Device comprising a compartment for separating the solids and liquids, saidcompartment comprising abase that is concavely curved according to a cylindrical portion having atransverse axis and is formed ofa sieve； an idler roller mounted transversely on an arm； driving means whichactuate said arm, andresilient means for adjusting the pressure exerted by the rollers； whereinboth the contact interfacebetween the sieve and the roller and the rotational interface between theroller and the arm are made of anon-metal material on at least one of the two contacting surfaces that formeach of said interfaces, suchthat, at said interfaces, there is no metal-on-metal contact between surfacesmoving relative to oneanother.
