Improvements in Apparatus Employed in the Continuous Production or Distillation of Gas and other Products from Coal and other Materials and Minerals.
Year: 1887

page_text: Date of Application, 2nd Dec., 1887
Complete Specification Left, 3rd Sept., 1888
Complete Specification Accepted, 19th Oct., 1888
Improvements in Apparatus Employed in the Continuous Production
or Distillation of Gas and other Products from Coal and other
Materials and Minerals.
I JOHN DEMPSTER of the firm of R. and J. Dempster of the Gas Plant Works,
Newton Heath, near Manchester in the County of Lancaster, Engineers do hereby
declare the nature of this Invention to be as follows:-
My said Invention relates more particularly to the retorts and attachments used in
the manufacture of illuminating gas from coal as is well understood. The charging
and drawing of these retorts if done by hand is laborious and uncertain, while most
of the machines at present in use for these purposes are expensive in prime cost,
difficult to keep in order and occupy considerable space. I have therefore devised an
apparatus which is easily worked, occupies little room and is considerably cheaper
than existing machines, while the retorts are or may be charged and the coke removed
either continuously or intermittently as desired. Above the charging end of the
retort I place a hopper which is filled with coal through an aperture, which is closed
by a water-sealed or luted or faced door. The coal placed in this hopper, falls into
the charging throat of the retort and is from time to time pushed forward into the
retort by a piston or ram which slides in a chamber in front of the retort. This ram
may be worked backward and forward by a rack and pinion or by levers and links or
by other arrangements suitable for reciprocating the ram. Although the said ram
is capable of being worked by a manually operated shaft or handle I prefer to work
it automatically from a revolving shaft extending in front of the range of retorts.
The said revolving shaft works the rams of the series of retorts by means of cams or
cranks or eliptical wheels or other suitable mechanism for reciprocating the rams
intermittently and at the proper intervals of time, the rams being pushed in and
immediately pulled out so as not to subject them unduly to the heat of the interior of
the retorts. In front of each ram we fix a projecting shelf which acts as a depresser
to keep the coal down as it is pushed into the retort and so prevent it from becoming

page_text: banked up in the centre of the retort which might otherwise occur. Instead of the
pushing ram herein before referred to I might employ a charging apparatus consisting
of a revolving screw or spirally formed blade or plate or series of blades set at
intervals in a spiral form on a revolving shaft so as to feed the charge continuously
forward into the retort. The coke is delivered at the other end of the retort by the
pushing action of the charging apparatus and to permit a ready delivery I form a
branch or trunk on the delivery end of the retort. This trunk extends downward
and is closed at the bottom by a hinged flap or plate which may lie in a horizontal
or inclined plane. The said hinged plate is held against the bottom end by counter-
balance weights or other convenient means and both the end of the trunk and the
meeting face of the hinged plate are preferably turned or machined so as to make a
gas tight joint. The hinged plate may be allowed a little lateral play so that the
joining edges or faces may be cleared of intervening grit or obstacles by slightly
moving or shaking the plate laterally on its hinge. As the coal is fed into the retort
by the reciprocating rain or by the screw or helical blade or blades the coke is corre-
spondingly fed forward so as to fall into the delivery trunk. When the trunk is full
or otherwise at such intervals as may be considered advisable the hinged plate is
opened and the coke contained in the trunk is allowed to fall out upon the ground or
into a receptacle or truck waiting to receive it. To break up the coke and cause it
to fall more readily into the delivery trunk we may arrange a poker or other means
to be operated from the outside when required, but if the trunk is made sufficiently
large, these breaking up appliances need not necessarily be employed. The counter
balance weight of the hinged plate at the foot of the trunk might be carried in ways
or between fences and be arranged to allow the plate to swing open automatically
when the trunk is full of coke, the weight running toward the pivot as the plate
swings open and closing the plate again when the coke has fallen out. Instead of a
hinged plate I might employ a sliding door to close the foot of the trunk. When
the retorts are set one above another their ends would be connected by a common
delivery trunk. If desired a positive delivery of the spent charge of the retort
might be effected by placing a revolving spiral rod or blade or other disturbing or
drawing means in the delivery trunk, which would also serve to break up the caked
or clinkered portions of the spent charge and cause it to fall more readily into the
delivery trunk. Although I have referred in the foregoing description to my improve-
ments as being chiefly applicable to the manufacture of illuminating coal gas it will
be understood that the improved arrangements or parts of them are also applicable to
the distillation in retorts of vegetable or other substances and of minerals as for
example in the distillation of oil from shale.
Dated this 1st day of December 1887.
DUTTON & FULTON,
1,.St. James Square, Manchester,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus Employed in the Continuous Production
or Distillation of Gas and other Products from Coal and other
Materials and Minerals.
I JOHN DEMPSTER of the firm of R. and J. Dempster of the Gas Plant Works,
Newton Heath, near Manchester, in the County of Lancaster, Engineers, do
hereby declare the nature of this Invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement and accompanying drawings:—
My said Invention relates more particularly to the retorts and attachments used
in the manufacture of illuminating gas from coal as is well understood. The charging
and drawing of these retorts if done by hand is laborious and uncertain, while most
of the machines at present in use for these purposes are expensive in prime cost,
difficult to keep in order and occupy considerable space. My improved apparatus is
easily worked, occupies little room and is considerably cheaper than existing machines,
while the retorts are or may be charged and the coke removed either continuously or
intermittently as desired. Above the charging end of the retort I place a hopper
which is filled with coal through an aperture, which is closed by a suitable door.
The coal placed in this hopper, falls into the charging throat of the retort and is from
time to time pushed forward into the retort by a piston or ram which slides in a
chamber in front of the retort. This ram may be worked backward and forward by
a rack and pinion or by levers and links or by other arrangements suitable for
reciprocating the rain. I prefer to work the said ram automatically from a revolving
or rocking shaft extending in front of the range of retorts. The said shaft works the
rams of the series of retorts by means of cams or cranks or cliptical wheels or other
suitable mechanism for reciprocating the rams intermittently and at the proper
intervals of time, the rams being pushed in and immediately pulled out so as not to
Instead of the pushing
subject them unduly to the heat of the interior of the retorts.
ram herein before referred to I might employ a charging apparatus consisting of a
revolving screw or spirally formed blade or plate or series of blades set at intervals in
a spiral form on a revolving shaft so as to feed the charge continuously forward into
the retort. The coke is delivered at the other end of the retort by the pushing action
of the charging apparatus and to permit a ready delivery 1 form a branch or trunk
on the delivery end of the retort. This trunk extends downward and is closed at the
bottom by a binged flap or plate which may lie in a horizontal or inclined plane. As
the coal is fed into the retort by the aforesaid means the coke is correspondingly fed
forward so as to fall into the delivery trunk. When the trunk is full or otherwise at
such intervals as may be considered advisable the hinged plate is opened and the
coke contained in the trunk is allowed to fall out upon the ground or into a receptacle
or truck waiting to receive it. The counter balance weight of the hinged plate at
the foot of the trunk might be carried in ways or between fences and be arranged to
allow the plate to swing open automatically when the trunk is full of coke, the weight

page_text: running toward the pivot as the plate swings open and closing the plate again when
the coke has fallen out. Instead of a hinged plate I might employ it sliding door to
close the foot of the trunk. When the retorts are set one above another their ends
would be connected by a common delivery trunk.
And in order that my said invention may be properly understood I will now proceed
more particularly to describe and ascertain the nature of the said improvements
and the system mode or manner in or under which the same is or may be used
or carried practically into effect, reference being had to the annexed 12 sheets of
drawings and to the letters and figures marked thereon to be as follows that is
to say :-
Fig. 1. sheet 1 of the drawings is a front elevation of a set of gas making
retorts to which one arrangement of my improved charging apparatus is shown
applied.
Fig. 2 is a vertical section of the retorts at right angles to Fig. 1.
Fig. 3 is an end elevation at the coke delivery or discharging end.
Fig. 4 is a plan.
The remaining Figures 5.6, 7, 8, and 9, on sheet 1 illustrate details of the parts
to which reference will be made in the course of description.
In the said drawings the apparatus (that is to say one of the several modifications
or arrangements of my apparatus) is shown applied to a set of six retorts
A. B. C. D. E. F. arranged in vertical sets of three and side by side. It will
however be understood that the apparatus is capable of application to single retorts
or to sets of retorts of any suitable number or disposition. In front of each retort
I place a mouth piece G which contains the reciprocating ram H by which the coal is
thrust into the retort. This ram H. is shown to an enlarged scale in sheet 2 of the
drawings. In sheet 2 Fig. 10 is a longitudinal section of the ram H and mouth-
piece G. As will be hereinafter shown I do not limit myself to the particular means
for working the ram to and fro. In sheets 1 and 2 the ram H is formed with a
toothed rack I with which engages a toothed pinion J carried on a shaft K which is
supported in bearings in the mouth piece G. If the shaft K and pinion J are rotated
in the direction of the arrow (Fig. 10) the ram will be advanced, and if the motion
of the shaft and pinion is reversed the ram will be withdrawn. Before referring
further to the action of the ram I will now describe the means for feeding the coal
to the ram. Referring to sheet 1 it will be seen that above the set of retorts is
situated a hopper L closed at the top by a door M which can be slid to and fro by a
hand wheel, shaft and pinion N the pinion gearing with a rack on the door M.
When the door M is slid away from the opening, coal can be introduced to the hopper
and when the door is slid again into its closing position the opening is covered and
the escape of gases or of vapours is prevented. Instead of the sliding door M as
described I might use the revolving semicircular door O shown at Figs. 13, 14 and 15
sheet 3 of the drawings or the modified form with feed hopper P shown at
Figs. 16, 17 and 18 sheet 4 of the drawings. In the latter Figs. the hopper P has
an inclined bottom as clearly seen in Fig. 16 to direct the coal put into the
hopper toward the opening. Referring again to sheet 1 of the. drawings the coal
in the hopper L is led by branches R to the front of the retorts A. B. C. D. E. F.
and in front of the rams H. When the ram H is advanced the plate H' (see
Fig. 10 sheet 2) pushes the coal in front of it into the retort and when the ram is
withdrawn a fresh supply of coal falls down from the hopper L and lodges in front
of the ram ready to be pushed in by the next advance of the ram. To prevent the
loose coal from banking up in the mouth of the retort I. form the ram with a
projecting plate H2 which projects in front of the ram and prevents the coal from
rising above that level. When the fresh charge of coal falls from above in front
of the ram it falls through a hole. H³ in the plate H2 this hole being necessary to
allow the coal to pass the plate. When the charge of coal is beyond the reach of the
plate H2, it has been sufficiently long subjected to heat, to cohere and form a caked
mass which will not break up before the pressure of the ram. The coal occupying
the length of the retort is also sufficiently caked together by the heat to form a mass

page_text: which will not break or crumble up and which is pushed gradually through the retort
by the successive movements of the ram. Some classes of coal cohere more firmly
than others and the length of the retorts might be regulated in accordance with the
behaviour of the coal employed. The retorts may either be arranged in a horizontal
plane as shown in sheet 1 or they may be set at an angle sloping downward from the
front toward the back so as to assist the passage of the charge and render it less
liable to break up under the pressure of the rams. The mechanisin for automatically
advancing and retracting the rams is as follows, reference being had to sheets 1 and 5
of the drawings. Above the retorts and in front of the setting is a revolving shaft S
carried in bearings T and driven by a pulley and strap V from a small motor U or from
any other suitable source or transmitter of power. For each of the operating apparatus
there is on the shaft a worm W which gears with a worm wheel X, running loosely
on a stud Y. In the worm wheel X I form a cam groove Z. A jawed and
weighted bracket a hangs from the stud Y and has an arm b to which is pivotted the
link c.
At the upper end of the link c is a bowl which runs in the cam groove Z.
Midway between the arm and the bowl the link c is connected to a clutch half d
which slides on the shaft S and revolves therewith by means of a slip feather and
groove the other half of the clutch being loose on the shaft S and carrying an
excentric e. When the loop Z in the cam groove comes round and pushes the
bowl and link e to one side, the sliding and revolving half d of the clutch is pushed
into gear with the half d¹ whereby the half d together with the excentric e is caused
to make one revolution, the loop Z in the cam groove being calculated to give
exactly this length of contact between the halves of the clutch. The excentric
straps carry a fail which is formed as a rack and which gears with pinions g
which are fixed on the shafts K. The pinions are of such proportions that the
rise and fall of the rack will cause the shafts K to revolve sufficiently to give the
proper charging advance to the rams and also effect their withdrawal. To hold the
tail rack in gear with the pinions g I employ a bridle and bowl. The space of
time during which the bowl travels in the concentric portion of the excentric groove Z
represents the dwell which takes place before the ram is again advanced and withdrawn.
The hereinbefore described apparatus is shown to an enlarged scale in sheet 5 of the
drawings and as applied to a single retort instead of to a set. Fig. 19 is an end
elevation. Fig. 20 is a front elevation and Fig. 21 is a plan view. On the latter three
figs. I have placed letters of reference similar to those used in describing the apparatus
in sheet I and it will not therefore be necessary for me to recapitulate the description
of its working which is precisely in accordance with what has been already said.
The coal which has been fed into and traversed through the retorts in this manner
falls in the form of coke from the delivery ends into the coke delivery trunk i
which is simply a large upright box into which all of the retorts open and which
is provided with man or spy hole doors opposite to the several retorts. The gas
evolved in the retorts may be withdrawn in the ordinary manner or through an
outlet at the top of the trunk i. At the foot of the trunk is a hinged door through
which the spent charge or coke is discharged. The door is shown to a larger scale at
Figs. 5, 6 and 7 sheet 1. It consists of a plate which is applied preferably at an
angle as shown in Fig. 6 to the mouthpiece casting m. The casting m and the
plate are both machined or faced so as to make a good joint when the door is closed.
The door is held against the faced mouthpiece m by means of a counter-balance
weighted lever n which may be held when the door is closed by a hasp o. When the
trunk i contains sufficient coke the hasp is knocked aside and the door is allowed
to fall open and permit of the coke being discharged upon the ground or into a truck
or other suitable receptacle. Instead of having the counterbalance weight p fast
upon the tail of the lever n as in Figs. 6 and 7 it might be suspended to roll upon the
lever as shown in Figs. 8 and 9. Such an arrangement would be useful if the door
were arranged to open self-actingly and under a given weight of coke. By
arranging the lever at the proper angle the weight would roll up toward the door
when the door was opened by the weight of the coke and by thus lessening the effect of
the counterbalance weight the door would not immediately close again till the whole

page_text: of the coke was discharged whereupon the weight would roll toward the outer end
of the lever and close the door. One of the machined meeting surfaces of the door
and the mouthpiece should be made very narrow and the hinge should be made with
a little play so that when the door is closed it can be moved horizontally so as to rub
the meeting surfaces together and remove grit or particles of coke which might
prevent the joint from being perfectly gas tight. Instead of a hinged door as
described I might use a sliding door as shown in sheet 6, figs. 22, 23, and 24.
In this instance the mouth piece is fitted or formed with slides which carry the
door g. On the door is formed a rack q' and a pinion s on the shaft t gears with the
said rack so that when the shaft is turned by means of the handwheel u the door
is slid on one side so as to open the mouthpiece for the discharge of the coke.
I have now described and illustrated the whole process of continuously feeding,
charging and discharging the retorts in accordance with my invention which consists
mainly in the adoption and automatic operation by mechanical means of the feeding
or charging ram H. and the accessories for rendering its operation more successful,
satisfactory and complete.
It will however be apparent that mechanism other than that which I have described
and illustrated could be used with equal success and I will therefore now proceed to
describe one or two other arrangements and modifications of ram actuating mechanism
although I do not intend that such descriptions of alternative mechanism should be
considered at all exhaustive.
Referring to sheet 7, figs. 25, 26, and 27 are end and front elevations and plan
respectively of an apparatus in which I use a crank or crank disc v instead of an
excentric to raise and lower the rack f. The crank disc is secured to a shaft w
which is rotated at the requisite times by the following mechanism. Beneath the
shaft w I pivot a weighted tumbling lever a which takes hold of a sliding clutch half y
sliding on the shaft w with a slip feather and groove and formed to engage with
another clutch balf y' which is formed on the boss of a spur wheel z which runs loose
on the shaft w and is constantly driven by the pinion 1 on the constantly revolving
shaft 2. A worn on the shaft 2 imparts continuous motion to the worm wheel 3 and
at each revolution of the worm wheel a finger 4 cast thereon or attached thereto,
strikes the tumbling lever a over into the position shown most clearly at Fig. 26 in
which position the halves of the clutch are brought together and the shaft w and crank
disc are caused to make one revolution therefore raising and lowering the rack f
and consequently advancing and retracting the charging ram as hereinhefore described.
To prevent the shaft w and disc e from making more than one revolution I form an
incline 5 on the side of the spur wheel which incline moves the weighted tumbling
lever away from the spur wheel and so as to disconnect the halves of the clutch and
so stop the revolution of the shaft w. The positions of the finger on the worm wheel
and of the incline on the spur wheel are so arranged and set relatively to each other
that the tumbling lever is pushed over to connect the halves of the clutch just at the
time when the incline on the spur wheel has passed out of the range of the lever. The
time occupied by the worm in moving the finger round again into striking position
gives the requisite dwell between the several actuations of the ram.
The apparatus
shown on sheet 8 of the drawings is nearly similar to that shown on sheet 5 with the
exception that instead of the excentric I have shown a cam 6. The jointed link ƒ“¹ of
the rack carries the bowls 7 and 8 which bear upon each side of this cam. As the
cam is rotated at the proper intervals and to the proper extent as and by the means
already described with reference to sheet 5, the rack is raised and lowered and the
charging ram advanced and retracted. Instead of the bowls running on the periphery
of the cam 6 as described and shown they might occupy a cam groove of the proper
contour. In Figs. 31, 32, and 33 sheet 9 of the drawings I illustrate the employment
of what is technically known as a "mangle motion" to effect the rise and fall of the
rack. The head of the jointed link 1 of the rack is formed with internal teeth as
clearly shown at Fig. 31. A toothed pinion is formed on the clutch half and the
said pinion when gearing with one side of the internally toothed head 2 is clear of the
other side so that it moves the head up or down according to which of the sides it is in

page_text: gear with. When the pinion reaches the top or bottom of the head it follows the teeth
round to the other side and reverses the direction of traverse of the head. To permit of the
head swinging a little to one side or the other as the pinion reaches the top or bottom
of the toothed portion the upper part of the head slides in an inverted crutch 9 which
slides in a bracket 10 fixed to the front of the retort setting. The driving pinion is
operated in the same manner as the excentric shown in sheet 5. In sheet 10 Figs. 34,
35 and 36 the continuously revolving shaft 11 by a train of gearing drives the oval
wheels 12 which gear with each other and rotate the crank disc 13 which com-
municates motion to the rack and pinion whereby the charging ram is reciprocated.
The oval wheel arrangement although working continuously together gives such slow
motion to the ram on its return from the charging stroke that it is equivalent to the
dwell which I have referred to in the other modifications. On the other hand the
advance and withdrawal of the ram is from the same cause executed with such
comparative rapidity that the ram does not suffer from prolonged exposure to the
heat of the retort but is withdrawn as soon as its charge has been pushed forward.
It will be evident that the charging ram might be operated from the front of the
retort by a crank or excentric on a shaft which might be caused to revolve at intervals
by means the same as or similar to those already described as suitable for producing
such a movement; or instead of moving the rains at stated intervals of time as
described they might be reciprocated or advanced and withdrawn continuously, in
which case the means for producing the intermittent or interrupted motion would not
be made use of. Instead of the sliding ram shown and described I might use an inclined
or curved or spiral plate or series of inclined plates formed with or fixed to a central
shaft which is revolved intermittently or continuously so as to force the coal forward
into the retort by the screw or wedge like action of the said spiral or inclined plate or
plates. On sheet 11, Figs. 37, 38 and 39 I have illustrated such an arrangement in
which a spiral blade 14 is fixed to a shaft 15 which is actuated either manually or
mechanically so as to revolve and force the coal which is delivered through the
opening 16 into the retort and in the direction of the arrow by the action of the
blade 14.
In sheet 1, Figs. 1. 2. 3 and 4 I have described and illustrated branches R as
leading the coal from the hopper L to the upper retort of each set and allowing the
coal to fall vertically down past the mouth of the retorts each of which thereby receives
its share of the charge. To provide against possible objections to this mode of feeding
the coal to the retorts I have devised and have illustrated by Figs. 41 to 43 sheet 12
of the drawings an arrangement whereby each retort has a separate branch 17 leading
from a central shute or prolongation L' from the lower part of the hopper L. By
this means each retort mouthpiece has its own distinct feed branch and cannot
therefore be effected by any derangement in the feed branch of another retort. When
employed in the manufacture of gas it is preferable that the retorts should be of
fire-clay.
The hereinbefore described improvements or portions of them are applicable not
only to the manufacture of illuminating coal gas but also to the distillation in retorts
of vegetable or other substances and of minerals, as for example to the manufacture of
oil from shale.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
(1.) The general arrangement construction and combination of machinery and
apparatus or any mere modification thereof for continuously charging and discharging
retorts employed in the manufacture of illuminating gas from coal, or in the distillation
of gases, vapours and products from other matters, minerals and materials capable of
being so treated substantially as herein before described and as partly illustrated in the
accompanying 12 sheets of drawings.
(2.) In apparatus for continuously charging retorts, the ram H capable of sliding
backward and forward and actuated by a rack and pinion or other suitable means and

page_text: automatically operated by power so as to feed successive charges of coal or other
material into a retort by the means and substantially as and in the manner hereinbefore
described and illustrated.
(3.) In apparatus for continuously charging retorts the charging arrangement
illustrated on sheet 11 of the drawings and consisting of a spiral or inclined blade or
spiral or inclined blades carried on a central shaft and rotated so as to force the charge
forward into the retort substantially as described and shown.
(4.) In apparatus of the indicated nature for continuously charging and discharging
retorts the feed hopper L, closed at the top by a sliding door as in sheet 1 or by
revolving doors as in sheets 3 and 4 and from which the coal or material is conducted
to the retorts by vertical branches It as shown in sheet 1 or by inclined shutes or
branches 17 as shown in sheet 12 substantially as described and shown.
(.) Operating the charging ram or rains by means of excentrics, cams, elliptical
wheels or cranks driven by power, in the manner and substantially as described and
shown.
(6.) The mechanism for operating the charging ram or rams consisting of a
revolving shaft S worm or worms W worm-wheel X cam or cam groove Z, lever a
and link c, clutch dd', excentric e and rack f arranged and acting substantially as
hereinbefore described and shown on sheets 1 and 5 of the drawings."
(7.) The arrangement of mechanism for operating the charging ram or rams from a
crank or crank dise and consisting of the revolving shaft 2 worm, worm wheel 3
carrying a finger to operate the lever and clutch 5; the pinion 1 spur wheel the
latter having an incline to throw the clutch lever and clutch out of gear, the
intermediate shaft and the crank or crank disc all arranged and operating
substantially as described and shown on sheet 7 of the drawings.
(8.) The cam 6 and mechanism for operating the charging ram or rams therefrom
substantially as described and shown on sheet 8 of the drawings.
(9.) The mangle motion for operating the charging ram or rams substantially as
described with reference to sheet 9 of the drawings.
(10.) The elliptical wheels 12 for imparting motion to the charging ram or rams
arranged and operating substantially as described and shown.
(11.) In apparatus of the indicated nature for continuously charging and dis-
charging retorts, the trunk i for receiving the spent coke or other material in
combination with the hinged or sliding door at the foot of the trunk and applied and
acting substantially as hereinbefore described and shown.
Dated this 31st day of August 1888.
DUTTON & FULTON,
1, St. James Square, Manchester,
Agents.