JP2001133127A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a combustible refrigerant is possibly fired when defrost operation is performed under an environment where the combustible refrigerant leaked to a part communicating with the inside of a refrigerator because the temperature of a heater wire constituting a defrost means exceeds the firing point of the combustible refrigerant. SOLUTION: In a defrost means comprising a heater wire 23 of metallic resistor wound spirally, a glass tube 22 covering the heater wire 23, and a reflector 16 placed on the glass tube 22, the reflector 16 has end parts directing downward and the lower end at the end part of the reflector 16 is not lower than the upper end on the outer circumference of the glass tube 22. Temperature rise of the heater wire 23 is suppressed by enhancing heat dissipation from the heater wire 23 to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator having a defrosting means for an evaporator.

[0002]

2. Description of the Related Art In recent years, a refrigerator having a defrosting means for an evaporator is disclosed in Japanese Patent Application Laid-Open No. 8-54172.

Hereinafter, the conventional refrigerator will be described with reference to the drawings.

FIG. 14 is a schematic longitudinal sectional view of a conventionally proposed refrigerator. In FIG. 14, 1 is a refrigerator main body,
2 is a freezing room inside the refrigerator main body 1, 3 is a refrigerator room inside the refrigerator main body 1, 4 is a freezing room door, 5 is a refrigerator room door,
6 is a partition wall that separates the freezer compartment 2 from the refrigerator compartment 3, and 7 is the freezer compartment 2
A refrigerator inlet for sucking air in the refrigerator compartment; a refrigerator inlet for sucking air in the refrigerator compartment; a discharge outlet for discharging cool air;
10 is an evaporator, 11 is a fan for circulating cool air, 12 is an evaporator partition wall separating the evaporator 10 and the freezing room 2, 13 is a tub, 14 is a drain port, and 15 is a spirally wound metal resistor. A defrosting tube heater 16 having a heater wire covered with a glass tube prevents evaporation noise generated when defrost water directly drops on and contacts the defrosting tube heater 15, and is emitted by the defrosting heater. A metal upper reflector 17 that reflects the heat generated is a metal lower reflector installed between the tub 13 and the defrosting tube heater 15.

Next, the operation will be described. When cooling the freezer compartment 2 or the refrigerator compartment 3, the refrigerant flows through the evaporator 10 to cool the evaporator 10. Fan 1 in the same way
By the operation of 1, the cold air heat-exchanged by the evaporator 10 is sent into the freezing room 2 through the discharge port 9, and
Through the communication port (not shown) to the refrigerator compartment 3. Then, the cool air which has been sent to the freezing room 2 and the refrigerator room 3 and heated up returns through the freezing room suction port 7 and the refrigerating room suction port 8 and is again heat-exchanged by the evaporator 10 to the freezing room 2 and the refrigerator room 3. Sent in.

Here, the air that exchanges heat with the evaporator 10 is:
An evaporator having a lower temperature than the air because it contains moisture at room temperature and outside air that enters by opening and closing the freezer compartment door 4 and the refrigerator compartment door 5 and moisture evaporated from food stored in the freezer compartment 2 and the refrigerator compartment 3. When heat is exchanged at 10, moisture in the air becomes frost and forms frost on the evaporator 10 and its peripheral parts.
When a refrigerator is used in real life, this operation is repeated, and the amount of frost increases gradually, resulting in an evaporator 10.
Heat transfer between the surface and the air that exchanges heat is hindered, and the amount of air circulating from the evaporator 10 to the freezing compartment 2 and the refrigerating compartment 3 decreases, resulting in insufficient cooling.

Therefore, before the cooling becomes insufficient, the heater wire of the defrosting tube heater 15 is energized to heat the heater wire to a high temperature. The amount of heat generated from the heater wire is transported to the evaporator 10 and its peripheral parts by utilizing heat transfer phenomena such as heat conduction, convection and radiation, and melts attached frost. At this time, part of the heat rays radiated to the upper reflector 16 and the lower reflector 17 as radiant heat are reflected by the defrosting tube heater 15, and other radiant heat is reflected toward the evaporator 10 and other peripheral parts. You. Thereby, the frost that has arrived near the evaporator 10, the tub 13, and the drain 14 is melted into water. Further, the defrost water thus melted falls into the tub 13 avoiding the defrosting tube heater 15 by the upper reflector 16 or directly falls into the tub 13 and is drained out of the refrigerator through the drain port 14. .

[0008]

However, in the conventional configuration, the heat generated by the defrosting tube heater 15 and the radiation thereof generally cause the defrosting tube heater 15, the upper reflector 16 and the lower reflector 17 to be in close proximity. Although the air is heated and an updraft is generated by natural convection, the upper reflector 16
However, the convective heat transfer from the air near the defrosting tube heater 15 is not good.

As a result, heat radiation from the defrosting tube heater 15 to the surrounding air is poor, and the temperature of the surface of the nichrome wire and the surface of the glass tube becomes extremely high, easily exceeding the ignition point temperature of the flammable refrigerant. From this, when a flammable refrigerant is used as the refrigerant, if the flammable refrigerant leaks from a pipe exposed to a portion communicating with the evaporator 10 or the inside of the refrigerator,
There is a problem that there is a possibility of ignition due to energization of the defrosting tube heater 15.

The present invention has been made in view of the above problems, and provides a refrigerator capable of suppressing the possibility of ignition by the flammable refrigerant even when the flammable refrigerant leaks into the installation atmosphere of the defrosting means and the defrosting is performed. The purpose is to do.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 has a function of connecting a compressor, a condenser, a pressure reducing mechanism, and an evaporator in a flammable manner. A refrigeration cycle containing a refrigerant, a cooling chamber in which the evaporator is housed, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means has a spiral shape. A heater wire composed of a metal resistor wound around, a glass tube covering the heater wire, and a reflector disposed on the glass tube upper portion, the reflector end portion is formed downward and the It is characterized in that the lower end of the end of the reflector is shaped to be higher than the upper end of the outer periphery of the glass tube.

According to a second aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled therein, and a cooling chamber containing the evaporator. A defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means covers a heater wire made of a spirally wound metal resistor and the heater wire It comprises a glass tube and a reflector disposed above the glass tube, and has a feature that a vent is provided in the reflector.

A third aspect of the present invention is characterized in that, in the second aspect of the present invention, the vent is formed such that the opening width of the vent is equal to or larger than the radius of the glass tube.

According to a fourth aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled therein, and a cooling chamber containing the evaporator. A defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means covers a heater wire made of a spirally wound metal resistor and the heater wire It is constituted by a glass tube and a reflection plate provided on the upper part of the glass tube, and is characterized in that the reflection plate is disposed so as to be inclined in the circumferential direction of the glass tube.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the reflection plate is disposed so as to be inclined toward a cool air return air passage opening provided at a lower portion of the cooling chamber. It has the features.

According to a sixth aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is charged, and a cooling chamber containing the evaporator. A defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means covers a heater wire made of a spirally wound metal resistor and the heater wire It comprises a glass tube and a reflector disposed above the glass tube, and is characterized in that the width of the reflector is shaped to be no more than twice the diameter of the glass tube.

According to a seventh aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled therein, and a cooling chamber containing the evaporator. A defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means covers a heater wire made of a spirally wound metal resistor and the heater wire A glass tube, comprising a reflector disposed on the glass tube upper portion, wherein the reflector end is formed downward and the lower end height of the reflector end is greater than or equal to the outer peripheral upper end height of the glass tube It is formed so as to be, and provided with a vent in the reflection plate, and disposed so that the reflection plate is inclined toward the cold air return air passage opening side provided in the lower part of the cooling chamber, and The width of the reflector is not more than twice the diameter of the glass tube. And a molded features as.

According to the first to seventh aspects of the present invention, even if the flammable refrigerant leaks into the atmosphere where the defrost means is installed, the flammable refrigerant is removed. Can suppress the possibility of ignition.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a refrigeration cycle in which a compressor, a condenser, a pressure reducing mechanism, and an evaporator are functionally connected, and a flammable refrigerant is filled therein; And a defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor. And a glass tube that covers the heater wire, and a reflector disposed on the glass tube, wherein the reflector end is formed downward and the lower end height of the reflector end is lower than the glass height. By having a feature formed so as to be equal to or higher than the outer peripheral upper end height of the tube, it is possible to prevent the defrosting water from dropping onto the glass tube and reflect the heat released from the heater wire toward the lower part of the cooling chamber, thereby radiating heat. Melts the frost deposited at the bottom of the cooling chamber While maintaining the function of, the temperature of the retained high-temperature air can be reduced by increasing the natural convection effect in which the high-temperature air retained between the glass tube and the reflector convects upward and transports heat upward, As a result, the amount of heat radiation from the heater wire can be increased and the heater wire itself can be maintained at a low temperature. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. Therefore, even if defrosting is performed in an environment where the flammable refrigerant leaks from the refrigeration cycle into the refrigerator, the possibility of ignition can be suppressed.

According to a second aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled therein, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire A glass tube that covers the glass tube, and a reflector provided on the upper portion of the glass tube, and having a feature in which a vent is provided in the reflector, to prevent defrosting water from dropping onto the glass tube. The heat emitted from the heater wire is reflected toward the lower part of the cooling chamber to maintain the function of melting the frost deposited on the lower part of the cooling chamber by radiant heat, and the high-temperature air staying between the glass tube and the reflecting plate is directly heated. Pass through the vent Thermal Te and for transporting upwardly the can be reduced temperature dwell hot air, can result amount of heat radiated from the heater wire to maintain the heater wire itself to a low temperature increase. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. Therefore, even if defrosting is performed in an environment where the flammable refrigerant leaks from the refrigeration cycle into the refrigerator, the possibility of ignition can be suppressed.

The invention according to claim 3 is the same as the invention according to claim 2.
In the invention described in the above, by providing a feature that the opening width of the vent is formed so as to be equal to or larger than the radius of the glass tube, prevention of dripping of defrost water onto the glass tube and heat released from the heater wire. While maintaining the function of reflecting the frost accumulated in the lower part of the cooling chamber by reflecting the radiant heat in the lower part of the cooling chamber, the natural convection formed via the vent can be smoothly and stably developed. The effect of reducing the temperature rise of the heater wire can be increased. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason,
Even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

According to a fourth aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled therein, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire A glass tube that covers the glass tube, and a reflector provided above the glass tube, wherein the reflector is provided so as to be inclined in a circumferential direction of the glass tube. The natural convection due to the high-temperature air in the vicinity of the defrosting means is smoothly developed along the inclination of the reflection plate while maintaining the effect of preventing the defrosting water from dropping onto the pipe and the effect of reflecting the radiant heat emitted from the heater wire. The heater wire It is possible to suppress the Atsushi Nobori. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced.
For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

The invention described in claim 5 is the same as the invention described in claim 4.
In the invention described in the above, by providing a feature that the reflection plate is arranged so as to be inclined toward the cold air return air passage opening side provided in the lower part of the cooling chamber, by the high temperature air near the defrosting means By smoothly joining the cool air flowing from the cool air return airflow opening to the natural convection, the convective heat transfer effect can be improved, and the temperature rise of the heater wire can be further suppressed. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

According to a sixth aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected to each other and a flammable refrigerant is filled therein, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire A glass tube that covers the glass tube, and a reflector provided on the upper portion of the glass tube, wherein the width of the reflector is shaped to be equal to or less than twice the diameter of the glass tube. Natural convection by high-temperature air near the defrosting means can be smoothly and stably developed while maintaining the effect of preventing defrosting water from dropping onto the glass tube and the effect of reflecting radiant heat emitted from the heater wire. Heating of the heater wire It can be suppressed. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

According to a seventh aspect of the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire And a reflector disposed above the glass tube, wherein the end of the reflector is shaped downward and the lower end of the end of the reflector is lower than the outer periphery of the glass tube. And a ventilation hole is provided in the reflection plate, and the reflection plate is disposed so as to incline toward a cool air return air passage opening side provided in a lower portion of the cooling chamber. And the width of the reflector is at least twice the diameter of the glass tube. By having a feature that is shaped so that the natural convection that rises past the end of the reflector is smoothed, and the reflector is provided with the vent and develops directly upward from the glass tube. Forming natural convection, and making the lower end height on the opposite side of the cold air return air passage opening portion higher than the lower end height of the reflector end provided on the cold air return air passage opening side, and reflecting the light. By inclining the plate approximately toward the cold air return air passage opening side, the cold air in the refrigerator flowing from the cold air return air passage opening is smoothly taken into the ascending airflow, and the width of the reflection plate is equal to the diameter of the glass tube. By configuring so as to be twice or less, natural convection can be smoothly and stably developed.

As a result, the air temperature in the vicinity of the defrosting means is reduced by the convective heat transfer, the heat radiation performance from the heater wire is improved, and the temperature rise of the heater wire itself can be largely suppressed. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

Embodiment 1 Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a refrigeration system diagram of a refrigerator according to the first embodiment of the present invention, FIG. 2 is an enlarged sectional view of the defrosting means 18, FIG. 3 is a sectional view of the defrosting means 18 shown in FIG. FIG. 9 is a characteristic diagram illustrating a relationship between the lowermost end heights of both ends of the reflection plate 16 and a temperature rise of the heater wire 23.

As shown in FIG. 1, reference numeral 18 denotes defrosting means for defrosting frost adhering to the evaporator 10, and 19 denotes a compressor, 2
0 is a condenser, 21 is a decompression mechanism constituted by a capillary tube, and the compressor 19, the condenser 20, the decompression mechanism 21, and the evaporator 10 are functionally connected in a ring form as a refrigeration cycle, A flammable natural refrigerant is sealed in the refrigeration cycle.

Further, as shown in FIG.
Is composed of a glass tube 22, a heater wire 23 formed of a spirally formed metal resistor, a cap 24 for preventing defrost water from entering the inside of the glass tube 22, and a defrost water dripping onto the glass tube. And a reflection plate 16 that reflects the heat generated from the heater wire 23.

Further, as shown in FIG. 3, both end portions of the reflecting plate 16 are formed so as to face downward, and the height of the lower ends of both ends of the reflecting plate is higher than the height of the outer peripheral upper end of the glass tube 22. .

With respect to the refrigerator configured as described above,
The operation will be described below.

The operation of the compressor 19 causes the flammable refrigerant sealed in the refrigeration cycle to circulate in the direction of the arrow in FIG. 1 to cool the evaporator 10. At the same time, the fan 11 operates, and the cool air exchanged by the evaporator 10 is discharged into the refrigerator. The cool air discharged to the outside of the refrigerator is heated in the refrigerator, returns to the vicinity of the evaporator 10, exchanges heat again, and is discharged into the refrigerator. Here, the air that exchanges heat with the evaporator 10 contains the moisture of room temperature outside air that enters by opening and closing the refrigerator door and the moisture evaporated from the food stored in the refrigerator, so that the evaporation is lower in temperature than the air. When heat is exchanged in the vessel 10, the moisture in the air becomes frost and forms frost, and the amount of frost increases gradually. As a result, the heat transfer between the surface of the evaporator 10 and the air that exchanges heat is hindered. In addition, the amount of air circulating from the evaporator 10 into the storage decreases, resulting in insufficient cooling. Therefore, after an arbitrary operating time of the compressor 19 has passed, the defrosting means 18 is energized to cause the heater wire 23 to generate heat. The defrosting of the evaporator 10 and its peripheral parts is performed by the heat generation and heat radiation of the heater wire 23, the completion of defrosting is detected by detecting means (not shown), and the defrosting means is stopped. Periodically prevent insufficient cooling.

The amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a temperature rise of the heater wire itself and external heat radiation through the air and the glass tube 22. The convection and radiation phenomena are used for the defrosting operation, and the temperature of the air near the defrosting means 18 rises due to the heat transfer from the reflector 16 and the glass tube 22 which has become high temperature due to the heat radiation from the heater wire 23, and natural convection occurs. Causes an updraft. At this time, generally, of the effect of preventing the defrosted water from dropping onto the glass tube 22 of the reflector 16 and the effect of reflecting the radiant heat emitted from the heater wire 23, the former, especially, the effect of preventing the defrosted water from being dropped is increased. Therefore, the reflection plate 16
Are configured to be lower than the height of the outer peripheral top of the glass tube 22, but if the height of the lower ends of both ends of the reflector 16 is low, natural convection is impeded and heat transport by convection is hindered. The temperature in the vicinity of the means 18 becomes extremely high, and the heat radiation performance from the heater wire 23 is deteriorated. As a result, the temperatures of the heater wire 23 and the glass tube 22 become extremely high.

Therefore, by increasing the height of the lower ends of both ends of the reflector 16, it is possible to suppress the obstruction of the rising airflow, and as a result, it is possible to reduce the temperature rise of the heater wire 23. As shown in the characteristic diagram of FIG.
Assuming that the temperature rise of the heater wire 23 when the height is lowered to the center height of 100% is 100%, when the height of the lower end of both ends of the reflection plate 16 is set to the position of the upper end of the glass tube 22, the temperature rise is 3.7%. It has been confirmed that the temperature can be reduced, and when the position is higher than that, there is an effect of reducing the temperature rise by 4.9%. However, if the height of the lower ends of both ends of the reflection plate 16 is too high, the above-described effect of preventing the defrost water from dripping may be impaired. Therefore, the height of the heater wire 23 is increased by raising the lower end height of both ends of the reflecting plate 16 to a position equal to or higher than the upper end height of the glass tube 22 while considering the effect of preventing defrosting water from dropping.
It can be reduced by 7 to 4.9%.

Specifically, when isobutane is used as the flammable refrigerant, its ignition point temperature is about 460 ° C., whereas the general defrosting means 18 uses the heater wire 23 at the time of defrosting. Since the temperature is about 500 to 600 ° C., the temperature of the heater wire 23 is increased by about 19 to 2 according to the present embodiment.
9 ° C can be suppressed. Further, since the defrosting performance is improved by improving the heat radiation performance from the heater wire 23, when assuming that the same defrosting performance as that of the related art is ensured, the electric input to the heater wire 23 is reduced. Thus, the temperature of the heater wire 23 can be further reduced. Accordingly, even if defrosting is performed in an environment where the combustible refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

In the present embodiment, the reflecting plate 16 has a U-shape which is convex upward, but is not limited to the U-shape. Is a glass tube 2
Only one side may be formed so as to have a height equal to or more than the height of the outer periphery upper end of the second side.

(Embodiment 2) Embodiment 2 of 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 sectional view of the defrosting means 18 shown in FIG.

As shown in FIG. 5, in the defrosting means 18, a ventilation hole is opened in the reflection plate 16, and a part of the formed reflection plate 16 covers the ventilation hole.

The operation of the defrosting means 18 configured as described above will be described below. When the defrosting means 18 operates, the amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a rise in the temperature of the heater wire itself and external heat radiation through the air and the glass tube 22. Used for defrosting operation through the convection and radiation of air.

At this time, the temperature of the air near the defrosting means 18 becomes high due to the heat radiation from the heater wire 23, but the rising airflow due to natural convection flows not only from both ends of the reflection plate 16 but also from the ventilation provided at the upper part of the glass tube. It is also formed through the opening 26. Thereby, the high-temperature air between the glass tube 22 and the reflecting plate 16 smoothly flows upward and the heat radiation effect by convective heat transfer is enhanced.

As a result, the temperature of the air in the vicinity of the defrosting means 18 is reduced, and the performance of radiating heat from the heater wire 23 is improved, so that the temperature rise of the heater wire 23 itself can be suppressed. Further, since the ventilation port 26 is covered by a part of the reflection plate 16, the effect of preventing the defrosted water from dropping is not impaired, and the effect of reflecting the radiant heat emitted from the heater wire 23 can be similarly maintained. .

Further, since the defrosting performance is improved by improving the heat radiation performance from the heater wire 23, if it is assumed that the same degree of defrosting performance as in the prior art is ensured, the heating wire 23 The temperature of the heater wire 23 can be further reduced by reducing the electric input. Accordingly, even if defrosting is performed in an environment where the combustible refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

In this embodiment, the air vent 26 provided in the reflection plate 16 is located directly above the glass tube 22, but not directly above the glass tube 22 but by avoiding the glass tube 22. May be provided in the vicinity of the end. In this case, since the defrost water falling on the reflecting plate 16 drops along the end of the reflecting plate 16 without dripping onto the glass tube, it is not necessary to cover the ventilation port 26 with a part of the reflecting plate 16. Absent.

Embodiment 3 Embodiment 3 of 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. 6 is a sectional view of the defrosting means 18 shown in FIG.
FIG. 7 is a characteristic diagram showing a relationship between the width of the ventilation hole 26 and the temperature rise of the heater wire 23.

As shown in FIG. 6, the defrosting means 18 is configured such that the opening width of the ventilation port 26 provided in the reflection plate 16 is larger than the radius of the glass tube 22.

The operation of the defrosting means 18 configured as described above will be described below. When the defrosting means 18 operates, the amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a rise in the temperature of the heater wire itself and external heat radiation through the air and the glass tube 22. Used for defrosting operation through the convection and radiation of air.

At this time, the heat radiation performance from the heater wire 23 is improved by smooth natural convection while maintaining the effect of preventing the defrost water from dripping and reflecting the radiant heat from the heater wire 23 as shown in the second embodiment. The temperature rise of the heater wire 23 can be suppressed. From FIG. 7, assuming that the temperature rise of the heater wire 23 when there is no vent 26 is 100%, when the width of the vent 26 is the same as the radius of the glass tube, FIG.
It can be confirmed that 5% of the temperature rise suppression effect is obtained, and when the opening width of the vent 26 is further increased, the temperature rise reduction effect is 8.4%.

Thus, when the opening width of the vent 26 is smaller than the radius of the glass tube 22, the effect of suppressing the temperature rise is small,
6.5 to 8.4% when the radius is equal to or larger than the radius of the glass tube 22.
The effect of suppressing a stable temperature rise can be obtained. Specifically, when isobutane is used as the flammable refrigerant, its ignition point temperature is about 460 ° C., whereas the temperature of the heater wire 23 during defrosting is about 50
Since the temperature is about 0 to 600 ° C., the temperature rise of the heater wire 23 can be suppressed to about 33 to 50 ° C. by this embodiment.

Further, since the defrosting performance is improved by improving the heat radiation performance from the heater wire 23, if it is assumed that the same degree of defrosting performance as the conventional one is secured, the heating wire The temperature of the heater wire 23 can be further reduced by reducing the electric input. Accordingly, even if defrosting is performed in an environment where the combustible refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

In this embodiment, as in the second embodiment, the ventilation port 26 provided in the reflection plate 16 is
Although it is located just above the glass plate 22, it may be provided not near the glass tube 22 but near the end of the reflector, avoiding the glass tube 22. In this case, since the defrost water falling on the reflecting plate 16 drops along the end of the reflecting plate 16 without dripping onto the glass tube, it is not necessary to cover the ventilation port 26 with a part of the reflecting plate 16. Absent.

(Embodiment 4) Embodiment 4 of 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. 8 is a sectional view of the defrosting means 18.

As shown in FIG. 8, in the defrosting means 18, the reflecting plate 16 is configured so as to be inclined in the circumferential direction of the glass tube 22.

The operation of the defrosting means 18 configured as described above will be described below. When the defrosting means 18 operates, the amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a rise in the temperature of the heater wire itself and external heat radiation through the air and the glass tube 22. Used for defrosting operation through the convection and radiation of air. At this time, the temperature of the air near the defrosting means 18 becomes high due to the heat radiation from the heater wire 23, and an upward airflow due to natural convection occurs.

Here, since the reflecting plate 16 is inclined in the circumferential direction of the glass tube 22, the generated upward airflow is reflected by the reflecting plate 1.
6 smoothly rises along the direction of inclination, and the heat dissipation performance from the air near the defrosting means 18 is enhanced by convective heat transfer. As a result, the temperature of the air in the vicinity of the defrosting means 18 decreases, and the performance of radiating heat from the heater wire 23 is improved.
It is possible to suppress the temperature rise of itself.

Further, since the upper portion of the glass tube 22 is covered with the reflection plate 16, the effect of preventing the defrosting water from dripping is not impaired, and the effect of reflecting the radiant heat emitted from the heater wire 23 is also maintained. it can.

Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire 23, when it is assumed that the same degree of defrosting performance as that of the related art is ensured, the power consumption of the heater wire 23 is reduced. The temperature of the heater wire 23 can be further reduced by reducing the electric input. Accordingly, even if defrosting is performed in an environment where the combustible refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

In the present embodiment, the reflecting plate 16 is inclined in one direction in the circumferential direction of the glass tube 22, but the reflecting plate 16 is alternately inclined in the axial direction of the glass tube 22. The specification may be such that the updraft is rectified by changing it.

Embodiment 5 Embodiment 5 of 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. 9 is a sectional view of the cool air return air passage opening 25 and the defrosting means 18 provided at the lower part of the cooling chamber.

As shown in FIG. 9, in the defrosting means 18, the reflection plate 16 is configured so as to be inclined toward the cool air return air passage opening 25 provided at the lower part of the cooling chamber.

The operation of the defrosting means 18 configured as described above will be described below. When the defrosting means 18 operates, the amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a rise in the temperature of the heater wire itself and external heat radiation through the air and the glass tube 22. Used for defrosting operation through the convection and radiation of air.

At this time, the heat in the vicinity of the defrosting means 18 becomes high due to the heat radiation from the heater wire 23, and an upward airflow is generated by natural convection. Here, the reflecting plate 16 is inclined in the circumferential direction of the glass tube 22 toward the direction of the cool air return air passage opening 25 provided at the lower part of the cooling chamber. Rises smoothly along, and a part of it flows out into the connected refrigerator compartment.

Further, the cool air which is attracted by the above-mentioned ascending air flow and enters from the cool air return air passage opening 25 is reflected by the reflection plate 16.
Convection along with the natural convection smoothly, the convective heat transfer is improved, and the heat dissipation performance from the air near the defrosting means 18 is enhanced. As a result, the temperature of the air in the vicinity of the defrosting means 18 decreases, and the performance of radiating heat from the heater wire 23 improves, so that the temperature rise of the heater wire 23 itself can be suppressed.

Further, since the upper part of the glass tube 22 is covered with the reflection plate 16, the effect of preventing the defrosting water from dripping is not impaired, and the effect of reflecting the radiant heat emitted from the heater wire 23 is also maintained. it can.

Further, since the defrosting performance is improved by improving the heat radiation performance from the heater wire 23, when it is assumed that the same degree of defrosting performance as the conventional one is secured, the heating wire The temperature of the heater wire 23 can be further reduced by reducing the electric input. Accordingly, even if defrosting is performed in an environment where the combustible refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

Embodiment 6 Embodiment 6 of 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. 10 is a sectional view of the defrosting means 18, and FIG. 11 is a characteristic diagram showing the relationship between the width of the reflector 16 and the temperature rise of the heater wire 23.

As shown in FIG. 10, the defrosting means 18 is configured such that the width of the reflection plate 16 is not more than twice the diameter of the glass tube 22.

The operation of the defrosting means 18 configured as described above will be described below. When the defrosting means 18 operates, the amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a rise in the temperature of the heater wire itself and external heat radiation through the air and the glass tube 22. Used for defrosting operation through the convection and radiation of air. At this time, generally, the effect of preventing the defrosted water from dropping onto the glass tube 22 of the reflector 16 and the heater wire 23
In order to ensure sufficient reflection of radiant heat emitted from
In many cases, the width of the reflector 16 is at least twice the diameter of the glass tube. In this case, natural convection is inhibited by the reflector 16 and heat transport by convection is hindered. As a result, the air temperature near the defrosting means 18 decreases. As a result, the temperature of the heater wire 23 and the glass tube 22 becomes extremely high.

Therefore, the width of the reflection plate 16 is set to be twice or less the diameter of the glass tube 22 to suppress the obstruction of the updraft,
As a result, the temperature rise of the heater wire 23 can be reduced. As shown in the characteristic diagram of FIG. 11, assuming that the temperature rise of the heater wire 23 when the width of the reflector 16 is three times the diameter of the glass tube 22 is 100%, the width of the reflector 16 is When the diameter is twice as large, the temperature rise can be reduced by 6.5%.
It has been confirmed that there is an effect of reducing the temperature rise by 8%.

However, if the width of the reflecting plate 16 is too small, the above-described effect of preventing the defrosting water from dropping and the effect of reflecting radiant heat may be impaired. Therefore, by taking the width of the reflecting plate 16 to be twice or less the diameter of the glass tube 22 while considering the effect of preventing defrosted water from dripping and the effect of reflecting radiant heat, the temperature rise of the heater wire 23 is 6.5 to 6.8. % Can be reduced. Specifically, when isobutane is used as the flammable refrigerant, its ignition point temperature is about 460 ° C., whereas the general defrosting means 18 uses the heater wire 23 during defrosting.
Is about 500 to 600 ° C., the temperature rise of the heater wire 23 can be suppressed to about 33 to 41 ° C. by this embodiment.

Further, since the defrosting performance is improved by improving the heat radiation performance from the heater wire 23, when it is assumed that the same degree of defrosting performance as that of the related art is ensured, the heating wire 23 The temperature of the heater wire 23 can be further reduced by reducing the electric input. Accordingly, even if defrosting is performed in an environment where the combustible refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

In the present embodiment, the reflecting plate 16 has a U-shape that is convex upward, but is not limited to the U-shape.

Embodiment 7 Embodiment 7 of 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. 12 is a sectional view of the defrosting means 18, and FIG. 13 is a characteristic view showing the effect of the present embodiment.

As shown in FIG. 12, the defrosting means 18 is formed such that both ends of the reflecting plate 16 are formed downward and the height of the lower end is equal to or higher than the height of the outer peripheral upper end of the glass tube 22. And the reflector 16 is disposed so as to be inclined toward the side of the cool air return opening 25 provided in the lower part of the cooling chamber, and the width of the reflector 16 is smaller than that of the glass tube 22. It is configured to be no more than twice the diameter.

The operation of the defrosting means 18 configured as described above will be described below. When the defrosting means 18 operates, the amount of heat converted from electric energy to heat energy by the heater wire 23 can be classified into a rise in the temperature of the heater wire itself and external heat radiation through the air and the glass tube 22. Used for defrosting operation through the convection and radiation of air. At this time, the temperature of the air near the defrosting means 18 becomes high due to the heat radiation from the heater wire 23, and an upward airflow due to natural convection occurs.

Therefore, by forming both ends of the reflecting plate 16 downward and forming the lower end height to be equal to or higher than the outer upper end height of the glass tube 22, the natural convection ascending past the end portion of the reflecting plate 16 is increased. In addition to smoothing the development, a ventilation hole 26 is provided in the reflection plate 16 to form a natural convection that develops directly upward from the glass tube, and the cool air return air passage opening 25 is formed.
The height of the lower end opposite to the cold air return air passage opening 25 is made higher than the lower end height of the end of the reflector 16 provided on the side, and the reflector 16 is inclined substantially toward the cool air return air passage opening 25 side. Thereby, the internal cold air flowing from the cool air return air passage opening 25 is smoothly taken into the upward airflow, and the width of the reflection plate 16 is set to be equal to or less than twice the diameter of the glass tube 22 so that natural convection is further achieved. Can promote the development of.

As a result, natural convection can be developed more than using the first to seventh embodiments alone, and the temperature of the air near the defrosting means 18 can be reduced by convective heat transfer. Thereby, the heat radiation performance from the heater wire 23 can be improved, and the temperature rise of the heater wire 23 itself can be largely suppressed. In the characteristic diagram of FIG.
Lower the lower end height of both ends to the center height of the glass tube 22,
Further, based on the specification of the heater wire 23 in the case where the ventilation hole 26 is not provided in the reflection plate and the width of the reflection plate 16 is set to be three times the diameter of the glass tube 22, the temperature rise is set to 100%. It shows the temperature rise of the heater wire 23 in the first, third, seventh embodiments and the present embodiment.

FIG. 13 shows that in the present embodiment, the temperature rise of the heater wire 23 can be reduced by 10.0%, and the effect of reducing the temperature rise is larger than in any of the other embodiments. Specifically, when isobutane is used as the flammable refrigerant, its ignition point temperature is about 460 ° C., whereas the temperature of the heater wire 23 during defrosting is about Since the temperature is about 500 to 600 ° C., the temperature of the heater wire 23 is increased by about 50 to 60 ° C. according to the present embodiment.
Can be suppressed. Furthermore, since the heat dissipation performance from the heater wire 23 is improved, the defrosting performance is improved.
Assuming that the same level of defrosting performance as that of the related art is assured, the electric input to the heater wire 23 can be reduced to further lower the temperature of the heater wire 23. This allows
Even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

It is needless to say that the present embodiment maintains the effect of preventing the defrosted water from dropping onto the glass tube 22 and the effect of reflecting the radiant heat emitted from the heater wire 23.

[0086]

As is apparent from the above description, the first aspect of the present invention provides a refrigeration cycle in which a compressor, a condenser, a pressure reducing mechanism, and an evaporator are functionally connected and a flammable refrigerant is charged.
A cooling chamber in which the evaporator is housed, and a defrosting unit for defrosting frost adhering to the evaporator in the cooling chamber, wherein the defrosting unit comprises a spirally wound metal resistor. A heater wire, and a glass tube covering the heater wire,
A reflector disposed on the upper part of the glass tube, wherein the end of the reflector is formed downward and the lower end height of the reflector end is equal to or higher than the outer peripheral upper end height of the glass tube. By having a molded feature, the prevention of dripping of defrost water onto the glass tube and the reflection of heat emitted from the heater wire toward the lower part of the cooling chamber to melt frost deposited on the lower part of the cooling chamber by radiant heat. While maintaining the function of causing, the temperature of the convective high-temperature air can be reduced by increasing the natural convection effect in which high-temperature air staying between the glass tube and the reflector convects upward and transports heat upward, As a result, the amount of heat radiation from the heater wire can be increased and the heater wire itself can be maintained at a low temperature. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced.
Therefore, even if defrosting is performed in an environment where flammable refrigerant leaks from the refrigeration cycle into the refrigerator,
The possibility of ignition can be suppressed.

Further, according to the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is charged, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire A glass tube that covers the glass tube, and a reflector provided on the upper portion of the glass tube, and having a feature in which a vent is provided in the reflector, to prevent defrosting water from dropping onto the glass tube. The heat emitted from the heater wire is reflected toward the lower part of the cooling chamber to maintain the function of melting the frost deposited on the lower part of the cooling chamber by radiant heat, and the high-temperature air staying between the glass tube and the reflecting plate is directly heated. Pass through the vent Thermal Te and for transporting upwardly the can be reduced temperature dwell hot air, can result amount of heat radiated from the heater wire to maintain the heater wire itself to a low temperature increase. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. Therefore, even if defrosting is performed in an environment where the flammable refrigerant leaks from the refrigeration cycle into the refrigerator, the possibility of ignition can be suppressed.

The invention according to claim 3 is the same as the invention according to claim 2.
In the invention described in the above, by providing a feature that the opening width of the vent is formed so as to be equal to or larger than the radius of the glass tube, prevention of dripping of defrost water onto the glass tube and heat released from the heater wire. While maintaining the function of reflecting the frost accumulated in the lower part of the cooling chamber by reflecting the radiant heat in the lower part of the cooling chamber, the natural convection formed via the vent can be smoothly and stably developed. The effect of reducing the temperature rise of the heater wire can be increased. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason,
Even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

Further, the invention according to claim 4 provides a refrigeration cycle in which a compressor, a condenser, a pressure reducing mechanism, and an evaporator are functionally connected to each other and a flammable refrigerant is filled therein, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire A glass tube that covers the glass tube, and a reflector provided above the glass tube, wherein the reflector is provided so as to be inclined in a circumferential direction of the glass tube. The natural convection due to the high-temperature air in the vicinity of the defrosting means is smoothly developed along the inclination of the reflection plate while maintaining the effect of preventing the defrosting water from dropping onto the pipe and the effect of reflecting the radiant heat emitted from the heater wire. The heater wire It is possible to suppress the Atsushi Nobori. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced.
For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

The invention described in claim 5 is the same as the invention described in claim 4.
In the invention described in the above, by providing a feature that the reflection plate is arranged so as to be inclined toward the cold air return air passage opening side provided in the lower part of the cooling chamber, by the high temperature air near the defrosting means By smoothly joining the cool air flowing from the cool air return airflow opening to the natural convection, the convective heat transfer effect can be improved, and the temperature rise of the heater wire can be further suppressed. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

Further, according to the present invention, there is provided a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire A glass tube that covers the glass tube, and a reflector provided on the upper portion of the glass tube, wherein the width of the reflector is shaped to be equal to or less than twice the diameter of the glass tube. Natural convection by high-temperature air near the defrosting means can be smoothly and stably developed while maintaining the effect of preventing defrosting water from dropping onto the glass tube and the effect of reflecting radiant heat emitted from the heater wire. Heating of the heater wire It can be suppressed. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

The invention according to claim 7 provides a refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled, and a cooling system in which the evaporator is housed. Chamber, and defrosting means for defrosting frost adhering to the evaporator inside the cooling chamber, wherein the defrosting means comprises a heater wire made of a spirally wound metal resistor, and the heater wire And a reflector disposed above the glass tube, wherein the end of the reflector is shaped downward and the lower end of the end of the reflector is lower than the outer periphery of the glass tube. And a ventilation hole is provided in the reflection plate, and the reflection plate is disposed so as to incline toward a cool air return air passage opening side provided in a lower portion of the cooling chamber. And the width of the reflector is at least twice the diameter of the glass tube. By having a feature that is shaped so that the natural convection that rises past the end of the reflector is smoothed, and the reflector is provided with the vent and develops directly upward from the glass tube. Forming natural convection, and making the lower end height on the opposite side of the cold air return air passage opening portion higher than the lower end height of the reflector end provided on the cold air return air passage opening side, and reflecting the light. By inclining the plate approximately toward the cold air return air passage opening side, the cold air in the refrigerator flowing from the cold air return air passage opening is smoothly taken into the ascending airflow, and the width of the reflection plate is equal to the diameter of the glass tube. By configuring so as to be twice or less, natural convection can be smoothly and stably developed.

As a result, the air temperature in the vicinity of the defrosting means is reduced by the convective heat transfer, the heat radiation performance from the heater wire is improved, and the temperature rise of the heater wire itself can be largely suppressed. Furthermore, since the defrosting performance is improved by improving the heat radiation performance from the heater wire, in order to ensure the same level of defrosting performance as before, the electric input to the heater wire is reduced and the heater The temperature of the wire can be further reduced. For this reason, even if defrosting is performed in an environment where the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the possibility of ignition can be suppressed.

[Brief description of the drawings]

FIG. 1 is a refrigeration system diagram of a refrigerator according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a defrosting unit according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a defrosting unit according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of a defrosting unit according to Embodiment 2 of the present invention.

FIG. 6 is a sectional view of a defrosting unit according to Embodiment 3 of the present invention.

FIG. 7 is a characteristic diagram according to the third embodiment of the present invention.

FIG. 8 is a sectional view of a defrosting unit according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view of a defrosting unit according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view of a defrosting unit according to a sixth embodiment of the present invention.

FIG. 11 is a characteristic diagram according to the sixth embodiment of the present invention.

FIG. 12 is a sectional view of a defrosting unit according to a seventh embodiment of the present invention.

FIG. 13 is a characteristic diagram according to the seventh embodiment of the present invention.

FIG. 14 is a schematic longitudinal sectional view of a conventional refrigerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Evaporator 16 Reflector 18 Defrosting means 19 Compressor 20 Condenser 21 Decompression mechanism 22 Glass tube 23 Heater wire 24 Cap 25 Cold air return opening 26 Air vent

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Shimizu 4-5-2-5 Takaidahondori, Higashiosaka-shi, Osaka Matsushita Refrigerator Co., Ltd. F-term (reference) 3L045 AA04 AA07 BA01 CA02 DA02 EA01 HA01 KA00 PA01 PA04 3L046 AA04 AA07 BA01 CA07 MA01 MA04

Claims (7)

[Claims] 1. A refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is filled therein.
A cooling chamber in which the evaporator is housed, and a defrosting unit for defrosting frost adhering to the evaporator in the cooling chamber, wherein the defrosting unit comprises a spirally wound metal resistor. A heater wire, and a glass tube covering the heater wire,
A reflector disposed on the upper part of the glass tube, wherein the end of the reflector is formed downward and the lower end height of the reflector end is equal to or higher than the outer peripheral upper end height of the glass tube. A refrigerator characterized by being molded. 2. A refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected and a flammable refrigerant is charged.
A cooling chamber in which the evaporator is housed, and a defrosting unit for defrosting frost adhering to the evaporator in the cooling chamber, wherein the defrosting unit comprises a spirally wound metal resistor. A heater wire, and a glass tube covering the heater wire,
A refrigerator, comprising: a reflector disposed above the glass tube, wherein the reflector has a vent. 3. The refrigerator according to claim 2, wherein an opening width of the vent is formed so as to be larger than a radius of the glass tube. 4. A refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected, and a flammable refrigerant is charged.
A cooling chamber in which the evaporator is housed, and a defrosting unit for defrosting frost adhering to the evaporator in the cooling chamber, wherein the defrosting unit comprises a spirally wound metal resistor. A heater wire, and a glass tube covering the heater wire,
A refrigerator comprising: a reflecting plate disposed above the glass tube; and the reflecting plate is disposed so as to be inclined in a circumferential direction of the glass tube. 5. The refrigerator according to claim 4, wherein the reflection plate is disposed so as to be inclined toward a cool air return air passage opening provided at a lower portion of the cooling chamber. 6. A refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected, and a flammable refrigerant is filled therein.
A cooling chamber in which the evaporator is housed, and a defrosting unit for defrosting frost adhering to the evaporator in the cooling chamber, wherein the defrosting unit comprises a spirally wound metal resistor. A heater wire, and a glass tube covering the heater wire,
A refrigerator comprising a reflector disposed above the glass tube, wherein the width of the reflector is less than twice the diameter of the glass tube. 7. A refrigeration cycle in which a compressor, a condenser, a decompression mechanism, and an evaporator are functionally connected, and a flammable refrigerant is filled therein.
A cooling chamber in which the evaporator is housed, and a defrosting unit for defrosting frost adhering to the evaporator in the cooling chamber, wherein the defrosting unit comprises a spirally wound metal resistor. A heater wire, and a glass tube covering the heater wire,
A reflector disposed on the upper part of the glass tube, wherein the end of the reflector is formed downward and the lower end height of the reflector end is equal to or higher than the outer peripheral upper end height of the glass tube. The reflector is provided with a vent, and the reflector is disposed so as to be inclined toward a cold air return air passage opening provided in a lower portion of the cooling chamber, and A refrigerator formed so that a width thereof is equal to or less than twice a diameter of the glass tube.