EP0018326B1 - Hood for an aluminium reduction cell - Google Patents

Hood for an aluminium reduction cell Download PDF

Info

Publication number
EP0018326B1
EP0018326B1 EP80810122A EP80810122A EP0018326B1 EP 0018326 B1 EP0018326 B1 EP 0018326B1 EP 80810122 A EP80810122 A EP 80810122A EP 80810122 A EP80810122 A EP 80810122A EP 0018326 B1 EP0018326 B1 EP 0018326B1
Authority
EP
European Patent Office
Prior art keywords
plates
cover
cover plates
cell
steel
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
EP80810122A
Other languages
German (de)
French (fr)
Other versions
EP0018326A1 (en
Inventor
Donald R. Bradford
James E. White
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.)
Alcan Holdings Switzerland AG
Original Assignee
Schweizerische Aluminium AG
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 Schweizerische Aluminium AG filed Critical Schweizerische Aluminium AG
Priority to AT80810122T priority Critical patent/ATE9233T1/en
Publication of EP0018326A1 publication Critical patent/EP0018326A1/en
Application granted granted Critical
Publication of EP0018326B1 publication Critical patent/EP0018326B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes

Definitions

  • the present invention relates to a cover for an aluminum reduction cell operating in the melt flow, with a trough containing the separated liquid metal and the electrolyte and a plurality of carbon anodes immersed in the molten electrolyte, the cover covering a container covering the area between the two anode support sides with an as Wing formed lower edge and several of this edge over the entire longitudinal direction of the cell to the board of the electrolysis tub sloping mobile cover plates.
  • the electrolysis cells work with currents of 45-225 kA (kiloamperes).
  • Typical aluminum reduction cells include a coal pan surrounded by insulating material. The bottom of the coal trough is provided with embedded steel bars through which the electrolysis current flows, the trough acts as the cathode of the reduction cell.
  • the tub is partially filled with an aluminum bath on which the essentially melted cryolite (Na 3 AIF 6 ) and clay (AI 2 0 3 ) dissolved therein contains electrolyte.
  • One or more carbon anodes are immersed in the molten electrolyte. During the passage of the direct current from the carbon anodes to the liquid aluminum, the Al 2 0 3 dissolved in the electrolyte is dissociated.
  • U.S. Patent 3,948,749 shows a typical hood arrangement.
  • This patent shows a conventional hood, which has a large number of plates, the size and weight of which is intended to enable convenient and easy removal by hand, so that easy access is ensured for viewing and operating the cell.
  • This requirement for lighter, hand-removable plates means that a large number of plates must be used to encapsulate the reduction cell, which results in a corresponding increase in the number of surfaces to be sealed and connections to be sealed.
  • the plates are typically made of light aluminum or aluminum alloys to mitigate the effects of the high magnetic folders that would occur with steel plates, because these magnetic fields would increase the force required to remove the plates. When using aluminum, the weight of the plates can therefore be considerably reduced.
  • the inventors have therefore set themselves the task of creating a cover for an aluminum cell working in the melt flow, which has a high efficiency for collecting the gases, can be easily removed by hand and is not damaged by the high working temperatures of the cell.
  • the achievement of the object according to the invention is characterized in that the mobile cover plates made of steel rest sealingly on the lower edge of the steel container and the two long sides of the carbon lining of the electrolysis bath in such a way that part of the cover plates in the longitudinal direction of the cell over the other part of the cover plates by hand is easy to move, and the top cover plates with their abutting forehead sides as well as the lower cover plates with the stationary terminal steel plates formed by magnetic forces formed by the electrolysis current butt joints.
  • the present invention ensures a highly effective encapsulation of the reduction cell by means of an improved arrangement of cover plates.
  • the plates can be easily moved by hand, which means that fewer plates are required, which in turn allows a corresponding reduction in the number of connections to be sealed.
  • the cover for the reduction cell is made of a material that withstands the working temperatures of the electrolysis without warping, bulging or other damage.
  • the slidable plates of the cover for the reduction cell can be easily moved back and forth by hand, which allows easy access for viewing and operating the cell.
  • These relatively large panels which can be easily moved by hand and which allow a reduced number of connections to be sealed, largely prevent emissions.
  • the plates are made of a material that resists the working temperatures of the cell, so that neither twisting nor bulging reduce the efficiency.
  • the reduction cell 10 comprises insulation material 12 which is inserted into a steel trough and which encases a coal trough 14.
  • the coal pan is the cathode of the reduction cell.
  • An electrical connection to the coal trough 14 is achieved by means of embedded cathode bars 16.
  • the coal pan 14 contains a bath 18 of molten metal which is formed by the reduction of alumina.
  • the molten electrolyte 20 is arranged on this metal bath 18.
  • the reduction cell 10 is provided with a large number of carbon anodes 22, which are immersed in the molten electrolyte 20.
  • the anodes 22 are suspended from anode rods 24 which are fastened to anode supports 26 by means of a clamping lock 28.
  • the clamping lock 28 ensures a good electrical connection of the anodes suspended from the anode rods to the anode carrier and also allows the height of each anode to be individually adjusted.
  • Any suitable means not shown, e.g. Screw thread, can be used for lifting and lowering the anode carrier 26 and thus the anode 22.
  • a funnel-shaped container 30 made of steel is arranged above the reduction cell 10 and fastened to rails 32 by any suitable means, which in turn are connected to a carrier 34 for fastening the funnel-shaped container 30 above the reduction cell 10.
  • the funnel-shaped container 30 is provided with a lower edge 36 designed as a supporting surface, which is arranged below the anode carrier and is rigidly attached to the container 30 or is formed integrally therewith, for reasons which will be explained in detail later.
  • the funnel-shaped container 30 is used for alumina delivery to the cell through an opening 38.
  • Channels 40 are arranged on both sides of the container opening 38 and are used to withdraw the anode gases developed during the electrolysis process.
  • the lower edge 36 which is designed as an aerofoil, is rigidly attached to the funnel-shaped container 30 and arranged under the movable anode carriers 26 in such a way that it extends over the entire area between the stationary cover plates 42.
  • the lower edge 36 which is designed as a supporting surface, is provided with numerous notched reinforcements which are penetrated by the anode rods 24.
  • rollers 46 and 46 ' On the lower edge 36, which is also made of steel, between the anode rods 24, there are pairs of rollers 46 and 46 ', one roller being in a plane above the lower edge and the other roller being in a plane below the lower edge.
  • the axes of the pairs of rollers lie in a plane approximately perpendicular to the lower edge 36.
  • FIG steel profile 48 which extends the entire length of the cell and comprises an inner rail 50 and an outer rail 52.
  • Four steel plates 54, 56, 58 and 60 are arranged on each long side of the cell.
  • Two of the plates, 54 and 60 are provided on their underside with a pair of grooved rollers 62 which are fastened to the plates 54 and 60 by means of electrically insulating supports 63 and are adapted in such a way that they can roll on the inner rail 50 of the profile 48 .
  • an aluminum angle profile 64 is fastened to the upper end of the steel plates 54 and 60, which is designed in such a way that it is fastened to the lower rollers 46 ', which are fastened to the lower edge 36 of the funnel-shaped container 30, which is designed as a supporting surface, can slide.
  • the steel plates 56 and 58 are, as described in relation to the plates 54 and 60, provided with grooved rollers 62 which are designed in such a way that they fit on the outer rail 52 of the profile 48.
  • an aluminum angle profile 66 is fastened to each upper end of the plates 56 and 58, which can be moved on the upper rollers 46 fastened to the lower edge 36 of the funnel-shaped container 30 designed as a supporting surface.
  • a handle 68 is provided on the plates 54 and 60 in the direction of the cell exterior, while two handles 68 are arranged on the plates 56 and 58.
  • the outer plate 58 is terminated with a flexible sealing material 70, e.g. Silicon rubber or a fabric made of silicon fibers.
  • the flexible seals on the outer plates 56 and 58 lie sealingly on the inner plates 54 and 60.
  • the inner plates 54 and 60 are provided with a flange component 72, on which a second flexible seal 74, which is fastened to the outer plates 56 and 58, rests.
  • the lower end angles of the plates 54, 56, 58 and 60, on which the grooving rollers 62 are fastened are provided with additional flexible sealing material 76, which is fastened on these angles and sealingly on the relevant inner and outer rails 50 and 52 of the profile 48 rests.
  • the present invention provides a highly effective cover for an aluminum reduction cell, in which an improved arrangement of cover plates, which are easily displaceable by hand, is used. This makes it possible to use a smaller number of plates, which is expressed in a corresponding reduction in the number of seals which have to seal off the interspaces. Furthermore, the covering hood according to the invention for an aluminum reduction cell made of steel, which can withstand the working temperatures of the electrolysis process without twisting, bulging or other damage to the plates, can be produced.

Abstract

The present invention provides a highly efficient reduction cell hood which utilizes an improved shield installation which is easily movable by hand thereby allowing for fewer shields which results in a corresponding decrease in the number of joints which must be sealed. The reduction cell hood of the present invention is constructed of a material which is capable of withstanding the operating temperatures of the electrolyte process without warping, buckling or other damage thereto.

Description

Die vorliegende Erfindung bezieht sich auf eine Abdeckhaube für eine im Schmelzfluss arbeitende Aluminiumreduktionszelle, mit einer das abgeschiedene flüssige Metall und den Elektrolyten enthaltenden Wanne und mehreren in den schmelzflüssigen Elektrolyten eingetauchten Kohleanoden, wobei die Abdeckhaube einen den Bereich zwischen den beiden Anodenträgesseiten abdeckenden Behälter mit einem als Tragfläche ausgebildeten unteren Rand und mehrere von diesem Rand über die gesamte Längsrichtung der Zelle bis zum Bord der Elektrolysewanne schräg abfallende mobile Abdeckplatten umfasst.The present invention relates to a cover for an aluminum reduction cell operating in the melt flow, with a trough containing the separated liquid metal and the electrolyte and a plurality of carbon anodes immersed in the molten electrolyte, the cover covering a container covering the area between the two anode support sides with an as Wing formed lower edge and several of this edge over the entire longitudinal direction of the cell to the board of the electrolysis tub sloping mobile cover plates.

Bei der elektrolytischen Herstellung von Aluminium wird eine Reduktionszelle verwendet. Die gegenwärtig in industriellen Verfahren eingesetzten Reduktionszellen variieren sowohl in bezug auf den Typ als auch auf die Grösse stark. Die meisten verwendeten Zellen können unter eine der folgenden Hauptkategorien eingeordnet werden:

  • - Soederbergöfen mit selbstbackenden Anoden, welche mit horizontalen oder vertikalen Kontaktspiessen ausgerüstet sind,
  • - Oefen mit vorgebrannten Anoden, welche seiten- oder mittelbedient sind.
A reduction cell is used in the electrolytic production of aluminum. The reduction cells currently used in industrial processes vary greatly in both type and size. Most of the cells used can be classified under one of the following main categories:
  • - Soederberg ovens with self-baking anodes, which are equipped with horizontal or vertical contact skewers,
  • - Furnaces with pre-burned anodes, which are operated from the side or medium.

Die Elektrolysezellen arbeiten mit Stromstärken von 45-225 kA (Kiloamperes). Typische Aluminiumreduktionszellen umfassen eine Kohlewanne, welche von Isoliermaterial umgeben ist. Der Boden der Kohlewanne ist mit eingebetteten Stahlbarren versehen, durch welche der Elektrolysestrom abfliesst, die Wanne wirkt als Kathode der Reduktionszelle. Die Wanne wird teilweise mit einem Aluminiumbad gefüllt, auf welchem der im wesentlichen geschmolzenen Kryolith (Na3AIF6) und darin gelöste Tonerde (AI203) umfassende Elektrolyt liegt. Eine oder mehrere Kohleanoden sind in den geschmolzenen Elektrolyten eingetaucht. Beim Durchgang des Gleichstroms von den Kohleanoden zum flüssigen Aluminium wird das im Elektrolyten gelöste AI203 dissoziiert. Im Verlauf des Elektrolyseverfahrens werden in der Reduktionszelle verschiedene Gase, wie Kohlenmonoxid und Kohlendioxid, und feindisperse Phasen, wie z.B. metallisches Natrium, gebildet. Im heutigen Zeitalter des Umweltbewusstseins sind zahlreiche Entwiklungen zum Auffangen und zur Behandlung der oben erwähnten Emissionen gemacht worden. In den letzten Jahren sind hochwirksame Behandlungssysteme entwickelt worden, wie z.B. die Vorrichtung der US-PS 3 470 075.The electrolysis cells work with currents of 45-225 kA (kiloamperes). Typical aluminum reduction cells include a coal pan surrounded by insulating material. The bottom of the coal trough is provided with embedded steel bars through which the electrolysis current flows, the trough acts as the cathode of the reduction cell. The tub is partially filled with an aluminum bath on which the essentially melted cryolite (Na 3 AIF 6 ) and clay (AI 2 0 3 ) dissolved therein contains electrolyte. One or more carbon anodes are immersed in the molten electrolyte. During the passage of the direct current from the carbon anodes to the liquid aluminum, the Al 2 0 3 dissolved in the electrolyte is dissociated. In the course of the electrolysis process, various gases, such as carbon monoxide and carbon dioxide, and finely dispersed phases, such as, for example, metallic sodium, are formed in the reduction cell. In today's era of environmental awareness, numerous developments have been made to capture and treat the emissions mentioned above. Highly effective treatment systems have been developed in recent years, such as the device of U.S. Patent 3,470,075.

Gegenwärtig liegt das grösste Problem für die weitere Verminderung oder Ausschaltung von beim Elektrolyseprozess erzeugten Emissionen bei der Konzeption einer wirksamen Abdeckhaube für das Auffangen der Gase, welche auf der Reduktionszelle angebracht werden kann. Bekannte Abdeckhauben, insbesondere solche für einen mittelbedienten Ofen, weisen den Nachteil auf, dass sie nicht genügend dicht sind, um das Entweichen eines merklichen Prozentgehaltes von umweltschädigenden Emissionen zu verhindern. Dies führt dazu, dass-obwohl aus dem Inneren der Abdeckhaube abgezogene Emissionen in hochwirksame Reinigungsanlagen überführt werden-ein merklicher Prozentanteil von Emissionen aus der Abdeckhaube entweicht und nie behandelt wird.Currently, the biggest problem for the further reduction or elimination of emissions generated during the electrolysis process lies in the design of an effective cover for collecting the gases, which can be attached to the reduction cell. Known cover hoods, in particular those for a medium-operated oven, have the disadvantage that they are not sufficiently tight to prevent a noticeable percentage of environmentally harmful emissions from escaping. As a result, although emissions extracted from inside the cover are transferred to highly effective cleaning systems, a noticeable percentage of emissions from the cover escapes and is never treated.

Die US-PS 3 948 749 zeigt eine typische Anordnung einer Abdeckhaube. In dieser Patentschrift wird eine übliche Haube gezeigt, welche eine Vielzahl von Platten aufweist, deren Grösse und Gewicht eine bequemes und leichtes Entfernen von Hand ermöglichen soll, sodass ein problemloser Zugang für das Besichtigen und die Bedienung der Zelle gewährleistet ist. Dieses Erfordernis leichter, von Hand entfernbarer Platten bedingt, dass eine grosse Anzahl von Platten eingesetzt werden muss, um die Reduktionszelle zu kapseln, was eine entsprechende Erhöhung der Anzahl von abzudichtenden Flächen und abzudichtenden Verbindungen zur Folge hat. Zusätzlich werden die Platten bezeichnenderweise aus leichtem Aluminium oder Aluminiumlegierungen hergestellt, um die Einwirkung der hohen Magnetfolder, welche mit Stahlplatten auftreten würden, zu mildern, weil diese Magnetfelder die zum Entfernen der Platten aufzuwendende Kraft erhöhen würden. Beim Einsatz von Aluminium kann deshalb das Gewicht der Platten beträchtlich erniedrigt werden.U.S. Patent 3,948,749 shows a typical hood arrangement. This patent shows a conventional hood, which has a large number of plates, the size and weight of which is intended to enable convenient and easy removal by hand, so that easy access is ensured for viewing and operating the cell. This requirement for lighter, hand-removable plates means that a large number of plates must be used to encapsulate the reduction cell, which results in a corresponding increase in the number of surfaces to be sealed and connections to be sealed. In addition, the plates are typically made of light aluminum or aluminum alloys to mitigate the effects of the high magnetic folders that would occur with steel plates, because these magnetic fields would increase the force required to remove the plates. When using aluminum, the weight of the plates can therefore be considerably reduced.

Es ist jedoch gefunden worden, dass die Verwendung von Abdeckplatten aus Aluminium im allgemeinen nicht wünschenswert ist. Der Schmelzpunkt von Aluminiumplatten liegt unterhalb der Arbeitstemperatur der Reduktionszelle. Diese führt häufig zu einem Verziehen der Platten, was sowohl einen Verlust an Wirksamkeit der Kapselung als auch eine entsprechende Erhöhung der Unterhaltskosten zur Folge hat.However, it has been found that the use of aluminum cover plates is generally undesirable. The melting point of aluminum plates is below the working temperature of the reduction cell. This often leads to warping of the plates, which results in both a loss in the effectiveness of the encapsulation and a corresponding increase in maintenance costs.

Die Erfinder haben sich deshalb die Aufgabe gestellt, eine Abdeckhaube für eine im Schmelzfluss arbeitende Aluminiumzelle zu schaffen, welche einen hohen Wirkungsgrad für das Einsammeln der Gase aufweist, von Hand leicht entfernt werden kann und von den hohen Arbeitstemperaturen der Zelle nicht beschädigt wird.The inventors have therefore set themselves the task of creating a cover for an aluminum cell working in the melt flow, which has a high efficiency for collecting the gases, can be easily removed by hand and is not damaged by the high working temperatures of the cell.

Die erfindungsgemässe Lösung der Aufgabe ist dadurch gekennzeichnet, dass die mobilen Abdeckplatten aus Stahl auf dem unteren Rand des Behälters aus Stahl und den beiden Längsseiten der Kohleauskleidung der Elektrolysewanne dichtend derart aufliegen, dass eine Teil der Abdeckplatten in Zellenlängsrichtung über den andern Teil der Abdeckplatten von Hand leicht verschiebbar ist, und die oberen Abdeckplatten mit ihren aneinanderliegenden Stirnseiten sowie die unteren Abdeckplatten mit den ortsfesten endständigen Stahlplatten durch vom Elektrolysestrom gebildete magnetische Kräfte susammengehaltene Stossverbindungen bilden.The achievement of the object according to the invention is characterized in that the mobile cover plates made of steel rest sealingly on the lower edge of the steel container and the two long sides of the carbon lining of the electrolysis bath in such a way that part of the cover plates in the longitudinal direction of the cell over the other part of the cover plates by hand is easy to move, and the top cover plates with their abutting forehead sides as well as the lower cover plates with the stationary terminal steel plates formed by magnetic forces formed by the electrolysis current butt joints.

Die vorliegende Erfindung gewährleistet mittels einer verbesserten Anordnung von Abdeckplatten eine hochwirksame Kapselung der Reduktionszelle. Die Platten können leicht von Hand bewegt werden, wodurch weniger Platten notwendig sind, was wiederum eine entsprechende Erniederung der Anzahl von abzudichtenden Verbindungen erlaubt. Die Abdeckhaube für die Reduktionszelle ist aus einem Material hergestellt, welches den Arbeitstemperaturen der Elektrolyse ohne Verwindungen, Verbeulungen oder anderen Schäden wiedersteht.The present invention ensures a highly effective encapsulation of the reduction cell by means of an improved arrangement of cover plates. The plates can be easily moved by hand, which means that fewer plates are required, which in turn allows a corresponding reduction in the number of connections to be sealed. The cover for the reduction cell is made of a material that withstands the working temperatures of the electrolysis without warping, bulging or other damage.

Die übereinanderschiebbaren Platten der Abdeckhaube für die Reduktionszelle können leicht von Hand hin- und hergeschoben werden, was einen leichten Zugang für die Besichtigung und die Bedienung der Zelle erlaubt. Diese leicht von Hand verschiebbaren, verhältnismässig grossen Platten, welche eine verminderte Anzahl von abzudichtenden Verbindungen erlauben, verhindern Emissionen weitgehend. Ueberdies sind die platten, weil diese leicht von Hand bewegbar sind, aus einem Material Hergestellt, welches den Arbeitstemperaturen der Zelle widersteht, sodass weder Verwindungen noch Verbeulungen eine Verminderung des Wirkungsgrades herbeiführen.The slidable plates of the cover for the reduction cell can be easily moved back and forth by hand, which allows easy access for viewing and operating the cell. These relatively large panels, which can be easily moved by hand and which allow a reduced number of connections to be sealed, largely prevent emissions. In addition, because they are easy to move by hand, the plates are made of a material that resists the working temperatures of the cell, so that neither twisting nor bulging reduce the efficiency.

Damit können dank der vorliegenden Erfindung die vorher bekannten Nachteile von Abdeckhauben für Reduktionszellen überwunden werden.Thanks to the present invention, the previously known disadvantages of covers for reduction cells can thus be overcome.

Die Erfindung wird anhand der Zeichung näher erläutert. Es zeigen schematisch:

  • - Fig. 1 eine perspektivische Ansicht einer Aluminiumreduktionszelle, welche die Anordnung der verschiebbaren Platten der Abdeckhaube veranschlaulicht
  • - Fig. 2 einen vertikalen Querschnitt dirch die in Fig. 1 gezeigte Aluminiumreduktionszelle
  • - Fig. 3 eine teilweise perspektivische Seitenansicht der Reduktionszelle von Fig. 1 mit übereinandergeschobenen Abdeckplatten.
  • - Fig. 4 eine vergrösserte perspektivische Seitenansicht eines Details der verschiebbaren Abdeckplatten.
The invention is explained in more detail with reference to the drawing. They show schematically:
  • - Fig. 1 is a perspective view of an aluminum reduction cell, the arrangement of the slidable plates of the cover hatchlaulicht
  • FIG. 2 is a vertical cross section through the aluminum reduction cell shown in FIG. 1
  • 3 shows a partial perspective side view of the reduction cell from FIG. 1 with cover plates pushed one on top of the other.
  • 4 is an enlarged perspective side view of a detail of the sliding cover plates.

Die Reduktionszelle 10 umfasst in eine Stahlwanne eingelegtes Isolationsmaterial 12, welches eine Kohlenwanne 14 umhüllt. Die Kohlewanne ist die Kathode der Reduktionszelle. Eine elektrische Verbindung zu der Kohlewanne 14 wird mittels eingebetteter Kathodenbarren 16 erreicht. Die Kohlewanne 14 enthält ein Bad 18 von geschmolzenem Metall, welches durch Reduktion von Tonerde gebildet wird. Auf diesem Metallbad 18 ist der schmelzflüssige Elektrolyt 20 angeordnet.The reduction cell 10 comprises insulation material 12 which is inserted into a steel trough and which encases a coal trough 14. The coal pan is the cathode of the reduction cell. An electrical connection to the coal trough 14 is achieved by means of embedded cathode bars 16. The coal pan 14 contains a bath 18 of molten metal which is formed by the reduction of alumina. The molten electrolyte 20 is arranged on this metal bath 18.

Die Reduktionszelle 10 ist mit einer Vielzahl von Kohleanoden 22 versehen, welche in den schmelzflüssigen Elektrolyten 20 eintauchen. Die Anoden 22 sind an Anodenstangen 24 aufgehängt, welche mittels eines Klemmschlosses 28 an Anodenträgern 26 befestigt sind. Das Klemmschloss 28 gewährleistet eine gute elektrische Verbindung der an den Anodenstangen aufgehängten Anoden mit dem Anodenträger und erlaubt überdies ein individuelles Einstellen der Höhe von jeder Anode. Jedes geeignete, nicht dargestellte Mittel, wie z.B. Schraubengewinde, kann für das Heben und Senken der Anodenträger 26 und damit der Anoden 22 verwendet werden. Ueber der Reduktionszelle 10 ist ein trichterförmiger Behälter 30 aus Stahl angeordnet und mit irgend einem geeigneten Mittel an Schienen 32 befestigt, die ihrerseits zum Befestigen des trichterförmigen Behälters 30 über der Reduktionszelle 10 mit einem Träger 34 verbunden sind. Der trichterförmige Behälter 30 ist mit einem als Tragfläche ausgebildeten unteren Rand 36 versehen, welcher unterhalb des Anodenträgers angeordnet und starr am Behälter 30 befestigt oder einstückig damit ausgebildet ist, aus Gründen die später im Detail erläutert werden. Der trichterförmige Behälter 30 wird für die Tonerdezufuhr zu der Zelle durch eine Oeffnung 38 verwendet. Beidseits der Behälteröffnung 38 sind Kanäle 40 angeordnet, welche zum Abziehen der während des Elektrolyseverfahrens entwickelten Anodengase dienen.The reduction cell 10 is provided with a large number of carbon anodes 22, which are immersed in the molten electrolyte 20. The anodes 22 are suspended from anode rods 24 which are fastened to anode supports 26 by means of a clamping lock 28. The clamping lock 28 ensures a good electrical connection of the anodes suspended from the anode rods to the anode carrier and also allows the height of each anode to be individually adjusted. Any suitable means not shown, e.g. Screw thread, can be used for lifting and lowering the anode carrier 26 and thus the anode 22. A funnel-shaped container 30 made of steel is arranged above the reduction cell 10 and fastened to rails 32 by any suitable means, which in turn are connected to a carrier 34 for fastening the funnel-shaped container 30 above the reduction cell 10. The funnel-shaped container 30 is provided with a lower edge 36 designed as a supporting surface, which is arranged below the anode carrier and is rigidly attached to the container 30 or is formed integrally therewith, for reasons which will be explained in detail later. The funnel-shaped container 30 is used for alumina delivery to the cell through an opening 38. Channels 40 are arranged on both sides of the container opening 38 and are used to withdraw the anode gases developed during the electrolysis process.

Die obenstehende Beschreibung dient dazu, die allgemeine Bauweise der Aluminiumreduktionszelle zu zeigen, damit der Aufbau der erfindungsgemässen Abdeckhaube erläutert werden kann.The above description serves to show the general construction of the aluminum reduction cell, so that the structure of the cover according to the invention can be explained.

An den stirnförmigen Enden der Kohlewanne 12 werden Stahlplatten 42 mit als hochklappbare Besichtigungstüren ausgebildeten Schrägflächen 44 ortsfest angeordnet. Der als Tragfläche ausgebildete untere Rand 36 wird starr am trichterförmigen Behälter 30 befestigt und unter den bewegbaren Anodenträgern 26 so angeordnet, dass er sich über den ganzen Bereich zwischen den ortsfesten Abdeckplatten 42 erstreckt. Wie am besten aus Figur 3 ersehen werden kann, ist der als Tragfläche ausgebildete untere Rand 36 mit zahlreichen eingekerbten Verteifungen versehen, welche von den Anodenstangen 24 durchgriffen werden. Auf dem auch aus Stahl bestehenden unteren Rand 36, zwischen der Anodenstangen 24, befinden sich Rollenpaare 46 und 46', wobei sich die einen Rollen in einer Ebene oberhalb des unteren Randes, und die andern Rollen in einer Ebene unterhalb des unteren Randes befinden. Die Achsen der Rollenpaare liegen in einer ungefähr zum unteren Rand 36 senkrechten Ebene.At the end-shaped ends of the coal trough 12, steel plates 42 with inclined surfaces 44 designed as flip-up inspection doors are arranged in a stationary manner. The lower edge 36, which is designed as an aerofoil, is rigidly attached to the funnel-shaped container 30 and arranged under the movable anode carriers 26 in such a way that it extends over the entire area between the stationary cover plates 42. As can best be seen from FIG. 3, the lower edge 36, which is designed as a supporting surface, is provided with numerous notched reinforcements which are penetrated by the anode rods 24. On the lower edge 36, which is also made of steel, between the anode rods 24, there are pairs of rollers 46 and 46 ', one roller being in a plane above the lower edge and the other roller being in a plane below the lower edge. The axes of the pairs of rollers lie in a plane approximately perpendicular to the lower edge 36.

Auf beiden Längsseiten der Kathodenwanne 14 der Reduktionszelle 10, über den ganzen Bereich zwischen den endständigen ortsfesten Abdeckplatten 42, ist-wie am besten aus Fig. 4 ersehen werden kann-ein sich über die ganze Zellenlänge erstreckendes Stahlprofil 48, welches eine innere Schiene 50 und eine äussere Schiene 52 umfasst, montiert. Auf jeder Längsseite der Zelle sind vier Stahlplatten 54, 56, 58 und 60 angeordnet. Zwei der Platten, 54 und 60, sind auf ihrer Unterseite mit einem Paar von Nutrollen 62 versehen, welche auf den Platten 54 und 60 mittels elektrisch isolierender Träger 63 befestigt und derart angepasst sind, dass sie auf der inneren Schiene 50 des Profils 48 rollen können. Fig. 2 zeigt, dass am oberen Ende der Stahlplatten 54 und 60 je ein Aluminiumwinkelprofil 64 befestigt ist, welches derart gestaltet ist, dass es auf den unteren Rollen 46', welche am als Tragfläche ausgebildeten unteren Rand 36 des trichterförmigen Behälters 30 befestigt sind, gleiten kann. Die Stahlplatten 56 und 58 sind, wie in bezug auf die Platten 54 und 60 beschrieben, mit Nutrollen 62 versehen, welche derart gestaltet sind, dass sie auf die äussere Schiene 52 des Profils 48 passen. Ebenso ist an jedem oberen Ende der Platten 56 und 58 je ein Aluminiumwinkelprofil 66 befestigt, welches auf den oberen, am als Tragfläche ausgebildeten unteren Rand 36 des trichterförmigen Behälters 30 befestigten Rollen 46 verschoben werden kann.On both long sides of the cathode tub 14 of the reduction cell 10, over the entire area between the terminal stationary cover plates 42, there is - as can best be seen from FIG steel profile 48 which extends the entire length of the cell and comprises an inner rail 50 and an outer rail 52. Four steel plates 54, 56, 58 and 60 are arranged on each long side of the cell. Two of the plates, 54 and 60, are provided on their underside with a pair of grooved rollers 62 which are fastened to the plates 54 and 60 by means of electrically insulating supports 63 and are adapted in such a way that they can roll on the inner rail 50 of the profile 48 . 2 shows that an aluminum angle profile 64 is fastened to the upper end of the steel plates 54 and 60, which is designed in such a way that it is fastened to the lower rollers 46 ', which are fastened to the lower edge 36 of the funnel-shaped container 30, which is designed as a supporting surface, can slide. The steel plates 56 and 58 are, as described in relation to the plates 54 and 60, provided with grooved rollers 62 which are designed in such a way that they fit on the outer rail 52 of the profile 48. Likewise, an aluminum angle profile 66 is fastened to each upper end of the plates 56 and 58, which can be moved on the upper rollers 46 fastened to the lower edge 36 of the funnel-shaped container 30 designed as a supporting surface.

Auf den Platten 54 und 60 ist in Richtung der Zellenaussenseite je ein Handgriff 68 vorgesehen, während auf den Platten 56 und 58 je zwei Handgriffe 68 angeordnet sind.A handle 68 is provided on the plates 54 and 60 in the direction of the cell exterior, while two handles 68 are arranged on the plates 56 and 58.

Unabhängig von der Grösse der Reduktionszelle müssen auf jeder Zellenlängsseite nur je vier Abdeckplatten 54, 56, 58 und 60 angeordnet werden. Weil die Platten für die Zellenbedienung seitwärts verschoben werden und nicht von Hand entfernt werden müssen, spielt das Gewicht der Platten nur eine geringe Rolle. Weiter haben die Magnetfelder zwischen den Plattenweil diese nicht von der Zelle entfernt werden müssen, sondern nur seitwärts gerollt werden können-und der Zelle während des Verschiebens nur einen geringen Einfluss, weshalb die Platten aus einer schweren und starken Stahlkonstruktion bestehen könne. Die Anordnung von zwei inneren Platten 54 und 60 und zwei äusseren Platten 56 und 58 erlaubt, dass bis zu 50% jeder Längsseite der Reduktionszelle jederzeit für die Bedienung freigelegt werden können.Regardless of the size of the reduction cell, only four cover plates 54, 56, 58 and 60 have to be arranged on each longitudinal side of the cell. Because the plates for cell operation are moved sideways and do not have to be removed by hand, the weight of the plates plays only a minor role. Furthermore, the magnetic fields between the plates do not have to be removed from the cell, but can only be rolled sideways - and have only a slight influence on the cell during displacement, which is why the plates can be made of a heavy and strong steel structure. The arrangement of two inner plates 54 and 60 and two outer plates 56 and 58 allows up to 50% of each long side of the reduction cell to be exposed for operation at any time.

Die übereinanderschiebbare Anordnung der inneren und äusseren Platten, z.B. 58 und 60, erlaubt, wie in Fig. 4 dargestellt, eine problemlose Dichtverbindung. Die äussere Platte 58 ist an deren Ende mit einem flexiblen Dichtungsmaterial 70, wie z.B. Siliziumgummi oder einem Gewebe aus Siliziumfibern versehen. Die flexiblen Dichtungen auf den äussern Platten 56 bzw. 58 liegen dichtend auf den inneren Platten 54 und 60 auf. Zusätzlich sind die inneren Platten 54 und 60 mit einem Flanschbauteil 72 versehen, auf welchem eine zweite flexible Dichtung 74, die an den äussern Platten 56 und 58 befestigt ist, aufliegt. Weiter sind die unteren Abschlusswinkel der Platten 54, 56, 58 und 60, auf welchen die Nutrollen 62 befestigt sind, mit zusätzlichen flexiblem Dichtungsmaterial 76 versehen, welches auf diesen Winkeln befestigt ist und dichtend auf der betreffenden inneren und äusseren Schiene 50 und 52 des Profils 48 aufliegt. Daraus kann ersehen werden, dass die seitlich verschiebbaren Platten der erfindungsgemässen Abdeckhaube sowohl an inren überlappenden Verbindungen als auch gegenüber dem die inneren und äusseren Schienen bildenden Profil 48 wirkungsvoll agbedichtet sind.The stackable arrangement of the inner and outer panels, e.g. 58 and 60, as shown in Fig. 4, allows a problem-free sealing connection. The outer plate 58 is terminated with a flexible sealing material 70, e.g. Silicon rubber or a fabric made of silicon fibers. The flexible seals on the outer plates 56 and 58 lie sealingly on the inner plates 54 and 60. In addition, the inner plates 54 and 60 are provided with a flange component 72, on which a second flexible seal 74, which is fastened to the outer plates 56 and 58, rests. Furthermore, the lower end angles of the plates 54, 56, 58 and 60, on which the grooving rollers 62 are fastened, are provided with additional flexible sealing material 76, which is fastened on these angles and sealingly on the relevant inner and outer rails 50 and 52 of the profile 48 rests. It can be seen from this that the laterally displaceable plates of the covering hood according to the invention are effectively ag-sealed both at their internal overlapping connections and against the profile 48 which forms the inner and outer rails.

Die Stossverbindung zwischen den äusseren Platten 56 und 58 und die Stossverbindungen zwischen den inneren Platten 54 und 60 und den ortsfesten endständigen Stahlplatten 42 werden durch den in den Stahlplatten erzeugten Magnetfeldeffekt undurchlässig abgedichtet. Schliesslich sollte noch erwähnt werden, dass die Kraft der metallischen Anziehung zwischen den Platten der oben erwähnten Stossverbindungen dadurch eingestellt werden kann, dass ein kontinuierlicher dünner Streifen-welcher in der Zeichnung nicht dargestellt ist-von nicht magnetischem Material, wie z.B. Aluminium, Messing oder rostfreiem Stahl, zwischen den Stossverbindungen angebracht wird. Dadurch ist die Anziehungskraft zwischen den eine Stossverbindung bildenden Platten genügend stark, um eine undurchlässige Dichtung zu bilden, aber nicht zu stark, um ein Trennen der beiden Platten durch ein menschliches Individuum zu verhindern.The butt joint between the outer plates 56 and 58 and the butt joint between the inner plates 54 and 60 and the stationary terminal steel plates 42 are sealed impermeably by the magnetic field effect generated in the steel plates. Finally, it should be mentioned that the force of the metallic attraction between the plates of the abovementioned butt joints can be adjusted by using a continuous thin strip - which is not shown in the drawing - of non-magnetic material, e.g. Aluminum, brass or stainless steel, is placed between the butt joints. As a result, the force of attraction between the butt joint plates is sufficiently strong to form an impermeable seal, but not too strong to prevent separation of the two plates by a human individual.

Aus dieser Beschreibung ist ersichtlich, dass die vorliegende Erfindung eine hochwirksame Abdeckhaube für eine Aluminiumreduktionszelle zur Verfüngung stellt, bei welcher eine verbesserte Anordnung von Abdeckplatten, welche leicht von Hand verschiebbar sind, verwendet wird. Dadurch wird es möglich, eine geringere Anzahl von Platten einzusetzen, was sich in einer entsprechenden Verminderung der Anzahl von Dichtungen, welche die Zwischenräume undurchlässig abschliessen müssen, ausdrückt. Weiter kann die erfindungsgemässe Abdeckhaube für eine Aluminiumreduktionszelle aus Stahl, welche den Arbeitstemperaturen des Elektrolyseverfahrens ohne Verwindungen, Verbeulungen oder andere Beschädigungen der Platten widerstehen kann, hergestellt werden.From this description it can be seen that the present invention provides a highly effective cover for an aluminum reduction cell, in which an improved arrangement of cover plates, which are easily displaceable by hand, is used. This makes it possible to use a smaller number of plates, which is expressed in a corresponding reduction in the number of seals which have to seal off the interspaces. Furthermore, the covering hood according to the invention for an aluminum reduction cell made of steel, which can withstand the working temperatures of the electrolysis process without twisting, bulging or other damage to the plates, can be produced.

Claims (4)

1. Cover hood for an aluminium reduction cell working in the state of fusion, having a vessel (14) containing the separated liquid metal (18) and the electrolyte (20) and several carbon anodes (22) dipping into the molten electrolyte, the cover hood comprising a container (30) covering the region between the two anode carrier rows (26) with a lower edge (36) formed as carrier surface and several mobile cover plates (54, 56, 58, 60) which slope obliquely from this edge over the entire longitudinal direction of the cell down to the rim of the electrolysis vessel, characterised in that the mobile cover plates (54, 56, 58, 60) of steel lie in sealing manner on the lower edge (36) of the steel container (30) and the two longitudinal sides of the carbon lining (14) of the electrolytic vessel, in such a way that one part of the cover plates (56, 58) is easily displaceable by hand in the longitudinal direction of the cell over the other part of the cover plates (54, 60), and the upper cover plates (56, 58) with their end sides lying against one another and the lower cover plates (54, 60) with the stationary end steel plates (42) form butt connections held together by magnetic forces formed from the electrolytic current.
2. Cover hood according to claim 1, characterised in that a continuous thin strip of nonmagnetic material is applied to the butt connections.
3. Cover hood according to claim 1 or 2, characterised in that four cover plates (54, 56, 58, 60) are arranged on each longitudinal side of the cell.
4. Cover hood according to one of claims 1 to 3, characterised in that the cover plates (54, 56, 58, 60) are displaceable by way of rollers (46, 46') arranged non-displaceably above and below the lower edge (36) of the container (30) and/or by means of rollers (62) arranged in electrically insulating manner in the lower region of the cover plates on an outer and an inner rail (50, 52) formed on the two longitudinal sides of the carbon lining (14) of the electrolysis vessel from the flanges of a section (48).
EP80810122A 1979-04-23 1980-04-11 Hood for an aluminium reduction cell Expired EP0018326B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80810122T ATE9233T1 (en) 1979-04-23 1980-04-11 COVER FOR AN ALUMINUM REDUCTION CELL.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US06/032,032 US4202753A (en) 1979-04-23 1979-04-23 Reduction cell hood
US32032 1979-04-23

Publications (2)

Publication Number Publication Date
EP0018326A1 EP0018326A1 (en) 1980-10-29
EP0018326B1 true EP0018326B1 (en) 1984-09-05

Family

ID=21862741

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80810122A Expired EP0018326B1 (en) 1979-04-23 1980-04-11 Hood for an aluminium reduction cell

Country Status (11)

Country Link
US (1) US4202753A (en)
EP (1) EP0018326B1 (en)
AT (1) ATE9233T1 (en)
BR (1) BR8002440A (en)
CA (1) CA1134778A (en)
DE (1) DE3069094D1 (en)
ES (1) ES489499A0 (en)
GR (1) GR67733B (en)
NO (1) NO154526C (en)
YU (1) YU110580A (en)
ZA (1) ZA802281B (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4394242A (en) * 1980-01-28 1983-07-19 Adnovum Ag Clamp, tool, and electrolysis cell anode mount
CH647007A5 (en) * 1981-05-20 1984-12-28 Alusuisse ANODE FOR A MELTFLOW ELECTROLYSIS CELL.
US20040000491A1 (en) * 2002-06-28 2004-01-01 Applied Materials, Inc. Electroplating cell with copper acid correction module for substrate interconnect formation
US20040026255A1 (en) * 2002-08-06 2004-02-12 Applied Materials, Inc Insoluble anode loop in copper electrodeposition cell for interconnect formation
FR2879582B1 (en) * 2004-12-21 2007-01-19 Ecl Soc Par Actions Simplifiee DEVICE FOR HANDLING THE HOODS OF A CELL FOR THE PRODUCTION OF ALUMINUM BY ELECTROLYSIS
NO328467B1 (en) * 2005-12-09 2010-02-22 Norsk Hydro As Method and apparatus for encapsulating an electrolysis cell
FR3012473A1 (en) * 2013-10-30 2015-05-01 Rio Tinto Alcan Int Ltd SEALING DEVICE FOR ELECTROLYSIS CELL HOOD
AU2015349579B2 (en) * 2014-11-21 2020-10-01 Hatch Ltd. Low-profile aluminum cell potshell and method for increasing the production capacity of an aluminum cell potline
CN112176365B (en) * 2020-09-15 2023-06-23 包秀锋 Novel engineering plastic anode cover and anode frame for metallurgical industry
EP4174216A1 (en) * 2021-10-27 2023-05-03 Dubai Aluminium PJSC Protection device for anodes of an electrolytic cell, comprising movable panels, and its implementation method

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU134429A1 (en) * 1960-04-18 1960-11-30 Г.Г. Величко Shelter for Aluminum Electrolyzers
CH568403A5 (en) * 1971-11-18 1975-10-31 Alusuisse
SU393361A1 (en) * 1972-01-10 1973-08-10 Иркутский алюминиевый завод
DE2263348A1 (en) * 1972-12-23 1974-07-04 Siemag Translift Gmbh Aluminium electrolysis plant operating in fused salts - has segmented half hoods with individual drive for telescopic contraction
DE2330557B2 (en) * 1973-06-15 1976-09-16 Wolgogradskij Aljuminiewyj Sawod, Wolgograd (Sowjetunion) COVER OF AN ELECTROLYSIS CELL WITH PRE-FIRED ELECTRODES FOR THE EXTRACTION OF ALUMINUM
AT329892B (en) * 1973-09-28 1976-06-10 Vmw Ranshofen Berndorf Ag ALUMINUM ELECTROLYSIS CELL WITH COVER AND GAS EXTRACTION DEVICE
US4136003A (en) * 1975-03-10 1979-01-23 Swiss Aluminum Ltd. Cell for fused-salt electrolysis with gas collecting means
DE2510400C2 (en) * 1975-03-10 1985-08-08 Schweizerische Aluminium Ag, Chippis Melt flow electrolysis cell
US3948749A (en) * 1975-04-02 1976-04-06 Copperloy Corporation Aluminum potline shield
US4002551A (en) * 1975-04-17 1977-01-11 Aluminium Pechiney Process and apparatus for collecting the fumes given off during the production of aluminium in an electrolysis cell with a continuous anode
US4043892A (en) * 1975-12-15 1977-08-23 Reynolds Metals Company Aluminum reduction cell having a lateral enclosure system

Also Published As

Publication number Publication date
NO154526C (en) 1986-10-08
ATE9233T1 (en) 1984-09-15
EP0018326A1 (en) 1980-10-29
DE3069094D1 (en) 1984-10-11
YU110580A (en) 1983-02-28
NO154526B (en) 1986-06-30
ES8103200A1 (en) 1981-02-16
ZA802281B (en) 1981-05-27
BR8002440A (en) 1980-12-02
ES489499A0 (en) 1981-02-16
US4202753A (en) 1980-05-13
CA1134778A (en) 1982-11-02
GR67733B (en) 1981-09-16
NO801140L (en) 1980-10-24

Similar Documents

Publication Publication Date Title
EP0018326B1 (en) Hood for an aluminium reduction cell
DE4118304A1 (en) ELECTROLYSIS CELL FOR ALUMINUM EFFICIENCY
DE2508129A1 (en) METHOD AND DEVICE FOR COLLECTING GAS FROM A TUB FOR PRODUCING ALUMINUM BY MELTING ELECTROLYSIS
DE19634348A1 (en) Melting unit with an electric arc furnace
EP0031307B1 (en) Device for conducting the current between electrolysis cells
DE2841459A1 (en) COVER OF A MELTFLOW ELECTROLYSIS CELL
DE1202988B (en) Aluminum electrolytic furnace
DE1239860B (en) Fused metal electrolysis furnace with prefired anodes
DE2220122A1 (en) Heater with removable heating elements and heat shields
DE3120580C1 (en) Anode for a molten-salt electrolysis cell
DE1188823B (en) Device for supplying current to the cathode of a furnace for the electrolytic production of aluminum and method for operating the device
DE3535690A1 (en) CONTACT ELECTRODE ARRANGEMENT FOR DC ARC OR RESISTANCE MELTING STOVE
DE2056127C3 (en) Device for electrophoresis
DE2731908C2 (en) Method and apparatus for producing aluminum
DE2251898C3 (en) Melt flow electrolysis cell with cover
DE2213226B2 (en) Electrolysis cell for the production of light metal
DE3640144C2 (en)
DE1148755B (en) Cell for fused salt electrolysis and process for the production of aluminum
DE2706811B2 (en) Electric resistance furnace
DE2128220C3 (en) Closed electrolytic cell
DE2413763C3 (en) Hood for an electrolysis furnace for the production of aluminum, which works with pre-burned anodes
DE2263349A1 (en) Aluminium furnace for electrolysis in fused salts - fitted with sectional hoods over bath each with own actuating cylinder
DE2510400C2 (en) Melt flow electrolysis cell
DD130680B1 (en) DEVICE FOR SEALING BETWEEN CHAMBER OVEN AND HERDWAGEN
AT163633B (en) Electrolytic cell

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT CH DE FR GB IT NL

17P Request for examination filed

Effective date: 19810129

ITF It: translation for a ep patent filed

Owner name: DE DOMINICIS & MAYER S.R.L.

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): AT CH DE FR GB IT LI NL

REF Corresponds to:

Ref document number: 9233

Country of ref document: AT

Date of ref document: 19840915

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3069094

Country of ref document: DE

Date of ref document: 19841011

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19881118

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19930319

Year of fee payment: 14

Ref country code: CH

Payment date: 19930319

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19930325

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19930326

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19930430

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19940411

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19940430

Ref country code: CH

Effective date: 19940430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19941101

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19941229

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19950103

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST