Granted Patent
Utility
US 5,924,821 · App. 08/864,600
Apparatus and method for gas and/or liquid exchange between an area outside and an area inside a bulk material pile
Inventors:
David L. Hansen, Donald V. Mazzarello
Patented Case
View Patent ↗
Granted: Jul 20, 1999
Filed: May 28, 1997
Inventors
David L. Hansen
Donald V. Mazzarello
Assignee (at issue)
Landfill Technologies, Inc.
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.