IMPROVE- MENTS IN BURNING LIMESTONE IN THE PROCESS OF MAKING LIME, AND IN APPARATUS TO BE EMPLOYED THEREIN
Year: 1880

page_text: LETTERS PATENT to Alexander McAra, of Glasgow, in the County of Lanark,
North Britain, Limo and Cement Merchant, for an Invention of "IMPROVE-
MENTS IN BURNING LIMESTONE IN THE PROCESS OF MAKING LIME, AND IN
APPARATUS TO BE EMPLOYED THEREIN."
PROVISIONAL SPECIFICATION left by the said Alexander McAra at the
Office of the Commissioners of Patents on the 31st March 1880.
ALEXANDER MARA, of Glasgow, in the County of Lanark, North Britain, Lime
and Cement Merchant. "IMPROVEMENTS IN BURNING LIMESTONE IN THE PROCESS
OF MAKING LIME, AND IN APPARATUS TO BE EMPLOYED THEREIN."
The said Invention relates to improvements in burning limestone in the process
of making lime, and in apparatus to be employed therein, by which improvements
the process of burning limestone is so conducted that the limestone is introduced
into the furnace or fluo of the kiln at the point farthest from the fire and is caused
to travel forward towards the fire, thus being submitted to the greatest heat just
before it leaves the furnace. The heat of the fuel is thereby economized to the
utinost, and the extent of burning of the limo is under complete control.
According to the said Invention the kiln is constructed with a furnace or
continuation thereof of considerable length, and the limestone is placed upon a
series of trays or wagons which are introduced into the furnace of the kiln, and a
progressive motion given to them so that they advanco slowly towards the fire, at
which point they leave the kiln, and are emptied and recharged with limestone
and replaced in the kiln to travel towards the fire as before described. The
wagons will form virtually the bottom of the furnace, and their motion may be
obtained by mounting them upon wheels which run upon inclined rails in the said
furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander McAra in the Great Seal Patent Office on the 29th
September 1880.
ALEXANDER MCARA, of Glasgow, in the County of Lanark, North Britain, Lime
and Cement Merchant. "IMPROVEMENTS IN BURNING LIMESTONE IN THE PROCESS
OF MAKING LIME, AND IN APPARATUS TO BE EMPLOYED THEREIN.”
My said Invention relates to improvements in burning limestone in the process
of making lime, and in apparatus to be employed therein, by which improvements
the process of burning limestone is so conducted that the limestone is introduced
into the furnace or flue of the kiln at the point farthest from the fire, and is
carried forward upon the travelling bottom of the kiln towards the fire, thus being
submitted to the greatest heat just or shortly before it leaves the furnace. The
beat of the fuel is thereby economized to the utmost and the extent of burning of
the lime is under complete control.
According to the said Invention the kiln is constructed of considerable length,
and the limestone is placed upon a series of trays or wagons which are introduced
into the kiln, and a progressive motion given to them so that they advance slowly
towards the fire, at or about which point they leave the kiln, and are emptied and
recharged with limestone and replaced in the kiln to travel towards the fire as
before described. The wagons will form virtually the bottom of the furnace, and
their motion may be obtained by mounting thein upon wheels which run upon
rails in the said kiln.
And in order that my said Invention may be properly understood I now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
accompanying Drawings and to the letters and figures marked thereon, that is
to say :-
し
Figure 1 represents in end clevation a kiln constructed or arranged for carrying
my Invention into effect; Figure 2 is a vertical section thereof taken on the
line 1, 2, Figure 3; Figure 3 is a longitudinal section of the end of the kiln
towards which limestone is carried; and Figure 3A is a similar section of the other
end of the kiln between the end thereof whereat the limestone is introduced and
the furnace or furnaces, a part being shown as broken away, as the kiln may be of
any convenient length, but it is preferably 60 feet in length or upwards from end
to end; Figure 4 is a plan of the said kiln drawn to a reduced scale. The kiln
consists of side walls and a roof b. The lower part of the side walls are recessed
to receive wagons c for placing the limestone upon and conveying it through the
kiln. The said wagons c are of firebrick or fireclay set in iron trays or base plates
mounted upon wheels running upon rails & laid at the bottom of the kiln. The
top plates or surfaces of the wagons c fit into the recessed lower part of the side
walls a of the kiln, as seen more clearly in Figures 1 and 2. The said top plates
or surfaces of the wagons c form, when a series of the wagons are placed end to end
in the kiln, a continuous bottom to the said kiln. A chain, indicated by the line e,
is fastened at one end to the wagon nearest to the entering end of the kiln, its other
end being connected with a winch or hauling apparatus.
In conducting the burning operation the wagons caro placed in the kiln
sufficient in number to form the floor throughout the length of the kiln, those
wagons between the fire and the entrance to the kiln having limestone to be
burned built or placed upon them, as shown in the Drawings, and the chain e
being fastened to the wagon nearest the entrance to the kiln and led to the other
end of the kiln, where it is pulled upon so as to haul forward the wagons a short
distance at a time, so that those laden with limestone pass slowly towards the fire
which is in the furnaces f, f, (furnished with firing doors, ash pits, and other usual
appliances of furnaces), the products of combustion therefrom passing by the
passages or flues f², f, into the kiln and over and amongst the limestone, the

page_text: doors g, g², respectively at either end of the kiln being closed, and the said products
escaping by a flue & which is in connection with a chimney to give a sufficient
draught. As soon as the wagons have been traversed through the kiln to a
sufficient distance to admit of the introduction of another wagon, a layer of lime-
stone is placed on another wagon c and the door g is raised and the said wagon
introduced thereinto, the chain e being taken from the preceding wagon and
fastened to the one last introduced, and the wagons are then caused to travel
through the kiln until there is room for the introduction of another wagon, when
the chain is unfastened from the preceding wagon and fastened to that last
introduced, and so on, a wagon being removed from the exit end of the kiln as
one is introduced at the other end, and thus the process is continued, the wagons
laden with limestone as they reach the door at the exit end of the kiln being
removed from the kiln, and a fresh wagon laden with limestone to be burned being
admitted at the entrance of the kiln, the process being carried on continuously, the
limestone in the process travelling towards the fire as described. The furnace or
furnaces may be either close to the exit end of the kiln or they may be at some
distance therefrom, as shewn in the Drawings, so that the burnt lime is cooled or
partly cooled before leaving the kiln. Superheated steam may be conducted into
the kiln. This may be effected by leading a pipe from any convenient source of
steam supply into a coil of piping i contained in the roof of the furnace or furnaces
(as shewn with regard to one of the furnaces in Figure 2) and furnished with
nozzles leading into tho kilu. The door g at the exit end of the furnace may be
raised to a slight extent to admit air to the kiln, which air becomes heated in
passing over the wagons, and whilst cooling the line will aid in consuming the
smoke from the furnaces.
As the wagons are withdrawn from the kiln they are unloaded of the burnt
lime and run by the rails j, Figure 4, back to the entrance end of the kiln to
receive a fresh load of limestone and be again conducted through the kilo.
By the rate at which the wagons c are caused to travel through the kiln the
degree of burning can be nicely adjusted and the burning process be conducted
with great facility.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or manner in or under which the same is or may
be used or practically carried into effect, I would observe in conclusion that what
I consider to be novel and original, and therefore claim as the Invention secured to
me by the hereinbefore in part recited Letters Patent is,-
First. The hereinbefore described improvements in burning limestone, consisting
in conveying it through the kiln or chamber wherein it is burned towards the
fire or fires by which the burning is effected upon the travelling bottom of the
kiln or chamber, whereby the process is conducted with great facility and the
degree of burning may be nicely and readily adjusted.
Second. The apparatus for burning linestone, consisting of a kiln wherein the
limestone is traversed therethrough upon the moveable floor thoreof towards the
fire in the process of burning, essentially as hereinbefore described and illustrated
in the accompanying Drawings.
Third. The combination with and use in kilns for burning limestone of wagons
or their equivalents forming the muoveable floor of the kilo, as hereinbefore
described and illustrated in the accompanying Drawings.
In witness whereof, I, the said Alexander McAra, havo hereunto set my hand
and seal, this Twenty eighth day of September, in the year of our Lord
One thousand sight hundred and nighty