JPS62110284A - Sheath heater molding material - 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 sheathed heater that is used as a heating source in a wide range of product fields such as general cooking utensils and heating equipment. The present invention relates to a sealing material for a sheathed heater used to seal both ends of a pipe.

Prior Art Conventional 7-Z heaters are simple, safe, and have excellent corrosion resistance, so they can be used in ovens, microwave ovens, rice cookers, and hot plates.

It is widely used as a heating source for cooking appliances such as electric stoves and heating appliances.

This sheathed heater generally consists of inserting a coiled heating wire with terminal bars at both ends into the center of a metal pipe, filling the metal pipe with electrically insulating powder made of magnesia powder, and then It is manufactured by sealing both ends with a sealing material for a sheathed heater, and then reducing the diameter by rolling.

Conventionally, pole paper has been mainly used as a sealing material for such a sheathed heater.

This material is extremely low-priced, can flexibly respond to shrinkage during rolling diameter reduction, is easily carbonized by solution treatment, and can be easily removed by air blowing, etc. It was for a reason.

Problems to be Solved by the Invention On the other hand, in the manufacturing process of sheathed heaters, not everything is subjected to solid solution treatment, and ultra-low carbon steel or aluminum is used as the metal pipe, and as electrical insulating powder,
In the case of using magnesia powder added with unicorn resin, the metal pipe hardly undergoes work hardening due to diameter reduction by rolling, so it may be sufficient to just treat the electrical insulating powder to make it water repellent.

However, when such water repellent treatment is performed at 200 to 300"C, the conventional sealing material for 7-Z heaters made of cardboard easily carbonizes, resulting in damage to the metal vibrator and heating wire. The electrical characteristics between the

Therefore, after the heat treatment, the carbonized sealing material for a sheathed heater is actually removed by a method such as air blowing, which is very troublesome.

The present invention solves these problems by producing seeds with improved moisture resistance that do not cause carbonization even when subjected to a water repellent heat treatment process at 200 to 300°C after diameter reduction. The object of the present invention is to provide a sealing material for a heater.

Means for Solving the Problems In order to solve the above problems, the present invention is constructed using inorganic fiber paper impregnated with silicone oil and containing at least alumina fiber or silica fiber as a main component.

The main component of cardboard, which has traditionally been used as a sealing material for sheathed heaters, is straw, and when water repellent treatment is carried out in the air at 200 to 300°C, it is not completely oxidized and undergoes carbonization. occurs, which adversely affects electrical characteristics.

However, since the sealing material for a sheathed heater of the present invention is composed of an inorganic material whose main component is at least alumina fiber or silica fiber, it is not easily carbonized under the heat treatment conditions described above.

Furthermore, even if a small amount of organic matter contained as a binder is carbonized, the organic matter content is significantly lower than that of cardboard, which is a conventional sealing material for sheathed heaters, so no significant deterioration in electrical properties is observed. 〇On the other hand, inorganic fiber paper whose main component is the above-mentioned fibers easily absorbs moisture, and after the heat treatment described above,
If left in a humid atmosphere, electrical characteristics will deteriorate. Therefore, in the present invention, the material is pre-impregnated with silicone oil to improve the moisture resistance after heat treatment.
The impregnated silicone oil has excellent heat resistance and does not deteriorate under the heat treatment conditions of the above-mentioned water repellent treatment at 200 to 300''C.

For these reasons, after rolling diameter reduction, 200~300°
It is possible to obtain a sealing material for a sheathed heater that does not cause carbonization even when subjected to the heat treatment step of the water repellent treatment of C and has excellent moisture resistance properties.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

A heating wire 2 made of a coiled nichrome wire with terminal rods 1 at both ends is prepared, this heating wire 2 is inserted into the center of a metal vibrator 3 made of ultra-low carbon steel, and magnesia added with Noricone resin is prepared. Electrical insulating powder 4 made of powder was filled.

After this filling is completed, the paper 7 of the present invention, which is made of inorganic fiber paper mainly composed of alumina fibers shown in FIGS. 1 and 2, prepared by impregnating silicone oil in advance,
It is sealed using sealing material 6 for Z-heater, and the diameter is reduced by rolling, and then water repellent treatment is performed at 250°C for 1 hour.
Six sheathed heaters shown in FIG. 3 were completed, and their sample numbers were 6 to 1 degrees.

On the other hand, for comparison, five sheathed heaters were completed in the same manner as above using a conventional sealing material for sheathed heaters made of cardboard, and the sample numbers were numbered 1 to 6.

In addition, after the heat treatment by water repellent treatment at 250'C for 1 hour, the sheathed heater sealing material 5 was not particularly removed by air blowing or the like for any of the sheathed heaters.

The electrical characteristics of each completed sheathed heater were measured at the initial stage of completion, and the results are shown in the table below. In addition, in order to evaluate the moisture resistance properties, the samples were placed in a constant temperature and humidity chamber at 40° C. and 95% relative humidity for two weeks, and the insulation resistance at this time was measured. The results are shown in the following table in the same manner as above.

(Left below) As is clear from the table, in the sheathed heaters of sample numbers 1 to 5 that used the conventional pole paper encapsulating material 5 for /-Z heaters, the withstand voltage at the initial stage of completion was 1ooov or less, and the insulation The resistance was less than 200 MΩ, and the actual size could not withstand actual use.

In addition, all moisture resistance properties are less than 1MΩ,
There was a problem.

However, the present invention, which is made of inorganic fiber paper mainly composed of alumina fibers impregnated with silicone oil,
The nose heaters of sample numbers 6 to 1o using the sealing material 6 for heaters had a withstand voltage of 2,600 V or more at the initial stage of completion, and an insulation resistance of 2,000 MΩ or more, showing very excellent electrical properties.

Furthermore, in terms of moisture resistance, all exhibited excellent insulation resistance of 2000 MΩ or more.

In this way, by using an inorganic fiber paper whose main component is alumina fiber impregnated with silicone oil as a sealing material for a sheathed heater, even if heat treatment is performed to make it water repellent after rolling and diameter reduction, In particular, it is not necessary to remove the sealing material for the sheathed heater, and as a result, the manufacturing process is simplified, and a sheathed heater having excellent electrical properties and moisture resistance properties can be obtained.

In one embodiment of the present invention, inorganic fiber paper containing alumina fiber as the main component was used, but the present invention is not limited thereto. It may be something you do.

Effects of the Invention As is clear from the above explanation, according to the present invention, since the inorganic fiber paper impregnated with silicone oil and containing at least slender alumina fibers or silica fibers as a main component is used, after the diameter is reduced by rolling, It is possible to provide a sealing material for a 7-Z heater that does not cause carbonization even when subjected to a heat treatment process for water repellency treatment at 200 to 300°C and has excellent moisture resistance properties.

[Brief explanation of drawings]

FIG. 1 is a front view of a sealing material for a heater that shows an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the sealing material for a heater.
FIG. 3 is a sectional view of a sheathed heater using the same sealing material. 6... Sealed heater sealing material.

Claims (1)

[Claims] A sealing material for a sheathed heater, characterized in that it is constructed using inorganic fiber paper impregnated with silicone oil and containing at least alumina fiber or silica fiber as a main component.