Cross-flow filtration system including particulate settling zone
Cross-flow filtration systems and corresponding methods for separation particulate matter from liquids. A representative system includes a cross-flow filtration zone ( 24 ) in fluid communication with a particulate settling zone ( 30 ) and further includes a fluid inlet ( 14 ) in fluid communication with one of the zones and a process fluid outlet ( 20 ) and in fluid communication with the other zone. A fluid treatment pathway ( 28 ) extends from the fluid inlet ( 14 ), through the cross-flow filtration and particulate settling zones ( 24, 30 ) to the process fluid outlet ( 20 ). A filter assembly ( 26 ) is located within the cross-flow filtration zone ( 24 ) and comprises a membrane surface ( 44 ) that isolates a filtrate chamber ( 46 ) from the fluid treatment pathway ( 28 ), and the filtrate chamber ( 46 ) is in fluid communication with a filtered fluid outlet ( 16 ). A recirculation pump (Z) in fluid communication with the process fluid outlet ( 20 ) and fluid inlet ( 14 ). A pressurizable recirculation loop (A) comprises the fluid treatment pathway ( 28 ) and recirculation pump (Z) and the recirculation pump (Z) is adapted for driving pressurized through the recirculation loop (A). A feed pump (Y) is adapted to introduce feed liquid into the system ( 10 ); and an effluent outlet ( 18 ) in fluid communication with the particulate settling zone ( 30 ). The feed pump (Y), effluent outlet ( 18 ) and filtered fluid outlet ( 16 ) reside outside of the recirculation loop (A).
1. A cross-flow filtration system ( 10 ) comprising:
a tank ( 12 ) including an inner peripheral wall ( 22 ) surrounding a cross-flow filtration zone ( 24 ) and particulate settling zone ( 30 ) sequentially aligned along an axis (X), wherein the cross-flow filtration zone ( 24 ) is in fluid communication with a the particulate settling zone ( 30 );
a fluid inlet ( 14 ) in fluid communication with one of said zones and a process fluid outlet ( 20 ) and in fluid communication with the other zone;
a fluid treatment pathway ( 28 ) extending from the fluid inlet ( 14 ), through the cross-flow filtration and particulate settling zones ( 24 , 30 ) and to the process fluid outlet ( 20 );
a filter assembly ( 26 ) located within the cross-flow filtration zone ( 24 ) and comprising a membrane surface ( 44 ) that isolates a filtrate chamber ( 46 ) from the fluid treatment pathway ( 28 ), wherein the filtrate chamber ( 46 ) is in fluid communication with a filtered fluid outlet ( 16 );
a cleaning assembly ( 50 ) concentrically located about and rotatably engaged with the membrane surface ( 44 );
a recirculation pump (Z) in fluid communication with the process fluid outlet ( 20 ) and fluid inlet ( 14 );
a pressurizable recirculation loop (A) comprising the fluid treatment pathway ( 28 ) and the recirculation pump (Z), wherein the recirculation pump (Z) is adapted for driving pressurized fluid from the process fluid outlet ( 20 ) through the recirculation loop (A);
a feed pump (Y) adapted to introduce feed liquid into the system ( 10 ); and
an effluent outlet ( 18 ) in fluid communication with the particulate settling zone ( 30 );
wherein the feed pump (Y), effluent outlet ( 18 ) and filtered fluid outlet ( 16 ) reside outside of the recirculation loop (A).
2. The system ( 10 ) of claim 1 wherein the recirculation pump (Z) is adapted to drive at least twice the volume of liquid through the recirculation loop (A) as introduced by the feed pump (Y) and wherein the feed pump (Y) is adapted to provide a greater pressure increase than provided by the recirculation pump (Z).
3. The system ( 10 ) of claim 1 further comprising a valve ( 37 ) movable between a closed position that restricts flow of effluent from the particulate settling zone ( 30 ) and an open position that permits effluent to exit the system ( 10 ) by way of the effluent outlet ( 18 ) particulate settling zone ( 30 ).
4. The system ( 10 ) of claim 1 wherein cross-flow filtration zone ( 24 ) and particulate settling zone ( 30 ) are serially arranged along the fluid treatment pathway ( 28 ) with the particulate settling zone ( 30 ) being located downstream from the cross-flow filtration zone ( 24 ).
5. The system ( 10 ) of claim 4 wherein:
the membrane surface ( 44 ) is symmetrically located about the axis (X); and
the fluid treatment pathway ( 28 ) extends from the fluid inlet ( 14 ) and between the inner peripheral wall ( 22 ) of the cross-flow filtration zone ( 24 ) and the membrane surface ( 44 ) and further extends into the particulate settling zone ( 30 ) to exit the tank ( 12 ) through the process fluid outlet ( 20 ); and
an effluent pathway ( 29 ) extends from the particulate settling zone ( 30 ) and exits the tank ( 12 ) through the effluent outlet ( 18 ).
6. The system ( 10 ) of claim 5 wherein the fluid treatment pathway ( 28 ) includes a vortex region ( 25 ) located between the inner peripheral wall ( 22 ) of the tank ( 12 ) and the membrane surface ( 44 ) that is adapted for receiving incoming liquid and generating a vortex fluid flow about the filter assembly ( 26 ).
7. The system ( 10 ) of claim 6 further comprising a flow barrier ( 34 ) located between the cross-flow filtration and particulate settling zones ( 24 , 30 ) and defining a respective cross-flow filtration chamber ( 24 ) and particulate settling chamber ( 30 ).
8. The system ( 10 ) of claim 7 wherein the flow barrier ( 34 ) directs a majority of fluid flow between the cross-flow filtration chamber ( 24 ) and particulate settling chamber ( 30 ) to locations adjacent to the inner peripheral wall ( 22 ) of the tank ( 12 ).
9. The system ( 10 ) of claim 7 wherein the flow barrier ( 34 ) disrupts vortex fluid flow from the cross-flow filtration chamber ( 24 ) and the particulate settling chamber ( 30 ).
10. The system ( 10 ) of claim 5 further comprising comprises a conduit ( 31 ) including a process fluid inlet ( 33 ) located near the axis (X) of the particulate settling chamber ( 30 ) that is fluid communication with the process fluid outlet ( 18 ).