GB469068A - Pulveriser - Google Patents

Abstract

469,068. Jet pulverizers ; endlesschain conveyers. GRAEMIGER, B. Dec. 19, 1936, No. 34977. Convention date, Dec. 21, 1935. [Class 59] [Also in Group XXX] In a jet pulverizer the nozzle or nozzles for the gas stream which lead into the periphery of the pulverizing chamber are located substantially tangentially to the wall of the pulverizing chamber, and the supply means for the raw material lead to the middle of the pulverizing chamber. As shown in Fig. 3 an air jet through nozzle or nozzles 23 circulates around a circular or polygonal chamber 20 which may have pins inserted through the walls or contain balls Material is fed to the centre of the chamber which may contain a fixed or movable conical member 37 and around which the material is displaced so that it is entrained by the air and projected onto the wall of the chamber either to be broken at impact or disintegrated in the subsequent frictional contact with the walls. The disintegrated material is carried up by the air blast through an annular orifice 26 into the outer chamber 29 of a separator 27. After passing through adjustable vanes 44 the material separated out falls into the inner chamber 30 and the fines ascend through divergent outlet 45. A central pipe 31 conveys fresh feed from a bunker 36 to the side of the chamber 30 from which it is fed into the pulverizing chamber 20 together with the coarse material separated out. The central feed pipe 31 may pass outside the chamber 30 so that the material separated out is kept separate from the fresh feed. The vanes 44 may be dispensed with and the outlet 45 may be made adjustable. In Fig. 9 the fresh material is supplied to a central hole in the bottom of the chamber 20 by means of a chain conveyer 104 supplied with material from a hopper 101, the upper and lower runs of the conveyer being separated by a partition bulged at 108 to raise material into the pulverizing chamber 20. The coarse material separated out in the chamber 30 of the separator 27 falls down onto the conveyer and is carried forward over the end 109 onto the lower run of the conveyer by which it is raised over the upturned end 112 of the partition and is carried into the hopper 101 by the upper run of the convever. The amount of material drawn from the hopper 101 is thus regulated according to the amount of returned material already in the conveyer and an automatic regulation of feed is effected. The size of the inlet end of the nozzle 23, Fig. 3, may be regulated by an adjustable hinged flap or by a sliding wedge-shaped member. Fig. 8 shows an arrangement of two pulverizing chambers 90, 96 in series, the material disintegrated in the chamber 90 by the jet 97 passing through an annular orifice 93 and impinging on an impact plate 95 before being engaged by the air jet entering through nozzle 98, the ground material being discharged through orifice 99. The outlet from the mill may be regulated by an iris diaphragm and-recesses may be made in the pulverizing chamber to receive tramp iron.