JP4200249B2 - refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a refrigerator when combustible isobutane is used as a refrigerant.
[0002]
[Prior art]
In recent years, environmental problems such as global warming have attracted attention. From such a point of view, the refrigerant is being converted from hydrofluorocarbon to hydrocarbon that is flammable but has very little influence on global warming.
[0003]
Conventionally, as a refrigerator that uses flammable hydrocarbon isobutane as a refrigerant, it is disclosed in P281 to P291 of the 11R-11F commission B1 / 2 proceedings in Belgium in February 1993. Yes.
[0004]
Hereinafter, a refrigerator using conventional isobutane as a refrigerant will be described with reference to the drawings.
[0005]
In FIG. 6, 1 is a refrigerator body, 2 is a heat insulating box, 3 is an inner box made of ABS resin or polystyrene resin, 4 is an outer box made of copper plate, and 5 is made of a heat insulating material made of urethane or the like. . 6 is a door and is provided in the heat insulation box 2. A machine room 7 is installed at the lower back of the main body 1. An evaporator 8 is installed inside the inner box 4. Moreover, the compressor 9 is installed in the machine room 7, and it connects with the condenser 10 and the expansion mechanism 11 in cyclic | annular form sequentially, and comprises a cooling cycle.
[0006]
In this cooling cycle, isobutane 12 is enclosed, and operation is performed by receiving electricity from a power outlet 15. Inside the inner box 4 is installed an internal temperature adjusting means 13 for controlling the stop of the operation of the compressor 9 by the temperature inside the inner box 4. A door switch 14 controls the blinking of the interior lamp 15.
[0007]
About the refrigerator comprised as mentioned above, the operation | movement is demonstrated below. First, when the compressor 9 is operated, the high-temperature and high-pressure isobutane 12 discharged from the compressor 9 is condensed and liquefied by exchanging heat with the outside air in the condenser 10 and flows into the expansion mechanism 11. The isobutane 12 is depressurized by the expansion mechanism 11 and is evaporated by the evaporator 8 to exchange heat with the air inside the inner box 4.
[0008]
The isobutane 12 evaporated here returns to the compressor 9. Further, the compressor 9 is repeatedly operated and stopped under the control of the internal temperature adjusting means 13 as the temperature inside the inner box 4 changes. Here, depending on the internal volume of the evaporator 8, the amount of refrigerant enclosed, the diameter and length of the pipes constituting the cooling cycle, the pressure of the refrigerant in the evaporator 8 is negative during the operation of the compressor 9. However, when stopped, the pressure of the refrigerant in the evaporator 8 becomes equal to or higher than atmospheric pressure.
[0009]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, when the compressor 9 is stopped, the atmospheric pressure of isobutane in the evaporator 8 is higher than the atmospheric pressure, so the evaporator 8 and the expansion mechanism 11 provided inside the inner box 4 or the compression There is a possibility that the flammable isobutane 12 may leak into the inner box 4 of the refrigerator from the connection with the return pipe to the machine 9.
[0010]
There are contact devices such as a door switch 14 and an interior light 15 inside the inner box 4. When the door is opened with the inner box 4 filled with isobutane 12, these contact devices become an ignition source and are flammable. There was a problem that the isobutane 12 ignited and exploded.
[0011]
This invention solves the said conventional subject, and it aims at making isobutane hard to leak inside the refrigerator.
[0012]
[Means for Solving the Problems]
The refrigerator of the present invention is characterized in that the operation of the compressor is stopped only when the pressure of the refrigerant in the evaporator is negative.
[0013]
According to the present invention, it is possible to obtain a refrigerator that can reduce the possibility of igniting and exploding when isobutane leaks inside the refrigerator.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention comprises a heat insulating box having a cooling cycle in which a compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected in an annular shape and isobutane is enclosed as a refrigerant. The refrigerator is characterized in that the operation of the compressor is stopped only when the pressure of the refrigerant in the evaporator is a negative pressure, and the pressure of isobutane in the evaporator is lower than the atmospheric pressure when the compressor is stopped. Therefore, it has the effect | action that isobutane does not leak into the store | warehouse | chamber from the connection part of the evaporator with which the inner side of the inner box of the refrigerator was equipped.
[0015]
The invention described in claim 2 is provided with a sensor for detecting the pressure or temperature of the refrigerant in the evaporator, and the compressor is operated when the sensor detects atmospheric pressure or -15 ° C or more. The refrigerator according to Item 1, wherein when the compressor is stopped, isobutane in the condenser having a temperature higher than that of the evaporator flows into the evaporator and evaporates, so that the temperature and pressure of the refrigerant in the evaporator rise to increase the temperature. When the pressure reaches −15 ° C. and the pressure reaches atmospheric pressure, the isobutane in the evaporator returns to the compressor by operating the compressor by detection of the temperature sensor or pressure sensor, so the pressure of isobutane in the evaporator exceeds the atmospheric pressure. Therefore, isobutane does not leak from the connection part of the evaporator provided inside the inner box of the refrigerator into the cabinet.
[0016]
The invention according to claim 3 is provided with a sensor for detecting the pressure or temperature of the refrigerant in the evaporator and a fan for circulating the cool air in the refrigerator, and when the compressor is stopped, the sensor is at atmospheric pressure or −15 ° C. or higher. 2. The refrigerator according to claim 1, wherein when detected, the fan rotates and the evaporator is cooled by cool air in the cabinet, and the temperature and pressure of the refrigerant in the evaporator rise and the temperature reaches −15 ° C. When the pressure reaches atmospheric pressure, the temperature sensor or the detection of the pressure sensor causes the fan to rotate so that the evaporator is cooled by the cool air in the refrigerator, and the pressure of isobutane in the evaporator increases due to the temperature rise of the evaporator. By reducing the pressure, the pressure of isobutane in the evaporator does not exceed atmospheric pressure, and there is an effect that isobutane does not leak from the connection part of the evaporator provided inside the refrigerator inner box into the refrigerator. That.
[0017]
The invention according to claim 4 is characterized in that a solenoid valve is provided between the evaporator and the condenser, and the solenoid valve is closed before the compressor is stopped to discharge the refrigerant in the evaporator. 2. The refrigerator according to claim 1, wherein the solenoid valve is closed before the compressor is stopped, so that the refrigerant in the evaporator is operated by the operation of the compressor while the refrigerant flow path between the condenser and the evaporator is shut off. Returns to the compressor and the refrigerant in the evaporator is discharged. Therefore, the pressure inside the evaporator does not increase when the compressor is stopped, and it evaporates even if the temperature of the evaporator exceeds 0 ° C due to the defrosting of the evaporator. Since the pressure in the chamber does not increase and does not exceed atmospheric pressure, it has the effect of further improving the prevention of isobutane leakage from the connecting portion of the evaporator provided inside the inner box of the refrigerator.
[0018]
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0019]
(Embodiment 1)
FIG. 1 is a sectional view of a refrigerator according to Embodiment 1 of the present invention. In FIG. 1, 8 is an evaporator and is disposed inside an inner box 4, and 9 is a compressor and is installed in a machine room 7. It is installed, and is connected to the condenser 10 and the expansion mechanism 11 in an annular manner to constitute a cooling cycle, and is installed in the heat insulating box 2.
[0020]
About the refrigerator comprised as mentioned above, the operation | movement is demonstrated below using FIG. First, when the compressor 9 is operated, the high-temperature and high-pressure isobutane 12 discharged from the compressor 9 is condensed and liquefied by exchanging heat with the outside air in the condenser 10 and flows into the expansion mechanism 11. The isobutane 12 is depressurized by the expansion mechanism 11 and is evaporated by the evaporator 8 to exchange heat with the air inside the inner box 4.
[0021]
The isobutane 12 evaporated here returns to the compressor 9. Further, the compressor 9 is repeatedly operated and stopped under the control of the internal temperature adjusting means 13 as the temperature inside the inner box 4 changes.
[0022]
During operation of the compressor 9, the pressure of the isobutane 12 in the evaporator 8 is negative. When the compressor 9 is stopped, isobutane 12 in the condenser 10 having a temperature higher than that of the evaporator 8 flows into the evaporator 8 through the expansion mechanism 11. As the isobutane 12 flowing into the evaporator 8 evaporates, the pressure in the evaporator 8 gradually increases.
[0023]
When the pressure of isobutane 12 in the evaporator 8 reaches atmospheric pressure, the compressor 9 stops operating only when the pressure of the refrigerant in the evaporator 8 is negative, so that the operation of the compressor 9 resumes. . When the compressor 9 starts operation, the isobutane 12 in the evaporator 8 returns to the compressor, and the pressure of the isobutane 12 in the evaporator 8 decreases and does not exceed atmospheric pressure.
[0024]
Therefore, isobutane does not leak from the connection part of the evaporator 8 provided inside the inner box 4 of the refrigerator into the inside of the inner box 4.
[0025]
(Embodiment 2)
FIG. 2 shows a cross-sectional view of a refrigerator according to Embodiment 2 of the present invention. In FIG. 2, 16 is a pressure sensor for detecting the pressure of the refrigerant in the evaporator, and is provided in the inlet pipe of the evaporator 8. It has been.
[0026]
About the refrigerator comprised as mentioned above, the operation | movement is demonstrated below using FIG. First, when the compressor 9 is operated, the high-temperature and high-pressure isobutane 12 discharged from the compressor 9 is condensed and liquefied by exchanging heat with the outside air in the condenser 10 and flows into the expansion mechanism 11. The isobutane 12 is depressurized by the expansion mechanism 11 and is evaporated by the evaporator 8 to exchange heat with the air inside the inner box 4. The isobutane 12 evaporated here returns to the compressor 9.
[0027]
Further, the compressor 9 is repeatedly operated and stopped under the control of the internal temperature adjusting means 13 as the temperature inside the inner box 4 changes. Here, during operation of the compressor 9, the pressure of the isobutane 12 in the evaporator 8 is negative. When the compressor 9 is stopped, isobutane 12 in the condenser 10 having a temperature higher than that of the evaporator 8 flows into the evaporator 8 through the expansion mechanism 11.
[0028]
As the isobutane 12 flowing into the evaporator 8 evaporates, the pressure in the evaporator 8 gradually increases. And when the pressure of the isobutane 12 in the evaporator 8 reaches atmospheric pressure, the compressor 9 restarts operation by detection of the pressure sensor 16. When the compressor 9 starts operation, the isobutane 12 in the evaporator 8 returns to the compressor 9 and the pressure of the isobutane 12 in the evaporator 8 decreases and does not exceed atmospheric pressure.
[0029]
Therefore, isobutane does not leak from the connection part of the evaporator 8 provided inside the inner box 4 of the refrigerator into the inside of the inner box 4.
[0030]
In the above description, the installation location of the pressure sensor is the piping at the inlet of the evaporator, but it may be the piping of the cooling cycle that becomes negative pressure during the operation of the compressor from the outlet of the expansion mechanism to the inlet of the compressor. The installation location is not specified.
[0031]
Moreover, although the case where a pressure sensor is used as the sensor has been described, the same effect can be obtained when the temperature sensor is used to operate the compressor when the detected temperature of the temperature sensor reaches −15 ° C.
[0032]
(Embodiment 3)
3 shows a cross-sectional view of a refrigerator according to Embodiment 3 of the present invention. In FIG. 3, reference numeral 17 denotes a fan, which is provided on the front surface of the evaporator 8.
[0033]
About the refrigerator comprised as mentioned above, the operation | movement is demonstrated below using FIG. The compressor 9 is operated and stopped under the control of the internal temperature adjusting means 13 to adjust the internal temperature of the internal box 4. Here, during operation of the compressor 9, the pressure of the isobutane 12 in the evaporator 8 is negative.
[0034]
Further, when the compressor 9 is stopped, isobutane 12 in the condenser 10 having a temperature higher than that of the evaporator 8 flows into the evaporator 8 through the expansion mechanism 11. The isobutane 12 having a high temperature that has flowed into the evaporator 8 evaporates, whereby the temperature and pressure in the evaporator 8 gradually increase. When the pressure of isobutane 12 in the evaporator 8 reaches atmospheric pressure, the fan 17 is rotated by detection of the pressure sensor 16.
[0035]
At this time, the temperature of the isobutane 12 in the evaporator 8 is −15 ° C., whereas the internal temperature in the inner box 4 is −18 ° C. even if it is high. The cool air circulates and the evaporator 8 is heat-exchanged and cooled, so that the temperature of the isobutane 12 in the evaporator 8 decreases and the pressure of the isobutane 12 in the evaporator 8 decreases.
[0036]
Therefore, isobutane does not leak into the inside of the inner box 4 from the connecting portion of the evaporator 8 provided inside the inner box 4 of the refrigerator.
[0037]
In the above description, the fan 17 is installed on the front surface of the evaporator 8, but the same effect can be obtained by installing the fan 17 on the front surface of the evaporator 8. Also, neither the front direction nor the rear direction is specified for the fan blowing direction.
[0038]
(Embodiment 4)
FIG. 4 shows a cross-sectional view of a refrigerator according to Embodiment 4 of the present invention. In FIG. 4, reference numeral 18 denotes an electromagnetic valve, which is provided in a pipe at the inlet of the evaporator 8. FIG. 5 shows an operation relation diagram of the electromagnetic valve 18 and the compressor 9.
[0039]
The operation will be described below with reference to FIGS. The compressor 9 is operated and stopped under the control of the internal temperature adjusting means 13 to adjust the internal temperature of the internal box 4. Here, as shown in FIG. 5, the electromagnetic valve 18 is controlled to be closed before the compressor 9 stops, and when the electromagnetic valve 18 is closed, the refrigerant flow path between the evaporator 8 and the expansion mechanism 11 is interrupted. Therefore, the isobutane 12 does not flow into the evaporator 8 after the electromagnetic valve 18 is closed.
[0040]
And the isobutane 12 in the evaporator 8 returns to the compressor 9 and is discharged when the compressor 9 is operated. Thereafter, when the compressor 9 stops and the internal temperature inside the inner box 4 rises, the operation of the compressor 9 is resumed by the detection of the internal temperature adjusting means 13. Further, since the solenoid valve 18 is opened before the operation of the compressor 9 is resumed, the refrigerating capacity is not lowered due to the lack of refrigerant when the compressor 9 is started.
[0041]
Therefore, even if the temperature of the evaporator 8 rises due to heat exchange with the inside of the inner box 4 when the compressor 9 is stopped, the isobutane 12 does not exist in the evaporator 8. Does not rise and does not exceed atmospheric pressure. When defrosting by heating the heater of the evaporator 8 is performed, the temperature of the evaporator 8 becomes 0 ° C. or higher, but the pressure in the evaporator 8 does not increase and does not exceed atmospheric pressure.
[0042]
Therefore, it is possible to further improve the prevention of isobutane leakage from the connecting portion of the evaporator 8 provided inside the inner box 4 of the refrigerator to the inside of the inner box 4.
[0043]
In the above description, the solenoid valve 18 is provided in the piping at the inlet of the evaporator 8, but may be provided in the piping at the outlet of the condenser 10 outside the inner box 4. In order to reduce the amount of isobutane liquid flowing into the evaporator 8, a location close to the evaporator 8 is preferable. Considering the effectiveness of the internal volume and productivity, a location close to the condenser 10 is preferable.
[0044]
As described above, according to Embodiment 3 of the present invention, the possibility that isobutane ignites and explodes due to leakage inside the refrigerator can be further reduced.
[0045]
【The invention's effect】
As described above, according to the present invention, since the operation of the compressor is stopped only when the pressure of the refrigerant in the evaporator is negative, the pressure of isobutane in the evaporator does not exceed atmospheric pressure. The isobutane is less likely to leak from the connection part of the evaporator provided inside the inside of the box to the inside of the inner box.
[Brief description of the drawings]
1 is a sectional view of a refrigerator according to a first embodiment of the present invention. FIG. 2 is a sectional view of a refrigerator according to a second embodiment of the present invention. FIG. 3 is a sectional view of a refrigerator according to a third embodiment of the present invention. 4 is a cross-sectional view of a refrigerator according to a fourth embodiment of the present invention. FIG. 5 is an operation relation diagram of a solenoid valve and a compressor of the refrigerator according to a fourth embodiment of the present invention. Explanation】
2 heat insulation box 8 evaporator 9 compressor 10 condenser 11 expansion mechanism 12 isobutane 16 pressure sensor 17 fan 18 solenoid valve

Claims (4)

A compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected in an annular manner to form a heat insulating box having a cooling cycle in which isobutane is sealed as a refrigerant, and the refrigerant pressure in the evaporator is negative. A refrigerator characterized by stopping the operation of the compressor only when. 2. The refrigerator according to claim 1, wherein a sensor for detecting the pressure or temperature of the refrigerant in the evaporator is provided, and the compressor is operated when the sensor detects atmospheric pressure or -15 [deg.] C. or higher. It has a sensor that detects the pressure or temperature of the refrigerant in the evaporator and a fan that circulates cool air in the refrigerator. When the sensor detects atmospheric pressure or -15 ° C or higher when the compressor is stopped, the fan rotates. The refrigerator according to claim 1, wherein the evaporator is cooled by cold air in a refrigerator. 2. The refrigerator according to claim 1, wherein an electromagnetic valve is provided between the evaporator and the condenser, and the refrigerant in the evaporator is discharged by closing the electromagnetic valve before stopping the compressor.

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