AN IMPROVEMENT IN REFINING SUGAR
Year: 1863

page_text: LETTERS PATENT to Phineas Cowan, of the Firm of L. Cowan and Sons,
of Barnes, in the County of Surrey, Manufacturers, for the Invention of
"AN IMPROVEMENT IN REFINING SUGAR."
Sealed the 4th March 1864, and dated the 17th September 1863.
PROVISIONAL SPECIFICATION left by the said Phineas Cowan at the
Office of the Commissioners of Patents, with his Petition, on the 17th
September 1863.
I, PHINEAS COWAN, of the Firm of L. Cowan and Sons, of Barnes, in the
County of Surrey, Manufacturers, do hereby declare the nature of the said
Invention for "AN IMPROVEMENT IN REPINING SUGAR," to be as follows:-
My Invention relates to that stage of the process of refining sugar in which
the sugar in a diluted condition, or in a state of liquor or of syrup, is passed
through animal charcoal for the purpose of being purified or decolorized.
Heretofore in the ordinary arrangement, when pressure is not employed, the
air contained in the charcoal cistern impedes the descent of the saccharine
liquor, so that considerable time is lost before the charcoal is sufficiently
saturated, and special skill is required to control the operation, and the
presence of air in the charcoal after saturation or "covering" renders the
washing thereof troublesome and protracted. Moreover in those ordinary
arrangements in which steam or other artificial pressure is employed to force
the liquor down through the charcoal considerable danger is involved and
comparatively costly apparatus required.

page_text: Now my Invention has for its object to remedy these disadvantages. For
this purpose instead of the first-mentioned method in which pressure is not
used, and instead also of the employment of the ordinary pressure cisterns and
apparatus for forcing the liquor through the charcoal by steam or other
artificial pressure, I exhaust or partially exhaust the air from the cistern or
vessel containing the charcoal by an air pump or other means of exhaustion
applied at the lower or other convenient part of the cistern or vessel so as to
produce a vacuum or partial vacuum where required, in such manner that the
air being thus removed from the body of the charcoal the sugar, liquor, or
syrup will descend by gravitation aided by the ordinary pressure of the
atmosphere on its upper surface, and as it will meet no resistance from air
in the charcoal it will percolate the latter quickly, and uniformly saturate it
with rapidity and facility and without, the danger involved in the use of
mechanical or artificial means of pressure from above.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Phineas Cowan in the Great Seal Patent Office on the
17th March 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PHINEAS
COWAN, of the Firm of L. Cowan and Sons, of Barnes, in the County of
Surrey, Manufacturers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of September, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Phineas Cowan, Her special licence that I, the
said Phineas Cowan, my executors, administrators, and assigns, or such
others as I, the said Phineas Cowan, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time
and all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "AN IMPROVEMENT IN REFINING SUGAR," upon the condition
(amongst others) that I, the said Phineas Cowan, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and

page_text: cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Phineas Cowan, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
My Invention relates to that stage of the process of refining sugar, in
which the sugar in a diluted condition, or in a state of syrup or liquor, is
passed through animal charcoal for the purpose of being purified or decolorized.
Heretofore there have been two known methods of performing this operation,
in one of which the syrup percolates the charcoal by natural gravitation, no
artificial pressure being employed to force it down; in the other steam or
other artificial pressure is applied at the top of the charcoal, cistern, or vessel,
to drive the liquor or syrup through the charcoal. In both these arrangements
the air contained in the charcoal and charcoal cistern impedes the descent of
the saccharine liquor, so that considerable time is lost before the charcoal is
sufficiently saturated, and special skill is required to control the operation.
Moreover the presence of air in the charcoal after the saturation, or as it is
technically called the "covering" or "settling" operation renders the
subsequent "washing" protracted. Also in those ordinary arrangements in
which steam or other artificial pressure is employed to force the liquor
through the charcoal, considerable danger is involved and comparatively costly
apparatus is required.
Now my Invention has for its object to remedy these disadvantages. For
this purpose according to my Invention, instead of the first-mentioned method
in which pressure is not used, and instead of the second-mentioned method in
which the liquor is forced through the charcoal by steam or other artificial
pressure from the top, I exhaust or partially exhaust the air from the cistern
or vessel containing the charcoal, so as to produce a vacuum or partial
vacuum therein, the air being thus removed from the body of the charcoal,
the sugar, liquor, or syrup will descend by gravitation, aided by the ordinary
pressure of the atmosphere on its upper surface, and as the descending liquor
will meet no resistance from air in the charcoal, it will percolate the latter
quickly and uniformly and saturate it with rapidity and facility, and without
the danger involved in the use of mechanical or artificial means of pressure
from above.
The method which I adopt for carrying my Invention into effect is as
follows:-Before proceeding to exhaust the air, as above described, I admit

page_text: sufficient syrup or saccharine liquor into the cistern or vessel to cover the
upper surface of the charcoal contained therein, and I thereby prevent air
from being drawn into or through the charcoal from above it, when the
exhausting operation is afterwards applied. I then pump the air from and
around the charcoal, whereupon the saccharine liquor or syrup will descend
and will saturate the charcoal with regularity, pass down through it with
rapidity, and present itself at the bottom bright and clear.
Apparatus for performing the Invention may be constructed by combining
or connecting a common air pump with a charcoal cistern or vessel of the
description ordinarily used for the saturating or as it is technically called the
"settling" or "covering" process in sugar refining, such air pump and cistern
being combined in the way usually adopted for combining air pumps with
vessels to be exhausted by them. I recommend that, the air pump should
communicate with the charcoal cistern through the ordinary outflow orifice at
the lower part of the latter. The cistern which I recommend is an ordinary
open cistern having as usual a supply pipe. and outflow cock, and a false
After the cistern
'bottom covered with flannel or other filtering material.
is charged with charcoal and the outflow cock closed, I admit the saccharine
liquor or syrup into the cistern, so that it may completely cover the upper
surface of the charcoal; I then open the outflow cock and work the air pump
and extract the air from the charcoal, and from around the grains or particles
thereof, the layer of liquor at top preventing air from being drawn from above
into and through the charcoal, and from thereby disturbing the same and
interfering with the proper conduct of the operation. I keep up the feed of
syrup or liquor into the cistern as usual, maintaining the influx or supply
equal to the quantity absorbed by or drawn into the charcoal, thereby
preserving the upper surface of the charcoal from exposure to the air through-
out the operation. The ordinary atmospheric pressure operates on the upper
surface of the liquor which will descend and duly saturate the charcoal. When
this operation is completed the liquor may be allowed to subside, or it may be
drawn off into any vessel ready for its reception.
Although my Invention can be adopted with full advantage when open or
uncovered cisterns are employed, it can also be applied with equal facility to
closed or covered cisterns, as when such apparatus are used there will be an
atmospheric pressure sufficient, for the purpose of this Invention, upon the
surface of the reservoir or feed vessel which supplies and communicates with
the cistern.
Having now described the nature of my said Invention, and in what
manner the same may be performed, I declare that I claim as my improve-

page_text: ment in refining sugar, promoting the "settling" "covering" or saturating of
the charcoal by exhausting or partially exhausting the air from the charcoal
and charcoal cistern or vessel, substantially as described.
In witness whereof, I, the said Phineas Cowan, have hereunto set my
hand and seal, this Sixteenth day of March, One thousand eight
hundred and sixty-four.
Witness,
M. HENRY,
Patent Agent,
84, Fleet Street,
London.
PHINEAS COWAN. (L.S.)