Improvements in the Crystallization of Saccharine and other Solutions.
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 Crystallization of Saccharine and other
Solutions.
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:-
Although it has hitherto been the custom to effect the crystallization of solutions
which have been evaporated by hent to a syrupy consistency only with the greatest
possible tranquility and absence of disturbance of the mass, it is far more
advantageous to subject them to a slow and regular motion; in this way crystalliza-
tion is induced in the solutions in such a manner that every particle comes in contact
with crystals either thrown in or already formed, and the constituents which it is
desired to separate out by cooling grow round these.
The result is that the formation of too many, and consequently small grains of
crystal, is thereby prevented; and further that the crystals forined from or présent
in the liquor grow and subsequently separate out inore easily from the mother
liquor. By this method, too, even solutions of low value will deposit crystallizing
substance on the grains of crystals present.
The invention consists in imparting regular motion to saturated crystallizing
solutions with simultaneous regulation of temperature according to the varying
amount of still uncrystallized substance contained in the solutions; the solution
being brought in contact with ready developed crystals, or with a mass of crystals.
In effecting crystallization by the new process, it is necessary in order to avoid
the formation of crystal grains or small crystals, to first bring the solution to such
a temperature that it neither crystallizes nor is capable of dissolving any more
substance, that is to say one must work at a temperature (or only a trifle under it)
corresponding to the saturated solution. Having succeeded in doing this, well-
developed crystals or a mass of crystals from a previous operation are brought in
contact with the solution, and the liquid is allowed to cool whilst being subjected
to constant niotion. It is further necessary that the crystals or mass of crystals
used should previously have been brought to the temperature of the solution, other-
wise the saturated solution before coming into contact with the crystals or matter
intended to excite crystallization must be rapidy overheated or cooled down to such
an extent that after contact the mixture may arrive, by exchange of heat, at the
temperature approximating to that of saturated solution."
The following may be taken as an example of the way in which the operation is
carried out according to the new process.
The ready prepared, well-developed crystals or mass of crystals are placed in a
tank having a perforated false bottom; beneath this is a tube or channel, and' there
is another tube or channel above the mass of crystals.
The crystals or mass of crystals are brought to a temperature corresponding to
the point of saturation of the solution by means of a jacket enveloping the tank.
The saturated solution which is to be crystallized is now introduced through the
lower tube or channel, care being taken to drive out all the air from between the
crystals; the solution passes through the tank and through the crystals placed in it
and flows off through the upper tube, the process going on continuously. During
this uninterrupted circulation, cooling air or water is caused to flow through the
jacket in order to effect a slow cooling of the solution. Whether only one tank be
worked in one apparatus or several tanks under similar conditions, the jacket can

page_text: be extended so as to regulate the temperature of the whole, or the temperature of
the whole room may be modified to suit ; further instead of the jacket, pipes or
other hollow bodies can be inserted under the perforated bottom.
It is also practicable to combine a series of tanks in such a way that the solutions
which are to be crystallized out flow through one tank after another, leaving the
last one to a great extent or entirely spent. It is necessary during the process to
see that a steady and regular motion is maintained, and the greatest care should be
taken to keep both the solutions and masses of crystals at the necessary temperature,
that is to say the temperature which corresponds to the quantity of dry substance.
that is substance that has not yet crystallized out, contained in the solutions. In
the mode of operation cited I can also proceed in such a manner that crystals
capable of powerfully exciting crystallization can be formed from richer solutions,
these latter being gradually replaced by poorer liquors in order to enable these
also to give up the substance which it is desired to crystallize from them.
To this end it is specially recommended to combine several tanks together into
one battery analogous to that used for diffusions.
The motions of the solutions as above explained can again be supplemented by
stirring-machinery in the tanks or can be entirely replaced thereby. The applica-
tion of stirring-machinery not only effects the necessary circulation of the solution,
but further the crystals are continually occupying new positions so that the channels
between them continually retain a uniform size for the passage of the liquid, and
the formation of nests or groups of crystals is avoided. The stirrers can work
either horizontally or vertically according to the shape and length of the
crystallizing vessels. These latter, too, can also be kept in motion, by rotation
for example. Instead of the slow cooling by air or water, the action of a vacuum
can be combined with the process hereinbefore described, and in this case even heat
may be applied and rapid working is possible; by working under a vacuum the
motion in the mass of crystals is still further increased..
Dated this 19th day of May 1891
Improvements in the Crystallization of Saccharine and other
Solutions.
A communication from abroad by the MASCHINENFABRIK GREVENBROICH, of
Grevenbroich, Prussia, German Empire, Manufacturers.
[JOHN CLAYTON MEWBURN of 55 and 56 Chancery Lane in the County of
Middlesex, Chartered Patent Agent, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
Although it has hitherto been the custom to effect the crystallization of solutions
which have been evaporated by heat to a syrupy consistency only with the greatest
possible tranquility and absence of disturbance of the mass, it is far more
advantageous to subject them to a slow and regular motion; in this way crystalliza-
tion is induced in the solutions in such a manner that every particle comes in contact
with crystals either thrown in or already formed, and the constituents which it is
desired to separate out by cooling grow round these.
The result is that the formation of too many, and consequently small grains of
crystal, is thereby prevented, and further that the crystals formed from or present
in the liquor grow and subsequently separate out more easily from the mother
liquor. By this method, too, even solutions of low value will deposit crystallizing
substance on the grains of crystals present.
The invention consists in imparting regular motion to saturated crystallizing
solutions with simultaneous regulation of temperature according to the varying

page_text: amount of still uncrystallized substance contained in the solutions, the solution
being brought in contact with ready developed crystals, or with a mass of crystals.
In effecting crystallization by the new process, it is necessary in order to avoid
the formation of crystal grains or small crystals, to first bring the solution to such
a temperature that it neither crystallizes nor is capable of dissolving any more.
substance, that is to say, one must work at a temperature (or only a trifle under it)
corresponding to the saturated solution. Having succeeded in doing this, well-
developed crystals, or a mass of crystals from a previous operation, are brought in
contact with the solution, and the liquid is allowed to cool whilst being subjected
to constant motion. It is further necessary that the crystals or mass of crystals
used should previously have been brought to the temperature of the solution, other-
wise the saturated solution before coming into contact with the crystals or matter
intended to excite crystallization must be rapidly overheated or cooled down to
such an extent that after contact the mixture may arrive, by exchange of heat, at
the temperature approximating to that of saturated solution."
The following may be taken as an example of the way in which the operation is
carried out according to the new process.
:.
The ready-prepared well-developed crystals or mass of crystals are placed in a
tank such as shown at Figure 1 of the annexed drawings, having a perforated
false bottom; beneath this is a tube or channel and there is another tube or channel
above the mass of crystals.
The crystals or mass of crystals are brought to a temperature corresponding to
the point of saturation of the solution by means of a jacket enveloping the tank.
The saturated solution which is to be crystallized is now introduced through the
lower tube or channel, care being taken to drive out all the air from between the
crystals, the solution passes through the tank and through the crystals placed in
it and flows off through the upper tube, the process going on continuously.
During this uninterrupted circulation, cooling air or water is caused to flow through
the jacket in order to effect a slow cooling of the solution. Whether only one tank
be worked in one apparatus or several tanks under similar conditions, the jacket
can be extended so as to regulate the temperature of the whole, or the temperature
of the whole room may be modified to suit ; further instead of the jacket, pipes or
other hollow bodies can be inserted under the perforated bottom.
It is also practicable, as shown in Figure 2, to combine a series of tanks in such
a way that the solutions which are to be crystallized out flow through one tank
after another leaving the last one to a great extent or entirely spent. It is necessary
during the process to see that a steady and regular motion is maintained and the
greatest care should be taken to keep both the solutions and masses of crystals at
the necessary temperature, that is to say the temperature which corresponds to the
quantity of dry substance, that is substance that has not yet crystallized out
contained in the solutions. In the mode of operation cited I can also proceed in
such a manner that crystals capable of powerfully exciting crystallization can be
formed from richer solutions, these latter being gradually replaced by poorer
liquors in order to enable these also to give up the substance which it is desired to
crystallize from them.
To this end it is specially recommended to combine several tanks together into
one battery analogous to that used for diffusions.
The motions of the solutions as above explained can again be supplemented by
stirring machinery in the tanks or can be entirely replaced thereby. The applica-
tion of stirring machinery not only effects the necessary circulation of the solution
but further the crystals are continually occupying new positions so that the channels.
between them continually retain a uniform size for the passage of the liquid, and
the formation of nests or groups of crystals is avoided. The stirrers can work
either horizontally or vertically according to the shape and length of the
crystallizing vessels. These latter, too, can also be kept in motion, by rotation
for example. Instead of the slow cooling by air or water, the action of a vacuum
can be combined with the process herein before described, and in this case even heat

page_text: may be applied and rapid working is possible; by working, under a vacuum the
motion in the mass of crystals is still further increased'.
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. For the production of well-developed crystals and' the avoiding of secondary
formation of fine grains, the movement of saturated solutions which it is desired
to crystallize with simultaneous regulation of the temperature according to the
varying quantity of dry substance contained therein, substantially as set forth.
2. For the process indicated in Claim 1 and for working even solutions of low
value the addition of well-developed crystals or a mass of crystals corresponding
thereto or the bringing of saturated solutions, or solutions which it is desired to
saturate, into contact with well-developed crystals or a corresponding mass of
crystals, substantially as set forth.
Dated this 16th dow of Feb 1900
J. C. MEWBURN.