Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4878944 | Method of treating metallic oxide impregnated dust | D. J. Rapp | 1989-11-07 |
| 4852818 | Material comminutor | David J. Nebel, John L. Shulan, William P. Liljestrom | 1989-08-01 |
| 4851110 | Air pump separator method and apparatus | David J. Nebel, John L. Shulan, William P. Liljestrom | 1989-07-25 |