Patent GB-716361-A (GB)
Title: Improvements in or relating to grinding materials
IPC: B02C17/16
Filed: 1949-05-24
Abstract: 716,361. Ball mills. SZEGVARI. A. July 5, 1950 [May 24, 1949], No. 13893/49. Class 59 [Also in Groups XXIV and XXIX] In a process for the fine grinding of material, a mass of spherical elements of approximately the same diameter are contained in a vessel and are agitated by means moving through the mass to such an extent as to keep substantially all the elements out of static contact with adjacent elements and in substantially constant motion so as thereby to exert attritive action on material present in said mass of agitated elements. In the apparatus shown, for the dispersion of. finely ground solid particles in a liquid, a vessel 1 provided with a jacket 2 is supported on trunnions 3, 4, which are supported in bearings in triangular side plates 5, 6, respectively. These side plates are supported on grooved wheels 10 which are adapted to be rolled along a track 11 such that the vessel may be placed under drive means for grinding purposes or brought forward for discharge purposes. A flexible conduit fastened to an opening 12 supplies hot or cold water or other liquid to the jacket 2 to provide temperature control. The jacket may be drained through a valve-equipped hose 13 into a receiver 14. The agitating means consists of an agitator comprising arms 16, 17, 18, 19 and 20 mounted on a shaft 15 and it is solely supported by the coupling which holds it to a drive shaft 22 which is driven by a motor 23 through the worm gear. The eight arms 17, 18, 19, 20 are arranged in diametrical pairs the vertical distance between the arms of each pair being not more than three element diameters. For coupling purposes the shafts 15, 22 are provided with discs 55, 56 respectively at their adjacent ends and these discs, and hence the shafts, are secured together by three toggle couplings each comprising a member 63 pivoted to a boss on shaft 22 and a pivoted member 70 provided with a set screw 74 which in clamping position is brought to bear beneath the lower surface'.of the lower disc 55. During the grinding operation the liquid in the vessel 1 is circulated by a pump 30 which draws it off through a conduit 32 and passes it back via conduit 33 to the vessel through the outlet valve 34. This valve comprises a tubular casing 125 in which is mounted a shaft 110 rotatable by a handle 111. The shaft carries two scraper bars 116 and a plate 102, Fig. 11, formed with slots 105 and pins 107. An outlet aperture in the wall of the vessel 1 is provided with a screen 101 and a plate 100 formed with slots 108 and pins 104 such that on assembly of the valve the pins 104 of plate 100 engage slots 105 of plate 102 and pins 107 of plate 102 engage slots 108 of plate 100 thus by suitable rotation of the shaft 110 the valve may be completely on partially closed the accumulation of sludge in the slots and on the walls of the casing 125 being prevented by pins 107, 108 and scrapers 116 respectively. During grinding the vessel 1 is locked in an upright position. On completion of grinding the vessel may be emptied either by dumping or by discharge through the valve 34 and outlet 37. If the former is necessary the shaft coupling is broken, the vessel moved forward on its tracks 11, and, by actuation of handle 50 and worm gearing 51, tilted, the grinding elements being retained in the vessel by a screen which is-placed across its top. Discharge may also be effected by reversing the pump 30 and disconnecting the conduit 32 from the top of the vessel the contents of the vessel then passing through the valve 34 and outlet 36 to the conduit 33.