EP0051540B1 - Procédé de traitement thermique de particules solides fines - Google Patents

Procédé de traitement thermique de particules solides fines Download PDF

Info

Publication number
EP0051540B1
EP0051540B1 EP81401731A EP81401731A EP0051540B1 EP 0051540 B1 EP0051540 B1 EP 0051540B1 EP 81401731 A EP81401731 A EP 81401731A EP 81401731 A EP81401731 A EP 81401731A EP 0051540 B1 EP0051540 B1 EP 0051540B1
Authority
EP
European Patent Office
Prior art keywords
particles
gaseous stream
heavy
light
heated
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
EP81401731A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0051540A1 (fr
Inventor
Maurice A. Bergougnou
Georges Meunier
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.)
Tunzini Nessi Entreprises d'Equipements SA TNEE
Original Assignee
Tunzini Nessi Entreprises d'Equipements SA TNEE
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 Tunzini Nessi Entreprises d'Equipements SA TNEE filed Critical Tunzini Nessi Entreprises d'Equipements SA TNEE
Priority to AT81401731T priority Critical patent/ATE5613T1/de
Publication of EP0051540A1 publication Critical patent/EP0051540A1/fr
Application granted granted Critical
Publication of EP0051540B1 publication Critical patent/EP0051540B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
    • F28C3/00—Other direct-contact heat-exchange apparatus
    • F28C3/10—Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material
    • F28C3/12—Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material the heat-exchange medium being a particulate material and a gas, vapour, or liquid
    • F28C3/14—Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material the heat-exchange medium being a particulate material and a gas, vapour, or liquid the particulate material moving by gravity, e.g. down a tube
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D19/00—Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium
    • F28D19/02—Regenerative heat-exchange apparatus in which the intermediate heat-transfer medium or body is moved successively into contact with each heat-exchange medium using granular particles

Definitions

  • the invention relates to a method of heat treatment of fine or light solid particles. It relates more particularly to a process for the thermal treatment of fine or light solid particles using dripping gas-solid exchangers.
  • the present invention performs these same heat treatments in relatively small devices, easy to use and good thermal efficiency. It uses dripping gas / solid exchangers, which seemed a priori unusable for these materials, and performs a double thermal transfer, carried out by means of a flow of recyclable solid particles, the density and particle size of which have been chosen so appropriate.
  • these light particles that is to say of low terminal speed of free fall (due to their particle size and / or their density) are transported pneumatically by the gaseous current from bottom to top, for example in a packed column traversed against the current, in runoff, by a flow of "heavy" solid particles (of particle size, density and mechanical characteristics chosen).
  • the light particles are introduced cold and the heavy particles hot, there is thus a heating of the light particles and a simultaneous cooling of the heavy particles.
  • the carrier gas heats up at the same time as the light particles it carries.
  • the heavy particles, recovered cold, are then heated again in a second exchanger, and recycled, that is to say reintroduced into the first exchanger, which makes it possible to continuously carry out the heat transfer leading to the heating of the particles. light.
  • the present invention obviously makes it possible, in a similar manner, to obtain the cooling of hot light particles using heavy recyclable cold particles.
  • the heavy recycled particles will preferably be chosen from materials resistant to attrition, of high density and of approximately spherical shape: sand beads of molten zircon or glass-ceramic, with a particle size of 1 to 2 mm and a density of 2.5 to 3.8 have given good results, these values not being limiting.
  • figs. 1 to 4 represent various variants of installations for implementing the method according to the present invention.
  • the installation shown in fig. 1 is intended to cool hot light particles, such as cement or alumina having undergone a calcination treatment in a rotating tube or a fluidized bed for example.
  • the hot fine particles (at a temperature of, for example, between 700 and 1100 ° C.) are collected in a hopper 1 and taken up by a rotary airlock, a worm, a vibrating corridor or any other system of dis volumetric contribution 2 to supply a venturi system 3 responsible for ensuring pneumatic transport by means of a current of hot air coming from a recovery device which will be described later.
  • the hot fines dispersed in the hot air are then brought through a conduit 4 to the lower part of an exchanger 5.
  • This consists of a cylindrical (or cylindrical-conical) container lined with horizontal stages of filling such as rings, gratings or profiles.
  • the hot air, charged with light fines rises against a flow of heavy particles chosen so that their limit speed of free fall is of the order of 10 to 100 times that of "fines".
  • a methodical type heat exchange takes place between these two flows during their displacement, against the current, and in direct contact.
  • the fines and their carrier air once cooled, escape to the upper part of the exchanger 5 through a conduit 6 and are collected in a cyclone 7 which separates them.
  • the cooled fines are delivered to the base of the cyclone via a rotary airlock 8, while the carrier air, also cooled, escapes to the atmosphere through an exhaust fan 9 possibly after filtration.
  • the heavy particles thus heated are then collected in the conical hopper 11 forming the bottom of the exchanger 5, then they reach a rotary distributor 12 of the same type as the distributor 10, but possibly constructed of refractory alloy if necessary and disposed at the upper part of a second exchanger 13.
  • the distributor 12 also acts as an airlock between the exchanger 5 already described and the second exchanger 13.
  • the heavy particles trickle through the exchanger 13, constituted in a similar way to the exchanger 5, and meet there against the current a flow of cold air, coming from the base, which gradually heats up there.
  • the heavy particles are collected in a fluidized siphon 14, the bottom 15 of which, provided with a fluidization grid, receives air through a conduit 16, and is evacuated in overflow by a conduit 17 to a storage tank 18 before being recycled by an elevator 19, for example with buckets, to the distributor 10.
  • the cold air is brought to the lower part of the exchanger 13 by a conduit 20 under the action of a fan 21 and heats up there in contact with the hot heavy particles.
  • this heated air is divided into two fractions: one of them is used to ensure the pneumatic transport of hot fines at the entrance of Venri 3 and the other can be, for example, to supply the burners of a calciner or for any other use: drying of the products at the start of the manufacturing cycle, etc.
  • the mass flow rates per unit area of the exchanger can be pushed to very high levels, from l '' from 5 to 10 T / h per m2 which allows relatively moderate sections of apparatus.
  • the installation shown in fig. 2 is intended for reheating light particles, for example before their introduction into a calcination oven, or even with a view to their drying (internal humidity).
  • the cold light particles stored in a hopper 22 are admitted via a device 23 for volumetric distribution at a controlled flow rate in a venturi 24 responsible for ensuring their dispersion and their transport by a conduit 25 in an air flow cold from a fan 26. They penetrate the lower part of an exchanger 27 comprising packing stages of the type similar to that which has been described for FIG. 1.
  • the air charged with light particles rises to meet a flow of hot heavy particles which descend through the exchanger.
  • the heat exchange between these two flows takes place from stage to stage, against the current and in direct contact.
  • the fines and their heated carrier air escape the upper part of the exchanger 27 by a conduit 28 to a cyclone separator 29.
  • the fines are collected at the base of the cyclone via a rotary airlock 30 and can then be directed, suitably preheated, to the device ensuring their subsequent treatment, for example a calciner, while the carrier air, also hot, is taken up by a conduit 31 to be reused as indicated below.
  • the path of the heavy particles is as follows: collected cold at the bottom of the exchanger 27 in a fluidized siphon 32, similar to the siphon 14, of FIG. 1, which separates, by elutriation, the few fine particles which could have been entrained, they are discharged through a conduit 33 into a storage tank 34, and are taken up by an elevator 35, for example with buckets, to be sent to the atmospheric separation rotary distributor 36 which distributes them to the upper part of the exchanger 37, similar to the exchanger 27. They are heated there against the current by a hot gas flow introduced through a conduit 38 to the part bottom of the exchanger 37, for example from a calciner and the air heated in the exchanger 27, air which has been taken up by the conduit 31, as indicated above.
  • the heavy particles are collected hot, at the bottom of the exchanger 37, to come directly to feed the rotary distributor with separation of atmosphere 39 which feeds the exchanger 27, while the cooled gases escape at the top of the exchanger 37 are discharged to the atmosphere by a fan 40 after passing through a cyclone separator 41.
  • the circulation of hot gases in the exchanger 37 of FIG. 2 is provided by the fan 40 located at the discharge of cold air at the top of the exchanger.
  • the lifting of heavy particles for recycling is always carried out at low temperature, allowing the empbi of a simple device, such as a bucket elevator.
  • the installation shown in fig. 3 is an installation intended for a relatively brief treatment of light particles, such as a "flash" calcination or drying, that is to say a duration of the order of a second, therefore much shorter than what was aimed with the installations of fig. 1 and 2.
  • the cold fine particles to be treated stored in a hopper 42 are admitted via a device 43 for volumetric distribution in a venturi system 44 responsible for their dispersion and their transport by a duct 45 in a flow of cold air carrier coming from a fan 46. They penetrate the lower part of the exchanger 47, similar to the exchangers 13 and 27, to meet heavy and hot particles falling in rain.
  • the mixture of treated fines and hot carrier gases enters the base of a second exchanger 49 constituted like the previous ones.
  • the mixture there meets, against the current, a flow of heavy particles introduced cold at the upper part of the exchanger 49.
  • the cooled treated fines are evacuated by a conduit 50 and separated from their carrier gases in a cyclone 51.
  • the fines are removed by a rotary airlock 52 and the gases are sent to the atmosphere, possibly by means of an extractor fan 53.
  • the closed circuit route for heavy particles is similar to the previous case. They are introduced cold at the upper part of the exchanger 49 by the rotary distributor 54 with airtightness. Heated during the passage of the exchanger 49, they are transferred directly by the distributor 55 to the upper part of the exchanger 47, from which they are evacuated by the siphon 56 to a storage tank 57 and the recycling elevator 58.
  • the installation shown in fig. 4 is a simplified fine treatment installation, usable when said treatment requires only a few fractions of a second, for example when the fines are polluted with combustible particles, or sensitive to heat.
  • the fines to be treated are transported pneumatically as above and admitted to the base of an exchanger 59 which has three sections.
  • the fines gradually heat up to meet hot heavy particles which descend.
  • the exchanger which is a combustion zone, they are brought into contact with hot gases coming from burners 62, annular for example, which allows them to reach the desired temperature, for example 800 ° C. .
  • the fines gradually cool in contact with the cold heavy particles which flow down in rain from the distributor 64 Finally, they are evacuated by a conductor 65 and separated by a cyclone 66 from their carrier air, and finally evacuated by the rotary airlock 67.
  • the heavy particles flow from the distributor 64, through the exchange assembly 63, 61, 60, then, evacuated by the siphon 68, they are recycled by the elevator 69, after intermediate storage in the tank 70.
  • the movement of the gases through the exchange column is ensured by a fan 71 supplying the venturi 72 for introducing fines.
  • the invention which is applicable in the most diverse industries having to deal with large tonnages of fine solids, can advantageously be used for the calcination of hydrated alumina , both for the heating of hydrated product and for the cooling of the calcined product.
  • a particle size of the alumina of 50 to 80, am corresponding to a terminal speed of free fall of the order of 10 to 50 cm / s, using, for example, as recyclable heavy particles, zircon beads 1.2 to 1.6 mm in diameter, with an average terminal speed of the order of 10 m / s.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Glanulating (AREA)
  • Control Of Heat Treatment Processes (AREA)
  • Control Of Temperature (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Recrystallisation Techniques (AREA)
EP81401731A 1980-11-05 1981-10-29 Procédé de traitement thermique de particules solides fines Expired EP0051540B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81401731T ATE5613T1 (de) 1980-11-05 1981-10-29 Verfahren fuer die thermische behandlung sehr kleiner fester partikel.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8023570 1980-11-05
FR8023570A FR2493495B1 (fr) 1980-11-05 1980-11-05 Procede de traitement thermique de particules solides fines a l'aide d'echangeurs gaz-solides ruisselants

Publications (2)

Publication Number Publication Date
EP0051540A1 EP0051540A1 (fr) 1982-05-12
EP0051540B1 true EP0051540B1 (fr) 1983-12-14

Family

ID=9247682

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81401731A Expired EP0051540B1 (fr) 1980-11-05 1981-10-29 Procédé de traitement thermique de particules solides fines

Country Status (12)

Country Link
US (1) US4450895A (enrdf_load_stackoverflow)
EP (1) EP0051540B1 (enrdf_load_stackoverflow)
JP (1) JPS57136929A (enrdf_load_stackoverflow)
AT (1) ATE5613T1 (enrdf_load_stackoverflow)
AU (1) AU545520B2 (enrdf_load_stackoverflow)
BR (1) BR8107157A (enrdf_load_stackoverflow)
CA (1) CA1187282A (enrdf_load_stackoverflow)
DE (1) DE3161655D1 (enrdf_load_stackoverflow)
ES (1) ES8207636A1 (enrdf_load_stackoverflow)
FR (1) FR2493495B1 (enrdf_load_stackoverflow)
OA (1) OA06936A (enrdf_load_stackoverflow)
ZA (1) ZA817459B (enrdf_load_stackoverflow)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2554221B1 (fr) * 1983-08-04 1986-01-03 Tunzini Nessi Entreprises Equi Elements de garnissage pour dispositif d'echange, notamment thermique, par contre-courant entre des particules solides et un courant gazeux
NL191304C (nl) * 1992-07-15 1995-05-16 Cooeperatie Abc B A Werkwijze en inrichting voor het koelen van voeder.
US6263958B1 (en) 1998-02-23 2001-07-24 William H. Fleishman Heat exchangers that contain and utilize fluidized small solid particles
US6843785B2 (en) 2001-08-20 2005-01-18 Kimberly-Clark Worldwide, Inc. System and method for attaching absorbent articles
CN2684967Y (zh) * 2004-01-07 2005-03-16 朱旭东 铸造用砂加热装置
US20090114567A1 (en) * 2007-11-07 2009-05-07 Maxwell James F Cracking hydrocarbonaceous materials with heating bodies
CN111136826A (zh) * 2020-01-15 2020-05-12 广东宏工物料自动化系统有限公司 一种颗粒冷却装置

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2739994A (en) * 1952-04-21 1956-03-27 Union Oil Co Acetylene process
US3051466A (en) * 1956-01-03 1962-08-28 Socony Mobil Oil Co Inc Method for heating granular solids
FR1201476A (fr) * 1957-05-16 1959-12-30 Air Preheater échangeur de chaleur pour granules
US3029484A (en) * 1960-01-04 1962-04-17 Kutny Istvan Sand regenerating and cupola preheating apparatus
FR1469109A (fr) * 1965-12-27 1967-02-10 Saint Gobain Produit intermédiaire pour la fabrication du verre et autres silicates, et procédé et appareillages pour sa fabrication
DE1601146A1 (de) * 1967-12-22 1971-02-04 Siemens Ag Verfahren und Anordnung zur Zu- und/oder Ableitung von Masseteilchen bei Waermetauschern
US3630501A (en) * 1970-08-21 1971-12-28 Air Prod & Chem Thermal treatment of powder
US3831668A (en) * 1972-05-17 1974-08-27 P Weissenburg Tower type heat exchangers for heat interchange between gases heated to different temperatures
FR2429046A1 (fr) * 1978-06-19 1980-01-18 Saint Gobain Appareil de distribution de particules solides
FR2452689A1 (fr) * 1979-03-27 1980-10-24 Saint Gobain Procede de recuperation de chaleur sur des fumees

Also Published As

Publication number Publication date
ES506851A0 (es) 1982-10-01
OA06936A (fr) 1983-07-31
CA1187282A (fr) 1985-05-21
US4450895A (en) 1984-05-29
AU7709581A (en) 1982-05-13
FR2493495B1 (fr) 1985-06-28
ES8207636A1 (es) 1982-10-01
JPS57136929A (en) 1982-08-24
ZA817459B (en) 1982-10-27
ATE5613T1 (de) 1983-12-15
JPH0210692B2 (enrdf_load_stackoverflow) 1990-03-09
AU545520B2 (en) 1985-07-18
DE3161655D1 (en) 1984-01-19
BR8107157A (pt) 1982-07-20
FR2493495A1 (fr) 1982-05-07
EP0051540A1 (fr) 1982-05-12

Similar Documents

Publication Publication Date Title
US9359556B2 (en) Biomass torrefaction system and method
FR2563118A1 (fr) Procede et installation de traitement de matiere en lit fluidise circulant
EP0051540B1 (fr) Procédé de traitement thermique de particules solides fines
HUP0600661A2 (en) Reactor and apparatus for the pyrolysis of waste materials, mainly tyres
US4280415A (en) Method and apparatus for drying and processing moisture-containing solids
EP0016713B1 (fr) Procédé de récupération de chaleur sur un courant gazeux chaud et dispositif de mise en oeuvre
FR2818918A1 (fr) Procede et dispositif d'elimination des elements volatifs nefastes, notamment chlorures et/ou sulfates, contenus dans un courant de fumees.
EP0485255B1 (fr) Procédé et dispositif de production d'un combustible solide à partir de déchets combustibles
EP0125973B2 (fr) Installation de traitement thermique de minéraux sous forme pulvérulente
JPH02293516A (ja) 灰分級機・冷却器・燃焼器
FR2489295A1 (fr) Procede et appareil pour prechauffer des matieres pulverulentes avant leur introduction dans un four de fusion
EP0068943A1 (fr) Dispositif de récupération de l'énergie contenue sous forme de chaleur dans les laitiers
EP0044259B1 (fr) Procédé d'épuration des gaz et installation pour sa mise en oeuvre
CA1040855A (fr) Echangeur et procede pour transferer la chaleur entre gaz caloporteur et materiau pulverulent fluidise
EP0009455B1 (fr) Dispositif perfectionné d'échange thermique entre des particules solides et un courant gazeux
EP0491611A1 (fr) Procédé de traitement de fumées de silice en vue de leur blanchiment, et dispositif de mise en oeuvre du procédé
FR2524628A1 (fr) Procede et dispositif pour recuperer de la chaleur de particules solides
SU748099A1 (ru) Способ термообработки дисперсных материалов и установка дл его осуществлени
EP0498731A1 (fr) Procédé et installation pour le traitement thermique de minéraux sous forme pulvérulente
WO1987005687A1 (fr) Echangeur de chaleur gaz-gaz
FR2763341A1 (fr) Procede et installation de traitement thermique de dechets urbains, ou de produits similaires, par gazeification et fusion des residus
HK40049987A (en) Biomass torrefaction system and method
FR2507207A1 (fr) Dispositif de recuperation de l'energie contenue sous forme de chaleur dans les laitiers
FR2644565A2 (fr) Perfectionnements a un procede et a un dispositif de deshydratation d'un mineral pulverulent, notamment pour la fabrication de platre
FR2702392A1 (fr) Procédé et dispositif de régénération d'absorbant régénérables.

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 BE CH DE FR GB IT LU NL SE

17P Request for examination filed

Effective date: 19821029

ITF It: translation for a ep patent filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

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

REF Corresponds to:

Ref document number: 5613

Country of ref document: AT

Date of ref document: 19831215

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3161655

Country of ref document: DE

Date of ref document: 19840119

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: FR

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

Effective date: 19850628

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

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: SE

Payment date: 19920904

Year of fee payment: 12

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

Ref country code: GB

Payment date: 19920916

Year of fee payment: 12

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

Ref country code: BE

Payment date: 19920924

Year of fee payment: 12

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

Ref country code: LU

Payment date: 19921001

Year of fee payment: 12

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

Ref country code: AT

Payment date: 19921012

Year of fee payment: 12

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

Ref country code: CH

Payment date: 19921028

Year of fee payment: 12

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

Ref country code: NL

Payment date: 19921031

Year of fee payment: 12

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

Ref country code: DE

Payment date: 19921215

Year of fee payment: 12

EPTA Lu: 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: 19931029

Ref country code: GB

Effective date: 19931029

Ref country code: AT

Effective date: 19931029

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

Ref country code: SE

Effective date: 19931030

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

Ref country code: LI

Effective date: 19931031

Ref country code: CH

Effective date: 19931031

Ref country code: BE

Effective date: 19931031

BERE Be: lapsed

Owner name: TUNZINI-NESSI ENTREPRISES D'EQUIPEMENTS

Effective date: 19931031

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

Ref country code: NL

Effective date: 19940501

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19931029

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: 19940701

EUG Se: european patent has lapsed

Ref document number: 81401731.5

Effective date: 19940510