Cylindrical filter screen with tensioning mechanism
A filter assembly including a filter screen ( 27 ) comprising a band ( 27 ′) of porous material extending between two axially aligned opposing ends ( 38, 38 ′) and defining a cylindrical periphery ( 29 ), wherein the ends ( 38, 38 ′) are each secured to a dynamic tensioning mechanism ( 46 ) that permits the ends ( 38, 38 ′) to move bi-directionally relative to one another about the periphery ( 29 ) of the filter screen ( 27 ).
1. A filter assembly comprising a filter screen ( 27 ) comprising a band ( 27 ′) of porous material extending between two axially aligned opposing ends ( 38 , 38 ′) which overlap each other from 10 to 100 mm and define a cylindrical periphery ( 29 ),
wherein end ( 38 ) includes a radially inner surface ( 39 ) and end ( 38 ′) has a radially outer surface ( 39 ′) and wherein at least one of the inner surface ( 39 ) or outer surface ( 39 ′) includes a low friction coating or covering having a coefficient of friction less than 0.3 as measured by ASTM G115-10 (2013),
wherein the assembly is characterized by the ends ( 38 , 38 ′) being secured to a dynamic tensioning mechanism ( 46 ) that permits the ends ( 38 , 38 ′) to move bi-directionally relative to one another about the periphery ( 29 ) of the filter screen ( 27 ).
2. The filter assembly of claim 1 wherein the dynamic tension mechanism ( 46 ) comprises at least one spring ( 56 ) secured to each end ( 38 , 38 ′) of the band ( 27 ′).
3. The filter assembly of claim 2 further comprising a clasp ( 58 , 58 ′) extending radially inward from each end ( 38 , 38 ′) of the band ( 27 ′), and wherein the spring ( 56 ) is secured to the clasps ( 58 , 58 ′).
4. The filter assembly of claim 3 further comprising mounting plates ( 60 , 60 ′) secured to the ends ( 38 , 38 ′) of the band, and wherein the clasps ( 58 , 58 ′) extend radially inward from the mounting plates ( 60 , 60 ′).
5. The filter assembly of claim 1 further comprising a support frame ( 44 ) comprising a cylindrical grid of circular ribs ( 62 ) and axial supports ( 64 ) which define a cylindrical outer periphery ( 45 ), and wherein the filter screen ( 27 ) is mounted concentrically about the outer periphery ( 45 ) of the frame ( 44 ).
6. The filter assembly of claim 1 further comprising a hydroclone ( 10 ) comprising:
a tank ( 12 ) including a fluid inlet ( 14 ), a filtered fluid outlet ( 16 ), an effluent outlet ( 18 ) and an inner peripheral wall ( 22 ) enclosing at least one chamber ( 24 );
a filter sub-assembly ( 26 ) located within the chamber ( 24 ) and comprising a cylindrical filter screen ( 27 ) centered about an axis (X), wherein the filter screen ( 27 ) includes a plurality of pores ( 32 ) passing therethrough, and wherein the filter screen ( 27 ) encloses a filtrate chamber ( 36 ) in fluid communication with the filtered fluid outlet ( 16 ) such that fluid passing through the pores ( 32 ) enters the filtrate chamber ( 36 ) and may exit the tank ( 12 ) by way of the filtered fluid outlet ( 16 ); and
a cleaning assembly ( 48 ) comprising at least one cleaning member ( 52 ) biased against and adapted to rotate about the periphery ( 29 ) of the filter screen ( 27 ).