IMPROVEMENTS IN LIME KILNS, APPLICABLE ALSO FOR CALCINING CEMENT, ORE, OR OTHER PROVISIONAL SPECIFICATION
Year: 1881

page_text: LETTERS. PATENT to Edward Crosland, of Arnside, near Milnthorp, in the
County of Westmoreland, Civil Engineer, for an Invention of "IMPROVEMENTS
LETTERS. PATENT to Edward Crosland, of Arnside, near Milnthorp, in the
County of Westmoreland, Civil Engineer, for an Invention of "IMPROVEMENTS
IN LIME KILNS, APPLICABLE ALSO FOR CALCINING CEMENT, ORE, OR OTHER
PROVISIONAL SPECIFICATION left by the said Edward Crosland at the
Office of the Commissioners of Patents on the 29th April 1881.
EDWARD CROSLAND, of Arnside, near Milnthorpe, in the County of West-
moreland, Civil Engineer. "IMPROVEMENTS IN LIME KILNS, APPLICABLE ALSO
FOR CALCINING CEMENT, ORE, OR OTHER MATERIAL.”
My Invention relates to a construction of kiln in which continuous calcining of
lime, or of cement, ore, or other material is effected by the combustion of gas from
a gas producer, or by hydrocarbon vapour or spray. The kiln which I employ
widens out from the bottom to a certain height and then becomes narrowed in,
presenting a sloping overhanging shoulder at each side, in which shoulder there
are a number of openings for admission of combustible gas from a gas flue behind.
From the shoulder upwards the kiln still narrows in to the top where there is a
feeding hole provided with a cover, or there may be several such holes according to
the dimensions of the kiln. At some distance below the feeding holes there are lateral
openings on each side of the kiln leading to a chimney flue. Within the kiln there is
a wedge shaped structure extending some distance up from the bottom, and
presenting on each side a slope corresponding nearly to the slope of the lower
part of the kiln wall. In the narrow portions at the bottom of the kiln there are
lateral openings for admission of air and removal of the burnt material.
central wedge shaped structure may have within its upper part a cavity supplied
with air, and openings therefrom into the body of the kiln. In large kilns there
may be several wedge shaped structures as above described, and when the kiln is
of round or square form the structure may be conical or pyramidal. Each set of
the gas flues and each of the chimney flues is provided with suitable dampers.
The operation, as, for instance, in burning lime, is as follows:-The kiln being
charged and kindled, combustible gas is admitted by the apertures through the
The

page_text: overhanging shoulder at the one side of the kiln, and this gas enters into com-
bustion with air, which ascending from the apertures at the bottom of the kiln is
highly heated by passing through the hot lime already burnt. The flame and
products of combustion strike in an oblique direction upwards and across the body
of limestone above to the apertures leading to the chimney flue on the opposite side
of the kiln which is then open. From time to time the one gas flue and the
chimney flue opposite to it are closed by their dampers, the other gas flue and
chimney flue being opened. The flame and hot products of combustion are thus
for a time directed obliquely upwards crossing the body of limestone, say, from the
right hand side of the kiln to the left hand side, then for a time from the left hand
side to the right hand side, and so on alternately. The limestone fed in at the top
of the kiln becoms dried, heated, and burnt as it descends to the zone of combustion,
and as the lime descends below that zone it becomes cooled by the passage through
it of the air ascending to support the combustion and is from time to time with-
drawn by the lateral openings at the bottom of the kiln. With other material,
such as cement or ore, the operation is similarly conducted. Instead of combustible
gas from a producer, hydrocarbon vapour may be employed as the fuel, or the
spray of hydrocarbon liquid blown in by hot air or superficial steam, or both,
in which latter case suitable nozzles are provided in lieu of the gas apertures above
described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Crosland in the Great Seal Patent Office, on the 26th
October 1881.
EDWARD CROSLAND, of Arnside, near Milnthorpe, in the County of West-
moreland, Civil Engineer. "IMPROVEMENTS IN LIME KILNS, APPLICABLE ALSO
FOR CALCINING CEMENT, ORE, OR OTHER MATERIAL.”
My Invention relates to a construction of kiln in which continuous calcining of
lime, or of cement, ore, or other material is effected by the combustion of gas from
a gas producer, or by hydrocarbon vapour or spray. The kiln which I employ
widens out from the bottom to a certain height and then becomes narrowed in,
presenting a sloping overhanging shoulder at each side, in which shoulder there are
a number of openings for admission of combustible gas from a gas flue behind.
From the shoulder upwards the kiln still narrows in to the top where there is a
feeding hole provided with a cover, or there may be several such holes according
to the dimensions of the kiln. At some distance below the feeding holes there are
lateral openings on each side of the kiln leading to a chimney flue. Within the
kiln there is a wedge shaped structure extending some distance up from the bottom
and presenting on each side a slope corresponding nearly to the slope of the lower
part of the kiln wall. In the narrow portions at the bottom of the kiln there are
lateral openings for admission of air and removal of the burnt material. The
central wedge shaped structure may have within its upper part a cavity supplied
with air, and openings therefrom into the body of the kiln. In large kilns there
may be several wedge shaped structures as above described, and when the kiln is
of round or square form the structure may be conical or pyramidal. Each set of
the gas flues and each of the chimney flues is provided with suitable dampers.
The operation, as, for instance, in burning lime is as follows:-The kiln being
charged and kindled, combustible gas is admitted by the apertures through the
overhanging shoulder at the one side of the kiln, and this gas enters into com-
bustion with air, which ascending from the apertures at the bottom of the kiln is
highly heated by passing through the hot lime already burnt. The flame and
products of combustion strike in an oblique direction upwards and across the body
of limestone above to the apertures leading to the chimney flue on the opposite
side of the kiln which is then open. From time to time the one gas flue and the
chimney flue opposite to it are closed by their dampers, the other gas flue and
chimney flue being opened. The flame and hot products of combustion are thus
for a time directed obliquely upwards crossing the body of limestone, say, from the
right hand side of the kiln to the left hand side, then for a time from the left
hand side to the right hand side, and so on alternately. The limestone fed in at
the top of the kiln becomes dried, heated, and burnt as it descends to the zone of
combustion, and as the lime descends below that zone it becomes cooled by the
passage through it of the air ascending to support the combustion, and is from
time to time withdrawn by the lateral openings at the bottom of the kiln. With
other material, such as cement or ore, the operation is similarly conducted.
Instead of combustible gas from a producer, hydrocarbon vapour may be employed
as the fuel, or the spray of hydrocarbon liquid blown in by hot air or superheated
steam, or both, in which latter case suitable nozzles are provided in lieu of the gas
apertures above described.
In the accompanying Drawings, Figs. 1 and 2 are vertical sections on planes at
right angles to one another of a lime kiln according to my Invention; Fig. 3 is a
sectional plan on Z, Z. From the bottom where there are lateral sloping openings M
for discharge of the burnt lime, the kiln widens out upwards and then is narrowed

page_text: +
by the sloping overhanging shoulder A at each side. In the wall behind this
shoulder are formed the gas flues J having apertures H leading into the body of
the furnace. By these apertures combustible gas supplied from a producer to the
inlet I of the gas flues enters the kiln, and meeting with air rising from the
bottom burns, producing great heat in the body of the material with which the
kiln is charged.
Besides the air entering by the discharge apertures M an
additional supply of air enters or can be forced as a blast through perforations in
a triangular tube L which forms the summit of a wedge shaped structure B formed
at the bottom of the kiln. The gas flues J are provided with valves or dampers Q
and cleaning doors K. At a little distance above the gas apertures H there are a
number of sight holes N by which the heat at different parts of the material can
be ascertained; G, G, are the chimney flues each provided with a damper O by
which the draught can be regulated, so that as determined by inspection through
the sight holes N the current of burning gas and hot products of combustion can
he directed so as to vary the heat in different parts of the material under treatment.
P is the cover of the feeding aperture made tight by a sand joint. The kiln
constructed as shewn in the Drawings is worked, as above described, by opening
for a time one of the gas valves Q and the chimney dampers O on the opposite
side of the kiln, so as to direct the flame and products of combustion obliquely
across the material. The kiln might however be narrowed in at the top to one
central chimney or range of chimnies, thus dispensing with the working of the
dampers O, and such a central chimney might also be used as the feeding aperture
thus dispensing with the cover P.
Having thus described the nature of my Invention and in what manner tho
same is to be performed, I claim,—
-
The herein described construction of lime kiln, applicable also for calcining
cement, ore, or other material, according to which gas from a producer admitted by
lateral apertures in an overhaning shoulder of the kiln burns in the body
of the material, treated along with air rising from below, and the products of
combustion ascend as described through the material above, drying and heating it
as it descends to the zone of combustion.
In witness whereof, I, the said Edward Crosland, have hereunto set my hand
and seal, this Eighteenth day of October, in the year of our Lord One
thousand eight hundred and eighty one.
EDWARD CROSLAND. (L.S.)