Evaporator for a refrigeration device

The present invention relates to an evaporator for a refrigeration device. The surface of a reaches such an evaporator, when it is supplied with refrigerant temperatures below 0 ° C. Humidity from the interior of the refrigerator can therefore on the surface of Evaporator condense and freeze. This produces at the surface of evaporator first a thin, evenly distributed Reif layer, unless it is defrosted in the meantime, during the operation of the refrigerator a increasing thickness and finally reached coalesces into a solid, rigid layer of ice. Since the temperature of Evaporator in the course of time varies, depending on whether it with refrigerant is supplied or not, this ice expands during the Time periodically and contracts again. In this building Tensions between the ice and the lying underneath Evaporator, which finally lead to a jerky slipping of ice. The resulting therefrom pops be disturbing perceived.

Object of the present invention is an evaporator for provide a refrigeration device, wherein these pops are reduced.

The object is achieved in that the surface the evaporator at which ice could form, with a hydrophobic Coating is provided.

Such a coating is effective, order on an ice-free evaporator forming the first ice crystals delay and so to extend the time, which is required until after a defrost operation a quantity of ice has accumulated on the evaporator. The is strong enough to cause cracking noises. A further effect of the hydrophobic layer is that they form the a homogeneous layer of frost on the surface of the evaporator is prevented. Instead, the icing does not begin on a small number of unavoidable germs on the surface of the evaporator. Which there forming Eisperlen grow more or less evenly on its entire surface and achieve a substantial Thickness before they begin to coalesce. That is, it can a large in comparison with a non-hydrophobic evaporator amount of ice Evaporator invention gather before a coherent Layer is formed which is able to generate clicking sounds.

Another advantage of the island growth the ice is that surface areas remain the evaporator relatively long ice-free and effective heat exchange between the refrigerant and Near the evaporator will still enable when other Areas of the evaporator surface already a substantial amount Ice has accumulated. The time interval between two defrosting phases can therefore longer chosen be required in a non hydrophobic evaporator, which for the user one with an evaporator according to the invention equipped refrigerator a gain comfort and a reduction in the energy consumption of the refrigeration device and thus its operating cost includes.

The hydrophobic coating may preferably a silicone as hydrophobisierend acting constituent contain.

The coating can be solidified as a Lacquer layer or oil layer be applied. The oil layer has the particular advantage that it, since it does not in itself is determined, the displacement of the forming of Eisperlen the surface the evaporator favors, so that even when fully Evaporator icing with a layer thickness in a conventional Evaporator for producing cracking noises sufficient when this reduced inventive evaporator are there for a displacement of the crust with respect to the evaporator no high thermal stresses must be built that erupt in loud cracking noises, but a substantially lower voltage is sufficient to the ice to let slip on the evaporator with respect or possibly even a continuous sliding of the ice on the evaporator comes about.

Preferably, the evaporator according to the invention is constructed as a lamellar evaporator for use in itself a Convection cooling or freezer suitable.

The accompanying figure shows a schematic view a partially frozen section of a lamellar evaporator invention <figref>4</figref>, The finned evaporator <figref>4</figref> comprises a pipe <figref>1</figref>, the in operation of refrigerant flows through becomes. Around the outer surface of the pipe<figref>1</figref> is a lamella <figref>2</figref> helically wound. The lamella<figref>2</figref> and the outer surface of the tube <figref>1</figref>Where the lamella <figref>2</figref> mounted form, the heat exchange effective surface the lamellar evaporator and with a hydrophobic coating of a silicone oil provided.

Due to the hydrophobicity of the coating is a much more energy is required to the surface of the lamellar evaporator <figref>4</figref> to wet, and this energy must free, when on the surface Moisture freezes. This is a major obstacle to the formation of ice crystals on the surface. A considerable Percentage of humidity of a flowing past the finned evaporator &lt;?page 3?&gt;airstream therefore condenses on the evaporator fins <figref>4</figref> even if not when the air flow with moisture is supersaturated, simply because the moisture encounters no surface to which a freezing energetically favorable would. Of the fin evaporator <figref>4</figref> causes, therefore, when he or in a forced air used no-frost refrigerating appliance is only a slight drying of the air in the interior of the refrigerator, which for the Storage of perishable foods such as fresh vegetables entirely desirable is.

Thus humidity in the air evaporator <figref>4</figref> condensed, have to because surface areas be present, in which the condensation is energetically favorable. Such sites are usually condensation nuclei in the form of dust particles, Obertlächenunstetigkeiten or the like, on the surface of the lamellar evaporator inevitably exist, but only a very small Part of their make up. These condensation nuclei form - as in<figref idrefs="S5">1</figref> shown - in operation the lamellar evaporator a variety of compact Eisperlen <figref>3</figref>, On the surface this Eisperlen <figref>3</figref> condensed preferably more moisture from the finned evaporator <figref>4</figref> the surrounding air, so that the pearls <figref>3</figref> over time in thickness and diameter increase, while lying between the bead portions of the surface of the lamellar evaporator <figref>4</figref> length Time remain ice-free and efficient heat exchange between the evaporator fins <figref>4</figref> circulating refrigerant and allow the surrounding air.