US 4,439,141 AGranted

Recuperative double chamber rotary furnace

OwnerGeorge J. Deckebachinventor

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Abstract

An apparatus that is designed to heat a flowable granular material up to an elevated temperature and cool the material back down to a temperature that is as close as possible to the temperature of the incoming material before exiting, where a substantial portion of the heat transferred in both heating the incoming material up and cooling the outgoing material back down is not being accomplished by outside heat sources and heat sinks, but rather by transferring heat from outgoing material to incoming material on a more or less direct basis. This is to be accomplished by an apparatus that is comprised of two coaxial cylinders rotating about their common axis whereby feed material enters and exits from one end, and a heat source is provided at the opposite end. Feed material enters into the inner chamber and travels towards the heat source. After passing the heat source, feed material transfers to the outer chamber where it moves in a direction opposite incoming feed material and exits the same end that it entered. The feed material, before exiting, transfers a substantial portion of its heat to the incoming material, effectively recuperating heat.

Claims8

Dependent claims

A recuperative rotary furnace for treating granular material, comprising:

(a) a base;
(b) a first cylinder rotatably mounted to said base, said first cylinder having an outer diameter, a central bore, a substantially closed end, and a substantially open end;
(c) a second cylinder having an outer diameter smaller than said first cylinder bore, and further having a central bore, a substantially closed end, and a substantially open end, said second cylinder rotatably carried coaxially within said first cylinder bore and mounted with said second cylinder open end disposed towards said first cylinder closed end;
(d) an inner end space maintained between said first cylinder closed end and said second cylinder open end;
(e) an annular outer chamber maintained between said first cylinder bore and said second cylinder outer diameter, said annular chamber in communication with said inner end space;
(f) drive means for rotating said first and second cylinders with respect to said base;
(g) means for feeding granular material at a first temperature into said second cylinder bore through said second cylinder closed end;
(h) means for continuously moving granular material through said second cylinder bore towards said second cylinder open end through said end space, and through said annular outer chamber toward said first cylinder open end;
(i) means for heating granular material to a second temperature elevated above said first temperature in said second cylinder bore in a region substantially proximal to said end space;
and
(j) means for controlling the flow rate of granular material movement through said first and second cylinder bores.

8 more elements

Dependencies are inferred from the claim text.