GB159925A - Improved process and apparatus for pulverizing or fine grinding - Google Patents

Abstract

159,925. Seymour, F. Nov. 7, 1919. Impact pulverizers.-In a process and apparatus for pulverizing or fine grinding by means of beaters mounted on discs rotating rapidly in coaxial chambers separated by peripheral diaphragms having axial openings for the passage of air and the material being pulverized, a flow of air and solid material is produced longitudinally through the chambers and the material is subjected to successive transverse selective pulverizing actions in a tubular air current therein, the shell of the tubular air current being relatively thick and substantially unobstructed towards the beginning of the pulverizing operation and thin and longitudinally undulating towards the end of the pulverizing action. The machine may have pulverizing-chambers 3 - - 6, Fig. 1, of progressively larger diameter, the openings 9, 10, 11, 12 of the diaphragms being all of the same or nearly the same diameter while the disc 18 in the first chamber 3 is relatively small, leaving a wide margin between it and the diaphragm opening out of that chamber, and the discs 18 - - 21 being progressively larger until in the last chamber 6 the disc 21 is as large or nearly as large as or larger than the diaphragm openings into and out of that chamber. Or, as shown in Fig. 2, the pulverizing-chambers 3 - - 6 may be of the same diameter, the discs 18, 19, 20, 21 being of about the same diameter and the outlet opening of the diaphragm 9 in the first chamber 3 large so as to leave a wide margin between the opening and the disc 18, while the diaphragm openings are progressively smaller until they are about the sama size as the discs. In either case, the margin between the discs and the diaphragm opening is relatively large in the first chamber and progressively less towards the last chamber, so that the shell of the air tube becomes thinner and thinner with more pronounced radial bends. The corrugated paddles or beaters 22 are carried on rigid or swinging arms extending from the discs, which are secured by shearing-bolts 24 to hubs 23 on the shaft 14. Retaining-rings 25 secured bv screws 26 hold the discs on the hubs after the bolts 24 have sheared due to an obstruction entering the machine. The paddles may be bolted to angle-iron palms 28 riveted to the ends oi the arms, or formed with rear or edge lugs through which securing-bolts pass. Or the paddles may be secured directly to the discs. A fan chamber 8 and an auxiliary air-chamber provided with air inlets 32 fitted with dampers 33 are provided at the discharge end of the machine. The pulverizing and fan chambers are lined with plate linings 30 bolted or riveted to the shell 2. The coal &c. to be pulverized is fed through a shoot 34 from a feeding-device.