> Self cleaning centrifuges are common in the industrial area I Googled self-cleaning centrifuge images and this is one example http://www.filtertech.com/model-acf-centrifuge.php There's a brief description of the method used. The material I'm looking at separating has only slightly less than neutral buoyancy, whereas the solids separation above might be easier if it is quite a different density to the oil (especially if the oil is heated to reduce viscosity) The principle seems a good one though. It could work with a slow feed rate to give the suspended particles time to settle. Which isn't a big deal, the UV treatment takes a few days to process all the water anyway, and it's ongoing =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D > I would recommend against Siemens controllers for your centrifuge My fish eat worms. And rice, bread, peas, chicken (poor old chickens. Everything eats chicken). To see them pull a slug apart is more [EW] than [EE] Tug-o-war with spaghetti is my favourite http://dl.dropbox.com/u/18683201/pasketti_241110-%20094.jpg http://dl.dropbox.com/u/18683201/pasketti_241110-%20071.jpg They made quick work of the tadpoles I put in. Big ones they were too, but down in one --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .