GB699107A - Improvements relating to plants for the treatment of bulk material - Google Patents

Abstract

699,107. Cooling furnace charges. SMIDTH & CO. AKTIESELSKAB, F. L. Dec. 29, 1950 [Dec. 30, 1949], No. 31616/50. Class 51(ii) [Also in Group XXX] A plant for the treatment of bulk material by the passage of gas through it comprises an endless gas-permeable conveyer having upper and lower runs, means for feeding material to the upper run, .means for transferring to the lower run material which has been conveyed by the upper run, so that the material is conveyed in the reverse direction by the lower run, and enclosed air chambers serving to supply gas to and receive gas from the layers of material on the two runs, the chambers being so disposed that gas is caused to pass through the layer of material on each run either as a single stream through both runs in series or as two separate streams, one through each run. As shown applied to the cooling of cement clinker discharging from a rotary kiln the clinker travels along the upper run 15 of an intermittently driven conveyer and then along the lower run 16 before being discharged through an opening 26 cooling air being passed through both runs. Boxlike structures 6, 11 with perforated tops 7, 10, are provided to support the respective runs 15, 16, for the greater part of their travel. Cooling air is supplied by fans or other devices to the boxes 6, 11, and flows upwards through the tops 7, 10, the conveyer runs 15, 16, and the material thereon. The air passing through the run 15 enters a chamber 24 and flows to the kiln to support secondary combustion whilst the air passing through run 16 enters a chamber 21 connected to the burner 29 by a pipe 28 which also leads to a chimney. The chamber 21 is also connected to the chamber 24 by damper controlled ducts 22 so that air from the chamber 21 may be used for either primary or secondary combustion or both. Clinker too large to pass through the conveyer on to the lower run 16 drops down a shoot 33. The conveyer drive is effected by driving the roller 14 through a ratchet mechanism 17 by a reciprocating piston which moves in a pivotally mounted cylinder 18. In a modified plant, Fig. 3, crushing apparatus 32 is placed between the upper and lower runs 15, 16. A screen may be provided between the run 15 and crusher 32 to allow undersized material to pass directly to the lower run 16. A screen may also be provided without a crusher fine particles being then removed by screening so that only larger particles are delivered on to and treated on the lower run The invention may be applied to the preheating, calcining or burning of raw cement whilst in metallurgical processes ores may be similarly treated. Cement may. be artificially aged by blowing CO 2 through it. Air or gas may be forced through material to remove undesirable constituents, e.g. dust. The material may be transferred from upper to lower runs by scrapers and a hopper &c. The crushing apparatus may be placed outside the conveyer. Specification 699,108 is referred to.