IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA
Year: 1870

page_text: LETTERS PATENT to Edward Thomas Hughes, of the Firm of Hughes
and Son, Patent Agents, 123, Chancery Lane, London, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA."
-A communication from abroad by William Helbig, of Koestritz,
Prussia.
Sealed the 31st December 1870, and dated the 5th July 1870.
PROVISIONAL SPECIFICATION left by the said Edward Thomas Hughes
at the Office of the Commissioners of Patents, with his Petition,
on the 5th July 1870.
I, EDWARD THOMAS HUGHES, of the Firm of Hughes and Son,
Patent Agents, 123, Chancery Lane, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CAUSTIC SODA," a communication to me from abroad by William Helbig,
of Koestritz, Prussia (to be as follows):-
The greater part of caustic soda is generally obtained from red mother
liquor (caustic lie), which red mother liquor and also the caustic lie
procured from the raw lie by caustic lie contain considerable quantities
of combinations of sulphide of sodium, & for procuring a marketable
product it is necessary that these combinations of sulphur should be
removed.

page_text: Hitherto these removals have been procured by means of saltpetre, but
I entirely dispense with its use, & my Invention consists in manufacturing
caustic soda in the following manner:-The red caustic lie is evaporated
in boilers of cast iron which are heated on the outsides, so that the lie
is thickened and the combinations of oxygen are decomposed by the
development of ammonia. When the foaming ceases the fireing is
increased in order to make the mass red hot, which makes it thinner, and
then the boiler is covered with a metal cover having in the centre a
small chimney and beyond the centre an opening to receive an iron tube
reaching to near the bottom of the interior of the boiler, and through
this tube a current of air is introduced into the melted mass by means
of an air pump. The oxidation of the sulphur combinations immediately
commences, and is controlled by proofs taken at different times, the
proofs or samples being tested by iodine, & the blowing in of air is
continued until all the sulphur is oxidized. The fire is removed and the
register or damper closed whilst the contents of the boiler are red hot,
and the contents are permitted to clear up for a few hours, after which
the caustic soda, now ready for use, is taken out, and this process proceeds
surely and regularly without any danger if the air is not blown in with
too great force.
For the introduction of air I use a strong metal pipe bent at right
angles and suspended by a chain passed over a roller, and the part of
the tube in the interior of the boiler has at the bottom a plate with a
few perforations, the other part of the tube being connected by gutta
percha or india-rubber piping to the air pump.
I may mention that the air pipe is to be kept in the boiler no longer
than the air is being introduced in order to prevent stoppage, but if any
stoppage should take place it is only necessary to knock or tap the sides
of the pipe to loosen the obstruction.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Thomas Hughes in the Great Seal Patent
Office on the 4th January 1871.
.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents, 123,
Chancery Lane, London, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of July, in the year of our
Lord One thousand eight hundred and seventy, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Edward Thomas Hughes, Her special licence that
I, the said Edward Thomas Hughes, my executors, administrators, and
assigns, or such others as I, the said Edward Thomas Hughes, 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 Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF CAUSTIC SODA,” a communication to me from abroad by
William Helbig, of Koestritz, Prussia, upon the condition (amongst
others) that I, the said Edward Thomas Hughes, my exccutors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, 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 Scal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Edward Thomas Hughes, 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 thereof, that is to say :—
The greater part of caustic soda is generally obtained from red mother
liquor (caustic lie), which red mother liquor and also the caustic lic
procured from the raw lic by caustic lime contain considerable quantities
of combinations of sulphide of sodium, and for procuring a marketable
product it is necessary that these combinations of sulphur should be
removed.
Hitherto these removals have been procured by means of saltpetre,
but I entirely dispense with its use, and my Invention consists in manu-
facturing caustic soda in the following manner :-The red caustic lic is
evaporated in boilers of cast iron which are heated on the outsides, so
that the lic is thickened and the combinations of oxygen are decom-
posed by the development of ammonia. When the foaming ceases the
firing is increased in order to make the mass red hot, which makes it

page_text: thinner, and then the boiler is covered with a metal cover having in the
centre a small chimney, and beyond the centre an opening to receive an
iron tube reaching to near the bottom of the interior of the boiler, and
through this tube a current of air is introduced into the melted mass by
means of an air pump. The oxidation of the sulphur combinations
immediately commences, and is controlled by proofs taken at different
times, the proofs or samples being tested by iodine, and the blowing in
of air is continued until all the sulphur is oxidized. The fire is removed
and the register or damper closed whilst the contents of the boiler are
red hot, and the contents are permitted to clear up for a few hours,
after which the caustic soda, now ready for use, is taken out, and the
process proceeds surely and regularly without any danger if the air is
not blown in with two great force.
For the introduction of air I use a strong metal pipe bent at right
angles and suspended by a chain passed over a roller, and the part of
the tube in the interior of the boiler has at the bottom a plate with a
few perforations, the other part of the tube being connected by gutta
percha or india-rubber piping to the air
pump.
I may mention that the air pipe is to be kept in the boiler no longer
than the air is being introduced in order to prevent stoppage, but if any
stoppage should take place it is only necessary to knock or tap the sides
of the pipe to loosen the obstruction.
Having now described the nature and particulars of the said Invention
as communicated to me, I claim the improvements in the manufacture
of caustic soda, as hercin set forth.
In witness whereof, I, the said Edward Thomas Hughes, have here-
unto set my hand and seal, this Fourth day of January, in the
year of our Lord One thousand eight hundred and seventy-one.
ET HUGHES