Means of Aqueous, Alcoholic or other Saccharine Solutions..
Year: 1887

page_text: Means of Aqueous, Alcoholic, or other Saccharine Solutions..
I, CARL STEFFEN of No. 2 Heugasse in the City of Vienna, Austria, Engineer, do
hereby declare the nature of my invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to an improved process for systematically lixiviating or
washing raw sugar by means of a solution of sugar in water, alcohol, glycerine,
acetic acid or their or its equivalents, whereby the operation is continuously carried
out with the same lixiviating fluid.
This lixiviating fluid (which consists of more than 12 portions, divided according
to their specific gravity and which are composed of sugar solutions of regularly
increasing purity ranging from a molasses like syrup up to a pure sugar solution) is
so led through the raw sugar to be purified that the molasses like syrup will drive
off the molasses from the sugar crystals during the passage of the lixiviating fluid
through the raw sugar, and the last portion of the said molasses like syrup is driven
off by a fresh pure solution of sugar whilst the sugar in the said pure sugar solution
will adhere to the washed raw sugar crystals. The lixiviating fluid is repeatedly
employed in like manner for lixiviating raw sugar.
In lixiviating raw sugar by means of an aqueous solution of sugar the most
concentrated lixiviating fluid passes slowly through the layers of sugar in consequence
of the viscous nature of the said lixiviating fluid. In consequence hereof the dis-
advantage ensues that the following more pure and consequently more fluid lixiviating
fluid must also be caused to flow slowly through the mass of raw sugar. The
lixiviating fluid would thus remain too long in contact with the raw sugar mass and
the consequent super saturation of the lixiviating fluid would cause the sugar to
crystallise out, and decrease the penetrating power of the fluid through the raw sugar
to be washed.
For removing this disadvantage I employ two means, either each for itself or in
combination with each other.

page_text: A. In connection with the lixiviating apparatus I arrange special vessels (cellular
vessels) in such manner that the cells of such vessels receive the lixiviating fluid in
desired succession in such quantity that a separation of the same according to the
specific gravity of the fluid is attained so that the lixiviating fluid after leaving the
vessels containing the cells operates on the sugar to be lixiviated in the same
succession as if the same on passing off from the raw sugar mass is led direct onto
the quantity of raw sugar which is next to be treated according to my lixiviating
process.
By means of this arrangement I secure the advantage that the lixiviating fluids
will always pass through the granular mass of sugar with the greatest speed corre-
sponding to the reduced specific gravity of the said lixiviating fluid.
B. An appropriate quantity of water is added to the lixiviating fluid during the
lixiviating stage and before the same is led onto a fresh quantity of raw sugar.
In carrying my process into effect I employ open lixiviating vessels A with
perforated or sieve bottoms a into which the raw sugar is introduced. Beneath the
sieve bottom I arrange a collecting space for the lixiviating fluid which has passed
through the sugar mass which said fluid is drawn off by means of a pump or vacuum
into the vessel through the tube B, (Fig. 1).
The distribution of the lixiviating fluid in the compartments or cells of the vessels C
and the abstraction of the same from the said cells or compartments of the aforenamed
vessels C can be effected by hand or automatically.
The connection between the vessels C and the lixiviating vessels A containing the
granular mass of sugar can be arranged in various ways without departing from the
nature of my invention, for instance,
1. A lixiviating battery with more than two lixiviating vessels (Fig. 1) whereby
each lixiviating vessel A corresponds with a vessel C containing compartments or
cells which vessel C is of such size that it can receive the fluid from about six cells
or compartments of the lixiviating vessel. The operation of my system is as
follows:-
The lixiviating fluids which pass through the granular mass of sugar in the
lixiviating vessel flow successively in the order of their respective specific gravities
into the vessel C, fill the separate cells and pass from the same in like succession
into the following lixiviating vessel.
As the flowing speed of the washing or lixiviating fluid at the forward end is the
least, it is a matter of course that the greatest accumulation of the fluid will be in
the subdivided vessel corresponding with the washing or lixiviating vessel which has
last been put in operation, whilst few or hardly any cells or compartments of the
last vessel will be filled with the part of the lixiviating fluid first put into operation.
The accumulation in the compartments of the intermediate vessels decreases towards
the vessel longest under treatment.
2. A lixiviating battery consisting of two washing or lixiviating vessels (Fig. 2).
In this case a vessel with compartiments or cells is also arranged for each lixiviating
vessel, but the former must have at least double the capacity of the lixiviating vessel
and contain more than 12 cells or compartments in pre-determined succession. The
raw sugar contents of the vessel A being saturated with syrup of the highest con-
centration the washing fluid having combined with the molasses adhering to the raw
sugar passes into the empty vessel (". The last and purest lixiviating fluid which
saturates the mass of sugar in the lixiviating vessel A' is then supplanted by a pure
solution of sugar into the still empty cells of the vessel from whence the same
passes on to the sugar crystals in the vessel A in corresponding succession. When
the supplanting of the lixiviating fluid in the vessel A¹ has been completed the
purified crystalline mass is removed and the said vessel filled with a fresh quantity of
raw sugar onto which the fluid accumulated in the corresponding compartment
vessel is led in the aforesaid successive order to carry out a fresh lixiviating
operation.
3. A lixiviating battery consisting of two lixiviating vessels with one compartment
vessel Figure 3.

page_text: The capacity of the compartment or subdivided vessel must be at least two and a
half times greater than the capacity of the lixiviating vessels and must contain more
than twelve cells or compartments in predetermined succession. The operation is
carried out in such manner that the contents of the lixiviating vessel A is saturated
with the lixiviating fluid of greatest concentration so as to drive off the molasses
adhering to the raw sugar crystals. The lixiviating fluid passing off from the vessel A
is forced into the first (empty) compartments of the subdivided vessel C³ in desired
succession whilst the contents of the last compartments of the said vessel C³ are
successively led into the lixiviating vessel A' and then the last washing or lixiviating
fluid remaining in the aforesaid vessel A¹ supplanted by a pure solution of sugar and
introduced into the last compartments or cells of the vessel C³.
4. A lixiviating battery with one lixiviating vessel and one compartment vessel or
vessel divided into cells (Figure 4.)
The capacity of the compartment or subdivided vessel must in this case as in that
shown in Figure 3 be at least two and a half times greater than the capacity of the
lixiviating vessel and must be subdivided into more than twelve compartments.
The operation is carried out in such manner that the washing or lixiviating vessel A*
which is filled with raw sugar is treated with the contents of the first compartment
of the compartment vessel C, i.e., the most concentrated fluid, and then successively
with the contents of the other compartments whilst the lixiviating fluid from the
vessel A' after passing through the raw sugar and carrying with it the molasses from
the said raw sugar is again led into the compartment vessel C in the former succession
in order to be employed for treating a fresh quantity of raw sugar. In this case the
sanie cells or compartments always receive the same fluid and the last part of the
lixiviating fluid is supplanted by a solution of pure sugar into the last cells of
the vessel C*.
As low temperatures and a large percentage of moisture in the raw sugar will
have the tendency to retard the operation (in the former case very viscid, badly
flowing syrup will adhere to the sugar and reduce the temperature of the lixiviating
fluid thus preventing the same from flowing freely through the raw sugar mass) it is
of decided advantage that, in cold weather, devices be applied for warming the raw
sugar up to a temperature preferably over 10 degrees Centigrade. For this purpose
the raw sugar is either placed in a room or apparatus provided with suitable heating
devices when the said raw sugar is warmed or warmed and dried before the same is
placed in the washing or lixiviating vessel; or, dried warm air is applied beneath the
sieve bottom of the lixiviating vessel so that the same will penetrate through the
mass of raw sugar before the lixiviating fluid is allowed to flow onto the same.
Although I have described these two manners of getting over the difficulty it will
be evident to those versed in the art of refining or purifying sugar that other devices
can be employed and that both the raw sugar and the lixiviating fluid can be warmed
either before or during the operation or operations without departing from the nature
of my said invention.
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. In a process for the systematic lixiviation of raw sugar by means of more or
less pure solutions of sugar in water, alcohol, glycerine or acetic acid the arrangement
application and combination of subdivided vessels, or vessels provided with cells or
compartments for receiving the lixiviating fluid, (which passes through the mass of
raw sugar
in the lixiviating vessel or vessels with varying speed and might otherwise
cause the irregular or improper operation of the washing or lixiviating process,) into
separate cells or compartments according to the predetermined succession and the
increasing or decreasing specific gravity of the fluid, substantially as described in the
foregoing specification.
2. The addition of water to the lixiviating fluid for preventing the crystallisation
of the same, substantially as described in the foregoing specification.
3. The application and employment of the process claimed in claim 1, substantially

page_text: as described in the foregoing specification under the headings 1, 2, 3, 4, and in the
combination as represented by the accompanying drawings.
4. In a process for purifying raw sugar, warming the said raw sugar before
lixiviation to a temperature above 10 degrees Centigrade, substantially as described
in the foregoing specification.
5. In a process for purifying raw sugar, the drying of the wet kinds of raw sugar,
substantially as described in the foregoing specification.
6. In a process for treating raw sugar the introduction of warm air beneath the
sieve bottom of the lixiviating vessel after the same has been filled with raw sugar
for the purpose of warming and drying the raw sugar before the lixiviating operation
commences, substantially as described in the foregoing specification.
C. STEFFEN.
Per W. H. Beck,
115, Cannon Street, London, E.C.,
Agent.