airwash separator 26 or other separation device which may include screens for separating out abrasive which has broken down to a point where it is too fine for further treatment the separating device 26 effects a separation of the reusable abrasive from the fines dust and other materials and recirculates the abrasive to the wheels 16 for further treatment referring to fig1 the means for causing the parts 20 suspended on the hangers 12 to rotate when in front of the blast area is illustrated each hanger 12 has mounted thereon a smooth gear or disk 28 which engages a motor driven endless belt conveyor 30 thus as each hanger 12 passes into the vicinity of the belt conveyor 30 the smooth gear 28 contacts the rotating endless belt 30 causing rotation of the hanger 12 and the part 20 suspended therefrom insuring an effective treatment of the total surface of the part 20 by the centrifugal blasting wheels 16 one of the essential features of the present invention is the ability of the device to carry out a continuous particulate treatment operation without the need for the usual batching operations wherein the operation must be interrupted to remove finished parts and insert a new supply of unfinished parts to be treated this continuous operation is achieved by use of a rotary vestibule which operates to keep the blast compartment 14 sealed while at the same time providing ingress and egress for each hanger 12 as it moves along the monorail 10 as will be appreciated the spacing between the hangers 12 is determined by the dimensions of the rotary vestibule and the number and spacing of sealing partitions included thereon in the fig1 embodiment the rotating vestibule 34 is illustrated as having five partitions 36.