Improvements in the Granulation of Crystallisable Liquids, and especially of the By-products of Sugar Manufacture.
Year: 1896

page_text: Date of Application, 20th Oct., 1896-Accepted, 18th Sept., 1897
COMPLETE SPECIFICATION.
Improvements in the Granulation of Crystallisable Liquids, and
especially of the By-products of Sugar Manufacture.
I, JAN GROSSE, of 15 Proresnaja Kiew, Russia, Engineer, 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:―
The present invention has for its object to considerably shorten the period
usually occupied in the granulation of concentrated sugar juice and other
crystallisable liquids and is carried into effect by heating the impure mass to be
crystallised in its lowest layers only, whilst in a complete or partial vacuum and
whilst imparting to it at the same time a mechanical motion from the bottom
upwards, the arrangement being such as to subject the several particles of the
mass to a rapid variation of temperature and to a continuous and uniform
evaporation.
Crystallisation is specially dependent on the density and the temperature of the
solution, and when a solution is subjected when saturated at a certain temperature,
to cooling, then crystallisation immediately takes place.
As water is liberated during the formation of the crystals or during the increas-
ing of the size of the crystals, which acts to dilute the remaining part of the
solution, evaporation must progress in proportion as the crystallisation progresses
so that the remaining solution that is to be crystallised shall remain saturated.
According to my invention it is possible to readily effect such evaporation and
to convey the necessary heat according to requirement to the mass by heating its
lower layers, and mechanically agitating.
It will be understood that as in a concentrated liquid which is heated to a boiling
temperature in a complete or partial vacuum, a higher temperature obtains in its
lower layers than in its upper layers in consequence of the pressure of the head of
liquid, a considerable promotion of the crystallisation will be effected when the
several particles of a heated saturated solution situated at the bottom of the pan or
vessel are conveyed from the lower hotter layers into the upper and colder layers
as by this means the mass is uniformly evaporated and reduced to a lower uniform
temperature. The principle of the invention is based upon this fundamental fact.
According to this process crystallising pans or vessels of any shape can be
employed which are provided externally with the fittings of an ordinary vacuum
apparatus, are capable of being hermetically closed, and are also provided with a
mechanical stirring device, and are adapted at their lower part to be heated by
means of steam, hot air, hot gases, or the like in double bottoms, heating coils,
heating pipes, or caloriferes.
The mechanical stirring device may consist of helical blades or vanes, secured
upon a vertical shaft situated in the centre of the vacuum apparatus mounted in
suitable bearings; the upper extremity of such vertical shaft projecting through
a suitable gland at the top of the apparatus and being caused to rotate by any

page_text: suitable arrangement of gear, whereby in operation the liquid is caused to con-
tinuously move upwards. For the purpose of heating, a coil of piping is arranged
in the lower part of the apparatus through which steam or other heating agent
may be caused to pass.
When effecting the evaporation or granulation of concentrated sugar juice in
accordance with my invention I deprive the vacuum pan of air and then partly fill
with the mass or liquid to be crystallised which has been previously concentrated
to some extent according to requirement. The contents of the vessel are then
brought to the boiling temperature corresponding to the absolute pressure. At
the same time the mechanical stirring device provided in the interior of the vessel
or pan is set in operation. As the contents are being continually mingled
together further and uniform heating and evaporation progresses, and as soon as
the solution has reached in its lower part a degree of saturation corresponding to
the temperature for the time being, the stirring arms act to convey the several
particles of this mass from the lower parts into the upper colder layers so that
crystallisation will commence at once, although at first only very fine crystals are
produced.
The concentration of the first supply is continued in the same manner until a
sufficient quantity of these fine crystals are produced.
Now according as it is desired to produce finer or coarser crystals further
quantities of the by product to be crystallised are drawn into the apparatus in
larger or smaller quantities, in a more concentrated or more dilute condition and
in a colder or hotter state, and the water contained therein is continually
evaporated by heating the lower layers with continual mechanical agitation of the
several particles from the bottom to the top for the purpose of producing a further
formation of crystals or an increase in the size of the crystals. When in this
manner by adding and concentrating the by product in successive quantities the
apparatus has become filled to about seven eighths of its capacity the heating is
discontinued, but the mass is still further agitated in the vacuum until the
requisite cooling and the final crystallisation is effected.
If the crystallisation of all the by products is to be effected continuously as they
are produced in working the number and size of the crystallising vessels or pans
must be chosen in accordance with the requirements of the particular manufacture.
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. A process for effecting the granulation of concentrated sugar juice or of other
impure or difficultly crystallisable liquids and more especially the after products
of the manufacture of sugar consisting in mechanical stirring of the juice or liquid
within the vacuum or granulating pan and the heating of the lower portions or
layers of the mass, the arrangement being such that the lower layers require a
higher temperature than the upper layers and a continuous upper movement is pro-
duced which effects the cooling of the mass and continuous rapid evaporation, so
that crystallisation is considerably accelerated substantially as and for the purpose
hereinbefore described.
2. In the granulation of concentrated sugar juice or of other impure or
difficultly crystallisable liquids and more especially the after products of the
manufacture of sugar the evaporation and crystallisation of the mass by
mechanical stirring substantially as and for the purpose hereinbefore described.
3. A process for effecting the granulation of concentrated sugar juice or of other
impure or difficultly crystallisable liquids and more especially the after products
of the manufacture of sugar substantially as and for the purpose" hereinbefore
described.
4. In the granulation of concentrated sugar juice or of other impure or difficultly
crystallisable liquids and more especially the after products of the manufacture of

page_text: sugar the final crystallisation of the mass by further mechanical stirring after
heating substantially as described.
Dated this 20th day of October 1896.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.