EP0094825A2 - Convective drying - Google Patents

Convective drying Download PDF

Info

Publication number
EP0094825A2
EP0094825A2 EP83302767A EP83302767A EP0094825A2 EP 0094825 A2 EP0094825 A2 EP 0094825A2 EP 83302767 A EP83302767 A EP 83302767A EP 83302767 A EP83302767 A EP 83302767A EP 0094825 A2 EP0094825 A2 EP 0094825A2
Authority
EP
European Patent Office
Prior art keywords
electrodes
radio frequency
dryer
nozzles
convective
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
EP83302767A
Other languages
German (de)
French (fr)
Other versions
EP0094825B1 (en
EP0094825A3 (en
Inventor
Peter Leslie Jones
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.)
Cessione ea Technology Ltd
Original Assignee
Electricity Council
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 Electricity Council filed Critical Electricity Council
Priority to AT83302767T priority Critical patent/ATE35454T1/en
Publication of EP0094825A2 publication Critical patent/EP0094825A2/en
Publication of EP0094825A3 publication Critical patent/EP0094825A3/en
Application granted granted Critical
Publication of EP0094825B1 publication Critical patent/EP0094825B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
    • F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/32—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action
    • F26B3/34—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects
    • F26B3/343—Drying solid materials or objects by processes involving the application of heat by development of heat within the materials or objects to be dried, e.g. by fermentation or other microbiological action by using electrical effects in combination with convection

Definitions

  • the invention relates to methods of and apparatus for convective drying of materials in which heated air or other gas is directed onto the material to be dried.
  • Such a dryer may comprise a plurality of nozzles or jets for. the heated air or gas and the material is passed between or below these jets or nozzles.
  • the material may be a web, e.g. of fabric, which is passed between the jets or nozzles or it may be material, e.g. sheet material or pieces, which is carried on a belt or other carrier between or below the jets or nozzles.
  • these jets or nozzles are formed of electrically conductive material and are arranged to constitute the electrodes or at least some of the electrodes of radio frequency heating means providing a radio frequency field in the region through which the material to be dried is passed.
  • the radio frequency heating means heats the material internally so that heat transfer to the material occurs within the body of the material as well as on the surface thereof where the convective heating is effected.
  • the internal heating of the material causes moisture from the interior to move to the surface of the material, keeping this surface wet and so allowing higher air (or other gas) temperatures to be used than would be the case in the absence of radio frequency heating.
  • the overall drying efficiency is increased, resulting in increased drying speeds and reduced dryer length and may give improved material quality.
  • the invention furthermore includes within its scope a method of drying a material comprising the steps of passing the material through a heated gas stream and simultaneously subjecting the material to a radio frequency field.
  • the material to be dried would usually be electrically non-conductive and thus the radio frequency field would give dielectric heating.
  • the frequency of operation may be chosen in accordance with known practice for dielectric heating.
  • the radio frequency heating may be "stray field” heating in which the electrodes are all arranged beneath the material to be dried.
  • Preferably however “through field” heating is effected using electrodes above the material co-operating with electrodes below the material.
  • the electrodes in such an arrangement preferably are staggered, that is to say a upper electrodes are arranged above spaces between lower electrodes.
  • the major part of the heat input is applied to heating the air or other gas for the convective drying.
  • the amount of power input to the radio frequency heating is between 1/5th and 1/10th of the.total energy input to the dryer.
  • the jets or nozzles for the heated gas may be arranged, in the known way, to form an air flotation device to support the material to be dried. Such an arrangement may conveniently be used for the drying of webs of material.
  • jets or nozzles both above and below the belt, these jets or nozzles being arranged to form electrodes of a "through field" radio frequency heating system.
  • Such an arrangement may conveniently be applied to the drying of sheet materials such as insulation board and plaster board and to other products such as pulp or fibre mouldings.
  • the technique may also be applied to the baking or processing of a wide range of foodstuffs.
  • the material to be dried is shown diagrammatically as a web 10 of electrically non-conductive material which is moved through the dryer in the direction of the arrow A.
  • a web 10 of electrically non-conductive material which is moved through the dryer in the direction of the arrow A.
  • nozzle boxes 11 each constituting an electrode and each having one or more nozzles 12 for directing heated air onto the web.
  • nozzle boxes 13 these nozzle boxes constituting electrodes and having nozzles 14 to direct heated air onto the web.
  • the nozzle boxes 11 are connected as shown at 15 in parallel to one output terminal 16 of a radio frequency generator 17.
  • the nozzle boxes 13 are connected electrically in parallel as shown at 18 to the second terminal 19 of the radio frequency generator.
  • the various nozzles are fed from an air heater 20 in which the heat may be generated from any convenient fuel source for example, gas, oil, steam banks or electrical resistance heaters.
  • the resonant frequency of the output circuit of the radio frequency heater may be made controllable, as is well known in radio frequency heating, e.g. by the use of adjustable capacitors or inductors in the radio frequency circuit.
  • the positional arrangement of the electrodes in which the upper electrodes 11 are staggered with respect to the lower electrodes 13, provides a "through field" radio frequency heating system which permits relatively thick materials to be processed without substantial differential heating occurring.
  • the ratio of the vertical spacing between the upper and lower electrodes (as shown at a in the figure) to the horizontal spacing (as shown at b in the figure) is chosen to suit the particular material being dried, this ratio being chosen in accordance with the thickness of the material,_ the loss factor and the vapour diffusion characteristics through the material, as well as to give optimum web stability and convective heat transfer.
  • the radio frequency heating heats the material internally and so tends to drive moisture towards the surface of the material thereby keeping the surface of the material wet. This allows the drying to take place at a much higher air temperature than would be possible if there was no radio frequency heating and hence gives an improved drying efficiency and increased drying speeds.
  • the major part of the energy input to the system is into the air heaters.
  • the amount of energy provided by the radio frequency heating is typically between 1/5th and 1/10th of the total energy input to the dryer.
  • the electrodes and nozzles are spaced along the length of the web to be dried, they may additionally or alternatively be spaced across the width of the web.

Abstract

A convective dryer has nozzle 11 and 13 for directing hot air from a heater 20 at a material 10 to be heated. The nozzles 11 and 13 are electrically conductive and also constitute electrodes energised by an R.F. generator 17 to generate an R.F. field in the region of the material 10 to augment drying.

Description

  • The invention relates to methods of and apparatus for convective drying of materials in which heated air or other gas is directed onto the material to be dried.
  • Such a dryer may comprise a plurality of nozzles or jets for. the heated air or gas and the material is passed between or below these jets or nozzles. The material may be a web, e.g. of fabric, which is passed between the jets or nozzles or it may be material, e.g. sheet material or pieces, which is carried on a belt or other carrier between or below the jets or nozzles.
  • According to the present invention, in a convective dryer having a plurality of jets or nozzles for directing a heated gas onto material passed over the jets or nozzles, these jets or nozzles are formed of electrically conductive material and are arranged to constitute the electrodes or at least some of the electrodes of radio frequency heating means providing a radio frequency field in the region through which the material to be dried is passed.
  • By this arrangement, the radio frequency heating means heats the material internally so that heat transfer to the material occurs within the body of the material as well as on the surface thereof where the convective heating is effected.
  • The internal heating of the material causes moisture from the interior to move to the surface of the material, keeping this surface wet and so allowing higher air (or other gas) temperatures to be used than would be the case in the absence of radio frequency heating. Thus the overall drying efficiency is increased, resulting in increased drying speeds and reduced dryer length and may give improved material quality.
  • The invention furthermore includes within its scope a method of drying a material comprising the steps of passing the material through a heated gas stream and simultaneously subjecting the material to a radio frequency field.
  • The material to be dried would usually be electrically non-conductive and thus the radio frequency field would give dielectric heating. The frequency of operation may be chosen in accordance with known practice for dielectric heating.
  • The radio frequency heating may be "stray field" heating in which the electrodes are all arranged beneath the material to be dried. Preferably however "through field" heating is effected using electrodes above the material co-operating with electrodes below the material. The electrodes in such an arrangement preferably are staggered, that is to say a upper electrodes are arranged above spaces between lower electrodes.
  • Preferably the major part of the heat input is applied to heating the air or other gas for the convective drying. Typically the amount of power input to the radio frequency heating is between 1/5th and 1/10th of the.total energy input to the dryer.
  • The jets or nozzles for the heated gas may be arranged, in the known way, to form an air flotation device to support the material to be dried. Such an arrangement may conveniently be used for the drying of webs of material.
  • For materials which have to be carried through the dryer on a belt, it is convenient to provide jets or nozzles both above and below the belt, these jets or nozzles being arranged to form electrodes of a "through field" radio frequency heating system. Such an arrangement may conveniently be applied to the drying of sheet materials such as insulation board and plaster board and to other products such as pulp or fibre mouldings. The technique may also be applied to the baking or processing of a wide range of foodstuffs.
  • In the following description of one embodiment of the invention, reference will be made to the accompanying drawing which illustrates diagrammatically in side elevation a dryer for web material.
  • Referring to the drawing, the material to be dried is shown diagrammatically as a web 10 of electrically non-conductive material which is moved through the dryer in the direction of the arrow A. Above the web is a plurality of spaced nozzle boxes 11 each constituting an electrode and each having one or more nozzles 12 for directing heated air onto the web. Similarly, below the web, there are nozzle boxes 13, these nozzle boxes constituting electrodes and having nozzles 14 to direct heated air onto the web.
  • Electrically the nozzle boxes 11 are connected as shown at 15 in parallel to one output terminal 16 of a radio frequency generator 17. The nozzle boxes 13 are connected electrically in parallel as shown at 18 to the second terminal 19 of the radio frequency generator. The various nozzles are fed from an air heater 20 in which the heat may be generated from any convenient fuel source for example, gas, oil, steam banks or electrical resistance heaters.
  • The resonant frequency of the output circuit of the radio frequency heater may be made controllable, as is well known in radio frequency heating, e.g. by the use of adjustable capacitors or inductors in the radio frequency circuit.
  • The positional arrangement of the electrodes in which the upper electrodes 11 are staggered with respect to the lower electrodes 13, provides a "through field" radio frequency heating system which permits relatively thick materials to be processed without substantial differential heating occurring. The ratio of the vertical spacing between the upper and lower electrodes (as shown at a in the figure) to the horizontal spacing (as shown at b in the figure) is chosen to suit the particular material being dried, this ratio being chosen in accordance with the thickness of the material,_ the loss factor and the vapour diffusion characteristics through the material, as well as to give optimum web stability and convective heat transfer. The radio frequency heating heats the material internally and so tends to drive moisture towards the surface of the material thereby keeping the surface of the material wet. This allows the drying to take place at a much higher air temperature than would be possible if there was no radio frequency heating and hence gives an improved drying efficiency and increased drying speeds.
  • The major part of the energy input to the system is into the air heaters. The amount of energy provided by the radio frequency heating is typically between 1/5th and 1/10th of the total energy input to the dryer.
  • Although in the embodiment illustrated, the electrodes and nozzles are spaced along the length of the web to be dried, they may additionally or alternatively be spaced across the width of the web.

Claims (10)

1. A convective dryer having a plurality of jets or nozzles for directing a heated gas onto material passed over the jets or nozzles wherein the jets or nozzles are formed of electrically conductive material and are arranged to constitute the electrodes or at least some of the electrodes of radio frequency heating means providing a radio frequency field in the region through which the material to be dried is passed.
2. A convective dryer as claimed in claim 1 wherein the electrodes are all arranged beneath the material to be dried.
3. A convective dryer as claimed in claim 1 wherein electrodes are provided above the material co-operating with electrodes below the material.
4. A convective dryer as claimed in claim 3 wherein the electrodes are staggered, with upper electrodes arranged-above spaces between lower electrodes.
5. A convective dryer as claimed in any of the preceding claims and wherein the major part of the heat input is applied to heating the gas for the convective drying.
6. A convective dryer as claimed in any of the preceding claims wherein the amount of power input to the radio frequency heating is between 1/5th and 1/10th of the total energy input to the dryer.
7. A convective dryer as claimed in any of the preceding claims. wherein the jets or nozzles for the heated gas are arranged to form an air flotation device to support the material to be dried.
8. A method of drying a material comprising the steps of passing the material through a heated gas stream and simultaneously subjecting the material to a radio frequency field.
9. A method as claimed in claim 8 wherein the major part of the heat input is applied to heating the gas.
10. A method as claimed in claim 8 wherein the power input to the radio frequency heating is between 1/5th and 1/10th of the total energy input to the dryer.
EP83302767A 1982-05-17 1983-05-16 Convective drying Expired EP0094825B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83302767T ATE35454T1 (en) 1982-05-17 1983-05-16 CONVECTION DRYING.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB08214289A GB2123537B (en) 1982-05-17 1982-05-17 Convective drying
GB8214289 1982-05-17

Publications (3)

Publication Number Publication Date
EP0094825A2 true EP0094825A2 (en) 1983-11-23
EP0094825A3 EP0094825A3 (en) 1985-01-16
EP0094825B1 EP0094825B1 (en) 1988-06-29

Family

ID=10530398

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83302767A Expired EP0094825B1 (en) 1982-05-17 1983-05-16 Convective drying

Country Status (10)

Country Link
EP (1) EP0094825B1 (en)
JP (1) JPS5932777A (en)
AT (1) ATE35454T1 (en)
AU (1) AU565203B2 (en)
CA (1) CA1241537A (en)
DE (1) DE3377227D1 (en)
FI (1) FI831711L (en)
GB (1) GB2123537B (en)
NO (1) NO831748L (en)
ZA (1) ZA833515B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0203377A1 (en) * 1985-04-30 1986-12-03 Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 Blow tunnel for drying lacquered work pieces
EP0269358A2 (en) * 1986-11-25 1988-06-01 PETRIE & McNAUGHT LIMITED Drying or baking apparatus
US5659972A (en) * 1995-10-06 1997-08-26 Avery Dennison Corporation Apparatus and method for drying or curing web materials and coatings

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2159613A (en) * 1984-05-31 1985-12-04 Stocker Electronics Company Timber drying
US4638571A (en) * 1986-04-02 1987-01-27 Cook William A Radio frequency nozzle bar dryer
GB8629882D0 (en) * 1986-12-15 1987-01-28 Greenbank Eng Co Ltd Convective drying apparatus

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB914546A (en) * 1959-08-20 1963-01-02 Basf Ag Apparatus for the thermal treatment and/or reaction of materials in a high-frequencyfield
EP0009195A1 (en) * 1978-09-22 1980-04-02 Siemens Aktiengesellschaft Apparatus for guiding a web, in particular a web of paper

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB620956A (en) * 1947-02-04 1949-04-01 P R T Lab Ltd Improvements in or relating to heating and drying by radio frequency currents
GB1236374A (en) * 1967-07-17 1971-06-23 Sericol Group Ltd Improvements in the drying of sheet or web material
FR2089900A5 (en) * 1970-04-23 1972-01-07 Menschner Johanne Textil
GB1424431A (en) * 1973-03-19 1976-02-11 Kanebo Ltd Process and apparatus for drying porous material
GB1486415A (en) * 1974-09-16 1977-09-21 Wira & Mather Method and means for drying objects of or containing textile fibres
GB1556296A (en) * 1978-02-10 1979-11-21 Magnetronics Ltd Apparatus for electromagnetic irradiation of a material web

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB914546A (en) * 1959-08-20 1963-01-02 Basf Ag Apparatus for the thermal treatment and/or reaction of materials in a high-frequencyfield
EP0009195A1 (en) * 1978-09-22 1980-04-02 Siemens Aktiengesellschaft Apparatus for guiding a web, in particular a web of paper

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0203377A1 (en) * 1985-04-30 1986-12-03 Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 Blow tunnel for drying lacquered work pieces
EP0269358A2 (en) * 1986-11-25 1988-06-01 PETRIE & McNAUGHT LIMITED Drying or baking apparatus
EP0269358A3 (en) * 1986-11-25 1989-08-30 PETRIE & McNAUGHT LIMITED Drying or baking apparatus
US5659972A (en) * 1995-10-06 1997-08-26 Avery Dennison Corporation Apparatus and method for drying or curing web materials and coatings
EP0853748A1 (en) * 1995-10-06 1998-07-22 Avery Dennison Corporation Apparatus and method for drying or curing web materials and coatings
US5813134A (en) * 1995-10-06 1998-09-29 Avery Dennison Corporation Apparatus and method for drying or curing web materials and coatings
EP0853748A4 (en) * 1995-10-06 1999-09-15 Avery Dennison Corp Apparatus and method for drying or curing web materials and coatings
US5981022A (en) * 1995-10-06 1999-11-09 Avery Dennison Corporation Apparatus and method for drying or curing web materials and coatings

Also Published As

Publication number Publication date
FI831711A0 (en) 1983-05-16
NO831748L (en) 1983-11-18
CA1241537A (en) 1988-09-06
ATE35454T1 (en) 1988-07-15
FI831711L (en) 1983-11-18
GB2123537B (en) 1985-10-02
EP0094825B1 (en) 1988-06-29
ZA833515B (en) 1984-01-25
JPS5932777A (en) 1984-02-22
EP0094825A3 (en) 1985-01-16
AU565203B2 (en) 1987-09-10
DE3377227D1 (en) 1988-08-04
AU1458083A (en) 1983-11-24
GB2123537A (en) 1984-02-01

Similar Documents

Publication Publication Date Title
US3491457A (en) Microwave drying method and apparatus
US4638571A (en) Radio frequency nozzle bar dryer
US2408434A (en) Method and apparatus for drying materials uniformly throughout their mass
US3701875A (en) H. f. heating apparatus
EP2849533B1 (en) Appliance for drying articles
GB2019543A (en) Drying by Electricity
US3418723A (en) Turbulent drying process
EP0064516B1 (en) A method of carrying out the drying of wooden objects
EP0094825B1 (en) Convective drying
US4257167A (en) Arrangement for supporting a web, especially a paper web
HU209206B (en) Method and apparatus for drying wood-veneer plates and similars
US2483933A (en) Ultra high frequency dielectric heater
US2951139A (en) Paper drier
CA2042010C (en) Radio frequency veneer dryer
US3161480A (en) Dielectrically heated drying apparatus through which the articles to be dried are continuously advanced
EP0272854A2 (en) Convective drying apparatus
US3330932A (en) High frequency dielectric heating process and apparatus
Resch Drying of incense cedar pencil slats by microwave power
CA1038458A (en) Microwave paint dryer
JPH02110283A (en) Tensionless microwave drying device for fabric or sheet type fibrous material
US2960428A (en) Method of treating sheets of ligno cellulose
JPH08303957A (en) High frequency dryer
RU2133934C1 (en) Method of drying of materials
SU1726601A1 (en) Apparatus for liquid and thermal treatment of moving textile material
JPH0542392B2 (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

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

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

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

17P Request for examination filed

Effective date: 19850330

ITF It: translation for a ep patent filed

Owner name: BARZANO' E ZANARDO ROMA S.P.A.

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 IT LI LU NL SE

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

Ref country code: LI

Effective date: 19880629

Ref country code: CH

Effective date: 19880629

Ref country code: AT

Effective date: 19880629

REF Corresponds to:

Ref document number: 35454

Country of ref document: AT

Date of ref document: 19880715

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3377227

Country of ref document: DE

Date of ref document: 19880804

ET Fr: translation filed
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

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

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: 19890531

26N No opposition filed
REG Reference to a national code

Ref country code: FR

Ref legal event code: TP

ITPR It: changes in ownership of a european patent

Owner name: CESSIONE;ELECTRICITY ASSOCIATION SERVICES LIMITED

NLS Nl: assignments of ep-patents

Owner name: ELECTRICITY ASSOCIATION SERVICES LIMITED TE LONDEN

ITTA It: last paid annual fee
REG Reference to a national code

Ref country code: FR

Ref legal event code: TP

NLS Nl: assignments of ep-patents

Owner name: EA TECHNOLOGY LIMITED TE CAPENHURST, GROOT-BRITTAN

EAL Se: european patent in force in sweden

Ref document number: 83302767.5

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

Ref country code: BE

Payment date: 19950426

Year of fee payment: 13

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

Ref country code: SE

Payment date: 19950517

Year of fee payment: 13

ITPR It: changes in ownership of a european patent

Owner name: CESSIONE;EA TECHNOLOGY LIMITED

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

Ref country code: SE

Effective date: 19960517

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

Ref country code: BE

Effective date: 19960531

BERE Be: lapsed

Owner name: EA TECHNOLOGY LTD

Effective date: 19960531

EUG Se: european patent has lapsed

Ref document number: 83302767.5

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

Ref country code: DE

Payment date: 20020515

Year of fee payment: 20

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

Ref country code: FR

Payment date: 20020523

Year of fee payment: 20

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

Ref country code: NL

Payment date: 20020531

Year of fee payment: 20

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

Ref country code: NL

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20030516

NLV7 Nl: ceased due to reaching the maximum lifetime of a patent

Effective date: 20030516