An innovative hydrocyclone was designed, in which a conical filtering wall replaces the conical section, producing another liquid stream leaving the equipment, besides underflow and overflow streams. The influence of the inlet diameter of a filtering hydrocyclone was analyzed by an experimental and computational fluid dynamics study. Data from conventional hydrocyclones of the same configurations were also obtained. Under identical operating conditions and geometry, the filtering hydrocyclone presented a better performance than the conventional device. Under the experimental conditions evaluated, an about twofold increase in inlet diameter reduces the Euler number significantly.