Issued Patents All Time
Showing 1–6 of 6 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6220305 | Coal tar enamel coated steel pipe and process for same | John R. Johnson, C. Sherill Henegar | 2001-04-24 |
| 5713393 | Coal tar enamel coated steel pipe and process for same | John R. Johnson, C. Sherill Henegar | 1998-02-03 |
| 5567480 | Coal tar enamel coated steel pipe and process for producing same | John R. Johnson, C. Sherill Henegar | 1996-10-22 |
| 5534134 | Low PAH pitch and process for same | Eric F. V. Scriven | 1996-07-09 |
| 5534137 | Process for de-ashing coal tar | E. Sean Griggs | 1996-07-09 |
| 5266184 | Process for increasing pitch yield from coal tar | — | 1993-11-30 |