JPS6321115Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heater that is attached to an electric water heater or the like.

Electric water heaters have a built-in heater at the bottom of the container. If the inside of the container is empty when the heater of such a water boiler generates heat, the temperature of the heater itself and the container will rise abnormally, which may cause a fire.

The purpose of this invention is to solve the above-mentioned problems, for example, to eliminate the heat generating function during dry firing.

This idea is to make a part of the heating wires of the heating element intersect so that the abnormal temperature rise during heating causes the heating wires to melt at the intersection.

Hereinafter, embodiments of this invention will be described based on the accompanying drawings.

As shown in FIGS. 1 to 3, the heater according to this invention is composed of a metal sealed case 1 and a circular heating element 10 housed in the case 1. Insulating plates 20 are stacked on both sides of the body 10, and a stainless steel plate 30 is further stacked on the outside thereof.

The heating element 10 includes a pair of semicircular mica plates 1
1 and 11, and a large number of notches 12 are formed on the outer periphery of each mica plate 11.

A pair of mica plates 11, 11 are arranged in a disk shape, and the heating wire 13 wound around the outside of one mica plate 11 is wound around the outer periphery of the other mica plate 11 to be held in a disk shape. A nichrome wire can be used as the heating wire 13, and the heating wire 13 is wound around the outside of each mica plate 11 so as to pass through the notch 12 on the outer periphery of the mica plate 11.

A pair of band-shaped mica plates 14, 14' are superimposed on one surface of the heating element 10, and the band-shaped mica plates 14, 14' intersect with each other. Further, the length direction of each of the strip-shaped mica plates 14, 14' intersects the heating element 13 wound around each mica plate 11.

The belt-shaped mica plates 14, 14' have insertion holes 15 at both ends thereof, and the winding start end 1 of the heating wire 13 is inserted into the insertion holes 15.
3' is inserted through the lower portion of the lower belt-shaped mica plate 14 into the insertion hole 1
5 and is pulled out along the longitudinal direction of the surface of the lower belt-shaped mica plate 14, and its ends are successively inserted through the other insertion hole 15 into each of a plurality of holes 16 formed in the center of the mica plate 11 and pulled out below the mica plate 11.

The winding end 13'' of the heating wire 13 is inserted into the insertion hole 15 at the end of the upper band-shaped mica plate 14' and pulled out along the longitudinal direction of the surface of the upper band-shaped mica plate 14'. They are inserted into a plurality of holes 16 formed in the center of the mica plate 11 through the insertion holes 15 and pulled out below the mica plate 11.

Hole 1 formed in the center of each mica plate 11, 11
A pair of reinforcing heating wires 17 are inserted into the insertion holes 15 at the ends of the mica plates 14 and 14', and each reinforcing heating wire 17 is placed along the end of the heating wire 13. Three strands are twisted together. This twisted wire becomes the lead wire 18,
Each lead wire 18 is connected to an insulating plate 20 below the heating element 10.
and is inserted into the hole 31 in the center of the stainless steel plate 30, further inserted into the inside of the screw cylinder 2 fixed to the center part of the bottom plate of the case 1, and pulled out to the outside, and the cylindrical insulator 19 is fitted on the outside thereof. There is.

The heater shown in the embodiment has the above-described structure, and this heater can be used in, for example, a water heater.

Now, for example, when the heater of this invention is used in a water heater, when the lead wire 18 is energized, the heating element 10 generates heat, which can heat the water placed in the container. . By the way, when the inside of the container is empty, the heater itself becomes high temperature, and a part of the heating wire 13 extending along the lower band-shaped mica plate 14 is heated from above and below, so this part is heated by other parts. The heating wire 13 is more likely to melt down than the other parts, and will melt if left unheated for a long time, and when the heating wire 13 is broken, it becomes impossible to conduct electricity and loses its function as a heater.

Incidentally, when the heater according to this invention was attached to a water heater and a dry firing test was carried out, as shown in FIG. It was fused together with the lower band-shaped mica plate.

As described above, according to this invention, since the winding start end and winding end of the heating wire are crossed with the heating wire wrapped around the mica plate, abnormal heating of the heating element may cause the heating wire to Can be fused.
For this reason, the function of the heating element can be lost during dry heating, etc., and the occurrence of a fire can be prevented.

In addition, since the heating wires wound around the mica plate are crossed at the beginning and end of the winding, in the event of abnormal heating, the central heating wire will be heated from above and below among the three heating wires that cross each other. will be done.

Therefore, in the event of abnormal heating, the heating wire can be melted down in a very short time and reliably, making it extremely safe.

In addition, since the pair of mica plates are symmetrical, manufacturing is easy and a heater can be obtained at low cost.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional plan view of the heater according to the invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a perspective view of the heating element as above, and Fig. 4 is as above. FIG. 3 is a cross-sectional plan view showing a disconnected state of the heating wire. 1... Case, 10... Heating element, 11... Mica plate, 13... Heating wire, 14, 14'... Band-shaped mica plate.

Claims (1)

[Scope of utility model registration request] In a heater in which a heat generating wire is wound around the outside of a circular mica plate divided into two parts, the mica plate is formed of a symmetrical semicircular mica plate, and the winding start of the heat generating wire wound around the semicircular mica plate is The winding end of the heating wire wound on the other semicircular mica plate is crossed with the heating wire wound on the mica board, and the winding start end and winding end are crossed with each other, and the above-mentioned A heater characterized in that a band-shaped mica plate is provided below the winding start end and the winding end end.