Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4855572 | Heater for use as either primary or auxiliary heat source and improved circuitry for controlling the heater | Linus E. Wallgren, Bobby L. Mason, William J. Siegel, Ole V. Olesen | 1989-08-08 |
| 4847471 | Heater for use as either primary or auxiliary heat source and improved circuitry for controlling the heater | Linus E. Wallgren, Bobby L. Mason, William J. Siegel, Ole V. Olesen | 1989-07-11 |