GB2147401A

GB2147401A - Compressor-type refrigerators

Info

Publication number: GB2147401A
Application number: GB08424508A
Authority: GB
Inventors: Viktor Rohonczy; Istvan Szikszai
Original assignee: Hutogepgyar
Current assignee: Hutogepgyar
Priority date: 1983-09-29
Filing date: 1984-09-28
Publication date: 1985-05-09
Also published as: DE3435794C2; FR2552863A1; HU190165B; AT395352B; DE3435794A1; ATA290984A; FR2552863B1; HUT35084A; DD228886A5; CS244833B2; GB8424508D0; GB2147401B

Abstract

A duct (7) interconnecting the respective heat-exchangers of the two compartments of a compressor- type refrigerator is provided with surface-increasing elements (8) to avoid frosting. The surface- increasing elements (8) are covered by a cover element (9) in metallic connection with the heat exchanger plate (10) of the fresh food compartment. <IMAGE>

Description

SPECIFICATION Heat exchanger for the automatic defrosting of the normal cooling compartment of compressor-type refrigerators with two cooling compartments arranged in the same cabinet The invention relates to a heat-exchanger for the automatic defrosting of the normal cooling compartment of compressor-type refrigerators with two cooling compartments arranged in the same cabinet.

The arrangement according to the invention enables a well-regulated defrosting and removal of hoarfrost under normal operational circumstances without any discrete energy input or electric heating, on the evaporating plate of the fresh food compartment.

It is a well-known fact that in the cooling compartments of domestic refrigerators the moisture contained in the air precipitates on the coldest surfaces, i.e. on the parts of the cooling surfaces on which, in operation, continuously hoarfrost and ice form; this causes considerable problems because thereby the heat transfer capacity of the heat-exchangers is reduced.

Most compressor-type refrigerators in use are provided with an automatically reset, semi-automatic defrosting means. If defrosting becomes necessary, it is necessary (and sufficient) to depress "defrost" button or switch connected to the temperature controller of the apparatus. As a consequence, the compressor is stopped until the heat-exchanger becomes defrosted, then it restarts. Water collected in a collector usually a receptacle of synthetic material is poured out and the receptacle is put back in its place. However, if a user forgets to start the defrost cycle, ice will continue to accumulate on the heat-exchanger and after reaching a certain thickness, it hinders proper operation of the refrigerator; the temperature rises, refrigerated foodstuffs are spoiled and at the same time the power consumption of the refrigerator also rises.

Disadvantages can be eliminated by an automatic defrosting of the refrigerators. Currently, automatic defrosting of the refrigerators is achieved by electric heating.

Defrosting by electric heating involves several disadvantageous features. The heating unit serving for defrosting covers a part of the evaporating surface of the fresh food cooling compartment, and so it prevents natural air flow along and over the evaporating plate.

After each single cooling period a heat quantity Q, is to be introduced into the cooling space for defrosting the fresh food cooling compartment. Under the influence of the heat quantity at thus introduced the freezer compartment and the fresh food cooling compartment are subjected to a temperature fluctuation the extent of which far exceeds the necessary value. the heat quantity at introduced by electric heating is to be dissipated by an extra cooling effect.

The aim of our invention is to eliminate or reduce the drawback of the known solutions and to achieve automatic defrosting of the refrigerator without electric heating and in such a manner that the standardized average energy consumption could be reduced approximately by one quarter.

According to the present invention, there is provided a heat exchanger, or a refrigerator of the compressor-type including such a heat exchanger, comprising heat-exchanger apparatus for the automatic defrosting of one cooling compartment of compressor-type refrigerators having two cooling compartments operated at different temperatures and arranged in the same cabinet, comprising an evaporating plate arranged wholly outside the other of said compartments, a respective heat exchanger element for each said compartment, a duct interconnecting the two heat exchanger elements and surface-increasing elements provided on said duct.

The apparatus according to the invention will be described by means of a preferred embodiment serving as example with the aid of the accompanying drawings, wherein: Figure 1 shows an embodiment of a refrigerator with two cooling compartments provided with an evaporating heat-exchanger and control-technical elements and illustrating the air flow distribution resulting from the arrangement; Figure 2 illustrates in an enlarged view an encircled part of Fig. 3, namely an interconnecting section between the heat-exchangers, provided with surface increasing elements to obtain complete defrosting and removal of hoar-frost, and Figure 3 shows the section according to Fig. 2 disposed inside the cooling compartment.

As may be seen in Fig. 1, a temperature sensor 3 of a temperature controller is arranged in the fresh food cooling compartment 2 disposed in the same cabinet as, but below a freezer compartment 1 corresponding in temperature to the indicated star rating. The sensor 3 is in fact disposed on an evaporating plate 4 of the fresh food cooling compartment 2, and its role is to switch off a motorcompressor 5 at a predetermined value of temperature when the latter drops. In the fresh food cooling compartment the air flow pattern indicated by arrow 6 arises.

At operational standstill, the heat exchanger of the fresh food cooling compartment reacts directly to the higher temperature prevailing in the fresh food compartment and as a consequence, automatic defrosting will take place.

Formation of hoarfrost and ice on the coolant duct 7 inter-connecting the two heat-exchangers due to insufficient surface area may be avoided by a subsequent increase of the heat transfer surface area of this section.

Surface increasing elements 8 and covering element 9 prevent any accumulation of hoarfrost and ice, accordingly the criterion for automatic defrosting is assured.

As may be seen in Figs. 2 and 3, the coolant duct 7 interconnecting the heat exchangers of the freezer and fresh food compartments is connected at both sides to auxiliary anti-icing elements 8 which are covered by a decorative cover element 9 in such a manner that the cover element is also in metallic connection or contact with the heatexchanger plate 10 of the fresh food compartment.

The application of the arrangement according to the invention enables automatic defrosting of domestic or household refrigerators without any energy or power consuming auxiliary device, while enabling removal of hoarfrost and ice far more simply than hitherto.

The technical solution according to the invention can be used for compressor-type refrigerators with freezers of the one, two, three or four-star grades, by a proper choice of the surface area of the evaporating heat-exchanger, keeping the design and dimensions of the cabinet itself identical.

The invention is in no way restricted to the embodiments described and illustrated in the Figures. Within the scope of the claims, other structural solutions for the evaporating means between the two cooling compartments are possible as long as in the function, they comply with the solution according to the invention.

Claims

1. Heat-exchanger apparatus for the automatic defrosting of one cooling compartment of compressor-type refrigerators having two cooling compartments operated at different temperatures and arranged in the same cabinet, comprising an evaporating plate arraned wholly outside the other of said compartments, a respective heat exchanger element for each said compartment, a duct interconnecting the two heat-exchanger elements, and surface-increasing elements provided on said duct.

2. Heat-exchanger apparatus for a compressor-type refrigerator of the kind comprising, in a common cabinet, a frozen food compartment and a fresh food compartment beneath the former, an evaporating plate disposed completely beneath the frozen food compartment, a respective heat-exchanger element for each said compartment, a duct interconnecting the two heat-exchanger elements, and surface-increasing elements provided on said duct.

3. Heat-exchanger apparatus as claimed in claim 1 or 2, wherein both sides of the evaporating plate are provided with heat-transferring surfaces.

4. Heat-exchanger apparatus as claimed in any preceding claim wherein the surface-increasing elements are covered by a cover element in metallic connection with the heatexchanger element of the said one (fresh food) compartment.

5. Heat-exchanger apparatus substantially as herein described with reference to and as shown in the accompanying drawings.

6. A refrigerator including heat-exchanger apparatus as claimed in any preceding claim.