Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4877395 | System control means to preheat waste oil for combustion | Frank Schubach | 1989-10-31 |
| 4797089 | System control means to preheat waste oil for combustion | Frank Schubach | 1989-01-10 |