A Process and Apparatus for the Direct Manufacture of Sugar Powder.
Year: 1899

page_text: Date of Application, 5th Dec., 1899-Accepted, 3rd Feb., 1900
COMPLETE SPECIFICATION.
A Process and Apparatus for the Direct Manufacture of Sugar Powder.
We, ARTHUR VALLEZ and FELIX GIRAUD, of Montpellier, France, Engineers, 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:-
Sugar powder, the consumption of which in many countries exceeds that of
lump sugar, is at present produced either in refineries by bruising to powder
sugar which had first to be refined in the form of loaves or slabs, or in sugar
factories by granulating number 3 sugar obtained in very fine grains by a special
centrifugal operation.
These methods of manufacture, besides being expensive, involve great loss of
sugar, and it is to get rid of these objections that we have devised the process
and apparatus for this purpose, which forms the object of the present invention.
Our process is based upon the following observations.
If an aqueous solution of sugar is boiled in a capsule, and if, when this solution
has reached the point of concentration termed "large broken," the source of heat
is removed and the solution is actively and continuously stirred by a spatula, the
water of the solution is observed to evaporate rapidly. The mass takes the form
of paste, then becomes white, and shortly pulverulent. After about 15 to 20
minutes all the water is evaporated and sugar in the state of dry powder is
obtained in the capsule. The explanation of the phenomenon is simple; in fact,
calculation shews that the latent heat of the concentrated boiling solu-
well
is specific as
that of solution, is greater
tion, heat which
Hence
than the heat necessary for vaporising all the water of the solution.
is results that the evaporation should be complete if by constant renewal of the
surfaces of evaporation, the operation is conducted with such rapidity that the
loss of heat by radiation and conduction may be neglected. Moreover, the knead-
ing movement to which the mass is subjected, prevents the formation of aggluti-
nations. Thus the sugar is obtained in a state of powder.
as
On this observation, which, so far as we know has never yet been published,
we have based the process hereinafter described for extracting from sufficiently
pure saccharine solutions, such as are produced in the course of manufacture in
sugar houses or refineries, all the sugar that they contain in a state of powder,
the degree of purity of the sugar being in complete correspondence with the
degree of purity of the solution.
This process, which constitutes on the whole the industrial realisation of the
laboratory experiment mentioned above, comprises the following operations.
The purified saccharine solution, whether it has been obtained by melting raw
sugar followed by purifying by the means at present in use, or whether it is
merely in the state of syrup like the green syrup of refineries, is concentrated in
0 a boiler open to the air heated by any suitable means, preferably by steam. The
is
solution, on arriving at the point of concentration termed "large broken
poured boiling into a special apparatus which, by pugging or kneading, effects
"

page_text: •
elimination of the water in the form of vapour, and thus transforms the mass
treated into sugar powder.
It is obvious that the agitation of the solution may of course be effected by
any horizontal or vertical appliance capable of stirring actively and continuously
the mass under treatment, but in order to perform this operation, we prefer to
employ the apparatus specially contrived for this particular operation, and shewn
by way of example, in a form which gives us the best practical results in side
elevation and in plan respectively by Figs. 1 and 2 of the annexed drawings.
It consists essentially of a rocking vessel a made of plate which in plan is of
rectangular form, the long sides being about twice as long as the short sides or
ends. The bottom of the vessel has the form of two cylindrical segments bl
which run into the opposite vertical walls of the vessel a, and meet in the middle,
these. geometrical axes being parallel to the long sides of the rectangle. Parallel
to these axes are arranged two shafts ed provided with agitating arms ee &c.,
and ff &c., the ends of these shafts passing through stuffing boxes gg in the
walls of the vessel a. These shafts by means of pinions h and toothed wheels i
are caused to rotate in the same direction by an external driving shaft k. The
plates perpendicular to the three shafts mentioned above, and forming the ends
of the vessel, have their lower parts prolonged in the form of trapezoids. The
shaft passes through two sleeves which are journalled in bearings mm and
serve as trunnions for the vessel a and also as bearings for the shaft k. The
bearings mm are supported in projecting beams n which thus carry the whole
apparatus and are solidly fixed at right angles to the shafts cdk on two masonry
foundations oo and have between them a free space sufficient to allow the vessel a
to rock on its trunnions 17. To the vessel a is suspended by angle iron stirrups p
a counterweight q, such as to cause the axis of rotation k to coincide with the
centre of gravity of the vessel with its accessories and its charge, which can there-
fore be turned upside down on its trunnions without requiring much force.
This invention is effected manually by working in proper direction the handler
of a winch having shafts s, t, pinion wheel and pinion gearing with a
toothed segment & fixed on the trapezoidal end of the vessel a. By this arrange-
iment the inverting movement is independent of the motions of the shafts ed
and k, the last of which is driven from any suitable motor by a band on a
pulley y on one end of the shaft. The agitating arms e and f are fixed at right
angles to their respective shafts c and d. They are of greater length than the
distance between these shafts and are arranged so that those on the one shaft
alternate with those on the other, and thus they do not interfere with each other.
The transverse section of these agitating arms is a square, one diagonal of which
is at right angles to the shaft. The arms on the shaft d have also rakes z at their
ends.
The apparatus operates as follows:-
When the solution is charged into the vessel a the apparatus is started with
such speed that the shafts ed make 30 to 40 revolutions per minute. Active
evaporation at once begins and the solution becomes pasty. Owing to the form
and arrangement of the agitators e and f, no part of the mass escapes their action.
Soon the paste whitens and becomes pulverulent. At the end of about a quarter
of an hour the evaporation is complete then the workman in charge working the
handle turns the apparatus over, while the shafts cd still continue to revolve.
In a few seconds all the sugar is thrown out by the agitators into a sacking hop-
per. The apparatus is then turned up again to its previous position ready for a
succeeding operation.
From what precedes will be understood the indisputable advantage of our
process which comprises a treatment more easy and cheap than that of other
processes, and substitutes a single very simple operation for the multiple opera-
tions of granulating, subjecting to centrifugal action, &c., also avoiding loss of
sugar. Among other applications of our process may be mentioned as character-

page_text: stic that for treatment of green sirups in refineries. These green sirups
urified or not by filtration through animal charcoal, furnish, when treated by
our process, sugar powder of a good appearance, and thus the so troublesome
production of refinery molasses is avoided and consequently the loss in refining
is reduced to less than one per cent.
We do not restrict ourselves to the precise details of construction shown, merely
by way of example in the annexed drawings, for these details, as well as the
forms, dimensions, proportions and materials mentioned in this specification,
may be modified to a certain extent without departing from the spirit of the
invention. Especially the desired result might be more or less completely at-
tained by constructing an apparatus the various arrangements of which may
resemble those above set forth, for instance, by employing a vessel with a flat
or a simple cylindrical bottom instead of one consisting of two cylindrical seg-
ments, or the agitating arms different forms or arrangements. The transmission
of motion to the several shafts of the apparatus may also admit of certain varia-
tions.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. The herein described manufacture of sugar powder by boiling a saccharine
solution, then, without farther heating, actively agitating the mass till it be-
comes pulverulent.
2. For agitating the boiled solution, apparatus constructed and operating sub-
stantially as described with reference to the drawings.
December 1899.
ABEL & LALIAL
Agents for the Applicants.