Cross Flow Filter Device With Concentric Filter Elements

Abstract

Cross flow filter device comprising a longitudinal first filter element ( 1 ) having a first width (w 1 ) and a longitudinal central axis ( 8 ), a longitudinal second filter element ( 2 ) having a second width (w 2 ) and being longitudinally installed substantially concentrically inside said first filter element ( 1 ), a housing ( 3 ) surrounding said first filter element (1), said cross flow filter device having respectively a raw material inlet ( 4 ), a concentrate outlet ( 5 ), and a first filtrate outlet ( 6 ) connected to said first filter element ( 1 ). The ratio between the second width (w 2 ) and the first width (w 1 ) is 65%, preferably at least 70% and more preferably about 75%.

1 . Cross flow filter device provided for filtering a raw material comprising particles in a medium, said cross flow filter device comprising: 
 a longitudinal first filter element ( 1 ) having a first width (w 1 ) and a longitudinal central axis ( 8 ),    a longitudinal second filter element ( 2 ) having a second width (w 2 ), smaller than said first width, and being longitudinally installed substantially concentrically inside said first filter element ( 1 ), and    a housing ( 3 ) surrounding said first filter element ( 1 ), said cross flow filter device having respectively a raw material inlet ( 4 ), a concentrate outlet ( 5 ) provided to exit a concentrate being said raw material substantially enriched in particles, and a first filtrate outlet ( 6 ) provided to exit a filtrate being said medium substantially depleted in particles, said filtrate outlet being connected to said first filter element ( 1 ), wherein the ratio between the second width (w 2 ) and the first width (w 1 ) is at least 65%.    
     
     
         2 . Cross flow filter device according to  claim 1 , wherein said ratio between the second width (w 2 ) and the first width (w 1 ) is at least 70%.  
     
     
         3 . Cross flow filter device according to  claim 1 , wherein said ratio between the second width (w 2 ) and the first width (w 1 ) is about 75%.  
     
     
         4 . Cross flow filter device according to  claim 1 , wherein said ratio between the second width (w 2 ) and the first width (w 1 ) is at most 95%.  
     
     
         5 . Cross flow filter device according to  claim 1  wherein the first filter element ( 1 ) and the second filter element ( 2 ) are two separate filter elements ( 1 , 2 ) having each their own filtrate outlet ( 6 , 7 ) being different from each other, the filtrate outlet ( 6 ) of the first filter element ( 1 ) being said first filtrate outlet ( 6 ) and the filtrate outlet ( 7 ) of the second filter element ( 2 ) being a second filtrate outlet ( 7 ).  
     
     
         6 . Cross flow filter device according to  claim 1 , wherein the raw material inlet ( 4 ) and the concentrate outlet ( 5 ) are substantially aligned with said longitudinal central axis ( 8 ).  
     
     
         7 . Cross flow filter device according to  claim 1 , wherein the first ( 6 ) and the second filtrate outlets ( 7 ) are respectively prolonged by a first ( 9 ) and a second nozzle ( 10 ) which are ended respectively by a first ( 11 ) and a second valves ( 12 ), each valve ( 11 , 12 ) having at least an open position and a closed position and being separately controlled.  
     
     
         8 . Cross flow filter device according to  claim 1 , wherein each filter element ( 1 , 2 ) comprises a filter media, each filter media of each filter element ( 1 , 2 ) having its own cut-off, said cut-off of the filter media of the first filter element ( 1 ) being substantially different from said cut-off of the filter media of the second filter element ( 2 ).  
     
     
         9 . Cross flow filter device according to  claim 1 , wherein each filter element ( 1 , 2 ) comprises a filter media, each filter media of each filter element ( 1 , 2 ) having its own cut-off, said cut-off of the filter media of the first filter element ( 1 ) being substantially similar to said cut-off of the filter media of the second filter element ( 2 ).  
     
     
         10 . Cross flow filter device according to  claim 9 , wherein each filter media is manufactured from a material selected from the group consisting from metallic material, organic material or inorganic material.  
     
     
         11 . Cross flow filter device according to  claim 10 , including a circulation pump ( 13 ) between the concentrate outlet ( 5 ) and the raw material inlet ( 4 ).  
     
     
         12 . Cross flow filter device according to  claim 11 , wherein a back-flush device is provided comprising: 
 an expansion vessel ( 17 ), having a first port ( 14 ) and a second port, identical or different from said first port ( 14 ),    a third nozzle ( 15 ) connected to said first port ( 14 ) of the expansion vessel ( 17 ) and to said first nozzle ( 9 ) between the first filtrate outlet ( 6 ) and the first valve ( 11 ), and    a fourth nozzle ( 16 ) connected to said second port of the expansion vessel ( 17 ) and to said second nozzle ( 10 ) between the second filtrate outlet ( 7 ) and the second valve ( 12 ).    
     
     
         13 . Cross flow filter device according to  claim 12 , in which said third nozzle ( 15 ) comprises a third valve ( 24 ) and said fourth nozzle ( 16 ) comprises a fourth valve ( 25 ), said third ( 24 ) and said fourth valves ( 25 ) having each at least an open position and a closed position and being separately controlled.  
     
     
         14 . Cross flow filter device according to  claim 13 , wherein the concentrate outlet ( 5 ) is ended by a throttle valve ( 23 ).