Patent ID: 6776172
Filing Date: 2004-08-17
Classification: B01D,B08B,C02F,Y10S

Abstract:
A cleaning method for removing fine particles remaining adhered to at least part of an ultrapure water supply system due to electrostatic attractive force, the ultrapure water supply system having an ultrapure water production apparatus connected to a point of use of ultrapure water via a passage, comprising the steps of:(a) changing surface potential of fine particles remaining adhered to the at least part of the ultrapure water supply system into the same polarity as that of component parts constituting elements of the ultrapure water supply system by changing the surface potential of the fine particles from positive to negative, thereby eliminating the the electrostatic attractive force between the fine particles and the at least, least part of the ultrapure water supply system or producing repulsive electrostatic force between them; and (b) discharging the negatively charged fine particles, which are removed from the at least part of the ultrapure water supply system by elimination of the electrostatic attractive force or production of the repulsive electrostatic force, to the outside of the ultrapure water supply system, together with cleaning liquid or ultrapure water for rinsing, wherein the cleaning liquid or ultrapure water for rinsing containing the negatively charged fine particles bypasses an element of the ultrapure water supply system, the element serving to remove the negatively charged fine particles in the ultrapure water supply system.