Pulsing portions of a filter cell to extend a filter run
US4976873A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 14, 1989 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Dec 14, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D24/4869
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An improved method for operating a down-flow granular medium filter is disclosed which increases the effective filtration time between backwashes. The filter tank cell is divided into a plurality of subcells, each individually adapted and controlled for periodic intermittent upwardly-directed pulses of fluid passed through the filter bed within each subcell from an array of orifices beneath or in the bed. During the filtration run, one subcell is pulsed to improve the porosity of that portion of the filter bed while the remainder of the subcells continue to filter wastewater. After initiation of the first pulsing cycle for a subcell, additional subcell pulsing cycles are initiated sequentially. At the end of the filtration run the whole filter cell is backwashed to remove particulate matter from the bed and prepare the bed for the next filtration run.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.