Improvements in the Treatment of Saccharine Solutions which have been Boiled to the Granular State.
Year: 1891

page_text: Date of Application, 19th May, 1891
Complete Specification Left, 17th Feb., 1892-Accepted, 19th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Saccharine Solutions which have
been Boiled to the Granular State.
A communication from abroad by THE MASCHINENFABRIK GREVENBROICH, of
Grevenbroich, Prussia, German Empire, Manufacturers.
1, JOHN CLAYTON MEWBURN of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents, do hereby declare the nature
of this invention to be as follows:-
When the first raw sugar product or the corresponding after product of the
refineries which has been subjected to granulation by boiling is passed through the
centrifugal machine, the syrup passes through the centrifugal sieve with the finest
crystals and residues arising from the mashing and this syrup is now used for boiling
down inferior products.
This syrup may be used according to the present invention in such a way that
the syrup and the fine powder of crystals may be run into the vacuum along with
the next lot of liquid after this latter has been subjected to the preparatory
boiling.
The vacuum syrup is thereby thinned or diluted and the syrup added becomes
warmed, so that both again dissolve the fine crystals present in the sugar-liquor,
and those which were added with the syrup. The coarsely crystallized mass so
obtained is run into barrels or completely cooled and crystallized in one of the
known refrigerating crystallizers provided with a stirrer.
The next treatment in the centrifugal machine proceeds as before; the syrup
and the meal of crystals, which has once more been formed, are added to the
sugar-liquor at the end of the next boiling and so on.
By this means the syrup will gradually accumulate to such an extent that a part
of it has to be withdrawn from the granulating process. This is effected after the
powder has well subsided; then the upper portion of the syrup which is free from
crystals is drawn off from the granulating vessel, and the lower portion is again
drawn into the vacuum.
When this operation has been performed several times the liquors may gradually
be boiled down to a somewhat thicker consistency, for the products of crystallization
of this process are considerably coarser than is usually the case, because the fine
crystals are for the most part dissolved, and thus the greater part of the after-
products can be obtained in one operation.
The process of crystallizing the liquors arising from granulation as well as the
after-products by refrigeration is much simpler, if after the granulation thick juice
or clear liquor, such as is subjected to granulation, is added in considerable
quantities, so that the smallest crystals (the secondary crystallization which takes
place towards the end of the granulation) are dissolved and the diluted liquor
then crystallized either by being left at rest, or preferably as mentioned above, in
continual motion.
Dated this 19th day of Mar 1891.

page_text: COMPLETE SPECIFICATION.
Improvements in the Treatment of Saccharine Solutions which have
been Boiled to the Granular State.
A communication from abroad by THE MASCHINENFABRIK GREVENBROICH, of
Grevenbroich, Prussia, German Empire, Manufacturers.
I, JOHN CLAYTON MEWBURN of 55 and 56 Chancery Lane in the County of
Middlesex, Chartered Patent Agent, 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 :—
When the first raw sugar product or the corresponding after product of the
refineries, which has been subjected to granulation by boiling leaves the vacuum, it
appears as a more or less seniliquid liquor, which is generally allowed to entirely
solidify in vats or vessels and it is afterwards made liquid in mashing machines
with the addition of syrup. If the liquor is closely examined firstly immediately
after running out of the vacuum and secondly while running from the mashing
machine, it will be seen, that within the original crystals (formed in the vacuum)
which are large and well developed, there has been formed an extensive after
crystallization; the separating of sugar in the vats or vessels from the existing
syrup during cooling of the liquor has not enlarged the existing grain by growth,
but has merely formed new and very small crystals, which will again be dissolved
if the syrup is not concentrated for mashing. This fine grain, even if not dissolved
during mashing, will be almost entirely lost while the first product is being
obtained because the small crystals will pass with the syrup during the centrifugal
operation through the perforations of the centrifugal sieve and will be regained
only in the ejected syrup as a second product. That part of the small crystals,
which in this way is lost in the first product, will decrease the quality of the latter.
It is especially this characteristic of the cooled down liquor-to which hitherto
not enough attention has been paid in the further treatment which accounts for the
fact, that particularly the first products do not give such profits or results, as should
be expected according to the density or intensity of the boiling.
It is the object of the present invention to increase the profits or returns or
extraction, especially in the first crystallizing process of the sugar and this invention
has more particularly in view the prevention as far as possible of any after
crystallization on the one hand and on the other hand instead of adding or incorporat-
ing the small crystals which are nevertheless formed and which escape through the
perforations of the centrifugal machine, to the next inferior product, to add or
incorporate such crystals to a product of equal or still better quality and to thus
obtain them in the form of well developed crystals.
While thus adding the liquid product of the centrifugal action to one boiling,
ready boiled in the vacuum, the syrup containing the small crystals delivers a part
of its crystallizible sugar to the well developed crystals of the more valuable
product. This syrup also first dissolves the fine grain, which may have been formed
in the vacuum and afterwards allows the sugar thus taken up to grow in addition
to and with the well developed crystals.
By drawing the syrup into the ready boiled mass and by the subsequent after
boiling, a liquor is obtained which, although all obtainable sugar is contained in
it in the solid form of coarse crystals, is still fluid and easily drawn off.
This invention therefore is a process of continuous working of liquor boiled to
the granular state consisting in this, that the syrup ejected from the centrifugal
drum without dilution, together with the crystal meal or fine powder of crystals of
a preceding boiling of the same or of an inferior product is drawn into the
vacuum after the drawing in of the thick juice or liquor and after the gradually
more dense, boiling down to the granular state and that, if too large a bulk or
quantity of the run off syrup has accumulated, a part of such syrup, after the

page_text: crystal meal has become deposited or subsided, is drawn on from the vesser FOT
separate working, while the deposited or subsided meal is used or worked in the
continuous working process.
In carrying out the process it may be stated as an example that the first product
of raw sugar is densely boiled down to grain, afterwards 10 to 20 per cent. of syrup
is drawn into the vacuum and the mass is then again reboiled. The drawn in
syrup has to be heated to a somewhat higher degree than the mass in the vacuum,
so that the syrup after having been drawn in may boil up at once and thereby
thoroughly mix. If for instance the mass is 160 to 162° F., the syrup to be drawn
in should be about 167 to 178° F. After the thus completed boiling mass has
been cooled down to about 100° F. in a cooling down crystallizer with agitator
(after about 12 to 18 hours)-the same is submitted to the centrifugal operation
undiluted and the syrup run off is used again for the after treatment of the next
boiling of first products.
For commencing this process the following procedure is recommended.
The first boiling or mass is lightly boiled so that the liquor after thoroughly
cooling down may still contain up to 30 per cent. of syrup. This liquor is drawn
off into a large cooling down crystallizer with agitator in order to cool under
permanent agitation. Then the liquor is submitted to the centrifugal operation
undiluted so that about 27 per cent. of syrup with about 5 per cent. of the smallest
crystals are ejected by the centrifugal action, while a result or extraction of about
68 per cent. is obtained.
This is no doubt less, than in the ordinary process, but this loss will be made up
in the next centrifugal operation; for the ejected syrup will be drawn together
with the 5 per cent. crystals into the vacuum at the next boiling, after the
crystallization has been finished by boiling it down to the granular form. The
boiling inass will thereby become somewhat diluted, the crystals of the heated
syrup as well as the smallest crystals of the boiling mass being dissolved-in order
to grow on or enlarge the existing grain partly during the after boiling in the
vacuum, partly in the cooling down crystallizer with agitator. The liquor thus
obtained after complete cooling down will contain about twice the bulk of
syrup
the first boiling, and therefore notwithstanding its being boiled more densely-is
still more liquid and casier to be agitated.
of
If the formation of grain should be the same in the second crystallization as in
the first, there would again be ejected by centrifugal action 5 per cent. of the fine
crystals, but as the 5 per cent. of the crystal meal from the first boiling are
dissolved and separated as coarse crystals, these are gained in the second centrifugal
operation, that is about 73 per cent. of the nondiluted liquor, and thus the ordinary
good result or extraction is reached or obtained. In fact the granulation in the
second crystallization is superior to the first, because while adding the syrup at
the completion or end of the vacuum crystallization the smaller crystals of the
boiling mass are dissolved and give up their sugar to the coarse grain in the after
boiling, so that the loss of solid sugar is not so large in the centrifugal operation
as in the beginning and the result or extract is more advantageous than in the
ordinary process.
In the third boiling (and still more in the subsequent boiling processes) the
concentration of liquor may still be more increased (because more syrup for
addition is at disposal) and boiling may be extended to such a density, as would
lead in ordinary process to the so called dry boiling, so that a considerable part of
that sugar, which has been in a dissolved state in the run off syrup, crystallizes
with or enlarges the coarse crystals and thus the above described process will
prove to be far more advantageous than the processes which are now generally in
The increase in the concentration may take place in the vacuum or in the
entirely closed cooling down crystallizer, which in this instance may be connected
to the air pump.
use.
Meanwhile the syrup will gradually accumulate to such an extent, that part of
same must be excluded from the process. This is done by allowing such part to

page_text: settle, so that the crystal meal will deposit or fall to the bottom. Then part of
the upper syrup is allowed to flow off and to be afterwards boiled as a second
product, while the lower syrup with the crystal meal is drawn into the vacuum to
inix with the first product.
If it is not so much desired to have a large result or extraction as to gain a
superior quality, it is not necessary to keep on increasing the concentration of the
boilings and the process may go on as above stated, but it is to be borne in mind
that shortly before stopping the supply of the thick juice or liquor to be bciled,
the grain boiling crystallization is to be stopped, and after strong or dense boiling
the rest of the thick juice or clear liquor is drawn in at once, so that the mass of
liquor is diluted. The thus diluted mass of liquor in which the finest crystals
will dissolve is then poured into the above mentioned apparatus viz. the cooling
down crystallizers, in order to crystallize while in motion.
It is not a matter of necessity to use for the process described the cooling down
crystallizers but the cooling down may take place in vats; however in this latter
case the mass of liquor must be mashed before being submitted to the centrifugal
process. But it is preferred to work with cooling down.crystallizers having
agitators. In these the mass is cooled down while agitated, the mass not becoming
solid but remaining liquid, so that it may be conducted out of the cooling down
crystallizer directly into the centrifugal apparatus.
It is obvious that in the first place all manual labour between the vacuum and
the centrifugal apparatus is dispensed with. Secondly the mass can be cooled
down to the desired degree by artificial cooling so that it is rendered more
capable of forming crystals, without forming crystal meal, that is, very small
crystals, in consequence of irregular refrigeration. Thirdly no lumps of crystals
grown together are formed, which would require a mashing action and which would
retain the syrup to a greater extent, than the isolated products obtained by
crystallization in motion.
Having now particularly described and ascertained the nature of the said
invention as communicated to me and in what manner the same is to be performed,
I declare that what I claim is :-
1. A process for crystallizing granulated saccharine liquors by refrigeration as
set forth; that is to say :-
a. The syrup separated in the centrifugal machine from the liquor arising
from the previous boiling is run into the vacuum at the end of the granu-
lation.
b. The mixture so obtained is cooled and crystallized either in barrels, vessels
or vats or in coolers provided with stirrers or agitators.
c. The surplus syrup after the subsidence of its fine crystals or crystal meal is
drawn off or excluded from the process.
2. A process for crystallizing by refrigeration saccharine liquors that have been
granulated, as set forth, that is to say :-
a. The boiled liquor after the granulation is finished, is diluted with thick
juice such as is subjected to granulation or with clear boiled liquor in the
vacuum, and
:
h. Then treated as in 16 and 1 c.
Dated this 17th day of February 1892.