JPS636876Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electric heater, and particularly to an electric heater using high-frequency induction heating.

As is well known, it is known that an object emits electromagnetic waves from its surface depending on its temperature. The radiant energy density E〓 of the electromagnetic waves emitted at this time is
It depends only on the wavelength λ of the electromagnetic wave and the temperature (absolute temperature) T of the object, and is expressed by the well-known Planck radiation equation, E=8πhc/λ ⁵・1/exp(hc/kTλ)−1. Here, h is Planck's constant, k is Boltzmann's constant, and c is the speed of light. Generally, this radiated electromagnetic wave is in the infrared range (wavelength ranges from 0.75 μm to several mm), and as shown in Figure 6, the peak of the radiant energy density E〓 is at a temperature T
The higher the temperature T, the shorter the wavelength λ, and conversely, the lower the temperature T, the longer the wavelength λ. The fact that objects emit electromagnetic waves is well known, for example because wave cloth detects infrared rays emitted by the human body and attacks people. In this way, objects such as the human body emit electromagnetic waves, or infrared rays, to the outside according to their temperature, but on the other hand, infrared rays have a large thermal effect, and are also called heat rays.
Absorbed in objects such as the human body. The propagation range of the infrared rays absorbed at this time is remarkable mainly in the range of 5 μm to 20 μm. As mentioned above, when the temperature T is high, the peak of the radiant energy density E is on the short wavelength side, so the amount of energy that is not absorbed increases. Therefore, the maximum temperature should be around 400℃, preferably 260℃.
Good condition.

Electric kotatsus, electric stoves, and the like have been known as electric heaters that utilize the properties of infrared rays. However, this type of electric heater is configured to pass current directly to the heating element, so
It is necessary to apply an insulator to the heating element, and when the heater gets old, there is a risk that the insulator may peel off and cause an electric shock.

[Conventional technology]

Therefore, the present invention was proposed in a patent application filed on September 11, 1980, in order to eliminate the above-mentioned drawbacks.
No. 188895, titled "Far-infrared heater", has already proposed an electric heater that applies high-frequency induction heating.

This proposed electric heater consists of a high-frequency current generator that generates a high-frequency current, a high-frequency magnetic field generator consisting of one spirally wound induction coil that generates a high-frequency magnetic field by the high-frequency current, and a high-frequency magnetic field generator that generates a high-frequency magnetic field using the high-frequency current. It has an infrared ray emitting member including an iron-based metal magnetic material that is heated by eddy current loss and hysteresis loss caused by electromagnetic induction due to changes in the magnetic field and emits infrared rays corresponding to the heated temperature.

Fig. 4 is a block diagram showing the high frequency induction heating device used in this electric heater, and Fig. 5 shows the high frequency magnetic field generator and the infrared radiation member which is the heated object of the high frequency induction heating device shown in Fig. 4. FIG. 2 is a diagram showing the arrangement relationship between the two, in which a is a front view, b is a cross-sectional view taken along line B-B' of a, and c is a diagram showing the strength of the magnetic field.

As shown in FIG. 4, the conventional high-frequency induction heating device 10' includes a high-frequency current oscillator 11, a power amplifier 12 connected to the high-frequency current oscillator 11, and a high-frequency magnetic field generator 13 connected to the power amplifier 12. ', and the high frequency magnetic field generator 13' is
It consists of a single spirally wound induction coil.

Referring to FIG. 5, the high frequency magnetic field generator 1
3' and the infrared radiation member 20, so that their surfaces are parallel to each other and their centers coincide.
located close together.

In such a configuration, the current I generated from the high frequency current generator 11 at a certain time is the fifth
In the direction of the arrow in Figure a, in other words, in the direction indicated by and ○• in Figure 5b (here, indicates the direction downward from the top of the paper, and ○ indicates the direction upward from the bottom of the paper). Suppose it was flowing. At this time, the magnetic field generated by the high frequency magnetic field generator 13' is as shown in FIG.
The strength is strongest near the center, below the top of the page, that is, in the direction, and near the periphery, above the bottom of the page, ie, in the ◯ direction, and its strength is expressed as shown in Figure 5c. Here, the dotted line in FIG. 5b indicates the direction in which the magnetic field flows.

In this way, a magnetic field, that is, magnetic flux, passes through the inside of the infrared radiating member 20, but at this time, due to electromagnetic induction, an induced current, that is, eddy current flows in a direction that prevents changes in the magnetic flux, and the infrared rays emitted by the ferromagnetic material Eddy current losses and hysteresis losses occur in the member 20, and the infrared radiating member 20 is heated. At this time, infrared rays corresponding to the heated temperature are emitted from the surface of the infrared radiating member 20.

[Problem that the invention attempts to solve]

In such a conventional structure, as shown in FIG. 5c, the magnetic flux passing through the infrared radiation member 20 is large only near its center, and the infrared radiation member 20 is heated only at its center. Therefore,
The infrared ray radiating member 20 has the disadvantage that its temperature distribution is non-uniform and the degree of expansion differs at each point, resulting in warpage.

[Means for solving problems]

The electric heater according to the present invention includes a high-frequency current generating means, a high-frequency magnetic field generating means for generating a high-frequency magnetic field by the high-frequency current generated from the high-frequency current generating means, and an electromagnetic field generated by the high-frequency magnetic field generated from the high-frequency magnetic field generating means. In an electric heater comprising a radiation means that is heated by energy loss caused by induction and emits infrared rays corresponding to the heating temperature, the high-frequency magnetic field generating means is configured such that the directions of the generated high-frequency magnetic fields are opposite to each other. at least 2 of the directions
The plurality of regions are divided into two regions, and the directions of high-frequency magnetic fields generated from inside the adjacent divided regions are opposite to each other, and the directions of the high-frequency currents flowing around the divided regions are all in the same rotational direction. A coil is arranged to cover the radiation means.

[Effect]

When multiple coils are arranged as a high-frequency magnetic field generating means in this way, the generated high-frequency magnetic field is not concentrated in one place but is dispersed, so that the radiation means heated thereby is heated uniformly. This makes it possible to prevent the radiation means from warping. Furthermore, each coil is arranged so that the direction of the high-frequency magnetic field generated by the adjacent segmented regions is opposite, and the direction of the high-frequency current flowing around the segmented regions is in the same rotational direction. It is possible to prevent the high frequency magnetic field generated in the divided area from being canceled by the high frequency magnetic field generated in other divided areas, and the high frequency magnetic field is efficiently generated.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a block diagram showing the configuration of an embodiment of the high frequency induction heating device used in an electric heater according to the present invention, and Fig. 2 shows the high frequency magnetic field generator of the high frequency induction heating device shown in Fig. 1. Figures illustrating the arrangement of infrared radiation members, a is a front view, and b is a side view of a.
It is a sectional view seen from line A'.

The high-frequency induction heating device 10 of the present invention includes a high-frequency current oscillator 11 and a power amplifier 1 connected to the high-frequency current oscillator 11, as shown in FIG.
2 and a high frequency magnetic field generator 13 connected to the power amplifier 12, but this high frequency magnetic field generator 13 is different from a conventional high frequency magnetic field generator 13', as will be described later.

Referring to FIG. 2, the high frequency magnetic field generator 13 according to the present invention has a plurality of coils arranged as shown in the figure to cover the infrared radiation member 20, and arranged close to each other so that their surfaces are parallel to each other. However, the generated high-frequency magnetic field is divided into five elongated regions. Here, these five divided areas are defined as area ~
Let's call it a region.

Now, assume that the current I generated from the high frequency current oscillator 11 is flowing in the direction of the arrow, as shown in FIG. 2a. At this time, in FIG. 2a, the direction of the current flowing through the conductors around the area is all clockwise, all the area is counterclockwise, all the area is clockwise, the area is all counterclockwise, and the area is all clockwise. Therefore, in FIG. 2a, the direction of the magnetic field generated at that time is a direction below the top of the page (hereinafter referred to as the "direction") inside the area, and a direction above the bottom of the page (hereinafter referred to as ○) inside the area. ), inside the area is the direction, inside the area is the ○ direction, and inside the area is the direction. That is, 5 surrounded by coils.
In the two regions, the centers of each region are shifted from each other, the directions of the magnetic fields passing through the interior of adjacent regions are opposite to each other, and the current direction flowing through the coils around each region is all in the same rotation direction. .

Also, the magnetic field (magnetic flux) generated at this time is caused by the infrared radiation member 20, as shown by the dotted line in FIG. 2b.
In the infrared radiation member 20, an induced current flows in a direction that prevents changes in the magnetic flux due to electromagnetic induction, and heat is generated due to energy loss due to eddy current loss and hysteresis loss. The infrared radiating member 20 emits infrared rays corresponding to the heated temperature, thereby warming a radiated object such as a human body in the vicinity thereof. The heated temperature at this time is
As mentioned above, the temperature is chosen to be approximately 260°C. but,
It is not limited to this temperature.

As shown in FIG. 2, an infrared radiation member 20
Since the magnetic flux passing through the infrared radiation member 20 is dispersed without being concentrated in one place, the infrared radiation member 20 is heated uniformly, and warping as in the conventional case can be prevented. In addition, as mentioned above, the directions of the magnetic fields passing through the interior of adjacent regions are opposite to each other, and the current direction flowing through the coils around each region is all in the same rotational direction, so the magnetic field is not concentrated as in the conventional case. It is possible to prevent magnetic fields from causing or canceling each other out, and it is possible to efficiently generate a magnetic field. In addition, in Fig. 2 b, and ○・
indicates the direction of the current, ◯ indicates the direction below the top of the paper, and ◯ indicates the direction above the bottom of the paper.

FIG. 3 is a front view showing another embodiment of the arrangement relationship between the high frequency magnetic field generator and the infrared radiation member of the high frequency induction heating device according to the present invention. In this embodiment, the high frequency magnetic field generated by the high frequency magnetic field generator 13 is divided into 3×7=21 regions. In this embodiment as well, the high frequency magnetic field generator 13 covers the infrared radiation member 20 and is disposed close to each other so that their surfaces are parallel to each other. Furthermore, in the case of this embodiment as well, the center positions of the regions surrounded by the coils are shifted from each other, and the directions of the magnetic fields passing through the interiors of adjacent regions are opposite to each other, and the magnetic fields flow through the coils around each region. All current directions are the same direction of rotation. Therefore, it is clear that this embodiment has the same effect as the embodiment shown in FIG.

Note that the number of turns of the coil around the divided area is arbitrarily and appropriately selected.

Furthermore, although all of the embodiments described above use only one conductive wire, it goes without saying that a plurality of conductive wires may be used for each area or for a set of multiple areas.

Further, in the above-described embodiment, the infrared radiation member is provided on only one side of the high frequency magnetic field generator, but it is of course possible to provide the infrared radiation member on both sides of the high frequency magnetic field generator. It is. Furthermore, the infrared radiation member and the high frequency magnetic field generator are not limited to a planar shape, but may have other shapes such as a spherical surface.

[Effect of idea]

As is clear from the above description, according to the present invention, the high-frequency magnetic field generating means covering the infrared ray emitting means is divided into at least two regions in which the directions of the generated high-frequency magnetic fields are opposite to each other, and the divided regions are adjacent to each other. The plurality of coils are arranged so that the directions of the high-frequency magnetic fields generated from inside the section are opposite to each other, and the directions of the high-frequency currents flowing around the divided areas are all in the same rotational direction. It has the advantage that it can be heated uniformly, prevent warping, and efficiently generate a high-frequency magnetic field.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the high frequency induction heating device used in an electric heater according to the present invention, and Fig. 2 shows the high frequency magnetic field generator of the high frequency induction heating device shown in Fig. 1. FIG. 3 is a front view showing another embodiment of the arrangement relationship between the high frequency magnetic field generator and the infrared radiation member of the high frequency induction heating device according to the present invention, and FIG. 4 is a diagram showing the arrangement relationship of the infrared radiation member. A block diagram showing the configuration of a high-frequency induction heating device that uses a conventional electric heater, and FIG. 5 shows the arrangement relationship between the high-frequency magnetic field generator and the infrared radiation member of the high-frequency induction heating device shown in FIG. FIG. 6 is a diagram showing an example of the relationship between radiant energy density and wavelength when temperature is used as a parameter. 10... High frequency induction heating device, 13... High frequency magnetic field generator, 20... Infrared radiation member.

Claims (1)

[Scope of utility model registration request] A high-frequency current generating means, a high-frequency magnetic field generating means for generating a high-frequency magnetic field by the high-frequency current generated by the high-frequency current generating means, and heating due to energy loss caused by the electromagnetic induction effect of the high-frequency magnetic field generated from the high-frequency magnetic field generating means. and a radiation means for emitting infrared rays corresponding to the heating temperature, wherein the high frequency magnetic field generating means is divided into at least two regions in which the directions of the generated high frequency magnetic fields are opposite to each other. , a plurality of coils rotate the radiation so that the directions of high-frequency magnetic fields generated from inside the adjacent divided regions are opposite to each other, and the directions of the high-frequency currents flowing around the divided regions are all in the same rotational direction. An electric heater characterized by being arranged so as to cover the means.