Apparatus for conveying particulate material

Abstract

Apparatus for conveying particulate material of the type wherein it is desired that the material be simultaneously pre-compacted from a generally loose state to a more or less solid 'plug' state. A screw conveyor is arranged to deliver loose particulate material to an intermediate chamber at the end of the screw conveyor means wherein the material is pre-compacted by the action of the screw conveyor. Following the intermediate chamber, a piston reciprocating coaxially with the screw conveyor further urges the material in a direction coaxial with the centerline of the screw conveyor to further advance the material through a straight coaxial conduit within which the material becomes compacted to an increased degree of compactness, solely by the action of the reciprocating piston. The reciprocating piston has preferably an annular face, whose outside diameter is generally the same as that of the I.D. (inside diameter) of the conduit. The second, high degree of compactness is thus achieved solely by the action of the piston. Accordingly, the mounting of the screw conveyor is not subjected to extreme forces. The device is capable of compacting, for instance, fibrous material of a relatively low fibre shear strength to an extremely high compactness without exceeding the fibre shear limit in the area of the screw conveyor. Frictional drag in the conduit following the apparatus may be increased by vanes protruding inside of the conveyor. The depth of the friction increasing vanes may be selectively adjustable.