Issued Patents All Time
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 8944114 | Mortar-coated steel pipes and methods of making the same | Richard I. Mueller, Ralph Friedrich | 2015-02-03 |
| 8627854 | Pressure cast concrete or mortar lined steel pipes and methods of making the same | Ralph Friedrich, Paul Kubat | 2014-01-14 |
| 8069880 | Pressure cast concrete or mortar lined steel pipes and methods of making the same | Ralph Friedrich, Paul Kubat | 2011-12-06 |
| 6363975 | Bonding of steel strips in steel strip laminate pipe | — | 2002-04-02 |
| 6273143 | Bonding of steel strips in steel strip laminate pipe | Ralph Friedrich, Garrett J. Endres, Lamont Thomas Inglehart, Stephan de Bie, Jeroen Van Brakel | 2001-08-14 |