New and improved apparatus and method for thorough, non-invasive mixing of a flowing fluid stream, either continuous or segmented, are provided and, as disclosed, are embodied in a mixing conduit which comprises a plurality of interconnected bends, which may be in the form of arcuate coils or sections, successive arcuate sections being operable to establish secondary flow patterns in differing orientations within the flowing fluid stream, or individual segments thereof. Such arcuate sections may be disposed in a same plane, if formed in serpentine fashion, or in non-parallel, preferably orthogonal planes, if formed in a tortuous fashion. Also, the arcuate sections, or a series thereof may be formed in stacked fashion and located in essentially parallel planes.

A particulate material transfer device comprises a tubular body having a passage with an entrance to receive particulate material and an exit for discharging material and an annular chamber about the body in which a travelling member is disposed for movement about the body in a manner to impart vibrations thereto. A fluid inlet supplies pressurized air to the chamber to cause the travelling member to move about the body to impart vibrations thereto. A plurality of fluid discharge openings extend from the chamber to the passage to discharge pressurized fluid toward the exit to transfer material from the entrance through the passage toward the exit.