JP2003007436A - Glass tube heater and cooling stocker provided with this glass tube heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance safety of a glass tube heater to defrost a cooler of refrigeration cycle in which an inflammable refrigerant is used. SOLUTION: In the vicinity of a cooler 61 of the refrigeration cycle in which the inflammable refrigerant is applied, the glass tube heater 66 in which the heater 70 is coated by the glass tube 71 is arranged, and the strength of the glass tube 71 is made to be 2 to 4 fold of that in case the tube is applied to the refrigeration cycle in which flon series refrigerant is applied, thereby catching fire to the refrigerant due to an exposure of the heater, which was not a problem in case of the flon series refrigerant by the nonflammable characteristic can be prevented, and the safety can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass tube heater used for defrosting a cooling storage using a flammable refrigerant.

[0002]

2. Description of the Related Art In recent years, a glass tube heater is generally used for defrosting a cooler of a cooling storage. Among them, Japanese Patent Application Laid-Open No. 8-
An example is shown in Japanese Patent No. 54172.

The conventional refrigerator will be described below with reference to the drawings.

FIG. 7 is a vertical cross-sectional view of a main part of a conventional refrigerator, and FIG. 8 is a perspective view of a defrost heater of the refrigerator.
In FIGS. 7 and 8, 1 is a refrigerator body, 2 is a freezer compartment inside the refrigerator body 1, 3 is a refrigerating compartment inside the refrigerator body 1, 4 is a freezer compartment door, 5 is a refrigerating compartment door, and 6 is A partition wall that separates the freezer compartment 2 and the refrigerating compartment 3, 7 is a freezing inlet for sucking air in the freezer compartment 2, 8 is a refrigerating compartment inlet for sucking air in the refrigerating compartment 3, and 9 and 10 are outlets for discharging cold air. Outlet, 11 is a cooler, 12 is a fan for circulating cold air, 13 is an evaporator 11
And a cooler partition wall for partitioning the freezer compartment 2, 14 a trough, 15 a drainage port, 16 a glass tube heater as a defrosting means, a heater 20 having a coil of iron chrome wire, a glass tube 21 and a cap 22. , And a lead wire 23 connected to the heater 20 on both end surfaces of the cap 22.

The glass tube 21 generally has an outer diameter of 10.
5 mm and a plate thickness of 1.0 to 1.1 mm are used. As the material, high-purity quartz glass or opaque quartz glass having a high heat resistant temperature is used.

The strength of the glass tube is generally measured by a measuring method shown in FIG. 9 when a load of 50 to 100 N is applied.
It has a strength that does not cause damage or cracks.

Reference numeral 17 denotes a roof for preventing evaporation noise generated when the defrost water directly drops on and contacts the defrost means 16. Further, 18 is a compressor, and 19 is an evaporation dish provided on the upper part of the compressor.

Next, the operation will be described. When cooling the freezer compartment 2 or the refrigerating compartment 3, the refrigerant flows through the cooler 11 to cool the cooler 11. Fan 12
The heating air of the freezing compartment 2 or the refrigerating compartment 3 is sent from the freezing compartment suction opening 7 or the refrigerating compartment suction opening 8 to the cooler 11, where it is heat-exchanged and cooled, and the cooling air is discharged from the discharge openings 9 and 10. Is sent to the freezer compartment 2 or the refrigerator compartment 3 for cooling. Here, the air that exchanges heat with the cooler 11 is the freezer compartment door 4 and the refrigeration compartment door 5.
Inflow of high-temperature outside air by opening and closing, and freezer compartment 2 and refrigerator compartment 3
Since the air is highly humidified by the evaporation of the moisture of the stored food, the moisture in the air becomes frost and frost forms on the cooler 11 which has a lower temperature than the air. In this way, the cooler 1
When 1 is frosted, heat transfer between the surface of the cooler 11 and the air for heat exchange is hindered as the amount of frost increases, and the air flow resistance becomes low, so that the heat flow rate decreases and the cooling is insufficient. Occurs.

From this, the nichrome wire of the defrosting means 16 is periodically energized. The radiant heat emitted thereby melts the frost on the cooler 11, the trough 14, and the drainage port 15 into water. Further, a part of the defrosted water thus melted falls directly into the tub 14, and the other part falls into the tub 14 while avoiding the defrosting means 16 by the roof 17 and is discharged from the drainage port 15 to the outside of the refrigerator.

[0010]

However, in the above-mentioned conventional configuration, the external force is applied to the defrosting means 16 and the glass tube 2
1 may be damaged and the heater 20 may be exposed.
When a flammable refrigerant is used in the refrigeration cycle, the flammable refrigerant leaks into the refrigerator, and when the heater 20 is energized, the flammable refrigerant is ignited and there is a risk of becoming unsafe.

The present invention solves the conventional problems, and an object of the present invention is to provide a refrigerator using a flammable refrigerant to improve the safety.

[0012]

The invention according to claim 1 of the present invention is a glass tube heater which is arranged in the vicinity of a cooler of a refrigeration cycle to which a flammable refrigerant is applied and whose heater wire is covered with a glass tube. In the above, the strength of the glass tube is set to be 2 to 4 times the strength of the glass tube when used in a refrigeration cycle to which a fluorocarbon refrigerant is applied, and there is no problem with the fluorocarbon refrigerant due to the property of noncombustibility. Ignition of the refrigerant due to exposure of the heater can be prevented by increasing the strength of the glass tube while maintaining the defrosting performance of the glass tube heater.

According to a second aspect of the present invention, there is provided a glass tube heater which is disposed in the vicinity of a cooler of a refrigerating cycle to which a flammable refrigerant is applied, and a heater wire is covered with a glass tube. The thickness is 1.2 to 2.0 mm, and the strength can be efficiently improved without lowering the radiation transmittance.

According to a third aspect of the present invention, there is provided a glass tube heater which is disposed in the vicinity of a cooler of a refrigerating cycle to which a flammable refrigerant is applied and which coats a heater wire with a glass tube. 15 to 30 mm,
It is possible to secure the installation space and increase the strength while lowering the surface temperature of the glass tube.

According to a fourth aspect of the invention, in the invention of the first or third aspect, the glass tube has a multiple structure, and the surface temperature of the glass tube is further lowered, and then the installation space is set. Can be secured and the strength can be increased.

A fifth aspect of the present invention is a cooling storage provided with the cooling device according to any one of the first to fourth aspects, in which a flammable refrigerant leaks due to breakage of the glass tube heater. It is possible to prevent ignition and improve the safety of the cooling storage.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a cooling storage device equipped with a glass tube heater and a cooling device according to the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view of a main part of a glass tube heater according to Embodiment 1 of the present invention, and FIG. 2 is a glass tube perspective view of the glass tube heater of the same embodiment. FIG. 3 is a characteristic diagram showing strength and cost performance (safety factor / cost) of the glass tube heater of the same embodiment. FIG. 4 is a characteristic diagram showing the plate thickness and strength of the glass tube heater of the same embodiment. FIG. 5 is a vertical cross-sectional view of a main part of a cooling storage in which the glass tube heater of the same embodiment is used as a defrosting means and a refrigerating cycle is filled with a combustible refrigerant.

1 to 5, reference numeral 51 is a refrigerator main body as a cooling storage, 52 is a freezing room inside the refrigerator main body 51, 53 is a refrigerating room inside the refrigerator main body 51,
54 is a freezer compartment door, 55 is a refrigerating compartment door, 56 is a partition wall that separates the freezing compartment 52 and the refrigerating compartment 53, 57 is a freezing suction port for sucking air in the freezing compartment 52, and 58 is air for sucking air in the refrigerating compartment 53. Refrigerating chamber suction port, 59 is a freezing discharge port, 60 is a refrigeration cooler, 60a is a refrigeration fan, and 60b is a refrigeration discharge port. Reference numeral 61 is a refrigerating cooler, 62 is a refrigerating fan that circulates cold air, 63 is a cooler partition wall that separates the refrigerating cooler 61 and the freezer compartment 52, 64 is a trough, 65 is a drain outlet, and 66 is defrosting means. The glass tube heater of the freezing cooler 61
It is located below, which is near the.

Here, and the glass tube heater 66 is
Heater 70 and glass tube 71 in which iron-chromium wire is coiled
And a cap 72 made of silicone rubber, and the cap 72
And a lead wire 73 connected to the heater 70 on both end surfaces. 74 is a roof arranged above the glass tube 71,
The tabs 75 at the ends are engaged with and supported by the insertion portions 76 on the upper surface of the cap 72, and the evaporation noise generated when the defrost water directly drops on and contacts the glass tube heater 66.
Reference numeral 77 is a support member, and a rotation stopper portion 76a provided on a part of the cap 72 supports the glass tube heater 66 at a predetermined position.

Further, 68 is a compressor, and 69 is an evaporation dish provided on the upper part of the compressor. A flammable refrigerant such as isobutane is enclosed in the refrigeration cycle including the cooler 61 and the compressor 68.

The glass tube 71 is made of high-purity quartz glass or opaque quartz glass having a high heat-resistant temperature, and has a glass tube 71 having a higher strength than that of a conventional CFC-based refrigerant. .

Specifically, the outer diameter D1 of the glass tube 71 is 1
The plate thickness t1 is 0.5 mm and the plate thickness t1 is 1.2 to 2.0 mm. Therefore, the strength of the glass tube is assured by the measuring method shown in FIG. 8 even when a load of 100 to 400 N is applied, without causing damage or cracks. That is, in terms of strength, it is 2 to 4 times as strong as when a fluorocarbon refrigerant is applied.

Next, the operation will be described. Freezer 52,
Alternatively, when the refrigerating compartment 53 is cooled, the freezing cooler 6
1, or each cooling device is cooled by selectively flowing a refrigerant to the refrigerating cooling device 60. Then, the freezing fan 62 and the refrigerating fan 60a are actuated to operate the freezing chamber suction port 57 and the refrigerating chamber suction port 58 to raise the temperature of the freezing chamber 52 and the refrigerating chamber 53 to the freezing cooler 61 and the refrigerating cooler 60, respectively. To the freezing outlet 52 and the refrigerating outlet 60b, and cool air is sent to the freezing compartment 52 and the refrigerating compartment 53 to cool the freezing compartment 52 and the refrigerating compartment 53 independently.

Here, the air that exchanges heat with the freezing cooler 61 and the refrigerating cooler 60 is the freezing compartment door 54 and the refrigeration compartment door 55.
Inflow of high temperature outside air by opening and closing, freezing room 52, refrigerating room 53
Since the air is highly humidified by evaporation of water in the stored food, the refrigerating cooler 6 has a temperature lower than that of the air.
1. Moisture in the air becomes frost on the refrigerating cooler 60 to form frost. In this way, the refrigerator 61 for refrigeration and the refrigerator 6 for refrigeration
When 0 is frosted, heat transfer between the surfaces of the refrigerating cooler 61 and the refrigerating cooler 60 and the heat-exchanged air is obstructed as the amount of frost increases, and at the same time, the airflow resistance is reduced and the amount of airflow decreases. Passage rate decreases and cooling shortage occurs.

Therefore, the defrosting means 66 made of a glass tube heater is periodically energized via the lead wire 73 to the heater 70 made of an iron-chromium wire. Radiant heat radiated thereby causes the freezing cooler 61, the trough 64, and the drainage port 6
Melt the frost around 5 into water. Further, a part of the defrosted water thus melted falls directly to the trough 64, and the other part falls to the trough 64 while avoiding the defrosting means 66 by the roof 67 and is drained from the drainage port 65 to the outside of the refrigerator. The surface temperature of the glass tube 71 is below the ignition point temperature of the flammable refrigerant, and is controlled to a temperature about 100 ° C. lower than the ignition point in consideration of the safety factor.

Here, since the glass tube 71 is designed to have a higher strength than that when a conventional CFC-based refrigerant is applied, the glass tube 71 will not be damaged even if an external force is applied to the defrosting means 66. The risk of damage and exposure of the heater 20 is reduced. Therefore, even if the glass tube heater 66 is used as a defrosting means for a refrigerator using a flammable refrigerant in the refrigeration cycle, the risk of igniting the flammable refrigerant and becoming unsafe is drastically reduced, and safety is enhanced.

In this embodiment, the strength of the glass tube is set to 2 to 4 times. This is because the strength is most efficiently increased in the range of 2 to 4 times from the characteristic diagram showing the strength and cost performance (safety factor / cost) of the glass tube heater in FIG.

As a more specific form, the plate thickness t1 of the glass tube is 1.2 to 2.0, which is thicker than that when a CFC-based refrigerant is used.
The thickness is set to mm, and the range is such that the light transmittance is not reduced while the strength is increased by the plate thickness, so that radiant heat during defrosting is not hindered.

As described above, the glass tube 71 is arranged in the vicinity of the cooler 61 of the refrigeration cycle to which the flammable refrigerant is applied.
In the glass tube heater 66 including the heater 70, the caps 72 provided on both end surfaces of the glass tube 71, and the lead wire 73, the strength of the glass tube 71 is set to be stronger than that of the case where the fluorocarbon refrigerant is applied. , Glass tube heater 6
It is possible to prevent the flammable refrigerant from being ignited due to the breakage of 6, and it is possible to provide a highly safe refrigerator.

In the present embodiment, the description has been made assuming that the glass tube heater 66 is arranged in the vicinity of the freezing cooler 61 in the refrigerator that cools the refrigerating temperature zone and the freezing temperature zone independently. The glass tube heater 66 may be arranged near the refrigerating cooler 60. Thereby, the inside of the refrigerator is divided into a refrigerating temperature zone and a freezing temperature zone by a partition wall, a refrigerating cooler is provided in the refrigerating temperature zone, a freezing cooler is provided in the freezing temperature zone, and a flammable refrigerant is applied. In a refrigerator that cools the refrigerating temperature zone and the freezing temperature zone independently in the refrigeration cycle, it is possible to prevent ignition due to damage to the glass tube heater 66 arranged near the refrigerating cooler and the freezing cooler.

Further, in the present embodiment, the refrigerator in which the refrigerating temperature zone and the freezing temperature zone are independently cooled has been described, but in the refrigerator in which the refrigerating temperature zone and the freezing temperature zone are cooled by one cooler, the cooler Of course, even if the glass tube heater 66 is arranged in the vicinity of, the same effect as above can be obtained.

(Second Embodiment) FIG. 6 is a perspective view of a glass tube heater according to a second embodiment of the present invention. 7
Reference numeral 8 is a glass tube having an outer diameter D2 of 15 to 30 mm, preferably 20 to 25 mm. And the glass tube 78
The plate thickness t2 is 1.2 to 2.0 mm. further,
A second glass tube 79 is arranged inside the glass tube 78. The outer diameter D3 of the second glass tube 79 is 10.5 mm, which is the same as that of the glass tube when the fluorocarbon refrigerant is applied, and the plate thickness t3 is 1.0 to 1.1 mm, which is the same as the glass tube when the fluorocarbon refrigerant is applied. .

With the above structure, when the heater 80 arranged inside the glass tube 78 is energized, the glass tube 78
Since the surface area of is increased in proportion to the outer diameter, the surface temperature can be made lower than when the conventional CFC-based refrigerant is used. And
Since the outer diameter is within 30 mm at the maximum, it can be secured without making the installation space particularly large. Further, since the plate thickness t2 of the glass tube is set to be 1.2 to 2.0 mm, which is thicker than that when the CFC-based refrigerant is used, the range is set so that the light transmittance is not reduced while the strength is increased by the plate thickness. Does not interfere with radiant heat during frost. Therefore, it is possible to secure the installation space, enhance the strength, and secure the defrosting performance while lowering the surface temperature of the glass tube.

The surface temperature of the glass tube 78 can be further lowered by adopting a double structure in which the second glass tube 79 is arranged inside the glass tube 78. And further,
Even if the heater 80 is used as a defrosting means for a refrigerator using a flammable refrigerant in the refrigeration cycle, the glass tube heater 66 is applied because the heater 80 is less likely to be exposed due to damage to the glass tube 78 and the second glass tube 79. , The risk of becoming unsafe by igniting flammable refrigerant is drastically reduced, and safety is enhanced. Further, since the second glass tube 79 disposed inside can be a glass tube used when a conventional CFC refrigerant is used, it can be economically manufactured.

[0036]

As described above, according to the first aspect of the invention, the strength of the glass tube of the glass tube heater applied to the refrigeration cycle to which the flammable refrigerant is applied is used to the refrigeration cycle to which the fluorocarbon refrigerant is applied. 2 to the strength of the glass tube
Since it is set to four times, it is possible to prevent damage to the glass tube and prevent ignition of the refrigerant when the flammable refrigerant leaks, while maintaining the defrosting performance of the glass tube heater.

According to the second aspect of the invention, the plate thickness of the glass tube of the glass tube heater applied to the refrigeration cycle to which a flammable refrigerant is applied is set to 1.2 to 2.0 mm, so that the radiation transmittance is reduced. Without, the strength can be efficiently increased.

According to the third aspect of the invention, since the outer diameter of the glass tube of the glass tube heater applied to the refrigerating cycle to which a flammable refrigerant is applied is set to 15 to 30 mm, the surface temperature of the glass tube is lowered. The installation space can be secured and the strength can be increased.

In the invention described in claim 4, in the invention described in claim 1 or 3, since the glass tube has a multiple structure, the surface temperature of the glass tube is further lowered, and
The installation space can be secured and the strength can be increased.

A fifth aspect of the present invention is a cooling storage provided with the glass tube heater according to any one of the first to fourth aspects, in which flammable refrigerant leaks due to breakage of the glass tube heater. In this case, it is possible to prevent ignition and enhance the safety of the cooling storage.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a glass tube heater according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a glass tube of the glass tube heater according to the embodiment.

FIG. 3 is a characteristic diagram showing strength and cost performance (safety factor / cost) of the glass tube heater of the same embodiment.

FIG. 4 is a characteristic diagram showing plate thickness and strength of the glass tube heater of the same embodiment.

FIG. 5 is a cross-sectional view of a main part of a cooling storage provided with the glass tube heater according to the same embodiment.

FIG. 6 is a perspective view of a glass tube heater according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a main part of a conventional refrigerator.

FIG. 8 is a perspective view of a conventional defrost heater for a refrigerator.

FIG. 9 is a diagram showing a method for measuring the strength of a glass tube.

[Explanation of symbols]

51 refrigerator 66 glass tube heater 70, 80 heater 71, 78, 81 glass tubes 72 cap 73 lead wire

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shuzo Uemura             4-2-5 Takaidahondori, Higashi-Osaka City, Osaka Prefecture               Within Matsushita Cold Machinery Co., Ltd. F term (reference) 3K092 PP20 QA02 QB02 QB27 RA03                       RC02 RD10 VV31 VV33                 3L046 AA05 BA01 CA05 CA06 MA01                       MA04

Claims (5)

[Claims] 1. A glass tube heater, which is arranged near a cooler of a refrigeration cycle to which a flammable refrigerant is applied and has a heater wire covered with a glass tube. A glass tube heater characterized in that the strength of the glass tube is 2 to 4 times that of a glass tube used in a cycle. 2. A glass tube heater, which is arranged in the vicinity of a cooler of a refrigeration cycle to which a flammable refrigerant is applied and has a heater wire covered with a glass tube, wherein the glass tube has a plate thickness of 1.
A glass tube heater having a length of 2 to 2.0 mm. 3. A glass tube heater, which is arranged in the vicinity of a cooler of a refrigerating cycle to which a flammable refrigerant is applied and has a heater wire covered with a glass tube, wherein the outer diameter of the glass tube is 15
A glass tube heater characterized by having a thickness of up to 30 mm. 4. The glass tube heater according to claim 1, wherein the glass tube has a multiple structure. 5. A cooling storehouse comprising the glass tube heater according to claim 1. Description: