JPS6115024A - Infrared radiation body - Google Patents

Abstract

PURPOSE:To increase the emissivity and heat resistance, also improve the instant hating capability by a method wherein a infrared radiation body is formed by a silicone carbide fiber woven textile, and a coating containing a metal oxide, a carbide and a notride is formed by utilizing the curing body made of a polyprosiloxane as the bonding agent. CONSTITUTION:The base body of an infrared rediation body is a silicone carbide fiber 3. A coating is formed on the fiber 3 surface, the coating containing more than one kind material is selected from the metal oxide 5 on which a curing body 4 made of a polyprosiloxane resin is utilized as a bonding agent, and selects from a group containing a carbide and a nitride. A silicon carbide fiber has a high absorbent coefficient such as 10-40mm.<-1> order level in an infrared rays whole wave length area. By providing said coating, the reducing of emissivity in the area of which wave length is more than 10mum level can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an infrared radiator that emits heat rays in infrared wavelengths by heating gas, electricity, oil, etc. belongs to. In particular, it relates to an infrared radiator used as a secondary radiator.

Conventional configuration and its problems Generally, infrared radiators are required to have the following properties.

■ High infrared emissivity. Desirably, it should be close to 1.

■ Excellent heat resistance when heated, especially heat resistance.

■ No cracking occurs when used under cold and hot cycles.

■ It must be easy and inexpensive to manufacture.

In particular, when heating gas, oil, etc. is used, the infrared radiator is made of a ceramic plate with many small holes formed in a honeycomb shape, from which premixed air and fuel are ejected and burned on the surface, producing red heat. There is a type of burner (in the case of gas, it is called a ``seapunk burner'').

However, because ceramic is molded through a complicated process,
In addition to being expensive, there is a problem that the range during which the combustion amount can be varied is narrow.

Furthermore, since it is made of ceramic, it has poor mechanical strength, is susceptible to heat shock, and has the disadvantage of cracking and pulverization.

On the other hand, it is common to use metal as the radiator and use it as a secondary radiator in the form of a wire mesh, lath mesh, punched metal, or the like in order to lower the heat capacity. A burner is used to heat this, which causes it to undergo secondary heating and become red hot, thereby emitting infrared rays. However, in this case, since it is a metal, the surface will oxidize, rust and deteriorate.
In addition to problems with durability, there is also the issue of poor radiation efficiency due to low infrared emissivity.

Purpose of the Invention The present invention has been made to eliminate the above-mentioned drawbacks of the conventional technology. The object of the present invention is to provide an infrared ray radiator that does not crack or powder, is resistant to mechanical impact, has excellent durability, and has good productivity.

Structure of the Invention In order to achieve this object, the present invention uses a cloth made of silicon carbide fiber as a base material, and coats polyboro 70 on it.
Using a cured product of xane resin as a binder, a coating containing one or more selected from the group of metal oxides, carbides, and nitrides is formed and used as an infrared radiator.

DESCRIPTION OF EMBODIMENTS As the silicon carbide fibers used in the present invention, for example, fibers produced by the method described in Japanese Patent Application No. 50-50529 may be used.

That is, dimethyldichlorosilane is dechlorinated and condensed with metallic sodium to synthesize polydimethylsilane, which is then thermally decomposed and condensed in an autoclave at 450 to 470 ℃ for more than 10 hours using polycarbosilane. , distillation is performed in an inert gas or vacuum to remove low molecular components and adjust the number average molecular weight of the polymer to about 1,500.

The polymer was then heated to 200-300% in an argon gas stream.
℃, and the thread coming out of the nozzle is wound onto a rotating drum at a speed of over 100 meters per second.

Next, the spun fibers are subjected to infusibility treatment and then fired at 1200 to 1300 in nitrogen gas or vacuum.

The silicon carbide fiber obtained in this way is β-
Consists of silicon carbide and carbon.

This silicon carbide fiber has heat resistance and has a heat resistance of 1100'c in air. Using this fiber,
Ropes and woven cloth items are made.

In the present invention, this silicon carbide fiber woven fabric is used. A type of FRM containing metal or the like can also be used in the same way. Silicon carbide fibers have high absorption coefficients on the order of 10-40 fflJ+' for the entire infrared wavelength range.

Furthermore, since the scattering coefficient is expected to be on the order of about 10 fi', the infrared radiation behavior consists only of surface reflection for the entire infrared wavelength range.

Therefore, the infrared radiation spectral characteristics are determined according to the wavelength dispersion of the refractive index. In the wavelength range of 10 μm or less, the refractive index is relatively high at 2.65, so surface reflection of about 20 cm is unavoidable, and the upper limit of the emissivity is about 0.8. Further, at a thickness of 10 μm or more, the refractive index rises, surface reflection increases, and the emissivity decreases. This is a disadvantageous characteristic because the absorption band of most foods is in this far-infrared wavelength region of 10 μm or more. To compensate for this, a coating containing one or more selected from the group of metal oxides, carbides, and nitrides is formed on a woven fabric made of silicon carbide fibers using a cured polyborosiloxane resin as a binder. .

The polyborosiloxane resin has, for example, a polymer having a structure such as C6H5C6H5 as its main component. This binder has the properties of a semi-inorganic polymer, and at room temperature it has properties similar to organic polymers, making it excellent in terms of operability when used in coatings, etc. When heated, the organic matter decomposes and sl , B10 is used as a skeleton to form a ceramic.

Complete ceramification is performed at 600'c. The coating on the woven fabric made of silicon carbide fibers is
Conducted at a film thickness of 30 μm. By incorporating a radiation material into the borosiloxane resin binder, wavelength selectivity can be imparted. This binder itself has a refractive index of about 1.5 in the entire infrared wavelength range, so
By applying this binder to the surface of the woven fabric, the surface reflection will be on the order of several inches, and a high emissivity of 0.9 or more can be achieved. However, if this binder is used alone, the heat resistance in a heat-resistant environment will be poor unless the film thickness is about 1 μm, so it is used as a filler by filling it with metal oxides, carbides, nitrides, etc. that have excellent heat resistance. This allows for better painting workability.
It can be used with a film thickness of ~30 μm.

These fillers include zirconia, titania, alumina, silicon carbide, silicon nitride, Fe, Mn, Cu, Ni
, Co, and other transition metal oxides, rare earth element oxides, and the like can be used. The blending ratio of these fillers to the cured polyborosiloxane resin is 1/1 by weight.
It is best to use a ratio of 1 or less, but if the aim is to provide wavelength selectivity with the filler, it is better to use a ratio of more than 2/1.

FIG. 1 shows a conceptual diagram of the infrared radiator of the present invention. The radiator is woven with 1 warp thread and 2 weft threads crossing each other. In this case, the aperture ratio is important. The opening ratio can be determined by the thread diameter d and the pitch t.

When used as a secondary radiator in a gas combustor, the aperture ratio is 5.
It is best to use it below 0.

FIG. 2 is a sectional view of FIG. 1. FIG. 3 is a partially enlarged view of the warp threads 1 in FIG. 2. In FIG. 3, the warp thread 1 is made by twisting a plurality of fibers with a diameter of about 13 to 15 μm, and on the surface thereof, a hardened polyborosiloxane resin 4 is used as a binder, and metal oxides 5, In addition, it contains fillers 6 such as carbides and nitrides.

Hereinafter, specific examples will be described.

As for the silicon carbide fiber base material, Nippon Carbon Co., Ltd.'s "Nicalon" (trade name) cloth was used.

Next, as a binder based on polyboronoloxane resin, "Inorganic Polymer:
Using SMP-32J, 100 parts by weight of the binder/dar, 10 parts by weight of ZrO2 and 10 parts by weight of Al2O3 were mixed with 100 parts by weight of toluene as a solvent to form a dispersion coating using a ball mill.

The SMP-32J cures and loses 2/3 of its weight.

8/jm on the “Nicalon” cloth using the spray method.
Coated at a film thickness of 300'C, 30 minutes, 700°C,
The coating was completed by baking for 30 minutes.

An infrared spectral radiation characteristic diagram of the infrared radiator thus obtained is shown in FIG.

In FIG. 4, 7 is the infrared spectral radiation characteristic in the case of the conventionally used A stainless steel base material, 8 in the case of only silicon carbide fiber, and 9 in the case of the radiator of the present invention.

As described above, it can be seen that the infrared radiator of the present invention exhibits an extremely high infrared emissivity.

Effect of the invention As described above, the infrared radiator of the present invention ■High infrared emissivity of 0.9 or more.

■ Because it is a fiber with low bulk density, it has a small heat capacity and excellent heat-up properties.

■ High heat resistance and can withstand continuous use in air up to 1000'C.

■ Due to its flexibility, it can be processed into various desired shapes and can be used in a wide variety of ways.

■ Excellent heat shock resistance and high durability.

■ Absorbs mechanical shock due to its elasticity.

■ Film formation can be applied by spraying, which provides excellent productivity.

It has the following effects.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the infrared radiator of the present invention, Fig. 2 is a sectional view of the radiator, Fig. 3 is an enlarged partial cross-sectional view of the radiator, and Fig. 4 is the infrared spectral radiation characteristics of the invention. It is a diagram. 3... Silicon carbide fiber, 4...
・Cured product of polyborosiloxane resin, 5.6...
・One or more types selected from the group of metal oxides, carbides, and nitrides. Name of agent: Patent attorney Toshio Nakao (and 1 other person) Figure 1 Figure 4 Wavelength (, x * 1

Claims (1)

[Claims] A coating containing one or more selected from the group of metal oxides, carbides, and nitrides is formed on a woven fabric made of silicon carbide fibers as a base, using a cured polyborosiloxane resin as a binder. An infrared emitter.