EP0241387B1 - Giessform, die die Regulierung der Höhe der freien Oberfläche von Metallschmelzen zur Berührung mit der Giessform beim vertikalen Giessen gestattet - Google Patents

Giessform, die die Regulierung der Höhe der freien Oberfläche von Metallschmelzen zur Berührung mit der Giessform beim vertikalen Giessen gestattet Download PDF

Info

Publication number
EP0241387B1
EP0241387B1 EP87420070A EP87420070A EP0241387B1 EP 0241387 B1 EP0241387 B1 EP 0241387B1 EP 87420070 A EP87420070 A EP 87420070A EP 87420070 A EP87420070 A EP 87420070A EP 0241387 B1 EP0241387 B1 EP 0241387B1
Authority
EP
European Patent Office
Prior art keywords
mould
metal
film
mould according
casting
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
EP87420070A
Other languages
English (en)
French (fr)
Other versions
EP0241387A1 (de
Inventor
Jean-Pierre Riquet
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.)
Cegedur Societe de Transformation de lAluminium Pechiney SA
Original Assignee
Cegedur Societe de Transformation de lAluminium Pechiney SA
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 Cegedur Societe de Transformation de lAluminium Pechiney SA filed Critical Cegedur Societe de Transformation de lAluminium Pechiney SA
Priority to AT87420070T priority Critical patent/ATE39332T1/de
Publication of EP0241387A1 publication Critical patent/EP0241387A1/de
Application granted granted Critical
Publication of EP0241387B1 publication Critical patent/EP0241387B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/059—Mould materials or platings

Definitions

  • the invention relates to an ingot mold for adjusting the level at which it is in contact with the free surface of the metal in a vertical casting.
  • French patent 1,398,526 teaches the use of a strip of fiberfrax bonded to the ingot mold so as to reduce the height of metal in contact with the ingot mold, and therefore to reduce the effects due to indirect cooling.
  • this reduction in height cannot be fixed once and for all, since it depends in particular on the speed of casting.
  • this parameter varies, it is necessary either to change the mold, or at least to modify the height of the strip. What confers a lack of flexibility to a solution bringing in the end only a partial suppression of heterogeneities.
  • HAT TOP loaded casting with enhancement
  • French patent 2,417,357 has claimed a process in which the axial length of the part of the ingot mold in contact with the molten metal is varied by putting into action a sleeve which slides on the inner wall of the ingot mold.
  • Such a system has the disadvantage during untimely solidification of the metal that it leads to adhesion between the ingot mold and the cuff, thus causing the parts present to be torn off when the sliding movement is carried out.
  • This means consists in applying to the liquid in the course of solidification a periodic magnetic field of variable intensity and direction substantially parallel to the axis of the ingot mold and of adapting its intensity as a function of the desired level.
  • the advantage of such a method is therefore to allow the metal-ingot contact height and consequently the thickness of the cortical layer to be reduced at will simply with a coil supplied by a current of industrial frequency 50 or 60 Hz knowing that any electrical failure will only have the effect of varying the height of metal in the ingot mold, that is to say that any risk of leakage of liquid metal will be eliminated, which is not the case in casting electromagnetic.
  • the presence of an ingot mold while limiting the possibility of oxidation of the liquid metal at the meniscus, prevents, by the contact it has with the metal, any displacement of the oxide film towards the side wall. and therefore any risk of tingling on the surface of the semi-finished product.
  • the field applied to the metal also has the effect of creating forces inside the liquid which homogenize the cooling and tend to cause a refinement of the pouring grain.
  • the solution consisting in surrounding the ingot mold by an annular coil if it has the great advantage of not modifying in any way the conventional assembly of the casting looms, it has on the other hand the disadvantage of entailing a significant consumption of energy electric.
  • the ingot mold absorbs part of the magnetic field representing approximately 15 to 30% of the total energy consumed.
  • the coil must be away from the liquid metal; however, as the intensity of the magnetic field decreases all the more as this distance is great, this results in an additional loss of energy.
  • an ingot mold characterized in that it consists at least in its lower part by a metal, that it is coated internally with a film of electrically insulating material, that it has, along at least one generator, over its entire height and over its entire thickness, an insert made of electrically insulating material, which it is provided externally at said lower part with two terminals placed on either side of said insert and connected to an alternating current source.
  • the ingot mold is constructed of metal and preferably a metal having a low electrical resistivity such as copper or aluminum and their alloys. This poses no problem since the ingot molds are traditionally made of such metals.
  • the mold it is not necessary for the mold to be entirely made of metal and it is even preferable to use composite molds in which the use of such a material is limited to the lower part and the upper part is provided with the flange with a material that is otherwise insulating, at least a poor conductor of electricity such as stainless steel, for example. Indeed, we will see later that by limiting the passage height of the current in the mold, we get better results.
  • the ingot mold according to the invention is characterized in particular in that it is coated internally with a film of electrically insulating material in order to avoid the passage of current from the ingot mold to the cast metal.
  • This film must completely cover the internal surface of the mold from the bottom up. It is desirable that this film is not a good thermal insulator because it would disturb the heat exchanges between mold and metal and would have unfortunate repercussions on the quality of the products obtained. This is why the applicant has been led to study this problem closely and has found after numerous tests that only certain films are applicable.
  • the ingot mold is made of aluminum or one of its alloys of an aluminum oxide film obtained by anodization.
  • this film whatever the type of anodization used, forms a continuous coating, relatively resistant to the passage of current, and good conductor of heat since thicknesses as small as 1 ⁇ .Lm allow the application of voltages close to 100 volts.
  • this type of coating is very resistant to abrasion, and can be impregnated with a lubricating agent (hot grease) to facilitate casting.
  • this oxide easily lends itself to coloring, which makes it possible to detect any deterioration of the coating being produced.
  • enamel film Another type of coating having the same advantages as oxide is the enamel film, the production of which makes use of techniques known to those skilled in the art.
  • Another interesting solution consists in separating the film from the cast metal with a layer of graphite a few millimeters thick, which also avoids the need for a lubricating agent.
  • the invention is also characterized in that the ingot mold has, according to at least one generator, over its entire height and over its entire thickness, an insert made of electrically insulating material. It is indeed necessary for the mold to perform a function similar to that of the coil, that it allows the current flowing through it to flow in a direction perpendicular to the axis of the mold. This is obtained by slitting the mold over its entire height, by inserting into this slot an electrical insulator and by supplying the mold with alternating current from two terminals placed on its outer wall on either side of said insert, and at the level of the metallic lower part.
  • This insulator can be any material known to those skilled in the art, such as mica for example, including the materials constituting the film and in particular in the case of an aluminum ingot mold or one of its alloys, oxide obtained by anodization; the two terminals for connection to the electrical network are of any known type.
  • FIG. 1 there is a supply nozzle (1) made of liquid metal, a stopper rod (2) for level regulation, an ingot mold (3) cooled directly by a fluid (4) which then cools the metal (5) directly at point (6).
  • the right half ingot mold is equipped with a coil (7) which is supplied with an alternating voltage (8) in order to create the magnetic field of direction (9) and to cause the lowering of the level of the contact line of the surface of the metal with the ingot mold of a point (10) in the casting of the prior art at point (11) according to the method, point which is located at the intersection (12) of the solidification front (13 ) resulting from indirect cooling and the front (14) resulting from direct cooling.
  • the contact height of the metal with the ingot mold has been reduced from a height h 1 to an extremely small height h 2 which can be assimilated to point (11).
  • an aluminum ingot mold (15) is seen internally coated with an oxide film (16) obtained by anodization having on one of its generators a slot (17) whose facing faces have also been anodized and two terminals (18) which are connected to a non-alternating current source represented.
  • a composite ingot mold is seen formed from an upper part (19) of stainless steel and a lower part (20) of aluminum.
  • the assembly is internally coated with a film (21) of fluorocarbon resin.
  • two terminals (22) connected to an alternating current source not shown.
  • the invention can be illustrated by means of the following application examples which compare, for 3 types of ingot molds, the intensity necessary to lower the level of the line of contact of the metal with the ingot mold respectively by 15, 30 and 40 mm in an aluminum ingot mold of section 1100 x 300 mm and in which the metal level in the center was fixed at 60 mm from the base of the ingot mold.
  • Type 1 although less efficient, nevertheless constitutes very significant progress compared to the ingot molds of the prior art since the intensity is practically divided by 2.
  • the present invention finds its application in the casting of metallurgical semi-products, in particular aluminum and its alloys such as, for example, lithium alloys and in which it is desired to obtain both a cortical zone of practically zero thickness, a grain end without prior addition of refining agents such as AT58 and an absence of pins.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Dental Prosthetics (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Mold Materials And Core Materials (AREA)
  • Casting Devices For Molds (AREA)
  • Soil Working Implements (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
  • Moulds, Cores, Or Mandrels (AREA)

Claims (11)

1. Gießform (15), die die Regulierung der Höhe, auf der sie im Kontakt mit der freien Oberfläche des Metalls bei einem Vertikalguß ist, gestattet, dadurch gekennzeichnet, daß sie wenigstens in ihrem unteren Teil aus einem Metall besteht, daß sie innen mit einer Schicht (16) aus elektrisch isolierendem Material überzogen ist, daß sie längs wenigstens einer Mantellinie auf ihrer ganzen Höhe und ihrer ganzen Wanddicke einen Einsatz (17) aus elektrisch isolierendem Material aufweist, und daß sie äußerlich auf Höhe des unteren Teils mit zwei Anschlußklemmen (18) versehen ist, die zu beiden Seiten des Einsatzes angeordnet und mit einer Wechselstromquelle verbunden sind.
2. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß das Metall, das sie bildet, einen niedrigen elektrischen Widerstand hat.
3. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß sie einen oberen Teil (19) aufweist, der aus einem isolierenden oder mittelmäßig elektrisch leitenden Material besteht.
4. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß das Metall, das sie bildet, zu der von Kupfer, Aluminium und deren Legierungen gebildeten Gruppe gehört.
5. Gießform nach dem Anspruch 4, dadurch gekennzeichnet, daß, wenn das Metall Aluminium und seine Legierungen ist, der innere Überzug eine durch anodische Oxidation erhaltene Aluminiumoxidschicht ist.
6. Gießform nach dem Anspruch 5, dadurch gekennzeichnet, daß die Schicht gefärbt ist.
7. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß der innere Überzug eine Emailschicht ist.
8. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß der innere Überzug eine Fluorkohlenstoffharzschicht ist.
9. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß der innere Überzug mit einem Schmiermittel bedeckt ist.
10. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß die Schicht vom gegossenen Metall durch eine Graphitschicht getrennt ist.
11. Gießform nach dem Anspruch 1, dadurch gekennzeichnet, daß der Einsatz aus einem Material gleicher Zusammensetzung wie der der Schicht ist.
EP87420070A 1986-03-13 1987-03-11 Giessform, die die Regulierung der Höhe der freien Oberfläche von Metallschmelzen zur Berührung mit der Giessform beim vertikalen Giessen gestattet Expired EP0241387B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87420070T ATE39332T1 (de) 1986-03-13 1987-03-11 Giessform, die die regulierung der hoehe der freien oberflaeche von metallschmelzen zur beruehrung mit der giessform beim vertikalen giessen gestattet.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8604117A FR2595596B1 (fr) 1986-03-13 1986-03-13 Lingotiere permettant de regler le niveau suivant lequel elle est en contact avec la surface libre du metal dans une coulee verticale
FR8604117 1986-03-13

Publications (2)

Publication Number Publication Date
EP0241387A1 EP0241387A1 (de) 1987-10-14
EP0241387B1 true EP0241387B1 (de) 1988-12-21

Family

ID=9333414

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87420070A Expired EP0241387B1 (de) 1986-03-13 1987-03-11 Giessform, die die Regulierung der Höhe der freien Oberfläche von Metallschmelzen zur Berührung mit der Giessform beim vertikalen Giessen gestattet

Country Status (12)

Country Link
US (1) US4735255A (de)
EP (1) EP0241387B1 (de)
JP (1) JPS62227553A (de)
KR (1) KR870008644A (de)
CN (1) CN87101863A (de)
AT (1) ATE39332T1 (de)
AU (1) AU579567B2 (de)
DE (1) DE3760022D1 (de)
ES (1) ES2005055B3 (de)
FR (1) FR2595596B1 (de)
GR (1) GR3000001T3 (de)
NZ (1) NZ219581A (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2595597B1 (fr) * 1986-03-13 1988-04-29 Cegedur Dispositif de reglage du niveau de la ligne de contact de la surface libre du metal avec la lingotiere dans une coulee verticale
FR2609656B1 (fr) * 1987-01-15 1989-03-24 Cegedur Procede de reglage au niveau de la ligne de contact de la surface libre du metal avec la lingotiere dans une coulee verticale de produits de section quelconque
JPH04504228A (ja) * 1989-03-20 1992-07-30 オリン コーポレイション 鋳造時における溶融金属の鋳型―内部撹拌
DE4402500C2 (de) * 1994-01-28 1995-12-21 Aeg Elotherm Gmbh Gießkokille
CN105671437A (zh) * 2016-01-25 2016-06-15 陈焕道 一种发动机节气门的制备方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB752271A (en) * 1954-05-17 1956-07-11 Rossi Irving Improvements in moulds for use in the continuous casting of metals and particularly steel
US3467166A (en) * 1967-03-01 1969-09-16 Getselev Zinovy N Method of continuous and semicontinuous casting of metals and a plant for same
SE346234B (de) * 1970-03-03 1972-07-03 Asea Ab
AT303280B (de) * 1970-09-22 1972-11-27 Plansee Metallwerk Kokille für das Stranggießen von Metallen
US3702155A (en) * 1970-12-09 1972-11-07 Kuibyshevsky Metallurigchesky Apparatus for shaping ingots during continuous and semi-continuous casting of metals
JPS59133912A (ja) * 1983-01-17 1984-08-01 ウクラインスキイ・ナウチノ−イスレドヴアテルスキイ・インスチテユ−ト・メタルロフ 縦方向に変化する横断面形状を有する物品を作るための圧延成形機械
JPS59153550A (ja) * 1983-02-23 1984-09-01 Kawasaki Steel Corp 連続鋳造用モ−ルド

Also Published As

Publication number Publication date
FR2595596A1 (fr) 1987-09-18
US4735255A (en) 1988-04-05
EP0241387A1 (de) 1987-10-14
NZ219581A (en) 1988-04-29
DE3760022D1 (en) 1989-01-26
KR870008644A (ko) 1987-10-19
GR3000001T3 (en) 1989-09-29
ATE39332T1 (de) 1989-01-15
CN87101863A (zh) 1987-09-23
ES2005055B3 (es) 1990-11-16
AU6995487A (en) 1987-09-17
JPH0137224B2 (de) 1989-08-04
AU579567B2 (en) 1988-11-24
FR2595596B1 (fr) 1988-04-29
JPS62227553A (ja) 1987-10-06

Similar Documents

Publication Publication Date Title
EP0439981B1 (de) Verfahren und Vorrichtung zur Herstellung von thixotropen metallischen Produkten mittels Strangguss und elektromagnetischem Rühren
EP0275228B1 (de) Verfahren und Anlage zum Schmelzen und Stranggiessen von Metallen
EP0351327B1 (de) Verfahren zur Herstellung von thixotropen metallischen Produkten mittels Strangguss
WO2001007685A2 (fr) Procede de nickelage en continu d'un conducteur en aluminium et dispositif correspondant
EP0241387B1 (de) Giessform, die die Regulierung der Höhe der freien Oberfläche von Metallschmelzen zur Berührung mit der Giessform beim vertikalen Giessen gestattet
FR2688516A1 (fr) Dispositif pour la fabrication de metaux et d'alliages de metaux de grande purete.
CA2017132C (fr) Creuset froid a vidange par le fond
CA1256669A (fr) Procede de reglage du niveau de la ligne de contact de la surface libre du metal avec la lingotiere dans une coulee verticale
EP3898051B1 (de) Delta-phase-messingelektrodendraht für funkenerosionsbearbeitung und verfahren zu seiner herstellung
EP0249565B1 (de) Vorrichtung zur Steuerung des Pegels der Kontaktlinie der freien Metalloberfläche mit der Stranggiesskokille in einen vertikalen Strangguss
CA2018288A1 (fr) Dispositif de traitement par anodisation de pistons en alliage d'aluminium utilises dans les moteurs a combustion interne
FR2711034A1 (fr) Appareil de lévitation et de fusion et son procédé de fonctionnement.
FR2647814A1 (fr) Enceinte utilisable pour recouvrir d'un revetement a base de metal ou d'alliage metallique des objets de forme allongee defilant a travers elle
FR2554829A1 (fr) Procede d'affinage d'un metal par refusion sous laitier electro-conducteur
FR2702402A1 (fr) Procédé et dispositif pour réaliser l'étanchéité latérale lors de la coulée de feuillards ayant des dimensions proches des dimensions finales.
EP0083611B1 (de) Verfahren zum vertikalen stranggiessen von aluminium und dessen legierungen mit hoher geschwindigkeit
EP0038275B1 (de) Vorrichtung zum Stranggiessen von Rohrluppen
FR2517666A1 (fr) Procede de chauffage d'une masselotte de materiau refractaire en fusion
EP0277889B1 (de) Verfahren zur Steuerung des Pegels der Kontaktlinie der freien Metalloberfläche mit der Stranggiesskokille in einen vertikalen Strangguss
WO1996038599A1 (fr) Procede et dispositif pour revetir une bande metallique d'un metal ou d'un alliage a plus bas point de fusion ou de liquide que celui du materiau constituant la bande
EP0467807A1 (de) Verfahren und Vorrichtung zur Dickenkontrolle dünner Stranggussbänder auselektrisch leitendem Material
EP0354857A1 (de) Verfahren zur Herstellung von Überzugskapseln aus Blei und auf diese Weise erhaltene Überzugskapseln
FR2477462A1 (fr) Procede pour mouler par injection des pieces en matiere plastique presentant des formes creuses ou gauches en contre-depouille, et outillage utilise
FR2665653A1 (fr) Procede pour controler l'epaisseur d'une bande metallique couleee en continu sur un cylindre.
WO1986007552A1 (fr) Procede de fabrication d'une electrode filiforme pour l'usinage par electro-erosion

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

Kind code of ref document: A1

Designated state(s): AT BE CH DE ES GB GR IT LI LU NL SE

17P Request for examination filed

Effective date: 19871027

17Q First examination report despatched

Effective date: 19880607

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE ES GB GR IT LI LU NL SE

REF Corresponds to:

Ref document number: 39332

Country of ref document: AT

Date of ref document: 19890115

Kind code of ref document: T

ITF It: translation for a ep patent filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
REF Corresponds to:

Ref document number: 3760022

Country of ref document: DE

Date of ref document: 19890126

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

Ref country code: AT

Payment date: 19890207

Year of fee payment: 3

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

Ref country code: DE

Payment date: 19890208

Year of fee payment: 3

Ref country code: CH

Payment date: 19890208

Year of fee payment: 3

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

Ref country code: SE

Payment date: 19890209

Year of fee payment: 3

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

Ref country code: LU

Payment date: 19890224

Year of fee payment: 3

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

Ref country code: ES

Payment date: 19890313

Year of fee payment: 3

ITTA It: last paid annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19890331

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

Ref country code: NL

Payment date: 19890331

Year of fee payment: 3

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

Ref country code: BE

Payment date: 19890405

Year of fee payment: 3

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

Ref country code: GR

Payment date: 19890411

Year of fee payment: 3

REG Reference to a national code

Ref country code: GR

Ref legal event code: FG4A

Free format text: 3000001

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

Ref country code: AT

Effective date: 19900311

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

Ref country code: SE

Effective date: 19900312

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19900312

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

Ref country code: LI

Effective date: 19900331

Ref country code: CH

Effective date: 19900331

Ref country code: BE

Effective date: 19900331

BERE Be: lapsed

Owner name: CEGEDUR SOC. DE TRANSFORMATION DE L'ALUMINIUM PEC

Effective date: 19900331

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

Ref country code: GR

Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY

Effective date: 19900930

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

Ref country code: NL

Effective date: 19901001

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
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: 19901201

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

Ref country code: GB

Effective date: 19910311

GBPC Gb: european patent ceased through non-payment of renewal fee
REG Reference to a national code

Ref country code: GR

Ref legal event code: MM2A

Free format text: 3000001

EUG Se: european patent has lapsed

Ref document number: 87420070.2

Effective date: 19910110

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 19990301

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

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050311