| Number | Name | Date | Kind |
|---|---|---|---|
| 3570018 | Sargent et al. | Mar 1971 | A |
| 3582995 | Enenstein | Jun 1971 | A |
| 3597768 | Wofford | Aug 1971 | A |
| 4377875 | Brubakken | Mar 1983 | A |
| 4653128 | Canalizo | Mar 1987 | A |
| 4704747 | Brubakken et al. | Nov 1987 | A |
| 4947491 | Parkinson et al. | Aug 1990 | A |
| 5038418 | Frey | Aug 1991 | A |
| 5983411 | Demoret | Nov 1999 | A |
| 6038710 | Baron | Mar 2000 | A |
| 6129117 | Eriksson | Oct 2000 | A |
| Entry |
|---|
| www.plumbing.com/sewagesystems.html, accessed May 16, 2001, showing Liberty Pumps'“LowPro Sewage System” and Zoeller's Qwik Jon, accessed May 16, 2001. |