JPS6086A - Method of producing far infrared ray 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 is used as a heat source for warmers, cookers, drying equipment, etc., and relates to a method for manufacturing a far-infrared heater that efficiently emits far-infrared rays. It is.

Structure of conventional examples and their problems Conventionally, far-infrared heaters that emit far-infrared rays are: (1) Infrared lamps (2) Heat-generating wires embedded in ceramics and fired (3)
) There are some types of sheathed heaters that have a far-infrared radiation layer formed on the surface, but from the viewpoint of radiation characteristics9 mechanical strength, lifespan, etc., many types with a far-infrared radiation layer formed on the surface of the sheathed heater are manufactured. There is.

Generally, as shown in Fig. 1, a sheathed heater is constructed by inserting a coiled heating wire 2 with terminal rods 1 at both ends into a metal pipe 3, and inserting an electrically insulating powder such as fused magnesia into this metal pipe 3. 4, and both ends of the metal pipe 3 are sealed with glass 6 or heat-exchanging resin 6 as required.

On the other hand, as a far-infrared heater, there is one in which a far-infrared radiation layer 7 is formed on the surface of a sheathed heater, as shown in FIG.

The far-infrared radiation layer 7 is made of zircon at 60% or more,
In addition, Fe2O3, Coo, Nip, Cr2O3,
Fired mixtures consisting of oxides such as MnO2 and clay added, or from the group of d:, element circumference + C11 group 2 elements, group 3 elements, composite compounds, and zirconium silicate. 30% by weight of selected composite oxide
Those containing the above are known.

However, when these are used at a temperature of 600°C or higher, the far-infrared emitting layer γ peels off or cracks occur, so the reality is that they cannot be used at a temperature of 500°C or higher.

Thermal spraying is mainly used as a method for forming the shredded far-infrared emitting layer 7, but thermal spraying requires expensive equipment (the initial cost is very high, especially the running cost of tTTi), so this method is not recommended. The reality is that far-infrared heaters manufactured in

OBJECTS OF THE INVENTION The present invention solves the conventional drawbacks and provides a method for manufacturing a far-infrared heater with a high emissivity in the far-infrared region and a low manufacturing cost that can be used in a high-temperature region of 500°C or higher. .

Structure of the Invention The present invention uses a nickel-plated metal pipe, fills the space between the plated metal pipe and the heating wire with electrical insulating powder, and heat-treats the metal pipe, similar to the conventional manufacturing method of a sheathed heater. This method forms a far-infrared radiation layer mainly composed of nickel oxide on the surface, which forms a coating mainly composed of nickel oxide with high emissivity, and oxidizes the nickel plating layer. In order to form a coating that adheres well to metal pipes, it has excellent adhesion to metal pipes, and no peeling phenomenon occurs.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 2 and 3. Note that the same members as in the conventional example are given the same reference numerals, and their explanations will be omitted.

A metal pipe made of N (iF 800) plated with nickel to a thickness of 10 μm was used as the metal pipe 11, and after inserting the heating wire 12, it was filled with an electrical insulator 13 according to the conventional manufacturing method of a sheathed heater. The diameter was reduced by rolling.

Thereafter, heat treatment was performed for 10 minutes in an oxidizing atmosphere at 1000'C to oxidize the nickel plating layer on the surface of the metal pipe 110 and transform it into a far-infrared radiation layer 14, completing the far-infrared heater shown in FIG.

If the heater is to be used in a high temperature range (approximately 800° C.), it is desirable to use N0F800 for the metal pipe 11 as described above.

On the other hand, for comparison, NCF without nickel plating
300 metal pipe 3 is filled and rolled to reduce its diameter in accordance with the conventional manufacturing process of sheathed heaters.

A sheathed heater was completed through an annealing process (reducing atmosphere 1060'Q for 15 minutes).

For these heaters, the pipe surface temperature is 750°C.
The emissivity at each wavelength was measured when the setting was made, and the results are shown in FIG. In FIG. 4, a shows a conventional sheathed heater, and b shows a far-infrared heater according to an embodiment of the present invention.

Also, the pipe temperature was set to 600'C, 700'Q, 800'C.
A peeling test was conducted on the coating on the surface of the pipe when electricity was applied, setting the temperature to 20 minutes on and 10 minutes off as one cycle, and the degree of peeling after 1,000 cycles is shown in the table.

In this table, a mark ◯ indicates that there was no peeling, and a mark x indicates that peeling occurred.

As is clear from this table and FIG. 4, the far-infrared heater according to the embodiment of the present invention has a higher emissivity at each wavelength than the conventional sheathed heater, and even when used at a high temperature of 800°C. It is possible to manufacture a far-infrared heater with extremely excellent characteristics without peeling.

In addition, as the metal pipe 11, a metal pipe made of nickel-plated 5US321 with a thickness of 5 μm is used,
After filling, rolling, and diameter reduction in the same manner as described above, heat treatment was performed in an oxidizing atmosphere at 960'O for 30 minutes to form the far-infrared emitting layer 14.
When the far-infrared heater obtained by forming the infrared ray heater was evaluated in the same manner as described above, it showed far-infrared characteristics similar to those shown in FIG. Further, the coating did not peel off up to 700'C, making it possible to manufacture a far-infrared heater with excellent characteristics.

As is clear from the above explanation, the manufacturing method of the far-infrared heater of the present invention only requires an additional step of nickel plating the metal pipe, and the other steps are almost the same as those for the sheath heater, and the manufacturing cost is low. It is cheap, has a high far-infrared emissivity, and even when used at high temperatures of over 500°C,
An excellent far-infrared heater without peeling can be manufactured.

In the embodiment of the present invention, the thickness of the nickel plating layer is 5 μm and 10 μm, and the material of the metal pipe 11 is NGF 8005US321.

Further, although an oxidizing atmosphere is used as the heat treatment atmosphere, the present invention is not particularly limited to this, and the far-infrared emitting layer 14 can be efficiently formed by heat treatment in a neutral atmosphere.

In particular, heat treatment may be performed by energizing the heater itself to generate heat.

Effects of the Invention The present invention uses a nickel-plated metal pipe,
A far-infrared radiation layer containing nickel oxide as the main component can be formed on the surface of the metal pipe by simply applying heat treatment after filling and rolling to reduce the diameter according to the conventional sheathed heater manufacturing method. Big and 600°C
The present invention provides a method for manufacturing a far-infrared heater that can be used in the above-mentioned high-temperature range and is inexpensive to manufacture.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional sheathed heater, Fig. 2 is a sectional view of a conventional far-infrared heater, Fig. 3 is a sectional view of a far-infrared heater in an embodiment of the present invention, and Fig. 4 is a sectional view of each heater. It is a graph showing emissivity versus wavelength. 11...Metal pipe, 12...Heating wire, 1
3...-electrical insulating powder, 14... far-infrared radiation layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3/4 Figure 4/36 lρ 3ρ 5ρ Liquid length (μ town

Claims (1)

[Claims] A method for manufacturing a far-infrared heater, in which a heating wire is placed in a nickel-plated metal knob, electrical insulation powder is filled between the metal knob and the heating wire, and then heat treatment is performed.