Patent ID: 8318021

Claim:
A process for back flushing a tubular capillary ultrafiltration membrane water filtration system having at least two filters, whereby a first filter is utilized to power wash at least a second filter comprising: providing a water filtration system having at least a first filter and a second filter connected in parallel to each other, each said first and second filter having a first end and a second end, wherein the first ends of each said filter are provided with valving elements for selectively communicating with a water supply line, and the second ends of each said filter are provided with valving elements for selectively communicating with a drain line, each of said filters having a clean water outlet port provided with valving elements for selectively communicating with a clean water outlet line; providing a normal operating mode wherein water from the supply line flows through each said first and second filters and out to the clean water outlet; providing a filter selectable back flush mode for either said first or said second filter when one of said filters is in need of cleaning, wherein for said filter in need of cleaning, said water supply line valving element and said clean water outlet port valving element are closed and said filter in need of cleaning drain line valving element is opened, whereby water will continue to flow from said water supply line into said other filter and out said other filter clean water outlet port; wherein water from said other filter clean water outlet port would then flow backward into said filter in need of cleaning clean water outlet port and through said filter in need of cleaning; whereby filtered material would be pushed away from inside of the capillary membranes of said filter in need of cleaning and out said drain valving element thereof to said drain line; operating in said back flush mode for a requisite time period sufficient to have a cleaning effect on said first filter; and returning said valving elements to their normal operating positions; the back flush mode being conducted such that clean water flows from said other filter through said clean water outlet port, while water flows from said other filter through said first filter for back flushing during a period of time when said outlet port valving element is open.