Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4942982 | Silo cleaning apparatus | Wesley D. Hartwigsen, Alan D. Johnson, Kenneth L. White | 1990-07-24 |
| 4764221 | Silo cleaning process | Wesley D. Hartwigsen, Alan D. Johnson, Kenneth L. White | 1988-08-16 |