JP2745736B2 - Electric heating element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric heating element mounted on an electric water heater for heating and keeping a stored liquid.

2. Description of the Related Art Conventionally, in a heating element of this type, as shown in FIG. 4, a container having a bottomed cylindrical heat-transfer plate 26 projecting from the bottom surface.
Insulation materials 30 and 31 covering the upper and lower surfaces of a heating plate 29 with a main heating wire 27 and an auxiliary heating wire 28 wound integrally and a heat diffusion plate 32 of good thermal conductivity are attached to the back of the bottom surface of the bottom 25 by a backing material 33. It had been.

Problems to be Solved by the Invention In such a conventional configuration, when an attempt is made to increase the wattage of the heating element, the watt density naturally increases. That is, as the temperature of the heating wire increases, the burden on the heating wire increases,
In addition, since the thermal expansion also increases accordingly, there is a durable problem that the main heating wire and the auxiliary heating wire are short-circuited and disconnected.

An object of the present invention is to solve the above-mentioned problems and to provide a heating element with improved durability, reliability, and assemblability.

Means for Solving the Problems In order to achieve this object, the present invention provides a container having a heat transfer plate protruding from the bottom and having a bottomed cylindrical shape. A first heating plate covered with
Power consumption is smaller than that of the first heating plate, and both upper and lower
And a second heat generating plate covered with a fourth insulating material, a heat diffusion plate having good thermal conductivity, and a first back plate, and the second heat generating plate is insulated from the third and fourth insulating plates. In the central part of the material, there are provided holes larger than the first heat generating plate, the first and second insulating materials, and the holes provided in the central part of the heat diffusion plate, and the first back plate has the respective holes. Is provided with a two-stage pressing surface.

Operation The present invention has the above-described configuration, and allows the second heating plate and the third
And a first heating plate and a hole larger than a hole provided in a center portion of the first and second insulating materials and the heat diffusion plate are provided in a central portion of the fourth insulating material; 2 corresponding to the hole
Since the pressing surface of the step is provided, the durability is ensured, and the heat conduction to the sensor detecting surface provided at the center of the bottom surface by the first heating element and the radiant heat is improved, and the empty-cooking detecting performance can be improved. Further, since the diameters of the holes provided in the central portion of the heat generating plate and the insulating material are different, it is possible to prevent a mistake in the order of assembling the parts, and to improve the assembling, safety and reliability.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

In the drawing, reference numeral 1 denotes a heat transfer plate having a central portion protruding upward in a substantially D-shape to form a peripheral side portion 1a, and by fixing the outer peripheral portion to the lower end of the cylindrical body in a liquid-tight manner by welding or the like. A metal liquid storage container 23 is formed. Reference numeral 24 denotes an exterior body that wraps the container 23 via a space. A heating element 3 is mounted on the lower surface of the heat transfer plate 1 via a heat conductive plate 2 made of, for example, aluminum or a surface-treated steel plate having a good thermal conductivity.
The heating element portion 3 includes a first heating element 5 and a second heating element 6 disposed above and below a heat transfer plate 4 having good thermal conductivity such as aluminum or a surface-treated steel plate. The heating element 5 has a first heating plate 7 around which a first main heating wire 8 is wound, a first insulating material 9 and a second insulating material 10 above and below, and the second heating element 6 Second
An auxiliary heating wire 12 having a smaller amount of electric power than the first main heating wire 8 is wound around a heating plate 11 and a third insulating material 13 and a fourth insulating material are vertically arranged.
Has 14

The first insulating material 9, the first heating plate 7, and the second insulating material
10 and the heat diffusion plate 4 have holes a15, b16, c17, d18 in the center,
The third insulating material 13, the second heating plate 11, and the fourth insulating material 14.
Are holes e19, f larger than the holes a15, b16, c17, d18 at the center.
These have a central portion protruding upward, an outer peripheral side portion 22c, a central through hole, and a hole a1.
5, b16, c17, d18 and holes e19, f20, g21. The heat transfer plate 1 is formed by the first back material 22 having good thermal conductivity such as a surface-treated steel plate having two-stage pressing surfaces 22a and 22b. It is mounted with the presser margin on the lower surface.

With the above-described configuration, the first back plate 22 passes from the first heating plate 7 through the second insulating material 10 and the heat diffusion plate 4.
To conduct heat from the first back plate 22 to the sensor detection surface 1b provided at the center of the bottom surface, so that at the time of boiling and empty cooking, heat conduction to the sensor detection portion 1b is improved, Detection can be performed accurately, and reliability and safety can be further improved.

Effect of the Invention As described above, in the heating element of the present invention, the first heating plate and the first and second insulating materials are provided at the center of the second heating plate and the third and fourth insulating materials. A hole larger than the hole provided in the center portion of the heat diffusion plate is provided, and the first back plate is provided with two-stage pressing surfaces corresponding to the holes, so that durability is secured and the first heat generation is performed. The heat conduction to the sensor detecting unit by the body and the radiant heat is improved, and the empty cooking detection performance and the like can be improved. Further, since the diameters of the holes provided in the central portion of the heat generating plate and the insulating material are different, misassembly of parts can be prevented, and assemblability, safety and reliability can be improved.

[Brief description of the drawings]

1 to 3 show one embodiment of the present invention.
Figures are exploded perspective views of the electric heating element, FIGS. 2 and 3 are cross-sectional views of main parts and an enlarged cross-sectional view of the main part of the electric water heater equipped with the heating element, and FIG. 4 is an exploded perspective view of a conventional electric heating element. FIG. 1... Heat transfer plate, 4... Heat diffusion plate, 7.
9 first insulating material, 10 second insulating material, 11 second
Heating board, 13 ... third insulating material, 14 ... fourth insulating material,
15: Hole a, 16: Hole b, 17: Hole c, 18: Hole d, 19
... holes e, 20 ... holes f, 21 ... holes g, 22 ... first back plate, 22a ... holding surface a, 22b ... holding surface b, 23 ... container.

Continuation of the front page (56) References JP-A-57-74991 (JP, A) JP-A-57-74990 (JP, A) JP-A-57-6627 (JP, A) JP-A-3-149793 (JP) , A)

Claims (1)

(57) [Claims] 1. A first heat generating plate having upper and lower surfaces covered with first and second insulating materials on a back side of a bottom surface of a container having a heat transfer plate protruding from the bottom surface and having a bottomed cylindrical shape. A second heat generating plate having lower power consumption than the first heat generating plate and both upper and lower surfaces covered with third and fourth insulating materials, a heat diffusion plate having good heat conductivity, and a first back plate; In the central portion of the second heat generating plate and the third and fourth insulating materials, a hole larger than the hole provided in the central portion of the first heat generating plate and the first and second insulating materials and the heat diffusion plate is provided. Provided,
The first back plate has two holes corresponding to the respective holes.
An electric heating element characterized by having a step holding surface.