WO2009130761A1 - Induction heating apparatus, warm air generator, and hand drying apparatus - Google Patents

Abstract

An induction heating apparatus has a coil, one or more first heating panels made of nonmagnetic conductors and each forming a channel between the coil and itself, second heating panels made of magnetic conductors and each forming a channel between each first heating panel and itself, and a high-frequency power supply for supplying a high-frequency current to the coil. The first heating panels have slits extending substantially in the same direction as those of the magnetic fluxes occurring at the coil. Thus, a heat transmission area is increased by a simple structure to realize the induction heating apparatus capable of efficiently heating a fluid such as a gas, and a liquid.

Description

Induction heating device, hot air generator using the same, and hand dryer

The present invention relates to an induction heating apparatus that heats a fluid such as a gas or a liquid using induction heating.

Several induction heating apparatuses that heat a metal by induction heating and heat a fluid such as a gas or a liquid in contact with the heated metal have been proposed. In such an induction heating device, the metal surface in contact with the fluid becomes the heat transfer surface, and therefore, in order to realize efficient heat transfer to the fluid, the area of the heat transfer surface is configured to be as large as possible. It was.

For example, in the induction heating device described in Patent Document 1, a coil is formed by winding a lead wire such as a litz wire around the outer periphery of a cylindrical case made of a non-magnetic material such as ceramic, and a heating element is provided inside the cylindrical case. The heating element is inductively heated by flowing a high-frequency current through the coil, and the fluid is heated by passing the fluid through the inside of the case in which the heating element is stored (Patent Document 1, FIG. 1). The heating element is formed by alternately laminating a flat first sheet and a corrugated second sheet made of SUS447J1 defined in JIS (Japanese Industrial Standard) standard of ferritic stainless steel having magnetism. It is comprised so that the area of a heat-transfer surface may be enlarged (FIG. 2). The first sheet and the second sheet are welded by spot welding and are electrically connected. The surface of the second sheet is provided with holes for generating a turbulent fluid flow. In the induction heating apparatus configured as described above, when a high-frequency current is passed through the coil, the sheet material is laminated so as to have a space and can be electrically conducted, and the current crossing the peripheral portion from the current along the peripheral portion. Is formed in a shape that facilitates flow, so that a heat transfer area can be secured, and the heating element in the central part inside the case generates more heat than the peripheral part. Since the fluid passing through the case flows more easily in the central portion than in the peripheral portion, it is uniformly heated by the heating element that generates heat in the central portion.

On the other hand, although not an induction heating device for heating a fluid, for example, Patent Document 2 discloses an induction heating device that heats a metal pan by induction heating for the purpose of cooking. In such an induction heating apparatus for cooking purposes, the buoyancy generated when a pan made of a material having a high electrical conductivity such as aluminum or copper is heated by induction heating in order to make the temperature at the bottom of the pan uniform or reduced. In order to do this, it is known to provide an electric conductor made of aluminum or copper between the induction heating coil and the pan.

In the induction heating device described in Patent Document 2, a conductive plate in which six slits are radially formed from the center hole to the peripheral part between a coil for induction heating and a SUS-based magnetic container that is an object to be heated. Is used. One of the slit portions is connected to the outer peripheral edge of the conductive plate. In such a configuration, when a high-frequency current is passed through the induction heating coil, the induction current flows in the direction around the conductive plate. However, the induction current is blocked by the slit connecting the outer peripheral edge and the center hole, and is used for induction heating. The direction is changed in the same direction as the high-frequency current flowing in the coil, and flows along a slit that is not connected to the center hole and the outer peripheral edge. As a result, since the induction current near the center of the conductive plate flows in the same direction as the high-frequency current flowing through the induction heating coil, the magnetic field near the center of the conductive plate is strengthened, and the temperature difference in each part of the bottom surface of the heated object is reduced. .

Further, for example, Patent Document 3 discloses an induction heating device that induction-heats an object to be heated made of aluminum, copper, or a low magnetic permeability material having an electric conductivity equal to or higher than that for cooking. In this induction heating apparatus, an electric conductor such as aluminum is provided between a heating coil for induction heating and an object to be heated. In such an induction heating apparatus, since the magnetic field generated from the heating coil is linked to the electric conductor and the object to be heated, an induction current is generated in both, and the magnetic field generated by the induction current induced in the electric conductor and the object to be heated are heated. An induced current flows through the electric conductor and the object to be heated so that a superimposed magnetic field of the magnetic field generated by the current induced in the object prevents a change in the magnetic field generated by the heating coil. In other words, since the distribution of current induced in the object to be heated changes due to the generation of induced current in the electrical conductor, the change in the current distribution increases the equivalent series resistance of the heating coil and obtains the same output. In this case, the current value flowing through the heating coil can be reduced, the buoyancy acting on the object to be heated is reduced, and the electric conductor acts on the object to be heated by sharing a part of the buoyancy acting on the object to be heated. The buoyancy is reduced. In addition, in order to limit the distribution of the induced current flowing around the electric conductor in parallel with the direction in which the heating coil current flows, a cutout, an opening, and a slit are provided in the electric conductor, and the amount of heat generated by the electric conductor Is suppressed and the object to be heated is heated. However, in the case of an iron-based object to be heated, an effect of increasing the equivalent series resistance of the heating coil by inserting an electric conductor is hardly obtained.

JP-A-8-264272 JP 7-211444 A JP 2003-264054 A

In such an induction heating device shown in Patent Document 1, since a sheet of ferritic stainless steel having flat and corrugated magnetism is laminated and stored inside the cylindrical case, these The heat transfer area can be increased by heating the stainless steel sheet, but in order to cause the induced current to flow through the stainless steel sheet, the flat sheet and the corrugated sheet are welded by spot welding etc. As a result, the manufacturing cost for spot-welding a large number of stainless steel sheets increases, the spot-welded part must be reliably conducted, and the cost required for maintaining reliability also increases. There was a problem.

On the other hand, the induction heating device disclosed in Patent Document 2 or 3 is not designed to heat a fluid such as a gas or a liquid in the first place, and therefore cannot efficiently heat the fluid. Also, even if it is used for fluid heating, the amount of heat generated by the electrical conductor provided between the coil for induction heating and the object to be heated is suppressed as small as possible, and the temperature distribution of the object to be heated is made uniform or efficiently heated. In order to do this, the electrical conductor is provided with slits, so in terms of the heat transfer area for fluid heating, the main heat transfer surface is a heated object such as a pan bottom, and the electric conductor is almost the heat transfer surface. It does not contribute.

The present invention has been made to solve the above-described problems, and an induction heating apparatus that can increase the heat transfer area with a simple structure and efficiently heat a fluid such as a gas or a liquid. It is intended to be realized.

An induction heating apparatus according to an embodiment of the present invention includes a coil and a nonmagnetic conductor, and includes at least one first heating plate that forms a flow path between the coil and the conductor, A second heating plate that forms a flow path between the first heating plate and a high-frequency power source that supplies a high-frequency current to the coil, wherein the first heating plate has a direction of magnetic flux generated by the coil; It has a slit extending in substantially the same direction.

According to the present invention, since the magnetic flux that has passed through the slit of the first heating plate reaches the second heating plate arranged on the outer side, all the heating plates are induction-heated to increase the heat transfer area. Thus, the present invention has a remarkable effect that the fluid can be heated.

It is a perspective view of the induction heating apparatus of Embodiment 1 which concerns on this invention. It is a disassembled perspective view of the induction heating apparatus shown in FIG. (A) And (b) is the top view and sectional drawing of a coil shown in FIG. 1, Comprising: The direction of the magnetic flux produced from a coil is shown. (A) is a perspective view of the first heating plate shown in FIG. 1, and (b) to (c) are cross-sectional views of the induction heating device shown in FIG. 1, showing the state of magnetic flux. It is side surface sectional drawing of the warm air generator using the induction heating apparatus shown in FIG. It is a perspective view of the perforation heating plate used as a comparative example of the first heating plate. It is a graph which shows the relationship between the aperture ratio of a 1st heating plate (SUS304), and the temperature rise of each part of an induction heating apparatus. It is a graph which shows the relationship between the aperture ratio of a 1st heating plate (aluminum), and the temperature rise of each part of an induction heating apparatus. It is a perspective view of the induction heating apparatus by Embodiment 2 of this invention. (A) And (b) is a perspective view of the 1st heating plate arrange | positioned inside shown in FIG. 9, and the 1st heating plate arrange | positioned outside, respectively. (A)-(c) is sectional drawing of the induction heating apparatus shown in FIG. 9, Comprising: The mode of magnetic flux is shown. 6 is a perspective view of an induction heating device according to a modification of the second embodiment. FIG. FIG. 10 is a perspective view of an induction heating device according to another modification of the second embodiment. It is a perspective view of the induction heating apparatus by Embodiment 3 which concerns on this invention. It is a disassembled perspective view of the induction heating apparatus shown in FIG. It is a perspective view of the induction heating apparatus by Embodiment 4 which concerns on this invention. It is side surface sectional drawing of the hand-drying apparatus by Embodiment 5 which concerns on this invention. It is a block diagram which shows the circuit structure of the power supply device used for the hand dryer shown in FIG. It is a graph which shows the frequency dependence of the impedance of a front side and a back side resonance circuit. It is a perspective view of the induction heating apparatus by Embodiment 6 which concerns on this invention. It is a disassembled perspective view of the induction heating apparatus shown in FIG. It is side surface sectional drawing of the warm air generator using the induction heating apparatus shown in FIG. It is side surface sectional drawing of the induction heating apparatus shown in FIG. FIG. 10 is a perspective view of an induction heating device according to a modification of the sixth embodiment. It is sectional drawing of the induction heating apparatus shown in FIG. It is a disassembled perspective view of the induction heating apparatus by Embodiment 7 which concerns on this invention. It is a partial exploded perspective view of the induction heating apparatus shown in FIG. It is sectional drawing of the induction heating apparatus shown in FIG. FIG. 10 is a cross-sectional view of an induction heating device according to a modification of the seventh embodiment. It is a disassembled perspective view of the coil by Embodiment 8 which concerns on this invention. It is sectional drawing of the coil shown in FIG.

Explanation of symbols

1: induction heating device, 10: flat coil, 11: support plate, 12: insulating case, 14: coil case (metal case), 18: cylindrical coil, 20: first heating plate, 21: slit, 22 : Outer end (coil), 23: outer periphery (first heating plate), 26: partition plate, 30: second heating plate, 32: cylindrical case, 40: spacer, 50: power supply device, 100: warm Wind generator, 101: air inlet, 102: jet outlet, 103: duct, 104: blower, 200: hand dryer, 202: housing, 203: duct, 204: blower, 206: hand insertion section, 208: air inlet , Ejection port (ejection nozzle), 210: electrical wiring, 212: ejection port (ejection nozzle), 250: power supply device, 252: switching element, 254: half-bridge circuit, 256: DC power supply, 258: half-blur Jidoraiba, 260: control unit, 300: hand dryer, 303: Duct, P: passage, F: fluid flow, B: magnetic flux.

Hereinafter, embodiments of the induction heating apparatus according to the present invention will be described with reference to the accompanying drawings. In the description of the embodiments below, terms representing directions (for example, “vertical direction” or “horizontal direction”, etc.) are used as appropriate for easy understanding. The terms are not intended to limit the present invention. Moreover, in each accompanying drawing, the same component is illustrated using the same referential mark.

Embodiment 1

FIG. 1 is a perspective view showing an induction heating device 1 according to Embodiment 1 of the present invention, and FIG. 2 is an exploded perspective view of the induction heating device 1 of FIG. The induction heating device 1 according to the first embodiment is roughly composed of a flat coil 10 formed in an arbitrary plane shape (circular shape in FIG. 2) by winding a conductive wire such as an enamel wire in a spiral shape, and on both sides thereof. A pair of first heating plates 20 disposed with a predetermined space separated by a spacer 40 and a pair of second heating plates 30 disposed with a predetermined space separated by a spacer 40 in a direction away from the coil 10. Prepare. In FIG. 2, the flat coil 10 is illustrated as being fixed to a plate-like support plate 11, but may be disposed inside an insulating case 12 made of an insulator such as resin or ceramics. However, it is also possible to construct the flat coil 10 that can stand on its own without using the support plate 11 by insulating and connecting the wound conductors (see FIG. 5).

Preferably, the pair of first heating plates 20 is made of nonmagnetic austenitic stainless steel, and the pair of second heating plates 30 is made of magnetic ferritic stainless steel. However, it is not limited to these, and the constituent material of the first heating plate 20 may be a conductor material that is not a ferromagnetic material, and is preferably made of a material having a large volume resistivity, and more preferably Austenitic stainless steel SUS304 may be used as a mass-produced and inexpensive product. The constituent material of the second heating plate 30 may be the same as the constituent material of the first heating plate 20 or may be a nonmagnetic material (nonmagnetic austenitic stainless steel), but preferably Is a ferromagnetic metal such as ferritic stainless steel or marsanto stainless steel, and SUS430, a magnetic ferritic stainless steel, is most suitable from the viewpoint of low cost.

Further, as is apparent from FIGS. 2 and 4, the first heating plate 20 of the first embodiment has a plurality of slits 21 extending radially from the center. The slits 21 do not need to intersect at the center as shown in the figure, and may be independent from each other, but their inner ends are radially inward from the inner periphery of the coil 10 and their outer ends 22 are the first ones. It is configured not to reach the outer peripheral portion 23 of the heating plate 20. That is, the outer peripheral portion 23 of the first heating plate 20 is continuous in the circumferential direction without being divided by the slit 21, and the circumferential high-frequency current generated in the first heating plate 20 is caused by the slit 21 as described later. The first heating plate 20 can flow uniformly throughout the first heating plate 20 without being blocked, and the first heating plate 20 can be heated sufficiently and uniformly.

Furthermore, the insulating case 12 including the coil 10, the pair of first heating plates 20, the pair of second heating plates 30, and the spacer 40 each have a plurality of screw holes at corresponding positions, and a plurality of screws ( These components are fixed together using an unillustrated). At this time, a predetermined interval corresponding to the thickness of the spacer 40 is provided between the insulating case 12 and the first heating plate 20 and between the first heating plate 20 and the second heating plate 30. A flow path P through which a fluid such as gas or liquid heated by these heating plates 20 and 30 flows is formed. In addition, the upper and lower ends of the insulating case 12 that houses the coil 10 are opened (not shown) to form a flow path through which the fluid flows also in the insulating case 12, so that the coil 10 in the insulating case 12 is also Similarly, it is preferable to cool with a fluid. However, in order to prevent deterioration of the coil 10 due to exposure to the fluid, the flow path does not have to be formed inside the insulating case 12. Further, both ends of the coil 10 are electrically connected to the power supply device 50, whereby a high frequency current is supplied.

Next, the operation will be described. When a high frequency current is supplied from the power supply device 50 to the coil 10, a high frequency magnetic field is generated around the coil 10. The frequency of the high-frequency current is not limited to this, but is preferably about 20 kHz to 100 kHz. FIG. 3A and FIG. 3B conceptually show the state of the magnetic flux of the high-frequency magnetic field formed when a high-frequency current is passed through the coil 10. The magnetic flux B is generated radially (in the radial direction) from the inner peripheral side to the outer peripheral side of the coil 10 on the surface side of the coil 10 as shown in FIG. 3A, and the coil 10 as shown in FIG. Is generated at the outer peripheral end of the coil 10 so as to return to the center from the outer peripheral side of the coil 10 toward the inner peripheral side on the back surface side of the coil 10. That is, the magnetic flux B is generated in a direction orthogonal to the conducting wire of the coil 10 according to the right-handed screw law. When a high frequency current is supplied to the coil 10, the direction of the magnetic flux is also reversed depending on the polarity of the high frequency current. Although FIG. 3B shows that the magnetic flux has a start point and an end point, this is for explanation, and as is clear from the Maxwell equation, the magnetic flux is continuous and there is no start point or end point. .

FIG. 4 (a) is a perspective view of the first heating plate 20 having the slits 21, and FIGS. 4 (b) and 4 (c) show the bb line and cc of FIG. 4 (a), respectively. It is sectional drawing of the induction heating apparatus 1 when it sees from a line | wire, Comprising: The mode of the magnetic flux when a high frequency current is sent through the coil 10 is shown. In these drawings, the direction of the magnetic flux is shown in one direction. Similar to FIGS. 3A and 3B, the direction of the magnetic flux is also reversed when the polarity of the high-frequency current is changed.

In the cross-sectional view of FIG. 4B, the slit 21 of the first heating plate 20 is not formed, and the magnetic flux generated in the coil 10 reaches the first heating plate 20, and the first heating plate 20 generates an induced current. An eddy current flows to inductively heat the first heating plate 20. At this time, although it depends on the constituent material and thickness of the first heating plate 20 and the flow of the eddy current of the high-frequency magnetic field, most of the magnetic flux reaching the first heating plate 20 can be transmitted therethrough. The second heating plate 30 cannot be reached (a part of the magnetic flux may pass through the first heating plate 20). On the other hand, in the cross-sectional view of FIG. 4C, a slit 21 is formed in the first heating plate 20, and the magnetic flux generated in the coil 10 reaches the second heating plate 30, and the second heating plate 30 An eddy current flows as the induced current, and the second heating plate 30 is induction-heated.

When a high-frequency current is passed through the coil 10 as described above, a total of four heating plates 20 and 30 including a pair of first heating plates 20 and a pair of second heating plates 30 generate heat by induction heating, and flow paths When a fluid such as gas or liquid is passed through P, the front and back surfaces of the respective heating plates 20 and 30 become heat transfer surfaces, so that heat is transferred to the fluid from a total of eight heat transfer surfaces, and the fluid is heated. The coil 10 also generates heat due to Joule heat (so-called copper loss) due to its own resistance, but the inside of the insulating case 12 (that is, the front surface and the back surface of the coil 10) is also configured as a flow path. In addition, heat can be efficiently transferred to the fluid, and the coil 10 can be sufficiently cooled by the fluid. Even when the coil 10 is completely covered with the insulating case 12, since the outside of the insulating case 12 is a flow path, the heat generated in the coil 10 can be transferred to the fluid through the insulating case 12.

By the way, although the 1st heating plate 20 which has the slit 21 concerning this invention consists of a nonmagnetic metal plate, an induction heating apparatus was produced using the 1st heating plate 20 which consists of a magnetic metal plate. An experiment was conducted to confirm the influence of the second heating plate 30 on the temperature increase. That is, instead of the austenitic stainless steel plate SUS304, the induction heating apparatus 1 incorporating the first heating plate 20 provided with the slit 21 in the same manner in the ferritic stainless steel plate SUS430 is operated under the same conditions. Although the plate 20 was induction heated, the second heating plate 30 was not induction heated. The reason is that even if the first heating plate 20 is provided with the slits 21, the magnetic flux generated by the coil 10 is refracted by the presence of the ferromagnetic first heating plate 20, and the first heating plate 20. This is because the magnetic flux does not pass through the slits 21 because it concentrates in the direction of. However, if the width of the slit 21 provided in the first heating plate 20 is sufficiently large, it is considered that a magnetic flux that passes through the slit 21 appears. However, increasing the width of the slit 21 is not possible for the first heating plate 20. The heat transfer area is sacrificed (reduced). Since this eliminates the effect of increasing the heat transfer area, which is the gist of the present invention, the first heating plate 20 is preferably composed of a nonmagnetic metal plate rather than a magnetic metal plate.

In addition, since the heat generating element described in Patent Document 1 is configured such that a sheet made of SUS447J1 made of ferritic stainless steel having magnetism is laminated so that the whole can be energized by spot welding, it is separated from the coil. Inductive current also flows through the sheet to generate heat, but if each sheet is not energized, only the sheet near the coil generates heat by induction heating, and the sheet away from the coil is not induction heated, so the heat transfer area is increased. I can't do it. In other words, in order to generate heat from the sheet away from the coil, each sheet must be spot-welded so that it can be energized as a whole.

On the other hand, in the induction heating device 1 of the present invention, the first heating plate 20 close to the coil 10 is configured as a non-magnetic metal plate provided with the slit 21, so that the magnetic flux transmitted through the slit 21 is from the coil 10. Even if the first and second heating plates 20 and 30 are not electrically connected, the second heating plate 30 as well as the first heating plate 20 can be connected to the second heating plate 30 that is far away. Induction heating is possible. That is, according to the induction heating apparatus 1 according to the present invention, since a plurality of heating plates 20 and 30 need only be arranged at predetermined positions without using a special manufacturing process such as spot welding, the manufacturing cost is extremely high. It can be kept low.

Next, an example of the hot air generator 100 using the induction heating device 1 according to the present invention will be described below. FIG. 5 is a cross-sectional view showing a schematic configuration of the hot air generator. 5 may be a hand dryer. A hot air generator 100 shown in FIG. 5 includes a duct 103 that fluidly communicates between the air inlet 101 and the jet outlet 102, the induction heating device 1 (FIG. 1) disposed inside the duct 103, a duct, A blower 104 that forms a fluid flow F in the inside 103 and a high-frequency power source 50 are provided. Moreover, the hot air generator 100 has a control circuit (not shown) for controlling the driving conditions of the high-frequency power supply 50.

The coil 10 of the induction heating apparatus 1 is formed by winding a 0.75 mm diameter enamel wire in a spiral shape to form a disk shape having a diameter of 140 mm, and then a nomex paper (DuPont, registered as a heat-resistant paper on the front and back surfaces). And is laminated in a rectangular case 12 having a planar size of 160 mm × 150 mm.

The first heating plate 20 is a non-magnetic stainless steel plate of SUS304 having a planar size of 160 mm × 150 mm and a thickness of 65 mm × width 1 mm (eight) extending radially from the center as shown in FIG. ) Slits are separated from each other at an angle of 45 °. The second heating plate 30 is a SUS430 magnetic stainless steel plate having a thickness of 2 mm and a planar dimension of 160 mm × 150 mm. The spacer 40 is a 150 mm × 5 mm × 3 mm SUS304 nonmagnetic stainless steel member, and has a space of 3 mm between the rectangular case 12 and the first heating plate 20 and between the first and second heating plates 30. The rectangular case 12 and the first and second heating plates 20 and 30 are fixed integrally with each other by using any suitable fixing means such as screws. Thus, the induction heating apparatus 1 according to Embodiment 1 is configured. In addition, the induction heating apparatus 1 and the duct 103 are designed so that the distance between the second heating plate 30 and the inner wall of the duct 103 is similarly 3 mm. The high-frequency power supply 50 that supplies a high-frequency current to the coil 10 will be described later, but may have any form generally used in an induction heating device, and is constituted by, for example, a resonant capacitor and two switching elements. It may be a half-bridge type inverter.

In the hot air generator 100 configured in this manner, when a high frequency current is supplied from the high frequency power supply 50 to the induction heating device 1 and the blower 104 is driven, the air sucked from the air inlet 101 of the blower 104 is converted into the induction heating device. 1 and is discharged from the outlet 102 as warm air.

In such a hot air generator 100, the electric energy input to the induction heating device 1 is converted into heat energy by the induction heating device 1, and this heat energy warms the air and also the duct 103 or the blower 104 or the like. Heat is transferred to peripheral parts by convection, conduction, and radiation. Therefore, most of the electric energy input to the induction heating device 1 is finally transferred to the air. Therefore, the temperature of the air discharged from the hot air generator 100 is measured, and the first of the induction heating device 1 is measured. It is difficult to evaluate the heat transfer performance with respect to the first and second heating plates 20 and 30. When a part of the first and second heating plates 20 and 30 or the duct 103 is excessively heated, the case 12 and the duct 103 adjacent to the first and second heating plates 20 and 30 are formed using a constituent material having heat resistance or flame retardancy. There is a need. Designing the hot air generator 100 so that some components do not become abnormally high is extremely preferable from the viewpoint of suppressing an increase in manufacturing cost. Therefore, it is preferable that the heat generated from the induction heating device 1 is more uniformly transferred to the first and second heating plates 20 and 30.

In the hot air generator 100 described above, a high frequency current having a frequency of 20 kHz is supplied to the coil 10 with a power of 400 W, and the jet outlet 102 of the blower 104 is controlled to discharge air of 1.1 m 3 / min. , raised the temperature _{T C} of the coil 10 to the intake air temperature (the surface of the conductor), raised the temperature _{T 1} of the first heating plate 20 (the average of the two), raised the temperature of the second heating plate 30 (the average of the two) T _2, and to a raised temperature T _D of the inner surface of the duct 103, respectively to obtain the results as follows. In the case of the first heating plate 20, the measurement position is a position 3 cm outside the center of the first heating plate 20, and the measurement positions of the coil 10, the second heating plate 30, and the duct 103 are also the first heating plate. This is a position corresponding to the measurement position of the plate 20.

As described above, it is confirmed that the first and second heating plates 20 and 30 have substantially the same rising temperature T ₁ and T _{2 and} are almost uniformly induction-heated by the high-frequency current flowing through the coil 10. It was.

Next, in place of the slits 21, a hot air generator using a first heating plate 20 in which circular holes 24 are arranged in a grid pattern as shown in FIG. 6 (hereinafter referred to as “perforated heating plate 25”). At 100, the same measurement as described above was performed. Specifically, as shown in FIG. 6, nonmagnetic stainless steel SUS304 having a thickness of 1 mm and circular holes 24 having a diameter of 8 mm and 6 mm arranged in a grid are prepared and incorporated in the hot air generator 100. , raised the temperature T _C, increasing the temperature T ₁ of the first heating plate is perforated heating plate (average of _two), the second heating plate of the coil 10 (surface of the wire) to the intake air temperature of the fluid flow F (2 the elevated temperature T _D of elevated temperature T _2, and the duct surface of the sheets average) were measured. At this time, the opening ratio of the circular holes 24 to the perforated heating plate (ratio of the area occupied by the entire circular holes 24 to the surface area of the perforated heating plate 25) was about 58% and about 40%, respectively. In contrast, when the eight slits 21 having a length of 65 mm and a width of 1 mm extending radially from the center are provided in the first heating plate 20 shown in FIG. is there.

According to the results in Table 2, although the first heating plate 20 that is the perforated heating plate 25 has been confirmed to have a temperature increase of 100 K or more, the second heating plate 30 has a very high temperature regardless of the aperture ratio. Not. That is, the magnetic flux B from the coil 10 does not pass through the first heating plate 20 even if many circular holes 24 are provided, and does not reach the second heating plate 30. On the other hand, according to the results shown in Table 1, the second heating plate 30 is the second heating plate 30 even though the aperture ratio due to the slit 21 when the slits 21 are provided in the first heating plate 20 is relatively small at about 2.2%. The slit 21 extending in the same direction as the direction of the magnetic flux has an extremely large influence on the effect of transmitting the magnetic flux B as compared with the circular hole 24 since It can be seen that the effect of increasing the heat transfer area according to the invention acts remarkably.

Similarly to the above, a nonmagnetic stainless steel SUS304 having a thickness of 1 mm and circular holes 24 having a diameter of 8 mm, 6 mm, and 3 mm arranged in a lattice shape is further added to the perforated heating plate 25 and the length extending radially from the center. A device provided with eight slits 21 of 65 mm × width 1 mm was manufactured, and the same measurement as described above was performed in the hot air generator 100 using this as the first heating plate 20. In other words, the slit 21 according to the present invention is used, and the aperture ratio of the circular holes 24 is about 58%, about 40%, and about 33% (the perforated heating plate 25 having a circular hole with a hole diameter of 3 mm) 3. For the type of perforated heating plate 25, the coil rising temperature T _C , the first heating plate rising temperature T ₁ , the second heating plate rising temperature T ₂ , and the duct surface rising temperature with respect to the intake air temperature of the fluid flow F It was measured T _D. The aperture ratio does not include the aperture ratio due to the slit 21, and the first heating plate 20 that does not have the circular holes 24 and has only the slits 21 has the aperture ratio of 0%. The same measurement was performed (Table 3). And the graph of FIG. 7 was obtained by plotting each rising temperature in each aperture ratio.

Comparing Table 2 and Table 3, even when the circular hole 24 is provided in the first heating plate, the first heating plate 20 when the first heating plate 20 has the slit 21 (Table 3). elevated temperatures T ₁ of, if no slit 21 (Table 2) lower than the elevated temperature T ₂ of the second heating plate 30 is clear that higher. In this manner, similarly, by providing the slit 21 in the perforated heating plate 25, it is possible to increase the heat transfer area by giving high magnetic flux energy to the second heating plate 30 for induction heating.

Further, as understood from the graph of FIG. 7, as the aperture ratio increases, the rising temperature T1 of the _first heating plate 20 becomes lower and the rising temperature T2 of the _second heating plate 30 becomes higher. Therefore, by controlling the aperture ratio of the circular holes 24 provided in the first heating plate 20, the rising temperatures T ₁ and T ₂ of the first and second heating plates 20 and 30 can be controlled. Alternatively, the rising temperatures T ₁ and T ₂ of the first and second heating plates 20 and 30 can be controlled by the number and width of the slits 21 provided in the first heating plate 20. Since the rising temperatures T ₁ and T ₂ of the first and second heating plates 20 and 30 can be controlled by controlling the aperture ratio of the circular holes 24 provided in the first heating plate 20, However, there is an advantage that the degree of freedom of design increases.

Next, instead of the non-magnetic stainless steel plate, four slits 21 having a length of 65 mm and a width of 1 mm extending radially from the center are spaced apart from each other at an angle of 90 ° on an aluminum plate (160 mm × 150 mm × 1 mm). Further, circular holes 24 having diameters of 8 mm, 6 mm, and 3 mm were arranged in a lattice shape (opening ratios by the circular holes 24 were about 58%, about 40%, and about 33%, respectively. .) And in the warm air generator 100 which used these aluminum perforated heating plates 25 as the 1st heating plate 20, the same measurement as the above was performed. 8, each aperture ratio, elevated temperature _{T 2} of the temperature increase _{T 1,} the second heating plate 30 of the rise of the coil with respect to the intake air temperature of the fluid flow F temperature _{T C,} the first heating plate 20, and the duct 103 is a graph plotting the respective measurement results of the temperature increase T _D of the surface of the.

As is apparent from FIG. 8, the rising temperatures T ₁ and T ₂ of the first and second heating plates 20 and 30 are approximately the same, and both the heating plates 20 and 30 are equally induction-heated, The rising temperature T _C of the coil 10 is higher than the rising temperatures T ₁ and T _{2 of} the first and second heating plates 20 and 30. In general, when the coil 10 reaches a very high temperature, peripheral parts such as the case 12 that accommodates the coil 10 must be formed using a material having a higher heat-resistant temperature. it is preferable to suppress the temperature increase _{T C} of the coil 10. Therefore, as described above, the upper end and the lower end of the case 12 including the coil 10 are opened to form a flow path through which the fluid flows also inside the case 12, and the coil 10 is cooled by the fluid, and from the aluminum plate Rather, it is more preferable to configure the first heating plate 20 using a nonmagnetic stainless steel plate.

In addition, when the 1st heating plate 20 is comprised using an aluminum plate, the reason for the coil 10 becoming higher temperature is that the resistance of the aluminum plate is smaller than the resistance of the SUS304 stainless steel plate, so that the coil 10 of the induction heating apparatus 1 is used. This is because the resistance component induced in the first heating plate 20 when a high-frequency current is passed through is small, and the ratio of the power consumed by the coil 10 is large. As estimated from the impedance measurement of the induction heating device 1, when the first heating plate 20 is a SUS304 stainless steel plate, about 6 to 7% of the input power is consumed by the coil 10, but in the case of an aluminum plate, About 20% of power is consumed by the coil 10. In order to suppress the power consumption of the coil 10 to a small value, the resistance of the first heating plate 20 may be increased. For this purpose, a material having a large volume resistivity may be used or the plate thickness may be reduced. The volume resistivity of the SUS304 stainless steel plate at room temperature is 71 × 10 ⁻⁸ Ωm, and the volume resistivity of the aluminum plate is 2.75 × 10 ⁻⁸ Ωm. Non-magnetic metal and high volume resistivity materials include nichrome (110 × 10 ⁻⁸ Ωm), chromel (70 to 100 × 10 ⁻⁸ Ωm), constantan (47 to 51 × 10 ⁻⁸ Ωm), Although these may be used, austenitic stainless steel is optimal as a material that can be obtained at low cost. Austenitic stainless steel has a volume resistivity of 71 to 94 × 10 ⁻⁸ Ωm at room temperature. On the other hand, if the plate thickness is reduced, the resistance of the aluminum plate can be increased even with a material having a small volume resistivity such as aluminum. Even if it is an aluminum plate, if the plate thickness is 0.1 mm or less, the resistance of the aluminum plate is sufficiently large and the power consumed by the coil 10 can be sufficiently reduced. However, if the plate thickness is thin, it is easily deformed by heat generated by induction heating. Become. Therefore, a design that allows for deformation of the aluminum plate is required. However, the use of aluminum, which is cheaper than stainless steel, is advantageous in terms of cost reduction. Even if the plate thickness is set to 0.1 mm or more and the power consumed by the coil 10 is slightly increased, the periphery of the coil 10 is a flow path. This is possible because it is cooled.

Furthermore, the same measurement as described above was performed when the width of the slit 21 of the first heating plate 20 was set to 5 mm instead of 1 mm. That is, the first heating plate 20 is a SUS304 nonmagnetic stainless steel plate having a thickness of 160 mm × 150 mm and a SUS304 thickness of 65 mm × 1 mm wide extending radially from the center as shown in FIG. A plurality of (eight) slits are formed so as to be separated from each other at an angle of 45 °, and the circular hole 24 is not provided. Table 4 shows the measurement results.

Comparing Table 1 when the slit width is 1 mm and Table 4 when the slit width is 5 mm, the rising temperature T1 of the _first heating plate 20 when the slit width is 5 mm is smaller, The rising temperature T2 of the _second heating plate 30 is larger. This is because the amount of magnetic flux passing through the slit 21 is increased by increasing the slit width, the magnetic flux for induction heating of the first heating plate 20 is decreased, and the magnetic flux for induction heating of the second heating plate 30 is increased. It is. However, although the slit width is five times, the temperature rise is not so great.

In the present embodiment, the specific geometrical values have been described, but the dimensions of the heating plates 20 and 30, the coil 10, and the spacer 40 are not limited to this. If a similar structure is realized, a space serving as the flow path P may be formed without using the spacer 40 and without using the spacer 40 by bending the ends of the heating plates 20 and 30. In addition, although two each of the first heating plate 20 and the second heating plate 30 are provided on both surfaces of the coil 10, the first heating plate 20 and the second heating plate 30 are provided on one surface of the coil 10. May be.

Embodiment 2

Embodiment 2 of the induction heating apparatus according to the present invention will be described with reference to FIGS. The induction heating device 2 according to the second embodiment has the same configuration as that of the first embodiment except that a plurality of first heating plates 20 are provided on both sides of the coil 10. Description is omitted.

FIG. 9 is a perspective view showing the induction heating device 2 according to the second embodiment of the present invention. The induction heating device 2 of the second embodiment includes a first heating plate 20a made of nonmagnetic austenitic stainless steel disposed on both sides of a case 12 that houses the coil 10 (FIG. 10 (a)), and on the outside thereof. It has another 1st heating plate 20b which consists of the material of the equivalent nonmagnetic material arrange | positioned (FIG.10 (b)), and also has the 2nd heating plate 30 arrange | positioned on the outer side. That is, the first heating plate has a plurality of first heating plates 20a and 20b disposed between the coil 10 and the second heating plate 30, and a flow path P is formed between each of them. Yes.

As shown in FIG. 10A, the first heating plate 20a closer to the coil 10 is formed so that twelve slits of 65 mm in length and 1 mm in width extending radially from the center are separated from each other at an angle of 30 °. The first heating plate 20b disposed further away from the coil 10 has six slits of 65 mm in length and 1 mm in width extending radially from the center as shown in FIG. It is formed so as to be separated by an angle of °. The slit 21b of the first heating plate 20b arranged on the outer side is formed so as to overlap (superimpose) the slit 21a of the first heating plate 20a arranged on the inner side when viewed from the direction perpendicular to the first heating plate 20a. ing. 11 (a) to 11 (c) are cross-sectional views of the induction heating device 2 as viewed from the aa, bb, and cc lines in FIGS. 10 (a) and 10 (b). It is. As shown in FIG. 11A, the first heating plate 20 a disposed on the inner side cannot transmit the magnetic flux B in the absence of a slit and is induction-heated by the magnetic flux from the coil 10. As shown in FIG. 11B, the first heating plate 20b arranged outside cannot transmit the magnetic flux B in the absence of the slit 21b, and the slit 21a of the first heating plate 20a arranged inside. Inductive heating is performed by the magnetic flux B transmitted through the. Further, the second heating plate 30 is induction-heated by the magnetic flux transmitted through the slits 21a, 21b of both the first heating plates 20a, 20b.

In the induction heating apparatus 2 configured in this way, by providing the slits 21a and 21b in the first heating plates 20a and 20b, all the heating plates 20a, 20b and 30 can be induction-heated, and the heat transfer area Can be further increased. Further, by making the width of the slit 21a of the first heating plate 20a arranged on the inner side wider than the width of the slit 21b provided on the first heating plate 20b arranged on the outer side, the magnetic flux is surely applied to the second heating plate 30. You may make it reach. The same number of slits 21 are provided on the first heating plate 20a arranged on the inner side and the first heating plate 20b arranged on the outer side so as to overlap each other, and the width of the former slit 21a is formed wider than that of the latter slit 21b. A part of the magnetic flux B transmitted through the slit 21a of the first heating plate 20a induces and heats the first heating plate 20b, and the remaining magnetic flux B passes through the first heating plate 20b and passes through the second heating plate 30. May be induction heated.
In the present embodiment, the induction heating device 2 having the two first heating plates 20a and 20b arranged inside and outside the coil 10 and the second heating plate 30 has been described. Since it reaches 10 to several centimeters, more first heating plates 20 may be provided.

FIG. 12 is a perspective view showing an induction heating device 2 having four first heating plates 20 on both sides of the coil 10 and a second heating plate 30 on the outside thereof. In this way, a larger number of first heating plates 20 can be arranged to realize a larger heat transfer area. When the number of the first heating plates 20 increases, the first heating plate 20 disposed on the outer side is farther away from the coil 10, so that the magnetic flux from the coil 10 becomes weaker and the induction heating becomes difficult. . Therefore, as shown in FIG. 13, a plurality of first heating plates 20 may be induction-heated using a plurality of coils 10. At this time, it is preferable to adjust the width of the slit 21 so that each of the first heating plates 20 is heated evenly, but the plurality of first heating plates so that the slit widths are different (different shapes). Since the formation of the plate 20 causes high costs, it is preferable to use the induction heating device 2 by using the first heating plate 20 having the same shape as much as possible in order to manufacture the plate 20 at a low cost. When the first heating plate 20 having the same shape is used, the rising temperature (T ₁ ) varies depending on the distance from the coil 10 to each of the first heating plates 20, but the heated fluid generates the above-described hot air. The fluid that is agitated inside the main body device (not shown) such as the device 100 and ejected from the main body device has a uniform temperature, and there is often no problem in actual use. In addition, in the induction heating apparatus 2 shown in FIGS. 12 and 13, the second heating plate 30 is arranged on the outermost side. However, in order to reduce the number of parts and reduce the cost, the first heating plate 20 is used. It may be replaced.

Embodiment 3

Embodiment 3 of the induction heating apparatus according to the present invention will be described with reference to FIGS. The induction heating device 3 of the third embodiment is the same as that of the second embodiment except that the first heating plate 20a and the second heating plate 30 disposed inside are provided with undulations (unevenness) to increase the heat transfer area. Since the configuration is the same as that in FIG.

As described above, the induction heating device 3 shown in FIGS. 14 and 15 has a case 12 that houses the coil 10 and a nonmagnetic metal plate (for example, a metal plate made of SUS304) bent into a corrugated shape (provided with irregularities). A first heating plate 20a having radial slits 21a, a first heating plate 20b in which slits 21b are radially provided on a flat nonmagnetic metal plate on the outside thereof, and a magnetic metal plate (for example, from SUS430) on the outside thereof. And a second heating plate 30 provided with continuous undulations by bending the metal plate) into a corrugated shape.

In the induction heating apparatus 3 configured as described above, when a high-frequency current is supplied to the coil 10, the first heating plates 20a and 20b and the second heating plate 30 are induction-heated as in the first and second embodiments. The However, in the present embodiment, the first heating plate 20a and the second heating plate 30 arranged inside are formed in a continuous corrugated shape, and compared with a flat metal plate, the contact area with the fluid (transmission) The heat transfer effect can be improved because the heat area can be increased.

The first heating plate 20a having a corrugated shape disposed inside and the second heating plate 30 having the corrugated shape (hereinafter collectively referred to as “corrugated metal plate”) fix the coil 10. Between the flat support plate 11 (or the case 12 housing the coil 10) and the flat first heating plate 20b arranged outside, between the peaks and the mountains (or between the valleys). Form. Therefore, the induction heating device 3 according to Embodiment 3 does not require a spacer as a separate member in order to form the flow path. When the flow path is formed by fixing the corrugated metal plate and the flat metal plate (planar first heating plate 20 arranged outside) using the spacer 40 as shown in the first and second embodiments, induction is performed. When the temperature of the corrugated metal plate rises due to heating, the flat metal plate may thermally expand and warp larger than the corrugated metal plate in its parallel plane, making it difficult to maintain the flow path in a stable shape. Accordingly, the flat support plate 11, the first heating plates 20a and 20b, and the second heating plate 30 that fix the coil 10 are not fixed via the spacer 40, as shown in FIGS. It is desirable to construct so that it is simply laminated. More preferably, the first heating plate 20b having a flat plate is formed using an insulator that does not easily thermally expand so that the first heating plate 20a and the second heating plate 30 that are corrugated metal plates do not warp. May be. However, the flat first heating plate 20b is preferably formed using a nonmagnetic metal material rather than an insulator because the heat transfer area can be increased.

Embodiment 4

Embodiment 4 of the induction heating apparatus according to the present invention will be described with reference to FIG. FIG. 16 is a perspective view showing an induction heating device 4 according to Embodiment 4 of the present invention. The induction heating device 4 according to the fourth embodiment generally includes a cylindrical case 32 made of an insulator such as ceramics, a cylindrical coil 18 wound around the outside thereof, and a predetermined interval inside the cylindrical case 32. And a plurality of heating plates 20 made of a non-magnetic metal plate (for example, a metal plate made of SUS304). When a high frequency current is supplied to the cylindrical coil 18 from a high frequency power source (not shown), a high frequency magnetic field is generated in the longitudinal direction of the cylindrical case 32 (up and down direction in FIG. 16). Each of the plurality of heating plates 20 is provided with a plurality of slits 21 extending in the same direction as the direction of the magnetic flux B of the high frequency magnetic field formed by the cylindrical coil 18 (the longitudinal direction of the cylindrical case 32). At this time, a part of the magnetic flux B of the high frequency magnetic field from the cylindrical coil 18 induction-heats the heating plate 20 closest to the cylindrical coil 18, but a part thereof passes through the slit 21 provided on the heating plate 20. Then, it reaches the heating plate 20 on the inner side, and this is induction-heated. The heating plate 20 is most preferably austenitic stainless steel SUS304 similar to the first heating plate 20 described in the first embodiment.

In the present embodiment, the heating plate 20 is a flat plate. However, as shown in the third embodiment, the heating plate 20 bent in a waveform may be provided with a slit 21. The cylindrical case 32 is not limited to a cylindrical cross section, and may be a hollow body having a rectangular cross section.

Embodiment 5

Induction heating apparatuses 1 to 3 according to Embodiments 1 to 3 are configured by a combination of a flat coil 10 and a plurality of flat heating plates 20 and 30, so that fluid heating is thin and has a large heat transfer area. Induction heating apparatus can be obtained. Such an induction heating apparatus can be used as a heat source for various apparatuses. As an example, a hand drying apparatus 200 incorporating the induction heating apparatus 1 according to Embodiment 1 will be described below. A typical hand dryer using a sheath heater is described in, for example, Japanese Patent Application Laid-Open No. 10-75915, and the disclosure thereof is integrated here as a single unit for reference.

FIG. 17 is a side cross-sectional view showing the hand dryer 200 according to the fifth embodiment. The hand dryer 200 generally includes a housing 202, a blower 204 that is a high-pressure air generator that generates high-pressure air, and a power supply device 250. The housing 202 includes a manual insertion portion 206, an intake port 208 for taking in ambient air, jet ports (spout nozzles) 212a and 212b for jetting air heated by the induction heating device 1, and an intake port 208. The jet outlets 210a and 210b are in fluid communication with each other and have a front side duct 203a provided on the front side of the hand insertion portion 206 and a back side duct 203b provided on the back side. A front side induction heating device 1a and a back side induction heating device 1b similar to the induction heating device 1 of the first embodiment are disposed inside the front side duct 203a and the back side duct 203b, respectively. The induction heating devices 1a and 1b are electrically connected to the power supply device 250 by electric wirings 210a and 210b, and a high frequency current is supplied from the power supply device 250 to the induction heating devices 1a and 1b. The power supply device 250 has a control circuit (not shown) for controlling the blower 204 and the induction heating devices 1a and 1b.

In the hand dryer 200 configured as described above, when the blower 204 is operated, air is sucked from the air inlet 208, and the front side induction heating device 1a and the back side induction heating device 1b heat the air, and then the heated high pressure and high speed The air jet F is ejected from the front side nozzle 212a and the back side nozzle 212b. At this time, when the user of the hand drying apparatus 200 inserts a wet hand into the hand insertion portion 206 and pulls it out, the air jet (warm air) F ejected from the front side nozzle 212a and the back side nozzle 212b is placed in the hand. The attached water droplets can be blown away to quickly dry the hands.

It is preferable that the hand insertion unit 206 of such a hand drying apparatus 200 has a width that allows both hands to be inserted in the vertical direction (depth direction) of the paper surface of FIG. 17 and has a depth that allows insertion to the wrist in the vertical direction. Moreover, it is preferable that the manual insertion part 206 has a space | interval wide enough not to give a user a feeling of pressure in the left-right direction on the paper surface of FIG. However, in order to make the installation space (occupied area) of the hand dryer 200 as small as possible, it is desirable that the distance between the left and right directions of the hand insertion portion 206 is small. Therefore, in order to increase the distance between the hand insertion portions 206 of the hand dryer 200 in the left-right direction of FIG. 17 and to reduce the depth of the entire hand dryer 200, the front side duct 203a and the rear side duct 203b are provided inside. It is necessary to design the arranged induction heating devices 1a and 1b as thin as possible, and the induction heating device of the present invention is extremely suitable.

For example, in the induction heating apparatus 1 according to the first embodiment, the thickness of the coil 10 is 2 mm, the space (flow path) between the coil 10 and the first heating plate 20 is 3 mm, and the thickness of the first heating plate 20 is Since 1 mm, the space (flow path) between the first and second heating plates 30 is 3 mm, and the thickness of the second heating plate is 2 mm, the thickness of the induction heating device 1 as a whole is 20 mm. Furthermore, when a 3 mm space (flow path) is provided between the induction heating device 1 and the duct 203, the depth of the duct 203 is 26 mm. If the space (flow path) through which the airflow passes is 2 mm, the depth of the duct 203 is 20 mm. Although the induction heating device 1 of the present invention is thin, since the heat transfer area is large, air can be sufficiently heated without excessively increasing the temperature of the induction heating device 1.

In addition, the front side induction heating device 1a and the back side induction heating device 1b may be individually controlled so that the temperatures of the air ejected from the front side nozzle 212a and the back side nozzle 212b are different from each other. The user usually inserts the hand into the hand insertion portion 206 so that the palm faces the front side nozzle 212a, so the warm air blown from the front side nozzle 212a hits the palm and is blown from the back side nozzle 212b. Hot air hits the back of the hand. In general, when a hand is washed, more water droplets adhere to the palm than the back of the hand. Moreover, when the temperature of the air ejected from the front side nozzle 212a and the back side nozzle 212b is the same, the back of the hand feels hotter than the palm of the hand, which may cause discomfort to the user. Therefore, in order to dry the hand in a short time, it is preferable that the temperature of the air ejected from the front side nozzle 212a is higher than the temperature of the air ejected from the back side nozzle 212b. In order to realize this, two independent power supply devices 250 that supply high-frequency current to the front side induction heating device 1a so that the power supplied to the front side induction heating device 1b is larger than the power supplied to the back side induction heating device 1b. May be provided and controlled individually. At this time, the hand dryer 200 may be configured so that the user can adjust the temperature of the air ejected from the front nozzle 212a and the back nozzle 212b.

However, providing the two power supply devices 250 for the front side induction heating device 1a and the back side induction heating device 1b and controlling them individually increases the manufacturing cost of the hand drying device 200. As an alternative, when the high frequency current is supplied to the front side induction heating device 1a and the back side induction heating device 1b connected in parallel by the single power supply device 250, the number of turns of the former coil 10 is set to the latter. When the number is increased or when both are connected in series, the temperature of the air ejected from the front side nozzle 212a is ejected from the rear side nozzle 212b by reducing the number of turns of the former coil 10 than the latter. The hand dryer 200 may be configured to be higher than the temperature of the air.

Further alternatively, a single power supply device 250 can be configured such that two induction heating devices 1a, 1b configured similarly, such as the number of turns of the coil 10, consume different power. FIG. 18 is a block diagram showing a circuit configuration of a power supply apparatus 250 that supplies different electric power to the front side induction heating apparatus 1a and the back side induction heating apparatus 1b. The power supply apparatus 250 includes a half bridge circuit 254 in which switching elements 252a and 252b such as IGBTs are connected in series. A DC voltage is supplied from the DC power supply 256 to the half bridge circuit 254, and is switched by the switching elements 252 a and 252 b of the half bridge circuit 254, and a predetermined rectangular wave voltage is output to the output stage of the half bridge circuit 254. The switching elements 252 a and 252 b of the half bridge circuit are driven by the half bridge driver 258, and the half bridge driver 258 is controlled by the control unit 260. A capacitor 262 is connected between the DC power supply 256 and the half bridge circuit 254, and the current is smoothed as necessary and supplied to the half bridge circuit 254. A front-side induction heating device 1a having a resonance capacitor C1 connected in series and a back-side induction heating device 1b having a resonance capacitor C2 connected in series are connected in parallel to the output terminal of the half bridge circuit 254. .

Next, the operation will be described. The inductances of the front side induction heating device 1a and the back side induction heating device 1b may be different, but will be described below assuming that they are the same. The power supply device 250 shown in FIG. 18 includes two resonance circuits, that is, a front-side resonance circuit RC1 including a front-side induction heating device 1a and a resonance capacitor C1 connected in series, and a back-side induction heating device 1b and a resonance capacitor connected in series. And a back side resonance circuit RC2 by C2. The capacitances of the resonance capacitors C1 and C2 are different from each other, and FIG. 19 is a graph showing the frequency dependence of the impedances of the front-side resonance circuit RC1 and the back-side resonance circuit RC2. The minimum value of each impedance is the resonance frequency of each resonance circuit. When a rectangular wave voltage having a frequency f1 higher than the resonance frequency of the front-side resonance circuit RC1 is output from the half-bridge circuit and supplied to the front-side induction heating device 1a and the back-side induction heating device 1b, the impedance of the front-side resonance circuit RC1 Is smaller than the impedance of the back-side resonance circuit RC2, the front-side induction heating device 1a is supplied with a larger current than the back-side induction heating device 1b, and consumes a larger amount of power (has a larger amount of heat generation). When the frequency of the rectangular wave voltage output from the half-bridge circuit 254 is increased from f1 to f2, the impedance of the front-side resonance circuit RC1 is similarly smaller than the impedance of the back-side resonance circuit RC2, but the difference between the two impedances Is smaller than when the frequency of the rectangular wave voltage is f1. That is, by adjusting the frequency of the rectangular wave voltage output from the half-bridge circuit 254 and controlling the duty ratio thereof, the power consumption of one induction heating device is kept constant while the other induction heating device is kept constant. Power consumption can be controlled.

Embodiment 6

In the above-described embodiment, the induction heating apparatus provided with a plurality of heating plates on both sides of the coil has been described. However, in this embodiment, the induction has a simpler configuration in which a single heating body is disposed on each side of the coil. The heating device will be described below.

20 is a perspective view showing the induction heating device 6 according to Embodiment 6 of the present invention, and FIG. 21 is an exploded perspective view of the induction heating device 6 shown in FIG. The induction heating device 6 according to the sixth embodiment includes the same coil 10 as that of the first embodiment and the heating plate 20 that is arranged at a predetermined interval with a spacer 40 interposed between the coil 10 and the heating plate. A flow path P is formed between the The heating plate 20 is preferably a magnetic metal such as SUS430 of ferritic stainless steel, but may be a nonmagnetic metal such as SUS304 of austenitic stainless steel. As in the first embodiment, when a high frequency current is supplied to the coil 10, the heating plate 20 is induction heated. Heat is transferred from the heating plate 20 to the air (air is heated) by flowing a fluid such as air through the flow path P between the coil 10 and the heating plate 20. Thus, since the front surface and the back surface of each heating plate 20 transfer heat to the air as a heat transfer surface, the heat transfer area is doubled compared to the case where the flow path P is not provided between the coil 10 and the heating plate 20. Can be increased. In order to improve the heat transfer efficiency, it is preferable that the heat generated in the coil 10 is also directly transferred to the air and the coil 10 is similarly exposed to the air flow (cooled by air). At this time, when the coil 10 is exposed to an air flow, the insulating coating of the coil 10 is easily damaged by dust in the air. Therefore, the coil 10 is preferably covered with an insulator such as resin, glass, or ceramic.

FIG. 22 is a side cross-sectional view showing a hand dryer 300 incorporating the induction heating device 6 of FIG. A hand dryer 300 shown in FIG. 22 is substantially the same as the hand dryer 200 shown in FIG. 17 of the fifth embodiment. FIG. 23 is an enlarged cross-sectional view showing a portion surrounded by a thick broken line A in FIG. 22, which is substantially the same as the induction heating device 6 in FIG. 20. In the induction heating device 6 shown in FIG. 23, a predetermined interval is also provided between the heating plate 20 and the duct 303, and a flow path P is formed between the two, and a total of four flow paths P are formed. ing. That is, the induction heating device 6 according to Embodiment 6 induction-heats the two heating plates 20 with one coil 10, and both the front and back surfaces of the two heating plates 20 serve as heat transfer surfaces (a total of four surfaces). Configured to work. Therefore, since a larger number of heat transfer surfaces can be realized by using a limited number of coils 10 and heating plates 20, it is possible to manufacture a small induction heating device 6 with higher heat transfer efficiency and lower cost. .

FIG. 24 is a perspective view of a plurality of induction heating devices 6 shown in FIG. 20 arranged in parallel via spacers 41, and FIG. 25 is parallel to a horizontal plane (a plane perpendicular to the flow path P). It is sectional drawing when cut | disconnecting in a smooth surface. According to the induction heating device (FIGS. 24 and 25) configured as described above, the same operation and effect as the induction heating device 6 shown in FIG. 20 can be realized, and since it has a large number of heat transfer surfaces, it is more efficient. Heat can be transferred to the air and warm air can be obtained.

The plurality of induction heating devices 6 shown in FIG. 20 are arranged so as to be separated from each other by using the spacers 41. However, the present invention is not limited to this, and the outside is provided with grooves provided at predetermined intervals. Each of the plurality of induction heating devices 6 may be disposed on a frame (not shown) so as to be fitted in the groove portion and separated from each other.

Embodiment 7

FIG. 26 is an exploded perspective view showing the induction heating device 7 according to the seventh embodiment of the present invention, and FIG. 27 is a partial exploded perspective view of the induction heating device 7 of FIG. Although the coil 10 of the induction heating device 7 is substantially the same as that of the sixth embodiment, the heating plate 20 of the induction heating device 7 is not flat and is formed by being bent into a waveform. Between the coil 10 and the heating plate 20, a flow path P is formed between the mountains (between adjacent peaks) without providing a spacer. FIG. 28 is a cross-sectional view when the induction heating device 7 shown in FIGS. 26 and 27 is cut along a plane parallel to a horizontal plane (a plane orthogonal to the flow path P). In the partial region L in the left half of FIG. 28, the ridges of the respective heating plates 20 are arranged so as to coincide (facing) with each other. In the partial region R in the right half of FIG. Although the 20 peaks and valleys are arranged so as to coincide (face each other), the plurality of heating plates 20 may be arranged at arbitrary positions as long as the direction of the flow path P is constant.

However, the winding direction of each of the plurality of coils 10 is preferably the same. This is because leakage magnetic flux generated due to a space serving as the flow path P between the coil 10 and the heating plate 20 weakens each other's magnetic flux. For example, if the winding direction of one of the plurality of coils 10 is opposite to the other, the temperature rise of the coil 10 itself is greater when the same power is input than when the same direction is used. That is, Joule heat from the coil 10 increased. Also in the present embodiment, air is passed through the flow path P between the coil 10 and the heating plate 20, and the heat from the coil 10 is also transferred to the air, but the surface of the coil 10 is covered with an insulator. Therefore, in order to more efficiently transfer heat to the air, it is preferable to increase the ratio of induction heating from the heating plate 20 to Joule heat from the coil 10 with respect to input power.

Thus, according to the seventh embodiment, by forming the heating plate 20 by bending the flat plate into a corrugated shape, the heat transfer area can be increased as compared with the flat plate, and the heat transfer efficiency to the air can be improved. .

FIG. 29 is a similar cross-sectional view showing a modification of the induction heating device 7 shown in FIG. In the induction heating device 7 of FIG. 28, a single heating plate 20 is disposed between adjacent coils 10, whereas in the induction heating device 7 shown in FIG. Two heating plates 20 and a partition plate 26 are provided. The partition plate 26 is sandwiched between two corrugated heating plates 20 and maintains a distance therebetween, and is preferably made of a metal plate, but is made of an insulating material such as glass, ceramics, or resin. Also good. Even if the partition plate 26 is a metal plate, the heat generated by induction heating is small, but rather, heat is easily transferred from the corrugated heating plate 20 that has been induction heated. At this time, since the partition plate 26 constitutes a part of the flow path P, it functions as a heat transfer surface to the air. Therefore, the induction heating apparatus shown in FIG. 29 can be induction-heated (increase the heat transfer surface more) with a smaller number of coils 20 than the apparatus shown in FIG. In addition, an induction heating device with high transmission efficiency can be realized.

Embodiment 8

In the above embodiment, the coil 10 is described as being housed in the insulating case 12 made of an insulating material such as resin or ceramics. However, the coil 10 according to the present embodiment is housed in the coil case 14 made of a metal material. Since it has the same configuration as that of the above-described embodiment except for the point, it can be replaced with an arbitrary coil used in the induction heating device of the above-described embodiment. That is, the coil of the eighth embodiment can be applied not only to the sixth and seventh embodiments but also to all the coils according to the first to seventh embodiments.

The coil 10 according to the eighth embodiment will be described below with reference to FIGS. 30 is an exploded perspective view showing the coil 10 according to the eighth embodiment, and FIG. 31 is a cross-sectional view of the coil shown in FIG. 30 taken along a plane parallel to the horizontal plane. The coil 10 according to the eighth embodiment is formed by winding a conductive wire such as an enamel wire in a spiral shape, and is sandwiched between coil cases 14a and 14b made of a pair of metal materials (FIG. 30) and fixed integrally (FIG. 31). The coil cases 14a and 14b are preferably made of a non-magnetic metal such as aluminum and have a plurality of slits 21 extending radially from the vicinity of the center of the coil 10 as shown in FIG. The magnetic flux generated in the coil 10 passes through the coil cases 14a and 14b, and the heating plate disposed away from the coil 10 can be induction-heated. The coil cases 14a and 14b are similarly induction-heated by the magnetic flux from the coil 10, but the heat generated in the coil cases 14a and 14b is suppressed by increasing the number of slits 21 or increasing the width thereof. be able to. In the above embodiment, since the coil 10 is configured to face the flow path P, the coil cases 14a and 14b according to this embodiment are effectively used as a heat transfer surface for heating the fluid. You can also Although not shown in detail, an insulating sheet (not shown) made of an insulating material such as resin may be disposed between the coil 10 and the coil cases 14a and 14b. Moreover, even if the slit 21 is closed with an insulator, the slit 21 may be the same as the existence of a slit for the magnetic flux.

As described above, according to the eighth embodiment, by disposing the coil 10 in the metal coil cases 14a and 14b, the substantial entire surface of the coil 10 is protected from dust contained in the fluid. The coil 10 can be prevented from being deteriorated due to wear due to dust, and the coil 10 having a longer life and higher reliability can be realized.

Claims (16)

1. Coils,
   At least one first heating plate made of a non-magnetic conductor and forming a flow path with the coil;
   A second heating plate made of a conductor and forming a flow path with the first heating plate;
   A high frequency power source for supplying a high frequency current to the coil;
   The induction heating apparatus according to claim 1, wherein the first heating plate has a slit extending in substantially the same direction as a direction of magnetic flux generated in the coil.
2. The induction heating apparatus according to claim 1, wherein the first heating plate is made of austenitic stainless steel.
3. 3. The coil according to claim 1, wherein the coil is a flat coil formed by winding a conductive member in a spiral shape, and a first heating plate is disposed so as to sandwich the flat coil. The induction heating apparatus described.
4. The induction heating apparatus according to claim 3, wherein the outer peripheral portion of the first heating plate is continuous in the circumferential direction without being divided into slits.
5. The first heating plate is a plurality of first heating plates disposed between the flat coil and the second heating plate, and forms a flow path between them.
   More slits of the first heating plate that are closer to the flat coil than the slits of the first heating plate that are further away from the flat coil, and are substantially superimposed on the slits.
   The induction heating apparatus according to claim 4, wherein the second heating plate is heated by a magnetic flux transmitted through the slit provided in each of the plurality of first heating plates.
6. The first heating plate is composed of a plurality of heating plates disposed between the flat coil and the second heating plate and forming a flow path between them.
   The slit of the first heating plate that is closer to the flat coil has a width equal to or wider than the slit of the first heating plate that is further away from the flat coil. Is superimposed on the
   The induction heating apparatus according to claim 4, wherein the second heating plate is heated by a magnetic flux transmitted through the slit provided in each of the plurality of first heating plates.
7. 3. The coil according to claim 1, wherein the coil is a cylindrical coil formed by winding a conductive member in a spiral shape, and a first heating plate is disposed inside the cylindrical coil. Induction heating device.
8. The induction heating apparatus according to any one of claims 1 to 7, wherein at least a part of the first heating plate is formed in a wave shape.
9. The induction heating apparatus according to any one of claims 1 to 8, wherein the coil is accommodated in an insulating case made of an insulating material.
10. A flat coil formed by winding a conductive member in a spiral;
    A pair of heating plates disposed on both sides of the flat coil and forming a flow path therebetween;
    An induction heating apparatus comprising: a high-frequency power source that supplies a high-frequency current to the flat coil.
11. The induction heating apparatus according to claim 10, wherein the heating plate is formed in a wave shape.
12. The flat coil is housed in a metal case made of a metal material,
    The induction heating apparatus according to any one of claims 1 to 11, wherein the metal case has a slit extending in substantially the same direction as a direction of magnetic flux generated in the flat coil.
13. A hot air generator using the induction heating device according to any one of claims 1 to 12.
14. A hand dryer using the induction heating device according to any one of claims 1 to 12.
15. Equipped with a manual insertion part, and a front side duct and a rear side duct provided on the front side and the rear side of the manual insertion part, an air flow is ejected from the front side and back side ducts to remove water droplets attached to the hand In the hand dryer that
    A hand-drying device comprising the induction heating device according to any one of claims 1 to 12 provided on each of the front-side and back-side ducts.
16. 15. The hand dryer according to claim 14, wherein the induction heating device provided in the front side duct supplies more power than the induction heating device provided in the back side duct.

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