KR20100037193A - Defrost apparatus using heater of surface type - Google Patents

Abstract

PURPOSE: A defrosting device using a flat heater with a heating strip is provided to increase defrosting efficiency using a pair of flat heaters. CONSTITUTION: A defrosting device comprises a pair of front defrosting heater(30a) and rear defrosting heater(30b). The front defrosting heater and the rear defrosting heater are arranged on the front side and rear side of an evaporator to be contacted with a heat radiation fin. Each defrosting heater comprises a heating strip(33), a substrate(31) for heat transmission, a first insulation layer(32), and a second insulation layer(34). When a power source is applied to both ends of the heating strip, the heating strip radiates heat.

Description

   Defrost apparatus using heater of surface type

The present invention relates to a defrosting apparatus and relates to a defrosting apparatus using a planar heater having a strip-like planar heating element.

     In general, a refrigerator includes a main body partitioned into a freezer compartment and a refrigerating compartment, a door for rotating opening and closing the front openings of the freezer compartment and the refrigerating compartment, and a freezing device for cooling the inside of the freezer compartment and the refrigerating compartment.

The refrigeration apparatus includes a compressor for compressing a gaseous refrigerant at high temperature and high pressure, a condenser for condensing the gaseous refrigerant compressed from the compressor into a liquid state, a capillary tube for converting the liquefied refrigerant into a low temperature low pressure state, and a capillary tube. And an evaporator that vaporizes the refrigerant liquefied at low temperature and low pressure to absorb latent heat of evaporation to cool the surrounding air. The refrigerating apparatus may cool the inside of the freezing compartment and the refrigerating compartment by supplying cooled air around the evaporator to the inside of the freezing compartment and the refrigerating compartment using a blower.

Since the surface temperature of the evaporator provided in the refrigerator of the refrigerator is lower than the temperature in the refrigerator, moisture present in the air in the refrigerator attaches to the frost-shaped frost on the surface of the evaporator. In order to reduce the heat exchange capacity of the evaporator, the defrost cycle is operated by installing a defrost heater such as an electric heater to remove the frost formed on the evaporator.

When the defrost cycle is operated, the blower fan is turned off for the defrost and the defrost heater is turned on. Then, the surface temperature of the heater rises, and the heat generated from the heater is transferred to the radiating fins of the evaporator, and the temperature of the evaporator tube is also raised through the radiating fins at the same time to remove the frost formed on the evaporator. When the defrost is completed and the defrost cycle is stopped, the fan is turned on again and the heater is turned off. During this defrost cycle, defrosting should be performed within a range that the temperature of the refrigerator room hardly changes, and after completion of defrosting, the refrigerating performance deteriorated due to the defrosting cycle should be quickly recovered.

An example of a conventional defrosting apparatus including the components necessary for operating such a defrosting cycle is shown in FIG. 1.

Referring to FIG. 1, the inner back of the refrigerator 100 manufactured by General Electric Co., Ltd. is densely extended to surround the horizontal line of the tube 110 and the entire tube 110 that are bent in a zigzag shape in which a refrigerant flows in the refrigerating device. An evaporator 130 composed of a plurality of linear heat dissipation fins 120 is disposed.

The defroster of the refrigerator 100 includes a glass heater 140 installed at a lower end of the evaporator 130 to apply heat to a lower portion of the tube 110 surrounded by a linear heat dissipation fin 120. And the lower portion of the glass heater 140 has a defrost water discharge port for discharging the defrost water.

 The refrigerator 100 is installed on the inner back side of the refrigerator, and the tubes 110 at the bottom of the refrigerator 100 are disposed at wide intervals and are arranged close to each other at relatively equal intervals toward the upper portion. The lower tube 110 is disposed at a wide interval to provide a convection space to transfer the heat generated during defrosting to the upper portion of the glass heater 140 located at the bottom.

When the defrost cycle is operated, the glass heater 140 is heated to generate heat. At this time, the heat generated from the glass heater 140 moves upward through the convection space. The heat transferred to the upper portion is transferred by the heat dissipation fin 120 and the tube 110 of the evaporator 130 to raise the temperature of the evaporator 130 to dissolve and remove the frost attached to the heat dissipation fin 120 and the tube 110. do. At this time, the defrost water generated by melting the frost flows into the defrost drain pipe 141 under the glass heater 140 and is collected in the water support (not shown) through the defrost water outlet 142. Here, the glass heater 140 also serves to evaporate the defrost water and the frost lump collected in the defrost drain pipe 141.

The heat generated when the glass heater 140 is heated during the defrost cycle should be evenly transmitted to the entire evaporator 130 arranged in the upper portion, but the glass heater 140 is installed under the evaporator 130. There was a problem in that the generated heat is not properly transferred to the upper evaporator 130, the defrost defects on the upper side.

In addition, according to the defrosting action, the flake shaped defrosted piece separated from the upper evaporator descends to the lower side, and the evaporator tube 110 and the heat dissipation fins 120 are stacked and accumulated in the middle part of the densely arranged and completely defrosted. When the residual frost does not freeze when the refrigeration cycle is resumed there is a problem that the defrosting efficiency is lowered.

This is due to the position of the glass heater 140 is located below the evaporator 130. In addition, the glass heater 140 generates a high temperature by using a high-capacity heater of about 562 watts to condense heat to the top of the evaporator 130.

In addition, since the defrosting apparatus performs the defrosting in a convection manner, the defrosting efficiency is inferior and the frost on the upper side of the evaporator 130 may be removed only when the glass heater 140 having a high capacity is heated for a long time. As a result, each ice generated by the ice maker disposed inside the freezer located above the evaporator 130 is partially dissolved while the frost on the upper side of the evaporator 130 is removed. The problem is that the water on the surface freezes, causing each ice to stick together.

Furthermore, since the heat generated by the glass heater 140 located at the lower part of the evaporator 130 moves to the upper part due to the convection phenomenon, heat transfer is not effective at the lower part thereof, and defrost water and frost masses accumulated in the defrost drain pipe 141 are formed. There was also a problem that the evaporation was not properly evaporated and the defrost water outlet was blocked when the refrigeration cycle was resumed.

Accordingly, an object of the present invention is to replace the heater for defrosting with a surface heater to install in contact with the front and back of the evaporator to transfer the heat in the conduction method to perform the defrosting to increase the defrosting efficiency to perform effective defrosting even as a low capacity heater An object of the present invention is to provide a defrost apparatus using a surface heater.

In addition, another object of the present invention is to place the ice generated in the ice maker on the top of the evaporator by dissolving each other by placing it at the bottom of the evaporator by using a surface heater made of a thin metal strip of the film is a low temperature heat generation and fast temperature response. It is to provide a defrosting apparatus using a surface heater that can prevent the phenomenon.

Still another object of the present invention is to provide a defrosting apparatus using a surface heater that can prevent freezing from occurring in the defrosting drainage pipe located under the defrosting apparatus.

Defrosting apparatus according to the present invention for achieving the above object is implanted in the evaporator of the refrigerating device having a structure in which a plurality of linear heat radiation fins are formed tightly to surround the entire horizontal line in the tube bent in a zigzag shape flowing refrigerant. In the defrosting device for removing the defrosting, the defrosting device includes a pair of front and rear defrost heaters disposed to face each other to contact the radiating fins on the front and back of the bottom of the evaporator, the defrost heater, respectively, It consists of a plurality of strips obtained by slitting a thin plate, which generates heat when power is applied to both ends of the strip, and the plurality of strips are arranged in parallel at intervals, and both ends of adjacent strips are interconnected. The evaporation of the heat generated from the planar heating element and the strip-shaped planar heating element A heat transfer substrate for transferring toward the side, a first insulating layer for fixing and insulating the strip-shaped planar heating element to a heat transfer substrate, and a second for blocking heat transfer to the top of the strip-shaped planar heating element It characterized by including an insulating layer.

Defrosting apparatus according to another aspect of the present invention is to remove the frost formed on the evaporator of the refrigerating device having a structure in which a linear heat radiation fin is densely formed to surround the entire horizontal line in the tube bent in a zigzag shape flowing refrigerant. In the defrosting apparatus for the defrosting apparatus, the defrosting apparatus includes a front and rear defrost heaters disposed to face each other to contact the radiating fins on the lower front and rear surfaces of the evaporator, wherein the defrost heaters are each obtained by slitting a metal sheet. A strip-like planar heating element which is composed of a plurality of strips, which generates heat when power is applied to both ends of the strip, and is arranged in parallel with a plurality of strips, and opposite ends of each adjacent strip are interconnected; An insulating layer for covering the outer periphery of the planar heating element, and the strip type planar heating element To secure the insulating layer and the heat of the strip-like plane heater it characterized in that it includes a heat-conducting substrate for a for transmitting toward the evaporator.

       Preferably, the first and second insulating layers are any one of a thermosetting resin, a silicone varnish, a Teflon coating, and a plasma coating, and the second insulating layer is preferably formed thicker than the first insulating layer. The substrate is formed of any one of Al, Cu, Ag, and Au.

The substrate for heat transfer of the defrost heater is preferably installed in contact with the evaporator.

In addition, the front and rear defrost heater is preferably formed in a length corresponding to the lower quarter of the evaporator, it is preferably disposed in the lower quarter of the evaporator. In this case, the front and rear defrost heaters may be set to different lengths.

Further, at least one of the front and rear defrost heater is preferably extended to the defrost water discharge pipe. In this case, the rear defrost heater disposed on the back of the evaporator is preferably extended to the defrost water discharge pipe.

Therefore, the defrosting apparatus of the present invention provides an effect of increasing the defrosting efficiency by using a pair of planar heaters in contact with the bottom front / back of the evaporator, and also a pair of planar heaters have the characteristics of low temperature heat with low capacity Since the ice maker does not transfer high temperature heat, the ice melts and does not clump together.

In addition, the defrosting apparatus of the present invention, the surface heater is made of a thin film, the installation position is free, it can be extended to the defrost water discharge pipe in the lower portion can effectively evaporate the defrost water generated from the removed frost.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2A is a plan view illustrating a heater assembly using a strip type planar heating element applied to the present invention, and FIG. 2B is a cross-sectional view taken along the line IV-IV shown in FIG. 2A.

2A and 2B, the heater assembly 10a using the strip-shaped planar heating element applied to the present invention has a strip-shaped planar heating element 13 having first and second electrode terminals 15a and 15b at both ends thereof. And an insulating layer 17 surrounding the outer surface of the strip-shaped planar heating element 13.

The strip-shaped planar heating element 13 is formed in a predetermined pattern in which strips 13a to 13d are zigzag continuous by slitting a metal thin film having a predetermined thickness, and an outer side of the strip-shaped planar heating element 13 is provided with an insulating layer having moisture-proof, heat-resistant and electrical insulation functions. 17) is covered.

In this case, the strip-shaped planar heating element 13 is laminated in a state in which a plurality of patterned strips 13a-13c are arranged between the upper and lower insulating films and plated on the outer circumference of the strip-shaped planar heating element 13. The insulating layer 17 can be formed.

Both ends of the plurality of strips 13a-13c are connected in any one of a series connection, a parallel connection, and a combination of series and parallel connections so as to match the resistance value required for the heater assembly.

The strip-like planar heating element 13 is formed of a single metal thin plate such as Fe, Al, Cu, iron-based (Fe-X), iron chromium-based (Fe-Cr) metal thin plate, and Fe- (14-21%) Cr-. FeCrAl alloy sheets such as (2-10%) Al, Ni (77%-), Cr (19-21%) and Si (0.75-1.5%), or Ni (57%-), Cr (15-18) %), Si (0.75 to 1.5%) and Fe (nitrogen) may be made of any one material of the nichrome hot wire material, amorphous thin plate (ribbon).

Preferred alloying materials for the FeCrAl alloy sheet are pecaloy alloys (also known as KANTHAL ^™ wires) or Fe-20Cr-5Al-REM (rare earth metals) synthesized at a ratio of Fe-15Cr-5Al, where REM (Y, Hf , Zr) 1%) can be used.

In addition, the amorphous thin plate is made of an Fe-based or Co-based amorphous material, it is preferable because the Fe-based amorphous material is relatively inexpensive.

Fe-based amorphous material is, for example, Fe _100-uyzw R _u T _x Q _y B _z Si _w, where R is at least one of Ni and Co, T is Ti, Zr, Hf, V, Nb, Ta , At least one of Mo and W, Q is at least one of Cu, Ag, Au, Pd and Pt, u is 0-10, x is 1-5, y is 0-3, z is 5-12 And w is 8-18.

The Co-based amorphous material is, for example, Co _1-x1-x2 Fe _x1 M _x2 ) _x3 B _x4 , where M is one or more elements selected from Cr, Ni, Mo, and Mn, and x1, x2, and x3 are each In an amorphous alloy in which 0 ≦ x1 ≦ 0.10, 0 ≦ x2 ≦ 0.10, and 70 ≦ x3 ≦ 79, the composition ratio x4 of B is 11.0 ≦ x4 ≦ 13.0.

Among the strip-like planar heating element 13 materials, the most preferable material is Fe-15Cr-5Al or Fe-based amorphous material, and Fe-15Cr-5Al has a high temperature corrosion resistance by forming an Al ₂ O ₃ (alumina) insulating film on the surface when heat treatment is performed. It has the advantage of solving the oxidation problem of the iron-based material at low cost.

In addition, among the well-known high temperature hot wire materials, the NiCROTHAL ^TM (Ni: 80) of the NiCr hot wire is known to have a specific resistance of 1.09 Ωmm ² / m, and KANTHAL ^TM D has a specific resistance of 1.35 Ωmm ² / m. , Fe-based amorphous thin plate (ribbon) has a specific resistance of 1.3 ~ 1.4Ωmm ² / m similar to the above-mentioned KANTHAL ^TM wire, it can be seen that it has good characteristics as a hot wire material, and furthermore, because it is relatively cheaper than KANTHAL ^TM wire In the present invention, it is used as a strip-shaped planar heating element 13 material.

However, the strip-like planar heating element 13 material may be any metal or alloy material as long as the specific resistance value required for the properties of the hot wire material is not large and can be obtained inexpensively.

On the other hand, the above-mentioned amorphous thin plate (ribbon) is obtained by, for example, by spraying the molten alloy of the amorphous alloy on the cooling roll is rotated at high speed by the liquid quenching method to cool at a cooling rate of 10 ⁶ K / sec and peeled off It has a thickness of ˜50 μm and is manufactured in a width of 20 mm to 200 mm. In addition, the amorphous material generally has excellent material properties such as high strength, high corrosion resistance, high soft magnetic properties, and the Fe-based amorphous ribbon has an advantage that it can be purchased at about 1/2 cheaper than that of a conventional silicon heater.

As described above, since the strip-shaped planar heating element 13 of the present invention uses a metal sheet of 10 to 50 µm as a heater material, the strip-shaped planar heating element 13 has a surface area of 10 to 20 times or more as compared to other coil type heating wires having the same cross-sectional area, thereby providing the same electric power. When heat is generated by using, low temperature heat is generated in a large area, so it is suitable as a low temperature heating material. That is, since the strip-shaped planar heating element 13 is made of a thin metal plate, the heat density generated per 1 cm 2 is low, so that the amount of heat is also low.

As a result, the strip-shaped planar heating element 13 produced by processing a ribbon made of a thin plate is relatively thick in the outer circumference of the heating element in consideration of the excessive heat and / or high temperature heat generation as compared with the conventional coil-type hot wire made of nichrome wire. There is no need to form a heat resistant coating layer. Therefore, high heat transfer efficiency can be attained.

In addition, the strip-shaped planar heating element 13 does not require temperature control using a separate controller because the surface temperature of the heater does not rise to a high temperature of 600 to 800 ° C. like the sheath heater and does not exceed a maximum of 110 ° C.

On the other hand, since the planar heater material employed in the present invention is a thin metal plate, for example, the predetermined width, length, and area of the planar heater are determined according to the size of the evaporator, and when heat is generated at a predetermined temperature required for defrosting, In order to have a suitable resistance value, it is preferable to slit the wide ribbon into strips having an appropriate width to narrow the width and to form the entire length of the heating element so as to pattern the same resistance value required for the surface heater. For example, the strips 13a-13c used for the strip-shaped planar heating element 13 applied to the present invention may be slit to have a width of 1-2 mm at a thickness of 25 μm.

In this case, for example, when the heater capacity of 200W and the length and width of the surface heater is implemented in the form of a band consisting of about 1500mm, 50mm can be configured using a strip of about eight lines. In addition, when the planar heater is implemented as a rectangular plate as shown in FIGS. 5 and 6, the length is shortened and the width is increased, and the number of strips used therefor may be increased to 20, for example.

One end of each of the first and second electrode terminals 15a and 15b is connected to a power plug through power cables 16a and 16b, and the other end is spot welded or soldered to both ends of the strip-shaped planar heating element 13, respectively. , It is preferable to coat by insert molding method using an insulating film to seal the connecting portion.

In addition, a predetermined fuse (not shown) may be inserted between the other ends of the first and second electrode terminals 15a and 15b and both ends of the strip-shaped planar heating element 13 so that a disconnection occurs when an overcurrent flows due to a short. have. Such a fuse (not shown) may of course be used in place of the other connecting strips 13e, 13f connecting the strips 13a, 13b, 13c. Furthermore, in the strip type planar heating element 13 applied to the present invention, it is also possible to secure safety by using a thermostat to cut off the power when rising above the set temperature without using a special temperature control device.

A method of manufacturing the planar heater using the planar heating element described above will be described with reference to the process diagrams of FIGS. 3 and 4.

       3A to 3D are process drawings for explaining the planar heater according to the first embodiment applied to the defrosting apparatus of the present invention.

       Before manufacturing the planar heater, it is necessary to manufacture and prepare a strip type planar heating element. That is, the strip-like planar heating element is slit to narrow the width of the amorphous ribbon or the FeCrAl alloy sheet of thin film in a strip pattern having a width of 1 to 2 mm (13a to 13c in FIG. 2a) to have a set resistance value as described above. The total length of the heating element is formed long in a structure connected in series, and is molded and prepared in a pattern in which two electrode terminals are arranged on one side and the other side.

When the surface heating element is ready, the aluminum substrate 31 of FIG. 3A is prepared. Since the aluminum substrate 31 is for uniformly transferring the generated heat of the surface heater, the aluminum substrate 31 may be formed of one of Al, Cu, Ag, and Au or an alloy material thereof having excellent heat transfer characteristics. In this embodiment, aluminum is used. . In this case, an anodizing treatment may form an insulating film for preventing oxidation on the surface.

When the aluminum substrate 31 is ready, the first insulating layer 32 is coated, as shown in FIG. 3B. The first insulating layer 32 is formed on the aluminum substrate 31 by dipping coating or otherwise using an insulating adhesive such as silicon vanish. Since the silicone vanish has a strong adhesive force in the semi-cured state after application, it is used as an adhesive using this property. Here, the thickness of the first insulating layer 32 is preferably set according to the voltage environment in which the heater is used, and the thickness of 10 micrometers to 100 micrometers, most preferably 50 micrometers. This is because if the thickness of the first insulating layer is too thin, less than 10 micrometers, the problem of insulation occurs, and if it is too thick, more than 100 micrometers, the thermal conductivity is reduced.

When the coating of the first insulating layer 32 is completed on the aluminum substrate 31, the planar heating element 33 prepared above is disposed as shown in FIG. 3C. The planar heating element 33 may have the same material and shape and the same function as the planar heating element 33 described with reference to FIG. 2A.

When the planar heating element 33 is bonded to the upper part of the first insulating layer 32, the planar heating element 33 and the first planar layer are coated by coating the second insulating layer 34 on the upper part of the planar heating element 33. It is formed on the insulating layer 32.

Like the first insulating layer 32, the second insulating layer 34 is also bonded and fixed using an insulating adhesive such as silicon vanish. Here, the second insulating layer 34 is preferably coated with a thickness of 1 millimeter to 100 micrometers, more preferably 300 to 400 micrometers thick.

As the insulating material of the first and second insulating layers 32 and 34, synthetic resins having excellent heat resistance and electrical insulating property may be used in addition to the silicone varnishes disclosed. For example, polyethylene terephthalate (PET), polyethylene (PE), and PP ( Various electrical insulation film materials, such as polyimide obtained by superposing | polymerizing Polypropylene (TPA), terephthalic acid (TPA), and mono-ethylene glycol (MEG), or silicone, can be used.

In the above-described embodiment, the insulating layer is formed using the silicon varnish, but the insulating layer may be formed by Teflon coating or plasma coating. In the plasma coating, the coating may be performed using a nano-size inorganic paint or ceramic material. In this case, the outer surface of the strip type planar heating element 33 is coated by the first insulating layer 32 and the second insulating layer 34 to have moisture-proof, heat-resistant and electrical insulation functions. The thickness of the planar heater 30 finally produced in the first embodiment is, for example, 1.50 mm.

Here, when the surface heater 30 is used in the defrosting apparatus, the second insulating layer 34 is provided toward the wall side of the refrigerator and the aluminum substrate 31 is provided so as to be in contact with the evaporator. In this case, it is preferable that the second insulating layer 34 has a heat insulating function.

Therefore, the second insulating layer 34 is formed to be relatively thicker than the first insulating layer 32 so that heat generated from the planar heating element 33 is effectively conducted to the aluminum substrate 31 to defrost the evaporator. Can be.

4A to 4F are process drawings for explaining the planar heater according to the second embodiment applied to the defrosting apparatus of the present invention.

Before manufacturing the planar heater, it is necessary to manufacture and prepare a strip type planar heating element. That is, the strip-like planar heating element is slit to narrow the width of the amorphous ribbon or the FeCrAl alloy sheet of thin film in a strip pattern having a width of 1 to 2 mm (13a to 13c in FIG. 2a) to have a set resistance value as described above. The total length of the heating element is formed long in a structure connected in series, and is molded and prepared in a pattern in which two electrode terminals are arranged on one side and the other side.

When the planar heating element is ready, the first insulating layer 41 of FIG. 4A is prepared. At this time, the first insulating layer 41 prepares a thermosetting film, for example, a PET film. And, as shown in Figure 4b, the planar heating element 42 is disposed on the upper portion of the PET film as the first insulating layer 41. As illustrated in FIG. 4C, the PET film, which is the second insulating layer 43, is disposed on the first insulating layer 41 on which the planar heating element 42 is disposed. That is, the planar heating element 42 has a PET film, which is an insulating material, is disposed above and below. Referring to FIG. 4D, laminating is performed to coat the PET film up and down on the planar heating element 42. That is, it manufactures using the silicon roll A and B in which two heaters were built.

Overlapping PET films forming the first and second insulating layers 41 and 43, respectively, on the upper and lower sides of the planar heating element 42, for example, the silicon rolls A and B set at 100 to 200 degrees in the direction of the arrow. Passing the heater assembly 40 can be obtained. Preferably, the thickness of the heater assembly 40 is 0.30 mm.

Here, in the present embodiment, a PET film is used as the material of the insulating layers 41 and 43 coated on the outer surface of the strip-shaped planar heating element 42 to function as moisture-proof, heat-resistant, and electrical insulation. The remaining materials disclosed in the examples can also be used.

Synthetic resins used as the insulating layers 41 and 43 are generally relatively inexpensive and have excellent electrical insulation, thermal stability, and water resistance, and silicon also has excellent heat resistance, tensile strength, stretch rate, and wear resistance. Therefore, since the insulating layers 41 and 43 having the above characteristics are coated on the outer surface of the strip-shaped planar heating element 42, a short circuit does not occur even in an environment with high humidity, thereby ensuring safety.

  Thus, the planar heating element 42 coated with the PET film by the lamination method should be laminated on the heat transfer substrate in order to transfer heat uniformly. The substrate may be formed of one of Al, Cu, Ag, and Au or an alloy material thereof having excellent heat transfer characteristics, and aluminum is used in this embodiment. In this case, an anodizing treatment may form an insulating film for preventing oxidation on the surface. Referring to FIG. 4E, an adhesive 45 such as a silicon varnish is applied onto the aluminum substrate 44. As shown in FIG. 4F, the heater assembly 40 is bonded and fixed to the upper portion of the substrate 44 by the adhesive 45. Thus, the thickness of the planar heater finally prepared is 1.40 mm.

When the surface heater according to the above embodiments is installed in the defrosting device, the temperature rise time to the maximum rise temperature of the heater is short when starting the regeneration operation, and the operation time is restarted when the compressor is restarted after the regeneration operation is completed. This can minimize the return time to the refrigeration cycle. That is, as the defrosting operation is completed, the power of the defrosting heater is turned off and the compressor is operated to substantially shorten the cooling time when the temperature of the refrigerant pipe decreases to 0 ° C. That is, the temperature response of the heater is fast), the overall defrost cycle is shortened, there is an advantage that can be switched to the refrigeration cycle immediately after the completion of the defrost.

5 shows a real picture of the planar heater manufactured by the above-described embodiments.

Referring to FIG. 5, the planar heating elements are disposed at equal intervals to show a planar heater in a state coated with an insulating layer, and is an example manufactured to be used in a defrosting apparatus of a refrigerator.

Hereinafter, embodiments of the defrosting apparatus according to the present invention using the planar heater of FIG. 5 will be described with reference to FIGS. 6 to 10.

6 is a schematic side view of a defrost apparatus using a planar heater according to a first embodiment of the present invention.

Referring to FIG. 6, the side of the evaporator 130 is schematically illustrated toward the refrigerator installation wall. Then, a pair of front and rear surface heaters 30a and 30b having different lengths are disposed below the front and rear surfaces of the evaporator 130, respectively. In this case, the front and rear surface heaters 30a and 30b are preferably arranged in the lower quarter of the evaporator 130 and are set to have corresponding lengths.

The rear surface heater 30b on the side of the refrigerator installation wall extends to the defrost water discharge tube 150 at the lower side, and the front surface heater 30a on the refrigerator door side is positioned above the defrost water discharge tube 150. Approximately, the front surface heater 30a has a length of 100 mm, and the rear surface heater 30 has a length of 200 mm. Upper ends of the front and rear surface heaters 30a and 30b are set identically.

Referring to the partially enlarged cross-sectional view of Figure 6, the front and rear surface heaters (30a, 30b) is an aluminum substrate 31 is disposed on the contact surface with a plurality of heat dissipation fins 120 (see Fig. 1) and arranged close to face each other It is.

In this arrangement, the heat generated from the planar heating element 33 during the defrosting operation is conducted to the aluminum substrate 31 having excellent heat transfer characteristics through the first insulating layer 32 of the thin film, and then the image of the aluminum substrate 31 Conduction is carried out at a uniform temperature on the left and right bottom. Therefore, heat is conducted to the plurality of heat dissipation fins 120 (see FIG. 1) of the evaporator 130 through the aluminum substrate 31 having a uniform temperature, thereby achieving a uniform defrost.

In this case, since the second insulating layer 34 of the thick film surrounds the rear surface of the planar heating element 33 as compared to the first insulating layer 32 of the thin film, the second insulating layer 34 serves as a heat insulating layer. As a result, the heat generated from the planar heating element 33 during the defrosting operation is mainly conducted to the aluminum substrate 31 through the first insulating layer 32 of the thin film, so that the heat conduction efficiency is high, and through the wall of the refrigerator, Increasing the temperature can be minimized.

In addition, since the planar heater 30 is made of a plurality of heat dissipation fins 120 and a myriad of line contacts, the planar heater 30 smoothly transfers the heat generated from the planar heat generators 33 in a conductive manner, and the heat transmitted to the plurality of radiator fins 120. Is transmitted to the tubes 41 of the evaporator 40 as well as the plurality of heat radiation fins 120 to defrost the surface of the tubes 41.

Therefore, since the heat generated from the surface heater 33 is uniformly transmitted to the evaporator 130 without loss in the planar heating element 33, the defrosting efficiency may be improved to reduce power consumption.

The temperature of each part during the defrosting according to the first embodiment described above will be described with reference to Table 1 below.

The conventional example uses a glass heater having a heater capacity of 562 W as shown in FIG. 1, and the first embodiment uses the planar heater shown in FIGS. 3D and 5 having a heater capacity of 180 W. FIG.

Ice Maker Temperature Tube temperature Evaporator Upper Temperature Evaporator Central Temperature Defrost drainage pipe temperature Conventional example 11.8 -1.3 23.7 25.9 24.7 First embodiment 7.5 3.5 12.6 13.8 17.5

As shown in Table 1, in the conventional example of FIG. 1, since the defrost heater is disposed at the bottom of the evaporator to perform defrost in a convection manner, the temperature of the middle and the top of the evaporator is high, and as a result, the temperature of the ice maker is 11.8 degrees. Each generated ice may melt.

On the other hand, in the first embodiment of the present invention, even though low-temperature heat is generated by using a low-capacity heater of 1/3, heat is conducted to the evaporator by conduction by direct contact, so that defrosting of the evaporator is performed quickly. The temperature of the middle and top of the evaporator is relatively lower than 10 degrees compared with the conventional example, and as a result, the temperature of the ice maker is 7.5 degrees to prevent the problem of melting each generated ice.

That is, when the first embodiment of the present invention is applied as a defrosting device, it can be seen that 10 defrosting and freezing cycles are repeated in about 4 days, and the time for operating the surface heater of the defrosting cycle takes about 50 minutes. After the defrosting, the temperature of the evaporator drops to 0 degrees and reaches the bottom of the evaporator within 5 minutes, so that the fast freezing cycle can be resumed.

In addition, in the conventional evaporator, since the tube temperature is too low at -1.3 degrees, which is below zero, the frost on the surface of the tube does not melt, and water and frost melted and melted down from the top stick to the surface of the tube, resulting in a problem. In the invention, the temperature of the tube has a temperature of 3.5 degrees of image so that this problem does not occur.

Furthermore, in the present invention, the planar heater is disposed adjacent to the defrost drainage pipe, so that no problem arises in melting and evaporating the defrost water and agglomerate collected in the defrost drainage pipe.

As described above, although the temperature of each part of the evaporator and the tube shows a great difference, in the present invention, both the front and rear surface heaters are arranged in direct contact with the lower side, so that the lower side and the defrost drainage pipe of the evaporator are conductive. As the defrost is made, the middle and the upper side are defrosted by conduction and convection, so that the temperature difference between each portion is not great and the optimum defrost temperature can be applied to each portion.

In the following embodiments, the planar heater 30 is placed in front of and behind the evaporator 130, and is intended to show that it is possible to change the position, height, size, and the like.

7 is a schematic side view illustrating a defrosting apparatus using a planar heater according to a second embodiment of the present invention.

Referring to FIG. 7, the front and rear surface heaters 30a and 30b are disposed to face the front and rear of the evaporator 130, and the heights of the front and rear surface heaters 30a and 30b are different from each other as in the first embodiment. That is, it is an example in which the position of the front surface heater 30 is moved to the upper portion of the evaporator 130, and even with this installation structure, the same defrosting effect on the evaporator can be obtained.

       8 is a side schematic view for explaining a defrosting apparatus using a planar heater according to a third embodiment of the present invention.

       Referring to FIG. 8, the front and rear planar heaters 30a and 30b are disposed to face the front and rear of the evaporator 130 and planar heaters having the same length are used. That is, the front surface heater 30a on the refrigerator door side and the rear surface heater 30b on the refrigerator installation wall side both have a length of 200 mm. The third embodiment is an example in which the upper position of the front surface heater 30a on the refrigerator door side is disposed above the rear surface heater 30b.

       9 is a schematic side view for explaining a defrosting apparatus using a planar heater according to a fourth embodiment of the present invention.

       Referring to FIG. 9, the fourth embodiment is arranged to face the front and rear surface heaters 30a and 30b having the same length as opposed to the third embodiment, and the front surface heater 30a is disposed on the defrost water discharge pipe 150. Positioned to below, the rear surface heater (30b) is an example of the upper portion of the defrost water discharge pipe 150.

       10 is a schematic side view illustrating a defrosting apparatus using a planar heater according to a fifth embodiment of the present invention.

       Referring to FIG. 10, the front and rear surface heaters 30a and 30b having the same length are disposed to face each other, and both the front and rear surface heaters 30a and 30b are disposed at the same level as the upper portion of the defrost water discharge pipe 150. This is an example of placement.

       As shown in the above embodiments, the two front and rear surface heaters (30a, 30b) are placed in contact with the radiating fins of the evaporator 130 to face each other back and forth of the evaporator 130 and adjust the installation position or height Modifications such as adjustment are obvious to those skilled in the art and are not limited to the above-described embodiment.

1 is a real photograph for explaining a conventional defrosting apparatus,

Figure 2a is a plan view for explaining a heater assembly using a strip-shaped planar heating element applied to the present invention,

FIG. 2B is a cross-sectional view taken along line IV-IV shown in FIG. 2A;

       3A to 3D are process drawings for explaining a manufacturing process of the planar heater according to the first embodiment applied to the defrosting apparatus of the present invention;

4a to 4f is a process chart for explaining the manufacturing process of the planar heater according to the second embodiment applied to the defrosting apparatus of the present invention,

5 is a sample photograph of the surface heater of the first embodiment,

       6 is a side schematic view for explaining a defrosting apparatus using a planar heater according to a first embodiment of the present invention;

       7 is a side schematic view for explaining a defrosting apparatus using a planar heater according to a second embodiment of the present invention;

       8 is a side schematic view for explaining a defrosting apparatus using a planar heater according to a third embodiment of the present invention;

       9 is a side schematic view for explaining a defrosting apparatus using a planar heater according to a fourth embodiment of the present invention;

       10 is a side schematic view for explaining a defrosting apparatus using a planar heater according to a fifth embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

30,30a, 30b, 40: Planar heater 130: Evaporator

150: defrost drainage pipe

Claims (14)

In the defrosting device for removing frost formed on the evaporator of the refrigerating device having a structure in which a plurality of linear heat dissipation fins are densely formed to surround the entire horizontal line in a tube bent in a zigzag shape flowing refrigerant, The defrosting device includes a pair of front and rear defrost heaters disposed to face each other so as to contact the heat radiating fins on the lower front and rear surfaces of the evaporator. It consists of a plurality of strips obtained by slitting a metal thin plate, which generates heat when power is applied to both ends of the strip, and the plurality of strips are arranged in parallel at intervals, and both ends of adjacent strips are interconnected. Strip-shaped planar heating element, A heat transfer substrate for receiving heat generated from the strip-shaped plane heater and transferring the heat toward the evaporator; A first insulating layer for fixing and insulating said strip-shaped planar heating element to a heat transfer substrate; Defrosting apparatus comprising a second insulating layer for blocking heat transfer to the upper portion of the strip-like planar heating element. The defrosting apparatus of claim 1, wherein the first and second insulating layers are any one of a thermosetting resin, a silicone varnish, a teflon coating, and a plasma coating. The defrosting apparatus of claim 1, wherein the second insulating layer is formed thicker than the first insulating layer. The defrost apparatus according to claim 1, wherein the front and rear defrost heaters are disposed in the lower quarter section of the evaporator. The defrosting apparatus of claim 4, wherein the front and rear defrost heaters are set to different lengths. The defrosting apparatus according to claim 1, wherein at least one of the front and rear defrost heaters is extended to the defrost water discharge pipe. The defrost apparatus according to claim 6, wherein a rear defrost heater disposed on the rear surface of the evaporator extends to the defrost water discharge pipe. In the defrosting device for removing frost formed on the evaporator of the refrigerating device having a structure in which a linear heat dissipation fin is densely formed to surround the entire horizontal line in the tube bent in a zigzag shape flowing through the refrigerant, The defrosting device includes a front and rear defrost heaters disposed to face each other so as to contact the heat radiating fins on the lower front and rear surfaces of the evaporator.        It consists of a plurality of strips obtained by slitting a metal thin plate, which generates heat when power is applied to both ends of the strip, and the plurality of strips are arranged in parallel at intervals, and both ends of adjacent strips are interconnected. Strip-shaped planar heating element,        An insulating layer for covering the outer circumference of the strip type planar heating element; And a heat transfer substrate for transferring the heat of the strip-shaped planar heating element toward the evaporator by fixing an insulating layer covering the strip-shaped planar heating element.       The defrosting apparatus of claim 8, wherein the insulating layer fixed to the substrate is a thermosetting resin or a silicone varnish.       The defrosting apparatus of claim 8, wherein the substrate is formed of any one of Al, Cu, Ag, and Au. The defrost apparatus according to claim 8, wherein the heat transfer substrate of the defrost heater is installed in contact with an evaporator. The defrosting apparatus according to claim 8, wherein the insulating layer covering the strip-shaped planar heating element is coated by laminating. The defrost apparatus according to claim 8, wherein the rear defrost heater extends to a defrost water discharge pipe disposed at the bottom of the evaporator. 9. The defrosting apparatus according to claim 8, wherein the front and rear defrost heaters are formed in a length corresponding to the lower quarter section of the evaporator and are disposed in the lower quarter section of the evaporator.

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