KR20060042186A - Refrigerator - Google Patents

Abstract

An object of the present invention is to provide a refrigerator which can improve safety and efficiency even in defrosting operation of a refrigerator using a flammable refrigerant, and also has excellent reliability.

In the refrigerator provided with the defrosting heater 11 which has the heater wire wound in the coil shape in the glass tube below the cooler 10, it was assumed that the heat dissipation member 16 was provided in the outer periphery of the glass tube. In addition, this heat radiating member 16 shall be provided in the outer periphery of the glass tube which opposes the coil part of a heater wire.

Cooler, heat dissipation member, heat dissipation fin, cold air circulation fan, defrost heater

Description

Refrigerator {REFRIGERATOR}

1 is a longitudinal sectional view of a refrigerator provided with the present invention;

Figure 2 is an enlarged view of the main part of Figure 1;

3 is a cross-sectional explanatory view of the defrost heater of FIG. 2;

4 is an explanatory view of the heat radiation fin in FIG. 3;

FIG. 5 is a cross-sectional explanatory diagram of a defrost heater illustrating an embodiment different from FIG. 3. FIG.

6 is an explanatory view of the heat radiation fin in FIG. 5;

FIG. 7 is an inclination diagram of a heat dissipation fin illustrating an embodiment different from FIG.

8 is a P arrow of FIG.

9 is a cross-sectional explanatory diagram of a defrost heater provided with the present invention.

10 is an explanatory view of a refrigeration cycle having the present invention.

11 is a longitudinal sectional view of a conventional refrigerator.

12 is a cross-sectional explanatory view of FIG.

13 is a longitudinal cross-sectional view of FIG. 11;

<Explanation of symbols for the main parts of the drawings>

6: middle partition wall

7, 8: passage

9: cooler room

10: cooler

11: defrost heater

11a: glass tube

11b: heater wire

11c: straight part

12: cold air circulation fan

13: compartment partition

15: roof

16: heat dissipation fin

18: positioning member

19: lead wire

20: gutter

21: connection member

The present invention relates to a refrigerator having a defrost heater for removing frost attached to a refrigerator of a refrigeration cycle.

As a related art related to a refrigerator having a defrost heater, there is one described in Patent Document 1. In this example, below the cooler, a defrosting tube heater in which the nichrome wire is coiled is covered with a glass tube. A roof is provided between this cooler and the defrosting tubular heater to prevent defrosting water dripping from the cooler from directly contacting the defrosting tubular heater. In addition, between the defrosting tubular heater and the gutter at the bottom thereof, an electrically insulating and held bottom plate is installed to protect the gutter, and when the frost removing heater is broken, the heater wire is suspended to the gutter to damage the gutter. This prevents leakage of water through defrosting water.

In addition, Patent Document 2 discloses a heater wire in a sheath tube filled with an insulating material and sealed in order to reduce the defrost heater temperature to less than or equal to the isobutane ignition temperature of the refrigerant, and removes frost having a heat transfer promotion fin on the outer periphery of the sheath tube. A heater is described.

[Patent Document 1]

Japanese Patent Laid-Open No. 8-54172

[Patent Document 2]

Japanese Patent Laid-Open No. 2000-283635

Hereinafter, the subject in the prior art is described.

11 is a view showing a conventional refrigerator. In Fig. 11, reference numeral 51 denotes a refrigerator body, and the refrigerator body 51 is provided with an intermediate partition wall 56 having a freezer compartment 52 and a refrigerating compartment 53 therein and partitioning therebetween. The front opening part of the freezer compartment 52 is provided with the freezing compartment door 54 which closes this opening part, and the front opening part of the refrigerating compartment 53 is equipped with the refrigerating compartment door 55 which closes this opening part.

The intermediate partition wall 56 includes a passage 57 for returning the cold air heat exchanged with the food in the freezing compartment 52 to a cooler described later, and a passage 58 for returning the cold air heat exchanged with the food in the refrigerating compartment 53 to the cooler. ) Is installed. A cooler chamber 59 communicating with the freezing chamber 52 and the refrigerating chamber 53 via the passage 57 and the passage 58 is provided in the rear portion of the freezing chamber 52, and inside the cooler chamber 59, a cooler ( 60), defrost heater 61, and cold air circulation fan 62. The partition partition 63 which partitions between these chambers is provided between the cooler chamber 59 and the freezer chamber, and the cold partition 120 is formed with the cold air outlet 64. By these structures, the cold air cooled by heat exchange with the cooler 60 is taken out from the cold air blowout port 64 to the freezing chamber 52 by the cold air circulation fan 62.

An aluminum roof 65 is provided between the defrost heater 61 and the cooler 60, and when the frost attached to the cooler 60 is melted by the heat of the defrost heater, the cooler ( This is to prevent the defrost water dripping from 60) from directly splashing on the defrost heater.

Usually, in the glass tube 61a of the defrost heater, the surface temperature at the time of heat generation of the defrost heater wire 61b becomes a temperature near 500 degreeC. Dropping water directly on the glass tube results in a vapor explosion state, which generates a loud sound. When the state is close to such a vapor explosion state, the generated sound becomes a sound enough to be heard outside of the refrigerator, which gives anxiety to the user. Preventing this is the role of the roof 65.

An aluminum protective plate 66 is provided below the defrost heater 61, and the protective plate 66 protects the trough 67 when the glass tube 61a is broken by an impact or the like. Fig. 12 shows a state in which the glass tube 61a is broken by an impact or the like, and the heater wire 61b is suspended downward as shown in Fig. 12 so that the heater wire 61b is dropped from the cooler 60. Receives defrost water and prevents contact with resin troughs 67 to help drain out. Since the aluminum protection plate 66 is insulated and hold | maintained, even if the heater wire 61b is suspended by this protection plate 66, electricity does not leak to the metal part of the refrigerator main body 51, and the like.

When the freezing chamber 52 or the refrigerating chamber 53 is cooled, the coolant 60 is cooled by allowing a coolant to flow through the cooler 60. At the same time, the cold air cooled by heat exchange with the cooler 60 by the action of the cold air circulation fan 62 which is operated is taken out from the cold air outlet 64 to the freezing chamber 52. The cold air taken out of the freezer compartment 52 cools the frozen food in the freezer compartment 52 and returns to the cooler 60 and the defrost heater 61 through the passage 57. On the other hand, in the refrigerating chamber 53 side, the cold air cooled by the cooler 60 is taken out by the cold air circulation fan 62 to the refrigerating chamber 53 using the refrigerator exclusive cooling passage although it is not shown in figure. Here too, the food is cooled by heat exchange with the food. The cold air after cooling is returned to the cooler 60 and the defrost heater unit 61 through the passage 58.

The air exchanged with the cooler 60 is highly moistened by inflow of outside air by opening and closing of the freezer compartment door 54 and the refrigerating compartment door 55, or evaporation of moisture contained in food in the freezer compartment 52 and the refrigerating compartment 53. Since it is air that has become cold, the moisture in the cooler 60 becomes frost, and frost is attached and deposited. As the deposition amount increases, heat transfer between the surface of the cooler 60 and the air to be exchanged with the air is inhibited, and at the same time, the airflow resistance is lowered. As a result, the heat passing rate decreases and cooling shortage occurs.

Thus, energization of the defrost heater 61 is started before this lack of cooling occurs. When the electric current is started to the heater wire 61b, a hot wire is radiated from the heater wire 61b via the glass tube 61a to the cooler 60 and peripheral components. At this time, a part of the hot wire radiated to the protective plate 66 is reflected by the heater wire 61b through the glass tube 61a from the shape of the protective plate 66. In addition, some of the defrost water melted by the heat from the defrost heater falls directly into the gutter 67, and otherwise falls to the roof 65. In addition, since this roof 65 is low temperature compared with the glass tube 61a, steam explosion does not reach here.

Generally, not only the heater wire 61b surface of the defrost heater 61 but the surface temperature of the glass tube 61a becomes very high temperature. This is because the protection plate 66 is in the vicinity of the defrost heater 61, and the heating wire once radiated through the glass tube returns to the protection plate 66 to abnormally heat the glass wire 61a as well as the heater wire 61b. As a result, there was a possibility that the rubber stopper for sealing both ends of the defrost heater 61 could be damaged by heat.

In addition, when the coil end portion (straight portion braided by returning the heater wire 61b which is not a coil shape to a predetermined length) made to the heater wire end in order to protect the rubber stopper is long, a glass tube or the like may be made constant. When the frost attached to the cooler 60 in the upper portion of the coil end is delayed, there is a problem that the defrost time is long.

In addition, in the defrost heater 61 having a shape as shown in the figure, since the heat wire is 1/4 to 1/5 smaller than the internal length dimension D1 of the cooler 60, the hot wire is the total internal length of the cooler 60. There was a problem that it did not evenly reach D1 (as shown in Fig. 13), and delayed the defrost time.

Moreover, as described in patent document 2, when the heater wire was set as the structure which covers an insulation material, there existed the following problems. When the heater wire is energized, not only the sheath tube but also the insulating material itself covering the heater wire is heated to generate heat. In the above-mentioned Patent Document 2, since both ends of the sheath tube are sealed with a cap, heat is transferred to the cap through the insulating material when the periphery of the heater wire is covered with the insulating material. At this time, even if a high heat resistance property such as silicone rubber is used for the cap, the heat resistance temperature is about 145 ° C. If the temperature is higher than the heat resistance temperature, the cap is damaged. In that case, it is necessary to separately install a heat insulation member between an insulating material and a cap.

In addition, if the heat generation temperature of the heater wire is set low, the output as the defrost heater is lowered and the performance as the defrost heater is lowered. On the other hand, if the insulating material itself is excellent in heat insulating properties, the temperature of the heater wire cannot be transmitted to the outside, and this case also leads to deterioration of the performance as the defrost heater. Therefore, in order to secure the output as a frost elimination heater, a heater wire must be lengthened and this leads to the reduction of the effective volume in a refrigerator.

In addition, since the defrost heater itself is disposed near the cooler, the ambient temperature becomes -30 ° C or lower during normal operation of the refrigerator. In defrosting operations, heater wires are hundreds of degrees when energized, but this does not take into account the expansion and contraction of the insulation against their temperature changes. In addition, the temperature of the heater wire itself covered with the insulating material was not considered.

The present invention has been made in view of the above-described problems by using a flammable refrigerant, and an object thereof is to provide a refrigerator aimed at improving safety and efficiency.

In order to achieve the above object, the present invention is a refrigerator provided with a defrosting heater having a heater wire wound in a coil shape in a glass tube below the cooler, wherein a heat dissipation member is provided on the outer circumference of the glass tube.

In addition, the heater wire has a coil portion wound in a coil shape and a straight portion disposed on both sides of the coil portion, and both sides of the glass tube have a sealing member for sealing the glass tube, and the heat dissipation member faces the coil portion. It shall be provided in the outer periphery of the glass tube.

In addition, in the refrigerator provided with the cooler connected to the refrigerating cycle which enclosed the combustible refrigerant | coolant in the heat insulation box member, and the frost removal heater is arrange | positioned under the said cooler, in the present invention, the frost removal heater is wound in a coil shape in a glass tube. A heater wire having a coiled portion and a straight portion positioned on both sides of the coil portion, and a hole portion for communicating both inside and outside of the glass tube so as to seal both ends of the glass tube and pass the lead wire connected to the heater wire or the heater wire. The sealing member and the heat radiating member arrange | positioned at the outer peripheral part of the glass tube which oppose the said coil part were provided.

Further, in the above, a roof member is provided between the cooler and the glass tube, and the heat dissipation member is a thin heat dissipation fin wound around the glass tube, and the heat dissipation fin width is larger than the width of the roof member and is inside the cooler. It was smaller than the width, and the outer part of the downward projection surface of the said roof member of the said heat radiating fin was taken as the shape extended in the perpendicular direction. Similarly, in the above, the roof member was provided between the cooler and the glass tube, and the defrost heater having the heat dissipation fin as an auxiliary member for continuously contacting the heat dissipation member with the roof member was provided.

Further, the winding pitch of the coil part is set to 2.0 mm or less, the pitch of the heat dissipation member is made larger than the winding pitch of the coil part, and the distance between the coil part and the glass tube is 1 mm or less, so that the heat generation temperature of the heater wire is increased. It was set to 400 degrees C or less, and to suppress below the ignition point temperature of a flammable refrigerant.

Further, a defrost heater having a heater wire wound in a coil shape inside the glass tube and sealed at both ends with a rubber stopper is installed under the cooler, and the defrost heater is configured in a refrigerator using a hydrocarbon-based isobutane as a refrigerant. The surface temperature of the glass tube and the heater wire temperature were controlled to be below the set temperature using the heat radiating member.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

1 is a longitudinal cross-sectional view of a refrigerator provided with the present invention, FIG. 2 is an enlarged view of an essential part of FIG. 1, FIG. 3 is an explanatory view of a cross-sectional view of the defrost heater of FIG. 2, and FIG. 5 is a cross-sectional explanatory diagram of a defrost heater for explaining an embodiment different from FIG. 3, FIG. 6 is an explanatory view of the heat dissipation fin in FIG. 5, and FIG. 7 is an inclination diagram of the heat dissipation fin explaining the embodiment different from FIG. 5. 8 is a perspective view of the arrow P in FIG. 7, FIG. 9 is a cross-sectional explanatory diagram of a defrost heater equipped with the present invention, and FIG. 10 is an explanatory diagram of a refrigeration cycle provided with the present invention.

<First Embodiment>

First, the first embodiment will be described with reference to FIGS. 1 to 4. The refrigerator main body 1 has the freezing compartment 2 and the refrigerating compartment 3 inside. The front face of the freezer compartment 2 is provided with a freezer compartment door 4 that closes the opening, and the front face of the freezer compartment 3 is provided with a refrigerator compartment door 5 that closes the opening. An intermediate partition wall 6 is provided between the freezer compartment 2 and the refrigerating compartment 3 to divide the two chambers, and the intermediate compartment wall 6 is a cooler which will be described later with cold air heat exchanged with food in the freezer compartment 2. The channel | path 7 which returns to the furnace and the channel | channel 8 which returns cold air heat-exchanged with the food in the refrigerator compartment 3 to a cooler is formed.

The cooler chamber 9 partitioned by the partition partition 13 is arrange | positioned at the rear part of the freezer compartment 2, In this cooler chamber 9, the cooler 10, the defrost heater 11, and the cold air circulation fan ( 12) is installed. In the present embodiment, the defrost heater 11 is disposed below the cooler 11, and the return cold air introduced from below in the cooler chamber 9 by the cold air circulation fan 14 disposed above the cooler is upward. Is sent to. The cold air sent upward is cooled by the cooler 10, and is taken out to the freezing chamber 2 from the cold air outlet 14 provided in the partition partition 13.

An aluminum roof 15 is provided between the defrost heater 11 and the cooler 10. The roof 15 prevents the defrost water dropped from the cooler 10 directly splashing on the defrost heater 11 when the frost attached to the cooler 10 is melted by the heat of the defrost heater 11. . In general, the glass tube 11a of the defrost heater 11 has a surface temperature of around 500 ° C. when the defrost heater 11 generates heat. Dropping water directly onto the glass tube 11a causes a vapor explosion state and becomes loud enough to be heard outside of the refrigerator, giving anxiety to the user. Preventing this is the role of the roof 15.

The heat radiating member is arrange | positioned at the outer periphery of the glass tube 11a of the defrost heater 11. In this embodiment, a fin-shaped heat dissipation fin is wound around the outer circumference of the glass tube 11a. This heat dissipation fin 16 is wound around a strip of thin strip in a coil shape as shown in FIG. This strip-shaped thin plate is wound up continuously in a coil shape on a core having an outer diameter substantially the same as that of the glass tube 11a, or slightly larger than that, and cut into a predetermined dimension. In addition, when winding a strip | belt-shaped thin plate in coil shape, it performs by putting a slit in the outer peripheral side, or throttling an inside. In this embodiment, the one end of the strip-shaped thin plate is throttled to form a coil so that the center hole 16a side becomes corrugated. Compared with the case where a slit is placed on the outer circumferential side, the heat dissipation area of the heat dissipation fin 16 as a whole is increased, and the contact area with the glass tube 11a is also increased, thereby enabling more efficient heat dissipation.

Since the diameter of the glass tube 11a in the present Example is 10.5 mm, the diameter of the core which winds a strip-shaped thin plate is made into about 11.0-11.5 mm. As a result, when attaching the heat dissipation fin 16 wound in the coil shape to the glass tube 11a, the center hole 16a formed by 11.0-11.5 mm may be inserted through the 10.5 mm glass tube 11a.

Thus, the heat dissipation fin 16 replaces the conventional protection plate. That is, even if the glass tube 11a may be broken by any impact, even if the heat radiation fin 16 which is in the form wound up over the longitudinal direction of the glass tube 11a breaks | disconnects the heater wire 11b, Since holding is carried out, the heater wire 11b is not suspended even if the glass tube 11a is broken like conventionally.

In this embodiment, the heat dissipation fins 16 are made of aluminum. By using a member having a higher thermal conductivity than the glass tube 11a, the heat of the heater wire 11b can be radiated to the outside efficiently. In addition, in this embodiment which employs the structure which winds up the heat radiation fin 16 around the glass tube 11a, when the weight of the heat radiation fin 16 becomes large, it will become the weight load with respect to the glass tube 11a, This leads to breakage. Therefore, among the members with good thermal conductivity, for example, aluminum is used which is lighter, has better moldability, and is superior in cost than copper.

In other words, the heat dissipation fin is a strip-shaped thin plate which is continuously wound on a core having the same diameter as the glass tube, and cut into a predetermined dimension to form a heat dissipation fin. Since it can be easily carried out by inserting the above, it is of course very advantageous in terms of cost.

Next, in FIG. 3, the defrost heater 11 will be described. This defrost heater 11 arrange | positions the heater wire 11b in the glass tube 11a of an outer diameter of 10.5 mm and an inner diameter of 8.5 mm, and is provided with the sealing member 17 which covers the both ends of this glass tube. The member shown by the code | symbol 18 is a positioning member, and the operation | movement of this positioning member 18 is mentioned later.

The both ends of the heater wire 11b are connected to the lead wire 19, and the connection member 21 which connects the linear part 11c of the heater wire 11b and the lead wire 19 is arrange | positioned at the connection part. This defrosting heater 11 is a partition plate as shown in the drawing which shows the heater wire 11b which wound the nichrome wire of 0.5 mm of wire diameter into the coil shape of outer diameter 7.0 mm in the glass tube of diameter 10.5mm and thickness 1mm. 18) and the both ends of the glass tube 11a were sealed with the sealing member 17. As shown in FIG. In this example, a rubber stopper is used as the sealing member 17.

Moreover, the both sides of the coil part of the heater wire 11b wound by the coil shape have the straight part 11c formed in linear form as shown in FIG. This is to prevent the rubber stopper 17 from being damaged by the heat generated by the heater wire 11b. The rubber stopper 17 is made of a material having high heat resistance characteristics such as silicone rubber, but the heat resistance temperature of the rubber stopper 17 is also usually 145 ° C or lower. By the way, the temperature of the coil part of the heater wire 11b is 500 degreeC, and it becomes temperature much higher than the heat resistance temperature of the rubber stopper 17. FIG. This is because the inside of the glass tube 11a is provided with the heater wire 11b which generate | occur | produces heat, or temperature rises upward by reflection of the heat from upper roof, lower protection board, etc. When this heat is transmitted to the rubber stopper 17 at the temperature of the state, the rubber stopper 17 is damaged by high heat.

However, since the linear part 11c originally has a small amount of heat generation, it does not become 500 degreeC. Therefore, in this example, the straight part 11c is provided in the both sides of the coil part of the heater wire 11b. By this structure, the heat of the heater wire 11b and the glass tube 11a can be prevented from being transmitted to the rubber stopper 17.

The longer the distance of the straight portion 11c is, the more effective it is to prevent heat conduction to the rubber stopper 17. However, if the distance is too long, the capacity of the defrost heater is reduced. The distance (for example, 15 mm-20 mm) which considered the heat generation temperature of the heater wire 11b is taken. In other words, if the straight portion 11c is lengthened, it is possible to prevent damage to the rubber stopper 17 due to heat.However, among the limited dimensions, the length of the straight portion 11c is longer than the watt density (heating amount per unit length). ) Is gradually increased to act in a direction of increasing the temperature of the coil portion of the heater wire 11b. Therefore, it is usually set to 15 mm to 20 mm. In this example, the positioning member provided between the rubber stopper 17 and the glass tube 11c so that the coil part may be located in the center part of the glass tube 11a so that the length of the linear part 11c of both sides may be about the same. The position of the coil part is determined by (18). In this state, the heater wire 11b generates heat to prevent excessive transfer of heat to the rubber stopper 17, and efficiently radiates heat generated from the coil portion to the outside by the heat dissipation fins 16, thereby providing reliability. Is raising.

That is, as described above, since the heat dissipation fin 16 has a higher thermal conductivity than the glass tube 11a, and the heat dissipation fin 16 is disposed at the portion having the coil portion inside the glass tube 11a, the heat dissipation fin 16 can rise even around 500 ° C. It has the effect | action which lowers the temperature in the glass tube 11a to 350 degreeC vicinity, for example. If the length of the heat dissipation fin 16 in the outer circumferential direction is sufficient, heat dissipation is good, and even if the fan pitch is larger than the coil portion, the heat dissipation effect is sufficiently exhibited. As described above, the heat dissipation fin 16 is heat-exchanged with the glass tube 11a to use the heat dissipation fin 16 having a good heat dissipation area and thermal conductivity that can lower the surface temperature of the glass tube 11a from 350 deg. C to 300 deg. The temperature of the heater wire 11b itself is also lowered to around 350 ° C.

On the other hand, the heat radiation fins 16 heat exchanged with the glass tube 11a radiate heat to the entire inner dimension D2 of the cooler 10 as shown in FIG. In other words, the size of the heat dissipation fin 16 is larger than the roof 15 dimension L1, and it is better to bring the inner dimension D2 of the cooler 10 as close as possible. Therefore, although the frost removal water from the cooler 10 may be dripped at the position part of the outer side from the downward projection surface of the roof 15 of this heat radiation fin 16, the corresponding part of the heat radiation fin 16 extends substantially vertically. Since it is made into the shape made into a shape, it does not store the dripped defrost water.

The heat dissipation fin 16 of this size is suitable for melting the frost attached to the trough 20 or the passages 7 and 8 that receive frost removal water at the time of frost removal, as well as defrosting the cooler 10. It can be shortened.

In a refrigerator having such a configuration, when the amount of frost deposited on the cooler 10 increases, heat transfer to air that exchanges heat with the surface of the cooler 10 is inhibited, and the ventilation resistance is lowered. The refrigerator having detected this starts energizing the defrost heater 10.

When the electric current is started to the heater wire 11b, a heat wire is radiated from the heater wire 11b via the glass tube 11a and the heat radiation fin 16 to the cooler 10 and peripheral components. Thereby, the frost attached to the cooler 10, the trough 20, or the like is melted with frost removal water.

At this time, the defrost heater of the present invention having the heat dissipation fins 16 uses the thin glass tube 11a as a heat dissipation fin larger than the roof L1, and thus heats the cooler 10 lower end to a wide range. As a result, the defrost time can be shortened.

In addition, even when there is an accident that the glass tube 11a is broken, the heat dissipation fins 16 are attached to the outer circumference of the glass tube 11a. Thus, the glass tube 11a collapses and the heater wire 11b is out of the glass tube 11a. It is not said to hang and damage surrounding parts.

Alternatively, when the glass tube 11a is ruptured, problems such as leakage of electricity into the metal part of the refrigerator main body 1 as in the prior art are eliminated.

Second Embodiment

Next, an embodiment different from the first embodiment will be described with reference to FIGS. 5 and 6. The defrost heater 11 is provided with the glass tube 11a, the heater wire 11b, and the rubber stopper 17. As shown in FIG. The heater wire 11b has the straight part 11c on both sides. The straight portion 11c is connected to the lead wire 19 by the connecting member 21 located in the rubber stopper 17. The heat dissipation member 22 is wound around the outer circumference of the glass tube 11a. This heat radiation fin 22 winds a rod-shaped (wire-shaped) member in coil form. This heat dissipation fin 22 cannot take a heat dissipation area as compared with the heat dissipation fin 16 described in the first embodiment, so that the winding pitch is narrowed. The heat dissipation fin 22 cannot increase the output of the heater wire 11b as the heat dissipation source as in the first embodiment, but the glass tube 11a is combined by lowering the total amount of heat generated by, for example, 160 W to 140 W or the like. And the heater wire 11b temperature can be lowered to a desired temperature. That is, heat of the heated glass tube 11a is transferred to the heat radiation fins 22 and promotes frost removal via the heat radiation fins 22. Thereby, the temperature of the glass tube 11a and the heater wire 11b is drastically reduced. Moreover, even when there is an accident that the glass tube 11a is broken, since the glass tube 11a prevents collapse by the heat radiation fin 22, it can be said that there is no suspension of the heater wire 11b.

Third Embodiment

7 and 8, an embodiment different from the first and second embodiments will be described.

In the figure, the heat dissipation member 23 of the present embodiment is a door-shaped roof with a heat dissipation member (heat dissipation fin). The horizontal member of the roof 23, i.e., the ceiling surface 23a, is loaded with defrost water from the cooler. The roof 23 has vertical members 23b on both sides that are auxiliary members. The vertical members 23b on both sides form heat radiating fins 24 that radiate heat from the defrost heater 11 (FIG. 2).

That is, a hole 25 through which the defrost heater 11 can be inserted in advance is opened in the vertical member 23b which is the auxiliary member on both sides, and this is bent inward alternately as shown in Figs. The holes 25 are matched, and the defrost heater 11 is inserted therethrough.

In this manner, since the roof 23 and the heat dissipation fins 24 are integrated together, the roof 23 can be utilized as the heat dissipation fins 24, and the window 26 generated after bending the heat dissipation fins 24 is formed. Since it may be an outlet of the heated air, the heated air is fed into the cooler side without the heated air staying in the door-shaped roof 23.

At this time, the hole diameter of the hole 25 is about 11.0 to 11.5 mm when the defrost heater 11 is 10.5 mm in diameter, and the glass tube 11a of the defrost heater 11 is moved to the hole 25. It is configured to go in smoothly.

In this embodiment, the cutting slits were inserted in both sides of the vertical member 23b, which is an auxiliary member of the door-shaped roof 23, and bent inward from the slit to form a heat dissipation fin. In view of this, this is selectable, and this embodiment proposes to utilize the roof 23 as part of the heat dissipation fin 24.

By the above configuration, the heat dissipation area of the glass tube 11a is enlarged by the heat dissipation fins 24. As a result, the temperature of the glass tube 11a is greatly reduced. In other words, the heater wire 11b temperature is also lowered, and the rubber stopper 17 (FIG. 3) is not damaged by heat.

In addition, even if the glass tube 11a may be broken, since the glass tube 11a is supported by the heat radiation fin 24, it is said that the glass tube collapses and the heater wire 11b inside is suspended to the trough 20 (FIG. 2) side. There is nothing to do.

Fourth Example

9 and 10, an example in which a defrost heater is used in a refrigerator using a hydrocarbon-based isobutane as a refrigerant will be described.

10 shows a refrigeration cycle, in which a compressor 26, a condenser 27, a capillary tube 28, and a cooler 29 are connected in series and in an annular fashion to constitute a refrigeration cycle. Conventionally, freon refrigerants have been used for refrigerants enclosed in the refrigeration cycle because of their stable physical properties and easy handling. This freon refrigerant has been developed in a hydrocarbon refrigerant, such as propane (R-290a) or isobutane (R600a), which has little effect on ozone layer destruction and global warming. Hereinafter, this hydrocarbon type refrigerant | coolant is called HC refrigerant.

Thus, the HC refrigerant is sealed in the refrigerating cycle of this embodiment. This HC refrigerant leaks into the refrigerator during the defrost operation when there is damage in the welded portion of the cooler 29 or the like.

If the HC refrigerant is full in the refrigerator, there is a risk that the HC refrigerant is ignited upon heating of the defrost heater.

That is, during the defrost operation, the cooler is heated from the defrost heater, so that the isobutane in the cooler 29 becomes higher than atmospheric pressure (about 3 Kg / cm 2) and leaks into the refrigerator. In addition, in the cooling operation, isobutane in the cooler becomes negative with respect to atmospheric pressure, and isobutane does not leak into the refrigerator. In addition, since isobutane of a cooler is almost equal to atmospheric pressure even if a compressor stops normally, it rarely leaks into a refrigerator.

As shown in FIG. 10, the cold air circulation fan 30 and the defrost heater 31 are arrange | positioned in the vicinity of the cooler 29. As shown in FIG. Usually, the cooler 29 and the defrost heater 31 are provided in the cooler chamber, and the cold air cooled in the cooler 29 is sent to the refrigerating chamber and the freezing chamber by the operation of the cold air circulation fan 30 disposed above the cooler. To cool the food. Similarly, the cold air circulation fan 30 sends the return cool air from the refrigerating chamber or the freezing chamber to the cooler chamber from below the cooler, and the return cool air is further cooled by the cooler 29 to send the cool air to the freezing chamber or the freezer compartment. . In this way, the cold air circulation fan 30 circulates the cold air forcibly.

In addition, the defrost heater 31 is for melting the frost when the frost is deposited on the cooler 29, the specific configuration is as shown in FIG. The defrost heater 31 covers the heater wire 31b by the glass tube 31a, and this heater wire 31b consists of the coil part a and the straight part b, and the coil part a is a glass tube When the inner diameter of 31a is 8.5 mm, it is wound up and comprised by the coil shape of the outer diameter 7.5 mm. In this case, the distance between the outer circumference of the coil part and the inner circumference of the glass tube 31a is about 0.5 mm, that is, the heater wire 31b is provided in the glass tube 31a in close proximity to the inner surface of the glass tube. In addition, the winding pitch of the coil part a is wound up to 2.0 mm or less. Thus, when the winding pitch is set to 2.0 mm or less, it is influenced by adjacent heater wires, and it has a possibility of temperature rising above the heat generation amount of the coil part a itself of the heater wire 31b. Or since the distance between the coil part a and the inner periphery of the glass tube 31a is 1 mm or less, the heat which rose in temperature more than this heat amount is easy to be transmitted to the glass tube 31a.

In the defrost heater 31 having the above configuration, the temperature of the glass tube 31a facing the coil portion a rises to the vicinity of the heater wire 31b. In this embodiment, since the coil part a is wound by 7.5 mm of outer diameters, and the inner diameter of the glass tube 31a is 8.5 mm, the temperature of the part of the glass tube 31a which opposes the coil part a is a heater wire. 31b, as the temperature approaches, the rubber stopper 32 at both ends is damaged by this heat.

The straight part b of the heater wire 31b points to the part which made the heater wire 31b linear in order to prevent the damage of the rubber stopper 32 of both ends. Since the calorific value of this part is naturally small, the temperature of the part of the glass tube 31a which opposes this linear part b does not reach to the glass tube 31a temperature corresponded to the coil part a. However, when the dimension of this straight part b is short, the air temperature in the glass tube and the glass tube 31a are naturally heated under the influence of the heat of the coil part a. For this reason, it is usually necessary to secure the L2 dimension by 15 mm or more.

The rubber stopper 32 seals both ends of the glass tube 31a and is made of a silicone rubber having heat resistance (for example, 145 ° C). The positioning member 33 of the heater wire constitutes an end of the glass tube 31a and is provided at the end of the glass tube 31a. By this positioning member 33, the coil part a of the heater wire 31b is positioned. That is, the positioning member 33 is provided so that the coil part a may be arrange | positioned in the longitudinal center part of the glass tube 31a.

The position of the connection member 34 which connects the linear part b and the lead wire 35 is positioned by the previous positioning member 33. Thereby, L2 dimension of the rubber stopper 32 and the linear part b can be set to predetermined dimension with positioning of the coil part a.

In the refrigerator provided with the defrost heater 31 having such a configuration, when frost is accumulated in the cooler 29 and defrost is required, energization to the defrost heater 31 is started. When the energization to this defrost heater is started, if the cooler 29 has a broken part, HC refrigerant will leak from the broken part. Since the ignition temperature of this HC refrigerant, for example, isobutane, is 494 ° C, it is necessary to lower the temperature of the heater wire 31b than this ignition temperature. In the present embodiment, in consideration of safety, the temperature is set to 400 ° C or lower, that is, 394 ° C.

In other words, in this embodiment, the heat dissipation fins 36 are provided on the defrost heater 31 (glass tube 31a, heater wire 31b) to be 394 ° C or lower. The heat dissipation fins 36 may be arbitrarily selected in the shapes and forms shown in the first, second and third embodiments and the like. What is needed is a heat dissipation member (heat dissipation fin) which can lower the temperature of the defrost heater 31, for example, a heat dissipation member which is a member whose heat conductivity is higher than glass tube 31a. Therefore, since the coil-shaped heat dissipation fin which has better thermal conductivity than the glass tube 31a is arrange | positioned in the glass tube 31a which opposes the coil part a, the coil part of the heater wire 31b provided near the glass tube 31a ( The heat of a) is radiated to the outside efficiently. For this reason, even if the winding pitch of the coil part a is 2.0 mm or less, it does not reach the ignition point temperature of HC refrigerant | coolant. In addition, since the amount of heat delivered to the rubber stopper 32 at both ends by transferring the glass tube 31a from the heat generation amount of the coil part a is obtained by subtracting the amount of heat radiated from the heat dissipation fin, the rubber stopper 32 is prevented from being damaged. can do.

In addition, in this embodiment, it is set as the single glass tube instead of the double glass tube heater used in consideration of explosion-proof property with respect to a flammable refrigerant. In the single glass tube as described above, the temperature of the glass tube 31a can be reduced by the heat dissipation fin 36, and the air temperature in the glass tube 31a can also be lowered by this action, so that the heater wire provided in the glass tube The rise of the temperature of 31b can be suppressed and even the temperature of the heater wire 31b can be 394 degrees C or less.

That is, in the case of using a double glass tube, the air between the inner glass tube and the outer glass tube acts as a heat insulating material. For example, even if a heat dissipation fin is attached, the heater wire temperature cannot be immediately lowered to 394 ° C or less. The method of changing the pitch of a line is needed. This embodiment has a different structure from the double glass tube in which the heat insulation air layer between the inner and outer glass tubes is left in such a way that the thermal efficiency remains, and the heat of the heater wire 31b is lost to the heat dissipation fin via the glass tube. And the temperature of a heater wire can be 394 degrees C or less. In addition, the winding pitch of the heater wire 31b can be set to 2.0 mm or less in this way, and since the heat of the heater wire 31b is efficiently transmitted to the surroundings by the heat radiation fins 36, defrosting of the cooler 29 is eliminated. Can be performed with a small power consumption.

Since each Example of this invention has a structure as demonstrated above, it has the following effects.

That is, in a refrigerator in which a heater wire wound in a coil shape is incorporated in a glass tube and a defrost heater having both ends sealed with a rubber stopper is installed in the lower part of the cooler, the heat dissipation is attached so that the inner circumference is in contact with or near the outer circumference of the glass tube. Since the member (heat radiating fin) is provided between the rubber stoppers, it is possible to eliminate the collapse of the glass tube at the time of the glass tube rupture and to prevent the suspension of the heater wire without the heating wire from the heater wire being returned to the defrost heater again.

At the same time, in the present invention, not only the glass tube temperature but also the temperature of the heater wire can be lowered. Thereby, the refrigerator which can eliminate the damage etc. of a rubber stopper can be obtained.

In addition, since the heat dissipation member is a strip-shaped thin plate or rod-shaped heat dissipation member, it is continuously wound on a core having the same diameter as that of the glass tube, and cut into a predetermined dimension to form a heat dissipation member (heat dissipation fin). Since the glass tube can be inserted through the hole made from the core, it can be easily performed, and the cost is very advantageous.

In addition, since the heat dissipation member is a heat dissipation fin made of an auxiliary member which is in continuous contact with the roof provided on the defrost heater, the heat dissipation fin attached to the glass tube can be reduced because the roof can be utilized as the heat dissipation fin.

In addition, since the outer shape of the heat dissipation member attached to the glass tube is larger than the roof dimension Ll provided on the frost removing heater, the entire inner dimension of the cooler can be heated unlike the conventional art, and thus the defrost time can be shortened. will be.

A glass tube constituting a defrost heater in a refrigerator using a hydrocarbon-based isobutane as a refrigerant by installing a defrost heater in which a heater wire wound in a coil shape is wound in a glass tube and sealed at both ends with a rubber stopper under the cooler. Since the surface temperature and the heater wire temperature are controlled to be below the set temperature using a heat radiating member (heat radiating fin), the HC refrigerant may be a source of ignition even if HC coolant leaks from a damaged part of the cooler. It is not there.

In addition, since the heat dissipation member (heat radiating fin) was made into the defrost heater which wound the glass tube in order to make the temperature at the time of exothermic of the defrost heater to 394 degreeC which is -100 degreeC of ignition point temperature of hydrocarbon type isobutane, it is a refrigerator. In the use state, since the heat dissipation member (heat dissipation fin) can make the safety factor of 394 degrees C or less seen with both the glass tube and heater wire temperature which comprise a defrost heater, a defrost heater does not become a ignition source of HC refrigerant.

According to the present invention, even when the defrosting operation of the refrigerator using the combustible refrigerant can be improved, safety and efficiency can be improved, and a refrigerator having excellent reliability can be provided.

Claims (7)

In the refrigerator provided with the defrosting heater which has the heater wire wound by the coil shape in the glass tube below the cooler, A refrigerator provided with a heat dissipation member on an outer circumference of the glass tube. The said heater wire has a coil part wound by the coil shape, and the linear part arrange | positioned at both sides of this coil part, The both sides of the said glass tube have the sealing member which seals the said glass tube, The heat dissipation member is provided in the outer circumference of the glass tube facing the coil portion. In the refrigerator provided with the cooler connected to the refrigeration cycle which sealed the flammable refrigerant | coolant in a heat insulation box member, and the frost removal heater is arrange | positioned under the said cooler, The defrost heater includes a heater wire having a coil portion wound in a coil shape in a glass tube and a straight portion positioned on both sides of the coil portion, and sealing both ends of the glass tube to pass the lead wire connected to the heater wire or the heater wire. And a sealing member having a hole portion communicating with the inside and the outside of the glass tube, and a heat dissipation member disposed on an outer circumferential portion of the glass tube facing the coil portion. 4. The roof member according to any one of claims 1 to 3, wherein a roof member is provided between the cooler and the glass tube, and the heat dissipation member is a thin heat dissipation fin wound around the glass tube, and the heat dissipation fin width is the roof member. A refrigerator, characterized in that it is larger than the width of the cooler and smaller than the width of the inner length of the cooler, and the outer portion of the downward projection surface of the roof member of the heat dissipation fin is elongated in the vertical direction. The defrost heater according to any one of claims 1 to 3, further comprising a roof member provided between the cooler and the glass tube, and an auxiliary member for continuously contacting the heat dissipation member with the roof member as a heat dissipation fin. One refrigerator. The winding pitch of the said coil part is made 2.0 mm or less, making the pitch of the said heat radiating member larger than the winding pitch of the said coil part, and making the distance of the said coil part and the said glass tube 1 mm or less, And a heat generating temperature of the heater wire is 400 ° C. or lower and suppressed below a ignition point temperature of the flammable refrigerant. In a refrigerator using a isobutane of hydrocarbon type as a refrigerant, a defrost heater having a heater wire wound in a coil shape in a glass tube and sealed at both ends with a rubber stopper is installed under the cooler. The refrigerator which suppressed the surface temperature and heater wire temperature of the glass tube which comprise the said defrost heater below below a preset temperature using a heat radiating member.

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