A separator device for removing particles from suspension in a liquid comprises: a housing (12), having first (19) and second (40) chambers with apertures (98) for ingress and egress of liquid into the first chamber (19); means (100) for setting up a swirl of liquid within the first chamber (19); apertures enabling flow of liquid between the first chamber (19) and the second chamber (40); means for setting up a swirl of liquid within the second chamber (40), the swirl in the second chamber (40) being in substantially the opposite direction to the swirl in the first chamber, and there being no substantial flow in the second chamber (40) which is in the same direction as the swirl in the first chamber (19).