JPH0629083U - Structure of sheet heating element - Google Patents

Abstract

(57) [Abstract] [Purpose] Thin, light, can withstand external force, has good thermal energy efficiency, and has uniform temperature distribution characteristics, the shape of the heating element can be freely selected, and electrical characteristics The present invention relates to the structure of a planar heating element for the purpose of providing a heater that has good quality and low cost without variations in quality such as temperature characteristics. [Structure] The surface of an aluminum plate is a substrate on which an electrical insulating film is formed by an alumina oxidation treatment. The pattern of the resistor is photoengraved, and a paste-like electrothermal alloy is silk-screen printed on the aluminum substrate by the photoengraving and fired to form an electric heater. By energizing, the entire aluminum substrate functions as a sheet heating element.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This plan is a planar heating element characterized by an arbitrary heating element shape, high density and uniform or arbitrary temperature distribution characteristics, efficient heat conduction, low energy loss, thin and light weight, and rigidity that can resist external stress. It relates to the structure of.

[0002]

[Prior art]

 An electric heating alloy wire rod (generally nickel-chromium wire) is stretched over pottery, ceramic material, heat-resistant glass, etc., or a groove is formed so that the electric heating wire rod can be easily inserted to form a heater. Alternatively, the heater is formed by winding or tensioning a wire rod for electric heating on a mica plate. In particular, for mass production of small and lightweight heaters, there is also a product in which a sheet-like heating element is produced by a technology (thick film technology) in which a paste-like alloy for electric heating is silk-screen printed on a ceramic plate and baked in a baking furnace to form a heater.

[0003]

[Problems to be solved by the device]

 The currently commercialized heaters have the following unavoidable problems due to the material surface of the heating wires and heat insulating materials used and the structural restrictions caused by these materials. 1. The dimensions, especially the thickness, cannot be reduced. 2. The heat-resistant substrate that holds the heating wire is weak against shock, bending, and twisting and easily damaged. If it has sufficient rigidity, the thickness increases and the weight becomes heavy. 3. The temperature distribution does not become uniform, or conversely an arbitrary temperature distribution cannot be obtained. 4. Can't make spot heating or heating element to fit any shape. 5. It is difficult to automate the process of attaching and winding the heating wire. 6. Due to the material and shape of the heat-resistant substrate or insulator, thermal efficiency and heat conduction are poor and energy loss becomes large.

[0004]

[Means for Solving the Problems]

 An aluminum plate is electrolyzed to form an alumina oxide film on the surface to form a substrate 2 having an electrically insulating film. A sheet-shaped heating element that forms a thick-film resistor 1 for heating and forms an electric heater by silk-screen printing on an aluminum substrate 2 by photoengraving with a paste-shaped electrothermal alloy patterned in the shape of a heating element and firing. And The shape of the thick film resistor 1 for heat generation can be freely changed in accordance with the temperature distribution and temperature characteristics required for the sheet heating element, and the dimensional accuracy is high because of the photoengraving technology. The difference can be extremely small. For the purpose of protecting the thick film resistor 1 for heat generation, if the upper surface of the heat generation surface is covered with a heat resistant resin material such as heat-resistant glass, polymide or Teflon, or a mica plate to provide a heat insulating effect, a single-sided heat generating element from only the aluminum substrate surface Can be If the upper surface of the heating surface is covered with an aluminum plate 2 also having an alumina oxide insulating film, a thick film resistor 1 for heating is built-in to form a planar heating element that generates heat from both sides.

[0005]

[Work]

 The patterned thick film resistor for heat generation can be a resistor with a small cross-sectional area and a long effective length and has a large specific resistance.Because the pattern shape is precise, there is no individual difference and there is no variation in electrical resistance. Since the gap between the resistors is small, it is possible to construct a packaged heater so as to obtain a high density and uniform temperature distribution. The aluminum substrate has good thermal conductivity, low energy loss, and high efficiency, so it can be used as an electric heater with low power consumption. Since it has rigidity, it can withstand impact, bending, twisting, etc. even if the plate thickness is thin, so that the overall thickness can be made extremely thin, resulting in a lightweight and highly efficient sheet heating element. Furthermore, although some metal resistors are easily oxidized in a heat generation state in the atmosphere and cannot be used for a long time, in the present proposal, nitrogen or argon is used to eliminate oxygen when processed by the aluminum substrate and the cover. By sealing in an inert gas and suppressing the amount of residual oxygen, oxidative corrosion during long-term use can be minimized. Since the thick film resistor for heat generation is processed by photolithographic technology and silk screen printing, it can be made into a heater shape that is optimal for heating and maintaining a special shape, spot, pinpoint or limited zone. A direct heating type rice cooker can be produced by forming an alumina oxide film around the outer wall and bottom of the aluminum inner pot of an electric rice cooker, firing a thick film resistor for heat generation, and coating the outer periphery with a heat insulating material. In the same way, it is possible to transfer the technology to consumer cooking equipment such as boiling water kettles and frying pans.

[0006]

【Example】

 FIG. 1 shows an example in which a paste-like alloy for electric heating is screen-printed on an aluminum substrate on which an alumina oxide insulating film is formed and fired to form a thick film resistor for heating. FIG. 2 shows the configuration of a planar heating element in which a thick film resistor is sandwiched by another aluminum substrate and heat is generated from both sides of the aluminum substrate obtained by firing the heating thick film resistor. FIG. 3 is a sectional view showing the structure of a direct heating type inner pot of an electric rice cooker. Figure 4

4. An example in which a concave groove is formed in an aluminum substrate by etching the same pattern shape as the thick film resistor as described in [4].

[0007]

[Effect of device]

 Compared to other conventional products, it is a planar heating element characterized by extremely small variations in electrical and temperature characteristics, compactness, easy handling, safety, high thermal energy efficiency, and durability that is resistant to damage. It is able to meet the demands of all industries, industrial fields, and consumer fields.

[Brief description of drawings]

FIG. 1 is an example of a pattern of a thick film resistor for heat generation.

FIG. 2 is a planar heating element capable of generating heat from both sides by sandwiching the heating resistor pattern surface of the aluminum substrate on which the thick film resistor for heating is fired with another aluminum substrate (having an alumina oxide insulating film surface). Example of configuring.

FIG. 3 is a cross-sectional view showing a structure of an inner pot of a rice cooker of a direct heating type, in which a heating thick film resistor is fired on the outer periphery and the bottom of the inner pot of the electric rice cooker.

FIG. 4 is a view of an aluminum substrate in which the same concave surface pattern shape as that of the thick film resistor for heat generation is processed by etching and an alumina oxide insulating film is generated by electrolytic treatment, and then an alloy for electric heating can be screen-printed on the concave surface. One case.

[Explanation of sign]

1 Thick film resistor for heat generation completed by firing 2 Aluminum substrate with alumina oxide insulation film 3 Inner pot of electric rice cooker (outer periphery and bottom surface are treated with alumina oxide film) 4 Outer periphery of inner pot of electric rice cooker Thick film resistor for heat generation after screen printing on the bottom and bottom surface 5 Coating material for protection and heat insulation effect of thick film resistor for heat generation 6 Aluminum board surface has the same shape as the pattern of thick film resistor for heat generation Shows an example of etching processing on the concave surface

[Procedure amendment]

[Submission date] July 29, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

Claims (4)

[Scope of utility model registration request] 1. An exothermic material is produced by patterning a paste-like electrothermal alloy on an aluminum substrate on which an alumina oxide insulating film has been formed by electrolytically treating the surface in the shape of a heating element, followed by silk screen printing and firing. A structure of a planar heating element, characterized in that a thick film resistor is molded to form an electric heater. 2. A heat generating thick film resistor is formed by covering the surface of the heat generating thick film resistor having the structure according to claim 1 with a heat resistant resin material such as heat resistant glass, polymide or Teflon, or a mica plate for the purpose of heat insulation. A structure of a sheet heating element that protects and heat is generated only from the aluminum substrate surface and the opposite surface is blocked by a heat insulating material. 3. A heat generating thick film resistor electric device comprising a fired thick film resistor having the structure according to claim 1, and a fired thick film resistor further covered with another aluminum substrate whose surface is treated with an alumina oxide insulating film. Structure of sheet heating element with built-in heater to generate heat from both sides of two substrates. 4. An electric heater having the structure according to any one of claims 1, 2 and 3, wherein the aluminum substrate surface is etched to form the same concave pattern shape as that of the resistor, and an alumina oxide insulating film is formed by electrolytic treatment. A structure of a planar heating element in which a heating thick film resistor is embedded in a substrate and stabilized by screen-printing an electrothermal alloy on the concave surface.