The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 11, 1990
Filed:
Dec. 14, 1989
David S Ross, Lorain, OH (US);
Zimpro/Passavant Inc., Rothschild, WI (US);
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.