GB1029149A - Epicyclic dieface cutter for pelletizing thermoplastics - Google Patents

Abstract

1,029,149. Pelletizing. DOW CHEMICAL CO. Aug. 12, 1964, No. 32807/64. Heading B5A. Extruded plastic material, e.g. polyethylene, polypropylene or polystyrene, is pelletized by a cutter having rotating blades mounted upon a head which rotates relative to the blades. In the embodiment illustrated in Fig. 1 (not shown) material extruded from die 24 is cut by circular blades 22, mounted upon shafts 20, which are carried by a rotating cutter head 12, the blades being rotated relative to the cutter head by air motors 18. Each shaft 20 is at an angle to the front face of head 12, the cutting edges of the blades being so disposed as to cut in a path parallel and just removed from the front face of the die 24 (see Fig. 3, not shown). In an alternative embodiment illustrated in Fig. 4 (not shown) the cutter head 32, carrying knives 40 on shafts 38, is rotatably mounted, by balls 34, on a shaft 36, on which a mixer 46 and the die plate 44 are journalled. The shaft carries a ring gear 50 which engages gears 48 carried by shafts 38, so that, upon rotation of the head 32 by, e.g. belt 52, the knives are rotated relative to the head and the shaft 36 is rotated in the opposite direction of the head, material issuing from apertures 42 thus being pelletized. In further embodiments, the extrusion apertures may be carried upon the curved face of a cylindrical die or frusto-conical die, the knives being suitably mounted upon rotating head members (see Figs. 5-8, not shown).