JP2000259934A - Cooling device for automatic vending machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the air suction and leakage burning caused by piping damage in a merchandise storage chamber in a refrigeration medium circuit of an automatic vending machine using hydrocarbon as a refrigerant. SOLUTION: In this cooling device of an automatic vending machine, the operating frequencies of a compressor 4 are controlled so that the pressures of the refrigeration circuit of merchandise storage chambers 1A, 1B and 1C can be always maintained so as to be atmospheric pressures or above, and exhausting devices 14A, 14B and 14C are operated according to the detection of gas detecting devices 13A, 13B and 13C. Thus, even when the refrigeration medium circuits in the merchandise storage chambers, 1A, 1B and 1C are damaged, air is not sucked into the refrigeration medium circuits, thus the hydrocarbon gas is surely leaked to the merchandise storage chambers 1A, 1B and 1C and the leaked hydrocarbon can be directly detected, and prevented from being forcedly exhausted to an atmosphere or from being ignited in the merchandise hosing chambers 1A, 1B and 1C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a vending machine which sells products by cooling or heating a product storage room.

[0002]

2. Description of the Related Art In recent years, the need for a technology for preventing global warming has been urgently required due to an increase in global environmental problems. A conventional cooling device for a hot and cold type vending machine having a multi-compartment storage room capable of switching between a cold mode and a hot mode is disclosed in, for example, JP-A-6-60262. .

[0003] Hereinafter, the above-mentioned conventional vending machine cooling device will be described with reference to the drawings.

FIG. 7 is a block diagram of a conventional vending machine. 1 is the main cabinet of the vending machine and the product storage room 1
A has a cooler 2A for exclusive use in the cooling mode, and a product storage room 1B has a cooler 2B for the cooling mode and the heating mode.
And a heater 3. Coolers 1A and 1B
Are supplied individually from a common compressor 4, the cooler 2 </ b> A is directly connected without a solenoid valve, and the cooler 2 </ b> B is connected to a compressor pipe 6 via a solenoid valve 5. 4 (condenser, expansion valve, etc. are omitted for simplicity).

[0005] Room temperature sensors 7 and 8 each composed of a thermistor are installed in the product storage rooms 1A and 1B, respectively, and a control unit 9 controls the compressor 4 and the solenoid valve 5 on and off based on these temperature signals. Here, an upper limit temperature and a lower limit temperature for ON / OFF control of the coolers 2A and 2B are input and stored in the control unit 9. A switch 10 for switching between cooling and heating is provided in the product storage room 1B. When this switch is turned on, an energizing circuit for the heater 3 is formed.

The operation of the cooling device for a vending machine configured as described above will be described below.

First, when the switch 10 is on the cooling side and the product storage room 1A and the product storage room 1B are set to the cooling mode, the solenoid valve 5 is opened and the compressor 4 is operated. Thereby, the refrigerant is supplied to both the coolers 2A and 2B, and the product storage room 1
Cooling of A and 1B is performed. Then, product storage room 1
When B becomes lower than the lower limit temperature, the solenoid valve 5 is closed, and when the product storage room 1A also becomes lower than the lower limit temperature, the compressor 4 is stopped. In this way, the product storage room 1A and the product storage room 1B are maintained at the cooling temperature in the range from the lower limit temperature to the upper limit temperature.

Next, when the switch 10 is on the heating side, the product storage room 1A is set to cooling, and the product storage room 1B is set to heating,
The supply of the refrigerant to the cooler 2B is stopped by closing the solenoid valve 5. When the heater 3 is energized and reaches the upper limit temperature for heating, the energization is stopped.

Further, as the refrigerant, chlorofluorocarbon (hereinafter, referred to as HCFC) or chlorofluorocarbon (hereinafter, referred to as HFC) is used.

[0010]

However, in the above-mentioned conventional structure, chlorofluorocarbon such as HCFC or HFC is used as a refrigerant, and when leakage from the refrigerant pipe 6 or the like to the outside of the vending machine, particularly to the outside air, the chlorofluorocarbon is not used. Has a high global warming potential, and has environmental issues such as promoting global warming. Therefore, hydrocarbon (hereinafter referred to as H) is used as a refrigerant having a low global warming potential instead of CFC.
Call it C. ) May be used, but many problems remain from the viewpoint of ensuring safety.

First, when HC gas leaks from the refrigerant pipe 6 or the like into the product storage room 1A or the product storage room 1B, the HC gas stays and mixes with air. If the leakage continues, the mixing ratio to air increases. Since the mixture of HC gas and air has flammability in a certain mixing ratio range, the mixing ratio eventually exceeds the lower limit of combustion, and at this time, there is an ignition source such as the heater 3, When the heater 3 is energized, the mixture of air and HC gas may ignite and burn.

Further, when air is sucked from a damaged portion of the refrigerant pipe 6 in the product storage room 1A or the product storage room 1B, the volume of the refrigerant pipe 6 is extremely smaller than that of the product storage room 1A or 1B. However, it takes a short time to reach ignition by some ignition source, and it is difficult to discharge air once it enters the refrigerant pipe 6. Following the inhalation of air, if any sparks such as sparks or static electricity at the electrical contacts of the heater 3 or the like are inhaled from the same damaged part, an explosion phenomenon occurs in the refrigerant pipe 6 and the product storage room 1A or the product storage room with high airtightness. Damage could occur up to 1B.

For this purpose, the product storage room 1A or the product storage room 1
It is conceivable that B is made of a flame-retardant material. However, it is unavoidable that the cost increases, and that the products in the product storage rooms 1A and 1B are exposed to combustion and lose their commercial value. . In addition, a method of providing an ignition source such as a heater outside the product storage room 1A or 1B can be considered. However, it is necessary to separately provide a duct for circulating heated air, which complicates the configuration and is not appropriate. .

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. In a vending machine cooling device using HC having a small influence on global warming as a refrigerant, the present invention relates to a case where the refrigerant leaks from a cooler, piping, etc. It is an object of the present invention to provide a vending machine cooling device which is excellent in safety and has high reliability by preventing ignition even when air is sucked into piping of a storage room.

Further, the above-mentioned conventional configuration is characterized in that the product storage room 1A
And the generation of sparks or static electricity due to opening and closing of the door (not shown) of the product storage room 1B cannot be completely prevented, and the combustion of the refrigerant once leaked into the product storage rooms 1A and 1B cannot be completely prevented. Had.

Further, the product storage room 1A and the product storage room 1B
In order to detect and exhaust HC gas leaked out of the
It is conceivable to install an HC gas detection sensor,
Many parts outside the product storage room 1A and the product storage room 1B are open to the atmosphere, and it is difficult to predict the direction of air flow, the flow rate, and the change in humidity. Therefore, it is necessary to accurately detect the leaked HC gas. Is difficult, and has a drawback that a large number of gas detection sensors need to be installed.

Another object of the present invention is to solve the above-mentioned problems, and to use H as a refrigerant having a small effect on global warming.
It is an object of the present invention to reliably prevent ignition in a cooling device of a vending machine using C, even when HC refrigerant leaks out of a product storage room.

Furthermore, the above-described conventional configuration has a large amount of pressure, especially when the compressor 4 is operated, when a large amount of refrigerant liquid is present in the cooler 2A, and when the refrigerant pipe 6 is damaged. There is a possibility that the HC gas refrigerant leaks and the mixed concentration with air rises to a flash point at once.

Another object of the present invention is to solve the above-mentioned problems. As a refrigerant, H has a small effect on global warming.
In a cooling device of a vending machine using C, when the pressure is high, when a large amount of refrigerant liquid is present in the cooler 2A, and when the refrigerant pipe 6 is damaged, HC refrigerant leaks at once. Instead, it is to prevent the mixed concentration with air from rising to the flash point at once.

[0020]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention provides a compressor capable of converting operating frequency using HC as a refrigerant, a condenser, a throttle device, a heating mode and a cooling mode. A refrigerant circuit is constructed by connecting a cooler provided in each of a plurality of product storage rooms that can be switched to a pipe sequentially in a ring shape, and HC leaked into the product storage room.
A gas detecting means for detecting the pressure, an exhaust device for exhausting air from the product storage chamber to the atmosphere, and controlling the operating frequency of the compressor so as to constantly maintain the pressure of the refrigerant circuit in the product storage chamber at or above atmospheric pressure. And a control means for controlling the exhaust device to operate in response to the detection of the gas detection means.

Thus, the pressure in the refrigerant circuit in the product storage room is always maintained at or above the atmospheric pressure by controlling the frequency of the compressor. Therefore, if the refrigerant circuit is damaged, the refrigerant circuit must be operated. Since the refrigerant leaks from the inside to the outside of the refrigerant circuit toward the large-capacity product storage room, air is sucked into the small-capacity refrigerant circuit from the damaged portion as described above, and then the heater or the like is successively drawn from the same damaged portion. There is no danger of explosion in the refrigerant piping due to inhalation of sparks such as sparks of electric contacts and static electricity, and damage to the product storage room with high airtightness.

Therefore, without leaking air into the refrigerant circuit, the air leaks reliably into the large-volume product storage room, and the leaked HC gas is directly detected and forcibly exhausted to the atmosphere. Even if the amount of HC enclosed in
The effect is obtained that the vending machine can be safely driven by being discharged to the atmosphere through the product storage room without fail.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention uses a compressor capable of converting the operating frequency using HC as a refrigerant, a condenser, a throttle device, a heating mode and a cooling mode. A gas detecting means for detecting HC leaked into the product storage chamber, while forming a refrigerant circuit by sequentially connecting a cooler provided in each of the plurality of product storage chambers that can be switched to a pipe in an annular manner. An exhaust device for exhausting air from the product storage room to the atmosphere, and controlling the operating frequency of the compressor so as to always maintain the pressure of the refrigerant circuit in the product storage room at or above atmospheric pressure, and in response to the detection of the gas detection means, The control means controls the exhaust device to operate.

Thus, the pressure in the refrigerant circuit in the product storage room is always maintained at or above the atmospheric pressure by controlling the frequency of the compressor. Since the refrigerant leaks from the inside to the outside of the refrigerant circuit toward the large-capacity product storage room, air is sucked into the small-capacity refrigerant circuit from the damaged portion as described above, and then the heater or the like is successively drawn from the same damaged portion. There is no danger of explosion in the refrigerant piping due to inhalation of sparks such as sparks of electric contacts and static electricity, and damage to the product storage room with high airtightness.

Therefore, without leaking air into the refrigerant circuit, the gas leaks into the large product storage room without fail, and the leaked HC gas is directly detected and forcibly exhausted to the atmosphere. Even if the amount of enclosed HC is large, it is surely discharged to the atmosphere through the product storage room.

The invention according to claim 2 is provided with a condenser fan and a bypass circuit for bypassing the refrigerant to the condenser to the expansion device, and circulates outside air taken in by the condenser fan outside the commodity storage room. By forming an air path such that the air in the vicinity of the refrigerant circuit outside the product storage room is replaced with the outside air within a predetermined time by discharging the air to the outside air again,
When the amount of condensed matter is reduced, the refrigerant is caused to flow also in the bypass circuit so that the condenser fan is not stopped or the number of revolutions is not greatly reduced.

As a result, even if the refrigerant circuit is broken and the entire amount of the HC gas leaks and fills in the vending machine main body and outside the product storage room, the condenser fan is operated by the condenser fan. Leakage gas can be exhausted to the outside air by the air path formed so that the nearby air replaces the outside air within a certain period of time, so that the lower limit of combustion with air does not reach the lower limit. Does not rise and therefore does not ignite in the presence of an ignition source.

Even when the outside air temperature is reduced or the required amount of condensation is reduced due to a reduced product load, the condenser fan is stopped by flowing the refrigerant through the bypass circuit to reduce the amount of condensation. It is not necessary to reduce the condensing capacity by reducing the fan air volume, and thus the condenser fan can continue to operate without greatly reducing the capacity.In any operating condition, the high-pressure part of the refrigerant circuit is damaged, If the entire amount of HC gas leaks or fills up inside the vending machine and outside the product storage room, no matter where it leaks, the condenser fan exhausts it to the outside air,
Since the lower limit of combustion with air does not reach the lower limit, the concentration of HC gas does not increase until the vicinity of the high pressure part enters the combustion range.
Therefore, even if there is an ignition source, there is no ignition.

Furthermore, there is no need to provide a high-precision sensor for detecting leaks generated outside the product storage room in response to the constantly changing airflow when the condenser fan stops, and to provide a large number of sensors. It will be.

According to the third aspect of the present invention, as the refrigerating machine oil of the compressor, a refrigerating machine oil having high mutual solubility with the refrigerant and a refrigerating machine oil having low mutual solubility with the refrigerant are mixed and used. is there.

Thus, as the pressure in the high pressure section of the refrigerant circuit increases, the amount of the refrigerant gas dissolved in the circulating oil having high mutual solubility increases. As a result, the amount of circulating refrigerant decreases, and the increase in the pressure on the high pressure side eventually stops. Therefore, it is possible to prevent the reliability of the piping from deteriorating due to the increase in pressure, and even if the high-pressure part of the refrigerant circuit is broken, most of the refrigerant circuit melts into highly mutually soluble oil. Moreover, the entire amount of the HC gas does not leak outside the product storage room, and the HC gas is not filled at once. This can prevent the gas from reaching the lower limit of combustion after passing through the detection point of the gas detection sensor in a short time.

Further, since the air is exhausted to the outside air by the condenser fan, the lower limit of combustion with air does not reach the lower limit, so that the concentration of the HC gas does not increase until the vicinity of the high pressure part enters the combustion range. Even if there is a source, it will not ignite. Furthermore, when the liquid refrigerant is easily stored in the low-pressure part of the refrigerant circuit, such as at low outside air temperature, the temperature of the refrigerant and the oil also decreases, so that the amount of the refrigerant dissolved in the oil having high mutual solubility increases and circulates. The amount of refrigerant is reduced, and an appropriate refrigeration capacity is obtained. Further, in any case, lubricating performance is ensured by the oil having low mutual solubility.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vending machine cooling device according to the present invention will be described below with reference to the drawings. In addition,
The same components as those in the related art are denoted by the same reference numerals, and detailed description is omitted.

(Embodiment 1) FIG. 1 is a refrigerant circuit diagram of a cooling device of a vending machine according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a configuration of a control system of the cooling device of the vending machine of the embodiment. FIG. 3 is a flowchart showing the operation of the cooling device of the vending machine of the embodiment.

In FIG. 1, reference numerals 1A, 1B and 1C denote product storage rooms, which are used both in a cooling mode and a heating mode. Further, the volume of the product storage room 1B is the smallest. Reference numerals 5A, 5B, and 5C denote expansion devices, each of which includes a capillary or an electric expansion valve. 6A is a pipe constituting a refrigerant circuit, and the refrigerant flows through the pipe 6A. Hereinafter, the refrigerant circuit refers to the refrigerant pipe 6A, the compressor 4, and the like.
The locations where the refrigerant flows are collectively referred to.

Reference numeral 11 denotes a condenser, which is a compressor 4 and a throttle device 5A.
The pipes are connected between 5B and 5C,
2A, 2B and 2C are coolers, 2A is a throttle device 5A
, 2B are connected to the electric expansion valve 5B, and 2C is connected to the expansion device 5C via the pipe 6A to form a refrigerant circuit. In addition, the coolers 2A, 2B, and 2C are provided in the product storage rooms 1A, 1A, respectively.
B, 1C. Reference numerals 3A, 3B, and 3C denote product heaters for heating the product storage rooms 1A, 1B, and 1C in which the heating mode is selected.

Reference numeral 12 denotes an outside air temperature detecting means for detecting an outside air temperature or an ambient temperature in which the cabinet 1 is placed, and is constituted by a temperature detecting element such as a thermistor. 12A is a control means which controls the expansion device 5 based on the output of the outside air temperature detection means 12 and the like.
A, 5B and 5C are opened and closed. In the refrigerant circuit, a single or mixed refrigerant of HC (for example, isobutane or propane) is sealed as a refrigerant. Reference numerals 13A, 13B, and 13C denote refrigerant gas detecting means which includes a detecting element for detecting HC gas such as propane, isobutane, and ethane.

The gas detecting means 13A, 13B, 13
C is installed in each of the product storage rooms 1A, 1B and 1C, the gas detection means 13A detects gas in the product storage room 1A, the gas detection means 19B detects gas in the product storage room 1B, The gas detector 19C detects gas in the product storage room 1C. 14A, 14B and 14C are exhaust devices,
When activated, air is exhausted from the interior of each of the product storage rooms 1A, 1B, and 1C to the atmosphere outside the product storage room. Exhaust device 14
A, 14B and 14C are composed of, for example, an exhaust duct or an opening / closing damper and a fan (all are not shown).

Reference numeral 15 denotes a pressure detecting means in the pipe, which is provided at a position for detecting the lowest pressure in the product storage chambers 1A, 1B and 1C. Reference numeral 16 denotes a frequency conversion device that changes the operation frequency to change the capacity of the compressor 4. When the generation of gas is detected based on the output results of the gas detection units 13A, 13B, and 13C, the control unit 12A outputs the detected exhaust device 14 of the product storage room 1A or 1B or 1C.
A or 14B, 14C is operated, and the frequency of the compressor 4 is converted by the frequency converter 16 based on the detection result of the pressure detecting means 15.

FIG. 2 is a block diagram showing the configuration of the control system of the cooling device of the vending machine in the embodiment.

In FIG. 2, the control means 12A controls the exhaust devices 14A, 14B, 14C based on the result of comparison between the value of the HC gas concentration output from the gas detection means 13A, 13B, 13C and a value stored in advance. Control the activation and deactivation of Further, the control means 12A is provided with a pressure detecting means 15
The operating frequency of the compressor 4 is changed by the frequency converter 16 based on the comparison result between the value of the pressure in the refrigerant circuit in the product storage room, 1B, and 1C, which is output by the controller, and the value of the atmospheric pressure stored in advance. Convert.

The operation of the above configuration will be described. In this embodiment, the operation of the exhaust device 13B of the product storage room 1B will be described. FIG. 3 is a flowchart showing the operation of the cooling device of the vending machine of the embodiment.

In FIG. 3, while the compressor 4 is operating or stopped, the compressor 4 and the expansion devices 5A, 5B, 5C are in the operating state or the product storage chambers 1A, 1B, 1C are in the cooling mode or the heating mode. Irrespective of this, it is assumed that the hydrocarbon of the refrigerant leaks into the product storage room 1A due to, for example, a part of the refrigerant circuit being damaged.

In step 1, if the value of the refrigerant pressure detected by the pressure detecting means 15 is lower than a predetermined value P1 (for example, a value higher than the atmospheric pressure), the flow shifts to step 2 and the control means 12A
Operates the frequency converter 16 to lower the operating frequency of the compressor 4 and proceeds to step 3. If the value of the refrigerant pressure detected by the pressure detecting means 15 in step 1 is higher than a predetermined value P1 (for example, a value higher than the atmospheric pressure), the process directly proceeds to step 3.

In step 3, if the value of the refrigerant pressure detected by the pressure detecting means 15 is higher than a predetermined value P2 (for example, a value higher than P1), the flow shifts to step 4, and the control means 12A
Operates the frequency converter 16 to increase the operating frequency of the compressor 4 and proceeds to step 5.

In step 3, if the value of the refrigerant pressure detected by the pressure detecting means 15 is equal to or less than a predetermined value P2 (a value higher than the atmospheric pressure), the flow directly proceeds to step 5.

In step 5, if the gas concentration detected by the gas detecting means 13B is higher than the predetermined value T1, the process proceeds to step 6, and the control means 12A operates the exhaust device 13B to exhaust HC in the product storage chamber 1B. Is started, and the process proceeds to step 7. If the gas concentration detected by the gas detecting means 13B is less than the predetermined value T1 in step 5, the process returns to step 1 again.

If it is determined in step 7 that the operating frequency of the compressor 4 is the lowest frequency, the process proceeds to step 8. Step 8
Then, the compressor 4 is stopped, and the routine goes to Step 9. If the operating frequency of the compressor 4 is not the lowest frequency in step 7, the process returns to step 1 as it is.

In step 9, if the gas concentration detected by the gas detecting means 13B is less than the predetermined value T2, step 10
Then, the control means 12A stops the exhaust device 1, terminates the exhaust of the HC in the product storage chamber 1B, and returns to step 1. If the gas concentration detected by the gas detecting means 13B is higher than the predetermined value T2 in step 9, the process returns to step 1 again.
Although the exhaust device 14B has been described here, the same applies when the gas detection unit 13A or 13C detects gas.
Each of the exhaust devices 14A or 14C operates.

As described above, according to the vending machine cooling device of the present embodiment, the compressor 4 capable of converting the operating frequency using HC as the refrigerant, the condenser 11, and the expansion devices 5A, 5A,
B, 5C and coolers 2A, 2B, 2C provided in each of a plurality of product storage chambers 1A, 1B, 1C that can be switched between a heating mode and a cooling mode, are sequentially connected in a ring shape to form a refrigerant circuit. And the product storage room 1A,
Gas detecting means 13A, 13B, 13C for detecting hydrocarbon gas leaking to 1B, 1C, and an exhaust device 14 for exhausting air from the product storage chambers 1A, 1B, 1C to the atmosphere.
A, 14B, 14C and the product storage room 1A, 1B,
The operating frequency of the compressor 4 is controlled so that the pressure of the refrigerant circuit of 1C is always maintained at or above the atmospheric pressure, and the exhaust devices 14A, 14B, and 14C are operated in response to the detection of the gas detection means 13A, 13B, and 13C. And the control means 12 for controlling the product storage room 1
Since the pressure in the refrigerant circuit in A, 1B, and 1C is always maintained at or above the atmospheric pressure by controlling the frequency of the compressor 4, if the refrigerant circuit is damaged, the pressure in the refrigerant circuit must be increased. As the refrigerant leaks out of the refrigerant circuit toward the large-volume product storage chambers 1A, 1B, and 1C, air is sucked into the small-volume refrigerant circuit from the damaged portion as described above, and subsequently, from the same damaged portion. Heaters 3A, 3B, 3
Inhalation of sparks such as sparks of electrical contacts such as C or static electricity causes an explosion phenomenon in the pipe 6A and there is no danger of causing damage to the highly sealed product storage rooms 1A, 1B, and 1C. can get.

Therefore, without leaking air into the refrigerant circuit, the air leaks reliably into the large-volume product storage room, and the leaked HC gas is directly detected and forcibly exhausted to the atmosphere. Even if the amount of enclosed HC is large, it is discharged to the atmosphere through the product storage chambers 1A, 1B, and 1C, and the vending machine can be operated safely.

(Embodiment 2) Hereinafter, a second embodiment of a vending machine cooling device according to the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. FIG. 4 is a refrigerant circuit diagram of a cooling device of a vending machine according to Embodiment 2 of the present invention.

In the figure, reference numeral 17 denotes a condenser fan for promoting the condensation of the condenser 11. 17A transmits the refrigerant discharged from the compressor 4 to the condenser 11 and the expansion devices 5A, 5B, 5
A bypass circuit for bypassing between C and 17B is an on-off valve for controlling the flow of refrigerant into the bypass circuit 17A. Reference numeral 13 denotes a machine room. The machine room 13 includes the compressor 4, the condenser 11, the expansion devices 5A, 5B, and 5C, and the product storage room 1.
A pipe 6A other than the pipes A, 1B, and 1C is housed.

The machine room 18 is provided with an intake port 18A and an exhaust port 18B. 19A, 19B, 19C, 1
9D is an air path forming plate that forms an air path together with the configuration of the machine room 13, and the air path formed by these elements and the air taken in from the intake port 13A by the condenser fan 11A are transferred from the intake port 13A to the condenser 11. The angle, material, length, and the like are adjusted and set so that the refrigerant circuit passes through and circulates through the entire refrigerant circuit, passes through the refrigerant circuit from the condenser 11 to the exhaust port 13B, and is exhausted to the outside air. I have.

Thus, even if the air does not pass through the entire refrigerant circuit, there may be no air stagnation near the refrigerant circuit, and the air in the machine room 13 may be completely replaced with the outside air within a certain period of time.

The operation of the above configuration will be described. In this embodiment, a case will be described in which both the product storage room 1B and the product storage room 1C are set to the cooling mode.

The refrigerant exists in the entire refrigerant circuit irrespective of whether the compressor 4 is operating or stopped, and whether the expansion devices 5A, 5B and 5C are open or closed. Here, when some external force is applied to the refrigerant circuit in the machine room 13 to break the pipe, HC as the refrigerant leaks into the machine room 18. The leaked gas passes through an air path formed by the operating condenser fan 17 and is exhausted to the outside air.

Further, if the outside air temperature decreases,
When the cooling load of B and 2C decreases, the on-off valve 1
Open 7B. Then, a part of the refrigerant discharged from the compressor 4 flows without passing through the condenser 11,
The condensed amount of the refrigerant that has passed through 1 becomes smaller.
Therefore, even if the condenser fan 17 is continuously operated, the amount of condensation does not become too large, the refrigerant liquid is stored in the condenser, and the cooling capacity is not insufficient, and the rotation speed of the condenser fan 17 is extremely reduced. Also, the air in the machine room 13 can always be ventilated while operating at an appropriate pressure and circulation amount without intermittent operation, and the effect that the leaked HC gas does not accumulate can be obtained.

As described above, according to the cooling device for a vending machine of this embodiment, the condenser fan 17 and the bypass circuit 17A for bypassing the refrigerant to the condenser 11 to the expansion device are provided. The outside air taken in is circulated outside the product storage chambers 1A, 1B, and 1C and discharged to the outside air again. In the case of forming a replacement air path and reducing the amount of condensation, the refrigerant is also caused to flow through the bypass circuit 17A so that the condenser fan 17 is not stopped or the rotation speed is not significantly reduced. , The refrigerant circuit is broken and suddenly in the vending machine body and in the product storage room 1
Even when the entire amount of HC gas leaks and fills out of A, 1B, and 1C, the condenser fan 17 allows the product storage room 1A,
Leakage gas can be exhausted to the outside air through an air passage formed so that air near the refrigerant circuit outside the refrigerant circuits 1B and 1C is replaced with the outside air within a predetermined time. The concentration of the HC gas does not increase until the gas enters the range, and therefore, the ignition does not occur even if there is an ignition source.

Even when the outside air temperature is reduced or the required load is reduced due to a reduced product load, the refrigerant is made to flow through the bypass circuit 17A to reduce the amount of condensation.
There is no need to shut down the condenser fan 17 or reduce the fan air flow to reduce the condensation capacity, and therefore, the condenser fan 17 can continue to operate without greatly reducing the capacity. When the high pressure section is damaged and the entire amount of HC gas leaks or fills inside the vending machine main body and outside the product storage chambers 1A, 1B, and 1C, no matter where the HC gas leaks, the outside air is discharged by the condenser fan 17. The HC gas concentration does not reach the lower limit of combustion with air, so the concentration of HC gas does not increase until the vicinity of the high pressure part enters the combustion range, and therefore there is no ignition even if there is an ignition source Such an effect can be obtained.

Further, in response to the constantly changing airflow when the condenser fan 17 is stopped, the product storage room 1A,
There is no need to provide a high-precision HC gas detection sensor or a large number of HC gas detection sensors for completely detecting leaks occurring outside 1B and 1C, and the effect of suppressing an increase in cost can be obtained.

In this embodiment, the product storage rooms 1A, 1B, 1C
In both cases, the cooling mode is used. However, even in the case of another combination such as a heating mode, even if a refrigerant leaks, combustion does not occur and the same effect can be obtained.

(Embodiment 3) Hereinafter, Embodiment 3 of a vending machine cooling device according to the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. FIG. 5 is a refrigerant circuit diagram of a cooling device of a vending machine according to Embodiment 3 of the present invention.

In the figure, reference numeral 20A denotes a refrigerating machine oil having high mutual solubility with the refrigerant sealed in the compressor 4;
It is a refrigerating machine oil that has a lower mutual solubility with the refrigerant. As the refrigerant, for example, isobutane or propane, an ester-based refrigerating machine oil is used for 20A, and a mineral-based refrigerating machine oil is used for 20B. If the temperature of the refrigerating machine oil 20A or the pressure increases, the mutual solubility with the refrigerant increases, the viscosity decreases, and the fluidity increases. On the other hand, the refrigerating machine oil 20B maintains a high viscosity even when the temperature is lowered or the pressure is increased, without a significant change in the mutual solubility with the refrigerant.

The operation of the above configuration will be described.

The case where the product storage room 1B and the product storage room 1C are in the cooling mode will be described as an example. Aperture device 5
When the outside air temperature rises while the compressor 4 is operating with the B and 5C open, the condensation load on the condenser 11 increases, and as a result, the piping from the compressor 4 to the expansion devices 5A, 5B and 5C. The pressure rises and becomes very high. At this time, the refrigerant discharged from the compressor 4 has a high mutual solubility with the refrigerating machine oil 20A having a high mutual solubility. Therefore, a part of the refrigerant circulating in the pipe 6A such as a high-pressure refrigerant liquid condensed in the condenser 11 Dissolves in the refrigerating machine oil 20A having high mutual solubility.
As a result, the refrigerant circulation amount decreases, and the increase in pressure stops.

At this time, among the pipes from the high-pressure side compressor 4 to the expansion devices 5A, 5B and 5C, the expansion device 5 is connected through the outlet of the condenser 11 where the high-pressure refrigerant liquid is present.
When the piping 6A between A, 5B, and 5C is broken, most of the existing refrigerant liquid leaks while being dissolved in the refrigerating machine oil 20A having high mutual solubility with the refrigerant. Then, since it takes time for the refrigerant to evaporate from the leaked refrigerating machine oil 20A, gasification proceeds much more slowly than in the case where the high-pressure refrigerant liquid has leaked. The effect is obtained that the gas concentration does not partially rise to the ignition point within a short period of time.

Further, even if the piping from the compressor 4 to the condenser 11 is broken, the same operation can be performed, so that a large amount of gas does not leak from the broken part in a short time.

When the outside air temperature decreases or the cooling load decreases during the operation of the compressor 4 with the expansion devices 5B and 5C open, the evaporation load of the coolers 2B and 2C decreases, and as a result, the evaporation load decreases. The piping pressure and temperature of the vessels 2B and 2C decrease, and the refrigerant liquid is stored. At this time, the refrigerant liquid that has started to be stored has a high mutual solubility with the refrigerating machine oil 20A having high mutual solubility, and a part of the refrigerant has a high mutual solubility.
Dissolve with OA. As a result, the amount of circulating refrigerant decreases, so that the decrease in pressure stops.

At this time, the product storage rooms 1A, 1B, 1C
When the pipe 6A of the evaporators 2B and 2C in which a large amount of refrigerant liquid is present in the internal refrigerant circuit is broken, most of the existing refrigerant liquid is dissolved in the refrigerating machine oil 20A having high refrigerant mutual solubility. Leak. Then the leaked refrigerator oil 20
Since it takes time for the refrigerant to evaporate from A, the gasification proceeds much more slowly than when the high-pressure refrigerant liquid leaks out.
There is also obtained an effect that the gas concentration does not partially rise to the ignition point within a short time in C.

In any case, since the viscosity of the refrigerating machine oil 20B having a low mutual solubility is maintained, the lubricating performance of the compressor 4 is maintained irrespective of the solubility between the refrigerating machine oil 20A and the refrigerant having a high mutual solubility. it can.

[0072]

As is apparent from the above description, the cooling device for a vending machine according to the first aspect of the present invention uses a HC as a refrigerant and is capable of converting an operating frequency, a condenser, A throttle device and a cooler provided in each of a plurality of product storage chambers that can be switched between a heating mode and a cooling mode are sequentially connected in a ring shape to form a refrigerant circuit,
Gas detection means for detecting HC leaked into the product storage room, and an exhaust device for exhausting air from the product storage room to the atmosphere,
Control means for controlling the operating frequency of the compressor so as to always maintain the pressure of the refrigerant circuit in the product storage chamber at or above atmospheric pressure, and controlling the exhaust device to operate in response to the detection of the gas detection means. With this configuration, the pressure in the refrigerant circuit in the product storage room is constantly maintained at or above atmospheric pressure by controlling the frequency of the compressor. Refrigerant leaks out of the refrigerant circuit toward the large-capacity product storage room from above, so that air is sucked into the small-volume refrigerant circuit from the damaged part as described above, and then the electric power of the heater and the like is continuously supplied from the same damaged part. There is no danger of explosion occurring in the refrigerant piping due to inhalation of any sparks such as sparks or static electricity at the contact points and even damage to the highly sealed product storage room. Therefore, without leaking air into the refrigerant circuit, the leaked HC is surely leaked into the large-volume product storage room,
Since the gas is directly detected and forcibly exhausted to the atmosphere, even if the amount of HC sealed in the refrigerant circuit is large, it is reliably discharged to the atmosphere through the product storage room and the vending machine can be operated safely. .

According to a second aspect of the present invention, there is provided a condenser fan and a bypass circuit for bypassing the refrigerant to the condenser to the expansion device, and circulates outside air taken in by the condenser fan outside the product storage chamber. By forming an air path such that the air in the vicinity of the refrigerant circuit outside the product storage room is replaced with the outside air within a predetermined time by discharging the air to the outside air again,
When the amount of condensation is reduced, the refrigerant circuit is broken by flowing the refrigerant also to the bypass circuit so that the fan for the condenser is not stopped or the number of revolutions is not significantly reduced. Even if the entire amount of HC gas leaks and fills inside the vending machine main body and outside the product storage room, the condenser fan is formed so that the air near the refrigerant circuit outside the product storage room is replaced with outside air within a certain period of time by the condenser fan The leaked gas can be exhausted to the outside air through the open air path,
Since the lower limit of combustion with air does not reach the lower limit, the concentration of HC gas does not increase until the vicinity of the high pressure part enters the combustion range.
Therefore, even if there is an ignition source, there is no ignition.

Even when the outside air temperature is reduced or the required amount of condensation is reduced due to a reduced product load, the condenser fan is stopped by flowing the refrigerant through the bypass circuit to reduce the amount of condensation. There is no need to reduce the condensing capacity by reducing the fan air volume, and thus the condenser fan can continue to operate without greatly reducing the capacity, and under any operating conditions, the high pressure part of the refrigerant circuit is damaged, If the entire amount of hydrocarbon gas leaks or fills up inside the vending machine and outside the product storage room, no matter where it leaks, it will not reach the lower limit of combustion with air because it is exhausted to the outside air by the condenser fan. Therefore, the concentration of the HC gas does not increase until the vicinity of the high-pressure portion enters the combustion range, and therefore, no ignition occurs even if there is an ignition source.

Further, there is no need to provide a high-precision sensor for detecting leaks generated outside the product storage room in response to a constantly changing airflow when the condenser fan stops, and to provide a large number of sensors. The increase in cost can be suppressed.

Furthermore, the temperature of the refrigerant circuit in the high-pressure portion of the compressor or the like tends to be constant due to the constantly stable airflow.
The pressure fluctuation in the refrigerant circuit is also reduced, and the reliability of the compressor is improved.

According to a third aspect of the present invention, as a refrigerating machine oil for a compressor, a refrigerating machine oil having high mutual solubility with a refrigerant and a refrigerating machine oil having low mutual solubility with a refrigerant are mixed and used. As a result, as the pressure of the high-pressure section of the refrigerant circuit increases, the refrigerant gas increases the amount dissolved in the circulating oil having high mutual solubility. As a result, the amount of circulating refrigerant decreases, and the increase in the pressure on the high pressure side eventually stops. Therefore, it is possible to prevent the reliability of the piping from deteriorating due to the increase in pressure, and even if the high-pressure part of the refrigerant circuit is broken, most of the refrigerant circuit melts into highly mutually soluble oil. Moreover, the entire amount of the HC gas does not leak outside the product storage room, and the HC gas is not filled at once.

As a result, it is possible to prevent the gas from passing through the detection point of the gas detection sensor in a short time and reaching the lower limit of combustion. In addition, since the exhaust gas is exhausted to the outside air by the condenser fan, the concentration of HC gas does not increase until the vicinity of the high pressure portion enters the combustion range because the combustion limit with air does not reach the lower limit. It does not ignite.

Further, since the entire amount of the HC gas does not leak suddenly inside the vending machine main body and outside the product storage room, it is possible to obtain an effect that it is not necessary to increase the strength of the piping.

Further, when the liquid refrigerant easily accumulates in the low-pressure portion of the refrigerant circuit, for example, at a low outside air temperature, both the temperature of the refrigerant and the temperature of the oil decrease, so that the amount of the refrigerant dissolved in the oil having high mutual solubility increases. As a result, the amount of circulating refrigerant is reduced, and an appropriate refrigeration capacity is obtained.

Further, in any case, lubricating performance is ensured by oil having low mutual solubility.

Further, since the oil having high mutual solubility makes the flow in the refrigerant circuit smooth, the oil having low mutual solubility has sufficient fluidity, and the refrigerating machine oil is sufficiently returned to the compressor. A sufficient amount of oil can be secured.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a vending machine cooling device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control system of a cooling device of the vending machine of the embodiment.

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

FIG. 4 is a refrigerant circuit diagram of a cooling device of a vending machine according to a second embodiment of the present invention.

FIG. 5 is a refrigerant circuit diagram of a cooling device of a vending machine according to Embodiment 3 of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional vending machine.

[Explanation of symbols]

 1A, 1B, 1C Commodity storage room 2A, 2B, 2C Cooler 3A, 3B Commodity warmer 4 Compressor 5A, 5B, 5C Throttle device 11 Condenser 12A, 12B, 12C Control means 13A, 13B, 13C Gas detection means 14A, 14B, 14C Exhaust device 15 Pressure detecting means 16 Frequency control device 17 Condenser fan 17A Bypass circuit 20A Refrigeration oil with high mutual solubility 20B Refrigeration oil with low mutual solubility

Claims (3)

[Claims] 1. A compressor capable of converting an operating frequency using hydrocarbon as a refrigerant, a condenser, a throttling device, and a plurality of product storage chambers switchable between a heating mode and a cooling mode. And a cooling circuit configured by sequentially connecting annularly connected coolers to form a refrigerant circuit, gas detection means for detecting hydrocarbons leaking into the product storage room, and an exhaust device for exhausting air from the product storage room to the atmosphere,
Control means for controlling the operating frequency of the compressor so as to always maintain the pressure of the refrigerant circuit in the product storage chamber at or above atmospheric pressure, and controlling the exhaust device to operate in response to the detection of the gas detection means. Vending machine cooling device configured. 2. A condenser fan and a bypass circuit for bypassing a refrigerant to the condenser to a throttle device, wherein the outside air taken in by the condenser fan is circulated outside the product storage chamber and discharged to the outside air again. In addition to forming an air path in which air near the refrigerant circuit outside the product storage room is replaced with outside air within a predetermined time, when reducing the amount of condensation, the refrigerant is also allowed to flow through the bypass circuit to perform the condensation. 2. The vending machine cooling device according to claim 1, wherein said cooling device is configured so as not to stop the dexterous fan or to significantly reduce the rotation speed. 3. The automatic vending machine according to claim 1, wherein a refrigerating machine oil having a high mutual solubility with the refrigerant and a refrigerating machine oil having a low mutual solubility with the refrigerant are mixed and used as the refrigerating machine oil of the compressor. Machine cooling system.