JPS61195579A - Planar heater - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a planar heater used as a heating source using electrical energy in equipment such as space heaters, cookers, and dryers. This invention relates to a planar heater in which an element is closely fixed with a heater coating layer.

Conventional technology In recent years, planar heaters have come into the spotlight as heating elements that meet the demands for thinner equipment and uniform heating. There is.

(1) A structure in which a heater is wound around an insulating substrate such as mica (2) A structure in which a conductive pattern is formed on an alumina substrate using a conductive paste such as tungsten, and then an alumina substrate is placed on top of the conductive pattern and integrally molded. (3) Those with a laminated structure in which a conductive pattern is formed between organic films (silicone, polyimide, etc.) However, in the case of (1), in the case of these sheet heaters, the heated object Since the heater was not sealed, there were problems with moisture resistance.

In addition, in the case of feces), the strength of the electricity extraction part was weak and the heat capacity was large, so there was a problem that the rise time was long. Furthermore, in the case of (3), the heat resistance temperature is low and 17129
As shown in Japanese Patent No. 6, a planar heater using a hollow substrate has been proposed.

3B-7 The present inventors have further improved the planar heater using the hollow substrate described above, and have proposed a new planar heater using a heater element made of a smooth mesh metal foil. .

The planar heater proposed by the present inventors is provided with a heater coating layer made of hollow material on a hollow substrate, and in this heater coating layer, a heater element made of a smooth mesh metal foil body, It has a structure in which a part of the electricity extraction terminal plate connected to the heater element and coming from the metal foil is embedded.

Problems to be Solved by the Invention By the way, one of the characteristics required of a sheet heater is as follows.
It has voltage resistance characteristics. This withstand voltage is measured between the heater element and the metal substrate in the hollow substrate.

If the withstand voltage characteristics measured by the above method are poor, it is dangerous to touch it with your hands during energized use, and therefore the range of application as a heater is limited, which is not a very desirable phenomenon.

However, in conventional planar heaters that use heater elements made of smooth mesh metal foil, due to the maximum width of the current-carrying part of the heater element, the withstand voltage characteristics of the completed planar heater are significantly affected. The reality was that there were differences and problems.

An object of the present invention is to provide a planar heater with excellent withstand voltage characteristics by analyzing the above-mentioned phenomenon and applying the analysis results.

Means for Solving the Problems In order to solve the above problems, the present invention is designed to suppress the maximum width of the energized portion of the heater element made of a smooth mesh metal foil to 5 mm or less.

Function Generally, hollow substrates contain very fine air bubbles in the insulating hollow layer. During the heat treatment process in which the heater element and the electrical outlet terminal board are closely fixed on the hollow substrate with the heater coating layer, some of these bubbles escape into the atmosphere through the heater coating layer, but the rest Most of it remains inside the 5-P insulating hollow layer or the heater coating layer.

However, these remaining bubbles are very fine, so
It does not have a significant effect on withstand voltage characteristics.

However, depending on the maximum width of the current-carrying part of the heater element, it is difficult for small air bubbles that exist on the underside of the heater element to escape into the atmosphere. Large bubbles may remain and significantly reduce the withstand voltage characteristics.

It has been confirmed through various experiments that this tendency increases as the maximum width of the current-carrying part increases, and in particular, it increases significantly when the maximum width of the current-carrying part exceeds five fins.

The present invention was made based on the above experimental results, and by suppressing the maximum width of the current-carrying part of the heater element to 6 mm or less, air bubbles remaining inside the insulating hollow layer or heater coating layer after heat treatment can be reduced. In addition to suppressing the size of the gas, it is also smoothly released into the atmosphere to prevent deterioration of withstand voltage characteristics.

6-Bay Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

As shown in Table 1, an insulating hollow made of a highly insulating glass frit to which KF is added and does not contain substances that cause ion conduction such as Na2O, Ni2O, Li2O, P2O5 is attached to a metal substrate 1a made of a steel plate for hollow holes. A hollow substrate 1 having a layer 1b formed thereon was prepared.

Table 1 7 ・＼ A heater element 2 was prepared by spot welding an electrical outlet terminal plate 3 also made of 5US430 to a heater element 2 made of smooth mesh-like 5US430 shown in FIG. 2.

At this time, as shown in FIG. 3, the maximum width 2a of the current-carrying part of the heater element 2 is 1 m as shown in Table 2.
It was varied within the range of m-10 mm.

On the hollow substrate 1 prepared by the above method, a thin hollow slip made of glass frit having a slightly smaller working temperature and coefficient of thermal expansion than the glass frit used to form the insulating hollow layer 1b is placed. Each heater element 2 to which the electrical outlet terminal board 3 was connected was placed in a undried state, and a similar Boloslip was applied thereon.

After drying this, heat treatment is performed and the heater element 2 is embedded in the heater coating layer 4 made of the above-mentioned hollow material, thereby tightly fixing the heater element 2 onto the hollow substrate 1, as shown in FIG. It has the structure shown in
Each sheet heater with a maximum width 2a of the current-carrying part is 1o
Completed one by one.

The withstand voltage characteristics of each of the completed planar heaters were evaluated by measuring between the electrical outlet terminal plate 3 and the metal substrate 1a in the hollow substrate 1, and the average values for each of the 10 sheets are shown in Table 2. Indicated.

If you use heater element 2 whose diameter is 15 mm or less in Table 2,
The withstand voltage characteristics of the Page sheet heaters are all over 2000V, demonstrating excellent withstand voltage characteristics.

However, the withstand voltage characteristics of a planar heater using a heater element 2 in which the maximum width 2a of the current-carrying part exceeds 5 mm is 1.
This markedly decreased to less than 000 ■.

As described above, it is clear that the withstand voltage characteristics are significantly improved in the sheet heater of the present invention using the heater element 2 in which the maximum width 2a of the current-carrying portion is suppressed to 5 mm or less.

Effects of the Invention As is clear from the above description, according to the present invention, a heater coating layer is provided on the hollow substrate, and a smooth mesh is provided in the heater coating layer to suppress the maximum width of the current-carrying portion to 5ii or less. Since the heating element made of a shaped metal foil is embedded, it is possible to provide a planar heater with excellent withstand voltage characteristics.

1o page.

FIG. 3 is an enlarged top view of the main part of the heater element.

1...Hollow board, 1a...Metal board,
1b...Insulating hollow layer, 2...Heater element, 2a...Maximum width of current-carrying part of heater element, 4...Heater coating layer.

Claims (1)

[Claims] A heater coating layer is provided on the hollow substrate, and a heater element made of a smooth mesh metal foil whose maximum width of the current-carrying part is suppressed to 5 mm or less is embedded in the heater coating layer. A sheet heater.