JP2001108352A - Defrosting device for refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hardly propagate flame even when a combustible refrigerant reaches a firing temperature and is fired and to decrease the possibility for combustion and explosion to occur. SOLUTION: 31 is taken as a defrosting heat-exchanger, 32 is taken as a heating type defrosting device for a refrigerator to defrost frost adhered to the defrosting heat-exchanger 31 and its periphery, 23 is taken as a heater wire, 24 is taken as a protection pipe, and 33 is taken as a support inner pipe formed of ceramic and a metal. By positioning the heater wire 23 in a very narrow space between the protection pipe 24 and the support inner pipe 33, flame is hardly propagated even when a combustible refrigerant reaches a firing temperature and firing occurs, and the possibility for combustion and explosion to occur is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defroster for a refrigerator using a combustible refrigerant.

[0002]

2. Description of the Related Art In recent years, HFC-based refrigerants have been used in accordance with Freon regulations. However, HFC-based refrigerants have become difficult to use due to problems such as global warming, and flammable refrigerants have been studied. In particular, products using a hydrocarbon-based refrigerant in a direct-cooled refrigerator having no defrosting device in the refrigerator have already been put to practical use overseas. However, in an intercooled refrigerator having a defrosting device, there is a possibility that the combustible refrigerant may burn and explode due to heating means for defrosting.

On the other hand, Japanese Patent Application Laid-Open No. 9-14811 discloses a refrigerator using a combustible refrigerant.
Japanese Patent Application Laid-Open No. H8-5417 discloses a defrosting apparatus.
Some publications are disclosed in Japanese Patent Laid-Open Publication No. H10-210.

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

FIG. 13 is a longitudinal sectional view of a main part of a conventional refrigerator. In FIG. 13, 1 is a refrigerator main body, 2 is a freezing room inside the refrigerator main body 1, 3 is a refrigerator room inside the refrigerator main body 1, 4 is a freezing room door, 5 is a refrigerator room door, 6 is a freezing room 2 And the refrigerating room 3.

[0007] Reference numeral 7 denotes a freezing compartment suction port for sucking air inside the freezing room 2, 8 denotes a refrigerating room suction port for sucking air inside the refrigerating room 3, 9 denotes a discharge port for discharging cool air, 10 denotes an evaporator, 1
1 is a fan for circulating cool air, 12 is an evaporator partition wall for separating the evaporator 10 and the freezing room 2, 13 is a gutter, 14 is a drain port,
Reference numeral 15 denotes a refrigerator defroster, 16 denotes a roof for preventing evaporation noise generated when defrost water directly drops on and comes into contact with the refrigerator defroster 15, 17 denotes a gutter 13 and the refrigerator defroster 1
5 is a metal bottom plate insulated and held between the metal bottom plates 5.

FIG. 14 is an enlarged view of the refrigerator defrosting device 15, and FIG. 15 is a cross-sectional view of the refrigerator defrosting device 15 taken along the line AA '.

Reference numeral 18 denotes a heater wire formed of a nichrome wire in a coil shape, reference numeral 19 denotes a glass tube, and reference numeral 20 denotes a sealing end of a heater made of silicon rubber or the like. The sealing end 20 is provided with a hole for preventing an increase in pressure due to expansion of internal air during heating. 21 is a lead wire for supplying power to the heater wire 18.

The operation of the defroster for a refrigerator configured as described above will be described below.

When cooling the freezer compartment 2 or the refrigerator compartment 3, a refrigerant flows through the evaporator 10 to cool the evaporator 10. Similarly, by the operation of the fan 11, the heated air in the freezer compartment 2 and the refrigerator compartment 3 is sent from the freezer compartment suction port 8 to the cooling compartment 20, where the heat is exchanged by the evaporator 10 and cooled. Cooling air is sent into the freezer compartment 2, and cool air is sent from the freezer compartment 2 to the refrigerator through a communication port (not shown).

Here, the air that exchanges heat with the evaporator 10 is caused by the inflow of high-temperature outside air due to the opening and closing of the freezer compartment door 4 and the refrigerator compartment door 5 and the evaporation of moisture generated from the stored food in the freezer compartment 2 and the refrigerator compartment 3. Since the air is humidified, the moisture in the air becomes frost and forms frost on the evaporator 10 which is lower in temperature than the air.

As described above, when the evaporator 10 becomes frosted, 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 decreases due to the ventilation resistance. In addition, the heat transmission rate decreases, and insufficient cooling occurs.

Therefore, the frost that has arrived near the evaporator 10, the gutter 13 and the drain port 14 is melted into water by the heat rays radiated when the nichrome wire of the refrigerator defroster 15 is energized.

Further, a part of the defrosted water thus melted falls directly on the gutter, and the other part falls on the gutter 13 avoiding the refrigerator defroster 15 by the roof 16 and is discharged from the drainage port 14 to the outside of the refrigerator. You. At this time, the defroster 15 for the refrigerator
Are partially reflected by the bottom plate 17 and scattered toward the evaporator 10.

In order to prevent the flammable refrigerant from being ignited by such a heater, it has been proposed to detect the leakage of the flammable refrigerant and shut off the entire power supply of the refrigerator including the refrigerator defroster 15. It has been done.

[0016]

However, in the above-described conventional configuration, in a refrigeration cycle using a flammable refrigerant, the flammable refrigerant leaks and diffuses inside the refrigerator and accumulates in the pipe of the defroster for the refrigerator. When the heater is energized, the heater temperature rises and finally reaches the ignition temperature of the flammable refrigerant, which may cause an explosion.

Further, in the above-described conventional configuration, since the flammable refrigerant has a relatively large latent heat, near the pipe of the evaporator where the flammable refrigerant accumulates, the amount of heat is insufficient only with radiant heat, so that defrosting cannot be performed sufficiently. In addition, insufficient cooling may cause poor cooling.

Further, the convective heat transfer in the above-described conventional refrigerator defroster occurs only indirectly by heating the air in the vicinity of the glass tube as a result of the heating of the glass tube. In some cases, there was a risk that the amount of heat would be insufficient,
As a result, defrosting could not be performed sufficiently, and there was a possibility that poor cooling would be caused due to an insufficient amount of heat exchange.

There is also a method of detecting the leakage of the flammable refrigerant and shutting off the entire power supply of the refrigerator including the refrigerator defroster. However, the refrigerant at the detection position is determined by the difference between the leakage position and the detection position. Before the concentration does not increase, the refrigerant concentration in the tube of the defroster for a refrigerator increases, and there is a possibility that the refrigerant may be ignited when heated.

Further, the heater wire is generally provided with an oxide film by a heat treatment, and after being plastically worked into a predetermined shape,
The shape is fixed again by the heat treatment, but an excessive force is applied to the heater wire due to an error in component accuracy or assembly, and as a result, the wire may be disconnected and reliability may be reduced. further,
When a flammable refrigerant is used, ignition or explosion may occur due to energy due to electric discharge due to such disconnection.

[0021] The present invention solves the conventional problems, and reduces the possibility of flammable refrigerant igniting in a glass tube of a defroster for a refrigerator and burning or exploding. Insufficient cooling caused by insufficient amount can be avoided. An object of the present invention is to provide a defroster for a refrigerator.

[0022]

To achieve this object, a refrigerator defroster according to the present invention comprises a refrigeration cycle evaporator using a combustible refrigerant, and a metal heater wire provided near the evaporator. In a heating means for defrosting, comprising a protective tube for accommodating the heater wire and an inner tube having a length in the major axis direction shorter than the protective tube inside the protective tube, the winding portion of the heater wire is protected by a protective tube. And the inner tube.

According to this invention, even if the flammable refrigerant enters the heater tube, the space with the heater wire is small, so that the flame propagation is not hindered and does not spread, and the amount of oxygen existing in the space is also limited. Therefore, the possibility of explosion can be kept very small.

[0024] The defrosting device for a refrigerator according to the present invention further comprises an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protection tube for housing the heater wire. In the heating means for defrosting, wherein an inner tube is provided inside the protective tube, a heater wire is located between the protective tube and the inner tube, and the inner tube has reflectivity and sandwiches the heating unit. And a reflector is provided at a location opposite to the evaporator.

According to the present invention, even if the flammable refrigerant enters the heater tube, the space with the heater wire is small, so that the flame is not propagated and does not spread, and the amount of oxygen is limited. The possibility is very small. In addition, since the inner tube has reflectivity, the radiant energy from the heater wire can be effectively transmitted to the evaporator, and the frost attached to the evaporator can be melted from the opposite direction by the reflector.

Further, the defrosting device for a refrigerator according to the present invention comprises an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protective tube for housing the heater wire. In the heating means for defrosting, a support inner rod having heat conductivity is inserted into the approximate center of a protective tube containing a heater wire, and the end of the support inner rod is brought into contact with an evaporator.

According to the present invention, even if the flammable refrigerant enters the heater tube, the space with the heater wire is small, so that the flame is not propagated and does not spread, and the amount of oxygen existing in the space is also limited. Therefore, the possibility of explosion can be kept very small. Furthermore, by inserting the inner support rod, the structural strength of the entire refrigerator defroster is increased, so that the glass tube is not damaged, and as a result, even if flammable refrigerant leaks without exposing the heater wire, an explosion may occur. It can be prevented from becoming an ignition source.

Similarly, a refrigerator defroster according to the present invention comprises a refrigeration cycle evaporator using a flammable refrigerant, a metal heater wire provided near the evaporator, and a protective tube containing the heater wire. In the heating means for defrosting, the lower part of the protective tube containing the heater wire is made of porous ceramic.

According to this invention, even if the flammable refrigerant enters the heater tube, the space with the heater wire is small, so that the flame propagation is not prevented and the flame does not spread, and the amount of oxygen is also limited. The possibility is very small. And, in the case of a small amount of refrigerant leakage, the concentration of the refrigerant in the refrigerator can always be kept to a minimum by the minute combustion in the pipe. Further, even if a large flame is generated, the flame cannot propagate when passing through the porous ceramic wall surface, and does not spread from the inside of the heater to the inside of the refrigerator.

Further, since air passes through the inside of the protection tube and the inside of the storage, even if an explosion occurs, the pressure rise is kept small, and the possibility of damage to the protection tube can be reduced.

The defroster for a refrigerator according to the present invention comprises an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protection tube for housing the heater wire. In the heating means for defrosting, a crimped body made of ceramic wool is inserted at the approximate center of a protective tube containing a heater wire.

According to the present invention, even if the flammable refrigerant enters the heater tube, the space with the heater wire is small, so that the flame propagation is not hindered and the flame does not spread, and the amount of oxygen is limited. The possibility is very small. In addition, by absorbing and radiating the heat rays, the ceramics can be converted into heat rays of a wavelength more efficient for defrosting and radiate, and furthermore, the heat rays can be radiated to the surroundings in a diffusely reflective manner, so that the evaporator periphery can be uniformly defrosted. At the same time, frost attached to the evaporator can be quickly melted.

[0033] The defrosting device for a refrigerator according to the present invention comprises an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protective tube for accommodating the heater wire. In the heating means for defrosting, wherein an inner pipe having a longer longitudinal axis than the protective pipe is provided inside the protective pipe, a connection terminal is provided at a position where a portion for taking out a heater wire is extended in a normal direction of the inner pipe. Is fixed.

According to the present invention, even if the flammable refrigerant enters the heater tube, the space with the heater wire is small, so that the flame propagation is not hindered and the flame does not spread, and the amount of oxygen existing in the space is also limited. Therefore, the possibility of explosion can be kept very small. Further, since the heater wire is extended in the normal direction, no extra force is applied to the heater wire, so that disconnection or the like hardly occurs and reliability can be improved.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An invention according to claim 1 of the present invention accommodates an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and the heater wire. In a heating means for defrosting, comprising a protection tube and an inner tube having a length in a long axis direction shorter than the protection tube inside the protection tube, a winding portion of the heater wire is disposed between the protection tube and the inner tube. Even if the flammable refrigerant enters the heater tube, the space with the heater wire is small and the flame propagation is not obstructed, it does not spread, and the oxygen amount is also limited. It has the effect of holding down the possibility of explosion very small.

According to a second aspect of the present invention, there is provided an evaporator for a refrigeration cycle using a flammable refrigerant, a metal heater wire provided near the evaporator, and a protective tube for housing the heater wire.
In the heating means for defrosting, wherein an inner tube is provided inside the protective tube, a heater wire is located between the protective tube and the inner tube, and the inner tube has reflectivity and sandwiches the heating unit. The reflector is provided at the location opposite to the evaporator, and even if the flammable refrigerant enters the heater pipe, the space with the heater wire is small and the flame propagation is hindered and spreads It has the effect of keeping the possibility of explosion very small because the amount of oxygen is also limited.
In addition, since the inner tube has reflectivity, the radiant energy from the heater wire can be effectively transmitted to the evaporator, and the frost adhering to the evaporator from the opposite direction can be melted by the reflection plate.

According to a third aspect of the present invention, there is provided a defrosting apparatus comprising an evaporator of a refrigeration cycle using a flammable refrigerant, a metal heater wire provided in the vicinity of the evaporator, and a protective tube containing the heater wire. In the heating means, a support inner rod having thermal conductivity is inserted into the approximate center of a protective tube containing a heater wire, and an end of the support inner rod is brought into contact with an evaporator. Even if the flammable refrigerant enters the heater tube, the space with the heater wire is small and the flame propagation is not prevented and it does not spread, and the amount of oxygen is limited, so that the possibility of explosion can be suppressed very small. In addition, since the structural strength is increased, the glass tube is not broken, and as a result, even if the combustible refrigerant leaks without exposing the heater wire, it has an effect of preventing the explosion from becoming an ignition source.

According to a fourth aspect of the present invention, there is provided a defrosting apparatus comprising an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided in the vicinity of the evaporator, and a protective tube containing the heater wire. Wherein the lower part of the protective tube containing the heater wire is made of porous ceramic, and the convective heat transfer in the ceramic tube heater is based on the result that the glass tube is heated and the heater tube. The direct effect of heating the air inside and coming out of the refrigerator occurs synergistically, and even when a flammable refrigerant is used, there is no shortage of heat for melting frost, and as a result, the removal Frost can be sufficiently performed, and there is an effect of eliminating the possibility of insufficient cooling due to a shortage of heat exchange. The circulation of the air can also prevent the heater wire from becoming higher than the ignition temperature of the combustible refrigerant.

According to a fifth aspect of the present invention, there is provided a defrosting apparatus comprising an evaporator of a refrigeration cycle using a flammable refrigerant, a metal heater wire provided in the vicinity of the evaporator, and a protective tube containing the heater wire. In the heating means, a crimped body made of ceramic wool is inserted approximately in the center of the protective tube in which the heater wire is inserted, so that even if the combustible refrigerant enters the heater tube, the space with the heater wire is provided. Small, which prevents the spread of flames and does not spread, and also limits the possibility of explosion due to the limited amount of oxygen, and the ceramic absorbs and emits heat rays to improve defrosting efficiency. It can be radiated by converting it into heat rays of a specific wavelength, and has the effect of quickly melting the frost attached to the evaporator.

According to a sixth aspect of the present invention, there is provided an evaporator for a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, a protection tube for housing the heater wire, and the protection tube. In the defrosting heating means provided with an inner tube having a longer longitudinal direction than the protective tube inside the protection tube, a connection terminal is provided at a position where a winding wire take-out portion of the heater wire is extended in a normal direction. Even if the flammable refrigerant enters the heater tube, the space with the heater wire is small and the flame propagation is not hindered, it does not spread, and the amount of oxygen existing in the space is also limited. The possibility of explosion is very small. Further, since the heater wire is extended in the normal direction, an extra force is not applied to the heater wire, so that the heater wire is less likely to be disconnected and has an effect of improving reliability.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The same components as those in the related art are denoted by the same reference numerals, and detailed description is omitted.

(Embodiment 1) FIG. 1 is an enlarged view of a refrigerator defrosting apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a longitudinal sectional view taken along the line BB '.

1 and 2, reference numeral 22 denotes a heating-type refrigerator defroster for defrosting frost adhering to the evaporator 10 and its surroundings. 23 is a coiled heater wire made of nickel chromium or iron chrome, 24 is a protection tube made of glass or the like, and 25 is an inner tube made of glass or ceramic. The winding portion of the heater wire 23 is composed of the protective tube 24 and the inner tube 2.
Located in the space between 5. In actual assembly, after the heater wire 23 is inserted into the protection tube 24, the heater wire 23 can be easily inserted by attaching a conical insertion jig to the tip of the inner tube 25.
Reference numeral 26 denotes a fixing plate made of metal having a spring property to prevent the inner tube from shifting.

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

When the refrigerator cools normally and a given time elapses, the fan 1 is used to remove the frost from the evaporator 10.
After 1 stops and the circulation of the refrigerant in the evaporator 10 stops, the refrigerator defrosting device 22 operates. Then, the completion of defrosting is detected by detecting the completion of defrosting by means of a defrost detecting means (not shown) for detecting a rise in temperature, etc., and the defrosting device 22 for the refrigerator is stopped to complete the defrosting. The temperature of the device 22 decreases. At this time, if the flammable refrigerant is leaking into the refrigerator, the flammable refrigerant is sucked into the protection tube 24 as the refrigerator defrost device 22 is cooled. Normally, after a certain period of time has elapsed and the temperature of the heater wire 23 has risen again by the operation of the defroster 22 for the refrigerator, the temperature reaches the ignition temperature of the combustible refrigerant, which may cause ignition, combustion, and explosion. However, in the present invention, since the distance between the protective tube 24 and the inner tube 25 is extremely narrow, even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is reduced.

Further, since the protective tube 24 and the inner tube 25 have a double structure, the structural strength of the refrigerator defrosting device 22 as a whole is increased, so that it is needless to say that the bending stiffness is improved and cracks are less likely to occur.

If the both ends of the inner tube 25 are sealed and in a reduced pressure state, the amount of flammable refrigerant staying in the refrigerator defrosting device 22 is reduced, and the power of combustion and explosion is reduced. it can.

(Embodiment 2) FIG. 3 is an enlarged view of a refrigerator defrosting apparatus according to Embodiment 2 of the present invention, and FIG. 4 is a longitudinal sectional view taken along the line CC '.

In FIGS. 3 and 4, reference numeral 27 denotes a heating type defroster for a refrigerator for defrosting frost adhering to the evaporator 10 and its periphery. 23 is a coiled heater wire made of nickel chrome or iron chrome, etc., 24 is a protective tube made of glass or the like, 28 is an inner tube made of glass, ceramic, metal or the like, and 29 is an outer surface of the inner tube 28. It is a reflection film of a ceramic type or the like that reflects the formed heat rays. The heater wire 23 is located in a space between the protection tube 24 and the inner tube 28. 2
Reference numeral 6 denotes a fixing plate made of metal having a spring property to prevent the inner tube from shifting. Reference numeral 30 denotes a reflector provided at a position opposite to the evaporator 10 with the heating-type refrigerator defroster 27 interposed therebetween.

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

When the refrigerator cools normally and a given time elapses, the fan 1 is used to remove the frost from the evaporator 10.
After the stop of 1 and the circulation of the refrigerant in the evaporator 10 stop, the refrigerator defrosting device 27 operates. Defroster for refrigerator 27
When the heater wire 23 inside is heated, it emits a heat ray.
On the other hand, since a reflective film 29 made of a ceramic or the like that reflects heat rays is formed on the surface of the inner tube 28, heat rays can be emitted more efficiently. Further, since the reflecting plate 30 is provided at a position opposite to the evaporator 10 with the refrigerator defrosting device 27 interposed therebetween, the evaporator 1 reflects heat rays more efficiently.
The frost of 0 can be melted, the energization time can be shortened, and efficient and energy-saving defrosting can be performed. And a defrost detecting means (not shown) for detecting a rise in temperature.
As a result, the completion of the defrosting is detected, the energization of the refrigerator defrosting device 27 is stopped, the defrosting is completed, and the temperature of the refrigerator defrosting device 27 decreases. At this time, if the flammable refrigerant is leaking into the refrigerator, the flammable refrigerant is sucked into the protection tube 24 as the refrigerator defroster 27 is cooled. However, in the present invention, since the distance between the protective tube 24 and the inner tube 25 is extremely narrow, even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is reduced.

Also, since the protective tube 24 and the inner tube 28 have a double structure, the structural strength of the refrigerator defrosting device 22 as a whole is increased, so that it is needless to say that the bending stiffness is improved and the refrigerator is hardly cracked.

If the both ends of the inner tube 28 are sealed and in a reduced pressure state, the amount of the flammable refrigerant staying in the refrigerator defroster 27 is reduced, and the power of combustion and explosion is reduced. it can.

It is needless to say that the shape of the reflection plate is approximately half the shape of an ellipse.

(Embodiment 3) FIG. 5 is an enlarged view of a refrigerator defrosting apparatus according to Embodiment 3 of the present invention, and FIG. 6 is a longitudinal sectional view cut along a DD 'section.

5 and 6, reference numeral 31 denotes a defrost heat exchanger. Reference numeral 32 denotes a heating-type refrigerator defroster for defrosting the frost adhering to the defrost heat exchanger 31 and its surroundings.
23 is a coiled heater wire made of nickel chromium or iron chrome, 24 is a protective tube made of glass or the like, and 33 is a support inner rod made of ceramic or metal. The heater wire 23 is located in a space between the protection tube 24 and the inner support rod 33. In the actual assembly, the heater wire 23 is connected to the support inner rod 33.
It can be inserted at the same time, and the assemblability is very high. Support inner rod 33
Is passed through the protective tube 24 and the protective cap 34, is bent and is fixed in contact with the defrost heat exchanger 31. Reference numeral 26 denotes a fixing plate made of metal having a spring property to prevent the inner tube from shifting.

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

When the refrigerator cools normally and an arbitrary time elapses, the fan 11 stops to defrost the frost in the defrost heat exchanger 31 and the refrigerant in the defrost heat exchanger 31 stops flowing. After that, the refrigerator defrosting device 32 operates.

The heater wire 2 in the refrigerator defroster 32
When 3 is heated, it emits heat rays. On the other hand, the support inner rod 33
Is also heated and transmits heat to the defrost heat exchanger 31 by heat conduction. Therefore, heat can be efficiently transmitted, the frost of the defrost heat exchanger 31 can be melted, and the energization time can be shortened, and efficient and energy-saving defrost can be performed.

Then, the completion of defrosting is detected by the defrost detection means (not shown) which detects a rise in temperature and the like. The temperature of the use defrosting device 32 decreases. At this time,
If the flammable refrigerant leaks into the refrigerator, the refrigerator defroster 3
As the 2 is cooled, the combustible refrigerant is sucked into the protection tube 24. Normally, when a certain period of time elapses and the temperature of the heater wire 23 rises again by operating the refrigerator defroster 32, the temperature reaches the ignition temperature of the combustible refrigerant, which may cause ignition, combustion, and explosion. However, in the present invention, the space between the protection tube 24 and the support inner rod 33 is extremely narrow, and the space of the fin of the support inner rod 33 is also extremely small. Therefore, even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is further reduced.

Further, since the protective tube 24 and the supporting inner rod 33 have a double structure, the structural strength of the refrigerator defrosting device 32 as a whole is increased, so that the bending rigidity is improved and it is difficult to crack. .

The shape of the inner support rod is not limited to the illustrated shape, but may be any of a round shape, a cross shape, a star shape, a flat shape, and the like, as long as it satisfies the requirements for supporting the heater wire 23. No.

(Embodiment 4) FIG. 7 is an enlarged view of a refrigerator defrosting apparatus according to Embodiment 4 of the present invention, and FIG. 8 is a longitudinal sectional view taken along the line EE '.

7 and 8, reference numeral 35 denotes a heating-type refrigerator defroster for defrosting frost adhering to the evaporator 10 and its surroundings. 23 is a coiled heater wire made of nickel chromium, iron chromium or the like, and 36 is a protective tube formed by co-extrusion of coarse ceramic and dense ceramic. The protection tube 36 is fixed so that the rough ceramic portion is located below. Reference numeral 37 denotes an inner tube made of a glass tube, a ceramic tube, a metal tube, or the like. The heater wire 23 is located in a space between the protection tube 36 and the inner tube 37. Reference numeral 26 denotes a fixing plate made of metal having a spring property to prevent the inner tube from shifting.

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

The refrigerator cools normally, and after an arbitrary time elapses, the fan 1
After 1 stops and the circulation of the refrigerant in the evaporator 10 stops, the refrigerator defrosting device 22 operates.

The heater wire 2 in the refrigerator defroster 35
When 3 is heated, it emits heat rays. On the other hand, in the protective tube 36, the heated air leaks from the lower coarse ceramic portion into the storage. The convection heat transfer efficiently heats the evaporator 1
The frost can be transported to zero, the frost can be thawed, the energization time can be shortened, and efficient and energy-saving defrosting can be performed.

Then, the completion of defrosting is detected by the defrosting detecting means (not shown) for detecting a rise in temperature and the like. The temperature of the use defrost device 35 decreases. At this time,
If the flammable refrigerant leaks into the refrigerator, the refrigerator defroster 3
As 5 cools, flammable refrigerant is sucked into protection tube 36.

Normally, when a certain period of time has elapsed after that, and the temperature of the heater wire 23 rises again after the defrosting device 35 for the refrigerator operates, the ignition temperature of the combustible refrigerant may be reached and ignition, combustion, and explosion may occur. However, in the present invention, since the protective tube 36 is made of coarse ceramics, even if it reaches the ignition temperature of the flammable refrigerant and ignites, it is difficult for the flame to propagate in the refrigerator, so that the possibility of combustion and explosion is reduced. In addition, since the air inside the protection tube is heated and goes out of the storage, the temperature of the heater wire can be prevented from being higher than the ignition temperature of the flammable refrigerant.

(Embodiment 5) FIG. 9 is an enlarged view of a refrigerator defrosting apparatus according to Embodiment 5 of the present invention, and FIG. 10 is a longitudinal sectional view cut along the FF 'section.

9 and 10, reference numeral 38 denotes an evaporator 10;
This is a heating-type refrigerator defrosting device for defrosting frost adhering to and around the refrigerator. 23 is a coiled heater wire made of nickel chromium or iron chrome, etc., 24 is a protective tube made of glass or the like, 39 is a crimped body made of ceramic wool or the like and formed into a substantially cylindrical shape by compressing or needle-punching a nonwoven fabric. It is. The heater wire 23 is located in a space between the protection tube 24 and the crimp body 39. In the actual assembly, the heater wire 23 is tightly wound around the crimping body 39 and inserted, and then the heater wire 23 spreads along the protective tube 24. 2
Reference numeral 6 denotes a fixing plate made of a metal having a spring property to prevent the crimping body 39 from shifting. The term "joining by needle punching" means that fibers are entangled and joined by inserting ceramic wool or the like with a sharp hooking needle and then pulling out.

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

The refrigerator cools normally, and after an arbitrary time elapses, the fan 1
After 1 stops and the circulation of the refrigerant in the evaporator 10 stops, the refrigerator defrosting device 38 operates. Then, the completion of defrosting is detected by detecting the completion of defrosting by defrosting detection means (not shown) for detecting a rise in temperature, and the defrosting operation of the refrigerator defrosting device 38 is stopped. The temperature of the device 38 decreases. At this time, if the flammable refrigerant is leaking into the refrigerator, the flammable refrigerant is sucked into the protection tube 24 as the refrigerator defroster 38 is cooled. Normally, after a certain period of time has elapsed and the temperature of the heater wire 23 rises again after the refrigerator defrosting device 38 has been activated, the temperature reaches the ignition temperature of the combustible refrigerant, which may cause ignition, combustion, and explosion. However, in the present invention, since the distance between the protective tube 24 and the crimping body 39 is extremely narrow,
Even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is reduced.

By mixing zirconia or the like in the ceramic fiber, the far infrared heat dose can be increased and the defrosting efficiency can be improved.

(Embodiment 6) FIG. 11 is an enlarged view of a refrigerator defrosting apparatus according to Embodiment 6 of the present invention, and FIG. 12 is GG '.
FIG. 4 is a longitudinal sectional view cut in a section.

11 and 12, reference numeral 40 denotes the evaporator 1
This is a heating-type refrigerator defroster for defrosting frost adhering to 0 and its surroundings. 41 is a coiled heater wire made of nickel chromium or iron chrome, 42 is a protection tube made of glass or the like, 43 is an inner tube made of glass or ceramic, and has a longer axial length than the protection tube 42. long. 4
Reference numeral 4 denotes a sealing end of the heater made of silicon rubber or the like. The sealing end 44 is provided with a hole through which the inner tube 43 can penetrate, and at the same time, a small hole for preventing a pressure increase due to expansion of the internal air during heating. Reference numeral 45 denotes a lead wire for supplying power to the heater wire 41. 46 is a connection terminal that connects the heater wire 41 and the lead wire 45 by crimping, welding, or the like,
It is fixed at a position that is normal to the heater wire.

The refrigerator configured as described above
The operation will be described below.

When the refrigerator cools normally and passes an arbitrary time, the fan 1 is used to remove the frost from the evaporator 10.
After 1 stops and the refrigerant circulation of the evaporator 10 stops, the refrigerator defrosting device 40 operates. Then, the completion of defrosting is detected by the defrost detection means (not shown) which detects a rise in temperature, and the energization of the refrigerator defrosting device 40 is stopped to complete the defrosting. The temperature of the device 40 decreases. At this time, if the flammable refrigerant is leaking into the refrigerator, the flammable refrigerant is sucked into the protective tube 42 as the refrigerator defroster 40 is cooled. Normally, when a certain period of time elapses and the temperature of the heater wire 41 rises again by operating the refrigerator defroster 40, the temperature reaches the ignition temperature of the combustible refrigerant, which may cause ignition, combustion, and explosion. However, in the present invention, since the distance between the protection tube 42 and the inner tube 43 is extremely narrow, the flame does not easily propagate even if the ignition temperature of the combustible refrigerant reaches and ignites, so that the possibility of combustion and explosion is reduced.

Further, since the protective tube 42 and the inner tube 43 have a double structure, the structural strength of the refrigerator defrosting apparatus 40 as a whole is increased, so that it is needless to say that the bending stiffness is improved and cracks are less likely to occur. Further, since the heater wire is extended in the normal direction, an unreasonable force generated due to a component accuracy or an assembly error is not applied to the heater wire, so that disconnection or the like hardly occurs, and thus the reliability is improved. Furthermore, when a flammable refrigerant is used, there is also an effect of reducing the possibility of ignition or explosion due to the energy of electric discharge due to such disconnection.

Since the inner tube 43 penetrates through the sealing end 44, the heated air flows inside the inner tube 43, and it is possible to promote the melting of the frost of the evaporator 10 by the convection effect. it can.

[0081]

As described above, the first aspect of the present invention provides an evaporator for a refrigeration cycle using a flammable refrigerant,
Heating for defrosting provided with a metal heater wire provided in the vicinity of the evaporator and a protection tube for housing the heater wire, and an inner tube having a length in the major axis direction shorter than the protection tube inside the protection tube. In the means, the winding portion of the heater wire is positioned between the protective tube and the inner tube, so that even if the temperature reaches the ignition temperature of the flammable refrigerant and the flame is difficult to propagate even if ignited, it burns and explodes. This has the effect of reducing the possibility. Furthermore, since the protective tube and the inner tube have a double structure, the refrigerator defrosting device as a whole
Since the structural strength is increased, there is also an effect that the bending stiffness is improved and cracks are hardly caused.

Further, the invention according to claim 2 is characterized in that an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator and a protective tube for accommodating the heater wire, In the heating means for defrosting in which the inner tube is provided inside the protective tube, the heater wire is located between the protective tube and the inner tube, and the inner tube has a reflective property, and the heating wire is interposed therebetween. Since the reflector is provided on the opposite side of the evaporator, it reflects the heat rays more efficiently, can melt the frost of the evaporator, shortens the energization time and is more efficient. Energy-saving defrosting can be performed, and even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is reduced. Further, since the protective tube and the inner tube have a double structure, the structural strength of the entire defrosting device for a refrigerator is increased, so that the bending rigidity is hardly broken.

[0083] The invention according to claim 3 is a refrigerating cycle evaporator using a combustible refrigerant, a metal heater wire provided in the vicinity of the evaporator, and a protective tube for accommodating the heater wire. In the heating means for frost, a support inner rod having thermal conductivity is inserted into the approximate center of a protective tube containing a heater wire, and the end of the support inner rod is brought into contact with an evaporator. However, even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is further reduced.

Further, according to the present invention, there is provided an evaporator for a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protection tube for containing the heater wire. In the heating means for frost, the lower part of the protective tube containing the heater wire is made of porous ceramic, so that frost can be efficiently melted by convection heat transfer, and the energizing time can be shortened and the efficiency can be shortened. In addition, it is possible to perform efficient and energy-saving defrosting, and even if the flammable refrigerant reaches the ignition temperature and ignites, it is difficult for the flame to propagate through the porous protection tube into the inside of the storage, thereby reducing the possibility of combustion and explosion. Furthermore, since air passes through the inside of the protection tube and the inside of the refrigerator, the pressure rise is small even when exploding, and there is also an effect that the possibility of damage to the protection tube can be reduced.

Further, according to the present invention, there is provided a refrigerating cycle evaporator using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protective tube for accommodating the heater wire. In the heating means for frost, since a crimped body made of ceramic wool is inserted approximately at the center of the protective tube containing the heater wire, it is difficult for the flame to propagate even if the ignition temperature of the flammable refrigerant is reached and ignited. This has the effect of reducing the possibility of combustion and explosion. Further, the use of an irregularly shaped crimped body results in very high assemblability.

Further, according to the present invention, there is provided an evaporator of a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, and a protective tube for housing the heater wire, In the defrosting heating means provided with an inner tube having a longer longitudinal axis than the protective tube inside the protective tube, a connection terminal is provided at a position where a take-out portion of a winding of a heater wire is extended in a normal direction. Since the flame is fixed, the flame reaches the ignition temperature of the flammable refrigerant, and even if ignited, it is difficult for the flame to propagate, so that the possibility of combustion and explosion is reduced. further,
Since the protective tube and the inner tube have a double structure, the structural strength of the entire refrigerator defrosting device is increased, so that the bending stiffness is also less likely to be broken. Further, since the heater wire is extended in the normal direction, an excessive force is hardly applied to the heater wire to cause a disconnection or the like, so that reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a defroster for a refrigerator.

FIG. 2 is a cross-sectional view taken along a B-B ′ vertical cross section of FIG. 1;

FIG. 3 is a front view of a defroster for a refrigerator.

FIG. 4 is a sectional view taken along a vertical section taken along line C-C ′ of FIG. 3;

FIG. 5 is a front view of a defroster for a refrigerator.

FIG. 6 is a cross-sectional view taken along a D-D ′ vertical cross section of FIG. 5;

FIG. 7 is a front view of a defroster for a refrigerator.

FIG. 8 is a sectional view taken along a vertical section taken along line E-E ′ of FIG. 7;

FIG. 9 is a front view of a defrosting device for a refrigerator.

FIG. 10 is a cross-sectional view taken along a vertical section taken along line F-F ′ of FIG. 9;

FIG. 11 is a front view of a defroster for a refrigerator.

FIG. 12 is a cross-sectional view taken along the line G-G ′ of FIG. 11;

FIG. 13 is a partial sectional view of a conventional refrigerator.

FIG. 14 is a front view of the defrosting device of FIG.

FIG. 15 is a cross-sectional view taken along a line A1-A1 ′ of FIG. 14;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Evaporator 22, 27, 32, 35, 38, 40 Defroster for refrigerators 23, 41 Heater wire 24, 36, 42 Protective tube 25, 28, 37, 43 Inner tube 29 Reflective film 30 Reflector 31 Defrosting heat Exchanger 33 Support inner rod 39 Crimper 45 Connection terminal

Claims (6)

[Claims] An evaporator for a refrigeration cycle using a combustible refrigerant, a metal heater wire provided near the evaporator, a protection tube for housing the heater wire, and a protection tube inside the protection tube. A defrosting heating means provided with an inner tube having a short length in the major axis direction, wherein a winding portion of the heater wire is positioned between the protective tube and the inner tube. apparatus. 2. An evaporator for a refrigeration cycle using a flammable refrigerant, a metal heater wire provided in the vicinity of the evaporator, a protection tube for housing the heater wire, and an inner tube inside the protection tube. In the provided defrosting heating means, the heater wire is located between the protective tube and the inner tube, and the inner tube has reflectivity,
A defroster for a refrigerator, wherein a reflection plate is provided at a position opposite to the evaporator with respect to the heating means. 3. A defrosting heat exchanger for a refrigeration cycle using a combustible refrigerant, a metal heater wire provided in the vicinity of the defrosting heat exchanger, and a protective tube containing the heater wire. In the heating means, a support inner rod having thermal conductivity is inserted into the approximate center of the protective tube containing the heater wire, and the end of the support inner rod is brought into contact with a defrost heat exchanger. Defroster for refrigerator. 4. A defrosting heating means comprising: an evaporator of a refrigeration cycle using a combustible refrigerant; a metal heater wire provided in the vicinity of the evaporator; and a protection tube for accommodating the heater wire. A defroster for a refrigerator, wherein a lower portion of a protective tube in which a wire is inserted is made of a porous ceramic. 5. A defrosting heating means comprising: an evaporator of a refrigeration cycle using a combustible refrigerant; a metal heater wire provided in the vicinity of the evaporator; and a protection tube for accommodating the heater wire. A defroster for a refrigerator, characterized in that a crimped body made of ceramic wool is inserted into the approximate center of a protective tube in which a wire is inserted. 6. An evaporator for a refrigeration cycle using a flammable refrigerant, a metal heater wire provided near the evaporator, a protection tube for storing the heater wire, and a protection tube inside the protection tube. In the defrosting heating means provided with an inner pipe having a long length in the major axis direction, a connection terminal is provided at a position where a portion for taking out a heater wire is extended in a normal direction to the inner pipe. Refrigerator defroster.