A means for dialysis comprises a flow of unfiltered fluid or blood 1, said fluid undergoing at least one stage of partial filtration by means of a self-cleaning filter 2, said partially filtered fluid passing through a second filter 3, said second filtered fluid returning to said partially filtered flow. The said partially filtered flow may undergo a second stage of partial filtration 4. At a final stage said second filtered flow enters a storage chamber 5 having means for emptying said chamber and flushing said second filters with said final second filtered flow fluid. A turbine 6 driven by the flow of a patients blood drives a generator 7, which powers a pump 8 for flushing the filters. The self-cleaning filters may be angled to allow particles to be washed past the filter. The means may be wholly contained within a patient.
