GB763262A - Improvements in or relating to grinding mills - Google Patents

Abstract

763,262. Impact mills., KELLER, B., and BERNCASTLE, E. J. M. DE. Feb. 2, 1954 [Feb. 10, 1953], No. 31.22/54. Class 59 [Also in Group XXX] A grinding mill comprises a pair of bladed rotors 21, 26 disposed in chambers 14, 16 defining therebetween an interconnecting space 24a, 28a which is bounded by walls having projections 24b, 28b, the rotors being driven by motors 35 in the same direction and at substantially the same speed, and the rotor blades 24, 28 being so arranged that at a predetermined instant adjacent blades of both rotors will further bound the space 24a, 28a, and at a further instant adjacent blades of the rotors will be oppositely disposed in substantial alignment. Each motor is contained in a shell 36, Fig. 4, provided with vents 37 through which, on rotation of the rotors, cooling air is drawn, the air being expelled partly through vents 38 at the rear end of the shell 36, and the remaining air, after being drawn through a discharge opening 42 in a wall 43 at the rear of the mill housing and through passages 45a in the mill housing, being discharged through outlets 45 and 44. The ground material passes through screens 25, 34. The chambers 14, 16 are closed by a removable cover plate 30 to which are attached two branches 13, 15 of a feed conduit 50, the flow of material to the chambers being controlled by means of an angularly adjustable gate 17. Each chamber is provided with internal projections 14b, 16b. The chambers may be slightly oblong or ovate. In a modification. Fig. 5 (not shown), the rotor shafts are adjustable towards or away from each other. In a further modification, Fig. 6 (not shown), the rotor blades are angularly adjustable.