WO2012010422A2

WO2012010422A2 - Refrigeration device with a defrosting device

Info

Publication number: WO2012010422A2
Application number: PCT/EP2011/061454
Authority: WO
Inventors: Markus Hopf
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2010-07-23
Filing date: 2011-07-07
Publication date: 2012-01-26
Also published as: WO2012010422A3; DE102010038384A1

Abstract

The invention relates to a refrigeration device, in particular a domestic refrigeration device, comprising a block-shaped evaporator (5) and a heating device comprising a plate (9) extending adjacent to one side of the block-shaped compressor (5). Said refrigeration device is characterised in that the heating device comprises fins (10) protruding from the plate (9) which engage in the block-shaped evaporator (5).

Description

Refrigerating appliance with defrosting device

The present invention relates to a refrigeration device, in particular a household refrigerating appliance, with a heating device for the automatic defrosting of an evaporator. On the evaporator of a refrigerator forms an ice layer during operation. This hinders the heat exchange between the evaporator and a storage room of the freezer, on the one hand, by forming an insulating layer between them, on the other hand, by obstructing the air circulation at the evaporator. It is therefore necessary to defrost the ice layer from time to time. To automate this process, many refrigerators are equipped with a defrost heater.

From DE 10 2008 033 798 A1 a refrigerator is known in which a foil-shaped defrosting device is glued under a condensation drainage channel. The condensation drainage channel extends under the evaporator so that warm air rising from it reaches the evaporator and melts the ice layer adhering to it.

Since the evaporator is heated substantially only by rising air, a long time is required to transport the amount of heat required to remove the ice layer to the evaporator. Although the transport speed can be increased by increasing the performance of the defrost heater or by increasing the temperature difference between the defrost spout and the evaporator during defrosting, all the heat energy dissipated by the heater and not used to defrost the ice must be exhausted after defrosting be removed again the device, which significantly affects its energy efficiency. In addition, the ice sheet also impedes the spread of the hot air rising from the condensation drainage channel in the evaporator, so that it tends to defrost along a front which slowly spreads from bottom to top through the evaporator. As a result, at a time when the most remote from the condensation drainage trough parts of the evaporator, located closer to the condensation drainage trough parts of the evaporator are already free of ice and heat up undesirably strong. Object of the present invention is to provide a refrigeration device with a defrost heater, which allows a quick defrosting, without affecting the energy efficiency of the refrigerator unnecessarily.

The problem is solved by a refrigeration device, in particular a

Household refrigerating appliance, comprising a block-shaped evaporator and a plate extending adjacent to one side of the block-shaped evaporator

Heater has the heater protruding from the plate finger, which engage in the block-shaped evaporator. These - preferably from a gut

Thermally conductive metal existing - fingers allow rapid feeding of the heat given off by the heater in the evaporator, even if the

Temperature difference between heater and evaporator is low. Heat losses, which can occur conventionally when heated air at the heater does not reach the evaporator, can be avoided. The fingers can be easily and inexpensively obtained by cutting free from a base plate of the heater.

For heating the - preferably metallic - base plate may suitably serve a glued foil heating.

Conductor tracks of the film heater can be conveniently made by screen printing. On the one hand, this makes it possible to adapt the course of the strip conductors to the position of the cut-out fingers in the manufacture of the film heater, and on the other hand, the heating power density of the film heater can also be changed by varying the cross-section of the strip conductors in order to release heating power at the points in this way where it is most needed or from which it can be transported to the evaporator most quickly.

To get a fast, efficient heat transport into the evaporator

ensure that the film heater should expediently extend to the fingers. Conveniently, then the power density of the film heating on the fingers can be higher than other areas of the base plate, which are less closely thermally coupled to the evaporator. The fingers preferably have bifurcated tips to each a tube of the

To surround vaporizer. This allows both a safe and accurate placement of the heater and the evaporator relative to each other as well as efficient heat transfer from the fingers to the pipe. When the evaporator is a finned evaporator, the fingers are preferably aligned parallel to the fins of the evaporator to allow air to flow through the finned evaporator

Evaporator through as little as possible to hinder.

A flat contact at least one of the fingers on a blade of the evaporator additionally promotes heat transfer to the evaporator.

The close thermal contact between the heating device and the evaporator makes it expedient to provide a temperature sensor on the heating device. Such a temperature sensor can be attached to the heater with significantly less effort than the evaporator, since the heater has to be wired anyway to be energized, whereas the evaporator requires no electrical wiring for its operation.

In particular, when the temperature sensor is attached to one of the fingers, it enables a precise judgment of the temperature of the evaporator and, based thereon, a safe decision as to whether defrosting of the evaporator is necessary or not.

The attachment of the temperature sensor is particularly simple if it is arranged with a conductor of the film heating on a same film and thus can be glued together in one operation together with the film heater to the base plate.

In order to distribute the heat output as needed, the heater can be divided into several separately acted upon by electricity heating circuits.

Preferably, in one of the heating circuits a trough heating is assigned, via the

Meltwater is removed from the evaporator. In order to control the heat output of each circuit as needed, can

expediently be assigned to each heating circuit means for temperature detection. These means may comprise, for example, a temperature sensor adjacent to the heating circuit; But it can also be a trace of the heating circuit itself as

Temperature sensor serve by their temperature-dependent resistance is evaluated.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. 1 shows a schematic section through a refrigeration device with an evaporator and a heating device for defrosting the

Evaporator according to the present invention;

FIG. 2 is a plan view of a base plate of the heater according to a first embodiment; FIG.

Fig. 3 is a plan view of a first embodiment of a film heater for attachment to the base plate of Fig. 2; 4 shows a schematic cross section through the film heater of FIG.

3;

5 shows a second embodiment of the film heater in plan view. 6 shows a third embodiment of the film heater;

7 shows a fourth embodiment of the film heater;

Fig. 8 is a perspective view of the base plate; and

Fig. 9 is a section in the width direction through the evaporator and the

Heating device. Fig. 1 shows in a schematic section the upper part of an inventive

Household refrigerating appliance. A heat-insulating body 1 surrounds an interior, which is divided by a partition 4 into a storage chamber 2 for refrigerated goods and a

Evaporator chamber 3. The evaporator chamber includes a finned evaporator 5 and a fan 6, the air exchange between the storage chamber 2 and the evaporator chamber 3 via openings 7, 8 at the front and rear edge of the

Partition 4 drives. A base plate 9 of a defrost heater covers a large part of the partition wall 4 between the openings 7, 8, and from the base plate notched, forked fingers 10 carry the fin evaporator 5 by embracing a meandering refrigerant pipe 1 1 of the evaporator 5. A bonded to the base plate 9 film heater is not visible in Fig. 1 for reasons of scale. At the rear edge of the back wall of the body 1 down sloping base plate 9 is a transverse to the sectional plane of FIG. 1 extending collecting channel 12 is formed in the water that drips from the evaporator 5 defrosts, collects. From the collecting channel 12, a channel 13 extends through the rear wall of the body 1 to an evaporation tray, not shown.

Fig. 2 shows a plan view of the base plate 9 in a partially finished state. In the base plate 9 made of aluminum sheet approximately M-shaped slots 14 are punched in several rows and columns in plan view. The number of rows and columns of the slots 14 may vary depending on the design of the finned evaporator 5. The slots 14 limit the still to be deflected from the plane of the base plate 9 vertical fingers 10. A free of slots 14 part 15 of the base plate 9 is provided to form the collecting channel 12 therefrom. A dotted line indicates the edge of a foil heater 16, which is intended to be glued to the base plate 9.

Fig. 3 shows a plan view of a piece of the film heater 16 according to a first embodiment, and Fig. 4 shows the film heater 16 in section along the line IV-IV of Fig. 3. On a carrier film 17 of the film heater 16 is a conductor 18 in

Screen printing applied. From the conductor track 18 free areas of the carrier film 17 are welded to a cover sheet 19 to enclose the conductor 18 protected from moisture. In the carrier film 17 and the cover sheet 19 C-shaped slots 20 are punched, which, when the film heater 16 is glued to the base plate 9, with their dashed lines in Fig. 3 shown slots 14 overlap partially. Of the Slots 20 bound tongues 21 of the film heater 16 are first fixed by a the slide 20 bridging release liner 22.

The trace 18 is shown in Fig. 3 in part by an exact outline, in part only by an approximate course suggestive line. It extends along the columns of fingers 10 and extends to each tongue 21. Incisions 23 force the entire current flowing in the conductor 18 over the tongues 21st On the tongues 21, the width of the conductor track 18 in each case reaches its smallest value, and accordingly the heating power density of the conductor track 18 is highest here. The film heater 16 with the structure shown in Fig. 4 is glued before the deflection of the fingers 10 on the base plate 9. A self-adhesive layer 24 on the underside of the carrier film 17 is recessed in a region 25 adjoining the slot 20, in order to prevent this region of the film heater, which can not follow the deflection of the fingers 10, from sticking to the fingers. After adhering the film heater 16, the release liner 22 is removed so that it does not hinder the deflection of the fingers 10.

FIG. 5 shows an embodiment of the film heater 16 modified in three independently realizable aspects. According to the first aspect, the C-shaped slots 20 are widened in their central region 26 such that the film heater uncovers the tips of the fingers 10 after removal of the release liner 22 leaves. This facilitates the sticking of the foil heater to the base plate 9 placing a

Tool for deflecting the fingers 10.

According to the second aspect, the film heater is divided into a plurality of heating circuits with conductor tracks 18a, 18b, 18c, which can be supplied with current independently of each other. In each case, the conductor tracks heat areas of the base plate 9 which are located one behind the other in relation to the direction of flow of the air in the evaporator chamber 3. This makes it possible, for example, for the conductor track 18a, which heats the area of the evaporator 5 which is located furthest upstream and therefore heavily loaded with ice, to be longer or to power with higher power than the tracks 18b, 18c. In order to monitor the heat output of the individual heating circuits, adjacent to each of the conductor tracks 18a, 18b, 18c, a temperature sensor 24 may be welded between the films 17, 19. But it is also possible, the temperature of the individual tracks from afar by a control circuit Based on the temperature-dependent variable ohmic resistance of

To record traces.

The third aspect concerns the width of the tracks 18a, 18b, 18c. It is constant here and so small that several meanders can be placed side by side on each tongue 21 place. By the meanders on the tongues 21 are denser than on the undeflected areas of the base plate 9, a high heating power density is achieved at the fingers 10.

Fig. 6 shows a fourth, with the Abwandlungsmöglichkeiten according to the first to third aspect of any combinable modification of the film heater 16. Here is in one of

Tongues 21 of the recess 23 widened to make room for two conductors 27 which connect a temperature sensor 28 placed on the tongue 21 at the end of the incision 23 with contact pads 29 at one edge of the foil heater 16. These contact fields 29 may be arranged directly adjacent to contact fields 30 for the power supply of the conductor track 18, so that the wiring of the sensor 28 with a (not shown) control circuit of the refrigerator, which controls in particular the operation of the defrost heater based on the temperature detected by the temperature sensor 28 and for this purpose anyway connected to the contact fields 30, with minimal effort is possible.

In the embodiment of FIG. 7 is a tongue 21 of the film heater 16 of the

Conductor track 18 is kept free, in order to allow with the temperature sensor 28 placed there a measurement of the evaporator temperature that is as little as possible falsified during defrosting by the heating effect of the conductor track 18.

8 shows the finished heating device with the fingers 10 deflected vertically out of the base plate 9 and the tongues 21 of the foil heater 16 extending onto the fingers 10. While the fingers 10 and the tongues 21 in the illustrations of FIGS. 2 to 8 are all aligned identically Also, a partially mirror-image arrangement of fingers 10 or tongues 21 is conceivable.

FIG. 9 shows a schematic section through the finned evaporator 5 and the heating device with such partially mirror-inverted fingers 10. These Arrangement allows the fingers 10 elastically and over a large area against the blades 31 of the evaporator 5 and thus ensure close thermal contact between the film heater 16 and the evaporator 5.

As can also be seen clearly in FIG. 9, the fingers 10 support this

Refrigerant pipe 1 1 not in the bottom, the base plate 9 next adjacent level 1 1 a, but in a next higher level 1 1 b, so as to increase the contact area between the fingers 10 and the fins 31 and the heat transfer to

intensify.

Claims

Refrigerating appliance, in particular household refrigerating appliance, with a block-shaped evaporator (5) and a heating device having a plate (9) extending adjacent to one side of the block-shaped evaporator (5), characterized in that the heating device projects fingers (10) projecting from the plate (9) ), which engage in the block-shaped evaporator (5).

Refrigerating appliance according to claim 1, characterized in that the fingers (10) are cut free from the plate (9).

Refrigerating appliance according to claim 1 or 2, characterized in that the

Heater has a on the plate (9) glued foil heater (17, 18, 19).

Refrigerating appliance according to claim 3, characterized in that the foil heating (17, 18, 19) has screen printed printed conductors (18).

Refrigerating appliance according to claim 3 or 4, characterized in that the foil heater (17, 18, 19) extends to the fingers (10).

Refrigerating appliance according to one of the preceding claims, characterized in that the fingers (10) have bifurcated tips which surround a tube (1 1) of the evaporator (5).

Refrigerating appliance according to one of the preceding claims, characterized in that the evaporator (5) is a finned evaporator and the fingers (10) are aligned parallel to the fins (31) of the evaporator (5).

8. Refrigerating appliance according to claim 7, characterized in that at least one of the fingers (10) on a lamella (31) of the evaporator (5) rests flat.

9. Refrigerating appliance according to one of the preceding claims, characterized in that the heating device (17, 18, 19) has a temperature sensor (24).

10. Refrigerating appliance according to claim 9, characterized in that the temperature sensor (24) on one of the fingers (10) is mounted.

1 1. Refrigerating appliance according to claim 9 or 10, as far as dependent on claim 3, characterized in that the temperature sensor (24) and a conductor track (18) of the film heater (17, 18, 19) arranged on a same film (17, 19) are.

12. Refrigerating appliance according to one of the preceding claims, characterized in that the heating device (17, 18, 19) is divided into a plurality of separately energized heating circuits (18a, 18b, 18c).

13. Refrigerating appliance according to claim 12, characterized in that each heating circuit (18a, 18b, 18c) are associated with means for temperature detection.

14. Refrigerating appliance according to claim 12 or 13, characterized in that one of the heating circuits (18a, 18b, 18c) is associated with a gutter for melt water, via which the melt water from the evaporator (5) is removed.