JPH0637982B2 - Heating element for microwave oven - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is an electronic device that generates heat by irradiation of microwaves emitted from a magnetron of a microwave oven and emits infrared rays (heat rays) to burn an object to be cooked. The present invention relates to a heating element for a microwave oven.

<Prior Art> Generally, a microwave oven is a cooking device that guides microwaves radiated from a magnetron into an oven to irradiate an object to be cooked and heats the object to be cooked for cooking. Therefore, since the food to be cooked is not browned, there is a drawback in that, for example, in a fish dish or the like, the lack of browning does not cause appetite. Therefore, there is a microwave oven in which a sheathed heater is built-in so that the heat generated by the heater is directly applied to the food to be cooked in parallel with the heating of the food to be cooked by the microwave.

However, since the two types of heating means as described above are used,
A magnetron and a heater are required as a heat source, which is a factor of cost increase and the structure is complicated and the entire apparatus is enlarged. Recently, for the purpose of improving these problems, a plate having a double structure formed by polymerizing a heat-generating material that generates heat by irradiation with microwaves and a heat insulating substrate is used as a heat-generating body, and only microwaves are used for dielectric heating and heat radiation. The same applicant has made a proposal to have both heating effects. (Jpn. Pat. Appln. No. 61-149372) In addition, a similar proposal (Japanese Patent Publication No. 62-122091) has been made for the purpose of heating an object to be heated which has a low microwave absorptivity.

<Problems to be Solved by the Invention> However, these proposals do not specify a specific material, and do not specify an inorganic binder, which is an important factor in practical use, so that the heat generation efficiency is high and the heat generation is practical. It was difficult to get a body.

<Means for Solving Problems> Microwave absorbents mainly composed of silicon carbide particles or powders are bonded to each other with an alkali metal silicate-based inorganic binder, and the microwave absorbents are bonded with an alkali metal. The heating element is made of a silicate-based inorganic binder and is adhered to a base material having microwave transmission properties and heat insulation properties.

<Operation> Since silicon carbide particles (or powder) adhered to a base material having a microwave transmitting property and a heat insulating property have conductivity, they absorb the microwave irradiation and absorb the microwave irradiation. An electric current flows in the granules (or powder) and is heated by the Joule heat. At this time, since the alkali metal silicate-based inorganic binder that joins the particles together contains the alkali metal ions and has conductivity to some extent, it also absorbs microwaves and the electric current between particles becomes similar. It also serves as a heating element and has a high heating efficiency.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of a microwave oven. The microwave emitted from the magnetron 1 serving as a heat source for heating the microwave is guided to the waveguide 2 and is radiated from the irradiation port 3 to the oven 4. The microwave radiated into the oven 4 is absorbed by the container-shaped heating element 5 and converted into heat, thereby raising the temperature inside the heating element. The high temperature heating element 5 emits infrared rays (heat rays). Cooked object 7 placed on the wire net 6 inside the heating element 5
(For example, potatoes, fish, steaks, etc.) are first microwave-heated by a part of the microwaves that have passed through the heating element, and then heated by infrared rays emitted from the heating element 5 that heats to a high temperature, so that the surface is burnt. A delicious dish with a mark is completed.

FIG. 2 is an enlarged sectional view of the heating element 5. Particles (or powder) 5a of silicon carbide are added to a base material 5c (for example, ceramic fiber board, porous ceramics, etc.) having microwave permeability and heat insulation properties, and an alkali metal silicate-based inorganic binder 5b (for example, Sakai Chemical Industry). Betaq Co., Ltd. # 1
200). Inorganic binder 5b
Also serves to physically and electrically bond the silicon carbide particles 5a to each other. The compounding ratio of the inorganic binder is 1/2 by weight of the silicon carbide particles (powder) (Betax # 12).
00) is suitable, and after a little addition of water and sufficient mixing, the substrate is coated and adhered by brushing or spraying.

Fig. 3 shows various inorganic binders with a weight ratio of 1/2 to 6 g of silicon carbide powder (sample mixed with powder of various particle sizes) on 80 m x 80 m x 5 mm ceramic fiber board. It is a table showing the average surface temperature of the heating element when using.

However, the measurement condition is that the above test piece has an internal volume of 100 x 1
The surface temperature of the test piece was measured when the test piece was placed in a container made of ceramic fiber board having a thickness of 00 × 40 mm and a thickness of 20 mm and irradiated with a microwave of 500 W for 5 minutes.

<Effect> The heating element for a microwave oven of the present invention is a dry-curing type in which the alkali metal silicate-based inorganic binder for bonding the microwave absorber and adhering to the base material is cross-linked and cured by drying. Since it is a binder, it can be hardened simply by adhering the microwave absorbent with the alkali metal silicate inorganic binder and then drying it, and without any special treatment such as firing, the microwave absorbent can be easily used. Can be glued.

Moreover, since the alkali metal silicate-based inorganic binder contains alkali metal ions, the alkali metal silicate-based inorganic binder itself has conductivity and absorbs microwaves as well as the microwave absorber. Since it works by passing an electric current between the particles or powder of the microwave absorber,
The heating efficiency of the microwave absorbent is improved, and a microwave heating element having a very high heating efficiency can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a microwave oven provided with a heating element according to the present invention, FIG. 2 is an enlarged cross-sectional view of the heating element according to the present invention, and FIG. 3 shows a heating element according to the present invention and another inorganic binder. It is a figure which shows the heat generation efficiency (displayed by surface temperature) of the used heat generating body. Reference numeral 5. Heating element 5a. Silicon carbide particles (powder) 5b. Alkali metal silicate inorganic binder 5c. Base material

Claims (1)

[Claims] 1. A heating element which generates heat by microwave irradiation of a microwave oven, wherein microwave absorbents mainly composed of silicon carbide particles or powders are bonded to each other with an alkali metal silicate inorganic binder. At the same time, a microwave heating element is characterized in that the microwave absorbing material is adhered to a base material having a microwave transmitting property and a heat insulating property with an alkali metal silicate inorganic binder.