JPS62128468A - Far-infrared radiation panel - 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 This invention relates to a thin planar far-infrared radiator that emits far-infrared rays when energized, and is used in cooking utensils, heaters, dryers, and the like.

Conventional technology The planar far-infrared radiators currently on the market are made by coating the surface of a metal plate with far-infrared radiating ceramics, and then placing a nichrome wire inside an electrical insulator on the back of the coating to heat it and further heat it. Some types are used, such as those with layers, or those made by arranging nichrome wire inside ceramics, molding it as one piece, coating the surface with far-infrared radiation paint, and firing it at a high temperature.

Problems to be Solved by the Invention Currently available planar far-infrared radiators have the following drawbacks.

l) The structure is complicated and the price is very high.

2) The radiator is thick and heavy. Therefore, the heat capacity is large, and the time (time required to reach the set temperature after energization) is extremely long.

8) Due to the large heat capacity, fine temperature control is not possible.

4) Since a nichrome wire is used as the heating element, the wire is easily broken, and if it is broken, it cannot be reused.

The present invention has been made to eliminate these drawbacks.

Means for Solving the Problems The present invention is constructed by bonding two thin hard mica plates with a conductive adhesive made of graphite.

Therefore, the radiator is extremely thin and light.

The structure is very simple and the price is low.

The heat capacity is very small, the rise time is short, the temperature distribution on the radiation surface is uniform, and fine temperature adjustment is possible. In particular, a device in which carbon fiber bundles are arranged at equal intervals between both terminals has excellent performance in terms of temperature distribution on the radiation surface, rise time, fine temperature control, etc. There is no chance of wire breakage because the conductive adhesive generates surface heat.

FIG. 1 shows an example of the planar far-infrared radiator of the present invention. A portion is shown cut away.

FIG. 2 shows an enlarged view of section A in FIG.

In the figure, (1) is a hard mica plate with a thickness of 0.2 to 0.3.

Far-infrared emitting ceramics (2) are baked on the surface of (1). (3) shows a conductive film formed from fine graphite powder. This adhesive is prepared by uniformly dispersing and suspending fine graphite powder having a particle size of 2 to 3 .mu.m in an aqueous sodium silicate solution as a fixing agent using an organic dispersant, and then heating and pressurizing the adhesive.

By adjusting the thickness of this conductive film, any electrical resistance can be achieved. (4) is 0.05 to 0. It is an electrical terminal made of In copper foil, and is temporarily fixed to mica using an adhesive. (4) has a copper washer (6
) and is fixed with a rivet (7) and connected to the lead wire (8). Thus, the current (9) flows uniformly through the conductive film (3).

Next, FIG. 3 shows a case in which carbon fiber bundles are arranged parallel to each other at regular intervals between both terminals of the planar far-infrared radiator shown in FIGS. 1 and 2.

FIG. 4 shows an enlarged view of section D in FIG. 3.

In the figure, the current entering from the terminal (10) flows in the direction of the arrow through the conductive film (11) as shown. In this case, if there is a slight difference in the thickness of the conductive film, there will be a slight difference in the amount of current flowing. However, carbon fiber bundle (12
), the current is uniformly redistributed along the B-C direction of (12). Is the volume resistivity of the conductive film (11) 0.050<7111? A; S cD Ni vs shite,
(12) This is because it has a low specific resistance of 0.0010 and disperses electricity well. Thus, the uniformly redistributed current is redistributed again by the following (13), and by repeating this process, a uniform current flows throughout the conductive film at the poles. Therefore, the temperature distribution of the heat generating surface becomes uniform, and far infrared rays corresponding to the temperature of the heat generating surface are emitted. Also, the time it takes to reach a certain temperature when energized (the time it takes to reach a certain temperature) becomes shorter.

Embodiment FIG. 5 is an example of the present invention, and shows a far-infrared ray emitter for a toaster. In the figure, the planar far-infrared radiator is composed of outer parts (14) and (16) and central part (15). You can bake two slices of bread at the same time by adding bread from E and F. Delicious bread can be baked in a short time using the far-infrared heating effect. (17) is a reflection plate. In this case, the current enters from G 14 → 15
→16 and is taken out from If. The electrical circuit is in series and is designed to generate more heat in the center. The resistance of the heating element can be freely designed by changing the thickness of the conductive film.

FIG. 6 shows the circuit voltages of the embodiments shown in FIG. 1 and FIG.

FIG. 7 shows the case where it is used in a dryer.

In the figure, (18) is a net conveyor, and three planar far-infrared ray emitters of the present invention are placed above and below the net conveyor.
They are arranged in series.

(19), (20), (21)... Upper radiator (22
), (23), (24)...F section radiator is shown.

The material is input from I, and is dried by far-infrared rays emitted from both the upper and lower surfaces on the net conveyor (18).
taken out from (25) and (26) are drive sprockets.

Effects of the Invention The invention will be described in detail by comparing a commercially available planar far-infrared radiator with that of the present invention.

■) Commercially available products have complex structures.

An example is shown in FIG. In the figure, (27) is a metal plate, and its surface is coated with far-infrared emitting ceramics (28).
) is burn-in. (29) is a nichrome wire embedded in the insulating material (30). (31) and (32) are heat insulating materials, and (33) is a lead wire. FIG. 9 shows what is seen from K in FIG. 8. In the figure, (3
4) is a framework.

Next, Fig. 10 shows a ceramic material with nichrome wire placed inside it and fired. A portion is shown cut away. In the figure, (34) is ceramic, (35) is nichrome wire, and (86) is far-infrared emitting ceramic baked on the surface. (37) indicates a lead wire. FIG. 11 shows a view seen from the L direction in FIG. 10.

Since this is a fired product, it is impossible to manufacture large products. Therefore, as shown in FIG. 12, a large number of them are lined up and connected in parallel.

(38) is the structural unit shown in FIG.

As shown above, commercially available products have complex structures and are expensive. On the other hand, the structure of the present invention is simple and the price is low. - To give an example, the product shown in FIG. 8 has a cost of about 30 yen/d per unit effective infrared radiation area, and the fired product shown in FIG. 10 has a cost of about 40 to 50 yen/i. On the other hand, in the case of the present invention shown in Fig. 1, it is 5 yen/d, and in the case shown in Fig. 3, it is 6 yen/d.
It is yen/ctj.

2) Commercially available products are heavy, have a large heat capacity, and have a long rise time, making fine temperature adjustment impossible. When the radiation temperature of the radiation surface is set to 300°C,
Its rise time is shown in Figure 8, about 25 minutes, and the first
The time shown in Figure 0 is approximately 8 minutes. On the other hand, in the case of the present invention shown in FIG. 1, it takes about 1 minute and 20 seconds, and the time shown in FIG. 3, which includes a carbon fiber bundle, takes about 1 minute. In Figure 13,
The rise time when the surface temperature is 800'C is shown for the case of the present invention. In the figure, 39...Product of the present invention shown in Fig. 1 40...Product of the present invention shown in Fig. 3 The product of the present invention is extremely light in weight and has a low heat capacity. Since it is small, the rise time is short and its thermal response is excellent.

8) Commercially available products use nichrome wire as the heating element, so they are prone to breakage, and if they break, they cannot be reused.

On the other hand, in the case of the present invention, since heat is generated over the entire surface, there is no disconnection, and even if a hole is formed in a part, there is no problem in use.

4) Since the planar far-infrared radiator of the present invention uses a hard mica plate, it can be used at a high temperature of 550°C.

It exhibits no distortion even after continuous use, and has excellent water resistance and electrical insulation properties.

5) The radiator of the present invention can be heated to 400°C to 400°C after bonding.
Since it is baked at a temperature of 50°C for about 10 minutes, the electrical resistance value is stable and does not change even after long-term use.

Next, the baking process will be explained. The conductive adhesive used in the present invention is prepared by dissolving fine particles of graphite in an aqueous solution of sodium silicate as a fixing agent and uniformly dispersing the mixture using an organic dispersant. After adhesion, the electrical resistance is high at first because the dispersant is mixed between the graphite particles, but when heated above 400°C, the dispersant completely decomposes and dissipates, resulting in a significant drop in electrical resistance and the ability to conduct electricity. The condition improves and becomes stable from then on. When bonded, the 0.50 α position becomes 0.05 after baking.
It becomes stable at Ω・α position.

Sodium silicate is 700°C or higher, graphite is 1000°C
It is stable in the above range.

[Brief explanation of drawings]

FIG. 1 shows an example of a planar far-infrared radiator of the present invention. FIG. 2 shows details of section A in FIG. 1. FIG. 3 shows an arrangement of carbon fiber bundles in addition to that shown in FIG. FIG. 4 shows details of section D in FIG. 3. FIG. 5 shows an infrared radiation section of a toaster as an embodiment of the present invention. FIG. 6 shows the voltage distribution of the radiator in FIG. 5. FIG. 7 shows a dryer as an embodiment of the invention. FIG. 8 shows an example of a commercially available planar far-infrared radiator. FIG. 9 shows a view seen from K in FIG. 8. FIG. 10 shows an example of a commercially available ceramic radiator. FIG. 11 shows a view from L in FIG. 10. FIG. 12 shows a case where the radiators shown in FIG. 10 are combined. FIG. 13 shows a graph of the rise time of the planar far-infrared radiator of the present invention. Second LjL

Claims (2)

[Claims] (1) A surface shape characterized by two hard mica plates with electrical terminals provided on both end faces and bonded together with a conductive adhesive made of graphite, with far-infrared emitting ceramics baked on one or both sides. Far-infrared emitter. (2) Two hard mica plates are provided with electrical terminals on both ends, and a good conductor of carbon fiber bundles is placed parallel to these terminals at regular intervals between the two terminals, and a conductive adhesive made of graphite is used. 1. A planar far-infrared radiator, characterized in that it is glued together and a far-infrared ray-emitting ceramic is baked on one or both sides thereof.