Improvements in the Production of Invert Sugar.
Year: 1890

page_text: Date of Application, 1st Nov., 1890
Complete Specification Left. 1st Aug.. 1891-Accepted, 5th Sept., .1891
PROVISIONAL SPECIFICATION.
Improvements in the Production of Invert Sugar.
We ALFRED WOHL and ALEXANDER KOLLREPP both of 104 Chaussée Strasse
Berlin in the Empire of Germany Doctors of Philosophy do hereby declare the
nature of this invention to be as follows:-
This invention relates to the production of invert sugar and refers more
particularly to the process described in the Specification of the British Patent
No. 16540 of 1889. The object of the present invention is to so improve this
process as to enable pure tasting invert sugar syrup to be obtained from inferior
raw sugars and from syrups and molasses. With this object the process is con-
ducted as hereinafter described whereby the inversion is combined with a thorough
and simultaneous purification of the product under treatment.
In order to obtain this purification we treat highly concentrated hot solutions of
sugar with steam or with cold or heated air or with a mixture of steam and heated
air which may be obtained by means of an injector for example the air being drawn
in by the action of a jet of steam. By means of this treatment we volatilise or
evaporate the liberated organic acids whose alkaline and calcareous salts are the
cause of the bad taste or flavour of raw sugar and the like. The facility and com-
pleteness with which the volatilisation or evaporation takes place are in proportion
to the elevation of the temperature the strength or volume of the current of steam
and air and especially to the degree of concentration of the solution of the acids
to be evaporated but on the other hand the degrees of concentration and of
temperature are limited by the ever increasing tendency to reversion of the invert
sugar and the formation of caramel. Now the evaporation of the acids proceeds
most energetically at the commencement of the process whilst the formation of
caramel and the reversion do not take place to any considerable extent until near
the end of the operation. On this account the raw sugar is melted or dissolved in
the first place with a small quantity of water and the required amount of acid the
external application of heat and the quantity of steam and air introduced being so
regulated that after the expiration of the period necessary for the inversion and for
the driving off or evaporation of the said acids the degree of concentration of the
saccharine solution is reduced by partial condensation of the steam exactly to the
point requisite for a useful syrup (75 to 80 degrees Baumé). In dealing with raw
sugar it is an advantage to have the sugar not completely dissolved at starting as
this enables a high degree of concentration of the completely dissolved acids of the
molasses to be maintained concurrently with a relatively low degree of concentration
of the saccharine solution.
In this process of treatment the alkalies which were previously combined with
the organic acids that are driven off remain behind in the form of salts of the acids
which were added to produce the inversion even when carbonate of lime (CaCO3)
has been used for the precipitation of these acids so that syrups highly deficient in
sugar yield products which are very rich in salts. In order to obviate this dis-
advantage we employ in addition to or in combination with the acids used in
conducting the process according to the invention covered by our former Patent
No. 16540 of 1889, fluor silicic acid or aluminous hydrofluoric acid. (aluminic
fluosilicic acid) that is to say a solution of alumina in hydrofluoric acid, these
substances being employed in quantities that are equivalent to the organic acids
capable of removal.
The said fluor silicic or silico fluoric acid or the said aluminous hydrofluoric acid
is introduced in a cold condition into the saccharine solution which should have a
density of about 50 degrees Baumé. The resulting precipitate of alkaline salts of

page_text: the silico fluoric acid or aluminous hydrofluoric acid is separated by filtration after
settling and the acid solution is then preferably concentrated in a vacuum or pre-
erably by the external application of heat and blowing up with heated air.
The remaining quantity of sulphuric or other acid necessary for the inversion
and the removal of the organic acids is then added and the syrup is treated as
previously described. In the subsequent operation of neutralising the acids with
carbonate of lime (CaCO3) the remainder of the alkalies remains in combination
with the non volatile acids of the molasses. To obtain a further purification from
salts the full equivalent weight of the alkalies combined with the volatile and
non volatile organic acids in silico fluoric or aluminous hydrofluoric acid may be
employed with or without the addition of another acid the syrup treated as
herein before described being saturated with carbonate of lime and filtered through
animal charcoal as the lime salts of the non volatile acids of the molasses which
now remain are more readily absorbed by carbon than the alkaline salts which
would otherwise be present. A clearing action on dark coloured syrups can be
obtained by causing the current of air injected into the acid solution to be
ozonised by one of the known processes; the action is more effective by a gentle
heating.
The following constitutes a further improvement in the process. When, in
treating inferior sugars, the acid employed for the inversion is to be allowed to
remain in the product in the form of a salt we employ for the purpose of the
inversion a mixture of acids in order that the taste or favour of no one of the salts
(such as NaCl, Na,SO, for example) may be perceptible or distinguishable in the
product, this mixture being substituted for a single acid and consisting preferably
of HCI, H₂SO, HNO, and H₂PO. By these means a relatively very small
quantity of each salt is produced.
Another improvement relates to the measurement or estimation of the quantity
of acid necessary and admissible for the inversion of highly concentrated solutions
of products that contain a relatively large quantity of mineral salts. In place of
estimating this quantity of acid according to the total amount of the mineral salts
we calculate it according to the amount of the salts of organic acids and proceed as
follows: Take 5 grammes for example of the product (raw sugar, syrup or
molasses) to be treated and carbonise it in a platinumi vessel. Mix the carbonaceous
(that is to say) the incompletely burned residuum with 5-10 of a normal acid
boil for a few minutes and then by return titration measure the amount of acid
consumed. This quantity gives directly in equivalents the amount of alkali which
was bound up in organic acids independently of the varying proportions between
the alkali, lime, and soda and also independently of the amount of calcium sulphate
and sodium chloride contained in the materials. By these means the liability to
reduction of the calcium sulphate to calcium sulphide in the heating process is
obviated. Such reduction can also be compensated by the employment of normal
sulphuric acid mixed with peroxide of hydrogen. The quantity of sulphuric acid
thus ascertained or the corresponding quantities of other acids is sufficient for the
inversion at a temperature of from about 100 to 110 degrees Centigrade. The time
required for the inversion amounts to from about half an hour to one hour within
which period the aforesaid organic acids can also be so far volatilised or evaporated
that the acidity of the syrup is reduced by at least one third. Consequently in
dealing with inferior products the acid employed may in many instances be allowed
to remain in the product in the form of a soda salt.
Dated this 1st day of November 1890.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in the Production of Invert Sugar.
We, ALFRED WOHL, of 113 Kurfürstendamm, Berlin, in the Kingdom of
Prussia, Doctor of Philosophy, and ALEXANDER KOLLREPP of 2 Charlotten-
strasse, Berlin aforesaid, Doctor of Philosophy, 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 the production of invert sugar and refers more
particularly to the process described in the Specification of the British Patent
No. 16540 of 1889. The object of the present invention is to so improve this
process as to enable pure tasting invert sugar syrup suitable for brewing purposes
to be obtained from inferior raw sugars as hereinafter described.
With this object
the process is conducted as hereinafter described, a highly concentrated acid sugar
solution being treated, while subjected to heat with air or with steam or with a
mixture of air and steam obtained by means of an injector drawing in the air for
example or by any other suitable means. By means of this treatinent the liberated
organic acids are volatilised in a short time without evaporation of the liquid.
This volatilisation which has a highly purifying effect upon the syrup takes place
with a degree of facility and completeness that is in proportion to the elevation of
the temperature the strength or volume of the current of steam and air and
especially to the degree of concentration of the solution of the acids to be volatilised
but on the other hand the degrees of concentration and of temperature of the sugar
solution are limited by the ever increasing formation of caramel. On this account
the concentration of the solution requires to be preferably under about 85 degrees
Baumé and the temperature about 110 degrees Centigrade. Moreover the vola-
tilisation of the acids proceeds most energetically at the commencement of the
process whilst the formation of caramel commences towards the end of the operation
only. On this account the raw sugar is melted or dissolved in the first place with
a small quantity of water say from about 10 to 15 per cent. and the required amount
of acid, the external application of heat and the quantity of steam and air
introduced being so regulated that after the expiration of the period necessary for
the inversion and for the driving off of the volatile acids the degree of concentration
of the saccharine solution is reduced by partial condensation of the steam exactly
to the point requisite for obtaining the most advantageous effect (75 to 80 degrees
Baune). In dealing with syrup the syrup should be in a highly concentrated form
being mixed with only so much water as is necessary to dilute the acids. This
treatinent is effected in an open or uncovered vessel heated by means of a hollow
bottom and in which a coiled steam pipe or worm is placed having a great number
of turns or convolutions and provided with numerous perforations or slots dis-
tributed as regularly as possible and arranged on opposite sides of the pipe in
order to obtain a uniform distribution of the current of air and steam in the body
of liquid.
In treating raw sugar the sugar must not be completely dissolved at starting
the concentration of the sugar solution is consequently lower but the acids of the
molasses being completely dissolved in a relatively small quantity of water possess
a high degree of concentration.
The purification by driving off the volatile acids may be effected by forcing in
air alone or air with a relatively small quantity of steam a corresponding quantity
of water preferably heated being introduced so as to maintain the desired degree
of concentration.
The measurement or estimation of the quantity of acid necessary in place of
being performed according to the method referred to in the Specification of the
Patent No. 16540 of 1889 is preferably accomplished by proceeding as next
hereinafter described-5 grammes for example of the product (raw sugar or

page_text: syrup) to be treated are carbonised in a platinum vessel. The residue obtained is
mixed with from 5 to 10 cubic centimetres of a normal acid and boiled for a few
minutes after which the amount of acid consumed is measured. This quantity
gives directly in equivalents the amount of alkali which was bound up in or
associated with the organic acids independently of the varying proportions between
the potash, lime and soda and also independently of the amount of calcium sulphate
and sodium chloride contained in the materials." When the inversion is performed
with a temperature of from 100 to 110 degrees Centigrade a quantity of sulphuric
acid equivalent to the organic acids or a quantity of another acid according to the
Specification of the Patent No. 16540 is sufficient; with a temperature of from
90 to 100 degrees Centigrade about more is required. The time required for
performing the inversion amounts to from about half an hour to one hour within
which period the aforesaid organic acids can also be so far volatilised or evaporated
that the acidity of the syrup is reduced by at least one third. Notwithstanding
the energetic treatment of the highly concentrated and highly heated sugar
solution with air and steam according to this universally applicable method of
measuring the quantity of acid, the formation of caramel is obviated with certainty.
Concurrently with the inversion the volatile organic acids can be completely
driven off so that the acidity of the invert sugar obtained is reduced by one third
and upwards.
When the quantity of sulphuric acid employed in the production of invert sugar
according to our aforesaid Patent No. 16540 is so large that it has to be converted
into calcium sulphate and removed by filtration the quantity of scum or froth
produced on adding the carbonate of lime (CaCO3) to the highly concentrated
acid solution is so great that the employment of large quantities is attended with
considerable inconvenience. In order to overcome this difficulty we employ in
place of the carbonate of lime described in the Specification to the Patent
No. 16540 a solution of saccharate of lime measured according to the degree of
acidity of the syrup the said solution being such as is obtained by saturating with
lime a saccharine solution of about 20 per cent. strength.
We are aware that the volatile acids have been expelled with or without
insufflation of air from syrups and molasses that have been rendered acid but in
this case the syrup or the molasses have always been highly diluted and afterwards
concentrated by evaporation and we believe that the process of driving off the
volatile acids, from hot concentrated sugar solutions as hereinbefore described
without evaporation and the conversion of raw beet sugar with simultaneous
purification into invert sugar syrup has not heretofore been attempted as no method
was known for conducting the inversion under the operation of the strong acids
upon highly heated concentrated sugar solutions nor was it known how to prevent
the formation of caramel.
Having now particularly described the nature of our said invention and in what
manner the same is to be performed we declare that what we claim is :-
In the production of invert sugar the removal of volatile organic acids by
treating a heated and concentrated acid solution of sugar with air or steam or with
a mixture of air and steam substantially as hereinbefore described.
Dated this 1st day of August 1891.
J. H. JOHNSON & Co.,
Agents.