JP4872350B2 - vending machine - Google Patents

Description

  The present invention relates to a vending machine having a cooling system equipped with an inverter compressor in a vending machine that cools and sells products such as canned beverages.

  In recent years, while environmental protection has been screamed, the vending machine industry has been promoting energy saving with the introduction of the top runner system.

  Under such circumstances, the refrigerator industry, which has a similar cooling system and is ahead of energy conservation, has recently been subject to load fluctuations such as food in and out in order to improve cooling system efficiency and promote energy conservation. Accordingly, an inverter compressor capable of optimally controlling the rotation speed of the compressor has been used.

  Here, when an inverter compressor is used, the refrigerant circulation amount changes depending on the rotation speed of the compressor. Therefore, if the amount of refrigerant supplied to the evaporator is not optimized by a variable throttle mechanism such as an expansion valve, inverter compression The performance of the machine cannot be fully demonstrated and the cooling system efficiency cannot be improved. However, since such a throttling mechanism cannot exchange heat with the suction pipe from the evaporator to the compressor, the cooling system efficiency cannot be further improved.

  In view of this, a refrigerator in which two or more capillary tubes having different tube diameters are arranged in parallel so as to be switchable has been proposed as a means for sufficiently exhibiting the performance of the inverter compressor (see, for example, Patent Document 1).

  Hereinafter, a refrigerator including a conventional cooling system will be described with reference to the drawings.

  FIG. 4 is a refrigerant circuit diagram of a conventional refrigerator described in Patent Document 1.

  As shown in FIG. 4, the conventional refrigerator includes an inverter compressor 1, a condenser 2, a first valve 3, a second valve 4, a first capillary tube 5, a second capillary tube 6, and an evaporator 7. A cooling system composed of

  Furthermore, the pipeline from the condenser 2 to the evaporator 7 is branched into two, and the first valve 3 and the first capillary tube 5 are arranged in one pipeline, and the other pipeline is arranged in the other pipeline. A second valve 4 and a second capillary tube 6 are arranged.

  Here, the diameters of the first capillary tube 5 and the second capillary tube 6 are different. That is, the channel resistance is different. Further, the capillary tubes 5 and 6 are fixed in contact with suction pipes from the evaporator 7 to the inverter compressor 1, respectively.

  About the refrigerator comprised as mentioned above, the operation | movement is demonstrated below.

  The refrigerant discharged from the inverter compressor 1 is condensed by the condenser 2, and then the first capillary tube 5, the second capillary tube 6, or the first valve 3 and the second valve 4 are opened and closed. Supplied to both. Then, the pressure is reduced by the capillary tube, evaporated by the evaporator 7, and then refluxed to the inverter compressor 1.

  Thus, when a refrigerant | coolant evaporates with the evaporator 7, it cools by the effect | action which takes the heat in a refrigerator.

Here, which capillary tube is used is determined from the rotation speed and the condensation temperature of the inverter compressor 1. For example, when the rotation speed is low, a capillary tube having a small flow path resistance, that is, a large tube diameter is used. When the rotational speed is high, a capillary tube having a large flow resistance, that is, a small tube diameter is used. Further, the channel resistance is decreased when the condensation temperature is high, and the channel resistance is increased when the condensation temperature is low.
JP 2001-124453 A

  Here, the difference in the use state of a vending machine and a refrigerator is demonstrated.

  FIG. 5 is a characteristic diagram showing the range of use of conventional vending machines and refrigerators.

  In FIG. 5, the vertical axis indicates the internal temperature, and the horizontal axis indicates the outside temperature. Moreover, the area | region enclosed with the thick dotted line has shown the use range of the refrigerator, and the area | region enclosed by the continuous line has shown the use range of the vending machine.

  First, the usage state of the refrigerator will be described. Since the refrigerator is installed indoors, it is rarely used in a state where the outside air temperature is abnormally high. In addition, since the refrigerator is usually not cooled in a large amount at a time even if it has already been chilled to some extent, or food with a high temperature, the temperature in the refrigerator is rarely very high.

  On the other hand, vending machines are filled with a large amount of products having a temperature equivalent to the outside air temperature, or are installed outdoors, and thus are exposed to a very high outside air temperature. That is, a large cooling capacity higher than that of the refrigerator is required at a high load, and for that purpose, in addition to operating the inverter compressor at a high rotation speed, it is desirable to increase the evaporation temperature as much as possible and increase the refrigerant circulation rate. .

  However, if the evaporating temperature is set high, liquid return to the compressor occurs with a decrease in the internal temperature, the cooling system efficiency deteriorates, and the possibility that the compressor breaks down increases. Further, in a state where the outside air temperature is high, the limit value has a problem that it rapidly increases as shown by a one-dot chain line in FIG.

  In addition, the condensation temperature increases at high outside temperatures, and the evaporation temperature increases accordingly. If the limit indicated by the two-dot chain line in FIG. 5 is exceeded, the possibility of compressor failure such as breakage of the intake valve increases. It had the problem that.

  On the other hand, when the product temperature is stable and the load is low, low capacity similar to that of a refrigerator is sufficient, and the cooling capacity needs to be changed greatly between high load and low load.

  Therefore, the control method for switching the capillary tube based on the rotation speed and the condensation temperature as in the conventional refrigerator is not suitable for a vending machine in which the required cooling capacity changes greatly, and ensures the reliability of the compressor. Is a problem.

  The present invention solves the conventional problems. The cooling system efficiency is ensured when the product temperature is stable and the load is low while sufficiently securing the cooling capacity required at the time of high load such as product replenishment or high outside air temperature. The purpose of this invention is to provide a vending machine that can improve the energy efficiency and save energy and can ensure the reliability of the compressor.

In order to solve the above-described conventional problems, the vending machine of the present invention includes at least an evaporator installed in a warehouse for storing products, a condenser installed outside a compartment for storing products, and inverter compression a machine, a diaphragm mechanism, a cooling system comprising a cooling system piping which connects the inverter compressor and the condenser and the throttle mechanism and the evaporator annularly flow path resistance as the throttle mechanism A plurality of different capillary tubes are arranged in parallel, the capillary tube is configured to be switchable by the flow path switching means , the chamber temperature Ti detected by the chamber temperature sensor is higher than the reference temperature Til, and the outside air temperature The outside air temperature To detected by the sensor is higher than the reference temperature Tol, and the evaporation temperature Te detected by the evaporation temperature sensor installed in the evaporator is Higher than reference temperature Tel is to switch to a larger capillary tube flow resistance.

  As a result, the cooling capacity can be greatly changed, and liquid return to the compressor and abnormal increase in the evaporation temperature can be prevented.

The vending machine of the present invention has a high cooling capacity at high load by switching the channel resistance according to the inside temperature, the outside temperature, and the evaporation temperature detected by the evaporation temperature sensor installed in the evaporator. It is possible to achieve both high efficiency at low load, save energy, and ensure the reliability of the compressor.

The invention according to claim 1 includes at least an evaporator installed in a warehouse for storing products, a condenser installed outside a compartment for storing products, an inverter compressor, a throttle mechanism, and the inverter A cooling system having a cooling system pipe connecting the compressor, the condenser, the throttle mechanism, and the evaporator in an annular shape, and a plurality of capillary tubes having different flow resistances arranged in parallel as the throttle mechanism; The capillary tube is configured to be switchable by the flow path switching means, the inside temperature Ti detected by the inside temperature sensor is higher than the reference temperature Til, and the outside temperature To detected by the outside temperature sensor is When the temperature is higher than the reference temperature Tol and the evaporation temperature Te detected by the evaporation temperature sensor installed in the evaporator is higher than the reference temperature Tel By switching the flow path resistance of the high capillary tube, to optimize the refrigerant circulation amount in accordance with the state of the load, it is possible to supply just enough refrigerant to the evaporator, it is possible to improve the cooling system efficiency Since the suction pipe from the evaporator to the inverter compressor and the capillary tube can be heat-exchanged, the efficiency of the cooling system can be further improved and energy saving can be achieved. In addition, since the evaporation temperature can be prevented from rising excessively, the reliability of the compressor can be ensured.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same configurations as those of the conventional example or the embodiments described above, and detailed descriptions thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigerant circuit diagram of a vending machine according to Embodiment 1 of the present invention.

  In FIG. 1, the vending machine of the present invention includes a storage room 11 for storing products such as canned beverages, and a machine room 12, and includes an inverter compressor 1, a condenser 2, and a storage room installed in the machine room 12. 11 includes an evaporator 7, a first capillary tube 5 arranged in parallel as a throttling mechanism, a second capillary tube 6, and a three-way switching valve 13 that switches which capillary tube the refrigerant is to flow through. It has a system 14.

  Here, the flow path resistance of the first capillary tube 5 is smaller than the flow path resistance of the second capillary tube 6. That is, the inner diameter of the first capillary tube 5 is larger than that of the second capillary tube 6. The first capillary tube 5 and the second capillary tube 6 are fixed in contact with each other so as to be able to exchange heat with the suction pipe 15 that guides the refrigerant from the evaporator 7 to the inverter compressor 1.

  In this embodiment, since two capillary tubes are used, the three-way switching valve 13 is used as the refrigerant flow path switching means. However, an electromagnetic valve or the like is used in accordance with the number of capillary tubes to be used. May be used. In this embodiment, an electromagnetic valve may be used. However, since this leads to an increase in power consumption, it is desirable to use a three-way switching valve.

  Further, the storage chamber 11 has an internal temperature sensor 16 for detecting the internal temperature, the outside of the storage chamber 11 has an external temperature sensor 17 for detecting the external temperature, and the inlet pipe of the evaporator 7 has an evaporation temperature for detecting the evaporation temperature. Each temperature sensor 18 is installed.

  Based on the temperature information detected by each temperature sensor 16, 17, 18, the controller 19 controls the operation of the three-way switching valve 13 and the inverter compressor 1.

  The operation and action of the vending machine configured as described above will be described below.

  In addition, about the basic operation | movement and effect | action which cool the storage chamber 11, since it is the same as that of the cooling system of a prior art example, it abbreviate | omits.

  FIG. 2 is a characteristic diagram showing the operation of the vending machine according to the embodiment in relation to the inside temperature and the outside air temperature.

  In FIG. 2, the one-dot chain line and the two-dot chain line indicate the limit of occurrence of liquid return to the inverter compressor 1 and the allowable limit of the evaporation temperature Te, respectively, as in FIG. And the amount of refrigerant enclosed.

  Here, when a plurality of capillary tubes having different flow path resistances are used as in the present embodiment, there is a difference in the optimum refrigerant filling amount in each flow path resistance, and the smaller the flow path resistance, the more the inverter compression Liquid return to the machine 1 is likely to occur. For this reason, in the present embodiment, the refrigerant filling amount is determined in the first capillary tube 5 having a small channel resistance.

  First, the outside air temperature at which the initial pull-down performance must be guaranteed is the outside air reference temperature Tol. Below this reference temperature Tol, the evaporating temperature Te does not exceed the limit value, and the first capillary is set so that the cooling capacity is maximized. The tube 5 and the refrigerant filling amount were determined.

  Then, the limit temperature at which the internal temperature Ti decreases and the liquid return to the inverter compressor 1 starts to occur is defined as the internal reference temperature Til. Note that the internal reference temperature for reducing the rotation speed of the inverter compressor 1 is set lower than the internal reference temperature Til. That is, the inverter compressor 1 is operated at a low rotational speed while the first capillary tube 5 is in use, and the evaporation temperature Te set to a higher value is further increased to prevent liquid return to the compressor from occurring. Can do.

  Further, the second capillary tube 6 was determined so that the liquid return to the inverter compressor 1 did not occur even when the internal temperature Ti was stable, and the cooling capacity was maximized.

  Therefore, in the area A shown in FIG. 2, the first capillary tube 5 having a small flow path resistance is used to ensure a necessary cooling capacity at a high load. Further, in the region C, the second capillary tube 6 having a large flow path resistance is switched, and the liquid return to the inverter compressor 1 is not generated, and a low capacity suitable for stable product temperature is realized.

  Further, in the region B, since it is in an overload state outside the guarantee, if the outside air reference temperature Tol is exceeded, the second capillary tube 6 is immediately switched so that the evaporation temperature Te does not exceed the reference value Tel. However, in the present embodiment, while detecting the evaporation temperature Te, cooling is performed by the first capillary tube 5 as much as possible until the evaporation temperature Te exceeds the reference value Tel, thereby improving the overload performance.

  Next, details of the capillary tube switching control of the present embodiment will be described.

  FIG. 3 is a flowchart showing the operation of the vending machine in the embodiment.

  In FIG. 3, first, if the internal temperature Ti detected by the internal temperature sensor 16 becomes equal to or higher than the compressor start reference temperature Tion while the inverter compressor 1 is stopped, the process proceeds to the next step.

  In the next step, the capillary tube to be used is selected based on the internal temperature Ti. When the internal temperature Ti is lower than the reference temperature Til, the product temperature is stable and the load is low, and the second capillary tube 6 is used. As a result, the evaporation temperature Te can be lowered, and the evaporation temperature Te does not rise abnormally even when the inverter compressor 1 is operated at a low rotational speed. Further, since the refrigerant circulation amount can be reduced, a low cooling capacity suitable for stable operation can be realized.

  Next, when the internal temperature Ti exceeds the reference temperature Til, the capillary tube to be used is selected based on the outside air temperature To. When the outside air temperature To is lower than the reference temperature Tol, that is, at the initial pull-down within the guaranteed range, the first capillary tube 5 is used. Here, the inverter compressor 1 normally rotates at a high speed when the load is high, and the refrigerant circulation amount increases. And by using the 1st capillary tube 5, while being able to make evaporation temperature Te high, a refrigerant | coolant circulation amount can be increased and a cooling capability can be increased.

  On the other hand, when the outside air temperature To exceeds the reference temperature Tol, it is an overload state that is not guaranteed, and the capillary tube to be used is switched based on the evaporation temperature Te. If the evaporation temperature Te does not exceed the reference temperature Tel, the first capillary tube 5 is used. If the evaporation temperature Te exceeds the reference temperature Tel, the second capillary tube 6 is switched. Thereby, even in an overload state, the first capillary tube 5 is used as much as possible to improve the overload performance, and to prevent the evaporation temperature Te from rising abnormally and causing the inverter compressor 1 to fail. it can.

  And the inverter compressor 1 is drive | operated using the capillary tube selected as mentioned above.

  In addition, once it switches to the 2nd capillary tube 6, selection of a capillary tube is not performed until an inverter compressor stops.

  As described above, in the present embodiment, a plurality of capillary tubes having different flow path resistances are arranged in parallel as the throttle mechanism, and the capillary tube is switched according to the internal temperature and the outside air temperature. While sufficiently securing the cooling capacity required at the time of load, the capacity can be reduced at the time of low load, and the cooling system efficiency can be improved by supplying the refrigerant without excess or deficiency to the evaporator, thereby saving energy. In addition, since the capillary tube is used as the throttle mechanism, heat can be exchanged with the suction pipe from the evaporator to the compressor, so that the efficiency of the cooling system can be further improved.

  Further, in the present embodiment, by switching the capillary tube to be used according to the evaporation temperature, an abnormal increase in the evaporation temperature can be prevented, so that the reliability of the compressor can be ensured.

  In the present embodiment, two capillary tubes are used. However, three or more capillary tubes may be used, whereby the cooling capacity can be finely controlled, and the efficiency of the cooling system can be improved.

  In the present embodiment, the internal reference temperature for reducing the rotation speed of the inverter compressor is set lower than the reference temperature for switching the capillary tube, thereby preventing an abnormal increase in the evaporation temperature, and the compressor Since the liquid can be prevented from returning to the compressor, the reliability of the compressor can be ensured.

  As described above, the vending machine according to the present invention can efficiently cool even when there is a large difference in required cooling capacity between a high load and a low load. It can also be applied to applications that need to be made.

Refrigerant circuit diagram of vending machine in Embodiment 1 of the present invention Characteristic diagram showing the operation of the vending machine in the same embodiment in relation to the internal temperature and the outside air temperature Flowchart showing the operation of the vending machine in the same embodiment Conventional refrigerator refrigerant circuit diagram Characteristic diagram showing the range of use of conventional vending machines and refrigerators

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inverter compressor 2 Condenser 5 1st capillary tube 6 2nd capillary tube 7 Evaporator 11 Storage room 12 Machine room 13 Three-way switching valve 14 Cooling system 16 Internal temperature sensor 17 Outside temperature sensor 18 Evaporation temperature sensor

Claims (1)

At least an evaporator installed in a warehouse for storing products, a condenser installed outside a compartment for storing products, an inverter compressor, a throttle mechanism, the inverter compressor, the condenser, and the throttle A cooling system having a cooling system pipe for annularly connecting the mechanism and the evaporator, and a plurality of capillary tubes having different channel resistances are arranged in parallel as the throttling mechanism, and the capillary is controlled by a channel switching means The tube is configured to be switchable, the inside temperature Ti detected by the inside temperature sensor is higher than the reference temperature Til, and the outside air temperature To detected by the outside air temperature sensor is higher than the reference temperature Tol, and When the evaporation temperature Te detected by the evaporation temperature sensor installed in the evaporator is higher than the reference temperature Tel, a cap with a large flow path resistance is used. Vending machine to switch to Richubu.

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