Improvements in the Construction of Kilns for Burning Limestone, Cement, and other similar Material.
Year: 1895

page_text: Date of Application, 5th Jan., 1895-Accepted, 6th Apr., 1895
COMPLETE SPECIFICATION.
Improvements in the Construction of Kilns for Burning Limestone,
Cement, and other similar Material.
1, JAMES FOSTER of Carnlough Lime Co. Ltd., Carnlough in the County of
Antrim, Ireland, Lime Manufacturer 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 :-
This invention which relates to improvements in the construction of kilns for
burning limestone cement and other similar material has for its object to over-
come certain defects, and at same time attain many advantages not hitherto met
with in kilns presently in use.
It has invariably been the practice when charging such kilns with limestone or
other material to feed the fuel, for the object of calcination, in at the top or mouth
of the kiln. According to one feature of my improvements this is entirely obviated
as will be hereafter explained. A further advantage derivable from my improve-
ments being that in feeding the kilns very fine dross, slack, or coal dust may be
fed into the kiln which has the advantage of readily mixing with the calcining
mass, and at a point where more perfect combustion takes place. Other special
features are a uniform quality of lime is obtained and increased production.
All clinkering is also overcome. And further, by my improvements the first
cost of erection is considerably reduced as well as the cost of keeping the kiln in
repair.
The invention, whereby these ends are attained, consists in the form of a three
chambered kiln, the upper chamber of which is at its upper extremity of bell mouth
shape and is surmounted by an iron chimney which by its portability is easily
removed for purposes of charging the kiln. In the said upper chamber preparatory
drying or roasting of the material takes place. Ingress to the middle and lower
chambers is obtained by two concentric circles of fuel feed shutes arranged at two
distinct planes or levels. The inlets or openings of these fuel-feed shutes, at the
top thereof, are provided with automatic cones. These cones are suspended from
chains, which pass over suitable pulleys, and which are controlled by weights or
counterpoises. As an alternative arrangement, I provide a kiln which may be
said to consist of practically four chambers, and of this kilu, as in the foregoing one,
there may be a double circle of fuel-feed shutes, or only one as may be found most
desirable. The lower chamber in this kiln is the same as in the kiln already
described, but, in place of the upper chamber tapering in an upward direction, it
expands a certain distance and is then carried in a cylindrical form to the top.
Across this chamber, at a point where it begins to narrow in a downward
direction, there is an arch thrown, which is of peculiar construction and which
is carried to the top of the kiln, thereby dividing the upper chamber into two
The object
elliptical divisions making in all four chambers as already stated.
of this arch is to provide a means of "fuelling" the kiln some distance from
the top thereby providing against any waste of heat, as the heat, generated
from the combustion of the material supplied through the side flues, and the flue
or flues formed in the arch, having to pass through the two divisional chambers
at the top of the kiln in which a constant supply of raw material is always
maintained. The raw material in the said two divisional chambers absorbing the
heat generated from below becomes partially calcined before descending to the
lower chambers where the calcining proper takes place. This arch with extended

page_text: wall is so constructed that it readily and effectually resists the pressure of the
material exerted laterally in its descent into the kiln. In accordance with this
arrangement no fuel goes in at the top the advantages due to which are a great
saving of fuel and that the material receives the same treatment and is therefore
uniformly burnt. The middle chamber and the two upper chambers are so nicely
formed that the material in its passage down into the kiln through narrow dome
like opening between the lower and middle chambers will not adhere to, rest on,
.norget attached to the-sides- of--the kiln nor 'jam' in its descent. In order
that my invention may be properly understood and readily carried into effect
I have hereunto appended two explanatory sheets of drawings in the several
figures of which corresponding parts are marked with the same letters of
reference.
,
Eig. is a vertical section of a kiln made in accordance with and constituting
part of my invention. Fig. 2 is a horizontal section of a part of the same taken
on the lines a, b, passing through the blocks which carry or support the upper
portion of the kiln.
Fig. 3 is a detail view, drawn to an enlarged scale, of an automatic device for
closing and opening the fuel-feed shutes.
Fig. 4 is an alternative arrangement of kiln made in accordance with and con-
stituting the other part of my invention and 'hereafter more fully described.
Fig. 5 is a horizontal section of the same.
1
In Figure 1, the upper chamber of the kiln which is made slightly taper and
having a bell mouth opening is "marked A, the middle chamber B, the lower
chamber C. The said upper chamber B, is built on blocks C', while-the said
chamber A, which slightly overlaps chamber B, is built on the blocks B'. The
said, upper chamber A, is provided with a portable chimney marked D, which
may be of wrought iron, steel or other suitable metal. The said chimney D, is
easily removed, as has been briefly referred to; for the purposes of charging the
"kiln by any well known mechanical means: "for instance the said chimney could
.be suspended. by a derrick or bracket after the manner of a ship's davit and by a
suitable lever arrangement could be easily slued to the one side of kiln and
again replaced. The object of the chimney is to increase the draught in kiln and
to carry away the smoke and gases.
"
Two circles of fuel-feed shutes E, and F provide-means whereby the kiln is to
be fed; a small portion of fuel going in at the top. The shutes. E, supply fuel to
the chamber C, whilst those marked F, supply fuel to the middle chamber B.
Fuel in a state of fine division can be used with great advantage, especially in the
fuel shutes as it readily becomes mixed with the stones or other material under
treatment. The shutes E, and F, are at their 'outer ends provided with hoppers G.
These hoppers G, are closed and opened for feeding purposes by the cones H.
chains 1, and counterweights J. The said chains I, and weights J. are carried
round the pulleys K which may be mounted on a bracket, or on a rod L, as shewn
in Figure 1.
The kiln represented in Figure 4, Sheet 2 has four chambers A, B, C, and D.
The lower chainber D¹ is fed through shutes F, and the middle chamber C, as
well as the lower chamber 'D' through the' shute F, which passes through the
centre of the arch which I shall now proceed to describe. By the two upper
elliptical chambers A, and B, formed by the arch the raw material alone is fed,
and the two said chambers A, and B, are always maintained filled to the top for
purposes already stated. The brick chimney D, with which the top of this kiln
is surmounted is provided with openings D², and D³, immediately over the elliptical
chambers A, and. B, for the purpose of feeding the kiln as shewn in the drawings.
These openings after the feeding operation has been completed may be closed by
suitable doors but where draught is good 'these are unnecessary. The arch A¹,
aforementioned in Fig. 4 of the drawings, has a superimposed partition wall A²,
which is made narrowest at the centre expanding towards the sides of the kiln and
which by virtue of its construction affords complete resistance laterally to the

page_text: pressure of the material in passing into the kiln. The said arch A', is faced with
fine brick on all sides while rubble or concrete may advantageously be used for the
core.
It is to be understood that the fuel-feed shutes as illustrated by the letters E,
and F, do not in themselves form novel features of my improvements but the
arrangement of these in two concentric circles &c., as set forth with reference to
Figure 1, forms an essential feature of my present invention as also does the
arch &c., as illustrated in Fig. 4.
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 I
claim is:-
1. In combination with a three chambered kiln for burning or calcining lime
cement or analogous ores two concentric circles of fuel feed shutes preferably
at different levels, for the purpose of feeding fuel into the middle and lower
compartments at the point of intensest heat, substantially as set forth.
2. In combination with the fuel-feed shutes E, and F, the automatic device,
consisting of a hopper G, cone H, chains I, and counterweight J, for opening and
closing said shutes for the object of feeding fuel into the kiln in very small
quantities and for preventing any undue escape of heat; for maintaining a good
draught in kiln and directing it toward centre, in these ways effecting a saving in
fuel and giving a greater uniformity in quality and larger output of lime as
set forth.
3. In combination with kiln illustrated in Fig. 1, the portable chimney D,
constructed of wrought iron or other suitable metal or material substantially as set
forth.
. 4. In combination with a four chambered kiln as illustrated in Fig. 4, the
arch A', of novel construction and brick chimney D, as before described for
providing a means for "fuelling " kiln at some distance from the top by means of
the fuel-feed shutes thereby effecting, a great saving in fuel and ensuring a uniform
quality of burnt material by the continuous and regular manner of feeding
substantially as set forth.
Dated this 27th day of December 1894
JAMES FOSTER,
Carnlough, Ireland.