Improvements in Refining Sugar.
Year: 1892

page_text: [The decision of the Chief Examiner, acting on behalf of the Comptroller, of the
6th day of October 1892, allowed, under Section 18 of the Patents, &c. Act,
1883, an Amendment of this Specification.]
Date of Application, 9th Jan., 1892-Accepted, 13th Feb., 1892
4
COMPLETE SPECIFICATION (AMENDED).
Improvements in Refining Sugar.
I, EUGEN LANGEN, of Cologne, Germany, Manufacturer, 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 :-
This invention relates to an improved method of refining sugar whereby all the
polarisation-sugar obtainable by recrystallisation from the after-products of the
refining, is led back into the circuit of the refining process in the form of an almost
chemically pure sugar solution, so that the refining is carried out without after-
products, such as result from the present mode of refining.
For this purpose, the dissolved raw sugar, after filtration, is boiled down to a
granular filling mass, in the usual manner and thus the No. I product of the
refining process is obtained.
The essential feature of the invention consists in the now following treatment of
the after-products resulting from this first treatment.
The first syrup, the so called green syrup, is thickened to a stringy or granular
consistency, the mass is brought to renewed crystallisation according to the
"Wulff" or " Bock"
process of crystallisation under motion with inoculation by
means of sugar crystals and this mass This process, which forms no part of my
present invention consists in introducing the thickened mass into vessels in which it is kept
continuously in motion by means of suitable stirrers or agitators while a regulated
lowering of the temperature is effected by suitable known means, such as by the
introduction of hot or cold water into the jacket of the vessel in accordance with the
required separation of sugar from the mass. At the same time the mass is inoculated
with extraneous sugar crystals, which induce or accelerate the crystallization of the sugar
therein.
The crystalline mass thus produced is divided according to the known principles
of fractionated washing ("Steffens process ") into a whitish crystalline magma,
which is the No. II product, and low grade syrup.
When the last washing liquor passing away from the mass has been pumped off
as much as possible, water is led in thin streams distributed as uniformly as possible
over the surface of the mass.
The water becomes saturated with sugar and this solution penetrates through the
mass and serves as a repeated liquoring, whereupon the further quantity of water
effects the solution of the entire contents of the washing vessel.
If this sugar solution on issuing from the bottom of the washing vessel is at first
somewhat coloured, it is used as boiling liquor for the No. I product, while the
solution afterwards pumped out until the final solution of the entire contents of the
washing vessel, is employed for the preparation of the clear liquor.
The low grade syrup first pumped off from the No. II product as above described,
is again thickened by evaporation, and is also made to crystallise out according to
the method of crystallisation under motion.
The mass thus produced is then subjected to centrifugal action and the resulting
sharp grained yellowish granular sugar (No. III product) is employed for the
crystal inoculation for the crystallising of the No. II product.

page_text: This sugar of No. II product consequently passes backward one station in the
factory, as it unites in the same crystals with the sugar (No. III product) separated
from the green syrup of the No. II product and then, after this mass has been
subjected to fractional washing as above described it is passed, together with the
sugar of No. III product, back into the circuit of the refinery as white sugar
solution, polarising nearly 100 per cent.
As a rule the syrup thrown off from No. III product will be sufficiently low in
value for leading it back to the station for treating molasses or for selling it as
molasses.
If this is not the case, the syrup is again subjected to the process of crystallisa-
tion under motion, and the sugar obtained as No. IV product is introduced either
into the process of No. III product or into that of No. II product, as crystal
generator.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A method of refining sugar wherein all polarisation sugar obtainable by
recrystallisation from the after products of the refining process, is led back into
the circuit of the refining process in the form of an almost chemically pure sugar
solution, this being effected by the employment of the granular sugar obtained by
crystallisation in motion from the thickened low grade syrups, as crystal generator
in the next better mass, the resulting combined crystalline product being subjected
to systematical washing by means of sugar solution.
Dated this 8th day of January 1892.
ABEL & IMRAY,
Agents for the Applicant.