Granted Patent
Utility
US 6,149,138 · App. 09/238,239
Portable humidifier with keyed replaceable cartridge element
Inventor:
Walter Birdsell
Patented Case
View Patent ↗
Granted: Nov 21, 2000
Filed: Jan 27, 1999
Inventor
Walter Birdsell
Assignee (at issue)
Honeywell 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.