Installation and method for pulverizing and comminuting thermoplastic material

摘要

915,255. Pulverizing thermoplastic material. JAECKERING, G., [trading as JAECKERING MUEHLENUND NAEHRMITTELWERKE, H.]. July 26, 1961 [Oct. 25, 1960], No. 27029/61. Class 59. A process for pulverizing and comminuting thermoplastic material comprises subjecting the pre-crushed starting material to a whirling and comminuting operation in a gas flow with an admixture of gas of at least 30,000 parts by volume at atmospheric pressure per part by volume of starting material, the operating time being not more than 1.2 seconds. The gas is air and the upper admixture limit 90,000 parts by volume. The grain size of the pre-crushed material is between 5 and 10 mm. while the upper grain size limit of the finished material is from 0.4 to 0.5 mm. As shown, pre-crushed material is fed through hopper 2 and valve 3 to a comminutor 1 comprising plates 1a which sweep past a fluted stator 1b, a blower 1c and air inlets K. The comminutor is connected to a cyclone separator 4, the comminuted material from which passes to a grading screen 5 the oversize from which is returned to the inlet of the comminutor or is passed to a second comminutor 7 provided with air inlets K. Air leaving separator 4 passes to a filter 6.