Abstract:
An object is to provide a beverage supply device which can cool cooling water in a water tank provided with a beverage cooling pipe by use of a cooling unit using a refrigerant having little influence on global environment, a beverage dispenser is provided with the beverage cooling pipe (syrup cooling pipe, diluting water cooling pipe, carbonated water cooling pipe) disposed in the water tank to store cooling water, the water tank being cooled by an evaporation pipe, the beverage dispenser passes syrup, diluting water, and carbonated water as beverage ingredients through the beverage cooling pipe to extract beverage, and the beverage dispenser comprises: a cooling unit in which a compressor, a radiator, a capillary tube, the evaporation pipe and the like are connected to one another via a pipe to constitute a refrigerant circuit and which is filled with carbon dioxide as the refrigerant.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a beverage supply device where a beverage cooling pipe is disposed in a water tank which stores cooling water and is cooled by a cooling unit, and a beverage or a beverage ingredient is passed through the beverage cooling pipe and extracted.  
         [0002]     Heretofore, as described in Japanese Patent Application Laid-Open No. 6-336291, a beverage supply device for cooling and supplying a beverage ingredient such as syrup or a beverage such as cooling water or beer has a constitution in which cooling water is stored in a water tank. The water tank is cooled by an evaporation pipe of a cooling unit to generate ice around the tank. A beverage cooling pipe is disposed in a coiled form in such water tank, and the beverage ingredient or the like is extracted through this beverage cooling pipe to thereby momentarily cool and supply the beverage ingredient.  
         [0003]     In the conventional beverage supply device, a refrigerant for use in the cooling unit is an HFC refrigerant which has been popular these days. However, such refrigerant is regarded as a cause for destroying an ozone layer, and there has been a demand for development of a refrigerant circuit using a refrigerant which has little influence on global environment from a viewpoint of protecting the global environment.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention has been developed to solve conventional technical problems, and there is provided a beverage supply device in which it is possible to cool cooling water in a water tank provided with a beverage cooling pipe by a cooling unit using a refrigerant which has little influence on global environment.  
         [0005]     In a first aspect of the present invention, a beverage supply device is provided with a beverage cooling pipe disposed in a water tank to store cooling water, the water tank being cooled by a cooler, and the beverage supply device passes a beverage or a beverage ingredient through the beverage cooling pipe to extract the beverage or the beverage ingredient. The beverage supply device comprises a cooling unit in which a compressor, a radiator, pressure reducing means, the cooler and the like are connected to one another via a pipe to constitute a refrigerant circuit and which is filled with carbon dioxide as a refrigerant.  
         [0006]     Moreover, in a second aspect of the present invention, the beverage supply device of the above-described invention further comprises: load detecting means for detecting a load on the compressor; and control means for controlling a rotational frequency of the compressor based on an output of the load detecting means.  
         [0007]     Furthermore, in a third aspect of the present invention, the beverage supply device of the above-described invention further comprises: a blower which air-cools the radiator, and the control means controls a fed air amount of the blower based on an output of the load detecting means.  
         [0008]     Additionally, in a fourth aspect of the present invention, in the beverage supply device of the second or third aspect of the present invention, the load detecting means is temperature detecting means for detecting a temperature of the radiator.  
         [0009]     Moreover, in a fifth aspect of the present invention, in the beverage supply device of the second or third aspect of the present invention, the load detecting means is temperature detecting means for detecting a temperature of the cooling water in the water tank.  
         [0010]     Furthermore, in a sixth aspect of the present invention, in the beverage supply device of the second or third aspect of the present invention, the load detecting means is temperature detecting means for detecting an outside air temperature.  
         [0011]     Additionally, in a seventh aspect of the present invention, in the beverage supply device of the second or third aspect of the present invention, the load detecting means is current detecting means for detecting an energizing current of the compressor.  
         [0012]     Moreover, in an eighth aspect of the present invention, in the beverage supply device of the second or third aspect of the present invention, the load detecting means is pressure detecting means for detecting a pressure in the refrigerant circuit.  
         [0013]     Furthermore, in a ninth aspect of the present invention, in the beverage supply device of the fourth, fifth, sixth, seventh, or eighth aspect of the present invention, the control means lowers the rotational frequency of the compressor and/or increases the fed air amount of the blower in a case where the temperature detected by the temperature detecting means, a current value detected by the current detecting means, or the pressure detected by the pressure detecting means rises.  
         [0014]     According to the first aspect of the present invention, the beverage supply device is provided with the beverage cooling pipe disposed in the water tank to store cooling water, the water tank being cooled by the cooler, and the beverage supply device passes the beverage or the beverage ingredient through the beverage cooling pipe to extract the beverage or the beverage ingredient. The beverage supply device comprises: the cooling unit in which the compressor, the radiator, the pressure reducing means, the evaporator and the like are connected to one another via the pipe to constitute the refrigerant circuit and which is filled with carbon dioxide as the refrigerant. Consequently, it is possible to cool the beverage cooling pipe disposed in the water tank without using any target refrigerant of control of chlorofluorocarbon as in a conventional art.  
         [0015]     Since carbon dioxide for use as the refrigerant has non-flammable and non-corrosive properties, does not destroy ozone, and has a global warming coefficient which is 1/1000 or less of that of a chlorofluorocarbon-based refrigerant, it is possible to provide a beverage supply device suitable for environment, that is, a device which realizes non-chlorofluorocarbon. Since carbon dioxide is much more easily obtained as compared with another refrigerant, convenience is improved.  
         [0016]     Moreover, according to the second aspect of the present invention, the device further comprises: the load detecting means for detecting the load on the compressor; and the control means for controlling the rotational frequency of the compressor based on the output of the load detecting means. Consequently, it is possible to avoid in advance a disadvantage that the compressor is brought into an overload operation.  
         [0017]     That is, even in a case where carbon dioxide having a low critical temperature is used as the refrigerant as in the above-described invention, when the load of the compressor is detected by the load detecting means, it is possible to avoid in advance disadvantages that a pressure of the refrigerant circuit on a high-pressure side increases and that a refrigerant circulated amount decreases. Accordingly, it is possible to avoid deterioration of a freezing capability in advance. In consequence, an operation efficiency of the compressor can be set to be appropriate, and a cooling efficiency can be improved.  
         [0018]     Moreover, the overload operation of the compressor can be avoided to prevent a disadvantage that the compressor stops by an operation of a safety system.  
         [0019]     Furthermore, in the third aspect of the present invention, the device of the above-described invention further comprises: the blower which air-cools the radiator, and the control means controls the fed air amount of the blower based on the output of the load detecting means. Consequently, even in a case where the pressure of the refrigerant circuit on the high-pressure side increases, when the fed air amount of the blower for the radiator is increased, the air-cooling of the radiator can be promoted. In consequence, the overload operation of the compressor can further be inhibited.  
         [0020]     Additionally, in the fourth aspect of the present invention, the load detecting means is constituted of the temperature detecting means for detecting the temperature of the radiator. Consequently, as in the ninth aspect of the present invention, the rotational frequency of the compressor can be lowered to thereby avoid in advance the overload operation of the compressor in a case where the temperature detected by the temperature detecting means rises. Moreover, in this case, when the fed air amount of the blower is increased, the air-cooling of the radiator can further be promoted, and the overload operation of the compressor can be effectively inhibited.  
         [0021]     Moreover, in the fifth aspect of the present invention, the load detecting means is constituted of the temperature detecting means for detecting the temperature of the cooling water in the water tank. Consequently, as in the ninth aspect of the present invention, the rotational frequency of the compressor can be lowered to thereby avoid in advance the overload operation of the compressor in a case where the temperature detected by the temperature detecting means rises. Moreover, in this case, when the fed air amount of the blower is increased, the air-cooling of the radiator can further be promoted, and the overload operation of the compressor can be effectively inhibited.  
         [0022]     Furthermore, in the sixth aspect of the present invention, the load detecting means is constituted of the temperature detecting means for detecting the outside air temperature. Consequently, as in the ninth aspect of the present invention, the rotational frequency of the compressor can be lowered to thereby avoid in advance the overload operation of the compressor in a case where the temperature detected by the temperature detecting means rises. Moreover, in this case, when the fed air amount of the blower is increased, the air-cooling of the radiator can further be promoted, and the overload operation of the compressor can be effectively inhibited.  
         [0023]     Additionally, in the seventh aspect of the present invention, the load detecting means is constituted of the current detecting means for detecting the energizing current of the compressor. Consequently, as in the ninth aspect of the present invention, the rotational frequency of the compressor can be lowered to thereby avoid in advance the overload operation of the compressor in a case where the current value detected by the current detecting means rises. Moreover, in this case, when the fed air amount of the blower is increased, the air-cooling of the radiator can further be promoted, and the overload operation of the compressor can be effectively inhibited.  
         [0024]     Moreover, in the eighth aspect of the present invention, the load detecting means is constituted of the pressure detecting means for detecting the pressure in the refrigerant circuit. Consequently, as in the ninth aspect of the present invention, the rotational frequency of the compressor can be lowered to thereby avoid in advance the overload operation of the compressor in a case where the pressure detected by the pressure detecting means rises. Moreover, in this case, when the fed air amount of the blower is increased, the air-cooling of the radiator can further be promoted, and the overload operation of the compressor can be effectively inhibited.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]      FIG. 1  is a front view of a beverage dispenser which utilizes the present invention;  
         [0026]      FIG. 2  is a side view of the beverage dispenser;  
         [0027]      FIG. 3  is a schematic constitution diagram of the beverage dispenser;  
         [0028]      FIG. 4  is a schematic constitution diagram showing a water tank and a cooling unit; and  
         [0029]      FIG. 5  is a schematic constitution diagram of the cooling unit. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     Embodiment 1  
       [0030]     In a first embodiment, a beverage dispenser  1  is a beverage dispenser for use in a restaurant, a coffee shop or the like, and is a device provided with: a BIB unit (not shown) which supplies neutral beverages such as oolong tea and orange juice; and a tank unit  4  which similarly supplies strongly and lightly carbonated and uncarbonated target beverages. Such beverage dispenser  1  has a structure in which the BIB unit is disposed in a main body  2 , and the tank unit  4  is externally connected to the main body. Moreover, the BIB unit is shielded behind an openably closed door  28  positioned in a front face of the main body. It is to be noted that the tank unit  4  will be described later in detail.  
         [0031]     The front face of the opening/closing door  28  is provided with an operation section  27  which supplies the beverage from the tank unit  4  and the BIB unit. The section is provided with operation buttons such as buttons S, M, L, and C/P which select a beverage supply amount or a beverage supply method for each beverage to be supplied from each unit. The buttons S, M, and L are buttons for supplying a predetermined amount of beverage, and the button C/P is a button for supplying the beverage only while operated.  
         [0032]     Furthermore, a multi-valve  12  (shown in  FIG. 3  only) for discharging each beverage from the tank unit  4  is disposed in a lower rear part of this opening/closing door  28 , and a table  14  is disposed under the nozzle  12  so that a cup is disposed on the table  14 .  
         [0033]     On the other hand, ingredients of the beverage supplied from the tank unit  4  include syrup as the beverage ingredient contained in a sealed container, for example, syrup (beverage ingredient) contained in a tank  3  and diluting water. In this case, when cooling water is used as diluting water, the uncarbonated beverage is supplied. When carbonated water is used, the strongly or lightly carbonated beverage is supplied. As shown in  FIG. 3 , the tank unit  4  is constituted by disposing: a syrup supply line  6  which supplies the syrup from the tank  3 ; a syrup cooling pipe (beverage cooling pipe)  7 ; a flow rate adjuster  8  driven by a driving motor  10 ; and a syrup electromagnetic valve  9 . An end portion of this syrup supply line  6  is connected to the other supply lines, that is, a cooling water supply line  24  and a carbonated water supply line  46  together with the multi-valve  12 . This multi-valve  12  mixes the syrup with diluting water or carbonated water to discharge the target beverage into a cup  50 .  
         [0034]     The tank  3  is connected to a carbon dioxide gas bomb  20  via a gas supply line  16  provided with a gas regulator  15 . Accordingly, the gas regulator  15  as a pressure reducing valve is always opened. Therefore, when the syrup electromagnetic valve  9  positioned on a downstream side of the syrup supply line  6  is opened, the carbon dioxide gas having a predetermined pressure is supplied from the carbon dioxide gas bomb  20  to feed the syrup to the syrup supply line  6 .  
         [0035]     The syrup cooling pipe  7  is immersed into a water tank  29  which stores cooling water cooled by a cooling unit R described later in detail to thereby cool the syrup flowing through the pipe  7 .  
         [0036]     The flow rate adjuster  8  continuously feeds a certain volume of syrup to the syrup supply line  6  by means of a pair of rotors  32 ,  32  stored in the adjuster. A shaft of one of the rotors  32  is connected to the driving motor  10 , and this motor  10  is provided with a magnet encoder  33  which generates a pulse having a frequency depending on a rotation speed of the motor  10 .  
         [0037]     Moreover, the energizing of the rotor driving motor  10  by the syrup electromagnetic valve  9  and the flow rate adjuster  8  is controlled by a control unit  11  described later. Accordingly, the syrup is fed from the tank  3  to the multi-valve  12  connected to the end portion of the syrup supply line  6 , and the supplying of the syrup is controlled.  
         [0038]     On the other hand, in the main body  2 , there is disposed a diluting water supply pipe  17  which supplies tap water such as city water as diluting water. This diluting water supply pipe  17  is successively connected to a water inlet electromagnetic valve  18 , a water pump  19 , a diluting water cooling pipe (beverage cooling pipe)  21 , a diluting water flow meter  22 , and the diluting water supply line  24 . It is to be noted that the diluting water cooling pipe  21  cools diluting water circulating in the diluting water cooling pipe  21  by means of cooling water cooled by the cooling unit R described later in detail in the same manner as in the syrup cooling pipe  7 .  
         [0039]     The diluting water flow meter  22  outputs a flow rate signal to the control unit  11  depending on a flow rate of inflowing diluting water. The diluting water supply line  24  is provided with a diluting water electromagnetic valve  25 , so that opening/closing of the diluting water supply line  24  is controlled. It is to be noted that the diluting water supply line  24  is connected to the multi-valve  12  in the same manner as in the syrup supply line  6 . Accordingly, the diluting water electromagnetic valve  25  is controlled by the control unit  11  to control the supplying of the diluting water to the multi-valve  12 .  
         [0040]     Moreover, the diluting water supply line  24  is connected to a water branch line  38  which is positioned between the diluting water flow meter  22  and the diluting water electromagnetic valve  25  and which is provided with an electromagnetic valve  39 . This water branch line  38  is connected to a carbonator  40  for manufacturing carbonated water. Moreover, the carbonator  40  is connected to a gas supply line  42  whose one end is connected to the carbon dioxide gas bomb  20 . The gas supply line  42  is provided with a gas regulator  41 . Accordingly, diluting water is supplied to the carbonator  40  via the water branch line  38 . Moreover, the carbon dioxide gas is supplied to the carbonator via the gas supply line  42 , and diluting water is mixed with the carbon dioxide gas to generate carbonated water.  
         [0041]     Furthermore, this carbonator  40  is connected to a carbonated water supply line  46  provided with a carbonated water flow meter  43 , a carbonated water cooling pipe (beverage cooling pipe)  44 , and a carbonated water electromagnetic valve  45 , and an end portion of the carbonated water supply line  46  is connected to the multi-valve  12 .  
         [0042]     The carbonated water flow meter  43  outputs a flow rate signal to the control unit  11  depending on the flow rate of inflowing carbonated water. It is to be noted that the carbonated water cooling pipe  44  cools carbonated water circulating in the carbonated water cooling pipe  44  by means of cooling water cooled by the cooling unit R described later in detail in the same manner as in the syrup cooling pipe  7 . The carbonated water electromagnetic valve  45  disposed on the carbonated water supply line  46  controls opening/closing of the carbonated water supply line  46 . It is to be noted that the carbonated water supply line  46  is connected to the multi-valve  12  in the same manner as in the syrup supply line  6 . Therefore, the carbonated water electromagnetic valve  45  is controlled by the control unit  11  to control the supplying of carbonated water to the multi-valve  12 .  
         [0043]     There will be described a beverage supplying operation of the beverage dispenser  1  constituted as described above. The carbon dioxide gas is supplied from the carbon dioxide gas bomb  20  to the carbonator  40  via the gas supply line  42  beforehand. It is also assumed that diluting water is supplied from the water branch line  38  to the carbonator via the diluting water supply line  24 , carbonated water having a predetermined carbon dioxide concentration is manufactured and stored, and the device is brought into a standby state for dispensing.  
         [0044]     When any of the operation buttons of the operation section  27  is operated in the standby state for the dispensing, the beverage is supplied in accordance with the button operation. Here, when the uncarbonated beverage button is operated, the control unit  11  opens the water inlet electromagnetic valve  18 , and allows tap water supplied from city water via the water pump  19  to flow into the diluting water supply line  24  via the diluting water cooling pipe  21  and the diluting water flow meter  22 . The control unit  11  controls the energizing of the rotor driving motor  10  which drives the syrup electromagnetic valve  9  and the flow rate adjuster  8 , and accordingly allows the syrup supplied from the tank  3  to flow into the syrup supply line  6  via the syrup cooling pipe  7  and the flow rate adjuster  8 . Accordingly, the syrup is diluted with diluting water at a predetermined ratio to generate a target beverage, and the beverage is supplied from the multi-valve  12  to the cup  50 .  
         [0045]     When the carbonated beverage button is operated, the control unit  11  opens the water inlet electromagnetic valve  18 , and allows tap water supplied from city water via the water pump  19  to flow into the diluting water supply line  24  via the diluting water cooling pipe  21  and the diluting water flow meter  22 . Furthermore, the opening/closing of the electromagnetic valve  39  and the carbonated water electromagnetic valve  45  is controlled to discharge a predetermined amount of carbonated water from the carbonator  40  to the multi-valve  12 . Even in this case, when the predetermined amount of syrup is supplied to the syrup supply line  6  in the same manner as described above, the syrup is diluted with carbonated water at the predetermined ratio to generate the target beverage, and the beverage is supplied to the cup  50  via the multi-valve  12 .  
         [0046]     Next, there will be described a constitution of the water tank  29  and the cooling unit R with reference to  FIGS. 4 and 5 . The water tank  29  opens upwards, cooling water is stored in the tank, and an insulating wall  50  is disposed as a peripheral wall to insulate water. Under this water tank  29 , there is disposed the cooling unit R constituted of a compressor  51 , a radiator  52 , a blower  53  for air-cooling the radiator  52  and the like.  
         [0047]     As shown in  FIG. 5 , as the cooling unit R, there is used an intermediate inner pressure type multistage (two stages) compression type rotary compressor provided with an electromotive element (not shown) as the compressor  51 , and first and second rotary compression elements  54 ,  55 . As this compressor  51 , an inverter system is adopted, and the rotational frequency of the compressor can be arbitrarily adjusted by means of the connected control unit  11 .  
         [0048]     Moreover, in the cooling unit R, there are successively connected via a refrigerant pipe  56 : the first rotary compression element  54  of the compressor  51 ; an intermediate heat exchanger  57 ; the second rotary compression element  55  of the compressor  51 ; the radiator  52 ; a radiating section  58 A of an inner heat exchanger  58 ; a capillary tube  59  as pressure reducing means; an evaporation pipe  30  as a cooler; and a heat absorbing section  58 B of the inner heat exchanger  58 . Accordingly, an annular freezing cycle is constituted.  
         [0049]     Here, the radiating section  58 A of the inner heat exchanger  58  exchanges heat with the cooling section  58 B in which the refrigerant discharged from the evaporation pipe  30  circulates. The refrigerant circuit of this cooling unit R is filled with carbon dioxide as an eco-friendly natural refrigerant in consideration of flammability, toxicity and the like. The radiator  52  is provided with the blower  53  for ventilation. In  FIG. 5 , reference numeral  60  denotes a radiator temperature sensor (temperature detecting means as load detecting means) which detects a temperature of the radiator  52 , and operations of the compressor  51  and the blower  53  are controlled based on an output of the radiator temperature sensor  60 .  
         [0050]     The evaporation pipe  30  constituting the freezing cycle of the cooling unit R together with the compressor  51  and the radiator  52  is inserted into the water tank  29  in a coiled state, and the pipe is immerged into cooling water of the water tank  29  to cool cooling water. On the other hand, the coiled beverage cooling pipes  7 ,  21 , and  44  are inserted into the water tank  29  from above, and submerged in cooling water. It is to be noted that  FIG. 4  shows the syrup cooling pipe  7  only, but it is assumed that the diluting water cooling pipe  21  and the carbonated water cooling pipe  44  are additionally inserted.  
         [0051]     Moreover, an ice sensor  67  is disposed behind the evaporation pipes  30 . This ice sensor  67  is constituted of two electrodes to detect an ice layer I around the evaporation pipe  30  from a change of a resistance value between the opposite electrodes. That is, when water is disposed between the electrodes, a low resistance value is indicated. When ice is disposed between them, a high resistance value is indicated. Therefore, the generation of the ice layer I is detected depending on such resistance value change.  
         [0052]     A stirrer  64  is disposed in the water tank  29 . The stirrer  64  is rotated by a motor  68 . Four radially extending guide plates  66  are attached to the top of a bottom wall  29 A of the water tank  29 . The evaporation pipes  30  and lower end portions of the beverage cooling pipes  7  are held on upper edges of the guide plates  66 , respectively.  
         [0053]     There will be described an operation of the beverage supply device  1  of the present invention constituted as described above. When the beverage supply device  1  is installed, and power supply is turned on, the control unit  11  starts the compressor  51  of the cooling unit R to start the operation. When the electromotive element of the compressor  51  is energized, the element starts to rotate a rotors. This rotation allows upper and lower rollers (not shown) fitted into upper and lower eccentric portions (not shown) disposed integrally with a rotation shaft (not shown) to eccentrically rotate in upper and lower cylinders constituting the first and second rotary compression elements  54 ,  55 . Accordingly, a low-pressure refrigerant gas sucked into the lower cylinder of the first rotary compression element  54  on the side of a low-pressure chamber is compressed by functions of the lower roller and vane to achieve an intermediate pressure. The gas is discharged from the lower cylinder on the high-pressure chamber side into the sealed container of the compressor  51 . This brings the inside of the sealed container into the intermediate pressure.  
         [0054]     Moreover, the intermediate-pressure refrigerant gas in the sealed container once flows out of the sealed container, and passes through the intermediate heat exchanger  57 . The refrigerant is air-cooled in the exchanger, and in turn sucked into the upper cylinder of the second rotary compression element  55  in the sealed container. The gas is compressed in a second stage by functions of the upper roller and vane, and turns to a high-temperature high-pressure refrigerant gas. The gas is discharged from the high-pressure chamber side to the outside. In this case, the refrigerant has a temperature of about +86° C., and is compressed at an appropriate supercritical pressure.  
         [0055]     In this case, as described above, the compressor  51  is an intermediate inner pressure type multistage (two stages) compression rotary compressor provided with the first and second rotary compression elements  54  and  55 . That is, since the refrigerant sucked and compressed in the first rotary compression element  54  can be sucked and compressed by the second rotary compression element  55 , it is possible to efficiently compress the carbon dioxide refrigerant under the supercritical pressure.  
         [0056]     Furthermore, since the refrigerant discharged from the first rotary compression element  54  radiates heat by means of the intermediate heat exchanger  57 , an amount of heat can be balanced. The intermediate heat exchanger  57  radiates heat from the refrigerant discharged from the first rotary compression element  54  so as to raise a density of refrigerant sucked into the second rotary compression element  55 . A compression efficiency can thus be improved.  
         [0057]     As described above, the refrigerant gas discharged from the compressor  51  flows into the radiator  52 , and radiates heat by means of the ventilation by the blower  53 . It is to be noted that in this case, the temperature of the radiator  52  is detected by the radiator temperature sensor  60 . Based on the temperature, the rotational frequency of the compressor  51  is controlled, and the blower  53  is adjusted into a predetermined temperature.  
         [0058]     Moreover, the refrigerant discharged from the radiator  52  flows into the radiating section  58 A of the inner heat exchanger  58  to exchange heat with the heat absorbing section  58 B disposed so as to exchange heat with the radiating section  58 A. Accordingly, heat is taken to cool the refrigerant. It is to be noted that the refrigerant (carbon dioxide) compressed under the supercritical pressure is used in the cooling unit R of the present invention. Therefore, in the radiating section  58 A, the refrigerant maintains its gas state without being liquefied, and the temperature drops.  
         [0059]     The refrigerant gas on the high-pressure side is cooled in the radiating section  58 A as described above, and reaches the capillary tube  59 . The refrigerant gas still has the gas state in the inlet to the capillary tube  59 , but turns to a two-phase mixture of gas and liquid owing to the pressure drop in the capillary tube  59 . In this state, the refrigerant flows into the evaporation pipe  30 . In the pipe, the refrigerant evaporates to cool cooling water in the water tank  29  by means of a heat absorbing function generated by the evaporation (in this case, the refrigerant has a temperature at about −5° C.).  
         [0060]     The ice layer I is generated on an outer periphery of the evaporation pipe  30  during the cooling. When ice is generated between the electrodes of the ice sensor  67 , the resistance value between the electrodes rises as described above. Therefore, the control unit  11  stops the compressor  51 . Thereafter, when the ice between the electrodes melts, the resistance value between the electrodes lowers as described above. Therefore, the control unit  11  starts the compressor  51 . The ice layer I having a certain thickness is generated around the evaporation pipe  30  under such control. Therefore, the beverage cooling pipes  7 ,  21 , and  44  are cooled by latent heat of this ice layer I.  
         [0061]     Moreover, the refrigerant discharged from the evaporation pipe  30  flows into the heat absorbing section  58 B of the inner heat exchanger  58  to exchange heat with the radiating section  58 A which is disposed so as to exchange heat with the heat absorbing section  58 B. It is to be noted that the refrigerant exchanges heat with the cooling water or the radiating section  58 A to achieve the gas state, and is again sucked into the first rotary compression element  54  of the compressor  51 .  
         [0062]     In the present invention, the refrigerant circuit of the cooling unit R is filled with carbon dioxide as the refrigerant. Since carbon dioxide is a substance which does not destroy ozone, non-chlorofluorocarbon can be realized, and a global warming coefficient can be set to 1/1000 or less of that of a chlorofluorocarbon-based refrigerant. Since carbon dioxide is much more easily obtained as compared with another refrigerant, convenience is improved.  
         [0063]     Here, when the power supply is turned on, the control unit  11  sets the rotational frequency of the compressor  51  to, for example, 50 Hz, and the blower  53  of the radiator  52  is set to the usual rotational frequency to operate. On the other hand, in the present invention, carbon dioxide is used as the refrigerant of the refrigerant circuit of the cooling unit R. Therefore, since the critical temperature of carbon dioxide is low at about +31° C., the radiator  52  is sometimes brought into a supercritical pressure state in which the carbon dioxide refrigerant is not liquefied even if the refrigerant radiates heat at a usual outside air temperature. In this case, the pressure of the refrigerant circuit on the high-pressure side increases, a circulating refrigerant amount drops, and a freezing capability largely deteriorates. Therefore, the compressor  51  is brought into an overload operation state, and a freezing operation cycle is performed with a low efficiency.  
         [0064]     Moreover, in the present embodiment, when the temperature detected by the radiator temperature sensor  60  is higher than, for example, +20° C. and lower than +40° C., the control unit  11  sets the rotational frequency of the compressor  51  to 50 Hz as described above, and the blower  53  of the radiator  52  is set to the usual rotational frequency, and operated. Moreover, when the temperature detected by the radiator temperature sensor  60  rises at, for example, +40° C. or more, the control unit  11  sets the rotational frequency of the compressor  51  down to, for example, 40 Hz, and sets the blower  53  to a predetermined high rotation-speed to operate the blower.  
         [0065]     Consequently, the overload operation of the compressor  51  is judged in advance by the temperature of the radiator  52 , and the rotational frequency of the compressor  51  is lowered. This inhibits a rise of the pressure of the refrigerant circuit on the high-pressure side, the compressor  51  can be operated in a stabilized state, and the operation can be realized with a good cooling efficiency. Therefore, it is possible to avoid a disadvantage that the pressure of the refrigerant circuit on the high-pressure side rises to increase power consumption. It is possible to avoid in advance a disadvantage that a safety system or the like operates to stop the operation, when the overload operation of the compressor  51  reaches its limitation.  
         [0066]     Moreover, in this case, when the blower  53  is operated at a high speed with the temperature rise of the radiator  52 , the air-cooling of the radiator  52  can be promoted, and the overload operation of the compressor  51  can further be inhibited.  
         [0067]     It is to be noted that when the temperature detected by the radiator temperature sensor  60  drops at, for example, +20° C. or less, the control unit  11  raises the rotational frequency of the compressor  51  to 60 Hz, and ice can be quickly generated.  
       Embodiment 2  
       [0068]     There will be described hereinafter use of an outside air temperature sensor in load detecting means in a second embodiment. It is to be noted that a control unit  11  is connected to an outside air temperature sensor  70  as the load detecting means disposed in a main body  2  in order to detect an outside air temperature at which a beverage dispenser  1  is disposed as shown in  FIG. 5 .  
         [0069]     When the temperature detected by the outside air temperature sensor  70  is higher than, for example, +10°C. and lower than +30° C. in such embodiment, the control unit  11  sets a rotational frequency of a compressor  51  to 50 Hz as described above, and sets the rotational frequency of a blower  53  of a radiator  52  to a usual rotational frequency to operate the blower. Moreover, when the temperature detected by the outside air temperature sensor  70  rises at, for example, +30° C. or more, the control unit  11  lowers the rotational frequency of the compressor  51  at 40 Hz, and operates the blower  53  at a predetermined high rotational frequency.  
         [0070]     Consequently, when an overload operation of the compressor  51  is judged in advance by an outside air temperature, and the rotational frequency of the compressor  51  is lowered, a rise of pressure of a refrigerant circuit on a high-pressure side is inhibited, the compressor  51  can be operated in a stabilized state, and the operation can be realized with a good cooling efficiency. Even in this case, it is possible to avoid a disadvantage that the pressure of the refrigerant circuit on the high-pressure side rises to increase power consumption. It is possible to avoid in advance a disadvantage that a safety system or the like operates to stop the operation, when the overload operation of the compressor  51  reaches its limitation.  
         [0071]     Even in this case, when the rotational frequency of the blower  53  is set to be high to operate the blower with the rise of the outside air temperature, air-cooling of the radiator  52  can be promoted, and the overload operation of the compressor  51  can further be inhibited.  
         [0072]     It is to be noted that when the temperature detected by the outside air temperature sensor  70  drops at, for example, +10° C. or less, the control unit  11  raises the rotational frequency of the compressor  51  to 60 Hz, and ice can be generated quickly.  
       Embodiment 3  
       [0073]     There will be described hereinafter use of a cooling water temperature sensor in load detecting means in a third embodiment. In this case, a cooling water temperature sensor  69  is disposed in a water tank  29  in order to detect a temperature of pooled cooling water. It is assumed that the cooling water temperature sensor  69  is connected to a control unit  11 .  
         [0074]     When the temperature detected by the cooling water temperature sensor  69  is higher than, for example, +1° C. and lower than +5° C. in such embodiment, the control unit  11  sets a rotational frequency of a compressor  51  to 50 Hz as described above, and sets the rotational frequency of a blower  53  of a radiator  52  to a usual rotational frequency to operate the blower. Moreover, when the temperature detected by the cooling water temperature sensor  69  rises at, for example, +5° C. or more, the control unit  11  lowers the rotational frequency of the compressor  51  at 40 Hz, and operates the blower  53  at a predetermined high rotational frequency.  
         [0075]     Even in this case, when an overload operation of the compressor  51  is judged in advance by the temperature of the cooling water of the water tank  29 , and the rotational frequency of the compressor  51  is lowered, a rise of pressure of a refrigerant circuit on a high-pressure side is inhibited, the compressor  51  can be operated in a stabilized state, and the operation can be realized with a good cooling efficiency. Even in this case, it is possible to avoid a disadvantage that the pressure of the refrigerant circuit on the high-pressure side rises to increase power consumption. It is possible to avoid in advance a disadvantage that a safety system or the like operates to stop the operation, when the overload operation of the compressor  51  reaches its limitation.  
         [0076]     Even in this case, when the rotational frequency of the blower  53  is set to be high to operate the blower with the temperature rise of the cooling water in the water tank  29 , air-cooling of the radiator  52  can be promoted, and the overload operation of the compressor  51  can further be inhibited.  
         [0077]     It is to be noted that when the temperature detected by the cooling water temperature sensor  69  drops at, for example, +1° C. or less, the control unit  11  raises the rotational frequency of the compressor  51  to 60 Hz, and ice can be generated quickly.  
       Embodiment 4  
       [0078]     There will be described hereinafter use of energizing current value detecting means of a compressor  51  in load detecting means in a fourth embodiment. In this case, a compressor  51  is provided with a current value detecting sensor  71  for detecting an energizing current value of the compressor  51  as shown in  FIG. 5 . It is assumed that the current value detecting sensor  71  is connected to a control unit  11 .  
         [0079]     When the energizing current value detected by the current value detecting sensor  71  is higher than a predetermined lower limit value and lower than an upper limit value in such embodiment, the control unit  11  sets a rotational frequency of a compressor  51  to 50 Hz as described above, and sets the rotational frequency of a blower  53  of a radiator  52  to a usual rotational frequency to operate the blower. Moreover, when the energizing current value detected by the current value detecting sensor  71  rises to the predetermined upper limit value, the control unit  11  lowers the rotational frequency of the compressor  51  at, for example, 40 Hz, and operates the blower  53  at a predetermined high rotational frequency.  
         [0080]     Consequently, an overload operation of the compressor  51  can be judged directly by the energizing current value to the compressor  51 . Therefore, the rotational frequency of the compressor  51  can be lowered to inhibit a rise of pressure of a refrigerant circuit on a high-pressure side, the compressor  51  can be operated in a stabilized state, and the operation can be realized with a good cooling efficiency. Even in this case, it is possible to avoid a disadvantage that the pressure of the refrigerant circuit on the high-pressure side rises to increase power consumption. It is possible to avoid in advance a disadvantage that a safety system or the like operates to stop the operation, when the overload operation of the compressor  51  reaches its limitation.  
         [0081]     Even in this case, when the rotational frequency of the blower  53  is set to be high to operate the blower, air-cooling of the radiator  52  can be promoted, and the overload operation of the compressor  51  can further be inhibited.  
         [0082]     It is to be noted that when the energizing current value detected by the current value detecting sensor  71  drops to a value that is not more than a predetermined lower limit value, the control unit  11  raises the rotational frequency of the compressor  51  to 60 Hz, and ice can be generated quickly.  
       Embodiment 5  
       [0083]     There will be described hereinafter a case where pressure detecting means for detecting a pressure in a refrigerant circuit is used in load detecting means in a fifth embodiment. In this case, a radiator  52  is provided with a pressure sensor  72  for detecting the pressure in the radiator  52  as shown in  FIG. 5 . It is assumed that the pressure sensor  72  is connected to a control unit  11 .  
         [0084]     When the pressure in the radiator  52  detected by the pressure sensor  72  is higher than a predetermined lower limit value and lower than an upper limit value in such embodiment, the control unit  11  sets a rotational frequency of a compressor  51  to 50 Hz as described above, and sets the rotational frequency of a blower  53  of a radiator  52  to a usual rotational frequency to operate the blower. Moreover, when the pressure detected by the pressure sensor  72  rises to the predetermined upper limit value, the control unit  11  lowers the rotational frequency of the compressor  51  to, for example, 40 Hz, and operates the blower  53  at a predetermined high rotational frequency.  
         [0085]     Consequently, an overload operation of the compressor  51  can be judged by the pressure in the radiator  52 . Therefore, the rotational frequency of the compressor  51  can be lowered to inhibit a rise of pressure of a refrigerant circuit on a high-pressure side, the compressor  51  can be operated in a stabilized state, and the operation can be realized with a good cooling efficiency. Even in this case, it is possible to avoid a disadvantage that the pressure of the refrigerant circuit on the high-pressure side rises to increase power consumption. It is possible to avoid in advance a disadvantage that a safety system or the like operates to stop the operation, when the overload operation of the compressor  51  reaches its limitation.  
         [0086]     Even in this case, when the rotational frequency of the blower  53  is set to be high to operate the blower, air-cooling of the radiator  52  can be promoted, and the overload operation of the compressor  51  can further be inhibited.  
         [0087]     It is to be noted that when the pressure detected by the pressure sensor  72  drops to a value that is not more than a predetermined lower limit value, the control unit  11  raises the rotational frequency of the compressor  51  to 60 Hz, and ice can be generated quickly.  
         [0088]     It is to be noted that in the above-described embodiments, the present invention is applied to the beverage supply device which extracts various types of beverages such as juice, but the present invention is not limited to the device, and is effective even for a beverage supply device which extracts cold water or beer.