EP0037788B1 - Installation and process for melting metals or maintaining them in a molten state by means of an electrical immersion resistor heater - Google Patents

Installation and process for melting metals or maintaining them in a molten state by means of an electrical immersion resistor heater Download PDF

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Publication number
EP0037788B1
EP0037788B1 EP81400564A EP81400564A EP0037788B1 EP 0037788 B1 EP0037788 B1 EP 0037788B1 EP 81400564 A EP81400564 A EP 81400564A EP 81400564 A EP81400564 A EP 81400564A EP 0037788 B1 EP0037788 B1 EP 0037788B1
Authority
EP
European Patent Office
Prior art keywords
aluminium
installation
molten state
maintaining
volts
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.)
Expired
Application number
EP81400564A
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German (de)
French (fr)
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EP0037788A1 (en
Inventor
Jean Rouveyre
Alain Rouveyre
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.)
Fours Mgr Sa Dite Ste
Original Assignee
Fours Mgr Sa Dite Ste
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Publication date
Application filed by Fours Mgr Sa Dite Ste filed Critical Fours Mgr Sa Dite Ste
Priority to AT81400564T priority Critical patent/ATE11594T1/en
Publication of EP0037788A1 publication Critical patent/EP0037788A1/en
Application granted granted Critical
Publication of EP0037788B1 publication Critical patent/EP0037788B1/en
Expired 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
    • H05B3/00—Ohmic-resistance heating
    • H05B3/62—Heating elements specially adapted for furnaces
    • H05B3/64—Heating elements specially adapted for furnaces using ribbon, rod, or wire heater
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0006—Electric heating elements or system
    • F27D2099/0008—Resistor heating
    • F27D2099/0011—The resistor heats a radiant tube or surface
    • F27D2099/0013—The resistor heats a radiant tube or surface immersed in the charge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D21/0014—Devices for monitoring temperature

Definitions

  • the present invention relates to installations for melting a metallic material or for keeping molten material, as well as to methods for heating a molten material or for conducting electricity.
  • the fusion or maintenance of fusion of materials normally solid at room temperature, electrically conductive, such as metals, can be carried out in various installations.
  • the crucible furnace is heated by flames or by electric resistances, radiating energy on the crucible, the flame abrades and wears down the refractory materials constituting the furnace.
  • the electrical resistances do not withstand high temperatures.
  • a crucible induction furnace is expensive to install and maintain, in particular because of its inductors. Troubleshooting can only be carried out by specialist electronics engineers.
  • the invention overcomes these drawbacks by an installation that is inexpensive to install and maintain, in particular by the fact that its electrical equipment is simple, quick to start, able to operate with interruptions without inconvenience, giving more security, because operating at very low voltage, (especially between 5 and 15 volts) improving working conditions, because it does not pollute the atmosphere and does not create noise and makes it possible to achieve better performance than previous installations.
  • the subject of the invention is therefore an installation as defined according to claim 1.
  • these submerged elements are made of non-metallic material, such as graphite or silicon carbide, whose electrical resistivity is higher than that of the metal in which they are immersed, it is the resistant element (s) which preferentially undergo the '' heating by direct current flow.
  • non-metallic material such as graphite or silicon carbide
  • the metal in which the heating element (s) are immersed can be in the liquid, pasty or solid state, the only condition being that there is intimate contact between metal and immersed resistant element: the melting point of the element is higher than that of the metal by at least 100 ° C. preferably and better by at least 200 ° C.
  • the bath heating by plunging electrodes is a known process in which the weak resistance electrodes have the sole purpose of bringing the current to the bath which is itself resistant.
  • the system is reversed by the fact that the submerged element or elements are much more resistant than the metal in which they immerse, the latter having the role of closing the electrical circuit.
  • the cellar 1 or container of the oven is made of thermally insulating refractory material.
  • a resistant element 2 is immersed in the metal 3.
  • the current leads 4 and 5 are connected to the upper faces of the element 2 outside the bath.
  • the leads 4 and 5 are respectively connected to the terminals of the single-phase secondary of a step-down transformer 6 controlled by a regulation 7 suitable for thyristors, variable self or other controlled by sensors such as a pyrometric rod 8 or a telescope 9.
  • the heating is carried out by 3 elements 10, 11 and 12.
  • the current leads 13, 14 and 15 are respectively connected to the terminals of the three-phase secondary of a transformer 16 step-down controlled by a regulation 17 suitable for thyristors, variable inductor or other controlled by sensors such as pyrometric rod 18 or telescope 19 .

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)
  • Resistance Heating (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)

Abstract

1. Installation for melting aluminium or aluminium alloys or for keeping them in a molten state, comprising a container for molten aluminium and an electric circuit with an element immersed in the aluminium, this element consisting of a material with a higher melting point than aluminium, characterised in that the element consists of silicon carbide or graphite and the circuit is operated at a low voltage of about 5 to 15 volts.

Description

La présente invention se rapporte aux installations pour fondre une matière métallique ou pour maintenir en fusion une matière fondue, ainsi qu'aux procédés pour chauffer une matière fondue ou à fondre conductrice de l'électricité.The present invention relates to installations for melting a metallic material or for keeping molten material, as well as to methods for heating a molten material or for conducting electricity.

Pour retenir un alliage métallique fondu, c'est-à-dire pour l'empêcher de se répandre en le conservant, par exemple dans un four ou un creuset, il est connu de chauffer le récipient que constitue le creuset ou le four, afin que celui-ci transmette la chaleur qu'il reçoit à la masse en fusion qu'il contient.To retain a molten metal alloy, that is to say to prevent it from spreading by preserving it, for example in an oven or a crucible, it is known to heat the container that constitutes the crucible or the oven, in order that it transmits the heat it receives to the molten mass it contains.

La fusion ou le maintien en fusion de matières normalement solides à la température ambiante, conductrices de l'électricité, telles que les métaux, peut s'effectuer dans des installations diverses.The fusion or maintenance of fusion of materials normally solid at room temperature, electrically conductive, such as metals, can be carried out in various installations.

Le four à creuset est chauffé par flammes ou par des résistances électriques, rayonnant de l'énergie sur le creuset, la flamme abrase et use les matériaux réfractaires constitutifs du four. Les résistances électriques ne supportent pas des températures élevées.The crucible furnace is heated by flames or by electric resistances, radiating energy on the crucible, the flame abrades and wears down the refractory materials constituting the furnace. The electrical resistances do not withstand high temperatures.

Un four à induction à creuset est coûteux à installer et à entretenir notamment en raison de ses inducteurs. Le dépannage ne peut être effectué que par des électroniciens spécialisés.A crucible induction furnace is expensive to install and maintain, in particular because of its inductors. Troubleshooting can only be carried out by specialist electronics engineers.

Pour un four à induction à canal, où le métal contenu dans le canal s'échauffe sous l'effet des courants induits créés par une bobine d'induction et par un noyau magnétique englobant le canal, il faut, sous peine d'en abréger beaucoup la longévité, laisser toujours du métal liquide dans le canal, ce qui impose un fonctionnement ininterrompu. La puissance installée est limitée de sorte que la vitesse de fusion est petite. La réfection des réfractaires est onéreuse.For a channel induction furnace, where the metal contained in the channel heats up under the effect of the induced currents created by an induction coil and by a magnetic core encompassing the channel, it is necessary, under penalty of shortening it much longevity, always leave liquid metal in the channel, which requires uninterrupted operation. The installed power is limited so that the melting speed is small. The repair of refractories is expensive.

En outre, le rendement de ces installations connues est médiocre.In addition, the performance of these known installations is poor.

L'invention pallie ces inconvénients par une installation peu coûteuse à installer et à entretenir, notamment par le fait que son équipement électrique est simple, rapide à démarrer, pouvant fonctionner avec des interruptions sans inconvénient, donnant plus de sécurité, parce que fonctionnant à très basse tension, (notamment entre 5 et 15 volts) améliorant les conditions de travail, parce que ne polluant pas l'atmosphère et ne créant pas de bruit et permettant d'atteindre un meilleur rendement que les installations antérieures.The invention overcomes these drawbacks by an installation that is inexpensive to install and maintain, in particular by the fact that its electrical equipment is simple, quick to start, able to operate with interruptions without inconvenience, giving more security, because operating at very low voltage, (especially between 5 and 15 volts) improving working conditions, because it does not pollute the atmosphere and does not create noise and makes it possible to achieve better performance than previous installations.

L'invention a donc pour objet une installation telle que définie suivant la revendication 1.The subject of the invention is therefore an installation as defined according to claim 1.

Comme ce ou ces éléments immergés sont réalisés en matériau non métallique, tel que le graphite ou le carbure de silicium, dont la résistivité électrique est supérieure à celle du métal dans lequel ils sont immergés, ce sont le ou les éléments résistants qui subissent préférentiellement l'échauffement par passage direct du courant.As this or these submerged elements are made of non-metallic material, such as graphite or silicon carbide, whose electrical resistivity is higher than that of the metal in which they are immersed, it is the resistant element (s) which preferentially undergo the '' heating by direct current flow.

Dans le cas d'un seul élément bouclant un circuit électrique, il est appliqué à celui-ci un potentiel électrique à ses deux extrémités.In the case of a single element completing an electrical circuit, an electrical potential is applied to the latter at its two ends.

Dans le cas de plusieurs éléments, de préférence en un nombre qui est un multiple de 2 ou de 3, il est appliqué à chacun d'eux un potentiel électrique, le circuit se bouclant par le métal lui- même dans lequel ils sont immergés, ceci afin de réaliser un couplage électrique classique.In the case of several elements, preferably in a number which is a multiple of 2 or 3, an electrical potential is applied to each of them, the circuit being closed by the metal itself in which they are immersed, this in order to achieve a conventional electrical coupling.

Le métal dans lequel sont immergés le ou les éléments chauffants peut être à l'état liquide, pâteux ou solide, la seule condition étant qu'il y ait contact intime entre métal et élément résistant immergé : le point de fusion de l'élément est supérieur à celui du métal d'au moins 100 °C de préférence et mieux d'au moins 200 °C.The metal in which the heating element (s) are immersed can be in the liquid, pasty or solid state, the only condition being that there is intimate contact between metal and immersed resistant element: the melting point of the element is higher than that of the metal by at least 100 ° C. preferably and better by at least 200 ° C.

Le chauffage de bain par électrodes plongeantes est un procédé connu dans lequel les électrodes peu résistantes ont pour seul but d'amener le courant au bain qui, lui, est résistant.The bath heating by plunging electrodes is a known process in which the weak resistance electrodes have the sole purpose of bringing the current to the bath which is itself resistant.

Suivant l'invention, le système est inversé par le fait que le ou les éléments immergés sont beaucoup plus résistants que le métal dans lequel ils plongent, ce dernier ayant comme rôle de fermer le circuit électrique.According to the invention, the system is reversed by the fact that the submerged element or elements are much more resistant than the metal in which they immerse, the latter having the role of closing the electrical circuit.

Aux dessins annexés, donnés uniquement à titre d'exemple :

  • la figure 1 est un schéma vu en coupe d'un four suivant l'invention avec chauffage par un élément
  • la figure 2 est un schéma vu en coupe d'un four suivant l'invention avec chauffage par 3 éléments.
In the accompanying drawings, given solely by way of example:
  • Figure 1 is a diagram seen in section of an oven according to the invention with heating by an element
  • Figure 2 is a diagram seen in section of an oven according to the invention with heating by 3 elements.

A la figure 1, la cave 1 ou récipient du four est en matériau réfractaire thermiquement isolant.In FIG. 1, the cellar 1 or container of the oven is made of thermally insulating refractory material.

Un élément résistant 2 est immergé dans le métal 3.A resistant element 2 is immersed in the metal 3.

Les amenées de courant 4 et 5 sont raccordées sur les faces supérieures de l'élément 2 hors bain.The current leads 4 and 5 are connected to the upper faces of the element 2 outside the bath.

Les amenées 4 et 5 sont reliées respectivement aux bornes du secondaire monophasé d'un transformateur 6 abaisseur de tension commandé par une régulation 7 appropriée à thyristors, self variable ou autre commandés par des capteurs tels qu'une canne pyrométrique 8 ou une lunette 9.The leads 4 and 5 are respectively connected to the terminals of the single-phase secondary of a step-down transformer 6 controlled by a regulation 7 suitable for thyristors, variable self or other controlled by sensors such as a pyrometric rod 8 or a telescope 9.

A la figure 2, le chauffage est réalisé par 3 éléments 10, 11 et 12.In FIG. 2, the heating is carried out by 3 elements 10, 11 and 12.

Les amenées de courant 13, 14 et 15 sont reliées respectivement aux bornes du secondaire triphasé d'un transformateur 16 abaisseur de tension commandé par une régulation 17 appropriée à thyristors, self variable ou autre commandés par des capteurs tels que canne pyrométrique 18 ou lunette 19.The current leads 13, 14 and 15 are respectively connected to the terminals of the three-phase secondary of a transformer 16 step-down controlled by a regulation 17 suitable for thyristors, variable inductor or other controlled by sensors such as pyrometric rod 18 or telescope 19 .

Les essais suivants, effectués dans un four de 400 mm de diamètre, de 470 mm de profondeur et d'une capacité en aluminium de 100 kg, illustrent l'invention.The following tests, carried out in an oven 400 mm in diameter, 470 mm deep and with an aluminum capacity of 100 kg, illustrate the invention.

Premier essaiFirst try

On fond 100 kg d'aluminium en lingots à l'aide d'un brûleur à gaz. On immerge un élément chauffant en carbure de silicium ayant une résistivité de O,0050hms/cm/cm2 dans l'aluminium liquide (résistivité aluminium à froid : 2,82 microohms/cm2/cm).

  • - Tension sur l'élément : 10 Volts
  • - tension au primaire du transformateur : 390 V.
  • - Intensité : 110 A.
  • - Puissance appelée : 42,900 KVA
100 kg of aluminum are melted in ingots using a gas burner. A silicon carbide heating element having a resistivity of 0.0050hms / cm / cm2 is immersed in liquid aluminum (cold aluminum resistivity: 2.82 microohms / cm 2 / cm).
  • - Voltage on the element: 10 Volts
  • - transformer primary voltage: 390 V.
  • - Intensity: 110 A.
  • - Power demand: 42,900 KVA

Deuxième essaiSecond trial

On fond 100 kg d'aluminium en lingots à l'aide d'un brûleur à gaz, on immerge 2 éléments chauffants en carbure de silicium.

  • - Tension appliquée : 10 Volts
  • - tension au primaire du transformateur : 390 V.
  • - Intensité : 110 A.
  • - Puissance appelée = 42,9 KVA.
100 kg of aluminum are melted in ingots using a gas burner, 2 silicon carbide heating elements are immersed.
  • - Applied voltage: 10 Volts
  • - transformer primary voltage: 390 V.
  • - Intensity: 110 A.
  • - Power demand = 42.9 KVA.

Troisième essaiThird try

A la suite de l'essai précédent, les deux éléments sont mis hors tension afin de permettre la solidification de l'aluminium.Following the previous test, the two elements are de-energized to allow the solidification of the aluminum.

La solidification étant réalisée :

  • On met sous tension les éléments sous 10 Volts.
    • - Tension au primaire du transformateur : 390 Volts.
    • - Intensité : 90 A.
    • - Puissance appelée = 35,1 KVA.
Solidification being carried out:
  • The elements are energized under 10 Volts.
    • - Primary transformer voltage: 390 Volts.
    • - Intensity: 90 A.
    • - Power demand = 35.1 KVA.

Le métal fond par l'effet des éléments immergés; les valeurs relevées lors du 2e essai sont retrouvées.The metal melts by the effect of the submerged elements; readings taken during the 2nd test are found.

Claims (3)

1. Installation for melting aluminium or aluminium alloys or for keeping them in a molten state, comprising a container for molten aluminium and an electric circuit with an element immersed in the aluminium, this element consisting of a material with a higher melting point than aluminium, characterised in that the element consists of silicon carbide or graphite and the circuit is operated at a low voltage of about 5 to 15 volts.
2. Installation as claimed in claim 1, characterised in that the electric circuit comprises a voltage lowering transformer, the secondary of which is closed by one element or a plurality of elements and by the aluminium.
3. Process for melting aluminium or aluminium alloys or for keeping them in a molten state, characterised in that it comprises putting them in the container of an installation as claimed in claim 1 or 2 and passing a voltage through the circuit.
EP81400564A 1980-04-09 1981-04-09 Installation and process for melting metals or maintaining them in a molten state by means of an electrical immersion resistor heater Expired EP0037788B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81400564T ATE11594T1 (en) 1980-04-09 1981-04-09 APPARATUS AND METHOD FOR MELTING OR KEEPING METALS LIQUID BY MEANS OF AN ELECTRIC RESISTANCE APPLICATION ELEMENT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8007966A FR2480419A1 (en) 1980-04-09 1980-04-09 INSTALLATION AND METHOD FOR MELTING OR MAINTAINING A METAL MATERIAL BY IMMERSION RESISTANT ELEMENT IN METAL
FR8007966 1980-04-09

Publications (2)

Publication Number Publication Date
EP0037788A1 EP0037788A1 (en) 1981-10-14
EP0037788B1 true EP0037788B1 (en) 1985-01-30

Family

ID=9240681

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81400564A Expired EP0037788B1 (en) 1980-04-09 1981-04-09 Installation and process for melting metals or maintaining them in a molten state by means of an electrical immersion resistor heater

Country Status (4)

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EP (1) EP0037788B1 (en)
AT (1) ATE11594T1 (en)
DE (1) DE3168580D1 (en)
FR (1) FR2480419A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3512868A1 (en) * 1985-04-04 1986-10-09 W. Strikfeldt & Koch Gmbh, 5276 Wiehl OVEN, ESPECIALLY MELTING OR WARMING OVEN FOR METAL
US6451248B1 (en) * 2001-01-25 2002-09-17 Alcoa, Inc. Pressurized molten metal holder furnace

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR400655A (en) * 1908-06-15 1909-08-04 Charles Albert Keller Control system for circuits feeding electric multi-electrode furnaces
DE717668C (en) * 1937-06-12 1942-02-20 Siemens Planiawerke Ag Electric furnace with electric resistance heating elements
US2355761A (en) * 1943-04-23 1944-08-15 Commerce Pattern Foundry & Mac Electrically heated molten bath furnace
DE965835C (en) * 1949-03-22 1957-06-19 Otto Junker Fa Heating device for electric resistance furnaces, in particular melting furnaces
DE1058651B (en) * 1957-04-11 1959-06-04 Hettstedt Walzwerk Heating element with a resistance body made of glass for electric ovens
GB1042764A (en) * 1963-05-16 1966-09-14 Morganite Thermal Designs Ltd Improvements in and relating to electrically-heated furnaces
US3518351A (en) * 1968-12-16 1970-06-30 Carborundum Co Heating element

Also Published As

Publication number Publication date
FR2480419B1 (en) 1985-02-01
ATE11594T1 (en) 1985-02-15
EP0037788A1 (en) 1981-10-14
FR2480419A1 (en) 1981-10-16
DE3168580D1 (en) 1985-03-14

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