JP3482406B2 - Freezer refrigerator - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, Japanese Patent Application Laid-Open No. 8-54172 has been proposed as a refrigerator / freezer having a defrosting means for an evaporator. Hereinafter, the conventional refrigerator-freezer will be described with reference to the drawings.

FIG. 31 is a longitudinal sectional view of a main part of a conventional refrigerator-freezer. In FIG. 31, 1 is a refrigerator / freezer body, 2
Is a freezer compartment inside the freezer / refrigerator body 1, 3 is a refrigerating compartment inside the freezer / refrigerator body 1, 4 is a freezer compartment door, 5 is a refrigerating compartment door, and 6 is a partition wall for partitioning the freezer compartment 2 from the refrigerating compartment 3. , 7 is a freezer inlet for sucking air in the freezer 2, and 8 is a refrigerator 3.
A refrigerating chamber suction port for sucking air therein, 9 a discharge port for discharging cold air, 10 an evaporator, and 11 a fan for circulating cold air.

Reference numeral 12 is an evaporator partition wall for partitioning the evaporator 10 from the freezer compartment 2, 13 is a trough, 14 is a drain port, and 15 is a defrosting tube heater in which a nichrome wire is coiled and covered with a glass tube. , 16 is a roof for preventing evaporation noise generated when defrosting water directly drops on and contacts the defrosting tube heater 15,
Reference numeral 17 denotes a metal bottom plate which is installed between the vat 13 and the defrosting tube heater 15 and is insulated and held.

Next, the operation will be described. When cooling the freezer compartment 2 or the refrigerating compartment 3, the refrigerant flows through the evaporator 10 to cool the evaporator 10. Fan 11
Is operated to send the temperature-raising air in the freezing compartment 2 or the refrigerating compartment 3 to the cooling compartment 20 from the freezing compartment suction opening 7 or the refrigerating compartment suction opening 8 to be cooled by exchanging heat with the evaporator 10 to be cooled from the discharge opening 9. The air is sent into the freezer compartment 2, and cold air is sent from the freezer compartment 2 to the refrigerating compartment through a communication port (not shown).

Here, the air that exchanges heat with the evaporator 10 is
Since the air is highly humidified by the inflow of high temperature outside air by opening and closing the freezing compartment door 4 and the refrigerating compartment door 5 and the evaporation of the moisture of the stored food in the freezing compartment 2 and the refrigerating compartment 3, the temperature is lower than that air. Moisture in the air turns into frost on the evaporator 10 to form frost,
As the amount of frost increases, the heat transfer between the surface of the evaporator 10 and the air that exchanges heat is hindered, and the air flow resistance is reduced to reduce the air flow rate, so that the heat transmission rate is reduced and insufficient cooling occurs.

Therefore, the nichrome wire of the defrosting tube heater 15 is energized before the cooling becomes insufficient. When energization of the nichrome wire is started, heat rays are radiated from the nichrome wire to the evaporator 10 and peripheral parts. At this time, a part of the heat ray radiated to the bottom plate 17 is reflected by the heater wire from the shape of the bottom plate 17,
Others are reflected toward the evaporator 10 and other peripheral components.

As a result, the evaporator 10, the trough 13 and the drain port 1
Melt frost around 4 into water. In addition, a part of the defrosted water melted in this way directly falls into the tub 13, and the other part is covered by the roof 16 to avoid the defrosting pipe heater 15 and
And is drained from the drainage port 14 to the outside of the refrigerator.

[0009]

However, in the above-mentioned conventional structure, the glass surface temperature of the defrosting tube heater 15 is, of course, very high, not to mention the surface of the nichrome wire, and the bottom plate 17 is a tube. The temperature of the tube heater 15 rises abnormally because it is in the vicinity of the heater 15 and part of the heat rays radiated from the tube heater 15 are reflected back to the tube heater 15, and the temperature exceeds the ignition temperature of the flammable refrigerant. From this, when a flammable refrigerant is used as the refrigerant and the flammable refrigerant leaks from the pipe installed in the portion communicating with the evaporator 10 or the inside of the refrigerator, the defrosting tube heater 15 is energized. There was a problem that there is a risk of ignition and explosion.

In view of the above problems, the present invention provides a freezer-refrigerator capable of suppressing the risk of ignition of the flammable refrigerant even when defrosting is performed in an environment where the flammable refrigerant leaks to the installation atmosphere of the defrosting means. The purpose is to provide.

[0011]

In order to achieve the above object, a refrigerator-freezer of the present invention is provided with an evaporator of a refrigeration cycle, and
Defrost heater for defrosting frost on the evaporator
And a flammable refrigerant enclosed in the refrigeration cycle
The defrosting heater is a glass tube and the inside of the glass tube.
Of a metal resistor having a spiral portion provided in the
Heater wire and the spiral part of the heater wire
Adjacent to each other by setting the pitch to 2 mm or more
Suppresses temperature variations by reducing the influence from the heater wire
In addition, the heater wire is exposed to Joule heat in the spiral section.
Heat generation per unit area by dividing the heat generation amount by the surface area
The flammability is controlled so that the amount becomes less than 2.5 W / cm2.
This is to reduce the risk of ignition when the refrigerant leaks .

Further, the evaporator of the refrigeration cycle and the steam
A defrosting heater for defrosting the frost attached to the generator,
With a flammable refrigerant enclosed in the refrigeration cycle,
The defrosting heater is installed inside the glass tube and the glass tube.
Heater composed of a metal resistor having a spiral portion provided
The heater wire and the spiral part of the heater wire
By setting the pitch to 2 mm or more,
Suppresses temperature variations by reducing the influence from the
In addition, the above-mentioned heater wire makes the heat generation amount of the spiral part spiral.
The value divided by the volume surrounded by the outer diameter and the length of the
/ Cm3 less than the flammable refrigerant leakage
It is designed to reduce the risk of fire in case of fire .

Further, an evaporator of a refrigeration cycle, and
Defrost heater for defrosting frost on the evaporator
And a flammable refrigerant enclosed in the refrigeration cycle
The defrosting heater is a glass tube and the inside of the glass tube.
Of a metal resistor having a spiral portion provided in the
It corresponds to the length of the spiral part.
Unit surface of the heater wire with respect to the inner surface area of the glass tube
By setting the calorific value per product to less than 1.6 W / cm2,
Decrease glass tube temperature, and decrease the glass tube temperature
The glass tube reduces the amount of external heat radiation through the glass tube.
Defrosting ability is secured by supplementing by increasing the heat transfer area of
However, there is a risk of ignition if the flammable refrigerant leaks.
It is designed to be low .

Therefore, in a refrigeration cycle using a flammable refrigerant, even if defrosting is performed in an environment in which the flammable refrigerant leaks into the installation atmosphere of the defrosting heater, there is a risk of ignition of the flammable refrigerant. Sex can be suppressed.

The invention according to claim 1 of the present invention relates to frozen
Defrost cycle evaporator and frost attached to said evaporator
Heater for defrosting and enclosed in the refrigeration cycle
The defrosting heater is equipped with a combustible refrigerant
It has a lath tube and a spiral part inside the glass tube.
A heater wire made of a metal resistor,
The pitch of the spiral part of the turn wire should be 2 mm or more.
Minimizes the effect of adjacent heater wires
Suppresses temperature variations, and the heater wire is
Divide the calorific value due to Joule heat in the yallar area by its surface area.
The calorific value per unit area is less than 2.5 W / cm2
Temperature fluctuation due to variations in the pitch of the spiral part
Since the roughness can be reduced, the spiral parts are
The influence from the heater wire can be reduced and the
Compared to the line part, the temperature is affected by the adjacent parts
The amount of heat generated per unit area in the spiral part where the degree becomes higher
By less than 2.5 W / cm2
The heater wire is a flammable refrigerant while ensuring defrosting ability and longevity.
Is less than the ignition temperature of.

Further, if the total heat generation amount of the heater wire is increased, the surface temperature of the heater wire rises, but even if the total heat generation amount is increased, the heat generation amount per unit area is 2.5 W / cm ²
By designing to be less than, the heater wire will be below the ignition temperature of the flammable refrigerant regardless of the total heat generation amount of the heater wire.

From this, it is possible to easily design the defrosting means for making the temperature below the ignition temperature of the flammable refrigerant, and it is possible to increase the total calorific value of the heater wire while maintaining the temperature below the ignition temperature of the flammable refrigerant.

The invention according to claim 2 of the present invention is a refrigerator
Defrost cycle evaporator and frost attached to said evaporator
Heater for defrosting and enclosed in the refrigeration cycle
The defrosting heater is equipped with a combustible refrigerant
It has a lath tube and a spiral part inside the glass tube.
A heater wire made of a metal resistor,
The pitch of the spiral part of the turn wire should be 2 mm or more.
Minimizes the effect of adjacent heater wires
Suppresses temperature variations, and the heater wire is
The amount of heat generated by the spiral section is surrounded by the outer diameter and length of the spiral section.
Since the value divided by the volume is less than 8.5 W / cm3,
Temperature variations due to variations in the pitch of the spiral part
The heaters that are adjacent to each other in the spiral part can be made smaller
The influence from the heating wire can be reduced, the defrosting capacity and the life equivalent to or more than the conventional one can be secured, and the total calorific value of the heating wire can be increased while maintaining the temperature below the ignition temperature of the flammable refrigerant.

Further, even when the outer diameter of the spiral portion changes, the heater is designed so that the calorific value with respect to the volume calculated from the outer diameter and the length of the spiral portion is less than 8.5 W / cm ^3. The heater wire is below the ignition temperature of the flammable refrigerant without affecting the outer diameter of the spiral part of the wire.

From this, it is possible to more easily design the defrosting means to make the temperature below the ignition temperature of the flammable refrigerant, and to maintain the temperature below the ignition temperature of the flammable refrigerant while maintaining the outer diameter of the spiral portion of the heater wire and the total calorific value. Can be changed freely.

The invention according to claim 3 of the present invention is a refrigerator
Defrost cycle evaporator and frost attached to said evaporator
Heater for defrosting and enclosed in the refrigeration cycle
The defrosting heater is equipped with a combustible refrigerant
It has a lath tube and a spiral part inside the glass tube.
Heater wire consisting of a metal resistor
For the inner surface area of the glass tube corresponding to the length of the yral
The heating value per unit area of the heater wire is 1.6 W / c
Heat transfer due to temperature decrease of glass tube by setting less than m2
The decrease in the amount can be compensated for by the heat transfer area of the glass tube.
While maintaining the same total heat dissipation from the lath tube as before,
The temperature of the glass tube, which correlates with the temperature of the
It

From this, the defrosting ability equal to or higher than the conventional one
And secures the service life of the heater wire while generating flammable refrigerant.
The temperature can be kept below the fire temperature and flammable refrigerant leaks into the atmosphere of the defrosting means
Even if defrosting is performed in case of leakage, the risk of ignition is lower.
I can do it. Furthermore, regardless of the heating value of the entire heater wire
Easy design of defrosting means to keep the temperature below the ignition temperature of flammable refrigerant
You can

The invention according to claim 4 of the present invention is the invention according to any one of claims 1 to 3,
The defrosting means is one in which a glass tube and a heater wire made of a metal resistor are installed inside the glass tube. Since the glass tube has a wall thickness of 1.5 mm or less, the inner surface of the glass tube is received from the heater wire. The amount of heat transferred when the heat is transferred to the outer surface of the glass tube increases, and the heat smoothly released from the heater wire is radiated to the outside through the glass tube.

From this fact, the amount of heat released to the outside is further increased, the defrosting capacity is further improved, and the amount of heat released to the outside is reduced, so that the amount of heat used to raise the temperature of the heater wire is reduced. The surface temperature of the heater wire is further lowered and becomes lower than the ignition temperature of the flammable refrigerant.

FIG. 1 shows an embodiment of the present invention.
Starting from FIG. 30, description will be made. It should be noted that the same configurations as those of the conventional one are denoted by the same reference numerals and detailed description thereof will be omitted.

(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.

As shown in FIG. 1, 18 is a defrosting means for defrosting the frost adhering to the evaporator 10, and 19 is a compressor, 2
Reference numeral 0 is a condenser, 21 is a decompression mechanism, and a combustible refrigerant (not shown) is sealed inside the refrigeration cycle in which the compressor 19, the condenser 20, the decompression mechanism 21, and the evaporator 10 are functionally connected in an annular shape. ing.

The operation of the freezer-refrigerator constructed as above will be described below.

The operation of the compressor 19 cools the evaporator 10 of the refrigeration cycle, and the fan 11 that operates simultaneously with the operation of the compressor 19 ventilates the air inside the refrigerator / freezer-refrigerator to the cooled evaporator 10 to form an evaporator. The cold air that has exchanged heat with 10 is discharged into the refrigerator. Then, the defrosting means 18 is operated after an arbitrary operation time of the compressor 19 has elapsed.

By the operation of the defrosting means 18, the defrosting means 18 generates heat at a temperature lower than the ignition temperature of the flammable refrigerant used in the refrigeration cycle to defrost the evaporator 10.
The detection means (not shown) detects the completion of defrosting and stops the defrosting means to regularly prevent uncooling of the inside due to frost formation.

From this, even if defrosting is performed in the unlikely event that the flammable refrigerant in the refrigeration cycle leaks into the refrigerator, the defrosting means 18 is less than the ignition temperature of the flammable refrigerant used in the refrigeration cycle. Since it only reaches the temperature of, the risk of ignition is reduced.

(Embodiment 2) Embodiment 2 according to the invention
Will be described with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 2 is a vertical cross-sectional view of the essential parts of the refrigerator according to the second embodiment of the present invention.

As shown in FIG. 2, reference numeral 22 is a glass tube which is a constituent element of the defrosting means 18, 23 is a constituent element of the defrosting means 18, which is a heater wire made of a metal resistor inside the glass tube 22, Reference numeral 24 denotes a straight line portion formed of straight lines at both ends of the heater wire 23, 25 denotes a spiral portion other than the straight line portion 24, which has a spiral shape so that the heater wire 23 can be stored in a predetermined length of the glass tube 22, 26 Is a cap that prevents defrost water from entering the inside of the glass tube 20.

The operation of the freezer-refrigerator constructed as above will be described below.

When the defrosting means 18 is activated, the heater wire 2
3 is a heater wire 2 adjacent to each other as compared with the straight line portion 24
Spiral part 2 whose temperature rises due to the influence of 3
When the temperature of 5 heats up at a temperature lower than the ignition temperature of the flammable refrigerant, the frost of the evaporator 10 melts into water, and the evaporator 10
Drop from.

A part of the dropped water is the glass tube 22.
1 directly from the roof 16 or cap 26 without dripping
Drop to 3 and drop the others directly into tub 13 and tub 1
The water dropped on 3 is drained from the drain port 14 to the outside.

From this, the heater wire 2 which is a heating element
Most of the heat rays due to the radiation from No. 3 pass through the glass tube 22 and are radiated to the frost adhering to the evaporator 10 and peripheral parts, so that the surface temperature of the heater wire 23 is maintained while maintaining the defrosting ability equal to or higher than the conventional one. Is less than the ignition temperature of the flammable refrigerant, and the heater wire 23 can prevent corrosion deterioration due to direct contact of the defrost water with the cap 26. Defrosting means 1
Even if defrosting is performed in the case of leakage into the atmosphere of No. 8, the risk of ignition can be extremely reduced.

(Third Embodiment) A third embodiment of the present invention will be described with reference to the drawings. The same components as those in the second embodiment will be assigned the same reference numerals and detailed description thereof will be omitted.

FIG. 3 is a cross-sectional view of a main part in the third embodiment of the present invention.

As shown in FIG. 3, 27 is a heater wire 23.
L is a spiral length of the spiral part 25, which is connected to both ends of the spiral part 25.

The operation of the freezer-refrigerator constructed as above will be described below.

When the defrosting means 18 is activated, the lead wire 25
The heater wire 23 is input through and heats up. And
The heater wire 23 generates heat at a temperature lower than the ignition temperature of the flammable refrigerant in the vicinity of the center indicated by L / 2 where the temperature becomes higher in the spiral portion 25, and defrosts the evaporator 10.

Therefore, the surface temperature of the central portion in the length direction of the spiral portion 25 of the heater wire 23 is higher than that of the conventional one while ensuring the defrosting ability and the service life equal to or higher than those of conventional ones, but less than the ignition temperature of the flammable refrigerant. Since the temperature is 1, the risk of ignition can be further reduced even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means 18.

(Embodiment 4) Embodiment 4 of the present invention will be described with reference to the drawings. The same components as those in Embodiments 2 and 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 4 is a sectional view of the essential parts of the fourth embodiment of the present invention.

As shown in FIG. 4, h is a spiral portion 25.
Is the height of.

The operation of the refrigerator-refrigerator constructed as above will be described below.

During defrosting, the gas in the vicinity of the heater wire 23 is warmed by the heat generated by the heater wire 23 and moves upward, so that the gas in the glass tube 22 has a higher temperature in the upper part than in the lower part. Under this influence, since the heater wire 23 has the height h at the spiral portion 25, the upper portion of the spiral portion 25 has a high temperature. The surface temperature of the spiral portion 25 of the heater wire 23, which has a high temperature, generates heat at a temperature lower than the ignition temperature of the flammable refrigerant and defrosts the evaporator 10.

From the above, by ensuring the defrosting ability and the service life equal to or higher than those of the prior art, the temperature of the upper portion of the spiral portion 25, which is relatively high in the heater wire 23, is set to a temperature lower than the ignition temperature of the flammable refrigerant. Even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, the risk of ignition can be further reduced.

(Fifth Embodiment) A fifth embodiment of the present invention will be described with reference to the drawings. The same components as those in the second embodiment will be assigned the same reference numerals and detailed description thereof will be omitted.

FIG. 5 is a cross-sectional view of the main part of the fifth embodiment of the present invention, and FIG. 6 is a temperature characteristic diagram of the same embodiment.

As shown in FIG. 5, L is the spiral portion 25.
Is the length of. In addition, as shown in FIG. 6, the horizontal axis is the surface area of the heater wire 23 existing within the length L of the spiral portion 25 and the heat generation amount of Joule heat of the heater wire 23 existing within the length L of the spiral portion 25. The calorific value per unit surface area divided, the horizontal axis is the surface temperature of the heater wire 23.

The operation of the freezer-refrigerator constructed as above will be described below.

During defrosting, electricity is supplied to the heater wire 23 through the lead wire 27, and the heater wire 23 generates Joule heat. At this time, the defrosting means 18 defrosts the evaporator 10 with a calorific value of less than 2.5 W / cm ² per unit area of the heater wire 23 in the length L of the spiral part 25. .

Here, the surface temperature of the heater wire 23 rises as the heating value per unit area of the spiral portion 25 of the heater wire 23 increases, and when the heating value per unit area exceeds 2.5 W / cm ^2. The temperature is above the ignition temperature of the flammable refrigerant.

Therefore, when the heater wire 23 can be kept below the ignition temperature of the combustible refrigerant while securing the defrosting ability and the service life equal to or more than those in the conventional case, and the combustible refrigerant leaks into the atmosphere of the defrosting means 18, Even if defrosting is performed, the risk of ignition can be reduced. Further, if the total calorific value of the heater wire 23 is increased, the surface temperature of the heater wire 23 rises,
Even if the total calorific value is increased, the calorific value per unit area is 2.
By designing the heater wire 23 to have a temperature of less than 5 W / cm ² , the heater wire 23 can be heated to below the ignition temperature of the flammable refrigerant regardless of the heat generation amount of the entire heater wire 23. The frost means 18 can be easily designed, and the heater wire 23 can be maintained while maintaining the temperature below the ignition temperature of the flammable refrigerant.
It is possible to increase the total calorific value of.

In the present embodiment, isobutane is used as the type of flammable refrigerant, but other flammable refrigerants having the same ignition temperature as isobutane have the same effect.

Further, in the present embodiment, the temperature of the heater wire 23 is set lower than the ignition temperature of isobutane, but when an isobutane refrigerant is specifically used, it is safe with respect to the ignition temperature of isobutane of about 460 ° C. In consideration of the rate, it is necessary to set the temperature of the heater wire 23 to be 360 ° C. or less.
cm ² or less.

(Sixth Embodiment) A sixth embodiment of the present invention will be described with reference to the drawings. The same components as those in the second embodiment will be assigned the same reference numerals and detailed description thereof will be omitted.

FIG. 7 is a sectional view of the essential parts of the sixth embodiment of the present invention, and FIG. 8 is a temperature characteristic diagram of the same embodiment.

As shown in FIG. 7, D is the spiral portion 25.
Is the outer diameter of. In addition, as shown in FIG. 8, the horizontal axis indicates the volume of Joule heat generated by the heater wire 23 existing within the length L of the spiral portion 25, which is surrounded by the length L of the spiral portion 25 and the outer diameter D. The calorific value per unit volume divided by, and the vertical axis is the surface temperature of the heater wire 23.

The operation of the refrigerator-refrigerator constructed as above will be described below.

During defrosting, the defrosting means 18 has a spiral portion 25.
The heating value per unit volume obtained by dividing the heating value of Joule heat of the heater wire 23 existing within the length L of the heater wire 23 by the volume surrounded by the length L of the spiral portion 25 and the outer diameter D is 8.5 W / cm.
Defrosting of the evaporator 10 is performed at less than ³ . Here, the surface temperature of the heater wire 23 rises as the calorific value per unit volume of the spiral portion 25 increases, and when the calorific value per unit volume exceeds 8.5 W / cm ³ , it is equal to or higher than the ignition temperature of the flammable refrigerant. Becomes

From the above, when the defrosting ability and the service life equivalent to or higher than those in the past can be secured, the heater wire 23 can be kept below the ignition temperature of the combustible refrigerant, and when the combustible refrigerant leaks into the atmosphere of the defrosting means 18. Even if defrosting is performed, the risk of ignition can be reduced. Further, even when the outer diameter D of the spiral portion changes, the calorific value with respect to the volume calculated from the outer diameter D and the length L of the spiral portion 25 is 8.5 W / cm ^3.
Since the heater wire 23 can be set below the ignition temperature of the flammable refrigerant without affecting the outer diameter D of the spiral portion 25 of the heater wire 23 by designing the defrosting to be less than the ignition temperature of the flammable refrigerant. The means 18 can be designed more easily, and the outer diameter D of the spiral portion 25 and the total heat generation amount of the heater wire 23 can be freely changed while maintaining the temperature below the ignition temperature of the flammable refrigerant.

In the present embodiment, isobutane is used as the type of flammable refrigerant, but other flammable refrigerants having the same ignition temperature as isobutane have the same effect.

(Seventh Embodiment) A seventh embodiment according to the present invention will be described with reference to the drawings. The same components as those in the second embodiment will be assigned the same reference numerals and detailed description thereof will be omitted.

FIG. 9 is a cross-sectional view of the essential parts of the seventh embodiment of the present invention, and FIG. 10 is a temperature characteristic diagram of the same embodiment.

As shown in FIG. 9, P is the spiral portion 25.
Is the pitch. Also, as shown in FIG. 10, Q on the horizontal axis
Is the heater wire 2 existing within the length L of the spiral portion 25
3 is the calorific value per unit surface area obtained by dividing the calorific value of Joule heat by its surface area, and is further divided by the coefficient obtained by dividing the pitch P by the outer diameter D, and the vertical axis is the surface temperature of the heater wire 23. Is.

The operation of the freezer-refrigerator constructed as above will be described below.

During defrosting, the defrosting means 18 has a calorific value Q of 9.2.
Defrosting of the evaporator 10 is performed at less than W / cm ² . Here, the surface temperature of the heater wire 23 rises as the calorific value Q increases, and when the calorific value Q exceeds 9.2 W, the surface temperature becomes higher than the ignition temperature of the flammable refrigerant.

Therefore, when the heater wire 23 can be kept below the ignition temperature of the combustible refrigerant while ensuring the defrosting capacity and life equivalent to or more than those of the conventional case, and the combustible refrigerant leaks into the atmosphere of the defrosting means 18, Even if defrosting is performed, the risk of ignition can be reduced. Furthermore, the pitch P of the spiral part 25
And when the diameter D changes, the calorific value Q is 9.2.
By designing it so that it is less than W / cm ^{2, the} heater wire 23 does not affect the pitch and diameter of the spiral part 25.
Is less than the ignition temperature of the flammable refrigerant, the defrosting means 18 can be more easily designed to be less than the ignition temperature of the flammable refrigerant, and the pitch of the spiral part 25 while maintaining the ignition temperature of the flammable refrigerant below the ignition temperature. The diameter and the total calorific value of the heater wire 23 can be freely changed.

In the present embodiment, isobutane is used as the type of flammable refrigerant, but other flammable refrigerants having the same ignition temperature as isobutane have the same effect.

(Embodiment 8) Embodiment 8 of the present invention will be described with reference to the drawings. The same components as those in Embodiments 2 to 7 will be assigned the same reference numerals and detailed description thereof will be omitted.

FIG. 11 is a sectional view of the essential parts of the eighth embodiment of the present invention.

As shown in FIG. 11, the pitch of the spiral portions 25 is 2 mm.

The operation of the refrigerator-refrigerator constructed as above will be described below.

When the defrosting means 18 is activated and the heater wire 23 is energized, the spiral portion 25 is affected by the heater wires 23 adjacent to each other and the temperature thereof rises. At this time, the temperature of each part of the spiral part 25 varies due to the influence of adjacent lines changing due to the variation in the pitch during processing. However, since the pitch of the spiral portions 25 is 2 mm or more, the influence from the lines adjacent to each other is reduced and the variation can be suppressed.

From this, the temperature variation due to the variation in the pitch of the spiral portion 25 can be reduced, so that the entire heater wire 23 can be kept below the ignition temperature of the flammable refrigerant,
Even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, the risk of ignition can be further reduced.

In this embodiment, the pitch is 2 mm, but if it is more than that, the same or more effect can be obtained.

(Ninth Embodiment) A ninth embodiment according to the present invention will be described with reference to the drawings. The same components as those in Embodiments 2 to 8 are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 12 is a wiring diagram of essential parts in the ninth embodiment of the present invention.

As shown in FIG. 12, 28 is a metal that melts at a predetermined temperature lower than the ignition temperature of the flammable refrigerant, and 29 is a power source.

The operation of the refrigerator-refrigerator constructed as above will be described below.

At the time of defrosting, energization of the heater wire 23 of the defrosting means 18 is started from the power source 29. Then, when a high voltage is applied due to a large voltage fluctuation, the surface temperature of the heater wire 23 may become higher than the ignition temperature of the flammable refrigerant. At this time, when the heater wire 23 reaches a predetermined temperature lower than the ignition temperature of the flammable refrigerant, the temperature is transferred to the metal 28, the metal 28 melts, and the power supply 29 is cut off from the heater wire 23, so that the heater wire 23 generates heat. Disappears and the temperature drops.

From this fact, the combustible refrigerant is the defrosting means 18
Even if defrosting is performed when it leaks to the atmosphere, the risk of ignition can be reduced.

(Tenth Embodiment) A tenth embodiment of the present invention will be described with reference to the drawings. In addition,
The same components as those in the first to ninth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 13 is a wiring diagram of essential parts in the tenth embodiment of the present invention.

As shown in FIG. 13, reference numeral 30 is a thermal fuse made of metal that melts at a predetermined temperature lower than the ignition temperature of the flammable refrigerant.

The operation of the freezer-refrigerator constructed as above will be described below.

When a high voltage is applied due to a large voltage fluctuation, the surface temperature of the heater wire 23 may exceed the ignition temperature of the flammable refrigerant. At this time, the defrosting means 18
When the temperature reaches a predetermined temperature lower than the ignition temperature of the flammable refrigerant, the temperature fuse 30 melts, the input from the power source 29 to the defrosting means 18 is cut off, and the temperature of the defrosting means 18 does not rise.

Therefore, the heater wire 23 is suppressed from rising in temperature above the ignition temperature of the flammable refrigerant, and even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, there is a risk of ignition. In addition to the low temperature, the temperature fuse 30 is damaged due to some influence, and when the defrosting means 18 has no problem, only the temperature fuse 30 needs to be replaced, which facilitates maintenance.

(Eleventh Embodiment) An eleventh embodiment of the present invention will be described with reference to the drawings. In addition,
The same components as those in the first to ninth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 14 is a wiring diagram of essential parts in the eleventh embodiment of the present invention.

As shown in FIG. 14, reference numeral 30 is a thermal fuse made of metal that melts at a predetermined temperature lower than the ignition temperature of the flammable refrigerant.

The operation of the refrigerator-refrigerator constructed as above will be described below.

When the defrosting means 18 is activated, the thermal fuse 3 is provided on the outer surface of the defrosting means 18, which is a portion that comes into contact with the gas in the refrigerator.
0 is installed closely. When a high voltage is applied due to large voltage fluctuation, the surface temperature of the heater wire 23 may be higher than the ignition temperature of the flammable refrigerant.

At this time, when the outer surface of the defrosting means 18 reaches a predetermined temperature lower than the ignition temperature of the flammable refrigerant, the heat is satisfactorily transferred to the temperature fuse 30 closely attached, and the temperature of the temperature fuse 30 also ignites the flammable refrigerant. It melts at a predetermined temperature below the temperature and becomes a liquid, which drops. Then, the input to the defrosting means 18 is cut off at the portion of the temperature fuse 30, and the defrosting means 18
The temperature rise of is stopped.

From this fact, the temperature of the portion of the defrosting means 18 that comes into contact with the internal gas can be transmitted to the temperature fuse 30 more accurately, so that the defrosting means 18 will reach the ignition temperature of the flammable refrigerant before it reaches the ignition temperature. The temperature rise can be suppressed more accurately, the risk of ignition can be further reduced even if defrosting is performed when flammable refrigerant leaks into the atmosphere of the defrosting means 18, and the defrosting means 18 has a problem. Thermal fuse 30 without
Is easy to maintain.

(Twelfth Embodiment) A twelfth embodiment of the present invention will be described with reference to the drawings. In addition,
The same components as those in the first to ninth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 15 is a wiring diagram of essential parts in the twelfth embodiment of the present invention.

As shown in FIG. 15, the thermal fuse 30 is installed above the outer shell of the defrosting means 18.

The operation of the refrigerator-refrigerator constructed as above will be described below.

When the defrosting means 18 is activated, the defrosting means 18 is heated to heat the gas in the vicinity of the outer periphery and move upward, so that the defrosting means 18 has a high temperature part in the upper part with respect to the lower part.
Then, when a high voltage is applied due to a large voltage fluctuation, the surface temperature of the heater wire 23 may become higher than the ignition temperature of the flammable refrigerant. At this time, when the high temperature portion of the defrosting means 18 reaches a predetermined temperature lower than the ignition temperature of the flammable refrigerant, the temperature fuse 30 is melted and the input to the defrosting means 18 is cut off to suppress the temperature rise.

From this, the temperature fuse 30 operates by detecting the temperature of the upper part, which is a high temperature portion, in the vertical direction of the defrosting means 18, so that the temperature of the defrosting means 18 is equal to or higher than the ignition temperature of the combustible refrigerant. Of the defrosting means 18 can be further suppressed, the risk of ignition can be further reduced even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, and there is no problem in the defrosting means 18. Maintenance of the thermal fuse 30 is easy.

(Thirteenth Embodiment) The thirteenth embodiment of the present invention will be described with reference to the drawings. In addition,
The same components as those in the first to ninth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 16 is a wiring diagram of essential parts in the thirteenth embodiment of the present invention.

As shown in FIG. 16, the thermal fuse 30 is installed below the outer shell of the defrosting means 18.

The operation of the freezer-refrigerator constructed as above will be described below.

During defrosting, the frost melted from the evaporator 10 and the like above the defrosting means 18 becomes defrosting water, and part of the defrosting means 18
Others are dropped directly into the tub 13. The defrosting water dropped on the defrosting means 18 comes into contact with the upper part of the defrosting means 18 and evaporates, and the temperature fuse 3 located under the defrosting means 18
It rarely drops to 0.

From the above, when the surface temperature of the heater wire 23 becomes equal to or higher than the ignition temperature of the flammable refrigerant when a high voltage is applied due to a large voltage fluctuation, the temperature fuse 30 is placed above the defrosting means 18. Since there is no temperature drop due to direct contact with the defrosting water dropped from a certain evaporator 10 or the like, the temperature of the defrosting means 18 can be accurately detected, and the temperature rise above the ignition temperature of the defrosting means 18 is more accurate. And the risk of ignition can be further reduced even if defrosting is performed when flammable refrigerant leaks into the atmosphere of the defrosting means 18, and the temperature fuse 30 of the temperature fuse 30 when the defrosting means 18 has no problem. It has an effect of easy maintenance.

(Fourteenth Embodiment) A fourteenth embodiment according to the present invention will be described with reference to the drawings. In addition,
The same components as those of the first to thirteenth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 17 is a wiring diagram of essential parts in the fourteenth embodiment of the present invention.

As shown in FIG. 17, the thermal fuse 30 is installed in the outer region near the central portion L / 2 of the length L of the defrosting means 18.

The operation of the refrigerator-refrigerator constructed as above will be described below.

Since both ends of the defrosting means 18 are in contact with the outside air, heat is exchanged with the outside air and the temperature becomes lower than the central part, so that the central part of the defrosting means 18 becomes a high temperature part. Then, when a high voltage is applied due to large voltage fluctuation,
The surface temperature of the heater wire 23 may be higher than the ignition temperature of the flammable refrigerant.

At this time, when the central portion, which is a high temperature portion of the defrosting means 18, reaches a predetermined temperature lower than the ignition temperature of the flammable refrigerant, the temperature fuse 30 closely attached to that portion is melted and blown to the defrosting means 18. The input is cut off to suppress the temperature rise.

From this, the temperature fuse 30 operates by detecting the temperature of the central portion which is a high temperature portion in the length direction of the defrosting means 18, so that the ignition temperature of the flammable refrigerant of the entire defrosting means 18 is detected. When the above temperature rise can be further suppressed, the risk of ignition can be further reduced even if defrosting is performed when flammable refrigerant leaks into the atmosphere of the defrosting means 18, and there is no problem in the defrosting means 18. The maintenance of the temperature fuse 30 is easy.

(Fifteenth Embodiment) A fifteenth embodiment of the present invention will be described with reference to the drawings. In addition,
The same components as those in the tenth to fourteenth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 18 is a sectional view of an essential part in the fifteenth embodiment of the present invention.

As shown in FIG. 18, the temperature fuse 30 has a temperature of 100 to 200 ° C. higher than the ignition temperature of the flammable refrigerant used.
Fuse at a temperature lowered by ℃.

The operation of the refrigerator-refrigerator constructed as above will be described below.

When a high voltage is applied due to large voltage fluctuation, the surface temperature of the heater wire 23 may be higher than the ignition temperature of the flammable refrigerant. At this time, when the heater wire 23, which is a heating element, reaches a predetermined temperature near the ignition temperature of the flammable refrigerant and lower than the ignition temperature, the heater wire 23
The surface of the glass tube 22 around the temperature of the glass tube 22 becomes a predetermined temperature lower by 100 ° C. to 200 ° C. due to the heat taken away when the heat is transferred from the heater wire 23 to the glass tube 22.

Then, the temperature fuse 30 closely attached to the surface of the glass tube 22 is blown to cut off the input to the heater wire 23, thereby suppressing the temperature rise.

From this, in the defrosting means 18 having the heater wire 23 inside the glass tube 22, it is possible to more accurately suppress the temperature rise above the ignition temperature of the entire flammable refrigerant of the defrosting means 18, Even if defrosting is performed when flammable refrigerant leaks to the atmosphere of the defrosting means 18, the risk of ignition can be further reduced, and the maintenance of the thermal fuse 30 when the defrosting means 18 has no problem is easy. is there.

(Embodiment 16) Embodiment 16 of the present invention will be described with reference to the drawings. In addition,
The same components as those of the first to thirteenth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 19 is a sectional view of the essential parts according to the sixteenth embodiment of the present invention.

As shown in FIG. 19, the thermal fuse 30 includes a glass tube 22 on the outer periphery of the straight portion 24 of the heater wire 23.
It is installed on the surface and the glass tube 2
It is closely fixed to 2.

The operation of the refrigerator-refrigerator constructed as above will be described below.

During operation of the defrosting means, the defrosting means 18
The temperature of the heater wire 23 increases due to Joule heat, and heat is transferred to the glass tube 22 on the outer periphery of the heater wire 23, and the temperature of the glass tube 22 also increases in correlation with the heater wire 23.

At this time, the straight line portion 24 of the heater wire 23 is less affected by the adjacent wires like the spiral portion 25, so that the temperature becomes low, and the glass tube 22
Also in, the temperature of the portion on the outer periphery of the straight portion 24 becomes low.

Then, when the heater wire reaches a certain temperature lower than the ignition temperature of the flammable refrigerant, the temperature of the glass tube 22 on the outer periphery of the straight portion 24 reaches a predetermined temperature lower than the temperature of the heater wire 23 and the temperature fuse 30 The metal is melted, the electric current to the heater wire 23 is cut off, and the temperature of the heater wire 23 decreases.

Therefore, the defrosting means 18 can suppress the temperature rise before the ignition temperature of the combustible refrigerant is reached, and when the combustible refrigerant leaks into the atmosphere of the defrosting means 18, the defrosting operation is performed. Even if it is broken, the risk of ignition can be reduced, and the maintenance of the thermal fuse 30 when the defrosting means 18 has no problem is easy.

Further, the thermal fuse 30 is the heater wire 2
Since a low temperature of a portion having a correlation with the temperature of 3 is detected and actuated, an inexpensive one can be used as compared with a high temperature type.

In the present embodiment, the thermal fuse 30 is installed in the cap 26 portion because the cap 26 also serves as a holder for the thermal fuse 30, but the heater wire 23 has a straight line. It goes without saying that the same effect can be obtained if it is installed on the surface of the glass tube 22.

(Embodiment 17) Embodiment 17 of the present invention will be described with reference to the drawings. In addition,
The same configurations as those of the first to sixteenth embodiments are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 20 is a sectional view of the essential parts according to the seventeenth embodiment of the present invention.

As shown in FIG. 20, 31 is a temperature detecting means, and when the temperature detecting means detects a predetermined temperature, the power source 29
De-energizes the heater wire 23 of the defrosting means 18.

The operation of the refrigerator-freezer thus constructed will be described below.

During the operation of the defrosting means, the defrosting means 18
The temperature of the heater wire 23 increases due to Joule heat, and heat is transferred to the glass tube 22 on the outer periphery of the heater wire 23, and the temperature of the glass tube 22 also increases in correlation with the heater wire 23.

At this time, since the linear portion 24 of the heater wire 23 is less affected by the mutually adjacent wires like the spiral portion 25, the temperature becomes low and the glass tube 22
Also in, the temperature of the portion on the outer periphery of the straight portion 24 becomes low.

Then, when the heater wire reaches a certain temperature lower than the ignition temperature of the flammable refrigerant, the temperature of the glass tube 22 on the outer periphery of the straight portion 24 reaches a predetermined temperature lower than the temperature of the heater wire 23, and the temperature detecting means 31 Detects the predetermined temperature and shuts off the power supply to the heater wire 23, and the temperature of the heater wire 23 decreases.

From this, the defrosting means 18 can suppress the temperature rise before the ignition temperature of the combustible refrigerant is reached, and when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, defrosting is performed. Even if it is broken, the risk of ignition can be reduced. Further, since the temperature detecting means 31 detects a low temperature in a portion having a correlation with the temperature of the heater wire 23, it is possible to use an inexpensive one as compared with a high temperature one.

In this embodiment, the temperature detecting means is installed in the cap 26 portion because the cap 26 also serves as the holder of the temperature detecting means 31, but the heater wire 23 is used.
It is needless to say that the same effect can be obtained if it is installed on the surface of the glass tube 22 at the outer periphery of the portion where is straight.

(Embodiment 18) An embodiment 18 of the invention will be described with reference to the drawings. In addition,
The same components as in the seventeenth embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 20 is a sectional view of the essential parts according to the eighteenth embodiment of the present invention.

As shown in FIG. 20, 31 is a temperature detecting means, and the temperature detecting means is 310 which is the ignition temperature of the flammable refrigerant.
A temperature lower than ℃ to 410 ℃ is detected, and when the temperature is reached, the power supply 29 shuts off the power supply to the heater wire 23 of the defrosting means 18.

The operation of the refrigerator-refrigerator constructed as above will be described below.

During operation of the defrosting means, the defrosting means 18
The temperature of the heater wire 23 increases due to Joule heat, and heat is transferred to the glass tube 22 on the outer periphery of the heater wire 23, and the temperature of the glass tube 22 also increases in correlation with the heater wire 23.

At this time, in the heater wire 23, the straight line portion 24 is less affected by the mutually adjacent wires like the spiral portion 25, so that the temperature becomes low and the glass tube 22
Also in, the temperature of the portion on the outer periphery of the straight portion 24 becomes low.

When the heater wire reaches a temperature near the ignition temperature of the flammable refrigerant, the temperature of the glass tube 22 on the outer periphery of the straight portion 24 thereby reaches a temperature lower by 310 to 410 ° C. At that time, the temperature detecting means 31 detects the temperature and shuts off the energization to the heater wire 23, and the temperature of the heater wire 23 decreases without reaching the ignition temperature of the flammable refrigerant.

Therefore, the defrosting means 18 can accurately suppress the temperature rise before the ignition temperature of the flammable refrigerant is reached, and when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, the defrosting operation is performed. The risk of ignition can be further reduced even if the operation is performed, and the temperature detecting means 31 detects the low temperature of the portion that correlates with the temperature of the heater wire 23, so that a cheaper one can be used as compared with the high temperature one. .

(Embodiment 19) Embodiment 19 of the present invention will be described with reference to the drawings. In addition,
The same configurations as those of the first to eighteenth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 21 is a sectional view of the essential parts according to the nineteenth embodiment of the present invention.

As shown in FIG. 21, 32 is a glass tube 22.
Is the inner surface of the glass tube, 33 is the outer surface of the glass tube 22, and L is the length of the spiral portion 25.

The operation of the refrigerator-refrigerator constructed as above will be described below.

During defrosting, the heater wire 23 is energized through the lead wire 27, and the heater wire 23 generates Joule heat. At this time, the defrosting means 18 has the spiral part 25.
When the Joule calorific value per surface area of the inner surface 32 of the glass tube in the length L is less than the predetermined value, the evaporator 10 is defrosted.

Here, the surface temperature of the heater wire 23 increases as the calorific value per unit area, which is Joule heat with respect to the surface area of the glass tube inner surface 32, increases, and when the calorific value per unit area exceeds a predetermined value. The temperature is above the ignition temperature of the flammable refrigerant. That is, unless the glass tube 22 is designed to have an area of the inner surface 32 of the glass tube that is suitable for the amount of heat generated by the heater wire 23, the amount of heat radiated from the heater wire 23 to the outside through the glass tube 22 is reduced and the defrosting ability is reduced. And the temperature of the heater wire 23 rises.

Therefore, by setting the calorific value per unit area, which is Joule heat of the heater 23, with respect to the surface area of the inner surface 32 of the glass tube to be less than a predetermined value, the decrease in the heat transfer rate due to the temperature decrease of the glass tube 22 can be expressed in the heat transfer area. Can be compensated for, while maintaining the same amount of heat radiation from the glass tube 22 as before,
The temperature of the glass tube 22 which is correlated with the temperature of the heater wire 23 can be lowered.

From the above, it is possible to keep the heater wire 23 below the ignition temperature of the combustible refrigerant while ensuring the defrosting ability and life equivalent to or higher than those of the conventional case, and when the combustible refrigerant leaks into the atmosphere of the defrosting means 18. Even if defrosting is performed, the risk of ignition can be reduced.

Further, if the total calorific value of the heater wire 23 is increased, the surface temperature of the heater wire 23 rises, but even if the total calorific value is increased, the calorific value per unit area of the inner surface 32 of the glass tube is less than a predetermined value. By designing so that the heater wire 23 is independent of the total heat generation amount of the heater wire 23,
Is less than the ignition temperature of the flammable refrigerant, the defrosting means 18 can be easily designed to be less than the ignition temperature of the flammable refrigerant, and the total calorific value of the heater wire 23 can be maintained below the ignition temperature of the flammable refrigerant. Can be increased.

(Embodiment 20) Embodiment 20 of the present invention will be described with reference to the drawings. In addition,
The same components as those of the nineteenth embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

FIG. 21 is a sectional view of the essential parts of the twentieth embodiment of the present invention, and FIG. 22 is a temperature characteristic diagram of the same embodiment.

As shown in FIGS. 21 and 22, the horizontal axis represents the amount of Joule heat of the heater wire 23 existing within the length L of the spiral portion 25 within the glass tube corresponding to the length L of the spiral portion 25. The heat generation amount per unit surface area of the inner surface of the glass tube divided by the surface area of the surface 32, and the vertical axis represents the surface temperature of the heater wire 23. The refrigerant of the refrigeration cycle is isobutane.

The operation of the refrigerator-refrigerator constructed as above will be described below.

At the time of defrosting, the heater wire 23 is energized through the lead wire 27, and the heater wire 23 generates heat by Joule heat. At this time, the defrosting means 18 has the spiral part 25.
The evaporator 10 is defrosted with a calorific value of less than 1.6 W / cm ² of Joule calorific value per surface area of the inner surface 32 of the glass tube existing in the length L of.

The surface temperature of the heater wire 23 increases as the calorific value per unit area, which is Joule heat with respect to the surface area of the glass tube inner surface 32, increases, and the calorific value per unit area is 1.6 W / cm. ^{When it is 2} or more, it becomes the ignition temperature of the flammable refrigerant or more.

That is, unless the glass tube 22 is designed so as to have an area of the inner surface 32 of the glass tube that is suitable for the amount of heat generated by the heater wire 23, the glass tube 22 is separated from the heater wire 23.
Through this, the amount of heat radiated to the outside is reduced, the defrosting capability is reduced, and the temperature of the heater wire 23 rises.

Therefore, the amount of heat generated per unit area, which is Joule heat of the heater 23 with respect to the surface area of the inner surface 32 of the glass tube, is set to less than 1.6 W / cm ^2.
The decrease in the amount of heat transfer due to the decrease in temperature can be compensated by the heat transfer area, and the temperature of the glass tube 22 that correlates with the temperature of the heater wire 23 can be maintained while maintaining the same amount of total heat dissipation from the glass tube 22 as before. Can be lowered.

From the above, when the defrosting ability and the service life equivalent to or higher than those of the prior art can be secured, the heater wire 23 can be kept below the ignition temperature of the flammable refrigerant, and when the flammable refrigerant leaks into the atmosphere of the defrosting means 18. Even if defrosting is performed, the risk of ignition can be reduced. Further, if the total calorific value of the heater wire 23 is increased, the surface temperature of the heater wire 23 rises,
By designing the heat generation amount per unit area of the inner surface 32 of the glass tube to be less than 1.6 W / cm ² even if the total heat generation amount is increased, the heater wire 23 is irrelevant regardless of the total heat generation amount. Is less than the ignition temperature of the flammable refrigerant, the defrosting means 18 can be easily designed to be less than the ignition temperature of the flammable refrigerant, and the total calorific value of the heater wire 23 can be maintained below the ignition temperature of the flammable refrigerant. Can be increased.

In the present embodiment, the temperature of the heater wire 23 is lower than the ignition temperature of isobutane. However, when an isobutane refrigerant is used, it is safe with respect to the ignition temperature of isobutane of about 460 ° C. In consideration of the rate, it is necessary to set the temperature of the heater wire 23 to 360 ° C. or less. In this case, the calorific value per unit surface area of the glass tube is set to 0.67 W / cm ² or less.

(Twenty-first Embodiment) A twenty-first embodiment of the present invention will be described with reference to the drawings. In addition,
The same configurations as those of the first to the twentieth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 23 is a sectional view of the essential parts according to the twenty-first embodiment of the present invention.

As shown in FIG. 23, 34 is the glass tube 22.
The air in the tube which is the gas inside, D is the outer diameter of the spiral portion 25 of the heater wire 23, d is the inner diameter of the glass tube 22, and the outer peripheral portion of the spiral portion 25 of the heater wire 23 and the inner surface 32 of the glass tube. The distance is 1 mm.

The operation of the freezer-refrigerator constructed as above will be described below.

At the time of defrosting, the heat radiated from the surface of the heater wire 23 of the defrosting means 18 passes through the layer 1 mm of the air 34 having a low heat conductivity between the heater wire 23 and the inner surface of the glass tube 22 into the glass tube. Glass tube 2 through the wall thickness of 22
Heat is radiated to the outside from the outer surface of 2. Therefore, by reducing the layer of the air 34 in the tube having a low thermal conductivity to 1 mm, heat transfer from the heater wire 23 to the inner surface 22 of the glass tube is promoted, heat dissipation to the outside is promoted, and defrosting is promoted. The surface temperature of the line 23 decreases.

Further, due to the tolerance of the inner diameter d of the glass tube 22 and the tolerance of the outer diameter D of the spiral portion 25 of the heater wire 23, it is easy to work when inserting the heater wire 23 into the glass tube 22 during manufacturing. You can

From the above, the workability in manufacturing can be maintained at the same level as before, and the heater wire 23 can be kept below the ignition temperature of the flammable refrigerant while maintaining the defrosting ability and life equivalent to or better than the conventional level. Even if defrosting is performed when the refrigerant leaks into the atmosphere of the defrosting means 18, the risk of ignition can be further reduced.

In the present embodiment, the distance between the outer peripheral portion of the spiral portion 25 of the heater wire 23 and the inner surface 32 of the glass tube 22 is 1 mm, but if it is less than that, the same or more advantageous effects can be obtained. Although the gas in the glass tube 22 is air, the same effect can be obtained as long as it has poor thermal conductivity.

Further, in the present embodiment, the temperature of the heater wire 23 is set to be lower than the ignition temperature of the flammable refrigerant, but specifically isobutane is used as the refrigerant, and the safety factor is set to prevent ignition. Expect heater wire 23 to 36
In order to keep the temperature below 0 ° C., the distance between the outer peripheral portion of the spiral portion 25 of the heater wire 23 and the inner surface 32 of the glass tube 22 is set to 1
mm or less, the Joule calorific value to the surface area of the heater wire 23 is 0.67 W / cm ² or less,
In addition, by setting the Joule calorific value of the heater wire 23 to 0.67 W / cm ² or less with respect to the inner surface area of the glass tube, the temperature of the heater wire 23 can be more effectively set to 360 ° C or less.

(Embodiment 22) Embodiment 22 of the present invention will be described with reference to the drawings. In addition,
The same configurations as those of the first to the twentieth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 24 is a sectional view of the essential parts according to the twenty-second embodiment of the present invention.

As shown in FIG. 24, the spiral portion 25 of the heater wire 23 and the inner surface 32 of the glass tube are in contact with each other.

The operation of the refrigerator-freezer thus constructed will be described below.

During defrosting, part of the heat radiated from the surface of the heater wire 23 of the defrosting means 18 is the inner surface 3 of the glass tube.
2 is transmitted to the glass tube 22 through the contact surface with the glass tube 22, and is radiated to the outside from the glass tube outer surface 33, and the others are transmitted through the tube inner air 34 from the glass tube inner surface 32 through the glass tube 22 inside to the glass tube outer surface 33. Radiated from.

At this time, since the glass tube 22 has very good heat conduction as compared with the air 34 in the tube, the heat transfer is promoted by the contact between the heater wire 23 and the inner surface 32 of the glass tube.
The amount of heat radiated from the heater wire 23 increases to promote defrosting, and the temperature of the heater wire 23 decreases.

From the above, when the defrosting ability and the service life equivalent to or higher than those of the prior art can be secured, the heater wire 23 can be kept below the ignition temperature of the flammable refrigerant, and when the flammable refrigerant leaks into the atmosphere of the defrosting means 18. Even if defrosting is performed, the risk of ignition can be reduced.

(Embodiment 23) Embodiment 23 of the present invention will be described with reference to the drawings. In addition,
The same components as those in the first to the twenty-first embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 25 is a horizontal cross-sectional view of the essential parts of the twenty-third embodiment of the present invention, and FIG. 26 is a vertical cross-sectional view showing a cross section of a glass tube.

As shown in FIGS. 25 and 26, the defrosting means 1
8 is provided with a roof 16 above a glass tube 22 in which a heater wire 23 is installed. The shape of the roof 16 is U-shaped, and the edges on both sides of the U-shaped are 35, and the U-shaped. Is installed so that the opening of the is located below. Further, J is a predetermined value of the dimension of the shortest distance portion between the roof 16 and the outer surface 33 of the glass tube, and the arrow indicates the path of convection air.

The operation of the refrigerator-refrigerator constructed as above will be described below.

At the time of defrosting, the outer surface 33 of the glass tube is heated by the heat generated by the heater wire 23, is transferred to the surrounding air, and the temperature rises and moves upward by convection. Then, the U-shape of the roof 16 is filled, and the overflow from the edge 35 is reflected in the roof 16.
To defrost the evaporator 10 and its peripheral parts. The water that has been defrosted and liquefied drops on the upper part of the roof 16,
It is dropped below the defrosting means 18 along the U-shaped edge 35 without dropping on the glass tube 22.

At this time, the roof 16 is above the glass tube 22.
The temperature rises because it is exposed to the hot air in the U-shape, and the temperature of the upper portion of the heater wire 23 also rises. Therefore, by opening the distance between the roof 16 and the glass tube 22 by a predetermined value J or more, there is no portion where the high temperature air filled in the U-shape of the roof 16 comes into contact with the glass tube 22, so that the temperature of the glass tube 22 decreases. However, the temperature of the heater wire 23 also decreases accordingly.

From the above, when the defrosting ability and the service life which are equal to or higher than those of the prior art can be secured, the heater wire 23 can be kept below the ignition temperature of the flammable refrigerant, and when the flammable refrigerant leaks into the atmosphere of the defrosting means 18. Even if defrosting is performed, the risk of ignition can be reduced.

(Embodiment 24) Embodiment 24 of the present invention will be described with reference to the drawings. In addition,
The same components as those in Embodiments 1 to 23 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 27 is a sectional view of the essential portions according to the twenty-fourth embodiment of the present invention.

As shown in FIG. 27, the wall thickness of the glass tube 22 is 1.0 mm.

The operation of the refrigerator-refrigerator constructed as above will be described below.

At the time of defrosting, the heat generated from the heater wire 23 is radiated from the inner surface 32 of the glass tube to the outer surface 33 of the glass tube through the wall thickness of the glass tube 22 to defrost the peripheral parts of the defrosting means 18. To do. At this time, since the thickness of the glass tube 22 is 1.0 mm, the amount of heat radiated from the heater wire 23 through the glass tube 22 is increased due to the promotion of heat transfer of the glass tube 22 while maintaining the strength of the glass tube 22. As the frost is promoted, the temperature of the heater wire 23 decreases.

Therefore, when the heater wire 23 can be kept below the ignition temperature of the combustible refrigerant while securing the defrosting ability and the life equivalent to or more than those of the conventional case, and the combustible refrigerant leaks into the atmosphere of the defrosting means 18, Even if defrosting is performed, the risk of ignition can be reduced.

In this embodiment, the thickness of the glass tube 22 is 1.0 mm, but if the thickness is 1.5 mm or less, the same effect can be obtained although the degree of effect is different.

(Embodiment 25) Embodiment 25 of the present invention will be described with reference to the drawings. In addition,
The same configurations as those in the first to twenty-fourth embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 27 is a sectional view of the essential parts according to the twenty-fifth embodiment of the present invention.

As shown in FIG. 27, the material of the glass tube 22 is quartz.

The operation of the refrigerator-refrigerator constructed as above will be described below.

Before and after defrosting, the refrigerant flows through the evaporator 10 for cooling the freezer compartment 2 and the refrigerator 3 of the refrigerator body 1, and the glass tube 22 of the defrosting means 18 located around the evaporator 10 is minus. It becomes temperature. And, at the time of defrosting, the defrosting means 18
The heating of the heater wire 23 causes the glass tube to be heated and the temperature rises to a high temperature in a short time, and the temperature of the glass tube 22 varies from 300 to 450 ° C. in a short time.

At this time, the conventional glass tube may be damaged due to the difference in linear expansion, and when decompressing is performed when the combustible refrigerant leaks to the atmosphere of the defrosting means 18 in the damaged state, the combustible refrigerant is removed. There is a risk of fire.

However, since the quartz glass has a small linear expansion due to temperature fluctuation and is not damaged, even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means 18, there is a higher risk of ignition. Can be lowered.

(Twenty-sixth Embodiment) A twenty-sixth embodiment of the present invention will be described with reference to the drawings. In addition,
The same configurations as those of the second to 25th embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 28 is a diagram showing a refrigerating system in Embodiment 26 of the present invention, and FIG. 29 is Embodiment 2 of the present invention.
It is sectional drawing of the refrigerator in FIG.

As shown in FIGS. 28 and 29, reference numeral 36 is a refrigerator cooler having a high evaporation temperature for refrigeration, 37 is a high evaporation temperature depressurizing mechanism with a small depressurization amount for high evaporation temperature, and 38 is a refrigerating machine. Cooler for the freezing room having a low evaporation temperature for use, 39 is a decompression mechanism for the low evaporation temperature with a large decompression amount for the low evaporation temperature, 40 is a switching valve for switching the flow path of the refrigerant, 41 is the compressor 19 or the refrigerating room It is a check valve for preventing the reverse flow of the refrigerant from the cooling device 36 for the freezer to the cooling device 38 for the freezer compartment.

Reference numeral 42 indicates the air in the refrigerating compartment 3 for the refrigerating compartment cooler 3.
A fan for a refrigerating compartment for ventilating 6 to exchange heat to circulate the cooling air, and a refrigerating compartment 43 for ventilating the air in the freezing compartment 2 to the cooler 38 for the freezing compartment to circulate the cooling air. A cooling fan partition wall 44, which is a duct for preventing heat transfer from the refrigerating compartment cooler 36 to the refrigerating compartment 3 and also serving as a duct for smoothly ventilating the refrigerating compartment cooler 36, and 45 A refrigerating compartment discharge port through which cold air that has exchanged heat with the refrigerating compartment cooler 36 is discharged to the refrigerating compartment 3 by the operation of the refrigerating compartment fan 42, and 46 constitutes a duct for smoothly ventilating the freezer compartment cooler 38. Freezer compartment cooler partition wall, 47
Is operated by the freezer compartment fan 43 to operate the freezer compartment cooler 38.
The freezing room discharge port for discharging the cold air that has exchanged heat with the freezing room 2,
Reference numeral 48 is an evaporating dish for storing and automatically evaporating defrost water generated when the freezer compartment cooler 38 is defrosted.

Regarding the refrigerator configured as described above,
The operation will be described below.

When the refrigerating compartment 3 is cooled, when the refrigerating compartment 3 reaches a certain set temperature or higher, the compressor 19 is activated, circulation of a flammable refrigerant (not shown) in the refrigeration cycle is started, and the flammable refrigerant is condensed in the condenser. It is condensed by heat exchange with the outside air at 20,
The switching valve 40 serves as a refrigerating compartment cooling refrigeration cycle in which the refrigerant flows through the high evaporation temperature depressurizing mechanism 37 to the refrigerating compartment cooler 36 and is sucked into the compressor 19.

At this time, the refrigerator room fan 42 operates simultaneously with the operation of the compressor 19, so that the air in the refrigerating room 3 is sucked from the refrigerating room inlet port 8 and is passed through the refrigerating room cooler 36 to exchange heat. The cooled air is discharged from the refrigerating compartment discharge port 45 into the refrigerating compartment 3 to cool the refrigerating compartment 3.

[0217] Further, at any time while the compressor 19 is stopped, the refrigerating compartment fan 42 is operated and the refrigerating compartment 3 is cooled to 0 ° C.
After passing through the refrigerating-room cooler 36, the frost that has frosted on the refrigerating-room cooler 36 by the ventilated air is defrosted by sublimation and also passes through the refrigerating-room cooler 36. The air of which the absolute humidity is increased is discharged to the refrigerator compartment 3.

When the freezer compartment 2 is cooled, when the freezer compartment 2 reaches a certain set temperature or higher, the compressor 19 is activated, circulation of the flammable refrigerant in the refrigeration cycle is started, and the combustible refrigerant is condensed in the condenser 20. It is condensed by heat exchange with the outside air, and the switching valve 40
Thus, the refrigerating chamber cooling refrigeration cycle is such that it flows through the low evaporation temperature depressurizing mechanism 39 to the freezing chamber cooler 38 and is sucked into the compressor 19.

When the freezer compartment fan 43 is operated simultaneously with the operation of the compressor 19, the air in the freezer compartment 2 is sucked from the freezer compartment inlet 7, and the freezer compartment cooler 38 is ventilated for heat exchange. The air thus formed is discharged from the freezing compartment discharge port 47 into the freezing compartment 2 to cool the freezing compartment 2. At this time, since the air passing through the freezer compartment cooler 38 is the air only from the freezer compartment 2, the freezer compartment cooler 38 is small and has a small heat exchange area. Less.

Further, the defrosting means 18 is operated at any time while the compressor 19 is stopped or while the refrigerating room is being cooled, and defrosts the freezing room cooler 38 and its peripheral parts. At this time, the refrigerant in the piping of the freezer compartment cooler 38 is also heated. Then, the heated refrigerant evaporates in the freezer compartment cooler 38 and moves to the low temperature portion which is not yet heated by the defrosting means 18, and removes heat from the frost in that portion.

Then, the frost is melted and the refrigerant is condensed by removing heat from the frost. At this time, a part of the condensed refrigerant remains in the freezer compartment cooler 38 and is heated again by the defrosting means 18. By repeating this operation, the entire cooler for the freezer compartment is defrosted, and the defrosted water that has become defrosted water falls into the tub 13 and drops from the drain port 14 into the evaporation tray 48 and is stored. The defrosted water stored in the evaporation tray 48 receives the heat generated when the compressor 19 is operating and spontaneously evaporates.

As described above, since the freezer compartment cooler 38 cools only the freezer compartment 2, the amount of frost is small, so the defrosting means 1
It is possible to reduce the heat generation amount of No. 8 and to reduce the heat generation amount of the defrosting unit 18
Temperature drops.

Furthermore, in the conventional one cooler, most of the total amount of the refrigerant in the refrigeration cycle exists in the evaporator 10 which is the cooler, and therefore a large amount of heat is needed for the defrosting means 18 during defrosting. A large amount of heat is required, and a large amount of heat is required for the refrigerant in addition to the amount of heat used for defrosting. However, in the present invention, since a part of the refrigerant is present in the refrigerating compartment cooler 36, the amount of the refrigerant in the freezing compartment cooler 38 is much smaller than in the case of one conventional cooler, and defrosting is performed. In addition to defrosting, the amount of heat used by the defrosting unit 18 for heating may be small at some times, thus saving energy.

From the above, the defrosting means 18 can be lowered to a temperature lower than the ignition temperature of the combustible refrigerant while maintaining the defrosting ability equal to or higher than the conventional one, and the combustible refrigerant can be placed in the installation atmosphere of the defrosting means 18. Even when defrosting is performed in a leaked environment, the risk of ignition of the flammable refrigerant can be further reduced.

(Twenty-Seventh Embodiment) A twenty-seventh embodiment of the present invention will be described with reference to the drawings. In addition,
The same components as those in Embodiments 1 to 26 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 30 is a longitudinal sectional view of the essential parts according to the twenty-seventh embodiment of the present invention.

As shown in FIG. 30, reference numeral 49 designates an upper swash plate which is one of the V-shapes of the roof 16 and is located above the roof.
Is a lower swash plate located under the upper swash plate 49, which is the other of the V-shape of the roof 16, and 51 is a gap between the upper swash plate 49 and the lower swash plate 50. The arrow indicates the path of air around the defrosting means.

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

During defrosting, the heater wire 23 of the defrosting means generates heat, and the temperature of the heater wire 23 and the glass tube 22 around the heater wire 23 rises. Then, the air in the vicinity of the glass tube 22 is heated and rises to the upper swash plate 49 and the lower swash plate 50 of the roof 16 as indicated by the arrow, and part of the air moves to the upper evaporator 10 through the gap 51, Defrosting is performed by exchanging heat with the frost attached to the evaporator 10 and its surroundings. Then, the defrosted water is dropped on the upper swash plate 49 and the lower swash plate 50, and is not dropped directly on the glass tube 22.
And fall down.

From this, the defrosting means 18 can be used as in the conventional case.
Since the defrosting water does not drip directly onto the glass tube 22 of No. 1, the air heated by the defrosting means 18 is smoothly evaporated to the conventional roof 16 having no gap 51 while ensuring the same life as the conventional one. Since it can be moved to 10, the amount of heat released to the outside is further increased, the defrosting capacity is further improved, and the amount of the amount of heat released to the outside is increased by the temperature rise of the heater wire 23 of the defrosting means 18. Since the amount of heat used is reduced, the surface temperature of the heater wire 23 is further lowered and can be made lower than the ignition temperature of the flammable refrigerant.

[0231]

As described above, the present invention provides a frozen
Defrost icicle evaporator and frost attached to the evaporator
Heater for defrosting, and enclosed in the refrigeration cycle
The defrosting heater is equipped with a flammable refrigerant
And a spiral part provided inside the glass tube.
A heater wire made of a metal resistor,
-To set the pitch of the spiral part of the wire to 2 mm or more
Therefore, the influence from the heater wires adjacent to each other is reduced.
Suppresses temperature variations, and the heater wire is spy
The calorific value due to Joule heat in the rull part divided by its surface area
The calorific value per unit area is less than 2.5 W / cm2
Therefore, temperature variations due to variations in the pitch of the spiral part
Adjacent to each other in the spiral part because the luck can be reduced
When the influence from the heater wire can be reduced and the defrosting capacity and life equivalent to or better than conventional ones can be secured, the heater wire can be kept below the ignition temperature of the flammable refrigerant, and when the flammable refrigerant leaks to the atmosphere of the defrosting means. Even if defrosting is performed, the risk of ignition can be reduced.

Further, the surface temperature rises when the total heating value of the heater wire is increased, but the heating value per unit area is designed to be less than 2.5 W / cm ² even if the total heating value is increased. By doing so, it is possible to make the heater wire below the ignition temperature of the flammable refrigerant regardless of the heat generation amount of the entire heater wire, so it is possible to easily design the defrosting means to make it below the ignition temperature of the flammable refrigerant, and It is possible to increase the total calorific value of the heater wire while maintaining the temperature below the ignition temperature.

[0233] The evaporator of the refrigeration cycle and the steam
A defrosting heater for defrosting the frost attached to the generator,
With a flammable refrigerant enclosed in the refrigeration cycle,
The defrosting heater is installed inside the glass tube and the glass tube.
Heater composed of a metal resistor having a spiral portion provided
The heater wire and the spiral part of the heater wire
By setting the pitch to 2 mm or more,
Suppresses temperature variations by reducing the influence from the
In addition, the above-mentioned heater wire makes the heat generation amount of the spiral part spiral.
The value divided by the volume surrounded by the outer diameter and the length of the
Since it is less than / cm3, the pitch of the spiral part varies
Spiral because temperature variations due to fluctuations can be reduced
The influence from the heater wire adjacent to each other can be reduced
Can, while securing a conventional equal or defrosting capacity and lifetime,
The heater wire can be set below the ignition temperature of the flammable refrigerant, and even if defrosting is performed when the flammable refrigerant leaks into the atmosphere of the defrosting means, the risk of ignition can be further reduced.

Further, even when the outer diameter D of the spiral portion changes, the heat generation amount with respect to the volume calculated from the outer diameter D of the spiral portion and the length L should be designed to be less than 8.5 W / cm ^3. Since the heater wire can be set below the ignition temperature of the flammable refrigerant without affecting the outer diameter D of the spiral portion, the defrosting means for making the temperature below the ignition temperature of the flammable refrigerant can be more easily designed, and the ignition of the flammable refrigerant can be performed. It is possible to freely change the outer diameter D of the spiral portion and the total calorific value of the heater wire while maintaining the temperature below the temperature.

[0235] Further, the evaporator of the refrigeration cycle and the steam
A defrosting heater for defrosting the frost attached to the generator,
With a flammable refrigerant enclosed in the refrigeration cycle,
The defrosting heater is installed inside the glass tube and the glass tube.
Heater composed of a metal resistor having a spiral portion provided
And a wire corresponding to the length of the spiral part.
The unit area of the heater wire with respect to the inner surface area of the lath tube
By setting the calorific value of less than 1.6 W / cm2,
Heat transfer of glass tube
It can be compensated by the area, and the total heat dissipation from the glass tube is conventionally
While maintaining the same, the gas that correlates with the temperature of the heater wire
The temperature of the lath tube can be lowered, and even if defrosting is performed when flammable refrigerant leaks into the atmosphere of the defrosting means, the risk of ignition can be further reduced.

[0236]

The defrosting means comprises a glass tube and a heater wire made of a metal resistor installed inside the glass tube. Since the thickness of the glass tube is 1.5 mm or less, the strength of the glass tube is maintained. At the same time, the amount of heat radiated from the heater wire through the glass tube due to the promotion of heat transfer of the glass tube is increased to promote defrosting and the temperature of the heater wire is lowered.

From this, it is possible to keep the heater wire below the ignition temperature of the combustible refrigerant while ensuring the defrosting capacity and life equivalent to or better than those in the past, and to defrost the combustible refrigerant when it leaks into the atmosphere of the defrosting means. However, the risk of ignition can be reduced.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of a main part of a refrigerator-freezer according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a main part according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a main part according to a fifth embodiment of the present invention.

FIG. 6 is a characteristic diagram of essential parts according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view of a main part according to a sixth embodiment of the invention.

FIG. 8 is a characteristic diagram of essential parts according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view of a main part according to a seventh embodiment of the present invention.

FIG. 10 is a characteristic diagram of a main part according to the seventh embodiment of the present invention.

FIG. 11 is a sectional view of a main part according to an eighth embodiment of the present invention.

FIG. 12 is a wiring diagram of essential parts according to a ninth embodiment of the present invention.

FIG. 13 is a wiring diagram of essential parts according to the tenth embodiment of the present invention.

FIG. 14 is a wiring diagram of essential parts according to an eleventh embodiment of the present invention.

FIG. 15 is a wiring diagram of essential parts according to a twelfth embodiment of the present invention.

FIG. 16 is a wiring diagram of essential parts according to a thirteenth embodiment of the present invention.

FIG. 17 is a wiring diagram of essential parts according to a fourteenth embodiment of the present invention.

FIG. 18 is a sectional view of a main part according to a fifteenth embodiment of the present invention.

FIG. 19 is a sectional view of a main part according to a sixteenth embodiment of the present invention.

FIG. 20 is a cross-sectional view of the essential parts of the seventeenth and eighteenth embodiments of the present invention.

FIG. 21 is a cross-sectional view of the essential parts of the nineteenth and twentieth embodiments of the present invention.

FIG. 22 is a characteristic diagram of main parts according to the twentieth embodiment of the present invention.

FIG. 23 is a sectional view of a main part according to a twenty-first embodiment of the present invention.

FIG. 24 is a cross-sectional view of a main part according to a twenty-second embodiment of the present invention.

FIG. 25 is a transverse cross-sectional view of the essential parts according to the twenty-third embodiment of the present invention.

FIG. 26 is a vertical cross-sectional view of a main part according to a twenty-third embodiment of the invention.

FIG. 27 is a cross-sectional view of the essential parts of Embodiments 24 and 25 of the present invention.

FIG. 28 is a refrigeration system diagram in Embodiment 26 of the present invention.

FIG. 29 is a sectional view of a refrigerator according to a twenty-sixth embodiment of the present invention.

FIG. 30 is a vertical cross-sectional view of a main part according to a twenty-seventh embodiment of the present invention.

FIG. 31 is a vertical cross-sectional view of a main part of a conventional refrigerator-freezer.

[Explanation of symbols]

1 Refrigerator body 2 Freezer 3 refrigerating room 10 evaporator 16 roof 18 Defrosting means 19 compressor 20 condenser 21 Decompression mechanism 22 glass tube 23 heater wire 24 Straight section 25 spiral part 28 metal 30 thermal fuse 31 Temperature detection means 32 glass tube inner surface 33 glass tube outer surface 36 Refrigerator for refrigerator compartment 37 Decompression mechanism for high evaporation temperature 38 Cooler for freezer 39 Decompression mechanism for low evaporation temperature 40 switching valve 41 Check valve

Front Page Continuation (56) References JP-A-9-61041 (JP, A) JP-A-9-329386 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25D 21 / 08

Claims (4)

(57) [Claims] 1. An evaporator of a refrigeration cycle and the evaporator
Defrost heater for defrosting adhered frost, and the
And a combustible refrigerant enclosed in a freezing cycle.
Frost heater is provided inside the glass tube glass tube
A heater wire made of a metal resistor having a spiral part, and the pitch of the spiral part of the heater wire is 2
Heater wires that are adjacent to each other by setting the thickness to mm or more
Suppresses temperature variations by reducing the effect of
The heater wire has a calorific value of 2.5 per unit area obtained by dividing the calorific value of Joule heat in the spiral part by its surface area.
Leakage of the flammable refrigerant at less than W / cm ²
Refrigerated to reduce the risk of fire if
Warehouse . 2. An evaporator of a refrigeration cycle and the evaporator
Defrost heater for defrosting adhered frost, and the
And a combustible refrigerant enclosed in a freezing cycle.
Frost heater is provided inside the glass tube glass tube
A heater wire made of a metal resistor having a spiral part, and the pitch of the spiral part of the heater wire is 2
Heater wires that are adjacent to each other by setting the thickness to mm or more
Suppresses temperature variations by reducing the effect of
For the heater wire, the value obtained by dividing the heat generation amount of the spiral portion by the volume surrounded by the outer diameter and length of the spiral portion is 8.5 W / cm.
When the flammable refrigerant leaks to less than ³
Refrigerator / refrigerator designed to reduce the risk of fire . 3. An evaporator of a refrigeration cycle and the evaporator
Defrost heater for defrosting adhered frost, and the
And a combustible refrigerant enclosed in a freezing cycle.
The frost heater was provided on the glass tube and inside the glass tube.
A heater wire made of a metal resistor having a spiral part
Consisting of a glass tube corresponding to the length of the spiral part
Emission per unit area of the heater wire with respect to the inner surface area of
By setting the heat quantity to less than 1.6 W / cm2, the glass tube temperature
And the glass tube temperature lowers the glass
The heat transfer area of the glass tube
While ensuring defrosting capacity by supplementing with the increase of
Reduces the risk of ignition if flammable refrigerant leaks
Frozen refrigerator 4. The freezer-refrigerator according to claim 1, wherein the glass tube has a wall thickness of 1.5 mm or less.
Warehouse .