Patent ID: 8231794
Filing Date: 2012-07-31
Classification: B01D,C02F

Abstract:
1. A method for operating a water filtering system that includes a feed input ( 62 ) that receives pressurized feed water from a pressured feed source ( 110 ) and that allows the pressured feed water to flow downstream through a passage ( 66 ) that holds a filter ( 72 ) to produce clean water, or filtrate ( 85 ) during filtrate production and that retains some of the filtrate in a storage region ( 82 ), and that, during a backflush, applies pressure to filtrate in said storage region to flow filtrate upstream through the filter, wherein said system includes walls forming a confined volume ( 94 ) and a moveable member ( 92 ) in said confined volume, said moveable member having a downstream face, and with an upstream face ( 132 ) of said moveable member exposed to the pressure of filtrate in said storage region, wherein: during a backflush operation, stopping the flow of said feed fluid to said feed input ( said step of applying feed fluid to said downstream face during a backflush operation includes applying said feed fluid to a downstream face of a rigid moveable member which has a downstream end periphery that is sealed to stationary walls of said confined volume around a first area and that has an upstream end periphery that is sealed to said stationary walls around a second area that is smaller than said first area, to thereby increase the backflush pressure applied to said filtrate in said storage region.