Polystyrene beads for drainage fields
US6467996B1 · kind B1 · utility
5Cited by
31References
16Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 8, 1999 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Apr 8, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A loose fill lightweight plastic aggregate for a preassembled drainage line unit. The bead comprises a central portion, at least three legs extending from each of the top and bottom of said central portion, a plurality of channels each defined by adjacent ones of said legs, the width of said legs being greater than the width of said channels. A rib protrides laterally from each of the sides of the central portion. In the drainage unit, the beads maintain a substantial void space for flow of waste water and also provide maximum surface area for bacterial breakdown of sewage wastes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.