JPH11281248A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator having a mechanism for exhausting a refrigerant leaked out of the refrigerator if the refrigerant is leaked therein in the refrigerator using a combustible refrigerant as an operation refrigerator. SOLUTION: The refrigerator comprises a pipe 12 for communicating a lower part of an evaporator with an exterior of a heat insulation case, a communicating pipe opening/closing means 16, and an evaporator temperature detector 14. In this case, if a refrigerant pressure corresponding to a detected temperature of the detector 14 is higher than a saturated temperature of the refrigerant, the means 16 is opened to exhaust a leakage refrigerant from the pipe 12 out of the refrigerator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator using a flammable refrigerant.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of protection of the ozone layer, CFCs containing chlorine atoms which are widely used in refrigeration cycles at present.
The use of refrigerants such as (chlorofluorocarbon) -12 and HCFC (hydrochlorofluorocarbon) -22 has been regulated. As an alternative refrigerant to the refrigeration cycle in which CFC-12 has been used, HFC (hydrofluorocarbon) -134a having no ozone depleting ability and having a close boiling point is currently used. However, since this refrigerant also has a high global warming potential, HC as a next-generation alternative refrigerant has no ozone depleting ability and a very low global warming potential.
(Hydrocarbon) -based refrigerants have been considered. In particular, a refrigerant obtained by mixing propane and isobutane has a boiling point close to that of CFC-12, and a mixed refrigerant containing 40 to 60% by mass of propane has a refrigerating capacity close to that of CFC-12.

[0003]

However, this HC-based refrigerant is flammable, and there is a danger of fire and explosion. In particular, the interior of the refrigerator is a closed space, and even if a small amount of refrigerant leaks, it reaches the flammable lower limit concentration of the HC-based refrigerant.

When a propane single refrigerant or a propane / isobutane mixed refrigerant having a high propane composition ratio is used, the pressure inside the evaporator becomes higher than the atmospheric pressure even during operation of the refrigerator, and In the case of damage, refrigerant leakage occurs in the refrigerator storage.

When a single refrigerant of isobutane or a mixed refrigerant of propane / isobutane having a high isobutane composition ratio is used, the pressure inside the evaporator becomes lower than the atmospheric pressure during the operation of the refrigerator due to physical properties. Even if the evaporator is damaged, it will not leak inside the refrigerator. However,
If the evaporator is heated by a heater or the like during defrosting, or if the refrigerator has not been energized for a long time, such as during transportation, the pressure inside the evaporator will be higher than the atmospheric pressure, and the evaporator will be damaged. In this case, refrigerant leakage occurs in the refrigerator storage.

In order to exhaust the refrigerant leaking from the refrigerator to the outside of the refrigerator, a ventilation mechanism for connecting the inside and the outside of the refrigerator is required. Since the leakage increases and the power consumption of the refrigerator increases, a ventilation mechanism with less heat leakage is required.

[0007] An object of the present invention is to ensure that even if a refrigerant leaks in a refrigerator using a combustible refrigerant, the leaked refrigerant can be exhausted to the outside of the refrigerator to ensure safety.
An object of the present invention is to provide a refrigerator that suppresses heat leakage into a refrigerator and suppresses an increase in power consumption.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an insulating box body having an insulating material inserted between an outer box and an inner box, and at least a compressor, a condenser, and a decompression device. ,
A refrigerator having a refrigeration cycle connected to an evaporator and filled with a flammable refrigerant, wherein the refrigerator has the evaporator in the heat-insulating box, and has a hole opened below the evaporator; It is provided with a communication path for communicating with the outside of the box, and means for opening and closing the communication path. Further, a detecting means for detecting the temperature of the evaporator, and a communication pipe opening / closing means for opening and closing based on a detection result from the detecting means.

[0009] Further, there is provided a detecting means provided in the refrigerator for detecting leakage of the refrigerant, and when the detecting means detects the leakage, the communication pipe opening / closing means is opened.

[0010] Further, a storage portion for storing defrost water generated by defrosting the evaporator is provided, and an opening of the communication pipe on the outside of the heat insulating box is provided above the storage portion. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a cross section of the refrigerator. In FIG. 1, reference numeral 1 denotes a heat insulating box, and front surfaces of the doors 4 and 4 of a freezing compartment 2 and a refrigerator compartment 3 are provided on the front.
It is 5. 6 is a compressor, 7 is a condenser, and 9 is an evaporator. The evaporator 9 is provided inside the heat-insulating box 1. Although not clearly shown in FIG. 1, as shown in FIG. 2, the compressor 6, the condenser 7, the pressure reducing device 8, and the evaporator 9 are connected to form a series of refrigeration cycles. A flammable refrigerant such as propane or isobutane is used as a working medium.

Reference numeral 10 denotes an internal fan, 11 denotes a defrost heater, 1
2 is a communication pipe, 13 is an evaporating dish, 14 is an evaporator temperature detector, 15 is a cool air return passage, 16 is a communication pipe opening / closing means, and 17 is a communication pipe outlet.

The air in the refrigerator compartment is supplied to the refrigerator compartment cool air return passage 1.
5 flows into the evaporator 9 and is cooled, and the fan 10
Is blown to the freezing room 2 or is blown to the refrigerating room 3 through a cool air passage (not shown). Thus, the inside of the freezer compartment 2 and the inside of the refrigerator compartment 3 are cooled.

Exhaust of the refrigerant leaked from the evaporator of the refrigerator configured as described above into the refrigerator will be described below.

First, a first configuration in which a single refrigerant of isobutane and a mixed refrigerant of propane / isobutane having a high isobutane composition ratio are used as a working medium will be described. First, the communication pipe opening / closing means 16 is set to be open when the evaporator temperature Tevp detected by the evaporator temperature detector 14 becomes equal to or higher than a predetermined temperature. Desirably, a temperature T at which the atmospheric pressure equals the saturation pressure of the refrigerant.
At least atm is set to be in the open state. In such a configuration, in a state before the power is supplied, the temperature inside the refrigerator has risen to about the same as the room temperature, and the communication pipe opening / closing means 16 is open. If the evaporator 9 is damaged and the flammable refrigerant leaks, the leaked refrigerant causes the pressure in the refrigerator to be somewhat higher than the atmospheric pressure.
The leaking refrigerant can naturally flow out of the refrigerator from the communication pipe 12. When the cool air sufficiently cooled in the refrigerator circulates during the operation of the refrigerator and the temperature decreases, since the communication pipe opening / closing means 16 is closed, heat leakage from the communication pipe opening / closing means 16 can be suppressed. . That is, the switching temperature of the opening / closing means 16 is set such that the communication pipe opening / closing means 16 is in the closed state during the cooling operation.

Next, the exhaust during the defrosting operation and after the end thereof will be described. The temperature Tevp of the evaporator 9 rises due to the heating of the heater 11 for defrosting, and when Tevp becomes higher than a temperature lower than a preset Tatm, the communication pipe opening / closing means 16 is opened, and the communication pipe 12 opens the inside of the refrigerator. The outside communicates. If the evaporator 9 is damaged and the flammable refrigerant leaks, the leaking refrigerant can naturally flow out of the refrigerator from the communication pipe 12, as in the case before the power is supplied. After the completion of the defrosting, the temperature Tevp of the evaporator 9 decreases, and when the Tevp becomes lower than a preset temperature, the communication pipe opening / closing means 16 is closed, and heat leakage from the communication pipe opening / closing means 16 to the outside of the refrigerator is prevented. Can be suppressed. When the power supply to the refrigerator is stopped, the inside of the refrigerator is not cooled, so that the temperature inside the refrigerator and the evaporator temperature Te are gradually increased.
vp rises, and eventually Tevp becomes equal to or higher than the preset temperature, the communication pipe opening / closing means 16 opens, and the inside and outside of the warehouse communicate with each other through the communication pipe 12. In this state, even if the evaporator 9 is damaged and the flammable refrigerant leaks, the leaking refrigerant can naturally flow out of the refrigerator from the communication pipe 12 as before the energization.

Here, the opening and closing of the communication pipe opening / closing means is performed by using a temperature-sensitive cylinder for the evaporator temperature detector 14 and the communication pipe opening / closing means 16 by using a mechanical damper. The opening and closing of the communication pipe opening and closing means 16 is performed according to the evaporator temperature. The temperature-sensitive cylinder has a refrigerant therein, and the refrigerant changes its volume according to the temperature, and drives the mechanical damper by this change. That is,
The temperature detecting means 14 also serves as a driving means for the communication pipe opening / closing means 16. Of course, even if these detecting means and driving means are provided separately, it is needless to say that the operation and effect of this embodiment do not change.

Although not shown, the communication pipe opening / closing means 16 may be formed using bimetal instead of detecting the evaporator temperature, and a damper that opens and closes in accordance with the temperature around the inlet of the communication pipe 12 may be used. Preferably, as shown in FIG. 3, an opening / closing means 18 is provided in the cold room return passage 15 located below the evaporator 9, and the opening / closing means 18 is provided while the communication pipe opening / closing means 16 is in the open state. By setting the closed state and opening the opening / closing means 18 while the communication pipe opening / closing means is closed, even if isobutane or propane, which is heavier than air, leaks, the cold storage chamber 3 below the evaporator 9 is closed. It is desirable that the exhaust be effectively exhausted from the communication pipe 12 without flowing.

A mechanical damper similar to the communication pipe opening / closing means 16 is used for the cooling room cold air return passage opening / closing means 18.
The evaporator is connected to the evaporator temperature detector 14 by piping, and opens and closes according to the evaporator temperature. Still more preferably, the communication pipe 12
It is desirable to use the communication pipe 12 for drain drainage as a configuration in which the outlet 17 of the drain pipe communicates with the drain evaporating dish 13.

Next, the refrigerator shown in FIG. 4 will be described with reference to the flowchart shown in FIG. In FIG. 4, reference numeral 19 denotes a control device.

First, the communication pipe opening / closing means 16 is initially set.
Is open. If the evaporator 9 is damaged and the flammable refrigerant is leaking, the pressure inside the refrigerator becomes slightly higher than the atmospheric pressure due to the leaking refrigerant, so that the refrigerant leaking from the communication pipe 12 communicating the inside and the outside of the refrigerator. Can naturally flow out of the refrigerator. The temperature detector 14 operates the evaporator 9 at predetermined time intervals t1.
Is detected. The control device 19 is Tevp
And a preset switching temperature. Desirably, the switching temperature is set to a temperature lower than the saturation temperature Tatm of the refrigerant at atmospheric pressure. When the evaporator temperature decreases and Tevp becomes equal to or lower than the preset switching temperature, the control device 19 issues a command to close the communication pipe opening / closing means 16. Then, for a predetermined time t1
After that, Tevp is detected again, and if Tevp is lower than a preset temperature, the communication pipe opening / closing means 16 remains closed.

Here, when the temperature Tevp of the evaporator 9 rises due to the heating of the heater 11 for defrosting and the temperature Tevp becomes higher than the opening / closing switching temperature, the control device 19 issues a command to open the communication pipe opening / closing means 16. Is released, the closed state is released, and the inside and outside of the refrigerator communicate with each other through the communication pipe 12. If the evaporator 9 is damaged and the flammable refrigerant leaks,
Since the pressure inside the refrigerator is slightly higher than the atmospheric pressure due to the leaking refrigerant, the refrigerant leaking from the communication pipe 12 can naturally flow out of the refrigerator. Thereafter, Tevp is detected at every predetermined time t1, and the communication pipe opening / closing means 16 is in an open state during Tevp> opening / closing switching temperature.
When the temperature Tevp of the evaporator 9 decreases and Tevp <opening / closing switching temperature, the control device 19 instructs the communication pipe opening / closing means 16 to close.

When the power supply to the refrigerator is stopped, the communication pipe opening / closing means 16 is returned to the initial state of open.
The control device 19 may set the command. When the refrigerator is not energized for a long time during transportation or the like, since the communication pipe opening / closing means 16 is open, the refrigerant leaks from the communication pipe opening / closing means 16 to the outside as in the case of the above-described defrosting. Can be exhausted.

When the temperature inside the refrigerator is low during the operation of the refrigerator, the communication pipe opening / closing means 16 is closed, so that heat leakage from the communication pipe opening / closing means 16 can be suppressed. As the evaporator temperature detector 14, a defrost end temperature detector may be used. Further, instead of detecting the temperature of the evaporator 9, a configuration may be adopted in which the communication pipe opening / closing means 16 is opened by detecting the energization of the heater 11.

More preferably, as in the first method, an opening / closing means 18 is provided in the cold room return passage 15 located below the evaporator 9, and while the communication pipe opening / closing means 16 is open. The opening / closing means 18 is closed, and while the communication pipe opening / closing means is in the closed state, the opening / closing means 18 is opened, so that the exhaust is effectively exhausted from the communication pipe 12;
As a configuration in which the outlet 17 of the communication pipe 12 communicates with the drain evaporating dish 13, it is desirable to use the communication pipe 12 for drain drainage.

Here, a method of determining the above-described Tatm will be described. The temperature Tatm at which the atmospheric pressure is equal to the saturation pressure of the refrigerant is different between a single refrigerant and a mixed refrigerant. For example, in the case of a single refrigerant, when isobutane as described above is taken as an example, the saturation temperature of the refrigerant at a certain saturation pressure is uniquely determined from physical properties.
For example, when the standard atmospheric pressure of 1 atm is set as the saturation pressure, the saturation temperature of the isobutane single refrigerant is -11.6 ° C. Therefore, it is desirable that the temperature at which the communication pipe opening / closing means 16 is switched from the closed state to the open state be a value of Tatm-11.6 ° C. or less.

Next, in the case of the mixed refrigerant of isobutane and propane, which is a non-azeotropic mixed refrigerant, unlike the case of the single refrigerant, the saturation temperature at a certain saturation pressure is different from that of the single refrigerant due to the physical properties. It cannot be unambiguously defined and takes a value within a certain range depending on the degree of dryness. Isobutane / propane (90
/ 10% by weight), the standard atmospheric pressure is 1 atm.
Is the saturation pressure, the saturation temperature of the saturated steam when the dryness is 0 or 1 is -18.0 ° C. for the former and -14.0 C. for the latter.
It will be 1 ° C. When the dryness takes a value between 0 and 1, the saturation temperature also takes a value between the above two values.

In the above discussion, the standard atmospheric pressure is set to the standard atmospheric pressure of 1 atm. However, the pressure outside the refrigerator differs depending on weather conditions, and the saturation temperature Tatm also fluctuates. Considering the case of a single isobutane refrigerant, the fluctuation amount of the saturation temperature Tatm is about 2 ° C. even in consideration of a change in the atmospheric pressure that may be encountered in a region where the refrigerator is installed. Therefore, the temperature at which the communication pipe opening / closing means 16 is switched from the closed state to the open state is set to a value lower by about 2 ° C. than the value determined based on the standard atmospheric pressure, thereby coping with a change in the atmospheric pressure. it is conceivable that.

As for the temperature at which the communication pipe opening / closing means 16 is switched from the closed state to the open state, means for detecting the atmospheric pressure is provided in the refrigerator, and the controller determines Tatm and Tevp based on the detection result. May be. On the other hand, as a predetermined value before the refrigerator is installed,
It may be incorporated in the control device or may be preset so as to operate mechanically. In this case, the maintenance of the atmospheric pressure detecting means becomes unnecessary, and the cost can be reduced.
More realistic.

As a third method, the refrigerator shown in FIG. 6 will be described with reference to a flowchart 7. In FIG. 6, 19 is a control device, and 20 is a refrigerant leak detector. The communication pipe opening / closing means 16 is opened in an initial state when power is not supplied. If the evaporator 9 is damaged and the flammable refrigerant leaks, the leaked refrigerant will cause the pressure inside the refrigerator to be somewhat higher than the atmospheric pressure, so that the leaked refrigerant will naturally flow out of the refrigerator from the communication pipe 12. be able to.

At the time of energization, the refrigerant leakage detector 20 detects refrigerant leakage into the storage. When there is no refrigerant leakage, the control device 19 closes the communication pipe opening / closing means 16 and can suppress heat leakage from the communication pipe opening / closing means 16. When the refrigerant leak is detected, the control device 19 issues a command to open the communication pipe opening / closing means 16, releases the closed state, and releases the communication pipe 1
The inside and outside of the warehouse communicate with each other through 2. Since the pressure inside the refrigerator is slightly higher than the atmospheric pressure due to the leaking refrigerant, the refrigerant leaking from the communication pipe 12 can naturally flow out of the refrigerator.

When the refrigerator has not been energized for a long time during transportation or the like, the communication pipe opening / closing means 16 is set to be opened, as in the case of the above-described defrosting operation. The refrigerant leaking from 16 can be exhausted to the outside of the refrigerator.

More preferably, as in the first method, an opening / closing means 18 is provided in the cold air return passage 15 located below the evaporator 9 while the communication pipe opening / closing means 16 is open. The opening / closing means 18 is closed, and while the communication pipe opening / closing means is closed, the opening / closing means 18 is opened, so that the communication pipe 12 is effectively exhausted, and the outlet 17 of the communication pipe 12 is closed. It is desirable that the communication pipe 12 be used for drain drainage as a configuration communicating with the drain evaporating dish 13.

When a propane single refrigerant and a propane / isobutane mixed refrigerant having a high propane composition ratio are used as the working medium, the pressure inside the evaporator becomes higher than the atmospheric pressure even during the operation of the refrigerator. With the third method described above, the leaked refrigerant can be exhausted outside the refrigerator, and the heat leakage from the communication pipe opening / closing means 16 can be suppressed.

As a fourth method, the refrigerator shown in FIG. 8 will be described with reference to a flowchart 9. ◆ In FIG.
Denotes a control device, and 20 denotes a refrigerant leak detector. The communication pipe opening / closing means 16 is opened in an initial state when power is not supplied. If the evaporator 9 is damaged and the flammable refrigerant leaks, the leaking refrigerant causes the pressure inside the refrigerator to be somewhat higher than the atmospheric pressure, so that the leakage refrigerant flows out of the refrigerator naturally from the communication pipe 12. be able to.

At the time of energization, the refrigerant leakage detector 20 detects refrigerant leakage into the refrigerator. When there is no refrigerant leakage, the control device 19 closes the communication pipe opening / closing means 16 and can suppress heat leakage from the communication pipe opening / closing means 16. When the refrigerant leak is detected, the control device 19 issues a command to open the communication pipe opening / closing means 16 to release the closed state and release the communication pipe 1.
The inside and outside of the warehouse communicate with each other through 2. Since the pressure inside the refrigerator is slightly higher than the atmospheric pressure due to the leaking refrigerant, the refrigerant leaking from the communication pipe 12 can naturally flow out of the refrigerator.

When the refrigerator has not been energized for a long time, such as during transportation, the communication pipe opening / closing means 16 is open.
As in the case of the defrosting described above, the communication pipe opening / closing means 1
The refrigerant leaking from 6 can be exhausted to the outside of the refrigerator.

More preferably, as in the first method, an opening / closing means 18 is provided in the evaporator suction duct 15 located below the evaporator 9, and the opening / closing means 18 is closed when the communicating pipe opening / closing means 16 is opened. When the communication pipe opening / closing means is closed, the opening / closing means 18 is opened to effectively exhaust air from the communication pipe 12, and the outlet 17 of the communication pipe 12 communicates with the drain evaporating dish 13 so that the communication pipe 12 is drained. It is desirable to use it. When a single propane refrigerant and a propane / isobutane mixed refrigerant having a high propane composition ratio are used as the working medium, the pressure inside the evaporator becomes higher than the atmospheric pressure even during the operation of the refrigerator. According to the fourth method, the leaked refrigerant can be exhausted out of the refrigerator, and the heat leakage from the communication pipe opening / closing means 16 can be suppressed.

The means for solving the above-mentioned problem has been described by taking as an example a refrigerator having a freezer compartment 2 provided in an upper stage.
The same applies to a refrigerator having a configuration in which the freezing room 2 is provided at the lowermost stage as shown in FIG. 10 or a refrigerator having a configuration in which the freezing room 2 is provided at the middle stage as shown in FIG. As shown in FIGS. 10 and 11, the freezing chamber 2 is adjacent to the compressor 6 and the condenser 7 serving as heat sources, so that heat leakage is likely to increase. The effect of reducing leakage is particularly large. Although a control device is not shown in FIG. 10, it goes without saying that a control device for adjusting the opening and closing of the opening / closing means 16 and 18 may be provided as in FIG. 11.

[0040]

According to the present invention, even if a refrigerant leaks in a refrigerator using a combustible refrigerant, the leaked refrigerant can be exhausted to the outside of the refrigerator to ensure safety. Thus, it is possible to provide a refrigerator that suppresses heat leakage into the refrigerator and suppresses an increase in power consumption.

[Brief description of the drawings]

FIG. 1 is a sectional view of a refrigerator according to the present invention.

FIG. 2 is a diagram illustrating a refrigeration cycle of a refrigerator.

FIG. 3 is a sectional view of the refrigerator according to the present invention.

FIG. 4 is a sectional view of the refrigerator according to the present invention.

FIG. 5 is a flowchart showing control according to the present invention.

FIG. 6 is a sectional view of the refrigerator according to the present invention.

FIG. 7 is a flowchart showing control according to the present invention.

FIG. 8 is a sectional view of a refrigerator according to the present invention.

FIG. 9 is a flowchart showing control according to the present invention.

FIG. 10 is a sectional view of a refrigerator according to the present invention.

FIG. 11 is a sectional view of a refrigerator according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulated box, 2 ... Freezer room, 3 ... Refrigerator room, 4 ... Freezer room door, 5 ... Refrigerator room door, 6 ... Compressor, 7 ... Condenser, 8 ... Decompression device, 9 ... Evaporator, 10 ... Internal fan, 11: defrost heater, 12: communication pipe, 13: drain evaporation dish, 14 ...
Evaporator temperature detector, 15 evaporator suction duct, 16 communication pipe opening / closing means, 17 communication pipe outlet, 18 evaporator suction duct opening / closing means, 18 control device, 20 refrigerant leak detector.

Claims (5)

[Claims] 1. An insulating box body having an insulating material inserted between an outer box and an inner box, at least a compressor, a condenser, a decompression device, and an evaporator are connected, and a flammable refrigerant is enclosed. A refrigerating cycle, the refrigerator having the evaporator in the heat insulation box, a hole opened below the evaporator, a communication passage communicating the hole with the outside of the heat insulation box, and a communication passage. A refrigerator having means for opening and closing. 2. A detecting means for detecting a temperature of the evaporator,
2. The refrigerator according to claim 1, wherein the communication pipe opening / closing means is opened / closed based on a detection result from the detection means. 3. The refrigerator according to claim 1, further comprising detecting means provided in the refrigerator for detecting leakage of the refrigerant, wherein the communication pipe opening / closing means opens when the detecting means detects the leakage. 4. An air passage opening / closing means provided below the evaporator for opening / closing an air passage through which air in the warehouse flows, and while the communication pipe opening / closing means is in an open state, the ventilation duct opening / closing means is closed. The refrigerator according to claim 2 or 3, wherein the refrigerator is in a state. 5. A storage section for storing defrost water generated by defrosting the evaporator, wherein an opening of the communication pipe on the outside of the heat insulating box is provided above the storage section. A refrigerator according to any one of claims 1 to 4.