Patent Publication Number: US-6655170-B2

Title: Refrigerator

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of copending International Application No. PCT/EP00/10556, filed Oct. 26, 2000, which designated the United States. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a refrigerator with a heat-insulating housing, within which are provided at least two refrigerating compartments that are separated from one another in a heat-insulating manner, have a different freezing-compartment temperature, and that are in each case cooled by an evaporator of corresponding refrigerating capacity. Each of the evaporators has a preceding throttle device on the inflow side. Each of the evaporators are acted upon by at least one activating device, in each case separately, with refrigerant that is positively circulated by a refrigerant compressor having on the suction side preceding refrigerant collector and that, when the refrigerant compressor is in the standstill phase, is collected, at least for a particular part, in a refrigerant routing portion of the evaporator having a higher refrigerating capacity. 
     In cooling and freezing combinations with a single compressor, existing prior art refrigerators, for example, cool their cooling and freezing compartment respectively by evaporators interlinked in a series connection, the cooling-compartment evaporator preceding the freezing-compartment evaporator in the series connection. However, such an interconnection of the evaporators does not allow separate regulation of the two refrigerating compartments. Accordingly, there has been a move, in the case of cooling and freezing combinations equipped with a single compressor, toward placing the cooling-compartment evaporator and the freezing-compartment evaporator in a parallel connection with one another. Although such a configuration allows separate temperature regulation of the compartments cooled by these evaporators, nevertheless, the result of such an interconnection is that, during the standstill time of the refrigerant compressor in the freezing-compartment evaporator, a particular displacement of refrigerant toward the freezing-compartment evaporator commences due to the temperature and pressure difference in relation to the cooling-compartment evaporator. Consequently, when there is a demand for cold in the cooling compartment, only reduced refrigerant quantity is available for cooling the cooling-compartment evaporator and, therefore, either delay times or even malfunctions may occur. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a refrigerator that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that, by simple structural measures, is configured such that, on one hand, the disadvantages of the prior art are avoided and, on the other hand, separate temperature regulation of the refrigerating compartments becomes possible. 
     With the foregoing and other objects in view, there is provided, in accordance with the invention, a refrigerator including a heat-insulating housing having at least two refrigerating compartments separated from one another in a heat-insulating manner, each of the compartments having a different compartment temperature, evaporators each respectively cooling one of the compartments, and each having a given different refrigerating capacity and containing a liquid refrigerant, at least one of the evaporators having a relatively higher refrigerating capacity and a refrigerant routing portion having a refrigerant reception volume, throttles each respectively fluidically connected upstream of one of the evaporators with respect to a refrigerant flow direction, a refrigerant compressor having a suction side and a standstill phase, the compressor fluidically connected to the throttles and to the evaporators for circulating the refrigerant through the throttles and the evaporators, a refrigerant collector fluidically connected to the suction side of the refrigerant compressor, the refrigerant collector collecting an amount of the refrigerant when the compressor is in the standstill phase, more than a majority of the reception volume of the refrigerant routing portion being filled with the refrigerant in the standstill phase of the compressor, and at least one activating device fluidically connected to each of the evaporators, the activating device positively and separately controlling circulation of the refrigerant through each of the evaporators. 
     According to the invention, the refrigerant routing portion is constructed, in terms of its refrigerant reception volume, for at least substantially filling with liquid refrigerant in the standstill time of the compressor, in particular, for at least approximately completely filling with liquid refrigerant in the standstill time of the compressor. 
     To avoid disadvantages of the prior art, the invention proposes that the refrigerant routing portion of the freezing-compartment evaporator, the refrigerant routing portion serving for collecting the liquid refrigerants, be dimensioned, in terms of its reception volume, such complete filling with liquid refrigerant in the standstill time of the compressor is achieved. What is achieved thereby is that, when there is a demand for cold by the cooling compartment, the liquid refrigerant is available immediately for the refrigerating circuit of the cooling compartment. 
     By configuring the freezing-compartment evaporator according to the invention, when there is a demand for cold in the cooling compartment, during the start-up of the refrigerant, compressor pressure is exerted on the liquid refrigerant that has accumulated in the refrigerant routing portion during the standstill time of the refrigerant compressor. As a result, directly after the start-up of the compressor, such refrigerant is transported out of the freezing-compartment evaporator into a refrigerant collector and is available from the collector for cooling the cooling-compartment evaporator. Due to the complete filling of the evaporator portion of the freezing-compartment evaporator, the evaporator portion serving for collecting liquid refrigerant during the standstill phase of the refrigerant compressor, a pressure difference acts on the accumulated liquid refrigerant during the start-up of the compressor. As a result, the liquid refrigerant is then “entrained” out of the freezing-compartment evaporator and is, therefore, fed extremely quickly to the refrigerating circuit serving for cooling the cooling-compartment evaporator. 
     In accordance with another feature of the invention, the refrigerant reception volume of the refrigerant routing portion is dimensioned smaller than the quantity of liquid refrigerant that accumulates during the standstill time of the refrigerant compressor in the evaporator having a higher refrigerating capacity. Such a configuration gives cost-effective rise to extremely reliable operation for the separate regulation of the freezing compartment and the cooling compartment that, moreover, can also be switched off individually due to their separate regulatability. 
     The evaporator having a higher refrigerating capacity is configured particularly advantageously when, in accordance with a further feature of the invention, the evaporator of higher refrigerating capacity is configured as a freezing-compartment evaporator, of which the refrigerant routing portion lying lowest in the operating position of the refrigerator is dimensioned smaller, in terms of its refrigerant reception volume, than the refrigerant quantity accumulating there in the standstill time of the refrigerant compressor. With regard to an evaporator manufactured from a composite plate structure, complete filling of the refrigerant routing portion can be achieved, for example, by a corresponding reduction in the duct cross section. 
     In accordance with an added feature of the invention, the evaporator of higher refrigerating capacity is configured as an evaporator system with a plurality of evaporator levels disposed at a distance one above the other. Preferably, one of the evaporator levels is a lowest evaporator level at the lowest point. For such evaporators, both plate-like evaporator levels and what are referred to as wire-tube evaporators have proved appropriate. In the latter type of evaporators the refrigerant routing portion filled at least completely with liquid refrigerant in the standstill time of the compressor is formed by a meandering tube portion. 
     In accordance with an additional feature of the invention, the refrigerant collector is embedded into the heat-insulation material of the heat-insulating housing. Thereby, defrosting of the refrigerant collector when the cooling-compartment evaporator is acted upon with liquid refrigerant is prevented in a simpler reliable way. 
     In accordance with yet another feature of the invention, the heat-insulation material separates the at least two refrigerating compartments from one another. 
     In accordance with a concomitant feature of the invention, the refrigerant collector is disposed in the interception region of a condensation interception channel provided for collecting the melt water occurring at the evaporator of lower refrigerating capacity. By virtue of such a configuration of the refrigerant collector, there is no need for heat insulation to avoid the defrosting of the latter because the condensation water occurring in the event of a defrosting of the refrigerant collector is introduced directly into the already existing condensation water interception channel. 
     Other features that are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a refrigerator, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic, partially cross-sectional perspective view of a cooling and freezing configuration according to the invention, of which the cooling compartment and the freezing compartment are cooled separately by evaporators disposed in a parallel connection and the freezing-compartment evaporator is filled, at its portion near the bottom, at least approximately completely with liquid refrigerant in the standstill stage of the refrigerant compressor; and 
     FIG. 2 is an exploded cross-sectional view of a duct portion of the freezing-compartment evaporator filled with liquid refrigerant indicated by a solid circle near the bottom of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a simplified diagrammatic illustration of a cooling and freezing combination  10  having a heat-insulating housing  11 . 
     The interior of the housing  11  is subdivided by a horizontally disposed, heat-insulating, intermediate wall  12  into two portions. The higher portion is a cooling compartment  13 . The intermediate wall includes a condensation water interception channel  34  for collecting melt water. For cooling the cooling compartment  13 , a plate-like evaporator is provided, which has a refrigerant duct  15  having a refrigerant injection point  16  at an inflow-side end. 
     Provided within the heat-insulating housing  11  below the cooling compartment  13 , so as to be separated from the cooling compartment  13  by the intermediate wall  12 , is a freezing compartment  17  that is cooled by an evaporator  18  configured, for example, as a wire-tube evaporator and, in the present case, having three evaporator levels  19 ,  20 , and  21  disposed at a vertical distance one above the other and generated by the corresponding shaping of a single tube conduit. Of the evaporator levels  19  to  21 , the evaporator level  21  near the bottom possesses, like the other two evaporator levels  19  and  20 , a refrigerant routing portion  22  that is formed from a continuously running tube conduit having a meandering shape and that, by virtue of its dimensioning, to be precise, the inside diameter and the length of the portion  22 , has a refrigerant reception volume that ensures at least a complete filling of the refrigerant routing portion  22  with liquid refrigerant  23  (see, in this respect, FIG. 2) in the standstill time of a compressor, which is explained in more detail below. 
     The refrigerant routing portion  22 , which has an installation position conducive to its complete filling, is followed by a connecting conduit  24  issuing at a branch point  25 , to which the outflow-side end of the cooling-compartment evaporator  14  is also routed. The branch point  25  is connected through a connecting conduit  26  to a refrigerant collector  27 , configured as a steam dome, which is embedded into the heat insulation of the intermediate bottom  12  to avoid defrosting in the cooling mode of the cooling-compartment evaporator. The refrigerant collector  27  is connected through a suction conduit  28  to a refrigerant compressor  29  connected on the delivery side to a condenser  30 . An outlet side of the condenser  30  is connected, for example, to an electrically activatable 3/2-way solenoid valve  31 . The 3/2-way solenoid valve  31  serves to control the refrigerant  23 , positively circulated by the refrigerant compressor  29 , toward the evaporators  14  and  18 . 
     In a first control position I, the solenoid valve  31  deflects the liquid refrigerant  23  through a throttle  32  toward the freezing-compartment evaporator  18 , where it is routed through the levels  19  to  21  of the evaporator  18  for cooling. When the refrigerant compressor  29  is in operation, the refrigerant  23  flows from the outflow-side end of the evaporator level  21  through the connecting conduit  24  toward the branch point  25  and, from there, to the refrigerant collector  27  and into the suction conduit  28  connected to the refrigerant compressor  29  on the suction side. 
     In addition to the control position I, the solenoid valve  31  possesses another control position II, in which the positively circulated liquid refrigerant  23  is fed, through a throttle  33  preceding the evaporator  14 , to the evaporator  14 , from which the refrigerant  23  is fed at the outflow-side of the evaporator  14 , through the branch point  25  and the refrigerant collector  27 , and through the suction conduit  28 , again to the refrigerant compressor  29 . 
     In the event that a demand for cold by the cooling compartment  13  is signaled after a standstill of the refrigerant compressor  29 , when the refrigerant compressor  29  is restarted due to the temperature demand of the cooling compartment  13 , the liquid refrigerant  23  that is accumulated in the refrigerant reception volume of the refrigerant routing portion  22  during the standstill phase of the refrigerant compressor  29  is entrained out of the refrigerant routing portion  22  and is conveyed into the steam dome that serves as a refrigerant collector  27  and where, by activation through the control position II of the solenoid valve  31 , the refrigerant  23  is then available to the refrigerating circuit for cooling the cooling compartment  13 . Due to the immediate activation of the liquid refrigerant  23  that, as a consequence of the principle employed, accumulates in the freezing-compartment evaporator  18  during the standstill phase of the refrigerant compressor  29  (in contrast to the prior art in which the refrigerant  23  that is accumulated in the freezing-compartment evaporator  18  during the standstill phase of the refrigerant compressor is fed only gradually to the cooling-compartment refrigerating circuit), the refrigerant  23  is transferred into the cooling-compartment  13  refrigerating circuit extremely quickly. As a result, the intended temperature in the cooling compartment  13  is reached markedly sooner, as compared with the prior art, and, therefore, the energy balance of the cooling and freezing combination is markedly improved.