GB840483A - Improvements in pulverising mills - Google Patents

Abstract

840,483. Ball-and-ring mills: centrifugal separators. BABCOCK & WILCOX Ltd. Feb. 11, 1959 [Feb. 12, 1958], No. 4617/58. Classes 23 and 59 A ball-and-ring mill comprises an annular grinding zone provided by a circular row of grinding balls 5 disposed between an upper rotary grinding ring 3 and a lower non-rotary grinding ring 4, a windbox 51 for directing entraining elastic fluid upwardly through an annular zone surrounding the grinding zone, means comprising bosses 10, 14 for rigidly connecting the grinding ring 3 to a drive shaft 15 which passes through bearing means including a thrust bearing 18 adapted to withstand upward force on the drive shaft, and spring-loaded tension rods 56 for urging the lower grinding ring towards the upper grinding ring. The upper grinding ring is located in relation to the drive shaft 15 by means of removable spacer rings 27 each comprising a plurality of separate segments mounted between flanges 12, 23 on the bosses 10, 14. A rotatable collector disc 38 is mounted below a support ring 28 for the lower grinding ring and a deflector member 46 has its upper edge secured to the upper part 1 of the mill housing and its lower edge disposed closely adjacent to the outer part of the disc 38. The support ring 28 is provided with a baffle member 30 having a downwardly extending lip 31. The base part 2 of the mill housing is provided with a guide member 32 having flanges 33, 34, the guide member being provided at the flange 34 with a stuffing box 35. The upper end of the guide member is provided with a U-shaped flange 36 which provides a recess for the lip 31. A flexible member 37 is connected at its outer edge to the lip 31 and at its inner edge to the stuffing box 35. The support ring 28 is provided at its lower side with a hinged plough which co-operates with the disc 38 to move foreign matter into a hopper 48 leading to a bin 50<SP>1</SP>. The elastic fluid, suitably heated air under pressure, supplied from the windbox 51 is directed radially inwardly between the flange 33 and the ring 38, is then guided upwardly by the member 32 through an opening 39 in the disc 38 and then directed radially outwardly between the disc 38 and the support ring 28. The fluid is then diverted upwardly by the member 46 to pass through a passage 54 between the grinding ring 4 and a fixed guide ring 53 and then passes upwardly to a classifier 62. The ring 53 may be replaced by a movable guide ring rigidly attached to the lower grinding ring by circumferentially spaced radial webs extending across the passage 54 and in this case sealing means 55 are provided. The classifier 62 is surrounded at its lower part by a baffle member comprising a fixed casing 77 and an adjustable casing 78. The classifier is provided with a collector 73 having radial outlets 76 for discharging coarse material towards the grinding zone. Material to be ground is fed from a rotary table type feeder 81 through an aperture 80 and down a shoot 82 to the grinding. zone. Specification 523,770 is referred to.