JPS61277186A - Surface 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, dryers, etc., and particularly relates to a planar heater that is used as a heating source using electrical energy in equipment such as space heaters, cookers, and dryers. This relates to a planar heater that is closely fixed.

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 have been various planar heaters on the market as shown below. There is.

(1) One that has 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 provided on top of the conductive pattern and integrally molded.

(3) It has a laminated structure in which a conductive pattern is formed between organic films (silicone, polyimide, etc.).

However, in the case of (1) among these planar heaters, the heat transfer to the object to be heated is poor, and the heater is not sealed, so there is a problem in moisture resistance. Also (2
In the case of ), the strength of the electrical output and the heating part was weak and the heat capacity was large, so there was a problem that it took a long time to start up. Furthermore, in the case of (3), the heat resistance temperature was low and there was a problem with the life characteristics.

Therefore, in order to solve the above problem,
As shown in Japanese Patent No. 1296, a planar heater using a hollow substrate has been proposed.

Furthermore, 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.

As shown in FIG. 5, the planar heater proposed by the present inventors has a heater coating layer 2 made of hollow material provided on a hollow substrate 1 in which an insulating hollow layer 11L is formed on a metal substrate 1b. A heater element 3 made of a smooth mesh-like metal foil body and a part of an electrical output terminal plate 4 made of a metal foil body and connected to the heater element 3 are embedded in the heater coating layer 2. It has a similar structure.

Problems to be Solved by the Invention However, in the above configuration, when increasing power consumption and using a planar heater at a higher temperature, cracks or cracks may occur in the insulating hollow layer 11 of the hollow substrate 1 or the heater coating layer 2. There was a problem in that peeling occurred and the film could no longer be used in actual use.

For these reasons, the current situation is to keep the operating temperature low, and a planar heater that can be used at higher temperatures is desired.

The present invention solves these problems and aims to provide a planar heater that can be used at higher temperatures.Means for Solving the ProblemsTo solve the above problems. According to the present invention, a heater element made of a smooth mesh metal foil is provided on a hollow substrate, and a heater coating layer formed by a thermal spraying method is provided on the heater element. .

Operation In a conventional planar heater, the heater element is closely fixed by a heater coating layer made of hollow material. In such a structure, if the operating temperature becomes high, the insulation will deteriorate due to the difference in thermal expansion between the insulating hollow layer of the hollow substrate and the heater coating layer, as well as warping or twisting of the metal substrate due to uneven temperature distribution. Cracks and peeling occurred in the hollow layer and heater coating layer.

However, the heater coating layer of the present invention is thermally sprayed, and then the heater element 12 to which the electrical extraction terminal plate 13 is connected is placed on the hollow substrate 11 prepared by the above method.
An oxide mainly composed of aluminum oxide is sprayed thereon by a plasma spraying method, and the heater element 12 is closely fixed to the hollow substrate 11, and the heater coating layer 1
4, and ten planar heaters of the present invention having the structure shown in FIG. 1 were completed.

For comparison, a slip made of hollow material was applied thinly on the hollow substrate 1 prepared by the above method, and the heater element 3 to which the electrical outlet terminal plate 4 was connected was placed in an undried state. Furthermore, a slip made of the same hollow material was applied on top of it.

After drying this, heat treatment is performed, and the heater element 3 is embedded in the heater coating layer 2 made of hollow material, thereby tightly fixing the heater element 3 on the hollow substrate 1, as shown in FIG. Similarly, the sheet heater of 10
Completed.

Then, the voltage was adjusted so that the surface temperature of the side without heater elements 3 and 12 of each completed sheet heater was 260'C, and an intermittent energization test was conducted in which one cycle was 20 minutes of energization and 10 minutes of rest. The process was repeated 1000 times, and the insulating hollow layer 1a at this time.

112L and the heater coating layers 2 and 14 were examined for the occurrence of cracks and peeling, and the results are shown in Table 2.

Table 2 As is clear from Table 2, cracks or peeling were observed in 6 out of 10 of the conventional products in which the heater coating layer 2 was formed using a conventional hollow material, but the heater coating formed by the thermal spraying method None of the products of the present invention consisting of layer 14 had cracks or peeling.

In this way, by providing the heater coating layer 14 formed by thermal spraying as the heater coating layer, it becomes possible to use the device at a higher temperature.

In the embodiments of the present invention, no particular pre-treatment for thermal spraying was performed, but the insulating hollow layer of the hollow substrate may be subjected to pre-treatment such as a blast treatment. Alternatively, the heater coating layer may be formed by thermal spraying on the insulating hollow layer in advance, placing the heater element thereon, and performing rough thermal spraying.

Effects of the Invention As is clear from the above description, according to the present invention, a heater element made of a smooth mesh metal foil is provided on a hollow substrate, and on the heater element,
Since the heater coating layer is formed by thermal spraying, it is possible to provide a planar heater that can be used at higher temperatures.

[Brief explanation of the drawing]

Fig. 1 is a cutaway front view of a planar heater showing an embodiment of the present invention, Fig. 2 is a front view of a heater element in the planar heater, and Fig. 3 is a perspective view of an electrical outlet terminal plate in the planar heater. 4 is a front view showing a state in which an electrical outlet terminal plate is connected to a heater element, and FIG. 5 is a cutaway front view of a conventional planar heater. 11... Hollow substrate, 12... Heater element, 14... Heater coating layer. Name of agent: Patent attorney Toshio Nakao and one other person
--Hole Base 12-"

Claims (1)

[Claims] A planar heater characterized in that a heater element made of a smooth mesh metal foil is provided on a hollow substrate, and a heater coating layer formed by a thermal spraying method is provided on the heater element.