CERTAIN IMPROVEMENTS IN THE PROCESS OF BOILING AND REFINING SUGAR
Year: 1818

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DANIEL
WILSON, of Earl Street, London, Gentleman, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Third day of February,
in the fifty-eighth year of His reign, give and grant unto me, the said Daniel
Wilson, my exors, adñors, and assigns, His special licence, full power, sole
privilege and authority, that I, the said Daniel Wilson, my exors, admors,
and assigns, should and lawfully might, during the term of years therein
mentioned, make, use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies and
Plantations abroad, my Invention of "CERTAIN IMPROVEMENTS IN THE PROCESS
OF BOILING AND REFINING SUGAR;" in which said Letters Pattent there is con-
tained a proviso that if I, the said Daniel Wilson, shall not particularly
describe and ascertain 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, and cause the same to be inrolled in His Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said Letters Patent, that then the said Letters Patent, and all liberties
and advantages whatsoever thereby granted, shall utterly cease, determine,
and become void, as in and by the same, relation being thereunto had, may
more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Daniel Wilson, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are particularly described
and ascertained in and by the following description thereof, that is to say :-
The expressed juice of the sugar cane contains in solution, together with the
saccharine matter, a variety of other substances which impede the cristallisation
of the sugar, and, by partially adhering to it, render it impure. It is chiefly
owing to this mixture of foreign ingredients that the cane juice possesses so
great a tendency to run into acidity, for they operate as an artificial ferment,
and the portion which adheres to the raw sugar continues to act in a similar
manner, as it is well known that a solution of raw sugar is much more liable
to run into acidity than a sirup of the same strength made from that which
has been refined. It therefore becomes an object of importance, as well in the
manufacture of raw sugar in the Colonies as in its refining, to ascertain the
nature of those hurtful ingredients, and by chemical means to effect their
separation without injury to the saccharine grain. I do not consider it
necessary for the description of my Invention to enter here upon the general
composition of cane juice or raw sugar, but will confine my remarks to those
substances which are peculiarly injurious, and the separation of which I effect.
The juice of the cane and a solution of raw sugar contain two sorts of impu-
rities, the one chemical and the other mechanical, (that is to say,) the latter
being merely floating particles of bruised cane held suspended in the fluid. It
is possible to effect their separation by a mechanical operation, and by such it
is usually done; but the formerly being actually dissolved and in intimate
union, can only be extracted by a chemical action; and it is to those impu-
rities, for which no means of separation has yet been devised, that this part of
my Invention relates. And this I accomplish by the addition of certain sub-
stances hereafter to be described, which combine with the chemical impurities
of the cane juice or raw sugar, form with them an insoluble compound, thereby
reducing them to the state of mechanical impurities, which it is possible to
separate by means of filtration. The one which is the most abundant of these
chemical impurities approaches in its nature to what is called by chemists
extractive matter; the others are tannin and gallic acid, which I have dis-
covered to exist in cane juice and raw sugar. These substances possess the
property of forming insoluble compounds with the salts and oxides of tin and
zine; and this part of my Invention consists in the addition of a certain
portion of those ingredients to the cane juice or saccharine liquor in refining,
thereby improving the colour and facilitating the cristallisation of the sugar.
The solutions of tin or zinc in any of the acids possess the property of coagu-

page_text: lating these impurities, but I prefer such as contain the sulphuric acid, on
account of its forming an insoluble compound with lime, which enables it to be
entirely separated from the liquor along with the oxide, in combination with
the extract tannin and gallic acid. And I further prefer for this purpose the
solution of zinc in sulphuric acid, which constitutes what is called the sulphate
of zinc. And in order that the method of using it may be fully understood, I
will here describe the operation. Firstly, in the refining of sugar; and,
secondly, in the manufacture from the cane. In the former process the pan is
to be charged with strong line water, and the sugar added to it in the usual
manner, and the fire set; for every hundredweight of sugar used a solution
is to be made of four ounces of sulphate of juice in as small a quantity of
water as it will conveniently dissolve. When the sugar in the pan is entirely
melted, the solution of the sulphate of zinc is to be added, and the whole well
stirred. A mutual decomposition will then take place; the oxide of zinc will
combine with the extract tannin and gallic acid & render them insoluble, and
the sulphuric acid will be neutralized and precipitated in the form of sulphate
of lime by the lime of the water, so that nothing whatever of the sulphatic of
zinc remains in solution. There is in the lime water employed for dissolving
the sugar a quantity of lime more than sufficient to neutralise the sulphuric
acid of the sulphate of zinc; but when the raw sugar employed contains much
acid, and a strong grain is required, I take one ounce of lime in powder for
every four ounces of sulphate of zinc, and add to it a sufficient quantity of water
to form what is called a milk of lime, and this I mix well with the sugar in the
pan in about five minutes after the addition of the solution of zinc. One of the
principal advantages of the use of these ingredients is, that by rendering inso-
luble the large quantity of vegitable matter which the solution of sugar contains,
they deprive it of much of its viscidity, and render it capable of rapid filtration,
so that the liquor may be made perfectly bright without the use of blood; the
quantity of scum is therby much decreased, and the tendency to putrification
which the animal matter imparts to the sirup is equally avoided. These ingre-
dients are employed with much advantage in the refining of sugar in conjunction
with the filtering apparatus for which Mr. John Sutherland lately obtained
His Majesty's Letters Patent. When this apparatus is used, the solution
of sugar, after being treated in the manner already described, is brought to the
boiling point, run through the filter, which renders it perfectly bright, and
afterwards boiled to a proof. This is the method of using the sulphate of.
zinc, but in cases where the use of lime water or lime in substance is excep-
tionable, I previouly precipitate the oxide of zinc and use it in that stato
This oxide may be prepared by decomposing any of the salts of zinc with

page_text: potash, soda, or lime, but it is of consequence that it should be minutely
divided, and I prefer making it by the following process:-Prepare a quantity
of lime water and gradually add to it a solution of sulphate of zinc as long
as it occasions any precipitate; when it ceases to do this allow the insoluble
matter to fall down and draw off the water; then add more fresh lime water.
and again the sulphate of zinc until you have decomposed as much as you
want. Care must be taken not to continue to add the sulphate of zinc after.it
¡ceases to occasion a precipitate; this will be known by the addition of lime
water making it turbid, or by its ceasing to brown turmeric paper. I use the
same proportions in this case as in the other, employing the precipitated oxide
of four ounces of sulphate of zinc to each hundredweight of sugar, and add it
in the pan precisely in the same manner, mixing the whole thoroughly; it is
likewise heated to the boiling point, and may be filtered with the same facility.
In the manufacture of sugar, in the Colonies, for every hundred gallons of cane
juice eight ounces of sulphate of zinc should be used, and the sooner it is
added to the juice the better, and the common temper of lime may be employed
in a few minutes after it. The quantity of this temper should be oncreased
at the rate of two ounces of lime to the hundred gallons of juice, in order to
-saturate the acid of the sulphate of zinc, but the experience of the boiler will
soon enable him properly to apportion this. A method of purifying cane juice
by rapid filtration has always been extremely desirable, and the apparatus
already alluded to, assisted by the action of these ingredients, completely sepa-
rates every floating particle, so that the quality of the sugar is greatly
improved. The cane juice, after the addition of the sulphate of zinc and
temper, should be brought nearly to the boiling point in the clarifier, and then
run through the filter into the teaches to be boiled. In the manufacture of
raw sugar, where an excess of lime always should exist in the liquor, the
sulphate of zinc is most advantageously used, but the oxide may be also
employed after being prepared in the manner already described, and in the
same proportions. That which has been specified with regard to the sulpbate
and oxide of zinc also applies to the solutions and oxides of tin, and more
particularly to the sulphate; but I claim generally the application of the
solutions and oxides of tin and zinc to the abstraction of colouring matter and
soluble impurities from cane juice and solutions of sugar, thereby improving
the colour, lessening the viscidity, and rendering them capable of being readily
purified by filtration. In the boiling and refining of sugar it is of the first
importance that the evaporation should be rapid, without the danger of burning
or decomposing the saccharine matter; and in order to accomplish this I
obtained His Majesty's Letters Patent for Certain Improvements in the

page_text: Process of Boiling and Refining Sngar, dated January 23d, 1817. The
method consists in applying the heat necessary for the boiling or evaporation:
of the sugar by means of a current of the heated fluid which passes under
and round the sides of the pan containing the sugar to be so boiled.. or
evaporated, and the fluids which are thus used for conveying the heat are
whale, spermacete, cod, seal, herring, pilchard, or any other fish oil, linseed,
rape, liemp, olive, nut, palm, sunflower sced, poppy seeds, and castor oils,
tallow, lard, butter, grease, animal fat, and wax. The pans in which the sugar
is boiled consists of two metallic vessels, one within the other, with a small
space between them. They are placed without any fire under them, and the
outer pan communicates by means of pipes or tubes with a boiler or vessel
in which the medium or fluid for conveying the heat is heated; and the
evaporation is carried on by a current of heated oil or fatty matter being
forced by means of a pump from the boiler in which it is heated into the space
between the two pans, from whence it flows back into the boiler to be reheated,
as is fully described in the Specification of the said Patent, duly inrolled in
His Majesty's High Court of Chancery. In this apparatus, as therein
described, the surface by which heat can be conveyed from the oil or fatty
medium is limited to the area of the inner pan, and in some cases a more rapid
evaporation is required. The improvement which I have made in this appa-
ratus, and which I herein specify or describe, consists in applying the heated
medium in pipes or tubes, which are surrounded by the liquor to be heated or
evaporated, so that by encreasing the quantity of pipe or tube any extent of
heating surface may be obtained, and the rapidity of evaporation will be
increased in the same ratio. In this improved apparatus the sugar is contained
in a single pan, on the bottom of the inside of which a coil of pipe is placed,
and this pipe communicates at both ends with the boiler in which the medium
is heated, having a force pump attached to one of them in such a manner that
by working it the heated oil will be driven through the coil of pipe, which
being entirely surrounded with the liquor to be evaporated, the heat from the
medium will rapidly be absorbed, and it will pass by the other end of the pipe
at a lower temperature to the boiler, to be again supplied with heat. In this
manner, by enlarging the surface of pipe, the rapidity of evaporation may be
greatly increased, without any danger of injuring the sugar. I prefer wrought
iron for the boiler in which the medium is heated, and copper tinned, or pure
tin, for the pipes through which it circulates.
In witness whereof, I, the said Daniel Wilson, have hereunto set
my hand and seal, this First day of August, in the year of our
Lord One thousand eight hundred and eighteen.
DANIEL (L.s.) WILSON.

page_text: AND BE IT REMEMBERED, that on the First day of August, in the
year of our Lord 1818, the aforesaid Daniel Wilson came before our said
Lord the King in His Chancery, and acknowledged the Specification aforesaid,
and all and every thing therein contained and specified, in form above written.
And also the Specification aforesaid was stamped according to the tenor of
the Statute made for that purpose.