IMPROVEMENTS IN MECHANICAL RETORTS
Year: 1884

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I, JAMES MOSS BENNETT, of Glasgow, in the county of Lanark, Metallurgist,
do hereby declare the nature of my said Invention for IMPROVEMENTS IN
MECHANICAL RETORTS," to be as follows:-,
This Invention consists of improvements in the construction of mechanical
retorts to be employed in effecting the distillation and carbonisation of such
matters as sawdust, shavings, tan bark and the like, the destructive distillation of
shale, dross, and other carbonaceous or oleaginous materials, for revivifying spent
char and for drying dessicating or roasting substances of animal, vegetable, or
mineral origin.
The improved retort consists of a series of shallow cylindrical casings or covered
trays of cast iron or other material, laid horizontally and superposed one over
another to from a tier, the individual casings being separated by spaces which form
a flue or flues for the passage of the flame or hot gases from a furnace.
An opening
is formed through the axial line of the casings through which freely passes a
vertical rotating shaft, and in the space between each casing a short pipe or tube
is cast on each casing and fitted to enclose the shaft, such tubes, extending from
the upper side of each casing to the bottom of the next in order above it, and
being tightly fitted to prevent access of air from the flue spaces. These tubular
pieces also serve as a central pillar or support for the casings. The casings are
connected in pairs at alternato sides, by ducts which are cast or fitted on to the
casings, and which serve to convey from casing to casing the sawdust or other
material treated within them. On the vertical shaft passing through the casings
are fitted a series of horizontal arms extending radially outwards from the part of
the shaft within each casing, and on these arms are fitted inclined stirring blades
which are so disposed that the layer of material lying on the bottom of the tray
formed by each casing is stirred up, shifted about from side to side and again
evenly laid and distributed over the bottom, while a continuous, but comparatively
slow feeding forward of the material takes place, towards the ducts which serve to
convey it into the succeeding casing below. The material is fed in continuously
or intermittently through a suitably trapped hopper over the uppermost casing of
the series, and after carbonisation or similar treatment, is withdrawn from the
lowest casing by a pipe or duct which may be trapped or otherwise arranged to
prevent the admission of air to the casings. The tier of casings is enclosed by

page_text: brickwork in which suitable spaces are left for the admission of the flame or
furnace gases employed to heat the material within the casings, and for connecting
the spaces between the casings in the form of a zig-zag flue or flues these spaces
being by preference divided by a wall or setting of brickwork to support the
casings and to divide the flue. One, two, or more of the lower casings may be
fitted below the inlet from the furnace to the flues, or may be closed off from the
action of heat, and their contents cooled by circulation of cold air or of water
round the casings in ordor that the char which is drawn off from the lowest casing
may not burn when exposed to the air. Opposite the ducts connecting the casings,
or at any other convenient part of the casings, openings are made to communicato
with a main pipe which leads off the gaseous or volatile products of distillation to
a condensor or condensers, the withdrawal of such products being aided if desired
by the action of an exhauster. This pipe is by preference formed in sections, so
that by removal of a single section, access may be had to the interior of any one
or any pair of the casings at the outlets for the gaseous products. Such access
may however be provided by means of doors formed in the sides of the casings,
the doors being only of such size and so placed as to admit of fitting and removing
or repairing the radial arms on the rotating shaft, and of periodic cleaning out of
the casings.
The incondensible gases evolved in the treatment of the material within the
retort are by preference led into the flue spaces and therein consumed.
Instead of applying the heat of a furnace for effecting the carbonisation of the
material within the retorts, heated air or steam may be employed, in either of
which cases it may be advantageous to form the trays with double casings or
jackets for the hot air or steam. When the retort is employed for effecting the
distillation of shale or other material, means may also be provided for admitting
super-heated steam into one or more of the casings.

page_text: I, JAMES MOSS BENNETT, of Glasgow in the County of Lanark, Metallurgist do
hereby declare the nature of my Invention for "IMPROVEMENTS IN MECHANICAL
RETORTS; and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
"
This Invention consists of improvements in the construction of mechanical
retorts to be employed in effecting the distillation and carbonisation of such
matters as sawdust, shavings, tan bark and the like, the destructive distillation of
shale, dross, and other carbonaceous or oleaginous materials for revivifying spent
char, and for drying dessicating or roasting substances of animal, vegetable, or
mineral origin.
In the accompanying Drawings, Figure 1 is a vertical section.
plan, and Figure 3 is a horizontal section of my improved retort.
horizontal section of a modified form,
Figure 2 is a
Figure 4 is a
The improved retort consists of a series of shallow cylindrical casings or covered
trays of cast iron or other material laid horizontally and superposed one over
another to form a tier, the individual casings being separated by spaces which form
a flue or flues B for the passago of the flame or hot gases from a furnace. An
opening is formed through the axial line of the casings A through which freely
passes a vertical rotating shaft C, and in the space between each casing a short
pipe or tube a is cast on each casing and fitted to enclose the shaft, such tubes
extending from the upper side of each casing to the bottom of the next in order
above it or vice versa, and being tightly fitted to prevent access of air from the flue
spacos B. These tubular pieces a also serve as a central pillar or support for the
casings. The casings are connected in pairs at alternate sides, by ducts which are
cast or fitted on to the casings A, and which serve to convey from casing to casing
the sawdust or other material treated within them. On the vertical shaft O
passing through the casings are fitted a series of horizontal arms E extending
radially outwards from the part of the shaft within each casing, and on these arms
are fitted inclined stirring blades e which are so disposed that the layer of material
lying on the bottom of the tray formed by each casing A is stirred up, shifted
about from side to side and again evenly laid and distributed over the bottom,
while a continuous but comparatively slow feeding forward of the material takes
place, towards the ducts D which serve to convey it into the succeeding casing
below. The material is fod in continuously or intermittently through a suitably
trapped hopper F over the uppermost casing of the series, and after carbonisation
or similar treatment, is withdrawn from the lowest casing by a pipe or duct G,
which may be trapped or otherwise arranged to prevent the admission of air to the
casings.
The tier of casings A is enclosed by brickwork H in which suitable spaces are
left for the admission of the flame or furnace gases employed to heat the material
within the casings, and for connecting the flue spaces B between the casings, in the
form of a zig-zag flue or flues, these spaces being by preference divided by a wall
or setting of brickwork to support the casings and to divide the flue, One, two,

page_text: or more of the lower casings A may be fitted below the inlet from the furnace to
the flues, or may be closed off from the action of heat, and their contents cooled by
circulation of cold air or of water round the casings, in order that the char which is
drawn off from the lowest casing may not burn when exposed to the air. Opposito
the ducts connecting the casings, or at any other convenient part of the casings,
openings are made to communicate with a main pipe I which leads off the gaseous
or volatile products of distillation to a condenser or condensers, the withdrawal of
such products being aided if desired by the action of an exhauster. This pipe I is
by preference formed in sections, so that by removal of a single section, access may
be had to the interior of any one or any pair of the casings at the outlets for tho
gaseous products. Such access may however be provided by means of doors J
formed in the sides of the casings, the door being only of such size and so placed as
to admit of fitting and removing or repairing the radial arms E on the rotating
shaft, and of periodic cleaning out of the casings.
The incondensible gases evolved in the treatment of the material within the
retort, are by preference led into the fluo spaces and therein consumed.
In the example illustrated in Figure 4, the ducts D through which the material
in process of being charred, are arranged alternately at the edge, and at the centre
of the trays or casings, so that in its course through the retort, it is slowly fed
forward from the centre to the circumference of the one tray, and from the
circumference to the centre of the next tray in succession.
Instead of applying the heat of a furnace for effecting the carbonisation of the
material within the retorts, heated air or steam may be employed, in either of
which cases it may be advantageous to form the trays A with double casings or
jackets for the hot air or steam. When the retort is employed for effecting the
distillation of shale or other material, means may also be provided for admitting
superheated steam into one or more of the casings A.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First. The combination of parts forming the improved mechanical retort herein
described and illustrated.
Second. A mechanical retort formed of a series of hollow casings superposed in a
tier, and provided with means for feeding forward the material subjected to
distillation within them, flue spaces or jackets being formed between the casings,
substantially as herein set forth.