Appeal 2007-1768
Application 10/377,647
BRIEF STATEMENT OF THE INVENTION
Appellants’ invention is directed to a method for cleaning one or more
filtering membranes. The claimed method includes flowing a chemical
cleaner in pulses through the membranes while the tank water is being
drained or is below the level of the membranes. Representative independent
claim 16, as presented in the Brief, appears below:
16 A method for cleaning one or more filtering membranes normally
immersed in tank water containing solids in a tank and used to
produce a permeate in one or more cleaning events, each cleaning
event comprising the steps of:
(a) stopping permeation;
(b) draining the tank water from the tank to below the level of
the membranes:
and,
(c) while the tank water is being drained or is below the level of
the membranes, flowing a chemical cleaner in pulses through the
membranes in a direction opposite to the direction in which water lean
in solids normally permeates through the membranes;
and,
(d) refilling the tank,
wherein,
(e) the cleaning events are performed at least once a week; and.
(f) the product of the concentration of the chemical cleaner
expressed as an equivalent concentration of NaOCl in cleaning
efficacy and the duration of all cleaning events in a week is between
2,000 minutes*mg/L and 20,000 minutes*mg/L.
2
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