PURPOSE: To increase the dust collection efficiency and to reduce the pressure loss, by providing the outlet duct rising at the center of cylinder and opening upward through the hopper tilt wall to induce the gas downward.

CONSTITUTION: The cyclon 1 consists of the cylinder 2, hopper 3, inlet duct 4, and outlet duct 5, and the outlet duct is provided through the hopper tilt wall opposite to the inlet side and connected to the carrier duct 8 providing the raw material inlet 7 via the curved duct 6. The cement raw material 10 goes upward on the flow of kiln exhaust gas and enters the cyclon via the inlet duct 4, reduced gradually at the extension of inlet duct and dropped with inertia and collected in the hopper. The raw material not fallen down is fallen down in the hopper with the spiral centrifugal force of gas at the cylinder, but since the outlet duct is coverted with the cover 2a at the upper opening, the discharge of raw material due to inducing can be prevented.