Preparation of e.g. expanded polystyrene suitably for re-use

摘要

Recoverable plastic material, particularly expanded polystyrene, is prepared, and in particular its density is increased, by a method in which it is first ground down to particle size suitable for the end product; it is then frictionally heated and subjected to a mechanical-thermal rounding treatment.The equipment used has a closed cylndrical container (2) with temp. control jacket (14); it contains fixed (6) and moving (7,8) pins arranged in concentric circles. The latter (7,8) are mounted on a rotating disc. The wall (3) has a temp. sensor (16) connected to a regulator (15) for thermal control. An outlet (24) is at the bottom of the container and has a valve (18) with its drive (19) which is also connected to the controller (15) for the temp. The discharged material is collected below (23).