IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF MACHINERY OR APPARATUS FOR SUPPLYING COAL, CANNEL, OR OTHER SUBSTANCES TO RETORTS OR OVENS, AND FOR WITHDRAWING THE SAME AFTER DISTILLATION; ALBO IMPROVEMENTS IN RETORTS, RETORT CHAMBERS, MOUTH PIECES, DOORS, COVERS, OR LIDS."
Year: 1868

page_text: ETTERS PATENT to James Dunbar, of. 49, Vicarage Road, Camber-
well, S.E., Engineer, and Richard Nicholson, of Dulwich, S.E.,
Gentleman, both in the County of Surrey, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF MACHINERY
OR APPARATUS FOR SUPPLYING COAL, CANNEL, OR OTHER SUBSTANCES TO
RETORTS OR OVENS, AND FOR WITHDRAWING THE SAME AFTER DISTILLATION;
ALBO IMPROVEMENTS IN RETORTS, RETORT CHAMBERS, MOUTH PIECES, DOORS,
COVERS, OR LIDS."
PROVISIONAL SPECIFICATION left by the said James Dunbar and
Richard Nicholson at the Office of the Commissioners of l'atents,
with their Petition, on the 6th April 1868.
We, JAMES DUNBAR, of 49, Vicarage Road, Camberwell, S.E.,
Engineer, and RICHARD NICHOLSON, of Dulwich, S.E., Gentleman,
both in the County of Surrey, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT
OF MACHINERY ON APPARATUS FOR SUPPLYING COAL, CANNEL, OR OTHER
Pic 81

page_text: SUBSTANCES TO RETORTS OR OVENS, AND
DISTILLATION; ALSO IMPROVEMENTS IN
FOR WITHDRAWING
THE SAME AFTER
RETORTS, RETORT CHAMBERS, MOUTH
PIECES, DOORS, COVEES, оя LIDS," to be as follows:-
Our Invention relates first to improvements in the construction
and arrangement of machinery or apparatus for the purpose of
inserting and depositing coal, cannel, or other substances into retorts
or ovens and for withdrawing the same after distillation. For this
purpose we employ an overhead framework carried upon wheels and
travelling (in front of retort benches or settings) upon rails or girders,
which are supported on iron brackets, columns, or any other convenient
mode. The framework consists of cradles, wheels, and beams or
girders which span the distance between rails and over or under the
cradles. These beams carry another cradle or cradles borne upon
wheels and arranged to travel transversely, bearing the scoops, rakes,
rams, or combined scoops, rakes, and rams. (What we mean by this
combination is, that the scoops contain the rakes or claws within
them and attached to same. The parts forming the rakes and claws
may be made in various ways, the scoops also to act as
rams for
forcing out instead of withdrawing the residue or coke). We some-
times use two or more scoops placed side by side instead of a large
one; by this plan we ensure a more even spread of the coal.
The
scoops after being inserted with the coal or cannel are turned upside
down by hand or machinery, thereby depositing their contents within
and upon the bottom of retorts. One or more scoops or rakes or a
combination may be mounted on a framework as described, but
supported by one or more arms radiating from a centre, whereby it
is adapted to retorts on any level. Instead of scoops we sometimes
use a tray or trays supported similar to the scoops but do not require
to be turned over, the bottoms being made in two or more pieces
attached by hinges or other mode, so that they may drop down or
otherwise open to deposit their contents.
These improvements also relate to machinery, which may be
constructed to travel upon the retort house floor instead of overhead.
We sometimes use a framework (for carrying the scoops, rakes, or
rams, or combination of them) constructed to travel upon rails secured
on top of brickwork, which forms the retort benches or settings.
The main girders to extend beyond a sufficient distance to carry the
machinery for supporting and working of the scoops, rakes, rams, o

page_text: Instead of rails supported on top of brickwork we
over retort
In
a combination.
may construct a travelling framework which strides
benches or settings, the rails being laid on floor of retort house; or,
where inconvenient to stride the benches or settings we lay one line
of rails on floor and one over mouth pieces of retorts. The machinery,
for working the travellers, scoops, rakes, rams, or a combination may
be by hand, steam, or hot-air engine, or other motive power.
some cases the traversers carrying the motive power with them or
otherwise by a stationary engine or other motive power giving motion
to a line or lines of shafting carried upon suitable bearings along
the sides or tops of retort houses or in front of benches or settings;
To
this shafting to be fitted with drums of suitable dimensions.
communicate motion from the aforesaid shaft or shafting to the
traversers or cradles which carry the scoops, rakes, rams, or a combi-
nation, we employ an arm attached to the gearing and radiating
from a shaft on traverser; this arm is fitted with a frictional drum
at end; this drum remains stationary until brought in contact with
the drums on main line of shafting (which continues in motion).
Instead of drums frictional gearing, discs, or any other suitable
contrivance may be used.
Another mode we employ for working the scoops, rakes, rams, or
a combination is by affixing a steam engine and boiler or engine
alone attached to the framework, connected to and moving with the
said cradle, which carries the scoops, rakes, rams, or combination.
Where it is inconvenient to have the boiler travel with the machinery
we employ a stationary boiler, which may be placed in any convenient
situation to supply the necessary steam which is to be conveyed in
pipes laid throughout the building or buildings, such pipes to he
fitted with stop valves, flanges, or other junctions at intervals, and
from which the steam may be taken through flexible or other pipes
to the engine or engines on traversers. Machinery constructed on the
above principle would be well adapted to a circular plan of retort
settings. For inserting coal into the retorts we use also endless
travelling bands of chain, sheet steel, or other material, and actuated
on by suitable gearing; these bands travel under a hopper or hoppers
(fitted with crushing rolls or other mode of reducing the large lumps
to a suitable size) or other mode of supplying the coal on the bands.
These bands work over sheaves, pullies, or wheels, supported by one
or more arms and extending the whole length into retorts or as far

page_text: as may be required. The bands and arms carrying the same are
firstly inserted into the empty retort, and as the band travels carry-
ing with it the coal and depositing it at the extreme end, so the
bands are gradually withdrawn until the whole bottom of retort is
covered. For withdrawing the coke we use common or pitch chains
with suitable spikes or rakes attached thereto, or a combination with
sheet bands. For supplying coal or cannel into scoops we provide. a
travelling tender or tenders with an elevator and shoots on one or
both sides acting as measures and fitted with quadrant sides, which
may be opened by any convenient mode. These tenders run upon
rails on retort house floor or as described for the traversers carrying
the scoop, rake, and ram machinery.
Our Invention relates secondly to improvements in chambers, doors,
and other fittings in connection with retort mouths and mouth pieces.
Our improvement consists in the construction of a wrought or
cast iron chamber with one or more retorts opening into the same.
These chambers are made with rings or ribs bolted or otherwise
attached to the back of the chamber and projecting to a suitable
distance to encircle and support ends of retorts. In cases where more
than one retort opens into the chamber we continue rings extending
outwards to face of box or chamber, such rings being bent or made
to the form and dimensions of the interior of retorts, making in fact
a continuation of the retorts themselves. The faces of these rims are
made true and level with the flange of main chamber. The whole
of the retorts and chamber to be closed by means of one door made
true and fitted to form a perfect joint between the projecting ends
and flanges of retorts and chamber. The continuation of the retorts
in and through the chamber are of iron and constituting part of the
chamber which have openings formed in the top, sides, or any other
place to allow the escape of the generated gas into the chamber, the
chamber being wider than the retorts, allowing the gas to escape
round and up the sides through a socket to ascension pipe and
hydraulic main. The main door which closes the chamber and
retorts (where more than one is used) is fitted with extra doors or
cover plates forming an opening through the main door and corres-
ponding with the ends of retorts in said chamber.
Another object of our Invention is to dispense with plates or iron
framing usually adopted to support the ends of retorts or chambers,

page_text: Our chambers are constructed with rings which encircle and support
the ends of retorts, the chamber itself being supported in the brick-
work or by a girder or other support to its under side. This improve-
ment also applies to chambers constructed without the extension of
the retorts through the same. In the flanges which form the joints
between retort ends, chamber, and doors, we form a groove, grooves, or
channel, which may be filled with felt luting or other composition,
the doors having corresponding grooves or channels, and which are
secured to flanges of chamber by any convenient mode. Chanibers
may also be constructed in brickwork with iron framing and plates
to which doors may be applied made of iron, or an iron framework
filled in with fire-bricks or composition.
Another form of chamber is a vertical cylindrical iron casing with
projecting sockets to carry ends of retorts, this casing to have openings
on the outside opposite to and corresponding with those of the retorts.
Inside this casing we place a second cylinder which forms a door,
and may be made to turn round, slide upwards or downwards. Instead
of internal cylinders we use a door or doors similar to those described
for the other chambers; these as well as the above chambers may
be placed horizontally.
Our improvements also relate to applying small doors to existing
D or other shaped retort mouth pieces. We make a framework in
iron of size and dimensions to fit over and be secured to existing
mouth pieces. When applied to D-shaped retorts we make the face
of framework to a circular form, this face having a projecting ring or
rib which is turned and forms a cone surface. The door to same
may be of cast or wrought iron and bored to fit the said mouth piece
on frame, or a groove may be made, and larger so as to allow of
luting or other composition being put into same. The door instead
of closing outside of cone may form a conical plug for end of
mouth piece. In some cases a groove or grooves may be turned on
the face of the cone of door, mouth piece, or both, and filled in with
any composition, luting, or metallic rings. Or, a channel may be
formed on a flat surface without being made conical, the door having
a projection to fit the same; these doors may be supported by
means of hinges or other mode and secured by any suitable means.
The framing of door to have lugs to carry a hinge or arm which.
supports the circular door at its centre. The door having two or

page_text: more bars attached to same and the ends projecting beyond the rim
or edge. The framing of door to have corresponding pieces according
to the number of arms on the door, so that when the door is closed
it is turned on its centre until the ends of the bars pass underneath,
and are clipped by the projecting inclined pieces on the frame.
SPECIFICATION filed in pursuance of the conditions of the Letters
Patent and of an Order of the Lord Chancellor by the said
James Dunbar and Richard Nicholson in the Great Seal Patent
Office on the 29th October 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
DUNBAR, of 47, Vicarage Road, Camberwell, S.E., Engineer, and
RICHARD NICHOLSON, of Dulwich, S.E., Gentleman, both in the County
of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of April, 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 us, the said James Dunbar and Richard
Nicholson, Her special license that we, the said James Dunbar and
Richard Nicholson, our executors, administrators, and assigns, or such
others as we, the said James Dunbar and Richard Nicholson, our
executors, administrators, or 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 "IMPROVEMENTS
IN THE CONSTRUCTION AND ARRANGEMENT OF MACHINERY OR APPARATUS FOR
SUPPLYING COAL, CANNEL, OR OTHER SUBSTANCES TO RETORTS OR OVENS, AND
FOR WITHDRAWING THE SAME AFTER DISTILLATION; ALSO IMPROVEMENTS IN
RETORTS, RETORT CHAMBERS, MOUTH PIECES, DOORS, COVERS, OR LIDS," upon
the condition (amongst others) that we, the said James Dunbar and
Richard Nicholson, our executors or administrators, by an instrument

page_text: same was to be performed, and cause the same to be filed in the
Great Seal Patent Office on or before the Twenty-ninth day of
October One thousand eight hundred and sixty-eight.
NOW KNOW YE, that we, the said James Dunbar and Richard
Nicholson, 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:-
Our said Invention relates,-
Firstly. To certain peculiar constructions, arrangements, and com-
binations of machinery or apparatus for feeding or introducing coal or
other like substances into gas retorts or ovens, and for withdrawing or
removing the same after distillation.
Secondly. To certain peculiar constructions and arrangements of the
doors and door fittings of gas retorts, whereby existing retorts. are
rendered better adapted for being supplied with coal or other gas-
producing material by our combined feeding and withdrawing apparatus.
Thirdly. To a peculiar arrangement of the mouths of gas retorts,
whereby any one or more of a bench or group of retorts may be opened
for cleaning or repairs without stopping the working of the rest or
causing loss or waste of gas therefrom.
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 corresponding Figures.
Figure 1 of our Drawings represents an end elevation looking in
the direction of the retorts) of one arrangement of our combined
apparatus for charging gas retorts and withdrawing the charges there-
from; and Figure 2 is a corresponding side elevation of the same,
looking longitudinally along the retort house.
A, A, are columns supporting two parallel overhead rails B, B, which
extend longitudinally along the retort house and parallel to the range
of retort mouths.
These rails B, B, support the traveller C, which is

page_text: provided with running wheels D, D, running along the longitudinal
rails B; E, E, are other running wheels mounted on a carriage or
cradle F, and running transversely to the rails B along the traveller C.
It will thus be seen that the cradle may be moved horizontally towards
or from the mouths of the retorts, and may be brought opposite to any
retort in the series. The traveller carries a grooved pulley or chain
wheel G, over which an endless rope or chain G 1 is passed for the
purpose of rotating the same. On the spindle of this chain wheel or
pulley there is keyed a spur pinion H, which gears with a spur wheel I
fast on the axis of one of the running wheels D of the traveller, thereby
imparting motion thereto. The movement of the cradle F along the
rails of the traveller is effected by means of the winch handle K. On
rotating this handle motion is imparted to an endless chain or band L,
which passes round the pulley M on the axis of the handle and over
a larger pulley N on the axle O of one of the running wheels E of
the cradle, and consequently transmits a travelling motion thereto in
either direction along the rails of the traveller. From the cradle or
carriage F are suspended the wrought-iron frames P, P'; which support
the combined scoop and rake Q, a portion only of which is shown in
Figure 2.
This combined scoop and rake which for the sake of brevity is
herein-after referred to as the " scoop" simply), is shown detached in
plan at Figure 3, and in transverse section in various positions and in
different forms of retorts at Figures 4, 5, 6, 7, 8, and 9 (herein-after
more fully referred to). The outer end of the scoop or that which is
furthest from the retorts is made cylindrical, as shown clearly in
Figure 2, and this cylindrical portion forms the journal for the rotation
of the scoop on its longitudinal axis, as herein-after explained. R, R,
are radial lever arms provided with bearings S, S, at their lower
ends for embracing and supporting the cylindrical portion of the scoop.
These arms are keyed on to the rocking shaft T carried in bearings U
in the lower end of the suspended frames P. The said rocking shaft
carries a worm wheel V, into which gears the worm W on the worm
shaft X actuated by the hand wheel Y. The attendant in charge of the
machine stands on the travelling platform Z, and by manoeuvering the
endless chain G, or the winch handle K, or the hand wheel Y, as may
be required, produces all the movements requisite for introducing and
withdrawing the scoop into and from the retort, and transporting it
either in a horizontal or a vertical direction from one retort to another,

page_text: On rotating the endless screw or worm W, the rocking shaft T rotates
partially, by which means the radial lever arms R, R, will be brought
to different positions, as shown by the dotted lines in Figure 1, thus
raising the scoop to the height of any one of the retorts in the
"bench."
"
In order to maintain the upper surface of the scoop perfectly horizontal
during this movement we propose to employ any simple form of parallel
motion, and we find that the desired result may be readily obtained by
the aid of an endless chain a (shown in detail in Figures 10 and 11),
passing over two equal sized chain pullies b and c, the one being
stationary and keyed or secured to the bearing U and the other c fitted
loosely upon the cylindrical part of the "scoop Q, but coupled there-
with by the intervention of the well-known arrangement of detent and
ratchet wheel. The object of the detent and ratchet arrangement is
to enable the scoop to be reversed or turned over in its bearings S, S,
for the purpose of discharging the coal into the retort (without
interference from the chain wheel c) after it has been introduced into
such retort, whilst the detent serves to couple the chain wheel c with the
Scoop when imparting the necessary parallel motion to the scoop for
keeping its
open side upwards or horizontal.
.
With the feeding scoop Q we in most cases combine one or more
moveable blades or series of moveable blades, rakes, or hoes d, d, shown
clearly in the details, Figures 3 to 9 inclusively. These hoes are
intended to answer the purpose of the discharging rakes or appliances
heretofore employed for withdrawing the charges from gas retorts, and
by combining such hoes with the feeding scoop we are enabled to
perform by the one combined apparatus the two operations of feeding
the retorts and withdrawing the charge, which operations have here-
tofore always been performed by the aid of separate and distinct
instruments or appliances. Two or more of these hoes d are keyed on to
two parallel rocking shafts e, e, disposed longitudinally in bearings fitted
inside the scoop Q, as shown in Figures 3, 5, 6, 8, and 9. Or, if preferred
one rocking shaft e and series of hoes d may be combined with the
scoop, as shown in Figures 4 and 7. In the former arrangement the
hoes & may be rather smaller than in the latter case, as will be seen
on referring to the Drawings. These hoes may be of various forms
according to the shape of the retort, as shown in the transverse sectional
views, and when not in action the hoes lie transversely across, the scoop

page_text: are
being enclosed within the hollow or trough thereof, as will be clearly
seen on referring to Figures 6, 7, and 9, which illustrate the position of
the scoop and its combined hoes d when filled with coal for feeding
the retort f. Before this operation, however, it is necessary to withdraw
the coke or residual products of the destructive distillation, for which
purpose the combined scoop is introduced in an inverted position into
the retort, the hoes being well within the hollow of the scoop, so as
to pass freely over the surface of the coke until the scoop has entered a
sufficient distance therein. In this position the rocking shaft e or the
pair of rocking shafts, as the case may be, are partially rotated in their
bearings by the action of the hand wheel g and gearing h (Figures 1, 2,
and 3), fast on the outer ends of the rocking shafts, when two
used, thereby causing each hoe d to describe an arc of a circle in a
downward direction so as to cut transversely across the mass of caked
fuel or coke in the retort from side to side thereof at each point where
a hoe or pair of hoes d occur, the hoes assuming the position shown
in Figures 4, and S. In this condition the scoop is withdrawn from
the retort by running back the cradle F, and the entire contents of the
retort will be drawn out with it at one single stroke or traverse, leaving
the retort ready for a fresh charge. The hand wheel g is now turned
in the reverse direction, which has the effect of turning the blades
or hoes inside the scoop again, and by continuing to act upon the same
hand wheel the rotation of the scoop in its bearings will be accomplished.
If desired, bevil wheel or other suitable gearing may be employed for
turning the scoop, but in single scoop machines we find it convenient
to apply hand power direct, as above described. We do not confine
ourselves to any particular mode of reversing the scoop.
Figures 4, 5, and 7 show the combined scoop and hoes adapted to a
circular retort, and Figures 7, 8, and 9, illustrate somewhat similar
scoops and lioes adapted to D retorts. In some cases we propose to
use a pair of combined scoops and hoes or rakes for supplying one
retort, as shewn at Q', Q', in Figure 7, whereby a more even spreading
of the coal over the bottoms of wide retorts will be effected. We also
sometimes propose to push out the coke from the retort by using the
end of the entering scoop as a ram, the coke being expelled through
one end of the retorts whilst the coal is introduced at the other end.
The scoops are supplied with coal either by manual labor or from a
travelling tender i (Figure 1), which consists of a coal box or bunker
suspended from a frame mounted on running wheels,, which

page_text: traverse the longitudinal rails B, B, in company with the traveller C,
so as to be always in readiness for filling the scoops; m is a discharge
spout at the lower portion of the tender, and n is a door hinged at the
top and worked by a worm wheel o and worm p, the latter being fast
on the upright shaft q, which is provided with a hand wheel r for
The
effecting the opening and closing of the door n, as required.
scoop to be filled from the tender is brought into the position shewn
at S in Figure 1, so that the coals may be shovelled by an attendant
inside the tender through the spout m directly into the scoop. The
tender may be kept supplied either by self-acting means, as for
example, by an elevator s, as shewn in Figure 1, or by manual labor.
The elevator if employed may be driven by any convenient prime mover
used for maneuvering or actuating the rest of the apparatus.
Although we prefer to carry our apparatus for supporting and moving
the combined scoop and rakes or hoes upon overhead rails, as shewn
in the Drawings, we do not limit ourselves to this arrangement, as we
sometimes so modify the apparatus as to adapt it for running along rails
laid upon the retort house floor.
When using steam power for driving or actuating the aforesaid
apparatus we prefer to mount the engine upon the same carriage or
cradle F that supports the scoop or scoops, and to supply the steam from
a stationary boiler through a flexible steam pipe.
Figures 12 and 13 represent respectively a longitudinal and transverse
section of a modified arrangement of scoop, which is here made in
the form of an oblong flat bottomed tray Q. This tray in lieu of being
turned over or reversed in order to deposit its contents on to the floor
of the retort is provided with a number of hinged doors or flaps t, t,
in the bottom (shewn in dotted lines), which are opened when released
by the weight of the coal thereon, and are closed again by short
chains attached to the several flaps and wound round a longitudinal
shaft, supported in curved brackets w over the centre of the tray, a
hand wheel or suitable gearing in combination with a ratchet wheel
and detent facilitating the rotation of the shaft, and maintaining the
flaps closed when not required to be opened. On releasing the shaft
the several flaps will fall open, and the coal will descend on to the bottom
of the retort. The moveable blades or hoes d, d, are mounted on rocking
shafts e, e, as in the first arrangement, but they work through openings
left between the flaps forming the bottom of the tray in lieu of

page_text: working from the top of the scoop, as in the previous arrangement.
The outer end of the tray is made cylindrical, and is carried by a pair
of radial lever arms R, as before described with reference to the scoop,
the tray turning slightly in its bearings when the arms rise or fall,
in order to ensure the perfectly horizontal position of the bottom of
the tray at all elevations or angles of the radial supporting arms R.
We do not confine ourselves to the use of our peculiar blades or hoes
in conjunction with or attached to a scoop or tray, as two or more
such blades or hoes fitted on to rocking shafts, and made to cut through
the coke transversely from side to side of the retort at two or more
points simultaneously by the partial rotation of the said shafts, may
be used in combination with a central carrier bar alone, the bearings
for the hoe shafts being secured to one or both sides of such bar. When
being inserted into the retort the blades or hoes will lie against the
sides of the bar, but when brought into action they will project below
such bar.
This frame
retort mouth,
In order that the retorts may be charged and discharged with facility
by means of the aforesaid apparatus it is found expedient to provide
them with hinged doors or covers in substitution for the ordinary loose
covers, each retort mouth having its own door. For this purpose we
propose to apply to existing retorts, whether of the circular or D section,
a cast-iron frame A, shewn by the sectional elevation and front view
of one end of a retort at Figures 14 and 15 respectively.
may be secured by bolts or otherwise to the ordinary
and carries a hinge B, to which the door C is hung. On the inner
face of the door there is provided a projecting rim a, which fits into a
corresponding groove in the frame A, such groove being filled with any
good lute before the door is closed. By this means a perfectly gas-tight
joint is readily obtained. The door is tightened up by a central screw
in the swivel cross bar b, which fits into lugs c, c, at the top and bottom
of the frame.
Figures 16 and 17 represent respectively a sectional elevation and
front view of a mode of combining two, three, or more retorts with
one chamber and ascension pipe, whilst at the same time facility is
afforded for gaining access to each retort separately, without interfering
with the working of the rest of the retorts in the said chamber.
A is the chamber in connection with which three retorts B, B, B,
are shown, and one ascension pipe C. Three passages D, D, D, are

page_text: made through the chamber corresponding to the several retorts and
forming continuations thereof. Each of these passages or extensions
of the retorts is closed by a small hinged door E of its own, by which
means access to any one of the retorts may be obtained, without
interfering with the others. The gas passes from the retorts into the
chamber A, through the orifices F, F, in the passages D, the said orifices
being each provided with a screw valve or cover a; by the closing of
which that particular retort is shut off from the chamber, in order to
prevent any escape of gas from the chamber, which continues to be
supplied through the orifices F in connection with the other retorts.
Thus any one of the retorts may be opened for the withdrawal of its
charge, or for sealing or other purpose, without stopping the working of
the rest, and without any escape or loss of gas.
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 Inven-
tion secured to us by the herein-before in part recited Letters Patent
is,
First. The construction and use of a scoop or tray having moveable
blades or hoes combined therewith, and operating substantially in the
manner and for the purpose herein-before described.
Second. The use of a tray having hinged doors or flaps in the bottom
tliereof, as and for the purpose herein-before described.
Third. The combination with a tray having hinged doors or flaps in
the bottom thereof of moveable blades or hoes, as and for the purpose
herein-before described.
Fourth. The use of two combined scoops or trays and sets of blades
or hoes in one retort, as and for the purpose herein-before described.
Fifth. The use of two or more moveable blades or hoes mounted on
a rocking shaft or shafts, and operating substantially as and for the
purpose herein-before described.
Sixth. Supporting the framing and mechanism which carries and
actuates one or more combined scoops and moveable blades or hoes on
overhead rails, substantially as herein-before described.

page_text: Seventh. The use of adjustable radial arms for carrying a scoop or
tray or combined scoop, or tray and hoes, substantially as and for the
purpose herein-before described.
Eighth. Mounting the motive power employed for running scoops or
trays or combined scoops or trays and hoes in and out of the retorts
upon the same cradle which carries the said scoops or trays.
Ninth. The application to ordinary retorts of grooved door frames
and hinged doors provided with projecting ledges, substantially as and
for the purpose herein-before described.
Tenth. Continuing the ends of the retorts through a
through a chamber
provided with a separate door for each retort, when such retorts are
made to communicate with the said chamber through a lateral valvular
opening, substantially as and for the purpose herein-before described.
In witness whereof, we, the said James Dunbar and Richard
Nicholson, have to this Specification set our hands and seals, the
Twenty-third day of October, One thousand eight hundred and
sixty-eight.
JAMES DUNBAR.
(L.S.)
RICH. NICHOLSON. (L.S.)