Im- PROVEMENTS IN COKING COAL AND OTHER CARBONACEOUS MATTERS, AND IN THE APPARATUS EMPLOYED THEREFOR.
Year: 1874

page_text: LETTERS PATENT to Henry Aitken, of Falkirk, in the County of
Stirling, North Britain, Coal Master, for the Invention of "Im-
PROVEMENTS IN COKING COAL AND OTHER CARBONACEOUS MATTERS, AND IN THE
APPARATUS EMPLOYED THEREFOR. "
PROVISIONAL SPECIFICATION left by the said Henry Aitken at the
Office of the Commissioners of Patents, with his Petition, on the
5th January 1874.
I, HENRY AITKEN, of Falkirk, in the County of Stirling, North
Britain, Coal Master, do hereby declare the nature of the said Inven-
tion of "IMPROVEMENTS IN COKING COAL AND OTHER CARBONACEOUS MATTERS AND
IN THE APPARATUS EMPLOYED THEREFOR," to be as follows, that is to say :-
This Invention which relates to improvements in coking coal and
other carbonaceous matters, consists in forcing or blowing air, which
may be heated or cold, into the upper part of coking ovens or kilns, that
is to say, into the space between the upper surface of the coal or
carbonaceous matter and the roof of the ovens or kilns,

page_text: This improvement is applicable both to ordinary coke ovens or kilns
as well as to the improved ovens or kilns herein-after set forth; it is
preferred that the air so forced in be heated. The object in so forcing
or blowing in the air above the coal or carbonaceous matter is to
burn the whole or a portion of the escaping gases, thereby effecting the
coking operation.
In carrying out the Invention the material to be coked is placed in
the oven or kiln and ignited in the ordinary manner, and so soon as
sufficient gas comes off all the apertures except the gas or smoke exit are
closed, and the air blast is applied and continuously blown in so long as 1
gas continues to be given off by the materials, after which the materials
may be drawn or allowed to remain in the oven or kiln to cool.
The gases resulting from the operation may be employed for raising
steam or for forcing or blowing in the air, and they may be applied for
heating the air to be used in the kilns or ovens, or for heating and 1
raising steam for other purposes.
The improved coke oven or kiln is constructed with the bottom or.
roof or both moveable, that is to say, so that either the bottom or roof
or both may be raised or lowered.
The moveable bottom or roof or both may be constructed of iron lined
with fire-brick or other refractory material, and either or both of them
are capable of being raised or lowered and fixed at any required level by
blocks and tackle, hydraulic rams, racks and pinions, or the equivalent
of these.
For simplicity of description in the following part of the Provisional
Specification the improved coke oven or kiln is referred to as having the
bottom moveable downwards, but it is to be understood that when the
top is made moveable it is also furnished with adjuncts similar or
equivalent to those herein-after set forth with reference to the moveable
bottom.
Below the oven there is an air-tight chamber of sufficient dimensions
to allow the moveable bottom to descend thereinto. This chamber is
provided with a door at one side and at another side with one or more
ventilating holes or safety valves, so that should the gas explode in the
chamber it will do no harm.
In operating with the improved oven the bottom is first raised to its
highest position so as to close the coking or carbonising chamber which

page_text: is then charged in the ordinary manner with the materials to be coked
or carbonised. After the first charge is coked or carbonised, the gases
being driven out, and while the coke and the oven are still hot, the
bottom of the oven is lowered sufficiently to allow of another charge of
materials being placed above it, which in its turn is also coked or
carbonised, after which the bottom with the coke resting thereon is again
lowered to allow another charge of materials to be placed in the oven.
It is obvious that the bottom may in the manner herein-before set
forth be arranged for lowering to any extent necessary for carrying any
required number of charges above it. When the bottom has descended
to within one or two feet or thereabouts of the discharging floor (the
bottom being hung on centres or pivots or their equivalent) is tipped
and the several charges of coke are deposited ready for removal; or
the bottom with the coke upon it may be thrown out on to a carriage,
or wheels may be applied to the moveable bottom of the kiln or oven
80 that it may be run out with the charge and another bottom put into
the chamber and the coking continued as before.
The chamber may be provided with two doors and the space between
them filled with sand so as to exclude the air.
An essential feature of the improved coke oven or kiln is that the heat
of the successive charges of coke is utilised for effecting the succeeding
coking or carbonising operations, so that fuel, time, and material are
economised.
Under a modified arrangement of the oven or kiln it is made deep
enough to contain several charges, and when the final charge of material
is placed therein the air is blown or forced in near the top of the coal.
When the charge is coked another charge is placed upon it and the flow
of air is directed to near the top of the second charge and so in
succession for any number of charges.
In order to prevent waste of coke in coke ovens or kilns where the
coke is allowed to remain until cool carbonic oxide or other neutral gas
is forced or blown into the ovens or kilns which are thereby kept full
of gas, and so no air gets admittance.
In cases where the coke is removed from the oven or kiln whilst hot,
it may be placed in an air-tight chamber to cool.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Aitken in the Great Seal Patent Office on
the 4th July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
AITKEN, of Falkirk, in the County of Stirling, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of January, in the year
of our Lord One thousand eight hundred and seventy-four, in the
37th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Aitken, Her special license
that I, the said Henry Aitken, my executors, administrators, and
assigns, or such others as I, the said Henry Aitken, my 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
COKING COAL AND OTHER CARBONACEOUS MATTERS, AND IN THE APPARATUS EMPLOYED
THEREFOR," upon the condition (amongst others) that I, the said Henry
Aitken, by an instrument in writing under my hand and seal, 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 calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Henry Aitken, 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 accompanying Drawings,
and to the letters and figures marked thereon, that is to say :—
My said Invention, which relates to improvements in coking coal and
other carbonaceous matters, consists in drawing, blowing, or forcing air,
which may be heated or cold, into the upper part of coking ovens or
kilns, that is to say, into the space between the upper surface of the
coal or carbonaceous matter, placed in the oven or kiln to be coked,
and the roofs of the ovens or kilns.

page_text: My said Invention is applicable to ordinary coke ovens or kilns as well
as to the improved ovens or kilns constructed in accordance with this
Invention and herein-after particularly described. It is preferred that
the air so forced in be heated. The object in so drawing, forcing, or
blowing in the air above the coal or carbonaceous matter is to burn the
whole or a portion of the escaping gases, thereby effecting the coking
operation.
And in order that my said Invention may be properly understood I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, reference being had to the annexed Sheets of Drawings, and to
the letters and figures marked thereon, that is to say :—
On Sheet 1 of the Drawings hereunto appended Figure 1 is a vertical
section and Figure 2 a part plan and part horizontal section on the
line a, b, Figure 1, of a circular coking oven or kiln constructed to coke
coal or other carbonaceous matter in accordance with this Invention.
As shewn at Figure 1 the oven or kiln is constructed with a chamber
or space A in the roof thereof which communicates with the outer
atmosphere, or with a pipe or passage through which air is conducted by
the opening or aperture B and with the interior C of the oven or kiln
by the perforations or air passages x, Figure 1. The kiln or oven is
formed with ports or openings D communicating between the interior C
of the oven or kiln and the flue E, which extends around the kiln or
oven from each side of the charging and drawing doorway F to the
flue G, through which the products of combustion are conveyed away
from the oven or kiln by means of a stalk or chimney, or other means
of producing a draught. The flue G is provided with dampers I, I¹, for
regulating the draught, and a side damper I² is provided in order that
should leakage occur at the damper I¹ the draught of the chimney may
draw air through the opening at I³, and not through the oven or
kiln.
In operating with this arrangement of oven or kiln the coal or other
carbonaceous matter to be coked is introduced to the interior thereof
through the doorway or opening F and ignited in the ordinary manner,
and so soon as sufficient gas comes off or is evolved from the material
being coked a wall is built or other stopping put in across the opening
at F inside the flue E, and plastered up so as to connect the side walls,

page_text: and leave a space for the gases to pass round. The outside doorway or
opening at F is also closed, and the draught through the flues E and G
draws atmospheric air through the opening and chamber B and A to the
interior C of the oven or kiln, whereat it comes in contact and mixes
with the gases arising from the coal or other carbonaceous matter,
burning the whole or a portion of the same, producing a very high
temperature, and thereby coking the charge, after which the products of
combustion pass off through the ports or passages D and flues E and G.
The admission of air is continued and regulated as long as gas continues
to be evolved from the materials being coked, after which the said
materials may be watered out and withdrawn or allowed to remain in
the oven or kiln to cool, and in place of drawing in the air by the
action of a chimney it may be blown or forced in under pressure in the
oven constructed as shewn at Figures 1 and 2, Sheet 1.
Another arrangement of carrying out my improvement is illustrated
in part transverse section and part end elevation at Figure 3, Sheet 1 of
the Drawings; in part horizontal section on the line g, h, Figure 3, and
in part plan at Figure 4; also in longitudinal section on the line e, f,
Figure 4. At Figure 5 the air is drawn, blown, or forced through pipes A
placed in flues B, situate at each side of the oblong cooking ovens or a
kilns C, between which and the flues B communication is effected by the
ports or openings D. From the pipes A winding or meandering pipes E,
the contours of which are more particularly seen in dotted lines at
Figure 5, Sheet 1, conduct the air blast to chambers F formed in the
roof of each oven or kiln C, from whence it passes to the interior thereof 2
through the apertures or perforations x, mixing with and consuming
the gases evolved by the material being coked as herein-before described
in reference to Figures 1 and 2, Sheet 1. The material to be coked is
introduced to and withdrawn from the oven or kiln through the doorway
at G, which is closed, and the inside wall built up, as herein-before
described, after the material has been properly ignited, and these openings
are kept shut as long as gas continues to be evolved from the material.
Dampers I are placed in the flue H of the coking oven or kiln to regulate
the draught, and a side damper I¹ is provided for the purpose herein-
before set forth. The side flues B are closed at each end by doors (not
shewn on the Drawings), but which are movable, to afford access to the
interior of the flues, and access is also had to the interiors of the pipes E
by removing the covers J and upper portions a of the bends at the

page_text: junctions thereof, which portions are made separate from the remainder
of the bends. When the cover J and portion a have been so removed
the passage to the chamber F may be closed by the stopper P.
On Sheet 2 of the Drawings bereunto appended Figure 1 is a vertical
section, Figure 2 a side elevation, and Figure 3 a part plan and part
horizontal section on the line c, d, Figure 1, of a coking oven or kiln,
shewing applied thereto another system or mode under which heated air
is drawn, blown, or forced into the upper part of the oven or kiln in
accordance with this Invention. Under this arrangement the air consti-
tuting the blast is forced or conducted through a pipe A situate in the
lower part of the flue B, and from which branch pipes A¹ extend around
the oven or kiln in the flues D, as shewn. From the pipes A¹ the air is
conducted through the winding or meandering pipes F, the forms of
which are more particularly seen by the dotted lines at Figure I, from
whence it passes into the box or chamber J. After a charge of coal or
other carbonaceous matter has been introduced into the oven through
the doorway E, and when the said charge has been ignited in the
ordinary manner, and sufficient gas comes off, the doorway E being then
closed, the valve Kin the chamber J is raised, whereby the air is allowed
to pass from the chamber J into the chamber L, and thence through the
perforations or air apertures x to the interior of the oven or kiln, where it
meets and mixes with the gases evolved from the carbonaceous matter,
consuming them and producing the heat for effecting the carbonising of
the fuel, as herein-before described. The products of combustion pass
from the oven or kiln through the ports or openings M, and thence
through the flues D into the flue B, by which means the air passing
through the pipes A, A', and F is heated before being discharged into
the coking oven or kiln.
:
Under another arrangement of forcing or blowing heated air into the
upper part of coking ovens or kilus illustrated in vertical section at
Figure 4, and in part plan and part horizontal section on the line e, d,
Figure 4, at Figure 5 (Sheet 2) of the Drawings, the air after being
forced or blown through the pipe A situate in the main flue B, and
being heated therein or previously heated by the waste gases from
the oven or otherwise passes through the branch pipe C seen more
particularly in plan at Figure 5, into the pipe D from whence it is blown
into the upper part of the oven or kiln through the twyers or jets x.
The oven or kiln may be charged through the holes G in the top or

page_text: charged and drawn through the opening or doorway E, and the products
of combustion pass off from the oven or kiln by the port or opening C
to the main flue B.
Under the system last described any desired number of coking ovens
or kilns may be situated in a double line on each side of the main flue
as shewn at Figure 5, Sheet 2, and cocks or fly valves may be provided
by which to regulate or cut off the air blast from any one or more of such
ovens, or the blast may be cut off by forming the branch pipe C in two
sections from which when it is desired to stop the blast the junction
piece a is drawn back, and the ends of each section of the pipe closed
by a stopper or plug.
.
The waste products of combustion resulting from the coking of coal or
other carbonaceous matter in any of the ovens herein described and
shewn, may besides heating the air blast be employed in raising steam
for forcing or blowing the air into the upper parts of the ovens or kilns
or for heating and raising steam, or a portion of the gases may be
conveyed away from the ovens or kilns for other purposes. When there
is more tarry matter than is necessary for "grindering," the carbonaceous
matter being coked or carbonised a portion of the same may be drawn
off at the bottom of the ovens or kilns by means of pipes and thereafter
condensed, and thereby a portion of the tar and tar water is secured.
On Sheet 3 of the Drawings hereunto appended the improvements in
supplying the air blast to coking ovens or kilns are illustrated in
longitudinal section at Figure 1, and in transverse section on the
line a, b, Figure 1, at Figure 2, as applied to a coking oven or kiln
provided with a charging and drawing apparatus operated horizontally
in the well-known manner by steam power from a boiler at A. Under
this arrangement in which any number of kilns or ovens may be placed in
a row the air blast is forced or blown into the pipe B, from which branch
pipes C at each side of the oven or kiln convey the air blast to twyer
holes x, at which it is discharged on the gases arising from the
carbonaceous matters being coked or carbonised, whereby the said gases
or a portion thereof are consumed and the coking operation is thereby
effected. If desired the gases may after leaving the oven or kiln as
herein-before described be taken along the sides over or under the ovens
or kilns, and air may also be added at numerous points so as to consume
more thoroughly the gases, and exhaust their heating powers in coking
the carbonaceous matters.

page_text: My said Invention also relates further to a special arrangement of
coking ovens or kilns, by or in which coking operations are rendered
continuous, that is to say, several charges of coal may be coked suc-
cessively and all of which are ultimately drawn from the improved ovens
or kilns at one operation. This part of my Invention consists in
constructing the bottom or roof of the kiln or oven movable, that is to
say, capable of being raised and lowered and fixed at any required level
by means of hydraulic rams, racks, and pinions, or by blocks and tackle,
or the mechanical equivalent of these.
.
On Sheet 4, of the Drawings hereunto appended Figure 1 is a vertical
section; Figure 2, an elevation of the end marked A, Figure 1; and
Figure 3, a transverse section on the line a, b, Figure 1, of a coking
oven or kiln constructed in accordance with this part of my said Inven-
tion. The oven or kiln is formed as an air-tight chamber A, at one side
of which a doorway B is situate at the lower end of the chamber, and at
or near to the upper end of the chamber vents or passages C are formed
in one end thereof, so that should the gas arising from the carbonaceous
matter being coked explode in the chamber it will do no harm as by the
force of the explosion, the plugs D by which the passages or vents are
closed are blown outwards from their seats. The vents or passages C
also serve as holes through which is spread the carbonaceous matter over
the bottom of the oven. The plugs D are suspended from chains passed
over pulleys E at the opposite extremities of which counterweights Ę are
attached. The opening B is closed by doors B¹, B³, when the oven or
kiln is in operation, and it is preferred to make the door B¹ of iron lined
with brick or fire-clay.
In case the gases explode in the lower part of the oven or kiln a
safety valve w is placed in the door B³, which allows the gases to escape
similarly to the valves D at the other side of the oven. The bottom F
of the oven or kiln, which is capable of being raised and lowered, and
fixed at any desired position by the hydraulic ram G, is preferably made
of iron with a sole composed of slabs of fire-clay, or other refractory
material; and it is provided with wheels H, by which the bottom F
when at its lowest position may be run on rails out of the chamber of
the oven or kiln. When in a raised position the movable bottom F is
supported on a framing or platform I fixed on the head of the ram G, as
shewn. A light rope or chain J is attached to the framing or platform I,
and passed round pulleys K to the outside of the oven or kiln,

page_text: whereat it is attached to a small weight L by which the position of the
movable bottom at the interior of the oven or kiln is indicated, the
weight L rising and falling with the bottom F. Charging openings M.
are formed in the arch of the oven or kiln on each side of the flue N,
and these are provided with plugs O for closing them. The plugs or
stoppers are of fire-clay, or other refractory material. The air for
burning the gases issuing from the substances being coked is forced or
blown through the pipe P, Figure 2, from whence it passes into
the pipes Q at each side of the oven or kiln, and enters the upper part
thereof between the charges of material being coked or carbonised, and
the arch R through the twyers or jets x, and impinging upon the gases
evolved from the said materials, consumes or partially consumes the
same, the products of combustion thereafter passing off through the
flue N.
In operating with the oven or kiln now under reference the bottom F
is first raised to its highest position (the position shewn at Figure 1,
Sheet 4), by forcing water into the cylinder S for raising the ram G and
bottom F. The oven or kiln is then charged through the openings M
with the material to be coked or carbonised, which is ignited through
the openings M, or through the vents or passages O; and when sufficient
gas begins to be evolved therefrom the openings M, and vents or
passages C, are closed by their respective stoppers or plugs, and the air
blast is blown in through the twyers x. After the first charge has
been coked or carbonised by the heat of the burning gases, and whilst
the coke and the oven or kiln are still hot the ram G is allowed to
descend, thereby carrying down the movable bottom F and coke thereon
a distance sufficient to receive another charge of carbonaceous matters
above the coke. This second charge is in its turn also coked or car-
bonised, and thereon is again moved downwards, after which the bottom
with the two charges of coke is lowered to receive a third charge, this
succession of lowering and coking operations being continued until the
movable bottom reaches the lower end of the chamber, when, with the
coke upon it, it is run out on the rails 6, and removed, after which the
bottom is replaced in its position above the ram G (or another movable
bottom may be substituted therefor) the ram with the bottom is raised
again in the chamber A, and the oven is then ready for receiving another
succession of charges. The oven is preferably formed with a slight
taper from the bottom to the top, so as to allow the charge to descend

page_text: without much friction, and the door side of the oven is preferably made
wider, so as to permit of the coke being withdrawn with facility. A
scale is or may be fixed in the brickwork of the oven or kiln opposite*
the hanging weight L, by which means the descent of the movable
bottom at each succeeding charge of carbonaceous matters is or may be
indicated.
An especial feature of the coke oven or kiln herein-before described
and shewn on Sheet 4 of the Drawings is that the heat of the successive
charges of coke is utilized for effecting a portion of the succeeding
coking operations, so that fuel, time, and material are economised. By
the high heat obtained at once the oven or kiln last described is capable
of coking or carbonising many substances that will not coke in ovens or
kilns as hitherto constructed.
In lieu of raising, lowering, and fixing at any desired level the
movable bottom of the coking oven or kiln constructed in accordance
with my said Invention by a hydraulic ram as herein-before described
and shewn, racks and pinions may be employed for that purpose, as
shewn in vertical section at Figure 1, Sheet 5 of the Drawings, in
transverse section on the line c, d, Figure 1, at Figure 2, in part
elevation of the end marked A, Figure 1, at Figure 3, and' in horizontal
section on the line a, b, Figure 1, at Figure 4. Under this arrangement
racks A are attached to the movable bottom B at or near the four
corners thereof, which racks descend into wells C when the movable
bottom is being lowered, a roller D being placed at the back of each
rack, as shewn at Figures 2 and 4, to afford support thereto. Pinions
E, fixed on shafts F, gear one into each rack A, and the shafts F are
also geared together at one end by spur wheels G, on the axis of one of
which a worm wheel H is also fixed. Into the worm wheel H a tangent
screw or worm I, carried on a vertical shaft J, is geared, and the shaft J
is rotated by the bevil gearing K situate at the upper end thereof. A
second worm wheel L is also placed loosely on the shaft J and geared
thereto when desired by the clutch M, which, when not in the position'
shewn on the Drawings, is retained out of gear with the worm wheel L
by pinching screws a. The worm wheel L is geared with a tangent
screw on the axis b.
When it is desired to lower the movable bottom B, the weight being
then comparatively heavy by reason of the superposed carbonaceous*
matter, the tangent screw at 6 and worm wheel L are employed to

page_text: actuate the shaft J, but when it is desired to raise the movable bottom
B the worm wheel L is thrown out of gear by removing the clutch M,
and the bevil gearing K is employed for that purpose. In this arrange-
ment of coking oven or kiln the operation of coking or carbonising the
charge, and of removing the same from the oven or kiln is similar to
that herein-before described in reference to Sheet 4 of the Drawings.
In lieu of mounting the movable bottom on wheels for the purpose of
removing the coke from the oven or kiln the bottom may be hinged on
a pivot or joint and tipped up by any suitable means and the coke
deposited on a truck or carriage, or at the doorway of the oven or kiln.
It is to be here understood that in lieu of making the bottom of the
oven or kiln movable, as herein-before described, the roof or upper part
of the oven or kiln may be made capable of being raised and lowered
and fixed at any required level to coke or carbonise successive charges
of carbonaceous matters superposed one on the other, which raising and
lowering may be effected by hydraulic rams, racks, and pinions, or by'
blocks and tackle, which latter means may also be employed for raising
and lowering the movable bottom instead of the bydraulic and rack and
pinion arrangements, Sheets 4 and 5.
Under another arrangement both the bottom and upper part of the
coking oven or kiln may be made movable by the means herein-before
described. The air may be forced or blown into the ovens or kilns
herein-before described by means of a blowing engine or fan, or other
contrivance, or it may be forced in by heating the air at a lower level
than the ovens. When the air is drawn into the ovens or kilns this may
be effected by an exhaust fan by the draught of the chimney or stalk, or
by steam or water jets, the exit of the gases in any case being regulated
by means of dampers or stoppers placed in the flues or outlets of the
ovens or kilns.
In lieu of heating the air by conducting it through pipes placed in the
gas exit flues it may be heated in a separate air heating apparatus
communicating with the ovens or kilns by pipes, around and amongst
which the gases from the ovens or kilns are made to circulate, or the
air may be heated by passing it and the gases through flues alternately,
and these flues may be made large and partly filled with brick, or other
refractory material. More air may be added to the gases as they pass
through the flues or heaters in order to exhaust their heating powers.

page_text: It is to be specially observed that it is of great advantage to introduce
the air to the ovens or kilns in the modes herein-before described as
highly heated as possible and at numerous small apertures, and it is
also of advantage to direct the air upwards as it enters the oven or
kiln.
It is obvious from the construction of the improved ovens or kilns
embraced by this Invention, and from supplying the air to coking ovens
or kilns in the manner illustrated on the several Sheets of Drawings
hereunto appended, that the amount of air passing into the ovens or
kilns may be so regulated as to consume only the gases arising from the
carbonaceous matters being coked or carbonised, or such portion thereof
as may be required to effect the coking or carbonising operation without
consuming the coke or carbonaceous matters themselves.
Having now described and particularly ascertained the nature of my
said Invention and the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, I would observe
in conclusion that what I consider to be novel and original, and there-
fore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,―
First. Drawing, forcing, or blowing atmospheric air, cold or heated,
through numerous small apertures into the upper parts of coking ovens
or kilns so as to burn within the ovens or kilns the gases arising from
the materials being coked, whereby the coking or carbonising operations
are effected, and undue waste of solid carbonaceous matter is prevented
as herein-before described.
Second. The improved arrangements and constructions of coking
ovens or kilns with movable bottoms or tops, or with both the top and
bottom movable, whereby several successive charges of carbonaceous
materials are coked or carbonised, as herein-before described and in part
illustrated on Sheets 4 and 5 of the Drawings.
In witness whereof, I, the said Henry Aitken, have hereunto set
my hand and seal, this Thirtieth day of June One thousand
eight hundred and seventy-four.