JPH0821666A - Cooling device for slot machine - Google Patents

Abstract

PURPOSE:To effect an optimum control of supplying amount of refrigerant to respective evaporators without causing surplus or shortage in accordance with the superheating degree of the refrigerant in respective evaporators by a method wherein the opening degree of respective expansion valves is controlled in accordance with the detected temperature difference of an inlet temperature sensor and an outlet temperature sensor. CONSTITUTION:A plurality of commodity receiving chambers are provided respectively with evaporators 5a-5c constituting one part of a refrigerating circuit. Expansion valves 4, whose opening degree of valve is variable, are provided in the inlet port side refrigerant tube 6a for respective evaporators 5a-5c while respective evporators 5a-5c are provided with an inlet temperature sensor 14 and an outlet temperature sensor 15 for detecting an inlet temperature and an outlet temperature respectively. The opening degree of respective expansion valves 4 is controlled by a control means 13 in accordance with a detected temperature difference between the inlet temperature sensor 14 and the outlet temperature sensor 15. According to this method, the supplying amount of refrigerant for respective evaporators 5a-5c can be controlled optimally without causing any surplus or shortage in accordance with the superheating degree of refrigerant in respective evaporators 5a-5c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device mounted on a vending machine for canned beverages.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show a conventional cooling device mounted on a vending machine, respectively. With these cooling devices, it is possible to individually cool the three product storage areas that are partitioned by the heat insulation partition walls.
All three product storages are cooled and used in winter, etc.
The sales form can be changed as appropriate, for example, one product storage can be used for cooling and the other two product storage can be used for heating with a heater.

These cooling devices are composed of a refrigeration circuit in which a compressor 2, a condenser 3, a capillary 51, an electromagnetic valve 52, an evaporator 5 and the like are connected to each other by a refrigerant pipe 6 in a closed circuit. Of these, the evaporator 5 is arranged in each of the three product storages. The solenoid valve 52 is
It is of an ON / OFF type and is provided in the inlet side refrigerant pipe 6 of each evaporator 5. In the cooling device shown in FIG. 4, the refrigerant pipe 6 is provided between the solenoid valve 52 and the capillary 51.
It is divided into three by the distributor 8 so that the refrigerant flows evenly through each evaporator 5. On the other hand, in the cooling device shown in FIG. 5, the solenoid valve 5 is attached to the inlet side refrigerant pipe 6 of each evaporator 5.
2 and capillaries 51 are provided so that the refrigerant flows evenly through each evaporator 5.

[0004]

In the cooling device shown in FIG.
Since the total flow rate of the refrigerant passing through the capillary 51 is constant,
For example, under operating conditions where one or two of the three product storages are not used for cooling, an extra refrigerant flows into the evaporator 5 that is being used for cooling, resulting in wasted power consumption,
There is a drawback that operating efficiency is not good. On the other hand, in the cooling device of FIG. 5, since the flow rate of the refrigerant to each of the corresponding evaporators 5 is controlled by each capillary 51, there is no such inconvenience as described above, but the vapor pressure of the refrigerant has decreased in winter or the like. At this time, there is a problem that the capillary 51 becomes a resistance and the flow rate of the refrigerant supplied to the evaporator 5 becomes insufficient.

The present invention has been made in order to solve such a problem, and determines the amount of refrigerant supplied to each evaporator.
Provide a cooling device for a vending machine that can optimally control the excess or deficiency of the refrigerant in each evaporator, thereby improving the cooling operation efficiency and reducing the cost of the device. The purpose is to do.

[0006]

In order to achieve this object, the invention of claim 1 installs an evaporator forming a part of a refrigeration circuit in each of a plurality of product storages to store a plurality of product storages. In a vending machine cooling device that cools the warehouse independently of each other, the expansion valve with variable valve opening provided on the inlet side refrigerant pipe of each evaporator and the inlet temperature and the outlet temperature of each evaporator are An inlet temperature sensor and an outlet temperature sensor for detecting each, and a control means for controlling the valve opening degree of each expansion valve according to the detected temperature difference between the inlet temperature sensor and the outlet temperature sensor are provided. .

Further, the invention according to claim 2 is such that an evaporator forming a part of a refrigeration circuit is installed in each of the plurality of product storages to cool the plurality of product storages independently of each other, and In the cooling device of the vending machine in which one of the product storage boxes is cooled and used in preference to the other product storage box, the valve opening on the inlet side refrigerant pipe of each evaporator is opened. Degree variable expansion valve, outlet temperature sensor to detect the outlet temperature of each evaporator, inlet temperature sensor to detect the inlet temperature of the evaporator installed in one product storage, each outlet temperature sensor and inlet temperature And a control means for controlling the valve opening degree of each expansion valve according to the temperature difference detected by the sensor.

[0008]

According to the cooling device of the first aspect, the inlet temperature sensor and the outlet temperature sensor detect the inlet temperature and the outlet temperature of each evaporator, and the control means controls the difference between the outlet temperature and the inlet temperature, that is, each evaporator. Depending on the degree of superheat of the refrigerant in the vessel,
The valve opening degree of the expansion valve provided in the inlet side refrigerant pipe of each evaporator is controlled. Therefore, the flow rate of the refrigerant supplied to each evaporator can be set to an optimum flow rate without excess or deficiency corresponding to the actual degree of superheat of the refrigerant in each evaporator.

According to the cooling device of the second aspect, the inlet temperature sensor is provided only for the evaporator of the one goods storage used for cooling, detects the inlet temperature of the evaporator, and the outlet temperature sensor is , The outlet temperature of each evaporator is detected. The control means controls the valve opening degree of each expansion valve according to the difference between the outlet temperature and the inlet temperature. That is, the inlet temperature data detected by one inlet temperature sensor is shared for controlling the valve opening degree of each expansion valve. The inlet temperature of the evaporator is hardly affected by the cooling load in the product storage and the performance variation among the evaporators, and there is almost no difference between the evaporators. Therefore,
As described above, by sharing the inlet temperature, the flow rate of the refrigerant supplied to each evaporator can be set to an optimum flow rate without excess or deficiency, and the inlet temperature can be substantially the same as in the cooling device 1 of the claims. The number of sensors can be reduced.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a cooling device for a vending machine according to the first embodiment of the present invention. An automatic vending machine equipped with this cooling device 1 cools or heats products such as canned juice and sells the products, and includes three product storage columns (product storage) (not shown) partitioned by heat insulating partition walls. Have a warehouse). One of these product storage columns is a cooling-only column, which is used for cooling all year round, while the other two are cooling / heating columns, which are used in the summer, for example. For cooling, for warming in winter,
It is appropriately switched and used.

The cooling device 1 includes a compressor 2, a condenser 3, and three electronic expansion valves (expansion valves) 4, 4, 4, and 3.
Each of the evaporators 5 (5a, 5b, 5c) and the like is configured by a cooling circuit in which a refrigerant pipe 6 interconnects each other in a closed circuit.
The refrigerant pipe 6 is divided into three branches by the distributor 8 on the downstream side of the dryer 7 provided downstream of the condenser 3, and the electronic expansion valve 4 and the evaporator 5 are connected in series to each of the three branched refrigerant pipes 6. It is connected. The refrigerant pipe 6 merges on the downstream side of the evaporator 5, and then is connected to the compressor 2 via the check valve 9 and the accumulator 10. Further, between the compressor 2 and the condenser 3, in order to prevent overheating of the compressor 2, a refrigerant pipe 12 with a muffler 11 interposed is circulated.

Of the above components, the evaporator 5 is arranged inside each of the three product storage columns so that the interior of each product storage column can be cooled independently of each other. Further, among the three product storage columns, the one in which the evaporator 5a is arranged is a cooling-only column, and the one in which the evaporators 5b and 5c are arranged is a cooling / heating dual-use column.
In each of these cooling / heating columns, a heating device (not shown) including a heater and a heater fan is provided. Cooling / Cooling of dual-purpose column for heating /
The heating setting is performed by manual operation of a cold / heat changeover switch (not shown).

Each electronic expansion valve 4 is composed of, for example, a stepping motor type expansion valve, is connected to a controller (control means) 13, and the valve is output in accordance with the number of drive pulse signals output from the controller 13. The opening Vo is controlled.

At the inlet side refrigerant pipe 6a and the outlet side refrigerant pipe 6b of each evaporator 5, an inlet temperature sensor 14 composed of a thermistor or the like for detecting the inlet temperature Ti and the outlet temperature To of the evaporator 5 and The outlet temperature sensors 15 are attached, and their detection signals are output to the controller 13. In addition, a similar in-compartment temperature sensor 16 for detecting the in-compartment temperature Tr is provided inside each commodity storage column, and the detection signal thereof is also output to the controller 13.

The controller 13 determines the valve opening degree Vo of the electronic expansion valve 4 in accordance with the signals from the above-mentioned cold / heat changeover switch, the detection signals of the inlet temperature sensor 14, the outlet temperature sensor 15 and the internal temperature sensor 16. Electronic expansion valve 4
A drive pulse signal is output to control the valve opening Vo.

FIG. 2 shows a flow chart of a control program of the cooling device 1 executed by the controller 13. In the following, first, the control operation when all the product storage columns are set for cooling will be described. First, it is determined whether or not the compressor 2 has just been started (step 201).
Each valve opening degree Vo of the electronic expansion valve 4 is set to the initial valve opening degree Voi (step 202).

Next, the inlet temperature Ti of each evaporator 5 detected by the inlet temperature sensor 14 becomes the target inlet temperature Ti1.
(Step 203), and if they are not equal, the valve opening Vo of each electronic expansion valve 4 is controlled so that each inlet temperature Ti becomes equal to the target inlet temperature Ti1 (step 204). ). By this control, variations in accuracy of the electronic expansion valve 4 and the distributor 8 are corrected.

After the steps 203 and 204 are repeated, when the inlet temperatures Ti become equal to the target inlet temperature Ti1, the outlet temperatures To and the inlet temperatures Ti of the evaporators 5 detected by the outlet temperature sensor 15 are detected. Difference To-
Ti, that is, whether or not the degree of superheat of the refrigerant in each evaporator 5 is equal to a predetermined value ΔT (step 20).
5). If not, for each evaporator 5 (To
The valve opening Vo of each electronic expansion valve 4 is controlled so that the (-Ti) value becomes equal to the predetermined value ΔT (step 206). That is, when (To-Ti)> ΔT, the valve opening degree Vo of the corresponding electronic expansion valve 4 is increased to increase the flow rate of the refrigerant, and when (To-Ti) <ΔT, the valve opening degree is increased. The Vo is made smaller to reduce the flow rate of the refrigerant. As a result, the flow rate of the refrigerant supplied to each evaporator 5 can be optimally controlled in accordance with the degree of superheat of each evaporator.

After the above steps 205 and 206 are repeated, when (To-Ti) = ΔT is satisfied for each evaporator 5, the inside temperature Tr of each commodity storage column detected by the inside temperature sensor 17 is Tr. And the target internal temperature Tr1
It is determined whether or not the difference Tr-Tr1 is larger than the predetermined value ΔTr1 (step 207). If it is larger, it is determined that the cooling load on the product storage column has increased, and the valve opening degree Vo of the corresponding electronic expansion valve 4 is controlled to become larger (step 208). As a result, the flow rate of the refrigerant supplied to each evaporator 5 can be controlled to an optimum flow rate according to the change in the cooling load of the product storage column.

After repeating the above steps 207 and 208, (Tr-Tr1) ≤ΔTr1 for each evaporator 5.
When the above condition is satisfied, the inside temperature Tr is equal to the target inside temperature Tr1.
It is determined whether or not is equal to (step 209).
If they are not equal, the process returns to step 207, while
If they are equal, the valve opening degree Vo of the corresponding electronic expansion valve 4 is set to the value 0, and the valve is closed (step 21).
0), this program ends.

When one or two product storage columns are set for cooling, the valve opening degree Vo of only the electronic expansion valve 4 of the product storage column set for cooling is initialized. The valve opening degree Voi is set, and thereafter, the same control as described above is performed.

FIG. 3 shows a cooling device for a vending machine according to the second embodiment of the present invention. This cooling device 31 is different from the cooling device 1 of the first embodiment in that the inlet temperature sensor 14 is attached only to the inflow side refrigerant pipe 6a of the evaporator 5a, and the inlet temperature Ti detected by the inlet temperature sensor 14 is The only difference is that it is shared with the other evaporators 5b and 5c.

As described above, the structure is such that the product storage column in which the evaporator 5a is arranged is a cooling-only column, the other product storage columns are both cooling / heating columns, and the evaporator 5 is used. This is because the inlet temperature of is almost unaffected by the cooling load of the product storage column and the variation in performance among the evaporators, and there is almost no difference between the evaporators 5a, 5b, and 5c. Therefore, the cooling device 31 of the present embodiment
Then, by sharing the inlet temperature sensor 14 attached to the inflow side refrigerant pipe 6a of the evaporator 5a, cooling control substantially the same as that of the cooling device 1 of the first embodiment can be performed, and in comparison with the cooling device 1, By reducing the number of inlet temperature sensors 14, the cost of the cooling device can be reduced.

When the cooling control shown in FIG. 2 is applied to the cooling device 31 of this embodiment, the internal temperature Tr of the cooling-only column has reached the target internal temperature Tr1. When the expansion valve 4 is closed (step 210), the inlet temperature Ti is fixed to a value immediately before the closing of the electronic expansion valve 4 and the valve opening Vo of the other electronic expansion valve 4 is controlled.

As described above, according to the cooling device of this embodiment, the electronic expansion valve 4 is provided in each of the evaporators 5 attached to the plurality of commodity storage columns, and the electronic expansion valve 4 is provided.
The valve opening degree Vo is controlled independently of each other according to the difference between the outlet temperature and the inlet temperature of each evaporator 5, that is, the degree of superheat of the refrigerant. Therefore, the flow rate of the refrigerant to each evaporator 5 can be set to the optimum flow rate corresponding to the change in the cooling load of each product storage column, and the cooling device can be efficiently operated without waste.

Further, in the cooling device of the second embodiment, the inlet temperature sensor 14 provided in the cooling-only column is shared, so that the number of inlet temperature sensors 14 can be reduced and the cost can be reduced.

In this embodiment, a stepping motor type expansion valve is used as the expansion valve whose opening is variable.
It goes without saying that other types of variable opening expansion valves can be used.

[0028]

As described above, the cooling device for a vending machine of the present invention can optimally control the amount of refrigerant supplied to each evaporator according to the degree of superheat of the refrigerant in each evaporator without excess or deficiency. Therefore, the cooling operation efficiency can be improved and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a cooling device according to a first exemplary embodiment of the present invention.

FIG. 2 is a flow chart of a control program for controlling the cooling device of FIG.

FIG. 3 is a diagram showing a configuration of a cooling device according to a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a conventional cooling device.

5 is a diagram showing a conventional cooling device different from that in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling device 4 Electronic expansion valve 5 Evaporator 6a Inlet side refrigerant pipe 13 Controller 14 Inlet temperature sensor 15 Outlet temperature sensor

Claims (2)

[Claims] 1. A cooling device for a vending machine, wherein an evaporator forming a part of a refrigeration circuit is installed in each of a plurality of product storages, and the plurality of product storages are cooled independently of each other. In, an expansion valve having a variable valve opening provided in the inlet side refrigerant pipe of each evaporator, an inlet temperature sensor and an outlet temperature sensor for detecting the inlet temperature and the outlet temperature of each evaporator, and the inlet temperature sensor and A cooling device for a vending machine, comprising: a control unit that controls a valve opening degree of each expansion valve according to a temperature difference detected by an outlet temperature sensor. 2. An evaporator forming a part of a refrigeration circuit is installed in each of the plurality of product storages to cool the plurality of product storages independently of each other, and Among these, in a cooling device of a vending machine in which one product storage is used for cooling prior to the other product storage, an expansion valve with variable valve opening provided on the inlet side refrigerant pipe of each evaporator An outlet temperature sensor for detecting the outlet temperature of each evaporator, an inlet temperature sensor for detecting the inlet temperature of the evaporator installed in the one product storage, and each of the outlet temperature sensor and the inlet temperature sensor A cooling device for a vending machine, comprising: a control unit that controls a valve opening degree of each expansion valve according to a detected temperature difference.