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Expired European patentEurope

Process and apparatus for the pyrogenic preparation of silicon dioxide

EP 0044903 B1 · Applicant: Degussa Aktiengesellschaft

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed March 21, 1981 and granted May 29, 1985. A European patent lasts at most 20 years from filing, so its term ended March 21, 2001.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by September 21, 2006.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledMarch 21, 1981
PublishedFebruary 3, 1982
GrantedMay 29, 1985
Term endedMarch 21, 2001
Application numberEP 81102147
Classification (CPC)C01B33/183

Timeline

Timeline From EPO dates

1982198419861988199019921994199619982000Application filedMarch 21, 1981PublishedFeb 3, 1982Patent grantedMay 29, 1985Term endedMarch 21, 2001

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

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