Plastic septic tank having layered composite wall
US8151999B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 2009 |
| Grant date | Apr 10, 2012 |
| Priority date | — |
| Expiry date | Mar 16, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F3/28
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A septic tank or storage tank has a corrugated thermoplastic wall which has a composite layered structure. A tank wall comprises an inner layer of solid plastic for containing liquid; an outer layer made of solid plastic, for resisting external mechanical forces, and a middle layer of closed cell foam plastic for both resisting liquid flow which penetrates the inner or outer layer and for heat retention which encourages biological processes. In an embodiment, the middle layer has less than about 55 percent of the density of the inner and outer layers, and the inner layer is substantially thinner than the outer layer. The three layers are integrally attached at the time of formation of the tank by rotational molding. The tank has good resistance to mechanical forces and provides insulation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.