JPS5852314B2 - heating element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating element used in electric heating appliances such as electric water heaters.

Generally, heating elements used in electric water heaters and the like are equipped with various overheat prevention devices.

For example, a short-circuiting molten metal may be placed opposite a heat-generating wire wound around an insulating substrate at a certain interval, so that the point where the heat-generating wire becomes abnormally overheated melts and short-circuits the heat-generating wire, or if the heat-generating wire becomes dry-fired, the heat-generating wire The structure is such that it overheats abnormally and melts and breaks.

However, the former type has a large number of parts, and the orientation of each part is a problem in the manufacturing process, resulting in an overall high cost.

In addition, the latter had a large variation in the time required for the wire to break, and had a built-in risk of fire.

The present invention improves and eliminates such conventional drawbacks, and aims at simplifying the configuration and reducing costs.

One example of this will be explained below using an electric water heater. 1 is a pot container, 2 is a hook supporting the same, and 3 is a heating element provided in the pot container 1. This will be explained in detail using FIGS.

4 is an insulating substrate made of mica or the like, with several through holes 5 in appropriate places.
is formed.

A heating wire 6 is wound around the outer surface of the insulating substrate 4, and is wound so that the heating wires 6a6b on the front and back sides intersect at the through hole 5 portion.

Reference numerals 7 and 8 designate cases in which the insulating substrate 4 is clamped and fixed from both sides of the heating wire 6 via a holding plate 9, and has a liquid-tight structure.

A hole 8a is provided in the center of the case 8, and a screw tube 10 is attached to the hole 8a to connect the lead wire 11 of the heating wire 6.
is the extraction.

In the above configuration, when the heating element 3 is baked, the heating wire 6 located in the through hole 5 part generates abnormal heat than other parts due to the space of the through hole 5, and the temperature becomes higher. The heating wires 6a and 6b expand and suspend and float,
Both heating wires 6a and 6b come into contact at the intersection, causing an electrical short circuit.

After this short circuit, the temperature rises abnormally due to the self-heating of some of the heating wires 6, and the heating wires 6 are fused by this heat to prevent excessive temperature rise.

In addition, in this configuration, in the case of power consumption of 100V-500W, after a short circuit, some of the heating wires 6 are overloaded by about IKW, causing abnormal heat generation, and the heating wires 6 close in about 1 to 2 minutes.
We have obtained experimental results that show the melting of .

As described above, according to the present invention, a through hole is provided to actively generate abnormal heat in a part of the heating wire, and this abnormal heating promotes disconnection of the heating wire and prevents excessive heating. The configuration is extremely simple and the cost can be significantly reduced without the need for any There is little variation in wire breakage, and there is almost no risk of fire, etc., and its value is unparalleled.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway view of an electric water heater using a heating element according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of the heating element, Fig. 3 is a plan view of the main part, and Fig. 4 The figure is an enlarged explanatory view of the main parts. 4...Insulating substrate, 5...Through hole, 6...Heating wire.

Claims (1)

[Claims] 1 In a heating element formed by winding a heating wire around an insulating substrate,
A heating element formed by providing a through hole in the insulating substrate, and making heating wires on the front and back of the insulating substrate intersect at the through hole portion.