IMPROVEMENTS IN THE TREATMENT OF ANIMAL CHARCOAL AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1867

page_text: LETTERS PATENT to John Stenhouse, of 17, Rodney Street, Pentonville,
in the County of Middlesex, Chemist, and James Duncan, of Clyde
Wharf, West Ham, in the County of Essex, Sugar Refiner, for the
Invention of "IMPROVEMENTS IN THE TREATMENT OF ANIMAL CHARCOAL AND
IN THE APPARATUS EMPLOYED THEREIN."
PROVISIONAL SPECIFICATION left by the said John Stenhouse and
James Duncan at the Office of the Commissioners of Patents, with their
Petition, on the 21st May 1867.
We, JOHN STENHOUSE, of 17, Rodney Street, Pentonville, in the County of
Middlesex, Chemist, and JAMES DUNCAN, of Clyde Wharf, West Ham, in the
County of Essex, Sugar Refiner, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE TREATMENT OF ANIMAL CHARCOAL AND IN
THE APPARATUS EMPLOYED THEREIN," to be as follows:-
When animal charcoal has been employed to decolorize syrups or saccharine
solutions, as is well known, it gradually absorbs lime and other earthy or
alkaline substances, by which its decolorizing and absorbent powers are
diminished.
Our Invention has for its object the more effectual cleansing of this charcoal
preparatory to its re-use.
In carrying out our Invention we take a quantity of this used charcoal and
wash it well with boiling water, and then introduce it into a suitable tank or

page_text: cistern containing hot water slightly acidulated with nitric acid. The quantity
of nitric acid used should not be more than sufficient to neutralize the lime
and other earthy or alkaline substances present in the charcoal, as if an
excess of the acid were employed it would dissolve out a portion of the
phosphate of lime, and thus injure the texture of the charcoal. It is necessary
to ascertain by a preliminary experiment on a small scale the quantity of acid
required in each case to neutralize the lime and other basic substances present
in the charcoal since their amount varies exceedingly. When the charcoal
and acid solution have been digested for half an hour to one hour, which is
best effected by blowing steam into the mixture, the saline solution consisting
chiefly of nitrate of lime is removed, and the charcoal repeatedly washed with
either hot or cold water as is most convenient until all soluble impurities
are removed. When dry it is ready to be reburned and is again fit for use.
The process just described can also be advantageously applied to new animal
charcoal before it has been used in sugar refining, as it removes impurities
naturally present in the charcoal which diminish its decolorizing and absorbent
properties.
The tank we propose to employ in the washing process above described
is made of wood, slate, or any other material not acted upon by the dilute
acid, the bottom of which is contracted, and the sides being made to slope
downwards, whilst the necessary water is introduced under pressure from the
bottom, the water so introduced passes thoroughly through and over the
separate pieces of charcoal, and effects the washing operation in a very effective
manner. A drainer is arranged at the bottom so as to readily take off the
water when the tank is emptied, and pipes are arranged at any convenient
part of the sides through which the water can flow off when it attains to their
height.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Stenhouse and James Duncan in the Great Seal Patent
Office on the 15th November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
STENHOUSE, of 17, Rodney Street, Pentonville, in the County of Middlesex,
Chemist, and JAMES DUNCAN, of Clyde Wharf, West Ham, in the County of
Essex, Sugar Refiner, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of May, in the year of our Lord

page_text: One thousand eight hundred and sixty-seven, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said John Stenhouse and James Duncan, Her special license that we, the
said John Stenhouse and James Duncan, our executors, administrators, and
assigns, or such others as we, the said John Stenhouse and James Duncan,
our executors, administrators, or assigns, should at any time agree with,
and no others, from time to time and at 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 "IMPROVEMENTS IN THE TREATMENT
OF ANIMAL CHARCOAL AND IN THE APPARATUS EMPLOYED THEREIN," upon the
condition (amongst others) that we, the said John Stenhouse, and James
Duncan, by an instrument in writing under our 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 cause the same to be
filed in the Great Seal Patent Office within six calender months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said John Stenhouse and James Duncan, do
hereby declare the nature of our said Invention, and in what manner, the
same is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say:-
When animal charcoal has been employed to decolorize syrups or saccharine
solutions, as is well known, it gradually absorbs lime and other earthy or
alkaline substances, by which its decolorising and absorbent powers are
diminished.
Our Invention has for its object the more effectual cleansing of this charcoal
preparatory to its re-use.
In carrying out our Invention we take a quantity of this used charcoal and
wash it well with boiling water, and then introduce it into a suitable tank or
cistern containing. hot water slightly acidulated with nitric acid. The quantity
of nitric acid used should not be more than sufficient to neutralise the lime and
other earthy or alkaline substances present in the charcoal, as if an excess of
the acid were employed it would dissolve out a portion of the phosphate of
lime, and thus injure the texture of the charcoal.. It is necessary to ascertain
by a preliminary experiment on a small scale the quantity of acid required in
each case to neutralise the lime and other basic substances present in the
charcoal since their amount varies considerably. When the charcoal and acid
solution have been digested from half an hour to one hour, which is best

page_text: effected by blowing steam into the mixture, the saline solution consisting
chiefly of nitrate of lime is removed, and the charcoal repeatedly washed
with either hot or cold water, as is most convenient, until all soluble im-
purities are removed. When dry it is ready to be reburned and is again fit
for use.
The process just described can also be advantageously applied to new animal
charcoal before it has been used in sugar refining, as it removes impurities
naturally present in the charcoal which diminish its discolorising and absorbent
properties.
The tank we propose to employ in washing the charcoal is most advan-
tageously made of a circular form with the sides sloping inwards towards
the bottom. At convenient beights in the sides are pipes through which the
water can be admitted or drawn off, these can be closed by plugs or stop-cocks
made of wood or earthenware or any other suitable material not acted upon
by the dilute acid. The water employed for washing out the charcoal is
introduced under pressure near the bottom through openings for that purpose,
so that it thoroughly permeates the charcoal and washes out the impurities
present, the water flowing out through other pipes situate near the top. After
the charcoal has been sufficiently washed it is withdrawn from the tank through
a flap door at the bottom.
We prefer to construct the above described tank of wood, but slate,
earthenware, or any other material not acted upon by the dilute nitric acid
may be employed.
And in order that our said Invention may be fully understood we shall now
proceed more particularly to describe the same, and for that purpose shall refer
to the several Figures on the annexed Sheet of Drawings, the same letters of
reference indicating corresponding parts in all the Figures.
Figure 1 of our Drawings represents a sectional elevation of the tank and
fittings which we propose to employ in washing animal charcoal; Figure 2
is a corresponding plan of the same; and Figure 3 is a side elevation showing
the bottom of the tank open for the discharge of its contents.
A is the tank or vessel for holding the charcoal to be treated, it may be
constructed of wood or other suitable material and of any required form, and
is provided with sloping sides, as shown in our Drawings. In the sides of
this tank and situate near the bottom thereof are fitted a series of cocks B, B,
for the admission of steam or water under pressure; near the upper edge of
the tank there is provided an overflow pipe C for the escape of the washings,
and beneath this there is a pipe and plug D for drawing off any excess of water
from the surface of the charcoal, the level of which whilst under treatment is

page_text: represented by the dotted line E; a flap door F is hinged to the bottom of the
tank and secured by any convenient fastening a for the purpose of discharging
the charcoal after it has been cleansed.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried
into effect, we would observe in conclusion that what we consider to be novel and
original, and therefore claim as the Invention secured to us by the herein-
before in part recited Letters Patent is,-
First, the peculiar mode of and apparatus for cleaning animal charcoal, as
herein-before described and illustrated by the Drawings annexed.
Second, the application and use to and in the cleaning of animal charcoal
of water acidulated with nitric acid as herein-before described.
In witness whereof, I, the said John Stenhouse on behalf of myself,
and the said James Duncan, have to this our Specification set my hand
and seal, the Fifteenth day of November, One thousand eight hundred
and sixty-seven.
JOHN STENHOUSE. (L.S.)