Abstract: An improved hydrocyclone provided with a back wall with at least two ramps, where the ramps impart a greater axial velocity component to the fluids at the periphery as measured radially from the longitudinal axis of the hydrocyclone and a lesser axial velocity component to portions of the incoming fluid stream closer to the longitudinal axis of the hydrocyclone. The ramps of the back wall correspond generally to the swirl pattern within the hydrocyclone, a combination of axial and tangential velocity components, enabling the incoming fluid stream to reach the desired flow pattern more quickly and efficiently than otherwise possible.