JP3404387B2 - refrigerator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator provided with a defrost heater for defrosting frost attached to and deposited on an evaporator of a refrigeration cycle in which a flammable refrigerant is sealed.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 8-54172 discloses a conventional refrigerator having a defrost heater.

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

FIG. 16 is a vertical sectional view of a main part of a conventional refrigerator. In FIG. 16, 1 is a refrigerator body, 2 is a freezer compartment inside the refrigerator body 1, 3 is a refrigerator compartment inside the refrigerator body 1, 4 is a refrigerator compartment door, 5 is a refrigerator compartment door, and 6 is a refrigerator compartment 2. A partition wall that separates the refrigerator compartment 3 from the refrigerator compartment, 7 a freezer compartment inlet for sucking air in the freezer compartment 2, 8 a refrigerating compartment inlet for sucking air in the refrigerating compartment 3, 9 an outlet for discharging cold air, 10 a Evaporator, 11 is a fan for circulating cold air, 12 is evaporator 10
And an evaporator partition wall for partitioning the freezer compartment 2, 13 a trough, 14 a drain port, 15 a defrost heater in which a nichrome wire is coiled and covered with a glass tube, 16 is a defrost water defrost heater 15 A roof 17 is provided between the trough 13 and the defrosting heater 15 and is insulated and held to prevent evaporation noise generated when it is directly dropped on and brought into contact with the bottom plate 17.

Regarding the refrigerator constructed as described above,
The operation will be described below. When cooling the freezer compartment 2 or the refrigerating compartment 3, the refrigerant flows through the evaporator 10 to cool the evaporator 10. Similarly, by the operation of the fan 11,
The temperature-raising air in the freezing compartment 2 or the refrigerating compartment 3 is sent to the cooling compartment from the freezing compartment suction inlet 7 or the refrigerating compartment suction inlet 8, and is heat-exchanged by the evaporator 10 to be cooled and cooling air is discharged from the discharge outlet 9 to the freezing compartment 2. Then, cold air is sent from the freezer compartment 2 to the refrigerating compartment 3 through a communication port (not shown). Here, the air that exchanges heat with the evaporator 10 is highly humid due to the inflow of high-temperature outside air by opening and closing the freezer compartment door 4 and the refrigerator compartment door 5 and the evaporation of water contained in the food stored in the freezer compartment 2 and the refrigerator compartment 3. Since the air is liquefied, the moisture in the air becomes frost on the evaporator 10, which is lower in temperature than the air, and is frosted / accumulated. Heat transfer is impeded, and the air flow resistance becomes reduced to reduce the air flow rate, so that the heat transfer rate decreases and insufficient cooling occurs. Therefore, the nichrome wire of the defrost heater 15 is energized before the cooling becomes insufficient. When energization of the nichrome wire is started, heat rays are radiated from the nichrome wire to the evaporator 10 and peripheral parts. At this time, a part of the heat ray radiated to the bottom plate 17 is reflected by the heater wire from the shape of the bottom plate 17,
Others are reflected toward the evaporator 10 and other peripheral components. As a result, the frost that has adhered to the evaporator 10, the trough 13, and the drainage port 14 is melted in water. The defrosted water thus melted is partly dropped directly into the tub 13, and the other part is dropped into the tub 13 while avoiding the defrost heater 15 by the roof 16 and discharged from the drainage port 14 to the outside of the refrigerator.

[0006]

However, in the above-mentioned conventional structure, the glass surface temperature of the defrost heater 15 is very high, not to mention the surface of the nichrome wire, and the bottom plate 17 is the defrost heater. Since the part of the heat ray radiated from the defrosting heater 15 is in the vicinity of 15 and is reflected again to the defrosting heater 15, the temperature of the glass tube rises abnormally and becomes higher than the ignition temperature of the flammable refrigerant.

From the above, when the flammable refrigerant is used as the refrigerant, even if the flammable refrigerant leaks from the pipe installed in the portion communicating with the evaporator 10 or the inside of the refrigerator, the defrost heater- There was a problem that it was necessary to prevent it from becoming an ignition source by energizing 15.

In view of the above problems, it is an object of the present invention to provide a refrigerator that is highly safe even when defrosting is performed in an environment where flammable refrigerant leaks into the installation atmosphere of the defrost heater.

[0009]

The invention according to claim 1 of the present invention is provided with a defrosting heater for removing frost adhered and accumulated on an evaporator of a refrigeration cycle enclosing a combustible refrigerant by heating, The defrost heater includes a glass tube, a heater wire made of a metal resistor installed inside the glass tube, and
A plug for forming a wire insertion hole and covering both end openings of the glass tube; and an end of the heater wire passing through the lead wire insertion hole.
Lead wire connected to the heater, the heater wire and the lead wire.
Is provided at the connection with the cable and is held by the plug
A positioning plate that prevents the connecting part from moving, and the surface temperature of the glass tube is adjusted to be less than the ignition temperature of the flammable refrigerant, and the shape of the stopper and the positioning plate is adjusted.
The size of the gap created is determined by the flammable refrigerant and the plug.
The heater wire side through the gap formed with the placement plate
Formed by the stopper and the positioning plate even when the fire enters
The gap is set so that the flame does not propagate , and the flammable refrigerant that leaks into the cabinet is blocked by the stopper and the positioning plate.
Even if it enters the glass tube through the gap formed and ignites due to the heat generated by the heater wire, the flame is formed by the plug and the positioning plate.
The safety is ensured because it does not propagate through the gaps .

Next, the invention according to claim 2 is provided with a defrosting heater for removing frost adhered / accumulated on the evaporator of the refrigeration cycle enclosing a combustible refrigerant by heating, and the defrosting heater is the first defrosting heater. Glass tube, a second glass tube installed so as to cover the outer periphery of the first glass tube, a heater wire made of a metal resistor installed inside the first glass tube, and a lead wire insertion hole. A plug formed to cover the openings at both ends of the first glass tube and the second glass tube; and the lead.
The lead connected through the wire insertion hole to the end of the heater wire.
Lead wire and the connection between the heater wire and the lead wire.
And is held by the stopper to prevent the connection part from moving.
And a positioning plate for preventing the stopper and the positioning plate.
The size of the gap formed by the flammable refrigerant and the plug
The heater passes through a gap formed with the positioning plate.
-Even if it enters the line side and ignites, the plug and the positioning plate
The size of the gap formed by <3> is set so that flame does not propagate , and by making the glass tube a double structure, the surface temperature of the second glass tube is kept below the ignition temperature of the flammable refrigerant. The flammable refrigerant that has been maintained and leaked into the refrigerator is formed by the stopper and positioning plate.
Even if it enters the first glass tube through the gap formed and ignites due to the heat generated by the heater wire, the flame is formed by the plug and the positioning plate.
Safety is ensured because it does not propagate through the created gap .

Next, the invention described in claim 3 is the same as claim 1.
In the invention described in item 2 or 2, the glass tube is viewed from the end face side.
A cross section at an arbitrary position of the gap formed by the stopper and the positioning plate
Is obtained by the product to the maximum 57 square millimeters which
Flammable refrigerant leaked by the heater wire ignites
However, the flame does not propagate through the gap formed between the stopper and the positioning plate.
Safety is ensured because seeding is not possible.

Next, the invention according to claim 4 is the same as claim 1.
In the invention according to Item 2 or 2 , the positioning plate is provided with a vent hole.
Put the edge of the positioning plate inside the stopper, and
All SANYO movement of gas were to be performed through the vent holes between, if flammable refrigerant is leaked, flammable cold
Since the medium enters the heater wire side through the ventilation hole,
Depending on the amount of flammable refrigerant enclosed in the refrigeration cycle,
If the number and size of pores are set appropriately, the flammability of leaked
Even if the refrigerant is ignited by the heater wire, the flame will vent
Safety is ensured because it cannot propagate through the holes.
In addition, the size of the passage can be changed depending on the number and size of ventilation holes.
It is easy to manufacture because it can be changed.

Next, in the invention described in claim 5, in the invention described in claim 4 , the area of the ventilation hole is 7.1 square millimeters.
Toru is obtained by the following, the variable that has leaked by this
Even if the flammable refrigerant is ignited by the heater wire, the flame
Safety is ensured because it cannot propagate through the vents
It Moreover, the water that enters the glass tube becomes steam.
When exhausted, it can be exhausted efficiently without creating resistance.

The invention according to claim 6 is the same as claim 1.
In the invention according to Item 2 or 2 , the positioning plate is provided with a vent hole.
Having a total length of at least 5 mm penetrating the positioning plate
It is equipped with an upper sleeve , which prevents leakage.
Even if the leaked flammable refrigerant is ignited by the heater wire,
The pores have a sleeve structure, and the creepage distance is long,
Safety because the flame cannot propagate through its vents
Is secured. Also, the sleeve is located inside the glass tube.
Since the positioning plate is easier to hold, the workability is improved.
To do.

[0015] Next the invention according to claim 7, claim 1 or
In the invention described in item 1 or 2 , the positioning plate is at least
It has a wire mesh structure of 20 mesh or more and can be placed in the heater wire.
The coiled portion covers the heater wire.
It is at least 20 mm away from the end face of the glass tube , and the flammable refrigerant that leaks is ignited by the heater wire.
Even if the flame is blocked by the wire mesh structure, the flame spreads.
do not do. Also, the water that enters the glass tube becomes steam.
Exhaust resistance when exhausted by
It is small and can be exhausted efficiently.

Next, the invention according to claim 8 is a flammable refrigerant.
The frost that adheres to and accumulates on the evaporator of the refrigeration cycle that contains
Equipped with a defrost heater that removes by heating,
Is a glass tube and a metal installed inside the glass tube.
A heater wire made of a resistor and a lead wire insertion hole are formed.
And a plug that covers the openings of both ends of the glass tube and the lead wire.
Leads connected to the end of the heater wire through the insertion hole
Line and the surface temperature of the glass tube emits flammable refrigerant.
The lead wire is adjusted so that the temperature is lower than the fire temperature.
It is formed by the difference between the insertion hole and the outer diameter of the lead wire.
The clearance is the inner space of the glass tube that has expanded due to temperature rise.
The gas between them is discharged to the outside, and the inside of the glass tube
Outside air around the defrost heater when decompressed due to lowering
Flow into the glass tube and allow
The glass tube when a flammable refrigerant flows in and the heater is energized
Prevents ignition and propagation to the outside of the glass tube even if it ignites inside
The glass tube has a cross-sectional area
Flows in and ignites in the glass tube when the heater is energized
Also, due to the clearance between the lead wire insertion hole and the lead wire,
Safety is ensured by preventing ignition and transmission to the outside.

Next, the invention according to claim 9 is a flammable refrigerant.
The frost that adheres to and accumulates on the evaporator of the refrigeration cycle that contains
Equipped with a defrost heater that removes by heating,
Is the first glass tube and the outer circumference of the first glass tube.
A second glass tube installed so as to cover the first glass and the first glass tube.
Heater wire made of metal resistor installed inside the lath tube
And a lead wire insertion hole is formed in front of the first glass tube.
A stopper for covering both end openings of the second glass tube, and the lead.
The lead connected through the wire insertion hole to the end of the heater wire.
The lead wire insertion hole and the outside of the lead wire.
The clearance formed by the difference between the diameter and
Flow the gas in the internal space of the stretched first glass tube to the outside.
And the inside of the first glass tube is reduced due to temperature decrease.
When pressurized, the outside air around the defrost heater is
Allow it to flow into the glass tube and into the first glass tube.
When the flammable refrigerant flows and the heater is energized, the first gas
Ignition outside the first glass tube even if ignition occurs inside the lath tube,
It has a cross-sectional area that prevents propagation ,
The double structure makes the surface temperature of the second glass tube flammable.
Keep the temperature below the ignition temperature of the volatile refrigerant, and place it in the first glass tube.
The first glass tube when combustible gas flows in and the heater is energized
Even if ignition occurs inside, the clearance between the lead wire insertion hole and the lead wire
Protects the first glass from ignition and propagation to the outside
Is secured.

The invention described in claim 10 is the same as claim 1.
In the invention described in any one of claims 9, Li
Formed by the difference between the lead wire insertion hole and the outer diameter of the lead wire
The cross-sectional area at any position in the clearance is 7.1 square millimeters.
It is less than or equal to Torr , and flammable gas is
Even if it flows in and ignites in the glass tube when the heater is energized,
Keep the cross-sectional area of the clearance of the wire insertion hole below a certain value.
Ensures safety by preventing ignition and propagation outside the glass
To be done.

Next, the invention according to claim 11 is the first aspect.
From the invention according to any one of claims 10 to
Lead wire positioned in the lead wire insertion hole, and the lead wire
And the total length of the connection that connects the heater wire with
Is 6 mm or more along the insertion hole , and the glass
When flammable gas flows into the tube and the heater is energized, the glass
Connection that connects the lead wire and heater wire even if ignition occurs in the pipe
By making the total length of the parts above a certain value, the glass
Safety is secured by preventing ignition and transmission to the outside .

The twelfth aspect of the invention is the flammable cold
Frost adhering to and accumulating on the evaporator of a refrigeration cycle with a medium
Equipped with a defrost heater that removes the
The first glass tube and the outside of the first glass tube.
The second glass tube installed so as to cover the circumference and the first glass tube
Heater wire made of metal resistor installed inside the glass tube
And opening both ends of the first glass tube and the second glass tube.
A stopper for covering the mouth, and an outer peripheral surface of the first glass tube
An empty space formed by the inner peripheral surface of the second glass tube and the stopper.
When the gas in the space expands due to temperature rise, the gas in the space
To the outside and the space is decompressed due to the temperature decrease.
When the outside air flows into the space when the
It is those provided in the first glass tube and second glass
Water in the refrigerator is stored in the space formed by the pipe and stopper.
The contained air flows in and evaporates due to the heat generated by the heater wire during defrosting.
If the pressure in the space rises, steam will pass through the passage.
Air is ejected, and the pressure increase in the space is alleviated.

Next, the invention according to claim 13 is the first aspect.
In the invention described in 2 , the cross-sectional area of the passage is 7.1 square meters.
It is below Remail and the leaked flammable refrigerant is
Empty formed by the first glass tube, the second glass tube and the stopper
Even if it enters the space and catches fire, the flame propagates through the passage.
It is not possible to secure the safety.

The invention according to claim 14 is the following :
The invention according to any one of 2, 9, 12, and 13
The inner surface of the stopper closely contacts the outer surface of the first glass tube
A cylindrical protrusion whose peripheral surface is in close contact with the inner peripheral surface of the second glass tube
Of the first glass tube and the second glass tube
One end can be closed with one stopper, reducing the number of parts
It

The invention described in claim 15 is the same as claim 1.
In the invention according to claim 2 or claim 13 , the stopper is the first
Inside the second glass tube and inside the glass tube
A cylindrical protrusion having an embedded outer periphery and a base of the cylindrical protrusion
And the outer circumference of the cylindrical protrusion
Has a groove that runs longitudinally from the root to the tip,
A gas passage is formed by the second glass tube and the groove.
The root of the cylindrical protrusion and the second glass tube
The end faces are those that are separated by a predetermined distance, the space
Moisture enters the space and evaporates due to the heat generated during defrosting, causing pressure inside the space.
If the force rises, steam will gush out of the groove and
The pressure rise in the space is reduced.

[0024] Next the invention according to claim 16, 請 Motomeko 1
In the invention according to 5, the circle is provided at the base of the cylindrical protrusion.
Project a certain distance from the base of the cylindrical projection toward the tip.
A convex portion for stopping the end face of the second glass tube at a predetermined position is provided , and the convex portion positions the second glass tube.
Becomes

Next, the invention according to claim 17 is the first aspect.
2 or the invention according to claim 13 , wherein the stopper is a cylinder
-Shaped projection and a plug body that holds the base of the cylindrical projection
The outer circumference of the cylindrical projection is two outer circumferences with different diameters.
The outer circumference of the root side is the first circumference and its diameter is
Set larger than the inner diameter of the second glass tube, and the outer circumference of the other
Is the second outer circumference and its diameter is the inner diameter of the second glass tube.
The same size is set, and the cylindrical protrusion has
Along the longitudinal direction from the root to the tip of the second outer periphery
A general groove is provided between the first outer circumference and the second outer circumference.
Due to the step portion formed, the end surface of the second glass tube is
It is stopped at a predetermined distance from the stopper body,
A gas passage is formed by the second glass tube and the groove , and when moisture enters the space and heat is generated during defrosting, steam is generated.
If the pressure in the space rises due to
The steam is jetted from the space, and the pressure increase in the space is reduced.

Next, the invention according to claim 18 relates to claim 1
In the invention according to claim 2 or claim 13 , the stopper is the first
Inside the second glass tube and inside the glass tube
A cylindrical protrusion having an embedded outer periphery and a base of the cylindrical protrusion
And the outer circumference of the cylindrical protrusion
Has a groove that runs longitudinally from the root to the tip,
A groove that intersects with the groove at the base of the cylindrical protrusion
Is provided, and the second glass tube and the groove are used to
It forms a passage , and when moisture enters the space and evaporates due to heat generation during defrosting and the pressure in the space rises, steam is jetted from the groove to increase the pressure in the space. Will be alleviated.

Next, the invention according to claim 19 is the first aspect.
In the invention described in any one of 2 , 13, 15 to 18, the outer entrance of the passage faces downward , and moisture enters the space and evaporates due to heat generated during defrosting. When the pressure in the space rises, steam is jetted from the passage , and the jetting direction is downward, so it is jetted.
No steam falls on the glass tube.

Next, the invention according to claim 20 is the first aspect.
In the invention according to claim 2 or claim 13 , the plug is a hole.
And the inner circumference into which the first glass tube enters and the second glass tube
A cylindrical protrusion having an outer circumference that goes inside, and the cylindrical protrusion
Along the inner circumference of the root, longitudinally cut from the root to the tip and
A groove for communication, the first glass tube, the groove and the
The holes form a gas passage , and when water enters the space and evaporates due to heat generated during defrosting and the pressure in the space rises , steam is passed through the groove and the hole. And the pressure rise in the space is alleviated.

Next, the invention of claim 21 is the same as claim 1
In the invention described in 2 or claim 13, plug, heating
Lead into which the lead wire connected to the end of the
The wire insertion hole, the inner circumference into which the first glass tube enters, and the second
A cylindrical protrusion having an outer circumference that enters the glass tube;
And a stopper main body for holding the base of the cylindrical projection,
A groove that runs longitudinally from the root to the tip on the inner circumference of the protrusion
And the lead wire that intersects the groove at the root of the inner circumference and
The groove connected to the lead wire insertion hole where
Providing the first glass tube, the groove, and the lead wire insertion
The hole forms a gas passage , and when moisture enters the space and evaporates due to heat generated during defrosting and the pressure in the space rises, the groove and the lead wire insertion hole are used. As a result, steam is ejected and the rise in pressure in the space is alleviated.

The invention according to claim 22 is the following:
In the invention described in any one of 2 , 9, 12 to 21, the total length of the first glass tube is the total length of the second glass tube.
Ri is obtained by a long, whereby the first glass tube
And first attach each end of the second glass tube to the stopper first
When attaching the other end to the other stopper
The end of the second glass tube projects from the end of the second glass tube
Since it can be inserted into the stopper while positioning sequentially, further work
Sexuality improves.

Next, the invention described in claim 23 is the invention described in any one of claims 1 , 2 , 8, 9 , and 12, wherein the water dripping from the evaporator is the glass of the defrost heater. An umbrella having a draining wall extending downward at the edge along the longitudinal direction is arranged vertically above the glass tube so as not to hit the tube surface, and the height of the draining wall is set to 0.5 mm or more and 5 mm or less. Since the air is retained between the umbrella and the glass tube, natural convection easily occurs, and the temperature of the surface of the glass tube can be suppressed below the ignition temperature of the flammable refrigerant.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a refrigerator according to the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a cross-sectional view of essential parts showing a defrosting heater for a refrigerator according to Embodiment 1 of the present invention, and FIG. 2 is a view for showing a defrosting heater for a refrigerator according to the same embodiment. It is a partial cross section perspective view.

In FIGS. 1 and 2, reference numeral 51 is a defrost heater for melting and removing frost attached to the evaporator 10 by heating, and 52 is a heater wire in which a resistance wire is formed in a coil shape. In the vicinity of both ends of 52, the heater wire 52 is not coiled but has a connecting end 52a which is folded and twisted in a predetermined length. 53 is the first covering the heater wire 52
Glass tube of 10.5 mm in outer diameter and 8.5 mm in inner diameter
It has a cylindrical shape and is open at both ends.

A second glass tube 54 covers the first glass tube 53 and has a cylindrical shape with an outer diameter of 20 mm and an inner diameter of 17 mm, and has both ends open. The total length of the first glass tube 53 is 17 mm longer than the total length of the second glass tube 54, and when arranged so that the midpoints of the respective lengths are aligned, the end surface of the first glass tube 53 is the second glass tube 54. From the end face of 8.
It is designed to project by 5 mm.

Reference numeral 55 is a lead wire connected to the heater wire 52, and 56 is a conductive connecting pipe connecting the heater wire 52 and the lead wire 55.

Reference numeral 57 is a disc-shaped positioning plate, which has a hole 57a into which the connecting pipe 56 is inserted, and three ventilation holes 57b (diameter 1.5 mm) are formed around the hole 57a.
It is provided with a center angle of 120 ° with respect to the center of 7a. The outer diameter of the positioning plate 57 is equal to or slightly smaller than the outer diameter of the first glass tube 53.

As a procedure for connecting the heater wire 52 and the lead wire 55, as a preliminary work, the heater wire 52 is inserted into the first glass tube 53, and the connecting tube 56 is further inserted into the hole 57a of the positioning plate 57. Inserting and positioning plate 57 is connecting pipe 5
Insert until it is located in the center of 6. Then, the end of the heater wire 52 is inserted from one open end of the connecting pipe 56, and the end of the lead wire 55 is inserted from the other open end of the connecting pipe 56 to prevent the positioning plate 57 from being deformed. Both ends of 56 are crimped with a jig. As a result, the ends of the heater wire 52 and the ends of the lead wire 55 are connected by the connecting pipe 56, and the positioning plate 57 is prevented from falling off due to the deformation of both ends of the connecting pipe 56.

Reference numeral 58 is a silicone rubber stopper that covers the open ends of the first glass tube 53 and the second glass tube 54. The lead wire insertion hole 58 into which the lead wire 55 is inserted in the stopper 58
a is provided, the workability is better if the lead wire 55 is inserted into the plug 58 before the end portion of the lead wire 55 is crimped by the connecting pipe 56. 58b is a positioning plate 5
It is a gap formed by 5 and the plug 58.

The stopper 58 has a cylindrical projection 59, the diameter of the inner periphery 59a of which is smaller than the outer diameter of the first glass tube 53 by about 1 mm, and the diameter of the outer periphery 59b thereof is the second glass tube 54.
Is formed to have the same size as the inner diameter of. For this reason, when the stopper 58 is fitted into the open ends of the first glass tube 53 and the second glass tube 54, the first glass tube 53 is pressed into the inner circumference 5 with a slight pressure.
9a, whereby the outer circumference 59b is slightly expanded, and the outer circumference 59b is pressed into the second glass tube 54.

The positioning plate 57 is sandwiched between the end surface of the first glass tube 53 and the inner wall 59c of the cylindrical projection 59, and the outer peripheral edge of the positioning plate 57 is in close contact with the inner circumference 59a of the cylindrical projection 59. Since the outer diameter of the positioning plate 57 is formed to be the same as or slightly smaller than the outer diameter of the first glass tube 53, the positioning plate 57 does not enter the inside of the first glass tube 53.

The lead wire insertion hole 58a of the plug 58 penetrates the inner wall 59c of the cylindrical projection 59, and the gas extends from the gap between the lead wire 55 and the lead wire insertion hole 58a to the inner wall 59c of the cylindrical projection 59. You can enter and exit.

The gas that has entered the inner wall 59c of the cylindrical protrusion 59 passes through the ventilation hole 57b of the positioning plate 57, enters the first glass tube 53, and touches the heater wire 52.

Further, the defrost heater 51 is a glass tube 53.
Lead wire insertion hole 58 formed in the plug covering the openings at both ends
and a, it is the following 7.1 mm2 cross-sectional area at any position of the gap portion formed by the difference between the outer diameter of the lead wire 55 passing through the insertion hole 58a.

Further, the defrosting heater 51 is a glass tube 53.
Lead wire insertion hole 58 formed in a plug covering both end openings
a, the lead wire 55 located in the insertion hole 58a, and
The total length of the connecting pipe (connecting portion) 56 connecting the lead wire 55 and the heater wire 52 is at least 6 mm or more and extends along the insertion hole 58a.

FIG. 3 is a schematic diagram of a refrigerator refrigeration system according to an embodiment of the present invention. In FIG. 3, reference numeral 60 is a compressor, 61 is a condenser, and 62 is a pressure reducing mechanism.
A flammable refrigerant is sealed inside the refrigeration cycle functionally connecting the condenser 61, the pressure reducing mechanism 62, and the evaporator 10.

The operation of the refrigerator using the defrosting heater constructed as described above will be described below. The evaporator 10 of the refrigeration cycle is cooled by the operation of the compressor 60, and the air inside the refrigerator passes through the cooled evaporator 10 by the fan 11 that operates simultaneously with the operation of the compressor 60.
Cold air that has exchanged heat with the evaporator 10 is discharged into the refrigerator. Then, after an arbitrary operating time of the compressor 60, the compressor 6
0 will also be shut down. At this time, at the same time, the heater wire 52 is energized through the lead wire 55 to heat the heater 52.

When the heater wire 52 generates heat, part of the radiant heat ray is directly transmitted to the outside, but the other part is transmitted to the first glass tube 53 and the second glass tube 54, and the second glass tube 5 is reached.
The surface of 4 rises to a temperature lower than the ignition temperature of the flammable refrigerant and radiates heat to the outside to defrost peripheral parts.

At this time, the gas expands in the internal space of the first glass tube 53 due to the temperature rise, and passes through the ventilation hole 57b of the positioning plate 57 and the gap between the lead wire 55 and the lead wire insertion hole 58a of the plug 58. It leaks to the outside.

When the heater wire 52 is de-energized and the cooling is started again in this state, the inside of the first glass tube 53 is decompressed due to the temperature drop, and the outside air around the defrost heater 51 is plugged with the lead wire 55 and the plug. 58 lead wire insertion hole 58a
Through the ventilation hole 57b of the positioning plate 57 into the inside of the first glass tube 53 through a gap between

In such a situation, in the unlikely event that the flammable refrigerant is present around the defrosting heater 51, the flammable refrigerant flows into the inner space of the first glass tube 53, and the heater wire at the start of defrosting starts. The heat generated by 52 increases the possibility that the flammable refrigerant will ignite.

However, even if the flammable refrigerant flowing into the inside of the first glass tube 53 is ignited, it is not unsafe unless the flame propagates through the ventilation hole 57b of the positioning plate 57. Therefore, in the present embodiment, the positioning plate 5
The area of the vent hole 57b of No. 7 is set to a size that the flame cannot propagate. Specifically, in an atmosphere of a flammable refrigerant of 3.0 volume percent, both ends of the first glass tube 53 are closed with plugs 58, and the positioning plates 57 at both ends of the first glass tube 53 are removed from the normal heater state. If the heater wire 52 is removed and opened (the opening area is approximately 57 mm 2) and 110 V is applied to both ends of the heater wire 52 to energize it, the surface temperature of the heater wire 52 reaches 590 ° C., but no unsafe condition occurs. Have confirmed.

Therefore, the ventilation hole 57 of the positioning plate 57
Even when the gas moves through b, the total area of the three ventilation holes 57b having a diameter of 1.5 mm is about 5.3 mm 2, and no explosion occurs. With this specification, it has been confirmed that no unsafety occurs even when 170 V is applied to both ends of the heater wire 52 to energize the heater wire 52 and the surface temperature of the heater wire 52 reaches 613 ° C.

Furthermore, it has been confirmed that no unsafety occurs even if the number of the ventilation holes 57b is set to one and the diameter thereof is increased to 3 mm (area: 7.1 square millimeter).

As a result, even if a flammable refrigerant is present around the defrosting heater 51, it is possible to prevent the explosion and fire due to the propagation of flame.

In this embodiment, the positioning plate 57 is used.
Although the vent hole 57b is provided in the above, the present invention is not limited to this. For example, the vent hole 57b is eliminated and the positioning plate 5 is removed.
It is also possible to provide a gap between the outer peripheral edge of 7 and the inner periphery 59a of the cylindrical protrusion 59 to substitute for the vent hole 57b.

Further, in the present embodiment, the cylindrical projection 59
Although the outer circumference of is circular, it may be wavy as shown in FIG. 4, for example. In FIG. 4, 63 is a plug having the same function as the plug 58, 64 is a cylindrical protrusion provided on the plug 63, and an inner circumference 64a is press-fitted to the outer circumference of the first glass tube 53, The outer circumference 64b is also the second glass tube 54.
It is loosely attached to the inner circumference of. At this time, since the outer periphery 64b is formed in a wavy shape, the compressed crests 64c move to the troughs 64d to fit in, so that the assembling becomes easy and the workability also improves.

Furthermore, even if a gap is formed between the valley 64d and the inner circumference of the second glass tube 54 after the peak 64c of the outer circumference 64b is pressed and moves to the valley 64d, the size of the clearance is flammable. If the size of the flame that cannot be propagated is set in advance in accordance with the amount of the heat-resistant refrigerant enclosed, even if the heater wire 52 is energized for defrosting in an atmosphere in which the flammable refrigerant leaks, the valleys of the outer circumference 64b are reduced. The inflammable refrigerant that has entered through the gap between 64d and the inner circumference of the second glass tube 54 cannot ignite and propagate the flame to the outside, so that no insecurity occurs.

Further, an arbitrary position of a clearance portion formed by the difference between the lead wire insertion hole 58a formed in the stopper 58 covering the openings at both ends of the glass tube 53 and the outer diameter of the lead wire 55 passing through the insertion hole 58a. Is a defrost heater 51 having a cross-sectional area of 7.1 square millimeters or less, and even if a combustible gas flows into the glass tube 53 and the heater ignites inside the glass tube 53. By setting the cross-sectional area of the clearance of the lead wire insertion hole 58a to a certain value or less, the glass tube 53
Highly safe defrost heater 5 that prevents ignition and propagation to the outside
It can be 1.

Further, a lead wire insertion hole 58a formed in the stopper 58 covering the openings at both ends of the glass tube 53, a lead wire 55 located in the insertion hole 58a, and a connecting pipe connecting the lead wire 55 and the heater wire 52. The defrost heater 51 is characterized in that the total length of the (connecting portion) 56 is at least 6 mm or more and is along the insertion hole 58a, and a combustible gas flows into the glass tube 53 to energize the heater. Even if the glass tube 53 ignites, the lead wire 55 and the heater wire 5
By setting the total length of the connecting portions 56 that connect the two to a certain value or more, it is possible to provide the defrost heater 51 with high safety by preventing ignition and propagation to the outside of the glass 53.

In this embodiment, the positioning plate 57 is used.
Although the structure has the ventilation hole 57b, it may be provided with a sleeve having a ventilation hole as shown in FIG. 5, for example. In FIG. 5, reference numeral 70 denotes a positioning plate having the same function as the positioning plate 57, 71 denotes a sleeve provided on the positioning plate 70, which penetrates the positioning plate 70 and has ventilation holes 71a at both ends thereof. . By appropriately setting the sleeve position, the sleeve is attached to the inner circumference of the first glass tube 53 with a slight contact, and the positioning plate 70 is easily held, and the workability is improved.

Further, even if the leaked flammable refrigerant is ignited by the heater wire 52, the ventilation hole has a sleeve 71 structure and the creeping distance is long, and the flame has the ventilation hole 71.
Since a cannot be propagated, insecurity does not occur.
By adjusting the sleeve length and hole diameter, it is possible to easily change the characteristics for flame propagation.

In this embodiment, the one-piece positioning plate 57 has the ventilation hole 57b, but it may have a wire mesh structure as shown in FIG. 6, for example. In FIG. 6, reference numeral 80 is a positioning plate that performs the same function as the positioning plate 57, and is at least 20 in order to prevent flame propagation.
It is made of wire mesh that is larger than the mesh. Connection pipe 8 in the center
There is a hole 82 into which 1 is inserted, and the outer diameter of the positioning plate 80 is formed to be the same as or slightly smaller than the outer diameter of the first glass tube 53. 53a is one end face of the first glass tube 53. Reference numeral 52 denotes a heater wire in which a resistance wire is formed in a coil shape. The vicinity of both ends of the heater wire 52 is not coiled but has a connection end 52a in which the heater wire 52 is folded back and twisted in a predetermined length. Reference numeral 53 is a first glass tube that covers the heater wire 52, has a cylindrical shape with an outer diameter of 10.5 mm and an inner diameter of 8.5 mm, and has both ends open. The glass tube end face 53a and the coil-shaped heater wire 52 secure a distance of at least 20 mm or more via the connection end 52a. As a result, the positioning plate 80 can be separated from the heater wire 52 serving as a heat source, and the positioning plate 8
By forming 0 with a wire mesh of at least 20 mesh or more, even if the heater wire 52 is energized for defrosting in an atmosphere where the flammable refrigerant leaks, the flammable refrigerant that has entered will ignite to the outside. There is no insecurity because it cannot be propagated.

Further, at least 20 positioning plates 80 are provided.
Since it has a wire mesh structure of mesh or more, the glass tube 53
The exhaust resistance when the moisture that has entered the inside becomes vapor and is exhausted is smaller than that when the vent hole is provided, and the exhaust can be performed efficiently, so that the rust of the heater wire 52 due to the retention of the moisture can be prevented.

In this embodiment, the cylindrical protrusion 59
Although the outer circumference of is circular, it may have a groove as shown in FIG. 7, for example. In FIG. 7, 90 is a stopper that performs the same function as the stopper 58, 91 is a cylindrical protrusion provided on the stopper 90, and the inner periphery 91a is press-fitted to the outer periphery of the first glass tube 53, The outer circumference 91b is also the second glass tube 5
It is attached to the inner circumference of 4 with a slight press fit. At this time, the outer circumference 91b
Since the groove 92 is formed in the groove, the flexibility is increased, the assembling is facilitated, and the workability is also improved.

Furthermore, since the cross-sectional area of the groove 92 is 7.1 square millimeters or less, even if a gap corresponding to the cross-sectional area is formed between the groove 92 and the inner circumference of the second glass tube 54, Even if the heater wire 52 is energized for defrosting in an atmosphere in which the flammable refrigerant has leaked, the flammable refrigerant that has entered cannot ignite and propagate the flame to the outside. There is no.

In this embodiment, the defrost heater 5
The glass tube covering the first heater wire 52 has a double structure including a first glass tube 53 and a second glass tube 54.
A single glass tube may be used, and the resistance value of the heater wire 52 and the watt density per unit may be adjusted so that the surface temperature of the glass tube becomes lower than the ignition point temperature of the flammable refrigerant.
In the case of a single glass tube, the cost can be kept low as compared with the double structure.

(Embodiment 2) FIG. 8 is a cross-sectional view of essential parts of a defrosting heater for a refrigerator according to Embodiment 2 of the present invention. The same components as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

In FIG. 8, reference numeral 100 denotes a stopper having the same function as that of the stopper 58 of the first embodiment, which is composed of a stopper main body 101 and a cylindrical protrusion 102 provided on the stopper main body 101, and an inner circumference of the cylindrical protrusion 102. 102a is attached to the outer periphery of the first glass tube 53 with a slight pressure, and outer periphery 102b is also attached to the inner periphery of the second glass tube 54 with a slight pressure.

Reference numeral 103 is a passage that penetrates the cylindrical projection 102 in the longitudinal direction and passes through the plug body 101. 104 is a space formed by the first glass tube 53, the second glass tube 54, and the stopper 100.

The operation of the refrigerator using the defrosting heater constructed as described above will be described below. The evaporator 10 of the refrigeration cycle is cooled by the operation of the compressor 60, and the air inside the refrigerator passes through the cooled evaporator 10 by the fan 11 that operates simultaneously with the operation of the compressor 60.
Cold air that has exchanged heat with the evaporator 10 is discharged into the refrigerator. Then, after an arbitrary operating time of the compressor 60, the compressor 6
0 will also be shut down. At this time, at the same time, the heater wire 52 is energized through the lead wire 55 to heat the heater wire 52.

When the heater wire 52 generates heat, part of the radiant heat ray is directly transmitted to the outside, but the other part is transmitted to the first glass tube 53 and the second glass tube 54, and the second glass tube 5 is transmitted.
The surface of 4 rises to a temperature lower than the ignition temperature of the flammable refrigerant and radiates heat to the outside to defrost peripheral parts.

At this time, in the space 104 formed by the first glass tube 53, the second glass tube 54 and the stopper 100,
The gas expands due to the temperature rise and flows out from the passage 103 to the outside.

Then, when the energization of the heater wire 52 is stopped and the cooling is started again in this state, the space 104 is decompressed due to the temperature decrease, and the outside air containing moisture flows into the space 104 from the passage 103.

When the heater wire 52 is again energized to generate heat in the heater wire 52, the temperature inside the space 104 evaporates due to the temperature rise, and the pressure inside the space 104 starts to rise due to the water vapor. However, since a part of the water vapor flows out from the passage 103, the pressure increase in the space 104 is moderated.

By the above operation, the first glass tube 53
The second glass tube 54 is safe because it can be prevented from being destroyed by the pressure increase due to the evaporation of water.

Furthermore, when the flammable refrigerant leaks into the refrigerator and the flammable refrigerant flows into the space 104, the flow passage cross-sectional area through which the flammable refrigerant flows is as described in the first embodiment. If it is 1 mm 2 or less, even if the flammable refrigerant is ignited, flame propagation does not occur and no explosion occurs. Therefore, the maximum cross-sectional area of the passage 103 is set to 7.1 mm 2 or less to prevent explosion.

Further, in this embodiment, the passage 103 has a perfect tubular shape, but it may have a groove shape as shown in FIG. In FIG. 9, reference numeral 200 denotes a stopper having the same function as that of the stopper 100, which is composed of a stopper body 201 and a cylindrical protrusion 202, and an inner periphery 202a of the cylindrical protrusion 202 is press-fitted to the outer periphery of the first glass tube 53. And the outer circumference 202b is also the second
It is attached to the inner circumference of the glass tube 54 with a slight pressure. The end surface of the second glass tube 54 stops at a position separated from the stopper body 201 by about 1 mm.

On the outer circumference 202b of the cylindrical projection 202, there is provided a groove 203 extending longitudinally from the root to the tip, and the passage 2 is formed by the second glass tube 54 and the groove 203.
04 is formed.

Further, positioning as shown in FIGS. 10 and 11 may be provided so that the end surface of the second glass tube 54 stops at a predetermined position.

In FIG. 10, reference numeral 300 denotes a stopper having the same function as that of the stopper 100. The stopper main body 301 and the cylindrical projection 30 are provided.
2, the inner circumference 302a of the cylindrical projection 302 is fitted into the outer circumference of the first glass tube 53 with a slight pressure, and the outer circumference 302a.
b is also fitted into the inner circumference of the second glass tube 54 with a slight pressure.

A convex portion 302c is formed at the base of the cylindrical protrusion 302.
And the convex portions 302c are arranged at 90 ° intervals around the central axis of the cylindrical protrusion 302.
1 mm in the longitudinal direction from the root of. Since the end surface of the second glass tube 54 is positioned by the convex portion 302c,
The end surface of the second glass tube 54 will stop at a position about 1 mm away from the stopper body 301.

On the outer circumference 302b of the cylindrical projection 302, there is provided a groove 303 traversing in the longitudinal direction from the root to the tip, and the passage 3 is formed by the second glass tube 54 and the groove 303.
04 is formed.

In FIG. 11, reference numeral 400 denotes a stopper having the same function as that of the stopper 100. The stopper main body 401 and the cylindrical projection 40 are provided.
2, the inner circumference 402a of the cylindrical projection 402 is fitted into the outer circumference of the first glass tube 53 with a slight pressure, and the outer circumference 402a.
b (second outer periphery) is also fitted into the inner periphery of the second glass tube 54 with a slight pressure.

1 from the root of the cylindrical protrusion 402 in the longitudinal direction.
The range of mm is formed by the outer circumference 402c (first outer circumference) having a diameter larger than the inner diameter of the second glass tube 54, and the end surface of the second glass tube 54 has the second outer circumference 402b and the first outer circumference 402.
Since the positioning is performed by the step formed between the second glass tube 54 and c, the end surface of the second glass tube 54 stops at a position about 1 mm away from the plug body 401.

Grooves 403 are provided on the second outer circumference 402b and the first outer circumference 402c of the cylindrical projection 402 to extend longitudinally from the root to the tip, and the passage 404 is formed by the second glass tube 54 and the groove 403. It is formed.

Further, as shown in FIG. 12, a groove may be provided in the plug body. In FIG. 12, reference numeral 500 denotes a stopper that performs the same function as the stopper 100, and includes a stopper body 501 and a cylindrical protrusion 50.
2, the inner circumference 502a of the cylindrical projection 502 is fitted into the outer circumference of the first glass tube 53 with a slight pressure, and the outer circumference 502a.
b is also fitted into the inner circumference of the second glass tube 54 with a slight pressure.

The outer periphery 502b of the cylindrical protrusion 502 is provided with a groove 503 longitudinally extending from the root to the tip, and the plug body 501 is provided with a groove 504 intersecting the groove 503 and vertically extending vertically. The second glass tube 54, the groove 503, and the groove 504 form a passage 505.
Is formed.

As described above, by forming a groove in the stopper,
In the space 104 formed by the first glass tube 53, the second glass tube 54, and the stopper, even if the gas in the space 104 expands and the pressure rises due to the heat generation of the heater wire 52, the gas flows through the groove. Since the pressure rises in the space 104 is mitigated because the gas flows out, the first glass tube 53 and the second glass tube 5
4 can be prevented from bursting.

Further, as shown in FIG. 13, a groove may be provided on the inner circumference of the cylindrical protrusion. In FIG. 13, reference numeral 600 denotes the stopper 1.
A plug having the same function as that of 00, including a plug body 601 and a cylindrical protrusion 602, and an inner circumference 602 of the cylindrical protrusion 602.
a is attached to the outer periphery of the first glass tube 53 with a slight pressure,
The outer circumference 602b is also fitted into the inner circumference of the second glass tube 54 with a slight pressure.

On the inner circumference 602a of the cylindrical protrusion 602, a groove 603 is provided which is longitudinally cut from the root to the tip, and the groove 603 communicates with the lead wire insertion hole 601a and is connected to the first glass tube 54. A passage 604 is formed by the lead wire insertion hole 601a and the groove 603. A plurality of grooves 603 may be provided on the inner circumference 602a.

As a result, the gas in the space 104 can be moved through the lead wire insertion hole 601a and the passage 604, and the gas inlet of the passage 604 is located at the stopper main body 6.
01 It does not appear in the appearance, so it is preferable in terms of design.

As described above, by forming a groove in the stopper,
In the space 104 formed by the first glass tube 53, the second glass tube 54, and the stopper, even if the gas in the space 104 expands and the pressure rises due to the heat generation of the heater wire 52, the gas flows through the groove. Since the pressure rises in the space 104 is mitigated because the gas flows out, the first glass tube 53 and the second glass tube 5
Since the rupture of No. 4 does not occur and the surfaces of the heater wire 52 and the surface of the first glass tube 53 are not exposed to the outside air, even if the flammable refrigerant leaks in the refrigeration cycle in which the flammable refrigerant is sealed, an explosion occurs. This kind of flame is safe and safe.

(Embodiment 3) FIG. 14 is a cross-sectional view of essential parts of a defrosting heater for a refrigerator according to Embodiment 3 of the present invention, and FIG. 15 is a cross-sectional view of a defrosting heater for a refrigerator according to the same embodiment. FIG. The same components as those in the second embodiment will be assigned the same reference numerals and detailed description thereof will be omitted.

In FIGS. 14 and 15, reference numeral 700 denotes a stopper having the same function as that of the stopper 100 of the second embodiment, which is composed of a stopper main body 701 and a cylindrical projection 702 provided on the stopper main body 701.

Reference numeral 703 is a passage which penetrates the cylindrical projection 702 in the longitudinal direction and passes through the plug body 701. 104 is a space formed by the first glass tube 53, the second glass tube 54, and the stopper 700.

Reference numeral 705 denotes an umbrella which is positioned vertically above the second glass tube 54 and is held by the stopper body 701 of the stopper 700. Water droplets falling from the evaporator are prevented from falling in the second glass tube 54.
I try not to hit the surface of directly.

In the vicinity of both end portions 705a of the umbrella 705, a holding portion 705b formed in a convex shape having a width narrower than other regions.
Is provided. The holding portion 705b is inserted into a holding hole 704 provided in the upper portion of the plug body 701.

A draining wall 705c is provided along the longitudinal direction at the edge of the umbrella 705 so that the water falling from the evaporator does not flow into the inside of the umbrella 705.

The height H of the draining wall 705c of the umbrella 705 is
When the size is increased, the gas is likely to stay between the umbrella 705 and the second glass tube 54, and the surface temperature of the second glass tube 54 is increased by the temperature rise of the staying gas when the heater wire 52 generates heat.

Particularly, in a refrigeration cycle in which a flammable refrigerant is sealed, the surface temperature of the second glass tube 54 is set to be lower than the ignition temperature of the flammable refrigerant in order to ensure safety even if the flammable refrigerant leaks. It is desirable to set to. Therefore, the height H of the draining wall 705c should be made as small as possible so that the gas between the umbrella 705 and the second glass tube 54 is unlikely to stay. In this embodiment, the draining wall 705
The height H of c is set to 0.5 mm or more and 5 mm or less to suppress the retention of gas and prevent an excessive temperature rise on the surface of the second glass tube 54.

As described above, the height of the draining wall 705c of the umbrella 705 provided vertically above the second glass tube 54 is set according to the refrigerant enclosed in the refrigeration cycle, so that the second glass tube 54 The temperature rise on the surface can be controlled, and especially when a flammable refrigerant is sealed, if the height of the draining wall 705c is set to 0.5 mm or more and 5 mm or less, the second glass tube 54 and the umbrella 705 Since the gas is unlikely to stay in the space, it is possible to suppress an excessive temperature rise on the surface of the second glass tube 54.

Since the surplus temperature rise of the surface temperature of the second glass tube 54 is suppressed, the surplus temperature rise of the inside of the chamber at the time of defrosting can also be suppressed, so that the cooling after the completion of defrosting is efficient. It is often done to save energy.

Further, in each of the above-described embodiments, the refrigerator has been described as an example of the device to which the defrost heater is applied, but the invention is not limited to this, and a so-called cooling storage equipped with an evaporator may be used. For example, it can be widely applied to a showcase or a vending machine provided with a refrigeration cycle in which a flammable refrigerant is sealed.

[0105]

As described above, the invention according to claim 1 is provided with a defrost heater for removing frost adhered and accumulated on the evaporator of the refrigeration cycle enclosing a combustible refrigerant by heating, frost heater, the heater wire made of the glass tube and the metal resistor installed inside said glass tube, Lee
A plug for forming a wire insertion hole and covering both end openings of the glass tube, and an end of the heater wire passing through the lead wire insertion hole
Lead wire connected to the heater wire and the lead wire
The connection is provided at the connection with the wire and is held by the stopper.
And a positioning plate for preventing the portion from moving, the surface temperature of the glass tube is adjusted to be lower than the ignition temperature of the flammable refrigerant, and is formed by the stopper and the positioning plate.
The size of the gap that is set between the flammable refrigerant and the plug
Through the gap formed with the deciding plate to the heater wire side
Even if it enters and ignites, it is formed by the stopper and the positioning plate.
The size of the gap is set so that the flame does not propagate , and the flammable refrigerant that leaks into the cabinet is formed by the stopper and the positioning plate.
Even if it enters the glass tube through the gap formed and ignites due to the heat generated by the heater wire, the flame is formed by the plug and the positioning plate.
Since it does not propagate through the gap , the explosion does not occur and safety is secured.

Further, the invention according to claim 2 is provided with a defrosting heater for removing frost adhered and accumulated on the evaporator of the refrigeration cycle enclosing a combustible refrigerant by heating, and the defrosting heater is the first defrosting heater. Glass tube, a second glass tube installed so as to cover the outer periphery of the first glass tube, a heater wire made of a metal resistor installed inside the first glass tube, and a lead wire insertion hole. A plug formed to cover the openings at both ends of the first glass tube and the second glass tube; and the lead.
The lead connected through the wire insertion hole to the end of the heater wire.
Lead wire and the connection between the heater wire and the lead wire.
And is held by the stopper to prevent the connection part from moving.
And a positioning plate for preventing the stopper and the positioning plate.
The size of the gap formed by the flammable refrigerant and the plug
The heater passes through a gap formed with the positioning plate.
-Even if it enters the line side and ignites, the plug and the positioning plate
The size of the gap formed by <3> is set so that flame does not propagate , and by making the glass tube a double structure, the surface temperature of the second glass tube is kept below the ignition temperature of the flammable refrigerant. The flammable refrigerant that has been maintained and leaked into the refrigerator is formed by the stopper and positioning plate.
Even if it enters the first glass tube through the gap formed and ignites due to the heat generated by the heater wire, the flame is formed by the plug and the positioning plate.
Since it does not propagate through the created gap , explosion does not occur and safety is secured.

The invention described in claim 3 is the same as claim 1
Or in the invention described in 2, viewed from the glass tube end face side
The gap formed between the stopper and the positioning plate at an arbitrary position.
It is intended that the area was less than 57 mm2, this
The flammable refrigerant leaked by this is generated by the heater wire.
Even if fired, the flame formed in the gap between the stopper and the positioning plate
Since it cannot be propagated, no explosion will occur and safety is assured.
Retained.

The invention described in claim 4 is the same as claim 1
Or in the invention described in 2 , the positioning plate is provided with a vent hole.
The inner edge of the positioning plate is closely attached to the inside of the stopper,
Der which the movement of the gas was <br/> to be performed through the vent holes in Sotoma is, if the flammable refrigerant is leaked, flammable
Refrigerant enters the heater wire side through its vent
Therefore, depending on the amount of flammable refrigerant enclosed in the refrigeration cycle,
If the number and size of the ventilation holes are set appropriately, leakage
Even if flammable refrigerant is ignited by the heater wire, the flame
Safety is ensured because it cannot propagate through the vents of
Be done. Moreover, the size of the passage depends on the number and size of the ventilation holes.
Because the height can be changed, it is easy to manufacture.

The invention described in claim 5 is the same as claim 4
In the invention described in, the area of the ventilation hole is 7.1 square millimeters.
It was made less than a meter and was leaked by this
Even if flammable refrigerant is ignited by the heater wire, the flame
Because it can not propagate through the vents of the
Safety is secured. Moreover, water that has entered the glass tube
When the minute becomes vapor, it is efficient without exhausting resistance
It can be exhausted easily.

The invention described in claim 6 is the same as claim 1
Or in the invention described in 2 , the positioning plate has a ventilation hole.
Has a total length of at least 5 mm that penetrates the positioning plate.
With the above sleeve ,
Even if the leaked flammable refrigerant is ignited by the heater wire,
The ventilation hole has a sleeve structure to keep the creepage distance long.
The flame is not able to propagate through its vents and is therefore safe.
Integrity is secured. Also, the sleeve is placed inside the glass tube.
Since it is installed, it will be easier to hold the positioning plate and workability will be improved.
improves.

The invention described in claim 7 is the same as claim 1
Or in the invention described in 2 , the positioning plate is at least
Also has a wire mesh structure of 20 mesh or more,
The coiled part covers the heater wire.
It is at least 20 mm or more away from the end face of the glass tube , and the leaked flammable refrigerant is generated by the heater wire.
Even if fired, the flame was blocked by the wire mesh structure,
Do not sow. Also, the water that enters the glass tube will not turn into steam.
Exhaust resistance when exhausted is better than when ventilation holes are provided.
Is small and can exhaust efficiently.

The invention described in claim 8 is a flammable cooling system.
Frost adhering to and accumulating on the evaporator of a refrigeration cycle with a medium
Equipped with a defrost heater that removes the
The glass tube and the metal installed inside the glass tube
A heater wire made of a metal resistor and a lead wire insertion hole are formed.
And a plug that covers the openings at both ends of the glass tube and the lead.
The lead connected through the wire insertion hole to the end of the heater wire.
And the surface temperature of the glass tube is a flammable refrigerant.
The lead is adjusted so that it is below the ignition temperature.
Formed by the difference between the wire insertion hole and the outer diameter of the lead wire
The clearance is the inside of the glass tube expanded by the temperature rise
The gas in the space is discharged to the outside, and the inside of the glass tube is warmed.
Outside the area around the defrost heater
Let air flow into the glass tube,
When the combustible refrigerant flows in and the heater is energized, the glass
Prevents ignition and propagation outside the glass tube even if it ignites inside the tube
It is those having a cross-sectional area, combustible gas in the glass tube
Gas flows in and ignites in the glass tube when the heater is energized.
Also, due to the clearance between the lead wire insertion hole and the lead wire,
Safety is ensured by preventing ignition and transmission to the outside.

The invention described in claim 9 is a flammable cooling system.
Frost adhering to and accumulating on the evaporator of a refrigeration cycle with a medium
Equipped with a defrost heater that removes the
The first glass tube and the outside of the first glass tube.
The second glass tube installed so as to cover the circumference and the first glass tube
Heater wire made of metal resistor installed inside the glass tube
And a lead wire insertion hole is formed in front of the first glass tube.
A stopper for covering both end openings of the second glass tube, and the lead.
The lead connected through the wire insertion hole to the end of the heater wire.
The lead wire insertion hole and the outside of the lead wire.
The clearance formed by the difference between the diameter and
Flow the gas in the internal space of the stretched first glass tube to the outside.
And the inside of the first glass tube is reduced due to temperature decrease.
When pressurized, the outside air around the defrost heater is
Allow it to flow into the glass tube and into the first glass tube.
When the flammable refrigerant flows and the heater is energized, the first gas
Ignition outside the first glass tube even if ignition occurs inside the lath tube,
It has a cross-sectional area that prevents propagation ,
The double structure makes the surface temperature of the second glass tube flammable.
Keep the temperature below the ignition temperature of the volatile refrigerant, and place it in the first glass tube.
The first glass tube when combustible gas flows in and the heater is energized
Even if ignition occurs inside, the clearance between the lead wire insertion hole and the lead wire
Protects the first glass from ignition and propagation to the outside
Is secured.

The invention described in claim 10 is the invention described in any one of claims 1 to 9 ,
It is formed by the difference between the lead wire insertion hole and the outer diameter of the lead wire.
The cross-sectional area at any position of the clearance is 7.1 square mm.
The glass tube is flammable gas.
Flows in and ignites in the glass tube when the heater is energized
Keep the cross-sectional area of the lead wire insertion hole clearance below a certain value.
Protects against ignition and transmission to the outside of the glass to ensure safety.
Retained.

The invention according to claim 11 is the same as the invention according to any one of claims 1 to 10 , wherein the lead wire located in the lead wire insertion hole and the lead wire are provided.
The total length of the connection part that connects the
Kutomo 6mm above, which are along the insertion hole, moth
When flammable gas flows into the lath tube and the heater is energized,
Connect the lead wire and heater wire even if ignition occurs in the lath tube
By setting the total length of the connection to a certain value or more,
Safety is secured by preventing ignition and propagation outside the lath.

Further, the invention according to claim 12 is combustible
Adhered to and accumulated on the evaporator of the refrigeration cycle containing the refrigerant
Equipped with a defrost heater that removes frost by heating,
The heater includes a first glass tube and the first glass tube.
The second glass tube installed so as to cover the outer periphery, and the first glass tube
Heater made of metal resistor installed inside the glass tube of
Wire and both ends of the first glass tube and the second glass tube
An outer peripheral surface of the first glass tube, comprising: a stopper covering an opening.
And the inner peripheral surface of the second glass tube and the stopper.
When the gas in the space expands due to the temperature rise, the gas in the space
Let the body flow out and the space will be decompressed due to the temperature drop.
The passage that allows outside air to flow into the space when
The first glass tube and the second glass provided on the stopper.
In the space formed by the lath tube and the stopper, the water in the refrigerator
Air flows containing evaporation heating arsenide Ta line at the time of defrosting
However, if the pressure in the space rises,
Since the steam is ejected and the pressure rise in the space is alleviated,
Safer because the glass tube does not burst under the pressure of steam
Will be more likely.

The invention according to claim 13 is the following:
In the invention described in 12 , the passage has a cross-sectional area of 7.1 square.
Leakage flammable refrigerant that is less than millimail
Is formed of a first glass tube, a second glass tube and a stopper
Even if it enters the space and catches fire, the flame may propagate through the passage.
The safety is ensured because it cannot be done.

The invention according to claim 14 is the following :
The invention according to any one of 2, 9, 12, and 13
The inner surface of the stopper closely contacts the outer surface of the first glass tube
A cylindrical protrusion whose peripheral surface is in close contact with the inner peripheral surface of the second glass tube
Of the first glass tube and the second glass tube
One end can be closed with one stopper, reducing the number of parts
It

The invention according to claim 15 is the following:
In the invention of claim 12 or claim 13 , the stopper is the first
Enter the inner circumference of the first glass tube and the second glass tube.
Cylindrical protrusion consisting of the outer periphery to be embedded and the root of the cylindrical protrusion
It is composed of a stopper body that holds the original, and the outside of the cylindrical protrusion.
A groove is provided on the circumference that extends vertically from the root to the tip,
A gas passage is formed by the second glass tube and the groove.
So that the root of the cylindrical protrusion and the second glass tube
The end face of are those that are separated by a predetermined distance, the air
Water enters the space and evaporates due to heat generated during defrosting
When the pressure rises, steam is ejected from the groove and
Since the pressure rise in the space is alleviated, the glass tube
It is not damaged by pressure and is more safe.

Furthermore, the gas passage has a simple shape called a groove.
Since it can be configured, the plug can be easily processed and the cost can be reduced.
It

The invention according to claim 16 is the following:
In the invention as set forth in claim 15, at the base of the cylindrical protrusion,
Projected a certain distance from the base of the cylindrical protrusion toward the tip
Provide a convex part that stops the end surface of the second glass tube at a predetermined position.
And the convex portion is positioned on the second glass tube.
As a result, workability is improved when the glass tube is attached.

The invention according to claim 17 is the following:
In the invention according to claim 12 or claim 13 , the stopper is a circle.
A cylindrical projection and a plug body that holds the root of the cylindrical projection
The outer circumference of the cylindrical protrusion is two outer parts with different diameters.
It consists of a peripheral surface, and the outer circumference on the root side is the first outer circumference and its diameter
Is set larger than the inner diameter of the second glass tube, and the outside of the other
The circumference is defined as the second outer circumference, and the diameter is defined as the inner diameter of the second glass tube.
Set to the same size as, and the cylindrical protrusion has the first outer periphery.
Longitudinally from the root to the tip of the second outer periphery
A common groove is provided between the first outer circumference and the second outer circumference.
Due to the step formed, the end face of the second glass tube is moved forward.
It is stopped at a position that is a predetermined distance away from the stopper body,
Note that the second glass tube and the groove form a gas passage , and moisture enters the space to generate heat during defrosting.
If the pressure in the space evaporates and rises, the passage
The steam erupts from the
The glass tube is not damaged by the pressure of steam,
Higher safety.

Furthermore, the gas passage has a simple shape called a groove.
Can be processed easily, and the glass tube
At the time of wearing, the two outer stepped parts do not position the glass tube.
Therefore, the workability is improved and the cost can be reduced.

Further, the invention according to claim 18 is the following:
In the invention of claim 12 or claim 13, the stopper is the first
Enter the inner circumference of the first glass tube and the second glass tube.
Cylindrical protrusion consisting of the outer periphery to be embedded and the root of the cylindrical protrusion
It is composed of a stopper body that holds the original, and the outside of the cylindrical protrusion.
A groove is provided on the circumference that extends vertically from the root to the tip,
The plug body intersects with the groove at the base of the cylindrical protrusion.
A groove is provided, and gas is generated by the second glass tube and the groove.
It forms the passage of water, and moisture enters the space.
However, if the pressure in the space rises due to evaporation due to the heat generated during defrosting,
In this case, steam is ejected from the groove and the pressure in the space rises.
Because There is relaxed, child broken glass tube with pressure steam
It is safer and more secure.

Further, the invention according to claim 19 is the following:
In the invention described in any one of 12, 13, 15 to 18, the outside entrance of the passage faces downward , and moisture enters the space and evaporates due to heat generated during defrosting. When the pressure in the space rises, steam spouts from the passage , and the spouting direction is downwards.
Steam does not fall on the glass tube and
It is possible to suppress an unpleasant sound that is generated when the vehicle is falling.

Further, the invention according to claim 20 is the following:
In the invention of claim 12 or claim 13, the plug is a hole.
And the inner circumference into which the first glass tube enters and the second glass tube
A cylindrical protrusion having an outer circumference that goes inside, and the cylindrical protrusion
Along the inner circumference of the root, longitudinally cut from the root to the tip and
A groove for communication, the first glass tube, the groove and the
The holes form a gas passage, and
Water enters and evaporates due to heat generated during defrosting, and the pressure in the space
If rising, steam will be ejected through the groove and hole.
Since the pressure rise in the space is alleviated, the glass tube
It is not damaged by steam pressure and is more safe.
It

Furthermore, the gas passage has a simple shape called a groove.
Can be processed easily, and the glass tube
At the time of wearing, the base of the cylindrical protrusion becomes the positioning of the glass tube,
Workability is improved and cost can be reduced.

The invention according to claim 21 is the claim
In the invention of claim 12 or claim 13 , the stopper is a heat sink.
Lead into which the lead wire connected to the end of the heater wire is inserted.
Second wire insertion hole, the inner circumference into which the first glass tube enters, and the second
And a cylindrical protrusion consisting of an outer periphery that enters the glass tube of
And a stopper body that holds the root of the cylindrical protrusion,
Along the inner circumference of the cylindrical protrusion, make a longitudinal cut from the root to the tip.
The groove intersects the groove at the root of the inner circumference and the lead
A groove connected to the lead wire insertion hole in which the wire is inserted,
The first glass tube, the groove and the lead wire insertion
Entry apertures are those which form a passing path of gas, wherein when the pressure of the water is evaporated by heat generated when entering and defrosting the space rises to the space, the groove and the lead wire insertion hole Since the steam is jetted out through the pipe and the pressure rise in the space is moderated, the glass tube is not damaged by the pressure of the steam, and the safety is further enhanced.

Further, since the gas passage can be constructed with a simple shape of the groove, the processing of the stopper is easy, and the root of the cylindrical projection is the positioning of the glass tube when the glass tube is mounted.
Workability is improved and cost can be reduced.

Further, the entrance outside the passage is viewed from the outside of the stopper.
Therefore, it looks good in terms of design.

The invention described in claim 22 is
In the invention described in any one of 2, 9, 12 to 21,
And the total length of the first glass tube is the total length of the second glass tube.
The first glass tube is
And first attach each end of the second glass tube to the stopper first
When attaching the other end to the other stopper
The end of the second glass tube projects from the end of the second glass tube
Since it can be inserted into the stopper while positioning sequentially, further work
Sexuality improves.

The invention as set forth in claim 23,
According to the invention described in any one of 1, 2, 8, 9, and 12,
And the water dripping from the evaporator is
Vertically above the glass tube so that it does not hit the surface of the lath tube
Is provided with a drain wall extending downward at the edge along the longitudinal direction.
Placed the umbrella, and the height of the drainage wall is 0.5 mm or less.
It is set to 5 mm or less above and between the umbrella and the glass tube.
The air that stays in the glass easily convection naturally,
The temperature can be suppressed below the ignition temperature of flammable refrigerant.
It

[Brief description of drawings]

FIG. 1 is a sectional view of essential parts showing a defrost heater for a refrigerator according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional perspective view of essential parts of the defrosting heater for the refrigerator according to the same embodiment.

FIG. 3 is a schematic representation of a refrigeration system of refrigerators of the same embodiment

FIG. 4 is a perspective view showing another shape of the cylindrical protrusion of the defrost heater of the refrigerator according to the same embodiment.

FIG. 5 is a cross-sectional view of essential parts showing a defrosting heater for a refrigerator according to the same embodiment.

FIG. 6 is a cross-sectional perspective view of essential parts of the defrosting heater for the refrigerator according to the embodiment.

FIG. 7 is a perspective view showing the groove shape of the cylindrical protrusion of the defrosting heater for the refrigerator according to the same embodiment.

FIG. 8 is a cross-sectional view of essential parts showing a defrost heater for a refrigerator according to Embodiment 2 of the present invention.

FIG. 9 is a cross-sectional view showing a state in which a plug having another shape is used in the defrosting heater for the refrigerator according to the same embodiment.

FIG. 10 is a perspective view showing another shape of the defrost heater stopper of the refrigerator according to the embodiment.

FIG. 11 is a perspective view showing another shape of the stopper of the defrost heater of the refrigerator according to the same embodiment.

FIG. 12 is a perspective view showing another shape of the stopper of the defrost heater of the refrigerator according to the same embodiment.

FIG. 13 is a perspective view showing another shape of the stopper of the defrost heater of the refrigerator according to the same embodiment.

FIG. 14 is a cross-sectional view of essential parts showing a defrost heater for a refrigerator according to Embodiment 3 of the present invention.

FIG. 15 is a perspective view of essential parts showing a defrosting heater for a refrigerator according to the same embodiment.

FIG. 16 is a schematic vertical sectional view of a refrigerator including a conventional defrost heater.

[Explanation of symbols]

51 Defrost Heater 52 Heater Wire 53 First Glass Tube 53a Glass Tube End Surface 54 Second Glass Tube 55 Lead Wire 56 Connecting Tube (Connecting Part) 57, 70, 80 Positioning Plate 57a Vent 58, 90 Plug 58a Gap 59 , 91 cylindrical protrusions 59a, 91a inner circumference 59b, 91b outer circumference 71 sleeve 71a vent hole 92 groove 100, 200, 300, 400, 500, 600, 7
00 Stoppers 101, 201, 301, 401, 501, 601, 7
01 Plug body 102, 202, 302, 402, 502, 602, 7
02 cylindrical protrusions 102a, 202a, 302a, 402a, 502a,
602a, 702a inner circumference 102b, 202b, 402b, 502b, 602b,
702b outer circumference 103, 204, 304, 404, 505, 604, 7
03 passage 104 space 203, 303, 403, 503, 504, 603 groove 302c convex portion 402b outer circumference (second outer circumference) 402c outer circumference (first outer circumference) 705 umbrella 705c draining wall

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazu Takeuchi ▲ OK ▼ 4-5 Takaida Hondori, Higashi-Osaka City, Osaka Prefecture Matsushita Refrigerating Machinery Co., Ltd. (56) Reference JP-A-11-257831 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25D 21/08

Claims (23)

(57) [Claims] 1. A defrost heater for removing frost adhered to and deposited on an evaporator of a refrigeration cycle enclosing a flammable refrigerant by heating, the defrost heater being installed in a glass tube and inside the glass tube. The heater wire made of metal resistor and the lead wire insertion hole are shaped.
A plug made are covering the openings at both ends of the glass tube, the Li
Through the lead wire insertion hole and connected to the end of the heater wire.
At the connection between the lead wire and the heater wire and the lead wire.
Provided and held by the plug to move the connection
And a positioning plate for preventing the surface temperature of the glass tube is adjusted to be lower than the ignition temperature of the flammable refrigerant, the size of the gap formed by the stopper and the positioning plate.
A flammable refrigerant is formed by the stopper and the positioning plate.
Even if it enters the heater wire side and ignites through the gap
The flame is transmitted through the gap formed by the stopper and the positioning plate.
Refrigerator set to a size that does not sow . 2. A defrost heater for removing frost adhered and accumulated on an evaporator of a refrigeration cycle enclosing a combustible refrigerant by heating, wherein the defrost heater includes a first glass tube and the first defroster. A second glass tube installed so as to cover the outer circumference of the glass tube;
A heater wire made of a metal resistor installed inside the first glass tube, a plug having a lead wire insertion hole and covering both end openings of the first glass tube and the second glass tube ,
Connect to the end of the heater wire through the lead wire insertion hole
Of the lead wire, the heater wire and the lead wire
The connection part is provided on the connection part and is held by the stopper, and the connection part is transferred.
A positioning plate for preventing movement, and a size of a gap formed between the stopper and the positioning plate
A flammable refrigerant is formed by the stopper and the positioning plate.
Even if it enters the heater wire side and ignites through the gap
The flame is transmitted through the gap formed by the stopper and the positioning plate.
Refrigerator set to a size that does not sow . 3. A stopper and a positioning plate viewed from the end face side of the glass tube.
The cross-sectional area of the gap formed by
The refrigerator according to claim 1 or 2, wherein the refrigerator has a thickness of less than a remeter . 4. A positioning plate is provided with a ventilation hole, and the positioning is performed.
Make sure that the edges of the baffle are in intimate contact with the inside of the stopper to transfer gas between the inside and outside
The movement is performed through the ventilation hole.
The refrigerator according to claim 1 or 2 . 5. The area of the vent hole is 7.1 square millimeters.
The refrigerator according to claim 4 , wherein: 6. A positioning plate having a ventilation hole for the positioning.
Three with a total length of 5 mm or more that penetrates the female plate
The refrigerator according to claim 1 or 2 , wherein a refrigerator is provided. 7. The positioning plate has at least 20 mesh or more.
The upper wire mesh structure is shaped like a coil in the heater wire.
The formed part is the end surface of the glass tube that covers the heater wire.
At least 20 mm or more apart from claim 1 or claim
The refrigerator according to Item 2 . 8. A refrigerating cycle vaporizer containing a flammable refrigerant.
Defrost heater that removes frost that has adhered to and accumulated on the generator by heating
The defrosting heater includes a glass tube and the inside of the glass tube.
Insert the heater wire consisting of the installed metal resistor and the lead wire
A stopper formed with an inlet hole and covering both end openings of the glass tube,
Connect to the end of the heater wire through the lead wire insertion hole
And a surface temperature of the glass tube is lower than the ignition temperature of the flammable refrigerant.
Is adjusted so that the difference between the lead wire insertion hole and the outer diameter of the lead wire
The gap formed is the above-mentioned
The gas in the inner space of the glass tube to the outside,
When the inside of the defroster is decompressed due to a temperature decrease, the defrost heater
ー Allow ambient air to flow into the glass tube and
When the flammable refrigerant flows into the lath tube and the heater is energized,
Ignition outside the glass tube even if ignited inside the glass tube,
Refrigerator characterized by having a cross-sectional area to prevent transmission . 9. A steam for a refrigeration cycle in which a flammable refrigerant is enclosed.
Defrost heater that removes frost that has adhered to and accumulated on the generator by heating
The defrosting heater includes a first glass tube and a first glass tube.
A second glass tube installed so as to cover the outer periphery of the lath tube,
It consists of a metallic resistor installed inside the first glass tube.
The heater wire and the lead wire insertion hole are formed, and the first gas
A stopper for covering the lath tube and the openings at both ends of the second glass tube;
Connect to the end of the heater wire through the lead wire insertion hole
And a lead wire to be inserted, the difference between the lead wire insertion hole and the outer diameter of the lead wire
The clearance that is formed is that of the first
The gas in the inner space of the glass tube of
When the inside of the glass tube of No. 1 is decompressed due to temperature decrease
The outside air around the defrost heater is placed inside the first glass tube.
And the flammable refrigerant flows into the first glass tube.
And ignites in the first glass tube when the heater is energized
Even if it prevents the ignition and propagation to the outside of the first glass tube
A refrigerator characterized by having a cross-sectional area . 10. A lead wire insertion hole and an outer diameter of the lead wire.
The cross-sectional area at any position of the clearance formed by the difference
Claims 1 to 7 below 7.1 square millimeters
The refrigerator according to claim 9 . 11. A lead wire located in a lead wire insertion hole.
And the total of the connecting parts that connect the lead wires and heater wires
Has a length of at least 6 mm and is along the insertion hole.
The refrigerator according to any one of claims 1 to 10 , wherein: 12. A refrigeration cycle in which a flammable refrigerant is enclosed.
Defroster that removes frost that has adhered to and accumulated on the evaporator by heating
The defrosting heater includes a first glass tube and the first gas tube.
A second glass tube installed so as to cover the outer periphery of the lath tube,
It consists of a metallic resistor installed inside the first glass tube.
Heater wire, the first glass tube and the second glass
A stopper for covering the opening portions at both ends of the tube, the inner peripheral surface of the first glass tube and the
The gas in the space formed by the peripheral surface and the plug is heated by the temperature rise.
When expanded, the gas in the space is discharged to the outside,
When the space is decompressed due to temperature decrease
A refrigerator having a passage provided therein to the stopper . 13. A passage has a cross-sectional area of 7.1 square millimeters.
The refrigerator according to claim 12, which is as follows . 14. The stopper has an inner peripheral surface which is the outer periphery of the first glass tube.
And the outer peripheral surface adheres to the inner peripheral surface of the second glass tube.
A cylindrical protrusion is provided, The said protrusion is characterized by the above-mentioned.
The refrigerator according to any one of 2 and 13 . 15. The stopper has an inner circumference into which the first glass tube is inserted.
And a cylindrical protrusion having an outer circumference that enters the second glass tube
And a plug body that holds the root of the cylindrical protrusion.
It is, on the outer periphery of the cylindrical projection longitudinally from root to tip
A groove to be cut longitudinally is provided, and by the second glass tube and the groove,
With the root of the cylindrical projection to form a gas passage
A predetermined distance from the end face of the second glass tube
The refrigerator according to claim 12 , wherein the refrigerator is a refrigerator. 16. The cylindrical projection is provided at the base of the cylindrical projection.
Project a predetermined distance from the root of the
A special feature is that a projection is provided to stop the end surface of the lath tube at a predetermined position.
The refrigerator according to claim 15, which is used as a characteristic . 17. The plug comprises a cylindrical protrusion and the cylindrical protrusion.
It consists of a plug body that holds the root of the
The circumference consists of two outer surfaces with different diameters, and the outer circumference on the root side
Is the first outer circumference and its diameter is larger than the inner diameter of the second glass tube.
Set the diameter and set the other circumference as the second circumference
Is set to have the same size as the inner diameter of the second glass tube, and the cylindrical protrusion has the second outer portion from the root of the first outer periphery.
Provide a common groove that extends longitudinally to the tip of the circumference,
By the step portion formed between the first outer circumference and the second outer circumference,
The end surface of the second glass tube is a predetermined distance from the stopper body.
Is stopped at a position away from the second glass tube and the front
A gas passage is formed by a groove.
The refrigerator according to claim 12 or 13 . 18. The stopper has an inner circumference into which the first glass tube is inserted.
And a cylindrical protrusion having an outer circumference that enters the second glass tube
And a plug body that holds the root of the cylindrical protrusion.
It is, on the outer periphery of the cylindrical projection longitudinally from root to tip
The longitudinal grooves provided, the root of the cylindrical protrusion before hexene body
The second glass tube is provided with a groove that originally intersects with the groove.
And the groove forms a gas passage.
The refrigerator according to claim 12 or 13 . 19. The entrance outside the passage faces downward.
Claims 12, 13, 15 to 18 characterized in that
The refrigerator according to any one of claims. 20. The stopper has a hole and a first glass tube inserted therein.
A circle consisting of the inner circumference and the outer circumference that enters the second glass tube.
From the root to the tip on the cylindrical protrusion and the inner circumference of the cylindrical protrusion
A groove extending longitudinally and communicating with the hole;
Glass tube, the groove and the hole form a gas passage.
The refrigerator according to claim 12 , wherein the refrigerator is a refrigerator. 21. The plug is connected to the end of the heater wire
The lead wire insertion hole into which the lead wire is inserted, and the first glass
Inner circumference into which the tube enters and outer circumference into the second glass tube
Holds the base of the cylindrical protrusion and the cylindrical protrusion.
The main body of the cylindrical projection, and extends in the longitudinal direction from the root to the tip on the inner circumference of the cylindrical protrusion.
The groove to be cut and the groove at the root of the inner circumference intersect with the groove and
Connect to the lead wire insertion hole where the lead wire is inserted.
Groove is provided, and the first glass tube, the groove, and the lead are provided.
A contraction characterized in that the wire insertion hole forms a gas passage.
The refrigerator according to claim 12 or claim 13 . 22. The entire length of the first glass tube is set to the second glass
The pipe is made longer than the entire length of the pipe.
The refrigerator according to any one of 12 to 21 . 23. A draining wall extending downward is provided vertically above the glass tube so that the water dripping from the evaporator does not hit the surface of the glass tube of the defrost heater. the umbrella is arranged, the draining height claims set at 0.5mm 5mm or more or less of the wall 1, a refrigerator according to any one of 2,8,9,12.