EP1774231B1 - Domestic refrigerating appliance with an evacuatable storage compartment - Google Patents

Abstract

A domestic refrigerating appliance comprising a heat-insulated inner area, a refrigerating machine using a thermodynamic cycle for refrigerating the inner area, a vacuum pump and a first compartment which is separated from the inner area and which can be evacuated by means of the vacuum pump. The vacuum pump produces pressure inside the first compartment, said pressure being lower than the vapor pressure of water at the temperature of the compartment.

Description

The present invention relates to a household refrigerating appliance having a heat-insulated interior, a refrigerating machine using a thermodynamic cycle for cooling the internal space, a vacuum pump and a first compartment which can be evacuated by the vacuum pump and partitioned from the internal space. Such a refrigerator is eg in DE 198 58 254 A1 described.

The purpose of the evacuation of the compartment is to improve the shelf life of stored foods. For this purpose, during the storage period, a constant low pressure must be maintained. Usually, this pressure is on the order of a few percent of the atmospheric pressure. Its lower limit is determined by the design and quality of the vacuum pump, by the conductance of piping between the compartment and the pump, imperfect tightness of the compartment and piping, etc. Lower pressures are technically feasible without difficulty, but require effort, the Increases the cost of the device in height. Since the maximum achievable storage life of refrigerated goods in a vacuum tray only slightly increases when the final pressure in the compartment under z. B. 1% of the atmospheric pressure is lowered, there is generally no interest in achieving pressures of this magnitude in the vacuum compartment.

A generic household refrigerator is from the JP-A-04 131 674 known.

Object of the present invention is to expand the potential uses of a refrigerator of the type specified above.

This object is achieved by a refrigerator with the features of claim 1. When the vacuum pump in the first compartment (10) produces a final pressure below the vapor pressure of water at the temperature of the compartment (10), water present in the compartment will boil ". The evaporation of the water at low pressure leads to the cooling or cooling of standing with the water in thermal contact refrigerated goods, so that in the evacuated compartment a cooling temperature below that can be reached, which is provided by the refrigerator to the interior. It is particularly preferred if the possibility is created in this way to cool the compartment below the freezing point of water, even if the temperature of the remaining interior of the refrigeration device is higher. For this purpose, the vacuum pump must be able to produce a pressure of 6 mbar or less in the compartment.

The cooling capacity depends on the volume flow extracted from the compartment. In order to achieve a practical cooling performance, the vacuum pump should exhibit a pumping speed of at least 0.5 l / s at the evacuation port of the compartment while in the first compartment a pressure below the vapor pressure of water at the temperature of the compartment prevails.

Refrigerated material other than water may be accommodated in the second evacuatable compartment which is in direct thermal contact with the first compartment.

This second compartment is evacuable independently of the first one, that is, gas contained therein can be pumped while the first compartment is separate from the pump, or vice versa. So it is e.g. possible to evacuate after loading with chilled goods first both compartments and after a certain time or reaching a certain pressure to separate the second compartment of the pump, either to have more suction power for the first available, or to a Dehydration of the refrigerated goods in the second compartment by continuously pumping out the water vapor emitted by it. It is also conceivable to initially evacuate only the second compartment with the refrigerated goods and then turn on the pump to the first compartment, so as to set the cooling in motion.

Since water vapor should not be released to the same extent in the second compartment as in the first compartment, the pumping speed at an evacuation port of the second compartment may be kept smaller than that of the first compartment.

To realize a direct thermal contact between the two compartments and to ensure that they are thermally more closely coupled with each other than with a remainder of the interior, both compartments are surrounded by a common wall.

The first compartment may advantageously contain a hydrophilic porous material to provide a large surface area from which water can evaporate.

In order to avoid that water vapor pumped from the vacuum pump recondensed at an inappropriate place, and / or to trap oil vapors of the vacuum pump, a condensate separator may be connected to the vacuum pump.

Conventionally, most refrigeration appliances have an evaporation tray, which is fed with condensate water which precipitates on the evaporator of the refrigerator in the interior of the refrigeration appliance. Such an evaporation tray can also be used for dewatering the condensate.

Figs. 1 und 2

jeweils in einem schematischen Schnitt Kältegeräte, wobei dasjenige gemäß Figur 2 ein Kältegerät gemäß der Erfindung zeigt.

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

Figs. 1 and 2

in each case in a schematic section refrigerators, wherein the one according to FIG. 2 a refrigerator according to the invention shows.

Fig. 1 shows a schematic section through a household refrigerator with a body 1 and hinged to the body 1 door 2, which enclose a thermally insulated interior 3. In a lower rear corner of the body 1, a niche 4 is formed, which receives the compressor 5 of a refrigerator of the refrigerator in a conventional manner. The compressor 5 feeds a condenser 6 attached to the rear wall of the body 1 with high-pressure refrigerant; The refrigerant reaches from there via a throttle point attached to the rear wall of the interior 3 evaporator 7 and flows from the latter to the compressor 5 back.

In the niche 4, a vacuum pump 8 is further included, the suction port is connected via a pipe 9 with an evacuated compartment 10. The compartment 10 is shown here approximately at half the height of the interior 3, but can also be placed at any other location; in particular an attachment near the bottom of the interior is to be considered, in order to keep the pipe 9 short and thus to allow an effective evacuation of the compartment 10.

The compartment 10 has on its front side facing the door 2 a flap 11 which can be opened in the non-evacuated state of the compartment 10 in order to load or unload refrigerated goods. The flap 11 and the remaining walls of the compartment 10 each contain an insulating layer which thermally insulates the interior of the compartment 10 from the surrounding interior space 3.

Inside the compartment 10, a saucepan 12 is shown by way of example with a loose lid. Around the pot 12, a water-soaked cloth 13 is looped.

When the compartment 10 is evacuated, the air also escapes from the interior of the pot 12, since its lid rests only loosely. However, when the pressure in the compartment 10 approaches the final pressure in the range of a few millibars or fractions of a millibar, hardly any gas exits the pot 12, so that in the interior, when it contains water-containing refrigerated goods, a pressure setting essentially corresponds to the vapor pressure of water at the temperature of the pot 12. Excessive dehydration of the pot contents is thus avoided. When evacuating the compartment 10, if the pressure in the compartment falls to the vapor pressure of the water, the water with which the cloth 13 is soaked will begin to "boil".

At a temperature of compartment 10 of 0 ° C, the vapor pressure of the water is 6 mbar. One liter of water vapor at this pressure weighs 5 mg, and at a heat of vaporization of the water of 2250 J / g, 11 J is required to produce it. If the pump at the suction port 14 of the tray 10, at the mouth of the pipe 9, a pumping speed of 1 l / s unfolds, it drains the subject content per second, a heat amount of 11 J, ie it develops a cooling capacity of 11 W. If you cold losses neglected over the walls of the compartment 10, this means that at a heat of fusion of the water of 335 J / g 50 minutes are required to freeze 100 g of water from 0 ° C. It is thus possible, for example, to produce ice cubes with the refrigerator according to the invention by placing an ice cube tray in the compartment 10 and evacuating it, without the refrigerator having to be able to produce temperatures below 0 ° C. in the interior 3. By setting the pump's pumping speed higher at port 14, one can achieve shorter cooling times in proportion to the pumping speed as needed.

To a high pressure port of the vacuum pump 8, a condensate 16 is connected via a second pipe 15. A sewer line 17 leads from the Kondensatabscheider 16 to an evaporation tray 18, which is mounted in a conventional manner on the compressor 5 to be heated by its waste heat, and also collected on the evaporator 7, through a bore of the body 1 from the interior 3 derived condensed water fields.

The embodiment of Fig. 2 is different from that of Fig. 1 in two independently realizable aspects.

The first aspect is that the refrigerator comprises a second evacuatable compartment 19 which is separated from the compartment 10 by a thin, heat-permeable partition 20 and together with this is surrounded by an insulating outer wall 21 which separates the compartments 10, 19 from the remainder of the compartment Interior 3 separates.

The pipe 9 opens at the suction port 14 in the lower compartment 10; a shut-off valve 22 in the intermediate wall 20 allows the two compartments 10, 19 to be separated from one another or connected to one another for evacuation. In Fig. 2 each compartment 10, 19 is assigned its own flap 11; but they could also be closed by a common flap. The compartment 10 can be loaded with chilled goods, or it can be charged with water, which alone serves to generate evaporative cooling during evacuation. The water can be incorporated in the form of a water-filled shallow dish or, preferably, in conjunction with a porous hydrophilic material such as cloth, fleece or foam which provides a large surface area for the evaporation of the water.

The second difference lies in the attachment of the evaporation tray 18, which in Fig. 2 is not mounted on the compressor 5, but in a base portion 23 of the refrigerator below the heat-insulating bottom of the body 1, is housed. This base portion 23 further includes a fan 24 and a condenser 25, which is placed between the fan 24 and evaporation tray 18, that at the condenser 25 heated air blown over the water surface of the evaporation tray 18 passes.

Claims (9)

1. Domestic refrigerating appliance with a thermally insulated interior space (3), a refrigerating machine (5, 6, 7), which uses a thermodynamic circuit process, for cooling the interior space (3), a vacuum pump (8), a first compartment (10) which is evacuatable by the vacuum pump (8) and which is partitioned off from the interior space (3), wherein the vacuum pump (8) is in a position of generating in the first compartment (10) an end pressure below the vapour pressure of water at the temperature of the compartment (10), characterised in that the domestic refrigerating appliance comprises a second evacuatable compartment (19) in direct thermal contact with the first compartment (10), that the first compartment (10) and the second compartment (19) are surrounded by a common wall (21), that the second compartment (19) is separated from the first compartment (10) by a thin heat-permeable intermediate wall (20) and that the first compartment (10) is evacuatable independently of the second compartment (19) in that a blocking valve (22) in the intermediate wall (20) makes it possible to separate the first compartment (10) and the second compartment (19) from one another for the evacuation or to connect them together.
2. Domestic refrigerating appliance according to claim 1, characterised in that the end pressure is below 6 millibars.
3. Domestic refrigerating appliance according to claim 1 or 2, characterised in that the vacuum pump (8) develops at an evacuation connection (14) of the first compartment (10) a suction capacity of at least 0.5 I/s at a pressure, which prevails in the first compartment (10), below the vapour pressure of water at the temperature of the compartment (10).
4. Domestic refrigerating appliance according to any one of the preceding claims, characterised in that the suction capacity of the pump (8) at an evacuation connection of the second compartment (19) is smaller than at that of the first compartment (10).
5. Domestic refrigerating appliance according to any one of the preceding claims, characterised in that the first compartment (10) contains a hydrophilic porous material (13).
6. Domestic refrigerating appliance according to any one of the preceding claims, characterised in that a condensate separator (16) is connected with the vacuuum pump (8).
7. Domestic refrigerating appliance according to claim 6, characterised in that the refrigerating appliance comprises an evaporation basin (18) in which water is removed from the condensate separator (16).
8. Domestic refrigerating appliance according to claim 7, characterised in that the evaporation basin (18) is heated by loss heat of the refrigerating machine.
9. Domestic refrigerating appliance according to any one of the preceding claims, characterised in that it is a refrigerator.

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