1483135 Wet separating KAMYR Inc 30 Jan 1975 [31 Jan 1974 20 Jan 1975] 4102/75 Heading B2H [Also in Division C5] A method of delivering to a gasifier vessel 10, Fig. 1, coal, oil shale or lignite of particle sizes falling within a predetermined range of sizes (free of fines), the lower limit of which is approximately “" nominal diameter e.g. in the range “"-2" nominal diameters involves the establishment of a continuous flow of liquid (water or oil and light tar) along a first continuous flow path 20 at low (atmospheric) pressure, feeding coal or like particles from a hopper 42 downwardly through the free surface of the liquid in the chamber 50 forming part of the first flow path, transferring coal particles of the required size in incremental volumes of liquid into a second continuous flow path of liquid 26 at elevated pressure by use of a sluicing aparatus 30 (described below) provided with a screen 92 of the requisite size, and conveying the particles in the liquid of the second flow path by line 70 to a mechanical separator 32 mounted at the inlet 12 to the gasifier vessel 10. In the separator the particles are moved by a screw conveyor 96 upwardly through the free surface of the liquid, thereby falling into the inlet 12. Liquid and entrained fines passing through a screen 98 surrounding the screw conveyor, flow along line 102 to a centrifuge 36 where such fines are removed. The purified liquid is pumped back to the sluicing apparatus. Entrained fines in the first liquid flow are similarly removed by centrifuge 34. The apparatus includes provision for counteracting the net loss of liquid, particularly from the second flow path to the first. The sluicing apparatus, Figs. 2 to 4, consists of a pocketed wheel 72, see Fig. 4, mounted for rotation within a liner 76 having ports 78, 80, 82 and 84 which register with the inlets 52, 64 and outlets 58, 68 to the apparatus, in the first and second flow paths, respectively, see Fig. 2. During filling of a pocket 74 in the rotating wheel 72, fine coal particles are drawn through the peripheral slots in the screen 92. The liner may be provided with peripherally projecting grooves 94 acting as flow breakers adjacent the port openings 80 and 84 of the second flow path. The pocketed wheel 72 may be either cylindrical or tapered with the wheel diameter increasing in the direction of a clearance adjusting hand wheel 88, Fig. 3.