Filter element

Abstract

The invention concerns a filter element for fluids, in particular for hydraulic fluid, consisting of at least one foldable filter casing ( 10 ) with at least one filter layer ( 18, 20, 22, 24 ), which extends between two end caps ( 26, 32 ), characterized in that, in order to vary in regions the thickness of the filter casing ( 10 ), the height (h 1 ) of each filter fold ( 12, 44 ) increases from one end cap ( 26 ) to the other end cap ( 32 ) or, with the filter fold height (h 1 ) being maintained, the outer diameter ( 40 ) of the filter casing ( 10 ) varies in the direction of one of the end caps ( 26, 32 ).

1 . A filter element for fluids, in particular for hydraulic fluid, consisting of at least one foldable filter liner ( 10 ) having at least one filter layer ( 18 ,  20 ,  22 ,  24 ), which extends between two end caps ( 26 ,  32 ), characterized in that, in order to achieve a zonal variation of the thickness of the filter liner ( 10 ), the height (h 1 ) of each filter pleat ( 12 ,  44 ) increases from one end cap ( 26 ) to the other end cap ( 32 ), or that the outer diameter ( 40 ) of the filter liner ( 10 ) changes in the direction of one of the end caps ( 26 ,  32 ) whilst maintaining the filter pleat height (h 1 ). 
     
     
         2 . The filter element according to  claim 1 , characterized in that the filter liner ( 10 ) surrounds a hollow space ( 36 ), that the one end cap ( 26 ) is provided with a passage ( 30 ) for the supply of unfiltrate, which flows in filtration direction from the hollow space ( 36 ) towards the outside through the filter liner ( 10 ), and that the other end cap ( 32 ) is closed to said flow. 
     
     
         3 . The filter element according to  claim 1 , characterized in that the height (h 1 ) of the filter pleats ( 12 ,  44 ) changes in that it increases in the direction of the closed end cap ( 32 ). 
     
     
         4 . The filter element according to  claim 1 , characterized in that the change in the height (h 1 ) of the filter pleats ( 12 ,  44 ) is constant. 
     
     
         5 . The filter element according to  claim 1 , characterized in that the increase in pleat heights (h 1 ) causes a zonal increase in the outer diameter ( 4 ) of the filter liner ( 10 ). 
     
     
         6 . The filter element according to  claim 1 , characterized in that the increase in pleat heights (h 1 ) causes not only a zonal increase of the outer diameter ( 40 ) of the filter liner ( 10 ) but also a zonal decrease of the inner diameter ( 38 ) of the hollow space ( 36 ) of the filter liner ( 10 ). 
     
     
         7 . The filter element according to  claim 1 , characterized in that the outer diameter ( 40 ) of the filter liner ( 10 ) increases from the open end cap ( 26 ) towards the closed end cap ( 32 ). 
     
     
         8 . The filter element according to  claim 1 , characterized in that, in addition to pleats ( 12 ,  44 ) of a first kind, which determine the majority of the thickness of the filter liner ( 10 ) through their pleat height (h 1 ), preferably alternating pleats ( 42 ) of a second kind, which have a smaller pleat height (h 2 ) compared to the pleats of the first kind ( 12 ,  44 ), are provided. 
     
     
         9 . The filter element according to  claim 1 , characterized in that the zonal variation of the thickness of the filter liner ( 10 ) is achieved through local application of additional, in particular strip-like, filter layers ( 48 ,  50 ,  52 ,  54 ,  56 ).