EP2567168A1

EP2567168A1 - Refrigerating device and evaporator for said device

Info

Publication number: EP2567168A1
Application number: EP11715491A
Authority: EP
Inventors: Stefan Holzer
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2010-05-04
Filing date: 2011-04-14
Publication date: 2013-03-13
Anticipated expiration: 2031-04-14
Also published as: CN102985778B; RU2012147338A; EP2567168B1; RU2529302C2; CN102985778A; DE102010028526A1; WO2011138145A1

Abstract

The invention relates to an evaporator for a refrigerating device, comprising a pipe (11) that conducts a coolant, at least one base (7) on which the pipe (11) is fixed, and a heat distributing plate (12) that lies between the pipe (11) and the base (7), said heat distributing plate supporting projections (18) that clamp the pipe (11).

Description

Refrigerating appliance and evaporator for it

The present invention relates to a refrigeration device, in particular a domestic refrigerator, and a usable in such a refrigerator evaporator. Such an evaporator conventionally comprises a pipe in which refrigerant circulates, a support plate to which the pipe is fixed and via the one

Heat exchange takes place between the tube and an interior of the refrigerator cooled by the evaporator, and a heat spreader layer disposed between the tube and the carrier plate, which provides efficient heat transfer between the carrier plate and the tube.

From DE 20 2005 000 909 U1 an evaporator of this type is known in which the carrier plate is a freezer compartment trough formed in an inner container of the refrigeration device, around which the tube is wound. As a heat spreader layer, metal plates can be placed between the tube and the freezer tray and to tube and

Freezer tray be attached with double-sided adhesive tape. Because the

Contact surface between the flat metal plate and the round tube is small, affects the double-sided adhesive tape at this point, the heat flow between the freezer well and tube considerably more than the large-scale tape layer between metal plate and freezer tray.

Object of the present invention is to provide an evaporator for a refrigerator, which at low cost the conventional evaporator in its thermal

Characteristics is at least equal.

The object is achieved by carrying in an evaporator for a refrigerator with a refrigerant pipe, at least one support plate to which the pipe is fixed, and arranged between the pipe and the carrier plate heat spreader plate, the heat spreader plate carries the tube clamping projections. This clamping allows on the one hand a quick mounting of the tube to the heat spreader plate and on the other hand a direct contact between the tube and the heat spreader plate. A heat transfer affecting adhesive layer between the pipe and

Heat spreader plate can therefore be omitted.

The tube-clamping projections are preferably formed integrally with the distributor plate to allow efficient heat exchange with the tube also over the

To allow projections themselves.

In order to enable a large-area heat exchange, the heat spreader plate preferably has a concave form-fitting to the pipe concavity. Preferably, the projections have mutually opposite concave flanks, so that the tube can be clamped between the opposite flanks of two projections.

In order to provide a large contact surface for efficient heat transfer, the projections may conveniently be formed as ribs extending along the tube.

When the evaporator is to be used for cooling a freezer compartment in a domestic refrigerator, the distributor plate should have a heat transfer coefficient of at least 0.4 Wm ^"2 K ^{" 1} .

According to a preferred embodiment, the distributor plate is formed from a plastic acted upon by a thermally conductive additive. While spread

Plastics such as PS or PE in pure form typically have values of

Thermal conductivity of 0.15 to 0.3 Wm ^"1 K ^{" 1} have, by suitable additives Wärmeleitfähigkeiten of about 1 Wm ^"1 K ^{" 1} without difficulty achievable.

Since this increased thermal conductivity is significantly smaller than that of a good heat-conducting metal, a greater thickness of the distributor plate is required to achieve a similar homogeneous heat distribution in the carrier plate as when using a metal distributor plate. However, the associated material costs are low compared to a metallic distributor plate, and the projections (and possibly the concavity) are much easier and cheaper to implement on a distribution plate made of plastic than on a distribution plate made of metal.

Preferably, the thermal conductivity of the acted upon by the additive

Plastic at least 1.5 Wm ^"1 K ^{" 1} , better still at least 2 Wm ^"1 K ^{" 1} .

Such thermal conductivity is easily accessible using graphite as a heat-conducting additive.

In practice, the graphite additive should preferably be at least 100 mg per cm ^{2 of} the area of the distribution plate, preferably at least 200 mg per cm ² of plate area.

Excessive graphite additives can increase the mechanical strength of the plastic

affect. Although resulting from a high graphite addition compliance of the plastic promotes close, large-scale contact between the pipe and

Distributor plate, but at the same time it affects - in particular when the projections are integrally formed with the distributor plate - the clamping force with which the tube is pressed against the distributor plate. It may therefore also be useful to use a metal powder as an additive that does not significantly affect the strength of the distributor plate. Although the metal powder can be abrasive on when forming the distributor plate used

Injection tools act, but can be counteracted by the simultaneous use of graphite by its lubricating effect.

The support plate may at the same time be a wall of an inner container, in particular of the freezer compartment, in a refrigerator according to the invention.

The use of the distributor plate is particularly advantageous when the carrier plate is the rear wall of the inner container, since a portion of the tube extending over the rear wall can not be fixed by wrapping around the inner container.

When a section of the pipe is helically around floor, ceiling and

Sidewalls of the inner container is wound, the distributor plate

expediently clamp at least one additional segment of the pipe, which is extends between adjacent segments of the helically wound section. With the at least one additional segment, it is possible to achieve a higher laying density of the pipe on one of the wound walls than on other walls in order to counteract, if necessary, temperature gradients in the storage compartment bounded by the inner container.

However, the invention is also applicable to an evaporator, the support plate is arranged freely in an interior of the refrigerator.

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

1 shows a schematic cross section through a household refrigerator according to the

Invention;

2 shows a section through a wall of the freezer compartment of the refrigerator of Figure 1 according to a first embodiment.

3 shows a section through a wall of the freezer compartment of the refrigerator of Figure 1 according to a second embodiment.

4 shows a section through a wall of the freezer compartment of the refrigerator of Figure 1 according to a third embodiment. Fig. 5 is a schematic perspective view of a freezer compartment inner container with an evaporator according to a fourth embodiment of the invention.

Fig. 1 shows a section through a combination household refrigeration appliance with a body 1, a normal refrigeration compartment 2, a freezer compartment 3 and doors 4, 5 for closing the two compartments 2, 3. The compartments 2, 3 are in a conventional manner by Plastic deep-drawn inner container delimited by a surrounding insulating material layer 6. The inner containers are each box-shaped with a door 4 or 5 open toward the front, a rear wall 7, ceiling floor and side walls 8, 9 and 10 respectively. The insulating material layer 6 facing outer sides of the walls 8, 9, 10 of the inner container of the freezer compartment 3 are made with a graphite foil or

glued graphite-filled plastic, which is not visible in Fig. 1 due to their small size. The foil may be glued individually piece by piece to each wall 8, 9, 10, or it may be wound in one piece around all four walls 8, 9, 10. A

Heat distribution plate 12 is fixed in two compartments 2, 3 on one of the insulation material layer 6 facing outside of the rear wall 7 by means of large-surface-mounted double-sided adhesive tape or other suitable adhesive. In the case of the freezer compartment 3, the refrigerant tube 1 1 is connected in series with a tube 20 which is in close contact with the film helically over the walls 8, 9, 10 of the Inner container extends.

Fig. 2 shows a section through the rear wall 7, the heat spreader plate 12 and attached to her tube 1 1 of the normal refrigeration compartment 2 or the freezer compartment 3 in section along a vertical plane. The tube 1 1 extends on the distributor plate 12 in a plurality of meanders with horizontally oriented rectilinear segments 13 and the segments 13 in series semicircular arches 14. The segments 13 are attached to the distributor plate 12 by means of hooks 15 which are integral with the distributor plate 12th are injection molded. The hooks 15 are circular arc-shaped with a radius of curvature which is slightly smaller than the radius of the tube 1 1 in the relaxed state, so that when the tube 1 1 is mounted as shown, the hooks 15 are under tension, close to the

Cling segments 13 and press them against the distributor plate 12.

In the upper part of Fig. 2, two hooks 15 are shown, on which no segment 13 of the tube 1 1 is mounted. It can be seen here a channel 16 which is formed in the surface of the distributor plate 12 following the intended course of the tube 1 1. The radius of curvature of the cross-sectionally circular channel 16 corresponds to that of the tube segments 13, so that when the tube 1 1 is mounted, a tube segment 13 held by the hooks 15 contacts the distributor plate 12 over the entire surface of the channel 16. This and the lack of a poorly heat-conductive adhesive layer between the tube 1 1 and the distributor plate 12 ensures efficient heat exchange between the tube 1 1 and the distributor plate 12th Particularly easy to shape is the distributor plate 12, when the hook 15 respectively

Openings 17 of the plate are opposite, as shown in Fig. 3. Thus, to form the distributor plate 12 including the hooks 15 is a simple mold with two mutually movable parts, one of which the inner container wall 7 facing side of the distributor plate 12 and, with the aid of through the openings 17 cross-projections, the inner sides of the hook 15th and the other forms the insulating material layer 6 facing side of the distributor plate 12 and the outer sides of the hooks 15.

FIG. 4 shows, in a view analogous to FIGS. 2 and 3, a preferred development of the invention. The hooks 15 are here replaced by protruding from the distributor plate 12, in pairs opposite ribs 18. The ribs 18 extend in the horizontal direction in each case over the entire length of a straight segment 13 of the tube 1 first Concave flanks 19 on the mutually facing sides of the ribs 18 nestle closely to the tube 1 1 and allow an efficient

Heat exchange to more than half of the circumference of the tube 1 1.

In order to uniformly cool the rear wall 7 over its entire area covered by the distributor plate 12, the distributor plate 12 must conduct heat better than in the case of the heat exchanger

Refrigeration equipment hitherto widespread pure plastics do so. In order to ensure a sufficient thermal conductivity of the distributor plate 12, it is provided according to the invention to manufacture the plate 12 according to any of the embodiments described above from a plastic acted upon by a good heat-conductive additive, in particular polystyrene with added graphite. By adding graphite to the polystyrene, a thermal conductivity of 2 Wm ^"1 K ^{" 1} can be achieved without unduly impairing the strength of the material. With a thickness of the plate of 1, 5 mm so a heat transfer coefficient of 0.467 Wm ^"2 K ^{" 1 is} reached. The graphite additive for this purpose is preferably at least 100 mg per cm ² area of the distributor plate 12, better still at least 200 mg graphite / cm ² . It is also conceivable, the required thermal conductivity by an addition of

Metal powder, for example, aluminum powder to realize the plastic of the distributor plate 12. By using metal powder instead of graphite one can

Reduction of the strength of the finished distributor plate 12 avoided or at least be reduced. However, a problem is that the metal powder is abrasive to the molds used to make the distributor plate 12. It is also conceivable to mix metal powder and graphite additives. By keeping the graphite content lower than with graphite only material of equal thermal conductivity, the loss of strength of the material can be limited. At the same time, the lubricating effect of the graphite reduces the abrasive effect of the metal powder on the molds.

Fig. 5 shows in a perspective view obliquely from below a freezer compartment inner container according to a further development of the present invention. Ceiling, bottom and side walls 8, 9, 10 of the inner container are coated with a graphite-containing foil, which like the distribution plate 12 described above as a

Heat spreader layer between the walls 8, 9, 10 of the inner container and the helically wound around these walls 8, 9, 10 tube 20 acts. The graphite-containing film may consist of substantially pure graphite. To one

Heat transfer coefficient of 0.47 W / m ² K to achieve a cost, 100μηη thick film is sufficient. Instead of the pure graphite foil, it is also possible to use a foil in which, for better handleability, a graphite layer between two

Plastic film is embedded, or a one-layer made of a plastic material with a high added Graphitanteil and accordingly soft film.

On the rear wall 7 of the inner container, the tube 1 1 with the help of the already

described distributor plate 12 is fixed. Thus, the freezer can be cooled from five sides at the same time, only on its open front can still penetrate heat. In order to compensate for the incidence of heat at the open front and to obtain as homogeneous a temperature distribution in the freezer compartment, it is desirable to increase the density with which the tubes are laid in a front region of at least the bottom wall 9. However, such increased laying density on a single wall is not feasible with the tube 20 wound helically around the walls 8, 9, 10. In order nevertheless to be able to increase the laying density in the front region of the bottom wall 9, a second plate 21 made of graphite-containing plastic is attached here. It may be glued to the graphite-containing foil, or the foil is recessed in the area occupied by the plate 21. A segment 22 of the tube 20 wound around the walls 8, 9, 10 extends over the distributor plate 21 in the longitudinal direction. On both sides of this tube segment 22 pairs of ribs 18 are formed, which clamp between them to the tube segment 22 parallel tube segments 23, 24. These tube segments 23, 24 are connected to each other and to one end of the helically wound around the walls of the tube 20 via arches 25, 26. A along an edge 27 between the bottom and side walls 9, 10 extending

Pipe 28 provides a connection to the extending over the rear wall 7 pipe 1 1 ago.

Claims

1. evaporator for a refrigeration device with a refrigerant-carrying tube (1 1, 23, 24), at least one support plate (7, 9), to which the tube (1 1, 23, 24) is fixed, and one between the tube ( 1, 23, 24) and the support plate (7, 9) arranged heat distribution plate (12, 21), characterized in that the heat distribution plate (12, 21) the tube (1 1, 23, 24) clamping projections (15, 18 ) wearing.

2. An evaporator according to claim 1, characterized in that the projections (15; 18) are formed integrally with the distributor plate (12; 21).

3. evaporator according to claim 1 or 2, characterized in that the

Heat distribution plate (12, 21) has a form-fitting manner to the tube (1 1; 23, 24) conforming concave (16).

4. Vaporizer according to one of the preceding claims, characterized in that the projections (18) each other in pairs opposite concave flanks (19).

5. Evaporator according to one of the preceding claims, characterized in that the projections (18) are formed as along the tube (1 1; 23, 24) extending ribs.

6. evaporator according to one of the preceding claims, characterized in that the distributor plate (12; 21) has a heat transfer coefficient of at least 0.4 Wm- 2K-1.

7. Evaporator according to one of the preceding claims, characterized in that the distributor plate (12; 21) is formed from a plastic acted upon by a heat-conducting additive.

8. evaporator according to claim 7, characterized in that the thermal conductivity of the acted upon by the additive plastic at least 1, 5 Wm-1 K-1.

9. evaporator according to claim 7 or 8, characterized in that the additive

Includes graphite.

10. An evaporator according to claim 9, characterized in that the graphite content of the distributor plate (12; 21) is at least 100 mg / cm ^{2 of} the plate surface, preferably at least 200 mg / cm ^{2 of} the plate surface.

1 1. An evaporator according to any one of claims 6 to 9, characterized in that the additive comprises metal powder.

12. Refrigerating appliance, in particular household refrigerating appliance, with an evaporator according to one of the preceding claims, characterized in that the carrier plate (7, 9) is a wall of an inner container of the refrigerating appliance.

13. Refrigerating appliance according to claim 12, characterized in that the wall (7) a

Rear wall of the inner container is.

14. Refrigerating appliance according to claim 12, characterized in that a portion (20) of the tube is helically wound around bottom ceiling and side walls (8, 9, 10) of the inner container and the distributor plate (21) at least one segment (23, 24 ) of the tube extending between adjacent segments (22) of the helically wound section (20).

15. Refrigerating appliance with an evaporator according to one of claims 1 to 1 1, characterized

characterized in that the carrier plate is arranged freely in an interior of the refrigeration device.