JPS6041667Y2 - sheet heater - Google Patents

Description

[Detailed explanation of the idea] Himi's invention relates to the improvement of planar heaters.

Planar heaters are generally protected from meandering heating wires that are sandwiched between a heat insulating material and a heat sink (see FIG. 4B).

However, such a planar heater has an air layer between the insulation material and the heat sink, and this air layer is heated and causes convection, so heated air escapes from the top and cold air enters from the bottom. heating effect decreases.

In addition, the minimum pitch of this meandering heating wire is twice the minimum bending radius r, so the amount of heat generated per unit area is small, and furthermore, both sides of the meandering direction of the heating wire are open alternately. Therefore, the amount of heat generated is small and both edges tend to be cold, resulting in temperature unevenness.

An object of the present invention is to provide a planar heater that reduces heat loss due to convection, generates a large amount of heat per unit area, and has little temperature unevenness.

The embodiments of the present invention will be described in detail with reference to the drawings.
2 and 2 show a planar heater 10 according to the present invention,
This planar heater 10 is sandwiched between a heat insulating material 12 and a heat radiating plate 14 and extends from a meandering heating wire 16.

A reflective plate 18□ is arranged between the heat insulating material 12 and the heat generating plate 16, but this reflective plate may be omitted.

The heat insulator 12 can be made of glass wool, plastic foam, etc., the heat sink 14 can be made of iron, and the reflector 18 can be made of aluminum.

Although it is preferable that the heating wire 16 is an inorganic insulated heating wire called a so-called sheathed heater, the present invention can be applied to other planar heaters made of heating wires.

In the planar heater 10 of the present invention, as particularly shown in FIG. 2, the meandering line 16a and return line 16b of the heating line 16 are arranged non-parallelly so that they are almost closed at the opening 16d on the opposite side to the turning point 16c. It is extending.

In this way, as shown in FIG. 4A, the heating wire 16
The minimum pitch can be about half that of the conventional method (see FIG. 4B), and the density can therefore be about twice that of the conventional method.

In addition, since the wire 16a and the return wire 16b of the heating wire 16 are almost closed in a loop shape, there is no escape due to the convection of the air layer therein, and thermal efficiency is improved. Since the adjacent turning points 16c of the heating wires are close to each other, the temperature does not decrease at both ends.

FIG. 3 shows another embodiment of the present invention in which the heat insulating material 12, the heat dissipating plate 14, and the reflecting plate 18 have curved surfaces, and in this embodiment, the heating wire 16 has the same pattern as in FIGS. 1 and 2. It will be placed in

According to the present invention, as mentioned above, the maximum density of the heating wire can be increased, so the amount of heat generated per unit area can be increased, and convection is suppressed, resulting in less heat loss and improved thermal efficiency. Furthermore, there is no unevenness in the distribution of heating lines, and heat can be emitted uniformly from the entire surface.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a planar heater according to the present invention, FIG. 2 is a rear view of the heater of FIG. 1 with the heat insulating material and reflective plate omitted, and FIG. FIGS. 4A and 4B are schematic diagrams showing the heat generation line distribution of the present invention and the conventional one. 10... Planar heater, 12... Heat insulating material, 14... Heat sink, 16... Heat generating wire,
16a...on line, 16b...on return line, 1
6c... Turning point, 16d... Opening.

Claims (1)

[Scope of utility model registration request] In a planar heater consisting of a meandering heating wire sandwiched between a heat insulating material and a heat sink, the meandering lay wire and return wire of the heating wire extend so that the opening on the opposite side to the turning point is almost closed. A planar heater characterized by: