IMPROVEMENTS IN THE MANUFACTURE LETTERS
Year: 1882

page_text: LETTERS PATENT to Alfred Julius Boult of the firm of W. P. Thompson &
Boult Agents for Foreign Patent Solicitors of 323 High Holborn in the
county of Middlesex and 6 Lord Street Liverpool in the county of
Lancaster Engineer for an Invention of "IMPROVEMENTS IN THE MANUFACTURE
LETTERS PATENT to Alfred Julius Boult of the firm of W. P. Thompson &
Boult Agents for Foreign Patent Solicitors of 323 High Holborn in the
county of Middlesex and 6 Lord Street Liverpool in the county of
Lancaster Engineer for an Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF CAUSTIC SODA AND CAUSTIC POTASH AND IN APPARATUS THEREFOR
"
Communicated to him from abroad by Hermann Herberts of the firm of
C. A. Herberts of Barmen, in the German Empire, Chemical Manufacturer.
PROVISIONAL SPECIFICATION left by the said Alfred Julius Boult at the
Office of the Commissioners of Patents on the 27th July 1882.
ALFRED JULIUS BOULT of the firm of W. P. Thompson & Boult Agents for
Foreign Patent Solicitors of 323 High Holborn in the County of Middlesex and
6 Lord Street Liverpool in the County of Lancaster, Engineer "IMPROVEMENTS
IN THE MANUFACTURE OF CAUSTIC SODA AND CAUSTIC POTASH AND IN APPARATUS
THEREFOR [A communication to him from abroad by Hermann Herberts of
the firm of C. A. Herberts of Barmen, in the German Empire, Chemical
Manufacturer]
"
In making sodasalt or carbonate of potassa caustic, so as to produce caustic soda or
caustic potash, it is of advantage to employ closed vessels and steam under pressure
so that the process goes on under a higher pressure than the atmosphere because
then stronger lyes can be made caustic But in this process the difficulty arises
that in drawing off the lyes in order to filter them a considerable proportion is
reconverted into carbonate of potash and soda salt. To meet this difficulty the
filtration must take place under increased pressure also.
The machinery necessary for this purpose consists of a container in which to
the lyes of soda or potash is added the necessary quantity of limestone, The liquid
is drawn from this into a boiler the pipe to which is placed so far above the
bottom of the container that the stones of lime lying on the bottom of the container
cannot pass into the boiler.

page_text: In the boiler there is a mechanical stirrer which mixes the liquid and keeps it in
.continual motion whilst steam is supplied through a pipe from a neighbouring
boiler; a pressure gauge is provided in order that the pressure of the steam may
be regulated. After having been worked by the stirrer the liquid is conducted
through a pipe into the filtering apparatus which is beforehand put under steam
pressure passing on the way over a distributing plate where it spreads itself. The
filter consists of two perforated plates and a steel wire gauze with lime sand
between. Whilst the liquid is passing from the boiler to the filter the pressure in
the latter is kept a little lower than that in the former which may be accomplished
by partly opening a cock. From the filter the prepared lye is conducted to the
usual evaporating apparatus
After the process is finished the steam which is still in the boiler and filter is.
conducted to the container where it heats the water for dissolving the next
charge. The size or form of this apparatus may be varied as required to suit
circumstances

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Julius Boult in the Great Seal Patent Office on the
27th January 1883.
ALFRED JULIUS BOULT of the firm of W. P. Thompson and Boult Agents for
Foreign Patent Solicitors of 323 High Holborn in the county of Middlesex and
6 Lord Street Liverpool in the county of Lancaster, Engineer "IMPROVEMENTS
IN THE MANUFACTURE OF CAUSTIC SODA AND CAUSTIC POTASH, AND IN APPARATUS
THEREFOR." A communication to me from abroad by Hermann Herberts, of
the firm of C. A. Herberts of Barmen in the German Empire, Chemical
Manufacturer.
In making soda salt or carbonate of potassa caustic, so as to produce caustic
soda or caustic potash, it is of advantage to employ closed vessels and steam under
pressure so that the process goes on under a higher pressure than the atmosphere
because then stronger lyes can be made caustic.
But in this process the difficulty arises that in drawing off the lyes in order to
filter them a considerable proportion is reconverted into carbonate of potash and
soda salt. To meet this difficulty the filtration must take place under increased
pressure also
The necessary apparatus consists of a container, marked A in the drawing, in
which the lyes of soda or potash are added to the necessary quantity of limestone;
The liquid is then drawn off into the boiler B through the pipe C. The end of the
pipe C stands so high above the bottom of the reservoir A that the limestone lying
on the bottom cannot pass with the liquid into the boiler B. There is a mechanical
stirrer in the Boiler B as shown which thoroughly mixes the liquid and keeps it in
continual motion whilst steam is supplied through the pipe d from a neighbouring
boiler, the pressure being ascertained by means of the gauge e.
The liquid after having been worked by the stirrer is led through the pipe F
into the filtering apparatus D, which is beforehand put under steam pressure by
means of the pipe p the end of which g discharges upon the plate where the
fluid spreads itself and thence reaches the filter i. The filter consists of the two
perforated plates k and m, the steel wire gauze n n and the limestone sand
between. In conducting the liquid from B into D, the pressure in D is kept a little
lower than in B, which can be accomplished by partly opening the cock O-After
passing through the filter the prepared lye is conducted through the pipe r to the
usual evaporating apparatus. After the process is completed the steam which is
still in B and D is led by pipe q to A where it beats the dissolving water for the
following charge.
The above described operations can be carried out in apparatus of varying
form and size and reasonable modifications in structural detail can of course be
made.
Having now described this invention as communicated to me by my foreign
correspondent I wish it to be understood that what I claim and desire to protect
under the hereinbefore in part recited Letters Patent is ;
First-The filtration of lyes under a pressure higher than that of the atmosphere
substantially as set forth

page_text: Second The combination of apparatus substantially as described and illustrated in
which the filtration of lyes may be accomplished under a pressure higher than
that of the atmosphere
In witness whereof I the said Alfred Julius Boult have hereunto set my
hand and seal this twenty sixth day of January in the Year of Our Lord:
One thousand eight hundred and eighty three
ALFRED J. BOULT (L.S.)