| 摘要 |
1322313 Preheating and burning cement F L SMIDTH & CO A/S 2 Dec 1971 [19 Jan 1971] 2604/71 Heading F4B During the manufacture of cement using raw materials containing alkalies and/or chlorine compounds burnt in a rotary kiln 1 associated with a suspension preheater 3, a proportion of the gases formed are removed from a stationary casing 15 around the upper part of the kiln and then pass in turn through a separator 18, a cooler 19 with a water spray 21 and a fan 17 before reaching an electrostatic precipitator 11. The main stream of gases passing through the preheater formed by interconnected cyclones 4-7 is driven by a fan 10 through the precipitator. Within the casing 15 the kiln is formed with grid-covered openings 14 leading to elongated tubes 23 which prevent loss of material. In a modification (Figs. 4 and 5) the tubes (24) are provided inside the kiln and the casing is divided by pivoted flaps (30) so that gases can only escape through the openings passing through the upper part of said casing. Another modification (Figs. 6 and 7) has radially extending tubes (31) inside the kiln for the gas removal. A final modification (Figs. 8 and 9) has similar tubes containing built-in chains (36) and formed with external air jackets (32) through which atmospheric air enters to mix with the exciting gases. |
