JP2021025679A - Induction furnace - Google Patents
Induction furnace Download PDFInfo
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- JP2021025679A JP2021025679A JP2019142468A JP2019142468A JP2021025679A JP 2021025679 A JP2021025679 A JP 2021025679A JP 2019142468 A JP2019142468 A JP 2019142468A JP 2019142468 A JP2019142468 A JP 2019142468A JP 2021025679 A JP2021025679 A JP 2021025679A
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- coil
- conductive layer
- induction furnace
- conductive
- joint iron
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- 230000006698 induction Effects 0.000 title claims abstract description 56
- 239000000463 material Substances 0.000 claims abstract description 31
- 230000002093 peripheral effect Effects 0.000 claims abstract description 15
- 239000011248 coating agent Substances 0.000 claims abstract description 14
- 238000000576 coating method Methods 0.000 claims abstract description 14
- 239000011347 resin Substances 0.000 claims abstract description 7
- 229920005989 resin Polymers 0.000 claims abstract description 7
- 239000000853 adhesive Substances 0.000 claims abstract description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 78
- 229910052742 iron Inorganic materials 0.000 claims description 39
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims description 5
- 230000001070 adhesive effect Effects 0.000 claims description 4
- 238000009413 insulation Methods 0.000 abstract description 5
- 230000005684 electric field Effects 0.000 description 23
- 239000004020 conductor Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 5
- 239000012212 insulator Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000005674 electromagnetic induction Effects 0.000 description 2
- 230000020169 heat generation Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 235000000396 iron Nutrition 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B14/00—Crucible or pot furnaces
- F27B14/06—Crucible or pot furnaces heated electrically, e.g. induction crucible furnaces with or without any other source of heat
- F27B14/061—Induction furnaces
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/36—Coil arrangements
- H05B6/365—Coil arrangements using supplementary conductive or ferromagnetic pieces
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/02—Induction heating
- H05B6/36—Coil arrangements
- H05B6/367—Coil arrangements for melting furnaces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Crucibles And Fluidized-Bed Furnaces (AREA)
- Furnace Details (AREA)
- General Induction Heating (AREA)
Abstract
Description
本発明は、るつぼで被加熱材を加熱する誘導炉に関する。 The present invention relates to an induction furnace that heats a material to be heated in a crucible.
るつぼの外周にコイルが巻回された誘導炉が知られている。コイルには高周波で高電圧の交流が印加されて電磁誘導を発生させ、るつぼに収容された被加熱材の内部に渦電流を生じさせ効率良く熔解させることができる。被加熱材は例えば金属溶融である。るつぼは金属溶融以外への熱伝導を抑制している。コイルは絶縁被覆や絶縁板などの絶縁物で絶縁されている。 An induction furnace in which a coil is wound around the outer circumference of a crucible is known. A high-frequency, high-voltage alternating current is applied to the coil to generate electromagnetic induction, and an eddy current is generated inside the material to be heated housed in the crucible, which can be efficiently melted. The material to be heated is, for example, metal melt. The crucible suppresses heat conduction other than metal melting. The coil is insulated with an insulating coating or an insulating material such as an insulating plate.
このような誘導炉としては、例えば特許文献１に記載のものが挙げられる。特許文献１に記載の誘導炉は、真空容器中で使用される小型のものである。一方、大型の誘導炉の場合にはコイルを外周側から保持するために継鉄が用いられる。継鉄は接地されている。 Examples of such an induction furnace include those described in Patent Document 1. The induction furnace described in Patent Document 1 is a small one used in a vacuum vessel. On the other hand, in the case of a large induction furnace, a joint iron is used to hold the coil from the outer peripheral side. The joint iron is grounded.
誘導炉は一層の大容量化および高効率化が望まれている。高効率化を実現するためには、コイルの印加電圧を上昇させてその分電流を低下させればコイルの発熱を抑制させることができて好適である。 It is desired that the induction furnace has a larger capacity and higher efficiency. In order to achieve high efficiency, it is preferable to increase the applied voltage of the coil and decrease the current by that amount because the heat generation of the coil can be suppressed.
コイルに印加できる電圧はコイルの絶縁物の性能と厚みとによってほぼ決まる。しかしながら従来の構成では、良質の絶縁物を相当に厚く形成しても、絶縁物の端部や継鉄の端部に電界集中が発生している。このため、コイルの印加電圧が過大であると継鉄とコイルとの間で部分放電が発生して絶縁物が劣化し全路破壊が発生する懸念がある。本願発明者の実験によれば１０ｋＶ以上の電圧をコイルに印加するとこのような放電が発生する可能性がある。したがって、従来の誘導炉ではコイル印加電圧が概ね５ｋＶ程度に制限されており、一層の高圧化が望まれている。 The voltage that can be applied to the coil is largely determined by the performance and thickness of the coil insulation. However, in the conventional configuration, even if a good quality insulator is formed to be considerably thick, electric field concentration is generated at the end of the insulator and the end of the joint iron. Therefore, if the applied voltage of the coil is excessive, there is a concern that a partial discharge may occur between the joint iron and the coil, the insulator may deteriorate, and the entire road may be destroyed. According to the experiment of the inventor of the present application, such a discharge may occur when a voltage of 10 kV or more is applied to the coil. Therefore, in the conventional induction furnace, the coil applied voltage is limited to about 5 kV, and further increase in pressure is desired.
本発明は、上記の課題に鑑みてなされたものであって、コイルに対する印加電圧を一層上昇させることのできる誘導炉を提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide an induction furnace capable of further increasing the voltage applied to the coil.
上述した課題を解決し、目的を達成するために、本発明にかかる誘導炉は、被加熱材を収納するるつぼと、前記るつぼの外周に巻回され、絶縁被覆を有するコイルと、前記コイルの外周面を覆う導電層と、前記導電層を介して前記コイルを外周側から保持する継鉄と、を備え、前記導電層および前記継鉄は接地されていることを特徴とする。 In order to solve the above-mentioned problems and achieve the object, the induction furnace according to the present invention includes a crucible for accommodating a material to be heated, a coil wound around the outer circumference of the crucible and having an insulating coating, and the coil. A conductive layer that covers the outer peripheral surface and a joint iron that holds the coil from the outer peripheral side via the conductive layer are provided, and the conductive layer and the joint iron are grounded.
前記導電層は導電性樹脂または導電性接着剤であり、前記コイルの絶縁被覆と密着していてもよい。 The conductive layer is a conductive resin or a conductive adhesive, and may be in close contact with the insulating coating of the coil.
前記導電層と前記コイルとの間には絶縁シートが設けられていてもよい。 An insulating sheet may be provided between the conductive layer and the coil.
前記導電層と前記継鉄の間に導電性の緩衝材を備え、前記導電層は、前記緩衝材および前記継鉄を介して接地されていてもよい。 A conductive cushioning material may be provided between the conductive layer and the joint iron, and the conductive layer may be grounded via the cushioning material and the joint iron.
前記コイルの導線は断面が角型であってもよい。 The lead wire of the coil may have a square cross section.
本発明にかかる誘導炉は、コイルの絶縁被覆に加わる電界を均一化させて部分放電の発生を抑制することができる。これによりコイルに対する印加電圧を一層上昇させることができる。 The induction furnace according to the present invention can equalize the electric field applied to the insulating coating of the coil and suppress the occurrence of partial discharge. As a result, the voltage applied to the coil can be further increased.
以下に、本発明にかかる誘導炉の実施形態を図面に基づいて詳細に説明する。なお、この実施形態によりこの発明が限定されるものではない。 Hereinafter, embodiments of the induction furnace according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.
図１は、本発明の実施形態である誘導炉１０を示す側面模式断面図であり、図２は、誘導炉１０の模式平面図である。 FIG. 1 is a schematic side sectional view showing the induction furnace 10 according to the embodiment of the present invention, and FIG. 2 is a schematic plan view of the induction furnace 10.
図１および図２に示すように、誘導炉１０は、被加熱材１２を収納するるつぼ１４と、るつぼ１４の外周に巻回された誘導加熱用のコイル１６と、コイル１６の外周を覆う導電層１８と、導電層１８の外周を覆う緩衝材２０と、導電層１８および緩衝材２０を介してコイル１６を外周側から保持する継鉄２２とを備える。るつぼ１４、コイル１６、導電層１８、緩衝材２０および継鉄２２は下部キャスタブル２４の上に設置されている。誘導炉１０は全体が導電性の筐体２６で覆われており、該筐体２６はアース線２８で接地されている。継鉄２２は筐体２６と接しており、該筐体２６を介して接地されている。また、後述するように、導電層１８は緩衝材２０および継鉄２２を介して接地されている。筐体２６は破線で示している。 As shown in FIGS. 1 and 2, the induction furnace 10 includes a pot 14 for accommodating the material to be heated 12, a coil 16 for induction heating wound around the outer circumference of the pot 14, and a conductor covering the outer circumference of the coil 16. A layer 18, a cushioning material 20 that covers the outer periphery of the conductive layer 18, and a joint iron 22 that holds the coil 16 from the outer peripheral side via the conductive layer 18 and the cushioning material 20 are provided. The crucible 14, the coil 16, the conductive layer 18, the cushioning material 20, and the joint iron 22 are installed on the lower castable 24. The induction furnace 10 is entirely covered with a conductive housing 26, and the housing 26 is grounded by a ground wire 28. The joint iron 22 is in contact with the housing 26 and is grounded via the housing 26. Further, as will be described later, the conductive layer 18 is grounded via the cushioning material 20 and the joint iron 22. The housing 26 is shown by a broken line.
誘導炉１０は大型であり、コイル１６を保持するために継鉄２２が設けられている。ただし、誘導炉１０の構造を小型のものに適用してもよい。誘導炉１０は全体を傾斜させることにより、るつぼ１４内の被加熱材１２の取出しが可能である。誘導炉１０は空気中に設置される。誘導炉１０は、交番磁界中に溶解される被加熱材１２を収容し、電磁誘導によって被加熱材に渦電流を流して誘導加熱し熔解し金属溶湯を得る。 The induction furnace 10 is large in size, and a joint iron 22 is provided to hold the coil 16. However, the structure of the induction furnace 10 may be applied to a small one. By inclining the entire induction furnace 10, the material 12 to be heated in the crucible 14 can be taken out. The induction furnace 10 is installed in the air. The induction furnace 10 accommodates a material to be heated 12 that is melted in an alternating magnetic field, and an eddy current is passed through the material to be heated by electromagnetic induction to induce heating and melt it to obtain a molten metal.
導電層１８はコイル１６の下端部から上端部まで外側の全周を覆う。導電層１８は、例えばカーボンなどを含む導電性樹脂または導電性接着剤であり、コイル１６の導線３０（図３参照）とほぼ隙間なく密着している。また、導電性樹脂として導電性シリコーンゴムなどの軟質導電性樹脂を使用することでコイル１６の動き（始動時の振動など）に追従することができる。導電層１８はコイル１６の外側に設けられており、内側には設けられていない。コイル１６の内側では放電がほとんど発生しないためである。 The conductive layer 18 covers the entire outer circumference from the lower end to the upper end of the coil 16. The conductive layer 18 is, for example, a conductive resin or a conductive adhesive containing carbon or the like, and is in close contact with the conducting wire 30 (see FIG. 3) of the coil 16 with almost no gap. Further, by using a soft conductive resin such as conductive silicone rubber as the conductive resin, it is possible to follow the movement of the coil 16 (vibration at the time of starting, etc.). The conductive layer 18 is provided on the outside of the coil 16 and not on the inside. This is because almost no discharge is generated inside the coil 16.
導電層１８によれば、コイル１６の絶縁被覆３０ｂ（図３参照）に加わる電界を均一化し、部分放電の発生を抑制することができる。これにより、誘導炉１０の高耐圧化・高寿命化を実現することができる。 According to the conductive layer 18, the electric field applied to the insulating coating 30b (see FIG. 3) of the coil 16 can be made uniform, and the occurrence of partial discharge can be suppressed. As a result, it is possible to realize a high pressure resistance and a long life of the induction furnace 10.
緩衝材２０はコイル１６から継鉄２２に伝わる振動を吸収および緩和する。緩衝材２０はカーボンなどを含んで導電性を有している。緩衝材２０は、導電層１８と継鉄２２の間に設けられていて導電層１８と継鉄２２とを導通する。したがって、導電層１８は緩衝材２０および継鉄２２を介して接地される。 The cushioning material 20 absorbs and alleviates the vibration transmitted from the coil 16 to the joint iron 22. The cushioning material 20 contains carbon and the like and has conductivity. The cushioning material 20 is provided between the conductive layer 18 and the joint iron 22, and conducts the conductive layer 18 and the joint iron 22. Therefore, the conductive layer 18 is grounded via the cushioning material 20 and the joint iron 22.
継鉄２２は、略角柱形状であって緩衝材２０の周りに複数設けられる。継鉄２２はるつぼ１４の膨張力に対してコイル１６を側方から支える機能を有する。継鉄２２は筐体２６に溶接されており導通がある。 A plurality of joint irons 22 have a substantially prismatic shape and are provided around the cushioning material 20. The joint iron 22 has a function of supporting the coil 16 from the side against the expansion force of the crucible 14. The joint iron 22 is welded to the housing 26 and has continuity.
図３は、コイル１６およびその周辺部の一部拡大断面図である。図３に示すように、コイル１６は、るつぼ１４の外周を導線３０が螺旋状に巻回して形成されている。導線３０は、導体部３０ａと、該導体部３０ａの外側を覆う絶縁被覆３０ｂとを有する。導体部３０ａの内部には冷媒路３０ｃが形成されている。導線３０は断面が角型（平角型、真四角型を含む）であって、隣接するターン同士の面が接するように密に巻回されている。したがって、導線３０の隣接するターン同士の隙間がほとんどないため導体部３０ａの占める面積割合が大きく、抵抗が小さくなり発熱が少ない。また、その分電流値を大きくすることができるため、所定出力あたりのサイズを小型化することができる。さらに、分布容量が減少しコイル１６全体の浮遊容量が小さくなるという利点がある。 FIG. 3 is a partially enlarged cross-sectional view of the coil 16 and its peripheral portion. As shown in FIG. 3, the coil 16 is formed by spirally winding a lead wire 30 around the outer circumference of the crucible 14. The conductor portion 30 has a conductor portion 30a and an insulating coating 30b that covers the outside of the conductor portion 30a. A refrigerant passage 30c is formed inside the conductor portion 30a. The lead wire 30 has a square cross section (including a flat square type and a square shape), and is tightly wound so that the surfaces of adjacent turns are in contact with each other. Therefore, since there is almost no gap between the adjacent turns of the conducting wire 30, the area ratio occupied by the conductor portion 30a is large, the resistance is small, and the heat generation is small. Further, since the current value can be increased by that amount, the size per predetermined output can be reduced. Further, there is an advantage that the distributed capacitance is reduced and the stray capacitance of the entire coil 16 is reduced.
さらにまた、導線３０が角型であることにより、コイル１６の内周面および外周面がほとんど凹凸のない滑らかな曲面となる。特に、外周面に凹凸がほとんどないことにより、電界集中を抑制し、継鉄２２との間で放電が発生することを抑制できる。 Furthermore, since the lead wire 30 is square, the inner peripheral surface and the outer peripheral surface of the coil 16 have a smooth curved surface with almost no unevenness. In particular, since there is almost no unevenness on the outer peripheral surface, it is possible to suppress electric field concentration and suppress the generation of electric discharge with the joint iron 22.
図３に示すように、導電層１８はコイル１６の絶縁被覆３０ｂと密着しており、汚損防止および電界集中を抑制することができる。また、導電層１８は導電性樹脂または導電性接着剤であることから絶縁被覆と密着させることが容易であり、また鉄板と較べて軽量である。 As shown in FIG. 3, the conductive layer 18 is in close contact with the insulating coating 30b of the coil 16 and can prevent fouling and suppress electric field concentration. Further, since the conductive layer 18 is a conductive resin or a conductive adhesive, it can be easily brought into close contact with the insulating coating, and is lighter than an iron plate.
また、緩衝材２０は内周面が導電層１８に接し、外周面が継鉄２２に接している。したがって、導電層１８は緩衝材２０および継鉄２２を介して接地されており、導電層１８の専用の接地手段が不要である。ただし、導電層１８は緩衝材２０および継鉄２２とは別に接地されていてもよい。 Further, the inner peripheral surface of the cushioning material 20 is in contact with the conductive layer 18, and the outer peripheral surface is in contact with the joint iron 22. Therefore, the conductive layer 18 is grounded via the cushioning material 20 and the joint iron 22, and a dedicated grounding means for the conductive layer 18 is unnecessary. However, the conductive layer 18 may be grounded separately from the cushioning material 20 and the joint iron 22.
図４は、誘導炉における継鉄２２の周辺で発生する電界強度の解析結果を示す図であり、（ａ）は比較例１にかかる誘導炉５００Ａにおける電界強度の解析結果を示す図であり、（ｂ）は比較例２にかかる誘導炉５００Ｂにおける電界強度の解析結果を示す図であり、（ｃ）は誘導炉１０Ａにおける電界の解析結果を示す図である。誘導炉１０Ａは上記の実施形態にかかる誘導炉１０と類似の構成である。図４における濃淡地の部分は電界強度を示し、濃淡地が濃い箇所ほど電界強度が強く、薄い箇所ほど電界強度が弱い。コイル１６に高周波・高電圧の交流を印加し、継鉄２２は接地されている条件とし、コンピュータにより解析した。 FIG. 4 is a diagram showing the analysis result of the electric field strength generated around the joint iron 22 in the induction furnace, and FIG. 4A is a diagram showing the analysis result of the electric field strength in the induction furnace 500A according to Comparative Example 1. (B) is a diagram showing the analysis result of the electric field strength in the induction furnace 500B according to Comparative Example 2, and (c) is a diagram showing the analysis result of the electric field in the induction furnace 10A. The induction furnace 10A has a configuration similar to that of the induction furnace 10 according to the above embodiment. The shaded area in FIG. 4 shows the electric field strength. The darker the shaded area, the stronger the electric field strength, and the lighter the shaded area, the weaker the electric field strength. High-frequency and high-voltage alternating current was applied to the coil 16, and the joint iron 22 was grounded, and the analysis was performed by a computer.
図４（ａ）に示すように、誘導炉５００Ａは継鉄２２とコイル１６との間に円弧状の絶縁シート３２を設けたものである。従来、継鉄２２の周方向端部２２ａは電界が集中しやすいと考えられている箇所である。 As shown in FIG. 4A, the induction furnace 500A is provided with an arc-shaped insulating sheet 32 between the joint iron 22 and the coil 16. Conventionally, the circumferential end 22a of the joint iron 22 is a place where it is considered that an electric field is likely to be concentrated.
絶縁シート３２はコイル１６の外周に沿って継鉄２２との間に設けられている。絶縁シート３２は継鉄２２よりも周方向にやや長くなっている。コイル１６は表面に防塵ガラステープが設けられている条件とした。絶縁シート３２はマイカシートの条件にした。この誘導炉５００Ａにおいては、周方向端部２２ａの箇所はコイル１６に対して絶縁シート３２によって遮られている。しかしながら解析の結果からは、絶縁シート３２の周方向端部３２ａとコイル１６との隙間部分には強い電界集中が生じており、継鉄２２の周方向端部２２ａの周辺にもやや高い電界集中が生じていることが分かる。このような強い電界が生じている箇所では放電が発生する懸念がある。 The insulating sheet 32 is provided between the coil 16 and the joint iron 22 along the outer circumference of the coil 16. The insulating sheet 32 is slightly longer in the circumferential direction than the joint iron 22. The coil 16 was provided with a dustproof glass tape on the surface. The insulating sheet 32 was set to the condition of a mica sheet. In this induction furnace 500A, the portion of the circumferential end 22a is shielded from the coil 16 by the insulating sheet 32. However, from the results of the analysis, a strong electric field concentration is generated in the gap between the circumferential end 32a of the insulating sheet 32 and the coil 16, and a slightly high electric field concentration is also generated around the circumferential end 22a of the joint iron 22. It can be seen that is occurring. There is a concern that an electric discharge may occur in a place where such a strong electric field is generated.
図４（ｂ）に示すように、誘導炉５００Ｂはコイル１６の全外周を絶縁シート３２で覆ったものである。絶縁シート３２の材質および厚みは誘導炉５００Ａの場合と同様である。解析の結果、誘導炉５００Ｂの場合、誘導炉５００Ａと同様の２か所に電界集中が生じていることが分かる。この場合も放電が発生する可能性がある。 As shown in FIG. 4B, the induction furnace 500B covers the entire outer circumference of the coil 16 with an insulating sheet 32. The material and thickness of the insulating sheet 32 are the same as in the case of the induction furnace 500A. As a result of the analysis, in the case of the induction furnace 500B, it can be seen that the electric field concentration occurs at two places similar to the induction furnace 500A. In this case as well, electric discharge may occur.
図４（ｃ）に示すように、誘導炉１０Ａは導電層１８ａを有する。導電層１８ａは上記の導電層１８に対応する。ここでは、解析の都合により導電層１８ａは鉄板とし、該導電層１８ａが継鉄２２と接触することでコイル１６の全周を覆う形となっている。また、コイル１６の変形を吸収するために該コイル１６との間に隙間を設けている。さらに、比較例にかかる誘導炉５００Ｂと同じ条件とするために導電層１８ａとコイル１６との間には絶縁シート３２を設けている。解析の結果、誘導炉１０Ａでは電界集中は認められず、放電が発生する可能性は極めて低いことが分かる。また、この解析の結果から上記の誘導炉１０においても放電が発生する可能性は極めて低いと考えることができる。 As shown in FIG. 4C, the induction furnace 10A has a conductive layer 18a. The conductive layer 18a corresponds to the above-mentioned conductive layer 18. Here, for convenience of analysis, the conductive layer 18a is an iron plate, and the conductive layer 18a is in contact with the joint iron 22 to cover the entire circumference of the coil 16. Further, a gap is provided between the coil 16 and the coil 16 in order to absorb the deformation of the coil 16. Further, an insulating sheet 32 is provided between the conductive layer 18a and the coil 16 in order to satisfy the same conditions as the induction furnace 500B according to the comparative example. As a result of the analysis, it can be seen that the electric field concentration is not observed in the induction furnace 10A, and the possibility of electric discharge is extremely low. Further, from the result of this analysis, it can be considered that the possibility of electric discharge occurring in the above induction furnace 10 is extremely low.
上述したように、本実施の形態にかかる誘導炉１０，１０Ａでは、コイル１６の絶縁被覆３０ｂに加わる電界を均一化させて部分放電の発生を抑制することができる。これによりコイル１６に対する印加電圧を一層上昇させ、誘導炉１０のエネルギー効率を一層上昇させることができる。本願発明者の解析によれば、誘導炉１０、１０Ａは、例えば１５ｋＶでの使用が可能である。 As described above, in the induction furnaces 10 and 10A according to the present embodiment, the electric field applied to the insulating coating 30b of the coil 16 can be made uniform to suppress the occurrence of partial discharge. As a result, the voltage applied to the coil 16 can be further increased, and the energy efficiency of the induction furnace 10 can be further increased. According to the analysis of the inventor of the present application, the induction furnaces 10 and 10A can be used at, for example, 15 kV.
本発明は、上記した実施形態に限定されるものではなく、本発明の主旨を逸脱しない範囲で自由に変更できることは勿論である。 The present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be freely modified without departing from the gist of the present invention.
１０，１０Ａ 誘導炉
１２ 被加熱材
１４ るつぼ
１６ コイル
１８，１８ａ 導電層
２０ 緩衝材
２２ 継鉄
２４ 下部キャスタブル
２６ 筐体
２８ アース線
３０ 導線
３０ａ 導体部
３０ｂ 絶縁被覆
３２ 絶縁シート
10,10A Induction furnace 12 Heated material 14 Crucible 16 Coil 18, 18a Conductive layer 20 Cushioning material 22 Joint iron 24 Lower castable 26 Housing 28 Ground wire 30 Conductor wire 30a Conductor 30b Insulation coating 32 Insulation sheet
Claims (5)
前記るつぼの外周に巻回され、絶縁被覆を有するコイルと、
前記コイルの外周面を覆う導電層と、
前記導電層を介して前記コイルを外周側から保持する継鉄と、
を備え、
前記導電層および前記継鉄は接地されていることを特徴とする誘導炉。 A crucible for storing the material to be heated and
A coil wound around the outer circumference of the crucible and having an insulating coating,
A conductive layer covering the outer peripheral surface of the coil and
A joint iron that holds the coil from the outer peripheral side via the conductive layer,
With
An induction furnace characterized in that the conductive layer and the joint iron are grounded.
前記導電層は、前記緩衝材および前記継鉄を介して接地されていることを特徴とする請求項１〜３のいずれか１項に記載の誘導炉。 A conductive cushioning material is provided between the conductive layer and the joint iron.
The induction furnace according to any one of claims 1 to 3, wherein the conductive layer is grounded via the cushioning material and the joint iron.
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| CN112304087A (en) | 2021-02-02 |
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