EP0074633A2 - Procédé de fonctionnement d'un broyeur à billes et broyeur à billes correspondant - Google Patents

Procédé de fonctionnement d'un broyeur à billes et broyeur à billes correspondant Download PDF

Info

Publication number
EP0074633A2
EP0074633A2 EP82108344A EP82108344A EP0074633A2 EP 0074633 A2 EP0074633 A2 EP 0074633A2 EP 82108344 A EP82108344 A EP 82108344A EP 82108344 A EP82108344 A EP 82108344A EP 0074633 A2 EP0074633 A2 EP 0074633A2
Authority
EP
European Patent Office
Prior art keywords
grinding
ball mill
ball
grinding chamber
balls
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
EP82108344A
Other languages
German (de)
English (en)
Other versions
EP0074633A3 (en
EP0074633B1 (fr
Inventor
Hermann Schmid
Waldemar Thum
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.)
Netzsch Feinmahltechnik GmbH
Original Assignee
Netzsch Feinmahltechnik GmbH
Boehringer Mannheim GmbH
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 Netzsch Feinmahltechnik GmbH, Boehringer Mannheim GmbH filed Critical Netzsch Feinmahltechnik GmbH
Priority to AT82108344T priority Critical patent/ATE28132T1/de
Publication of EP0074633A2 publication Critical patent/EP0074633A2/fr
Publication of EP0074633A3 publication Critical patent/EP0074633A3/de
Application granted granted Critical
Publication of EP0074633B1 publication Critical patent/EP0074633B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/16—Mills in which a fixed container houses stirring means tumbling the charge

Definitions

  • the invention relates to a method for operating a ball mill, in particular for the digestion of biomass, in which the ground material is fed to a grinding chamber containing grinding balls and is ground in the grinding chamber by the rotary movement of at least one rotating grinding body and the resulting movement of the grinding balls.
  • the invention further relates to a ball mill which is particularly suitable for carrying out the method and has a grinding container surrounding a grinding chamber in which at least one grinding body which is rotatable relative to the housing is provided.
  • Ball mills have become increasingly important in a number of industrial processes in recent years.
  • An example of this is the paint industry, where it is particularly important to distribute the pigments in the paints as evenly as possible in order to achieve a good dispersion effect.
  • ball mills Another example of the advantageous use of ball mills is the disintegration of biomass from fermentative processes for the production of enzymes in biochemical plants.
  • the effects of ball mills in general and in particular the digestion of biomass are influenced by a number of different parameters. For a given mill size, this includes in particular the stirring speed, the throughput and the size of the grinding balls used, which generally consist of glass, metal or aluminum oxide.
  • the gap width between the grinding element and the grinding container is also important for the grinding effect.
  • a split ball mill is therefore proposed, in which the gap width can be changed in that the distance between the grinding element and grinding container is fixed by means of an interchangeable spacer ring, which can be exchanged between the grinding processes by the gap width adapt to the respective requirements.
  • degree of ball filling is generally defined as the ratio between the actually used and the maximum possible ball filling quantity.
  • degree of ball filling generally leads to an improvement in the grinding effect.
  • increasing the degree of ball filling also causes problems, that set limits.
  • the wear on the mill and on the balls increases with the degree of filling.
  • Energy consumption increases because the grinder rotates harder.
  • the corresponding increase in the frictional heat in the ball mill which can lead to cooling problems.
  • an optimal digestion can be achieved at which a maximum digestion is achieved, but at the same time the cells are not damaged so much that the subsequent processing is thereby made more difficult.
  • the degree of filling can be determined before the start of a grinding process by filling in a precisely defined amount of balls.
  • this degree of filling is not retained during the grinding process. Rather, it changes due to the wear of the balls and the wall and stirring parts in contact with them. In a ten-hour long-term test, wear of 2.5% was found, for example. On the one hand, this changes the grinding behavior of the ball mill during the grinding process.
  • the object of the present invention is therefore to provide a method for operating a ball mill and a corresponding ball mill with which a uniform and optimized grinding action is achieved during the entire grinding process.
  • This object is achieved in a method of the type mentioned at the outset by regulating the degree of ball filling in the grinding chamber during the grinding process in order to adapt to the respective operating conditions.
  • the device according to the invention of the type mentioned at the outset is characterized by means by which the degree of ball filling in the grinding chamber is controlled during operation of the ball mill and can be changed continuously.
  • the regulation of the degree of filling can, as in the example described above, be designed so that the degree of filling is varied during the operation of the ball mill. According to a particularly preferred embodiment of the method according to the invention, however, the ball mill is operated in such a way that the degree of ball filling is kept essentially constant during most of the grinding process.
  • the area of optimal ball filling in particular in the disintegration of biomass, is relatively narrow. For example, a change in the ball filling level of 5 can result in a 20% change in the enzyme content of the product emerging from the ball mill.
  • the degree of ball filling can be controlled manually. However, it is particularly preferably carried out automatically, with the power according to a preferred embodiment Inclusion of the ball mill motor is used as a measure for controlling the degree of ball filling. It has been found that the load on the motor and thus its power consumption depends very much on the degree of ball filling. With a certain ball mill and a certain type of regrind (and otherwise the same boundary conditions as temperature etc.), the current consumption of the motor can be clearly assigned to the ball filling level. The current consumption fluctuates, for example, by 20% in the limit range which is essential for an optimal grinding effect in a particular ball mill if the ball filling is changed by only 1%. On the basis of this knowledge, it is sufficient to determine the power consumption of the motor corresponding to a certain degree of filling for a specific application, in order then to use this value as a setpoint for keeping the ball filling degree constant.
  • the control of the degree of ball filling according to the invention can be accomplished by adding or removing grinding balls during the grinding process.
  • Balls can be added in relatively small quantities, so that sensitive dosing is possible.
  • a removal of balls must be provided, in particular, if operating states can occur in which the degree of ball filling, for example due to momentary overloading of the machine, is to be reduced relatively quickly. It is particularly advantageous if the device for removing balls from the same control device. how to control the addition of balls, which enables fast and accurate control of the ball filling level according to the respective operating conditions.
  • Another preferred method proposal is to be used in particular in connection with ball mills specially designed for this purpose and proposes to control the volume of the grinding chamber during the grinding process in such a way that the desired control of the degree of ball filling is achieved.
  • Such a solution allows a particularly quick reaction to the prevailing conditions by a correspondingly rapid change in the grinding chamber volume and thus the degree of filling.
  • FIG. 1 shows the essential parts of a ball mill 10, the parts which are not essential for the invention, such as the machine stand, the drive motor and the operating parts, being omitted in the cross section shown for reasons of clarity.
  • the part shown consists essentially of the grinding container 12, which is designed in the ball mill shown here as a circular cylinder, which is closed with a base plate 14 on one side. On the side of the grinding container 12 opposite the base plate there is the grinding container end on the motor side, which in its entirety is provided with the reference number 16. It essentially consists of a grinding chamber cover 18 which is screwed via a connecting flange 20 to a corresponding flange 22 with screws not shown in the drawing. A seal 24 is located between the two flanges.
  • a shaft bushing 26 is provided in the center of the grinding chamber cover 18, which is not described in detail here, since it can completely correspond to the bushings used in the known ball mills.
  • the agitator shaft 30 With the drive shaft 28 penetrating the shaft bushing 28, the agitator shaft 30 is connected, which carries agitator disks 32 and can rotate in the grinding container 12 driven by the motor, not shown.
  • the grinding container 12 and the agitator shaft 30 with the stirring disks 32 which can also be generally referred to as entrainment bodies, limit the grinding chamber 34, which in operation contains the grinding balls 36, preferably of about 1-3 mm in diameter, and the material to be ground 38.
  • the grinding container 12 is surrounded by a cooling jacket 40 with two connecting pieces for cooling liquid 44 and 46.
  • a product inlet 48 is provided for feeding the regrind, and the regrind flows after the grinding process from the separation gap 50, the ring channel 52 and the product outlet 54.
  • the separating gap is formed by a separating disk 53 rotating with the agitator shaft 30 and a stationary separating disk 55 and is so narrow that the balls conveyed on with the product cannot pass through it and thus remain in the grinding chamber 34.
  • the ball mill shown here corresponds to one of a number of known ball mill types and other types could also be used for the invention.
  • the peculiarity of the ball mill shown is that there are devices for the continuous and controlled change of the ball filling level in the grinding chamber, a lock device 60 for adding and a drain valve 62 for removing grinding balls being provided in the embodiment shown in FIG.
  • the lock device 60 comprises a storage container 64 which is connected to the grinding chamber 34 via a line 68.
  • the product inlet 48 is connected to line 68.
  • a valve which, in the embodiment shown, is designed as a rubber bellows valve 70 which can be actuated with compressed air via a line 72.
  • the reservoir 64 can be closed tightly with a lid 80.
  • the entire lock device is designed to be pressure-stable to such an extent that it can easily accommodate the pressures occurring in operation in ball mills of, for example, 0.5 bar to 2 bar.
  • the drain valve 62 is connected via a line 82 to the grinding chamber 34 and also has a compressed air line 84 for actuating the rubber bellows not shown in the figure in the valve 62.
  • the compressed air lines 84 and 72 are connected to the same control device 73, which controls the function of the lock device 60 and the drain valve 62.
  • the rubber bellows valve 70 is particularly well suited for this purpose, since it still closes reliably even with the contamination with the grinding balls 36, which contamination can hardly be avoided here.
  • the product inlet 48 can also be provided separately from the line 68.
  • the actuation of the valves 76 and 70 and thus the supply of grinding balls can be carried out both manually and automatically in the device according to the invention.
  • corresponding actuators and an electronic circuit are provided, by means of which the valves are actuated when an increase in the degree of ball filling is necessary. Such devices are known and are not described in detail here.
  • the drain valve 62 is simply opened so that, driven by the pressure prevailing in the ball mill and due to the force of gravity, a small amount of the material to be ground 38 leaves the grinding chamber 34 together with the grinding balls 36 therein . Since such a ball drain is rarely necessary in practical operation, the drain valve 62 can also be omitted. In any case, it only has to be operated rarely, so that the associated loss of regrind can be tolerated.
  • Figure 2 shows another embodiment of the ball mill according to the invention, the corresponding parts with the same reference numerals, but provided with a dash.
  • the main difference compared to the previously described embodiment is that here a variation in the degree of ball filling is not caused by addition or Removal of grinding balls 36 ', but is achieved by variating the volume of the grinding chamber 34'.
  • a bellows 86 is provided on the inner surface of the base plate 14 ', which can consist of a suitable rubber-elastic material or of metal.
  • a cover cover plate 90 is located on the surface of the bellows on the grinding chamber side, which is sealed with the aid of an annular seal 92, for example an O-ring seal, against the inner wall 93 'of the cylindrical part of the grinding container 12.
  • FIG. 3 finally shows a further embodiment of the invention, in which, as in the exemplary embodiment according to FIG. 2, the change in the degree of ball filling is achieved by a corresponding change in the grinding chamber volume.
  • the change in the degree of ball filling is achieved by a corresponding change in the grinding chamber volume.
  • the grinding container 12 "comprises two housing parts 94 and 96, which are sealed off from one another with the aid of an annular seal 98 and are guided concentrically to one another by the guide rings 100.
  • the housing part 96 facing away from the shaft bushing 26 is relative to that by means of hydraulic cylinders 102 Movable housing part 94.
  • the hydraulic rods 104, crossbeams 106 and 108 and corresponding articulated flanges 110 and 112 serve as mechanical connecting parts.
  • the power consumption of the motor under these operating conditions can be used as a yardstick for the ball filling degree.
  • a completely automatic control can then be achieved very easily if one uses the motor current as the actual value for the ball filling level in the manner known in control technology and then changes the ball filling level with the aid of a suitable electronic control and the device according to the invention such that the the current intensity corresponding to the desired ball filling level is reached.
  • a regulation would be desirable, in which in the start-up phase a relatively low degree of ball filling is used, which is then continuously increased to the value corresponding to the optimal digestion, which is then kept constant over the vast majority of a grinding process.

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
  • Disintegrating Or Milling (AREA)
EP82108344A 1981-09-12 1982-09-10 Procédé de fonctionnement d'un broyeur à billes et broyeur à billes correspondant Expired EP0074633B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82108344T ATE28132T1 (de) 1981-09-12 1982-09-10 Verfahren zum betreiben einer kugelmuehle und entsprechende kugelmuehle.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3136323 1981-09-12
DE19813136323 DE3136323A1 (de) 1981-09-12 1981-09-12 Verfahren zum betreiben einer kugelmuehle und entsprechende kugelmuehle

Publications (3)

Publication Number Publication Date
EP0074633A2 true EP0074633A2 (fr) 1983-03-23
EP0074633A3 EP0074633A3 (en) 1985-08-21
EP0074633B1 EP0074633B1 (fr) 1987-07-08

Family

ID=6141561

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82108344A Expired EP0074633B1 (fr) 1981-09-12 1982-09-10 Procédé de fonctionnement d'un broyeur à billes et broyeur à billes correspondant

Country Status (3)

Country Link
EP (1) EP0074633B1 (fr)
AT (1) ATE28132T1 (fr)
DE (2) DE3136323A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0243682A2 (fr) * 1986-05-02 1987-11-04 Draiswerke GmbH Régulation d'un broyeur agitateur
EP0514562A1 (fr) * 1991-05-21 1992-11-25 Inoue Mfg., Inc. Appareil de dispersion continue
US5183215A (en) * 1987-12-03 1993-02-02 Hermann Getzmann Grinding appliance
WO2014187824A1 (fr) 2013-05-21 2014-11-27 Flsmidth A/S Procédés et appareil de surveillance en continu de l'usure dans des circuits de meulage
CN104437816A (zh) * 2014-11-12 2015-03-25 宁夏嘉翔自控技术有限公司 一种金属镁炉料球磨机的黏磨调节装置的电气控制系统
EP2484450B1 (fr) 2011-02-07 2017-05-03 LIPP Mischtechnik GmbH Broyeur agitateur à billes
CN107362871A (zh) * 2017-08-31 2017-11-21 新乡市宏峰矿山设备有限公司 轮带式节能新型球磨机
CN114340796A (zh) * 2019-09-05 2022-04-12 塞泰克单一股东股份公司 液位可控的连续碾磨机
CN117797919A (zh) * 2024-02-19 2024-04-02 浙江艾领创矿业科技有限公司 一种研磨机的加压加球装置及其使用方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH667222A5 (de) * 1985-07-18 1988-09-30 Buehler Ag Geb Verfahren zum regeln einer ruehrwerksmuehle, und regelvorrichtung zur durchfuehrung des verfahrens.
DE3815156A1 (de) * 1987-10-26 1989-11-16 Buehler Ag Geb Ruehrwerksmuehle
DE102007014129A1 (de) * 2007-03-23 2008-09-25 Alstom Technology Ltd. Verfahren zum Betreiben einer Schlagradmühle und Steuergerät zur Steuerung einer Schlagradmühle
DE102013111297A1 (de) * 2013-10-14 2015-04-16 Netzsch-Feinmahltechnik Gmbh Vorzerkleinerungsvorrichtung für eine Kugelmühle oder Rührwerkskugelmühle und Kugelmühle mit Vorzerkleinerungseinrichtung
CN103691529B (zh) * 2013-12-09 2016-03-16 云南冶金新立钛业有限公司 砂磨装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2242174A1 (de) * 1972-08-26 1974-03-07 Netzsch Maschinenfabrik Verfahren und vorrichtung zum feinmahlen und dispergieren
GB2016953A (en) * 1978-03-18 1979-10-03 Fryma Masch Ag Ball mill
FR2433981A1 (fr) * 1978-08-24 1980-03-21 Buehler Ag Geb Broyeur-agitateur a billes equipe d'un circuit de regulation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2242174A1 (de) * 1972-08-26 1974-03-07 Netzsch Maschinenfabrik Verfahren und vorrichtung zum feinmahlen und dispergieren
GB2016953A (en) * 1978-03-18 1979-10-03 Fryma Masch Ag Ball mill
FR2433981A1 (fr) * 1978-08-24 1980-03-21 Buehler Ag Geb Broyeur-agitateur a billes equipe d'un circuit de regulation

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0243682A2 (fr) * 1986-05-02 1987-11-04 Draiswerke GmbH Régulation d'un broyeur agitateur
EP0243682A3 (en) * 1986-05-02 1988-08-17 Draiswerke Gmbh Control of an agitator mill
US5183215A (en) * 1987-12-03 1993-02-02 Hermann Getzmann Grinding appliance
EP0514562A1 (fr) * 1991-05-21 1992-11-25 Inoue Mfg., Inc. Appareil de dispersion continue
EP2484450B1 (fr) 2011-02-07 2017-05-03 LIPP Mischtechnik GmbH Broyeur agitateur à billes
WO2014187824A1 (fr) 2013-05-21 2014-11-27 Flsmidth A/S Procédés et appareil de surveillance en continu de l'usure dans des circuits de meulage
CN104437816A (zh) * 2014-11-12 2015-03-25 宁夏嘉翔自控技术有限公司 一种金属镁炉料球磨机的黏磨调节装置的电气控制系统
CN107362871A (zh) * 2017-08-31 2017-11-21 新乡市宏峰矿山设备有限公司 轮带式节能新型球磨机
CN107362871B (zh) * 2017-08-31 2023-04-07 新乡市宏峰矿山设备有限公司 轮带式节能新型球磨机
CN114340796A (zh) * 2019-09-05 2022-04-12 塞泰克单一股东股份公司 液位可控的连续碾磨机
CN117797919A (zh) * 2024-02-19 2024-04-02 浙江艾领创矿业科技有限公司 一种研磨机的加压加球装置及其使用方法

Also Published As

Publication number Publication date
EP0074633A3 (en) 1985-08-21
EP0074633B1 (fr) 1987-07-08
DE3276685D1 (en) 1987-08-13
ATE28132T1 (de) 1987-07-15
DE3136323A1 (de) 1983-03-31

Similar Documents

Publication Publication Date Title
EP0074633A2 (fr) Procédé de fonctionnement d'un broyeur à billes et broyeur à billes correspondant
DE69013284T2 (de) Verfahren, um einen vorgegebenen Arbeitsdruck auf Unterwasser-Schneideelemente von Granulier-Maschinen konstant zu halten, und Maschine dieser Gattung mit Einrichtung zum Kontrollieren und Einsetzen dieses Arbeitsdruckes.
DE2006390C3 (de) Meßgerät zur stetigen Seherkraftmessung und Bestimmung der physikalischen Eigenschaften von Elastomeren
DE2932783C3 (de) Rührwerkskugelmühle-Regelung
DE2065460B2 (de) Beschickungsvorrichtung für einen Schachtofen
DE3212700C2 (fr)
DE102019107140B4 (de) Düsenanordnung mit Druckreguliervorrichtung sowie Granuliervorrichtung
DE1598595A1 (de) Gerut zur fraktionierung von zellen
DE2650820A1 (de) Stoffloeser
DE3939213C2 (fr)
EP2730338A2 (fr) Dispositif de broyage de substrat et paroi de boîtier pour un tel dispositif
WO2006042491A2 (fr) Melangeur et malaxeur, a un seul arbre, fonctionnant en continu
DE3016785A1 (de) Hydraulisches mehrwalzwerk
EP0019052B1 (fr) Dispositif de prélévement d'échantillons de matières plastiques semi-liquides dans un récipient
DE2832903C2 (de) Rührwerksmühle - Lager
DE102020123521B4 (de) Vorrichtung und Verfahren zum Mischen von zumindest zwei chemisch reaktiven Kunststoffkomponenten
DE2324581C2 (de) Vorrichtung zum Austrag von festen Verunreinigungen bei einem Extruder
DE2924269A1 (de) Vorrichtung zur regelbaren aenderung des stroemungsquerschnittes in einem schneckenextruder
EP0295325A1 (fr) Dispositif de nettoyage pour des récipients utilisés dans des procédés relevant de la biotechnologie et dans des procédés industriels
DE69011536T2 (de) Düse mit veränderbarer öffnung.
DE2747516A1 (de) Vorrichtung zur ueberwachung des bohrerdrucks an bohrwerken
DE102017115080B4 (de) Auslassstutzen und Vorrichtung zur Trennung der Bestandteile einer Feststoffe enthaltenden Flüssigkeit
EP0423458A1 (fr) Procédé pour appliquer un racloir avec une force constante contre le cylindre d'alimentation d'une extrudeuse
DE1175868B (de) Kombinierte Schneckenstrangpresse und Trockner fuer Kunststoffe
CH641059A5 (en) Agitator mill with an electromotively driven agitator mechanism

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

17P Request for examination filed

Effective date: 19820910

AK Designated contracting states

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

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

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

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: NETZSCH-FEINMAHLTECHNIK GMBH

17Q First examination report despatched

Effective date: 19861031

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 FR GB IT LI

REF Corresponds to:

Ref document number: 28132

Country of ref document: AT

Date of ref document: 19870715

Kind code of ref document: T

ITF It: translation for a ep patent filed
REF Corresponds to:

Ref document number: 3276685

Country of ref document: DE

Date of ref document: 19870813

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

Free format text: ORIGINAL CODE: 0009261

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

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

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19890910

Ref country code: AT

Effective date: 19890910

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19900531

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

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

Ref country code: BE

Payment date: 19900928

Year of fee payment: 9

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

Ref country code: CH

Payment date: 19910913

Year of fee payment: 10

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

Ref country code: DE

Payment date: 19910927

Year of fee payment: 10

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

Ref country code: BE

Effective date: 19910930

BERE Be: lapsed

Owner name: NETZSCH-FEINMAHLTECHNIK G.M.B.H.

Effective date: 19910930

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

Ref country code: LI

Effective date: 19920930

Ref country code: CH

Effective date: 19920930

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: 19930602