Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4871495 | Process for producing porous ceramic filter for filtering of particulates from diesel exhaust gases | Richard L. Helferich | 1989-10-03 |
| 4846906 | Methods for the manufacture of porous ceramic shapes containing membraneous surfaces | Richard L. Helferich | 1989-07-11 |
| 4812424 | Kiln furniture for the firing of ceramic articles | Richard L. Helferich | 1989-03-14 |