IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC ALKALIES, AND IN APPARATUS THEREFOR
Year: 1879

page_text: LETTERS PATENT to George Isaac James Wells, of the Firm of Wells and
Galloway, of Widnes, in the County of Lancaster, Alkali Manufacturers,
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC
ALKALIES, AND IN APPARATUS THEREFOR.”
Sealed the 16th December 1879, and dated the 22nd September 1879.
PROVISIONAL SPECIFICATION left by the said George Isaac James
Wells at the Office of the Commissioners of Patents on the 22nd September
1879.
GEORGE ISAAC JAMES WELLS, of the Firm of Wells and Galloway, of Widnes,.
in the County of Lancaster, Alkali Manufacturers. "IMPROVEMENTS IN THE
MANUFACTURE OF CAUSTIC ALKALIES, AND IN APPARATUS THEREFOR."
My Invention has for its object the simplifying, cheapening, and perfecting of
the present method of obtaining caustic alkali from its carbonate by means
of lime.
The usual plan is to dilute the liquid carbonate to about fifteen Twaddle, and run
it into a tank or trough open or closed, when it is heated by means of steam to
ebullition and well stirred in contact with caustic lime. The lime combines with
the carbonic acid, leaving the soda or potash, as the case may be, in solution in the
caustic state.
This heating with steam at considerable cost has been assumed to be necessary
to perfect the decompositions, the theory being that the hotter the solution becomes
the more rapidly decomposition takes place. I find however that it is not necessary
to use this high temperature, and that the operation may be performed at far
higher densities than usual by working under pressure without extraneous heat,
especially if the agitation of the mixture be more perfectly effected than is possible
by arrangements now in use.
My Invention therefore consists, first, in doing away with steaming, hitherto
thought necessary, and secondly, in an improved apparatus for effecting the
process.
My improved apparatus consists in placing in a closed chamber or boiler a
series of vanes, like screw-propellers, on a central shaft and alternating with

page_text: these attached to the boiler shell rigid vanes pointing in the opposite direction,
consequently when the shaft and arms are rotated a very violent agitation
results.
At one or two points a break occurs in the agitators, and here I insert the
stationary cage filled with lime from a hopper and cone valve above, milk of lime
can also be added. The shaft carrying the agitators passes from end to end of the
boiler in the same manner as in the ordinary troughs, and is turned by an engine
at one end.
The process consists in filling the lime cages with the proper proportion of lime;
the soda solution is then introduced so as completely to fill the vessel, and then by
means of a force pump driving in liquid till a pressure as heavy as the boiler can
safely sustain is attained.
The agitating machinery is then set in motion and kept going till the conversion
is accomplished. The caustic solution is then separated from the lime mud in the
ordinary manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Isaac James Wells in the Great Seal Patent Office on the
22nd March 1880.
GEORGE ISAAC JAMES WELLS, of the Firm of Wells and Galloway, of Widnes,
in the County of Lancaster, Alkali Manufacturers. "IMPROVEMENTS IN
MANUFACTURE OF CAUSTIC ALKALIES, AND IN APPARATUS THEREFOR."
THE
My Invention has for its object the simplifying, cheapening, and perfecting
of the present method of obtaining caustic alkali from its carbonate by means
of lime.
The usual plan is to dilute the liquid carbonate to about fifteen Twaddle, and run
it into a tank or trough, when it is heated by means of steam to ebullition, and well
stirred in contact with caustic lime.
The lime combines with the carbonic acid, leaving the soda or potash, as the case
may be, in solution in the caustic state.
This heating with steam at considerable cost has been assumed to be necessary
to perfect the decomposition, the theory being that the hotter the solution becomes
the more rapidly decomposition takes place. I find however that it is not necessary
to use this high temperature, and that the operation may be performed at far
higher densities than usual by working under pressure without extraneous heat,
especially if the agitation of the mixture be more perfectly effected than is possible
by arrangements now in use.
The Drawings annexed represent sectional elevations of my apparatus as at
present employed by me, taken longitudinally and transversely at the cage. A is a
closed chamber or boiler, in which are placed a series of vanes B, B, like screw
propellers on a central shaft C, and alternating with these attached to the boiler
shell rigid vanes D, D, pointing in the opposite direction, consequently when the shaft
and arms are rotated a very violent agitation results. At one or two points a break
occurs in the agitators, and here I insert the stationary cage E, E, filled with lime
from a hopper F and cone valve G above, milk of lime can also be added or sub-
stituted. The shaft carrying the agitators passes from end to end of the boiler in
the same manner as in the ordinary troughs, and is turned by an engine H at one
end; I, I, are bearings carried by cross pieces attached to the shell.
.
The process consists in filling the lime cages with the proper proportion of lime,
introducing the soda solution so as completely to fill the vessel, the lime is dissolved
in the usual manner, and then by means of a force pump cold or hot water, or the
carbonate liquid is driven in till a pressure as heavy as the boiler can safely sustain
is attained. The agitating machinery is then set in motion and kept going till the
conversion is accomplished. The caustic solution is then separated from the lime
mud in the ordinary manner.
Having now described my Invention, and the best mode known to me of carrying
it into effect, I wish it to be understood that I make no claim for causticizing with
the liquor kept at or below the temperature of the atmosphere, as the liquor is
always heated during the slacking and dissolving of the lime, but that what
I believe to be new and desire to protect by the herein before in part recited Letters
Patent is,
The above described process of manufacturing caustic soda or caustic potash by
violently agitating the carbonate liquor with lime under mechanical or hydraulic
pressure, and without the agency while the pressure is applied of other heat or

page_text: steam than that which the materials operated upon already contain or generate
during the operation.
In witness whereof, I, the said George Isaac James Wells, have hereunto
set my hand and seal, this Twentieth day of March, in the year of our Lord
One thousand eight hundred and eighty.
Witness,
W. P. THOMPSON,
Patent Agent,
6, Lord Street,
Liverpool, &
323, High Holborn,
London, W.C.
GEORGE I. J. WELLS. (L.S.)

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