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Underground retorting for secondary oil recovery

US 2,718,263 A · Inventors: HEILMAN WILLIAM O et al.

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Listed from its USPTO record in Patent Yard's full-term archive. Its claims, description and drawings are in the USPTO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Granted September 20, 1955. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by September 20, 1972.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledFebruary 6, 1952
GrantedSeptember 20, 1955
Term endedSeptember 20, 1972
Application number—
Classification (CPC)E21B43/243 +1 more
Length5 pages

Timeline

Timeline From USPTO dates

1953195519571959196119631965196719691971Application filedFeb 6, 1952Patent grantedSep 20, 1955Term endedSep 20, 1972

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Official USPTO records

Full published documentText and every drawing sheet as a PDF.USPTOFile historyStatus, office actions, notices, fee records and petitions.USPTO Patent CenterPatent Public Search recordSearchable full text and bibliographic data.USPTO

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Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comJustia PatentsFull text, claims and classification.patents.justia.comFreePatentsOnlineFull text and PDF.freepatentsonline.comEspacenetForeign family and legal status.European Patent Office

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