【発明の詳細な説明】
本発明は誘導加熱子に関し、その目的は、前記
誘導加熱子における加熱面側の効果的な断熱を可
能ならしめる前記加熱子を提供するものである。
近年、金属体、特に熱鋼片等の端部を加熱する
ために誘導加熱子（以下、単に加熱子と言う）が
積極的に用いられている。周知の通り、前記加熱
子は、例えば第１図に斜視図で示すように磁心２
と誘導線輪３とから構成されており、前記誘導線
輪３に電源４より電力を供給することによつて交
番磁束を発生せしめ加熱子１に面した被加熱材、
例えば熱鋼片５内に前記交番磁束によるうず電流
が生じ、熱鋼片５が加熱される。而して加熱子１
の加熱面側１０は極めて高温に曝されるため例え
ば第２図に示すように断熱材６を装着することが
一般的である。即ち第２図はＥ形磁心２を用いた
加熱子１を示すもので誘導線輪３はコンクリート
等を充填して構成された線輪固定材７で固定され
ている。加熱子１の加熱面側１０の前記線輪固定
材７表面にはアスベスト、セラミツクフアイバー
等の断熱材６が装着されている。ところで磁心２
の近傍には前記交番磁束が充満しているため、金
物を配置すると該金物内に大きなうず電流発熱が
生じ、金物の熱変形等の問題があることから従来
前記断熱材６の装着は、線輪固定材７に接着剤８
によつて貼着することにより行うことが普通であ
つた。つまり従来は、断熱材６を金物を利用して
固着することは前記交番磁束の貫通によるうず電
流によつて金物が発熱するため使用できないと言
う観念が当業者にとつて常識であり、而して断熱
材６は、セラミツク系接着剤等を利用して貼着さ
れていた訳である。しかしながら前記高温条件下
において接着剤８による貼着のみで、断熱材６を
長期間、安定して保持することは極めて困難であ
つて、短期間で接着剤８が剥離し、このため断熱
材６が膨出などの熱変形を生じたり、あるいは脱
落するなどのトラブルが屡々発生していた。この
ため従来は、短かい周期で断熱材６の補修を行わ
ねばならず保全費用の高騰を招いたり、適正な前
記補修を行えない結果加熱子１を損傷せしめ事故
が多く発生していた。
本発明は前記従来の問題点の抜本的な解決を計
るもので磁心、誘導線輪および線輪固定材からな
る誘導加熱子の加熱面側断熱材を、非磁性金属製
の金網で覆い、該金網を非磁性金属で構成された
締結体により前記誘導加熱子の磁心および／もし
くは線輪固定材に締結することで固定保持せし
め、前記金網の表面に不定形耐火物を被着せしめ
たことを特徴とするものである。
以下、実施例を示す図に基づき本発明を詳述す
る。
さて、第３図は本発明に基づく加熱子１の一実
施例を示す横断面図である。本実施例において
は、加熱面に接着された断熱材６を非磁性金属、
例えばステンレス鋼で構成された金網９で覆つて
保持している。断熱材６を覆つて保持する非磁性
金属の金網９は、その両側端部において非磁性金
属ボルト１１を線輪固定材７中に埋設されている
同じく非磁性金属ナツト（不図示）に螺合締結す
ることにより固着されている。尚、本実施例で
は、熱鋼片５よりの輻射熱の特に激しい下面１０
ａ断熱材６を２段に積層したが、線輪固定材７と
一層目の断熱材６ａ、および一層目の断熱材６ａ
と二層目の断熱材６ｂは前記接着剤８で接着する
ことも可能であり、適宜採用すればよい。又金網
９の表面には前記輻射熱より金網９を保護するた
めにモルタルあるいはキヤスタブル等の不定形耐
火物１３を被着せしめることが効果的である。次
に第４図は本発明の他の実施例を示す縦断面図で
ある。本実施例においては、線輪固定材７、即ち
前記コンクリート中にあらかじめ非磁性金属、例
えばステンレス鋼で形成したナツト１４が埋設さ
れている。而して、線輪固定材７の表面に断熱材
６を当接した後、その表面を前記第３図に示す実
施例と同様に金網９で覆い、しかる後、非磁性金
属で構成されたボルト１５を前記ナツト１４に螺
合し、断熱材６を締結することによつて線輪固定
材７に固着する。ボルト１５およびナツト１４か
らなる締結体１２０は加熱子１（特にこの加熱面
側１０）の大きさ、断熱材６の種類、形状、重量
等に応じて各々の大きさを設定し、かつ適宜間隔
で設ければよい。
第３図および第４図に示す実施例では、非磁性
金属ボルト１１，１２，１５と線輪固定材７中に
埋設の非磁性金属ナツト１４でもつて締結体１
２，１２０を構成しているが、非磁性金属ボルト
を、誘導加熱子の磁心に設けた螺子部に螺締して
締結してもよく、この場合の締結体は非磁性金属
ボルトのみで構成されることになる。
以上のように本発明の前記締結体は非磁性金属
で構成することによりうず電流発熱を著しく減少
できるが、本発明の効果をさらに顕著ならしめる
ために前記交番磁束の貫通方向における大きさを
できるだけ小さくすることが効果的である。例え
ば第６図は本発明の実施に当り使用するボルト１
５の一実施例を示すものであるが本発明者等の経
験では、該ボルト１５をステンレス鋼で構成し、
その鍔部直径D1を30mm以下、軸径D2を６mm以下
とすることによつてボルト１５自体の昇温を100
℃以下に抑制できることが確認できた。又金網９
も第７図に示すように線径１mmのステンレス鋼線
を、高さｈが15mm、幅ｗが30mmの亀甲型に編成し
たものを用いることによりその昇温を200℃程度
に抑えることができ、熱変形等を生じないことが
確認された。
以上のように本発明の加熱子１では断熱材６
を、非磁性金属製の金鋼で覆い、該金網を非磁性
金属で構成された締結体により誘導加熱子の磁心
および／もしくは線輪固定材に締結することで固
定保持せしめ、又必要に応じてはその大きさおよ
び形状を締結強度を有する範囲においてできるだ
け小さい最適なものとすることによつて前述のう
ず電流発熱を最小限に抑えることができるように
なつた。而して、本発明においては、断熱材６を
接着剤の使用、不使用を問わず非磁性金属締結体
で機械的に固着していることから使用できる断熱
材６の種類、大きさ、厚み等にも全く制限がなく
なり、断熱材６の寿命が大巾に向上し、加熱子１
の確実な保護が可能となつた。次に本発明の具体
的効果について説明する。
第５図に示すように巾700〜1300mm×厚250mmの
熱鋼片５（加熱前の断面平均温度は約1000℃）の
端部を上、下および側面に配設された加熱子１ａ
〜１ｃによつて加熱し、各加熱子１ａ〜１ｃに固
着された断熱材６の寿命を調査した。第１表は前
記調査結果の一例を示すもので、断熱材６の寿命
を熱鋼片５の通過処理屯数（該加熱子で加熱し、
薄鋼板に圧延した処理屯数）で表わしたものであ
る。
該第１表から明らかなように例えば加熱面側１
０が下向きとなり、その自重により断熱材６が垂
れ下がる傾向となる上側の加熱子１ａにおいて従
来700〜1000屯程度で取替を余儀なくされていた
ものが、本発明の加熱子の採用により５倍以上の
寿命延長が可能となり、特に実施例２では12000
屯以上と飛躍的にその寿命を延長できた。同様に
側面および下側の加熱子１ｂ，１ｃにおいても本
発明の加熱子１の採用により従来に比べ20倍以上
の寿命延長が可能となつた。
以上のように本発明の効果は極めて大である。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating element, and an object thereof is to provide an induction heating element that enables effective heat insulation on the heating surface side of the induction heating element. In recent years, induction heaters (hereinafter simply referred to as heaters) have been actively used to heat the ends of metal objects, particularly hot steel pieces. As is well known, the heating element has a magnetic core 2, for example as shown in a perspective view in FIG.
and a guide wire ring 3, which generates an alternating magnetic flux by supplying electric power to the guide wire ring 3 from a power source 4, and a material to be heated facing the heating element 1;
For example, an eddy current is generated in the hot steel piece 5 due to the alternating magnetic flux, and the hot steel piece 5 is heated. Therefore, heating element 1
Since the heating surface side 10 of the heating surface is exposed to extremely high temperatures, it is common to install a heat insulating material 6 as shown in FIG. 2, for example. That is, FIG. 2 shows a heating element 1 using an E-shaped magnetic core 2, and a guide wire 3 is fixed with a wire fixing material 7 filled with concrete or the like. A heat insulating material 6 such as asbestos or ceramic fiber is attached to the surface of the wire fixing material 7 on the heating surface side 10 of the heating element 1. By the way, magnetic core 2
Since the alternating magnetic flux is filled in the vicinity of the metal object, large eddy current heat generation occurs in the metal object when the metal object is placed, causing problems such as thermal deformation of the metal object. Adhesive 8 to ring fixing material 7
This was usually done by pasting it with a. In other words, it is common knowledge among those skilled in the art that conventionally, it is impossible to fix the heat insulating material 6 using metal objects because the metal objects generate heat due to the eddy current caused by the penetration of the alternating magnetic flux. In other words, the heat insulating material 6 was attached using a ceramic adhesive or the like. However, under the above-mentioned high temperature conditions, it is extremely difficult to stably hold the heat insulating material 6 for a long period of time only by pasting the heat insulating material 6 with the adhesive 8, and the adhesive 8 peels off in a short period of time. Problems such as thermal deformation such as bulging or falling off often occurred. For this reason, in the past, the heat insulating material 6 had to be repaired at short intervals, leading to a rise in maintenance costs, and as a result of not being able to carry out the repair properly, the heating element 1 was damaged and many accidents occurred. The present invention aims to fundamentally solve the above-mentioned conventional problems, and covers the heating surface side heat insulating material of an induction heater consisting of a magnetic core, a guide wire, and a wire fixing material with a wire mesh made of non-magnetic metal. A wire mesh is fixedly held by fastening it to the magnetic core and/or wire fixing material of the induction heater with a fastening body made of a non-magnetic metal, and a monolithic refractory is coated on the surface of the wire mesh. This is a characteristic feature. Hereinafter, the present invention will be explained in detail based on figures showing examples. Now, FIG. 3 is a cross-sectional view showing one embodiment of the heating element 1 based on the present invention. In this embodiment, the heat insulating material 6 bonded to the heating surface is made of non-magnetic metal.
For example, it is covered and held with a wire mesh 9 made of stainless steel. A non-magnetic metal wire mesh 9 that covers and holds the heat insulating material 6 has non-magnetic metal bolts 11 screwed into non-magnetic metal nuts (not shown) also buried in the wire ring fixing material 7 at both ends thereof. It is fixed by fastening. In this embodiment, the lower surface 10 receives particularly intense radiant heat from the heated steel piece 5.
a The insulation material 6 is laminated in two layers, but the wire fixing material 7, the first layer insulation material 6a, and the first layer insulation material 6a
It is also possible to bond the second layer of heat insulating material 6b with the adhesive 8, which may be used as appropriate. Furthermore, it is effective to cover the surface of the wire mesh 9 with a monolithic refractory material 13 such as mortar or castable in order to protect the wire mesh 9 from the radiant heat. Next, FIG. 4 is a longitudinal sectional view showing another embodiment of the present invention. In this embodiment, a nut 14 made of a non-magnetic metal such as stainless steel is embedded in the wire fixing material 7, that is, the concrete. After the heat insulating material 6 was brought into contact with the surface of the wire fixing material 7, the surface was covered with a wire mesh 9 in the same manner as in the embodiment shown in FIG. The bolt 15 is screwed into the nut 14, and the heat insulating material 6 is fastened to secure it to the wire ring fixing material 7. The fastening bodies 120 consisting of bolts 15 and nuts 14 are sized in accordance with the size of the heating element 1 (particularly the heating surface side 10), the type, shape, weight, etc. of the heat insulating material 6, and are spaced appropriately. You can set it with . In the embodiment shown in FIGS. 3 and 4, the fastening body 1 is constructed using non-magnetic metal bolts 11, 12, 15 and a non-magnetic metal nut 14 embedded in the wire ring fixing material 7.
2,120, but a non-magnetic metal bolt may be screwed into a threaded portion provided in the magnetic core of the induction heater, and the fastening body in this case is composed only of non-magnetic metal bolts. will be done. As described above, by constructing the fastening body of the present invention from non-magnetic metal, eddy current heat generation can be significantly reduced.However, in order to make the effect of the present invention even more remarkable, the size of the alternating magnetic flux in the penetrating direction is reduced as much as possible. It is effective to make it smaller. For example, Fig. 6 shows the bolt 1 used in carrying out the present invention.
However, in the experience of the present inventors, the bolt 15 is made of stainless steel,
By setting the flange diameter D 1 to 30 mm or less and the shaft diameter D 2 to 6 mm or less, the temperature rise of the bolt 15 itself can be reduced by 100 mm.
It was confirmed that the temperature could be suppressed to below ℃. Also wire mesh 9
As shown in Figure 7, the temperature rise can be suppressed to about 200°C by using stainless steel wire with a wire diameter of 1 mm arranged in a hexagonal shape with a height h of 15 mm and a width w of 30 mm. It was confirmed that no thermal deformation occurred. As described above, in the heating element 1 of the present invention, the heat insulating material 6
is covered with non-magnetic metal steel, and fixedly held by fastening the wire mesh to the magnetic core and/or coil fixing material of the induction heater with a fastener made of non-magnetic metal, and as necessary. It has become possible to minimize the above-mentioned eddy current heat generation by optimizing its size and shape to be as small as possible within the range of fastening strength. Therefore, in the present invention, since the heat insulating material 6 is mechanically fixed with a non-magnetic metal fastener, regardless of whether adhesive is used or not, the type, size, and thickness of the heat insulating material 6 that can be used are limited. etc., the life of the heat insulating material 6 is greatly improved, and the heating element 1
It has become possible to securely protect the Next, specific effects of the present invention will be explained. As shown in Fig. 5, heating elements 1a are attached to the ends of a heated steel piece 5 (width 700 to 1300 mm x thickness 250 mm (average cross-sectional temperature before heating is approximately 1000°C)) on the top, bottom, and sides.
1c, and the life of the heat insulating material 6 fixed to each heating element 1a to 1c was investigated. Table 1 shows an example of the above survey results, and shows the life of the heat insulating material 6 by the number of tons of heated steel slab 5 (heated by the heating element,
It is expressed in terms of the number of tons rolled into thin steel sheets. As is clear from Table 1, for example, heating surface side 1
0 points downward and the insulation material 6 tends to sag due to its own weight. Conventionally, the heating element 1a on the upper side had to be replaced after about 700 to 1000 tons, but with the adoption of the heating element of the present invention, the heating element 6 can be replaced more than 5 times more. In particular, in Example 2, the lifespan of 12,000
We were able to dramatically extend its lifespan beyond that of the tun. Similarly, by adopting the heating element 1 of the present invention for the side and lower heating elements 1b and 1c, it has become possible to extend the lifespan by more than 20 times compared to the conventional one. As described above, the effects of the present invention are extremely large. 【table】
【図面の簡単な説明】[Brief explanation of the drawing]
第１図は、一般的な加熱子を示す斜視図、第２
図は従来の加熱子の一実施例を示す縦断面図、第
３図乃至第７図は本発明の実施例を示すもので第
３図は横断面図、第４図は縦断面図、第５図は加
熱子の配設状況を示す断面図、第６図はボルトの
構造図、第７図は金網の構造図である。
１……誘導加熱子、２……磁心、３……誘導線
輪、４……電源、５……熱鋼片、６……断熱材、
７……コンクリート、８……接着剤、９……金
網、１０……誘導加熱子の加熱面側、１１，１５
……ボルト、１２……締結体、１３……不定形耐
火物、１４……ナツト、１６……螺子部。
Figure 1 is a perspective view showing a general heating element, Figure 2 is a perspective view showing a general heating element;
The figure is a longitudinal cross-sectional view showing an embodiment of a conventional heating element, and Fig. 3 to Fig. 7 are cross-sectional views showing an embodiment of the present invention. FIG. 5 is a sectional view showing the arrangement of the heating element, FIG. 6 is a structural diagram of the bolt, and FIG. 7 is a structural diagram of the wire mesh. 1...Induction heating element, 2...Magnetic core, 3...Induction wire ring, 4...Power source, 5...Heating steel piece, 6...Insulating material,
7... Concrete, 8... Adhesive, 9... Wire mesh, 10... Heating surface side of induction heater, 11, 15
... Bolt, 12 ... Fastening body, 13 ... Monolithic refractory, 14 ... Nut, 16 ... Thread part.