Patent ID: 7217363

Claim:
A filter system for cleaning a fluid by passing it through a filter medium, said system being capable of cleaning said medium by backwashing and said system being capable, during the backwashing cycle, of preventing bacterial buildup, said system comprising: a) a tank having a closed shell with a curved bottom b) a filter medium resting inside and on the bottom of said tank, said medium filling at least a portion of said tank c) a tank input port passing through the shell of said tank to provide an inlet for the tank which accepts fluid used to backwash the medium in said system d) a tank output port passing through the shell of said tank to provide an outlet for the fluid in said tank after it has backwashed the medium in the tank by passing fluid through said medium e) a first array formed of at least one conduit for carrying fluid, said array having a first array input port which is connected to the tank input port inside the tank to accept the fluid from the tank input port, said first array having a plurality of first array output ports distributed along the length of its conduit to permit fluid supplied to said first array from said tank input port to be discharge from said first array into said medium, said first array being positioned generally above said curved tank bottom, and inside said medium to cause the fluid passing through said first array to further pass through said medium to clean said medium by way of backwashing said medium about and above said first array, said fluid being collected from said medium after backwashing for discharge from said tank and from said system through said tank output port, and f) a second array formed of at least one conduit for carrying fluid positioned in said medium below said first array and in the curved bottom area of said tank within said medium in said tank, said second array having a second array input port at one end of said second array conduit and a plurality of a second array output ports distributed along said second array conduit, said second array input port being connected to said first array to receive fluid from said first array and pass this fluid on through said second array output ports into said medium in the lower curved portion of the tank to dislodge and remove bacteria and debris in the medium thereby preventing bacterial buildup in this area, said second array consists of straight conduits positioned generally horizontally in said tank and each conduit extending a length which avoids contact with said curved portion of said tank, and wherein the second array conduits contain end caps and said end caps contain at least one second array output port to extend the cleaning range in the direction beyond said end caps.