JPH08298180A - Heating device - Google Patents

Abstract

PURPOSE: To reduce a low frequency electromagnetic field so as to suppress an organism influence, by providing an insulating layer between a center conductor and a heating unit, and short-circuiting the other end of this center conductor and the other end of the heating unit. CONSTITUTION: A commercial AC current supplied from a power source is made to flow in a heating unit 3 from a center conductor 7 via a short-circuiting part 9 through a power supply switch 5 and a power supply cable 4. In this way, the heating unit 3 generates heat. Here, in an alternating current flowing in the center conductor 7 and the heating unit 3, the magnitude of the current becomes equal with a flow direction reverse to each other, and also in a low frequency electromagnetic field respectively generated by these currents, similarly the direction becomes reverse to each other further with equal intensity. As a result, a low frequency electromagnetic field corresponding to a frequency of the supplied AC current and a generation almost low frequency electromagnetic field are reduced. The center conductor 7 is coated with an insulating layer 8, and it is coated with the heating unit 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat generating device that suppresses the biological effect of low frequency electromagnetic fields.

[0002]

2. Description of the Related Art FIG. 13 shows, for example, US Pat.
FIG. 8 is a cross-sectional view showing the conventional heat generating device shown in No. 7, in which 6 is a power plug, 5 is a power switch, 4 is a power cable, and 1 is a rectifier for rectifying commercial AC current supplied. A circuit 3 is a heating element such as nichrome or conductive carbon fiber, and 2 is a blanket portion provided with the heating element 3.

Next, the operation will be described. Conventionally, 50 ~
It has been pointed out that a weak low-frequency electromagnetic field caused by a commercial alternating current of 60 Hz may promote the generation and growth of cancer. Therefore, it is necessary to reduce such a low-frequency electromagnetic field generated from a heating device such as an electric blanket that a living body such as a human body contacts.

Here, the frequencies of particular concern are 50 to 6
Since it is set to around 100 Hz centering on 0 Hz, the 60 Hz commercial AC current supplied from the power source is
The rectifier circuit 1 converts the current into a current having an AC component and a DC component of 120 Hz. The current rectified in this way flows through the heating element 3 to generate heat.
Therefore, in the blanket portion 2 with which the human body comes into contact, the low-frequency electromagnetic field component of 60 Hz, which is considered to have a bad effect on the living body, is reduced, so that the above-described biological influence can be suppressed. However, although it is said that there is no biological effect of the electromagnetic field due to the direct current, the danger of a low frequency electromagnetic field of about 100 to 200 Hz has been pointed out.

[0005] In addition, as a device having a bad influence on a living body such as a human body, an electric blanket, an electric carpet, an electric kotatsu,
VD used for heat generating devices such as electric foot warmers and OA equipment
Examples include T (image display terminal) devices and high-voltage power transmission lines. Regarding the biological effect of the low-frequency electromagnetic field, for example, “Nikkei Electronics” (Nikkei Inc., 19
February 17, 1992, pp. 236-240).

[0006]

Since the conventional heat generating device is constructed as described above, it is possible to reduce the low frequency electromagnetic field due to the commercial alternating current of 60 Hz, but it is still low frequency electromagnetic field of 120 Hz. However, there is a problem that the safety is not sufficiently established because it cannot be reduced.

The present invention has been made to solve the above problems, and not only a low frequency electromagnetic field by a commercial AC current of 50 to 60 Hz, but also a low frequency in a wide frequency range that adversely affects a living body. An object of the present invention is to obtain a heat generating device that can reduce the electromagnetic field more reliably.

[0008]

According to another aspect of the present invention, there is provided a heat generating device in which an insulating layer is provided between a central conductor and a heating element, and the other end of the central conductor and the other end of the heating element are short-circuited. It is the one.

According to a second aspect of the present invention, there is provided a heat generating device in which an insulating layer is provided between the heat generating element and the peripheral conductor, and the other end of the heat generating element and the other end of the peripheral conductor are short-circuited.

According to a third aspect of the present invention, there is provided a heat generating device in which an insulating layer is provided between two heating elements and the other ends of the two heating elements are short-circuited.

According to a fourth aspect of the present invention, there is provided a heat generating device in which a part of the heat generating element is formed of a conductor.

According to a fifth aspect of the present invention, there is provided a heat generating device in which an insulating layer for covering the heating element is covered with a magnetic shielding layer.

According to a sixth aspect of the present invention, there is provided a heat generating device in which an insulating layer which covers the peripheral conductor is covered with a magnetic shield layer.

According to a seventh aspect of the present invention, there is provided a heat generating device in which an insulating layer which covers the second heating element is covered with a magnetic shielding layer.

The heat generating device according to the invention of claim 8 is provided with a rectifier circuit for converting an alternating current into a direct current and supplying the direct current to the heating element.

[0016]

In the heat generating device according to the present invention, an insulating layer is provided between the central conductor and the heating element, and the other end of the central conductor and the other end of the heating element are short-circuited to generate heat from the central conductor. The current flowing through the body becomes the reciprocating current. In this way, the currents flowing through the central conductor and the heating element are in opposite directions and have the same magnitude. Therefore, the low-frequency electromagnetic fields generated by these currents are also in opposite directions and have the same magnitude. Will be the same. Therefore, these low-frequency electromagnetic fields cancel each other out, and not only the frequency of the alternating current supplied but also most of the low-frequency electromagnetic fields that are generated are reduced.

According to a second aspect of the present invention, in the heat generating device, an insulating layer is provided between the heat generating element and the peripheral conductor, and the other end of the heat generating element and the other end of the peripheral conductor are short-circuited. The current flowing through the conductor becomes a reciprocating current. Therefore,
The low-frequency electromagnetic fields generated by this round-trip current also have opposite directions and the same magnitude, canceling each other out, and not only the frequency of the supplied alternating current, but also the generated low-frequency electromagnetic field. Will be reduced.

In the heat generating device according to the third aspect of the invention, an insulating layer is provided between the two heat generating elements, and the other ends of the two heat generating elements are short-circuited so that the current flowing through the two heat generating elements is a reciprocating current. Becomes Therefore, the low-frequency electromagnetic fields generated by the round-trip currents also have opposite directions and the same magnitude, cancel each other out, and not only the frequency of the supplied alternating current, but also most of the generated low-frequency electromagnetic fields. The field is reduced. Further, since the reciprocating current flows only through the heating element, the heating capacity becomes large.

In the heat generating device according to the fourth aspect of the present invention, by forming a part of the heat generating element with a conductor, it is possible to eliminate heat generation in the conductor part.

According to the fifth aspect of the present invention, by covering the insulating layer that covers the heating element and the short-circuit portion with the magnetic shielding layer, low-frequency electric fields generated by the current flowing through the central conductor and the heating element are generated. A low-frequency magnetic field that cannot be removed even if they cancel each other out can be trapped by this magnetic shield layer.

In the heat generating device according to the invention of claim 6, by covering the insulating layer covering the peripheral conductor with a magnetic shielding layer, respective low-frequency electric fields generated by the electric current flowing through the heating element and the peripheral conductor cancel each other out. A low-frequency magnetic field that cannot be completely removed can be trapped by this magnetic shield layer.

The heat generating device according to the invention of claim 7 is the second aspect.
By covering the insulating layer that covers the above heating element with the magnetic shielding layer, the low-frequency electric fields generated by the currents flowing through the first heating element and the second heating element cannot be completely removed even if they cancel each other out. Low frequency magnetic fields can be trapped by this magnetic shield layer.

In the heat generating device according to the invention of claim 8, a rectifying circuit for converting an alternating current into a direct current and supplying the direct current to the heating element is provided, so that the alternating current component is removed from the current supplied to the heating portion. Therefore, the generation of the low-frequency electromagnetic field itself in the heat generating portion is reduced.

[0024]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view showing a heat generating device according to a first embodiment of the present invention. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and the explanation thereof will be omitted. 7 is a center conductor formed of a conductor such as copper wire, 8 is a heat-resistant insulating layer such as ceramics or resin, 9 is the other end of the center conductor 7 and the other end of the heating element 3 (the terminal of the power plug 6 is It is a short-circuit portion that short-circuits the end portion on the non-connected side. Although not shown in FIG. 1, the heating element 3 may be further covered with a heat resistant insulating layer.

Next, the operation will be described. A 50 Hz or 60 Hz commercial AC current supplied from the power source flows through the power switch 5 and the power cable 4 and from the central conductor 7 through the short-circuit portion 9 to the heating element 3, or vice versa. The central conductor 7 flows from the heating element 3 through the short-circuit portion 9 therethrough. In this way, the heating element 3 generates heat due to the current flowing through the heating element 3. here,
The round-trip currents flowing through the central conductor 7 and the heating element 3 have the same magnitude, but the flow directions are opposite to each other. Therefore, the low-frequency electromagnetic fields generated by these currents also have opposite directions and a large magnitude. Are the same. As a result, in the low-frequency electromagnetic field thus generated, components of the same magnitude but in opposite directions cancel each other out, and not only the low-frequency electromagnetic field corresponding to the frequency of the supplied alternating current, Most of the low frequency electromagnetic fields generated are reduced.

As described above, according to the first embodiment, since the low-frequency electromagnetic field is reduced by the mutual canceling effect, even if the human body comes into contact with the heat-generating blanket portion 2, it may cause cancer or growth of the living body. The adverse effect of is suppressed.

Example 2. In the first embodiment, the center conductor 7
2 is covered with the insulating layer 8 and the insulating layer 8 is further covered with the heating element 3. As shown in FIG. 2, the heating element 3 is covered with the insulating layer 8 and the insulating layer 8 is covered with the insulating layer 8. It may be covered with the peripheral conductor 10, and the same effect as that of the above-described first embodiment can be obtained.

Example 3. In the first embodiment, the center conductor 7
In the above, a case was shown in which the insulating layer 8 was covered with the insulating layer 8, and the insulating layer 8 was further covered with the heating element 3. As shown in FIG. 3, the heating element 3 (first heating element) was covered with the insulating layer 8. Further, the insulating layer 8 may be covered with another heating element 3 (second heating element), and the same effect as that of the first embodiment can be obtained. As described above, according to the third embodiment, since the heating element 3 is also used in the current-carrying portion covered with the insulating layer 8, the heat generation amount higher than that of the first embodiment can be obtained.

Example 4. Although the case where the insulating layer 8 is covered with the heating element 3 has been described in the first embodiment, FIG.
As shown in FIG. 5, a part of the heating element 3 may be made of a conductor, and the same effect as that of the first embodiment can be obtained. As described above, according to the fourth embodiment, since the conductor is used for the current-carrying portion of the folded portion of the blanket portion 2, there is no heat generation in the conductor portion, and there is less disconnection at the folded portion than in the first embodiment. it can.

Example 5. Although the magnetic shield layer is not provided outside the heating element 3 and the short-circuit portion 9 in the first embodiment, the magnetic shield layer may be provided as shown in FIG. That is, FIG. 5 is a cross-sectional view of a current-carrying portion that flows through the central conductor 7 and the heating element 3. In the figure, 11 is a heat-resistant insulating layer such as ceramics or resin coating the heating element 3, and 12 is this insulating layer 11. And a magnetic shield layer that covers the short circuit portion 9. Although not shown in FIG. 5, the magnetic shield layer 12 may be further covered with a heat resistant insulating layer.

As described above, according to the fifth embodiment, the low frequency magnetic field is shielded by the magnetic shield layer 12 and prevented from leaking to the outside. Therefore, the low frequency electromagnetic field is further reduced as compared with the first embodiment. it can. The magnetic shield layer 12 may be a layer containing a substance having a high magnetic permeability, and for example, a film coated with iron or ferrite is used.

Example 6. In the second embodiment, the surrounding conductor 1
0 and the case where the magnetic shield layer is not provided outside the short-circuit portion 9 is shown, but a magnetic shield layer may be provided as shown in FIG. Note that FIG. 6 is a cross-sectional view of an energized portion that flows through the heating element 3 and the peripheral conductor 10. As described above, according to the sixth embodiment, it is possible to prevent the low-frequency magnetic field from being shielded by the magnetic shield layer 12 and leaking to the outside, so that the low-frequency electromagnetic field can be further reduced as compared with the second embodiment.

Example 7. In the third embodiment, the case where the magnetic shield layer is not provided outside the heating element 3 that covers the insulating layer 8 and the short-circuit portion 9 has been described. However, as shown in FIG. 7, a magnetic shield layer may be provided. Good. Note that FIG. 7 is a cross-sectional view of an energized portion that flows through the two heating elements 3. As described above, according to the seventh embodiment, the low frequency magnetic field is shielded by the magnetic shield layer 12 and prevented from leaking to the outside, so that the low frequency electromagnetic field can be further reduced as compared with the third embodiment.

Example 8. FIG. 8 is a sectional view showing a heat generating device according to an eighth embodiment of the present invention. In the figure, 20 is a rectifying circuit for converting an alternating current into a direct current. The rectified current converted into the component and converted in this way is applied to the heating element 3
Is supplied to. Therefore, the electromagnetic field generated by this rectified current is also a DC electromagnetic field and contains almost no AC component. As shown in FIG. 8, for example, a smoothing circuit including smoothing capacitors 17 and 18 and a smoothing coil 19 is provided between the rectifier circuit 20 and the heating element 3 to reduce the dip of the rectified current. The AC component can be further removed.

As described above, according to the eighth embodiment, since the energizing current can be converted into almost direct current by the rectifier circuit 20, the generation of the low frequency electromagnetic field can be reduced as compared with the first embodiment. Needless to say, even if the low-frequency electromagnetic field is slightly generated, the respective low-frequency electromagnetic fields can be reduced by mutually canceling out the respective electromagnetic fields generated by the current flowing through the central conductor 7 and the heating element 3.

Example 9. In the above-described first embodiment, the short-circuit method in the short-circuit portion 9 is shown as shown in FIG. 1 in which one end of the heating element 3 and the central conductor 7 are connected by a single wire. In addition, the heating element 3 and the central conductor 7 may be connected by a plurality of radial short-circuit lines symmetrically arranged with respect to the central conductor 7, and the same effect as that of the above-described first embodiment is obtained.

In FIG. 9, 13 is a radial short-circuit wire which is arranged symmetrically with respect to the central conductor 7 and short-circuits the central conductor 7 and the heating element 3, and 14 is a short-circuit board in which the radial short-circuit wire 13 is wired. Is. The short-circuit board 14 is attached to the heating element 3 so that the radial short-circuit wires 13 are connected to the central conductor 7 and the heating element 3, respectively.

Example 10. In the first embodiment described above, the short circuit portion 9
As shown in FIG. 1, the short circuit method in Fig. 1 shows a case where one end of the heating element 3 and the central conductor 7 are connected by a single wire. However, as shown in Fig. 10, the inner surface is covered with a metal layer. The heating element 3 and the central conductor 7 may be connected by a short-circuit board, and the same effect as that of the above-described first embodiment is obtained.

In FIG. 10, reference numeral 15 is a short-circuit board. The inner surface of the short-circuit board 15 is covered with a metal layer as shown in FIGS. 11 and 12, for example. In FIGS. 11 and 12, 16
Is a metal layer.

Example 11. In the above Examples 1 to 10, the case where the heat generating device is an electric blanket has been described, but even when the heating element is an electric carpet, an electric kotatsu, an electric foot warmer, or the like, the same effects as those in Examples 1 to 10 above. It goes without saying that you can get

[0041]

As described above, according to the invention of claim 1, the insulating layer is provided between the central conductor and the heating element, and the other end of the central conductor and the other end of the heating element are short-circuited. Since it is configured, the current flowing through the center conductor and the heating element can be a reciprocal current, and the low frequency electromagnetic fields generated by this reciprocal current cancel each other out, so that the low frequency electromagnetic field can be reduced and the low frequency electromagnetic field can be reduced. It has the effect of suppressing the biological effects of the world.

According to the second aspect of the present invention, the insulating layer is provided between the heating element and the peripheral conductor, and the other end of the heating element and the other end of the peripheral conductor are short-circuited. The current flowing in the surrounding conductor can be a reciprocating current, and the low-frequency electromagnetic fields generated by the reciprocating current cancel each other out. As a result, the low-frequency electromagnetic field can be reduced and the biological effect of the low-frequency electromagnetic field can be suppressed. effective.

According to the third aspect of the present invention, since the insulating layer is provided between the two heating elements and the other ends of the two heating elements are short-circuited, the current flowing through the two heating elements is reduced. It can be a round-trip current, and as a result of the low-frequency electromagnetic fields generated by this round-trip current canceling each other,
There is an effect that the low frequency electromagnetic field can be reduced and the biological effect of the low frequency electromagnetic field can be suppressed. Further, since the reciprocating current is configured to flow only in the heating element, there is also an effect that a high heating capacity can be obtained in the blanket portion.

According to the invention of claim 4, since a part of the heating element is constituted by a conductor, it is possible to eliminate heat generation in the conductor part, and as a result, disconnection at the folded portion of the blanket part is achieved. There is an effect that can be reduced.

According to the fifth aspect of the present invention, since the insulating layer for covering the heating element is covered with the magnetic shield layer, a low frequency magnetic field which cannot be completely removed by the mutual cancellation effect is provided by the magnetic shield layer. As a result of being trapped, the low-frequency magnetic field is further reduced, and the biological effect of the low-frequency electromagnetic field can be suppressed.

According to the sixth aspect of the invention, since the insulating layer that covers the peripheral conductor is covered with the magnetic shield layer, a low-frequency magnetic field that cannot be removed even by the mutual cancellation effect is provided by the magnetic shield layer. As a result of being trapped, the low-frequency magnetic field is further reduced, and the biological effect of the low-frequency electromagnetic field can be suppressed.

According to the invention of claim 7, since the insulating layer for covering the second heating element is covered with the magnetic shielding layer, the low frequency magnetic field which cannot be removed even by the mutual cancellation effect is generated by this magnetic field. As a result of being able to be trapped by the shielding layer, the low-frequency magnetic field is further reduced, and the biological effect of the low-frequency electromagnetic field can be suppressed.

According to the eighth aspect of the invention, since the rectifying circuit for converting the alternating current into the direct current and supplying the direct current to the heating element is provided, the rectifying current is supplied to the heat generating portion. Therefore, as a result of the generation of the low frequency electromagnetic field itself in the blanket portion being reduced, the low frequency electromagnetic field is further reduced, and the biological effect of the low frequency electromagnetic field can be suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a heat generating device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a heat generating device according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a heat generating device according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a heat generating device according to Embodiment 4 of the present invention.

FIG. 5 is a cross-sectional view showing a central conductor of a heat generating device according to a fifth embodiment of the present invention and an energized portion flowing through a heat generating body.

FIG. 6 is a cross-sectional view showing a heating element of a heating device according to a sixth embodiment of the present invention and an energized portion flowing through a peripheral conductor.

FIG. 7 is a cross-sectional view showing a current-carrying portion that flows through two heating elements of a heating device according to a seventh embodiment of the present invention.

FIG. 8 is a sectional view showing a heat generating device according to an eighth embodiment of the present invention.

FIG. 9 is a perspective view showing a short circuit portion of a heat generating device according to a ninth embodiment of the present invention.

FIG. 10 is a perspective view showing a short circuit portion of a heat generating device according to a tenth embodiment of the present invention.

FIG. 11 is a plan view showing an inner surface of a short-circuit board of a heat generating device according to a tenth embodiment of the present invention.

FIG. 12 is a plan view showing an inner surface of a short-circuit board of a heat generating device according to a tenth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a conventional heat generating device.

[Explanation of symbols]

3 heating element, 6 power plug, 7 center conductor, 8, 11
Insulation layer, 9 short-circuited parts, 10 surrounding conductors, 12 magnetic shielding layer, 20 rectifier circuit.

Claims (8)

[Claims] 1. A power plug having two terminals connected to an AC power source, a center conductor having one end connected to one terminal of the two terminals of the power plug, and covering the center conductor. One end is connected to the insulating layer and the other terminal of the two terminals of the power plug, while the heating element that covers the insulating layer, the other end of the center conductor, and the other end of the heating element are connected to each other. A heat generating device having a short-circuited portion that short-circuits. 2. A power source plug having two terminals connected to an AC power source, a heating element having one end connected to one terminal of the two terminals of the power source plug, and covering the heating element. One end is connected to the insulating layer and the other terminal of the two terminals of the power plug, while the peripheral conductor covering the insulating layer, the other end of the heating element and the other end of the peripheral conductor are connected to each other. A heat generating device having a short-circuited portion that short-circuits. 3. A power plug having two terminals connected to an AC power source, and a first heating element having one end connected to one of the two terminals of the power plug.
One end of the insulating layer covering the first heating element and the other terminal of the two terminals of the power plug are connected, while the second heating element covering the insulating layer is connected to the second heating element. A heating device comprising: the other end of the first heating element and a short-circuit portion that short-circuits the other end of the second heating element. 4. The heat generating device according to claim 1, wherein a part of the heating element is made of a conductor. 5. The heat generating device according to claim 1, further comprising an insulating layer that covers the heating element and a magnetic shielding layer that covers the insulating layer. 6. The heat generating device according to claim 2, further comprising: an insulating layer that covers the peripheral conductor, and a magnetic shielding layer that covers the insulating layer. 7. An insulating layer covering the second heating element,
The heating device according to claim 3 or 4, further comprising a magnetic shield layer that covers the insulating layer. 8. The rectifier circuit for converting an alternating current input from the power plug into a direct current and supplying the direct current to the heating element, according to any one of claims 1 to 7. The heat generating device according to item 1.