JPH06236796A - Induction heating coil, and heating equipment using this coil - Google Patents

Abstract

PURPOSE:To enlarge surface area to minimize a current carrying passage and its material loss, and minimize the resistance increase by surface thickness effect to enhance humidity distribution by using a rectangular conductor as an induction heating coil, and flatly or spirally arranging it. CONSTITUTION:A rectangular copper wire 1 17mm in width and 1mm in thickness, for example, is provided on a support plate 2 of glass fiber reinforced plastics to form an induction heating coil. The copper source 1 is concentrically and spirally formed, and this is adhered and fixed onto the support plate 2 by use of an adhesive. A body to be heated is arranged opposite to the coil, an AC voltage is applied between two terminals 3, 4, alternate magnetic force lines are generated in the form straddling them by rectangular copper wire groups 1c, 1d having the same current direction, and a spiral current is induced in the body to be heated. Thus, the mutual weakening of the alternate magnetic force lines is reduced, and the degree of freedom in heating condition and device design is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating coil using electromagnetic induction and a heating device using the coil.

[0002]

2. Description of the Related Art Induction heating type heating equipment has many advantages such as that the equipment itself hardly generates heat, and there is no fear of incomplete combustion or oxygen deficiency. Used in equipment, etc. Such conventional heating equipment,
For example, as shown in FIGS. 14 (a) and 14 (b), an induction heating coil b in which a conductor a such as a copper wire is spirally wound is used, and an alternating current is applied to the coil b to form an alternating magnetic field line. This alternating magnetic force line is passed through a conductive material such as an iron plate which is a heated object to generate an eddy current, and the heated object is directly heated by Joule heat due to the eddy current.
FIG. 15 shows an example in which such an induction heating method is applied to a large-sized commercial cooker. Note that this drawing schematically shows only the heating unit. In the example shown in FIG. 14, a large iron plate c for cooking is provided on the spiral induction heating coil b shown in FIG. 14 as a body to be heated. It is general to use a plurality of coils b.

[0003]

However, the conventional induction heating coil and heating device as described above have many problems as described below. In FIG. 16, FIG.
The cross-sectional structure of the conventional induction heating coil b is shown in the center line, and the cross marks and cross marks in the cross section of the copper wire a indicate that the flowing currents are in opposite directions. When an alternating current is passed through such a coil b, two types of alternating magnetic force lines d and e appear in opposite directions. Therefore, in the vicinity of the center of the coil b where these two types of alternating magnetic force lines d and e intersect more, the magnetic force lines d and e are in opposite directions, so they weaken each other, and effectively the outer peripheral portion of the coil b is However, there are no alternating magnetic field lines that are effective for heating, and as a result, the temperature distribution of the object to be heated becomes correspondingly annular. That is, effective heating can be obtained only in the annular portion near the outer peripheral portion of the coil b.

In order to avoid the influence of the annular temperature distribution, for example, in the example of the commercial cooker shown in FIG. 15, the temperature distribution is made uniform by moving the iron plate c which is the object to be heated. There is. Therefore, even if the stationary state is originally preferable, the iron plate c is forced to move, and the heating conditions and the degree of freedom in designing the apparatus become extremely small.

For uniform heating of the iron plate c, it is effective to heat the entire surface of the iron plate c with one coil.
In addition to significantly increasing the weight of the coil, a large coil must be wound into a rectangular shape, which is not practically applicable.

Further, a single wire or a twisted wire is used for the copper wire a. However, since there is an effective increase in resistance due to the skin effect peculiar to the alternating current, a thick wire is used for the single wire and a twisted wire is used for the twisted wire. Inevitably, many coils are used.
Was leading to an increase in weight. Since the skin effect is more remarkable as the frequency of the alternating current is higher, it may be considered to reduce it by lowering the frequency, but if the frequency is lower, the penetration depth of the eddy current generated in the heated object becomes deeper. Therefore, it is necessary to thicken the object to be heated and increase the input power accordingly, which also increases the weight of the coil b and the heating device. As a result, in addition to the increase in weight, the cost of the coil b and the heating equipment also increases.

As described above, in the conventional induction heating coil and the heating equipment using the same, there is a performance problem that a uniform temperature distribution of the object to be heated cannot be obtained, and the heating condition and the design of the apparatus are not free. There was a problem in terms of general versatility that the degree was reduced, and an economical problem that costs of coils and heating equipment increased.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the current situation, and makes the temperature distribution of a heated object uniform, has a high degree of freedom in heating conditions and device design, and has a lightweight coil. It is intended to provide an induction heating coil and a heating device using the coil, which can realize a reduction in the cost of the heating device.

According to the present invention, which solves the above-mentioned problems, a rectangular conductor wire is arranged in a plane as an induction heating coil, and it is considered to arrange it in a spiral shape. Also,
The flat conductor wire may be arranged on the support plates, sandwiched between the support plates, or embedded in the molded body.

The heating device comprises an induction heating coil in which flat conductor wires are arranged in a plane, and an object to be heated made of a conductor arranged so as to face the induction heating coil. It is also considered that the induction heating coil is used or that the object to be heated has a multilayer structure.

Another heating device comprises an induction heating coil in which flat conductor wires are arranged in a plane, and a non-heating member made of a non-magnetic material and arranged to face the induction heating coil. Therefore, it is considered to use a plurality of induction heating coils.

Further, as another heating device, an induction heating coil having a flat rectangular wire arranged in a plane, an object to be heated composed of a conductor arranged so as to face the induction heating coil, and supply and recovery of a heat-processed product. It is also considered that it is provided with a means for transporting a heated body for moving the heated body.

[0013]

Since the induction heating coil of the present invention uses the rectangular conductor, the resistance increase due to the skin effect can be compensated by increasing the width of the conductor. Then, it becomes possible to heat the entire surface of the object to be heated with one coil. Further, this coil can be applied to various conventional heating devices.

[0014]

EXAMPLES Next, details of the present invention will be described based on specific examples. 1 (a) and 1 (b) show an embodiment of the induction heating coil of the present invention, in which (a) is a plan view and (b) is a sectional view taken along line A-A in (a). There is. The example shown in the figure has a width of 17 m on a support plate 2 made of glass fiber reinforced plastic of 1090 mm × 500 mm
A rectangular copper wire 1 having a thickness of m and a thickness of 1 mm is provided to form an induction heating coil.

The rectangular copper wire 1 is concentrically formed in a spiral shape and is fixed to the support plate 2 by an adhesive.

An object to be heated is arranged so as to face the induction heating coil, and by applying an AC voltage between the two terminals 3 and 4, the rectangular copper wire group 1 having the same current direction.
Alternating magnetic field lines are generated in a manner of straddling c and 1d, and an eddy current is induced in the object to be heated. Also, 5 in the figure
11 is an imaginary line showing the outer shape of the conventional induction heating coil shown in the example of the commercial cooker in FIG. 11, and this embodiment has a size of 10 conventional coils. It means that there is. Therefore, as is clear from the range of the two rectangular copper wire groups 1c and 1d in which the current directions are the same, in this example, a substantially uniform temperature distribution can be obtained within the range of 10 conventional coils. Become. Further, since the space between the two rectangular copper wire groups 1c and 1d can be properly secured, the influence of the weakening of the alternating magnetic force lines can be reduced.

In order to make the temperature distribution more uniform, the AA cross section of FIG. 1 (a) has a structure as shown in FIG. It is also effective to make the distance nearer and farther at the outer circumference. On the contrary, it is also considered that the coil is far near the center of the coil and near the outer periphery. When combined with adjusting the distance to the object to be heated, it is more effective for improving the temperature distribution.

In the above example, the copper wire 1 is adhered to the support plate 2, but in addition to this, as shown in the sectional explanatory view of FIG. 3, the copper wire 1 is sandwiched between the support plates. You can also In the illustrated example, the copper wire 1 is sandwiched between the glass fiber reinforced plastic support plate 2 and the heat-resistant glass plate 6. By doing so, the copper wire 1 can be protected from dirt and scratches. You can

Further, as shown in the sectional view of FIG. 4, the copper wire 1 can be embedded in the molded body 7. By doing so, the copper wire 1 can be protected from dirt and scratches, handling becomes easy, and it contributes to improvement of workability during transportation and assembly. The molded body may be a material that is easy to mold and has heat resistance to some extent. For example, a fluororesin such as polytetrafluoroethylene can be used.

Further, the flat conductor wire may be embedded in the ceramic molded body. This can be manufactured by forming a conductor pattern made of metal powder as a rectangular conductor wire on a ceramic sheet before firing by a method such as printing, and further laminating similar ceramic sheets and firing the same. In this case, the resistance of the conductor pattern will be slightly higher, but it can be used for home appliances for low-power applications, and the coil itself has extremely high strength, so the coil will not be damaged even by heavy handling in the mass production process. .

Next, FIG. 5 shows an embodiment in which the heating device of the present invention is applied to a cooking device, as a sectional view for explanation. In the example shown in the figure, a heated body made of a conductor is arranged facing the induction heating coil, and the aluminum plate 14 is placed on the first shelf 15 provided on the stainless steel frame 13. An induction heating coil unit 17 in which a copper wire 1 is sandwiched between a glass fiber reinforced plastic support plate 2 and a heat-resistant glass plate 6 is further placed thereon, and placed on the second shelf 16 of the frame body 13. Is an object to be heated 10 made of SS41 mounted via a copper spacer 12.
Since SS41 is a magnetic material, the entire surface of the object to be heated is heated when the copper wire 1 is energized.

The object to be heated 10 may be appropriately provided with a positioning recess 11 for positioning a heated workpiece.

Further, as shown in FIG. 6, on both sides of the induction heating coil unit 17 in which the copper wire 1 is sandwiched between the two glass fiber reinforced plastic support plates 2 and 2, the object to be heated 10,
It is also possible to arrange each of 10 and heat two objects to be heated with one coil unit.

Since this drawing is an explanatory drawing, the illustration of other peripheral devices such as a power supply unit, an inverter, etc. is omitted.

As described above, when SS41 or the like is used for the object to be heated 10, rust on the surface is a concern. For example, as shown in FIG. 7, a corrosion resistant material such as aluminum is formed on the upper surface of the magnetic material base material 18 such as SS41. By providing 19, the surface can be prevented from corrosion such as rust.

The metal of the corrosion-resistant material 19 is preferably aluminum, stainless steel, or the like, and can be formed by laminating or spraying. In addition to metals, ceramics and the like are suitable, and these can also be formed by a bonding or coating technique.

Further, as used in a domestic cooker, a fluororesin such as polytetrafluoroethylene can be coated.

Further, as shown in a sectional view in FIG. 8, an object to be heated 10 made of a magnetic material such as SS41 is externally provided on the entire outer peripheral surface of the molded object 7 shown in FIG. It is also possible to combine and with.

This heated body 10 is a molded body 7 as shown in FIG.
It may be formed only on one side of.

Such a thing can be applied to, for example, an electric anchorage, a foot warmer, or a throw-in heater for boiling water.

Further, FIG. 10 shows another embodiment of the heating apparatus of the present invention as an explanatory sectional view thereof. This is one in which a non-heating body made of a non-magnetic material is arranged so as to face the induction heating coil, and it is shown as an example when applied to a domestic cooker. In the illustrated example, the induction heating coil unit 17 in which the copper wire 1 is embedded in the plate-shaped molded body 24 of polytetrafluoroethylene is placed and fixed on the shelf portion 23 of the synthetic resin main body container 20, and the main body container is further fixed. A ceramic upper plate 21 is provided on the upper surface 20. A general household commercial power source is used as a power source, and power is supplied to the induction heating coil unit 17 via the power source supply unit 22.

In such a cooking device, since the upper plate 21 is not heated, the iron pot or the like placed on it is heated.

Recently, in such a domestic cooker, it has been proposed that the heating area can be divided into two and the input power can be adjusted for each area. An example when applied to a cooking device for cooking is shown as a cross-sectional explanatory view. In this example, the copper wire 1a, 1b is embedded in the plate-shaped molded body 24 of polytetrafluoroethylene to be divided into two regions to form the induction heating coil unit 17, and two power supplies are provided for each of the two regions. Parts 22a, 22
Power is supplied via b.

For the upper plate 21, a metal material such as aluminum can be used in addition to ceramic.

Next, FIG. 12 shows a schematic diagram for explaining an embodiment in which the heating apparatus of the present invention is applied to a commercial cooking machine. In the illustrated example, the drive cylinder 30 and the idle cylinder 31
And a plurality of heated bodies 32 serving as a heated body transporting means.
While suspending the carrier 33 connected to the
The induction heating coil unit 17 is disposed in the lower part of the, and the heated body 32 moves on the induction heating coil unit 17 as the drive cylinder 30 rotates. The cooked food 34 to be cooked is supplied from the supply means 35 onto the object 32 to be heated, is heated and processed by the movement of the object 32 to be recovered, and is recovered by the recovery means 36.

Further, the induction heating coil unit 17 is provided with a power source section 37, an inverter 38, an impedance matching unit 39, etc., and a lower portion of the apparatus is provided with oiling and cleaning means 40 for the object 32 to be heated. It is also considered.

In addition to this, for example, it is possible to fix the object 32 to be heated and provide a cooking machine provided with only means for supplying and recovering the heat-processed material 34.

As another example, the invention can be applied to, for example, a fryer in which coils are arranged around an iron oil tank.
In this case, since the coil is made of a rectangular conductor, it can be easily applied to a complicated oil tank shape.

The operating frequency of the heating device as described above is 50 to 100 k from low frequencies of 50 and 60 Hz.
It is possible to appropriately select up to a high frequency of Hz or higher, and when a low frequency is used, the penetration depth of the eddy current becomes deep, so the thickness of the heated object may be increased.

The heating power corresponding to the heating power is adjusted by changing the applied voltage to adjust the strength of the magnetic field by the alternating magnetic force lines to change the magnitude of the eddy current generated in the object to be heated, or by an inverter. This can be performed by changing the frequency and changing the penetration depth of the eddy current generated in the object to be heated.

Further, the distance can be adjusted in the same manner by changing the distance between the coil and the object to be heated, and a distance adjusting function may be provided as a heating device.

Further, as heating power adjusting means other than these, for example, as shown in FIG. 13, two rectangular copper wires 50, 5 are used.
It is also possible to dispose two coils made of 1 in parallel, energize only one of the coils when weakening the heating power, and energize the two coils in the same phase when strengthening the heating power.

[0043]

As described above, since the induction heating coil of the present invention can have a large surface area by using the rectangular conductor, it is possible to realize a large-sized and light-weight coil with less material loss as a current path. it can. In addition, the effect of increased resistance due to the skin effect peculiar to alternating current can be compensated by increasing the surface area of the conductor, so that it is possible to increase the width of the conductor and reduce the thickness accordingly, for example, when increasing the frequency. In addition, it is possible to provide an induction heating coil that does not significantly increase the weight of the coil portion and is excellent in economic efficiency.

Since the size can be increased, the entire surface of the object to be heated can be heated by one coil, the temperature distribution that has been conventionally generated can be improved, and even a large object to be heated can be made uniform. It is possible to obtain a wide temperature distribution.

Further, arranging the rectangular conductors on a plane leads to thinning of the coil, and since it can be sandwiched between support plates or embedded in a plate-shaped integrally molded body, induction heating can be performed in any shape. It becomes possible to manufacture a coil for use.

Therefore, by using such an induction heating coil as a heating device, it is possible to provide an inexpensive heating device having a good temperature distribution, a large degree of freedom in heating conditions and device design. .

As described above, the present invention has an extremely wide range of use, and has problems in performance, versatility, and economical efficiency of the conventional induction heating coil and the heating equipment using the same. It is a solution at once.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an induction heating coil of the present invention, in which (a) is a plan view and (b) is a sectional view.

FIG. 2 is a sectional explanatory view showing another embodiment of the induction heating coil of the present invention.

FIG. 3 is a sectional explanatory view showing another embodiment of the induction heating coil of the present invention.

FIG. 4 is a sectional explanatory view showing another embodiment of the induction heating coil of the present invention.

FIG. 5 is a sectional explanatory view showing an embodiment of a heater using the induction heating coil of the present invention.

FIG. 6 is a cross-sectional explanatory view showing another embodiment of the heater using the induction heating coil of the present invention.

FIG. 7 is a cross-sectional explanatory view showing another example of the object to be heated used in the heater using the induction heating coil of the present invention.

FIG. 8 is a sectional explanatory view showing another embodiment of a heater using the induction heating coil of the present invention.

FIG. 9 is a cross-sectional explanatory view showing another embodiment of the heater using the induction heating coil of the present invention.

FIG. 10 is a sectional explanatory view showing another embodiment of the heater using the induction heating coil of the present invention.

FIG. 11 is a sectional explanatory view showing another embodiment of a heater using the induction heating coil of the present invention.

FIG. 12 is a schematic explanatory view showing an embodiment of a cooking machine using the induction heating coil of the present invention.

FIG. 13 is an explanatory view showing another embodiment of the induction heating coil of the present invention.

FIG. 14 is an explanatory view showing a conventional induction heating coil,
(A) is a plan view, (B) is a cross-sectional view taken along line BB of (A).

FIG. 15 is a perspective view showing a schematic structure when a conventional induction heating coil is applied to a cooking device.

FIG. 16 is an explanatory diagram showing a generation mode of alternating magnetic force lines in a conventional induction heating coil.

[Explanation of symbols]

 1, 1a, 1b, 50, 51 Flat copper wire 1c, 1d Flat copper wire group 2 Reinforced plastic support plate 3, 4 Terminal 5 External shape of coil 6 Heat resistant glass 7 Molded body 10, 32 Heated body 11 Recessed portion 12 Spacer 13 Frame 14 Aluminum Plates 15, 16, 23 Shelf 17 Induction Heating Coil Unit 18 Base Material 19 Corrosion Resistant Material 20 Main Body Container 21 Upper Plates 22, 22a, 22b Power Supply 24 Plate Formed Body 30 Drive Tube 31 Floating Tube 33 transport tool 34 heated workpiece 35 supplying means 36 collecting means 37 power supply section 38 inverter 39 impedance matching device 40 oiling and cleaning means

Claims (12)

[Claims] 1. An induction heating coil comprising flat conductor wires arranged in a plane. 2. A coil for induction heating according to claim 1, wherein the rectangular conductor wire is spirally arranged. 3. The induction heating coil according to claim 1, wherein the flat conductor wire is arranged on a support plate. 4. The induction heating coil according to claim 1, wherein the flat conductor wire is sandwiched between support plates. 5. The induction heating coil according to claim 1, wherein the flat conductor wire is embedded in a molded body. 6. A heating device comprising: an induction heating coil in which flat conductor wires are arranged in a plane; and a body to be heated made of a conductor arranged so as to face the induction heating coil. 7. The heating device according to claim 6, wherein a plurality of said induction heating coils are used. 8. The heating device according to claim 6, wherein the object to be heated has a multilayer structure. 9. A heating device comprising: an induction heating coil in which a flat conductor wire is arranged in a plane; and a non-heating body made of a non-magnetic material and arranged to face the induction heating coil. 10. The heating device according to claim 9, wherein a plurality of said induction heating coils are used. 11. An induction heating coil having a flat conductor wire arranged in a plane, a heated body made of a conductor arranged so as to face the induction heating coil, and a means for supplying and recovering a heated workpiece. Heating equipment. 12. The heating apparatus according to claim 11, further comprising a heated body transporting means for moving the heated body.