| Number | Name | Date | Kind |
|---|---|---|---|
| 3458130 | Juhlin | Jul 1969 | |
| 3977467 | Northrup, Jr. | Aug 1976 | |
| 4409889 | Nutlrdon | Oct 1983 | |
| 4523588 | Dolsky | Jun 1985 | |
| 4531454 | Spoormaker | Jul 1985 | |
| 4534775 | Frazier | Aug 1985 | |
| 4955997 | Robertson, III | Sep 1990 | |
| 4993629 | Wylie | Feb 1991 | |
| 5097674 | Imaiida et al. | Mar 1992 | |
| 5225167 | Wetzel | Jul 1993 | |
| 5302354 | Watvedt et al. | Apr 1994 | |
| 5336128 | Birdsong | Aug 1994 | |
| 5348563 | Davis | Sep 1994 | |
| 5562286 | Brinket | Oct 1996 | |
| 5942323 | England | Aug 1999 | |
| 5961702 | Doneit | Oct 1999 |
| Entry |
|---|
| United Air Specialties, Inc., Advertisement Brochure entitled, “Crystal-Aire Modular Air Cleaning Systems”, © 1992, pp. 1-4. |