Cooling device

Abstract

The present invention provides precise temperature control of a cooling chamber and comprises: a cooling chamber; a refrigeration circuit having a compressor, a condenser installed at the outlet side of the compressor, an evaporator, installed between the outlet side of the condenser and the inlet side of the compressor, for cooling the cooling chamber, and a decompression means installed at the inlet side of the evaporator; and a refrigerant control unit which has a refrigerant control valve installed between the condenser and the evaporator, and which adjusts the refrigerant flow rate that flows into the evaporator by controlling the opening/closing time of the refrigerant control valve.

Claims

1. A cooling device comprising: a cooling chamber; a refrigeration circuit that includes a compressor, a condenser installed at an outlet side of the compressor, an evaporator installed between an outlet side of the condenser and an inlet side of the compressor to cool the cooling chamber, and a capillary tube installed at an inlet side of the evaporator; and a refrigerant control unit that includes a refrigerant control valve installed between the condenser and the evaporator and is configured to control a fully opening and closing time of the refrigerant control valve and to sequentially change a refrigerant flow rate that flows to the evaporator and another evaporator.

2. The cooling device of claim 1, wherein the refrigerant control unit is further configured to perform a duty control on the refrigerant control valve.

3. The cooling device of claim 2, wherein a cycle of the duty control is set from 3 to 200 seconds.

4. The cooling device of claim 2, wherein an ON time of the refrigerant control valve is set to be longer than an OFF time thereof in the duty control.

5. The cooling device of claim 2, wherein the refrigerant control unit is further configured to set a duty ratio so that a difference between an inlet temperature and an outlet temperature of the evaporator is uniform in the duty control.

6. The cooling device of claim 1, wherein an OFF time is set to be longer than an ON time during a refrigerant control valve operation.

7. The cooling device of claim 1, wherein the refrigerant control unit is further configured to perform variable controls on a time ratio of an ON time of the refrigerant control valve to an OFF time thereof depending on an ambient temperature.

8. The cooling device of claim 1, wherein a check valve is installed between the evaporator and the compressor to prevent refrigerant from back-flowing.

9. The cooling device of claim 1, wherein the refrigerant control valve is configured to repeat an opening and closing routine, in which a plurality of opening and closing selective modes having a combination of an opening valve state in which refrigerant flows to each of a plurality of evaporators and a closing valve state in which the refrigerant does not flow thereto are sequentially switched between several times during one stroke of a valve body.

10. A cooling device comprising: a plurality of cooling chambers having temperatures different from each other; a refrigeration circuit that includes a compressor, a condenser installed at an outlet side of the compressor, a plurality of evaporators connected in parallel between an outlet side of the condenser and an inlet side of the compressor and respectively installed to correspond to the plurality of cooling chambers, and a plurality of capillary tubes respectively installed at inlet sides of the evaporators; and a refrigerant control unit that includes a refrigerant control valve which is installed between the condenser and the plurality of evaporators and configured to: control a refrigerant flow rate that flows into each of the evaporators and individually controls a ratio of refrigerants that flow to the respective evaporators by controlling a fully opening and closing time of the refrigerant control valve during a simultaneous cooling operation of simultaneously cooling the plurality of cooling chambers; and sequentially change the refrigerant flow rate that flows into the evaporators.

11. The cooling device of claim 10, wherein the refrigerant control unit is further configured to alternately perform a refrigerant full outflow period in which the refrigerant flows to all of the plurality of evaporators and a refrigerant partial outflow period in which the refrigerant flows to some of the plurality of evaporators by controlling the fully opening and closing time of the refrigerant control valve.

12. The cooling device of claim 10, wherein the refrigerant control unit is further configured to perform a duty control on the refrigerant control valve.

13. The cooling device of claim 10, wherein the refrigerant control valve is further configured to repeat an opening and closing routine, in which a plurality of opening and closing selective modes having a combination of an opened valve state in which the refrigerant flows to each of the plurality of evaporators and a closed valve state in which the refrigerant does not flow thereto are sequentially switched between several times during one stroke of a valve body.

14. A cooling device comprising: a plurality of cooling chambers having temperatures different from each other; a refrigerant circuit that includes a compressor, a condenser installed at an outlet side of the compressor, a plurality of evaporators connected in parallel between an outlet side of the condenser and an inlet side of the compressor and respectively installed to correspond to the plurality of cooling chambers, and a plurality of capillary tubes respectively installed at inlet sides of the evaporators; and a refrigerant control unit that includes a refrigerant control valve installed between the condenser and the plurality of evaporators to selectively switch an evaporator supplying a refrigerant among the plurality of evaporators and to sequentially change the refrigerant flow rate that flows into the plurality of evaporators, wherein the refrigerant control unit is configured to control a refrigerant flow rate that flows into the evaporator supplying the refrigerant after switching to the evaporator by controlling an opening and closing time of the refrigerant control valve.

15. A cooling device comprising: a plurality of cooling chambers having temperatures different from each other; a refrigerant circuit that includes a compressor, a condenser installed at an outlet side of the compressor, a plurality of evaporators connected in parallel between an outlet side of the condenser and an inlet side of the compressor and respectively installed to correspond to the plurality of cooling chambers, and a plurality of capillary tubes respectively installed at inlet sides of the evaporators; a refrigerant control unit including a refrigerant control valve installed between the condenser and the plurality of evaporators to selectively switch an evaporator supplying a refrigerant among the plurality of evaporators and to sequentially change the refrigerant flow rate that flows into the plurality of evaporators; and a defroster configured to remove frost from any one of the plurality of evaporators, wherein the refrigerant control unit is configured to control a refrigerant flow rate that flows to an evaporator from which the frost is not removed when frost is removed from any one of the plurality of evaporators by the defroster by controlling an opening and closing time of the refrigerant control valve.

16. A cooling device comprising: a plurality of cooling chambers having temperatures different from each other; a refrigerant circuit that includes a compressor, a condenser installed at an outlet side of the compressor, a plurality of evaporators connected in parallel between an outlet side of the condenser and an inlet side of the compressor and respectively installed to correspond to the plurality of cooling chambers, and a plurality of capillary tubes respectively installed at inlet sides of the evaporators; and a refrigerant control unit that includes a refrigerant control valve installed between the condenser and the plurality of evaporators to control a refrigerant flow rate that flows into each of the evaporators and sequentially changes the refrigerant flow rate that flows into the plurality of evaporators.

17. The cooling device of claim 16, wherein the refrigerant control unit is further configured to change the refrigerant flow rate that flows to each of the evaporators at change rates different from each other.

18. The cooling device of claim 16, wherein the refrigerant control valve includes a valve main body having an input port connected to the outlet side of the condenser and a plurality of output ports respectively connected to the inlet sides of the plurality of evaporators, and a valve body installed to correspond to each of the plurality of the output ports in the valve main body and opening and closing outlets connected to the output ports, wherein a total of opening degrees of the outlets in the plurality of output ports is less than 100%.

19. The cooling device of claim 18, wherein the valve body has a fully closed state in which the plurality of output ports are simultaneously closed.

20. The cooling device of claim 18, wherein the refrigerant control unit is further configured to sequentially change the opening degree of the outlets in the plurality of output ports depending on a change in a load of each of the cooling chambers.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic configuration diagram of a cooling device according to a first embodiment.

(2) FIG. 2 is a view illustrating a first operation pattern of a refrigerant control valve according to the first embodiment.

(3) FIG. 3 is a view illustrating a second operation pattern of the refrigerant control valve according to the first embodiment.

(4) FIG. 4 is a schematic configuration diagram of a cooling device according to a modification of the first embodiment.

(5) FIG. 5 is a schematic configuration diagram of a cooling device according to a modification of the first embodiment.

(6) FIG. 6 is a schematic configuration diagram of a cooling device according to a modification of the first embodiment.

(7) FIG. 7 is a schematic configuration diagram of a cooling device according to a second embodiment.

(8) FIG. 8 is a schematic view illustrating a configuration of a refrigerant control valve according to the second embodiment.

(9) FIG. 9 is a schematic view mainly illustrating a configuration of an outlet and a valve body of the refrigerant control valve according to the second embodiment.

(10) FIG. 10 is a view illustrating an operation pattern of the refrigerant control valve according to the second embodiment.

(11) FIG. 11 is a view illustrating a location of the valve body in each mode of the refrigerant control valve according to the second embodiment.

(12) FIG. 12 is a schematic view mainly illustrating a configuration of an outlet and a valve body of a refrigerant control valve according to a modification of the second embodiment.

(13) FIG. 13 is a view illustrating an operation pattern of the refrigerant control valve in the modification of the second embodiment.

(14) FIG. 14 is a view illustrating a location of the valve body in each mode of the refrigerant control valve in the modification of the second embodiment.

(15) FIG. 15 is a schematic configuration diagram of a cooling device according to a third embodiment.

(16) FIG. 16 is a schematic view illustrating a configuration of a refrigerant control valve of the third embodiment.

(17) FIG. 17 is a schematic view illustrating an inner configuration of the refrigerant control valve of the third embodiment.

(18) FIG. 18 is a view illustrating an operation pattern of the refrigerant control valve of the third embodiment.

(19) FIG. 19 is a view illustrating a change in an opening degree by the refrigerant control valve of the third embodiment.

(20) FIG. 20 is a view illustrating a temperature distribution according to the third embodiment.

(21) FIG. 21 is a view illustrating a change in an opening degree by a refrigerant control valve in a modification of the third embodiment.

(22) FIG. 22 is a view illustrating a temperature distribution according to the modification of the third embodiment.

(23) FIG. 23 is a view illustrating a change in the opening degree according to the refrigerator control valve in the modification of the third embodiment.

(24) FIG. 24 is a view illustrating a method of minutely adjusting a refrigerant flow rate according to the modification of the third embodiment.

(25) FIG. 25 is a schematic configuration diagram of a cooling device according to a fourth embodiment.

(26) FIG. 26 is a view illustrating an opening operation pattern of a refrigerant control valve according to the fourth embodiment.

(27) FIG. 27 is a schematic configuration view of a cooling device according to a modification of the fourth embodiment.

(28) FIG. 28 is a view illustrating an opening operation pattern of a refrigerant control valve according to the modification of the fourth embodiment.

(29) FIG. 29 is a view illustrating an operation pattern of a conventional refrigerant control valve.

MODES OF THE INVENTION

First Embodiment

(30) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

(31) A cooling device 100 according to the first embodiment, as shown in FIG. 1, is a refrigerator including a refrigerated compartment 11 and a freezer compartment 12, and includes a refrigeration circuit 200 including a compressor 21, a condenser 22 installed at an outlet side of the compressor 21, a refrigerated compartment evaporator 23A and a freezer compartment evaporator 23B installed between the outlet side of the condenser 22 and an inlet side of the compressor 21 and connected with each other in parallel, and a refrigerated compartment decompression means 24A, for example a capillary tube, installed in series at an inlet side of the refrigerated compartment evaporator 23A and a freezer compartment decompression means 24B, for example a capillary tube, installed in series at an inlet side of the freezer compartment evaporator 23B.

(32) In this case, the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B are respectively installed in two refrigerant branching passages 201 and 202 branched from the outlet side of the condenser 22. The refrigerated compartment evaporator 23A is installed to cool the inside of the refrigerated compartment 11, and the freezer compartment evaporator 23B is installed to cool the inside of the freezer compartment 12.

(33) The cooling device 100 of the embodiment, as shown in FIG. 1, includes a refrigerant control unit 3 individually controlling a refrigerant flow rate flowing to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B by adjusting the refrigerant flow rate that flows into each of the refrigerant branching passages 201 and 202.

(34) The refrigerant control unit 3 includes a refrigerant control valve 31 that controls the refrigerant flow rate that flows into the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a control device 32 that controls the corresponding refrigerant control valve 31. The control device 32 is a general or exclusive computer including a central processing unit (CPU), a memory, an input output interface, an analog to digital (AD) converter and the like, and controls the refrigerant control valve 31 by enabling the CPU, peripherals and the like to cooperate with each other according to a control program stored in a predetermined area of the memory.

(35) The refrigerant control valve 31 of the embodiment is a 3-way valve installed at a branching point of the refrigerant branching passages 201 and 202. An input port is connected with a refrigerant tube on a side of the condenser 22, a first output port is connected with a branching tube configuring the refrigerant branching passage 201 on the refrigerated compartment evaporator 23A, and a second output port is connected with a branching tube configuring the refrigerant branching passage 202 on the freezer compartment evaporator 23B. The refrigerant control valve 31 individually controls an opening degree of the first output port and the second output port using a control signal from the control device 32.

(36) Hereinafter, an embodiment of an operation pattern of the refrigerant control valve 31 by the control device 32 will be described with reference to FIGS. 2 and 3.

(37) The control device 32 individually adjusts the refrigerant flow rate that flows into the refrigerated compartment evaporator 23A and the refrigerant flow rate that flows into the freezer compartment evaporator 23B by controlling an opening and closing time of the refrigerant control valve 31 depending on loads of the refrigerated compartment 11 and the freezer compartment 12 or a change in the loads in a simultaneous cooling operation of simultaneously cooling the refrigerated compartment 11 and the freezer compartment 12, thereby adjusting a division ratio of the refrigerants flowing in the respective evaporators.

(38) Specifically, the control device 32 obtains a detected temperature from a temperature sensor 4A installed inside the refrigerated compartment 11 to detect an internal temperature of the refrigerated compartment 11, a detected temperature of the freezer compartment 12 from a temperature sensor 4B installed inside the freezer compartment 12 to detect an internal temperature of the freezer compartment 12, and a detected temperature from an external air temperature sensor 5 installed outside the cooling device 100 to detect an external air temperature.

(39) Also, the control device 32 calculates a load of the refrigerated compartment 11 or a change in the load from the internal temperature of the refrigerator and the external air temperature and simultaneously calculates a load of the freezer compartment 12 or a change in the load from the internal temperature of the refrigerator and the external air temperature, and calculates a time ratio of a fully opened time of the first output port and the second output port of the refrigerant control valve to a fully closed time thereof from the calculated result. The control device 32 outputs a control signal obtained by the calculation to the refrigerant control valve 31 to control the refrigerant control valve 31.

(40) In this case, a switching cycle of the fully opened time and the fully closed time varies from 3 to 200 seconds, and the time ratio of the fully opened time to the fully closed time varies between corresponding switching cycles.

(41) For example, when the fully opened time is referred to as TON and the fully closed time is referred to as TOFF, the period of TON+TOFF may be from 3 to 200 seconds. Also, the time ratio of the fully opened time to the fully closed time is determined by, for example, being appropriately varied based on detected signals from the temperature sensor 4A in the refrigerated compartment 11 and the temperature sensor 4B in the freezer compartment 12.

(42) The control device 32, as shown in FIG. 2, alternately performs a full refrigerant outflow period in which the refrigerant flows to both of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a partial refrigerant outflow period in which the refrigerant flows only to the refrigerated compartment evaporator 23A by controlling an opening and closing time of the first port and the second port of the refrigerant control valve 31. In this case, when the first port is fully opened all the time, the refrigerant flows to the refrigerated compartment evaporator 23A, and the time ratio of the fully opened time of the second port to the fully closed time thereof is controlled, thereby enabling the refrigerant to intermittently flow to the freezer compartment evaporator 23B.

(43) Also, the control device 32, as shown in FIG. 3, may allow the refrigerant to sequentially flow to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B by controlling the opening and closing time of the first port and the second port of the refrigerant control valve 31. In this case, the control device 32 controls the time ratio of the fully opened time of the first port and the second port to the fully closed time thereof to enable the refrigerant to intermittently flow to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and enable a timing at which the refrigerant flows to the refrigerated compartment evaporator 23A and a timing at which the refrigerant flows to the freezer compartment evaporator 23B to be opposites of each other. Also, the operation pattern may be performed only when a uni-directional flow of the refrigerant is generated by the operation pattern shown in FIG. 2.

Effect of First Embodiment

(44) According to the cooling device 100 configured as above, since the simultaneous cooling operation for simultaneously cooling the refrigerated compartment 11 and the freezer compartment 12 is performed, all evaporators perform the cooling operation, and thus it is difficult for the refrigerant to gather in the corresponding evaporators 23A and 23B. Also, since the opening and closing time of the refrigerant control valve 31 is controlled depending on the loads of the refrigerated compartment 11 and the freezer compartment 12 or a change in the loads when the simultaneous cooling operation is performed, the refrigerant flow rate may be responsively controlled depending on the loads or the change in the loads, and the temperatures of the refrigerated compartment 11 and the freezer compartment 12 may be precisely controlled with an excellent response, thereby impeding the spoiling of foods stored in the refrigerated compartment 11 and the freezer compartment 12 and also reducing power consumption when overheating of the evaporators 23A and 23B is controlled. In addition, when the opening degree of a valve is controlled in the cooling device with a low refrigerant flow rate, it is difficult to control the opening degree of the valve, and thus, in the embedment, the opening and closing time of the refrigerant control valve 31 is controlled to easily and precisely control the refrigerant flow rate.

Modification of the First Embodiment

(45) Also, the present invention is not limited to the first embodiment. For example, in the first embodiment, the cooling device 100 having the refrigerated compartment 11 and the freezer compartment 12 was described but, as shown in FIG. 4, the cooling device 100 may include three evaporators 23A to 23C installed to correspond to three or more cooling chambers (three cooling chambers in FIG. 4) with different cooling temperatures. In this case, a 4-way valve 31 may be installed as a refrigerant control valve at a branching point of refrigerant branching passages 201 to 203 that are branched into three passages to control a refrigerant flow rate of each of the refrigerant branching passages 201 to 203. Also, 24A to 24C are a decompression means installed upstream of the evaporators.

(46) Also, in the first embodiment, the 3-way valve 31 may be installed at the branching point of the three refrigerant branching passages 201 and 202 as the refrigerant control valve but, as shown in FIG. 5, two 2-way valves 31A and 31B may be respectively installed upstream of the decompression means 24A and 24B at the refrigerant branching passages 201 and 202. Even in this case, a time ratio of opening and closing times of the two 2-way valves 31 varies from 3 to 200 seconds.

(47) As shown in FIG. 6, a check valve 6 that prevents the refrigerant from back-flowing may be installed on an outlet side of the freezer compartment evaporator 23B.

Second Embodiment

(48) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

(49) A cooling device 100 according to the second embodiment, as shown in FIG. 7, includes a refrigerated compartment 11, a freezer compartment 12, and a refrigeration circuit 200 including a compressor 21, a condenser 22 installed at an outlet side of the corresponding compressor 21, a refrigerated compartment evaporator 23A and a freezer compartment evaporator 23B installed between the outlet side of the corresponding condenser 22 and an inlet side of the compressor 21 and connected with each other in parallel, and a refrigerated compartment decompression means 24A, for example a capillary tube, installed in series at an inlet side of the refrigerated compartment evaporator 23A and a freezer compartment decompression means 24B, for example a capillary tube, installed in series at an inlet side of the freezer compartment evaporator 23B.

(50) In this case, the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B are respectively installed at two refrigerant branching passages 201 and 202 branched from the outlet side of the condenser 22. The refrigerated compartment evaporator 23A is installed to cool the inside of the refrigerated compartment 11, and the freezer compartment evaporator 23B is installed to cool the inside of the freezer compartment 12. Also, a check valve 6 that prevents the refrigerant from back-flowing is installed at an outlet side of the freezer compartment evaporator 23B.

(51) The cooling device 100 of the embodiment, as shown in FIG. 7, includes a refrigerant control unit 3 individually controlling the refrigerant flow rate that flows into the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B by adjusting the refrigerant flow rate that flows into each of the refrigerant branching passages 201 and 202.

(52) The refrigerant control unit 3 includes a refrigerant control valve 31 that controls the refrigerant flow rate that flows into the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a control device 32 that controls the corresponding refrigerant control valve 31.

(53) The refrigerant control valve 31 of the embodiment, as shown in FIG. 8, is a 3-way valve installed at a branching point of the refrigerant branching passages 201 and 202. An input port P1 is connected with a refrigerant tube on a side of the condenser 22, a first output port P2 is connected with a branching tube configuring the refrigerant branching passage 201 on the refrigerated compartment evaporator 23A, and a second output port P3 is connected with a branching tube configuring the refrigerant branching passage 202 on a side of the freezer compartment evaporator 23B.

(54) Specifically, the refrigerant control valve 31, as shown in FIGS. 8 and 9, includes a valve main body 311 including the input port P1, the first output port P2, and the second output port P3 and having an inner space S which allows the inlet and output ports to be in communication with each other, and a valve body 312 installed in the inner space S of the valve main body 311 and including a plurality of communication holes H1 and H2 allowing the input port P1 and the two output ports P2 and P3 to be fully or partially in communication with each other. Also, numeral reference P1a refers to an inlet connected with the input port P1.

(55) In the refrigerant control valve 31 of the embodiment, an outlet-formed surface (a valve seat, 311x) on which outlets P2a and P3a of the two output ports P2 and P3 are formed is flat. The valve body 312 slidably rotates around a predetermined rotating shaft on an outlet-formed surface 311x to open and close each of the outlets P2a and P3a. The rotating shaft of the valve body 312 is a shaft installed to be equidistant from the two outlets P2a and P3a, and more specifically, is a center point of the two outlets P2a and P3a.

(56) The valve body 312 has a disk shape and has the plurality of communication holes H1 and H2 formed in a circumferential direction with respect to the rotating shaft. In the embodiment, a plurality of first communication holes H1 (5 holes in FIG. 9) corresponding to the outlet P2a of the first output port P2 and a plurality of second communication holes H2 (4 holes in FIG. 9) corresponding to the outlet P3a of the second output port P3 are formed. The valve body 312 rotates about the rotating shaft so that the first communication hole H1 corresponding to the outlets P2a and the corresponding outlet P2a overlap with each other or the second communication hole H2 corresponding to the outlet P3a and the corresponding outlet P3a overlap with each other, and thus the input port P1 is in communication with the first output port P2 and/or the second output port P3.

(57) Therefore, a combination of a valve opening state in which the refrigerant flows to each of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a valve closing state in which the refrigerant does not flow is determined, and a plurality of opening and closing states different from each other (opening and closing selection modes) are determined. That is, in the embodiment,

(58) (1) a fully closed mode (closed-closed mode) in which the refrigerant does not flow to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B,

(59) (2) a refrigerated compartment-selecting mode (opened-closed mode) in which the refrigerant flows to the refrigerated compartment evaporator 23A but does not flow to the freezer compartment evaporator 23B,

(60) (3) a freezer compartment-selecting mode (closed-opened mode) in which the refrigerant does not flow to the refrigerated compartment evaporator 23A but flows to the freezer compartment evaporator 23B, and

(61) (4) a fully opened mode (opened-opened mode) in which the refrigerant flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B.

(62) Further, in the embodiment, the plurality of communication holes H1 corresponding to the outlet P2a of the first output port P2 and the plurality of communication holes H2 corresponding to the outlet P3a of the second output port P3 are formed at the valve body 312 so that the refrigerated compartment-selecting mode (opened-closed mode) and the freezer compartment-selecting mode (closed-opened mode) are alternately switched many times as the valve body 312 rotates during one stroke. That is, the plurality of communication holes H1 and the plurality of communication holes H2 are formed at the valve body 312 as if an opening and closing routine of sequentially switching between the refrigerated compartment-selecting mode (opened-closed mode) to the freezer compartment-selecting mode (closed-opened mode) is repeated as the valve body 312 rotates during one stroke.

(63) Also, the refrigerant control valve 31 includes a gear engaged with a gear part (not shown) formed on the valve body 312 and an actuator, such as a step motor and the like, rotating the corresponding gear 313, and the valve body 312 is rotated by the corresponding actuator through the gear. Also, the actuator is able to rotate the valve body 312 forward or backward. That is, each valve body 312 is reciprocated in a predetermined rotation range by the gear.

(64) Further, as the actuator is controlled by the control signal from the control device 32, the valve body 312 rotates, and the refrigerant control valve 31 switches the opening and closing modes of the outlets P2a and P3a of the two output ports P2 and P3.

(65) The control device 32 is a general or exclusive computer including a CPU, a memory, an input output interface, an AD converter and the like, and controls the refrigerant control valve 31 by enabling the CPU, peripheral devices and the like to cooperate with each other according to a control program stored in a predetermined area of the memory.

(66) Specifically, the control device 32 obtains a detected temperature from a temperature sensor 4A installed in the refrigerated compartment 11 to detect an internal temperature of the corresponding refrigerated compartment 11, a detected temperature from a temperature sensor 4B installed in the freezer compartment 12 to detect an internal temperature of the corresponding freezer compartment 12, and a detected temperature form an external air temperature sensor 5 installed outside the cooling device 100 to detect an external air temperature.

(67) Also, the control device 32 calculates a load of the refrigerated compartment 11 or a change in the load from the internal temperature of the refrigerator and the external air temperature and simultaneously calculates a load of the freezer compartment 12 or a change in the load from the internal temperature of the refrigerator and the external air temperature, and determines the opening and closing modes of the outlet P2a of the first output port P2 and the outlet P3a of the second output port P3 of the refrigerant control valve 31 based on the calculation result. The control device 32 controls the refrigerant control valve 31 by outputting a control signal obtained through the above mentioned calculation to the refrigerant control valve 31.

(68) A control state of a refrigerant flow rate in the refrigerant control unit 3 of the embodiment will be described with reference to FIGS. 10 and 11.

(69) The refrigerant control valve 31 of the embodiment, as shown in FIGS. 10 and 11, switches from the fully closed mode (closed-closed mode: mode A) in which the refrigerant does not flow to both the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B to the refrigerated compartment selecting mode (opened-closed mode: mode B) when the valve body 312 rotates. Then, when the valve body 312 rotates further, the refrigerated compartment selecting mode is switched into the freezer compartment selecting mode (closed-opened mode: mode D). As the valve body 312 rotates during one stroke, the mode B and the mode D are alternately switched between each other, and an opening and closing routine is repeated many times (see FIG. 10). That is, as the valve body 312 rotates, communication between the first communication hole H1 and the outlet P2a and communication between the second communication hole H2 and the outlet P3a are alternately switched between each other (see FIG. 11). Then, when the valve body 312 rotates further, the mode is switched to the fully opened mode (opened-opened mode: mode C) in which the refrigerant flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B. The state from the mode A to the mode C is a portion of a half of the stroke. The valve body 312, as mentioned above, rotates backward for the portion of the rest of the stroke while the mode B and the mode C are alternately switched between each other, that is, the opening and closing routine is repeated several times. Like this, one stroke of the valve body 312 of the embodiment refers to one operation in which the valve body 312 rotates forward from an initial position in a predetermined angle range, for example, an angle of 180 degrees or less but approximately an angle of 100 degrees in the embodiment, and then rotates backward to the initial position. Also, the valve body 312 rotates forward or backward without passing through the mode A and mode C to extend the number (the number of opening and closing routines) of switching from the mode B to the mode D.

Effect of Second Embodiment

(70) According to the cooling device 100 configured as above, since the refrigerant control valve 31 has the same several opening and closing routines from the refrigerated compartment selecting mode and the freezer compartment selecting mode during an one stroke operation of the valve body 312 and switches between the refrigerated compartment selecting mode and the freezer compartment selecting mode several times during one stroke to reciprocate in the same place, the number of repeated operations is reduced, thereby increasing the durability of the refrigerant control valve 31. Also, the same several opening and closing routines are provided during an one stroke operation of the valve body 312 so that each movement distance between the opening and closing selecting modes may be reduced and the movement time may be reduced, and thus the temperatures of the refrigerated compartment 11 and the freezer compartment 12 are precisely controlled. Particularly, in the embodiment, since the opening and closing routine is repeated several times from the refrigerated compartment selecting mode and the freezer compartment selecting mode as the valve body 312 rotates during one stroke, the switching between the refrigerated compartment selecting mode and the freezer compartment selecting mode of the valve body 312 can be performed with small movement, and the movement time of the valve body 312 may be further reduced, and thus the temperatures of the refrigerated compartment 11 and the freezer compartment 12 can be precisely controlled.

Modification of Second Embodiment

(71) The present invention is not limited to the second embodiment.

(72) For example, in the second embodiment, the refrigerant control valve 31 switches a mode between the refrigerated compartment selecting mode and the freezer compartment selecting mode, but the refrigerant control valve 31 may have a one-side selecting mode in which the refrigerant flows to one of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a both-side selecting mode in which the refrigerant flows to both of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and may have several opening and closing routines from the one-side selecting mode and the both-side selecting mode during an one stroke operation of the valve body 312. Specifically, as shown in FIG. 12, the valve body 312 has a half disk shape and has a plurality of communication holes H2 in a circumferential direction around a rotating shaft. In detail, the valve body 312 has a plurality of second communication holes H2 (four holes in FIG. 12) corresponding to the outlet P3a of the second output port P3. As the valve body 312 rotates around the rotating shaft, the second communication holes H2 corresponding to the outlet P3a overlap with the corresponding outlet P3a, and the input port P1 and the second output port P3 come into communication with each other. Also, the outlet P2a is opened all the time except for in the mode A of FIG. 13 and is in communication with the input port P1 and the first output port P2 all the time.

(73) Therefore, the combination of an opened valve state in which the refrigerant flows to each of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a closed valve state in which the refrigerant does not flow is determined, and a plurality of opening and closing states different from each other (opening and closing selection modes) are determined. That is, in the embodiment,

(74) (1) a fully closed mode (closed-closed mode) in which the refrigerant does not flow to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B,

(75) (2) a refrigerated compartment selecting mode (opened-closed mode) that is the one-side selecting mode in which the refrigerant flows to the refrigerated compartment evaporator 23A but does not flow to the freezer compartment evaporator 23B, and

(76) (3) a fully opened mode (opened-opened mode) that is the both-side selecting mode in which the refrigerant flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B is determined.

(77) Next, in the refrigerant control valve 31, as shown in FIGS. 13 and 14, when the valve body 312 rotates in the fully closed mode (closed-closed mode: mode A) in which the refrigerant does not flow to both of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B, the mode A is switched into the refrigerated compartment selecting mode (opened-closed mode: mode B). Then, when the valve body 312 rotates further in the refrigerated compartment selecting mode, the mode B is switched into the fully opened mode (opened-opened mode: mode C). As the valve body 312 rotates during one stroke, the mode B and the mode C are alternatively switched, and the opening and closing routine is repeated several times (see FIG. 13). That is, as the valve body 312 rotates, communication and blocking between the second communication hole H2 and the outlet P3a are alternately switched while the first communication hole H1 and the outlet P2a are in communication with each other all the time (see FIG. 14). Next, the valve body 312 rotates backward to alternately switch between the mode B and the mode C, and the opening and closing routine is repeated several times. In this case, the time ratio of the refrigerated compartment selecting mode (mode B) to the fully opened mode (mode C) in the refrigerant control valve 31 is controlled, and thus the ratio of the refrigerant flow rate of the refrigerated compartment evaporator 23A to the refrigerant flow rate of the freezer compartment evaporator 23B may be adjusted.

(78) Also, the refrigerant control valve 31 has been a pad type slide valve having the valve body 312 with a disk shape, a half-disk shape or the like, but may be a slide valve having a valve body having other shapes or may be, for example, a spool valve having a plurality of inner passages in which the inlet P1a of the input port P1 and the outlets P2a and P3a of the output port P2 and P3 may individually come into communication.

Third Embodiment

(79) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

(80) A cooling device 100 according to the third embodiment, as shown in FIG. 15, includes a refrigerated compartment 11, a freezer compartment 12, and a refrigeration circuit 200 including a compressor 21, a condenser 22 installed at an outlet side of the corresponding compressor 21, a refrigerated compartment evaporator 23A and a freezer compartment evaporator 23B installed between the outlet side of the corresponding condenser 22 and an inlet side of the compressor 21 and connected with each other in parallel, and a refrigerated compartment decompression means 24A, for example a capillary tube, installed in series at an inlet side of the refrigerated compartment evaporator 23A and a refrigerated compartment decompression means 24B, for example a capillary tube, installed in series at an inlet side of the freezer compartment evaporator 23B.

(81) In this case, the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B are installed in two refrigerant branching passages 201 and 202 branched from the outlet side of the condenser 22, respectively. The refrigerated compartment evaporator 23A is installed to cool the inside of the refrigerated compartment 11, and the freezer compartment evaporator 23B is installed to cool the inside of the freezer compartment 12. Also, a check valve 6 that prevents a refrigerant from back-flowing is installed on the outlet side of the freezer compartment evaporator 23B.

(82) The cooling device 100 of the embodiment, as shown in FIG. 15, includes a refrigerant control unit 3 that controls a refrigerant flow rate that flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B by continuously and simultaneously changing a refrigerant flow rate by adjusting a refrigerant flow rate that flows into each of the refrigerant branching passages 201 and 202.

(83) The refrigerant control unit 3 includes a refrigerant control valve 31 that controls the refrigerant flow rate that flows into the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a control device 32 that controls the corresponding refrigerant control valve 31.

(84) The refrigerant control valve 31 of the embodiment, as shown in FIG. 16, is a 3-way valve installed at a branching point of the refrigerant branching passages 201 and 202. An input port P1 is connected with a refrigerant tube on the condenser 22, a first output port P2 is connected with a branching tube configuring the refrigerant branching passage 201 on the refrigerated compartment evaporator 23A, and a second output port P3 is connected with a branching tube configuring the refrigerant branching passage 202 on the freezer compartment evaporator 23B.

(85) Specifically, the refrigerant control valve 31, as shown in FIGS. 16 and 17, includes a valve main body 311 including the input port P1, the first output port P2, and the second output port P3 and having an inner space S allowing the inlet and output ports to be in communication with each other, and two valve bodies 312a and 312b installed in the inner space S of the valve main body 311 to respectively correspond to the two output ports P2 and P3, and opening and closing the outlets P2a and P3a connected with the outlets P2 and P3. Also, the numeral reference P1a refers to an inlet connected with the input port P1.

(86) In the refrigerant control valve 31 of the embodiment, an outlet-formed surface 311x on which the outlets P2a and P3a of the two output ports P2 and P3 are formed is flat. Each of the two valve bodies 312a and 312b slidably rotates about each predetermined rotating shaft on the outlet-formed surface 311x to open and close each of the outlets P2a and P3a.

(87) In each of the valve bodies 312a and 312b, the shape of an outline of a part through which the outlets P2a and P3a pass has a curved shape convex toward a rotation direction. Also, the shape of the outline is the shape of a slide surface sliding on the outlet-formed surface 311x when viewed from the rotation direction of the valve bodies 312a and 312b.

(88) In the embodiment, a shape of an outline in the valve body 312a has a curved shape convex toward the rotation direction when the corresponding valve body 312a rotates toward a direction of blocking the outlet P2a. A shape of an outline in the valve body 312b has a curved shape convex toward the rotation direction when the corresponding valve body 312b rotates toward a direction of blocking the outlet P3a. Also, the shapes of the outlines in the valve bodies 312a and 312b are an involute curve and have the same shape.

(89) Also, the refrigerant control valve 31 includes a gear 313 engaged with gear parts 312a1 and 312b1 each formed on the valve bodies 312a and 312b and an actuator (not shown), such as a step motor and the like, rotating the corresponding gear 313, and the two valve bodies 312a and 312b are rotated together by the corresponding actuator through the gear 313. Also, the actuator is able to rotate the valve bodies 312a and 312b forward or backward. That is, each of the valve bodies 312a and 312b is reciprocated in a predetermined rotation range by the gear 313.

(90) As the actuator is controlled by a control signal from the control device 32, the valve bodies 312a and 312b rotate, and thus the control valve 31 controls an opening degree of the outlets P2a and P3a of the two output ports P2 and P3.

(91) The control device 32 is a general or exclusive computer including a CPU, a memory, an input output interface, an AD converter and the like, and controls the refrigerant control valve 31 by enabling the CPU, peripheral devices and the like to cooperate with each other according to a control program stored in a predetermined area of the memory.

(92) Specifically, the control device 32 obtains a detected temperature from a temperature sensor 4A installed in the refrigerated compartment 11 to detect an internal temperature of the corresponding refrigerated compartment 11, a detected temperature from a temperature sensor 4B installed in the freezer compartment 12 to detect an internal temperature of the corresponding freezer compartment 12, and a detected temperature from an external air temperature sensor 5 installed outside the cooling device 100 to detect an external air temperature.

(93) Also, the control device 32 calculates a load of the refrigerated compartment 11 or a change in the load from the internal temperature of refrigerator and the external air temperature and simultaneously calculates a load of the freezer compartment 12 or a change in the load from the internal temperature of refrigerator and the external air temperature, and calculates a ratio of an opening degree of the outlet P2a of the second output port P2 of the control valve 31 to an opening degree of the outlet P3a of the second output port P3 of the control valve 31 based on the calculation result. The control device 32 controls the refrigerant control valve 31 by outputting a control signal obtained through the above mentioned calculation to the refrigerant control valve 31.

(94) A control state of a refrigerant flow rate in the refrigerant control unit 3 of the embodiment will be described with reference to FIGS. 18 and 19.

(95) When each of the valve bodies 312a and 312b is within a range from an initial position to a position of a rotation range of 10% (an area A), the outlet P2a of the first output port P2 is fully opened (an opening degree is 100%) and the outlet P3a of the second output port P3 is fully closed (an opening degree is 0%), and thus a refrigerant flow rate ratio for the refrigerated compartment evaporator becomes 100%, and a refrigerant flow rate ratio for the freezer compartment evaporator becomes 0%. Also, the initial position in the embodiment refers to a predetermined position at which the outlet P2a of the first output port P2 is fully opened and the outlet P3a of the second output port P3 is fully closed.

(96) Also, within a rotation range from 90% to 100% (an area C), the outlet P2a of the first output port P2 is fully closed (the opening degree is 0%), and the outlet P3a of the second output port P3 is fully opened (the opening degree is 100%), and thus the refrigerant flow rate ratio for the refrigerated compartment evaporator becomes 0%, and the refrigerant flow rate ratio for the freezer compartment evaporator becomes 100%. Also, the rotation range of 100% in the embodiment refers to a predetermined position at which the outlet P2a of the first output port P2 is fully closed and the outlet P3a of the second output port P3 is fully opened when the valve bodies rotate from the initial position.

(97) Also, a rotation range from 10% to 90% (an area B) is a range in which both opening degrees of the outlet P2a of the first output port P2 and the outlet P3a of the second output port P3 are adjustable (an adjustable area). In the adjustable area, the opening degree of the outlet P2a of the first output port P2 decreases linearly from 100% to 0%, and the opening degree of the outlet P3a of the second output port P3 increases linearly from 0% to 100%. That is, an opening degree change rate of the outlet P2a of the first output port P2 is regular, and an opening degree change rate of the outlet P3a of the second output port P3 is also regular. Also, the opening degree change rate of the outlet P2a and the opening degree change rate of the outlet P3a are opposite each other.

(98) When the control is performed, a change in the internal temperature of the refrigerated compartment 11 and an inlet temperature and an outlet temperature of the refrigerated compartment evaporator 23A and a change in the internal temperature of the freezer compartment 12 and an inlet temperature and an outlet temperature of the freezer compartment evaporator 23B are shown in FIG. 20. As shown in FIG. 20, it is confirmed that when evaporation temperatures in the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B are continuously changed in the adjustable area, the internal temperatures of the refrigerated compartment 11 and the freezer compartment 12 are continuously adjusted.

Effect of Third Embodiment

(99) According to the cooling device configured as above, since the refrigerant control unit 3 continuously changes the refrigerant flow rate that flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B at the same time, a combination pattern of the flow rate ratios may be increased. Therefore, since the evaporation temperature in the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B may each be arbitrarily adjusted, the flow rate may be precisely controlled depending on the loads of the refrigerated compartment 11 and the freezer compartment 12, thereby increasing the cooling efficiency of the compressor 21 and reducing power consumption.

Modification of Third Embodiment

(100) The present invention is not limited to the third embodiment.

(101) For example, in the third embedment, the rotation range from 0% to 10% refers to the fully opened area (or the fully closed area), the rotation range from 10% to 90% refers to the adjustable area, and the rotation range from 90% to 100% refers to the fully closed area (or the fully opened area), but the rotation range is not limited thereto. The rotation range that refers to the adjustable area is not limited to the above range and may be arbitrarily set to, for example, the range from 20% to 80%. Also, besides the fully opened area, the adjustable area, and the fully closed area, a predetermined opening degree area may be included. Also, like this, the shape of the outline of a portion passing through the outlets P2a and P3a in the valve bodies 312a and 312b is set to a specific shape to be divided into each of the areas according to the rotation range.

(102) Also, the opening degree change rates of the outlets P2a and P3a of the output ports P2 and P3 in the adjustable area include a plurality of change rates. For example, as shown in FIG. 21, the adjustable area B may be divided into an area B1 with a low change rate, an area B2 with a high change rate, and an area B3 with a low change rate. In the FIG. 21, the change rates of the area B1 and the area B3 are the same. The opening degree change rate of the outlet P2a of the output port P2 and the opening degree change rate of the outlet P3a of the output port P3 are opposite each other. The change rates of the area B1 and the area B3 may be different from each other. At this time, in the valve bodies 312a and 312B, the shapes of the outlines of the portions passing through the outlets P2a and P3a have specific shapes, and thus the adjustable area may have a plurality of areas with different change rates.

(103) A change in the internal temperature of the refrigerated compartment 11 and the inlet temperature and the outlet temperature of the refrigerated compartment evaporator, and a change in the internal temperature of the freezer compartment 12 and the inlet temperature and the outlet temperature of the freezer compartment evaporator according to the refrigerant control unit 3 configured as above are shown in FIG. 22. As shown in FIG. 22, the evaporation temperatures in the refrigerated compartment evaporator and the freezer compartment evaporator in the adjustable area are continuously changed, and the internal temperatures of the refrigerated compartment 11 and the freezer compartment 12 may be continuously adjusted. Like this, the opening degree change rate of the outlets P2a and P3a are arbitrarily set, and the temperature may be more precisely controlled by the sequential change.

(104) Also, as shown in FIG. 23, the opening degree change rate of the outlet P2a of the first output port P2 and the opening degree change rate of the outlet P3a of the second output port P3 in the adjustable area are independently set. That is, the opening degree change rates may be set so that the sum of the opening degree of the outlet P2a and the opening degree of the outlet P3a does not become 100%. In this case, the shape of the outline of the portion that passes through each of the outlets P2a and P3a in the valve bodies have different shapes. In FIG. 23, the change rate of the outlet P3a of the second output port P3 is uniform, and the change rate of the outlet P2a of the first output port P2 has a plurality of change rates. Therefore, even when the refrigerant flow rate of each of the evaporators 23A and 23B is not equal to the opening rates of the outlets of the plurality of output ports by a temperature (a pressure) difference between the corresponding evaporators 23A and 23B, the refrigerant flow rate that flows to each of the evaporator 23A and 23B may be precisely controlled.

(105) Here, since the temperature (the pressure) of the evaporator is changed when the refrigerated compartment load is changed, the refrigerant flow rates may not be equal to each other even with the same opening degree. In this case, as shown in FIG. 24, the refrigerant may be minutely adjusted to an arbitrary refrigerant flow rate by rotating the valve body in the adjustable area (an adjustable area B3 in FIG. 24) to continuously change the opening degree of the outlets in the plurality of output ports. For example, during the operation in step D of FIG. 24, (In this case, the refrigerant flow rate ratio of an R side: 20% to an F side: 80%) when the refrigerant flow rate ratio becomes the R side: 25% to the F side: 75% by a change in the freezer compartment load, the step is changed to step E by rotating the valve body, and thus the refrigerant flow rate ratio may be returned to an initial refrigerant flow rate ratio (the R side: 20% and the F side: 80%). Even when the refrigerant flow rate is changed by a change in the refrigerated compartment load, the opening degrees of the outlets in the plurality of output ports are continuously changed by rotating the valve body, and thus the refrigerant flow rate ratio may be minutely controlled to the predetermined refrigerant flow rate ratio.

(106) Also, in the embodiment, the shapes of outlines of the portions that pass through the outlets P2a and P3a in each valve body 312 have a curved shape, but the shapes are not limited thereto. The shape may be straight or curved, or a combination shape thereof.

Fourth Embodiment

(107) The fourth embodiment of the present invention will be described with reference to the drawings.

(108) A cooling device 100 according to the fourth embodiment, as shown in FIG. 25, includes a refrigerated compartment 11, a freezer compartment 12, and a refrigeration circuit 200 including a compressor 21, a condenser 22 installed at an outlet side of the corresponding compressor 21, a refrigerated compartment evaporator 23A and a freezer compartment evaporator 23B installed between the outlet side of the corresponding condenser 22 and an inlet side of the compressor 21 and connected with each other in parallel, and a refrigerated compartment decompression means 24A, for example a capillary tube, installed in series at an inlet side of the refrigerated compartment evaporator 23A and a refrigerated compartment decompression means 24B, for example a capillary tube, installed in series at an inlet side of the freezer compartment evaporator 23B.

(109) In this case, the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B are installed in two refrigerant branching passages 201 and 202 branched from the outlet side of the condenser 22, respectively. The refrigerated compartment evaporator 23A is installed to cool the inside of the refrigerated compartment 11, and the freezer compartment evaporator 23B is installed to cool the inside of the freezer compartment 12.

(110) The cooling device 100 of the embodiment, as shown in FIG. 25, includes a refrigerant control unit 3 that individually controls the refrigerant flow rate that flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B by adjusting the refrigerant flow rate that flows into each of the refrigerant branching passages 201 and 202.

(111) The refrigerant control unit 3 includes a refrigerant control valve 31 controlling the refrigerant flow rate that flows to the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B and a control device 32 controlling the refrigerant control valve 31. Also, the control device 32 is a general or exclusive computer including a CPU, a memory, an input output interface, an AD converter and the like, and controls the refrigerant control valve 31 by enabling the CPU, peripheral devices, and the like to cooperate with each other according to a control program stored in a predetermined area of the memory.

(112) The refrigerant control valve 31 of the embodiment is a 3-way valve installed at a branching point of the refrigerant branching passages 201 and 202. An input port is connected with a refrigerant tube on the side of the condenser 22, a first output port is connected with a branching tube configuring the refrigerant branching passage 201 on the side of the refrigerated compartment evaporator 23A, and a second output port is connected with a branching tube configuring the refrigerant branching passage 202 on the side of the freezer compartment evaporator 23B. The refrigerant control valve 31 individually controls the opening and closing of the first output port and the second output port using a control signal from the control device 32.

(113) Hereinafter, an embodiment of an opening and closing operation pattern of the refrigerant control valve 31 according to the control device 32 will be described with reference to FIG. 26.

(114) The control device 32 controls the refrigerant control valve 31 by sequentially performing a refrigerated compartment cooling operation of cooling the refrigerated compartment 11 and a freezer compartment cooling operation of cooling the freezer compartment 12, thereby selectively switching the evaporator that supplies a refrigerant between the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B. Also, in the embodiment, a simultaneous stop time period in which the refrigerant is not supplied to both sides of the evaporators 23A and 23B between the refrigerated compartment cooling operation and the freezer compartment cooling operation is set.

(115) Specifically, the control device 32 intermittently supplies the refrigerant by turning the refrigerant control valve 31 ON/OFF after switching between evaporators supplying the refrigerant (when the refrigerated compartment cooling operation or the freezer compartment cooling operation is performed). For example, after the evaporator supplying the refrigerant is switched into the refrigerated compartment evaporator 23A, the refrigerant control valve 31 is turned ON/OFF to intermittently supply the refrigerant to the refrigerated compartment evaporator 23A. Also, after the evaporator supplying the refrigerant is switched into the freezer compartment evaporator 23B, the refrigerant control valve 31 is turned ON/OFF to intermittently supply the refrigerant to the corresponding freezer compartment evaporator 23B.

(116) Here, the control device 32 performs duty control on the refrigerant control valve 31 and sets a cycle of the duty control from 3 to 200 seconds. Also, the control device 32 sets a time so that an ON-time of the refrigerant control valve 31 is longer than an OFF-time thereof in the duty control. The ON-time is a refrigerant supply time in which the refrigerant is supplied to the evaporator, and the OFF-time is a refrigerant collecting time in which the refrigerant (especially liquid refrigerant) is collected from the evaporator. Because of this, the refrigerant is certainly collected from the evaporator by setting the OFF-time to be longer than the ON-time. Also, the control device 32 sets a duty ratio (a time ratio) to control overheating by stabilizing a difference between an inlet temperature of the evaporator and an outlet temperature thereof between, for example, 0 to 10 C. Also, a cycle and the duty ratio in the duty control when the refrigerant is supplied to the refrigerated compartment evaporator 23A are the same as or different from a cycle and a duty ratio in the duty control when the refrigerant is supplied to the freezer compartment evaporator 23B.

(117) According to the cooling device 100 configured above, after the evaporator supplying the refrigerant is switched to any one side of the refrigerated compartment evaporator 23A or the freezer compartment evaporator 23B, the refrigerant is intermittently supplied by turning the refrigerant control valve 31 ON/OFF, thereby reducing a pressure loss generated by a liquid refrigerant in any one side of the corresponding refrigerated compartment evaporator 23A or the freezer compartment evaporator 23B, and suppressing an increase in the evaporator temperature. Therefore, it is possible to prevent heat exchange performance of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B from being degraded, prevent cooling efficiency from being degrading, and perform an energy saving operation. Also, the cooling time of the cooling chamber becomes appropriate, and the temperature quality of the cooling chamber is increased. Also, the possibility of liquid back-flowing to the compressor is reduced, and the durability of the compressor is improved.

(118) Also, when the control device 32 performs duty control on the refrigerant control valve 31, the ON-time in the refrigerant control valve 31 is set to be longer than the OFF-time, and thus the liquid refrigerant may be certainly collected from the evaporator supplying the refrigerant.

Modification of Fourth Embodiment

(119) The present invention is not limited to the fourth embodiment.

(120) For example, as shown in FIG. 27, the cooling device 100 may include defrosters 4A and 4B, for example a heater and the like, to remove frost from each of the refrigerated compartment evaporator 23A and the freezer compartment evaporator 23B. In this case, while frost is removed from one evaporator (for example, the freezer compartment evaporator 23B) by the defroster 4B, the refrigerant is supplied by the refrigerant control unit 3 to the evaporator (for example, refrigerated compartment evaporator 23A) from which the frost is not removed. Here, the control device 32 of the refrigerant control unit 3 intermittently supplies the refrigerant to one evaporator (for example, the refrigerated compartment evaporator) by turning the refrigerant control valve 31 ON/OFF. The opening and closing operation pattern of the refrigerant control valve 31 appears as shown in FIG. 28.

(121) Therefore, while frost is removed from the one side of the evaporators 23A and 23B by the defrosters 4A and 4B, the refrigerant control unit 3 intermittently supplies the refrigerant to an evaporator from which the frost is not removed by turning the refrigerant control valve 31 ON/OFF, thereby reducing a pressure loss generated by a liquid refrigerant in the corresponding evaporators 23A and 23B and suppressing an increase in the evaporator temperature. Therefore, the heat exchange performance of the evaporators 23A and 23B can be prevent from being degraded and an energy saving operation can be performed.

(122) Also, the control device 32 is installed outside the cooling device 100 to obtain a detected temperature from an external air temperature sensor detecting an external air temperature (an ambient temperature) so that the time ratio (the duty ratio) varies between the ON time and the OFF time of the refrigerant control valve 31 depending on the ambient temperature.

(123) Hereinabove, the present invention is not limited to each embodiment, and configurations described in each embodiment may be combined and variously modified without departing from the spirit and the scope of the present invention.