Granted Patent
Utility
US 4,574,973 · App. 06/731,473
Door system for precipitators and the like
Inventors:
Robert L. Lewis, J. Albert Hudson
Patented Case
View Patent ↗
Granted: Mar 11, 1986
Filed: May 7, 1985
Inventors
Robert L. Lewis
J. Albert Hudson
Assignee (at issue)
Environmental Products & Services Limited
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.