For information about burning lime we republish the following article
furnished by a correspondent of the _Country Gentleman_ several years
ago:
[Illustration: Fig. 1. Fig. 2. Fig. 3. A (Fig. 1), Railway Track--B B B,
Iron Rods running through Kiln--C, Capstone over Arch--D, Arch--E, Well
without brick or ash lining.]
I send you a description and sketch of a lime-kiln put up on my premises
about five years ago. The dimensions of this kiln are 13 feet square by
25 feet high from foundation, and its capacity 100 bushels in 24 hours.
It was constructed of the limestone quarried on the spot. It has round
iron rods (shown in sketch) passing through, with iron plates fastened
to the ends as clamps to make it more firm; the pair nearest the top
should be not less than 2 feet from that point, the others interspersed
about 2 feet apart--the greatest strain being near the top. The arch
should be 7 feet high by 5½ wide in front, with a gather on the top
and sides of about 1 foot, with plank floor; and if this has a little
incline it will facilitate shoveling the lime when drawn. The arch
should have a strong capstone; also one immediately under the well of
the kiln, with a hole 2 feet in diameter to draw the lime through; or
two may be used with semicircle cut in each. Iron bars 2 inches wide by
1/8 inch thick are used in this kiln for closing it, working in slots
fastened to capstone. These slots must be put in before the caps
are laid. When it is desired to draw lime, these bars may be
pushed laterally in the slots, or drawn out entirely, according to
circumstances; 3 bars will be enough. The slots are made of iron bars
1½ inches wide, with ends rounded and turned up, and inserted in holes
drilled through capstone and keyed above.
The well of the kiln is lined with fire-brick one course thick, with a
stratum of coal ashes three inches thick tamped in between the brick
and wall, which proves a great protection to the wall. About 2,000
fire-bricks were used. The proprietors of this kiln say about one-half
the lower part of the well might have been lined with a first quality of
common brick and saved some expense and been just as good. The form of
the well shown in Fig. 3 is 7 feet in diameter in the bilge, exclusive
of the lining of brick and ashes. Experiments in this vicinity have
proved this to be the best, this contraction toward the top being
absolutely necessary, the expansion of the stone by the heat is so
great that the lime cannot be drawn from perpendicular walls, as was
demonstrated in one instance near here, where a kiln was built on that
principle. The kiln, of course, is for coal, and our stone requires
about three-quarters of a ton per 100 bushels of lime, but this, I am
told, varies according to quality, some requiring more than others; the
quantity can best be determined by experimenting; also the regulation of
the heat--if too great it will cause the stones to melt or run together
as it were, or, if too little, they will not be properly burned. The
business requires skill and judgment to run it successfully.
This kiln is located at the foot of a steep bluff, the top about level
with the top of the kiln, with railway track built of wooden sleepers,
with light iron bars, running from the bluff to the top of the kiln, and
a hand-car makes it very convenient filling the kiln. Such a location
should be had if possible. Your inquirer may perhaps get some ideas
of the principles of a kiln for using _coal_. The dimensions may be
reduced, if desired. If for _wood_, the arch would have to be formed for
that, and the height of kiln reduced.
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