IMPROVEMENTS IN PURIFYING SUGAR
Year: 1876

page_text: LETTERS PATENT to Alexander Scott, junior, of the Firm of Alexander Scott
and Sons, of Greenock, in the County of Renfrew, North Britain, Sugar
Refiners, and Thomas Robertson Ogilvie, of the same Place, Analytical Chemist,
for the Invention of "IMPROVEMENTS IN PURIFYING SUGAR."
Sealed the 1st September 1870, and dated the 11th March 1876.
PROVISIONAL SPECIFICATION left by the said Alexander Scott and Thomas
Ogilvie at the Office of the Commissioners of Patents on the 11th March 1876.
ALEXANDER SCOTT, junior, of the Firm of Alexander Scott and Sons, of Greenock,
in the County of Renfrew, North Britain, Sugar Refiners, and THOMAS ROBERTSON
OGILVIE, of the same Place, Analytical Chemist. "IMPROVEMENTS IN PURIFYING
SUGAR."
This Invention has for its object to separate saline and other impuritics from
beetroot sugar and cane sugar in an improved and simplified manner, and it con-
sists in mixing the sugar in its raw or impure state with water or with a saccharine
solution, and in subjecting the mixture as soon as made to the action of a centri-
fugal drainer, such as is commonly used in sugar refineries.
The water or saccharine solution is by preference used as cold as it can con-
veniently be made, and whilst the proportion of it to be mixed with the sugar will
depend on the quality and condition of the sugar, about one part by weight for
every seven parts of beetroot sugar, or for every ten parts of cane sugar, is a
suitable proportion for average raw or impure sugars.
The mixture is by preference made in a separate vessel fitted with any convenient
kind of agitator, which agitator is by preference kept in motion whilst the water or
saccharine solution is being added to the sugar.
The mixture is operated upon by the centrifugal machine as speedily as possible,
and whilst the liquid is being thrown off a quantity of water or saccharine solution
(about equal to that first added, or rather less in the case of beetroot sugar) is to be
applied to it in the centrifugal machine to effect a further separation of impurities.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Alexander Scott and Thomas Robertson Ogilvie in the Great Scal Patent
Office on the 7th September 1876.
ALEXANDER SCOTT, junior, of the Firm of Alexander Scott and Sons, of Greenock,
in the County of Renfrew, North Britain, Sugar Refiners, and THOMAS ROBERTSON
OGILVIE, of the same Place, Analytical Chemist. "IMPROVEMENTS IN PURIFYING
SUGAR."
Our said Invention has for its object to separate saline and other impurities from
beetroot sugar and cane sugar in an improved and simplified manner, and it consists in
mixing the sugar in its raw or impure state with water or with a saccharine solution,
and in subjecting the mixture as soon as made to the action of a centrifugal drainer
such as is commonly used in sugar refinerics. And in order that our said Invention
and the manner of performing the same may be properly understood we proceed to
particularly describe the manner in which we prefer to carry it out in practice, with
the view of obtaining the best results.
The water or saccharine solution to be mixed with the sugar may be cold or hot,
but is by preference used as cold as it can conveniently be made, the proportion of
it to be mixed with the sugar depending upon the quality and condition of the
sugar. For 100 parts by weight of beetroot sugar, from 10 to 15 parts of water
should be used, or say 12 parts water for an average raw or impure beetroot sugar.
For 100 parts of cane sugar from 7 to 15 parts of water should be used, or say
parts water for an average raw or impure cane sugar. When a saccharine solution,
consisting of a solution of sugar, mado specially, or of syrup more or less diluted, or
of the liquor known as "char water," is used instead of water for mixing, a larger
proportion should be employed, according to the specific gravity of the solution.
For example, when using "char water" of 12 to 15 degrees Beaumé, an increase of 2
to 5 parts should be made on the proportions herein-before specified.
The mixture is by preference made in a separate vessel fitted with any kind of
mechanical agitator or mixer, and the agitator or mixer is by preference kept in
motion whilst the water or saccharine solution is being added to the sugar, and until
the mass is well mixed.
The mixture is operated upon by the centrifugal machine as soon as possible after
its formation, and whilst the liquid is being thrown off, that is, immediately on the
machine getting into full motion. A quantity of water or saccharine solution is to
be applied to the sugar in the centrifugal machine to effect a further separation of
impurities. The quantity of water or saccharine solution to be applied in this way
will depend on the amount of impurities remaining in the sugar, and on the degree
of purification desired. From 2 to 10 parts of water or saccharine solution may
be applied for every 100 parts of sugar, the necessary degree of purification in
working sugar of average quality being attainable by using 2 parts for beetroot
sugar, and 3 to 4 parts for cane sugar. The centrifugal machine is kept in motion
until liquid ceases to be thrown off. The sugar as removed from the centrifugal
machine will be found to be to a great extent freed from saline and organic impuri-
ties, and, if desired, may then be transferred to the "blow-up," and be put through
the usual process of refining. In this way a higher class of refined sugar will be
obtained than that got from sugar not subjected to the preliminary purifying process
herein-before described.
The liquid or syrup got from the centrifugal machines will yield a crop of sugar
on being boiled and "jellied," and the operations may be repeated until sugar ceases
to crystallise, when only molasses will remain. The sugar obtained in this way
may be purified in the same manner as the original raw or impure sugar,
Having thus particularly described our said invention, and the manner of per-
forming the same, we have to state that we do not restrict ourselves to the precise
details herein-before described or referred to, but that what we believe to be novel
and original, and claim as the Invention secured to us by the herein-before in part

page_text: recited Letters Patent, is, the mixing of sugar in its raw or impure state with
water or with a saccharine solution, and subjecting the mixture to the action of a
centrifugal drainer, substantially as and for the purposes herein-before described.
In witness whereof, we, the said Alexander Scott, junior, and Thomas Robertson
Ogilvie, have hereunto set our hands and seals, this Fifth day of September,
in the year of our Lord One thousand eight hundred and seventy-six.
ALEXANDER SCOTT, JUN".
(L.S.)
THOMAS ROBERTSON OGILVIE. (Ls.)