Improvements in the Method of and Apparatus for Purification of Saccharine Syrups or Liquids.
Year: 1894

page_text: Date of Application, 21st Nov., 1894
Complete Specification Left, 21st Aug., 1895-Accepted, 21st Nov., 1895
TRUYIDIONAL SIMULTICATION.
Improvements in the Method of and Apparatus for Purification of
Saccharine Syrups or Liquids.
I, GUSTAVE GIN, of 15 Rue des Halles, Paris, in the Republic of France, do
hereby declare the nature of this invention to be as follows :-
This invention has for object a process for the complete purification of saccharine
syrups or liquids (hereinafter referred to as syrups) obtained by diffusion or other-
wise from beetroot, sugar-cane, or other sugar-yielding plant or plants; the said
process being such as to enable the whole of the sugar to be extracted direct in a
pure condition from the said syrups, without being preliminarily carbonated and
without producing any molasses or residual products.
My process consists essentially of the combination of the following operations:
(1) the clarification and partial purification of the syrup by means of an earthy
aluminate or an alkaline earth; (2) after filtering, the dissociation of the impurities
in the syrup by an electric current, using neutral electrodes, and, immediately
afterwards, the separation by the pseudo-electrolysis of the dissociated elements,
the bases being eliminated on the one hand, and the acids on the other, in such a
manner that the syrup will pass out freed from the whole of its impurities; and
(3) electrical osmosis of the eliminated liquids in order to separate therefrom the
sugar diffused through the diaphragms in the previous operation.
These operations are effected in practice as follows:-
To the syrup heated to about 80° C. there is added in a suitable ratio, which
varies with the nature and the degree of purity of the syrup aluminate of barium
or of strontium, or basic aluminate of calcium the last mentioned being the most
economical.
I employ the aluminates having 4 to 6 equivalents of calcium in preference to
those having one, two, or three equivalents, because the former dissolve in water,
and are instantly decomposed by contact with an acid syrup, whilst the second-
mentioned aluminates set under water and are but slowly decomposed.
Aluminate of calcium precipitates albuminoid substances, cellulose, gums, pectic
substances, and colouring matters. A portion of the organic acids is precipitated
in the form of organic salts of calcium or of aluminium. There is also precipitation
of phosphoric acid, magnesia, oxide of iron, etc.
A small quantity of potash and soda is carried off in the albuminoid precipitates.
A portion of the potash and soda, displaced from their compounds, remains in the
free state, and the syrup becomes decidedly alkaline.
The syrup is now freed from the precipitates and scum by filtering, after which
it passes to the electrolytic apparatus through a heating-apparatus by which its
temperature is raised to about 80° or 85° C. This heating, by diminishing the
electrolytic resistance of the syrup, considerably diminishes the consumption of
energy necessary for the electrolytic operations.
The electrolytic apparatus consists essentially of a series of chambers in which
the syrup circulates in a systematic manner.
Each chamber is divided into two parts. In the lower part which is not provided
with diaphragms, there takes place the electrolysis proper, which effects the
dissociation of the impurities. In the upper part, which is divided by diaphragms

page_text: into three compartiments, there takes place the pseudo-electrolysis which acts to
convey into their respective elimination compartments the electropositive and
electronegative elements which are merely dissociated by the electrolytic action
proper. In the lower part, or dissociation chamber, the anodes are of carbon, and
the cathodes are of iron. In the upper part or discharge chamber the electrodes
are situate in the elimination compartments on each side of the diaphragms; the
cathode is of iron, and the anode is of lead. By the action of the current, the
insoluble basis are freed and precipitated in the dissociation chamber, and the soluble
bases and acids are eliminated by pseudo-electrolysis in the negative and the
positive compartments. The acids fix on the anodes and combine with them to
form soluble or insoluble salts (acetates, malates, lactates etc.). which are precipi-
tated and will be finally removed by subsequent filtration.
It is easy to see the advantages that result from this division of the electrolytic
operation. First, the resistance of the electrolyte in the dissociation-chamber may
be reduced to any desired degree by bringing electrodes, which are not separated
by any diaphragm sufficiently close together. In the discharge chamber which is
situate between the diaphragms of the elimination compartments, the resistance of
the electrolyte is on the other hand, rather considerable on account of the distance
between the electrodes and of the interposition of two diaphragms. But in com-
pensation, the partitioning allows the concentration in the elimination-compartments,
particularly in the positive compartments, to be carried to such a degree that there
is caused to be precipitated an amount of lead salts the greater portion of which
would have been quite soluble bad the original degree of dilution of the syrup been
maintained.
In order to enable the great importance of this concentration to be better
appreciated, I shall take for example, chloride of lead, which would be considered
at first thoughts as being practically insoluble, whereas sugared water of a density
of 1.05 is capable of dissolving about 20 grammes of this salt per litre at a
temperature of 80° C. If it be considered that a normal syrup will furnish at the
most two grammes per litre, it will be seen that the precipitation would not take
place in the syrup itself if it remained at the same density.
I have here assumed the presence of only one dissolved salt. In the case of
several salts of lead simultaneously present, the limits of saturation are very
difficult to determine exactly; but the principle holds good nevertheless, and it is
certain that the direct electrolysis of a syrup with soluble anodes of any kind
acting without a partition and without the concentration enabled thereby, will
always leave behind in solution in the midst of the syrup under treatment an.
appreciable quantity of salts, which would on the contrary be precipitated in a less
dilute liquid.
1
The direct use of soluble anodes in a diffusion-syrup would therefore not effect
complete purification; this is possible only with the arrangement that I have.
adopted.
A few remarks may be added with reference to the arrangements just described.
The dissociation is effected in the presence of neutral anodes, upon the metal of
which the organic acids cannot satisfy their affinities. These acids react upon one
another and become oxidized. The result is nearly always carbonic acid and acids
of more complex formula which are capable of being more generally precipitated
in: the subsequent elimination than the original acid.
Thus, under these conditions, formic acid is eliminated spontaneously by oxida-
tion, forming carbonic acid and water. Butyric acid, in becoming oxidized,
produces carbonic, acetic, propionic, oxalic, and succinic acids. Gluco-saccharic
acid becomes split up into oxalic and saccharic acids. These reactions utilize
only the energies that are directly at disposal, and do not affect in any way the
sugar obtained.
The preceding statements show that the combination of the two operations
described, has for its result, the separation and the distribution into three distinct
vehicles of the substances contained in the syrup, one of these vehicles, which is

page_text: the original syrup subjected to the purifying process, containing nothing but pure
sugar.
But if the phenomena take place exactly as herein described, the purification can
only be complete if account be taken of certain disturbing influences which would
entail a loss of sugar if they were not corrected.
A certain amount of sugar diffuses through the diaphragms and passes into the
elimination-compartments. This diffusion is much less appreciable in the alkaline
liquid than in the acid liquid. To reduce the quantity of sugar that is thus diffused
and to recover that which it has not been possible to prevent from so diffusing, I
employ the following expedient :-
The original syrup. is divided into two portions say a and B. The portion a is
purified in the electrolytic apparatus just described which for convenience I will
call A; the portion ẞ is purified in a second electrolytic apparatus which I will
call B, which differs from the apparatus A only in that the elimination-compartments
contain neutral anodes of carbon instead of soluble anodes.
The eliminated acid liquid that passes from the apparatus A contains in solution
the lead salts resulting from the whole of the acids which were contained in the
portion a of the syrup and were not capable of being precipitated by the lead
anodes of the apparatus A. This eliminated liquid is introduced into the portion ẞ
of the syrup. By double decomposition, all of those acids of the syrup ẞ that are
capable of being so precipitated, are at once precipitated in the form of insoluble
lead salts. For the rest there is only exchange and substitution of acids, equivalent
for equivalent.
Thus in reality, the eliminated liquid of the portion a serves as a precipitating
plumbic re-agent for the portion ẞ to which it restores the sugar it had carried
away. It will be seen that by this expedient the least possible quantity of the
metal of the anode is dissolved, and that there no longer remains any soluble lead
salt in the syrup. if the quantities a and ẞ have been suitably determined. Purifica-
tion is effected in the electrolytic apparatus B in the same way as in the apparatus A,
with the sole difference that in the positive elimination-chambers the organic acids
are concentrated,. instead of the corresponding lead salts. In the case of a normal
syrup, the concentration may easily be carried up to a density greater than 1.05.
But if this degree of concentration be assumed, it will be seen that as it corre-
sponds per litre and for each acid taken separately, to 80 grammes of nitric acid,
200 grammes of formic acid, 220 grammes of lactic acid, 380 grammes of acetic
acid and of butyric acid, and so on, an accumulation of 200 grammes of various
acids per litre of eliminated liquid may be reckoned upon as a minimum. Now
since each litre of syrup furnished as a maximum only 4 grammes of acids that are
not capable of being precipitated by the lead anodes, it will be seen that 1 litre of
eliminated liquid will suffice for more than 50 litres of syrup to be purified.
Finally, if it be assumed that the syrup and the acid liquid are brought at last to
equal polarizations, then it is clear that the ratio of diffused sugar will amount at
most to but is only a very small fraction of the syrup subjected to the
В
50
purifying process, so that the ratio cannot be greater than 200
The eliminated liquids are sent into apparatus I will call C and D, provided_with
compartments formed by diaphragms through which passes a current that produces
electric osmosis and consequently the separation of the basic or acid principles
from the sugar carried over.
For basic electric osmosis the anodes and the cathodes are of iron; the anodes
dip into the liquid to be freed from the. bases in solution; these bases pass to the
cathodes in the elimination-compartments, whilst the sugar remains in the positive
compartments whence it is restored to the general circulation.
For acid electric osmosis, the anodes and the cathodes are of carbon; the
cathodes dip in the liquid undergoing purification and the anodes are situated in the
elimination-compartments. The acids become concentrated in these compartments,

page_text: and the sugar remains in the negative liquid which is then led to the apparatus which
receive the purified syrup. It is true that in this electric osmosis there is a fresh
loss of sugar by diffusion, but if it be considered that such loss is merely a very
small fraction of a fraction of the entire amount of sugar, and that the last
mentioned fraction is less than 200, as hereinbefore stated, it is clear that the final
loss can be neglected.
It is advisable to regulate these last two operations in such a manner that the
purified basic liquid shall still possess a slight alkalinity, which will be imparted
to the mixture with the purified syrup.
It will be seen that the result of these operations is to produce a syrup of a
degree of purity which may be as perfect as possible. The boilings resulting
therefrom are quite pure, so that the drainings or syrupy water removed by
centrifugal action from the said boilings will still be of a purity about equal to that
of the best first boilings produced by the ordinary processes.
It will be understood that no molasses can be produced other than that which
may result from the use of beetroot of bad quality containing glucose.
In order to enable the process herein before described to be readily carried into
practice, I shall now proceed to describe apparatus whereby the said process can be
worked systematically.
An electrolytic apparatus such as is herein called A, comprises a wooden trough
the lower part of which is divided by a longitudinal and by transverse partitions
into a series of pairs of chambers which I term dissociation-chambers. In each of
these chambers are situate a carbon anode and an iron cathode, mounted on a
wooden frame the bottom end of which rests on the bottom of the chamber, in
which it fits pretty closely.
The upper portions of the side walls of the trough and of the longitudinal
partition are provided with grooves in which fit the elimination-compartments
which are furnished with porous side walls and with electrodes and form between
them discharge chambers which may be considered as extensions of the dissociation-
chambers.
In the said apparatus A. the electrodes of the positive elimination-compartments
are of lead; and in the electrolytic apparatus herein called B they are of carbon.
The circulation of the eliminated liquids and of the syrup take place in the same
direction. The syrup enters at the lower part of the first pair of dissociation-
chambers into which it flows by means of a pipe; it passes out at the upper part
of the pair of discharge-chambers immediately above the said chambers, flowing
into suitable channels; it then passes into the next pair of dissociation-chambers
by vertical passages which discharge into the lower part of these chambers. The
syrup thus enters each chamber in succession at its lower part and passes out from
the same at its upper part, thereby pursuing the longest course through the several
chambers from end to end of the trough.
The eliminated liquids are caused to circulate in a zig-zag course by means of
two sets of suitably arranged pipes, one set serving for the alkaline liquid and the
other set for the acid liquid. The alkaline and the acid eliminated liquids pass out
through suitably arranged cocks.
Each pair of dissociation-chambers is furnished with a discharge-cock. The
elimination-compartments are also provided with cocks for the discharge of the
precipitates.
In order to prevent the adhesion to the metal electrodes of solid deposits or
gaseous accumulators, and the polarization resulting therefrom, arrangements may
be provided for agitating the bath or the electrodes, or for brushing the latter.
Mechanical arrangements for these purposes are usually very cumbersome, and
complicate the apparatus considerably. The method I employ is very simple and
consists in intermittently blowing in air under pressure in such a manner as to
cause it to pass over the surface of the electrodes and thereby to collect the gas
bubbles and detach the polarizing deposits.

page_text: The circulation of the liquids in the compartments of the apparatus herein
called C & D is similar to that in the apparatus herein called A & B, but the
arrangement is much simpler. Such apparatus is provided at one end with an inlet
for the liquid from which the sugar is to be recovered, and at the other end with an
outlet for the liquid when purified. Also with a supply-pipe for the eliminated
liquid, and with an outlet therefor. Each compartment is furnished with a
discharge-cock.
Improvements in the Method of and Apparatus for Purification of
Saccharine Syrups or Liquids.
I, GUSTAVE GIN, of 15 Rue des Halles, Paris, in the Republic of France, 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 has for object a process for the complete purification of saccharine
syrups or liquids (hereinafter referred to as syrups) obtained by diffusion or
otherwise from beetroot, sugar-cane, or other sugar yielding plant or plants; the
said process being such as to enable practically the whole of the sugar to be
extracted directly in a pure condition from the said syrups, without being
preliminarily carbonated and without producing any molasses or residual products.
My process consists essentially of the combination of the following operations :-
(1) the clarification and partial purification of the syrup by means of a basic
aluminate of lime; (2) after filtering, the dissociation of the impurities in the
syrup by an electric current using neutral electrodes, and, immediately afterwards,
separation by pseudo-electrolysis of the dissociated elements, the bases being
eliminated on the one hand, and the acids on the other, in such a manner that the
syrup will pass out freed from the whole of its impurities; and (3) electrical
osmosis of the eliminated liquids in order to separate therefrom the sugar diffused
through the diaphragms in the previous operation.
These operations are effected in practice as follows:-
To the syrup heated to about 80° C. there is added in a suitable ratio, which
varies with the nature and the degree of purity of the syrup, basic aluminate of
calcium.
I employ the almuminates having 4 to 6 equivalents of calcium in preference to
those having one, two, or three equivalents of calcium, because the former dissolve
in water, and are instantly decomposed by contact with an acid syrup, whilst the
secondly mentioned aluminates set under water and are but slowly decomposed.
Aluminate of calcium precipitates albuminoid substances, cellulose, gums, pectic
substances, and colouring matters. A portion of the organic acids is precipitated
in the form of organic salts of calcium or of aluminium. There is also precipitation
of phosphoric acid, magnesia, oxide of iron, etc.
A small quantity of potash and soda is carried off in the albuminoid
precipitates.
A portion of the potash and soda, displaced from their compounds, remains in
the free state, and the syrup becomes decidedly alkaline.
The syrup is now freed from the precipitates and scum by filtering, after which
it passes to the electrolytic apparatus through a heating-apparatus by which its

page_text: '
=
'
temperature is raised to from about 80° to 85° C. This beating, by diminishing
the electrolytic resistance of the syrup, considerably diminishes the consumption
of energy necessary for the electrolytic operations.
The electrolytic apparatus consists essentially of a series of chambers in which
the syrup circulates in a systematic manner.
Each chamber is divided into two parts. In the lower part, which is not
provided with diaphragms, there takes place the electrolysis proper which effects
the dissociation of the impurities. In the upper part, which is divided by
diaphragms into three compartments, there takes place the pseudo-electrolysis,
which acts to convey into their respective elimination-compartments the electro-
positive and electro-negative elements which are merely dissociated by the
electrolytic action proper. In the lower part, or dissociation-chamber, the anodes
are of carbon, and the cathodes are of iron. In the upper part or discharge
chamber, the electrodes are situate in the elimination-compartments on each side of
the diaphragms; the cathode is of iron, and the anode is of lead. By the 'action
of the current, the insoluble bases are freed and precipitated in the dissociation-
chamber, and the soluble bases and acids are eliminated by pseudo-electrolysis in the
negative and positive compartments. In the positive compartments, the acids fix
on the anodes and combine with them to form soluble or insoluble salts (acetates,
malates, lactates etc.) which are precipitated and will be finally removed by
subsequent filtration.
It is easy to see the advantages that result from this division of the electrolytic
operation. First, the resistance of the electrolyte in the dissociation-chamber can
be reduced to any desired degree by bringing the electrodes, which are not
separated by any diaphragm, sufficiently close together. In the discharge-
chamber, the electrical resistance of the electrolyte is, on the other hand, rather,
considerable on account of the distance between the electrodes and of the inter-
position of two diaphragms. But in compensation, the partitioning allows the
concentration in the elimination-compartments, particularly in the positive
compartments, to be carried to such a degree that there is caused to be
precipitated, an amount of lead salts, the greater portion of which would have
been quite soluble had the original degree of dilution of the syrup been
maintained..
54
In order to enable the great importance of this concentration to be better
appreciated, I shall take for example, chloride of lead, which would be considered
at first thoughts as being practically insoluble, whereas sugared water of a density
of 105 is capable of dissolving about 20 grammes of this salt per litre at a
temperature of 80° C. If it be considered that a normal syrup will furnish at the
most two grammes per litre, it will be seen that the precipitation would not take
place in the syrup itself if it remained at the same density.
I have here assumed the presence of only one dissolved salt.... In the case of
several salts of lead simultaneously present, the limits of saturation are very
difficult to determine exactly; but the principle holds good nevertheless, and it is
certain that the direct electrolysis of a syrup with. soluble anodes of any kind
acting without a partition and without the concentration that can be obtained
thereby, will always leave behind in solution in. the midst of the syrup under
treatment, an appreciable quantity of salts, which would on the contrary be
precipitated in a less dilute liquid.
The direct use of soluble anodes in a diffusion-syrup would therefore not effect
the complete purification; this is possible only with the arrangement that I have
adopted.
A few remarks may be added with reference to the arrangements just described.
The dissociation is effected in the presence of neutral anodes, upon the metal of
which the organic acids cannot satisfy their affinities. These acids re-act upon one
another and become oxidized. The result is nearly always carbonic acid and acids
of more complex formula, which are capable of being more generally, precipitated
in the subsequent elimination than the original acid,

page_text: Thus, under these conditions, formic acid is eliminated spontaneously by
oxidation, forming carbonic acid and water. Butyric acid, in becoming oxidized,"
produces carbonic, acetic, propionic, oxalic, and succinic acids. Gluco-saccharic
acid becomes split up. into oxalic and saccharic acids. These re-actions utilize only
the energies that are directly at disposal, and do not affect in any way the sugar..
obtained.
The preceding statements show that the combination of the two operations:
described, has for its result the separation and the distribution into three distinct
vehicles of the substances contained in the syrup, one of. these vehicles, which is .
the original syrup. subjected to the purifying process, containing nothing but pure
sugar.
But if the phenomena take place exactly as herein described, the purification
can only be complete if account be taken of certain disturbing influences which
would entail ai loss of sugar if they were not corrected.
A certain amount of sugar diffuses through the diaphragms and passes into the
elimination-compartments. This diffusion is nuch less appreciable in the alkaline
liquid than in the acid liquid. To reduce the quantity of sugar that thus diffuses
and to recover: that which it has not been possible to prevent from so diffusing,
I employ the following expedient:-
The original syrup, is divided into two portions say a and B. The portion a is
purified in the electrolytic apparatus just.described which for convenience I will
call A; the portion ẞ is purified in a second electrolytic apparatus which I will
call' B, which differs from the apparatus A only in that the elimination-compart-
ments contain neutral anodes. of carbon instead of soluble anodes.
1
$
•
I
The acid liquid that passes from the positive elimination. compartments of
apparatus A, and hereinafter called the eliminated liquid, contains in solution, the
lead salts: resulting from the. whole of the acids which were contained in the
portion a of the syrup and were not capable of being precipitated by: the lead
anodes of the apparatus A. This eliminated liquid is introduced into the portion ẞ
of the syrup. By.double. decomposition, all of these acids of the syrup B that are
capable of being so precipitated, are at once precipitated in the form of insoluble
lead salts. For the rest there is only exchange and substitution of acids, equi->
valent for equivalent. Thus in reality, the eliminated liquid of the portion a'serves
as a precipitating plumbic re-agent for the portion ẞ to which it restores the sugar I
it had carried away. :
It will be seen that by this expedient, the least possible quantity of the metal,
of the anode is dissolved, and that there no longer remains any soluble lead salt in
the syrup if the quantities and ẞ have been suitably determined. Purification
is effected in the electrolytic apparatus B, in the same way as in the apparatus. A,
with the sole difference that in the positive elimination-chambers, the organic acids;
that are ordinarily present in the syrup are concentrated, instead of the corre
sponding. lead salts. In the case of a normal syrup, the concentration may easily,
be carried up to a density greater than 1.05. But if this degree of concentration
be assumed, it will be seen that as it corresponds per litre and for each acid taken
separately, to 80 grammes of nitric acid, 200 grammes of formic acid, 220 grammes
of lactic acid, 380 grammes of acetic acid and of. butyric acid and so on, an
accumulation of 200 grammes of various acids per litre of eliminated liquid may be
reckoned upon as. a. minimum. .
Now since each litre of syrup furnishes as a maximum only 4 grammes of acids
that are not capable of being precipitated by the means employed, it will be seen
that 1 litre of eliminated liquid will suffice for more than 50 litres of syrup to be
purified. Finally if it be assumed that the syrup and the acid liquid are brought
at last to equal polarizations, then it is clear that the ratio of diffused sugar will
E
50
amount at most.to ; but, ẞ is only a very small fraction of the syrup subjected
to the purifying process, so that the ratio cannot be greater than 30.
The eliminated liquids from the positive, compartments of apparatus A and B,
:
.1
'
r
}

page_text: and those from the negative compartments of the said apparatus, are respectively
sent into apparatus I will call C and D, provided with compartments formed by
diaphragms through which passes a current that produces electric osmosis, and
consequently the separation of the basic or acid principles from the sugar carried
over into the eliminated liquids.
For basic electric osmosis, that is to say, electric osmosis of the eliminated basic
liquids from the negative compartments of apparatus A and B, the anodes and the
cathodes of apparatus D are of iron. The anodes dip into the liquid to be freed
from the bases in solution, and these bases pass to the cathodes in the elimination-
compartments of the apparatus, whilst the sugar remains in the positive com-
partments, whence it is restored to the general circulation.
For acid electric osmosis, that is to say, electric osmosis of the eliminated acid
liquid passing from the positive compartments of apparatus A and B, the anodes
and the cathodes of apparatus C are of carbon; the cathodes dip in the liquid
undergoing purification and the anodes are situated in the elimination compartments
of such apparatus. The acids become concentrated in these compartments, and the
sugar remains in the negative liquid which is then led to the apparatus which
receive the purified syrup. It is true that in this electric osmosis there is a fresh
loss of sugar by diffusion, but if it be considered that such loss is merely a very
small fraction of a fraction of the entire amount of sugar, and that the last
mentioned fraction is less than 200, as hereinbefore stated it is clear that the final
loss can be neglected.
It is advisable to regulate these last two operations in such a manner that the
purified basic liquid shall still possess a slight alkalinity, which will be imparted to
the purified syrup with which the purified basic liquid is mixed.
It will be seen that the result of these operations is to produce a sugared syrup
of a degree of purity which may be as perfect as possible. The boilings resulting
therefrom are quite pure, so that the drainings or syrupy water removed by
centrifugal action from the said boilings will still be of a purity about equal to that
of the best first boilings produced by the ordinary processes. It will be understood
that no molasses can be produced other than that which may result from the use
of beetroot of bad quality containing glucose.
In order to enable the process hereinbefore described to be readily carried into
practice, I shall now proceed to describe apparatus whereby the said process
can be worked systematically, referring for this purpose to the accompanying
drawings in which,
Fig. 1 shows partly in side elevation and partly in longitudinal section, an
electrolytic apparatus such as hereinbefore referred to as A;
Fig. 2 is a plan partly in horizontal section and with the elimination-compartments
removed in the lower and part of the upper half of the figure; and
Fig. 3 is a cross section of the apparatus A, with both the elimination-
compartments and the anodes and cathodes of the dissociation-chambers removed
in the right hand portion.
This electrolytic apparatus comprises a wooden trough T the lower part of which
is divided by a longitudinal partition L and by transverse partitions L₁, into a series
of transverse pairs of chambers d which 1 term dissociation-chambers. In each
of these chambers are situate a carbon anode and an iron cathode, mounted on a
wooden frame the bottom end t of which rests on the bottom of the chamber in
which it fits pretty closely.
The upper portions of the side walls of the trough T and of the longitudinal
partition L are provided with grooves in which fit the elimination-compartments e, f
which are furnished with porous side walls and with electrodes and form between
them chambers d' which may be considered as extensions of the dissociation
chambers d. In the said apparatus A the electrodes of the positive elimination-
compartments are of lead and in the electrolytic apparatus herein called B,
which is otherwise similar to A, they are of carbon.
The circulation of the eliminated liquids and of the syrup take place in the

page_text: same direction. The syrup enters at the lower part of the first pair of dissociation
chambers d into which it flows by means of a pipe a; it passes out at the upper
part of the pair of discharge chambers d' immediately above the said chambers d,
flowing into suitable channels g; it then passes into the next pair of dissociation-
chambers d by vertical passages g which discharge at g" into the lower part of
these chambers. The syrup thus enters each chamber in succession at its lower
part and passes out from the same at its upper part, thereby pursuing the longest
course through the several chambers d d from end to end of the trough 'T.
The eliminated liquids are caused to circulate by any suitable means through
two sets of suitably arranged pipes h k, one set (4) serving for the alkaline liquid
passing from the negative compartments e and the other set k, for the acid liquid
passing from the positive compartiments f. The alkaline and the acid eliminated
liquids pass out through suitably arranged cocks and m respectively. Each pair of
dissociation chambers d is furnished with a discharge-cock n. The elimination-
compartments e, f are also provided with cocks (not shown), for the discharge of the
precipitates produced therein.
In order to prevent the adhesion to the metal electrodes, of solid deposits
or gaseous accumulations, and the polarization resulting therefrom, arrange-
ments may be provided for agitating the bath or the electrodes, or for brushing
the latter. Mechanical arrangements for these purposes are usually very
cumbersome, and complicate the apparatus considerably. The method I employ is
very simple and consists in intermittently blowing in air under pressure in such a
manner as to cause it to pass over the surface of the electrodes and thereby to
collect the gas bubbles and detach the polarising deposits. The arrangements
necessary for carrying out this method of preventing polarization being very simple,
it has not been considered necessary to describe them in detail, nor to show them
in the accompanying drawings, in order not to obscure the figures.
The apparatus herein called C and D for the electrical osmosis of the eliminated
liquids from the positive and negative compartments respectively of apparatus A
and B are illustrated in Figs. 4, 5, and 6 which are respectively a side elevation, a
diagrammatic plan, both partly in section, and a cross section of one of such
apparatus, the other being similar to it.
The circulation of the liquid in each of the compartments of such apparatus is
similar to that in the apparatus herein called A and B, and hereinbefore described, but
the arrangement, as will be seen, is much simpler. Such apparatus is provided at
one end with an inlet a' for the liquid from which the sugar is to be recovered, and
at the other end with an outlet f1 for the liquid when purified. Also with a
supply pipe for the eliminated liquid, and with an outlet g¹ therefor. Each
compartment is furnished with a discharge-cock, are pipes connecting the
chambers d* in a zig-zag manner, and g² are channels and g³ vertical passages
serving to place the upper part of each chamber c* in connection with the lower
part of the next succeeding chamber C*.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In the purification of syrup, subjecting the same to the action of a basic
aluminate of calcium substantially as herein set forth so as to effect a preliminary
precipitation of a portion of the impurities and colouring matters, contained in the
said syrup.
2. In the purification of syrup, subjecting the syrup to the electrolytic action of
an electric current, using neutral electrodes, for the purpose of dissociating the
impurities present in the syrup, and afterwards subjecting it to the action of an
electric current for the purpose of effecting the separation and elimination by
pseudo-electrolysis of the dissociated basic and acid matters, the pseudo-electrolysis
being effected partly with soluble anodes and partly with neutral anodes as set
forth.

page_text: 3. In the purification of syrup according to the preceding claim, dividing the
pseudo-electrolysis into two operations, one being effected with soluble anodes and
the other with neutral anodes and using as a re-agent in the second operation the
eliminated acid liquid resulting from the first operation, substantially as herein
described for the purpose specified.
4. In the purification of syrup, subjecting the eliminated liquids to electric
osmosis substantially as herein described for the purpose of recovering from such
liquids the sugar that has diffused through the diaphragms of the electrolytic
apparatus used for effecting the separation of the basic and acid matters from the
syrup by pseudo-electrolysis.
5. For purifying sugar-juices, the herein described method of purifying syrup
by subjecting the syrup to a preliminary clarifying and purifying treatment by
means of a basic aluminate of calcium, then to electrolytic dissociation using neutral
electrodes, then to pseudo-electrolysis, using soluble anodes for one fractional portion
of the syrup and neutral anodes for the other portion, adding the eliminated
acid liquid of the first portion of syrup to the second portion of syrup, and subjecting
the eliminated acid and basic liquids to electric osmose substantially as described
for the purpose specified.
6. For carrying out the method of purifying syrup herein specified, apparatus
constructed, arranged and operating substantially as hereinbefore described with
reference respectively to and shown in Figs. 1 to 3 inclusive, and in Figs. 4 to 6
inclusive of the accompanying drawings or modified as set forth.
T
1005
t day of August 1905
For the Applicant,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.