JPS60158587A - Sheathed 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] Industrial applications The present invention relates to a sheathed heater.

Conventional Structures and Problems Generally, the metal pipes of sheathed heaters are made of stainless steel alloys or nickel-chromium alloys, which have excellent heat and corrosion resistance.

However, at high temperatures where sheathed heaters are used, high-temperature corrosion occurs even when the metal pipe is used. Further, under severe conditions in the presence of corrosive gases, corrosion progresses faster. Eventually, if the metal pipe cracks or corrosion is severe, the pipe becomes perforated. When the inside of the pipe comes into contact with the outside 27 and the atmosphere in this way, the moisture in the atmosphere scum will be absorbed inside the pipe, causing a drop in the insulation resistance between the C1 metal pipe and the heating wire, resulting in a very dangerous situation such as electrical leakage. .

Therefore, in sheathed heaters, there is an urgent need for high-temperature corrosion protection of metal pipes.

Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned drawbacks of conventional sheathed heaters, prevent high temperature corrosion, and provide a sheathed heater with a long life by applying a surface treatment layer. .

Structure of the Invention The sheathed heater of the present invention has a 5iCi surface treatment layer applied to the outer surface of the metal pipe of the conventional sheathed heater, which significantly prevents high-temperature corrosion of the sheathed heater.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows a partial sectional view of a sheathed heater according to an uninvented embodiment. In Fig. 1, 1 is an Incoloy metal pipe, 2 is an organic paint coated with SiC powder coated on the outer surface of the Incoloy metal pipe 1, and 3 is a magnet 7 filled in the Incoloy metal pipe 1. 4 is a heating wire. The organic component of the organic paint layer 2 may be any organic component as long as the SiC powder is homogeneously dispersed throughout and coated uniformly. The sheathed heater heat treatment shown in FIG. 1 is carried out to completely burn off the organic components of the organic paint layer 2, thereby forming an acid SiC film on the outer surface of the Incoloy metal pipe 1.

The SiC film formed on the outer surface of the Incoloy metal pipe 1 protects the Incoloy metal pipe 1 and completely promotes warp and corrosion prevention.

FIG. 2 is a diagram showing the relationship between the energization time of the sheathed heater and the amount of corrosion. In these two figures, reference numerals B indicate those in which the surface treatment layer was applied using an organic paint containing JL-Sic powder, and the conventional one. In addition,
The temperature was controlled by the energizing voltage so that it was 800°C.

As is clear from Fig. 2, the amount of corrosion of the T1 Incoloy metal pipe with the surface treatment layer of the present invention applied to the outer surface of the T1 Incoloy metal pipe as time passes is smaller than that of the conventional sheathed heater. . This shows that the progress of corrosion was suppressed even though the surface treatment layer was formed.

Effects of the Invention As is clear from the above explanation, the present invention provides two advantages in high-temperature corrosion protection compared to conventional ones without a surface layer by coating the outer surface of the metal pipe of a sheathed heater with a surface treatment layer containing SiCf. It is effective in terms of

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing the structure of a sheathed heater according to an embodiment of the present invention, and FIG. 2 is a diagram showing the amount of corrosion of the sheathed heater with respect to the energization time. 1... Incoloy metal pipe, 2...S
Organic paint layer containing iC powder, 3... Insulating filler, 4
...Heating wire. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (1)

[Claims] A sheathed heater in which a surface treatment layer containing 5iCi is formed on the outer surface of a metal pipe containing an insulating filler and a coiled heating wire.