Abstract:
The refrigerating appliance comprises at least one first, second and third refrigerating area for a low, medium or high storage temperature, whereby each refrigerating area has an evaporator ( 24, 25, 26 ). The refrigerating appliance also comprises a compressor ( 19 ), a refrigerant circuit for supplying compressed refrigerant to the evaporators ( 24, 25, 26 ) and for returning expanded refrigerant to the compressor ( 19 ), and comprises at least one switching element ( 22, 22 ′) for directing, as desired, the refrigerant through one of two branches (I, II) of the refrigerant circuit. In the first branch (I), the evaporators ( 24, 26 ) of the first and the third refrigerating areas are connected in series. In the second branch (II), The evaporators ( 24, 25, 26 ) of all three refrigerating areas are connected in series.

Description:
TITLE OF THE INVENTION 
   The present invention relates to a refrigerating appliance with at least three refrigerating areas and evaporators for such a refrigerating appliance. 
   (2) Description of Related Art 
   Such a refrigerating appliance is disclosed in DE 4 242 776 A1. 
   This known refrigerating appliance has two valve units located in the refrigerant circuit and may be activated, in order to channel a refrigerant flow only through an evaporator dedicated to the first refrigerating area called a refrigeration compartment, or subsequently through an evaporator dedicated to the second refrigerating area described as standard refrigeration compartment and the refrigeration compartment evaporator or through a third evaporator dedicated to a refrigerating area described as freezer compartment and the refrigeration compartment evaporator. This means that the refrigerating appliance has three operating modes, a first in which only the refrigeration compartment is cooled, a second, in which the standard refrigeration compartment and the refrigeration compartment are jointly cooled, and a third, in which the freezer compartment and the refrigeration compartment are jointly cooled. The operating times may vary considerably within the three operating modes. Since the chilling department has a relative weak insulation and a small evaporator when compared to the other compartments, the operating time in the third operating mode may clearly exceed that of the second. This leads to a high overall operating time of the refrigerating machine of the refrigeration appliance and therefore to a high-energy consumption and to a lower temperature of the refrigeration compartments than necessary. 
   BRIEF SUMMARY OF THE INVENTION 
   The object of the invention is to define a refrigerating appliance and evaporators for a refrigerating appliance which enables a reduction of the operating time in the third operating mode and thereby prevent super-cooling the refrigeration compartment and reduce the energy consumption of the refrigerating appliance. 
   By connecting the evaporators of all three refrigerating areas sequentially in the second branch of the refrigerant circuit of the refrigerating appliance or by placing the connections on the evaporators so that a series connection of the three evaporators spans between two of the connections will be achieved that the third refrigerating area, the freezer compartment, will also be cooled when the refrigerant flow is routed over the second refrigerating area, the standard refrigeration compartment. The freezer compartment is therefore also continuously cooled when cooling the standard refrigeration compartment, so that the operating time required to adhere to the holding temperature of the freezer compartment is reduced in the third operating mode and therefore also the overall cooling period of the refrigeration compartment. 
   On the other hand, in order to now avoid excessive cooling of the freezer compartment at the expense of the refrigeration compartment, an effective provision may be made so that the second branch of the refrigerant circuit extends only over a section of the surface of the evaporator of the freezer compartment. The size of this section to obtain adequate cooling in all refrigerating areas at minimum power consumption depends on the sections of the individual evaporators and/or on their cooling capacities, as well as on the insulation quality of the individual temperature sectors. A generally effective rule for the size of this surface section can therefore not be defined; however, a suitable value is adjustable per experiment without any difficulty. 
   The evaporator of the third refrigerating area may be arranged in the second branch between the evaporators of the first and the second refrigerating area, so that the evaporated refrigerant partially flows through while the maximum cooling capacity per surface unit of the evaporator accumulates in the particular refrigerating area which is circulated by the refrigerant which is still in a liquid state. 
   Appropriately, the refrigerant circuit further has a third branch, which only contains the evaporator of the first refrigerating area. This third branch may be used when the cooling capacity, which reaches the first refrigerating area over the first or the second branch, is insufficient to maintain its holding temperature. 
   In this case, it may be appropriate that the first and the second branch expand over only a section each of the evaporator surface of the first refrigerating area. If this method assures that the cooling capacity which the first and the second branch in the first refrigerating area develop is somewhat insufficient to adhere their holding temperature, so that occasionally an operation of the third branch is required, a super-chilling of the first temperature section and the therefore accompanying dissipation of energy is therefore impossible. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
     Additional characteristics and advantages of the invention result from the description of implementation examples in the following with reference to the added figures, in which: 
       FIG. 1  shows a perspective of a household refrigeration appliance with three temperature areas for which the submitted invention is applicable, 
       FIG. 2  shows the refrigeration system of the refrigeration appliance in  FIG. 1  in a simplified, schematic illustration, and 
       FIGS. 3 and 4  show examples of evaporators for the refrigeration appliance corresponding with the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a perspective of a household refrigeration appliance  10 , whereof the heat-insulated housing  11  is provided with attached and doors  12 – 14  which open separately at its opening at the edge of the opening edge. Three compartments, which are superimposed and thermally separated by partitions in the interior of the housing  11 , are lockable by the doors  12 – 14  which form the refrigerating areas  15 – 17  for various storage temperatures. The upper refrigerating area which may be locked by door  12  represents a refrigeration compartment, centre section  16 , which is assigned to the door  13 , serves as standard refrigeration compartment, while the section  17  located below is designed as freezer compartment and can be locked with the door  14 . The various storage temperatures in the individual sections are maintained with the assistance of the refrigeration system described in the following. 
   The refrigeration system  18  illustrated schematically in  FIG. 1  has a refrigerant compressor  19  behind which a condenser  20  is located on the pressure side. A dehumidifier cartridge  21  connects to the outlet of the condenser  20 , whose outlet is connected with the inlet of a first valve unit  22 , which is designed as an electromagnetically operated 3/2 way valve. A first outlet of this valve unit is connected to an inlet of an evaporator  26 , which is located in the freezer compartment  17  of the refrigeration appliance. A second outlet of the valve unit  22  is connected to the inlet of a similar second valve unit  22 ′, whose two outlets are always connected with an inlet of an evaporator  25  of the standard refrigeration compartment  16  and/or an evaporator  24  of refrigeration compartment  15 . A spirally wound restrictor  23  which is designed as capillary tube is connected in series between the inlet of one of the evaporators  24 ,  25 ,  26  and the assigned outlet of a valve unit  22 . 
   The outlet of the evaporator  25  is connected by a connecting line between the inlet of the evaporator  26  and the restrictor  23 , which is assigned to it, the outlet of the evaporator  26  is connected in an analog mode with the inlet of the evaporator  24 . 
   The refrigerant circuit therefore has three branches, which are defined as  FIG. 1–111 . All three branches pass through the evaporator  24 , which is assigned, to the refrigeration compartment  15 . The branch in guides the refrigerant initially through the evaporator  26  of the freezer compartment  17 ; branch  111  represents a series connection of all three evaporators in sequence  25 ,  26 ,  24 . 
   A temperature sensor  27 ,  27 ′ and  28  is assigned to each compartment  15 ,  16 ,  17 , whereby, as illustrated schematically in the figure, this may be an optionally installed air temperature sensor  27 ,  27 ′ in the case of the refrigeration compartment  16  and freezer compartment  17 , while the sensor  28  is assigned to the surface of the evaporator  24  in the case of the refrigeration compartment  14 . 
   A regulator assembly  30  controls the operation of the compressor  19 , as well as the switch position of  22 ,  22 ′ by means of measuring signals transmitted over the signal lines  29  by the sensors  27 ,  27 ′,  28 . 
   The regulator assembly  30  moves the refrigerant flow through branch II by means of the measuring signal of the air temperature sensor  27  of the standard refrigeration compartment  16 , so that the temperature in the standard refrigeration compartment  16  is at a value set by the user. When a refrigerant flows through this circuit, the freezer compartment  17  and the refrigeration compartment  15  are also cooled in addition to the standard refrigeration compartment  16 . The cooling capacities of the individual evaporators  24 ,  25 ,  26  are calculated so that the cooling capacity of the evaporators  24 ,  26  are insufficient to cover the cooling requirement of its compartments  15 ,  17  during the thermostat-controlled operation of branch II by means of the measuring signal of sensor  27 . 
   When one of the temperature sensors  27 ,  28  detects a cooling requirement, however, the sensor  27  does not, the regulator assembly  30  will always operate the refrigeration system in the switch position of that for branch  1  or  111 . 
   When the air temperature sensor  27  of standard cooling compartment  16  and one of the air temperature sensors  28 ,  27 ′ simultaneously detect a cooling requirement, arrangements may be made so that the regulator assembly  30  ignores the detected result of the air temperature sensor  28  or  27 ′ until the air temperature sensor  27  no longer reports a cooling requirement. This means that all three compartments are cooled until the standard refrigeration compartment  16  has reached the holding temperature and subsequently continues to cool over one of the branches  1 ,  111  depending on the requirement. Alternative arrangements may be made so that the regulator assembly  30  also considers the deviation of the temperature recorded by the air temperature sensor  28  or  27 ′ of the holding temperature in such an event for the appropriate compartment  15  or  17  and that it changes occasionally to branch I or  111 , if the deviation of the measured temperature is greater than that of the air temperature sensor  27  from the measured holding temperature for the appropriate compartment than depending on the fact if the excessive temperature is present in the freezer compartment  17  or in the freezer compartment  15 , and subsequently again activates the branch when the excessive temperature deviation has been eliminated. 
     FIG. 3  shows a first example of an evaporator in a schematic illustration for the refrigerating appliance described in reference to  FIGS. 1 and 2 . The evaporator contains the abovementioned evaporators  24 ,  25 ,  26 , which are illustrated here assembled on a single support plate, however, which may also be designed as separate components. 
   The branch II enters the evaporator  25  of the freezer compartment at an inlet  31  and meanders essentially over its entire surface to a junction  32  on the evaporator  26  of the freezer compartment. The line coming from the evaporator  25  joins with branch I at this point, which enters the evaporator  26  over an entry connection  33  and from there essentially progresses over the entire surface of the evaporator  26 . The line finally reaches a connecting point  34  on the evaporator  24  of the refrigeration compartment and from there progresses to an outlet  35  over which the refrigerant is returned to the compressor  19 . 
   The line between the connecting point  34  and the outlet  35  cools only a part of the surface of the evaporator  24 , a line, which progresses from an inlet  36  of the evaporator  24  to the connecting point  34  and belongs to branch III, uses the remaining surface. Through suitable selection of the position of the connecting point  34  on the evaporator  24 , it may be defined how large the part of the surface of the evaporator  24  is which is also a part of the branches I and II and therefore is also cooled along with the standard refrigeration compartment  16  and freezer compartment  17 . The cooling capacity in the refrigeration compartment  15  and the hazard of super-cooling of the refrigeration compartment may be limited by this design method during the operation of branches I and II. 
   The evaporators in  FIG. 4  differ from those in  FIG. 3  by the position of the first connecting point  32 . In the case of  FIG. 4 , this is arranged at about half the length of the refrigerant line of the evaporators  26  so that the evaporator  26  of the freezer compartment is only cooled over its entire surface during the operation of branch I, however, only at about half during the operation of branch II. The same deliberations apply here as illustrated in reference to  FIG. 3  for the evaporator  24  of the refrigeration compartment: The cooling capacity of the evaporator  26  may be limited during the operation of branch II by a suitable positioning of the connecting point  32  and thus avoid super-cooling of the freezer compartment during the operation of circuit II. Such a hazard may otherwise develop when the refrigerating appliance is operated at low ambient temperatures.