JP2001343181A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of conventional refrigerators that the maximum safety measures must be taken against refrigerant leakage in the case of using inflammable refrigerants because of the following reasons; that flon based refrigerants used in conventional refrigerators and the like are stable in physical properties and can be treated easily, but have a considerably high GWP of about 1,300 even in the case of HFC refrigerants, which do not destroy the ozonosphere, compared with that of about 3 in the case of hydrocarbon series refrigerants, so that they cause the global warming, and that refrigerants such as the hydrocarbon series, however, are highly inflammable refrigerants so that there is the danger of fire or explosion due to an uncontrollable indoor ignition source when the refrigerants leak even if the refrigerator itself is designed to have no ignition source therein. SOLUTION: The refrigerator comprises a refrigerating cycle, in which a refrigerant discharged from a compressor flows through a condenser, a drier, a throttle device, an evaporator and a suction pipe to return to the compressor again, wherein inflammable refrigerants such as hydrocarbon series and the like are used for the refrigerants and the surface temperature of the suction pipe, at the portion thereof exposed in a machine room outside the heat insulating wall of the box, is kept at least at the dew-point temperature of air having a relative humidity of 90% at the outside temperature.

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 refrigerant that does not adversely affect the global environment.

[0002]

2. Description of the Related Art At present, Freon-based refrigerants are used as refrigerants for refrigerators because they have stable physical properties and are easy to handle.

[0003]

The CFC-based refrigerant has stable physical properties and is easy to handle. However, even an HFC refrigerant that does not destroy the ozone layer has a global warming potential GWP of 1300, which is considerably higher than that of a hydrocarbon-based refrigerant of about 3. For this reason, it is considered that this has an adverse effect on global warming, and hydrocarbon refrigerants are used in Germany and Northern Europe. However, a refrigerator using a hydrocarbon-based refrigerant has been conventionally limited to a small structure that does not use a fan with a small amount of enclosed refrigerant.

In the case of a large fan-type refrigerator, a large amount of refrigerant is used. Since refrigerants such as hydrocarbons are highly flammable refrigerants, when a refrigerant leaks from the refrigeration cycle, the ignition source is generated in the refrigerator itself. Even if there is no product specification, there is a risk that a fire or other trouble may occur due to an uncontrolled indoor ignition source. Therefore, in the case of a device that uses a flammable refrigerant,
Maximum safety measures had to be taken to prevent refrigerant leakage.

[0005] Gas leakage may be caused by defects in the manufacturing process, such as poor brazing or broken piping resonance, and corrosion caused by the actual use environment of the purchaser. Since the problems in the manufacturing process can be managed but cannot be controlled even at the customer's environment, there has been a problem that maximum safety measures must be taken against refrigerant leakage, especially against pipe corrosion.

The present invention uses a flammable refrigerant such as a hydrocarbon-based refrigerant which does not adversely affect the global environment as an alternative refrigerant, and pursues safety against corrosion of piping, thereby providing a refrigerator which is friendly to people and the earth. It is intended to be provided. Another object is to obtain a large and reliable refrigerator.

[0007]

According to a first aspect of the present invention, there is provided a refrigerator in which high-temperature refrigerant discharged from a compressor passes through a condenser, a throttle device, and an evaporator, and becomes low-temperature refrigerant to form a suction pipe. A refrigeration cycle that passes through to the compressor again, a flammable refrigerant used for the refrigerant circulating in the refrigeration cycle, and a suction pipe that returns the refrigerant from the evaporator to the compressor. And a heating means for heating the suction pipe so that the temperature of the surface of the suction pipe exposed in the machine room is substantially equal to the refrigerator ambient temperature.

A refrigerator according to a second aspect of the present invention uses a capillary tube as a throttling device, and heat exchanges by soldering or the like between the capillary tube and the suction pipe inside a heat insulating box of a suction pipe for returning refrigerant from an evaporator to a compressor. This heats the suction pipe.

In the refrigerator according to a third aspect of the present invention, a compressor cover is provided on a rear side of a machine room in which a compressor is disposed at a lower rear portion of the heat insulating box, and a vent hole is provided in the compressor cover. By raising the temperature of the machine room while suppressing the temperature rise of the compressor by providing a, the temperature of the exposed part of the machine room is almost changed around the refrigerator by leaving the heat insulation box of the suction pipe that returns the refrigerant from the evaporator to the compressor. The temperature is set to be close to the temperature.

According to a fourth aspect of the present invention, there is provided a refrigerator having a machine room fan disposed in a machine room and circulating air in the machine room, wherein an exposed portion of the suction pipe is arranged in an air passage of the machine room fan. It is.

A refrigerator according to a fifth aspect of the present invention operates a machine room fan or changes a wind speed in accordance with the surface temperature of an exposed portion of a suction pipe.

In a refrigerator according to a sixth aspect of the present invention, the temperature of the surface of the suction pipe is equal to or higher than the dew point temperature at a relative humidity of 90% at the ambient temperature of the refrigerator.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, FIGS. 1 to 7
An embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a sectional view of a fan-type refrigerator, and 1 is a heat insulating material 1-a.
A refrigerator main body having a plurality of storage compartments for covering the surroundings and storing refrigerated items, 2 is a machine room in which the compressor 7 is arranged, 22 is a defrost heater, and 24 is a cold air blower fan in the refrigerator. As shown in FIG. 1, the refrigerator has a structure in which cold air cooled by the evaporator 13 is circulated to each storage room in the refrigerator by a cool air blower fan 24 disposed above the evaporator 13 to cool the refrigerator. It has become. In such a fan-type refrigerator, since a large amount of frost is formed on the evaporator 13, after a certain operation time has elapsed, the defrost heater 22 disposed below the evaporator 13 is energized, and the heat generated by the heater 22 is generated. The evaporator 13 has a structure for removing frost.

FIG. 2 is a block diagram showing a refrigeration cycle. Reference numeral 8 denotes a discharge pipe through which high-temperature and high-pressure refrigerant discharged from a compressor 7 flows to a condenser 9. Reference numeral 10 denotes a dryer for removing moisture in the refrigerant. , 11 is a throttle device which is a capillary tube which is mainly disposed in the heat insulating material and expands the high-temperature and high-pressure liquid refrigerant radiated by the condenser to reduce the pressure, and 20 guides the low-temperature refrigerant from the evaporator 13 to the compressor 7. It is a suction pipe. In the refrigeration cycle of FIG. 2, high-temperature and high-pressure refrigerant is discharged from the compressor 7 and condensed in the condenser 9 via the discharge pipe 8. The refrigerant condensed in the condenser 9 enters the expansion device 11 via the dryer 10 and enters the evaporator 13 while being decompressed, and evaporates. At this time, the air in the refrigerator, which is blown and circulated by the cool air blower fan 24 in the refrigerator, is cooled by the low temperature at which the refrigerant evaporates when passing through the evaporator 13, thereby cooling the air in the refrigerator.

FIG. 3 is an explanatory view of the structure of the machine room. 3 is a machine room fan for blowing air to the compressor, and 4 is a drain pan for collecting water from a drain pipe 5 for guiding defrost water from the evaporator 13.
In FIG. 3, a machine room fan 3 for cooling the compressor 7 is provided, and a drain pan for evaporating defrost water generated by defrosting of the evaporator 13 by heat of the compressor 7 or blowing of the machine room fan 3. And the defrost water from the evaporator 13 to the drain pan 4
And a drain hose 5 for guiding the air to the drain is provided.
As described above, the high-temperature and high-pressure refrigerant that has exited the compressor 7 enters the condenser 9 through the discharge pipe 8 and condenses at, for example, a condensation temperature of 35 ° C. The refrigerant condensed in the condenser 9 enters the expansion device 11 through the dryer 10 and is decompressed.
Enter and evaporate. The low-temperature and low-pressure refrigerant evaporated at the evaporator 13 and having a vaporization temperature of −30 ° C., for example, returns to the compressor 7 through the suction pipe 20. Therefore, the suction pipe 20 through which the refrigerant after leaving the evaporator 13 flows is cooled by the refrigerant, and if the ambient temperature is about 30 ° C., the suction pipe 20 is exposed to the surface of the suction pipe 20-a exposed in the machine room 2. Dew will come.
Although the condenser 9 connected to the discharge pipe 8 is omitted in FIG. 3, the high temperature generated by the condenser 9 is exhausted outside the refrigerator by a fan or the like.

As will be described with reference to FIG. 3 which is a rear view of the machine room 2 provided at the lower rear part of the refrigerator main body 1,
The surface temperature of the interior portion 20-a of the suction chamber 20 of the suction pipe 20 that has entered the machine chamber 2 through the interior of the heat insulator 1-a is determined by heating the suction pipe and dew point at a relative humidity of 90% at the outside air temperature. When the temperature is equal to or higher than the temperature, it is possible to reduce long-term dew on the interior portion 20-a of the suction pipe 20 from the evaporator 13 to the compressor 7 except for the return of the liquid refrigerant at the time of start-up. Since it can also suppress the dissolution of harmful substances in the air into the moisture attached to the pipe surface, a highly safe combustible refrigerant such as a hydrocarbon-based refrigerant that suppresses the risk of gas leakage due to the progress of corrosion was used. A refrigerator or the like can be supplied. Above the dew point temperature at 90% relative humidity, when looking at the monthly average relative humidity in Japan according to the 1996 edition of the science chronology, only a few cities have relative humidity of 90% or more, and the refrigerator itself is continuous. Operation and the suction pipe 20-a
The reason why the state where the dew sticks during the operation is 90% because the insulated door 6 is incompletely closed or the like. This value is individually considered depending on the weather conditions in the target country where the refrigerator is used. As a method of confirming the suction pipe temperature in this example, it is assumed that continuous operation is performed due to misuse. For example, continuous operation is forcibly performed in a room where the outside air temperature is set to about 30 ° C. Measure and confirm the suction pipe temperature in a stable condition.

A structure for heating the suction pipe will be described with reference to FIGS. Reference numeral 18 denotes a capillary tube 11-a, which is a squeezing device 11.
And the suction pipe 20 are made to come into contact with each other in the heat insulating material 1-a to form the heat exchange portion 19. In a refrigerator having a refrigeration cycle shown in FIGS. 4 and 5, a hydrocarbon-based isobutane is used as a refrigerant, and a capillary tube 11-a is used as the expansion device 11.
On the other hand, the high-temperature capillary tube 11-a and the suction tube 20 are heated by the heat exchange unit 19 inside the heat-insulating material 1-a of the heat-insulating box 1, and the refrigerant is transferred from the evaporator 13 to the compressor 7 by the refrigerant. The surface temperature of the portion 20-a inside the machine chamber of the suction pipe 20 for returning pressure is set to be equal to or higher than the dew point temperature at a relative humidity of 90% at the outside air temperature, whereby the surface of the suction pipe 20 can be prevented from being dewed. Is obtained.

As can be seen from the refrigeration cycle shown in FIGS. 1 to 4, the condenser 9 radiates heat to the outside air, which is the ambient temperature of the refrigerator, and has a relationship of "condenser temperature> outside air temperature". Since the capillary inlet temperature is “condenser outlet temperature = dryer temperature = capillary tube inlet temperature”, there is a relationship of “capillary tube inlet temperature> outside air temperature”. On the other hand, since the amount of the refrigerant is set so that the inlet pipe inlet temperature becomes “inlet pipe inlet temperature = evaporator outlet temperature = evaporation temperature”, “−10 ° C. >>> inlet pipe inlet temperature except during defrosting. "It is always cold. The relative humidity is 90%
Since the dew point temperature at the time is approximately at the outside air temperature of -1 to 2 ° C., there is always a relationship of “outside air temperature> dew point temperature at 90% relative humidity”. Therefore, "Capillary inlet temperature> outside temperature> relative humidity 90%
From the relationship of “dew point temperature at the time >>> inlet temperature of the suction pipe”, as shown in FIG.
Is provided with a heat exchanging portion 19 for contacting with a solder or the like to conduct heat, whereby heat is transmitted from the capillary tube 11-a to the suction pipe 20, and the machine chamber inner portion 20 of the suction pipe at the outlet side of the suction pipe.
The temperature of -a is higher than the dew point temperature at a relative humidity of 90%.

FIG. 6 is a side sectional view of the machine room structure, and FIG. 7 is a rear view of the compressor cover. Reference numeral 21 denotes a machine room cover that covers the back opening of the machine room 2 that is opened on the opposite side of the heat insulating door 6, 21 -a denotes a vent provided on the top of the machine room cover 21, and 25 denotes a vibration-proof rubber 26. A base plate 27 for supporting the refrigerator via the inside is a temperature measuring element for measuring the surface temperature of the suction pipe 20-a exposed in the machine room without being covered with the heat insulating material.

As shown in FIG. 3, FIG. 6 and FIG.
A compressor cover 21 is provided on the back side of the machine room 2 in which the compressor 7 is disposed at the lower back of the compressor, and the compressor cover 21 is further provided on the compressor cover 21 as shown in FIG. The warmed air inside the room is the part of the suction pipe inside the machine room 20
Vent 21-a so as to pass through the periphery of -a and to the outside
Is provided, the portion inside the machine chamber of the suction pipe is warmed from the internal air of the machine room which is confined in the machine room by the compressor cover 21 and warmed. Thus, the inside portion 2 of the suction pipe 20 that returns the refrigerant from the evaporator 13 to the compressor 7
The surface temperature of 0-a can be raised while suppressing the temperature rise of the compressor, and in some cases, the heat exchange portion 19 joined by solder which is close to 2 meters together with this structure.
Heat with. Alternatively, as shown in FIG. 3, a machine room fan that sucks in outside air from the outside of the refrigerator and blows the air out of the refrigerator is rotated to promote heat transfer between the pipes of the exposed suction pipe 20-a disposed in the air passage and the air. Alternatively, heat is exhausted from the vent 21-a of the machine room cover. These various measures, alone or in combination, provide an exposed suction tube 20-a.
Pipe temperature near the outside air temperature, that is, when the outside air temperature is 30
If it is set to ゜ C, it can be set to 28.5 ゜ C, which is equal to or higher than the dew point temperature at a relative humidity of 90% at the outside air temperature. The relationship of the temperatures at this time has a relationship of “air temperature inside the machine room> outside air temperature> temperature inside the machine room of the suction pipe> dew point temperature at a relative humidity of 90% >> temperature at the inlet of the suction pipe”. 90 relative humidity
By setting the dew point temperature at or above the%, it is possible to reduce long-term dew on the suction pipe from the evaporator to the compressor except for the return of the liquid refrigerant at the time of start-up, and to adhere to the suction pipe surface. Supplying refrigerators and the like that use highly safe hydrocarbon-based refrigerants and other flammable refrigerants that suppress the risk of gas leakage due to the progress of corrosion because they can also suppress the dissolution of harmful substances in the air into moisture. be able to. Since the amount of heat transfer in the heat exchange section is determined by the relationship between the temperature difference and the heat transfer area, the heat transfer length of the heat exchange section must be determined from the characteristics of the refrigeration cycle so that the surface temperature of the suction pipe is close to the outside air temperature. I just need.

The pipe 20 is generally a copper pipe. Corrosion is basically caused by a battery reaction, and corrosion is more likely to occur in a humid atmosphere. Therefore, the flow of air evaporating from the drain pan and the suction pipe 20-a are restricted. It is desirable that the flow of air passing through the suction pipe 20-a
A structure that does not allow water droplets to adhere to the surface is important. This air flow can be easily divided by the air blow from the machine room fan. When hydrogen sulfide or sulfurous acid gas is present, corrosion is accelerated in a high humidity area, so that a measure against moisture is required. That is, the corrosion that causes gas leakage is a hole contact, and the hole contact is preferentially melted by a battery reaction between the metal active surface and the apparent surface at the hole tip, and corrosion proceeds.
In particular, when the protective function of the surface film is unstable, such as a copper oxide film containing chloride or sulfide, the corrosion is apt to progress, and even if the piping surface is painted, it is caused by scratches during long-term use. In this way, corrosion is a battery reaction, so if the pipe is wet with dew, it will easily progress.In areas where chloride gas and sulfide gas are present, as well as in hot spring areas, even if there is no dew, if the humidity is high, corrosion acceleration will progress. It is important to maintain the surface temperature of the suction pipe at a temperature around the outside air temperature.

In order to reliably prevent dew on the suction pipe in the machine room and to prevent the surrounding humidity, the air temperature around the pipe in the machine room is set to be equal to or higher than the outside air temperature. The surface temperature is measured, and this temperature is several degrees, for example, 25-28 ° C. with respect to the standard outside temperature, for example, 30 ° C. stored in a microcomputer arranged on the control board of the refrigerator.
If the condition is low, keep the machine room fan in operation or keep the fan rotating at a high speed to promote the heat transfer between the air and the piping, thereby reducing the humidity of the piping existing in the ventilation passage of this fan. And dew can be prevented. In addition, the ambient temperature of the refrigerator is directly measured instead of the standard outside air temperature, or information such as temperature measurement data is transmitted to the refrigerator from a device completely different from the refrigerator by superimposing a signal on a power line, and the suction pipe 20 is used. The machine room fan may be controlled in comparison with the surface temperature of -a.

Although a heat exchange section with a capillary tube is provided in the heat insulating material as a heating means of the suction pipe, the suction pipe 20 is partially brought into contact with the discharge pipe 8 or heat is exchanged by being disposed close to the suction pipe 20. Naturally, it is also possible to take measures against moisture by providing a heating means. Even if the temperature of the suction pipe is increased, if the temperature of the entire refrigeration cycle is increased or decreased, it will not greatly affect the characteristics of the refrigeration cycle. Without moisture and dew. In the above description, a machine room fan that sucks in outside air, cools the compressor, and exhausts the air to the outside is used to transfer the heat in the suction pipe and the air in the machine room more.However, if the air around the suction pipe is stirred, It is natural that this air may be stirred by another fan or the like.

[0024]

As described above, according to the present invention, a flammable refrigerant such as a hydrocarbon-based refrigerant which does not adversely affect the global environment is used as a substitute refrigerant, and refrigerant leakage due to pipe corrosion is prevented. Because it can hold down progress,
It becomes very favorable in terms of safety, and a refrigerator and the like that are friendly to people and the earth can be obtained.

Further, according to the present invention, a heat exchange section is provided inside the heat insulating box to enable effective heat transfer.

In addition, the present invention keeps the temperature around the exposed piping at the same level or higher than the outside air while suppressing the rise in the temperature of the compressor, thereby preventing moisture and improving the reliability of the refrigerator.

According to the present invention, dew on the suction pipe can be effectively prevented by air circulating in the machine room.

Further, according to the present invention, the air in the machine room is circulated according to the surface temperature of the exposed portion of the suction pipe, so that a more efficient operation for preventing moisture can be performed.

Further, the present invention can improve the reliability of the refrigerator.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fan-type refrigerator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a refrigeration cycle of the present invention.

FIG. 3 is an explanatory diagram of a machine room structure according to the present invention.

FIG. 4 is a block diagram of a refrigeration cycle having a heat exchange section between a suction pipe and a capillary according to the present invention.

FIG. 5 is an explanatory cross-sectional view of a heat exchange part between the suction pipe and the capillary according to the present invention.

FIG. 6 is a side sectional view of a machine room structure according to the present invention.

FIG. 7 is a rear view of the compressor cover of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Refrigerator main body, 1-a Refrigerator main body insulation material, 2 Machine room, 3 Machine room fan, 4 Drain pan, 5
Drain pipe, 6 insulated door, 7 compressor, 8
Discharge piping, 9 condenser, 10 dryer, 11
Throttle device, 11-a capillary tube, 11-b expansion valve,
12 other capillaries, 13 evaporators, 14 fins,
15 refrigerant pipe, 16 header, 17 refrigerant, 1
8 solder, 19 heat exchange section, 20 suction pipe, 2
0-a Suction pipe inner part of machine room, 21 Compressor cover, 21-a Ventilation opening of compressor cover, 22 Defrost heater, 23 Defrost heater roof, 24 Cooling air blower in cabinet, 25 plate, 26 Prevention Vibration rubber, 27
Temperature measuring element.

Claims (6)

[Claims] 1. A refrigeration cycle in which high-temperature refrigerant discharged from a compressor passes through a condenser, a throttle device, and an evaporator, becomes low-temperature refrigerant, returns to a compressor again through a suction pipe, and circulates through the refrigeration cycle. A flammable refrigerant used for the refrigerant to be cooled, a suction pipe for returning the refrigerant from the evaporator to the compressor, the suction pipe having an exposed portion in the machine room coming out of the heat insulating box, and being exposed in the machine room. A refrigerator comprising: heating means for heating the suction pipe such that the temperature of the surface of the suction pipe is substantially equal to the temperature around the refrigerator. 2. A method of heating a suction pipe by using a capillary tube as a throttle device and exchanging heat by soldering or the like between the capillary tube and the suction pipe inside a heat insulating box of a suction pipe for returning a refrigerant from an evaporator to a compressor. The refrigerator according to claim 1, characterized in that: 3. A compressor cover is provided on a rear side of a machine room in which a compressor is provided at a lower rear portion of the heat insulating box, and a ventilation port is provided on the compressor cover to increase the temperature of the compressor. By raising the temperature inside the machine room while holding down, the temperature of the exposed part of the machine room is brought out to a temperature close to the refrigerator ambient temperature by leaving the heat insulating box of the suction pipe returning the refrigerant from the evaporator to the compressor. The refrigerator according to claim 1, wherein 4. A machine room fan disposed in a machine room and configured to circulate air in the machine room, wherein an exposed portion of the suction pipe is arranged in an air passage of the machine room fan. The refrigerator according to 2 or 3. 5. The refrigerator according to claim 4, wherein the machine room fan is operated or the wind speed is changed according to the surface temperature of the exposed portion of the suction pipe. 6. The refrigerator according to claim 1, wherein the temperature of the surface of the suction pipe is equal to or higher than the dew point temperature at a relative humidity of 90% at the ambient temperature of the refrigerator.