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EP0410829A1 - Process for heating a metallic bath - Google Patents

Process for heating a metallic bath Download PDF

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Publication number
EP0410829A1
EP0410829A1 EP90401858A EP90401858A EP0410829A1 EP 0410829 A1 EP0410829 A1 EP 0410829A1 EP 90401858 A EP90401858 A EP 90401858A EP 90401858 A EP90401858 A EP 90401858A EP 0410829 A1 EP0410829 A1 EP 0410829A1
Authority
EP
European Patent Office
Prior art keywords
heating
metallic
bath
metal
bath according
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Withdrawn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
EP90401858A
Other languages
German (de)
French (fr)
Inventor
Eric Duchateau
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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 Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Publication of EP0410829A1 publication Critical patent/EP0410829A1/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • 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
    • F27B14/08—Details specially adapted for crucible or pot furnaces
    • F27B14/14—Arrangements of heating devices
    • 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
    • F27B14/04—Crucible or pot furnaces adapted for treating the charge in vacuum or special atmosphere
    • 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
    • F27B14/08—Details specially adapted for crucible or pot furnaces
    • F27B2014/0875—Two zones or chambers, e.g. one used for charging
    • 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
    • F27B14/08—Details specially adapted for crucible or pot furnaces
    • F27B2014/0893—Heat-conductive material disposed on the surface of the melt
    • 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
    • F27D99/0033—Heating elements or systems using burners
    • F27D99/0035—Heating indirectly through a radiant surface

Definitions

  • the invention relates to a method of heating a metallic mass, in particular maintaining the fusion of a metallic bath, of the type in which radiant energy is developed in a space overhanging said metallic mass in the direction of the surface of the metallic mass. or metallic bath.
  • This kind of technique is mainly used in fusion in the so-called basin furnaces for the fusion and / or the maintenance of aluminum alloys, where the heat necessary for the fusion or the maintenance in fusion of the metal is provided by heating elements. placed in a vault and radiating directly on the load.
  • the vault temperatures are important (often above 1000 ° C) in order to be able to transfer the energy between the vault and the bath (bath temperature of the order of 700 ° C with aluminum alloys).
  • bath temperature of the order of 700 ° C with aluminum alloys.
  • the installed power must be much higher than the average energy consumed.
  • typically 80 kw of installed power is obtained for 30 kwh / h of average consumption.
  • this type of heat transfer promotes the formation of oxide concretions which destroy the refractories of the bath.
  • the process according to the invention makes it possible to avoid the abovementioned drawbacks, by propagating the radiant energy in an atmosphere of neutral gas, then through a floating sheet formed of transition elements made up of a plurality of plates in material good thermal conductor, good absorber of radiation, and density ensuring their buoyancy in the metal during heating. Thanks to the good absorption coefficient of the plates (of the order of 0.9), the thermal transfer between the plates and the radiating vault is improved, the heat then being transferred by conduction from the plates to the bath. The use of plates limits the aluminum deposits on the absorbent surface (the absorption coefficient of the surface therefore remains very good in use.
  • the inert atmosphere can be injected through the bath by a porous plug at the bottom of the basin or directly through the enclosure vault.
  • the inert gas flow is adjusted so as to maintain a slight overpressure in the enclosure. This eliminates air inlets and limits carbon oxidation and any risk of formation. carbon monoxide.
  • the slightly reducing or neutral atmosphere in the oven does not favor the development of concretions, which improves the service life of refractories.
  • the plate-shaped transition elements are made of graphite or carbon and the neutral gas is nitrogen and / or argon.
  • Such a holding oven comprises a basin 1 formed from a bottom 2 and side walls 3 and 4; it contains a liquid metal 5, for example an aluminum alloy.
  • An intake zone 6 of liquid metal or ingots is covered by a pivoting door 13 and, on the other hand, a zone 7 is used to withdraw liquid metal towards a molding machine.
  • the heating enclosure 8 with a vault 9 and side walls 10 plunging below the level of liquid bath.
  • the vault 9 is equipped with radiant heating means 12.
  • a neutral gas injector (not shown) in the enclosure 8 is formed either through a wall 10 of the enclosure, or in the form of a porous plug through the bottom 2 of the basin, directly above the enclosure 8, all so that the interior 11 of the enclosure 8 remains under low overpressure.
  • a hatch not shown, formed through the enclosure wall 10, a plurality of graphite or carbon 3 elements have been engaged on the surface of the molten metal bath in the form of thin plates (of the 'order of a few centimeters) so as to form a floating sheet covering most of the surface of the metal bath 5.
  • the invention applies primarily to the foundry of aluminum or aluminum alloys.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)

Abstract

Process for heating a metallic mass, particularly maintaining in the molten state a metallic bath (5) of the type in which an energy (12), radiating in a space above the said metallic mass (5), in the direction of the surface of the metallic mass or metallic bath (5), is developed. The radiating energy (12) is propagated in an atmosphere (11) of neutral gas then through a floating layer, formed of transition elements, consisting of a plurality of plates (3) made from a material which is a good conductor of heat, a good absorber of radiation, and of a density such as to ensure their floatability in the metal during heating. The invention applies firstly to aluminium or aluminium alloy casting practice. <IMAGE>

Description

L'invention concerne un procédé de chauffage d'une masse métallique, notamment maintien en fusion d'un bain métallique, du genre où l'on développe une énergie rayonnante dans un espace surplombant ladite masse métallique en direction de la surface de la masse métallique ou bain métallique.The invention relates to a method of heating a metallic mass, in particular maintaining the fusion of a metallic bath, of the type in which radiant energy is developed in a space overhanging said metallic mass in the direction of the surface of the metallic mass. or metallic bath.

Ce genre de technique est essentiellement utilisé en fusion dans les fours dits à bassin pour la fusion et/ou le maintien d'alliages d'aluminium, où la chaleur nécessaire à la fusion ou au maintien en fusion du métal est fournie par des éléments chauffants placés en voûte et rayonnant directement sur la charge.This kind of technique is mainly used in fusion in the so-called basin furnaces for the fusion and / or the maintenance of aluminum alloys, where the heat necessary for the fusion or the maintenance in fusion of the metal is provided by heating elements. placed in a vault and radiating directly on the load.

Le faible coéfficient d'absorption du métal liquide (coéfficient d'émissivité) pour l'aluminium liquide de l'ordre de 0,15 à 0,23) pose les problèmes suivants dans ce type de four :The low absorption coefficient of liquid metal (emissivity coefficient) for liquid aluminum of the order of 0.15 to 0.23) poses the following problems in this type of furnace:

Les températures de voûte sont importantes (souvent supérieures à 1000°C) afin de pouvoir transférer l'énergie entre la voûte et le bain (température de bain de l'ordre de 700°C avec les alliages d'aluminium). Les pertes thermiques par les réfractaires et l'usure des éléments chauffants augmentent à mesure que la température de la voûte s'élève.The vault temperatures are important (often above 1000 ° C) in order to be able to transfer the energy between the vault and the bath (bath temperature of the order of 700 ° C with aluminum alloys). The heat losses from the refractories and the wear of the heating elements increase as the temperature of the vault rises.

De ce fait, ces fours manquent de nervosité. Une remontée de la température du bain de quelques degrés (consécutive par exemple à l'arrivée d'une poche de métal liquide) peut prendre parfois plusieurs dizaines de minutes. Pendant ce laps de temps, la fabrication des pièces moulées est interrompue. Les arrêts peuvent donc perturber gravement la fabrication.As a result, these ovens lack nervousness. A rise in the temperature of the bath by a few degrees (following for example the arrival of a pocket of liquid metal) can sometimes take several tens of minutes. During this time, the production of the molded parts is interrupted. Stops can therefore seriously disrupt manufacturing.

D'autre part, la puissance installée doit être très supérieure à l'énergie moyenne consommée. Dans le cas d'un four de maintien d'alliages d'aluminium, on a typiquement 80 kw de puissance installée pour 30 kwh/h de consommation moyenne.On the other hand, the installed power must be much higher than the average energy consumed. In the case of an aluminum alloy holding furnace, typically 80 kw of installed power is obtained for 30 kwh / h of average consumption.

De plus, ce type de transfert thermique favorise la formation de concrétions d'oxydes qui détruisent les réfractaires du bain.In addition, this type of heat transfer promotes the formation of oxide concretions which destroy the refractories of the bath.

Pour tenter de résoudre ces problèmes, on a proposé de répandre sur le bain un corps pulvérulent absorbant le rayonnement (graphite ou SiC) et dont la densité est inférieure à celle de l'aluminium liquide. Cette manière de procéder n'est pas très efficace car le corps pulvérulent est oxydé par l'oxygène de l'air et disparaît de la surface du bain avec émission de monoxyde de carbone, ce qui présente un danger certain pour les opérateurs travaillant autour du four (risques d'intoxication et d'explosion). D'autre part les grains ont tendance à s'agglomérer avec l'aluminium, ce qui fait chuter le coefficient d'absorption de la surface.In an attempt to solve these problems, it has been proposed to spread over the bath a pulverulent body absorbing radiation (graphite or SiC) and whose density is lower than that of liquid aluminum. This procedure is not very effective because the pulverulent body is oxidized by oxygen in the air and disappears from the surface of the bath with the emission of carbon monoxide, which presents a certain danger for the operators working around the oven (risk of poisoning and explosion). On the other hand the grains tend to agglomerate with aluminum, which causes the absorption coefficient of the surface to drop.

Le procédé suivant l'invention permet d'éviter les inconvénients susmentionnés, en faisant propager l'énergie rayonnante dans une atmosphère de gaz neutre, puis au travers d'une nappe flottante formée d'éléments de transition constituée d'une pluralité de plaques en matériau bon conducteur thermique, bon absorbeur de rayonnement, et de densité assurant leur flottabilité dans le métal en cours de chauffage. Grâce au bon coefficient d'absorption des plaques (de l'ordre de 0,9) on améliore le transfert thermique entre les plaques et la voûte rayonnante, la chaleur étant ensuite transférée par conduction des plaques vers le bain. L'utilisation de plaques limite les dépôts d'aluminium sur la surface absorbante (le coefficient d'absorption de la surface reste donc très bon en utilisation. L'atmosphère inerte peut être injectée au travers du bain par un bouchon poreux au fond du bassin ou directement à travers la voûte d'enceinte. Le débit de gaz inerte est ajusté de façon à maintenir une légère surpression dans l'enceinte. On élimine ainsi les entrées d'air et on limite l'oxydation du carbone et tout risque de formation de monoxyde de carbone. L'atmosphère légèrement réductrice ou neutre dans le four ne favorise pas le développement des concrétions, ce qui permet d'améliorer la durée de vie des réfractaires.The process according to the invention makes it possible to avoid the abovementioned drawbacks, by propagating the radiant energy in an atmosphere of neutral gas, then through a floating sheet formed of transition elements made up of a plurality of plates in material good thermal conductor, good absorber of radiation, and density ensuring their buoyancy in the metal during heating. Thanks to the good absorption coefficient of the plates (of the order of 0.9), the thermal transfer between the plates and the radiating vault is improved, the heat then being transferred by conduction from the plates to the bath. The use of plates limits the aluminum deposits on the absorbent surface (the absorption coefficient of the surface therefore remains very good in use. The inert atmosphere can be injected through the bath by a porous plug at the bottom of the basin or directly through the enclosure vault. The inert gas flow is adjusted so as to maintain a slight overpressure in the enclosure. This eliminates air inlets and limits carbon oxidation and any risk of formation. carbon monoxide. The slightly reducing or neutral atmosphere in the oven does not favor the development of concretions, which improves the service life of refractories.

Le procédé selon l'invention permet en outre d'accroître notablement la nervosité des fours et leur productivité (diminution des arrêts de moulage). En effet, à température de voûte constante, l'énergie transférée au bain est nettementplus importante (en théorie accrue d'un facteur multiplicatif qui correspond au rapport des coefficients d'absorption des surfaces 0,9/0,2 = 4,5) dans la réalité, on constate que ce facteur multiplicatif est cependant plus faible.The method according to the invention also makes it possible to significantly increase the nervousness of the ovens and their productivity (reduction in molding stops). Indeed, at constant vault temperature, the energy transferred to the bath is much higher (in theory increased by a multiplicative factor which corresponds to the ratio of the absorption coefficients of the surfaces 0.9 / 0.2 = 4.5) in reality, we note that this multiplying factor is however weaker.

Selon un forme de mise en oeuvre, les éléments de transition en forme de plaques sont réalisés en graphite ou carbone et le gaz neutre est de l'azote et/ou argon.According to one embodiment, the plate-shaped transition elements are made of graphite or carbon and the neutral gas is nitrogen and / or argon.

L'invention est illustrée à titre d'exemple en référence au dessin annexé qui est une vue schématique en coupe d'un four de maintien en fusion opérant selon l'invention.The invention is illustrated by way of example with reference to the accompanying drawing which is a schematic sectional view of a melting holding furnace operating according to the invention.

Un tel four de maintien comporte un bassin 1 formé d'un fond 2 et de parois latérales 3 et 4 ; il contient un métal liquide 5, par exemple un alliage d'aluminium. Une zone d'admission 6 de métal liquide ou de lingots est recouverte par une porte pivotante 13 et à l'opposé une zone 7 sert à prélever du métal liquide vers une machine de moulage.Such a holding oven comprises a basin 1 formed from a bottom 2 and side walls 3 and 4; it contains a liquid metal 5, for example an aluminum alloy. An intake zone 6 of liquid metal or ingots is covered by a pivoting door 13 and, on the other hand, a zone 7 is used to withdraw liquid metal towards a molding machine.

Entre les zones 6 et 7 est ménagée l'enceinte de chauffage 8 à voûte 9 et parois latérales 10 plongeant en dessous du niveau de bain liquide. La voûte 9 est équipée de moyens de chauffage à rayonnement 12. Un injecteur de gaz neutre (non représenté) dans l'enceinte 8 est ménagé soit au travers d'une paroi 10 d'enceinte, soit sous forme de bonchon poreux au travers du fond 2 du bassin, à l'aplomb de l'enceinte 8, le tout de façon que l'intérieur 11 de l'enceinte 8 reste sous faible surpression.
Par une trappe non représentée, ménagée au travers de la paroi d'enceinte 10, on a engagé sur la surface du bain de métal en fusion une pluralité d'éléments de graphite ou de carbone 3 sous forme de plaques de faible épaisseur (de l'ordre de quelques centimètres) de façon à former une nappe flottante recouvrant la plus grande partie de la surface du bain métallique 5.Between zones 6 and 7 is formed the heating enclosure 8 with a vault 9 and side walls 10 plunging below the level of liquid bath. The vault 9 is equipped with radiant heating means 12. A neutral gas injector (not shown) in the enclosure 8 is formed either through a wall 10 of the enclosure, or in the form of a porous plug through the bottom 2 of the basin, directly above the enclosure 8, all so that the interior 11 of the enclosure 8 remains under low overpressure.
By a hatch, not shown, formed through the enclosure wall 10, a plurality of graphite or carbon 3 elements have been engaged on the surface of the molten metal bath in the form of thin plates (of the 'order of a few centimeters) so as to form a floating sheet covering most of the surface of the metal bath 5.

L'invention s'applique en premier lieu à la fonderie d'aluminium ou d'alliages d'aluminium.The invention applies primarily to the foundry of aluminum or aluminum alloys.

Claims (7)

1. Procédé de chauffage d'une masse métallique, notamment maintien en fusion d'un bain métallique, du genre où l'on développe une énergie rayonnante dans un espace surplombant ladite masse métallique en direction de la surface de la masse métallique, ou bain métallique, caractérisé en ce qu'on fait propager l'énergie rayonnante dans une atmosphère de gaz neutre puis au travers d'une nappe flottante formée d'éléments de transition constituée d'une pluralité de plaques en matériau bon conducteur thermique, bon absorbeur de rayonnement, et de densité assurant leur flottabilité dans le métal en cours de chauffage.1. A method of heating a metallic mass, in particular maintaining the fusion of a metallic bath, of the type in which radiant energy is developed in a space overhanging said metallic mass in the direction of the surface of the metallic mass, or bath metallic, characterized in that the radiant energy is propagated in an atmosphere of neutral gas and then through a floating sheet formed of transition elements consisting of a plurality of plates of material which is a good thermal conductor, a good absorber of radiation, and density ensuring their buoyancy in the metal during heating. 2. Procédé de chauffage d'un bain métallique selon la revendication 1, caractérisé en ce que les éléments de transition en forme de plaques sont réalisés en graphite ou carbone.2. A method of heating a metal bath according to claim 1, characterized in that the plate-shaped transition elements are made of graphite or carbon. 3. Procédé de chauffage d'un bain métallique selon la revendication 1, caractérisé en ce que la gaz neutre d'inertage d'atmosphère est de l'azote et/ou de l'argon.3. A method of heating a metal bath according to claim 1, characterized in that the neutral atmosphere inerting gas is nitrogen and / or argon. 4. Procédé de chauffage d'un bain métallique selon la revendication 1 ou 3, caractérisé en ce que l'atmosphère inerte est réalisée par injection de gaz inerte dans une enceinte en forme de cloche surplombant à pénétration latérale ledit bain liquide et incorporant en voûte les moyens de chauffage à énergie rayonnante.4. A method of heating a metal bath according to claim 1 or 3, characterized in that the inert atmosphere is produced by injecting inert gas into a bell-shaped enclosure overhanging with lateral penetration said liquid bath and incorporating a vault radiant energy heating means. 5. Procédé de chauffage d'un bain métallique selon la revendication 4, caractérisé en ce que l'injection de gaz inerte s'effectue au travers d'une paroi d'enceinte.5. A method of heating a metal bath according to claim 4, characterized in that the injection of inert gas is carried out through an enclosure wall. 6. Procédé de chauffage d'un bain métallique selon la revendication 4, caractérisé en ce que l'injection de gaz inerte s'effectue par le fond du bassin récepteur de métal liquide.6. A method of heating a metal bath according to claim 4, characterized in that the injection of inert gas is carried out through the bottom of the liquid metal receiving basin. 7. Application au procédé selon l'une quelconque des revendications 1 à 6 au four à voûte rayonnante de traitement de métaux à faible coefficient d'absorption, notamment d'aluminium ou d'alliage d'aluminium.7. Application to the method according to any one of claims 1 to 6 in a radiant vault for treating metals with a low absorption coefficient, in particular aluminum or aluminum alloy.
EP90401858A 1989-07-28 1990-06-28 Process for heating a metallic bath Withdrawn EP0410829A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8910222 1989-07-28
FR8910222A FR2650380A1 (en) 1989-07-28 1989-07-28 METHOD FOR HEATING A METAL BATH

Publications (1)

Publication Number Publication Date
EP0410829A1 true EP0410829A1 (en) 1991-01-30

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EP90401858A Withdrawn EP0410829A1 (en) 1989-07-28 1990-06-28 Process for heating a metallic bath

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EP (1) EP0410829A1 (en)
CA (1) CA2021303A1 (en)
FR (1) FR2650380A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5250026A (en) * 1992-05-27 1993-10-05 Destron/Idi, Inc. Adjustable precision transponder injector
CN105627745B (en) * 2016-03-18 2018-09-07 深圳市龙瑞泰兴能源环境科技有限公司 A kind of metal smelting furnace

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4027862A (en) * 1975-12-19 1977-06-07 Frank W. Schaefer Inc. Metal melting furnace with alternate heating systems
GB1561786A (en) * 1976-12-09 1980-03-05 Ass Eng Ltd Heating vessles for molten metal
US4353738A (en) * 1981-05-18 1982-10-12 Lectromelt Corporation Lead smelting method
DE3512868A1 (en) * 1985-04-04 1986-10-09 W. Strikfeldt & Koch Gmbh, 5276 Wiehl OVEN, ESPECIALLY MELTING OR WARMING OVEN FOR METAL
DE3739073A1 (en) * 1986-12-30 1988-07-14 Poppi Spa FURNACE FOR CERAMIC MATERIALS LIKE TILES AND SIMILAR

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4027862A (en) * 1975-12-19 1977-06-07 Frank W. Schaefer Inc. Metal melting furnace with alternate heating systems
GB1561786A (en) * 1976-12-09 1980-03-05 Ass Eng Ltd Heating vessles for molten metal
US4353738A (en) * 1981-05-18 1982-10-12 Lectromelt Corporation Lead smelting method
DE3512868A1 (en) * 1985-04-04 1986-10-09 W. Strikfeldt & Koch Gmbh, 5276 Wiehl OVEN, ESPECIALLY MELTING OR WARMING OVEN FOR METAL
DE3739073A1 (en) * 1986-12-30 1988-07-14 Poppi Spa FURNACE FOR CERAMIC MATERIALS LIKE TILES AND SIMILAR

Also Published As

Publication number Publication date
CA2021303A1 (en) 1991-01-29
FR2650380A1 (en) 1991-02-01

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