Improvements in the Process and Means for Manufacturing Crystallised Sugar in Refineries.
Year: 1891

page_text: Date of Application, 5th Aug., 1891
Complete Specification Left, 5th May, 1892-Accepted, 11th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Process and Means for Manufacturing
Crystallised Sugar in Refineries.
I, THEODOR DROST, 29 Oberschlesischen Bahnhof, Breslau, Empire of Germany,
Merchant, do hereby declare the nature of this invention to be as follows:-
This invention relates to a new process of working for producing crystal
sugar in sugar refineries, by the employment of filtered refinery syrup for casing
raw sugar.
Crystal sugar has hitherto in refineries been produced from raw sugar essentially
by two processes, ric. by casing by means of steam or by means of cleare, that
is a concentrated solution of finished white sugar. For this purpose the process is
usually as follows
The raw sugar is mixed with low value syrup, run into the centrifugal machine
and then cased either with steam, or with about 40 to 50 per cent. of the above
named solution of finished white sugar, until the crystals are freed from the adherent
syrup by the steam or the casing liquid, and pure almost 100 per cent. sugar or that
of 99 and over polarisation is obtained.
In the steam casing process, by which about 70 to 75 per cent. of pure crystallised
sugar is obtained, it is actually a great drawback, that so considerable a part of the
sugar is dissolved and added to the bye products, whilst the drawback of the cleare
casing process is that a great quantity of finished white sugar must be previously
dissolved to form the casing substance, and that this solution also is added to the
bye products in consequence of the casing, so that already finished white sugar
passes into them.
By this process indeed 10 per cent. more of crystallised sugar is obtained than is
the case of the steam casing process, but at least as much of finished white
sugar, on which all the costs of refining have been incurred is consumed for the
casing liquid, as was dissolved by the steam casing, and is finally added to the
bye products.
To obviate this drawback forms therefore the object of this invention, by which
the syrup produced in refining and used for making lump sugar, loaf sugar, candy etc.
is employed in the peculiar manner hereinafter described.
In refining processes in which lump or loaf sugars, candies etc. are to be produced,
the mode of procedure without exception is to form a saccharine solution of about
50 degrees Balling by dissolving raw sugar in water in so called dissolving pans,
which is then mechanically filtered. The diluted sweetened water is added to
this preliminary filtered solution and the whole is then filtered through spodium.
The juice running from the spodium filter i.e. the refinery syrup, which has
almost always a density of 45 to 48 degrees Balling and in all refineries is
about of equal goodness and concentration, is then boiled down in vacuum into a
solid mass and finally from this, articles fit for consumption are produced in the
usual manner.
In the process forming the object of this invention, the essentially similar refinery
syrup which in the current processes of refining is present in all sugar refineries,
having generally from about 90 to 93 degrees of purity, is employed for the
production of crystallised sugar, and the process is conducted in such a way that
first a dissolving of sugar in the centrifugal machine is avoided, and also secondly
for the production of the casing fluid no already finished white sugar on which the
whole costs of refining have been incurred is employed.
For this purpose, the refinery syrup which at its density of 45 to 48 degrees
Balling would still dissolve sugar in the centrifugal machine, is, by this invention,
boiled down in a special vacuum evaporating apparatus to a specific gravity of

page_text: about 1·15 to 1.325 or about 57 to 66 degrees Balling, so that it is no longer in a
condition to dissolve raw sugar crystals in the centrifugal machine, but yet in itself
no crystallisation has taken place. It is preferable for concentrating the refinery
syrup to use a special vacuum apparatus, but the casing liquid can be also taken
from the actual vacuum boiling pan in use, at a suitable time i.e., as soon as the
suitable degree of concentration is attained.
With such filtered refinery syrup concentrated in a vacuum apparatus to about
57 degrees to 66 degrees Balling this process is preferably carried out in the
following way.
Raw sugar is mixed with low value syrup and is jigged in the centrifugal machine
of which the space between the case and drum and therewith the mass of sugar
is preferably warmed, until the sugar is freed as far as possible from the raw syrup
adhering thereto. The sugar has then a degree of purity about 98 per cent.
whilst the quotient of purity of the syrup still adhering to the crystals attains
about 69 to 71.
Then this sugar is cased in the centrifugal, preferably with continued heating
with the refinery syrup concentrated in the above described manner of about
1.15 to 1325 specific gravity. For this, in order to sufficiently remove the syrup
of a purity quotient of about 69-71 still adhering to the crystals, it is necessary
to use 8-10 per cent. of the weight of the mass of sugar which is to be cased of
casing liquid and, as the casing liquid has a degree of purity of about 90 to 93
whilst loss of crystal sugar through being dissolved in the centrifugal is avoided, a
crystallised sugar of at least 99-5 polarisation is obtained as a finished universally
marketable product.
It is preferable in casing in the centrifugal to take care that the temperature of
the refinery syrup used for casing be not higher than that in the space of the casing
vessel and that the remainder of the syrup left in the cased sugar, be as far
as possible completely centrifugalled out of the sugar, preferably whilst the latter
is kept warmed until it contains only one per cent. moisture. The syrup running
away from the casing which is impoverished two or three degrees of purity, say to
about 90, is either conveyed to the filter or the vacuum pan and in this way a cycle
of operations is completed.
The advantages of this process are essentially as follows:-
No steam casing is required for producing crystal sugar in refining by which a
considerable quantity of the mass of crystallised sugar contained in the centrifugal
was dissolved and carried off in the bye products.
Further it is no longer necessary in producing crystallised sugar in refining, to
dissolve finished white sugar as the dearest material for this purpose for the
production of casing substance and thus finally to carry off the same in the bye
products.
On the contrary the purifying liquid for raw sugar used in this invention is the
cheapest, because it is produced of itself in the process of refining i.e., is always
present, and further this process causes no loss of sugar.
Dated this 4th day of August 1891.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Process and Means for Manufacturing
Crystallised Sugar in Refineries.
I, THEODOR DROST, 29, Oberschlesischen Bahnhof, Breslau, Empire of 50
Germany, Merchant, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
This invention relates to a new process of working for producing crystal sugar in

page_text: sugar renneries, by the employment of Intered remuery syrup for Casing
sugar.
Crystal sugar has hitherto been produced in refineries from raw sugar essentially
by two processes, namely, by casing by means of steam or by means of cleare, that
is a concentrated solution of finished white sugar.
For this purpose, the process is usually as follows:-
The raw sugar is mixed with low value syrup, run into the centrifugal machine
and then cased either with steam, or with about 40 to 50 per cent. of the above-
named solution of finished white sugar, until the crystals are freed from the
adherent syrup by the steam or the casing liquid, and pure almost 100 per cent. sugar
or that of 99 and over polarisation is obtained.
In the steam casing process, by which about 70 to 75 per cent. of pure crystallised
sugar is obtained, it is actually a great drawback that so considerable a part of the
sugar is dissolved and added to the bye products, whilst the drawback of the cleare
casing process is that a great quantity of finished white sugar must be previously
dissolved to form the casing substance, and that this solution also is added to the
bye products in consequence of the casing, so that already finished white sugar
passes into them.
By this process indeed 10 per cent. more of crystallised sugar is obtained than is
the case with the steam casing process, but at least as much of finished white
sugar, on which all the costs of refining have been incurred, is consumed for the
casing liquid as was dissolved by the steam casing, and is finally added to the bye
products.
To obviate this drawback forms therefore the object of this invention, by which
the syrup produced in refining and used for making lump sugar, loaf sugar,
candy, etcetera, is employed in the peculiar manner hereinafter described.
In refining processes in which lump or loaf sugars, candies, etcetera, are to be
produced, the mode of procedure without exception is to form a saccharine solution
of about 50 degrees Balling by dissolving raw sugar in water in so called dissolving
pans, which is then mechanically filtered. The diluted sweetened water is added
to this preliminary filtered solution, and the whole is then filtered through spodium
(bone black).
The juice running from the spodium filter, that is the refinery syrup, which has
almost always a density of 45 to 48 degrees Balling and in all refineries is about
of equal goodness and concentration, is then boiled down in vacuum into a solid
mass and finally, from this, articles fit for consumption are produced in the usual
manner.
In the process forming the object of this invention, the essentially similar
refinery syrup, which in the current processes of refining is present in all sugar
refineries, having generally from about 90 to 93 degrees of purity, is suitably
employed for the production of crystallised sugar, and the process is conducted in
such a way that, first, a dissolving of sugar in the centrifugal machine is avoided,
and also, secondly, for the production of the casing fluid, no already finished
white sugar on which the whole costs of refining have been incurred is
employed.
For this purpose, the refinery syrup, which, at its density of 45 to 48 degrees
Balling, would still dissolve sugar in the centrifugal machine, is, by this invention,
boiled down in a specially reserved vacuum evaporating apparatus (any suitable form
of apparatus will do but it is best not to use such for any other purpose) to a
specific gravity of about 1.15 to 1.325 or about 57 to 66 degrees Balling, so that it
is no longer in a condition to dissolve raw sugar crystals in the centrifugal machine,
but yet in itself no crystallisation has taken place. It is preferable, for concen-
trating the refinery syrup, to use a special vacuum apparatus, but the casing liquid
can be also taken from the actual vacuum boiling pan in use, at a suitable time,
that is, as soon as the suitable degree of concentration is attained.
With such filtered refinery syrup concentrated in a vacuum apparatus to about

page_text: 57 degrees to 66 degrees Balling, this process is preferably carried out in the
following way—
Raw sugar is mixed with low value syrup and is jigged in the centrifugal
machine, of which the space between the case and drum and therewith the mass of
sugar is preferably warmed, until the sugar is freed as far as possible from the raw
syrup adhering thereto. The sugar has then a degree of purity about 98 per cent.,
whilst the quotient of purity of the syrup still adhering to the crystals attains
about 69 to 71.
This sugar is then cased in the centrifugal machine, preferably with continued
heating, with the refinery syrup, concentrated in the above described manner, of
about 115 to 1325 specific gravity. For this, in order to sufficiently remove the
syrup of a purity quotient of about 69 to 71 still adhering to the crystals, it is
necessary to use 8 to 10 per cent. of the weight of the mass of sugar which is to be
cased of casing liquid, and, as the casing liquid has a degree of purity of about 90
to 93, whilst loss of crystal sugar through being dissolved in the centrifugal
machine is avoided, a crystallised sugar of at least 99.5 polarisation is obtained
as a finished, universally marketable, product.
It is preferable, in casing in the centrifugal machine, to take care that the
temperature of the refinery syrup used for casing be not higher than that in the
space of the casing vessel and that the remainder of the syrup left in the cased
sugar be, as far as possible, completely centrifugalled out of the sugar, preferably
whilst the latter is kept warmed, until it contains only 1 per cent. moisture.
syrup running away from the casing, which is impoverished two or three degrees
of purity, say to about 90, is either conveyed to the filter or the vacuum pan and
in this way a cycle of operations is completed.
The advantages of this process are essentially as follows:-
The
No steam casing is required for producing crystal sugar in refining, by which a
considerable quantity of the mass of crystallised sugar contained in the centrifugal
machine was dissolved and carried off in the bye products.
Further, it is no longer necessary, in producing crystallised sugar in refining, to
dissolve finished white sugar, as the dearest material for this purpose, for the
production of casing substance and thus, finally, to carry off the same in the bye
products.
On the contrary, the purifying liquid for raw sugar used in this invention is the
cheapest, because it is produced of itself in the process of refining, that is, is always
present; and, further, this process causes no loss of sugar.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improvements in the process for manufacturing crystallised sugar in
refineries, which consist essentially in the employment therefor of filtered refinery
syrup, which is preferably boiled down in the vacuum steaming down apparatus
(to the specific gravity of about 1.15 to 1325) so far that, at the degree of con-
centration and the temperature at which it is employed, it neither deposits crystals
nor dissolves any of the sugar which is to be cased suitably, together with the
heating of this latter in order to facilitate the expulsion of the casing material, all
substantially as hereinbefore set forth.
2. A casing substance suitable for manufacturing crystallised sugar in refineries,
produced and treated as hereinbefore described, which consists of filtered
refinery syrup which is boiled down in a vacuum apparatus to about 1.15 to 1.325
specific gravity.
Doted this 4th day of M- 1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.