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Expired European patentEurope

Production of calcium-sulfate hemihydrate using waste heat, diluted sulfuric acid and sulfuric salts

EP 0044005 B1 · Applicant: HIS Handels- und Industriebedarf GmbH

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Overview

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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 July 3, 1981 and granted September 26, 1984. A European patent lasts at most 20 years from filing, so its term ended July 3, 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 January 3, 2007.
  • 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.
FiledJuly 3, 1981
PublishedJanuary 20, 1982
GrantedSeptember 26, 1984
Term endedJuly 3, 2001
Application numberEP 81105169
Classification (CPC)C04B11/02 +1 more

Timeline

Timeline From EPO dates

1982198419861988199019921994199619982000Application filedJuly 3, 1981PublishedJan 20, 1982Patent grantedSep 26, 1984Term endedJuly 3, 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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