Granted Patent
Utility
US 4,421,067 · App. 06/415,318
Apparatus and method for soot cleaning in high-pressure heat exchangers
Inventor:
Robert James Krowech
Patented Case
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Granted: Dec 20, 1983
Filed: Sep 7, 1982
Inventor
Robert James Krowech
Assignee (at issue)
Deltak Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.