GB985569A - Improvements in or relating to mills - Google Patents

Abstract

985,569. Hammer mills. UNIVERSAL MILLING & MACHINERY Ltd. Aug. 24, 1961 [Nov. 4, 1960; May 6, 1961], No. 30494/61. Heading B2A. A disintegrator comprises a rotor provided with a plurality of circumferentially and axially spaced striking blades, a cylindrical sizing screen circumferentially bounding the rotor and blades at a uniform radial distance therefrom, a pair of axially spaced end walls extending radially beyond the margins of the screen and enclosing the screen to provide a comminuting chamber between the end walls, and connected with a housing spaced outwardly from the screen to form a receiver space, apertures in the screen communicating the said chamber with the said space, an aperture for feeding material through an end wall into the comminuting chamber, an exhaust aperture opening into the receiver space, gas withdrawal means connected with the exhaust aperture, and means for inducing a flow of a gas into the comminuting chamber other than through the feeding aperture. As shown in Figs. 3 and 5, material is supplied from a hopper 10 to a feed aperture 14 in an end wall 16 of a comminuting chamber 15 which has disposed therewithin a rotor 18 provided with toothed pivoted striking blades 17 surrounded by a sizing screen 25 around which is a receiver space 32 leading to an exhaust aperture 33 connected to a suction duct 34. The end wall 16 also has an injection aperture 36 of nozzle form through which a gas jet is delivered to the chamber 15 in the direction of blade motion by means of a duct 39 connected to a blower 41. The screen has over a portion of its circumference an inner sheet metal abrading member 45 provided with a pattern of triangular and circular apertures 46, 55. The screen has a net aperture ratio greater than 20% and preferably greater than 30%. The area of the apertures 45 is about 5 to about 50 times the area of the apertures in the screen. The nozzle 36 is disposed to direct the gas jet away from the end of the member 45 remote from the aperture 14. In a modification, Figs. 8 and 11, material is supplied from a hopper 112 to a feed aperture 141 in an end wall 123 of a comminuting chamber 125 bounded by a screen 128 surrounding a rotor which comprises a disc 142 and stepped radial impeller vanes 145 for inducing gas flow through a door port 161, the vanes having pivoted toothed striking blades 126 pivoted to the recessed outer ends thereof. Around the screen is a receiver space leading to an exhaust duct 158 connected to suction means. Material may alternatively be fed to the chamber 125 by means of a slide 160. The screen may be provided with an auxiliary screen over part of its inner circumference. In another modification, Fig. 14 (not shown), a hopper feeds a shoot leading to a feed aperture located within a door port for the induced air. Specification 985,568 is referred to.