Patent GB-696950-A (GB)
Title: Improvements in and relating to pulverizing apparatus
IPC: B02C15/06
Filed: 1950-04-19
Abstract: 696,950. Pulverizing apparatus. FOSTER WHEELER, Ltd. April 19, 1950 [April 19, 1949], No. 9666/50 Class 59 A pulverizing apparatus comprises a casing having a pulverizing chamber therein to which material to be pulverized is fed by gravity, a number of substantially laterally adjoining pulverizing ring elements freely mounted on and in frictional driving engagement with one or more driving rollers rotatably mounted in the pulverizing chamber, the rings being adapted when caused to rotate by rotation of the rollers to move laterally and rotatively relatively to one another, means for classifying the pulverized material, and means for causing a gaseous stream to pass through the casing to remove the pulverized material therefrom. Material is fed down shoots 34, 35, in a casing 10 through gate-controlled openings 36 to preliminary grinding chambers 30, 31 at the bottom of the casing and spaced on either side of a main chamber containing roller-and-ring grinding means. This means comprises a number of flat, vertical and coaxial grinding rings 13 supported and driven by two rollers 15, which rings support at their lower parts and rotate a free crushing roller 25. The material is broken up in the preliminary grinding chambers by projections 28<SP>1</SP>, 29<SP>1</SP> on axial extensions 28, 29 of the crushing roller 25 and passes then into the main grinding chamber where it is further crushed between the rollers and ring assembly and pressed outwards between the rings which, owing to the shape of the rollers and the choice of internal diameters of the rings, are pressed towards one another and rotate at different relative speeds. Lugs 14 on the rings 13 serve to break up material accumulating in a trough 33 in which the rings rotate, uncrushables therein being gradually moved to a trap 79. Various forms of rollers and rings may be used in place of those shown in Fig. 1, see for example Figs. 6-8 (not shown). One supporting and driving roller only may be provided'. Fines from the main crushing chamber are drawn, by a stream of air entering the casing above the grinding zone at 72, up into shoots 59, 60 and into an exhauster chamber 47 whence the finest particles are discharged through an outlet 80. The heavier fine particles in their passage from the shoots 59, 60 to the exhauster chamber 47 being separated out, fall down shoots 69, 70 to the grinding chambers 30, 31, as the air steam passes from outlets 67, 68 of these shoots round the curved top of the casing 10 and around baffles 50, 51 and through passages 48, 49 to the exhauster. Damper controlled air passages 55, 56 in the top of the casing connect the passages 48, 49 direct to the atmosphere. In a modified apparatus, Fig. 9, air entering the casing at 92 carries fines up a passage 102 and around a baffle 97 where heavier particles fall down a passage 102, back to the grinding zone, the fine particles being carried through a passage 98 to a cyclone separator 99. In a further modification, Figs. 10, 11 (not shown), air is blown into the casing above the pulverizing elements to carry pulverized particles therefrom up and around classifying baffle means to an outlet.