Abstract: A cyclonic separating apparatus for separating solid material from a fluid includes a separating chamber, an inlet communicating with the separating chamber for carrying the fluid with the solid matter entrained therein to the separating chamber, and an outlet for carrying the fluid away from the separating chamber after the solid material has been separated therefrom. The outlet is formed by a conduit communicating with the interior of the separating chamber and having a longitudinal axis. A plurality of grooves are formed in an interior surface of the conduit outlet and extend in the same direction as the longitudinal axis. The presence of the grooves in the outlet has the effect of reducing noise generated by the apparatus when in use and also improves pressure recovery.