JPS60208076A - 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 Field of Industrial Application The present invention relates to a sheathed heater that is widely used as a heating source for general home appliances, industrial electric furnaces, and the like.

Conventional Structure and Problems Sheathed heaters have been widely used as heating sources for general cooking appliances such as toaster ovens, microwave ovens, rice cookers, and hot plates, and currently as industrial electric furnaces.

This is because the sheathed heater is simple, has excellent electrical insulation, is safe, and has excellent corrosion resistance.

In a general pressure sheathed heater, a coiled heating wire with electrical outlet terminals at both ends is inserted into the center of a metal pipe, and this metal pipe is filled with electrical insulating powder made of fused Magnenoa powder. is sealed with low melting point glass and heat resistant resin.

A sheathed heater with such a structure has excellent electrical insulation between the metal pipe and the electrical outlet/output terminal, so
This type of sheathed heater is particularly used in products where safety is important.

These sheathed heaters are made of metal pipe material.
Use either material USs○4F5US321 or NGF800, and use 5US3 as an electrical outlet terminal.
04 on the other hand, 1. As the low melting point glass, a glass material having a linear expansion coefficient of 110 to 130 x 10-7/''C, which is matched to the metal pipe material and the electrical lead-out terminal material, is used.

However, during the manufacturing process of this type of sheathed heater, especially in the post-process after sealing the glass, or when assembling the sheathed heater into a product, loads are applied to the electrical power output terminals, causing damage and low voltage. Melting point glass can break and electrical insulation may be impaired, so a sealing material and a sealing structure with excellent mechanical strength are desired.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks and provides a sheathed heater having a sealed structure with excellent mechanical strength.

Structure of the Invention The present invention uses 5US430LX as an electrical outlet terminal.
As a glass sealing material for sealing the gap between the metal pipe and the electrical outlet terminal,
00~130X 1 o-',/"co low melting point glass is used, and mechanical strength is increased by matching the thermal expansion between the metal pipe, the electrical outlet terminal, and the low melting point glass. It is something that

DESCRIPTION OF EMBODIMENTS A specific embodiment of the present invention will be described with reference to FIGS. 1 and 2.

(Example) As the metal pipe 3, N c F 800 (trade name Incoloy 5OO) was used, and as the electrical outlet terminal 1,
SUS 304 or 5US430LX was used, and as the heating wire 2, a Nichrome wire of the first type was used.

The composition of each of the above materials is shown in Table 1.

The following margins and low melting point glass 5 have a linear expansion coefficient of 9° to 140.
The range of X 10′/”C was used.

The above-mentioned materials were combined as shown in Table 2, and a diameter of 6.6 mm as shown in FIG. 1 was obtained. Completed a sheathed heater with a length of 500m.

Hereafter, the sheathed heater is made by positioning a coiled heating wire 2 connected to an electricity extraction terminal 1 in the center of a metal pipe 3, filling the gap between the metal pipe 3 and the heating wire 2 with magnesia powder 4, and rolling it. After diameter, the metal pipe 3 was annealed and both ends of the metal pipe 3 were sealed with low melting glass 5.

On the other hand, the number of sheathed heaters in one combination is 10 each, and 1
The samples were numbered ~8.

Sample numbers 1 and 2 use the constituent materials of conventional sheathed heaters, and sample numbers 3 to 8 use 5US430LX as the electrical outlet terminal, and are made of low melting point glass with a linear expansion coefficient of 94 to 136 x 1o-'/ ft %).

In this way, the sealed structure of the completed sheathed heater (see Figure 2 i'+7 /11 j
-, 1. A load was applied to the sea urchin at a point 1011 m from the tip of the metal pipe, and then it was put into a water pressure tank. 3.5
The cracking of the low melting point glass was investigated by applying pressure at atmospheric pressure for one hour and then measuring the electrical insulation value between the metal pipe and the electrical outlet terminal.

At this time, the 7-Z heaters that showed a value of 2000 MΩ or more were considered to be good products, and the number of them is shown in the second column.

The load was between p=Q and 6Kp.

As is clear from Table 2, the limit is 1F = 2xp for one conventional seed plate of sample numbers 1 and 2, and if more load is applied, the glass will break and the air shielding will deteriorate. Ta.

On the other hand, sample numbers 3 to 8 using 5US4soLX terminals
Among them, the linear expansion coefficient of the glass material is 1o○x 1o'
/℃ or below or 130 x 10'/'C or above for the sheathed heaters of samples No. 3 and 8, after sealing (F=
Ox9) Glass cracks have already occurred in some cases, and glass cracks have occurred in cases 9 at F=2 to 4 even in cases where the glass was successfully sealed without any glass cracks.

However, the coefficient of linear expansion of the glass material is 100 to 130
Sample number 4,6°6 in the range of 1 o-'/”c.
In each of the ten sheathed heaters of the present invention, no glass cracking occurred even when a load of F = 6 kg was applied to each of the ten sheathed heaters of the present invention, and they exhibited excellent electrical insulation.

In this way, 5UE430LX is used as an electrical outlet terminal.
'! Furthermore, by using a material with a linear expansion coefficient of 1oO to 130×10 −7 /° C. as the low melting point glass, it was possible to obtain a sheathed heater having a sealing structure with excellent mechanical strength.

Similarly, in the embodiment of the present invention, as the metal pipe, NC
Faoo (linear expansion coefficient: 170~18゜x 1o -'
5US3 having a coefficient of linear expansion close to N CF 800.
04.5US321 may also be used.

1. - Although 5US430LX was used as the air extraction terminal, it may also be a product equivalent to 5US430LX which has a linear expansion coefficient almost close to 5US43QLX (linear expansion coefficient: 11'O to 120X10°C).

Effects of the Invention As is clear from the above explanation, according to the 7-Z heater of the present invention, 5US430LX can be used as an electrical outlet terminal.
A glass sealing material with a linear expansion coefficient of 100 to 1 is used as a glass sealing material to seal the nitrogen gap between the metal pipe and the electrical extraction terminal.
By using a low melting point glass of 30×10′/′C, a sheathed heater having a sealed structure with excellent mechanical strength can be obtained, and its practical value is great.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a sheathed heater according to an embodiment of the present invention, and FIG. 2 is a front view of a main part showing a state in which a load is applied in the same embodiment. 1... Electrical outlet terminal, 3... Metal pipe, 6... Low melting point glass. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] 5US430LX is used as the electrical outlet terminal, and a glass sealing material with a linear expansion coefficient of 100 to 130X is used to seal the gap between the metal pipe and the electrical outlet terminal.
A sheathed heater made of low melting point glass of 10'/''C.