Year: 1889

page_text: I, GRANVILLE EMERSON CARLETON of Rockport in the State of Maine, United
States of America, Manufacturer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to he particularly described and
ascertained in and by the following statement:-
My invention relates to the calcination of stone in the manufacture of lime and
cement. The object of the invention is to produce a better draught and more
thorough combustion of the fuel and a more even uniform and complete distribution
of the heat in the barrel of the kiln, whereby the stone is thoroughly and properly
calcined without injury to the kiln, and whereby also economy of the fuel is secured.
My invention consists of an improved method of treating stone and in an improved
apparatus for the more effectual carrying out of the method all as hereinafter
explained.
The invention is designed chiefly for use in connection with coal as a fuel or with
wood and coal mixed. "The use of coal as a fuel in kilns for calcining limestone has
heretofore been attended with difficulty in respect to the draught and also in respect
to its action upon the stone. In my experience with this kind of fuel I have applied
a blast underneath the graic, which, while it increases the draughi, caused the heat
to act imperfectly and unevenly upon the stone in the barrel of the kiln, and by over-
heating some parts unduly injure the arches and kiln. 1 have found by further
experiment that this difficulty attending the use of the air blast may be overcome by
the use of a jet of water or steam applied in front of or over the bed of coal in the
fire chamber. The first part of my invention as set forth in this specification consists
in the method of calcining stone for the manufacture of lime and cement by means
of an air blast applied underneath and a jet of water or steam applied above the fuel
within the fire box. I have shown in the accompanying drawings the apparatus by
means of which my invention is most conveniently practised and although I do not
confine myself in all respects to the use of this apparatus, it forms the second part
of my present invention, and is shown in the accompanying drawings.
In the drawings :
Fig. 1 shows a vertical section taken through the centre of one of the arches and
heongh the barrel of the kiln.

page_text: སཔར
Fig. 3 shows a view of an arch on an enlarged scale.
Fig. 4 is a view of the opening of an arch from the inside of the same
Fig. 5 shows a perspective view of the kiln, and—
Fig. 6 a detail sectional view of a nozzle for supplying the water or steam jet.
In these drawings A represents the barrel of the kiln and B the arches. The
general construction and arrangement of these arches in their relation to the barrel
of the kiln are the same as those in ordinary use, but for the better operation of my
invention I have changed somewhat the proportions of the parts, and although do
not limit myself to the exact proportions, I have hereinafter given them, in order
that those skilled in the art may be able to better practise my invention.
I have represented the barrel of the kiln as having a rear and cross section of
5 by 7 feet. The height of this kiin is the same as those in ordinary use (about
32 feet) having the same cross section. The kiln represented is what is ordinarily
called the four arch kiln, there being four arches, two on each side, opening into the
barrel of the kiln. Each of these arches is about 30 inches in width and 20 inches
in height, being designed for coal, and therefore requiring only about two-thirds of
the height required in an arch used for burning wood. The pillar used for supporting
the arch at the opening into the barrel is represented at D. The openings don
each side of this pillar are ten inches wide and eighteen inches high, a fire bridge
about two inches in height is shown at e, being placed across the opening. The grate
shown in the plan view of the arch extends from side to side and is about 20 to
30 inches in surface area. As shown in the figures representing the front of the
arch, the door thereof is somewhat contracted. The lines E, F, represent the floor
of the arch used for wood, and the lines F, F, show the height of the floor used for
coal. The front opening of the arch constructed for coal is represented by the
lines and they are 16 inches in width by 18 in height. The upper part of this
opening is half covered by a plate which extends down to the line y g. Under the
grate is the ordinary ash pit which is closed and into it is led the air pipe from
any suitable air forcing engine. This is provided with a valve, Fig. 5 by means
of which the blasts may be regulated or altogether excluded. Through similar
branches of the main air pipe the air may be applied to the ash pit of each arch.
It will be understood that water may be introduced into the fire chamber over the
coal in any way such as by hand though that would not be the most convenient.
For greater convenience a pipe K is led across the face of the kiln just above
the door with a branch pipe leading to each mouth of the kiln, preferably
constructed so as to be swung up out of the way whenever it may be desired, the
coupling being provided as at m to allow this. This pipe is connected to any suitable
source of supply of water or steam. 1 prefer to use water as this is more convenient
and serves the same purpose as steam. I find it convenient to use the form shown
in Figs. 5 and 6 in which represents a section of the pipe nozzle with a hole at Z
on one side towards the fire. This hole may be closed or regulated by means of the
screw plug L. A plate M. is arranged preferably in a horizontal position so that the
stream of water from the hole in the pipe strikes an inclination of the plate and is
sprayed towards the coal and upon its surface where it is immediately converted
into steam and in part decomposed by the union of the oxygen with the incandescent
coal. The application of the water or steam in connection with the air blast I find
gives ample draught and volume to products of combustion at the proper temperature,
so that the stone in the barrel of the kiln is heated uniformly throughout, so as to be
uniformly and rapidly calcined without injury either to the arches or the walls of the
kilns. It will be understood that the steam or the water pipes are provided with
valves by means of which the supply may be regulated or cut off. It is well under-
stood that when the fresh supply of coal is added to the fire or when the coal is
stirred in the arch large volumes of carbon in finely divided state or of carbon oxide
are disengaged which escape and pass through the stone in the barrel of the kiln
unconsumed. In order to provide for the consumption of this carbon and carbon
oxide I provide an air pipe a leading into each arch above the fuel with suitable

page_text: valves for regulating the supply of air to the arch or excluding it altogether, and
when fresh coal is added or when the coal is stirred I turn on a blast of air in the
pipe leading into this upper part of the arch. This supplies air to the arch above
the fire bed and facilitates the burning of the products of combustion which would
otherwise be unconsumed. The attendant at the kiln may readily determine while
operating the valves and by observing the effect when he has a sufficient amount of
air for the best effects both in the arch above the fire bed and in the ash pit below
the grate. But it will be understood that the additional supply of air above the fire
bed is to be used only when additional coal is supplied.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is :-
1. The method of calcining rock in the manufacture of lime, consisting of first
introducing an air blast underneath the fuel in the kiln to increase the draught and
second introducing a spray of steam or water above the bed of coal, substantially as
and for the purpose described.
2. The herein described mode of calcining rock in a kiln having a barrel to contain
the rock, and arches leading thereto, consisting in applying the air blast below the
grate to create a draught, and applying steam or a spray of water within the arch
above the fuel to regulate the heat, as and for the purpose set forth.
3. In combination with the barrel of the kiln and with the arch or fire box
thereof, having a grate and with the ash pit thereof, an air pipe communicating with
the ash pit beneath the grate, with air forcing mechanism therefor and a steam or
water pipe arranged to discharge steam or water within the arch or fire box, and over
the surface of the fuel, substantially as described.
Dated this 10th day of ML 1000
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London,
Applicant's Agent.