Abstract:
A refrigerating system for a refrigerator is disclosed. The refrigerator includes a compressor that compresses refrigerant, a condenser connected to the compressor that condenses compressed refrigerant, an expansion valve connected to the condenser that expands condensed refrigerant, freezing chamber and refrigerating chamber evaporators connected to the expansion valve that cool air in a freezing chamber and a refrigerating chamber by using refrigerant, respectively, and a regulating valve between the condenser and the refrigerating chamber evaporator that regulates refrigerant supply to the refrigerating chamber evaporator, thereby providing a refrigerating system for a refrigerator having high efficiency.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to refrigerating systems for refrigerators, and more particularly, to a control method at the time of initial operation of a refrigerating system. 
   2. Discussion of the Related Art 
   In general, the refrigerator cools a space thereof for fresh storage of food therein for a time period while refrigerant (working fluid) repeats a refrigerating cycle of compression-condensing-expansion-evaporation. 
   Of the refrigerators, a direct cooling type refrigerator is provided with separate evaporators for a freezing chamber and a refrigerating chamber respectively. The direct cooling type refrigerator will be described in detail with reference to  FIG. 1 . 
   The refrigerating system of the direct cooling type refrigerator is provided with a compressor  11 , a condenser  12 , an expansion valve  13 , a freezing chamber evaporator  14 , and a refrigerating chamber evaporator  15 . Various units of the refrigerating system are connected with refrigerant pipes  16 . 
   The compressor  11  compresses low temperature/low pressure refrigerant gas to a high temperature/high pressure refrigerant gas. The condenser  12  receives and compresses refrigerant from the compressor  11 . The expansion valve  13  receives refrigerant from the condenser  12  and drops a pressure of the refrigerant. The freezing chamber evaporator  14  and the refrigerating evaporator  15  evaporate the refrigerant from the expansion valve  13  in a low pressure state, to absorb heat from air in the vicinity of the evaporators  14 , and  15 . Air cooled down by the evaporators  14 , and  15  is supplied to the freezing chamber and the refrigerating chamber for fresh storage of food. Above cycle is repeated continuously while the refrigerator is operated. 
   However, the substantially long refrigerant pipes  16  of the refrigerating system of the related art direct cooling type refrigerator due to the two evaporators  14 , and  15  requires large quantity of refrigerant filled in the refrigerating system. Therefore, even though a high torque is not required for the compressor  11  once operation of the refrigerating system is stabilized after the refrigerating system is operated for a certain time period, a high torque, with consequential high voltage, is required when the refrigerating system starts operation, i.e., the compressor  11  starts operation. That is, the related art refrigerating system uses a compressor of which torque is high unnecessarily due to above initial operation problem. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a refrigerating system that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
   An object of the present invention is to provide a refrigerating system which can drop a torque and a voltage required for a compressor at starting of operation. 
   Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a refrigerating system for a refrigerator includes a compressor for compressing refrigerant, a condenser connected to the compressor for condensing compressed refrigerant, an expansion valve connected to the condenser for expanding condensed refrigerant, freezing chamber, and refrigerating chamber evaporators connected to the expansion valve for cooling air in a freezing chamber and a refrigerating chamber by using refrigerant respectively, and a regulating valve between the condenser and the refrigerating chamber evaporator for regulating refrigerant supply to the refrigerating chamber evaporator. 
   The regulating valve is configured such that the refrigerant supply to the refrigerating chamber evaporator is permitted, selectively. In such a selective refrigerant supply, at first, the regulating valve cuts off the refrigerant supply to the refrigerating chamber evaporator when the compressor is operated initially. Moreover, the regulating valve permits the refrigerant supply to the refrigerating chamber evaporator when operation of the compressor is stabilized. For an example, the regulating valve may permit the refrigerant supply to the refrigerating chamber evaporator when a predetermined time period passes after operation of the compressor starts, or a torque of the compressor becomes constant. 
   Alternatively, the regulating valve may be configured such that the regulating valve increase the refrigerant supply to the refrigerating chamber evaporator gradually after operation of the refrigerating system starts. In this case, the regulating valve is valve configured to regulate a degree of opening of a flow passage connected to the refrigerating chamber evaporator. 
   The expansion valve includes a first expansion valve for expanding refrigerant to the freezing chamber evaporator, and a second expansion valve for expanding refrigerant to the refrigerating chamber evaporator. In this case, more specifically, the regulating valve is provided between the refrigerating chamber evaporator and the second expansion valve. 
   Thus, the present invention enables to reduce a production cost of the refrigerating system and increases efficiency of the refrigerating system. 
   It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings; 
       FIG. 1  illustrates a diagram of a related art refrigerating system of a refrigerator, schematically; 
       FIG. 2  illustrates a diagram of a refrigerating system of a refrigerator in accordance with a preferred embodiment of the present invention; and 
       FIG. 3  illustrates a flow chart showing the steps of a process for operating a refrigerating system in accordance with a preferred embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     FIG. 2  illustrates a diagram of a refrigerating system of a refrigerator in accordance with a preferred embodiment of the present invention, and  FIG. 3  illustrates a flow chart showing the steps of a process for operating a refrigerating system in accordance with a preferred embodiment of the present invention. 
   The refrigerating system of the present invention includes a refrigerant pipe  160 , a compressor  110 , a condenser  120 , a freezing chamber expansion valve  131 , a refrigerating chamber expansion valve  132 , a freezing chamber evaporator  140 , and a refrigerating chamber evaporator  150 , and a regulating valve  170 . 
   Basically, the refrigerant pipe  160 , the compressor  110 , and the condenser  120  are the same with the related art. The refrigerant pipe  160  guides refrigerant to various units of the refrigerating system, the compressor  110  is connected to the refrigerant pipe  160  for compressing refrigerant flowing through the refrigerant pipe  160 , and the condenser  120  condenses refrigerant compressed at the compressor  110 . 
   However, in the present invention, the expansion valves  131 , and  132  are connected to the evaporators  140 , and  150  respectively, and supply of refrigerant to the refrigerating chamber expansion valve  132  connected to the refrigerating chamber evaporator  150  is made selectively. For such a supply, the regulating valve  170  is mounted in the refrigerating pipe  160  connecting the condenser  120  and the refrigerating chamber evaporator  150 . Particularly, it is preferable that the regulating valve  170  is mounted between the condenser  120  and the refrigerating chamber expansion valve  132  for making selective flow of refrigerant to the refrigerating chamber expansion valve  132 . 
   In accordance with signals from a regulating valve controller  170 A, the regulating valve  170  opens/closes the refrigerant pipe  160  selectively, for regulating supply of the refrigerant to the refrigerating chamber evaporator  150 . In more detail, at an initial operation of the refrigerating system, the regulating valve  170  cuts off refrigerant flow to the refrigerating chamber evaporator, specifically, to the refrigerating chamber expansion valve  132 . According to this, in the refrigerating system of the present invention, a circulating distance of refrigerant becomes the shortest, and a voltage and a torque required for starting of the compressor  110  are minimized, accordingly. 
   For regulating the circulating distance of the refrigerant, though not shown, the regulating valve  170  may regulate refrigerant supply to the freezing chamber evaporator  140  instead of the refrigerating chamber evaporator, or refrigerant supply both to the refrigerating chamber and the freezing chamber  140 , and  150 . However, in general, since it is required that a temperature of the freezing chamber is maintained lower than a temperature of the refrigerating chamber, it is required that expanded refrigerant is supplied to the freezing chamber evaporator  140  at first. Under this reason, it is not preferable to cut off an initial refrigerant supply to the refrigerating chamber evaporator  150  for stable operation of the refrigerating system. Therefore, as described, the cutting off of the initial refrigerant supply to the refrigerating chamber evaporator  150  is advantageous both in view of making the refrigerant circulating distance the shortest, and stability of the refrigerating system operation. 
   The steps of operation of the refrigerating system of the direct cooling type refrigerator of the present invention will be described in detail, with reference to  FIG. 3 . 
   Upon putting the refrigerating system into operation, the compressor  110  is started to compress refrigerant. The torque and voltage required for starting the compressor  110  is dependent on a length of the refrigerant pipe  160 , particularly, a refrigerant circulating distance. 
   In the present invention, when operation of the refrigerating system is started, i.e., when initial starting of the compressor  110  is made, the refrigerant chamber expansion valve  132  is closed by the regulating valve  170 , to shorten the refrigerant flow distance in the refrigerating system, significantly. That is, the refrigerant flows not through the refrigerating chamber expansion valve  132  and the refrigerating chamber evaporator  150 , but through the freezing chamber expansion valve  131  and the freezing chamber evaporator  140  only, a total flow distance (i.e., a circulating distance) is shortened. According to this, the torque required for initial starting of the compressor  110  is reduced in proportion to the shortened flow distance of the refrigerant. 
   Thereafter, when operation of the compressor  110  is stabilized, the regulating valve  170  is operated, to open a flow passage to the refrigerating chamber expansion valve  132 . 
   In this instance, if the torque of the compressor  110  shows no change, it may be considered that the compressor  110  is in a stable state. Moreover, only with no sudden increase of the torque of the compressor  110 , the stable state of the compressor  110  can be identified. On the other hand, if a preset time period passes after putting the compressor  110  into operation, it may be considered that operation of the compressor  110  is reached to the stable state. 
   At the end, as the refrigerant flow to the refrigerating chamber evaporator  150  is performed according to the foregoing series of steps, to make heat exchange at the freezing chamber evaporator  140  and the refrigerating chamber evaporator  150  at the same time, stable supply of cold air to the freezing chamber and the refrigerating chamber is made. 
   Alternatively, instead of supplying refrigerant to the refrigerating chamber evaporator  150  only when the operation of the compressor  110  is stabilized, the refrigerant supply to the refrigerant chamber evaporator  150  may be increased gradually, to prevent momentary torque increase of the compressor  110  caused by sudden refrigerant flow path change from occurring. For such a refrigerant supply control, the regulating valve  170  is not a general valve that only opens/closes a flow passage simply, but a valve that can adjust a degree of opening of the flow passage. 
   In this case, at initial operation of the refrigerating system, i.e., at initial operation of the compressor  110 , refrigerant supply to the refrigerating chamber evaporator  150  is cut off completely, and is increased, gradually. Finally, when the refrigerating system, i.e., the compressor  110 , reaches to a stable state, refrigerant is supplied to the refrigerating chamber evaporator  150  fully. In more detail, at the time of initial starting of the compressor  110 , the regulating valve  170  closes the refrigerant pipe  160  completely, and then, the regulating valve  170  increases the degree of opening of the refrigerant pipe gradually in a predetermined time period. If the operation of the compressor  110  reaches to a stable state fully, the regulating valve  170  opens the refrigerant pipe  160 , fully. 
   As has been described, by regulating refrigerant supply to the refrigerating chamber evaporator, the refrigerating system of the present invention can reduce a torque required for initial operation of the compressor. Accordingly, the use of a compressor requiring a relatively low torque permits to reduce a production cost of the refrigerating system, and increase efficiency of the refrigerating system owing to a low power consumption. 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.