Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4840145 | Process and a device for cleaning inner or outer walls of vertically extending or inverted tubes of heat exchangers | Frohmut Vollhardt | 1989-06-20 |
| 4831969 | Process and a device for cleaning inner or outer walls of vertically extending or inverted tubes of heat exchangers | Frohmut Vollhardt | 1989-05-23 |