube 12, which is covered with a plastic layer 22. In the example shown, the outer diameter of the copper tube 12 is about 1, 8 mm, the inner diameter of about 0.5 mm. The Plastic layer 22 with a thickness of about 0.2 mm is in touching contact with the suction pipe 4. At one end 11 of the suction pipe, this is connected to the evaporator 13 and there preferably soldered to this. Therefore, it is important to be able to easily remove the plastic layer 22 at the ends of the suction tube 2. At the other end 19 of the suction tube 2, this is connected to a drying cartridge 18 or to the condenser 16. Also, this connection can be made by soldering or welding, so that at the end 19, the throttle tube 2 must be freed from the plastic layer 22.

3 and 4 show preferred ways of connecting the suction pipe 4 with the throttle tube 2. According to FIG. 3, an adhesive tape 6 is used, preferably a plastic adhesive tape which extends lengthwise around the portions of the length L of the suction pipe 4 and the throttle tube 2 is glued.

As shown in FIG. 4, a clamp 8, for example made of plastic, can also be used in order to hold the throttle tube 2 in heat-conducting contact with the suction tube 4. For this purpose, it is also possible to use a plurality of clamps 8, which are clamped over the two tubes 2, 4 at intervals along the section at which the two tubes are intended to be in touching contact with one another.

With reference to FIG. 5, co-extrusion processes will now be described, by means of which a metal pipe, in particular copper pipe 12, can be coated with a sufficiently thin plastic layer 22. The copper tube 12 is initially wound as a continuous material on a roll 30. By driving the roller 30 in the direction of the arrows Q, the copper tube 12 is unrolled and fed to the extruder 32 via a guide roller 31. The extruder is also liquid plastic supplied via the worm drive 34. The copper tube 12 is pulled as a core or core through the extrusion die 33 and encased there from the outside with the plastic. In the region 35 behind the nozzle, the plastic hardens, and the coated throttle tube material 2 is wound on a further roller 36. As a result, an endless throttle tube 2 according to the invention is produced, which can be processed by cutting into finished throttle tubes. The plastic material contained in the screw 34 is, for example, PUR or PA (polyamide), wherein the liquid plastic may be mixed with a thermally conductive material in powder or granular form. For this purpose, preferably graphite comes into question. The invention provides an easily manufactured, corrosion-resistant throttle tube, which can be guided in heat-conducting contact with a suction tube or end portion of an evaporator tube, without violating standard specifications.

Claims

claims

1. Refrigeration appliance, in particular domestic refrigeration appliance, comprising a refrigerant circuit (10) comprising a throttle body in the form of a throttle tube (2), characterized in that the throttle tube (2) comprises a metal tube (12) which at least over a part of its length with a plastic layer (22) is sheathed.

2. Refrigerating appliance according to claim 1, characterized in that the metal tube (12) consists of copper or a copper alloy.

3. Refrigerating appliance according to claim 1 or 2, characterized in that the plastic layer (22) has a wall thickness between 20 and 500 microns.

4. Refrigerating appliance according to one of the preceding claims, characterized in that the plastic layer (22) comprises a thermoplastic or thermosetting plastic, in particular PUR, PP or PE.

5. Refrigerating appliance according to one of the preceding claims, characterized in that the plastic layer (22) is doped with a thermally conductive filler material.

6. Refrigerating appliance according to one of the preceding claims, characterized in that the throttle tube (2) at least over a portion (L) of its length in touching contact with a to a compressor (15) leading suction pipe (4).

7. Refrigerating appliance according to claim 6, characterized in that with the suction pipe (4) in contact portion of the throttle tube (2) parallel to a portion of the suction pipe (4) and is attached thereto.

8. Refrigerating appliance according to claim 6, characterized in that at least a portion of the throttle tube (2) is spirally placed in at least one turn around the suction pipe (4).

9. Refrigerating appliance according to one of claims 6 to 8, characterized in that the mutually contacting portions of the throttle tube (4) and the suction tube (2) in particular by means of adhesive tape (6) are fastened together.

10. Refrigerating appliance according to one of the preceding claims, characterized in that it is a refrigerator, a freezer or a fridge-freezer combination.

1 1. throttle tube (2) for a refrigeration device, wherein the throttle tube (2) comprises a metal tube (12), which is coated on its outside with a plastic layer (22).

12. Throttle tube (2) according to claim 11, characterized in that the metal tube (12) consists of copper or a copper alloy.

13. choke tube (2) according to claim 11 or 12, characterized in that the plastic layer (22) is between 20 and 500 microns thick.

14. Throttle pipe (2) according to any one of claims 1 1 to 13, characterized in that the plastic layer (22) comprises a thermoplastic or thermosetting plastic, in particular PUR, PP or PE.

15. Throttle pipe (2) according to one of claims 1 1 to 14, characterized in that the plastic layer (22) is doped with a thermally conductive filler material.

16. A method for producing a throttle tube (2) according to any one of claims 1 1 to 15 with the following steps: a) providing a metal tube (12), in particular a tube made of copper or a copper alloy; b) Coating the outside of the metal tube (12) by coextrusion with a plastic.