Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5861057 | Drainage concrete | Siegfried RIFFEL | 1999-01-19 |
| 5691050 | Concrete molding with improved acid resistance | Helmut Rinno | 1997-11-25 |
| 5599597 | Concrete molding with improved acid resistance | Helmut Rinno | 1997-02-04 |
| 5047295 | Concrete roof tile | Bernhard Dotzauer, Rolf Dersch, Johannes Vinke, Harutyun Hanciogullari, Manfred Schwartz | 1991-09-10 |