GB1042729A - Improvements in rotary kilns - Google Patents

Abstract

1,042,729. Cooling cement clinker. F. L. SMIDTH & CO. A/S. June 15, 1965 [Aug. 20, 1964; Aug. 28, 1964], Nos. 34095/64 and 34524/64. Heading F4B. Cement clinker discharged from a rotary kiln 1 through eight openings 20 with pipes 21 spaced around the periphery of the kiln is fed via a casing 22 and shaft 23 evenly on to a cooling grate 10 disposed over plenum chambers 13a and 13b, hot air from the grate being fed through a separate shaft 8 to the kiln to support combustion therein. Air is drawn from the shaft 23 through cyclone separators 30 by fan 34 and returned through pipes 35, 36 and 37 by fans 38 and 39 back to the plenum chambers. Branch air entry pipes 40 and 41 respectively controlled by valves 42 and 43 permit control of this withdrawn air to produce a pressure in shaft 23 equal to that in the kiln, thus preventing back flow of air through shaft 23 into the kiln. casing 22 and a wall 27 encloses the space between shafts 8 and 23 to which space coolant is supplied by a pipe 28. A modification, Fig. 5 (not shown), has four openings 20 instead of 8 giving a more even distribution in the grate 10, and a further modification. Figs. 6 and 7 (not shown), has the casing 22 substituted by a part-cylindrical wall. The casing forming shaft 8 may be extended over the pipes 21 which are shortened to extend only through the kiln wall, Figs. 8 and 9 (not shown). The pipes 21 may be disposed in the dam ring 4 opening into shaft 8 which is cut off from the kiln, a separate pipe providing the passage for hot air to the kiln, Figs. 10 and 11 (not shown). Another modification, Figs. 12-15 (not shown), has a dam ring extending inwardly of the periphery at the end of the kiln 4 formed with four circular discharge ports opening into reservoirs, said ports being disposed rather towards the outer edge of the annular dam ring. The open outer ends of each reservoir has a V-shaped dam with the base of the V inwardly of the furnace. The axis of the V runs substantially diametrically of the port, but is inclined to the diameter of the ring which combined with the shaping of the dam. In a final modification, Figs. 16-19 (not shown), the discharge end of the kiln tapers down to a section of smaller diameter than the rest of the tube, and a number of reservoirs joined to ports in the tapering wall discharge through an end easing on to a cooling grate.