Abstract: A low velocity, low temperature, inertial particle separator is disclosed which imposes minimum resistance to the flow of gas through the apparatus. The separator includes a slowly revolving drum with radiating cups around which the gas must flow. Change of direction of the flowing gas as it flows around the cups causes the entrained particles to be collected by the cup-shape of the cups. A vacuum system is provided for inducing the collected particles to migrate to a central axially disposed collection system which draws the particles away by suction.