JPS6369181A - 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 Field of the Invention The present invention relates to a defrosting heating element 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 surfaces of the fins and refrigerant pipes on the airflow inflow side of the heat exchanger, and if cooling operation continues as it is, it will cause damage. This causes clogging between the fins and significantly reduces cooling efficiency. 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 the four heating elements to the minimum necessary.

Hitherto, this type of heating element has been proposed in Japanese Patent Publication No. 58-9911 and Japanese Patent Application Laid-Open No. 59-189273.

According to Japanese Patent Publication No. 58-9911, cuts for insertion of a heater are provided at opposite corners of a row of fins of a multi-stage heat exchanger, and a metal pipe is inserted between the cuts for insertion so as to be in thermal contact with each other. A pipe heater with a heater wire inserted inside was installed.

Further, according to Japanese Patent Application Laid-Open No. 59-189273, U-shaped notch grooves are formed in the plurality of fins and side plates of the heat exchanger, and the heating element 9 is a heating resistor having a positive temperature coefficient, and the outer A planar heating element is provided with an outer covering material such as an aluminum plate with good thermal conductivity through an insulating layer, and the planar heating element is installed by inserting it into a notch so as to be perpendicular to the plurality of fins. Ta.

Problems to be Solved by the Invention However, conventional defrosting heating elements have the following drawbacks. That is, in Japanese Patent Publication No. 58-9911, the pipe heater is attached in a meandering manner to the opposite corner portions of the fins, which has the first drawback.

(1) /: The contact area between the eve heater and the fins is small, and the non-contact area with the fins is about 20%.

This is because defrosting must be performed by raising the surface temperature of the pipe heater, and convection loss increases.

If the temperature inside the cooling duct is raised too much, the next cooling operation will take extra time, and the food in the freezer compartment will likely deteriorate.

(2) Since the pipe heater is formed in a serpentine shape and is attached to the corner of the fin, it is not possible to arrange it in a way that allows detailed defrosting of areas with a lot of frost and areas with a little frost, which results in longer defrosting time and power consumption. will increase.

(3) During defrosting, unmelted frost falls to the bottom of 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 structure has a primary drawback because it has a configuration in which a U-shaped cutout groove is provided in the fins and the side plate and a planar heating element is inserted therein.

(1) When installed in a multi-stage heat exchanger, the width of the two-sided heating element becomes too narrow due to the narrow gap between each stage of the fin row, making it difficult to generate enough heat to complete defrosting in a short time. Since the defrosting time becomes longer or the defrosting cycle has to be increased, the frozen food deteriorates and power consumption increases.

(2) The sheet heating element has the characteristic that the heat value increases as the temperature decreases, but in the temperature range of -30 to D℃, the heat value is almost saturated, so 9. There is not enough heat generation capacity to efficiently defrost the side fins in a short time.

(3) A separate gutter heater is required to melt the debris during defrosting, which complicates the structure and increases costs.

An object of the present invention is to provide a defrosting heating element that eliminates the above-mentioned conventional drawbacks.

Means for Solving the Problems The present invention has the following configuration in order to achieve the object. In other words, the defrosting heating element according to the present invention comprises a heat-fusible thin body in which a cord-like heating element is provided with a heat-fusible coating on the outermost part of the thin metal body, and a diffusion holder. from the approximately U-shape in which the metal thin plate-like body is integrally formed around the outer periphery of the cord-like heating element, and a bent part is formed with the metal thin plate-like body inside. Thus, the cord-like heating element is arranged closely on the side of the substantially U-shaped bent portion, and the opposite side, which does not have the bent portion, is arranged sparsely.

Function The defrosting heating element of the present invention has the above-mentioned structure.
It performs the following secondary functions. Namely.

By bending a planar heating element into a U-shape and setting it on both sides of the heat exchanger.

(1) Since the contact area with the fins is large and the surface temperature can be kept low, convection loss is small and efficient defrosting can be achieved.

(2) Cord-shaped heating elements can be precisely arranged to match the amount of frost formation.

(3) A cord-shaped heating element is installed using the U-shaped bent part as the machine part, so that it can be re-defrosted after dropping.

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

FIG. 1 shows an embodiment of nine defrosting heating elements of the present invention, in which 1 is a cord-shaped heating element arranged in a meandering manner, and 5 is a cord-shaped heating element provided at the outermost part of the cord-shaped heating element 1. heat-adhesive coating,
Reference numeral 6 denotes a metal thin plate-like body such as aluminum foil having a thickness of 0.03 to 0.1 m with good thermal conductivity, and 7 is a metal thin plate-like body that is laminated in advance on the surface of the metal thin plate-like body 6 and bonded to the covering body 5 by thermocompression. A heat-fusible thin body made of a material that can be welded; 8 is a heater unit obtained by fixing a meandering cord-shaped heating element 1 to a metal thin plate body B by a heat-fusible thin body 7; 9 is integrally joined to the heat-fusible thin body 7 after the thin metal body 6 of the heater unit 8 is pressure-formed from the side of the thin metal body 6 to surround and integrate the thin metal body 6 with the cord-shaped heating element 1. A diffusion holder such as an aluminum plate having a thickness of α06 to 0.5 with good thermal conductivity, 1
0 is the lead wire connected to the cord-shaped heating element 1 at the connector 10, and 12 is the length of the cord-shaped heating element 1, which has a meandering planar body in which the heater unit 8 and the diffusion holder 9 are integrally connected. A bent part formed into a substantially U-shape to be parallel to the linear convex part 1a, 13 is a part formed by the bent part 12, and 14 is water generated by defrosting provided in the part 13. 15 is an airflow inlet for the return airflow from the freezer and refrigerator compartments. The opposite side not having the portion 12 is arranged so as to be coarse.

FIG. 2 shows the heater unit 8 of the defrosting heating element, in which 1 is a cord-shaped heating element, 2 is a core string of the cord-shaped heating element made of heat-resistant fibers such as polyester or glass, and 6
4 is a heat generating resistance wire made of copper, nichrome, etc. wrapped around the outer circumference of the core thread 2, and 4 is made of vinyl chloride, silicone rubber, etc., which is extruded into tubing around the outer circumference of the core thread 2 and the heat generating resistance wire 3. The insulating layer 5 is a heat-fusible covering made of an olefin composition, such as polyethylene, vinyl acetate, thermoplastic elastomer, etc., which is tubed around the outer periphery of the insulating layer 4 by extrusion molding, and 6 is a heat-adhesive coating with good thermal conductivity and extensibility. A metal thin plate-like body such as a soft aluminum foil of 0.06 to 0.1st, for example, 7 is a material that is laminated in advance with the metal thin plate-like body 6 by lamination processing and has a property of being welded to the covering body 5 by thermocompression bonding, for example. olefin polyethylene,
It is a heat-fusible thin body made of vinyl acetate, etc. The thin metal plate 6 is placed on the cord-shaped heating element 1 arranged in a meandering manner in a predetermined pattern so that the heat-fusible thin body 7 faces the cord-shaped heating element 1 side, and heated to 120 to 250°C. By thermocompression bonding at a temperature of 1 to 10 seconds, the covering body 5 and the heat-fusible thin body 7 are welded together to obtain the heater unit 8.

Figure 3 shows a part of the cross section of the defrosting heating element.
5 is a heat-adhesive coating provided on the outermost part of the cord-shaped heating element 1; 6 is aluminum having a thickness of 0.03 to 0.1+mm with good thermal conductivity and stretchability. A thin metal body such as foil; 7 is a heat-sealable thin body laminated on the surface of the metal thin plate body B and welded to the covering body 5 by thermocompression bonding; is a diffusion holder made of aluminum or the like having a thickness of 0.06 to 0.5 trs and having good thermal conductivity, which is integrally joined to the metal thin plate 6 by a heat-sealing thin member 7.

In a step in which no heat is applied before the thin metal body 6 is integrally joined to the diffusion holder 9 by thermocompression bonding, a rubber foam is formed on the side of the thin metal body 6 with the cord-shaped heating element 1 side as a hard surface. By interposing an elastic body and applying a pressure of 50 to 300%, it is integrally enclosed around the outer periphery of the cord-shaped heating element 1. Also.

The thin metal plate 6 is soft and thinner than the diffusion holder 9, and is bent with the thin metal plate 6 facing inside.

FIG. 4 shows a state in which the defrosting heating element of the present invention is assembled into a heat exchanger 16, in which fins 17 are arranged at predetermined intervals, and 18 are orthogonal to the fins 17. It is a refrigerant pipe formed by bending the part that is not arranged in a meandering shape, and is integrally joined with a thin metal plate 6 and a diffusion holder 9 with a cord-shaped heating element 1 arranged in a meandering manner. A defrosting heat generating element is bent into a substantially U-shape at the bent portion 12 so that the shaped body 6 is on the inside, and is fixed in contact with the fins 17. The convex portions of the metal thin plate-like body B that integrally surrounds the cord-like heating element 1 are arranged at the corners of the multi-stage fins 17 and the notches 19 provided on both sides of the fins 17, The heat generated from the cord-shaped heating element 1 is thermally diffused between the metal thin plate body 6 and the diffusion holder 9, making the temperature distribution almost uniform, and at the same time, is also diffused to the fins 17 that are in contact with the metal thin plate body 6. As a result, it performs a defrosting function. Abbreviation U
The bridge part 13 formed by being bent into a letter 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.

Next, the operation of the above configuration will be explained.

It is a planar heating element in which a 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. Therefore, heat can be extracted efficiently from the cord-shaped heating element 1, so that even if a high wattage of heat is generated, the cord-shaped heating element 1 will not undergo thermal aging or the surface temperature will rise too much and convection loss will not increase. By attaching this heating element to the heat exchanger, the side surfaces of the fins 17 come into contact with the surface of the metal thin plate body B, so that heat conduction efficiency is high and defrosting can be completed quickly. Therefore, since the temperature rise in the cooling duct can be minimized, the ninth cooling operation can be carried out smoothly and efficiently.

Since the cord-shaped heating element 1 can be arranged in a meandering manner in accordance with the frost distribution of the heat exchanger 16, it is possible to save power without overheating the part that has been completely defrosted.

The metal thin plate-like body 6 is made of a soft and stretchable material, and includes a material having properties equivalent to metal, that is, a metallic thin plate-like body,
If the diffusion holder 9 has a thickness of about 0.1 rRM or less, there is no problem in bending it into a substantially U-shape even if the thickness is approximately the same. By bending it into a substantially U-shape, a bridge section 13 can be formed, in which the cord-shaped heating element 1 is arranged and a drain port 14 is provided to receive the frost that has fallen from the heat exchanger 16 and to re-defrost it. can do. Further, by providing the airflow inlet 15 at or near the bridge section 13, the return airflows from the freezer compartment and the refrigerator compartment are easily mixed in the space surrounded by the heat exchanger 16 and the bridge section 16.

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 a sheet of sheet is bent into a U-shape, manufacturing and assembly are easy.

Since the cord-shaped heating element 1 of the present invention is provided with the heat-fusible covering 5 on the outermost side, workability can be improved by forming the heater into a unit. You can always place the butter accurately.

It has characteristics such as improved adhesion with the metal thin plate-shaped body 6 and the diffusion holder 9, thereby improving heat conduction properties. In the embodiment, an example was shown in which the insulating layer 4 and the covering body 5 were separated, but 9
The present invention is not limited thereto, and the covering 5 may be made of an insulating, heat-adhesive material, such as an olefin-based thermoplastic elastomer. Further, the hardness of the cover body 5 is preferably 50 to 120 in terms of rubber hardness, from the viewpoint of ensuring good pressure molding when the thin metal body 6 is enclosed and integrated with the cord-shaped heat generating element 1.

The heat-fusible thin body 7 is laminated and bonded with the metal thin plate body 6 and has the property of being welded to the covering body 5 and the diffusion holder 9 by thermocompression bonding, so it can be used to form a heater unit or the diffusion holder 9. Although the joining operation can be performed rationally, the present invention is not limited to this.

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 created, and this heater unit is made up of the metal thin plate body 6 and the diffusion holder 9. They may be integrally joined by sandwiching them between them. In this case, before thermocompression bonding, it is necessary to apply pressure from the side of the metal thin plate 6 through an elastic body, and to perform molding such that the metal thin plate 6 surrounds and integrates the cord-shaped heating element 1.

In the present invention, the nine-sided body is bent into a substantially U-shape to form the bridge portion 16.
However, the purpose of the bending is to form the gutter section 16 and arrange the cord-shaped heating element to re-defrost the fallen frost, so the shape of the bend is approximately U-shaped or U-shaped. A substantially V-shape or the like is also acceptable.9 The present invention is not limited to a substantially U-shape.

Effects of the Invention The present invention has the following effects and has great industrial utility value.

(1) Defrosting can be completed in a short time with high wattage and low convection loss, so frozen foods do not deteriorate and power is saved.

(2) Defrosting efficiency is high because heating can be tailored to the frost distribution.

(8) Re-defrosting of debris from the heat exchanger can be done with a simple structure.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of an embodiment of the defrosting heating element of the present invention, Fig. 2 is a perspective view of a heater unit used in this embodiment, and Fig. 6 is a cross-section of the main part of this embodiment. FIG. 4 shows a schematic diagram of this embodiment attached to a heat exchanger. 1... Cord-shaped heating element, 5... Covering body. 6...Metallic thin plate body, 7...Heat-fusible thin body. 12...Bending portion, 9...Diffusion holder.

Claims (1)

[Claims] A heat-fusible thin body (7) in which a cord-shaped heating element (1) with a heat-fusible covering (5) provided on the outermost metal thin plate-like body (6) and a diffusion holder (9), and furthermore, the metal thin plate body (6) is integrally formed around the outer periphery of the cord-shaped heating element (1), and furthermore, the metal thin plate body (6)
) is formed into a substantially U-shape with a bent part (12) formed inside, and the substantially U-shaped bent part (12) side of the cord-shaped heating element (1) is closely arranged, and the Bent part (12
) A heating element for defrosting, characterized in that the opposite side without the heating element is arranged roughly.