JP2712527B2 - Heating device for infrared radiation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat generating device for infrared radiation, and more particularly to a heat generating device for infrared radiation suitable for heating or heating a substance.

2. Description of the Related Art In recent years, infrared radiant energy has wide industrial applicability in heating or heating materials. Therefore, in order to effectively use such infrared radiation energy, various heat generating devices for infrared radiation have been proposed. For example,
When electric power is used as an energy source, silicon carbide having an emissivity close to 1 which is also used as a pseudo blackbody as a high-efficiency infrared radiator for high temperatures is conventionally used. Since the infrared radiation by the silicon carbide is a resistor, it is used as a primary infrared radiation heating device that emits infrared radiation energy when power is directly supplied.

However, the infrared radiator made of silicon carbide is oxidized when baked at high temperature in the air during the production process, and therefore, at the time of the production, the infrared radiator formed in a predetermined shape is made of silicon carbide in a non-oxidizing atmosphere. It is produced by firing ceramic particles at 2000 ° C. to 2300 ° C. to recrystallize the ceramic particles, and by crystal bonding between the ceramic particles. However, the calcination is performed at a high temperature in a non-oxidizing atmosphere, so that the calcination is difficult and costly. Further, since the infrared radiator made of silicon carbide is conductive, it has been necessary to perform an electrical insulation treatment such as providing an insulating material on the surface. Further, the infrared radiator made of silicon carbide had poor thermal shock resistance.

Therefore, high-efficiency infrared radiation energy radiation is not sufficient, but as an infrared radiator excellent in electrical insulation and thermal shock resistance, a thermal expansion coefficient of 2.0 × 10 ^-6 1 made of cordierite or aluminum titanate or the like is used. An infrared radiator obtained by adding a metal oxide to a low expansion ceramic particle having a temperature of / ° C or lower and heating it with a separately provided heating element, for example, a metal resistor such as a nichrome wire, is used to form the low expansion ceramic. A secondary infrared radiation heating device that emits infrared radiation energy from an infrared radiator is used. Explaining the composition of the infrared radiator, the low expansion ceramic is combined with a mixture of a crystal and a molten amorphous, and the metal oxide is present between the crystal and the amorphous, and a part thereof is the Solid solution in the crystal,
Further, a part thereof is solid-dissolved in an amorphous state to form an amorphous layer.

Problems to be Solved by the Invention However, in recent years, in a secondary infrared radiation heating device combining an infrared radiator as described above and a metal resistor for heating the infrared radiator, more efficient infrared radiation energy There is a demand for a heat generating device for infrared radiation having the following.

It is an object of the present invention to solve the above-described problem and to provide a heating device for infrared radiation that radiates highly efficient infrared radiation energy and has excellent electrical insulation and thermal shock resistance.

Means for Solving the Problems The heating device for infrared radiation of the present invention comprises an infrared radiator in which ceramic particles mainly composed of silicon carbide are bonded by a vitreous material, and a space is formed between the ceramic particles. The infrared radiation is emitted from the infrared radiation body by heating with a heating element.

The heating device for infrared radiation of the present invention has a porous body in which, as an infrared radiator, ceramic particles containing silicon carbide as a main component are bonded with a vitreous material, and a space is formed between the ceramic particles. Infrared radiators are used. Therefore, the infrared radiator can be fired into a predetermined shape at a temperature near the softening temperature of the vitreous material, so that its formation is facilitated, and the ceramic particles are formed more easily than a conventional silicon carbide resistor. Since it is bonded and separated by a vitreous material, it can be made to have electrical insulation properties, and it can absorb the thermal expansion of the ceramic particles in the space between the particles, so that it can withstand thermal shock Can be. Further, the porous infrared radiator can radiate infrared energy more efficiently than a conventional low-expansion ceramic infrared radiator made of cordierite or the like.

Embodiment Hereinafter, a heat generating device for infrared radiation according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a configuration example of an infrared radiator used for a heat generating device for infrared radiation according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes ceramic particles containing silicon carbide as a main component, around which a glass layer 2 made of a vitreous material having a softening point of 1500 ° C. or lower is formed, and the adjacent ceramic particles 1 are bonded. At the same time, a space 4 is formed between the ceramic particles 1 to form a porous body. A composition for producing the infrared radiator 3 configured as described above will be described.

The ceramic particles 1 containing silicon carbide as a main component as a raw material have an average particle diameter of 2 μm or more because the degree of oxidation increases when the average particle diameter is reduced and the infrared radiation characteristic of the infrared radiator 3 is deteriorated when firing. The one having a thickness of 200 μm or less is used in consideration of moldability. The glassy material of the glass layer 2 is 4% of K ₂ O and 3% of Li ₂ O as weight%.
%, Al ₂ O ₃ 19%, CaO 3%, SiO ₂ 66%, NaO 1
%, ₂ % of B ₂ O ₃ and 2% of MgO are weighed and mixed. Then, the weight ratio of the vitreous material to the ceramic particles 1 is set to 2: 8, and the organic binder is weighed and mixed, and then molded. Next, firing, as firing conditions,
The calcination time is shortened at 1500 ° C. or less in air. The reason is that, depending on the average particle size of the ceramic particles 1, the result of weight change and X-ray analysis has shown that the oxidation of the ceramic particles 1 is very small in a short period of time up to 1500 ° C. Therefore, the vitreous material used is prepared by adjusting the raw material so that the softening point is 1500 ° C. or less. The fired product obtained by this blending has physical properties affected by the average particle size of the ceramic particles 1, the glassy material of the glass layer 2, and the amount of the glassy material of the glass layer 2. Next, the average particle size is 35μm, 17μ
m, 5 μm, and 2 μm, each of which was mixed with the same component as the vitreous material of the glass layer 2 at the same weight ratio in each particle group of the ceramic particles 1 and heated at a temperature of 150 ° C./H. The bulk specific gravity and porosity (%) of each of the samples A, B, C, and D of each of the infrared radiators 3 which were heated to 1150 ° C. which is higher than the softening point temperature of the vitreous material and held for 2 hours and fired , Water absorption (%), bending strength (Kgf / m
Table 1 shows the measurement results of the physical properties of m ² ).

From the results in Table 1, it can be seen that each infrared radiator 3 is a porous body in which a space 4 is formed between ceramic particles 1. Further, in these infrared radiators 3, the thermal expansion of the ceramic particles 1 is relaxed in the space 4 in the event of a thermal shock, thereby preventing breakage between the ceramic particles 1 and having excellent impact resistance. I was able to. For sample A, the volume resistance at 20 ° C. was 10 ⁶ Ω · cm.
Thus, electrical insulation was enabled. Further, in order to obtain the infrared radiator 3 which is a porous body having the space 4 formed therein, considering the formation of the space 4 and the coupling between the ceramic particles 1, the weight ratio of the ceramic particles 1 to the vitreous material is 9: The ratio must be between 1 and 5: 5.

Next, a description will be given, with reference to FIG. 2, of a heating device for infrared radiation that combines the infrared radiator 3 and the metal resistor 5 as a heating element to obtain highly efficient radiation energy.

In the figure, an infrared radiator 3 is formed in a cylindrical shape, and a metal resistor 5 such as nichrome is inserted as a heating element into an inner diameter portion thereof. A configuration in which a voltage is applied to both ends of the metal resistor 5 to generate heat, and the infrared radiator 3 is heated by the thermal energy, whereby infrared radiant energy can be obtained from the infrared radiator 3. It has become.

Comparison of the measurement results of the radiation intensity of the infrared radiator 3 with the infrared radiation heating device configured as described above and the measurement results of the radiation intensity of the cordierite infrared radiation member used in the conventional infrared radiation heating device. Is shown in FIG.
As the measurement conditions of the radiation intensity in the figure, in a state where a constant area of the infrared radiator is kept at a constant temperature of 500 ° C. by heating the heating element, a constant time in each wavelength range obtained from the surface of the constant area. Is a comparative measurement of the degree of radiant energy. Comparing the present embodiment with the conventional one based on the measurement results, the radiant intensity curve 7 of the infrared radiator 3 of the present embodiment is higher than the radiant intensity curve 8 of the conventional infrared radiator made of cordierite. You can see that there is. Therefore, infrared radiation energy can be obtained with higher efficiency.

Further, since the thermal conductivity of silicon carbide itself is better than that of cordierite conventionally used, the ceramic particles 1 are bonded by vitreous material as shown in FIG.
Further, even in the case of the structure in which the space 4 is formed, it is possible to effectively use the structure with less energy loss.

In addition, K ₂ O, Li ₂ O, Al ₂ O ₃ , CaO, SiO ₂ , NaO, B ₂ O ₃ were used as the glassy material of the glass layer 2 described in FIG. A similar effect can be obtained by using a vitreous material having a softening point of 1500 ° C or less, including at least one of alkali metal oxides, alkaline earth metal oxides, phosphoric acid, fluoride, boric acid, etc. Can be.

Further, physical properties such as strength can be changed by selecting a vitreous material, so that it is possible to adjust the physical property values according to the purpose.

Effect of the Invention As described above, the heating device for infrared radiation of the present invention has a structure in which a glass layer made of a vitreous material is disposed on the surface of ceramic particles containing silicon carbide as a main component, and the ceramic particles adjacent to each other are bonded. In addition, by using a porous infrared radiator in which a space is formed between the ceramic particles, highly efficient infrared radiant energy having electrical insulation can be obtained. Further, an infrared radiator resistant to thermal shock could be obtained by the space. Furthermore, because of good heat conduction, an infrared radiator with less energy loss and high efficiency could be obtained. In addition, since firing in a non-oxidizing atmosphere at a high temperature is not necessary, cost reduction can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view schematically showing a main part of a heating device for infrared radiation according to one embodiment of the present invention, FIG. 2 is a cross-sectional view of the device, and FIG. It is an intensity curve figure. 1 ceramic particles, 2 glass layers, 3 infrared radiators, 4 spaces, 5 metal resistors.

Claims (4)

(57) [Claims] 1. An infrared radiator in which ceramic particles containing silicon carbide as a main component are bonded by a vitreous material and a space is formed between the ceramic particles, and an infrared radiator for emitting infrared light from the infrared radiator. A heat generator for infrared radiation, comprising: a heat generator for heating the infrared radiator. 2. An infrared radiation heating device according to claim 1, wherein said infrared radiator has an average particle diameter of ceramic particles containing silicon carbide as a main component of 2 μm to 200 μm. 3. The infrared radiator is a vitreous material containing at least one of an alkali metal oxide, an alkaline earth metal oxide, alumina, silica, phosphoric acid, fluoride, and boric acid having a softening point of 1500 ° C. or lower. 2. A heating device for infrared radiation according to claim 1, wherein the heating device is a material. 4. The infrared radiator has a weight ratio of ceramic particles mainly composed of silicon carbide to a vitreous material.
2. A device according to claim 1, wherein the ratio is between 9: 1 and 5: 5.