Apparatus for forming synthetic logs

Abstract

A log forming apparatus includes a slotted die chamber, a rotary feed auger for advancing loose particles into the die chamber, and a replaceable tip having a pressure face for engaging successive layers of particles from the auger and pressing these layers together into the shape of a log. The pressure face comprises a plurality of semi-circular grooves for forming ridges in each layer of particles which are pressed within corresponding grooves of a preceding layer during compaction. A mandrel extends axially forwardly of the pressure face and forms an axial bore through the log to facilitate the removal of heat and steam therefrom. The mandrel is hollow to direct a flow of compressed air through the bore to further facilitate such removal. The auger comprises an interrupted helical screw thread for providing a sensitive advancement of loose particles forwardly along a helical feed channel defined by the screw thread. The feed channel includes a forward discharge scoop of substantially constant volume. A clamp enables the slotted die chamber to be compressed to increase the backpressure applied to the log. A cooling/drying section comprises pressurized walls forming a log-conducting trough. An adjustment mechanism enables the pressure between the walls to be varied so as to alter the magnitude of the lateral forces which are applied to the log.