Limestone, Lime, and similar Materials.
Year: 1887

page_text: Limestone, Lime, and similar Materials.
I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention relates to an improvement upon the kiln or furnace for burning lime-
stone, cement, and similar material described in the specification of Letters Patent
No. 1578 of 1883 wherein the charge is heated before adding the fuel. The main features
of this kiln consisted of a preliminary heating chamber, a channel or neck, and a firing
and coaling zone.
Experience has shown that the height required. for the preliminary heating chamber
in order to secure as complete a utilization as possible of the gaseous products of com-
bustion has the effect of so far crushing or caking the soft materials in the lower
portion of the chamber that the interstices between the material are contracted and
prove insufficient to allow the gases a free vent and passage.
To obviate this disadvantage and for a further advantageous purpose, I construct
the kiln as shown in the accompanying drawing forming part of this specification and
in which
Fig. 1 is a sectional elevation of same.
Fig. 2 is an end section on the line e de fand Fig. 3 is a sectional plan of Fig. 1
on the line h.
The preliminary heating chamber as shown is constructed in two parts A¹ and A,
connected with one another by means of the sloping passage B. At this point is an
opening through which the charge can be raked forward out of A¹ or B', and
through which in case of need coal can be introduced. Where it is desired to burn fine
material such as precipitated lime, the preliminary heating chamber is first charged
with largish pieces of lime stone or of other material and the intervening gaps are then

page_text: filled in with fine materials it is desired to burn, leaving however sufficient interstices
for the gases to pass through.
In a space filled with stones measuring from say 120 to 150 millimetres in diameter,
there are about 70% of empty interstices, two thirds of which may be charged with
the fine small materials and the remainder will be found sufficient for the gases to pass
through.
To this end the lower portion of the kiln is constructed with two chambers or
shafts CD and C and D which are worked in the following manner-The chamber A A'
is charged with the rough stones, the supplementary chamber CD being filled with
fine small material from the opening L' to the grating R R. The chamber CD being
charged with stone and fuel in alternate layers, and the fire is kindled from the
opening L
When the fire has burned through to the top of the chamber C the
contents of the shaft CD will have settled down enough to admit of filling in from
above. Fuel is then shot in through the opening E, and space C is again charged in
layers with the fuel and the rough material which has been previously heated in the
neck B and chamber A. The fine material to be fired is shot in through aperture J
or E in such quantities as to preserve sufficient space between the rough stones.
Owing to its fine division the small material will glow sufficiently in a very short time
from the action upon it of the gases passing through A, falling downwards with the
rough stone and dropping in its passage over the grating RR, into the shaft C¹ D¹
while the rough stone is raked through the openings E' and E towards the shaft CD
there to be burnt as described.
By carefully studying the average dimensions of the rough stone and contriving the
simultaneous and equal progression of the rough and the fine stuff, one part of fine
stuff can be kilned to every two parts of the rough stones.
If at short intervals the charge be raked and poked with iron rods which can be
introduced into the spaces B A through the doors EF and F the dropping of the
fine stuff through the gaps intervening between the rough stones can be accelerated,
and thus the proportion of fine stuff burned as compared with the rough stone will be
increased.
The rough stone can be continuously fed into A after the first firing, the heat
absorbed by it on each occasion not being lost because the corresponding amount of
heat is given off from the material when it reaches the cooling chamber D and said
heat is utilized for further kilning purposes.
Suitable apertures are arranged near the grating R R for the purpose of clearing it
and at various parts of the furnace for raking forward the material and clearing away
obstructions. The clearance opening L is hermetically closed during the firing stage.
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed, as communicated to me by my foreign
correspondent, I declare that what I claim is:-
1. In a kiln or furnace for burning limestone, cement and similar material a pre-
liminary heating chamber divided into compariments placed one above the other but
out of direct line substantially as described and for the purposes set forth.
2. In a kiln or furnace for burning limestone, precipitated lime, cement and similar
material, the supplementary chamber CD having a grating R R for the purpose
of separating and burning different grades of material substantially as described.
3. In a kiln or furnace for burning limestone, precipitated lime, cement and similar
materials the combination of the divided preliminary heating chamber, the main
chamber CD and the supplementary chamber CD, substantially as described and
for the purposes set forth.