EP0628970A1 - Decanter centrifuge for the treatment of nuclear products - Google Patents

Decanter centrifuge for the treatment of nuclear products Download PDF

Info

Publication number
EP0628970A1
EP0628970A1 EP94420159A EP94420159A EP0628970A1 EP 0628970 A1 EP0628970 A1 EP 0628970A1 EP 94420159 A EP94420159 A EP 94420159A EP 94420159 A EP94420159 A EP 94420159A EP 0628970 A1 EP0628970 A1 EP 0628970A1
Authority
EP
European Patent Office
Prior art keywords
decanter
bowl
screw
mechanical assembly
bore
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.)
Granted
Application number
EP94420159A
Other languages
German (de)
French (fr)
Other versions
EP0628970B1 (en
Inventor
Michel Robatel
Alain Fraux
Jean-Pierre Davier
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.)
Robatel SLPI SA
Original Assignee
Robatel SLPI 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 Robatel SLPI SA filed Critical Robatel SLPI SA
Publication of EP0628970A1 publication Critical patent/EP0628970A1/en
Application granted granted Critical
Publication of EP0628970B1 publication Critical patent/EP0628970B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B9/00—Drives specially designed for centrifuges; Arrangement or disposition of transmission gearing; Suspending or balancing rotary bowls
    • B04B9/12—Suspending rotary bowls ; Bearings; Packings for bearings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B1/00—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles
    • B04B1/20—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles discharging solid particles from the bowl by a conveying screw coaxial with the bowl axis and rotating relatively to the bowl
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/04—Treating liquids
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/04—Treating liquids
    • G21F9/06—Processing

Definitions

  • the present invention relates to a centrifugal decanter with continuous evacuation of the solid for the treatment of nuclear products.
  • Machines of this type which generally include a mechanical zone which is separated from the active zone by means of a support structure in which a removable biological protection slab is provided.
  • the machine is generally a pendulum decanter with cycles which comprises a tank integral with the carrying structure and inside which is driven in rotation a decanter bowl.
  • the machine comprises a loading tank and a tubing which projects a jet of liquid under pressure for the extraction of the decanted solid.
  • the tank is provided with an evacuation of the clarified liquid, a retractable supply of the suspension to be decanted and a draining of the wet solid after decantation.
  • Cycle operation of the machine requires periodic stops in the flow rate, which involves storing the substance to be decanted.
  • the decanted solid is removed by means of a jet of pressurized liquid which transforms it into a mud which risks blocking the evacuation duct.
  • the decanted solid comprises, due to its evacuation in wet form, a quantity of liquid which decreases the quality of decantation of the substance.
  • the machine bowl is provided with a large diameter in order to be able to place the various elements such as the loading tank and the tubing.
  • the large size of the bowl requires a low speed of rotation due to mechanical stress, which implies poor decantation of the substance.
  • the larger the diameter of the bowl the greater the volume of substances to be treated, which is contrary to the treatment of nuclear products.
  • the purpose of the continuous decanter according to the present invention is to reduce the criticality threshold for the same mass of treated product modifying its geometric shape while improving its quality.
  • the continuous decanter comprises in the mechanical zone an assembly which allows the rotational drive of a decanter bowl and an Archimedes screw placed in the active zone, while sealed means make it possible to decouple the mechanical assembly of the bowl and the screw to be able to intervene on them.
  • the continuous decanter has no bearing or bearing for axially guiding the decanter bowl and the Archimedes screw in the active area.
  • Fig. 1 is a longitudinal section illustrating the continuous decanter according to the present invention.
  • Fig. 2 is an enlarged section showing the device for coupling the bowl and the Archimedes' screw with the mechanical assembly.
  • Fig. 3 and 4 are views illustrating the various steps to be carried out to completely or partially remove the mechanical assembly.
  • Fig. 5 and 6 are sections representing the different stages, after total removal of the mechanical assembly, of the extraction of the bowl and of the Archimedes screw from the active area in a sealed container or "castle".
  • the decanter 1 comprises a mechanical zone M which is separated from an active zone A by means of a support structure 2 in which a removable slab 2 a of biological protection is provided.
  • the slab 2 a is pierced with a first bore 2 b which communicates co-axially with a second bore 2 c of smaller diameter passing through the rest of the said slab to form a passage between the two zones A and B.
  • the first bore 2 b is separated from the second 2 c by two successive shoulders 2 d , 2 e , the reason of which will be seen more clearly below.
  • a metal frame 1 a which rests on the supporting structure 2.
  • the frame 1 a supports in the known manner a motor 1 b which drives in rotation by means of one or more belts a reduction gear 1 tsp .
  • a tube 1 d in which is provided a bearing 1 e .
  • a bearing 1 e Inside the bearing 1 e are arranged ball or roller bearings for the axial guidance of a hollow sleeve 1 f , one of the ends of which cooperates by means of an intermediate piece 1 i with the reducer 1 c for its rotational drive.
  • the sleeve 1 f has a flange 1 g which is placed co-axially inside the bore 2 b of the biological slab 2 a . Inside the bore 2b, the flange 1g is fixed by screws on an intermediate disc 3 which is secured to an axle 4 has through the bore 2 c.
  • the axis 4a is secured to a bowl decanter 4 provided in the active region A for driving it in rotation. Inside the bowl 4 is arranged in the known manner an Archimedes screw 5 secured to a shaft 5 a which crosses the axis 4 a of the bowl and which is guided axially inside the sleeve 1 f to come cooperate with the reducer 1 c .
  • the underside of the intermediate disc 3 is provided just above the shoulder 2 d of the bore 2 b determining therewith an operating clearance X.
  • the shoulder 2 d has an O-ring 2 f whose outside diameter is slightly smaller than that of the intermediate disc 3.
  • a tank 6 which is fixed to the underside of the support structure 2 so that it surrounds the removable slab 2 a .
  • the tank 6 has in its upper part a discharge 6 a of the clarified liquid.
  • a fixed supply 6 b for the introduction of the substance to be decanted.
  • the tank 6 has below the feed 6 b a chute-shaped opening 6 c for the extraction of the decanted solid.
  • a 1- hour double-sided joint is placed on the one hand around the periphery of the bore 2b and on the other hand on the outside face of the bearing 1e to constitute a sealed separation between the active zone A and the mechanical zone M during the operation of the decanter 1.
  • bowl 4 and the screw 5 are not axially supported in their lower parts and conical by bearings or bearings to facilitate on the one hand their removal and on the other hand the intervention on the mechanical assembly when a breakdown occurs, as will be seen better below.
  • the continuous decanter 1 described above operates on the same principle as all the other continuous decanters.
  • the motor 1b via the reducer 1c , drives the settling bowl 4 and the Archimedes screw 5 at different speeds.
  • the radioactive substance to be treated is fed into the settling bowl 4 is carried out by the fixed tube 6 b so that said substance arrives in the middle of the thread of the screw 5.
  • the speed difference between the bowl 4 and the screw 5 makes it possible to direct the solid decanted into the lower or conical part of the decanter for its extraction through the orifice 6 c of the tank 6.
  • the clarified liquid performs the opposite path to be evacuated by overflow by means of the tubing 6 a .
  • An essential feature of the continuous decanter 1 described above is that when a failure occurs in the mechanical assembly located in zone M, an operator can intervene without risk of being contaminated.
  • the removal of the entire mechanical assembly that is to say for example from the frame 1 a , from the motor 1 b to the reducer 1 c or even the bearing 1 e and the sleeve 1 f , can be carried out without risk of transfer of radioactive particles between the two zones.
  • the operator can then freely disassemble the entire mechanical assembly such as the bearing 1c and the sleeve 1f in order to replace the various bearings if necessary, as shown in FIG. 4. Similarly, the operator can change the reducer 1 c and the motor 1 b if the case arises.
  • the operator proceeds in the reverse path to reassemble the mechanical assembly of the continuous decanter 1, the seal between the zone M and the zone A remaining perfect because the disc 3 is in abutment against the shoulder 2 d .
  • the continuous decanter 1 is shown without its frame 1 a , that is to say when the operator has carried out its total removal, as described above.
  • the removal of the frame 1 a allows the operator to intervene on the settling bowl 4 and the Archimedes screw 5 when these are defective. This intervention is carried out in the known manner in a sealed container or "castle", the latter being shown in phantom.
  • Lifting means are fixed on the removable slab 2 a to lift the assembly made up of the bowl and the screw inside the watertight "castle". It is noted that the withdrawal is possible, given that the intermediate disc 3 is supported on the shoulder 2 d of the bore 2 b and that the screw is against the conical part of the bowl.
  • the tank 6 remains integral with the slab 2 as well as the supply 6 b .
  • the removal of the bowl 4 and the screw 5 is carried out without human intervention in the active area A.
  • a sealed drawer closes the opening of the supporting structure 2 in which is placed the slab 2 a so that no communication can be made between the two zones.
  • the installation of another bowl provided with another screw is carried out under watertight "castle". The operator then proceeds to assemble the mechanical assembly described above until the bowl and the screw are connected to the reducer 1 c .
  • the continuous decanter 1 makes it possible to extract the solid when dry, which considerably improves the quality of decantation of the substance. In addition, continuous operation increases the efficiency of the machine and avoids storing the substance to be decanted.
  • the elongated shape of the screw 5 modifies the geometry of the treated product which allows, for the same mass of product to be treated, more radioactive substances without ever reaching the criticality threshold.

Abstract

The settler (decanter) comprises a mechanical assembly (1a, 1b, 1c, 1d, 1e, 1f and 3) which is placed in the mechanical region (M) in order to allow a settler bowl (4) and an Archimedean screw (5) which are arranged in the active region (A) to be driven in rotation about a vertical axis, in which leaktight means make it possible to decouple the mechanical assembly from the bowl (4) and from the screw (5) in order to make it possible to operate thereon without risk of contamination. <IMAGE>

Description

La présente invention a trait à une décanteuse centrifuge à évacuation en continu du solide pour le traitement des produits nucléaires.The present invention relates to a centrifugal decanter with continuous evacuation of the solid for the treatment of nuclear products.

On connaît des machines de ce genre qui comprennent généralement une zone mécanique qui est séparée de la zone active par l'intermédiaire d'une structure porteuse dans laquelle est prévue une dalle amovible de protection biologique. La machine est généralement une décanteuse pendulaire à cycles qui comprend une cuve solidaire de la structure porteuse et à l'intérieur de laquelle est entraîné en rotation un bol décanteur. A la manière usuelle, la machine comprend un bac de chargement et une tubulure qui projette un jet de liquide sous pression pour l'extraction du solide décanté.Machines of this type are known which generally include a mechanical zone which is separated from the active zone by means of a support structure in which a removable biological protection slab is provided. The machine is generally a pendulum decanter with cycles which comprises a tank integral with the carrying structure and inside which is driven in rotation a decanter bowl. In the usual way, the machine comprises a loading tank and a tubing which projects a jet of liquid under pressure for the extraction of the decanted solid.

La cuve est pourvue d'une évacuation du liquide clarifié, d'une alimentation rétractable de la suspension à décanter et d'une vidange du solide humide après décantation.The tank is provided with an evacuation of the clarified liquid, a retractable supply of the suspension to be decanted and a draining of the wet solid after decantation.

Le fonctionnement par cycles de la machine nécessite des arrêts périodiques du débit, ce qui implique un stockage de la substance à décanter. Le solide décanté est éliminé au moyen d'un jet de liquide sous pression qui le transforme en une boue risquant de boucher le conduit d'évacuation. De plus, le solide décanté comporte du fait de son évacuation sous forme humide une quantité de liquide qui diminue la qualité de décantation de la substance.Cycle operation of the machine requires periodic stops in the flow rate, which involves storing the substance to be decanted. The decanted solid is removed by means of a jet of pressurized liquid which transforms it into a mud which risks blocking the evacuation duct. In addition, the decanted solid comprises, due to its evacuation in wet form, a quantity of liquid which decreases the quality of decantation of the substance.

Le bol de la machine est prévu de grand diamètre pour pouvoir placer les différents éléments tels que le bac de chargement et la tubulure. La grande dimension du bol oblige une vitesse de rotation faible due aux contraintes mécaniques, ce qui implique une mauvaise décantation de la substance. Enfin, plus le diamètre du bol est grand, plus le volume de substances à traiter est conséquent, ce qui est contraire au traitement des produits nucléaires.The machine bowl is provided with a large diameter in order to be able to place the various elements such as the loading tank and the tubing. The large size of the bowl requires a low speed of rotation due to mechanical stress, which implies poor decantation of the substance. Finally, the larger the diameter of the bowl, the greater the volume of substances to be treated, which is contrary to the treatment of nuclear products.

C'est à ces inconvénients qu'entend plus particulièrement remédier la présente invention.It is these drawbacks that the present invention intends to remedy more particularly.

La décanteuse continue suivant la présente invention a pour but de réduire le seuil de criticité pour une même masse de produit traité modifiant sa forme géométrique tout en améliorant sa qualité.The purpose of the continuous decanter according to the present invention is to reduce the criticality threshold for the same mass of treated product modifying its geometric shape while improving its quality.

A cet effet, la décanteuse continue comprend dans la zone mécanique un ensemble qui permet l'entraînement en rotation d'un bol décanteur et d'une vis d'Archimède placés dans la zone active, tandis que des moyens étanches permettent de désaccoupler l'ensemble mécanique du bol et de la vis pour pouvoir intervenir sur ceux-ci.To this end, the continuous decanter comprises in the mechanical zone an assembly which allows the rotational drive of a decanter bowl and an Archimedes screw placed in the active zone, while sealed means make it possible to decouple the mechanical assembly of the bowl and the screw to be able to intervene on them.

En outre, la décanteuse continue ne comporte aucun palier ou roulement pour guider axialement le bol décanteur et la vis d'Archimède dans la zone active.In addition, the continuous decanter has no bearing or bearing for axially guiding the decanter bowl and the Archimedes screw in the active area.

Le dessin annexé, donné à titre d'exemple, permettra de mieux comprendre l'invention, les caractéristiques qu'elle présente et les avantages qu'elle est susceptible de procurer :The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing:

Fig. 1 est une coupe longitudinale illustrant la décanteuse continue suivant la présente invention.Fig. 1 is a longitudinal section illustrating the continuous decanter according to the present invention.

Fig. 2 est une coupe agrandie montrant le dispositif d'accouplement du bol et de la vis d'Archimède avec l'ensemble mécanique.Fig. 2 is an enlarged section showing the device for coupling the bowl and the Archimedes' screw with the mechanical assembly.

Fig. 3 et 4 sont des vues illustrant les différentes étapes à effectuer pour retirer totalement ou partiellement l'ensemble mécanique.Fig. 3 and 4 are views illustrating the various steps to be carried out to completely or partially remove the mechanical assembly.

Fig. 5 et 6 sont des coupes représentant les différentes étapes, après retrait total de l'ensemble mécanique, de l'extraction du bol et de la vis d'Archimède de la zone active dans un conteneur ou "château" étanche.Fig. 5 and 6 are sections representing the different stages, after total removal of the mechanical assembly, of the extraction of the bowl and of the Archimedes screw from the active area in a sealed container or "castle".

On a représenté en fig. 1 et 2 une décanteuse centrifuge 1 à évacuation continue du solide traité. La décanteuse 1 comprend une zone mécanique M qui est séparée d'une zone active A par l'intermédiaire d'une structure porteuse 2 dans laquelle est prévue une dalle amovible 2a de protection biologique. La dalle 2a est percée d'un premier alésage 2b qui communique co-axialement avec un second alésage 2c de plus faible diamètre traversant le reste de ladite dalle pour former un passage entre les deux zones A et B.There is shown in fig. 1 and 2 a centrifugal decanter 1 with continuous evacuation of the treated solid. The decanter 1 comprises a mechanical zone M which is separated from an active zone A by means of a support structure 2 in which a removable slab 2 a of biological protection is provided. The slab 2 a is pierced with a first bore 2 b which communicates co-axially with a second bore 2 c of smaller diameter passing through the rest of the said slab to form a passage between the two zones A and B.

Le premier alésage 2b est séparé du second 2c par deux épaulements successifs 2d, 2e dont on verra mieux plus loin la raison.The first bore 2 b is separated from the second 2 c by two successive shoulders 2 d , 2 e , the reason of which will be seen more clearly below.

Dans la zone M est placé un bâti métallique 1a qui prend appui sur la structure porteuse 2. Le bâti 1a supporte à la manière connue un moteur 1b qui entraîne en rotation par l'intermédiaire d'une ou de plusieurs courroies un réducteur 1c.In the zone M is placed a metal frame 1 a which rests on the supporting structure 2. The frame 1 a supports in the known manner a motor 1 b which drives in rotation by means of one or more belts a reduction gear 1 tsp .

Sur le bâti 1a et en dessous du réducteur 1c est soudé suivant un axe vertical un tube 1d dans lequel est prévu un palier 1e. A l'intérieur du palier 1e sont disposés des roulements à billes ou à galets pour le guidage axial d'un manchon creux 1f dont l'une des extrémités coopère au moyen d'une pièce intermédiaire 1i avec le réducteur 1c pour son entraînement en rotation. Le manchon 1f présente une bride 1g qui est placée co-axialement à l'intérieur de l'alésage 2b de la dalle biologique 2a. A l'intérieur de l'alésage 2b, la bride 1g est fixée au moyen de vis sur un disque intermédiaire 3 qui est solidaire d'un axe 4a traversant l'alésage 2c. L'axe 4a est solidaire d'un bol décanteur 4 prévu dans la zone active A pour son entraînement en rotation. A l'intérieur du bol 4 est disposée à la manière connue une vis d'Archimède 5 solidaire d'un arbre 5a qui traverse l'axe 4a du bol et qui est guidé axialement à l'intérieur du manchon 1f pour venir coopérer avec le réducteur 1c.On the frame 1 a and below the reducer 1 c is welded along a vertical axis a tube 1 d in which is provided a bearing 1 e . Inside the bearing 1 e are arranged ball or roller bearings for the axial guidance of a hollow sleeve 1 f , one of the ends of which cooperates by means of an intermediate piece 1 i with the reducer 1 c for its rotational drive. The sleeve 1 f has a flange 1 g which is placed co-axially inside the bore 2 b of the biological slab 2 a . Inside the bore 2b, the flange 1g is fixed by screws on an intermediate disc 3 which is secured to an axle 4 has through the bore 2 c. The axis 4a is secured to a bowl decanter 4 provided in the active region A for driving it in rotation. Inside the bowl 4 is arranged in the known manner an Archimedes screw 5 secured to a shaft 5 a which crosses the axis 4 a of the bowl and which is guided axially inside the sleeve 1 f to come cooperate with the reducer 1 c .

La face inférieure du disque intermédiaire 3 est prévue juste au-dessus de l'épaulement 2d de l'alésage 2b déterminant avec celui-ci un jeu de fonctionnement X. De plus, l'épaulement 2d comporte un joint torique 2f dont le diamètre extérieur est légèrement inférieur à celui du disque intermédiaire 3.The underside of the intermediate disc 3 is provided just above the shoulder 2 d of the bore 2 b determining therewith an operating clearance X. In addition, the shoulder 2 d has an O-ring 2 f whose outside diameter is slightly smaller than that of the intermediate disc 3.

Dans la zone active A et autour du bol 4 est prévue une cuve 6 qui est fixée sur la face inférieure de la structure porteuse 2 de manière qu'elle entoure la dalle amovible 2a. La cuve 6 comporte dans sa partie supérieure une évacuation 6a du liquide clarifié. En outre, dans la partie inférieure de la cuve 6 est prévue une alimentation fixe 6b pour l'introduction de la substance à décanter. La cuve 6 présente en dessous de l'alimentation 6b une ouverture en forme de goulotte 6c pour l'extraction du solide décanté.In the active area A and around the bowl 4 is provided a tank 6 which is fixed to the underside of the support structure 2 so that it surrounds the removable slab 2 a . The tank 6 has in its upper part a discharge 6 a of the clarified liquid. In addition, in the lower part of the tank 6 is provided a fixed supply 6 b for the introduction of the substance to be decanted. The tank 6 has below the feed 6 b a chute-shaped opening 6 c for the extraction of the decanted solid.

Un joint à double appui 1h est placé d'une part sur le pourtour de l'alésage 2b et d'autre part sur la face extérieur du palier 1e pour constituer une séparation étanche entre la zone active A et la zone mécanique M lors du fonctionnement de la décanteuse 1.A 1- hour double-sided joint is placed on the one hand around the periphery of the bore 2b and on the other hand on the outside face of the bearing 1e to constitute a sealed separation between the active zone A and the mechanical zone M during the operation of the decanter 1.

On remarque que le bol 4 et la vis 5 ne sont pas soutenus axialement dans leurs parties inférieures et coniques par des paliers ou des roulements pour faciliter d'une part leur retrait et d'autre part l'intervention sur l'ensemble mécanique lorqu'une panne survient, comme on le verra mieux plus loin.Note that the bowl 4 and the screw 5 are not axially supported in their lower parts and conical by bearings or bearings to facilitate on the one hand their removal and on the other hand the intervention on the mechanical assembly when a breakdown occurs, as will be seen better below.

La décanteuse continue 1 décrite précédemment fonctionne suivant le même principe que toutes les autres décanteuses continues.The continuous decanter 1 described above operates on the same principle as all the other continuous decanters.

Le moteur 1b, par l'intermédiaire du réducteur 1c, entraîne le bol décanteur 4 et de la vis d'Archimède 5 à des vitesses différentes.The motor 1b , via the reducer 1c , drives the settling bowl 4 and the Archimedes screw 5 at different speeds.

L'alimentation de la substance radio-active à traiter dans le bol décanteur 4 s'effectue par la tubulure fixe 6b de manière que ladite substance arrive au milieu du filet de la vis 5. La différence de vitesses entre le bol 4 et la vis 5 permet de diriger le solide décanté dans la partie inférieure ou conique de la décanteuse pour son extraction par l'orifice 6c de la cuve 6. Par contre, le liquide clarifié effectue le chemin inverse pour être évacué par débordement au moyen de la tubulure 6a.The radioactive substance to be treated is fed into the settling bowl 4 is carried out by the fixed tube 6 b so that said substance arrives in the middle of the thread of the screw 5. The speed difference between the bowl 4 and the screw 5 makes it possible to direct the solid decanted into the lower or conical part of the decanter for its extraction through the orifice 6 c of the tank 6. On the other hand, the clarified liquid performs the opposite path to be evacuated by overflow by means of the tubing 6 a .

Une particularité essentielle de la décanteuse continue 1 ci-dessus décrite réside dans le fait que lorsqu'une panne survient dans l'ensemble mécanique se trouvant dans la zone M, un opérateur peut intervenir sans risque d'être contaminé.An essential feature of the continuous decanter 1 described above is that when a failure occurs in the mechanical assembly located in zone M, an operator can intervene without risk of being contaminated.

En effet, le retrait de tout l'ensemble mécanique, c'est-à-dire par exemple du bâti 1a, du moteur 1b jusqu'au réducteur 1c voire le palier 1e et le manchon 1f, peut être réalisé sans risque de transfert de particules radio-actives entre les deux zones.Indeed, the removal of the entire mechanical assembly, that is to say for example from the frame 1 a , from the motor 1 b to the reducer 1 c or even the bearing 1 e and the sleeve 1 f , can be carried out without risk of transfer of radioactive particles between the two zones.

En fig. 3, on a représenté la première étape que l'opérateur doit effectuer avant toute intervention afin de rendre totalement étanches l'une de l'autre les zones A et M. Pour cela, l'opérateur relève le joint statique 1h de manière à le faire coulisser sur la paroi extérieure du palier 1e. Ensuite, il retire les vis qui retiennent la bride 1g du manchon 1f sur le disque intermédiaire 3 solidaire de l'axe 4a du bol 4. Lorsque le désaccouplement est réalisé, l'on constate que la face inférieure du disque 3 vient en appui sur l'épaulement 2d de l'alésage 2b pour écraser le joint 2f pour constituer une étanchéité parfaite entre les deux zones. On constate que le jeu X prévu entre la face inférieure du disque 3 et l'épaulement 2d est nul, étant donné que le bol 4 est descendu verticalement à l'intérieur de la cuve 6 sans risquer de prendre appui sur la périphérie de la tubulure supérieure 6a. Enfin, l'opérateur démonte le réducteur 1c pour que l'axe 5a de la vis 5 soit libéré. On constate que lorsque l'axe 5a est libre axialement, la vis 5 descend verticalement pour venir prendre appui par l'intermédiaire de son filet sur la partie conique du bol 4.In fig. 3, the first step has been shown that the operator must perform before any intervention in order to make zones A and M completely sealed from each other. For this, the operator raises the static seal for 1 hour so as to slide it on the outside wall level 1 e . Then, he removes the screws which retain the flange 1 g of the sleeve 1 f on the intermediate disc 3 secured to the axis 4 a of the bowl 4. When the uncoupling is carried out, it is noted that the underside of the disc 3 comes resting on the shoulder 2 d of the bore 2 b to crush the seal 2 f to constitute a perfect seal between the two zones. It can be seen that the clearance X provided between the underside of the disc 3 and the shoulder 2 d is zero, given that the bowl 4 is lowered vertically inside the tank 6 without risking bearing on the periphery of the upper tube 6 a . Finally, the operator dismantles the reducer 1 c so that the axis 5 a of the screw 5 is released. It can be seen that when the axis 5 a is axially free, the screw 5 descends vertically to come to bear via its thread on the conical part of the bowl 4.

Lorsque ces différentes étapes sont réalisées, l'opérateur peut ensuite librement démonter tout l'ensemble mécanique tel que le palier le et le manchon 1f en vue de remplacer les différents roulements si cela est nécessaire, comme représenté en fig. 4. De même, l'opérateur peut changer le réducteur 1c et le moteur 1b si le cas se présente.When these various steps are carried out, the operator can then freely disassemble the entire mechanical assembly such as the bearing 1c and the sleeve 1f in order to replace the various bearings if necessary, as shown in FIG. 4. Similarly, the operator can change the reducer 1 c and the motor 1 b if the case arises.

L'opérateur procède en chemin inverse pour remonter l'ensemble mécanique de la décanteuse continue 1, l'étanchéité entre la zone M et la zone A demeurant parfaite du fait que le disque 3 est en appui contre l'épaulement 2d.The operator proceeds in the reverse path to reassemble the mechanical assembly of the continuous decanter 1, the seal between the zone M and the zone A remaining perfect because the disc 3 is in abutment against the shoulder 2 d .

En fig. 5 et 6, on a représenté la décanteuse continue 1 sans son bâti 1a, c'est-à-dire lorsque l'opérateur a procédé à son retrait total, comme décrit précédemment. Le retrait du bâti 1a permet à l'opérateur d'intervenir sur le bol décanteur 4 et la vis d'Archimède 5 lorsque ceux-ci sont défectueux. Cette intervention s'effectue à la manière connue sous conteneur ou "château" étanche, ce dernier étant représenté en traits mixtes.In fig. 5 and 6, the continuous decanter 1 is shown without its frame 1 a , that is to say when the operator has carried out its total removal, as described above. The removal of the frame 1 a allows the operator to intervene on the settling bowl 4 and the Archimedes screw 5 when these are defective. This intervention is carried out in the known manner in a sealed container or "castle", the latter being shown in phantom.

Des moyens de levage non représentés sont fixés sur la dalle amovible 2a pour soulever l'ensemble composé du bol et de la vis à l'intérieur du "château" étanche. On remarque que le retrait est possible, étant donné que le disque intermédiaire 3 est en appui sur l'épaulement 2d de l'alésage 2b et que la vis est contre la partie conique du bol.Lifting means, not shown, are fixed on the removable slab 2 a to lift the assembly made up of the bowl and the screw inside the watertight "castle". It is noted that the withdrawal is possible, given that the intermediate disc 3 is supported on the shoulder 2 d of the bore 2 b and that the screw is against the conical part of the bowl.

On note que la cuve 6 reste solidaire de la dalle 2 ainsi que l'alimentation 6b. On remarque que le retrait du bol 4 et de la vis 5 est réalisé sans intervention humaine dans la zone active A. Avant de retirer le "château" représenté en traits mixtes, un tiroir étanche vient fermer l'ouverture de la structure porteuse 2 dans laquelle est placée la dalle 2a pour qu'aucune communication ne puisse se faire entre les deux zones. La mise en place d'un autre bol pourvu d'une autre vis est réalisée sous "château" étanche. L'opérateur procède ensuite au montage de l'ensemble mécanique décrit précédemment jusqu'à raccorder le bol et la vis au réducteur 1c.It is noted that the tank 6 remains integral with the slab 2 as well as the supply 6 b . Note that the removal of the bowl 4 and the screw 5 is carried out without human intervention in the active area A. Before removing the "castle" shown in phantom, a sealed drawer closes the opening of the supporting structure 2 in which is placed the slab 2 a so that no communication can be made between the two zones. The installation of another bowl provided with another screw is carried out under watertight "castle". The operator then proceeds to assemble the mechanical assembly described above until the bowl and the screw are connected to the reducer 1 c .

La décanteuse continue 1 permet d'extraire le solide à sec, ce qui améliore considérablement la qualité de décantation de la subtance. En outre, le fonctionnement en continu augmente le rendement de la machine et évite de stocker de la substance à décanter.The continuous decanter 1 makes it possible to extract the solid when dry, which considerably improves the quality of decantation of the substance. In addition, continuous operation increases the efficiency of the machine and avoids storing the substance to be decanted.

On constate que la réduction du diamètre de la vis 5 par rapport aux machines classiques pour un débit équivalent permet d'augmenter considérablement la vitesse de rotation de celle-ci. Cette vitesse de rotation élevée des décanteuses centrifuges continues 1 suivant l'invention et l'extraction du solide décanté à sec améliore considérablement la qualité de décantation de la substance.It is found that reducing the diameter of the screw 5 compared to conventional machines for an equivalent flow rate makes it possible to considerably increase the speed of rotation of the latter. This high speed of rotation of the continuous centrifugal decanters 1 according to the invention and the extraction of the dry decanted solid considerably improves the quality of settling of the substance.

En outre, la forme allongée de la vis 5 modifie la géométrie du produit traité ce qui permet, pour une même masse de produit de traiter, des substances plus radio-actives sans jamais atteindre le seuil de criticité.In addition, the elongated shape of the screw 5 modifies the geometry of the treated product which allows, for the same mass of product to be treated, more radioactive substances without ever reaching the criticality threshold.

Claims (8)

Décanteuse continue pour le traitement de produits nucléaires du genre comprenant une zone active (A) séparée d'une zone mécanique (M) par une structure porteuse (2), caractérisée en ce qu'un ensemble mécanique (1a, 1b, 1c, 1d, 1e, 1f, et 3) est placé dans la zone mécanique (M) pour permettre l'entraînement en rotation autour d'un axe vertical d'un bol décanteur (4) et d'une vis d'Archimède (5) disposés dans la zone active (A) et en ce que des moyens étanches permettent de désaccoupler l'ensemble mécanique du bol (4) et de la vis (5) pour pouvoir intervenir sur ceux-ci sans risque de contamination.Continuous decanter for the treatment of nuclear products of the kind comprising an active area (A) separated from a mechanical area (M) by a support structure (2), characterized in that a mechanical assembly (1 a , 1 b , 1 c , 1 d , 1 e , 1 f , and 3) is placed in the mechanical zone (M) to allow the drive in rotation around a vertical axis of a decanter bowl (4) and a screw d 'Archimedes (5) arranged in the active area (A) and in that sealed means allow the mechanical assembly of the bowl (4) and the screw (5) to be uncoupled in order to be able to intervene on them without risk of contamination . Décanteuse continue suivant la revendication 1, caractérisée en ce que les moyens consistent en un alésage (2b) percé dans la dalle amovible (2a) de la structure porteuse (2) dont l'un au moins des épaulements (2d) comporte un joint torique (2f), tandis que l'entraînement en rotation du bol décanteur (4) s'effectue par un arbre (4a) traversant la dalle amovible (2a) par un alésage (2c) pour être relié par l'intermédiaire d'un disque (3) à un manchon (1f) guidé axialement dans un bâti (1a) pour ccopérer avec un réducteur (1c) de manière qu'il existe un jeu (X) entre l'épaulement (2d) et le disque (3) en position de fonctionnement pour permettre de désaccoupler l'ensemble mécanique du bol (4) et de la vis (5) pour pouvoir intervenir sur ceux-ci sans risque de contamination.Continuous decanter according to claim 1, characterized in that the means consist of a bore (2 b ) pierced in the removable slab (2 a ) of the supporting structure (2) of which at least one of the shoulders (2 d ) comprises an O-ring (2 f ), while the decanter bowl (4) is rotated by a shaft (4 a ) passing through the removable slab (2 a ) by a bore (2 c ) to be connected by through a disc (3) with a sleeve (1 f ) guided axially in a frame (1 a ) to work with a reducer (1 c ) so that there is a clearance (X) between the shoulder (2 d ) and the disc (3) in the operating position to allow the mechanical assembly of the bowl (4) and the screw (5) to be uncoupled so as to be able to work on them without risk of contamination. Décanteuse continue suivant la revendication 2, caractérisée en ce qu'un joint (1h) entoure d'une part l'alésage (2b) et d'autre part la paroi extérieure d'un palier (1e) pour constituer une étanchéité entre la zone (M) et la zone (A) en position de fonctionnement.Continuous decanter according to claim 2, characterized in that a seal (1 h ) surrounds on the one hand the bore (2 b ) and on the other hand the outer wall of a bearing (1 e ) to form a seal between zone (M) and zone (A) in the operating position. Décanteuse suivant la revendication 1, caractérisée en ce que l'étanchéité entre les zones (A et M) est effectuée par l'intermédiaire du disque (3) qui vient prendre appui sur l'épaulement (2d) de l'alésage (2b) pour écraser le joint (2f) lorsque l'ensemble mécanique est retiré.Decanter according to claim 1, characterized in that the seal between the zones (A and M) is effected by means of the disc (3) which comes to bear on the shoulder (2 d ) of the bore (2 b ) to crush the seal (2 f ) when the mechanical assembly is removed. Décanteuse suivant la revendication 1, caractérisée en ce que le bol décanteur (4) et la vis d'Archimède (5) sont guidés axialement uniquement dans la zone (M) au moyen de roulements et d'un palier (1e).Decanter according to claim 1, characterized in that the decanter bowl (4) and the Archimedes screw (5) are guided axially only in the area (M) by means of bearings and a bearing (1 e ). Décanteuse suivant la revendication 1, caractérisée en ce que lors du démontage de l'ensemble mécanique, la vis d'Archimède (5) vient prendre appui sur la partie conique du bol décanteur (4).Decanter according to claim 1, characterized in that during the dismantling of the mechanical assembly, the Archimedes screw (5) comes to bear on the conical part of the decanter bowl (4). Décanteuse continue suivant la revendication 1, caractérisée en ce que le jeu (X) est nul lorsque l'ensemble mécanique est retiré.Continuous decanter according to claim 1, characterized in that the play (X) is zero when the mechanical assembly is removed. Décanteuse continue suivant la revendication 1, caractérisée en ce que l'alimentation (6b) est fixée sur la cuve (6) qui est solidaire de la structure porteuse (2).Continuous decanter according to claim 1, characterized in that the feed (6 b ) is fixed to the tank (6) which is integral with the support structure (2).
EP94420159A 1993-06-07 1994-06-02 Decanter centrifuge for the treatment of nuclear products Expired - Lifetime EP0628970B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9307020A FR2706216B1 (en) 1993-06-07 1993-06-07 Continuous decanter for processing nuclear products.
FR9307020 1993-06-07

Publications (2)

Publication Number Publication Date
EP0628970A1 true EP0628970A1 (en) 1994-12-14
EP0628970B1 EP0628970B1 (en) 1997-08-20

Family

ID=9448002

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94420159A Expired - Lifetime EP0628970B1 (en) 1993-06-07 1994-06-02 Decanter centrifuge for the treatment of nuclear products

Country Status (5)

Country Link
US (1) US5494579A (en)
EP (1) EP0628970B1 (en)
JP (1) JPH0712994A (en)
DE (1) DE69405051T2 (en)
FR (1) FR2706216B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0690456A1 (en) * 1994-07-01 1996-01-03 Abb Atom Ab Method and apparatus for the treatment of aerosols
US8529425B2 (en) 2007-12-07 2013-09-10 Tomoe Engineering Co., Ltd. Horizontal centrifugal separator in which the hermeticity of a casing is improved by using a sealing element having a simple structure

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE9802116D0 (en) * 1998-06-15 1998-06-15 Alfa Laval Ab decanter
US6296765B1 (en) 1998-10-21 2001-10-02 Baldwin Filters, Inc. Centrifuge housing for receiving centrifuge cartridge and method for removing soot from engine oil
US6579218B1 (en) 1998-09-25 2003-06-17 Analytical Engineering, Inc. Centrifugal filter utilizing a partial vacuum condition to effect reduced air drag on the centrifuge rotor
US6517475B1 (en) 1998-09-25 2003-02-11 Baldwin Filters, Inc. Centrifugal filter for removing soot from engine oil
US6213929B1 (en) * 1998-09-25 2001-04-10 Analytical Engineering, Inc. Motor driven centrifugal filter
US6520902B1 (en) 1998-10-21 2003-02-18 Baldwin Filters, Inc. Centrifuge cartridge for removing soot from engine oil
US6056685A (en) * 1999-05-17 2000-05-02 G-Force Llc Centrifuge having selectively operable harmonic drive for scroll conveyor
US6428700B1 (en) 2000-09-06 2002-08-06 Baldwin Filters, Inc. Disposable centrifuge cartridge backed up by reusable cartridge casing in a centrifugal filter for removing soot from engine oil
US6589154B2 (en) * 2001-05-30 2003-07-08 Alfa Laval Inc. Decanter centrifuge with a gear box mounted on the bowl
EP1849524B1 (en) * 2006-04-25 2016-09-07 Ferrum AG Sealing assembly for a centrifuge
ES2594622T3 (en) * 2006-04-25 2016-12-21 Ferrum Ag Bearing arrangement for a centrifuge
SE531141C2 (en) * 2007-05-10 2009-01-07 Alfa Laval Corp Ab Centrifugal separator with conveyor thread that prevents separated particles from clogging the inside of the rotor
JP5571919B2 (en) * 2009-07-31 2014-08-13 巴工業株式会社 Vertical centrifuge and method for recovering centrifuge liquid
GB201005140D0 (en) * 2010-03-26 2010-05-12 Spaans Babcock Ltd An archimedean screw apparatus
JP5048165B1 (en) * 2012-06-11 2012-10-17 巴工業株式会社 Rotation processing device seal mechanism
EP2883947B1 (en) * 2013-12-10 2019-08-07 Alfa Laval Corporate AB Continuous purification of motor oils using a three-phase separator
CN109444386A (en) * 2018-12-06 2019-03-08 安徽财经大学 A kind of unginned cotton regain measurement device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2039546A5 (en) * 1969-04-15 1971-01-15 Robatel Slpi Centrifugal decantor for dangerous - suspensions
US4142669A (en) * 1968-01-10 1979-03-06 Robatel S.L.P.I. Continuously operating centrifugal separators
FR2570541A1 (en) * 1984-09-19 1986-03-21 Foster Miller Inc INSTALLATION FOR SEPARATING LIQUIDS FROM SOLIDS, PARTICULARLY RADIOACTIVE
DE3501341A1 (en) * 1984-12-22 1986-07-03 Klöckner-Humboldt-Deutz AG, 5000 Köln Solid-bowl conveyor screw centrifuge
FR2577150A1 (en) * 1985-02-08 1986-08-14 Robatel Slpi IMPROVEMENTS TO CENTRIFUGAL DECANTERS OF THE PENDULAR TYPE
FR2624764A1 (en) * 1987-12-16 1989-06-23 Robatel Slpi CENTRIFUGAL DECANTER WITH RETRACTABLE FEEDER

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2612696A1 (en) * 1975-04-01 1976-10-14 Pennwalt Corp FULL-CASE DECANTING CENTRIFUGE

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4142669A (en) * 1968-01-10 1979-03-06 Robatel S.L.P.I. Continuously operating centrifugal separators
FR2039546A5 (en) * 1969-04-15 1971-01-15 Robatel Slpi Centrifugal decantor for dangerous - suspensions
FR2570541A1 (en) * 1984-09-19 1986-03-21 Foster Miller Inc INSTALLATION FOR SEPARATING LIQUIDS FROM SOLIDS, PARTICULARLY RADIOACTIVE
DE3501341A1 (en) * 1984-12-22 1986-07-03 Klöckner-Humboldt-Deutz AG, 5000 Köln Solid-bowl conveyor screw centrifuge
FR2577150A1 (en) * 1985-02-08 1986-08-14 Robatel Slpi IMPROVEMENTS TO CENTRIFUGAL DECANTERS OF THE PENDULAR TYPE
FR2624764A1 (en) * 1987-12-16 1989-06-23 Robatel Slpi CENTRIFUGAL DECANTER WITH RETRACTABLE FEEDER

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0690456A1 (en) * 1994-07-01 1996-01-03 Abb Atom Ab Method and apparatus for the treatment of aerosols
US8529425B2 (en) 2007-12-07 2013-09-10 Tomoe Engineering Co., Ltd. Horizontal centrifugal separator in which the hermeticity of a casing is improved by using a sealing element having a simple structure

Also Published As

Publication number Publication date
DE69405051D1 (en) 1997-09-25
JPH0712994A (en) 1995-01-17
DE69405051T2 (en) 1998-01-15
FR2706216A1 (en) 1994-12-16
FR2706216B1 (en) 1995-07-21
US5494579A (en) 1996-02-27
EP0628970B1 (en) 1997-08-20

Similar Documents

Publication Publication Date Title
EP0628970B1 (en) Decanter centrifuge for the treatment of nuclear products
FR2460720A1 (en) SAND SEPARATOR FOR THE PREPARATION OF CELLULOSIC PASTE
EP0158544B1 (en) Process for replacing a sleeve inside a pipe, and devices for carrying out this process
FR2808458A1 (en) CONTINUOUS ROTARY FILTERING DEVICE OF A LIQUID SUCH AS A SOLUTION CONTAINING A PRECIPITY
CH669126A5 (en) METHOD FOR DISPOSAL OF PULVERULENT MACHINING WASTE.
FR2747780A1 (en) DEVICE FOR SAMPLING HARMFUL LIQUID SAMPLES, PARTICULARLY CHARGED WITH SOLID PARTICLES
CA2743401C (en) Ring for a hydrostatic and hydrodynamic bearing, hydraulic machine provided with such a ring and method for mounting such a ring on a shaft
EP0019539A1 (en) Method and machines for removing shells from hard-boiled eggs
EP0883731A1 (en) Core sampler
EP1551555A2 (en) Annular centrifugal extractor with embedded stirring rotor
US3145173A (en) Centrifuge having forced solids discharge
FR2684562A1 (en) Apparatus for recycling solvents
EP0054502B1 (en) Bearing arrangement for a centrifuge
FR2711678A1 (en) Method and apparatus for manufacturing a plied yarn.
EP0081180B1 (en) Machine for grooving around a tube, especially during the implantion of that tube on a vessel of a nuclear reactor
EP0428433B1 (en) Device for fixation of upper spider guide plate in a nuclear reactor vessel
FR2627405A1 (en) PROCESS FOR WIREDING METAL, ESPECIALLY ALUMINUM, AND WELDING PRESS FOR IMPLEMENTING THE METHOD
EP0321365B1 (en) Decanter centrifuge with a retractable feeding device
FR2700495A1 (en) Method and device for the preparation of used metal drums in order to facilitate their handling and recycling.
FR2514669A1 (en) Automatic self-cleaning air filter - uses supported vertical bags subject to exterior pressure and cleaned by pulses of reversed air flow
EP0499769B1 (en) Gravimetric concentration process in a jig
FR3103240A1 (en) WHEEL FOR A TURBOMACHINE EPICYCLOIDAL GEAR REDUCER SATELLITE CARRIER
FR2608463A1 (en) Continuous-operation centrifugal dryer (hydroextractor)
WO1994019274A1 (en) Method for removing a viscous material from a transport drum and device therefor
BE645799A (en)

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): DE FR GB

17P Request for examination filed

Effective date: 19950127

17Q First examination report despatched

Effective date: 19951228

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 69405051

Country of ref document: DE

Date of ref document: 19970925

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19971031

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

Ref country code: FR

Payment date: 19990528

Year of fee payment: 6

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

Ref country code: GB

Payment date: 19990618

Year of fee payment: 6

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

Ref country code: DE

Payment date: 19990715

Year of fee payment: 6

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

Ref country code: GB

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

Effective date: 20000602

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20000602

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

Ref country code: FR

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

Effective date: 20010228

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

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

Ref country code: DE

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

Effective date: 20010403