JPS6266590A - Panel 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 Field of Industrial Application The present invention relates to a surface heater used as a heat source for appliances that utilize electrical energy, such as space heaters, cooking appliances, and drying appliances.

BACKGROUND OF THE INVENTION In recent years, surface heaters have come into the spotlight as heating elements that meet the demands for thinner equipment and uniform heating, and various surface heaters have been developed as shown below.

(1) A structure in which a heater is wound around an insulating substrate such as mica.

@) It has a structure in which a conductive pattern is formed on an alumina substrate using a conductive paste such as tungsten, and then an alumina substrate is placed on top of it and then integrally molded.

(3) A device with a laminated structure in which a conductive pattern is formed between organic films such as silicon or polyimide.

However, the surface heater (0) has poor heat transfer to the heated object, has problems with moisture resistance because the heater is not sealed, and The reality is that they each have their own problems, such as a weak heat capacity and a large heat capacity, resulting in a long start-up time.Furthermore, the surface heater (3) has a low heat resistance and has problems with its lifespan.

Among the surface heaters having various problems as described above, the so-called mica heater, which has a structure in which the heater is wound around an insulating substrate such as a mica board (1) 11, which is inexpensive, is often used.

This mica heater, as shown in Japanese Patent Application Laid-open No. 57-34687, is a ribbon-shaped heating element wrapped around a mica plate and integrated into a sandwich shape with two sheets of insulating mica. It is applied to various products such as jar pots and heat insulators.

Other conventional heating elements include heating wires wound into coils and installed in a spiral shape in grooves of a ceramic plate, which are used as so-called electric stoves.

tin oxide (5nO2) and indium oxide (In2o3)
Glass heaters with heat-generating surfaces made of metal oxide films deposited with metal oxides have also been proposed.

Problems that the invention attempts to resolve However, since it is necessary to use at least three mica plates in such a surface heater using mica plates, the heat capacity inevitably increases, and as a result, the heat capacity of the heated There was a problem that heat transfer to objects was delayed. In addition, because there are parts where the mica plate and the heating element are in contact and parts where they are not, there are problems in terms of lifespan, such as wire breakage due to local heating. Furthermore, the heat resistance temperature of mica board is 45
Since the temperature is about 0° C., there is also the problem that the watt density cannot be increased.

A bigger problem is that since it is a surface heater, it is very difficult to prevent heat radiation from the back surface, and therefore the thermal efficiency for the object to be heated decreases.

Also, if you want to use the mica plate as an outer cover, the thickness of the plate should be 0.
It is necessary to have a thickness of 8H or more (according to the Electrical Appliance and Materials Control Law).If the plate thickness becomes thicker, there are problems such as a longer stand-up time.

On the other hand, glass heaters, which have been proposed as new heaters, use an infrared reflective film such as tin oxide (5nO2) as the heat generating surface, so like mica heaters, the heat emitted from the back surface cannot be transmitted even if it is reflected. A decrease in thermal efficiency is inevitable. Furthermore, since the glass substrate has a large heat capacity, the rise time is slow and there are also problems in heat resistance.

The present invention solves these problems, and aims to provide a surface heater that can be started up quickly and has a high wattage density.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a hot part by sandwiching the ends of a heater element made of a smooth mesh metal foil with an insulating material such as mica and fixing them by pressure. It consists of a heater unit floating in the air sandwiched between heat-resistant glass and a reflective plate.

Function According to the above configuration, the ends of the heater element made of a smooth mesh metal foil are sandwiched between mica or other insulators and fixed by pressure, so that the red-hot part floats in the air. The heat capacity as a heater is small, and as a result,
In addition to speeding up the start-up time, it also prevents local heating by eliminating contact between the insulator and red-hot parts.
Longer life is possible. In addition, since heat-resistant glass is used as the outer covering, it is resistant to external mechanical shocks.In addition, heat-resistant glass transmits over 90% of electromagnetic waves up to 5 μm, so the heating element can be heated to 800 degrees Celsius. As heated, from Blank's law approximately 60 of the radiant energy
The remaining 40% is absorbed by the heat-resistant glass and is irradiated onto the object to be heated as secondary radiation from the heat-resistant glass.

Furthermore, by providing a reflective plate on the opposite side of the heat-resistant glass with the heater unit in between, the energy radiated from the back side of the heating element is reflected by the reflective plate and passes through the gap between the heating elements and passes through the heat-resistant glass. It passes through and is irradiated onto the object to be heated.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In FIGS. 1 to 4, 1a and 1b are insulating mica, and the portions of the insulating mica 1a and 1b where the heat generating portion of the heater element 2 is located are cut out. The heater element 2 has a smooth mesh structure, and an electrical outlet terminal plate 3 is connected to the end thereof by spot welding.

As a means for obtaining the smooth mesh heater element 2, a metal foil body (for example, Fe-Cr-Al1 alloy, SU
S304, 5US430, Ni-Cr alloy, etc.) is processed into a lath mesh shape, and then rolled to flatten the convex portions and cut into a desired pattern. FIG. 4 shows an embodiment thereof. In addition, the mesh-shaped heater element may be manufactured by etching, by using a metal ivy, or by using punched metal.

Heater element 2 manufactured by the method described above is
The heater element 2 was sandwiched between sheets of insulating mica 1a and 1b, and the ends of the heater element 2 were crimped and fixed with an inorganic adhesive 4 to obtain a heater unit A as shown in FIG. 2b.

FIG. 2a shows a heat-resistant glass 4, which is a plate-shaped Pyroceram (trade name), Milacron (
(product name) was used. FIG. 2C shows a reflection plate 6, and the material used for this reflection plate 5 is an aluminized steel plate with a bright finish.

The assembly of heater unit A, heat-resistant glass 4, and reflector plate 5 is as follows:
Place the power count plate 3 of the heater unit A on the stepped part 5a of the reflector 5 so that it is located in the notch 6b of the reflector 5, place the heat-resistant glass 4 on top of it, and then remove the reflector. The heater unit A, the heat-resistant glass 42, and the reflector plate 6 were integrated by bending the 7 flange portions 6C of 6. As a result, the red-hot part of the υ heater element 2 becomes suspended in the air. FIG. 3 shows a sectional view of this embodiment.

A surface heater having the above structure was set at 400 W and compared with a conventional mica heater. In an experiment for baking bread, the cooking time was halved compared to the mica heater.

Effects of the Invention As is clear from the above explanation, according to the present invention, the heater unit is made of heat-resistant glass, in which the red-hot part of the heater element is suspended in the air, and the ends of the heater element are clamped and fixed with an insulating material such as mica. Since the reflector is sandwiched between the reflector and the reflector, it has various excellent effects as described below.

(1) Start-up time can be shortened.

(2) Since heat-resistant glass is used as the outer cover, it is resistant to mechanical shock from the outside, and radiant energy can be reflected by the reflector, so thermal efficiency can be greatly increased.

(3) The heat dissipation effect is high, and the red-hot part is not in contact with the insulator, so the watt density can be increased.

(4) Smaller size and lighter weight can be achieved.

(5) Since the heater element can be heated in a planar manner, it has a visual effect.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a surface heater showing an embodiment of the present invention, and Fig. 2 is an exploded view of the same surface heater, in which a is a perspective view of heat-resistant glass, b is a perspective view of a heater unit, C is a perspective view of the reflector, and Figure 3 is a cross-sectional view taken along the line A-A' of Figure M1.
FIG. 4 is a front view of the heater element on the same surface. 1a, 1b...Insulating material such as mica, 2...
...Converter element, A... Heater unit, 4... Heat resistant glass, 5... Reflector plate. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 4- Heat-resistant glass 5- Radiation grade 3 Figure 4

Claims (1)

[Claims] A heater unit consisting of a heater element made of a smooth mesh metal foil sandwiched between insulators such as mica and crimped and fixed so that the red-hot part floats in the air is sandwiched between heat-resistant glass and a reflective plate. A surface heater featuring: