IMPROVEMENTS IN THE TREATMENT AND PURIFICATION OF SUGAR
Year: 1878

page_text: LETTERS PATENT to Jolin Frederick Cooko Farquhar and James Burns
Macfarlane, both of 24 and 25, Long Acre, in the County of Middlesex, for the
Invention of "IMPROVEMENTS IN THE TREATMENT AND PURIFICATION OF
SUGAR."
Sealed the 11th October 1878, and dated the 11th May 1878.
PROVISIONAL SPECIFICATION left by the said John Frederick Cooke
Farquhar and James Burns Macfarlane at the Office of the Commissioners of
Patents on the 11th May 1878.
JOHN FREDERICK COOKE FARQUHAR and JAMES BURNS MACFARLANE, both of 24
and 25, Long Acre, in the County of Middlesex. IMPROVEMENTS IN THE TREAT-
MENT AND PURIFICATION OF SUGAR."
This Invention has for its object improvements in the treatment and purification
of sugar.
To purify sugars we submit impure crystallized sugars, either as they come from
the crystallizing pans or after they have been roughly cleansed in centrifugal
machines or otherwise, to a current of steam and air under pressure for a short spaco
of time, by which the molasses with which the grains of sugar are coated is carried
off from the crystals, afterwards a current of air alone may be passed through the
sugar to dry it. To effect this the impure sugars are placed into a vessel with a
perforated false bottom, or it might be sides. Air under pressure, to which steam
has previously been admitted, is then allowed to enter the top of the vessel, and
passing through the mass of sugar carries the molasses away through the perforated
bottom. So soon as the moisture passing off from the sugar comes off clear, steam
is shut off and the air continued to be passed through the sugar until it is dried.
Instead of or before passing steam through the sugar, water might be carried
through, together with a stream of air.
In place of the air and steam being forced through the sugar it might be drawn.
through by a vacuum formed below the false bottom.

page_text: The sugar, after being cleansed as above described, may be compressed into a cake
or loaf by submitting the sugar, when nearly dry or somewhat heated, to a sudden
pressure of compressed air whilst it is still contained in the mould or vessel in
which it has been cleansed.
Bleaching matters may also, by means of the current of air and steam, be carried 5
into and amongst the sugar, and caused to act upon it.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Frederick Cooke Farquhar and James Burns Macfarlane in
the Great Seal Patent Office on the 11th November 1878.
JOHN FREDERICK COOKE FARQUHAR and JAMES BURNS MACFARLANE, both of 24
and 25, Long Acro, in the County of Middlesex. "IMPROVEMENTS IN THE TREAT-
MENT AND PURIFICATION OF SUGAR."
This Invention has for its object improvements in the treatment and purification
of sugar.
To purify sugars we submit impure crystallized sugars either as they come from
the crystallizing pans or after they have been roughly cleansed in centrifugal
machines or otherwise to a current of steam and air under pressure for a short space
of time, by which the molasses with which the grains of sugar are coated is carried
off from the crystals, afterwards a current of air alone, by preferenco in a somewhat
heated state, is passed through the sugar to dry it. To effect the purification of
impure dry crystallized sugars we place the impure sugars into a vessel with a
perforated false bottom, or it might be sides. Air under pressure, to which steam
has previously been admitted, is then allowed to enter the top of the vessel, and
passes in the form of a warm moist mist or vapour through the mass of sugar, and
carries the molasses away through the perforated bottom. So soon as the moisture
passing off from the sugar comes off of the color or clearness desired steam is shut
off and the air continued to be passed through the sugar until it is dried.
The sugar, after being cleansed as above described, may be compressed into a cake
or loaf by submitting the sugar, when nearly dry and somewhat heated, to a sudden
pressure of compressed air whilst it is still contained in the mould or vessel in
which it has been cleansed, or else in a separate mould.
Bleaching matters may also, by means of the current of air and steam, be carried
into and amongst the sugar, and caused to act upon it.
In order that sugars may readily and quickly be treated, as above described, we
form the apparatus by which the process is to be carried out in such a manner that
the vessels in which the sugar is contained when under treatment can readily bo
opened and closed, and readily moved from place to place.
To allow of the vessels being quickly opened and closed we make the top and
bottom covers of the vessel loose, and when the vessel is closed hold them in place
by pressure obtained by a screw or by hydraulic or other power; and to allow of
the vessels being readily moved from place to place we mount the moveable bottom

page_text: upon a truck which can be run to and fro along rails. An apparatus arranged in
this manner is shown in the Drawings hereunto annexed.
Figure 1 is a vertical section and Figure 2 a plan view of the apparatus.
A is a vessel made with solid sidos and open at top and bottom; this we place on
to an elastic ring B surrounding a horizontal bed of wiro gauge C or other perforated
bed, which forms part of a moveable truck D. Within the vessel A is a conical
inner receptacle E into which is filled the sugar to be treated. When the sugar has
been filled into the receptacle E it is covered over at the top by a loose cover F
which rests upon projections on the top of the receptacle, so that there is an open
space left all around the cover between it and the receptacle. When the impure
sugars have been filled into the inner vessel E the truck is run along rails G to
bring it to the place where the cleansing operation is to be carried on. Here the
truck comes above a table H, which can be lifted by turning a nut I on a screw J,
or by hydraulic or other power. The truck is readily stopped in the correct position
by a spring catch X, as shown at Figures 6. As the table is raised it comes against
the bottom of the frame of the truck, and lifts the truck together with the vessel A
upon it until the top of the vessel is forced against an elastic ring K on the under side
of a metal chamber L. The bottom of the métal chamber thus serves as a cover for
the vessel A, and a steam-tight joint is formed between then as the elastic ring K
becomes compressed by the rising of the table. The chamber Lis, as shown, carried
by uprights from the bed M, the screw stem J by which the table H is carried passes
down through the centre of this bed, and the nut I rests on the top of the bed,
which thus serves as an abutment for the nut to bear against.
A plan view and vertical section of the chamber L are shown separately at
Figures 3 and 4.
Steam under pressure can be admitted to the chamber through the pipo N, and
air under pressure by the pipe O. In front of the ends of each of these pipes where
they enter the chamber is a vertical plate or partition P for the steam or air to
impinge against as they enter the chamber in order to disperse them. The exit
from the chamber is through a pipe Q which rises up from the centro of the bottom
nearly to the top of the chamber; the upper end of this pipe is also surrounded by
a cylindrical guard, as shown, which prevents a direct passage of air or steam from
the vessel to the pipe, but leaves open a circuitous passage. This servos to prevent
any water that may be condensed in the vessel from passing out by the pipe Q.
Any water that may become condensed in the vessel can be drawn off from time to
time through a pipe provided for the purpose.
When a vessel A has been charged with impure sugar and has been brought under
the chamber L, and into the position shown at Figuro 2, air under pressure, say of
about 20 lbs. or upwards to the square inch, is by the opening of a cock admitted to
the chamber L; steam under a similar or slightly greater pressure is also adınitted,
the amount of steam admitted being regulated by the steam-cock.
The chamber L is provided with a thermometer by which the temperature within
the chamber is indicated.
We prefer to admit sufficient steam to the chamber to bring the air within it to a
temperature of about 120° to 130° Fahrenheit. The temperature should not be
raised beyond 180° or 190° Fahrenheit, or the sugars would probably be injured.
Although wo have mentioned 20 lbs. to the square inch as the pressure at which
the steam and air may be used, yet we prefer to work at a pressure of from 40 to
50 lbs. to the inch, or with a still higher pressure. Advantageous results may,
however, in some cases be obtained when using a lesser pressure. The mixed air
and steam pass from the chamber L through the pipe Q into the vessel A, and to
the sugar contained in the inner receptacle E.
-
Any condensed water which may enter the vessel A is prevented from passing on
to the sugar by the loose cover with which the inner vessel E is covered.
.. Any water accumulating in the vessel A may from time to time be drawn off by
a cock at the bottom.

page_text: After a short time a dirty stream of dissolved molasses issues from the perforated
false bottom C on to the table H, from which it flows off by a spout H¹. When the
escaping liquid comes off of the color desired the steam-cock is closed and com-
pressed air alone is passed into the chamber L, and from there through the sugar.
The air becomes somewhat heated in the chamber and capable of quickly taking up
moisture; the sugar is therefore rapidly dried, and thus the crystals of sugar may
be obtained in a more or less purified or in a perfectly pure state as may be desired,
and without being in any way injured or the beauty of the crystal being destroyed.
When the sugar has been dried or sufficiently dried, which will be almost imme-
diately, the supply of compressed air is shut off from the chamber, the table H is
lowered until the wheels of the truck again rest upon the rails, and the truck is
then run off to the place where the vessel A is to be emptied, whilst another truck
containing a fresh charge of impure sugar can be run on to the table H; thus the
operation of cleansing sugar from impurities can be carried on with great rapidity.
In some cases it is desirable, after washing the crystals of sugar by submitting
them to a stream of combined steam and air under pressure, to further cleanse them
by the action of cleansing liquids or by passing very pure syrups over them. To
allow of this being done there is a pipe R passed down through the centre of the
chamber L, through which the cleansing liquor or the syrup can be supplied on to
the sugar in the chamber after that the cover of the inner vessel has been removed.
When the vessel A has been closed by being pressed up to the chamber L after that
the cover has been removed from the inner vessel, the liquor or syrup with which
the sugar is to be treated is supplied on to the top of the sugar through the pipe R.
A cock on this pipe is then closed and the liquor or syrup can be forced to
percolate through the sugar by then admitting compressed air to the chamber L, and
BO to the vessel A.
In some cases it is desirable that the sugars in the inner receptacle of the vessel A
should be submitted to the action of air or steam and air under pressure for a time
before allowing the air or steam to escape through them; in this case there may be
on the truck below the perforated plate Ca solid cover S, as shown at Figure 5,
with an outlet pipe leading from it fitted with a tap. When the tap is closed the
sugars in the inner receptacle of the vessel A may for a time be submitted to the
action of steam and air under pressure without allowing them to pass in a stream
through the sugars; the tap may then be opened and the steam and air allowed to
escape and carry off the impurities as before explained.
If it is desired to form the sugar into a loaf, cake, or cakes, the sugar, after being
partially dried in the vessel A as before explained, may have the stream of com-
pressed air shut off from it for a time, and when the sugar is still warm again
submit it suddenly to pressure by quickly opening the air-cock; or the sugar, after
being cleansed in the purifying vessel, may be transferred into a mould, and there be
pressed into a loaf or cake by compressed air mixed with a slight quantity of steam
to enable the crystals to adhere together.
Having thus described the nature of our Invention, and the manner of performing
the same, we would state that we lay no claim to the treatment of impure sugars by
the drawing through them by the aid of a vacuum of dry or moist air not under
pressure, as we believe that experiments have before been made to cleanse sugars in
this manner; no sufficient beneficial result is, however, found to be derived from
treating them in this manner; what we claim is,-
First. The treatment and purification of impure crystallized sugars by passing
through them a stream of steam together with air under pressure, substantially as
herein-before described.
Second. The treatment and purification of impure crystallized sugars by passing
through them a stream of steam together with air under pressure, and afterwards a
stream of compressed air alone, substantially as herein-before described.
Third. The manufacture of loaf or cake sugar, substantially as herein-before
described.

page_text: Fourth. The combined arrangement of apparatus by which the process heroin-
before described of treating and purifying sugars can be carried on expeditiously.
In witness whereof, we, the said John Frederick Cooke Farquhar and James
Burns Macfarlane, have hereunto set our hands and seals, this Ninth day
of November, in the year of our Lord One thousand eight hundred and
seventy-eight
J. F. C. FARQUHAR. (L.B.)
J. B. MACFARLANE. (L.B.)