KR102521938B1 - Defrosting device - Google Patents

Abstract

The present invention, the first inner flow path, the second inner flow path and the heater receiving portion formed through the heater case so that they do not communicate with each other; a first heat pipe whose both ends are inserted into the heater case through an inlet and an outlet of the first inner flow path opened at both ends of the heater case, and communicated with the first inner flow path; a second heat pipe having both ends inserted into the heater case through an inlet and an outlet of the second inner flow path opened at both ends of the heater case and communicating with the second inner flow path; And a heater inserted into the heater accommodating part to heat the working fluid in the first and second inner flow passages, wherein the heater accommodating part discloses a defrosting device formed between the first inner flow passage and the second inner flow passage. do.

Description

Defrosting device {DEFROSTING DEVICE}

The present invention relates to a defrosting device for removing frost formed on an evaporator provided in a refrigerating cycle.

A refrigerator is a device that stores food stored therein at a low temperature using cold air generated by a refrigeration cycle in which processes of compression, condensation, expansion, and evaporation are continuously performed.

The refrigerating cycle in the refrigerator compartment consists of a compressor that compresses the refrigerant, a condenser that condenses the high-temperature and high-pressure refrigerant compressed from the compressor through heat radiation, and a cooling action that absorbs latent heat from the surroundings while the refrigerant provided from the condenser evaporates. It contains an evaporator that cools the air. A capillary tube or an expansion valve is provided between the condenser and the evaporator to increase the flow rate of the refrigerant and lower the pressure so that the refrigerant flowing into the evaporator can easily evaporate.

As such, the evaporator provided in the refrigeration cycle lowers the ambient temperature by using cool air generated by the circulation of the refrigerant flowing through the cooling pipe. In this process, when a temperature difference with ambient air occurs, moisture in the air is condensed and frozen on the surface of the cooling pipe, and sometimes develops into frost. Frost implanted in the evaporator acts as a factor that lowers the heat exchange efficiency of the evaporator.

As a defrosting operation to remove frost formed on the evaporator, a defrosting method using a hot wire has been conventionally used. However, in the defrosting structure using a hot wire, an appropriate temperature required for defrosting is not transmitted to a specific part of the evaporator, causing a problem of energy loss.

Recently, a defrosting device having a new structure in which defrosting is performed while a working fluid heated by a heater flows through a heat pipe has been developed.

The heat generated by the heater is dissipated in omnidirectional direction of the heater. Therefore, when the internal flow path through which the working fluid flows is concentrated on one side of the heater, there is a problem in that heat generated on the other side of the heater is lost.

In addition, in a structure in which a heater is mounted on a heater case to transfer heat to an internal passage through which a working fluid flows, heat transfer from the heater to the working fluid can be increased only when the heater is tightly adhered to the heater case. However, the structure in which the heater is attached to the heater case is poor in assemblability, and there is a concern that moisture may penetrate into the heater.

Therefore, research is being conducted on a new heater fixing structure that can easily and firmly fix the heater to the heater case and can reduce assembly defects.

Meanwhile, in the above structure, the heater is usually disposed below the evaporator, and defrost water generated due to defrosting on the arrangement may flow down to the heater. Since the heater is an electronic component, moisture permeation must be prevented in order to secure its reliability.

In addition, in order to stabilize the circulation of the working fluid and improve the performance of the defrosting device, it is most important to increase heat transfer from the heater to the working fluid.

A first object of the present invention is to provide a structure capable of reducing heat loss of a heater for heating a working fluid.

A second object of the present invention is to provide a heater fixing structure capable of firmly fixing a heater to a heater case and reducing assembly defects.

A third object of the present invention is to provide a structure capable of preventing penetration of moisture into a heater.

A fourth object of the present invention is to provide a heater case having a novel structure in which heat transfer from a heater to a working fluid can be increased.

In order to achieve the first object of the present invention, the defrosting device of the present invention, the first inner flow path, the second inner flow path and the heater housing formed through the heater so that the heater is not in communication with each other; a first heat pipe whose both ends are inserted into the heater case through an inlet and an outlet of the first inner flow path opened at both ends of the heater case, and communicated with the first inner flow path; a second heat pipe having both ends inserted into the heater case through an inlet and an outlet of the second inner flow path opened at both ends of the heater case and communicating with the second inner flow path; and a heater inserted into the heater accommodating part to heat the working fluid in the first and second inner passages, wherein the heater accommodating part is formed between the first inner passage and the second inner passage.

The first heat pipe is disposed on the front side of the evaporator, and the second heat pipe is disposed on the rear side of the evaporator.

When the heater case is disposed at a position lower than the lowermost end of the cooling pipe of the evaporator, the first and second inner flow passages extend long in the left and right directions of the evaporator, and the first and second inner flow passages are disposed in the evaporator. It may be disposed in the front and rear directions of the evaporator corresponding to the first and second heat pipes respectively disposed on the front and rear sides of the heat pipe.

The first heat pipe forms a closed-loop circulation passage together with the first inner passage, and the second heat pipe forms a closed-loop circulation passage together with the second inner passage.

The heater case is provided with a first working fluid inlet for injecting the working fluid into the first inner passage and a second working fluid inlet for injecting the working fluid into the second inner passage.

When the heater case is disposed outside the support of the evaporator, the first and second inner flow passages extend long in the vertical direction of the evaporator, and the first and second inner flow passages are formed on the front and rear sides of the evaporator. It may be disposed in the front and rear directions of the evaporator corresponding to the first and second heat pipes respectively disposed.

In order to achieve the second object of the present invention, the defrosting device of the present invention, the first inner flow path, the second inner flow path and the heater case through which the heater receiving portion is formed so that they do not communicate with each other; a first heat pipe whose both ends are inserted into the heater case through an inlet and an outlet of the first inner flow path opened at both ends of the heater case, and communicated with the first inner flow path; a second heat pipe having both ends inserted into the heater case through an inlet and an outlet of the second inner flow path opened at both ends of the heater case and communicating with the second inner flow path; and a heater inserted into the heater accommodating part to heat the working fluid in the first and second inner passages, so that the heater accommodating part can be crushed into a predetermined shape when the heater case is pressed. Bend grooves recessed inward toward the heater accommodating portion are formed on the upper and lower surfaces.

In a state in which the heater case is pressed, the upper and lower surfaces of the heater accommodating part are bent inward around the bending groove, and the heater is in close contact with the left inner surface and the right inner surface of the heater accommodating part.

The bending groove may extend along a longitudinal direction of the heater case.

The bending groove may be formed at an intermediate point of the heater accommodating part.

The bending groove may have a rounded shape.

In order to achieve the third object of the present invention, the defrosting device of the present invention, the first inner flow path, the second inner flow path and the heater case through which the heater receiving portion is formed so that they do not communicate with each other; a first heat pipe whose both ends are inserted into the heater case through an inlet and an outlet of the first inner flow path opened at both ends of the heater case, and communicated with the first inner flow path; a second heat pipe having both ends inserted into the heater case through an inlet and an outlet of the second inner flow path opened at both ends of the heater case and communicating with the second inner flow path; and a heater inserted into the heater accommodating part to heat the working fluid in the first and second inner passages, wherein the heater has a PTC (Positive Temperature Coefficient) thermistor having a characteristic in which resistance increases as temperature increases. ; first and second electrode plates disposed to face each other with the PTC thermistor therebetween; and a first thermal bonding part and a second thermal bonding part which accommodate the first and second electrode plates in which the PTC thermistor is interposed, and are respectively formed on the front and rear sides. It includes an insulating film that seals the inside through.

The heater further includes a lead wire electrically connecting the first and second electrode plates and the power supply unit, and a part of the second thermal fusion portion is formed by thermal fusion of the insulating film and the lead wire. .

A sealing member is filled in the heater accommodating portion in which the heater is accommodated.

In order to achieve the fourth object of the present invention, the defrosting apparatus of the present invention, the first inner flow path, the second inner flow path and the heater case through which the heater receiving portion is formed so as not to communicate with each other; a first heat pipe whose both ends are inserted into the heater case through an inlet and an outlet of the first inner flow path opened at both ends of the heater case, and communicated with the first inner flow path; a second heat pipe having both ends inserted into the heater case through an inlet and an outlet of the second inner flow path opened at both ends of the heater case and communicating with the second inner flow path; and a heater inserted into the heater accommodating part to heat the working fluid in the first and second inner passages, wherein grooves are repeatedly formed along the circumference of the first and second inner passages, and the grooves are formed in the first and second inner passages. It extends along the longitudinal direction of the heater case.

The first and second internal passages pass through the center and are divided into a first part and a second part based on a horizontal plane parallel to the heater, and the groove is formed in a part adjacent to the heater among the first and second parts. can

The effects of the present invention obtained through the above solutions are as follows.

First, since the first inner flow path and the second inner flow path are formed on both sides of the heater accommodating part, heat dissipated in both directions of the heater is transferred to the first inner flow path and the second inner flow path, respectively, so that heat loss can be reduced. .

Second, since the heater case is bent inwardly by the bending grooves formed on both sides of the heater case, the heater accommodated in the heater accommodating portion can be firmly adhered to the inner surface of the heater accommodating portion. As a result, the contact area between the heater and the heater case is increased, so that heat transfer efficiency from the heater to the working fluid can be improved.

In addition, as the heater accommodating portion is pressed in an intended shape by the bending groove, assembly defects can be reduced.

Third, since the insulating film of the heater is sealed while accommodating the PTC thermistor and the first and second electrode plates, penetration of moisture into the insulating film can be prevented.

In addition, secondary sealing of the heater may be performed by filling the sealing member in the heater accommodating portion in which the heater is accommodated.

Fourth, when grooves are repeatedly formed along the circumference of the inner flow path of the heater case, the heating area of the working fluid increases, and thus the working pressure of the working fluid increases, stabilizing the circulation of the working fluid and improving the reliability of defrosting. It can be done.

1 is a longitudinal sectional view schematically showing the configuration of a refrigerator according to an embodiment of the present invention;
2 and 3 are front and perspective views showing an example of a defrosting device applied to the refrigerator of FIG. 1;
4 is a conceptual view showing an example of the heating unit shown in FIG. 3;
5 is an exploded perspective view of the heating unit shown in FIG. 4;
6 is a front view of the heater case shown in FIG. 5;
Figure 7 is a conceptual view showing a process of fixing the heater shown in Figure 5 to the heater receiving portion through pressing.
Fig. 8 is a cross-sectional view of the heater case shown in Fig. 4 taken along line AA;
Fig. 9 is a cross-sectional view of the heater case shown in Fig. 4 taken along line BB;
10 is a cross-sectional view showing the internal structure of the heating unit shown in FIG. 4;
11 is a conceptual view showing an example of the heater shown in FIG. 5;
12 is an exploded perspective view of the heater shown in FIG. 11;
13 is a graph showing resistance-temperature characteristics of the PTC thermistor shown in FIG. 12;
14 is a graph showing current-voltage characteristics of the PTC thermistor shown in FIG. 12;
15 and 16 are conceptual diagrams for explaining the circulation of the working fluid before and after the operation of the heater.
17 and 18 are front views showing a modified example of the heater case shown in FIG. 6;
19 is a perspective view showing another example of a defrosting device applied to the refrigerator of FIG. 1;

Hereinafter, a defrosting device related to the present invention will be described in more detail with reference to the drawings.

In this specification, the same or similar reference numerals are assigned to the same or similar components even in different embodiments, and overlapping descriptions thereof will be omitted.

In addition, a structure applied to one embodiment may be equally applied to another embodiment as long as there is no structural or functional contradiction between different embodiments.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions thereof will be omitted.

The accompanying drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the accompanying drawings, and all changes and equivalents included in the spirit and technical scope of the present invention are included. It should be understood to include water or substitutes.

1 is a longitudinal cross-sectional view schematically showing the configuration of a refrigerator 100 according to an embodiment of the present invention.

The refrigerator 100 is a device for storing food stored therein at a low temperature using cold air generated by a refrigeration cycle in which processes of compression, condensation, expansion, and evaporation are continuously performed.

As shown, the refrigerator body 110 has a storage space for storing food therein. The storage space may be separated by a partition wall 111 and may be divided into a refrigerating compartment 112 and a freezing compartment 113 according to set temperatures.

In this embodiment, a top mount type refrigerator in which the freezing chamber 113 is disposed above the refrigerating chamber 112 is shown, but the present invention is not limited thereto. The present invention can also be applied to a side-by-side type refrigerator in which a refrigerating compartment and a freezing compartment are disposed left and right, a bottom freezer type refrigerator in which a refrigerating compartment is provided at the top and a freezing compartment is provided at the bottom, and the like. can

A door is connected to the refrigerator body 110 to open and close the front opening of the refrigerator body 110 . In this drawing, it is shown that the refrigerating compartment door 114 and the freezing compartment door 115 are configured to open and close the front portions of the refrigerating compartment 112 and the freezing compartment 113, respectively. The door may be configured in various ways, such as a rotary door rotatably connected to the refrigerator body 110 and a drawer-type door slidably connected to the refrigerator body 110 .

The refrigerator body 110 includes at least one storage unit 180 (eg, a shelf 181, a tray 182, a basket 183, etc.) for efficient use of internal storage space. For example, the shelf 181 and the tray 182 may be installed inside the refrigerator body 110, and the basket 183 may be installed inside the door 114 connected to the refrigerator body 110.

Meanwhile, a cooling chamber 116 equipped with an evaporator 130 and a blowing fan 140 is provided at a rear side of the freezing chamber 113 . A refrigerator compartment return duct 111a and a freezer compartment return duct 111b are formed in the partition wall 111 to allow air from the refrigerator compartment 112 and the freezer compartment 113 to be sucked in and returned to the cooling compartment 116 side. In addition, a cold air duct 150 communicating with the freezing compartment 113 and having a plurality of cold air outlets 150a is installed at the rear side of the refrigerating compartment 112 .

A machine room 117 is provided on the lower side of the rear surface of the refrigerator body 110, and a compressor 160 and a condenser (not shown) are provided inside the machine room 117.

Meanwhile, the air in the refrigerating chamber 112 and the freezing chamber 113 is blown by the blowing fan 140 of the cooling chamber 116 through the refrigerating chamber return duct 111a and the freezing chamber return duct 111b of the partition 111 to the cooling chamber ( 116), undergoes heat exchange with the evaporator 130, and is discharged to the refrigerating chamber 112 and the freezing chamber 113 through the cold air discharge port 150a of the cold air duct 150, which is repeatedly performed. At this time, frost is formed on the surface of the evaporator 130 due to a temperature difference between the circulating air re-introduced through the refrigerating chamber return duct 111a and the freezing chamber return duct 111b.

In order to remove this frost, the evaporator 130 is provided with a defrosting device 170, and the water removed by the defrosting device 170, that is, the defrost water, passes through the defrost water discharge pipe 118 to the bottom of the refrigerator body 110. Water is collected in the side defrost water receiver (not shown).

Hereinafter, the defrosting device 170 will be described in more detail.

2 and 3 are front and perspective views showing an example of a defrosting device 170 applied to the refrigerator 100 of FIG. 1 .

Referring to FIGS. 2 and 3 , the evaporator 130 includes a cooling pipe 131 (cooling pipe), a plurality of cooling fins 132 and a support 133 .

The cooling pipe 131 is repeatedly bent in a zigzag shape to form a plurality of steps (columns), and a refrigerant is filled therein. The cooling pipe 131 may be formed of an aluminum material.

The cooling pipe 131 may be composed of a combination of a horizontal pipe part and a bending pipe part. The horizontal pipe parts are arranged horizontally to each other to form a plurality of stages, and the horizontal pipe parts of each stage are configured to pass through the cooling fins 132 . The bending pipe unit is configured to communicate the inside by connecting the end of the upper horizontal pipe and the end of the lower horizontal pipe, respectively.

The cooling pipe 131 is supported by passing through the supports 133 provided on the left and right sides of the evaporator 130, respectively. At this time, the bending pipe of the cooling pipe 131 is configured to connect the end of the upper horizontal pipe and the end of the lower horizontal pipe at the outside of the support 133 .

Referring to FIG. 3, in this embodiment, the first cooling pipe 131' and the second cooling pipe 131" are disposed on the front and rear parts of the evaporator 130, respectively, to form two rows. For reference, in FIG. 2, the front first cooling pipe 131' and the rear second cooling pipe 131" are formed in the same shape, so that the second cooling pipe 131" is the first cooling pipe. It is covered by (131').

However, the present invention is not limited thereto. The front first cooling tube 131' and the rear second cooling tube 131" may be formed in different shapes. On the other hand, the cooling tubes 131 may be formed in a single row.

In the cooling pipe 131, a plurality of cooling fins 132 are spaced apart from each other at predetermined intervals along the extending direction of the cooling pipe 131. The cooling fin 132 may be formed of a flat plate made of aluminum, and the cooling tube 131 may be expanded while being inserted into the insertion hole of the cooling fin 132 and firmly inserted into the insertion hole.

A plurality of supports 133 are provided on both left and right sides of the evaporator 130, and each is configured to support the cooling pipe 131 extending vertically along the vertical direction. An insertion groove or an insertion hole into which a heat pipe 172 described later can be inserted and fixed is formed in the support 133 .

The defrosting device 170 is installed in the evaporator 130 to remove frost generated in the evaporator 130 . The defrosting device 170 includes a heating unit 171 and a heat pipe 172 (heat transfer pipe).

The heating unit 171 is disposed below the evaporator 130 and is electrically connected to a controller (not shown) to generate heat when receiving a driving signal from the controller.

The control unit may be configured to apply a driving signal to the heating unit 171 at predetermined time intervals. For example, the control unit stops (OFF) the operation of the compressor 160 and operates (ON) a power supply unit (not shown) after a certain time elapses after the compressor 160 constituting the refrigeration cycle is operated, Power may be supplied to the heater 171b (see FIG. 4).

The control of the controller is not limited to time control. The controller may be configured to apply a driving signal to the heating unit 171 when the detected temperature of the cooling chamber 116 is lower than a preset temperature.

The heat pipe 172 is connected to the heating unit 171 to form a closed-loop flow path through which a working fluid (F) circulates together with the heating unit 171 . The heat pipe 172 may be formed of an aluminum material.

At least a part of the hip pipe 172 is adjacent to the cooling pipe 131 so that heat is dissipated to the cooling pipe 131 of the evaporator 130 by the high-temperature working fluid F heated by the heating unit 171 and transferred thereto. are placed The working fluid (F) is a refrigerant (for example, R-134a, R-600a, etc. ) can be used.

The heat pipe 172 may include a first heat pipe 172' and a second heat pipe 172" respectively disposed on the front and rear sides of the evaporator 130. In this embodiment, the first heat pipe 172' The pipe 172' is disposed in front of the first cooling pipe 131', and the second heat pipe 172" is disposed behind the second cooling pipe 131" to form two rows. there is.

The heat pipe 172 may be configured to be accommodated between a plurality of cooling fins 132 fixed to each end of the cooling pipe 131 . According to the above structure, the heat pipe 172 is disposed between each end of the cooling pipe 131 . In this case, the heat pipe 172 may be configured to contact the cooling fin 132 .

However, the present invention is not limited thereto. For example, the heat pipe 172 may be installed to pass through the plurality of cooling fins 132 . That is, the heat pipe 172 may be expanded while being inserted into the insertion hole of the cooling fin 132 and firmly inserted into the insertion hole. According to the above structure, the heat pipe 172 is disposed to correspond to the cooling pipe 131 .

4 is a conceptual diagram showing an example of the heating unit 171 shown in FIG. 3, FIG. 5 is an exploded perspective view of the heating unit 171 shown in FIG. 4, and FIG. 6 is a heater case shown in FIG. 5 ( 171a) is a front view.

Looking at the heating unit 171 in detail with reference to the drawings, the heating unit 171 includes a heater case 171a and a heater 171b.

The heater case 171a is formed as a single body and has a shape elongated along one direction. In this drawing, it is shown that the heater case 171a is formed to have a rectangular pillar shape. The heater case 171a may be formed of a metal material (eg, aluminum material).

The first inner flow path 171a1, the second inner flow path 171a2, and the heater accommodating portion 171a3 are formed through the heater case 171a so that they do not communicate with each other. The first inner flow path 171a1 and the second inner flow path 171a2 are respectively disposed on both sides of the heater accommodating portion 171a3.

The first inner flow path 171a1 and the second inner flow path 171a2 extend along the longitudinal direction of the heater case 171a and are opened at both ends of the heater case 171a to form outlets 171a1' and 171a2' and an inlet. (171a1", 171a2") respectively. That is, the number of outlets 171a1' and 171a2' and inlets 171a1" and 171a2" corresponding to the number of heat pipes 172 are respectively formed in the heater case 171a1.

Both ends of the first heat pipe 172' are inserted into the heater case 171a through the outlet 171a1' and the inlet 171a1" to communicate with the first internal flow path 171a1, and the second heat Both ends of the pipe 172" are inserted into the heater case 171a through the outlet 171a2' and the inlet 171a2" to communicate with the second internal flow path 171a2.

As such, the heater case 171a connects both ends of the heat pipe 172 to form a closed-loop circulation passage through which the working fluid F can circulate together with the heat pipe 172 . That is, the first heat pipe 172' forms a closed-loop circulation flow path together with the first inner flow path 171a1, and the second heat pipe 172" forms another circulation flow path along with the second inner flow path 171a2. A closed-loop circulation flow path is formed.

One end of the heater case 171a (the front end of the heater case 171a in the drawing) is an exit into which the ends 172c' and 172c" of the first and second heat pipes 172' and 172" are inserted. (171a1', 171a2') are respectively formed. The working fluid F in the first and second internal passages 171a1 and 171a2 heated by the heater 171b flows through the first and second heat pipes 172' and 172 inserted into the outlets 171a1' and 171a2'. ") is discharged to one end (172c', 172c"), respectively.

An inlet into which the other ends 172d' and 172d" of the first and second heat pipes 172' and 172" are inserted into the other end of the heater case 171a (in the drawing, the rear end of the heater case 171a). (171a1", 171a2") are formed. The working fluid F condensed while passing through the first and second heat pipes 172' and 172" passes through the first and second heat pipes 172' and 172" inserted into the inlets 171a1" and 171a2". are returned to the first and second internal passages 171a1 and 171a2 through the other ends 172d' and 172d" of the

A heater accommodating portion 171a3 into which the heater 171b is inserted is formed in the heater case 171a. The heater accommodating portion 171a3 is formed between the first inner flow passage 171a1 and the second inner flow passage 171a2 and penetrates the heater case 171a while not communicating with each other. The heater accommodating portion 171a3 may extend in parallel to the first and second internal passages 171a1 and 171a2 and may have an open shape at both ends of the heater case 171a.

In this way, the structure in which the heater accommodating portion 171a3 in the form of an insertion hole is formed in the heater case 171a makes it easy to mount the heater 171b and requires a separate adhesive for attaching the heater 171b to the heater case 171a. It has an advantage in that it is unnecessary.

The heater case 171a may be formed by extrusion molding. In this case, the first and second internal passages 171a1 and 171a2 and the heater accommodating portion 171a3 extend along the extrusion molding direction, that is, in the longitudinal direction of the heater case 171a.

In addition, the inlet 171a1" and the outlet 171a1' of the first internal flow path 171a1 are disposed to face each other, and accordingly, the first heat pipe inserted into the inlet 171a1" and the outlet 171a1' The inlet part 172c' and the return part 172d' of 172' are also disposed to face each other. Similarly, the inlet 171a2" and the outlet 171a2' of the second internal flow path 171a2 are also disposed to face each other, and accordingly, the second heat pipe ( The inlet portion 172c" and the return portion 172d" of 172" are also disposed to face each other.

The inlet 171a1" and the outlet 171a1' of the first inner flow passage 171a1 may have the same size, and the inlet 171a2" and the outlet 171a2' of the second inner flow passage 171a2 may have the same size. can have a size.

The heater case 171a may be disposed on one side of the evaporator 130 where the accumulator 134 is located, on the other side opposite thereto, or at an arbitrary position between the one side and the other side.

The heater case 171a may be disposed adjacent to the lowest end of the cooling pipe 131 . For example, the heater case 171a may be disposed at a position lower than the lowest end of the cooling pipe 131 .

In this embodiment, the heater case 171a is located at one side of the evaporator 130 where the accumulator 134 is located, at a position lower than the lowest end of the cooling pipe 131, in parallel with the cooling pipe 131, the evaporator 130 ) in the horizontal direction (ie, left-right direction).

The first and second internal passages 171a1 and 171a2 correspond to the first and second heat pipes 172' and 172" disposed on the front and rear sides of the evaporator 130, respectively. That is, the second inner flow passage 171a2 may be arranged rearward than the first inner flow passage 171a1 According to the above arrangement, the first and second heat pipes 172', 172") may be connected to the first and second internal passages 171a1 and 171a2, respectively, in a state in which bending is minimized.

Of course, the arrangement of the first and second inner passages 171a1 and 171a2 is not limited thereto. The first and second internal passages 171a1 and 171a2 may be disposed in the vertical direction of the evaporator 130 . That is, the first inner flow path 171a1 may be disposed above the second inner flow path 171a2, and the first inner flow path 171a1 may be disposed below the second inner flow path 171a2.

A heater 171b for heating the working fluid F in the first and second inner passages 171a1 and 171a2 is mounted in the heater accommodating part 171a3. The heater 171b is formed to generate heat when power is supplied, and the working fluid F in the first and second inner passages 171a1 and 171a2 receives heat from the heater 171b and is heated to a high temperature. .

The heater 171b may have a shape elongated along the extension direction of the heater accommodating portion 171a3. The heater 171b may have a flat plate shape having a predetermined thickness.

If the first and second internal flow passages are arranged on one side of the heater accommodating part, the heat generated from one side of the heater may be transferred to the first and second internal flow passages, but the heat generated from the other side of the heater There is a problem with loss. However, as in the present invention, when the heater accommodating portion 171a3 is located between the first inner flow path 171a1 and the second inner flow path 171a2, the heat generated from the heater 171b flows in both directions, that is, the first inner flow path. 171a1 and the second inner passage 171a2, heat loss can be reduced.

With the heater 171b inserted into the heater accommodating portion 171a3, the heater case 171a is pressed by the pressing member 20 (see Fig. 7). The pressing is performed in a direction in which the first inner passage 171a1 and the second inner passage 171a2 come closer to each other.

As the thickness of the heater accommodating portion 171a3 is reduced by the pressing, the heater 171b adheres to the inner surface of the heater accommodating portion 171a3. As shown, the heater 171b is in close contact with the left inner surface and the right inner surface of the heater accommodating part 171a3.

During the pressing, a bending groove 171a5 is formed in the heater case 171a so that the heater case 171a (strictly, the portion where the heater accommodating portion 171a3 is formed) can be bent into a predetermined shape. The portion where the bending groove 171a5 is formed causes deformation during the pressing. That is, the bending groove 171a5 serves to cause the heater case 171a1 to deform in an intended shape.

The bending groove 171a5 has a shape recessed inward from the outer surface of the heater case 171a toward the heater accommodating portion 171a3. In this figure, it is shown that the bending groove 171a5 is formed on the upper and lower surfaces of the heater case 171a defining the upper and lower sides of the heater accommodating portion 171a3, respectively.

The heater accommodating portion 171a3 is formed as an empty space having a wide width (up and down direction in the drawing) and a low height (L1, in the left and right direction in the drawing) corresponding to the heater 171b having a plate shape, and the bending groove 171a5 is It is positioned to correspond to the upper and lower sides of the heater accommodating part 171a3, respectively. That is, the bending grooves 171a5 are respectively located above and below the heater 171b accommodated in the heater accommodating part 171a3.

The bending groove 171a5 may extend along the longitudinal direction of the heater case 171a. As shown, the bending groove 171a5 may be formed from the front end to the rear end of the heater case 171a1.

The bending groove 171a5 may have a notch shape in which the width decreases toward the inside, that is, toward the heater accommodating portion 171a3. The cross section of the bending groove 171a5 may have a pointed shape or may have a rounded shape as shown. Alternatively, the bending groove 171a5 may have a recessed shape while maintaining the same width.

The bending groove 171a5 may be formed during extrusion of the heater case 171a or may be formed through cutting after the heater case 171a is extruded.

When the heater case 171a is pressed by the pressing member, the upper and lower surfaces of the heater case 171a1 defining the heater accommodating portion 171a3 are bent inward around the bending groove 171a5. During the bending process, the heater case 171a is crushed, and the height L1 of the heater accommodating portion 171a3 is reduced.

When the height L1 of the heater accommodating portion 171a3 is reduced to a certain level, the heater 171b accommodated in the heater accommodating portion 171a3 is connected to the left inner surface of the heater case 171a1 defining the heater accommodating portion 171a3. It is pressed by the right inner surface and firmly fixed. Therefore, the heater 171b does not fall out of the heater accommodating part 171a3 without a separate fixing means.

The bending groove 171a5 may be formed at a point corresponding to the 1/2 height L1/2 of the heater accommodating portion 171a3. That is, the left and right portions of the heater accommodating portion 171a3 may have the same height L1/2 based on the center line CL of the bending groove 171a5. According to this, during pressing, the left and right portions of the heater accommodating portion 171a3 may be crushed at the same rate based on the center line CL of the bending groove 171a5.

The degree of pressing by the pressing member 20 may vary according to the thickness of the heater 171b. That is, pressing may be performed such that the height of the heater accommodating portion 171a3 is reduced to correspond to the thickness of the heater 171b.

With the above structure, the heater 171b can be firmly fixed in the heater accommodating portion 171a3. In addition, the heater 171b divides the first inner passage 171a1 and the heater accommodating part 171a3 on the left inner surface of the heater accommodating portion 171a3, and the second internal conduit 171a2 and the heater accommodating portion 171a3. By being in close contact with the right inner surface of the heater accommodating part 171a3 that partitions the heat generated in the heater 171b, more heat is transferred to the first and second inner passages 171a1 and 171a2 to heat the working fluid F. can be used to do

In a state in which the heater 171b is mounted (accommodated and fixed) in the heater accommodating portion 171a3, the sealing member 171a4 may be filled in the heater accommodating portion 171a3 to seal the heater 171b. The sealing member 171a4 fills an empty space where the heater 171b is not disposed.

The sealing member 171a4 may fill a gap between the inner surface of the heater case 171a defining the heater accommodating portion 171a3 and the outer surface of the heater 171b. In addition, the sealing member 171a4 may be disposed to cover openings on both sides of the heater accommodating portion 171a3.

Silicone, urethane, epoxy, etc. may be used as the sealing member 171a4. For example, the sealing structure of the heater 171b may be completed through a curing process after liquid epoxy is filled in the empty space.

Operation and shutdown of the heater 171b may be controlled by time, temperature conditions, and the like. For example, the operation of the heater 171b may be controlled by a time condition, and the operation of the heater 171b may be controlled by a temperature condition.

Specifically, the control unit may stop (OFF) the operation of the compressor 160 and supply power to the heater 171b after a certain time elapses after the evaporator 130 and the compressor 160 constituting the refrigeration cycle are operated. . Accordingly, the heater 171b receives power and generates heat.

The controller may cut off power supplied to the heater 171b when the temperature sensed by the defrost sensor 135 to be described later reaches a predetermined defrost end temperature. Since power is not supplied to the heater 171b, active heat generation of the heater 171b is stopped, and the temperature gradually decreases.

In the defrosting device previously invented, a fuse was used to prevent overheating of the heater. However, in the defrosting device 170 of the present invention, a heater 171b having a characteristic of not generating any more heat by suppressing current due to a rapid increase in resistance at a predetermined temperature or higher is used. That is, the heater 171b itself has a function of preventing overheating. This will be explained in detail later.

A defrost sensor 135 for detecting a temperature for defrosting is provided in the evaporator 130 or the cooling chamber 116 in which the evaporator 130 is disposed. The defrost sensor 135 is installed in a position suitable for representing the temperature of the evaporator 130, and for this purpose, the defrost sensor 135 is preferably located in a part less affected by the temperature rise by the defrost device 170. do.

In this embodiment, it is exemplified that the defrost sensor 135 is mounted on the upper end of the support 133. When the heating unit 171 is disposed adjacent to the support 133 on one side, the defrost sensor 135 may be mounted on the support 133 on the other side farther from the heating unit 171 .

Alternatively, the defrost sensor 135 may be mounted on the inlet side of the cooling pipe 131. The inlet side of the cooling pipe 131 is the part where the temperature is the lowest in the evaporator 130 and is less affected by the temperature rise by the defrosting device 170, and is another position representing the temperature of the evaporator 130. suitable for

When the temperature detected by the defrost sensor 135 reaches a predetermined defrost end temperature, the controller may cut off power supplied to the heater 171b. Since power is not supplied to the heater 171b, active heat generation of the heater 171b is stopped, and the temperature gradually decreases.

Meanwhile, as the working fluid F filled in the first and second internal passages 171a1 and 171a2 is heated by the heater 171b to a high temperature, the working fluid F flows in a direction due to the pressure difference. do.

Specifically, the high-temperature working fluid F heated by the heater 171b and discharged through the outlets 171a1' and 171a2' flows into the heat pipe 172 and moves along the heat pipe 172 while moving along the evaporator 130. ) Transfers heat to the cooling pipe 131. The working fluid F is gradually cooled through this heat exchange process and introduced into the inlets 171a1" and 171a2". The cooled working fluid F is reheated by the heater 171b and then discharged to the outlets 171a1' and 171a2' to repeat the above process. Defrosting of the cooling pipe 131 is performed by this circulation method.

Referring back to FIGS. 2 and 3 , at least a portion of the heat pipe 172 is disposed adjacent to the cooling pipe 131 of the evaporator 130, and the high-temperature working fluid is heated by the heating unit 171 and transported. It is configured to remove frost by transferring heat to the cooling pipe 131 of the evaporator 130 by (F).

The heat pipe 172 may have a repeatedly bent shape (zigzag shape) like the cooling tube 131 . To this end, the heat pipe 172 includes an extension portion 172a and a heat radiation portion 172b.

The extension part 172a forms a passage through which the working fluid F heated by the heating unit 171 is transferred to the upper side of the evaporator 130 . The extension part 172a is connected to the outlets 171a1' and 171a2' of the heater case 171a provided at the lower part of the evaporator 130 and the heat dissipating part 172b provided at the upper part of the evaporator 130.

The extension 172a includes a vertical extension extending upward of the evaporator 130 . The vertical extension extends to the top of the evaporator 130 while being spaced apart from the support 133 on the outside of the support 133 provided on one side of the evaporator 130 .

Meanwhile, depending on the installation position of the heating unit 171, the extension 172a may further include a horizontal extension. For example, when the heating unit 171 is provided at a position spaced apart from the vertical extension, a horizontal extension may be additionally provided to connect the heating unit 171 and the vertical extension.

When the horizontal extension part is connected to the heating unit 171 and formed to be extended, the high-temperature working fluid F passes through the lower part of the evaporator 130, so that the defrosting of the lower cooling pipe 131 of the evaporator 130 occurs. It has the advantage of being seamless.

The heat dissipation part 172b is connected to the extension part 172a extending upward of the evaporator 130 and extends along the cooling pipe 131 of the evaporator 130 in a zigzag pattern. The heat dissipation unit 172b is composed of a combination of a plurality of horizontal pipes 172b' forming vertical stages and a connecting pipe 172b" configured in a U-shaped pipe shape bent to connect them in a zigzag shape.

The extension part 172a or the heat dissipation part 172b may extend to a position adjacent to the accumulator 134 to remove frost accumulated on the accumulator 134 .

As shown, when the vertical extension part is disposed on one side of the evaporator 130 where the accumulator 134 is located, the vertical extension part extends upward to a position adjacent to the accumulator 134, and then cools the cooling pipe 131. It may be configured to be bent and extended downward toward the heat dissipation unit 172b and connected thereto.

On the other hand, when the vertical extension part is disposed on the other side opposite to the one side, the heat dissipation part 172b is connected to the vertical extension part and extends horizontally, then extends upward toward the accumulator 134, and then again the cooling pipe ( 131) may be extended downward.

In a structure in which the heat pipes 172 are composed of first and second heat pipes 172' and 172" forming two rows, the first and second heat pipes 172' and 172" are the first and second heat pipes 172' and 172". They are connected to the outlets 171a1' and 171a2' and the inlets 171a1" and 171a2" of the internal passages 171a1 and 171a2, respectively.

Meanwhile, by the connection structure, the gaseous working fluid F heated by the heating unit 171 flows through the first and second heat pipes 172' and 172" through the outlets 171a1' and 171a2'. The ends of the first and second heat pipes 172' and 172" inserted into the heater case 171a through the outlets 171a1' and 171a2' are functionally (to the heater 171b). The portion into which the high-temperature working fluid F heated by the inlet flows] may be understood as the first and second inlet portions 172c' and 172c".

In addition, the liquid working fluid F cooled while moving the first and second heat pipes 172' and 172" is introduced into the heater case 171a through the inlets 171a1" and 171a2". The other ends of the first and second heat pipes 172' and 172" inserted into the heater case 171a through the inlets 171a1" and 171a2" due to their function [each heat pipe 172 The part where the cooled liquid working fluid F is recovered while moving] may be understood as the first and second return units 172d' and 172d".

That is, one end of the heat pipe 172 inserted into the heater case 171a through the outlets 171a1' and 171a2' is the inlet portion 172c' and 172c" into which the high-temperature working fluid F flows. , and the other end inserted into the heater case 171a through the inlets 171a1" and 171a2" constitutes the return portion 172d' and 172d" in which the cooled working fluid F is recovered.

In this embodiment, the working fluid F heated by the heater 171b is introduced into the inlets 172c' and 172c" and transferred to the top of the evaporator 130 through the extension 172a, and then heat dissipated. After defrosting is performed by transferring heat to the cooling tube 131 while flowing along the part 172b, it is returned to the heater case 171a through the return parts 172d' and 172d", and again by the heater 171b. It is reheated to form a circulation passage through which the heat pipe 172 flows.

The heater case 171a is provided with first and second working fluid injection ports 171a6 and 171a7 for injecting the working fluid F into the first and second internal passages 171a1 and 171a2. The first working fluid injection hole 171a6 passes through the heater case 171a and communicates with the first inner flow passage 171a1, and the second working fluid injection hole 171a7 communicates with the second inner flow passage 171a2.

In order to inject the working fluid F, the first and second working fluid injection pipes 173 and 174 are respectively connected to the first and second working fluid injection ports 171a6 and 171a7. The first and second working fluid injection pipes 173 and 174 may be inserted into the first and second working fluid injection ports 171a6 and 171a7 and then fixed to the heater case 171a by welding to fill the gap. After the working fluid F is filled through the first and second working fluid injection pipes 173 and 174, the first and second working fluid injection pipes 173 and 174 are sealed.

After the working fluid F injected through the first and second working fluid injection ports 171a6 and 171a7 is filled in the first and second internal passages 171a1 and 171a2 of the heater case 171a, A certain amount is filled in the two heat pipes 172' and 172".

FIG. 7 is a conceptual diagram showing a process of fixing the heater 171b shown in FIG. 5 to the heater accommodating portion 171a3 through pressing.

Referring to FIG. 7 , the process includes inserting the heater 171b into the heater accommodating portion 171a3, fixing the heater case 171a to the jig 10, and using the pressing member 20. and pressing the heater case 171a.

First, the heater 171b is inserted into the heater accommodating portion 171a3.

The heater accommodating portion 171a3 is slightly larger than the heater 171b, so that the heater 171b can be easily inserted into the heater accommodating portion 171a3 before the heater case 171a is pressed.

Next, the heater case 171a is fixed to the jig 10 for pressing.

The jig 10 includes a first part 11 and a second part 12. The first part 11 is a part where the pressing member 20 slides. The second part 12 is a surface facing the pressing member 20, perpendicular to the first part 11, and supports the heater case 171a during pressing.

In the fixing step, stoppers S1 and S2 may be disposed on the upper and lower surfaces of the heater case 171a, respectively. In a state where the heater case 171a is fixed to the jig 10, the heater case 171a has a shape protruding from the ends of the stoppers S1 and S2.

Accordingly, the stoppers S1 and S2 serve to limit the pressing degree of the heater case 171a. That is, the pressing member 20 is made to press the heater case 171a only until it comes into contact with the stoppers S1 and S2.

In this drawing, it is shown that the stoppers S1 and S2 are provided separately from the jig 10. As a modified example, the stoppers S1 and S2 may be integrally formed with the jig 10.

Then, the heater case 171a is pressed using the pressing member 20 . The pressing member 20 slides on the first portion 11 of the jig 10 to press the heater case 171a. The pressing may be performed until the pressing member 20 comes into contact with the stoppers S1 and S2.

By the pressing, the heater case 171a is crushed, and the height of the heater accommodating portion 171a3 is reduced. The heater 171b accommodated in the heater accommodating portion 171a3 is firmly fixed by being pressed by the left inner surface and the right inner surface of the heater accommodating portion 171a3. Therefore, the heater 171b does not fall out of the heater accommodating part 171a3 without a separate fixing means.

FIG. 8 is a cross-sectional view of the heater case 171a shown in FIG. 4 taken along the line A-A, FIG. 9 is a cross-sectional view of the heater case 171a shown in FIG. 4 taken along the line B-B, and FIG. It is a cross-sectional view showing the internal structure of the shown heating unit 171.

Referring to FIGS. 8 to 10 , the inlets 172c' and 172c" of the heat pipe 172 are connected to the first and second inner parts formed inside the heater case 171a through the outlets 171a1' and 171a2'. It is inserted into the flow passages 171a1 and 171a2, and the return portions 172d' and 172d" of the heat pipe 172 are connected to the first and second internal flow passages 171a1 and 171a2 through the inlets 171a1" and 171a2". inserted The inlets 172c' and 172c" and the return parts 172d' and 172d" of the heat pipe 172 may be disposed to face each other with the first and second internal passages 171a1 and 171a2 interposed therebetween.

A gap between the heat pipe 172 and the heater case 171a may be filled by welding.

As shown in FIG. 10, in the first and second internal passages 171a1 and 171a2, an active heating part (AHP) corresponding to the portion where the heater 171b is disposed and the heater 171b are not disposed. It is divided into a passive heating part (PHP) corresponding to the part to be. A heater 171b is disposed in a portion corresponding to the active heating unit (AHP) of the heater accommodating portion 171a3, and a sealing member 171a4 is disposed in a portion corresponding to the passive heating unit (PHP).

The active heating part (AHP) is a part directly heated by the heater 171b, and the working fluid (F) in a liquid state is heated in the active heating part (AHP) and phase-changed into a high-temperature gaseous state.

The inlets 172c' and 172c" of the heat pipe 172 may be located within the active heating unit AHP or may be located ahead of the active heating unit AHP (based on the flow direction of the working fluid F). . In this embodiment, the inlets 172c' and 172c" of the heat pipe 172 are located in the active heating unit AHP.

A passive heat generating part PHP is formed behind the active heat generating part AHP (in the opposite direction to the flow of the working fluid F). The passive heating unit PHP is not directly heated by the heater 171b like the active heating unit AHP, but receives heat indirectly and is heated to a certain temperature level. Here, the passive heating unit (PHP) can cause a predetermined temperature increase in the working fluid (F) in the liquid state, but does not have a high enough temperature to change the phase of the working fluid (F) to the gaseous state. That is, in terms of temperature, the active heating part AHP forms a relatively high-temperature part, and the passive heating part PHP forms a relatively low-temperature part.

If the working fluid F is configured to be immediately returned to the high-temperature active heating unit AHP, the recovered working fluid F is heated again and does not smoothly return into the heater case 171a and flows backward. can happen This may interfere with the circulation flow of the working fluid F in the heat pipe 172, causing overheating of the heater 171b.

In order to solve this problem, the return parts 172d' and 172d" of the heat pipe 172 inserted into the inlets 171a1" and 171a2" are in communication with the passive heat generating part (PHP) to heat the heat pipe 172. It is configured so that the working fluid (F) returned after moving does not directly flow into the active heating unit (AHP).

FIG. 11 is a conceptual diagram showing an example of the heater 171b shown in FIG. 5 , and FIG. 12 is an exploded perspective view of the heater 171b shown in FIG. 11 .

As described above, the current of the heater 171b is suppressed due to a rapid increase in resistance at a temperature higher than a preset temperature, so that no more heat is generated. For example, to ensure the safety of the defrosting device 170, the heater 171b may be configured not to generate heat any more when the temperature reaches 280°C.

As such, the heating temperature of the heater 171b is limited by its own characteristics. Accordingly, there is an advantage in that the safety of the heater 171b can be secured without using a fuse as a safety device provided in the existing heating unit.

Referring to FIG. 12 , the heater 171b may include first and second electrode plates 171b1 and 171b2 and a PTC thermistor (Positive Temperature Coefficient Thermistor, 171b3).

The first and second electrode plates 171b1 and 171b2 are disposed to face each other at a predetermined interval. The first and second electrode plates 171b1 and 171b2 are made of a metal material (eg, aluminum material).

Each of the first and second electrode plates 171b1 and 171b2 is electrically connected to a power supply unit (not shown) through a lead wire 171b5. In order to connect the lead wire 171b5 to the first and second electrode plates 171b1 and 171b2, a clamping portion 171b1 wraps and fixes the lead wire 171b5 around the first and second electrode plates 171b1 and 171b2, respectively. ', 171b2') may be formed.

A PTC thermistor 171b3 is interposed between the first electrode plate 171b1 and the second electrode plate 171b2. The PTC thermistor 171b3 has a characteristic in which resistance increases as the temperature increases. The PTC thermistor 171b3 is formed of barium titanate-based ceramics obtained by mixing barium titanate with a small amount (0.1 to 1.5%) of oxides such as lanthanum, yttrium, bismuth, and thorium and firing the mixture.

The PTC thermistor 171b3 has a relatively low resistance value at a low temperature, but has a characteristic that its resistance suddenly increases rapidly when a certain temperature is reached. Therefore, the current is suppressed above the specific temperature.

The temperature at which the temperature-resistance characteristics of the PTC thermistor 171b3 rapidly change is referred to as a Curie point or Curie temperature. The Curie point may be moved to a high temperature side or a low temperature side by adjusting the components of the PTC thermistor 171b3. Therefore, by adjusting the components of the PTC thermistor 171b3, it is possible to manufacture a heater 171b that generates enough heat for defrosting but limits heat generation above a specific temperature.

The method for adjusting the Curie point is as follows. When part of the barium is replaced by lead, the Curie point shifts to the high temperature side. When barium is replaced with strontium or part of titanium is replaced with tin or zirconium, the Curie point shifts toward a lower temperature. In this way, a PTC thermistor 171b3 having heating characteristics suitable for use as a defrosting heater 171b can be made.

A plurality of PTC thermistors 171b3 may be provided. For example, as shown, two xW (watt) PTC thermistors 171b3 may be disposed along one direction to form a 2xW (watt) heater 171b.

The PTC thermistor 171b3 is in close contact with the first and second electrode plates 171b1 and 171b2, respectively. Resistance paste (eg, Ag paste) may be applied to both surfaces of the PTC thermistor 171b3 that come into contact with the first and second electrode plates 171b1 and 171b2, respectively.

Meanwhile, the heater 171b may further include an insulating film 171b4 formed to surround the first and second electrode plates 171b1 and 171b2. As shown, the insulating film 171b4 accommodates the first and second electrode plates 171b1 and 171b2 in which the PTC thermistor 171b3 is interposed, and is sealed to prevent moisture from penetrating into the insulating film 171b4. prevent.

The insulating film 171b4 has a shape in which a portion that is rolled and opened to both sides is sealed by thermal fusion. As shown, in order to seal the insulating film 171b4, a first heat-sealed portion 171b4' is formed on the front side of the insulating film 171b4, and a second heat-sealed portion 171b4" is formed on the rear side of the insulating film 171b4. Here, the lead wire 171b5 extends through the portion where the second thermally fused portion 171b4" is formed. Accordingly, the inside of the insulating film 171b4 is completely separated from the outside.

The first thermal fusion portion 171b4' is formed by thermal fusion of the insulating film 171b4 itself.

The problem is that since the lead wire 171b5 extends from the inside to the outside of the insulating film 171b4, there is a possibility that moisture may penetrate through the gap between the lead wire 171b5 and the insulating film 171b4. In order to solve this problem, a part of the second thermal fusion portion 171b4" through which the lead wire 171b5 passes is formed by thermal fusion between the insulating film 171b4 and the lead wire 171b5. That is, the second thermal fusion. In the portion 171b4", the gap between the lead wire 171b5 and the insulating film 171b4 is eliminated, and the inside of the insulating film 171b4 is completely sealed.

Meanwhile, as described above, the sealing member 171a4 (see FIGS. 4 and 10) may be filled in the heater accommodating portion 171a3 in which the heater 171b is accommodated. That is, the sealing member 171a4 fills the empty space where the heater 171b is not disposed.

The sealing member 171a4 may fill a gap between left and right inner surfaces of the heater accommodating portion 171a3 and both left and right surfaces of the heater 171b. In addition, the sealing member 171a4 may be disposed to cover the front and rear surfaces of the heater 171b.

Silicone, urethane, epoxy, etc. may be used as the sealing member 171a4. For example, after liquid epoxy is filled in the empty space, secondary sealing of the heater 171b may be performed through a curing process.

Hereinafter, the characteristics of the PTC thermistor 171b3 will be described in detail.

FIG. 13 is a graph showing resistance-temperature characteristics of the PTC thermistor 171b3 shown in FIG. 12 .

When the resistance according to the temperature change of the PTC thermistor 171b3 is measured, resistance-temperature characteristics as shown in FIG. 13 are obtained. The PTC thermistor 171b3 exhibits a characteristic in which resistance suddenly increases when the Curie point is reached.

The Curie point at which the temperature-resistance characteristic of the PTC thermistor 171b3 changes rapidly is generally the temperature corresponding to twice the minimum resistance value Rmin or the resistance value Rn at the reference temperature (Tn, room temperature, 25°C). It is defined as the temperature corresponding to the doubling.

In the graph, Tmin is the temperature for the minimum resistance value (Rmin), Ts is the Curie point (switching temperature) at which the resistance value rapidly increases, and Rs means the resistance value at the Curie point.

FIG. 14 is a graph showing current-voltage characteristics of the PTC thermistor 171b3 shown in FIG. 12 .

When a voltage is gradually increased by applying a voltage to the PTC thermistor 171b3, the temperature rises due to self-heating as shown in FIG. When the temperature rises and exceeds the Curie point, resistance increases due to the above-described resistance-temperature characteristics, resulting in a decrease in current. Using this characteristic, the PTC thermistor 171b3 can be used as a heater 171b having a constant temperature heating function and an overcurrent protection function.

Looking at the voltage and current on a log scale, it can be seen that the electrostatic power characteristic appears at the part where the current decreases. Due to this characteristic, the PTC thermistor 171b3 has an advantage of not requiring a separate control circuit.

Due to the characteristics of the PTC thermistor 171b3 described above, the PTC thermistor 171b3 stays in the low resistance region during normal operation and serves as a general fixed resistance, but after exceeding the Curie point due to self-heating, the current is suppressed and further Overheating is prevented. Accordingly, problems such as shortening of life of the heater due to overheating and reduction in efficiency of the evaporator may be solved. In addition, unlike a fuse whose internal components melt and cannot function again when the temperature exceeds a predetermined temperature, the heater 171b using the PTC thermistor 171b has a characteristic of preventing overheating itself, so the defrosting device 170 ) has advantages in terms of maintenance.

15 and 16 are conceptual diagrams for explaining the circulation of the working fluid F before and after the operation of the heater 171b.

First, referring to FIG. 15 , before operation of the heater 171b, the working fluid F is in a liquid state, and is filled up to a predetermined upper level based on the lowest lower end of the heat pipe 172 . For example, in this state, the working fluid F may be filled up to two lower stages of the heat pipe 172 .

When the heater 171b operates, the working fluid F in the heater case 171a is heated by the heater 171b. Referring to FIG. 16 , the working fluid F heated to a high-temperature gaseous state F1 is introduced into the inlets 172c' and 172c" of the heat pipe 172 and flows through the heat pipe 172 while flowing through the cooling pipe 172. 131. The working fluid (F) loses heat in the heat dissipation process and flows in a state (F2) in which liquid and gas coexist, and finally in a liquid state (F3) of the heat pipe 172. It flows into the heating unit 171 through the return units 172d' and 172d". The working fluid F introduced into the heating unit 171 is reheated by the heater 171b, and the flow as described above is repeated (circulated), and in this process, heat is transferred to the evaporator 130 to evaporator ( 130) is removed.

As such, since the working fluid F flows by the pressure difference generated by the heating unit 171 and rapidly circulates through the heat pipe 172, the entire section of the heat pipe 172 reaches a stable operating temperature within a short time. and, accordingly, defrosting can be performed quickly.

Meanwhile, the working fluid F flowing into the inlets 172c' and 172c" is in a high-temperature gaseous state F1 and has the highest temperature during the circulation process of the heat pipe 172. Therefore, such a high-temperature gaseous state If convection of heat by the working fluid F placed in F1 is used, the frost deposited on the evaporator 130 can be removed more efficiently.

For example, the inlets 172c' and 172c" may be disposed at a position relatively lower than or at the same position as the lowest end of the cooling pipe 131 provided in the evaporator 130. According to this, the inlet part ( 172c', 172c"), the high-temperature working fluid (F) not only transfers heat near the lowest end of the cooling pipe 131, but also this heat rises to the cooling pipe 131 adjacent to the lowest end. ) can be transmitted.

Meanwhile, in order for the working fluid F to circulate through the heat pipe 172 while undergoing a phase change, the heat pipe 172 must be filled with the working fluid F in an appropriate amount.

As a result of the experiment, it was confirmed that the temperature of the heating unit 171 rapidly increased over time when the working fluid F was filled to less than 30% of the total internal volume of the circulation passage. This means that the working fluid F is insufficient compared to the total internal volume of the circulation passage.

In addition, when the working fluid F is filled in excess of 40% of the total internal volume of the circulation passage, the temperature of some stages of the heat pipe 172 is stable at the operating temperature [40°C to 50°C (-21°C freezing condition). )] was not reached. This temperature drop becomes more noticeable as the heat pipe 172 approaches the return portions 172d' and 172d". This is because the working fluid F is in a liquid state due to an excess of the working fluid F relative to the total internal volume of the circulation passage. It can be seen that it means that there are many sections flowing to .

When the working fluid F is filled to 30% or more and 40% or less of the total internal volume of the circulation passage, the temperature of the heating unit 171 and the temperature of each stage of the heat pipe 172 are stable over time. temperature could be reached.

At this time, the temperature of each stage of the heat pipe 172 shows a higher temperature as it is closer to the inlet portion 172c' and 172c", and a lower temperature as it is closer to the return portion 172d' and 172d". appear. As the amount of the filled working fluid F decreases, the difference between the temperature (maximum temperature) at the inlet portion 172c' and 172c" and the temperature at the return portion 172d' and 172d" (minimum temperature) also decreases. was

Therefore, the working fluid (F) is filled with 30% or more and 40% or less of the total internal volume of the circulation passage, and the working fluid optimized for each defrosting device 170 according to the heat transfer structure and stability of the defrosting device 170 The filling amount of (F) can be selected.

17 and 18 are front views showing modified examples of the heater case 171a shown in FIG. 6 .

First, referring to FIG. 17 , grooves 271a1a and 271a2a are repeatedly formed along the circumference of the first and second internal channels 271a1 and 271a2 formed in the heater case 271a. Since the heater case 271a is formed by extrusion molding, the grooves 271a1a and 271a2a are formed in the extrusion molding direction, that is, the heater case 271a, like the first and second internal passages 271a1 and 271a2 and the heater accommodating portion 271a2. ) is formed extending along the length direction of.

Since the grooves 271a1a and 271a2a are repeatedly formed along the circumferences of the first and second inner passages 271a1 and 271a2, the heating areas of the first and second inner passages 271a1 and 271a2 may be increased. Therefore, the heat transfer amount transferred to the working fluid F may be increased, and the stability of circulation of the working fluid F and the reliability of defrosting may be improved due to the increase in operating pressure.

In order to maximize the heating area of the first and second internal passages 271a1 and 271a2, it is preferable to set the radius of the grooves 271a1a and 271a2a as small as possible at a level that can be formed by extrusion molding. For example, the radius of the grooves 271a1a and 271a2a may be set to 0.45 mm.

In this figure, it is shown that the grooves 271a1a and 271a2a are continuously formed along the circumferences of the first and second inner passages 271a1 and 271a2. Here, continuous means that when one of the grooves 271a1a and 271a2a ends, the other grooves 271a1a and 271a2a start immediately.

Alternatively, the grooves 271a1a and 271a2a may be repeatedly formed along the circumferences of the first and second inner passages 271a1 and 271a2 at regular intervals.

As a modified example, the grooves 271a1a and 271a2a may be formed only in portions of the first and second internal passages 271a1 and 271a2.

For example, the first and second internal passages 271a1 and 271a2 may be divided into two parts based on a horizontal plane P passing through the center and parallel to the heater accommodating part 271a3. The grooves 271a1a and 271a2a may be formed only in a portion adjacent to the heater accommodating portion 271a3 among the two portions.

On the other hand, the shape of the heater cases 171a and 271a is not limited to a rectangular pillar shape having a rectangular bottom. As shown in FIG. 18, the heater case 371a may be formed in the shape of an octagonal prism having an octagonal bottom. This can be understood as a form in which an inclined surface 371a' is formed by cutting the corners of a heater case having a square pillar shape. In this case, compared to a case having a square pillar shape, the volume is reduced, so material costs are reduced and weight reduction is possible. there is.

19 is a perspective view showing another example of a defrosting device 170 applied to the refrigerator 100 of FIG. 1 . For reference, the description of the heating unit 171 of the previous embodiment may be equally applied to the heating unit 471 to be described later.

Referring to FIG. 19 , the heating unit 471 may be disposed outside the defrosting device 470 . Specifically, the heater case 471a may be located outside the support 433 provided on one side of the evaporator 430, and may extend vertically from the lower side of the evaporator 430 toward the upper side.

The first and second internal passages 471a1 and 471a2 formed in the heater case 471a extend long in the vertical direction of the evaporator 430 . Corresponding to the first and second heat pipes 472' and 472" respectively disposed on the front and rear sides of the evaporator 430, the first and second internal flow passages 471a1 and 471a2 are located in front and rear of the evaporator 430. direction can be placed.

The heater case 471a (strictly, the first and second internal passages 471a1 and 471a2) is connected to the first and second heat pipes 472' and 472", respectively, so that the working fluid F can circulate. To this end, outlets and inlets corresponding to the number of heat pipes 472 are formed on the upper and lower sides of the heater case 471a. , and the inlet is connected to the lowest end of the heat dissipation part 472b of the heat pipe 472 .

The heater is mounted on the heater case 471a and vertically disposed in the vertical direction of the evaporator 430 . As described in the previous embodiments, the heater is accommodated in the heater accommodating portion 471a3 formed to penetrate the heater case 471a, and the heater accommodating portion 471a3 includes the first internal flow path 471a1 and the second internal flow path. It is placed between (471a2). The heater may be firmly fixed in the heater accommodating portion 471a2 by pressing.

The heater is configured to reheat the working fluid (F) recovered through the inlet. The structure in which the first and second internal passages 471a1 and 471a2 extend vertically from the lower side of the evaporator 430 to the upper side is such that the working fluid F in the first and second internal passages 471a1 and 471a2 This is advantageous in that it is heated to form an upward flow, and there is an advantage that the reverse flow of the working fluid F can be prevented.

On the other hand, the working fluid (F) is preferably filled higher than the top of the heater disposed vertically in the heater case (471a). According to this configuration, the defrosting operation can be safely performed without the heating unit 471 being overheated, and the gaseous working fluid F can be stably supplied to the heat pipe 472 .

Claims (13)

In a refrigerator having a defrosting device provided in an evaporator structure having a plurality of cooling fins arranged between supports and a cooling pipe extending in a horizontal direction passing through the cooling fins,
first and second heat pipes extending in a horizontal direction in parallel with the cooling pipe and allowing a working fluid to flow therein;
A first internal flow path formed with an inlet and an outlet spaced apart from the inlet in a straight line direction so that the first heat pipe is fastened to each other, and spaced apart from the inlet and the inlet in a straight line direction so that the second heat pipe is fastened to each other It is formed between the second inner flow passage in which the disposed outlet is formed, the first and second working fluid inlets communicating with the first and second inner flow passages, respectively, and the first and second inner flow passages and has a rectangular cross section. And a heater case having a heater receiving portion formed to pass through in the horizontal direction;
first and second working fluid injection pipes inserted into and fastened to the first and second working fluid injection ports in a direction orthogonal to the first and second heat pipes, respectively;
a heater inserted into the heater receiving part; and
In a state where the heater is inserted into the heater receiving portion, a sealing member for sealing both ends, respectively,
The rectangular heater accommodating portion is formed of a long side portion facing each other and a short side portion connecting the long side portion,
In order to induce deformation in which the interval of the short side portion is narrowed by the pressurization of the heater case, the defrost device, characterized in that bending grooves are formed on the left and right sides of the outer surface of the heater case toward the short side portion of the heater receiving portion, respectively. A refrigerator with According to claim 1,
The first heat pipe is disposed on the front side of the evaporator,
The second heat pipe is a refrigerator having a defrosting device, characterized in that disposed on the rear side of the evaporator. According to claim 2,
The heater case is disposed at a position lower than the lowest end of the cooling pipe of the evaporator,
The first and second inner passages extend long in the left and right directions of the evaporator,
A refrigerator having a defrosting device, characterized in that the first and second internal passages are disposed in the front and rear directions of the evaporator, corresponding to the first and second heat pipes respectively disposed on the front and rear surfaces of the evaporator. According to claim 1,
The first heat pipe forms a closed-loop circulation flow path together with the first inner flow path;
The refrigerator having a defrosting device, characterized in that the second heat pipe forms a closed loop circulation flow path together with the second inner flow path. delete According to claim 1,
The bending groove is formed on the upper and lower surfaces of the heater case to be recessed inward toward the heater accommodating portion so that the heater accommodating portion can be crushed in a predetermined shape when the heater case is pressed. A refrigerator with a defrost device. According to claim 6,
In the state where the heater case is pressed,
The upper and lower surfaces of the heater accommodating portion are bent inward around the bending groove,
The heater is a refrigerator having a defrosting device, characterized in that in close contact with the left inner surface and the right inner surface of the heater receiving portion. According to claim 6,
The bending groove is a refrigerator having a defrosting device, characterized in that formed extending along the longitudinal direction of the heater case. According to claim 6,
The bending groove is a refrigerator having a defrosting device, characterized in that formed at the midpoint of the heater accommodating portion. According to claim 6,
Refrigerator having a defrosting device, characterized in that the bending groove has a rounded shape. According to claim 1,
Grooves are repeatedly formed along the circumference of the first and second inner channels,
The groove is a refrigerator having a defrosting device, characterized in that extending along the longitudinal direction of the heater case. According to claim 11,
The first and second inner passages are divided into a first part and a second part based on a horizontal plane passing through the center and parallel to the heater,
The groove is a refrigerator having a defrosting device, characterized in that formed in a portion adjacent to the heater among the first and second portions. According to claim 2,
The heater case is disposed outside the support of the evaporator,
The first and second inner passages extend long in the vertical direction of the evaporator,
A refrigerator having a defrosting device, characterized in that the first and second internal passages are disposed in the front and rear directions of the evaporator, corresponding to the first and second heat pipes respectively disposed on the front and rear surfaces of the evaporator.

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