Abstract: A hollow body, a rotor, with holes in the bottom and the side wall, is immersed down into a liquid and rotated with the help of a shaft suspended over the liquid.The liquid, which enters the rotor through the hole in the bottom, will, on account of the centripetal force, acquire a surface in the shape of a paraboloid of revolution. The centripetal force will throw the liquid out through the holes in the side wall, while new liquid will continuously enter through the bottom of the rotor.The shaft for the rotor can be hollow, and through this gas, solid or liquid materials can be added to the liquid.The invention makes possible the treatment in various ways of different types of liquid, from aqueous suspensions to molten metal.