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EP0081776A2 - Coil coating or coil embedding of refractory concrete, and method of manufacturing it - Google Patents

Coil coating or coil embedding of refractory concrete, and method of manufacturing it Download PDF

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Publication number
EP0081776A2
EP0081776A2 EP82111239A EP82111239A EP0081776A2 EP 0081776 A2 EP0081776 A2 EP 0081776A2 EP 82111239 A EP82111239 A EP 82111239A EP 82111239 A EP82111239 A EP 82111239A EP 0081776 A2 EP0081776 A2 EP 0081776A2
Authority
EP
European Patent Office
Prior art keywords
coil
refractory concrete
glass fibers
embedding
lining
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP82111239A
Other languages
German (de)
French (fr)
Other versions
EP0081776A3 (en
Inventor
Manfred Ing. Grad. Mertens
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Germany
Original Assignee
Brown Boveri und Cie AG Germany
BBC Brown Boveri AG Germany
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Brown Boveri und Cie AG Germany, BBC Brown Boveri AG Germany filed Critical Brown Boveri und Cie AG Germany
Publication of EP0081776A2 publication Critical patent/EP0081776A2/en
Publication of EP0081776A3 publication Critical patent/EP0081776A3/en
Withdrawn legal-status Critical Current

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Classifications

    • 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

Definitions

  • the invention relates to a coil lining or coil embedding made of refractory concrete, in particular for induction coils.
  • Induction coils for inductive heaters are either only lined with refractory concrete on the inside or are completely cast in.
  • the refractory concrete has a certain resistance to temperature changes and tends to grow, i.e. Over time, cracks appear in the lining, mostly in the radial direction. Through these cracks, scale of the workpiece to be heated or other contamination can migrate up to the coil winding and, in the worst case, lead to a short turn.
  • the grain size must be chosen depending on the winding distance of the coil winding, because is the grain size larger than the distance between the turns, the concrete cannot penetrate between the turns and ensure good anchoring with the turns.
  • the object of the invention is to provide a coil lining or coil embedding made of refractory concrete, in particular for induction coils, the refractory concrete of which has a high thermal shock resistance even with a fine grain size, so that the crack sensitivity, especially at operating temperatures up to 1200 0 C, is greatly reduced and the growth of the refractory concrete during operation is kept to a minimum or even avoided entirely.
  • the refractory concrete contains approximately evenly distributed, alkali-resistant glass fibers.
  • a corresponding glass composition for the glass fibers is bsw. from DE-OS 20 37 910 become known.
  • the length of the glass fibers is preferably between 12 and 25 mm.
  • Their volume fraction in refractory concrete is preferably between 2% and 6%.
  • Two methods are specified for producing a coil lining or coil embedding from refractory concrete.
  • a second method according to the invention is characterized in that the refractory concrete, which is produced in a manner known per se, is pressed out of an annular nozzle aligned with the coil, the glass fibers cut to length in the spray head being admixed to it at the same time.
  • This method has the advantage that the distribution of the glass fibers in the concrete is more uniform than that in the first-mentioned method and that a higher volume fraction of glass fibers in refractory concrete can be achieved.
  • a single-layer insulated induction coil winding 1 can be seen, which is embedded in refractory concrete 2 on all sides, with the exception of supply and discharge lines, not shown.
  • the refractory concrete 2 is shown in a cuboid shape (however, it can also have a different external shape, for example a cylindrical shape) and has a central bore 3 which runs coaxially with the inductor winding 1.
  • a cylindrical, metallic workpiece 4 is arranged within the bore 3. The outside diameter of the workpiece 4 is significantly smaller than the inside diameter of the bore 3, so that the workpiece 4 can be moved axially without touching the refractory concrete 2 can.
  • the refractory concrete 2 contains a mixture of glass fibers, which considerably increases its resistance to temperature changes.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

The invention relates to a coil coating or coil embedding of refractory concrete, especially for induction coils, the refractory concrete of which has a low crack sensitivity and a low tendency to grow. For this purpose, approximately evenly distributed, alkali-resistant glass-fibres are contained in the refractory concrete. The length of the glass-fibres is preferably between 12 and 25 mm. Their volume content in the refractory concrete is preferably between 2% and 6%. <IMAGE>

Description

Die Erfindung betrifft eine Spulenauskleidung bzw. Spuleneinbettung aus Feuerfestbeton, insbes. für Induktionsspulen.The invention relates to a coil lining or coil embedding made of refractory concrete, in particular for induction coils.

Induktionsspulen für induktive Erwärmer werden entweder nur innen mit einem Feuerfestbeton ausgekleidet oder ganz eingegossen. Der Feuerfestbeton hat je nach Zusammensetzung und Körnung eine bestimmte Temperaturwechselbeständigkeit und neigt zum Wachsen, d.h. im Laufe der Zeit entstehen in der Ausmauerung Risse, meist in radialer Richtung. Durch diese Risse kann nun Zunder des zu erwärmenden Werkstückes oder sonstige Verunreinigung bis zur Spulenwicklung wandern und schlimmstenfalls zum Windungsschluß führen.Induction coils for inductive heaters are either only lined with refractory concrete on the inside or are completely cast in. Depending on the composition and grain size, the refractory concrete has a certain resistance to temperature changes and tends to grow, i.e. Over time, cracks appear in the lining, mostly in the radial direction. Through these cracks, scale of the workpiece to be heated or other contamination can migrate up to the coil winding and, in the worst case, lead to a short turn.

Je grober die Körnung des Feuerfestbetons ist, desto besser ist seine Temperaturwechselbeständigkeit. Die Korngröße muß aber abhängig vom Windungsabstand der Spulenwicklung gewählt werden, denn ist die Korngröße größer als der Windungsabstand, kann der Beton nicht zwischen die Windungen eindringen und eine gute Verankerung mit den Windungen herbeiführen.The coarser the grain of the refractory concrete, the better its resistance to temperature changes. The grain size must be chosen depending on the winding distance of the coil winding, because is the grain size larger than the distance between the turns, the concrete cannot penetrate between the turns and ensure good anchoring with the turns.

Aufgabe der Erfindung ist es, eine Spulenauskleidung bzw. Spuleneinbettung aus Feuerfestbeton, insbes. für Induktionsspulen, anzugeben, deren Feuerfestbeton auch bei einer feinen Körnung eine hohe Temperaturwechselbeständigkeit aufweist, so daß die Rißempfindlichkeit, insbes. bei Betriebstemperaturen bis 12000 C, stark herabgesetzt wird und das Wachsen des Feuerfestbetons während des Betriebs auf ein Minimum beschränkt oder sogar ganz vermieden wird.The object of the invention is to provide a coil lining or coil embedding made of refractory concrete, in particular for induction coils, the refractory concrete of which has a high thermal shock resistance even with a fine grain size, so that the crack sensitivity, especially at operating temperatures up to 1200 0 C, is greatly reduced and the growth of the refractory concrete during operation is kept to a minimum or even avoided entirely.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß in dem Feuerfestbeton annähernd gleichmäßig verteilte, alkalibeständige Glasfasern enthalten sind. Eine entsprechende Glaszusammensetzung für die Glasfasern ist bsw. aus der DE-OS 20 37 910 bekanntgeworden.This object is achieved in that the refractory concrete contains approximately evenly distributed, alkali-resistant glass fibers. A corresponding glass composition for the glass fibers is bsw. from DE-OS 20 37 910 become known.

Die Länge der Glasfasern beträgt vorzugsweise zwischen 12 und 25mm. Ihr Volumenanteil im Feuerfestbeton liegt vorzugsweise zwischen 2% und 6%.The length of the glass fibers is preferably between 12 and 25 mm. Their volume fraction in refractory concrete is preferably between 2% and 6%.

Zur Herstellung einer Spulenauskleidung bzw. Spuleneinbettung aus Feuerfestbeton werden zwei Verfahren angegeben.Two methods are specified for producing a coil lining or coil embedding from refractory concrete.

Ein erfindungsgemäßes Verfahren enthält die Verfahrensschritte:

  • a) Anrühren des gießfesten Feuerfestbetons in ansich bekannter Weise,
  • b) auf Länge Schneiden alkalibeständiger Glasfasern,
  • c) Beimischen der Glasfasern zum Feuerfestbeton und Herstellung einer gleichmäßigen Mischung und
  • d) Ausgießen, Ausschmieren bzw. Einbetten der Spule
mit/in Feuerfestbeton in ansich bekannter Weise.A method according to the invention contains the method steps:
  • a) mixing the pourable refractory concrete in a manner known per se,
  • b) cutting alkali-resistant glass fibers to length,
  • c) adding the glass fibers to the refractory concrete and producing an even mixture and
  • d) Pour out, lubricate or embed the coil
with / in refractory concrete in a known manner.

Ein zweites erfindungsgemäßes Verfahren ist dadurch gekennzeichnet, daß der in ansich bekannter Weise hergestellte Feuerfestbeton aus einer auf die Spule ausgerichteten Ringdüse herausgepreßt wird, wobei ihm gleichzeitig die im Spritzkopf auf Länge geschnittenen Glasfasern zugemischt werden. Dieses Verfahren hat den Vorteil, daß die Verteilung der Glasfasern im Beton gleichmäßiger ist als die im erstgenannten Verfahren und daß ein höherer Volumenanteil von Glasfasern im Feuerfestbeton erreichbar ist.A second method according to the invention is characterized in that the refractory concrete, which is produced in a manner known per se, is pressed out of an annular nozzle aligned with the coil, the glass fibers cut to length in the spray head being admixed to it at the same time. This method has the advantage that the distribution of the glass fibers in the concrete is more uniform than that in the first-mentioned method and that a higher volume fraction of glass fibers in refractory concrete can be achieved.

An Hand der Zeichnung, in der ein Ausführungsbeispiel der Erfindung gezeigt ist, soll die Erfindung näher erläutert werden.On the basis of the drawing, in which an embodiment of the invention is shown, the invention will be explained in more detail.

Es zeigt:

  • Fig. 1 eine Induktionsspulenanordnung mit Werkstück im Längsschnitt und
  • Fig. 2 eine Induktionsspulenanordnung gemäß Fig. 1 im Querschnitt.
It shows:
  • Fig. 1 shows an induction coil assembly with workpiece in longitudinal section and
  • Fig. 2 shows an induction coil arrangement according to FIG. 1 in cross section.

Aus der Zeichnung ist eine einlagige isolierte Induktionsspulenwicklung 1 ersichtlich, die allseits, bis auf nicht dargestellte Zu- und Ableitungen, in Feuerfestbeton 2 eingebettet ist. Der Feuerfestbeton 2 ist quaderförmig dargestellt (er kann jedoch auch eine andere äußere Form, z.B. Zylinderform aufweisen) und weist eine zentrale Bohrung 3 auf, die koaxial mit der Induktiohsspulenwicklung 1 verläuft. Innerhalb der Bohrung 3 ist ein zylindrisches, metallisches Werkstück 4 angeordnet. Der Außendurchmesser des Werkstückes 4 ist deutlich geringer als der Innendurchmesser der Bohrung 3, so daß das Werkstück 4 ohne Berührung des Feuerfestbetons 2 axial verschoben werden kann.From the drawing, a single-layer insulated induction coil winding 1 can be seen, which is embedded in refractory concrete 2 on all sides, with the exception of supply and discharge lines, not shown. The refractory concrete 2 is shown in a cuboid shape (however, it can also have a different external shape, for example a cylindrical shape) and has a central bore 3 which runs coaxially with the inductor winding 1. A cylindrical, metallic workpiece 4 is arranged within the bore 3. The outside diameter of the workpiece 4 is significantly smaller than the inside diameter of the bore 3, so that the workpiece 4 can be moved axially without touching the refractory concrete 2 can.

Der Feuerfestbeton 2 enthält eine Bemischung von Glasfasern, wodurch seine Temperatur- wechselbeständigkeit erheblich heraufgesetzt ist.The refractory concrete 2 contains a mixture of glass fibers, which considerably increases its resistance to temperature changes.

Claims (5)

1. Spulenauskleidung bzw. Spuleneinbettung aus Feuerfestbeton (2) insbes. für Induktionsspulen (1), dadurch gekennzeichnet, daß in dem Feuerfestbeton (2) annähernd gleichmäßig verteilte, alkalibeständige Glasfasern enthalten sind. ' 1. Coil lining or coil embedding made of refractory concrete (2) in particular for induction coils (1), characterized in that the refractory concrete (2) contains approximately uniformly distributed, alkali-resistant glass fibers. ' 2. Spulenauskleidung bzw. Spuleneinbettung nach Anspruch 1, dadurch gekennzeichnet, daß die Länge der Glasfasern zwischen 12 und 25mm beträgt.2. Coil lining or coil embedding according to claim 1, characterized in that the length of the glass fibers is between 12 and 25mm. 3. Spulenauskleidung bzw. Spuleneinbettung nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß der Volumenanteil der Glasfasern im Feuerfestbeton (2) zwischen 2% und 6% liegt.3. Coil lining or coil embedding according to one of claims 1 or 2, characterized in that the volume fraction of the glass fibers in the refractory concrete (2) is between 2% and 6%. 4. Verfahren zur Herstellung einer Spulenauskleidung bzw. Spuleneinbettung aus Feuerfestbeton (2) insbesondere für Induktionsspulen (1), nach einem der Ansprüche 1 bis 3, gekennzeichnet durch folgende Vefahrensschritte: a) Anrühren des gießfesten Feuerfestbetons (2) in ansich bekannter Weise, b) auf Länge Schneiden alkalibeständiger Glasfasern, c) Beimischen der Glasfasern zum Feuerfestbeton (2) und Herstellung einer gleichmäßigen Mischung und d) Ausgießen, Ausschmieren bzw. Einbetten der Spule mit/in dem so hergestellten Feuerfestbeton (2) in ansich bekannter Weise. 4. A method for producing a coil lining or coil embedding made of refractory concrete (2), in particular for induction coils (1), according to one of claims 1 to 3, characterized by the following method steps: a) stirring the pourable refractory concrete (2) in a manner known per se, b) cutting alkali-resistant glass fibers to length, c) adding the glass fibers to the refractory concrete (2) and producing an even mixture and d) pouring, lubricating or embedding the coil with / in the refractory concrete (2) thus produced in a manner known per se. 5. Verfahren zur Herstellung einer Spulenauskleidung bzw. Spuleneinbettung aus Feuerfestbeton (2), insbes. für Induktionsspulen (1), nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der in ansich bekannter Weise hergestellte Feuerfestbeton (2) durch eine auf die Spule ausgerichtete Ringdüse herausgepreßt wird, wobei ihm gleichzeitig die im Spritzkopf auf Länge geschnittenen Glasfasern zugesetzt werden.5. A method for producing a coil lining or coil embedding made of refractory concrete (2), in particular for induction coils (1), according to one of claims 1 to 3, characterized in that the refractory concrete (2) produced in a manner known per se is pressed out through an annular nozzle aligned with the spool, at the same time adding the glass fibers cut to length in the spray head.
EP82111239A 1981-12-11 1982-12-04 Coil coating or coil embedding of refractory concrete, and method of manufacturing it Withdrawn EP0081776A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3149030 1981-12-11
DE19813149030 DE3149030A1 (en) 1981-12-11 1981-12-11 COIL LINING OR REFRACTIVE CONCRETE BOBBLE EMBEDDING AND METHOD FOR THE PRODUCTION THEREOF

Publications (2)

Publication Number Publication Date
EP0081776A2 true EP0081776A2 (en) 1983-06-22
EP0081776A3 EP0081776A3 (en) 1984-02-22

Family

ID=6148433

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82111239A Withdrawn EP0081776A3 (en) 1981-12-11 1982-12-04 Coil coating or coil embedding of refractory concrete, and method of manufacturing it

Country Status (3)

Country Link
EP (1) EP0081776A3 (en)
JP (1) JPS58104055A (en)
DE (1) DE3149030A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2184927A (en) * 1985-12-27 1987-07-01 Ajax Magnethermic Corp Improvements in induction heater

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD59267A (en) *
AT140833B (en) * 1931-12-09 1935-02-25 Siemens Ag Process for making crucibles and furnace stoves
GB1290528A (en) * 1969-07-28 1972-09-27
FR2120564A5 (en) * 1971-01-08 1972-08-18 Stel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2184927A (en) * 1985-12-27 1987-07-01 Ajax Magnethermic Corp Improvements in induction heater
US4754114A (en) * 1985-12-27 1988-06-28 Ajax Magnethermic Corporation Induction heater

Also Published As

Publication number Publication date
DE3149030A1 (en) 1983-06-16
JPS58104055A (en) 1983-06-21
EP0081776A3 (en) 1984-02-22

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Effective date: 19841023

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Inventor name: MERTENS, MANFRED, ING. GRAD.