GB842401A - Improvements in and relating to apparatus for washing coal, ore or the like - Google Patents

Abstract

842,401. Washing granulated materials. COPPEE CO. (GREAT BRITAIN) Ltd., and SANSAM, W. May 2, 1958 [May 6, 1957], No. 14401/57. Class 82(2) In a pulsating type jig for washing coal or ore, the depth of the shale bed X-X formed on a perforated grid 2 in the wash box 1, is regulated by an extractor rotor 5 driven by electric motor 6, the operation of which is automatically controlled according to the pressure at the underside of the grid 2, the pressure variation being transmitted via conduit 8 and pipe 9 to a pressure responsive mechanism which rotates pointer 10 over dial 11 to either open or close an electric circuit to the motor via contacts A or B. -When the depth of shale has increased beyond a predetermined maximum, the resultant pressure increase in conduit 8 is sufficient to rotate the pointer 10 to engage contact A which then closes the electric circuit to motor 6 through a relay R (Fig. 2, not shown). Shale is thus extracted from grid 2 until the depth of bed is reduced to the required minimum value when the pressure will have been reduced sufficiently that contact B is engaged by pointer 10, the electric circuit is opened and the extractor rotor 5 is stopped. In place of automatic operation the extractor may also be manually controlled by incorporating another switch in the circuit. In another modification the shale extractor may be continuously operated through infinitely variable gearing at a speed automatically regulated according to the pressure at the underside of the bed, the depth of bed thus being kept constant.