| Number | Name | Date | Kind |
|---|---|---|---|
| 3733790 | Pierce | May 1973 | |
| 3788046 | Kaeppler et al. | Jan 1974 | |
| 3873286 | Wurtenberg | Mar 1975 | |
| 4704144 | LeBlanc et al. | Nov 1987 | |
| 5277704 | Miller et al. | Jan 1994 |
| Number | Date | Country |
|---|---|---|
| 6-226024 | Aug 1994 | JPX |
| Entry |
|---|
| Torit Installation and Operation Manual, Series 50, 60, 70, snf 80; Models 54, 64, 66, 75, 81 and 84, Donaldson Company, Inc. (1990). |