Electromagnetic induction heating device and linked type electromagnetic induction heating device

Abstract

To provide an electromagnetic induction heating device with a simple structure and high efficiency. [Solution] An electromagnetic induction heating device 100 is configured so that multiple permanent magnets 7 fixed to a rotating shaft 5 are surrounded by an internal cylindrical member 20 of a metal case 8. Rotation of the permanent magnets 7 generates eddy currents in the internal cylindrical member 20, generating heat, and the generated heat is transferred to and heated by a fluid F flowing inside the metal case 8. This electromagnetic induction heating device 100 includes a drive means 12 that rotates the rotating shaft 5 to which multiple permanent magnets 7 are fixed along the rotation direction via magnet holders 6, and a metal case 8 in which the opposing side surfaces of the internal cylindrical member 20 and the external cylindrical member 21 form a flow path for the fluid F to be heated. The rotating shaft 5 passes through the internal cylindrical member 20 of the metal case 8 along its central axis, and the permanent magnets 7 are arranged so as to face the inner surface of the internal cylindrical member 20.

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic induction heating device suitable for heating a fluid. [Background technology]

[0002] Electromagnetic induction heating is an efficient heating method with little heat loss, as it does not involve combustion and does not produce combustion gases including carbon dioxide. Previously, inventions have been made that apply electromagnetic induction heating to fluid heating, such as the electromagnetic induction heating device described in Patent Document 1 below. This heating device has an electromagnetic induction coil, through which an alternating current flows, wound around a cylindrical body, the interior of which forms a flow path for the fluid to be heated. A metal heating element is disposed inside the cylindrical body, which generates heat by generating eddy currents due to magnetic flux generated by the electromagnetic induction coil. Heat from this heating element is then transferred to the fluid to be heated flowing through the flow path, thereby heating the fluid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-228438 Summary of the Invention [Problem to be solved by the invention]

[0004] The electromagnetic induction heating device described in Patent Document 1 uses a disk-shaped heating element, with multiple heating elements arranged along the longitudinal direction of a cylinder, to increase the area of ​​intersection between the magnetic flux and the heating element. This creates a complex structure with multiple heating elements built into the cylinder. While some effort has been made to increase the area of ​​intersection between the magnetic flux and the heating element, holes or gaps through which the heated fluid passes inside the cylinder are essential, placing certain limitations on increasing the area of ​​intersection.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic induction heating device that has a simple structure and is highly efficient. [Means for solving the problem]

[0006] In order to solve this problem, the invention described in claim 1 provides a heating device comprising: a driving means for rotating a rotating shaft to which a plurality of permanent magnets are fixed; and a metal case in which the opposing side surfaces of an inner cylindrical member and an outer cylindrical member form a flow path for a fluid to be heated; the rotating shaft passes through along the central axis of the inner cylindrical member; and the permanent magnets are disposed so as to face the inner surface of the inner cylindrical member. A heat sink is attached to the permanent magnet. It is characterized by:

[0007] The invention of claim 2 is characterized in that, in addition to the configuration described in claim 1, the permanent magnet is fixed to the rotating shaft via a magnet holder, and multiple permanent magnets are arranged in the magnet holder along the rotation direction of the rotating shaft.

[0008] The invention according to claim 3 is characterized in that, in addition to the configuration according to claim 2, a plurality of the magnet holders are attached to the rotating shaft.

[0009] The invention of claim 4 is characterized in that, in addition to the configuration described in claim 1 or 2, the flow path is formed in a spiral shape in which the heated fluid flows along the circumferential direction of the metal case while progressing in the longitudinal direction.

[0010] The invention of claim 5 is characterized in that, in addition to the configuration of claim 1 or 2, it further comprises a rotation speed control unit that controls the rotation speed of the rotating shaft so as to maintain the temperature of the heated fluid discharged from the metal case at a set temperature after heating.

[0011] The invention of claim 6 is characterized in that, in addition to the configuration described in claim 5, the rotational speed control unit controls the rotational speed of the rotating shaft so that the temperature of the metal case does not exceed a predetermined maximum temperature.

[0012] The invention of claim 7 is characterized in that, in addition to the configuration described in claim 1 or 2, a blower means for generating an air flow in the inner space formed by the inner surface of the inner tubular member of the metal case is attached to the rotating shaft.

[0014] Claim 8 The invention relates to: In addition to the configuration as set forth in claim 1 or 2, The inner and outer cylindrical members are each a hollow cylindrical member.

[0015] Claim 9 The invention according to the claim Section 2 In addition to the configuration described above, the permanent magnets are arranged so that the N poles and S poles of the permanent magnets adjacent to each other along the rotation direction are alternately switched.

[0016] Claim 10 The invention according to claim 1 is a linked electromagnetic induction heating device configured using a plurality of electromagnetic induction heating devices according to claim 1 or 2, characterized in that an outlet for the heated fluid provided in the metal case of one of the electromagnetic induction heating devices is connected to a supply port for the heated fluid provided in the metal case of another of the electromagnetic induction heating devices by a connecting flow path, and the heated fluid discharged from the outlet passes through the connecting flow path and is supplied to the supply port, and is also heated by the other of the electromagnetic induction heating devices. [Effects of the Invention]

[0017] According to the invention of claim 1, multiple permanent magnets facing the inner surface of the internal cylindrical member of the metal case rotate, generating eddy currents in the internal cylindrical member, which then generate heat. This heat is then transferred to the fluid to be heated that flows through the flow path formed by the internal cylindrical member and the external cylindrical member, thereby heating the fluid. In this way, electromagnetic induction heating is achieved with a simple structure in which a rotating shaft with permanent magnets attached is inserted through the internal cylindrical member.

[0018] Furthermore, because the permanent magnets face the inner surface of the internal cylindrical member, most of the magnetic flux generated by the permanent magnets intersects with the internal cylindrical member, which reduces loss and generates heat efficiently.

[0019] Furthermore, although the magnetic force of permanent magnets decreases as the temperature rises, the heat is absorbed by the air as the magnets rotate, preventing the temperature rise of the magnets and maintaining efficiency even when the magnets are operated for long periods of time.

[0020] According to the invention of claim 2, multiple permanent magnets are arranged along the rotation direction of the rotating shaft, so the number of changes in the magnetic flux that intersects with the metal case due to the rotation of the rotating shaft increases by the number of permanent magnets, thereby increasing the amount of heat generated.

[0021] According to the invention of claim 3, multiple magnet holders to which multiple permanent magnets are fixed are attached in the axial direction of the rotating shaft, so that the change in magnetic flux caused by the rotation of the rotating shaft occurs over a wide area of ​​the metal case, causing the metal case to heat up as a whole. This increases the area over which heat transfers to the heated fluid, resulting in efficient heating. In addition, as the number of permanent magnets increases, the amount of heat generated also increases.

[0022] According to the invention of claim 4, the flow path through which the heated fluid flows inside the metal case is formed in a spiral shape. This increases the contact area between the heated fluid and the metal case, allowing for efficient transfer of heat from the metal case to the heated fluid.

[0023] According to the invention of claim 5, the fluid to be heated can be heated to a desired set temperature by controlling the rotation speed of the rotating shaft. This is because by controlling the rotation speed of the rotating shaft, the amount of heat generated can be controlled, and therefore the temperature of the fluid to be heated can be controlled.

[0024] According to the invention of claim 6, the temperature of the metal case is controlled so as not to exceed a predetermined maximum temperature. It is assumed that the temperature of the permanent magnet rises as the temperature of the metal case rises, and this measure prevents the temperature of the permanent magnet from becoming too high. This prevents deterioration of the permanent magnet due to high temperatures and leads to a longer lifespan.

[0025] According to the invention of claim 7, an air flow is generated in the inner space of the metal case in which the rotating shaft is disposed, and this air flow acts to cool the temperature of the permanent magnet. This suppresses the temperature rise of the permanent magnet and prevents a decrease in magnetic force due to high temperature. Because the air blowing means generates the air flow using the rotation of the rotating shaft, there is no need to provide a separate power source to operate the air blowing means.

[0026] Claim 1 According to this invention, a heat sink is attached to the permanent magnet, and heat dissipation suppresses the temperature rise of the permanent magnet. This prevents the magnetic force of the permanent magnet from decreasing due to high temperatures. The rotation of the rotating shaft creates an air flow around the heat sink, improving heat dissipation efficiency.

[0027] Claim 8 According to the invention, since the internal cylindrical member of the metal case is hollow cylindrical, the distance between the opposing permanent magnet and the inner surface of the internal cylindrical member is kept constant even when the rotating shaft rotates. The distance between the permanent magnet and the internal cylindrical member can be shortened over the entire circumference, allowing the magnetic flux generated by the permanent magnet to efficiently cross the internal cylindrical member. This improves the heat generation efficiency of the internal cylindrical member of the metal case.

[0028] Furthermore, since the inner and outer cylindrical members of the metal case are hollow cylindrical, they are easy to process and manufacturing costs can be reduced.

[0029] Claim 9 According to this invention, the north and south poles of adjacent permanent magnets are arranged so that they alternate along the rotation direction of the rotating shaft, which increases the amount of change in magnetic flux due to the rotation of the rotating shaft and improves heat generation efficiency.

[0030] Claim 10 According to the invention, a plurality of electromagnetic induction heating devices are connected via connecting flow paths. Since the fluid to be heated is heated by the plurality of electromagnetic induction heating devices, the temperature of the fluid to be heated can be rapidly increased. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic structural diagram of an electromagnetic induction heating device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the electromagnetic induction heating device according to the first embodiment taken along line AA. [Figure 3] 3 is a diagram showing a coupling structure between a permanent magnet and a magnet holder in the electromagnetic induction heating device according to the first embodiment. FIG. [Figure 4] 3 is a diagram showing a flow path for a fluid to be heated formed inside a metal case in the electromagnetic induction heating device according to the first embodiment. FIG. [Figure 5] 2 is a schematic diagram illustrating the configuration of an electromagnetic induction heating device according to the first embodiment installed in a heated swimming pool. FIG. [Figure 6] FIG. 10 is a diagram showing a structure in which a permanent magnet and a magnet holder are coupled via a heat sink in an electromagnetic induction heating device according to embodiment 2 of the present invention. [Figure 7] 10 is a schematic view showing a rotating shaft with a metal case removed in an electromagnetic induction heating device according to the second embodiment. FIG. [Figure 8] FIG. 10 is a schematic structural diagram of a linked type electromagnetic induction heating device according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a schematic structural diagram of a linked-type electromagnetic induction heating device according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a schematic structural diagram of an electromagnetic induction heating device according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] [First embodiment of the invention] A first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.

[0033] FIG. 1 is a schematic structural diagram of an electromagnetic induction heating device 100 according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA. This electromagnetic induction heating device 100 is configured so that a plurality of permanent magnets 7 fixed to a rotating shaft 5 are surrounded by an internal cylindrical member 20 of a metal case 8. Magnetic flux is generated from the permanent magnets 7, and as the permanent magnets 7 rotate, the magnetic flux that intersects with each region of the internal cylindrical member 20 changes, causing eddy currents due to electromagnetic induction in the internal cylindrical member 20, which then heats the internal cylindrical member 20. This heat is transferred to the fluid F to be heated flowing inside the metal case 8, thereby heating the fluid. The fluid F to be heated may be a liquid such as water or bio-oil, or a gas such as a catalytic gas.

[0034] The electromagnetic induction heating device 100 includes a driving means 12 that rotates a rotating shaft 5 to which multiple permanent magnets 7 are fixed along the rotation direction via magnet holders 6, and a metal case 8 in which the opposing sides of an inner cylindrical member 20 and an outer cylindrical member 21 form a flow path for the heated fluid F.

[0035] The driving means 12 is configured to include a driving power source motor 1, a driving pulley 2, a driven pulley 3, a rotating shaft 5, and a bearing 4 that supports the rotating shaft 5 for rotation.

[0036] A large-diameter drive pulley 2 is attached to the drive shaft of the drive power source motor 1, and is connected via a belt 13 to a small-diameter driven pulley 3 fixed to the rotating shaft 5. Due to the difference in diameter between the drive pulley 2 and the driven pulley 3, the rotation of the drive shaft of the drive power source motor 1 is amplified and transmitted to the driven pulley 3.

[0037] A magnet holder 6, to which multiple permanent magnets 7 are fixed along the direction of rotation, is attached to the rotating shaft 5 to which the rotation of the driven pulley 3 is transmitted. The cross section of this magnet holder 6, perpendicular to the axial direction of the rotating shaft 5, is octagonal, and a permanent magnet 7 is fixed to each face forming the octagon. The shape of the magnet holder 6 does not have to be octagonal in cross section, and may be hexagonal or decagonal, for example. Increasing the number of permanent magnets 7 fixed in the direction of rotation of the rotating shaft 5 increases the number of cycles of change in magnetic flux that occur during one rotation, and therefore the amount of heat generated.

[0038] It is preferable to select a type of permanent magnet 7 that has a strong magnetic force, such as a neodymium magnet.

[0039] 1 shows an example in which two magnet holders 6 are attached to the rotating shaft 5, but the number of magnet holders 6 attached along the axial direction may be increased to six or eight, etc. Increasing the number of magnet holders 6 also increases the amount of heat generated.

[0040] The rotating shaft 5 passes through the internal cylindrical member 20 of the metal case 8 along the central axis, and the magnet holder 6 is disposed so as to be housed in the internal space 29 formed by the internal surface of the internal cylindrical member 20 of the metal case 8. When the permanent magnet 7 fixed to the magnet holder 6 faces the internal surface of the internal cylindrical member 20 of the metal case 8 and the rotating shaft 5 rotates, the magnetic flux that intersects each region of the internal cylindrical member 20 changes, generating eddy currents and causing the internal cylindrical member 20 to heat up.

[0041] The metal case 8 is formed by joining the inner cylindrical member 20, the outer cylindrical member 21, and the case end members 22 that form both end faces by welding or the like to form an airtight space to prevent leakage of the internal fluid. In this embodiment, the metal case 8 is formed by coaxially arranging the hollow cylindrical outer cylindrical member 21 so as to surround the outer side surface 25 of the hollow cylindrical inner cylindrical member 20, and joining the doughnut-shaped disk-shaped case end members 22 to both end faces of the hollow cylindrical outer cylindrical member 21. By forming the inner cylindrical member 20 into a hollow cylindrical shape, the distance between the opposing permanent magnet 7 and the inner surface of the inner cylindrical member 20 is maintained constant even when the rotating shaft 5 rotates. This allows the distance between the permanent magnet 7 and the inner cylindrical member 20 to be short over the entire circumference, allowing the magnetic flux generated by the magnet 7 to efficiently intersect with the inner cylindrical member 20. This improves the heat generation efficiency of the inner cylindrical member 20 of the metal case 8.

[0042] The material of the internal cylindrical member 20 may be either a non-magnetic metal material or a magnetic metal material, as long as it generates heat by generating eddy currents due to electromagnetic induction. For example, aluminum, an aluminum alloy, stainless steel, etc. are used. In many cases, the entire metal case 8, including the internal cylindrical member 20, the external cylindrical member 21, and the case end members 22, is made of the same material.

[0043] The opposing side surfaces of the inner cylindrical member 20 and the outer cylindrical member 21, that is, the outer side surface 25 of the inner cylindrical member 20 and the inner side surface 26 of the outer cylindrical member 21, form a flow path for the fluid F to be heated.

[0044] In addition, a supply port 9 is provided below one of the case end surface members 22 that form both end surfaces of the metal case 8, through which the heated fluid F is supplied into the metal case 8 before heating, and a discharge port 10 is provided above the other case end surface member 22, through which the heated fluid F is discharged after heating.

[0045] The fluid to be heated F supplied from the supply port 9 is preferably sent into the metal case 8 using a pump 30 or the like. By imparting a flow velocity to the fluid to be heated F, the fluid to be heated F inside the metal case 8 is mixed, and uniform heating can be performed without bias in the temperature distribution.

[0046] A supply port thermometer 14 is installed at the supply port 9 of the metal case 8 to measure the temperature of the heated fluid F before heating, and a discharge port thermometer 15 is installed at the discharge port 10 to measure the temperature of the heated fluid F after heating. A metal case thermometer 16 is also installed to measure the temperature of the metal case 8.

[0047] As the rotation speed of the rotating shaft 5 increases, the rate of change in the magnetic flux with respect to time (time derivative of the magnetic flux) increases, and therefore the eddy current generated in the inner cylindrical member 20 increases, increasing the amount of heat generated.

[0048] The drive power source motor 1 is connected to a rotation speed control unit 11 serving as a "rotation speed control section" that controls the rotation speed of the rotary shaft 5 so as to maintain the fluid F to be heated at a set temperature.

[0049] The rotation speed control unit 11 includes a central processing unit (CPU), a nonvolatile flash memory, and a volatile random access memory (RAM), and the CPU executes a temperature control program stored in the flash memory. This control program changes the rotation speed of the drive power source motor 1 so that the temperature of the heated fluid F discharged from the outlet 10 after heating matches the set temperature. For example, the control program references the temperature of the heated fluid F before heating measured by the supply port thermometer 14 and the temperature of the heated fluid F after heating measured by the outlet port thermometer 15. If the temperature of the heated fluid F after heating is lower than the set temperature, the rotation speed of the rotating shaft 5 is increased; if the temperature of the heated fluid F before heating is higher, the rotation speed is decreased. Furthermore, if there is a fluctuation in the temperature of the heated fluid F before heating, the rotation speed of the rotating shaft 5 is controlled to counteract the fluctuation. That is, if the temperature of the heated fluid F before heating increases, the rotation speed is decreased; if the temperature of the heated fluid F before heating decreases, the rotation speed is increased. In other words, the difference between the temperature of the outlet thermometer 15 and the temperature of the supply thermometer 14, and the temperature of the outlet thermometer 15, are used to adjust the rotation speed of the rotating shaft 5 so that the temperature of the heated fluid F after heating matches the set temperature.

[0050] The rotation speed can be controlled using well-known techniques. For example, when a three-phase AC motor is used as the drive power source motor 1, control can be performed using an inverter. When a DC motor is used, the rotation speed can be controlled by changing the drive voltage. Alternatively, a brake mechanism can be provided on the rotating shaft 5 to mechanically apply a braking force to control the rotation speed. In most cases, the set temperature is input by the user of the electromagnetic induction heating device 100.

[0051] Furthermore, the rotation speed control unit 11 controls the rotation speed of the rotating shaft 5 so that the temperature of the metal case 8 measured by the metal case thermometer 16 does not exceed a predetermined maximum temperature, such as 230°C or 250°C. As the temperature of the metal case 8 rises, it is assumed that the temperature of the permanent magnet 7 also rises, and this is a measure to prevent the temperature of the permanent magnet 7 from becoming too high. This prevents deterioration of the permanent magnet 7 due to high temperatures, leading to a longer lifespan.

[0052] The AA cross section shown in Fig. 2 is taken along a plane parallel to the direction of rotation of the rotary shaft 5 and including the permanent magnet 7. Although not present within this cross section, a discharge port 10 provided in the case end member 22 of the metal case 8, which faces the supply port 9 provided in the case end member 22, is indicated by a dashed line.

[0053] An outer side surface 25 of the inner cylindrical member 20 of the metal case 8 and an inner side surface 26 of the outer cylindrical member 21 form a flow path for the heated fluid F. A rotating shaft 5 having eight permanent magnets 7 fixed thereto is disposed along the rotation direction in an inner space 29 formed by the inner side surface 28 of the inner cylindrical member 20, which serves as the inner surface of the inner cylindrical member 20.

[0054] The rotating shaft 5 has a hollow structure with a space in the center, which reduces its weight. This is because reducing the weight of the rotating shaft 5 reduces energy loss associated with rotational driving. The rotating shaft 5 is made of a high-strength material such as stainless steel or aluminum alloy.

[0055] A magnet holder 6 with an octagonal cross section is attached to the rotating shaft 5. The rotating shaft 5 and magnet holder 6 are attached by fastening with bolts or welding. The magnet holder 6 is made of a non-magnetic metal material such as non-magnetic high-strength stainless steel or aluminum alloy.

[0056] Permanent magnets 7 are fixed to each face forming the octagon of the magnet holder 6 by fastening with bolts 45. The permanent magnets 7 fixed to the magnet holder 6 are arranged so that the north and south poles of adjacent permanent magnets 7 alternate in the direction of rotation. By arranging the magnetic poles alternately, the amount of change in magnetic flux that occurs with the rotation of the rotating shaft 5 increases, and the amount of heat generated increases. However, there are no restrictions on the arrangement of the magnetic poles of adjacent permanent magnets 7 and it can be freely selected.

[0057] The eight permanent magnets 7 fixed to the magnet holder 6 are arranged to face the inner side surface 28, which is the inner surface of the inner cylindrical member 20 of the metal case 8. The closer the permanent magnets 7 are to the inner cylindrical member 20, the more the magnetic flux generated from the permanent magnets 7 intersects with the inner cylindrical member 20 without loss, resulting in higher heat generation efficiency.

[0058] Figure 3 shows the connection structure between the permanent magnet 7 and magnet holder 6. The permanent magnet 7 is a hollow cylinder with a space formed along its central axis. The magnet holder 6 has a female-threaded screw hole 46, and a male-threaded bolt 45 is passed through the central axis of the permanent magnet 7 and tightened into the screw hole 46 in the magnet holder 6. The permanent magnet 7 is fixed by being sandwiched between the head of the bolt 45 and the magnet holder 6.

[0059] FIG. 4 is a diagram showing the flow path of the fluid F to be heated formed inside the metal case 8. This diagram represents the interior of the metal case 8 when it is assumed that the outer cylindrical member 21 of the metal case 8 is transparent. A flow path forming plate 17 is provided to partition the airtight space between the inner cylindrical member 20 and the outer cylindrical member 21 of the metal case 8 and form a flow path. The flow path formed by this flow path forming plate 17 has a spiral shape in which the fluid F to be heated flows around the circumferential direction of the metal case 8 and advances in the longitudinal direction from one case end surface member 22 provided with the supply port 9 to the other case end surface member 22 provided with the discharge port 10. By forming the flow path in a spiral shape, the contact area between the fluid F to be heated and the metal case 8 is increased, thereby efficiently transferring heat from the metal case 8 to the fluid F to be heated.

[0060] 4 shows an example in which the flow path is formed by a flow path forming plate 17, but a pipe formed in a spiral shape may be used instead of the flow path forming plate 17. It is preferable to form the flow path in a spiral shape, but the flow path forming plate 17 may not be provided and the heated fluid F may be allowed to flow freely in the airtight space between the inner cylindrical member 20 and the outer cylindrical member 21.

[0061] 5 is a schematic diagram showing the configuration of an electromagnetic induction heating device 100 installed in a heated swimming pool 32. The fluid F to be heated is water, and the electromagnetic induction heating device 100 heats the water in the heated swimming pool 32 while controlling the water temperature to be maintained at a predetermined target temperature.

[0062] Water in the heated pool 32 is supplied by a pump 30 to a supply port 9 of the electromagnetic induction heating device 100 and introduced into the metal case 8. A drive power source motor 1 rotates a rotating shaft 5, causing the permanent magnets 7 facing the inner side surface 28 of the inner cylindrical member 20 of the metal case 8 to rotate. The rotation speed of the rotating shaft 5 is set, for example, in a range of approximately 0 to 3,000 revolutions per minute. Focusing on a certain region on the inner cylindrical member 20 and observing the magnetic flux intersecting that region, changes in the magnetic flux occur as the permanent magnets 7 rotate. Electromagnetic induction caused by this change in magnetic flux generates eddy currents in the inner cylindrical member 20, generating heat. The heat generated in the inner cylindrical member 20 transfers to the water flowing inside the metal case 8, raising the temperature.

[0063] The water heated in this way is discharged from the outlet 10 provided in the case end member 22 and returned to the heated pool 32. The inflow of heated water increases the water temperature of the heated pool 32. A pool thermometer 33 is installed in the heated pool 32, and water temperature data is notified to the rotational speed control unit 11 of the electromagnetic induction heating device 100.

[0064] The rotation speed control unit 11 compares the notified water temperature data with a predetermined target temperature, and changes the set temperature set in the temperature control program so that the water temperature measured by the pool thermometer 33 matches the target temperature. Accordingly, the rotation speed of the drive power source motor 1 is changed to control the rotation speed of the rotating shaft 5.

[0065] Next, the effects of the first embodiment of the present invention will be described.

[0066] According to the first embodiment, the multiple permanent magnets 7 facing the inner surface (inner side surface 28) of the internal cylindrical member 20 of the metal case 8 rotate, generating eddy currents in the internal cylindrical member 20 and generating heat. Heat is then transferred to the fluid F to be heated that flows through the flow path formed by the internal cylindrical member 20 and the external cylindrical member 21, thereby performing heating. In this way, electromagnetic induction heating is achieved with a simple structure in which the rotating shaft 5, to which the permanent magnets 7 are attached, is inserted through the internal cylindrical member 20.

[0067] Furthermore, since the permanent magnet 7 faces the inner surface of the internal cylindrical member 20, most of the magnetic flux generated from the permanent magnet 7 intersects with the internal cylindrical member 20. This reduces loss and generates heat efficiently.

[0068] Furthermore, as the temperature of the permanent magnet 7 rises, the magnetic force decreases, but as heat is absorbed by the air during rotation, the temperature rise of the magnet 7 is suppressed, and efficiency is maintained even during long-term operation.

[0069] Furthermore, according to the present embodiment 1, multiple permanent magnets 7 are arranged along the rotational direction of the rotating shaft 5, and therefore the number of changes in the magnetic flux that intersects with the metal case 8 due to the rotation of the rotating shaft 5 increases by the number of permanent magnets 7, thereby increasing the amount of heat generated.

[0070] Furthermore, according to the first embodiment, a plurality of magnet holders 6, to which a plurality of permanent magnets 7 are fixed, are attached in the axial direction of the rotating shaft 5, so that the change in magnetic flux due to the rotation of the rotating shaft 5 occurs over a wide area of ​​the metal case 8, and the metal case 8 generates heat overall. This increases the area over which heat transfers to the heated fluid F, and heating is performed efficiently. Furthermore, as the number of permanent magnets 7 increases, the amount of heat generated also increases.

[0071] Furthermore, according to the first embodiment, the flow path through which the fluid to be heated F flows inside the metal case 8 is formed in a spiral shape. Since the contact area between the fluid to be heated F and the metal case 8 increases, heat is efficiently transferred from the metal case 8 to the fluid to be heated F.

[0072] Furthermore, according to the first embodiment, the fluid to be heated F can be heated to a desired set temperature by controlling the rotation speed of the rotating shaft 5. This is because by controlling the rotation speed of the rotating shaft 5, the amount of heat generated can be controlled, and therefore the temperature of the fluid to be heated F can be controlled.

[0073] Furthermore, according to the first embodiment, the temperature of the metal case 8 is controlled so as not to exceed a predetermined maximum temperature. It is assumed that the temperature of the permanent magnet 7 also rises as the temperature of the metal case 8 rises, and this is a measure to prevent the temperature of the permanent magnet 7 from becoming too high. This prevents deterioration of the permanent magnet 7 due to high temperatures, leading to a longer lifespan.

[0074] Furthermore, according to the first embodiment, since the internal cylindrical member 20 of the metal case 8 has a hollow cylindrical shape, the distance between the opposing permanent magnet 7 and the inner surface (inner side surface 28) of the internal cylindrical member 20 is kept constant even when the rotating shaft 5 rotates. The distance between the permanent magnet 7 and the internal cylindrical member 20 can be shortened over the entire circumference, allowing the magnetic flux generated by the permanent magnet 7 to efficiently intersect with the internal cylindrical member 20. This improves the heat generation efficiency of the internal cylindrical member 20 of the metal case 8.

[0075] Furthermore, since the inner cylindrical member 20 and the outer cylindrical member 21 of the metal case 8 are hollow cylindrical, they are easy to process and manufacturing costs can be reduced.

[0076] Furthermore, according to this embodiment 1, the N and S magnetic poles of adjacent permanent magnets 7 are arranged so as to alternate along the rotation direction of the rotating shaft 5, thereby increasing the amount of change in magnetic flux due to the rotation of the rotating shaft 5 and improving heat generation efficiency.

[0077] [Embodiment 2 of the Invention] A second embodiment of the present invention will be described with reference to Figures 6 and 7. However, elements that are the same as or correspond to those in the electromagnetic induction heating device 100 according to the first embodiment are given the same reference numerals, and duplicated explanations will be omitted.

[0078] The electromagnetic induction heating device 100 according to the second embodiment is obtained by adding a cooling means for cooling the permanent magnets 7 fixed to the rotating shaft 5 to the configuration of the electromagnetic induction heating device 100 according to the first embodiment described above.

[0079] This cooling means is composed of a heat sink 40 attached to the permanent magnet 7 and propeller blades 42 as "air blowing means" attached to the rotating shaft 5. The propeller blades 42 rotate together with the rotating shaft 5, and generate an air flow in the inner space 29 formed by the inner surface (inner side surface 28) of the inner cylindrical member 20 of the metal case 8.

[0080] When the permanent magnet 7 fixed to the rotating shaft 5 rotates within the inner space 29 of the metal case 8 and the metal case 8 generates heat, the temperature of the permanent magnet 7 also rises. As the temperature rises, the magnetic force of the permanent magnet 7 weakens and the eddy current caused by electromagnetic induction also decreases. As a result, the heat generation efficiency of the metal case 8 decreases. It is also expected that high temperatures will accelerate deterioration of the permanent magnet 7 and shorten its lifespan. For this reason, it is preferable to suppress the temperature rise of the permanent magnet 7.

[0081] In the electromagnetic induction heating device 100 according to the second embodiment, the temperature rise of the permanent magnet 7 is suppressed by heat dissipation from the heat sink 40 attached to the permanent magnet 7 and the air-cooling effect of the air flow within the inner space 29 created by the propeller blades 42, which removes heat from the permanent magnet 7.

[0082] Fig. 6 is a diagram showing a structure in which a permanent magnet 7 and a magnet holder 6 are coupled via a heat sink 40. Compared to the coupled structure of the permanent magnet 7 and the magnet holder 6 shown in Fig. 3, Fig. 6 differs in that a heat sink 40 sandwiched between the permanent magnet 7 and the magnet holder 6 is added.

[0083] A plurality of pin-shaped heat dissipation fins 41 are provided on the surface of a base plate 47 of this heat sink 40. A single circular hole 48 through which a bolt 45 passes is formed in the center of the base plate 47. The area around this circular hole 48, where no heat dissipation fins 41 are provided, forms a magnet mounting surface 49 on which a permanent magnet 7 is mounted. Because the permanent magnet 7 is fixed in contact with this magnet mounting surface 49, heat from the permanent magnet 7 is transferred from the magnet mounting surface 49 to the entire heat sink 40 and dissipated from the entire surface of the heat sink 40, including the heat dissipation fins 41. To improve heat dissipation efficiency, the width of the base plate 47 of the heat sink 40 may be wider than the thickness of the magnet holder 6. The heat dissipation fin 41 may be pin-shaped or plate-shaped.

[0084] When fixing the permanent magnet 7 to the magnet holder 6, a bolt 45 is passed through the central axis of the permanent magnet 7 and the round hole 48 of the heat sink 40 and then fastened to a screw hole 46 of the magnet holder 6 to join them.

[0085] The heat sink 40 is made of a material with high thermal conductivity, such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0086] The rotation of the rotary shaft 5 generates a relative air flow around the heat sink 40, which allows for efficient heat dissipation.

[0087] 7 is a schematic diagram showing the rotating shaft 5 with the metal case 8 removed, where the position of the metal case 8 is shown imaginarily by a dashed line.

[0088] A permanent magnet 7 is fixed via a heat sink 40 to each surface of the magnet holder 6 attached to the rotating shaft 5. Three propeller blades 42 are also attached to the rotating shaft 5. These three propeller blades 42 are disposed between both entrance portions of the inner surface space 29 formed by the metal case 8 (both end portions of the metal case 8) and the two magnet holders 6.

[0089] As the rotating shaft 5 rotates, the propeller blades 42 generate an air flow in the inner space 29 of the metal case 8, and this air removes heat from the permanent magnets 7, thereby suppressing a rise in temperature of the permanent magnets 7. The rotation of the propeller blades 42 and the rotating shaft 5 functions as an axial flow fan. The propeller blades 42 are made of a lightweight material such as aluminum or an aluminum alloy.

[0090] The positions at which the propeller blades 42 are attached and the number of the propeller blades 42 may be determined arbitrarily.

[0091] The second embodiment also provides the same effects as the first embodiment.

[0092] Furthermore, according to the second embodiment, an air flow is generated in the inner surface space 29 of the metal case 8 in which the rotating shaft 5 is disposed, and this air flow acts to cool the temperature of the permanent magnets 7. This suppresses the temperature rise of the permanent magnets 7 and prevents a decrease in magnetic force due to high temperatures. Because the propeller blades 42 generate the air flow using the rotation of the rotating shaft 5, there is no need to provide a separate power source for rotating the propeller blades 42.

[0093] Furthermore, according to the second embodiment, the heat sink 40 is attached to the permanent magnet 7, and heat dissipation suppresses a temperature rise of the permanent magnet 7. This prevents a decrease in the magnetic force of the permanent magnet 7 due to high temperatures. The rotation of the rotating shaft 5 generates an air flow around the heat sink 40, improving heat dissipation efficiency.

[0094] Third Embodiment Embodiment 3 of the present invention will be described with reference to Fig. 8. However, elements that are the same as or correspond to those of the electromagnetic induction heating device 100 according to embodiment 1 or 2 will be given the same reference numerals, and duplicated explanations will be omitted.

[0095] 8 is a schematic structural diagram of a linked electromagnetic induction heating device 200 according to embodiment 3 of the present invention. This linked electromagnetic induction heating device 200 is configured using a plurality of electromagnetic induction heating devices 100 according to embodiment 1 or 2, and an outlet 10 provided in the metal case 8 of one of the plurality of electromagnetic induction heating devices 100 is connected to a supply port 9 provided in the metal case 8 of another electromagnetic induction heating device 100 by a connecting flow path 50. The heated fluid F discharged from the outlet 10 of one electromagnetic induction heating device 100 passes through the connecting flow path 50 and is supplied to the supply port 9 of the other electromagnetic induction heating device 100, and is also heated by the other electromagnetic induction heating device 100.

[0096] Since the fluid F to be heated is heated by a plurality of electromagnetic induction heating devices 100, a rapid temperature rise can be achieved.

[0097] Although FIG. 8 shows a configuration in which two electromagnetic induction heating devices 100 are connected together, three or more devices may be connected together to form a connected electromagnetic induction heating device 200.

[0098] Furthermore, one rotational speed control unit 11 may control a plurality of electromagnetic induction heating devices 100 that constitute the linked-type electromagnetic induction heating device 200.

[0099] [Fourth embodiment of the invention] A fourth embodiment of the present invention will be described with reference to Fig. 9. However, elements that are the same as or correspond to those in the electromagnetic induction heating device 100 according to the first or second embodiment and the linked-type electromagnetic induction heating device 200 according to the third embodiment will be given the same reference numerals, and redundant explanations will be omitted.

[0100] 9 is a schematic structural diagram of a linked electromagnetic induction heating device 200A according to embodiment 4 of the present invention. This linked electromagnetic induction heating device 200A is a modification of the linked electromagnetic induction heating device 200 according to embodiment 3, in which two electromagnetic induction heating devices 100 are driven by a single drive power source motor 1.

[0101] Of the two electromagnetic induction heating devices 100 constituting the linked-type electromagnetic induction heating device 200 according to embodiment 3, the drive power source motor 1 is removed from one electromagnetic induction heating device 100A, and a large-diameter drive pulley 2 is added to the drive shaft of the other electromagnetic induction heating device 100. That is, two large-diameter drive pulleys 2 are attached to the drive shaft. One of the two drive pulleys 2 is connected via a belt 13 to a small-diameter driven pulley 3 of the electromagnetic induction heating device 100A from which the drive power source motor 1 has been removed, and rotates the rotating shaft 5. The other of the two drive pulleys 2 is connected via a belt 13 to the driven pulley 3 of the electromagnetic induction heating device 100, and rotates the rotating shaft 5.

[0102] The drive means 12A of the electromagnetic induction heating device 100A from which the drive power source motor 1 has been removed is configured to include the drive power source motor 1 of the other electromagnetic induction heating device 100, the drive pulley 2, driven pulley 3, rotating shaft 5 of the electromagnetic induction heating device 100A from which the drive power source motor 1 has been removed, and a bearing 4 that supports the rotation of this rotating shaft 5.

[0103] According to the fourth embodiment of the present invention, a single drive power source motor 1 drives a plurality of electromagnetic induction heating devices 100, 100A, thereby achieving cost reduction.

[0104] Fifth Embodiment A fifth embodiment of the present invention will be described with reference to Fig. 10. However, elements that are the same as or correspond to those of the electromagnetic induction heating device 100 according to the first or second embodiment will be given the same reference numerals, and duplicated explanations will be omitted.

[0105] FIG. 10 is a schematic structural diagram of an electromagnetic induction heating device 100B according to embodiment 5 of the present invention. In the electromagnetic induction heating device 100 according to embodiment 1 or 2, a drive pulley 2, a driven pulley 3, and a belt 13 are used to transmit power between the drive power source motor 1 and the rotating shaft 5. In the electromagnetic induction heating device 100B according to embodiment 5, power is transmitted from the drive power source motor 1 to the rotating shaft 5 using a drive gear 60 and a driven gear 61. That is, a large-diameter drive gear 60 attached to the drive shaft of the drive power source motor 1 and a small-diameter driven gear 61 attached to the rotating shaft 5 mesh with each other, and the rotation of the drive shaft of the drive power source motor 1 is transmitted to the rotating shaft 5. A driving means 12B with this configuration includes the drive power source motor 1, the drive gear 60, the driven gear 61, the rotating shaft 5, and the bearing 4 that rotationally supports the rotating shaft 5.

[0106] The drive gear 60 and driven gear 61, which are power transmission elements, may be configured as a speed change gear 62. When using the speed change gear 62, the rotational speed control unit 11 adjusts the rotational speed of the drive power source motor 1 and selects the speed change gear, thereby controlling the rotational speed of the rotating shaft 5 to keep the heated fluid F at the set temperature.

[0107] According to the fifth embodiment of the present invention, the use of the driving gear 60 and the driven gear 61 enables high-speed power transmission and high torque transmission.

[0108] The above-described first to fifth embodiments do not limit the present invention, and can be modified as appropriate within the scope of the gist of the invention.

[0109] For example, in the above-described embodiments 1 to 5, a rotating shaft 5 is used in which the cross-sectional shape of the side surface of the rotating shaft 5 when cut along a plane perpendicular to the axial direction is circular. However, a rotating shaft 5 having a polygonal cross-sectional shape of the side surface may be used, and a screw hole 46 may be provided on the side surface of the rotating shaft 5, and the permanent magnet 7 may be fastened with a bolt 45.

[0110] Furthermore, in the above-described embodiments 1 to 5, the shape of the inner cylindrical member 20 and the outer cylindrical member 21 of the metal case 8 is a hollow cylindrical shape in which the cross-sectional shape when cut along a plane perpendicular to the central axis is circular, but they may also be formed into a hollow polygonal column shape in which the cross-sectional shape is polygonal. [Explanation of symbols]

[0111] 100, 100A, 100B... electromagnetic induction heating device, 200, 200A... linked type electromagnetic induction heating device, 1... driving power source motor, 2... driving pulley, 3... driven pulley, 4... bearing, 5... rotating shaft, 6... magnet holder, 7... permanent magnet, 8... metal case, 9... supply port, 10... discharge port, 11... rotation speed control unit, 12, 12A, 12B... driving means, 13... belt, 14... supply port thermometer, 15... discharge port thermometer, 16... thermometer for metal case, 17... flow path forming plate, 40... heat sink, 41... heat dissipation fan fin, 42...propeller blade (air blowing means), 45...bolt, 46...screw hole, 47...base plate, 48...round hole, 49...magnet installation surface, 50...connecting flow path, 30...pump, 32...heated water pool, 33...pool thermometer, 20...inner tubular member, 21...outer tubular member, 22...case end surface member, 25...outer side surface of inner tubular member, 26...inner side surface of outer tubular member, 28...inner side surface of inner tubular member (inner surface of inner tubular member), 29...inner surface space, 60...drive gear, 61...driven gear, 62...speed change gear device, F...heated fluid

Claims

1. a driving means for rotating a rotation shaft to which a plurality of permanent magnets are fixed; a metal case in which the opposing side surfaces of the inner cylindrical member and the outer cylindrical member form a flow path for the fluid to be heated; An electromagnetic induction heating device characterized in that the rotating shaft passes through along the central axis of the internal cylindrical member, the permanent magnet is arranged to face the inner surface of the internal cylindrical member, and a heat sink is attached to the permanent magnet.

2. the permanent magnet is fixed to the rotating shaft via a magnet holder; 2. The electromagnetic induction heating device according to claim 1, wherein a plurality of the permanent magnets are arranged in the magnet holder along the rotation direction of the rotation shaft.

3. 3. The electromagnetic induction heating device according to claim 2, wherein a plurality of the magnet holders are attached to the rotating shaft.

4. 3. The electromagnetic induction heating device according to claim 1, wherein the flow path is formed in a spiral shape so that the fluid to be heated flows along the circumferential direction of the metal case while proceeding in the longitudinal direction.

5. 3. The electromagnetic induction heating device according to claim 1, further comprising a rotation speed control unit that controls the rotation speed of the rotating shaft so as to maintain the temperature of the heated fluid discharged from the metal case at a set temperature after heating.

6. 6. The electromagnetic induction heating device according to claim 5, wherein the rotation speed control unit controls the rotation speed of the rotating shaft so that the temperature of the metal case does not exceed a predetermined maximum temperature.

7. 3. The electromagnetic induction heating device according to claim 1, wherein a blower for generating an air flow in an inner space formed by the inner surface of the inner cylindrical member of the metal case is attached to the rotating shaft.

8. 3. The electromagnetic induction heating device according to claim 1, wherein the inner cylindrical member and the outer cylindrical member are hollow cylindrical.

9. 3. The electromagnetic induction heating device according to claim 2, wherein the permanent magnets are arranged so that the north and south poles of the permanent magnets adjacent to each other in the rotation direction are alternately switched.

10. A linked-type electromagnetic induction heating device configured using a plurality of electromagnetic induction heating devices according to claim 1 or 2, an outlet for the fluid to be heated provided in the metal case of one of the electromagnetic induction heating devices and a supply port for the fluid to be heated provided in the metal case of the other of the electromagnetic induction heating devices are connected by a connecting flow path; A linked electromagnetic induction heating device, characterized in that the heated fluid discharged from the outlet passes through the connecting flow path and is supplied to the supply port, where it is also heated by the other electromagnetic induction heating device.

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