Abstract: A filter includes a rigid core through which the filtrate passes and about which there are wound a number of elongated porous tubular filter mediums that contain a resilient grid, there being a scrubber screen between successive turns of each filter medium, and resilient means yieldably enclosing the outermost surfaces of the helically wound parts. The filter mediums compress radially and expand radially in response to fluid pressure variations to produce relative movement between the filter mediums and the scrubber screen by which cleaning takes place, thereby extending filter life. The solids that have been filtered out are collected and built up on the screen and the helical assembly expands diametrically a corresponding amount.