IMPROVEMENTS IN THE PRODUCTION OF CARBONIC ACID GAS
Year: 1860

page_text: LETTERS PATENT. to Harrison Blair, of Kearsley Works, Farnworth, in
the County of Lancaster, Manufacturing Chemist, for the Invention of
"IMPROVEMENTS IN THE PRODUCTION OF CARBONIC ACID GAS."
Sealed the 18th July 1860, and dated the 19th January 1860.
PROVISIONAL SPECIFICATION left by the said Harrison Blair at the
Office of the Commissioners of Patents, with his Petition, on the 19th
January 1860.
I, HARRISON BLAIR, of Kearsley Works, Farnworth, in the County of
Lancaster, Manufacturing Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE PRODUCTION OF CARBONIC ACID. GAS," to
be as follows:-
In manufacturing carbonic acid gas, I place carbonate of lime or other
suitable carbonate within a close vessel, which I then heat to redness by any
convenient means, and I also apply the agency of superheated vapor of water,
or other vapors or gases, admitted internally, by which means carbonic acid
is evolved in a state of considerable purity, applicable to various useful
purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Harrison Blair in the Great Seal Patent Office on the
19th July 1860.
-TO-ALL-TO-WHOM-THESE-PRESENTS-SHALL COME, I, HARRISON
BLAIR, of Kearsley Works, Farnworth, in the County of Lancaster, Manu-
facturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of January, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Hor heirs and successors, give and grant unto me,
the said Harrison Blair, Her special licence that I, the said Harrison
Blair, my executors, administrators, and assigns, or such others as I, the
said Harrison Blair, my executors, administrators, 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 Bri-
tain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE PRODUCTION OF CARBONIC ACID GAS," upon the condition,
amongst others, that I, the said Harrison Blair, 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

page_text: the purposes in which caustic lime is generally used, the agents employed for
that purpose being heat and the vapour of water (steam).
The apparatus I use consists of fire-clay retorts or pipes, seven feet long,
and fifteen inches in diameter, open at both ends, to which are adapted cast-
iron mouth pieces, with covers provided with set screws, as those used in the
manufacture of coal gas. Each mouth-piece is also furnished with a two-inch
diameter cast-iron branch; that at one end of the retort, which I will call the
back (as applied to the oven) is for the admission of steam, and that at the
other end or front for the emission of gas and vapour. Three or more of
these retorts may be placed in an oven or furnace, similar to those used in
coal gas works, and heated by coke or coals. The steam, before admission
into the retorts, is superheated, by being caused to pass through iron pipes
embedded in the brickwork between the ovens, and down the brickwork of
the back of the oven to the branch in the mouth-piece (the branches being
on the upper side of the mouth-pieces), the tap for the regulation of the
admission of steam being placed at the front side of oven, to be handy for
the workmen. It is not desirable to heat the steam to redness in cast-iron
pipes, as in that case hydrogen is evolved, which has an injurious action on
the carbonic acid for subsequent use.
I will now describe the mode of operating:-The oven is firstly slowly
heated, in order to avoid fracture of the retorts, and when at a red heat is
charged at the front end with from one and a half to two hundredweight of
limestone, broken to about an inch cube, and the covers secured with slacked
lime, and screwed fast; when at a red heat, steam may be admitted. A half-
inch lap, if the pressure of steam be equal to ten or twelve pounds on the
square inch, will' be sufficient, and carbonic acid gas will be evolved. At the
end of four hours the charge may be shoved towards the back end of the
retort, and a fresh charge introduced. In about four hours more, the first
charge may be drawn at the back, the charge then in the retort shoved back,
and a charge again placed in the front, so that there will be always two charges
being operated upon in the retorts. The gas emitted is mixed with aqueous
vapour, which, if requisite, may be separated by being cooled in condensers
similar to those used in coal gas works for the same purpose.
I have above described a certain arrangement of apparatus which may be
employed for the purpose of carrying out my Invention, and also a certain
method of operating, but I desire it to be understood that I do not limit
myself thereto, as many modifications may be adopted; that which I claim, as
secured to me under the above in part recited Letters Patent, being the

page_text: production of carbonic acid gas for the aforesaid purposes by treating car-
bonate of lime or other suitable carbonate, within a closed vessel and in a
heated state, with the vapour of water.
In witness whereof, I, the said Harrison Blair, have hereunto set my
hand and seal, this Eighteenth day of July, in the year of our Lord
One thousand eight hundred and sixty.
HARRISON BLAIR. (L.S.)