IMPROVEMENTS IN RE- VOLVING RETORTS FOR THE MANUFACTURE AND RE-BURNING OF ANIMAL CHARCOAL
Year: 1868

page_text: LETTERS PATENT to John Fletcher, of Bow, in the County of
Middlesex, Engineer, for the Invention of "IMPROVEMENTS IN RE-
VOLVING RETORTS FOR THE MANUFACTURE AND RE-BURNING OF ANIMAL
CHARCOAL."
PROVISIONAL SPECIFICATION left by the said John Fletcher at the
Office of the Commissioners of Patents, with his Petition, on the
23rd May 1868.
I, JOHN FLETCHER, of Bow, in the County of Middlesex, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN REVOLVING RETORTS FOR THE MANUFACTURE AND RE-BURNING OF ANIMAL
CHARCOAL," to be as follows, that is to say :-
My Invention consists in an improved arrangement of fittings for
the inside of revolving retorts by which the charcoal is more exten-
sively distributed over the internal surface, the increased surface with
which the charcoal is thus brought in contact greatly facilitating the
process.

page_text: My improved arrangement consists of one or more flat bars or plates
of cast iron or other suitable metal of the same or nearly the same
length as and suitably fixed to the inside of the retort. One side of
each bar or plate is provided with a series of projecting pieces pitched
at equal distances apart throughout its whole length, and at right angles
to the edge of the bar or plate, and angled or inclined in the direction
of the length of the bar or plate. The bars or plates are each pro-
vided with a longitudinal flange fixed to or formed on one of their
edges, and of the same height as the projecting pieces to which it is
also fixed. The bars or plates are fixed in the inside of the retort
longitudinally, the flanged edge of each bar or plate coming near the
inner surface of the retort so as to leave a small space between them,
and the other edge of each bar comes near the centre of the retort.
As the retort revolves the aforesaid bars or plates gather up a portion
of the charcoal with which the retort is charged, and retain the same
until it arrives at a certain elevation (which varies according to the
angle at which the bars or plates are placed) when it falls down,
and in its descent is distributed over the surface of the retort. The
projecting pieces on the bars or plates serve to propel the charcoal
from the charging end to the discharging end of the retort; for this
purpose the projecting pieces are placed at an angle in the direction
that the charcoal has to travel, videlicet, the lower parts or bases of
the projecting pieces being nearer to the discharge end of the retort,
and the upper parts being nearer to the feeding end of the same.
projecting pieces enter into the charcoal, and advance it towards the
discharge end of the retort. The distance of the advance and the
quantity of charcoal carried forward varies according to the angle and
height of the projecting pieces. When more than one bar or plate is
employed they are pitched at equal distances from each other, and at
such an angle that the charcoal in its descent from the upper bar or
plate shall fall upon the back side of one of the succeeding bars or
plates which will conduct it to the opposite side of the retort, by which
means an aggregate amount of heating surface will be brought in
direct contact with the charcoal under treatment.
These
For the purpose of discharging the charcoal affer it arrives at the
discharge end of the retort I attach a scoop or bucket to the end plate
of the retort (which plate is fixed to or forms part of the retort and
revolves with it), and which end plate is also fitted with a discharge
nozzle in its centre round which the retort revolves. This nozzle is

page_text: of a circular form at the part where it fits into the end plate, and of
a rectangular or other suitable form outside the end plate where it
extends downwards. The part of the nozzle which projects into the
inside of the retort forms a cup or receiver, into which the charcoal
raised by the scoop or bucket falls and passes down through the nozzle
into the retort below it, and if this be the lowest retort thence into
the cooler or receiver. More than one scoop or bucket may be used,
in which case the buckets may be smaller, the size varying according
to the number employed. I can make the retort conical instead of
cylindrical, and so avoid the use of the projecting pieces on the flat
bars or plates, for as the largest end would be the discharge end (the
retort being placed horizontally on its centre line) the charcoal
would naturally fall as the retort revolved to the lowest and largest
end.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Fletcher in the Great Seal Patent Office.
on the 23rd November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN.
FLETCHER, of Bow, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of May, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Fletcher, Her special licence that I,
the said John Fletcher, my executors, administrators, and assigns, or
such others as I, the said John Fletcher, my executors, administrators,
and 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 REVOLVING RETORTS
FOR THE MANUFACTURE AND RE-BURNING OF ANIMAL CHARCOAL," upon the
condition (amongst others) that I, the said John Fletcher, my executors
or administrators, by an instrument in writing under my, or their,
or one of their hands and seals, should particularly describe and

page_text: 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 calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Fletcher, do hereby declare
the nature of my 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 Drawing hereto
annexed, and to the figures and letters marked thereon, that is to
say :-
My Invention consists in an improved arrangement of fittings for the
interior of revolving retorts by which the charcoal operated upon is more
extensively and more equally distributed over the surface of the retort
than by the present arrangements of fittings in retorts, the increased
heating surface with which the charcoal is brought in contact greatly
facilitating the process. The discharge of the materials from the retort is
also effected in a more convenient manner than by the apparatus hitherto
used. The shape of the retort instead of being made cylindrical is
sometimes made conical so as to facilitate the passage of the materials.
To make my Invention better understood I will proceed to describe
the same by reference to the accompanying Drawing, in which the same
letters refer to similar parts in all the Figures.
Figure 1 represents a longitudinal section of a pair of revolving retorts
with my improved arrangement of fittings and discharge scoops or
buckets and hoppers; Figure 2, a horizontal section on line A, B,
Figure 1, of the upper retort; Figure 3, cross section of same on
line C, D, of Figure 2; and Figures 4 and 5, end views of the retorts
shewing the feeding and discharge nozzles or hoppers and the gearing
for working the retorts.
The improved arrangement of fittings shewn in Figures 1, 2, and 3
consists of two longitudinal flat bars or plates B, B, (more than two
bars or only one may be employed) of cast iron or other suitable material
of nearly the same length as and fixed at a short distance from the
sides of the retort A by means of cross pieces so as to leave a space
between their outer edges and the inner sides of the retort. One side
of each of the bars B, B, is fitted or cast with a series of projecting
pieces C, C, pitched at equal distances apart through the whole length

page_text: of the bars and at right angles to their edges. These projecting pieces
are inclined in the direction of the length of the bars or plates B, B,
their lower parts being nearer the discharge end and their upper parts
nearer the feeding end of the retort, and serve to propel the charcoal
under treatment. The bars B, B, are each provided with a longitudinal
flange D, D, of the same height as the projecting pieces and fixed to
or formed on one of their edges the nearest to the side of the retort; so
as to leave a space between the flanged edge of the bar and the retort
for the passage of the charcoal, the other edge of each bar being near
the centre of the retort. The bars B, B, are fixed at equal distances
from each other and at an angle such that when the retort revolves the
bars B, B, alternately take up a portion of the charcoal (which enters
the retort at E) and retain it until they rise to an elevation such as will
cause it to fall by its own weight (which elevation varies according to
the angle at which the bars are placed) on to the back of the other bar,
when it will be distributed over the surface of the retort. At the same
time the projecting pieces enter the charcoal and carry it forward to the
discharge end F, when it is discharged through the hopper I into the
retort beneath, or into the cooler or receiver, as the case may be.
The distance to which the charcoal is advanced and the quantity
advanced varies according to the angle and height of the projecting
pieces. For the purpose of discharging the charcoal after it has been
brought to the discharge end of the retort I fix scoops or buckets G,
Figures 1 and 2, to the end plate H, Figure 1, of each of the retorts;
one scoop only or more than two may be employed. The plate H is
fixed to or forms part of the retort and revolves with it; it is fitted
in its centre with a discharge nozzle or hopper I, Figure 1, round which
the retort turns. This nozzle or hopper consists of a cup or receiver i
projecting into the retort, and of a circular form where it fits into the
end plate at j, and of a pipe J of a rectangular form outside the end
plate. The charcoal taken up by the scoops or buckets G falls into
the
cup i, then passes down through the pipe J into the retort below it,
or if this be the lowest retort into the cooler or receiver.
The improved arrangement of fittings may be applied to retorts or
cylinders already constructed.
I can make the retorts of a conical form instead of cylindrical and
thus avoid the use of the projecting pieces C, C, on the flat bars B, B.
The retort is placed horizontally on its centre line, and in its rotation

page_text: the charcoal will fall by its own weight towards the largest end, which
will be the discharge end of the retort.
Having now described the nature of the said Invention, and the
manner of performing the same, what I claim is,-
Firstly. The improved arrangement and combination of internal
fittings for revolving retorts, whereby the charcoal is more extensively
and equally distributed over the heating surface of the retort than by
known arrangements, substantially in the manner and for the purposes
herein-before described and represented in Figures 1, 2, and 3 of the
accompanying Drawing.
Secondly. The peculiar construction and the application to retorts of
one or more scoops or buckets and discharge nozzle or hopper in com-
bination, substantially in the manner and for the purposes hercin-before
described and represented in Figures 1, 2, 4, and 5 of the accompanying
Drawing.
Thirdly. The making and use of retorts of a conical form as herein-
before described.
In witness whercof, I, the said John Fletcher, have hereto set
my hand and scal, this Twenty-third day of November, in the
year of our Lord One thousand eight hundred and sixty-
cight.
Witness,
W. A. GILBEE.
JOHN FLETCHER. (L.S.)