IMPROVEMENTS IN THE MANUFACTURE OF SUGAR
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
GWYNNE, of Sussex Square, in the County of Middlesex, Esquire, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great. Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-seventh day of
February, One thousand eight hundred and fifty, in the thirteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
the said George Gwynne, his exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said George Gwynne,
my exors; admors, and assigns, or such others as I, the said George
Gwynne, my exors, aditiors, or assigns, should at any time agree with, and
no others, from time to time and at all times during the term of years
therein expressed, should and lawfully might make, use, exercise, and vend,
within England and Wales and the Town of Berwick-upon-Tweed, and in the
Islands of Guernsey, Jersey; Alderney, Sark, and Man, and in all Her said
Majesty's Colonies and Plantation's abroad, my Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF SUGAR;" in which said Letters Patent is contained a
proviso that I, the said George Gwynne, shall cause a particular description
of the nature of my said Invention, and in what manner the same is to be
performed, by an instrument in writing under my hand and seal, to be enrolled
in Her said Majesty's High Court of Chancery within six calendar months
next and immediately after the date of said in part recited Letters Patent,
-

page_text: as m and by the same, reference being thereunto nad, will more runy and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Gwynne, do hereby declare that the nature of my Invention, and in
what manner the same is to be performed, are fully described and ascertained
in and by the following description thereof, (reference being had to the Draw-
ings hereunto annexed, and to the figures and letters marked thereon, that is
to say :-
The first part of my Invention will be found sufficiently detailed in the
following description.
A suitable oxide of lead, say, for example "lithage," is moistened with
water, and is then subjected to a process of grinding until it is reduced to a
smooth paste. When this is accomplished, twice its weight of refined sugar
is added to it, and the grinding continued until these materials are properly
combined. This result may be ascertained by putting a small portion of the
mixture into a glass, stirring it up with some water, and, after a few minutes'
repose, slowly pouring it away. If the operation is perfect, no oxide of lead
in a free state will be found at the bottom of the glass. This combination,
for distinction sake, I shall call saccharide. of lead. During the grinding,
water is to be added from time to time for the purpose of keeping the mate-
rials in a state of moderate consistency, and the generation by friction of such
a degree of heat as will darken the sugar should be avoided. When the lead
and sugar have properly combined, the mixture should be allowed to remain
for forty-eight hours, when the saccharide of lead will be fit for use. During
this latter period it may be well stirred up two or three times. The application
of this agent to the purification of saccharine matters is carried on as follows,
but the details may be varied:-Some of the saccharide of lead is to be worked
up with water to the consistence of cream, and passed through a fine sieve
into the "blow up" or other clarifying vessel. The raw sugar, with the neces-
sary quantity of water, is then to be added, and the whole mixed together,
when the steam or other heat is to be applied until the necessary temperature
is attained, which my experiments lead me to consider is two hundred and
twelve degrees of Fahrenheit, although it is possible that on the large scale a
lower heat, say, one hundred and eighty, may be found sufficient. The solu-
tion of sugar is now to be filtered through a "bag filter" or other suitable
filtering apparatus, and when perfectly transparent ("bright") is to be received
into a suitable cistern. In operating on cane juice, beetroot juice, &c., I would
advise the saccharide of lead to be substituted for the lime or carbonate of
lime at present used. When the necessary quantity of this agent has been

page_text: added, the juice is to be brought to the boil, and then filtered through a bag
filter or other suitable filtering apparatus. It is perhaps unnecessary for me
to observe, that the quantity of saccharide of lead to be used will depend upon
the quality of the raw material. A little experience will enable the operator
to ascertain the requisite proportion. I recommend that a trial should be
made, in the first instance, at the rate of forty pounds of dry litharge to one
ton of raw sugar of fair quality, and this proportion may afterwards be
increased or diminished with other quantities of the same sugar to suit the
manufacturer. As the impurities are more easily precipitated from cane juice,
&c. than from raw sugar, it may be advisable to use a smaller proportion of
saccharide of lead than is recommended above when operating on such saccha-
rine matters. After filtration it is necessary to remove a quantity of lead
which has got into solution in the bright liquor or juice. There are several
chemical agents, such as sulphuric acid, oxalic acid, hydro-sulphuric acid gas.
sulphurous acid gas, accidulated ferro-cyanide of potassium, phosphate of
lime, bin-oxalate of potassa, &c., which will render insoluble the lead. I,
however, give the preference to a certain mixture, which can be made in the
following manner:-Calcined bone, "bone earth," or "bone ash," in fine
powder is to be well washed by repeated affusions of boiling water. The bone
earth is then to be made into the consistence of thin paste, and two thirds of
its weight (when dry) of sulphuric acid previous diluted with four volumes of
water, is to be slowly incorporated with it. These materials are then to be
simmered for about twelve hours, frequent stirring being resorted to, and from
time to time a little water is to be added as it evaporates away. At the end
of this time as much water is to be added as will reduce the mixture to the
consistence of cream, when the whole is to be thrown into a conical linen bag
to separate the clear fluid, and the residuum washed till the water ceases to
taste acid. The strained fluids obtained as above, are then to be evaporated
to about half their bulk, and when cold are to be filtered, and the filtered
fluid is to be evaporated to dryness in a glass or other suitable vessel, and the
mass resulting therefrom is to be heated to a dull redness for an hour in a
platinum basin, and when cold is to be reduced to fine powder. This powder
is to be boiled with some water in a platinum or other suitable vessel for two
hours, constant stirring being employed, and water added from time to time as
it boils away, and then to be filtered, and the residuum to be washed with
boiling water till the water ceases to taste acid. The different fluids obtained
from the powder are then to be mixed together, and brought to the boil,
when a thin cream of lime is to be slowly added, stirring well at the same
time, and continuing the boiling until a slight opacity appears, when filtration

page_text: is to take place. The clear fluid (solution of phosphate of lime) now obtained
is to be slowly stirred into a weak (say, one part of soda and twenty parts
water) and boilings olution of carbonate of soda, until a very slight acidity is
produced. The white precipitate produced in the soda solution by the phos-
phate of lime is to be allowed to subside when the clear fluid is to be drawn
off and evaporated to the point at, which it: begins to shew chrystals, when
quite cold. It is then to be mixed with the white precipitate above men-
tioned. This mixture, for distinction sake, I shall call phosphate of soda
and lime; and though I consider it the best agent for rendering insoluble the
lead contained in the bright liquor or juice, I do not mean to confine myself
to its use.
I shall now describe the manner in which it may be applied.-I shall
suppose the bright liquor or juice to have been received. into a copper vessel
with a "steam jacket," and that the temperature of the fluid is about one hun-
dred and eighty degrees of Fahrenheit. Now.mix in gradually as much of
the phosphate of soda and lime as will render insoluble the lead. The liquor
or juice is now ready for filtration; but before this operation is performed it
will be necessary to determine positively that the whole of the lead has been
rendered insoluble. After it has been ascertained by testing, as is now well
understood, that the whole of the lead has been rendered insoluble, the liquor
or juice is to be filtered through a bag filter or other suitable filtering appa-
ratus for the purpose of removing the insoluble lead. The filtered liquor or
juice may now be transferred into the vacuum pan or other suitable evapo-
rating vessel, and at once converted into sugar; or, as a preliminary step to
this conversion, the liquor or juice may be filtered through beds of coarse-
grained charcoal in the manner now practised in many London refineries.
Before I conclude the description of this part of my Invention I think it
necessary to observe, first, that raw sugar may be used instead of.refined
sugar in the preparation of what I have called the saccharide of lead; second,
that the saccharide of lead may be made by other processes than the one de-
scribed by me, as, for example, by boiling together litharge, sugar, and water;
third, that the smooth paste mentioned in the early part of this Specification,
and which, for distinction sake, I shall call lead paste, is a powerful precipitator
of the impurities contained in saccharine matters; and fourth, that (although I
do not recommend them) hydrated oxide of lead and oxide of lead itself may
be employed for the purification of raw sugar, cane juice, &c. When the lead
paste is employed for precipitating the impurities from saccharine matters, it is
to be used in the manner described for the saccharide of lead. Like this agent
the details may be varied. The hydrated oxide of lead can be prepared by

page_text: dropping a weak solution of nitrate of lead (stirring well at the same time)
into a weak solution of caustic potassa, leaving the latter very slightly. in
excess, throwing the precipitate on a filter to drain, and afterwards washing it
with cold water for the purpose of carrying away the nitrate of potassia.
After being thus obtained, it may be used for the purification of saccharine
matters in the manner described for the saccharide of lead. Although oxide.
of lead has little or no effect on the impurities of raw sugar, when used in
the manner described for applying. the saccharide of lead; still it can be made
to act strongly on these foreign bodies, as, for example, by mixing together.
one part of finely-powdered litharge, twelve parts of water, and twenty-four
parts of raw sugar, and, evaporating these materials with constant stirring in a
water bath until they attain the consistency of a very thick syrup, when they
should be diluted with water to the density of thirty degrees of Beaumé's
saccharometer, at the temperature of one hundred and eighty, and then filtered;
A good liquor will thus be obtained.
I will now describe the second part of my Invention, which consists of a
mode or modes of preparing and using the basic acetates of lead, or other
combination of lead and acetic acid. To the lead paste, acetate of lead (or an
equivalent proportion of acetic acid) is to be added in the proportion of about
three parts of dry litharge to one part of acetate of lead, and these materials
are to be prepared and used in the manner before described for the prepara-
tion and use of the saccharide of lead, although the details may be varied.
These proportions give the highest basic acetate (hex acetate) known to
chemists; but I think it necessary to observe, first, that a still smaller propor-
tion of acetate of lead than above mentioned may be used; second, that the
grinding up together of these ingredients is not. indispensible, as an analogous
result may be produced by introducing separately into the liquor or juice the
lead paste and acetate of lead or acetic acid, as, for example, by putting into
the blow-up or other clarifying, vessel containing the raw sugar or juice..some
acetate of lead or acetic acid, and afterwards adding lead paste; third, that
hydrated oxide of lead may be substituted for the lead paste; and fourth, that
is not absolutely necessary to prepare either the lead paste or or hydrated
oxide of lead, as oxide of lead itself may be substituted for these bodies,
although not in my opinion with' advantage.
I will now describe the third part of my Invention, which consists of an
improved mode of rendering insoluble the lead contained in the bright liquor
or juice when the basic acetates of lead (subacetate of lead for example) have
been employed to purify the raw sugar cane juice, &c. The agent which I
prefer for this purpose is prepared in the same manner as the phosphate of

page_text: soda and lime mentioned in the first part of my Invention, with this difference,
that it is made slightly alkaline instead of slightly acid. This mixture, for
distinction sake, I shall call alkaline phosphate of soda and lime; and it is to
be used as follows, although the details may be varied :-I shall suppose the
bright liquor or juice to have been received into a copper vessel with a "steam
jacket," and that the temperature of the fluid is about one hundred and eighty
degrees of Fahrenheit. Now mix in gradually as much of the alkaline
phosphate of soda and lime as will render insoluble the lead. The liquor or
juice is now ready for filtration, but before this operation is performed it will
be necessary to determine positively that the whole of the lead has been
rendered insoluble. After it has been ascertained by testing, as is now well
understood, that the whole of the lead has been rendered insoluble, the liquor
or juice is to be filtered through a bag filter, or other suitable filtering appa-
ratus, for the purpose of removing the insoluble lead and afterwards the liquor
or juice may be converted into sugar.
Before I conclude the description of this part of my Invention, I think it
.necessary to observe, first, that the phosphate of soda and lime may be used
instead of the alkaline phosphate of soda and lime; second, that what I have
called the white precipitate, which is produced in preparing the above phos-
phates, may be used in a manner different from that directed by me, as, for
example, the clear fluids contained in these phosphates may be added to the
bright liquor or juice first, and the white precipitate afterwards; third, that
the above phosphates, instead of being made slightly acid and slightly alkaline,
may be made neutral; fourth, that ammonia or potassa may be substituted for
the soda contained in the above three phosphates; and fifth, that the phos-
phates of soda, potassa, or ammonia may be used as substitutes for the
phosphate of soda and lime, the alkaline phosphate of soda and lime, and
the neutral phosphate of soda and lime.
I will now describe the fourth part of my Invention, which consists of
improvements in the vacuum pan, as referred to in the Drawing. D, the
vacuum pan; B, the receiver; H, a pipe inserted into the bottom of the
receiver B, and thirty-four feet long. It is shewn broken in the Drawing.
This pipe dips into the small box R filled with water. A, the condenser; E,
the injection cock for the admission of cold water; C, the air pump; F, the
pipe of communication between the air pump and condenser; G, a pipe
inserted into the bottom of the condenser A. It is of the same length as the
pipe H, and dips into a similar box Q filled with water. The following
description will explain the mode of action:-Any liquor which boils out of
the vacuum pan D falls into the receiver B, and from thence down the pipe

page_text: H into the box R, from whence it flows away into some suitable receiver.
The steam from the liquor in the vacuum pan D passes into the receiver B;
and from thence into the condenser A where it meets the injection water
coming through the injection cock E, by which it is condensed, and falls to
the bottom of the condenser A, and passes from thence through the pipe G
into the vessel Q, from whence it runs away. As the whole of the steam
which is produced in the vacuum pan will be condensed by the means above
described, it must be obvious that nothing but the air contained in the liquor
or the air coming through leakages in the vacuum pan can pass through the
pipe of communication F into the air pump C. As there may be sugar houses
where there is not a sufficient height to enable these improvements to be
carried out in the manner shewn in the Drawing, the following substitutes
may be used: First, instead of the long pipes G and H, small pumps may be
applied in their places; second, the exhaust arm Z of the vacuum pan D may
be carried up such a height as will give the necessary elevation for the con-
denser A and the receiver B. For the purpose of preventing any condensation
in the exhaust arm Z, it might be incased in another pipe, between which
steam might be admitted. I am aware that it has been proposed to condense
the steam arising from the vacuum pan by injection water passing through a
pipe similar to the pipe G.
Now my improvements consist in the combination of the long pipes and the
air pump, or in the combination of the air pump and two small pumps used
in the manner described above.
Having thus explained my Invention, I wish it to be understood that I do
not claim generally the use of basic acetates of lead in the manufacture of
sugar, neither do I claim generally the separation of insoluble lead from
saccharine matters by filtration through bag or other filters, but what I
claim is,
First, the use and application of saccharide of lead, whether prepared in the
manner herein described or in any other manner, of lead paste, and of oxide
of lead in the manufacture of sugar, and the use and application of suitable
chemical agents for rendering insoluble the lead left in the bright liquor or
juice through the use and application of saccharide of lead, whether made in
the manner herein described, or in any other manner of lead paste and of
oxide of lead. And I also claim the use of bag or other filters for separating
insoluble lead contained in the bright liquor or juice when such lead has been
introduced through the use of hydrated oxide of lead.
Second, I claim the means herein described of preparing and using basic

page_text: acetates of lead, or other combinations, lead and acetic acid in the manufacture
of sugar.
Third, I claim the means herein described of rendering insoluble the lead
left in the bright liquor or juice when the basic acetates of lead have been
employed to purify the raw sugar, cane juice, &c. And I also claim the
separation of insoluble lead produced in the bright liquor or juice in the
manner herein described, by filtering the saccharine matters containing such
lead through bag or other filters.
Fourthly, I claim the improvements herein described in the combination
and working of vacuum pans.
In witness whereof, I, the said George Gwynne, have hereunto set my
hand and seal, this Twenty-seventh day of August, in the year of
our Lord One thousand eight hundred and fifty.