GB1070535A - Improvements in and relating to the grinding and dispersing of pigments in a liquid medium - Google Patents

Abstract

1,070,535. Ball &c. mills; mixing appliances. J. H. J. WOOD. Nov. 27, 1963, No. 46908/63. Headings B1C and B2A. In apparatus of the kind set forth in Specification 848,514, the number of grinding elements is only sufficient to form, when centrifuged against the cylinder surface 2 by rotation of the rotor 6, a single layer against the cylinder surface and the deflecting members 8 and less than the number which could be accommodated in such a layer and such as to permit the grinding elements to approach and recede in relation to one another during operation of the apparatus. The members 8 are blades, Fig. 2, each having a sharp leading edge 10 and a blunt trailing edge 11. The width of the members 8 i.e. from leading to trailing edge is substantially equal to the width of the spaces between them or is not greater than 10% wider or less than 10% narrower than the width of the spaces. The width of the members 8 is not less than four times, and is preferably at least eleven times, the diameter of the grinding elements which is preferably between 1/16 and 1/2 an inch. The members 8 have tongues at their ends which loosely engage grooves in end flanges 7 of the rotor. The inlet to the cylinder has an adjustable valve 14. The rotor has a scraper blade 19 for assisting the removal of the treated film or layer from the cylinder surface. The rotor is driven from a motor through a friction clutch. In operation and as shown in Fig. 2, the direction in which the grinding elements rotate about their own axes is reversed both while they roll on the cylinder surface and while they are driven by the members 8 so that the grinding elements undergo successive phases of deceleration and acceleration about their own axes in their orbit.