JPS5996691A - Resistance heating furnace - 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 The present invention relates to a resistance photothermal furnace, particularly a connecting terminal portion (hereinafter simply referred to as a terminal portion) that engages a heating element and an electrode in the heat-generating furnace.
This invention relates to a novel cooling mode.

Conventionally, there are many known high-temperature heating devices used for firing various industrial materials such as carbon fiber and ceramic materials, such as resistance heating furnaces, induction heating furnaces, arc furnaces, and plasma furnaces. Furnaces are the most widely used because they rely on relatively simple heating means.

A resistance photothermal furnace uses a current to pass through a resistance heating element installed in the furnace to generate Joule heat to sinter the object to be heated. Usually, a gas such as nitrogen or argon is used for high-temperature heating of 1500°C or higher. A resistance heating element made of graphite material is used under an inert gas atmosphere.

Therefore, whether the heating element is made of a relatively inexpensive material that can sufficiently perform its function as a 7 heating element without causing melting and bicomposition even in a high temperature range of 1500°C or higher, or on the other hand, graphite material is used. It is depleted due to premature evaporation or chemical reaction with trace amounts of oxygen in an inert gas atmosphere. At this time, apart from the case of a resistance heating element where the wear and tear of the graphite material can be predicted and designed from the beginning, if a graphite material is used for the terminal part that engages the heating element and the electrode, one end of the terminal part It was common practice to water-cool the That is, when the graphite member in or around the terminal is worn out, its fine powder adheres to the insulating member interposed between the terminal and the furnace body, resulting in poor insulation or
Furthermore, electrical conduction with the furnace wall may cause problems such as poor insulation. In particular, the loss of graphite material due to the above chemical reaction is 11
It is most activated at around 00°C, and when heated at a high temperature of 1500°C or higher, the terminal reaches exactly this activation temperature. For this reason, a water-cooling jacket is usually provided in the terminal portion to cool it to at least the activation temperature or lower.

However, in recent years, as the structure of the resistance heating element itself has become larger, the water cooling jacket portion has also become larger, making the terminal structure more complicated and also having the drawbacks of large energy loss.

The present invention has been made for the purpose of eliminating the above-mentioned drawbacks of resistance heating furnaces and providing a cooling mode with a simple terminal structure and low energy loss.The present invention has the structure to achieve this purpose. is as follows.

In a resistance heating furnace in which a resistance heating element and an electrode are engaged through a connecting terminal portion, and an insulating member is interposed between the terminal portion and the furnace body, the insulating member is inert to external noise and/or internal noise. A resistance heating furnace characterized by having a gas supply path.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is an assembled sectional view of a terminal of a resistance heating furnace showing an embodiment of the present invention, and FIG. 2 is a view taken along arrows z-z' in FIG.

A resistance heating element l is attached to the tip of the terminal part 2 in the resistance heating furnace, and an electrode 3 is attached to the other end.
Electric power supplied from a power source through a connection network line 4 is sent to a resistance heating element l.

Resistance heating elements are generally used because they have excellent durability and heat generation function at high temperatures, are easy to process and can be formed into rod-shaped or tubular structures, and are relatively inexpensive. A graphite material is used, and a graphite material is also used for the terminal portion 2 as well.

The furnace body is constructed of a heat insulating material 5 such as carbon powder, and is surrounded by a furnace wall (inner wall 6, terminal insertion hole wall 7, and terminal outer wall 8).

Now, the terminal part 2 in the furnace body is surrounded by an insulating member 9, and this is fitted into a sleeve (usually made of graphite material) 10. Sleeve 10 on the inside (portion in contact with insulating member 9)
A groove 11 is provided parallel to the axis of. As a result, the inert gas (usually nitrogen or argon) supplied from the inert gas supply path 13 opened in the terminal box 12 is passed through this groove 11.
It passes through the furnace and enters the furnace (not shown), where the terminal portion 2 and its surroundings are cooled.

The grooves 11 provided in the sleeve 10 here have one to a plurality of grooves, and the size thereof may be such that a sufficient amount of inert gas can be supplied to cool the terminal portion 2 and its surroundings.

Of course, this structure 11 is not necessarily provided on the sleeve 10, but may be provided on the outer circumferential portion and/or inner circumferential portion of the insulating member 9 itself. It is sufficient to supply inert gas (low temperature).

Furthermore, if the sleeve 10 is provided with protrusions 14 closer to the inside of the furnace than the insulating part 9 and over the entire inner circumference of the sleeve, graphite particles evaporated in the furnace will enter and adhere to the insulating member 9 side. can be prevented.

Further, at this time, it is desirable that the gap between the protrusion 14 and the terminal portion 2 be as narrow as possible without interfering with the supply of inert gas into the furnace and within a range where insulation is possible. As described above, the present invention provides a method for cooling the terminal section 2 and the surrounding graphite material in a resistance heating furnace by using an inert gas between the terminal section 2 and the furnace body (usually the IJ + bulb 10). An inert gas supply path is provided on the outside (the sleeve side may be used) and/or inside of the insulating member 9 provided, and such a cooling means suppresses the wear and tear of the surrounding graphite material, and This has an excellent effect in that operational troubles such as fine graphite powder caused by wear and tear sticking to insulating members and causing poor insulation or poor insulation are greatly reduced.

[Brief explanation of drawings]

FIG. 1 is an assembled cross-sectional view of a terminal of a resistance heating furnace showing an embodiment of the present invention, and FIG. 2 is a view along arrows zz' in FIG. 1. l... Resistance heating element 2... Terminal section 3... Electrode 6, 7.8......°. Furnace wall 9 --- Insulating member 10 Sleeve patent application Daito Corporation Toshiba Ceramics Corporation Figure 1/l Figure 2

Claims (2)

[Claims] (1) In a resistance photothermal furnace in which a resistance heating element and an electrode are engaged with each other through a connecting terminal part, and an insulating member is interposed between the terminal part and the furnace body, an outside view and/or an inside number of the insulating member is provided. A resistance photothermal furnace characterized in that an inert gas supply path is provided in the. (2) A resistance photothermal furnace according to claim (1), wherein the resistance heating element and the connecting terminal portion are made of graphite material.