of the first stage may however vary according to the lightening degree desired for the centrifugal effect depending on whether quality or production is given precedence while the rotor of the second stage generally has radial blades the outlet 9 as illustrated in fig1 brings the juice into the second refinement stage where it is subjected to the forces of the further bladed rotor which forces it against a sieve 15 before sending it through an outlet pipe 13 to a further stage or to a collection tank of the finished juice also in this last case an outlet 14 is provided for the separate collection of the waste products from the second refinement stage this waste is obviously finer than that produced by the first stage as regards the arrangement of the blades 3b they are preferably radial and substantially rectangular in shape and are mounted on the central shaft 2 according to an alternative embodiment of the invention which is not illustrated the first produced finest juice can be sent on to the second stage while the denser juice can be used for other purposes concerning the regulation of the degree of pulping obtainable with the first stage of the machine of.