Issued Patents 1989
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4867229 | Method and means for applying a heat exchanger in a drill hole for the purpose of heat recovery or storage | — | 1989-09-19 |
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4867229 | Method and means for applying a heat exchanger in a drill hole for the purpose of heat recovery or storage | — | 1989-09-19 |