Abstract: Coaxial, dual agitator top-entering mixer has coaxial vertical drive shafts penetrating the center of the head of the vessel, driving a lower-speed outer scraper agitator and a higher-speed inner agitator. An inner rotary seal closes the upper end of an annular space between the inner and outer shafts. An outer rotary seal closes the opening around the outer drive shaft in the head of the vessel. A central bore along the inner drive shaft axis extends from its upper end down to a position just below the inner seal, with one or more cross-bored radial passages to the annular space between the drive shafts. A rotary fitting at the upper end of the inner drive shaft permits the introduction of a cleaning fluid into the central bore. The cleaning fluid passes through the bore and the radial passage into the annular space to clean accumulations from within the annular space. The cleaning fluid exits the annular space into the interior of vessel.

Abstract: A mixer of the present invention includes an outer cylinder into which powder material is loaded, a rotational axis which is located coaxially with the outer cylinder and discharges liquid material while forming the liquid material to fine particles, and a fin which has a rectangular shape and is disposed along an inner wall of the outer cylinder. The fin is independently revolvable around the rotational axis. The fin has side faces in a direction of revolution of the fin, each of which forms an inclined face such that a width of the fin becomes wider from an inner surface to an outer surface of the fin.