Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5168861 | Direct contact water heater | William C. Lutzen | 1992-12-08 |
| 4753220 | Direct contact water heater | William C. Lutzen, Michael W. Valentino | 1988-06-28 |
| 4574775 | Direct contact water heater | William C. Lutzen, Karen L. Gadomski | 1986-03-11 |