Abstract: The present invention pertains to a process and devices for producing beam-shaped moldings from fine plant parts mixed with binders in molding presses. Based on the discovery that the degree of compaction of the core of such moldings decreases with increasing cross section of the moldings, it is suggested in the present invention that the core zone of the molding be formed by an additional amount of fine parts moved there and compacted deliberately, which amount of material acts reactively as a compression zone to the moveable walls surrounding it during the compaction of the molding. Compaction of the molding over its entire cross section and at the same time particularly great compaction of the peripheral zones of the molding are thus achieved. The strength and the bending resistance of such moldings are particularly high, and such moldings are therefore also suitable for forming railroad ties.

Abstract: Extrusion of a mixture of vegetable bits with a binder, particularly wood chips with a weather-resistant binder, involves precompressing in a compression chamber of an extrusion press the mixture by a compression stroke transverse to the extrusion axis, the compression stroke being delivered by at least one precompression piston. Prior to the precompression elongated bits of the mixture are acted on by an orienting influence so that the elongated bits are deposited substantially parallel to the extrusion axis. The outer layers of the mixture are compressed with a reduced precompression ratio so that the bits oriented prior to precompression remain fixed in position during the subsequent extrusion stroke.

Abstract: An extruder has a nozzle from which it extrudes a strand formed of a mixture of wood chips and a synthetic-resin binder into a passage formed by a plurality of transversely and longitudinally movable walls. Opposite walls are urged transversely inwardly by respective hydraulic cylinders to compact and densify the strand as it cures, and other cylinders urge the walls upstream toward the nozzle with a force slightly smaller than the extrusion force. Thus as the extrusion force exceeds the opposite longitudinal biasing force the walls will move downstream with the strand, to return upstream between advance steps of the strand.