IMPROVEMENTS IN THE MANUFACTURE OF CEMENT
Year: 1862

page_text: LETTERS PATENT to Henry Young Darracott Scott, of Brompton
Barracks, near Chatham, in the County of Kent, Captain in the Royal
Engineers, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
CEMENT."
Sealed the 8th July 1862, and dated the 15th March 1862.
PROVISIONAL SPECIFICATION left by the said Henry Young Darracott
Scott at the Office of the Commissioners of Patents, with his Petition,
on the 15th March 1862.
I, HENRY YOUNG DARRACOTT SCOTT, of Brompton Barracks, near Chatham,
in the County of Kent, Captain in the Royal Engineers, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CEMENT," to be as follows:-
My Invention of improvements in the manufacture of cement consists in
subjecting lime in the state of powder to the action of sulphurous acid gas, and.
oxydising influences. The lime may be either pure or hydraulic, either quick
or partially slaked. The pulverised condition of the lime greatly facilitates the
action of the gas, and enables methods of impregnation to be employed in the
preparation of cement, which are impracticable when the lime is operated

page_text: upon in lumps, as has hitherto been practised in the preparation of the
cement known in the market as Scott's cement.
By the improved methods above referred to cement can be prepared from
lime with crenter cortainty and economy than heretofore
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Young Darracott Scott in the Great Seal Patent
Office on the 15th September 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
YOUNG DARRACOTT SCOTT, of Brompton Barracks, near Chatham, in the
County of Kent, Captain in the Royal Engineers, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of March, in the year of our Lord One
thousand eight hundred and sixty-two, in-the-twenty-fifth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Henry Young Darracott Scott, Her special license, that I, the said Henry
Young Darracott Scott, my executors, administrators, and assigns, or such
others as I, the said Henry Young Darracott Scott, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF CEMENT," upon the
condition (amongst others) that I, the said Henry Young, Darracott Scott,
by an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in. what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Young Darracott Scott, do
hereby declare the nature of my said Invention, and in what manner the
same is to be performed; to be particularly described. and ascertained in and
by the following statement (that is to say):-
The object of this Invention is to manufacture the patent cement known.in
the market as "Scott's cement," in a more certain and economical manner
than heretofore. To attain this end I submit quick lime in a powdered state
(or the lime may be partially slaked. and still answer the purpose) to the

page_text: action of sulphurous acid gas in the presence of some efficient oxydizing
agent, and thus ensure a rapid and thorough conversion of the lime into
cement.
In carrying out my Invention I sift the pulverized lime by the aid of a
revolving drum made with meshes (or equivalent means) through a flue or
shaft built of or lined with fire-bricks, and kept at a full red heat by the flame
of an adjacent reverberatory furnace, which I cause to play into the shaft, and
down which I also pass a continuous stream of sulphurous acid gas. The
flame and sulphurous acid gas are made to turn down the shaft by the draft of
a chimney stack, which gradually splays outwards towards the top, so as to
moderate the draft (which it is. necessary to keep up over the fire-bridge)
before the heated air. finally escapes into the atmosphere. By thus moderating
the draft the finer particles of cement that pass onward with the ascending
gases are not carried out of the chimney, but deposited on its sides. and fall
back.
.
:
The flame in passing down the shaft heats the powdered lime in its fall
sufficiently to enable the lime to absorb the sulphurous acid gas which passes
down with it.
. For the, production of the sulphurous acid gas I provide a large iron, vessel
of sulphur, and by means of a small fire underneath the vessel I cause the
sulphur to burn with sufficient rapidity to give off a large volume of gas. I
employ one pound of sulphur, more or less, for every eighty pounds of lime,
and, sometimes I substitute for sulphur in whole or in part iron pyrites, brassy
coal, and other substances which can be made readily and economically to give
up the sulphur they may contain. The sulphurous acid gas generated by the
burning sulphur I conduct into the reverberatory furnace before mentioned
through the floor of the ash-pit of that furnace, a louvre board arrangement of
ash-pit floor being adopted, to, permit of the gaseous product passing through
while the cinders which fall from the bars of the furnace are retained on the
floor: When the gas has entered the ash-pit it makes its way into the fire-place
between the fire-bars, and thoroughly intermingles with the furnace flames.
If iron pyrites or other like substances be used, however, for the production of
the sulphurous acid, they may be mingled with the fuel of the furnace. In
that case the peculiar ash-pit arrangement above described will be unnecessary.
In order to give the sulphurous acid, gas a better opportunity of acting upon
the lime feather-edged fire tiles are placed across the shaft, having their broad
surfaces at a steep inclination (about seventy degrees). The operation of these
surfaces, will be to delay the descent of lime, and thereby increase its tempera-
ture. The lime powder as it makes its way through the shaft takes up a

page_text: small per-centage of the sulphurous acid, and under the influence of the high
temperature and atmospheric air which should be present rapidly passes to
that condition which is necessary to the production of the cement. If the fire
is properly managed (the fresh fuel being always added in a manner to:coke
it when at a distance from the fire-bridge, and the area over the fire-bridge
being proportioned to the combustion) additional air will be required to
perfect the consumption of the smoke, and to supply the oxydising agency
requisite for the reconversion of any sulphurous acid which may have been
decomposed and to complete the process. This can be supplied by perforation's
through the wrought-iron casing, which should enclose the sieve already
referred to. The cement as it falls to the bottom of the shaft may be removed
by an endless chain of iron buckets working over tension pulleys, or by other
suitable machinery, and when removed it should be spread out to cool, or its
cooling may be hastened by suitable mechanical arrangements. Successful
results may be obtained by the use of shafts from one foot square in plan to
four feet by two feet and upwards, with a drop for the lime of from four to
ten feet, so long as the furnace attached to it is of sufficient size to make the
lime red hot, and the draft is properly regulated. Four feet by two feet with
a vertical drop of eight feet are good working dimensions for the shaft, the
flame playing across the shorter dimension.
I consider the above to be the best mode of carrying out my Invention, but
other means may be employed for impregnating the powdered lime with the
required substances. For instance, instead of making the lime powder red hot
the lime powder may be introduced into a cylinder or other chamber fitted
with the means of constantly carrying it to its upper part, and allowing it to
drop across the cylinder. While the cylinder is rotating vapour of water and
sulphurous acid are to be passed into it, and the compound resulting from this
operation is to be exposed to the oxydizing influence derived either from
nitrous acid fumes and atmospheric air or heat and atmospheric air; or again,
instead of the above I may pass sulphurous acid gas, atmospheric air, and
vapour of water over spongy platinum or other oxydizing agent contained in a
tube into a cylinder such as that above described.
.
Though, however, I have employed these and similar means in a somewhat
varied form to produce the cement, I do not recommend their adoption,
considering the mode which I have first and most fully described, to be
the most economical and certain and best method of manufacturing the
cement.
Having now set forth the nature of my Invention of "Improvements in
the Manufacture of Cement," and explained the manner of carrying the

page_text: same into effect, I wish it to be understood that under the above in part
recited Letters Patent, I claim subjecting lime in the pulverized state to the
action of sulphurous acid gas and an oxydizing agency, in the manner and for
the purpose above described.
In witness whereof, I, the said Henry Young Darracott Scott, have
hereunto set my hand and seal, the Thirteenth day of September,
in the year of our Lord One thousand eight hundred and sixty-two.
HENRY Y. D. SCOTT. (L.s.)