IMPROVEMENTS IN MAKING GRANULATED CRYSTALLINE CARBONATE OF SODA, AND IN APPARATUS THEREFOR to be as follows:
Year: 1884

page_text: I, JAMES MACTEAR, of 16 Burnbank Gardens, Glasgow, in the County of Lanark,
North Britain, Manufacturing Chemist, do hereby declare the nature of my said
invention for "IMPROVEMENTS IN MAKING GRANULATED CRYSTALLINE CARBONATE
OF SODA, AND IN APPARATUS THEREFOR to be as follows:-
"
My said Invention relates to the production or manufacture of carbonate of soda
(sometimes known as sal soda or soda crystals) in a granulated crystalline form.
The carbonate of soda is much more convenient for general use when in a granular
or minutely-crystalline condition, than when in large hard masses or crystals as
commonly supplied; also when produced in the granular form it is obtainable of
superior quality by very convenient and economical processes which I have devised.
One such process forms the subject of Letters Patent No 1714 of 1875, granted to
me; and my present Invention consists in modifying and improving that process
and the apparatus employed in carrying it out.
My improved apparatus consists of a long shallow trough the bottom of which is
cooled by water and which receives the solution of carbonate of soda at one end
the granulated crystals being discharged at the other end. A number of scrapers
work in the trough, being fixed to a frame to which a longitudinal reciprocating
motion is given by cranks on a rotating shaft. These scrapers move in contact or
nearly so with the bottom of the trough when moving towards the discharge end
but are lifted during their return movements; and the extent of their movement
is greater than the space between two scrapers so that at each stroke each scraper
acts on the granular soda pushed forward during the previous stroke by the scraper
next behind it, and in this way the granular soda is gradually moved along the
trough and finally discharged.
In using the apparatus the warm solution of carbonate of soda is poured by
a pipe into one end of the trough, and is supplied at a rate sufficient to maintain a
depth of about half an inch at the inlet end of the trough. The cold water passing
through the space beneath the trough (being by preference supplied at the discharge
end, and led off at the other end) causes rapid crystallisation, and the continually
repeated movements of the scrapers not only prevent the formation of large crystals
or masses but also at the same time move the crystallised soda towards the
discharge end of the trough. The granulated soda is discharged into a tank or
nli....מ

page_text: receptacle from which it is transferred to a hydroextractor for the purpose of
separating adherent liquid.*
In preparing the solution of carbonate of soda for the purpose of being brought
into a granulated crystalline form with the aid of apparatus of the kind herein-
before described, instead, of treating the "vat" or "red" liquor in the manner
described in my earlier specification hereinbefore referred to, I convert it by known
processes into "soda ash" preferably of high strength and then dissolve it in a
sufficient quantity of water and after settling pass the solution thus obtained
through the apparatus. Or the solution of carbonate of soda may be obtained from
soda ash or alkali made by the process known as the Ammonia-Soda process; and,
especially when the ash or alkali used is of high strength, in which case there will
be little or no residuary mother liquor and no weak alkali need be produced as is
unavoidable with the usual processes for manufacturing ordinary sal soda.
I, JAMES MACTEAR, of 16 Burnbank Gardens, Glasgow, in the County of Lanark,
North Britain, Manufacturing Chemist, do hereby declare the nature of my said
invention for "IMPROVEMENTS IN MAKING GRANULATED CRYSTALLINE CARBONATE
OF SODA, AND IN APPARATUS THEREFOR" 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 :-
:―
My said Invention relates to the production or manufacture of carbonate of soda
(sometimes known as sal soda or soda crystals) in a granulated. crystalline form.
The carbonate of soda is much more convenient for general use when in a granular
or minutely-crystalline condition, than when in large hard masses or crystals as
commonly supplied; also when produced in the granular form it is obtainable of
superior quality by very convenient and economical processes which I have devised.
One such process forms the subject of Letters Patent No 1714 of 1875, granted to
me; and my présent Invention consists in modifying and improving that process
and the apparatus employed in carrying it out.
My improved apparatus consists of a long shallow trough the bottom of which is
cooled by water and which receives the solution of carbonate of soda at one end
the granulated, crystals being discharged at the other end. A number of scrapers
work in the trough, being fixed to a frame to which a longitudinal reciprocating
""

page_text: motion is given by cranks on a rotating shaft. These scrapers move in contact or
nearly so with the bottom of the trough when moving towards the discharge end
but are lifted during their return' movements; and the extent of their movement is
greater than the space between two scrapers so that at each stroke each scraper acts
on the granular soda pushed forward during the previous stroke by the scraper
next behind it, and in this way the granular soda is gradually moved along the
trough and finally discharged.
The apparatus is shown in the accompanying drawings, figure, 1, being a plan
with parts broken away or removed, and figure, 2, being a corresponding side
elevation. Figure, 3, is an enlarged transverse vertical section of the trough; and
figure, 4, is an enlarged view of part of the mechanism for lifting the scrapers.
In these drawings the same reference numerals are used to mark the samne or like
parts wherever they are repeated.
Upon two longitudinal beams, 5, transverse boards, 6, are laid to form a platform
for supporting the trough and apparatus. On this platform there are fixed two
longitudinal wooden bars or planks, 7, on which is placed an iron plate, 8, to form
the bottom of the trough. The space beneath the plate, 8, and between the
planks, 7, forms the space, 9, for the cooling water and sheet lead is laid on the
bottom of this space and upon the inner sides and tops of the planks, 7, to make
those parts watertight. The water space, 9, is furnished with partition strips, 10,
(see right-hand side of figure, 1,) arranged with openings alternately at the opposite
sides to make the current of cooling water take a tortuous course on its way from
one end of the trough to the other. The sides of the trough are formed by angle-
iron frames, 11. The scrapers, 12, are vertical plates formed with angled flanges
by which they are fixed to the under sides of transverse iron frames, 13, and these
frames, 13, are fixed to two longitudinal frames, 14, the frames, 13, and, 14, being
of I or double-channel section, and the combination being rendered rigid by diagonal
ties, 15. The scraper frame, consisting of the parts just described, is supported on
rollers, 16, carried by the lower and nearly horizontal arms, 17, of bellcrank levers
centered on brackets or stools, 18, fixed down upon the platform, 6, the rollers, 16,
being entered into the outer channel of the longitudinal frames, 14. The bell-
cranks are formed with upper nearly vertical arms, 19, which are jointed to rods, 20,
extending from one end of the trough to the other, the bellcranks at the discharge
end being jointed to a crossbar, 21, which is connected by a rod, 22, to a lever, 23.
The lever, 23, is acted on as shown in figure, 4, by a cam, 24, on a rotating
shaft, 25; and this same shaft has on its ends cranks, 26, for imparting the longi-
tudinal motion to the scraper frame to the end of which the cranks are connected
by rods, 27. The shaft, 25, is driven from a steam engine or other motor through
any suitable gearing, and the cranks, 26, and the cam, 24, are so placed relatively
to each, as that when the scraper frame is moving towards the discharge end of the
trough the bottom edges of the scrapers, 12, move almost in contact with the
bottom plate, 8, of the trough; whilst during the return movement the cam causes
the bellcranks, 17, 19, to keep the scraper frame raised. At the ends the bottom
of the trough is slightly raised to retain uncrystallised liquid, the part being by
preference curved to correspond to the path of the edge of the end scraper when it
is being raised from its lowest position.
In using the apparatus the warm solution of carbonate of soda is poured by
a pipe, 28, into one end of the trough, and is supplied at a rate sufficient to main-
tain a depth of about half an inch at the inlet end of the trough. The cold water
passing through the space, 9, beneath the trough, (being by preference supplied at
the discharge end, and led off at the other end) causes rapid crystallisation, and the
continually repeated movements of the scrapers not only prevent the formation of
large crystals or masses, but also at the same time move the crystallised soda
towards the discharge end of the trough. The granulated soda is discharged into
a tank or receptacle, 29, from which it is transferred to a hydroextractor for the
purpose of separating adherent liquid.
'

page_text: In preparing the solution of carbonate of soda for the purpose of being brought
into a granulated crystalline form with the aid of apparatus of the kind herein-
before described, instead of treating the "vat" or "red" liquor in the manner
described in my earlier specification herein before referred to. I convert it by
known processes into "soda ash" preferably of high strength, and then dissolve it
in a sufficient quantity of water and after settling pass the solution thus obtained
through the apparatus. My Invention is also advantageously applicable for
obtaining the granulated crystalline carbonate of soda from soda ash or alkali made
by the process known as the ammonia-soda process and especially when the ash or
alkali used is of high strength, in which case there will be little or no residuary
mother liquor and no weak alkali need be produced as is unavoidable with the
usual processes for manufacturing ordinary sal soda.
Having now particularly described and ascertained the nature of my, said
Invention and in what manner the same is to be performed I declare that what
I claim is
1-The hereinbefore-described process of making granulated crystalline carbonate
of soda by dissolving soda ash of suitable strength in a sufficient quantity of water,
and subjecting it to the combined actions of cooling and scraping or agitation
substantially as described.
2-The combination of parts for cooling and scraping or agitating a solution of
carbonate of soda to obtain granulated crystals, and consisting of a long shallow
trough having a passage for cooling water beneath it, together with a number of
scrapers fixed to a frame which receives longitudinal movements from a rotating
shaft and which is lifted during its return movements by bellcránks operated on by
a rotating cam substantially as described.
1 1
1
11002
EDMUND HUNT,
Applicant's Agent.