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:
Jan. 08, 1991
Filed:
Dec. 18, 1989
Applicant:
Inventor:
Ronald L Edwards, Wausau, WI (US);
Assignee:
Zimpro/Passavant Inc., Rothschild, WI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B01D / ;
U.S. Cl.
CPC ...
210794 ; 210108 ;
Abstract
An improved method for maintaining a granular medium filter in a clean, operable condition is disclosed. The time interval required for the level of liquid above the filter bed to drain from a backwash outlet level to the upper bed surface level following a backwash cycle is monitored. Upon this measured draindown time exceeding a predetermined interval of time, a chemical cleaning cycle is initiated for the granular medium bed filter.