Granted Patent
Utility
US 4,750,274 · App. 07/007,156
Sludge processing
Inventors:
Andrew Erdman, Jeffrey C. Johnson, Jerry A. Levad
Patented Case
View Patent ↗
Granted: Jun 14, 1988
Filed: Jan 27, 1987
Inventors
Andrew Erdman
Jeffrey C. Johnson
Jerry A. Levad
Assignees (at issue)
Joy Manufacturing Company
Haden Schweitzer 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.