EP0111228B1 - Process and device for controlling the final filling of moulds with molten metal - Google Patents

Process and device for controlling the final filling of moulds with molten metal Download PDF

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Publication number
EP0111228B1
EP0111228B1 EP83111836A EP83111836A EP0111228B1 EP 0111228 B1 EP0111228 B1 EP 0111228B1 EP 83111836 A EP83111836 A EP 83111836A EP 83111836 A EP83111836 A EP 83111836A EP 0111228 B1 EP0111228 B1 EP 0111228B1
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EP
European Patent Office
Prior art keywords
coils
measuring
molten metal
moulds
measuring attachment
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EP83111836A
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German (de)
French (fr)
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EP0111228A1 (en
Inventor
Joachim Barzantny
Wilfried Leich
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LEICH ELEKTROOFENBAU-GIAPLAN GMBH
Interatom Internationale Atomreaktorbau GmbH
Original Assignee
Leich Elektroofenbau GmbH
Interatom Internationale Atomreaktorbau GmbH
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Priority to AT83111836T priority Critical patent/ATE21056T1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D39/00—Equipment for supplying molten metal in rations

Definitions

  • the present invention relates to a method according to the preamble of the main claim and an apparatus for performing the method.
  • the process should be suitable for metals with a high melting point.
  • a control device for feeding a melt into a casting mold in which the filling level in the pouring opening of the casting mold is contactless with the aid of an annular, surrounding the melt jet, current-carrying measuring coil is determined.
  • the signal from this measuring coil influences the control device and thus the supply of liquid metal.
  • the method proposed there serves on the one hand to regulate the supply of liquid metal during the casting process depending on the swallowing capacity of the casting mold and on the other hand to end the casting process when a predetermined fill level is reached. Problems arise, however, in that other factors influence the signal from the coil in addition to the level.
  • the object of the present invention is to provide a method and a device which make it possible to reproduce the final fill level in casting molds as precisely as possible.
  • the process should make do with components that are as simple as possible and that do not require any special adjustment or excessive maintenance. In this way, an automatic filling of many identical molds should be possible from a central control room.
  • the requirement for durability and low susceptibility to failure of the components used is also of crucial importance.
  • the measuring attachment z. B. can be implemented together with the casting furnace.
  • the induction coils in the measuring attachment, the mutual induction of which is a measure of the fill level, enable an exact measurement even at high and possibly somewhat fluctuating temperatures.
  • the termination of the supply of liquid metal can be achieved by actuators in connection with the * known potting mechanisms.
  • the threshold level so that the measuring attachment can be removed shortly after the end of the casting process without overflowing with liquid metal. Since the liquid metal level drops somewhat shortly after the end of the filling process when the liquid metal cools down, the threshold value for the final fill level can be adjusted accordingly so that the measuring attachment can be lifted off without problems a little later.
  • the conical filling funnel allows a mechanically simple but very exact positioning of the measuring attachment on every casting mold, so that the prerequisites for a reproducible filling level are created.
  • claim 4 proposes to provide the funnel-shaped measuring attachment at its upper end with a ceramic bead protruding beyond the coils to protect the coils.
  • the coils are then embedded in the space between the sand mold and the bead. This configuration prevents the coils from being damaged by splashes of liquid metal or other influences.
  • the ceramic material of the measuring attachment may only have a limited and much shorter lifespan than the coils
  • the measuring attachment according to claim 7 should be fastened in a holding and handling mechanism, which enables the measuring attachment to be automatically transferred from one mold to the next with the casting furnace.
  • This version is ideal because the measuring cone easily slips into its exact working position due to its conical shape, if it is implemented using a mechanism that should have sufficient play.
  • a sand mold 1 is shown with attached measuring attachment 2.
  • the measuring attachment is carried by a holding device 21 which is connected to the suspension 10 of a casting furnace 8 (or a ladle).
  • a drive 9 controls the outflow from the casting furnace 8.
  • a constant alternating current source 6 supplies the one coil of the measuring attachment with a constant alternating current, and the voltage induced in the second coil is registered by measuring and control electronics 7 and in control signals for the drive 9 of the Casting furnace 8 implemented. After reaching a predetermined fill level, the supply of liquid metal from the casting furnace 8 is stopped and the entire device is moved to the next mold.
  • the sand casting mold 1 has a filling channel 3 and above it a filling funnel 4.
  • the Measuring attachment 2 can be placed in such a way that its conical part 23 slides sealingly into the filling funnel 4.
  • the end 22 of the measuring attachment protruding into the filling funnel 4 results in exact positioning
  • the conical part 23 of the measuring attachment 2 is surrounded by at least two annular coils 24, 25.
  • One coil 24 serves as a transmission coil and its leads can be connected to a constant AC power source
  • the second coil 25 serves as a receiving coil and can be connected to measuring and control electronics 7.
  • a holder 21 carries the entire measuring attachment u nd, in conjunction with the mechanics of the casting furnace, enables the measuring attachment to be moved.
  • the measuring electronics When a certain fill level 5 of the molten metal is reached, the measuring electronics respond and stop the inflow of further liquid metal.
  • the magnetic field lines which in principle have to run around both coils in a closed path in order to effect an inductive coupling, are greatly weakened by eddy currents in the liquid metal, whereby simple geometrical considerations show that significant weakening already occurs at a fill level near the lower end 22 of the measuring attachment occurs. While the sand mold 1 can be penetrated just as well for the magnetic field lines as the ceramic parts of the measuring attachment 2, a few millimeters of liquid metal are practically impenetrable for magnetic field lines. This is the basis for precise measurements.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • General Induction Heating (AREA)

Abstract

1. A method of monitoring the final filling level during the filling of moulds (1), in particular sand moulds, with molten metal, which moulds have a poor electrical conductivity, characterized by the following features : a) an approximately funnel-shaped measuring attachment (2) is positioned on to the actual funnel tube (4) of the mould (1) prior to the commencement of the filling operation ; b) a change of the mutual induction of the coils (24, 25) included in the measuring attachment caused by the rising molten metal, is measured ; c) the supply of molten metal is stopped when a threshold value has been reached.

Description

Die vorliegende Erfindung betrifft ein Verfahren nach dem Oberbegriff des Hauptanspruchs und eine Vorrichtung zur Durchführung des Verfahrens. Insbesondere soll das Verfahren für Metalle mit einem hohen Schmelzpunkt geeignet sein.The present invention relates to a method according to the preamble of the main claim and an apparatus for performing the method. In particular, the process should be suitable for metals with a high melting point.

Aus der, den Oberbegriff der Ansprüche 1 und 3 bildenden CH-A-609 595 ist eine « Kontrolleinrichtung für die Zufuhr einer Schmelze in eine Gießform bekannt, bei der der Füllstand in der Eingußöffnung der Gießform berührungslos mit Hilfe einer ringförmigen, den Schmelzstrahl umgebenden, stromdurchflossenen Meßspule bestimmt wird. Das Signal dieser Meßspule beeinflußt die Stelleinrichtung und damit die Zufuhr von Flüssigmetall. Das dort vorgeschlagene Verfahren dient einerseits zur Regulierung der Zufuhr von Flüssigmetall während des Gießvorganges je nach dem Schluckvermögen der Gußform und andererseits zur Beendigung des Gießvorganges bei Erreichen eines vorbestimmten Füllstandes. Probleme treten allerdings dadurch auf, daß außer der Höhe des Füllstandes auch andere Faktoren das Signal der Spule beeinflussen.From CH-A-609 595, which forms the preamble of claims 1 and 3, a control device for feeding a melt into a casting mold is known, in which the filling level in the pouring opening of the casting mold is contactless with the aid of an annular, surrounding the melt jet, current-carrying measuring coil is determined. The signal from this measuring coil influences the control device and thus the supply of liquid metal. The method proposed there serves on the one hand to regulate the supply of liquid metal during the casting process depending on the swallowing capacity of the casting mold and on the other hand to end the casting process when a predetermined fill level is reached. Problems arise, however, in that other factors influence the signal from the coil in addition to the level.

So ist eine extrem genaue Positionierung der Spule in Bezug auf die Gießform und den Gießofen, insbesondere eine exakt waagerechte Einstellung, nötig und außerdem ist das Signal der Spule stark von der Temperatur abhängig, was unter anderem eine Kühlung und TemperaturkontrolJe erforderlich macht. Darüberhinaus beeinflußt alles umgebende Metall den Meßwert, so daß besondere Abschirmungsmaßnahmen notwendig sind.An extremely precise positioning of the coil in relation to the casting mold and the casting furnace, in particular an exactly horizontal setting, is necessary and the signal of the coil is strongly dependent on the temperature, which among other things requires cooling and temperature control. In addition, all surrounding metal influences the measured value, so that special shielding measures are necessary.

Aus der DE-OS-2638015 und der DE-OS-26 39 793 sind fernerhin optische Überwachungssysteme für den Füllstand von Flüssigmetall in einer Gießform bekannt. Auch diese weisen jedoch verschiedene Nachteile auf, die insbesondere im rauhen Alltagsbetrieb einer Gießereianlage zum Tragen kommen. So erfordern die optischen Systeme auch eine präzise Justierung und sind empfindlich gegenüber Verunreinigungen.From DE-OS-2638015 and DE-OS-26 39 793 optical monitoring systems for the level of liquid metal in a mold are also known. However, these also have various disadvantages, which are particularly noticeable in the rough everyday operation of a foundry system. The optical systems also require precise adjustment and are sensitive to contamination.

Aufgabe der vorliegenden Erfindung ist die Schaffung eines Verfahrens und einer Vorrichtung, die es ermöglichen, den Endfüllstand in Gußformen möglichst exakt reproduzierbar zu machen. Dabei soll das Verfahren mit möglichst einfachen Bauteilen auskommen, die keine besondere Justierung und keine übermäßige Wartung erfordern. Auf diese Weise soll ein automatisches Füllen von vielen gleichartigen Gußformen von einer zentralen Schaltwarte aus möglich sein. Von entscheidender Bedeutung ist auch die Forderung nach Haltbarkeit und geringer Störanfälligkeit der verwendeten Komponenten.The object of the present invention is to provide a method and a device which make it possible to reproduce the final fill level in casting molds as precisely as possible. The process should make do with components that are as simple as possible and that do not require any special adjustment or excessive maintenance. In this way, an automatic filling of many identical molds should be possible from a central control room. The requirement for durability and low susceptibility to failure of the components used is also of crucial importance.

Diese Aufgabe wird durch die Merkmale des Anspruchs 1 bzw. des Anspruchs 3, gelöst. Dabei kann der Meßaufsatz z. B. zusammen mit dem Gießofen umsetzbar sein. Die Induktionsspulen in dem Meßaufsatz, deren gegenseitige Induktion ein Maß für den Füllstand ist, ermöglichen eine exakte Messung auch bei hohen und gegebenenfalls etwas schwankenden Temperaturen. Die Beendigung der Zufuhr von Flüssigmetall kann durch Stellglieder in Verbindung mit den an sich bekannten* Vergießmechaniken erreicht werden.This object is achieved by the features of claim 1 and claim 3. The measuring attachment z. B. can be implemented together with the casting furnace. The induction coils in the measuring attachment, the mutual induction of which is a measure of the fill level, enable an exact measurement even at high and possibly somewhat fluctuating temperatures. The termination of the supply of liquid metal can be achieved by actuators in connection with the * known potting mechanisms.

Gemäß dem Anspruch 2 wird vorgeschlagen, den Schwellwert der Füllhöhe so einzustellen, daß der Meßaufsatz kurz nach dem Ende des Gießvorganges ohne Überfließen von Flüssigmetall wieder abgenommen werden kann. Da durch eine Volumenreduzierung beim Abkühlen des Flüssigmetalls der Flüssigmetallspiegel kurz nach dem Ende des Füllvorganges etwas absinkt, läßt sich durch entsprechende Einstellung des Schwellwertes für den Endfüllstand erreichen, daß wenig später der Meßaufsatz problemlos abgehoben werden kann. Der konische Einfülltrichter erlaubt eine mechanisch einfache aber sehr exakte Positionierung des Meßaufsatzes auf jede Gußform, so daß die Voraussetzungen für eine reproduzierbare Füllhöhe geschaffen sind.According to claim 2 it is proposed to set the threshold level so that the measuring attachment can be removed shortly after the end of the casting process without overflowing with liquid metal. Since the liquid metal level drops somewhat shortly after the end of the filling process when the liquid metal cools down, the threshold value for the final fill level can be adjusted accordingly so that the measuring attachment can be lifted off without problems a little later. The conical filling funnel allows a mechanically simple but very exact positioning of the measuring attachment on every casting mold, so that the prerequisites for a reproducible filling level are created.

Im Anspruch 3 wird eine Vorrichtung zur Durchführung des Verfahrens vorgeschlagen. Ein etwa trichterförmiger Meßaufsatz aus Keramikmaterial, welcher dichtend auf den eigentlichen Einfülltrichter der Gußform aufsetzbar ist, wird mit mindestens zwei Magnetspulen ausgestattet. Die Magnetspulen umgeben außen den konischen Teil des Meßaufsatzes. Mindestens eine der Spulen ist als Sendespule ausgelegt und an eine Wechselstromquelle anschließbar und mindestens eine andere Spule ist als Empfangsspule ausgelegt und an eine Meß- und Steuerelektronik anschließbar. Mit dieser Ausrüstung kann der Meßaufsatz besonders empfindlich das Ansteigen des Flüssigmetallspiegels in seinem Inneren nachweisen. Benutzt wird dabei ein an sich bekanntes Meßprinzip :

  • Das von der Sendespule erzeugbare elektromagnetische Feld induziert in der Empfangsspule eine Spannung, welche in einem Meßgerät registriert werden kann. Die Magnetfeldlinien laufen durch den von den beiden Spulen umgebenen Raum und bewirken solange eine gute magnetische Kopplung der Spulen, wie keine Unterbrechung der Magnetfeldlinien erfolgt. Wird jedoch ein elektrisch leitendes Material, beispielsweise ein Flüssigmetall in den von den Feldlinien durchlaufenen Raum gebracht, so werden in dem elektrischen Leiter (zumindest bei magnetischen Wechselfeldern) Wirbelströme erzeugt, welche ein entgegengesetztes Magnetfeld hervorrufen. Dies führt zu einer Schwächung der magnetischen Kopplung der Spulen und damit zu einer Verringerung der in der Empfangsspule induzierten Spannung. Je nach der Geometrie der Spulen und der Höhe der benutzten Frequenz ist ein empfindlicher Nachweis auch schon bei einer Annäherung des Flüssigmetallspiegels möglich. Bei Verwendung einer geeigneten Konstantwechselstromquelle läßt sich eine Messung mit sehr hoher absoluter Genauigkeit durchführen.
In claim 3, an apparatus for performing the method is proposed. An approximately funnel-shaped measuring attachment made of ceramic material, which can be placed sealingly on the actual filling funnel of the casting mold, is equipped with at least two magnetic coils. The outside of the magnetic coils surround the conical part of the measuring attachment. At least one of the coils is designed as a transmission coil and can be connected to an alternating current source and at least one other coil is designed as a reception coil and can be connected to measurement and control electronics. With this equipment, the measuring attachment can detect the rise of the liquid metal level in its interior in a particularly sensitive manner. A measuring principle known per se is used:
  • The electromagnetic field that can be generated by the transmitter coil induces a voltage in the receiver coil, which voltage can be registered in a measuring device. The magnetic field lines run through the space surrounded by the two coils and bring about a good magnetic coupling of the coils as long as the magnetic field lines are not interrupted. However, if an electrically conductive material, for example a liquid metal, is brought into the space through which the field lines pass, eddy currents are generated in the electrical conductor (at least in the case of alternating magnetic fields), which produce an opposite magnetic field. This leads to a weakening of the magnetic coupling of the coils and thus to a reduction in the voltage induced in the receiving coil. Depending on the geometry of the coils and the level of the frequency used, sensitive detection is also possible with one Approximation of the liquid metal level possible. If a suitable constant AC power source is used, a measurement can be carried out with very high absolute accuracy.

In besonderer Ausgestaltung der Erfindung schlägt der Anspruch 4 vor, den trichterförmigen Meßaufsatz an seinem oberen Ende mit einem über die Spulen hinausragenden keramischen Wulst zum Schutz der Spulen zu versehen. Die Spulen sind dann eingebettet in den Raum zwischen der Sandgußform und dem Wulst. Diese Ausgestaltung verhindert, daß die Spulen durch Spritzer von flüssigem Metall oder andere Einwirkungen beschädigt werden.In a special embodiment of the invention, claim 4 proposes to provide the funnel-shaped measuring attachment at its upper end with a ceramic bead protruding beyond the coils to protect the coils. The coils are then embedded in the space between the sand mold and the bead. This configuration prevents the coils from being damaged by splashes of liquid metal or other influences.

Da das keramische Material des Meßaufsatzes unter Umständen nur eine begrenzte und gegenüber den Spulen sehr viel kürzere Lebensdauer hat, wird in weiterer Ausgestaltung der Erfindung im Anspruch 5 vorgeschlagen, die Spulen zur Unterseite des abgenommenen Meßaufsatzes hin abnehmbar auszuführen. Insbesondere wird im Anspruch 6 vorgeschlagen, die Spulen mit ihren elektrischen Zuleitungen als eine auswechselbare Einheit zu gestalten, welche je nach Bedarf mit einem neuen keramischen Aufsatz versehen werden kann. Dies bewirkt, daß der aufwendigere Teil des Meßaufsatzes, nämlich die Spulen, ohne großen Aufwand und ohne Montage und Justierarbeiten mit einem neuen keramischen Mantel weiterbenutzt werden können.Since the ceramic material of the measuring attachment may only have a limited and much shorter lifespan than the coils, it is proposed in a further embodiment of the invention in claim 5 to make the coils detachable toward the underside of the removed measuring attachment. In particular, it is proposed in claim 6 to design the coils with their electrical feed lines as an interchangeable unit, which can be provided with a new ceramic attachment as required. This means that the more complex part of the measuring attachment, namely the coils, can be used with a new ceramic jacket without great effort and without assembly and adjustment work.

In weiterer Ausgestaltung der Erfindung wird vorgeschlagen, daß der Meßaufsatz gemäß dem Anspruch 7 in einer Halte- und Handhabungsmechanik befestigt sein soll, welche ein automatisches Umsetzen des Meßaufsatzes mit dem Gießofen von einer Gußform zur nächsten ermöglicht. Diese Ausführung bietet sich deshalb an, weil der Meßaufsatz durch die konische Form sehr leicht von selbst in seine exakte Arbeitsposition rutscht, wenn er mit Hilfe einer Mechanik, welche genügend Spiel aufweisen sollte, umgesetzt wird.In a further embodiment of the invention, it is proposed that the measuring attachment according to claim 7 should be fastened in a holding and handling mechanism, which enables the measuring attachment to be automatically transferred from one mold to the next with the casting furnace. This version is ideal because the measuring cone easily slips into its exact working position due to its conical shape, if it is implemented using a mechanism that should have sufficient play.

In besonderer Ausgestaltung der Erfindung wird im Anspruch 8 vorgeschlagen, das Spulensystem zusätzlich mit einer Temperaturmeßvorrichtung zu versehen, welche bei besonders hohen Anforderungen an die Genauigkeit der Messung eine Kompensation von temperaturbedingten Änderungen des Meßsignals ermöglicht.In a special embodiment of the invention, it is proposed in claim 8 to additionally provide the coil system with a temperature measuring device which, in the case of particularly high demands on the accuracy of the measurement, enables compensation of temperature-related changes in the measurement signal.

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und zwar zeigt

  • Figur 1 eine schematische Übersicht über die gesamte Anordnung,
  • Figur 2 einen Längsschnitt durch den oberen Teil einer Gußform mit aufgesetztem Meßaufsatz und
  • Figur 3 eine Ansicht von oben auf den Meßaufsatz.
An embodiment of the invention is shown in the drawing and shows
  • FIG. 1 shows a schematic overview of the entire arrangement,
  • Figure 2 shows a longitudinal section through the upper part of a mold with attached measuring attachment and
  • Figure 3 is a top view of the measuring attachment.

In Fig. 1 ist eine Sandgußform 1 mit aufgesetztem Meßaufsatz 2 dargestellt. Der Meßaufsatz wird von einer Haltevorrichtung 21 getragen, welche mit der Aufhängung 10 eines Gießofens 8 (oder einer Gießpfanne) verbunden ist. Ein Antrieb 9 steuert den Ausfluß aus dem Gießofen 8. Eine Konstantwechselstromquelle 6 versorgt die eine Spule des Meßaufsatzes mit einem konstanten Wechselstrom, und die in der zweiten Spule induzierte Spannung wird von einer Meß- und Steuerelektronik 7 registriert und in Steuersignale für den Antrieb 9 des Gießofens 8 umgesetzt. Nach Erreichen eines vorbestimmten Füllstandes wird die Zufuhr von Flüssigmetall aus des Gießofens 8 gestopt und die ganze Vorrichtung zur nächsten Gußform verfahren.In Fig. 1, a sand mold 1 is shown with attached measuring attachment 2. The measuring attachment is carried by a holding device 21 which is connected to the suspension 10 of a casting furnace 8 (or a ladle). A drive 9 controls the outflow from the casting furnace 8. A constant alternating current source 6 supplies the one coil of the measuring attachment with a constant alternating current, and the voltage induced in the second coil is registered by measuring and control electronics 7 and in control signals for the drive 9 of the Casting furnace 8 implemented. After reaching a predetermined fill level, the supply of liquid metal from the casting furnace 8 is stopped and the entire device is moved to the next mold.

In Fig. 2 und 3 ist der obere Teil einer Sandgußform mit aufgesetztem Meßaufsatz dargestellt (bzw. eine Ansicht von oben auf den Meßaufsatz. Die Sandgußform 1 weist einen Füllkanal 3 und darüber einen Einfülltrichter 4 auf. Auf den oberen Rand des Einfülltrichters 4 ist der Meßaufsatz 2 so aufsetzbar, daß sein konischer Teil 23 dichtend in den Einfülltrichter 4 hineingleitet. Das in den Einfülltrichter 4 ragende Ende 22 des Meßaufsatzes bewirkt eine exakte Positionierung. Der konische Teil 23 des Meßaufsatzes 2 ist von mindestens zwei ringförmigen Spulen 24, 25 umgeben. Die eine Spule 24 dient als Sendespule und ihre Zuleitungen sind an eine Konstantwechselstromquelle anschließbar. Die zweite Spule 25 dient als Empfangsspule und kann an eine Meß-und Steuerelektronik 7 angeschlossen werden. Die Zuleitungen der Spulen und gegebenenfalls eines nicht dargestellten Temperaturfühlers werden in einem gemeinsamen Schutzrohr 26 nach außen geführt. Eine Halterung 21 trägt den ganzen Meßaufsatz und ermöglicht in Verbindung mit der Mechanik des Gießofens ein Umsetzen des Meßaufsatzes.2 and 3 show the upper part of a sand casting mold with the measuring attachment attached (or a view from above of the measuring attachment. The sand casting mold 1 has a filling channel 3 and above it a filling funnel 4. On the upper edge of the filling funnel 4 there is the Measuring attachment 2 can be placed in such a way that its conical part 23 slides sealingly into the filling funnel 4. The end 22 of the measuring attachment protruding into the filling funnel 4 results in exact positioning The conical part 23 of the measuring attachment 2 is surrounded by at least two annular coils 24, 25. One coil 24 serves as a transmission coil and its leads can be connected to a constant AC power source, the second coil 25 serves as a receiving coil and can be connected to measuring and control electronics 7. The leads of the coils and, if appropriate, a temperature sensor (not shown) are in a common protective tube 26 led to the outside A holder 21 carries the entire measuring attachment u nd, in conjunction with the mechanics of the casting furnace, enables the measuring attachment to be moved.

Bei Erreichen eines bestimmten Füllstandsspiegels 5 der Metallschmelze spricht die Meßelektronik an und stopt den Zufluß von weiterem Flüssigmetall. Die Magnetfeldlinien, welche im Prinzip beide Spulen auf einem geschlossenen Weg umlaufen müssen, um eine induktive Kopplung zu bewirken, werden durch Wirbelströme im Flüssigmetall stark geschwächt, wobei schon einfache geometrische Überlegungen zeigen, daß eine bedeutende Schwächung schon bei einem Füllstand nahe dem unteren Ende 22 des Meßaufsatzes eintritt. Während die Sandgußform 1 für die Magnetfeldlinien ebenso gut durchdringbar ist wie die keramischen Teile des Meßaufsatzes 2, sind schon wenige Millimeter Flüssigmetall für Magnetfeldlinien praktisch undurchdringlich. Darin besteht die Grundlage für präzise Messungen.When a certain fill level 5 of the molten metal is reached, the measuring electronics respond and stop the inflow of further liquid metal. The magnetic field lines, which in principle have to run around both coils in a closed path in order to effect an inductive coupling, are greatly weakened by eddy currents in the liquid metal, whereby simple geometrical considerations show that significant weakening already occurs at a fill level near the lower end 22 of the measuring attachment occurs. While the sand mold 1 can be penetrated just as well for the magnetic field lines as the ceramic parts of the measuring attachment 2, a few millimeters of liquid metal are practically impenetrable for magnetic field lines. This is the basis for precise measurements.

Claims (8)

1. A method of monitoring the final filling level during the filling of moulds (1), in particular sand moulds, with molten metal, which moulds have a poor electrical conductivity, characterised by the following features :
a) an approximately funnel-shaped measuring attachment (2) is positioned on to the actual funnel tube (4) of the mould (1) prior to the commencement of the filling operation ;
b) a change of the mutual induction of the coils (24, 25) included in the measuring attachment caused by the rising molten metal, is measured ;
c) the supply of molten metal is stopped when a threshold value has been reached.
2. A method as claimed in Claim 1, characterised by the following feature :
a) the threshold value of the filling level is set to be such that shortly after the end of the casting process, the measuring attachment (2) can be removed without overflow of molten metal.
3. Apparatus for monitoring the final filling level during the filling with molten metal of moulds (1), in particular sand moulds, which have a poor electrical conductivity and are provided with a funnel tube (4), where the apparatus includes a measuring coil, characterised by the following features :
a) an approximately funnel-shaped measuring attachment (2) is provided which is made of a ceramic material and which can be positioned on to the actual funnel tube (4) of the sand mould (1) in sealing (22) fashion ;
b) after insertion, the conical part (23) of the measuring attachment (2) protrudes above the funnel tube (4) and is- surrounded by at least two magnetic coils (24, 25) ;
c) at least one of the coils (24, 25) is in the form of a transmitting coil (24) and can be connected to an a. c. source (6) ;
d) at least one of the coils (24, 25) is in the form of a receiving coil (25) and can be connected to a measuring and controlling electronic unit (7).
4. Apparatus as claimed in Claim 3, characterised by the following features :
a) at its upper end, the measuring attachment (2) has a ceramic extension (27) protruding over the coils ;
b) the foils (24, 25) fill the space between the sand mould (1) and the extension (27).
5. Apparatus as claimed in Claim 4, characterised by the following feature :
a) the coils (24, 25) are exchangeable from beneath with the measuring attachment (2) removed.
6. Apparatus as claimed in Claim 5, characterised by the following feature :
a) the coils (24, 25), together with their electric supply lines (26), form an exchangeable unit.
7. Apparatus as claimed in one of the preceding Claims, characterised by the following feature :
a) the measuring attachment (2) is fixed in a holding and handling mechanism (21) which allows the measuring attachment, together with the casting furnace (8), to be automatically changed from one mould (1) to the next.
8. Apparatus as claimed in one of the preceding Claims, characterised by the following feature :
a) in the region of the coils (24, 25), a temperature measuring device is arranged, the supply lines of which can also be connected to the measuring and controlling electronic unit (7).
EP83111836A 1982-12-10 1983-11-25 Process and device for controlling the final filling of moulds with molten metal Expired EP0111228B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83111836T ATE21056T1 (en) 1982-12-10 1983-11-25 METHOD AND DEVICE FOR MONITORING THE FINAL LEVEL WHEN FILLING MOLDS WITH LIQUID METAL.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3245832A DE3245832C1 (en) 1982-12-10 1982-12-10 Method and device for monitoring the final level when filling molds with liquid metal
DE3245832 1982-12-10

Publications (2)

Publication Number Publication Date
EP0111228A1 EP0111228A1 (en) 1984-06-20
EP0111228B1 true EP0111228B1 (en) 1986-07-30

Family

ID=6180380

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83111836A Expired EP0111228B1 (en) 1982-12-10 1983-11-25 Process and device for controlling the final filling of moulds with molten metal

Country Status (3)

Country Link
EP (1) EP0111228B1 (en)
AT (1) ATE21056T1 (en)
DE (2) DE3245832C1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017204441A1 (en) 2017-03-16 2018-09-20 Robert Bosch Gmbh Level measurement for raw material in a 3D printhead

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3423868A1 (en) * 1984-06-28 1986-01-02 Herbert Dipl.-Ing. 4030 Ratingen Tegelhütter Measurement coil device
DE3500978A1 (en) * 1985-01-14 1986-07-17 INTERATOM GmbH, 5060 Bergisch Gladbach METHOD FOR REGULATING A GIESS- OR. CONVEYOR DEVICE FOR FILLING A CAST MOLD WITH LIQUID METAL AND RELATED CAST MOLD AND DEVICE FOR IMPLEMENTING THE METHOD
DE3541967A1 (en) 1985-11-27 1987-06-04 Interatom FLAT INDUCTIVE LEVEL SENSOR FOR LIQUID METALS
ES2593655T3 (en) 2011-09-15 2016-12-12 Agellis Group Ab Level measurements in metallurgical vessels

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1487386A (en) * 1974-09-17 1977-09-28 Buhrer E Casting apparatuses and casting methods
CH615609A5 (en) * 1976-03-22 1980-02-15 Mezger Ed Maschinenfabrik & Ei
CH609595A5 (en) * 1976-06-15 1979-03-15 Fischer Ag Georg Monitoring arrangement for the supply of a melt to a casting mould
DE2638015A1 (en) * 1976-08-24 1978-03-02 Fischer Ag Georg Photoelectric monitor controlling casting speed of molten metal - flowing from a ladle into a mould

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017204441A1 (en) 2017-03-16 2018-09-20 Robert Bosch Gmbh Level measurement for raw material in a 3D printhead

Also Published As

Publication number Publication date
DE3365015D1 (en) 1986-09-04
EP0111228A1 (en) 1984-06-20
DE3245832C1 (en) 1983-11-03
ATE21056T1 (en) 1986-08-15

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