JPS59167988A - Insulating structure of flat 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 (a) Field of Industrial Application The present invention relates to a flat sheath heater comprising an insulated heating element disposed inside a flat sheath, and particularly to an insulating structure of the heating element.

(B) Prior Art Conventional sheath heaters generally have oxidized magnesia interposed between the sheath and the heating element. The insulation structure of such a heating element is widely applied when the sheath has a round shape, but in the case of a flat sheath, it is extremely difficult to position the heating element in the center of the sheath. It was often the case that the insulation performance would be impaired due to unevenness.

(c) Purpose of the Invention The present invention improves the insulation performance between the sheath and the heating element by maintaining a regular distance between the flat sheath and the heating element inserted into the sheath.

(b) A comparatively hard first mica plate on which a heating element is wound in a spiral shape having the configuration interval of the invention, and a heating element having a width larger than the winding width of the heating element, and determining the winding width. relatively hard second and third mica plates that protrude from both ends of the heating element and sandwich the heating element; and a relatively soft fourth mica plate that covers the entire periphery of the second and third mica plates. An insulating structure for a flat sheath heater.

(E) Embodiment FIG. 1 shows a perspective cross-sectional view of a flat sheath heater product according to the invention. According to this, the heating element (3) wound around the first mica plate (2) located at the center of the flat sheath (1) has both ends (3A
) and (3B), the second mica plate (4) and the third mica plate protrude from
mica plates (5), and the second and third mica plates (5)
The entire circumference of the mica plates (4) and (5) is the fourth mica plate (6)
covered by. The fourth mica plate (6) has a U-shaped cross section bent at the center, and the second and third mica plate (4)
) and (5), two U war mica plates (7) and (8), and a tape-shaped mica plate (9) wound around these.

Thus, the first mica plate (2) prevents the heating element (3) from crossing and maintains the desired amount of heat generation, and the second, third and fourth mica plates (4), (5) and (6) improve the insulation performance between the sheath (1) and the heating element (3) by maintaining an appropriate insulation distance between the sheath (1) and the heating element (3).

Next, the manufacturing method for producing the flat sheath heater will be described in detail. First, as shown in FIGS. 2 and 3, plate-shaped heating elements (3) are spirally spaced at equal intervals along the periphery of the first mica plate (C), which has a rectangular cross section and is relatively hard. Roll it around. After wrapping, press the whole thing to form the first mica plate (2)
and fix the heating element (3) so that it does not move.

After this, as shown in FIGS. 4 and 5, a relatively hard second mica plate (4) and a third mica plate having a rectangular cross section and a width larger than the winding width of the heating element (3) are formed. (5) clamps the heating element (3). At this time, the second and third mica plates (
4) and (5) are designed to hold the heating element (3) in such a manner that they protrude from both ends (3A) and (3B) of the heating element (3), which determine the winding width of the heating element (3).

Next, as shown in FIGS. 6 and 7, one end of the heating element (3) exposed ( 3A), which covers the second and third mica plates (4) and (5), and further includes a relatively soft second U which is bent at the center to form a U shape.
The mold mother plate (8) substantially covers the first U war mica plate (7), including the exposed other end (3B) of the heating element (3). As a result, the second and third mica plates (4) and (5)
) is completely covered, and thus the heating element (3) is also completely covered.

Next, as shown in Fig. 8, a relatively soft tape-shaped mica plate (9) is wound spirally around the second U-shaped mica plate (8), with some parts overlapping, and the ends are glued. Secure with tape (not shown). As a result, the entire circumferences of the first and second U war mica plates (7) and (8) are completely covered, and
Both ends (4A) and (4B) of the second mica plate (4), both ends (5A) and (5B) of the third mica plate (5), and the first
Both ends (7A) and (7B) of the second U mica plate (7) and both ends (8A) and (8B) of the second U mica plate (8) are both ends (3A) of the heating element (3). The exposed portion of (3B) is bent inward so as to be narrowed.

On the other hand, the cylindrical sheath (10) shown in Fig. 9 is processed into a state in which the one shown in Fig. 8 can be inserted with plenty of room, and the sheath shown in Fig. 10 (the one shown in Fig. 8 that has gone through the above steps is inserted into IIJ). After that, this is finally pressed to form a flat sheath (1) that tightly adheres to the tape-shaped mica plate (9) located at the outermost side of the insulating material, thereby completing the flat sheath heater shown in Fig. 1. It is something.

In addition, in the embodiment of the present invention, the fourth mica plate (6) is constituted by the first and second U war mica plates (7) and (8) and the tape-shaped mica plate (9), and the second and W, 3 mica plate (4)
and (5) are coated in multiple layers, but U war mica plate (7
) and (8) or tape-shaped mica plate (9),
Even if the second and third mica plates (4) and (5) are entirely covered, insulation between the heating element (3) and the flat sheath (1) can be sufficiently achieved.

(F) Effects of the Invention Since the present invention can maintain a tight distance between the heating element and the flat sheath, the insulation performance between the heating element and the sheath is greatly improved, especially at both ends of the heating element which has weak insulation. This improves the insulation between the rounded portion and the sheath.

Further, the flat sheath heater is more advantageous than the round sheath heater in bending, and even in this bending, the flat sheath heater of the present invention does not expose the heating element and impair insulation.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the flat sheath heater of the present invention, FIG. 2 is a front view showing a state in which a heating element is wound around a first mica plate, and FIG. Figure 4 is a front view showing the thing in Figure 1 held between the second and third mica plates, Figure 5 is a sectional view taken along line B-B in Figure 4, and Figure 6 is the thing in Figure 4. A front view showing the state covered by two U-shaped base plates, FIG. 7 is a sectional view taken along the line C-C in FIG. 6, and FIG. FIG. 9 is a sectional view of the cylindrical sheath, and FIG.
It is a sectional view of a sheath made by processing the one in the figure. (1)... Flat sheath, (2)... First mica plate, (3)... Heating element, (3A), (3B)...
Both ends of the heating element, (4)...second mica plate, (5)
...Third mica plate, (5)...Fourth mica plate, (
7)...First U-shaped base plate, (8)...Second U
Mold placement mother plate, (9)...tape-shaped mica plate O Fig. 1 Fig. 4

Claims (1)

[Claims] 16 In a flat sheath heater in which an insulated heating element is disposed inside a flat sheath, a relatively hard first mica plate on which the heating element is wound in a spiral shape with a gap therebetween; Relatively hard second and third mica plates, which have a width smaller than the winding width and hold the heating element in a state protruding from both ends of the heating element whose winding width is determined; An insulating structure for a flat sheath heater, characterized in that a fourth mica plate, which is relatively soft, is provided to cover the entire circumference of the mica plate No. 3.