Issued Patents All Time
Showing 1–9 of 9 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7718581 | Method using composition to reduce cutting head wear | Herbert Egli | 2010-05-18 |
| 7709422 | Method and composition for injection at a tunnel boring machine | — | 2010-05-04 |
| 7686542 | Method of protecting a surface of rock or soil | — | 2010-03-30 |
| 6802673 | Tunnel boring with foamed composition | — | 2004-10-12 |
| 6485233 | Foaming composition | — | 2002-11-26 |
| 5925699 | Concrete curing admixtures | Bernhard Leikauf, Qiwei Yang | 1999-07-20 |
| 5322562 | Production of cement-mortar dry mix | Heinz W. Schmitt, Salvatore Valenti, Qiwei Yang | 1994-06-21 |
| 5252636 | Dry mixture for epoxy cement concrete | Qiwei Yang | 1993-10-12 |
| 5118197 | Process for mixing two liquids | — | 1992-06-02 |