JPH07249475A - Panel heater of sic - Google Patents

Abstract

PURPOSE:To provide a heat emitting sheet body which is effective when used where a uniform temp. distribution is required by fabricating each heat emitting body in a plate having a specific width and thickness from a SiC heat emitting substance, and laying them flat to be used as a panel. CONSTITUTION:Each flat heater element wire 1 is made from a SiC heat emitting substance so that the width is 50mm or below and the thickness is 10mm or below, and a plurality of such element wires 1 are laid flat to be used as a panel. If the width of the single piece of heater exceeds 50mm, crazing, cracking, etc., will be generated at the time of heating, and the lifetime remain short. Therefore, it is required to design the heater width below 50mm. The heater thickness should be made under 10mm so that the interaction between the heaters is less.

Description

Detailed Description of the Invention

[0001]

The present invention relates to S which can be used under high temperature.
It relates to an iC quality panel heater.

[0002]

2. Description of the Related Art A silicon carbide heating element used as a heat source of a resistance heating furnace is generally used in a rod shape.
When trying to heat from the side wall surface of the furnace in a long furnace, there is a problem that the terminal electrode portion cannot be outside the furnace unless it is a very long rod. The heating element with a bent terminal is a very effective method for heating from the side wall surface of the furnace, but because it is rod-shaped, the radiation of heat spreads in the circumferential direction, and a uniform heat is applied to the unheated object. There was a drawback that it was difficult to give radiation. On the other hand, as for the panel heater in which the heat radiation spreads in a plane shape, since the heater element wire itself is made of metal, it is not known that it will generate heat to a high temperature enough to be used as a heat source of a resistance heating furnace. In addition to the problem of heat quantity, the conventional panel heater in which a metal heater is embedded in ceramics requires replacement of all of the panels when the wire is broken, and the replacement cost is very high. As a typical example of the above, the basic structure of the panel heater is shown in FIG. This heating element is composed of a heater element wire 1, an end electrode section 2, and a panel element body 3. The SiC heating element is made of a SiC sintered body, but its thermal shock resistance is low, so if it is made into a planar shape, it will crack during heating. Further, due to the difficulty of processing and the inflexibility of molding, it is very difficult to make the shape shown in FIG. 4 as seen in the graphite sheet heater. For this reason, conventionally, it has been very difficult to produce a panel heater made of SiC.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a SiC-based panel heater that solves the above problems.

[0004]

The present invention is characterized in that a SiC heat generating element has plate-shaped heat generating portions and is arranged in a plane to be used as a panel. The panel heater obtained by the present invention generates heat in a plane and has a uniform distribution,
The heat radiation efficiency is high, and since it is a plate-shaped heating element, there is no cracking during heat generation. That is, according to the present invention, by reducing the plate width, there is no crack like a planar shape, and by arranging in a planar shape, surface heating can be performed. The size of the surface can be easily changed by increasing or decreasing the number of plates.
Also, for partial disconnection, there is a cost merit that it is not necessary to collectively replace the panel itself by replacing only that part.

[0005]

The present invention will be described with reference to the drawings. 1 shows a panel heater according to the present invention, FIG. 2 shows a single plate heater, FIG. 3 shows a conventional metal heater embedded type panel heater, and FIG. 4 shows a conventional graphite sheet heater. As shown in FIG. 1, in the present invention, the plate-like heaters arranged at appropriate intervals are arranged in the same plane to form a plane, and therefore, in the present invention, the plane-like heat radiation is compared with the conventional rod-like heater. I know what to do. Regarding the width of the single plate heater, if the width is 50 mm or more, cracks, cracks, etc. occur during heating, and reliability and life are short. Therefore, the width of the heater needs to be 50 mm or less. Also, when the thickness becomes thicker, the heat radiation from the surface in the thickness direction increases,
The amount of heat radiation between the heaters becomes larger than that of the radiation surface due to the interaction between the adjacent heaters. If the gap is widened to reduce interaction, the amount of heat radiation in the thickness direction surface will decrease, but since it is radiated perpendicularly to the radiation surface, the amount of heat radiated to the substantially non-heated object will decrease, and uniform heating will not be achieved. Will end up. Therefore, the thickness of the heater needs to be 10 mm or less so that the interaction between the heaters is reduced.

[0006]

EXAMPLES The present invention will be described in more detail based on examples. Table 1 shows the temperature measurement results of the test bodies of Examples 1 to 3 and Comparative Example 2.

Example 1 Heater width 20 mm, length 2
A panel heater having a heating surface of 250 × 250 mm was prepared by combining 10 plate heaters having a thickness of 50 mm and a thickness of 5 mm. The plate to be heated was placed in the furnace so as to be parallel to the surface of the panel heater, and when the temperature inside the furnace was maintained at 1000 ° C., the temperature at 9 points on the surface was measured. The heater could be held without cracking. The temperature measurement results are shown in Table 1. Summarized in.

Example 2 Heater width 50 mm, length 2
A panel heater having a heating surface of 300 × 250 mm was prepared by combining five plate heaters each having a thickness of 50 mm and a thickness of 5 mm. The plate to be heated was placed in the furnace so as to be parallel to the surface of the panel heater, and when the temperature inside the furnace was maintained at 1000 ° C., the temperature at 9 points on the surface was measured. No cracks occur in the heater,
I was able to hold. The temperature measurement results are shown in Table 1. Summarized in.

[Embodiment 3] Heater width 50 mm, length 2
A panel heater having a heating surface of 300 × 250 mm was prepared by combining five plate heaters each having a thickness of 50 mm and a thickness of 10 mm. The plate to be heated was placed in the furnace so as to be parallel to the surface of the panel heater, and when the temperature inside the furnace was maintained at 1000 ° C., the temperature at 9 points on the surface was measured. The heater could be held without cracking. The temperature measurement results are shown in Table 1. Summarized in.

Comparative Example 1 Heater width 60 mm, length 2
A panel heater having a heating surface of 300 × 250 mm was prepared by combining five plate heaters each having a thickness of 50 mm and a thickness of 5 mm. The plate to be heated was placed in the furnace so as to be parallel to the surface of the panel heater, and when the temperature inside the furnace was maintained at 1000 ° C., the temperature at 9 points on the surface was measured. The two heaters were cracked and could not be held.

Comparative Example 2 Heater width 50 mm, length 2
A panel heater having a heating surface of 300 × 250 mm was prepared by combining five plate heaters each having a thickness of 50 mm and a thickness of 12 mm. The plate to be heated was placed in the furnace so as to be parallel to the surface of the panel heater, and when the temperature inside the furnace was maintained at 1000 ° C., the temperature at 9 points on the surface was measured. The heater could be held without cracking. The temperature measurement results are shown in Table 1. Summarized in.

[0012]

[Table 1]

As can be seen from these results, it was found that the shapes within the scope of the present invention did not cause cracks or crevices and had a good temperature distribution. In addition, Table 1
The symbol R in the inside represents a temperature difference. Measurement positions 1 to 9 are shown in FIG.
It is the position of in.

[0014]

According to the present invention, it is possible to provide a panel heater which can perform planar heating uniformly at high temperature, has high heat radiation efficiency, and is free from cracks and cracks during heat generation. Therefore, the industrial effect is great.

[Brief description of drawings]

FIG. 1 is a SiC panel heater of the present invention.

FIG. 2 Si constituting the SiC panel heater of the present invention
It is a C plate heater.

FIG. 3 is a conventional panel heater.

FIG. 4 is a planar heater found in conventional graphite materials and the like.

[Explanation of symbols]

 1 Heater wire 2 End electrode 3 Panel body

Claims (1)

[Claims] 1. An SiC heating element having a plate-shaped heating portion having a width of 50 mm or less and a thickness of 10 mm or less, and arranged in a plane to be used as a panel.
iC quality panel heater.