US3217368A - Metal flow regulation - Google Patents

Metal flow regulation Download PDF

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Publication number
US3217368A
US3217368A US21829962A US3217368A US 3217368 A US3217368 A US 3217368A US 21829962 A US21829962 A US 21829962A US 3217368 A US3217368 A US 3217368A
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Prior art keywords
metal
level
measuring
height
metal flow
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Expired - Lifetime
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Pototschnigg Gunter
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Alcan Holdings Switzerland AG
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Alusuisse Holdings AG
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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
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/18—Controlling or regulating processes or operations for pouring
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D9/00—Level control, e.g. controlling quantity of material stored in vessel
    • G05D9/12—Level control, e.g. controlling quantity of material stored in vessel characterised by the use of electric means
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/0318—Processes
    • Y10T137/0324—With control of flow by a condition or characteristic of a fluid
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7287—Liquid level responsive or maintaining systems
    • Y10T137/7306—Electrical characteristic sensing

Definitions

  • the principal object of the present invention is a method for maintaing the level of flowing liquid metal at a constant height, determining the height of the level by means of measuring an electrical capacity and regulating the metal flow as a function of the results of the capacity measurements.
  • a further object of the invention is an apparatus for carrying out the method of maintaining the level of flowing liquid metal at a constant height by means of measuring an electrical capacity.
  • the electrical capacity is measured between an electrically conducting plate, called measuring plate, arranged in distance above and parallel to the metal level, and the surface of the metal melt.
  • the measuring plate and the metal surface constitute a plate capacitor.
  • the metal flow determining the height of the metal level is regulated in function of the results of the capacity measurements, advantageously by means of an automatic control device.
  • the mentioned capacitor is part of an alternating current measuring bridge which is connected to a source of high frequency alternating current and to a control device.
  • the measuring bridge is of the kind of the known Wheatstone bridge.
  • the control device controls the metal flow, preferably the mechanism for tilting the liquid metal supply container.
  • the method according to the invention is usable for all metals, also for the ferrous metals in spite of their high melting point. But it is especially suitable for melts of non-ferrous metals, especially melts of aluminum and aluminum alloys, magnesium and magnesium alloys.
  • the invention is further described by means of the accompanying drawing showing a continuous casting equipment for aluminum.
  • the height of the metal level in the channel between a melting-furnace or a holding-furnace and the pouring gate above the continuous casting mold is to be determined and maintained at a constant height by regulating the tilting of the furnace and thus regulating the metal flow.
  • FIG. 1 is a side view of the equipment, not showing the pouring gate in front, and FIG. 2 is a plan View.
  • FIG. 1 shows also schematically the connection of the measuring device and the control device.
  • the casting channel 1 consists of cast iron covered with a wash; it has an inside width at AA of 6.5 cm., a depth of 5 cm. and a wall thickness of 0.8 to 1 cm. In a height of about 1 cm. above the edge of the channel at their bifurcation is placed the measuring plate 2 in form of a triangular iron sheet having a thickness of about 1 mm.
  • An intermediate layer of a non-conducting material for example asbestos, insulates the measuring plate from the channel and from the melt.
  • 3 designates the two pouring gates and 4 the casting molds. The lowering speed of the castings in the molds is regulated to be constant by any known regulating device.
  • the plate capacitor constituted by the measuring plate 2 and the metal surface 5 is part of the alternating current measuring bridge 6, in which the variations of the capacity due to the fluctuations of the metal level are measured.
  • the measuring bridge is energized by a source 7 of high frequency alternating current.
  • the casting equipment and therefore the metal melt on the one hand and the measuring bridge on the other hand are earthed.
  • the current flowing in the measuring bridge and corresponding to the variations of the capacity is magnified in the amplifier 8 and transformed in control pulses in the control device.
  • the control pulses actuate the tilting mechanism of the furnace.
  • the necessary voltage for the capacity measurement amounts to 4 to 6 volts and the current flowing in the measuring bridge is about 2.5 milliamperes.
  • the measuring plate 2 may consist of any material which is an electrical conductor, it is also possible to use a ceramic plate with a layer of evaporated metal.
  • the width of the plate depends on their distance from the surface of the metal melt.
  • the variations of the capacity due to the fluctuations of the metal level in the channel should amount to 3 t0 5 picofarad (3 to 5.10- Farad).
  • the frequency of the alternating current may lay within the range of 1 to 500 kHz.
  • the method for maintaining the level of flowing liquid metal at a constant height determining the height of the level by means of measuring the electrical capacity between an electrically conducting measuring plate arranged in distance above and parallel to the metal level, and the surface of the metal melt, and automatically regulating the metal flow in response to any change in the height of the level determined.
  • An apparatus for maintaining with the aid of a control device, at a constant height the level of liquid metal flowing in a channel structure supplied from a liquid metal supply container comprising an electrically conducting measuring plate arranged at a predetermined distance from said channel structure above and parallel to the upper surface of the liquid metal and forming with said surface an electric plate capacitor, said capacitor being part of an alternating current measuring bridge which is connected to a source of high frequency alternating current and to said control device operable for regulating the metal flow from said supply container to said channel structure.

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

Description

Nov. 16, 1965 G. POTOTSCHNIGG 3,217,368
METAL FLOW REGULATION Filed Aug. 21, 1962 INVENTOR: GUNTER POTOTSCHMGG,
H/5 ATTORNEX United States Patent 3,217,368 METAL FLOW REGULATION Giinter Pototschnigg, Singen am Hohentwiel, Germany,
assignor to Schweizerische Aluminium A.G., a jointstock company of Switzerland Filed Aug. 21, 1962, Ser. No. 218,299 Claims priority, application Switzerland, Aug. 22, 1961, 9,828/ 61 3 Claims. (CI. 22-79) In conveying liquid metal from a melting or holding furnace into a tundish or a casting channel leading to a continuous casting apparatus it is very important with respect to the quality of the casting to maintain a constant metal flow and therefore to hold the metal level at a constant height in the tundish or the channel.
There are known different methods for maintaining constant the level of a metal melt in a tundish by means of swimming devices or dipping electrodes controlling the discharge of the metal supply container, for example by tilting. There are also known methods for maintaining constant the level of the molten metal in a continuous casting mold.
The principal object of the present invention is a method for maintaing the level of flowing liquid metal at a constant height, determining the height of the level by means of measuring an electrical capacity and regulating the metal flow as a function of the results of the capacity measurements.
A further object of the invention is an apparatus for carrying out the method of maintaining the level of flowing liquid metal at a constant height by means of measuring an electrical capacity.
According to the invention the electrical capacity is measured between an electrically conducting plate, called measuring plate, arranged in distance above and parallel to the metal level, and the surface of the metal melt. The measuring plate and the metal surface constitute a plate capacitor. The metal flow determining the height of the metal level is regulated in function of the results of the capacity measurements, advantageously by means of an automatic control device. For this purpose the mentioned capacitor is part of an alternating current measuring bridge which is connected to a source of high frequency alternating current and to a control device. The measuring bridge is of the kind of the known Wheatstone bridge. The control device controls the metal flow, preferably the mechanism for tilting the liquid metal supply container.
The method according to the invention is usable for all metals, also for the ferrous metals in spite of their high melting point. But it is especially suitable for melts of non-ferrous metals, especially melts of aluminum and aluminum alloys, magnesium and magnesium alloys.
The invention is further described by means of the accompanying drawing showing a continuous casting equipment for aluminum. The height of the metal level in the channel between a melting-furnace or a holding-furnace and the pouring gate above the continuous casting mold is to be determined and maintained at a constant height by regulating the tilting of the furnace and thus regulating the metal flow.
FIG. 1 is a side view of the equipment, not showing the pouring gate in front, and FIG. 2 is a plan View. FIG. 1 shows also schematically the connection of the measuring device and the control device.
The casting channel 1 consists of cast iron covered with a wash; it has an inside width at AA of 6.5 cm., a depth of 5 cm. and a wall thickness of 0.8 to 1 cm. In a height of about 1 cm. above the edge of the channel at their bifurcation is placed the measuring plate 2 in form of a triangular iron sheet having a thickness of about 1 mm.
"ice
and a one side surface area of cm. An intermediate layer of a non-conducting material, for example asbestos, insulates the measuring plate from the channel and from the melt. 3 designates the two pouring gates and 4 the casting molds. The lowering speed of the castings in the molds is regulated to be constant by any known regulating device.
The plate capacitor, constituted by the measuring plate 2 and the metal surface 5 is part of the alternating current measuring bridge 6, in which the variations of the capacity due to the fluctuations of the metal level are measured. The measuring bridge is energized by a source 7 of high frequency alternating current. The casting equipment and therefore the metal melt on the one hand and the measuring bridge on the other hand are earthed. The current flowing in the measuring bridge and corresponding to the variations of the capacity is magnified in the amplifier 8 and transformed in control pulses in the control device. The control pulses actuate the tilting mechanism of the furnace. The necessary voltage for the capacity measurement amounts to 4 to 6 volts and the current flowing in the measuring bridge is about 2.5 milliamperes.
The measuring plate 2 may consist of any material which is an electrical conductor, it is also possible to use a ceramic plate with a layer of evaporated metal. The width of the plate depends on their distance from the surface of the metal melt. The variations of the capacity due to the fluctuations of the metal level in the channel should amount to 3 t0 5 picofarad (3 to 5.10- Farad). The frequency of the alternating current may lay within the range of 1 to 500 kHz.
What I claim is:
1. The method for maintaining the level of flowing liquid metal at a constant height, determining the height of the level by means of measuring the electrical capacity between an electrically conducting measuring plate arranged in distance above and parallel to the metal level, and the surface of the metal melt, and automatically regulating the metal flow in response to any change in the height of the level determined.
2. The method according to claim 1, in which method the metal flow is regulated by actuating the tilting mechanism of a liquid metal supply container according to the results of the capacity measurements.
3. An apparatus for maintaining with the aid of a control device, at a constant height the level of liquid metal flowing in a channel structure supplied from a liquid metal supply container, said apparatus comprising an electrically conducting measuring plate arranged at a predetermined distance from said channel structure above and parallel to the upper surface of the liquid metal and forming with said surface an electric plate capacitor, said capacitor being part of an alternating current measuring bridge which is connected to a source of high frequency alternating current and to said control device operable for regulating the metal flow from said supply container to said channel structure.
References Cited by the Examiner UNITED STATES PATENTS 2,743,492 5/ 6 Easton 22-79 2,762,096 9/ 1956 Wittmoser 22-79 2,922,205 1/ 1960 Deakins et a1. 2282 2,981,818 4/ 1961 Trabilcy 22-79 FOREIGN PATENTS 617,911 2/ 1949 Great Britain. 762,311 1 1/ 195 6 Great Britain.
WILLIAM J. STEPHENSON, Primary Examiner.

Claims (1)

1. THE METHOD FOR MAINTAINING THE LEVEL OF FLOWING LIQUID METAL AT A CONSTANT HEIGHT, DETERMINING THE HEIGHT OF THE LEVEL BY MEANS OF MEASURING THE ELECTRICAL CAPACITY BETWEEN AN ELECTRICALLY CONDUCTING MEASURING PLATE ARRANGED IN DISTANCE ABOVE AND PARALLEL TO THE METAL LEVEL, AND THE SURFACE OF THE METAL MELT, AND AUTOMATICALLY REGULATING THE METAL FLOW IN RESPONSE TO ANY CHANGE IN THE HEIGHT OF THE LEVEL DETERMINED.
US21829962 1961-08-22 1962-08-21 Metal flow regulation Expired - Lifetime US3217368A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH982861A CH389170A (en) 1961-08-22 1961-08-22 Method for keeping the level of a molten metal constant

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3304587A (en) * 1964-05-18 1967-02-21 Loren J Hov Electron beam overflow melting method and means
US4520948A (en) * 1980-12-08 1985-06-04 Jacobs Beverage Systems Ag Disposable container for liquids and apparatus for dispensing liquid from such container
CN103084232A (en) * 2011-10-28 2013-05-08 奈斯莱博热电公司 Circulating Liquid Bath With Reservoir Dual Level Switch

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPM830094A0 (en) * 1994-09-20 1994-10-13 Comalco Aluminium Limited Apparatus and method for the supply of molten metal (charging during casting)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB617911A (en) * 1946-05-16 1949-02-14 Stanley James Smith Improvements relating to apparatus for controlling the distribution of fuel in aircraft
US2743492A (en) * 1953-04-20 1956-05-01 Allegheny Ludlum Steel Apparatus for controlling the flow of molten metal
US2762096A (en) * 1955-04-27 1956-09-11 Eisenwerke Gelsenkirchen Ag Metal casting apparatus
GB762311A (en) * 1954-04-28 1956-11-28 Continuous Casting Company Ltd Improvements relating to tundishes
US2922205A (en) * 1957-05-07 1960-01-26 Combustion Eng Automatic weighing and pouring of molten metal into pairs of foundry molds
US2981818A (en) * 1958-12-17 1961-04-25 Electric Pipe Line Inc Type metal transportation system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB617911A (en) * 1946-05-16 1949-02-14 Stanley James Smith Improvements relating to apparatus for controlling the distribution of fuel in aircraft
US2743492A (en) * 1953-04-20 1956-05-01 Allegheny Ludlum Steel Apparatus for controlling the flow of molten metal
GB762311A (en) * 1954-04-28 1956-11-28 Continuous Casting Company Ltd Improvements relating to tundishes
US2762096A (en) * 1955-04-27 1956-09-11 Eisenwerke Gelsenkirchen Ag Metal casting apparatus
US2922205A (en) * 1957-05-07 1960-01-26 Combustion Eng Automatic weighing and pouring of molten metal into pairs of foundry molds
US2981818A (en) * 1958-12-17 1961-04-25 Electric Pipe Line Inc Type metal transportation system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3304587A (en) * 1964-05-18 1967-02-21 Loren J Hov Electron beam overflow melting method and means
US4520948A (en) * 1980-12-08 1985-06-04 Jacobs Beverage Systems Ag Disposable container for liquids and apparatus for dispensing liquid from such container
CN103084232A (en) * 2011-10-28 2013-05-08 奈斯莱博热电公司 Circulating Liquid Bath With Reservoir Dual Level Switch
CN103084232B (en) * 2011-10-28 2016-11-23 奈斯莱博热电公司 There is the circulation liquid pool of twin containers liquid-level switch
US10532359B2 (en) 2011-10-28 2020-01-14 Thermo Neslab Llc Circulating liquid bath with dual reservoir level switch

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CH389170A (en) 1965-03-15
GB947563A (en) 1964-01-22

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