Refrigerator and / or freezer

Abstract

The present invention relates to a refrigeration and / or freezing appliance with a refrigerant circuit comprising an evaporator, a compressor, a condenser and an expansion unit, wherein no dryer is arranged in the line section between the condenser and the expansion valve, and wherein the expansion unit is an expansion valve.

Description

The present invention relates to a refrigeration and / or freezer with a refrigerant circuit which has an evaporator, a compressor, a condenser and an expansion unit, wherein no dryer is arranged in the line section between the condenser and the expansion valve.Such a device is known, for example, from DE 10 2021 204 489 A1. The refrigerant flows through the evaporator and extracts heat from a compartment to be cooled during the evaporation. It then reaches the compressor via a suction line, is compressed by the compressor and is liquefied in the condenser with heat emission. Subsequently, the refrigerant is expanded in the expansion unit in the form of a capillary and then fed back to the evaporator.In the apparatus known from DE 10 2021 204 489 A1, no dryer is provided; instead, it is proposed to add a freezing point-lowering additive or a water-adsorbing agent to the refrigerant or to coat the insides of the tubes of the refrigerant circuit with a material having a drying property.The known device also has an evacuation connection in the line section between the condenser and the capillary.An evacuation connection serves for evacuation of the refrigerant circuit before it is filled with refrigerant. It is tightly sealed after filling with refrigerant.The unit of DE 10 2021 204 49 A1 having the evacuation connection is additionally provided with a particle filter. The particle filter is designed to filter out solid particles from the refrigerant in order to counteract a blockage of the refrigerant circuit and / or an impairment of the operating mode of a component located in the refrigerant circuit.A refrigerant circuit known from the prior art is shown in FIG. 2.Numeral 10 designates the condenser, numeral 20 designates the dryer connected downstream thereof, having a first evacuation connection E1 and numeral 30 designates the capillary. The evaporator 40 is connected downstream of the latter. From the evaporator 40 the refrigerant passes via the suction line into the compressor 50, which is embodied with a second evacuation connection E 2. From the compressor 50, the refrigerant is conveyed back to the condenser 10. The dryer is provided with a particle filter and contains, for example, zeolite for binding water.The object of the present invention is to simplify a cooling and / or freezing appliance of the type mentioned at the beginning.This object is achieved by a refrigeration and / or freezer with the features of claim 1.According to this, it is provided that the expansion unit is an expansion valve.The expansion valve is adjustable, so that depending on the setting of the expansion valve, a different flow cross section is produced through the valve or is available for the refrigerant.In contrast to the capillary known from DE 10 2021 204 489 A1, an expansion valve enables larger inner diameters of the connecting tubes and opens up the possibility of setting the expansion valve at a large flow rate, so that particles and / or ice crystals can be "flushed through" and do not cause blockages and functional disorders.Ice crystals which may form are flushed away on account of the high flow rates and are released again at a warmer point of the refrigerant circuit or by mechanical contact with the inner wall of the refrigerant circuit and thus cannot have an interfering effect. A dryer as an independent component can thus be dispensed with.The expansion valve is arranged between the condenser and the evaporator, so that the sequence condenser-connecting pipe 1-expansion valve-connecting pipe 2-evaporator etc. is present in the relevant section of the refrigerant circuit.Preferably, it is provided that no dryer is arranged in the entire refrigerant circuit.The line section between the condenser and the expansion valve can be formed in one piece, which represents a further simplification. The known embodiment tube-dryer-tube between the condenser and the expansion unit can thus be dispensed with.It is preferred to use a single, one-piece pipe between the condenser and the expansion valve.It is preferred if the expansion valve is operable in a first and a second mode, wherein the first mode is the normal cooling mode and wherein the second mode is a purging mode, wherein the free flow cross section of the expansion valve for the refrigerant is greater in the second mode than in the first mode.A "normal cooling operation" is understood to mean the operation of the device in which the expansion valve is set such that a pressure loss of the refrigerant is achieved by means of the expansion valve, which pressure loss is desired and required for the evaporation of the refrigerant effected in the following evaporator.Compared to this first mode, the expansion valve in this embodiment of the invention is adjustable in (at least one) second mode, which is characterized compared to the first mode in that the expansion valve is still open and thus permits a greater volumetric flow rate and / or a greater flow speed of the refrigerant than in the first mode. As a result, particles and ice crystals are entrained by the refrigerant and can pass through the expansion valve.The advantages are thus no or only a low pressure loss and a good heat exchange with the suction pipe located between evaporator and compressor, since the refrigerant is present in liquid form up to the evaporator.In one embodiment, the line section between the expansion valve and the evaporator and / or between the condenser and the expansion valve is thus in heat-transferring contact with the suction pipe. Since the refrigerant is present in liquid form in these line sections, a particularly good heat transfer to the suction pipe and the evaporated refrigerant located therein results. This has the advantage that the compressor is only charged with gaseous refrigerant.It is conceivable for the flow cross section of the line section upstream of the expansion valve to be circular and to have a diameter of between 1 mm and 5 mm.Furthermore, the flow cross section of this line section can lie in a range between 0.7 mm 2 and 20 mm 2.Corresponding values may also apply to the expansion valve when it is in the second mode.In one possible embodiment, the flow loss in the refrigerant caused by the expansion valve is below 5% in the second mode. In this second mode, the refrigerant therefore does not experience any appreciable pressure loss.In a further embodiment, it is provided that the refrigerant circuit has one, preferably exactly one, evacuation connection. With exactly one evacuation connection, a second evacuation tube is thus saved, which is known from the prior art.This evacuation connection can be located, for example, on the compressor or in the suction pipe located between the evaporator and the compressor.It is particularly advantageous if no particle filter is arranged in the refrigerant circuit. In this embodiment, not only the dryer but also the particle filter are omitted. Such a flow is not necessary, since through the second mode mentioned, such a large flow rate can be achieved that no particles can accumulate, since these are entrained by the refrigerant.In a further embodiment of the invention, it is provided that the device has a control unit which interacts with the expansion valve and which switches the expansion valve from the first mode into the second mode at identical or variable intervals or at a time dependent on at least one parameter.The parameter can be, for example, the start of a cooling cycle which is initiated by the start of the compressor.Other parameters are also conceivable, such as the evaporator temperature. The lower this is, the greater the probability of ice formation by the water located in the refrigerant is and the more frequently the second mode can be selected.It is pointed out at this point that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this represents a possible embodiment, but rather can also denote a plurality of the elements. Likewise, the use of the plural also includes the presence of the element in question in the singular, and conversely the singular also includes a plurality of the elements in question.Furthermore, all features of the invention described herein can be claimed as being combined with one another or isolated from one another as desired.Further details and advantages of the invention are explained in more detail with reference to an exemplary embodiment shown in the drawing.The following are shown: FIG. 1 shows a refrigerant circuit according to the invention, and FIG. 2 : a refrigerant circuit according to the prior art.In FIG. 1, reference numeral 10 designates the condenser and 35 the expansion valve connected downstream thereof, which is adjustable. The evaporator 40 is connected downstream of this evaporator; from the evaporator 40, the refrigerant reaches the compressor 50 via the suction line.From the compressor 50, the refrigerant is conveyed back to the condenser 10.The evacuation port E is located on the compressor 50.In the refrigerant circuit of FIG. 1, there is no dryer and no particulate filter. The term "dryer" is understood to mean a structural unit with a drying agent. The addition of a suspended or liquid drying agent to the refrigerant or the coating of inner sides of walls of the refrigerant circuit with a water-binding coating, e.g. of zeolite, is not excluded according to the invention. However, it is preferred if both or at least one of these variants is dispensed with.As can be seen from FIG. 1, the section between the condenser 10 and the expansion valve 35 is designed in one piece in the form of a single tube. This connecting pipe has a large diameter in the range >1.0 mm and <5.0 mm.The advantages resulting are no or only a low pressure loss and a good heat exchange with suction pipe, since refrigerant is present in liquid form.Apart from this, particles or ice crystals can pass through the connecting pipe and also the expansion valve in its second mode.The expansion valve contains the mechanical option of allowing a large flow rate without appreciable pressure loss. This results in the advantages that the evacuation can take place at one point in the circulation, instead of at two points as in FIG. 2, as well as the advantage that particles and / or ice crystals can pass through.In a preferred embodiment of the invention, a flushing function is provided which can take place regularly (e.g. at the beginning of a cycle). In this scavenging function, the expansion valve is opened further compared to the normal cooling operation, so that a higher flow speed of the refrigerant results.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 204 489 A1 [0002, 0003, 0013]DE 10 2021 204 49 A1

[0006]

Claims

A refrigeration and / or freezer with a refrigerant circuit, which has an evaporator, a compressor, a condenser and an expansion unit, wherein no dryer is arranged in the line section between the condenser and the expansion valve, characterized in that the expansion unit is an expansion valve.Cooling and / or freezing appliance according to claim 1, characterised in that no drier is arranged in the entire refrigerant circuit.Cooling and / or freezing appliance according to claim 1 or 2, characterised in that the line section between the condenser and the expansion valve is formed in one piece.The refrigeration and / or freezer according to any of the preceding claims, characterized in that the expansion valve is operable in a first and a second mode, wherein the first mode is the normal cooling mode and wherein the second mode is a purging mode, wherein the free flow cross-section of the expansion valve for the refrigerant is larger in the second mode than in the first mode.Cooling and / or freezing appliance according to one of the preceding claims, characterised in that the flow cross-section of the pipe leading to the expansion valve is circular and has a diameter between 1 mm and 5 mm.Cooling and / or freezing appliance according to one of the preceding claims, characterised in that the flow cross-section of the pipe leading to the expansion valve lies in a range between 0.7 mm 2 and 20 mm 2.The refrigeration and / or freezer according to any one of claims 4 to 6, characterized in that the flow loss in the refrigerant caused by the expansion valve in the second mode is below 5%.Cooling and / or freezing appliance according to one of the preceding claims, characterized in that the refrigerant circuit has one, preferably exactly one, evacuation connection.Refrigeration and / or freezer according to claim 8da characterised in that the evacuation connection is located on the compressor or in the suction pipe located between the evaporator and the compressor.Cooling and / or freezing appliance according to one of the preceding claims, characterized in that no particle filter is arranged in the refrigerant circuit.Cooling and / or freezing appliance according to one of the preceding claims, characterized in that the pipe leading to the expansion valve is in heat-transferring contact with the suction pipe.A refrigeration and / or freezer according to any one of claims 4 to 11, characterized in that a control unit is provided which interacts with the expansion valve and which switches the expansion valve from the first to the second mode at identical or varying intervals or at a time dependent on at least one parameter.

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