JPS61110988A - Far infrared 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 far-infrared heaters that are widely applied to heating, drying, cooking, and the like.

Conventional technology Conventional far-infrared heaters include: ■ Infrared lamps ■ Heat-generating elements embedded in ceramic and fired ■ Sheathed heaters with a far-infrared radiation layer formed on the surface ■ Ceramic tubes with heating wires inside There are also types in which electrically insulating powder is embedded, but from the viewpoint of radiation characteristics, mechanical strength, lifespan, etc., the sheathed heater described in (3) with a far-infrared radiation layer formed on the surface is often used.

In this type of far-infrared heater, the far-infrared radiation layer is mainly formed by a thermal spraying method.

Further, as far-infrared emitting materials, ZrO□, Z ro
2・5i02. Mixtures of several types of transition metal oxides such as TiO2 and At203, and composite oxides are mainly used.

However, the method of forming a far-infrared emitting layer by thermal spraying involves high manufacturing costs such as running costs. A method has been proposed for manufacturing far-infrared heaters by hollowing.

For example, a method in which a mixture of ZrO2/SiO2 and glass frit is hollow-treated to form a far-infrared emitting layer (
Japanese Patent Publication No. 58-190838) and a method of forming a radiation layer by enameling a mixture whose main components are ceramic and glass (Japanese Patent Publication No. 5B-38821) have been proposed. .

Problems to be Solved by the Invention However, although the far-infrared heater manufactured by the above method has relatively excellent emissivity in the far-infrared region, ■ 600
If it is used at high temperatures above 'C or exposed to water in such a temperature range, the far-infrared emitting layer will easily crack or peel.

■ The actual situation was that there were problems such as the overall white or black color and poor aesthetic sense.

Therefore, the present invention solves the above-mentioned two problems.
The objective is to provide a far-infrared heater that has a beautiful blue color and does not have a far-infrared radiation layer that cracks or peels even when used at a high temperature of 00°C or higher or when exposed to water in such a temperature range. .

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has provided a metal pipe whose main components are BaO and Sz02, and C.
A far-infrared emitting layer made of heat-resistant hollow material containing 5 to 30% aO by weight is provided.

Function In the present invention, a heat-resistant hollow material whose main components are BaO and Si02 is used as the far-infrared emitting layer, and this heat-resistant hollow material has excellent thermal shock resistance even when used at high temperatures of 600°C or higher. Therefore, even if exposed to water, it will not easily crack or peel. In addition, a heat-resistant hollow material whose main components are BaO and SiO2 has a weight ratio of 5
~30% of CaO contained has a high far-infrared emissivity,
It also has the effect of coloring the far-infrared radiation layer into a beautiful blue color.

For these reasons, it has a beautiful blue color and 600
It is possible to obtain a far-infrared heater that can be used at high temperatures of ℃ or higher.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

NCF300 was used as the metal pipe 1. On the other hand, a coiled Nichrome # (wire diameter 0.5
5 words) is prepared, inserted into the center of the metal pipe 1, and electrically insulating powder 4 made of fused magnesia powder is prepared.
was filled and rolled to reduce its diameter.

Thereafter, the surface of the metal pipe 1 was heat-treated at a temperature of 1100° C. for 10 minutes in order to form an oxide scale mainly composed of Cr2O5.

Note that the atmosphere at this time was a reducing gas containing Go and H2 as main components.

Subsequently, CaO was added to a glass frit mainly composed of BaO and SiO2 shown in Table 1, and clay, sodium nitrite, and water were added to each to prepare a slip.

Table 1 below shows the amount of CaO added at this time, as shown in Table 2, so that the amounts contained in the far-infrared emitting layer after firing were the same.

In addition, as shown in Table 2, the amount of CoO contained in the far-infrared emitting layer was varied in the range of 0% to 50% by weight.

Each of the slips prepared in the above manner is applied by a spray method to a metal pipe 1 on which oxide scale has been formed in advance, and baked at 1050°C for 5 minutes to form a long distance made of heat-resistant hollow hollow, as shown in Figure 1. An infrared emitting layer 6 was formed.

Finally, both ends of the metal pipe 1 were sealed with low-melting glass 6 and heat-resistant resin 7, and each far-infrared heater shown in Fig. 2 with a diameter of 11B and a length of 500ae was completed, and designated as sample numbers 1 to 8. . Note that the heater of sample number 1 was not particularly subjected to heat-resistant hollow treatment, and corresponded to a conventional sheathed heater.

The voltage was adjusted so that the surface temperature of the metal pipe 1 of each of the far-infrared heaters was SOO° C., and after the surface temperature was saturated, the far-infrared heater was placed in water, and the degree of peeling of the far-infrared radiation layer 5 was evaluated. The results are shown in Table 2.

In Table 2, ○ marks indicate that no peeling occurred, and X marks indicate that peeling occurred.

Table 2 also shows the color of each far-infrared heater when it is not energized. Furthermore, 2.6μm~30μr
We also measured the average emissivity in the wavelength range up to rL,
The same is shown in Table 2.

Table 2 As is clear from Table 2, Ic, CaO, BaO and 5
When 102 is added to the far-infrared emitting layer 7, which is mainly composed of This has the effect of suppressing peeling.

Furthermore, regarding the average emissivity from 2.5 μm to 30 μm, since CaO with excellent emissivity is added, Ca
It increases as the O content increases.

These trends were ideal when the CaO content was 5% to 30% by weight, that is, in the case of sample numbers 4, 5.6, and 7 of the far-infrared heater of the present invention.

As mentioned above, the far infrared heaters of sample numbers 1, 2, and 3, in which the content of CaO was 5% by weight or less, were black in color and had poor thermal shock resistance and average emissivity.

On the other hand, sample number 8 in which the content of COo is 30% by weight or more
With the far-infrared heater, the temperature was insufficient under the firing conditions of 1050° C., and it was impossible to form a uniform far-infrared radiation layer 5.

In addition, in the embodiment of the present invention, as the metal pipe 1,
Although NCF300 was used, the material is not particularly limited to this, and other heat-resistant steels such as 5LJS321 may be used.

In addition, although the glass frits shown in Table 1 were used as glass frits containing BaO and SiO2 as main components, they are not limited thereto.
Any material having t02 as the main component may be used.

Effects of the Invention As is clear from the above explanation, according to the present invention, the surface of the metal pipe contains BaO and Sio2 as main components,
In addition, it is equipped with a far-infrared emitting layer made of heat-resistant hollow material containing 5 to 30 inches of CaO by weight, so it will not emit far infrared rays even when used at high temperatures above COo℃ or even when exposed to water in such a temperature range. No cracks or peeling of infrared emitting layer,
Furthermore, it is possible to provide a far-infrared heater with a beautiful blue color.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of essential parts of a far-infrared heater showing an embodiment of the present invention, and FIG. 2 is a sectional view of the same heater. 1...Metal pipe, 5...Far-infrared radiation layer. Name of agent: Patent attorney Toshio Nakao and one other name
1 Figure 1---Ikkin Mulberry Bifu. 1-----Ichikin Leak Baigu

Claims (1)

[Claims] A far-infrared heater characterized in that a far-infrared radiation emitting layer made of a heat-resistant hollow material containing BaO and SiO_2 as main components and 5 to 30% by weight of CaO is provided on the surface of a metal pipe.