JPS6396886A - Defrosting heater - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a defrosting heating element device used in a heat exchanger of a refrigerator-freezer. Conventional technology In general, heat exchangers for refrigerators and freezers are made by arranging multiple thin metal plate fins in parallel, passing through the refrigerant pipes at right angles, and then expanding the refrigerant pipes to mechanically connect the fins and the refrigerant pipes. It is obtained by fixing the refrigerant pipe, and further forming the refrigerant pipe in the part where the fins are not arranged into a meandering shape so that the arranged parts of the fins are straight and parallel to each other. The so-called multi-stage heat exchanger, in which the fin rows obtained in this way are separated and independent, is set in the cooling duct of a refrigerator-freezer, and the compressor circulates the refrigerant through the refrigerant pipes and cools the freezer compartment and refrigerator compartment. can be cooled by forced circulation of airflow through a heat exchanger. The return airflow from the freezer compartment or refrigerator compartment is mixed at the airflow inlet of the heat exchanger and passes through the heat exchanger, but the temperature of the return airflow from the freezer compartment is -20 to -15°C. Since the temperature of the return airflow from the refrigerator compartment is 5 to 8℃ and the humidity is high, a large amount of frost forms on the fins on the airflow inflow side of the heat exchanger and the surface (17) of the refrigerant pipes, and cooling operation is interrupted. If this continues, the fins will become clogged and the cooling efficiency will drop significantly. Because of these things. It is necessary to defrost the heating element regularly 2 to 6 times a day by attaching it to the heat exchanger. When defrosting is performed using a heating element, defrosting must be completed efficiently in a short period of time in order to prevent food stored in the freezer from deteriorating. Also,
Since refrigerator-freezers are used with continuous electricity for long periods of time, it is important to keep the power consumption of each heating element to the minimum necessary. Conventionally, this type of defrosting heating element device was developed by the Japanese Patent Publication No. 58-99.
This method has been proposed in Publication No. 11 and Japanese Patent Application Laid-Open No. 189273/1983. According to Japanese Patent Publication No. 58-9911, heater insertion notches are provided at opposing corners (16) of the fin rows of a multi-stage heat exchanger so that thermal contact is made between the insertion notches. Be sure to install a vibrator heater with a heater wire inserted into a metal pipe. Further, according to Japanese Patent Application Laid-Open No. 59-189273, U-shaped notch grooves are formed in a plurality of fins and side plates of a heat exchanger, and one heating element is a heating resistor having a positive temperature coefficient,
A planar heating element is provided with an outer covering material such as an aluminum plate with good thermal conductivity via an insulating layer, and this planar heating element is inserted into a notch so as to be perpendicular to the plurality of fins. It was installed. Problems to be Solved by the Invention However, the conventional defrosting heating element device has the following problems. It had the following drawbacks. In other words, the special public service of 1982-1999
This is because, in Publication No. 11, the pipe heaters are attached in a meandering manner to opposite corners (16) of the fins. It has the following drawbacks. (1) The non-contact part between the vibe heater and the fin is approximately 2
0%, it is necessary to defrost by raising the surface temperature of the vibrator heater, and as a result, the temperature inside the cooling duct increases too much, which takes extra time for the next cooling operation, and causes damage to the freezer compartment. Food tends to deteriorate. (2) Since the vibrator heater is shaped like a serpentine and is attached to the corner (16) of the fin, it is not possible to defrost finely in areas where there is a lot of frost and where there is less frost because the shape has a certain interval. . (3) During defrosting, unmelted frost falls below the heat exchanger, so it is necessary to install a gutter-like heater underneath to defrost again, making the structure complex and increasing costs. It gets expensive. Furthermore, according to Japanese Patent Application Laid-open No. 59-189273, the fins and side plates have a U-shaped cutout groove into which a planar heating element is inserted, which has secondary drawbacks. (1) When installed in a multi-stage heat exchanger, the gaps between each stage of the fin rows are narrow, and the sheet heating element corresponding to the gap does not have enough heat generation capacity to complete defrosting in a short time. Longer frost time or more defrost cycles. As a result, frozen foods deteriorate and power consumption increases. (The 21-sided heating element has the characteristic that the heat value increases as the temperature decreases, but the heat value is almost saturated in the temperature range of -30 to 0°C, so the fins on the airflow inflow side where there is a lot of charge It does not have enough heat generating capacity to defrost parts efficiently in a short period of time. (3) A separate heater is required to melt the droplets during defrosting, which complicates the structure and increases costs. The object of the invention is to provide a defrosting heating element device which eliminates the above-mentioned conventional drawbacks. In other words, the defrosting heating element device according to the present invention has a heat-fusible heating element in which a cord-shaped heating element is provided with a heat-fusible coating on the outermost part of the metal sheet. disposed in an appropriate shape on the thin body, and furthermore, the thin metal plate is integrally formed around the outer periphery of the cord-like heating element, and further a bent portion is formed with the thin metal plate on the inside; In the defrosting heating element device, which is attached to a heat exchanger having fins in which an appropriate number of defrosting heating elements are arranged, each of which is approximately U-shaped and has a mallet portion at the bend (16), The pitch density of the heat exchanger is divided into a densely arranged part and a coarsely arranged part, and the fins of the densely arranged part are arranged loosely with respect to the metal thin plate-like body. A heating element is arranged, and a cord-shaped heating element is arranged densely to the fins made of the coarsely arranged portions to the thin metal plate.Fins of the working heat exchanger A cord-shaped heating element is integrally formed on the fin, and a metal thin plate-shaped body with a bent part formed in a U-shape is fitted. The fins are arranged coarsely in the areas corresponding to the dense pitch density of the fins, and densely in the areas corresponding to the base of the fins.In the above example, the contact area with the fins is The fins and cord-shaped heating elements are carefully arranged to match the amount of frost, and have the function of re-defrosting electricity.Example The following two examples of the present invention will be described in detail according to Figure (17). Fig. 1 shows an embodiment of a defrosting heating element 20 used in the present invention, in which 1 is a cord-shaped heating element arranged in a meandering manner;
5 is a heat-adhesive coating provided on the outermost part of the cord-shaped heating element 1; 6 is a thin metal plate, such as aluminum foil, having a thickness of 0.03 to 0.1 mm and having good thermal conductivity; 7 is a heat-fusible thin body made of a material that is laminated in advance on the surface (17) of the metal thin plate-like body B and has a property of being welded to the heat-fusible covering 5 by thermocompression bonding; 8 is a meandering arrangement; After fixing the cord-shaped heating element 1 to the metallic thin plate-like body 6 using the heat-sealing thin body 7, pressure molding is performed from the metallic thin plate-like body 6 side to form the metallic thin plate-like body 6.
A heater unit 9 is formed by surrounding and integrating a cord-shaped heating element 1 and further bent into a substantially U-shape so that the metal thin plate-like body is inside, and 9 is a highly thermally conductive heater unit 8 which is integrally joined or temporarily fixed to the heater unit 8. Thickness [L03~2 tone diffusion holder like aluminum plate, 10 is cord-shaped heating element 1 and connector 1
1 is a lead wire connected at part 1, 12 is a bent part formed into a substantially U-shape so as to be parallel to the elongated linear convex part 1a of the cord-like heating element 1 arranged in a meandering manner, and 13 is a bent part. The shelf section formed by the curved section 12, 14 is a drain port provided on the shelf section 13 for discharging water generated by defrosting, and 15 is an airflow inlet for return airflow from the freezer and refrigerator compartments. The arrangement pitch density of the body 1 is such that the pitch density is denser on the substantially U-shaped bent portion 12 side and coarser on the opposite side that does not have the bent portion 12. FIG. 2 shows the heater unit 8 of the defrosting heating element 20, where 1 is a cord-shaped heating element, 2 is a core thread of the cord-shaped heating element made of heat-resistant fibers such as polyester or glass, and 3 4 is a heat-generating resistance wire made of metal wound around the outer circumference of the core thread 2; 4 is an insulating layer made of vinyl chloride, silicone rubber, etc., which is tubed by extrusion molding around the outer periphery of the core thread 2 and the heat-generating resistance wire 6; 5 is a heat-fusible covering made of an olefin composition, a thermoplastic elastomer, etc., which is taped around the outer periphery of the insulating layer 4 by extrusion molding. 6 has good thermal conductivity and extensibility, for example 0.06 to (11
+ ma soft metal thin plate-like body such as aluminum foil, 7 is a material that is laminated in advance with the metal thin plate-like body 6 by lamination processing and is welded to the heat-fusible coating 5 by thermocompression bonding, such as an olefin-based material. It is a heat-fusible thin body made of polyethylene, vinyl acetate, etc. The metal thin plate-like body 6 is placed on the cord-like heat-generating body 1 arranged meanderingly in a predetermined pattern so that the heat-fusible thin body 7 faces the cord-like heat-generating body 1 side. By thermocompression bonding for 1-10 seconds at a temperature of °C. The heat-fusible covering 5 and the heat-fusible thin body 7 are welded and pressure-molded to obtain a heater unit 8 in which the convex portions 1a are formed. FIG. 3 shows the defrosting heating element 20 of this embodiment assembled into the heat exchanger 16, where 17 is a fin. Reference numeral 18 denotes a refrigerant pipe which is perpendicular to the fins 17 and whose portion where the fins 17 are not provided is bent in a meandering manner. The metal thin plate body 6 and the diffusion holder 9 are integrally joined with the cord-shaped heating element 1 disposed in a meandering manner, and the bent portion 12 is formed into a substantially U-shape so that the metal thin plate body 6 is on the inside. A heating element for defrosting which is bent at a certain point is brought into contact with the fin 17, and the refrigerant 101
A diffusion holder 9 is fixed to a side plate 21 provided at the meandering portion of the 8. The surface 1a of the metal thin plate-like body B that surrounds and integrates the cord-shaped heating element 1 has multi-stage fins 17.
into the notches 19 provided at the corners of the fins 17 and on both sides (17) of the fins 17. The heat generated from the cord-shaped heating element 1 is thermally diffused between the thin metal plate 6 and the diffusion holder 9, making the temperature distribution almost uniform, and at the same time, the fins 1 in contact with the thin metal plate 6
It also diffuses into the cells 7 and exhibits its defrosting function. The shelf part 13 formed by bending into a substantially U-shape receives fallen frost and at the same time defrosts it again by the cord-shaped heating element 1 in that part and drains water from the drain port 14. Also, since the return airflow from the freezer and refrigerator compartments enters from the airflow inlet 15 and circulates through the heat exchanger 16 while being mixed, the portions located on the fins 17 where a large amount of frost forms on the airflow inflow side are The meandering arrangement pitch of the cord-shaped heating elements 1 is set close. FIG. 4 is a partially cutaway illustration of the defrosting heating element device of this embodiment, and 16 indicates fins 17 arranged at predetermined intervals.
The heat exchanger 20 is formed by making the refrigerant pipes 18 orthogonal to each other, cutting and bending the part where the fins 17 are not provided in a meandering shape, and then fixing it with a side plate 21. After forming a unit with a thin metal plate 6, bending it into a substantially U-shape, and providing a gas inlet 15 at the bend (16), diffusion holders 9 are placed on both sides (17) of the heat exchanger 16.
This is a heating element for defrosting that is installed by a. The fins 17 of the heat exchanger 16 have a fin pitch on the airflow inflow side (lower side in the figure). The fins are arranged so that the fin pitch on the opposite side is dense. The cord-shaped heating element 1 is arranged so that the fins 17 having densely arranged parts are arranged so as to be coarse with respect to the metal thin plate-like body 6, and the cord-like heating element 1 is arranged so that the fins 17 having densely arranged parts are arranged so as to be coarse with respect to the metal thin plate-like body 6. It is arranged so that it is close to the other. Next, the effects of the above configuration will be explained. A sheet-like heat generating system in which the cord-shaped heating element 1 is integrally joined with a metal thin plate-shaped body 6 having good thermal conductivity and a diffusion holder 9, and the metal thin plate-shaped body 6 surrounds and integrates the cord-shaped heating element 1. body and fins17. Since the arrangement pitch and arrangement shape of the cord-shaped heating element 1 correspond to each other coarsely and densely, heat can be extracted efficiently from the cord-shaped heating element 1, so even if high wattage heat is generated, the cord Heat aging of the heating element 1 does not cause the temperature of the 2-side surface of the enclosure to rise too much, thereby preventing an increase in convection loss. By attaching this defrosting heating element 20 to the heat exchanger 16, the side surface of the fin 17 comes into contact with the metal thin plate body 2, so that the heat conduction efficiency is good and the removal can be completed quickly. Therefore, the temperature rise inside the cooling duct can be minimized, so that the primary cooling operation can be performed smoothly and efficiently. Since the portion 1a is fitted into at least one of the corner portions or notches 19 of the fin 17, heating can be performed in accordance with the frost formation distribution of the heat exchanger 16, so that the heat exchanger 16 can be heated in accordance with the frost formation distribution, It is possible to save power without overheating the parts. The thin metal plate 6 is made of a soft and stretchable material, and if the diffusion holder 9 is about 0.1 mm or less, the thickness is approximately the same. However, there is no problem in bending it into a substantially U-shape.By bending it into a substantially U-shape, a mallet portion 13 can be formed, in which the cord-shaped heating element 1 is arranged and a drain port 14 is provided. heat exchanger 1
It is possible to receive the frost that has fallen from 6 and defrost it again. Furthermore, by providing the airflow inlet 15 at or near the shelf 13, the return airflow from the freezer compartment and the refrigerator compartment can be easily mixed in the space surrounded by the heat exchanger 16 and the shelf 13.9. The frost distribution on the fins 17 becomes more uniform, and the defrosting efficiency can be improved. Since these have a simple structure in which one sheet is bent into a U-shape, they can be manufactured at low cost. Further, since the cord-shaped heating element 1 is provided with the heat-fusible covering 5 on the outermost side, workability can be improved by forming the cord-shaped heating element 1 into a heater unit. The placement pattern can always be made accurately. Since it can improve the adhesion with the metal thin plate-like body 6 and the diffusion holder 9, it has the function of improving heat conduction characteristics. In the embodiment, an example was shown in which the insulating layer 4 and the heat-adhesive covering 5 were separate. The insulating layer 4 may be omitted if the heat-fusible covering 5 is made of a heat-fusible material having insulating properties, such as an olefin thermoplastic elastomer. In addition, the hardness of the heat-fusible covering 5 is determined to be 50 to 120 in terms of rubber hardness, in order to achieve good pressure molding when surrounding and integrating the thin metal plate 6 with the cord-shaped heating element 1. preferable. Note that the heat-fusible thin body 7 is laminated with the metal thin plate-like body 6 and has the property of being welded to the heat-fusible covering 5 and the diffusion holder 9 by thermocompression bonding. Although it is possible to rationally unitize and combine with the diffusion holder 9,
Other means For example, a heater unit consisting of a meandering cord-shaped heating element and a film made of the same material as the heat-fusible thin body 7 is prepared in advance, and this heater unit is combined with the metal thin plate body 6. It may also be integrally joined to the diffusion holder 9 by sandwiching it therebetween. Alternatively, the cord-shaped heating element 1 is sandwiched between two thin metal plates 6, and the metal thin plate 6 that becomes the inner side when bent into a substantially U-shape is press-molded to form the cord-shaped heating element. It is also possible to form a unit by integrally adhering to the periphery and provide the diffusion holder 9 on the outside of this unit. Furthermore, although the planar body is bent into a substantially U-shape, the purpose of the bending is to form a bridge portion 16, arrange a cord-shaped heating element, and re-defrost frost that has been struck by lightning. The shape to be bent may be approximately U-shaped or approximately V-shaped without any problem. Effects of the Invention The present invention has the following effects and has great industrial utility value. (1) The contact area between the cord-shaped heating element, metal thin plate, and fins is larger than that of conventional products, and defrosting can be completed in a short time, so there is no deterioration of frozen foods. Saves power. (21) Defrosting efficiency is high because heating can be performed according to the frost distribution. (3) Re-defrosting of lightning strikes from the heat exchanger can be done at low cost with a simple structure. 4.

[Brief explanation of Figure (17)] Figure 1 is a partially cutaway perspective view of an embodiment of the defrosting heating element used in the present invention, Figure 2 is a perspective view of a heater unit used in this embodiment, FIG. 3 and FIG. 4 respectively show a sectional view and a partially cutaway perspective view of the defrosting heating element device of this embodiment. 1... Cord-shaped heating element, 5... Heat-fusible covering. 6...Metallic thin plate body, 7...Heat-fusible thin body. 12...Bending portion, 16...Heat exchanger. 17...Fin, 20...Heating element for defrosting.

Claims (1)

[Claims] The cord-shaped heating element (1) provided with the heat-fusible coating (5) on the outermost part is attached to the heat-fusible thin body (7) provided on the metal thin plate-like body (6) into an appropriate shape. Moreover, the metal thin plate body (6) is integrally formed around the outer periphery of the cord-shaped heating element (1), and the bent portion (6) is formed with the metal thin plate body (6) inside. In a defrosting heating element device in which a defrosting heating element (20) having a substantially U-shape formed by forming a heat exchanger (16) having an appropriate number of fins (17), The arrangement pitch density of the fins (17) with respect to the heat exchanger (16) is divided into a dense arrangement part and a sparse arrangement part,
Cord-shaped heating elements (1), which are loosely arranged with respect to the metal thin plate-like body (6), are arranged on the fins (17) made up of the densely arranged parts, and Fin (1
7) A defrosting heating element device characterized in that a cord-shaped heating element (1) is closely arranged with respect to the metal thin plate-shaped body (6).