Granted Patent
Utility
US 4,664,839 · App. 06/721,287
Use of crystalline layered sodium silicates for softening water and a process for softening water
Inventor:
Hans-Peter Rieck
Patented Case
View Patent ↗
Granted: May 12, 1987
Filed: Apr 9, 1985
Inventor
Hans-Peter Rieck
Assignee (at issue)
Hoechst GmbH
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.