REFRIGERATION APPLIANCE HAVING A SIPHON IN THE CONDENSATE DRAIN

Abstract

A refrigeration appliance, particularly a domestic refrigeration appliance, has an inner chamber surrounded by a thermal barrier coating, an evaporator which cools the inner chamber, and a condensate drain which leads into the open from the evaporator through the thermal barrier coating. The condensate drain includes a siphon, which is arranged on the inner side of the thermal barrier coating and which is heatable by a defrost heater.

Description

The present invention relates to a refrigeration appliance, in particular a domestic refrigeration appliance, comprising an inner compartment surrounded by a thermal insulation layer, an evaporator which cools the inner compartment, and a condensate drain which leads into the open from the evaporator through said thermal insulation layer.

If a condensate drain of this kind can be passed through freely during operation of the refrigeration appliance, then there is a constant air exchange with the surroundings via the condensate drain, and heat and moisture find their way into the inner compartment via the condensate drain in an undesirable manner. In order to prevent this, it is known from DE 10 2008 040 430 A1 for example to provide a siphon in the condensate drain which, by containing liquid water at all times, only allows air to pass between the inner compartment and the surroundings when a sufficiently large pressure difference is present between the interior and exterior.

Such a siphon may, at least in a refrigeration appliance, the inner compartment of which reaches temperatures below 0 degrees Celsius, only be arranged outside the thermal insulation layer, since a freezing of water contained in the siphon would cause it to clog and render it useless. Accommodating the siphon in the machine room is difficult, since it must neither block the cooling of the components present there nor heat up near said components to the extent that it dries up in a short space of time and the air tightness of the siphon between two defrost cycles is not ensured. Mounting the siphon onto a rear wall of the appliance is also problematic, since this requires either a reduction in the size of the rear wall evaporator conventionally provided there, or the bringing forward of the thermal insulation layer of the rear wall and thus entails a considerable loss of usable volume.

The object of the invention is to specify a refrigeration appliance, which enables a simple and space-saving installation of a siphon in the condensate drain.

The object is achieved for a refrigeration appliance, in particular a domestic refrigeration appliance comprising an inner compartment surrounded by a thermal insulation layer, an evaporator which cools the inner compartment and a condensate drain which leads into the open from the evaporator through said thermal insulation layer and has a siphon, by the siphon being arranged on the inner side of the thermal insulation layer and being heatable by a defrost heater. In the inner compartment, the siphon should be accommodated relatively easily, without an associated displacement of the thermal insulation layer and thus a noticeable loss of usable volume. The risk of the condensate drain becoming air-permeable as a result of premature evaporation of the water in the siphon is eliminated by the low temperature at which the siphon is kept. By guiding the condensate drain along a short, preferably straight path through the thermal insulation layer, the weakening of the insulating effect of the thermal insulation layer by the condensate drain is limited to a minimum. As long as the water in the condensate drain is frozen, there forms an immovable obstruction, which also prevents the occurrence of bubbling noises, which occur in a siphon filled with liquid water when for example warm air, which has found its way into the inner compartment of the refrigeration appliance when the door is opened, cools down therein and surrounding air is sucked in via the siphon as a result.

The defrost heater of the siphon should be coupled to a defrost heater for the evaporator from a functional perspective, in order to ensure that the siphon is permeable or becomes permeable at the right time, when the evaporator is defrosted and condensate is to be drained therefrom via the siphon.

It is conceivable to operate the heaters of the siphon and the evaporator in a staggered manner, in particular the heater of the siphon can be brought into operation shortly before the start of a defrost process, in order to ensure that the contents of the siphon becomes liquid at the right time and thus the siphon is permeable when the condensate begins to flow from the evaporator.

Since, in practice, the evaporator also requires a particular operating time for its defrost heater until the condensate begins to flow, both heaters may also be controlled via a common switch and thus operated simultaneously; according to a preferred embodiment a common defrost heater may be provided for the evaporator and for the siphon.

If the inner compartment is divided into a storage chamber and an evaporator chamber, the siphon is preferably arranged on the base of a depression in the evaporator chamber.

The defrost heater may extend over the depression, in order to heat it over a wide area, in particular by radiation.

The defrost heater may extend between the evaporator and the depression, in order to emit heat downward to the depression and upward to the evaporator simultaneously.

The defrost heater may in particular be in the shape of a plate or rod.

In order for the defrost heater to be able to defrost the siphon in a reasonably short time by radiation, its operating temperature must lie considerably above 0° C.; it may then also heat the evaporator by radiation.

The base of the depression should be sloping with respect to the siphon, on the one hand in order to collect the condensate at the siphon, on the other hand in order to be able to keep a high-lying part of the base free from water or ice, so that during a defrosting it can store radiation directly from the defrost heater lying above and transfer the radiant heat to the ice in the siphon.

To make the heat conducting process effective, the base of the depression may be provided with an infrared-absorbing surface layer.

In order to ensure a rapid transmission of the stored heat to the ice, the base of the depression may further be at least partially metallic.

Expediently, the siphon is formed by a connector protruding above the base of the depression and a cup put over the connector.

A lower edge of the cup should lie at most 2 mm below the upper edge of the connector, in order to limit the quantity of water which has to be defrosted in order to make the siphon permeable.

In order to accelerate this defrosting, a surface of the siphon facing toward the defrost heater, in particular a top side of the cup, may be provided with an infrared-absorbing surface layer.

Further features and advantages of the invention will emerge from the description of exemplary embodiments provided below, with reference to the attached figures, in which:

FIG. 1 shows a schematic cross-section through a domestic refrigeration appliance according to the invention;

FIG. 2 shows an enlarged extract from FIG. 1 in accordance with a first embodiment;

FIG. 3 shows a similar cross-section to FIG. 2 in accordance with a second embodiment; and

FIG. 4 shows a partial section through a refrigeration appliance in accordance with a third embodiment of the invention.

FIG. 1 shows a schematic cross-section through a no-frost domestic refrigeration appliance with a carcass 1 and a door 2, which are in each case foamed with a thermal insulation layer 3 and surround an inner compartment 4. The inner compartment 4 is divided by a dividing wall 5 into a storage chamber 6 accessible via the door 2 and an evaporator chamber 7, which extends with an upright orientation between the dividing wall 5 and a rear wall 8 of the carcass 1. The evaporator chamber 7 is filled to a great extent by an evaporator 9, typically a fin evaporator. A fan 10 is arranged in an opening of the dividing wall 5, in order to drive air circulation between the storage chamber 6 and the evaporator chamber 7 when the evaporator 9 is operating.

A horizontal or slightly forwardly inclined wall 11 of the carcass 1 separates the evaporator chamber 7 from a machine room 12, which lies outside the thermal insulation layer 3 and contains a compressor 13 etc.

An inner container deep-drawn from plastic separates the inner compartment 4 from the thermal insulation layer 3 in the conventional manner. A depression 14 is formed on the base of the evaporator chamber 7 in the inner container, which extends over the entire width of the evaporator chamber 7. A siphon 15 at the deepest point of the depression 14 forms the starting point of a condensate drain 16, which extends vertically through the wall 11 to an evaporation pan 17 heated by the compressor 13 in the machine room 12.

FIG. 2 shows the siphon 15 and its surroundings in an enlarged cross-section in accordance with a first embodiment of the invention. The siphon 15 comprises a cylindrical connector 18, which extends upward from the base of the depression 14, as well as a pan or a cup 19, which is put over the free end of the connector 18 upside down. In order to keep a base 20 of the cup 19 at a distance from the upper edge 21 of the connector 18, the surrounding wall 22 of the cup 19 may be provided with small individual feet 23, which are supported around the connector 18 on the base of the depression 14, here in a trench 24 surrounding the connector 18.

An electrical resistor heater 25 is attached to an outer side of the trench 24 facing toward the thermal insulation layer 3 and can be operated together with a resistance heater 26 attached to the fin evaporator 9, in order to also defrost the water in the trench 24 during a defrosting of the evaporator 9 at the right time in each case, so that a free draining of the defrost water from the evaporator 9 via the condensate drain 16 to the evaporation pan 17 is ensured. Following the conclusion of the defrost process, the trench 24 remains filled with water up to the upper edge 21 of the connector 18, so that as soon as the evaporator 9 cools again, the water in the trench 24 freezes and seals the siphon 15 tightly.

FIG. 3 shows a schematic cross-section through the siphon 15 in accordance with a preferred second embodiment of the invention. Here, a plate-shaped resistance heater 27 is arranged with a horizontal orientation over the depression 14 and below the fin evaporator 9. In its place, a rod-shaped heater could also be provided and in particular could be oriented in a straight line perpendicular to the cross-section plane or could run in a horizontal plane in a serpentine manner. A second heater could be arranged immediately on the fin evaporator 9 as in the heater 26 of FIG. 2 and be operated together with the resistance heater 27 in order to heat the evaporator 9, when the resistance heater 27 simultaneously heats the water in the siphon 15. In the embodiment shown in FIG. 3, infrared radiation emitted by the resistance heater 27 heats both the fin evaporator 9 and also the siphon 15.

Infrared radiation emitted downward by the heater 27 is intercepted on the one hand by the cup 19 and on the other by the base of the depression 14. The cup 19 emits the heat which it has intercepted to the body of ice 28 via the lower edge of the wall 22 submerged in the body of ice 28 surrounding the connector 18. So that defrost water flowing in from the evaporator 9 is able to drain, the body of ice 28 must not be completely defrosted. Rather, it is sufficient if the ice has been liquefied continuously from the outside to the inside at one point along the circumference of the wall 22. The lower the vertical overlap d between the wall 22 and the connector 18, the smaller the quantity of ice immediately at the surface of the wall 2, to which the cup 19 emits its heat and which has to be liquefied in order to make the siphon 15 permeable.

In order to ensure a rapid draining of the defrost water, it is useful, however, if the body of ice 28 is completely defrosted straight away. The walls 29 of the depression 14 steeply sloping toward the siphon 15 and the low height of the connector 18 ensure that at the end of each defrost process only a small part of the walls 29 around the connector 18 is covered by water; the majority of the walls 29 which lies higher than the upper edge 21 of the connector 18 therefore remains ice-free during the cooling operation and quickly heats up during the following defrost process due to the radiation of the heater 27. In order to rapidly divert this heat to the body of ice 28, the walls 29 may be coated with a thin metal sheet 30 or a metal film; in order to render the absorption of the infrared radiation effective, the metal sheet 30 and the cup 19 may in each case be provided with yet another infrared-absorbing coating 31.

FIG. 4 shows as a third embodiment of the invention a schematic cross-section through a siphon 15 and the surroundings thereof in a refrigeration appliance with an evaporator chamber 7 arranged horizontally below a cover 32 of the carcass. Here, the heater 27 extends below a width side of the fin evaporator 9 and can heat it both by radiation and also by direct contact. Between a front region of the heater 27 and the wall 5 separating the evaporator chamber 7 from the storage chamber 6, an infrared-reflecting film 33 is arranged in order to minimize the heat emission to the wall 5 which lies below and separates the evaporator chamber 7 from the storage chamber 6.

Film 33 and wall 5 are steeply inclined with respect to the rear wall 8, in order to guide defrost water draining from the evaporator 9 to the depression 14, which is arranged here in a rear part of the wall 5. A rear region 34 of the heater 27 protruding out beyond the heater 27 emits heat radiation downward, in order to heat the depression 14 and the siphon 15—here constructed in the exact same manner as in the embodiment in FIG. 2.

REFERENCE CHARACTERS

• 1 Carcass
• 2 Door
• 3 Thermal insulation layer
• 4 Inner compartment
• 5 Dividing wall
• 6 Storage chamber
• 7 Evaporator chamber
• 8 Rear wall
• 9 Evaporator
• 10 Fan
• 11 Wall
• 12 Machine room
• 13 Compressor
• 14 Depression
• 15 Siphon
• 16 Condensate drain
• 17 Evaporation pan
• 18 Connector
• 19 Cup
• 20 Base
• 21 Upper edge
• 22 Wall
• 23 Small foot
• 24 Trench
• 25 Resistance heater
• 26 Resistance heater
• 27 Resistance heater
• 28 Body of ice
• 29 Wall
• 30 Metal sheet
• 31 Coating
• 32 Cover
• 33 Film
• 34 Rear region

Claims

1-14. (canceled)

15. A refrigeration appliance, comprising:

a thermal insulation layer surrounding an inner compartment;

an evaporator configured to cool said inner compartment;

a condensate drain leading from said evaporator through said thermal insulation layer and into the open, said condensate drain including a siphon disposed on an inner side of said thermal insulation layer; and

a defrost heater configured for heating said siphon.

16. The refrigeration appliance according to claim 15, wherein said defrost heater of said siphon is functionally coupled to a further defrost heater for said evaporator.

17. The refrigeration appliance according to claim 15, wherein said defrost heater is a common defrost heater for said evaporator and for said siphon.

18. The refrigeration appliance according to claim 15, wherein said inner compartment is divided into a storage chamber and an evaporator chamber, said evaporator chamber is formed with a depression, and said siphon is arranged on a base of said depression formed in said evaporator chamber.

19. The refrigeration appliance according to claim 18, wherein said defrost heater extends over said depression.

20. The refrigeration appliance according to claim 18, wherein said defrost heater extends between said evaporator and said depression.

21. The refrigeration appliance according to claim 18, wherein said defrost heater is plate-shaped or rod-shaped.

22. The refrigeration appliance according to claim 18, wherein said evaporator chamber is arranged upright on a rear side of said inner compartment and said defrost heater is a radiation heater.

23. The refrigeration appliance according to claim 18, wherein the base of said depression is sloped towards said siphon.

24. The refrigeration appliance according to claim 18, comprising an IR-absorbing surface layer on the base of said depression.

25. The refrigeration appliance according to claim 18, wherein the base of said depression is at least partially metallic.

26. The refrigeration appliance according to claim 18, wherein said siphon comprises a connector protruding above the base of said depression and a cup disposed on said connector.

27. The refrigeration appliance according to claim 26, wherein a lower edge of said cup lies at most 2 mm below an upper edge of said connector.

28. The refrigeration appliance according to claim 15, comprising an IR-absorbing surface layer on a surface of said siphon facing toward said defrost heater.

29. The refrigeration appliance according to claim 15 configured as a domestic refrigeration appliance.