JP6655165B2 - Inductors and inductor assemblies - Google Patents

Description

  The present invention relates to an inductor for induction heating, which includes a feed conductor and a return conductor, and a main winding part having at least one main winding having a first winding direction.

  The invention further provides an inductor assembly comprising at least two inductors for induction heating, the inductors each having a feed conductor and a return conductor, and at least one main winding having a first winding direction. The present invention relates to an inductor assembly having a winding part.

  Inductors of this type or similar are described, for example, in U.S. Pat. No. 3,108,169 (US Pat. No. 3,108,169); (US2007 / 0068457 A1).

  The invention further relates to a method for inductively heating a plurality of objects using a plurality of inductors, each connected to a separate excitation unit.

  Inductors find use in a variety of industrial applications, such as melting, evaporating or induction evaporating. Operation of adjacent inductors often causes disturbances in the generator, or excitation unit, because the inductors are magnetically coupled. This causes the connected generators to influence each other, and the output of the generator is thereby no longer arbitrarily controllable.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an inductor and an inductor assembly which enable satisfactory operation of two or more inductors which are arranged at a small distance from each other.

  According to a first aspect of the present invention, there is provided an inductor for induction heating, comprising: a feed conductor and a return conductor; and a main winding portion, wherein the main winding portion includes a first winding. An inductor having at least one main winding having a direction and having opposite ends connected to opposite ends of the main winding portion having a winding direction opposite to the first winding direction. You. The main winding part is directly connected to the reverse winding part by series connection. The reverse winding part and the main winding part are arranged concentrically with each other. At this time, both the reverse winding portion and the main winding portion have a substantially columnar shape. The main winding section has more turns than at least one reverse winding section. Thereby, the magnetic field of the opposite direction is superimposed on the magnetic field of the main winding. The propagation of the magnetic field in the main winding is changed in the space outside the inductor, especially at the reverse winding. This clearly reduces the stray magnetic field in the space outside the inductor. Mutual inductance between adjacent inductors is reduced.

  In this case, the main winding part is preferably suitable for induction heating of the object and is particularly configured accordingly. Preferably, the main winding has a sufficiently large inner diameter so that the object to be heated can be arranged inside.

  At least one reverse winding section may have one or more incomplete or complete turns. The incomplete winding or windings has the advantage that the working range of the reverse winding is adjustable. The configuration having a plurality of turns can enhance the effect of the reverse winding portion. In particular, the reverse winding can be designed to reduce stray magnetic fields in the space outside the inductor.

  The main winding part can be helically configured, in particular the main winding part can be helically configured with at least one reverse winding part. Alternatively, the main winding, or the main and reverse windings, may have a rectangular or square cross section. The main winding portion and the reverse winding portion may be conical or elliptical, or may have another shape. In particular, the main winding part and / or the reverse winding part can be formed so as to be suitable for accommodating a melting pot or an evaporation pot.

  Furthermore, a rectangular or square object to be heated may be accommodated with a certain connection gap.

  The at least one reverse winding may have at least the same or a larger diameter than the main winding. However, at this time, it is desirable that the main winding portion and the reverse winding portion maintain a substantially columnar shape. Due to the larger diameter of the reverse winding, the propagation of the magnetic field of the main winding in the space outside the inductor can be changed even more strongly.

  The main winding part can be connected to the at least one reverse winding part by a series connection. That is, the reverse winding part and the main winding part can be electrically connected in series. This has the advantage that the alternating current flowing in the main winding part also flows in the opposite winding part with the same phase, thereby maximally changing the propagation of the magnetic field of the main winding part in the space outside the inductor.

  The main winding section may have more turns than the at least one reverse winding section. This makes the inductor particularly suitable for performing induction heating.

  The feed conductor and the return conductor can be guided in parallel, in particular with a spacing of less than 1 cm. In particular, the distance between the feed conductor and the return conductor can be made as small as possible. An insulator can be disposed between the feed conductor and the return conductor. However, insulators other than air or vacuum are not required.

  By guiding the feed conductor and the return conductor in parallel, the length of the feed line can be limited. This results in less stray magnetic fields occurring in the feed line and correspondingly lower losses. Due to the small spacing between the feed conductor and the return conductor, the inductance of the feed line can be minimized. The stray magnetic field can be reduced. Similarly, voltage losses can be reduced. Furthermore, the undesired magnetic field of the feed line can be limited to as small a space as possible. Flashover can be avoided by using an insulator. In particular, the use of an insulator allows a predetermined spacing between the feed conductor and the return conductor to be realized.

  The feed conductor and / or the return conductor may be connected to the reverse winding by an inductor portion extending parallel to the longitudinal axis of the main winding. In particular, the inductor portion can extend substantially perpendicular to the feed and / or return conductors.

  In that case, the inductor part can be arranged outside the main winding part. Thereby, the object to be heated can be arranged in the main winding part without the inductor part being in the way.

  The inductor may have a coating to avoid corrosion. In particular, the coating may be a polymer.

  The inductor can be formed from a tube. Thereby, the inductor is suitable for flowing the cooling liquid, particularly the cooling water. Joule loss can be derived in this case by cooling water.

  The inductor can be formed from copper. This minimizes the ohmic resistance of the inductor. Joule losses in the cooling water of the inductor can thereby be minimized.

  The ends of the feed and return conductors can each be provided with one terminal for connection to the excitation unit. In that case, the excitation unit may have a device for supplying a cooling liquid, in particular cooling water. Correspondingly, the terminals for connection to the excitation unit can also be designed as terminals for the coolant.

  Via the terminals the inductor can be connected to a generator, in particular an excitation unit. With this, alternating current and cooling water can be supplied to the inductor via the terminal.

  Further within the scope of the present invention is an inductor assembly comprising at least two inductors for induction heating, the inductors each having a feed conductor and a return conductor, and a main winding portion, The part has at least one main winding having a first winding direction, and at least one end of the main winding part has a reverse winding part having a winding direction opposite to the first winding direction. Are connected, the inductors are each connected to an excitation unit, and the axes of the inductors are mutually connected, preferably of the diameter or the length of the inductor, depending on whether the diameter or the length of the inductor is larger. Inductor assemblies with spacing less than five times the value are included. The diameter means the diameter of the main winding. The length of the inductor is the axial length of the inductor including the reverse winding portion and the length of the main winding portion in the axial direction.

  Such an inductor assembly allows the inductors to be arranged relatively close to one another without significantly affecting the excitation unit connected to the inductor. This keeps the output of the excitation unit controllable.

  At least one of the inductors can be formed as an inductor according to the invention. That is, the opposite winding portions can be provided at both ends of the main winding portion.

  The feed and return conductors of the at least two inductors can extend parallel to each other. Thereby, the advantages achieved when the feed and return lines of one inductor run parallel to one another can be achieved.

  The terminals of the at least two inductors may be arranged in one connection plane. In particular, the main windings of the at least two inductors may be arranged at the same distance from the connection plane. The connection plane is a virtual plane existing at the beginning of the feed line of the inductor or at the end of the return line. The distance from the connection plane to the main winding of the inductor can be equal to or shorter than the length of the feed or return line.

  Alternatively or additionally, the main windings of the at least two inductors may be arranged at different distances from one another with respect to the connection plane.

  The at least one excitation unit has an external circuit having at least one capacitor, the external circuit such that the capacitor forms at least part of an oscillation circuit, in particular a parallel oscillation circuit, with an inductor connected to the excitation unit. It may be configured. The operation of the inductor in an oscillating circuit, in particular in a parallel oscillating circuit, allows the excitation unit to provide less current than the inductor current.

  The excitation units disposed on adjacent inductors may be configured such that adjacent inductors operate at different frequencies. In this case, the frequency of one excitation unit can be about twice the frequency of the other excitation unit. Alternatively, the frequency of one excitation unit can be greater than twice the frequency of the other excitation unit, in particular greater than 2.5 times, or advantageously greater than 3 times the frequency of the other excitation unit.

  The excitation unit may be configured to operate at an excitation frequency corresponding to a resonance frequency of the oscillation circuit. In this case, the frequency can typically be in the range 2 kHz to 50 kHz, in particular in the range 5 kHz to 25 kHz. Particularly preferably, the frequency can be exactly at 8.2 kHz or 22 kHz.

  When the excitation frequency is equal to the resonance frequency of the oscillating circuit, the excitation unit need only provide the necessary active power for heating at the resonance frequency. The reactive power that creates the electromagnetic field is provided by the oscillation circuit itself.

  In the inductor, in particular in the main winding, a pot for melting, in particular evaporating, the metal can be arranged.

  Further within the scope of the present invention is a method of inductively heating a plurality of objects using a plurality of inductors each connected to a separate excitation unit, wherein the inductors each include a feed conductor and a return conductor, A main winding portion having at least one main winding having a first winding direction. The first excitation unit is operated at a first frequency and the second excitation unit is operated at a second frequency different from the first frequency. The second frequency can be at least twice the first frequency. In particular, the first frequency can be in the range from 2 to 15 kHz, preferably from 5 to 10 kHz, particularly preferably just at 8.2 kHz. The second frequency can be in the range 15 to 50 kHz, in particular 18 to 25 kHz, preferably just 22 kHz.

  Two adjacent inductors can operate at different frequencies from each other. If the inductor is formed as an inductor according to the present invention, the inductors can be operated at different frequencies without significantly affecting each other.

  At least two inductors can be operated at alternately different frequencies.

  Inductors that are equally spaced from the connection plane can operate at the same frequency.

  Inductors having main windings which are arranged at different distances from one another with respect to the connection plane can be operated at different frequencies.

  Other features and advantages of the invention will be apparent from the following detailed description, examples of embodiments of the invention, and the claims, taken in conjunction with the drawings, which illustrate features that are important to the invention. The features shown in the drawings need not be construed as being drawn to scale, but are illustrated so that features of the invention may be more clearly seen. The various features themselves, alone or in any combination of features, may form a variation of the present invention.

  An embodiment of the present invention is shown in a schematic diagram and will be described in detail below.

It is a perspective view of one embodiment of an inductor. FIG. 2 is a plan view of the inductor shown in FIG. 1. FIG. 3 is a diagram illustrating an inductor assembly.

  FIG. 1 shows an inductor 1 including one main winding unit 2 and two reverse winding units 3 and 4. The main winding part 2 has a main winding 5 having a first winding direction. The reverse winding portions 3 and 4 have opposite winding directions. The reverse winding portions 3 and 4 are present at ends of the main winding portion 2 located on opposite sides. In the embodiment shown, the main winding 5 of the main winding 2 and the reverse windings 3, 4 have the same diameter. However, the reverse winding portions 3 and 4 may have a larger diameter than the main winding 5 of the main winding portion 2. However, in this case, it is desirable that the main winding portion 2 and the reverse winding portions 3 and 4 have a substantially columnar shape. The inductor 1 has a length 1 including the main winding part 2 and the reverse winding parts 3 and 4.

  The reverse winding portions 3, 4 have, in the embodiment shown, a substantially complete turn of one turn. However, it is also possible for the reverse winding parts 3, 4 to have only a part of one turn.

  The reverse winding portions 3 and 4 are electrically connected to the main winding portion 2 in series. This series connection is achieved by the fact that the reverse winding portions 3 and 4 are connected to the main winding portion 5 by inductor portions 6 and 7 that generate a 180 ° deflection.

  The reverse winding 4 is connected to the feed conductor 8, and the reverse winding 3 is connected to the return conductor 10 via the inductor 9. The inductor portion 9 extends substantially perpendicularly to the direction in which the return conductor 10 extends, and extends outside the main winding portion 5. The feed conductor 8 and the return conductor 10 are connected to terminals 11 and 12. Terminals 11 and 12 are used to connect to the excitation unit, but also to the coolant circuit.

  In particular, from FIG. 2, which is a plan view of FIG. 1, it can be seen that the feed conductor 8 and the return conductor 10 are arranged side by side in close proximity and extend mostly parallel to each other. Further, it can be seen that the reverse winding portions 3, 4 and the main winding portion 2 are arranged concentrically with each other. An object to be heated or a melting pot can be arranged in the internal space 13.

  An insulator 14 may be arranged between the feed conductor 8 and the return conductor 10. Furthermore, it can be seen in FIGS. 1 and 2 that the main winding part 2 is formed in a substantially columnar shape together with the reverse winding parts 3, 4. The main winding part 2 has a larger number of turns than the reverse winding parts 3 and 4. Both the inductor section 9 described above and the inductor section 15 connecting the feed conductor 8 to the reverse winding section 4 extend parallel to the longitudinal axis of the main winding section 2.

  FIG. 3 shows, in the embodiment shown, an inductor assembly 100 comprising three inductors 1, 1a, 1b. The inductors 1, 1a, 1b are formed as shown in FIG. However, the inductors 1, 1 a, 1 b may be formed such that only one reverse winding portion is provided at one end of the main winding portion 5. Further, the inductors 1, 1a, 1b may be formed differently. That is, for example, the inductor 1 may be provided so as to have two reverse winding portions at opposite ends of the main winding portion. Then, one inductor is provided so as to have a reverse winding portion only at one end of the main winding portion, and for example, the third inductor may be provided so as not to have the reverse winding portion. . Here, any variation is possible. However, it is preferred that at least one of the inductors has at least one reverse winding so as to reduce stray magnetic fields and to allow the inductors 1 to be placed side by side.

  In this case, the distance d between the longitudinal axes of the main winding portions 2 of two adjacent inductors 1 and 1a or 1a and 1b is preferably the diameter D of the main winding portion 2 of the inductors 1, 1a and 1b. It is less than five times the length 1 of the inductor 1.

  In the embodiment shown, the feed conductor 8 and the return conductor 10 of the inductors 1, 1a, 1b extend in parallel, ie not only the feed conductor 8 and the return conductor 10 of one inductor 1, but also all the feed conductors 8 and all It can also be seen that the return conductors 10 of FIG. The inductors 1, 1a, 1b are connected to excitation units 101, 102, 103, respectively. The cooling liquid is also supplied to the inductors 1, 1a, 1b by the excitation units 101 to 103. The excitation units 101 to 103 operate independently of each other and can generate alternating currents having different excitation frequencies. At that time, for example, the excitation unit 101 can generate a first excitation frequency, and the excitation unit 102 can generate a second excitation frequency. The second excitation frequency can in particular be about twice the first excitation frequency. In particular, the excitation units 101 to 103 can generate different excitation frequencies.

  The excitation units 101 to 103 are all arranged in the same connection plane e. The main winding portions 2 of the adjacent inductors 1 and 1a and 1a and 1b are arranged at mutually different intervals with respect to the connection plane e. The main winding portions 2 of the inductors 1 and 1b, which are arranged far apart from each other, are arranged at the same distance from the connection plane e.

  The excitation unit 101 has an external circuit 104 having a capacitor, the external circuit 104 being configured such that the capacitor together with the inductor 1 connected to the excitation unit 101 forms at least part of an oscillation circuit, in particular a parallel oscillation circuit. Have been. All excitation units 101 to 103 can have such an external circuit.

  As schematically shown in FIG. 3, pots 110 to 112 for melting a metal are arranged in the inductors 1, 1a, 1b.

Claims (14)

An inductor assembly (100),
At least two induction heating inductors (1, 1a, 1b);
The inductor (1, 1a, 1b) has a feed conductor (8) and a return conductor (10), and a main winding part (2), respectively. And at least one end of the main winding portion (2) has a reverse winding direction opposite to the first winding direction. The windings (3, 4) are connected, the inductors (1) are connected to the excitation units (101 to 103), respectively, and the axes of the inductors (1) are mutually main axes. The diameter (D) of the main winding part (2) or the inductor (1) according to the larger of the diameter (D) of the winding part (2) and the length (l) of the inductor (1). of which have a spacing of less than 5 times (d) the value of the length (l),
In at least one inductor (1, 1a, 1b), opposite winding portions (3, 4) having winding directions opposite to the first winding direction are provided at both ends of the main winding portion (2). It is connected,
Inductor assembly (100). In at least one inductor (1, 1a, 1b), said main winding unit (2) is characterized by having a number of turns greater than at least one of the reverse coil unit (3, 4), according to claim 1 The described inductor assembly (100). In at least one of the inductors (1, 1a, 1b), the reverse winding section (3, 4) and the main winding section (2) are arranged concentrically with each other, and both have a columnar shape. An inductor assembly (100) according to claim 1 or 2 , characterized in that: In at least one inductor (1, 1a, 1b), the main winding (2) is directly connected to the reverse winding (3, 4) by a series connection. Item 4. The inductor assembly (100) according to any one of Items 1 to 3 . In at least one inductor (1, 1a, 1b), the main winding (2) is configured in a spiral with at least one reverse winding (3, 4). Item 5. The inductor assembly (100) according to any one of Items 1 to 4 . In at least one inductor (1, 1a, 1b), at least one reverse winding part (3, 4) has a diameter at least equal to or larger than the main winding part (2). wherein, the inductor assembly according to any one of claims 1 to 5 (100). In at least one of the inductors (1, 1a, 1b), one reverse winding (4) is connected to the feed conductor (8), and the other reverse winding (3) is connected to the inductor (9) via the inductor (9). The inductor portion (9) is connected to the return conductor (10), and extends substantially perpendicular to the extending direction of the return conductor (10) and outside the main winding portion (5). wherein the inductor assembly according to any one of claims 1 to 6 (100). The terminals (11, 12) of at least two inductors (1) are arranged in one connection plane (e), and the main winding part (2) of at least two inductors (1) is characterized in that it is arranged at the same distance from the connecting plane (e), according to any one of claims 1 to 7 inductor assembly (100). The terminals (11, 12) of at least two inductors (1) are arranged in one connection plane (e), and the main winding part (2) of at least two inductors (1) is characterized in that it is arranged at a different distance from each other with respect to the plane of connection (e), according to any one of claims 1 to 8 inductor assembly (100). The excitation units (101 to 103) arranged in adjacent inductors (1, 1a, 1b) are configured such that the adjacent inductors (1, 1a, 1b) operate at mutually different frequencies. wherein the inductor assembly according to any one of claims 1 to 9 (100). The inductor assembly (100) of claim 10 , wherein the frequency of one of the excitation units is twice the frequency of the other of the excitation units. The inductor assembly (100) of claim 10 , wherein the frequency of one of the excitation units is greater than twice the frequency of the other of the excitation units. 13. The inductor assembly (100) according to claim 10 or 12 , wherein the frequency of one of the excitation units is greater than three times the frequency of the other of the excitation units. A plurality of inductors (1, 1a, 1b) which are connected to respective separate excitation units (101 to 103) having, with inductor assembly (100) of any one of claims 1 to 13 more Wherein the first excitation unit (101-103) is operated at a first frequency, and the second excitation unit (101-103) is different from the first frequency. A method for inductively heating a plurality of objects, the method comprising operating at a second frequency.

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