IMPROVEMENTS IN THE PREPARATION OF FUEL, AND IN APPARATUS FOR SUPPLYING THE SAME TO FURNACES
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Baxter House, Old Saint Pancras Road, in the County of
Middlesex, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twentieth day of
September, One thousand eight hundred and forty-nine, in the thirteenth year
of Iler reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Henry Bessemer, my exors, adiñors, and assigns, Her especial
license, full power, sole privilege and authority, that I, the said Henry
Bessemer, my exors, adiiiors, and assigns, or such others as I, the said
Henry Bessemer, my exors, adñiors, or assigns, should at any time agree with,
and no others, from time to time and at all times during the terin of years
therein expressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, my Invention
of "IMPROVEMENTS IN THE PREPARATION OF FUEL, AND IN APPARATUS FOR SUPPLYING
THE SAME TO FURNACES;" in which said Letters Patent is contained a proviso,
that I, the said Henry Bessemer, shall cause a particular description of the
nature of my said Invention, and in what manner the same is to be performed,
by an instrument in writing under my hand and seal, to be inrolled in Her
said Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said in part recited Letters Patent, as in
and by the same, reference being thereunto had, will more fully and at large
appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Henry Bessemer, do hereby declare that my said Invention consists,-
Firstly, of so heating small coal as to soften the same as to admit of its
being compressed into blocks or forms without requiring other cementing
matters. This part of my Invention also consists in certain combinations of
machinery for pressing, solidifying, and forming fuel into blocks or masses,
and in apparatus for preparing small coal or coal dust as fuel, in which appa-
ratus the fragments of coal are fused or softened by heat applied thereto in
various ways, and afterwards subjected to pressure by the said machinery while
in a partially fused or softened state, whereby the said fragments of coal are
made firmly to cohere and form a dense mass, without the necessity of the
admixture of any foreign adhesive matters therewith.
Secondly, my Invention consists in preparing fuel of different qualities from
coal or coal dust, by separating therefrom different quantities of their gaseous
or volatile constituents, and in some cases also of further altering and
modifying the quality of the fuel by the admixture of different kinds of coal or
coal dust, so as to render such fuel peculiarly adapted to the various circum-
stances and conditions under which it is to be used.
And, lastly, my improvements consist in supplying fuel to furnaces by a
combination of revolving circular fire bars or wheels, which conduct the fuel
into the furnace and progressively move it therein, and finally eject the
clinkers or slag at the opposite end of the fire chamber.
Before describing the details of the plans referred to under the three heads
just mentioned, I will briefly point out some of the most prominent defects of
the various compounds hitherto proposed or manufactured as fuel, in order that
the distinctive character of the present Invention may be more fully under-
stood. In the manufacture of fuel composed partly of small coal or coal dust, a
great variety of matters, such as tar, pitch, resin, oil, clay, lime, asphalte, gutta
percha, Roman cement, &c. &c., have hitherto been used in order to cement
the coal dust together, and both heat and pressure have sometimes been used
separately or together to facilitate the aglomeration of the heterogeneous mass.
From this admixture of foreign matters with the coal numerous disadvantages
arise. In some cases the fuel is rendered expensive by the use of materials
much more costly than coal. Many of the materials used are wholly incom-
bustible, and thereby add to the weight and bulk of the fuel, while they check
its combustible properties, and add materially to the slagging or clinkering of
the furnaces in which they are used. The use of gas tar or like materials
very
much increases the production of dense black smoke, and when used in
large quantities cause the fuel to soften or liquify in the furnace to such an

page_text: extent as to prevent the free passage of atmospheric air through the mass, the
absence of which produces an imperfect combustion, accompanied by a dense
black smoke. Many of these mixtures have a very offensive odour, while
nearly all of them are but feebly. coherent, and are broken into small fragments
by a fall or a light blow. The object of the first part of my Invention is to
remedy these defects, by producing a prepared fuel from coal or coal dust,
without the necessity of the admixture of any foreign matters therewith. It
is found that when coal or coal dust is heated up to a temperature of about
five hundred or six hundred degrees Fahrenheit, it becomes softened, the
bituminous portions undergoing a degree of fusion sufficient to cause the small
pieces to adhere together. It is this peculiar property of partial fusion in coal
that I make use of as a means of forming by pressure consolidated blocks or
masses of coal, possessing the characteristic properties of the coal from which
they are formed, but which have the advantage of being in pieces of uniform
size instead of in the usually irregular state of coal. I would observe, that
instead of forming the soft coal into large unwieldy masses (as usually prac-
ticed in the manufacture of artificial fuel), and which require to be broken
into pieces before use, whereby much small coal or dust is again produced, I
prefer to make them at once into small cylindrical pieces, of a size best adapted
to furnaces or domestic use, according as required, whereby the trouble and
loss of breaking is prevented, and a most convenient fuel obtained. The
machinery or apparatus wherewith this first part of my Invention may be
carried into effect is represented on Sheet A of the Drawings hereunto
annexed; where Figure 1 is a longitudinal elevation of a furnace, and an end
elevation of pressing machinery; Figure 2 is a plan of the same; Figure 3 is
a longitudinal section of the furnace on the line A, B, of Figure 2; Figure 4
is a cross section of the furnace and longitudinal section of the pressing
machinery on the line C, D, of Figure 2; Figure 5 is a side elevation of the
pressing machinery, and an end elevation of the furnace; and Figures 6 and 7
are details of the travelling chain bed, on a larger scale. In this apparatus,
the furnace for heating and softening the coal, the machinery for pressing it,
and the steam engine which produces the required motive power, are all
combined, and constitute one apparatus; and as the products of combustion
will pass off from the furnace at a high temperature, it is intended that
this surplus heat shall be applied to the generation of the steam required
by the engine, for which purpose a steam boiler provided with suitable flues
should be set as near as convenient to the end a* of the furnace a, where it
will be perceived that an opening is left at b, for the purpose of allowing the
heated matters from the furnace a to pass into the flues of the steam boiler,

page_text: the arrangement of which is so well understood as not to require any detailed
description here. The furnace a is of the reverberatory kind, and has a fire-
place at c, provided with fire bars d and doors e. f is an endless chain bed, of
peculiar construction, passing over polygonal drums g, mounted on axes h; the
horizontal position of the chain f is insured by small iron rollers i, which
support it at short intervals. The rollers i are provided with axes, which work
in iron sockets let into the side walls of the furnace, as does also the axis h* of
the polygonal drum 9. The chain bed consists of a number of iron bars, of
about thirty inches in length, notched on each side, and fitting into each other
in a similar manner to a common hinge joint, and, like the hinge, it has a pin
passing entirely through it, and thus forms a joint capable of folding over the
polygonal drums g, and also of presenting a nearly flat surface on the upper
side, see Figures 6 and 7, where a part of the chain bed is shewn on a larger
scale. Near the end of the furnace farthest from the fire there is fixed a hopper
j, into which the small coal is thrown; this hopper has a roller k, with leaves
projecting from it, working in a cylindrical part formed in the hopper. The
roller is mounted on a shaft 7, which turns in bearings formed in the bosses
cast on the sides of the hopper j. The shaft is further supported by a plummer
block n, and carries on its outer end a drum m, which receives motion from
the strap o, and causes a regulated quantity of the small coal to pass from the
hopper through the opening p, and fall upon the endless chain bed in a thin
layer; the motion of the chain bed in the direction of the fire-place c will bring
the coal along with it, and discharge it into the hopper 1. To prevent any
portion of the coal that may stick to the chain from being carried back again,
a scraper s is made to press its edge against the lower part of the chain; the
scraper is mounted on an axis, and has a lever and ball q, the weight of which
presses the edge of the scraper against the chain. It will be seen that the fire
bridge t rises sufficiently high to proctect the chain from the violent action of
the fire, and it at the same time forms one side of the hopper or rescéptacle r.
I have shewn a break in the Drawing, to denote that the furnace and chain bed
are to be made longer than is there represented; from thirty to forty feet of
bed will be found to answer well. When a fire is made in the fire-place c, the
heat will be reverberated on to the thin stratum of coal upon the chain bed,
which, as it first enters from the hopper, will be subjected to the lowest
temperature of the furnace, and will be brought progressively into the hotter
part near the fire bridge, while new portions of coal will be deposited upon the
chain bed as it passes under the hopper j, which will in turn be carried
towards the fire bridge; the increased temperature to which it is thus subjected
will cause the coal to soften, and commence to give off some of its volatile

page_text: constituents, which will inflame and add to the action of the furnace. The
extent to which the fusion of the coal is carried may be regulated by the speed
at which the chain moves, and also by the state of the fire. The small coal being
thus softened by heat, and delivered in a regular and continuous stream into
the hopper,r, is then to be pressed by an apparatus constructed in the following
manner-A is a strong bed plate or frame, forming a sort of rectangular box,
having a flange A¹ extending around the upper side, and another flange at the
lower side, connected to the upper one by ribs A2, and dividing it into pannels
externally. Upon the upper flange of the bed plate are bolted the plummer
blocks B, which support the trunnions of an oscillating steam cylinder C, which,
with its steam pipes, slide valve, and valve gear, may be constructed in the
ordinary way. D is a one-throw crank of great strength, working in plummer
blocks E, and carrying on one end the fly wheel F. The piston rod G of the
steam cylinder is connected to the crank by a gib head G*. There is also
connected to the same crank-throw a connecting rod H, having a double gib
head, so as to take hold of the crank on each side of the piston rod G; the
other end of the connecting rod H is jointed at H* to the cross head I, which
moves in slots formed in the guides J, J, which are bolted to the upper flange
of the bed plate A. One end of the bed plate A passes through the lower part
of the furnace a, and has bolted to it at that part a massive piece of iron K,
with two cylindrical holes bored entirely through it, parallel to each other, and
which for distinction I term the pressing cylinders; the piece K is held firmly
in its place
bolts, and is further prevented from moving by projecting pieces
K*, which abut against the flanges of the frame A. The upper side of the
piece K has an opening or hopper *, through which the softened coal falls
into it. There are two plungers L, L, fitted to the cylinders, and keyed into
the cross-head I, so that the revolution of the crank by means of the con-
necting rod H and guides J, J, will produce a reciprocrating motion of
the plungers L, L. The crank D has keyed upon it at one end a bevilled
pinion M, working into a bevilled wheel N, which is mounted on a shaft P,
supported by plummer blocks Q, Q; and at the other end of the shaft P there
is a spur wheel R, in gear with another wheel S, on the axis of the polygonal
druni g; this axis h also carries a drum T, over which the strap o passes,
and communicates motion to the roller K, and thereby regulates the supply of
coal upon the chain bed. The action of the apparatus will be as follows:--
Steam having been got up in the boiler by a fire made temporarily under it
for that purpose, and the fire lighted in the fire-place c, the working of the
apparatus will commence whenever a communication between the boiler and
steam cylinder is opened. The rotation of the crank shaft will put in motion

page_text: the bevil wheels M and N and the shaft P, and by means of the spur wheels
R and S, the shaft h of the polygonal drum 9 will receive a rotatory motion
much slower than the crank shaft, by reason of the difference in the diameter
of the wheels made use of for that purpose, and thus a slow travelling motion
will be given to the chain bed. The shaft H also carries a drum T, which by
means of a strap gives motion to the drum m and feeding roller k, and thereby
causes a regular supply of small coal to fall upon the chain bed; as it passes
under the hopper, the reverberated heat from the crown of the furnace acting
on the thin stratum of coal upon the bed, will cause a partial fusion or
softening of its bituminous parts before arriving at the hopper r, into which it
falls. While this action is regularly and continuously going on, the crank shaft
of the apparatus will, by means of the connecting rod H and cross-head I,
give a reciprocating motion to the plungers L, L, which work in the cylinders
K, and pass along the lower part of the hopper r*, and push before them the
softened portions of coal into that part of the cylinders marked K'; the extreme
distance to which the end of the plungers move is indicated by the letter Z.
When the crank commences its backward movement the plungers will also
recede until they assume the position represented in the Drawing; while this
retrogade movement of the plungers is taking place some portions more of
softened coal will have fallen down from the endless chain bed, and have been
deposited in the hopper and upon the plungers; but as the plungers recede,
as before stated, into the position shewn in the Drawing, the coal which has
fallen upon them will fall off again into the space occupied by them, and
when the plungers again advance, a fresh portion will be forced into the
cylinders K¹; but as the plungers move forward an equal distance each time,
the portion of coal pushed forward will be forced against the portion of coal
left there by the former stroke of the plungers, and not only will it be forced
against it, but it will move it further along the cylinders K', until.the.last
portion occupies the place of the former one, and thus, by the continued
action of the plungers, fresh portions of coal will be forced into the cylinders
K'. It will be observed, that the cylinders K' are open at the end, and it is
towards this open end of them that each successive portion of coal is forced by
the plungers. The friction of the mass of coal in sliding along the cylinder
is very great, and the resistance thus opposed to the motion of the plungers
L, L, causes a powerful compression of the fuel to take place, which is finally
projected from the end of the cylinders in a solid and compact state, as shewn
at W. I have before stated that the surplus heat of the reverbatory furnace
may be applied to the production of steam for supplying motive power for the.
working of the apparatus, and in some cases it may be deemed advisable to so

page_text: far heat the coal by this process as to fire it and cause a combustion of the
more volatile portions thereof, by which more heat will be given off to the
boiler, and a fuel will be produced possessing many of the peculiar and valuable.
properties of coal, but at the same time not possessing sufficient bituminous
matter to cake together when used in a furnace or common fire-place, and
from the same reason not producing a dense black smoke, and may be used
in many cases where coke is now employed. Although I have here stated
that a fuel differing from coal in several respects may be produced by this
apparatus, I wish it to be understood that I prefer to employ the apparatus
hereafter described under the second head of my Invention for that purpose,
and to use the apparatus herein-before described chiefly for the production of
a fuel composed wholly of coal, and acted upon only as much by heat as is
necessary to cause a firm adhesion of the particles when a powerful pressure
is brought upon it in the heated state.
Secondly, with regard to my improvements in preparing fuel of different"
qualities from coal or coal dust, by separating therefrom different quantities
of their gaseous or volatile constituents, and in some cases also of further
altering and modifying the quality of the fuel by the admixture of different
kinds of coal or coal dust, so as to render such fuel peculiarly adapted to
the various circumstances and conditions under which it is to be used:-
From what has been said under the first head of my Invention, it will have
been perceived that the main object there aimed at was the production of
solidified cylindrical lumps of coal, little being abstracted from it during the
process of manufacture, and therefore producing a fuel possessing the general
characteristics of the coal from which it was formed; but as there is no kind
of coal which possesses in its natural state all the qualities desirable in fuel, I
have endeavoured to supply this desideratum partly by the purification of coal,
by driving off some of its volatile products, and partly by the admixture of
coals of different qualities, by the blending of which several kinds of fuel may
be produced having different properties, and peculiarly adapted to furnaces of
various kinds. I have before shewn how the softening of the coal is effected"
by heat, and it will be readily understood how, by continuing the heat for a
greater length of time, or using a higher temperature, that a portion of the
fuel will be volatilized and pass off in the gascous form. If a small quantity
only of these volatile products are driven off two very important results will
follow: Firstly, the fuel when thrown on the fire will not give off those dense
volumes of black smoke which raw coal does, because no more gaseous matter
will be given off then the quantity of oxygen in the furnace will consume; and
secondly, the coal being thus deprived of a part of the tar, &c. will be inuch

page_text: less fusible than raw coal; and therefore, instead of caking over the top of the
fire, and, preventing the passage of air through the fuel, as the raw coal does,
the regular, sized cylindrical lumps will to a great extent maintain their shape,
and allow a free passage of air to play between them, by which means a vivid
combustion will be kept up, and the formation of dense black smoke will be
for the most part, if not wholly, avoided. In order to render fuel thus pre-
pared suitable for locomotive engines, and other purposes requiring similar
fuel, I carry on the process of volatilization to a much greater extent, varying
from one-third to nearly all the gaseous matter contained in the coal. The
limit to which this process is carried should always be such that the coal is not
rendered so dry or hard as to prevent its cohesion in the pressing cylinder;
but in order to obtain these volatile products from coal with as little heat as
possible, and also to facilitate the formation of the fuel into a dense and
compact mass, I sometimes use an air pump, and form a vacuum or partial
vacuum in the retorts or vessels in which the coal is heated, so that the
gaseous matters are more freely liberated; and being thus carried off from the
pores, cells, or interstices of the fuel, the mass is more readily pressed in
the cylinder, and its density and solidity greatly increased, and is therefore in
the most favorable condition for burning in furnaces having a powerful blast;
and from its great density and regularity of form, it is well adapted for stowage
where space is of consequence. The volatile products resulting from the fore-
going processes may be passed through water, by which a part will be condensed
and may be applied for various useful purposes, and the remaining inconden-
sible portions may be conducted through pipes and burnt beneath the retorts;
or it may be conveyed to a gasometer, and supplied as fuel for generating steam,
or other purposes, and also to be used for purposes of illumination. In certain
localities (Staffordshire, for instance,) where ceal is found which produces a
white dusty ash, it is desirable to prevent or modify this defect by the admix-
ture of another description of coal, such as that found at Newcastle-upon-Tync,
and known as caking coal; equal quantities of these coals mixed together,
softened by heat and pressed in the manner herein-before first described, will be
found to produce an excellent fuel, burning more freely than the Newcastle,
and avoiding the dusty white ash of the Staffordshire coal; and also anthracite
coal mixed with varying proportions of Newcastle caking coal will be found to
produce a valuable fuel when treated and combined in the manner herein
described; but as these different qualities of coal for mixing will be very much
governed by local circumstances, I need not further particularize their use
than by saying generally that in those cases where a particular property or
quality is deficient in one description of coal, and is possessed to an undue

page_text: extent by any other kind, their union into one mass will be to the advantage
of both. In order that the volatile products of coal given off while undergoing
the softening process, as well as those portions which are purposely expelled
for the purpose of modifying the quality of the fuel, and also.in order that the
lumps of fuel may be made of definite lengths, I construct an apparatus in
which the retort furnace for heating the small coal, the pressing machine for
solidifying the fuel, and the engine for producing the motive power, are com-
bined so as to constitute one apparatus, and which is represented on Sheet B
of the annexed Drawings; where Figure 1 is a longitudinal elevation, with the
steam cylinder omitted; Figure 2 is a plan of the same; Figure 3 is a longi-
tudinal section on the line A, B, of Figure 2, and shewing the position of the
steam cylinder; Figure 4 is a longitudinal section on the lines C, D, Figure 2,
and E, F, Figure 3; Figures 5, 6, 7, 8, and 9 shew sections of the pressing
apparatus in different stages of the pressing process. In the furnace a is fixed
the rectangular vessel or retort b, which is shewn broken through, to indicate
that its length should be greater than represented in the Drawings; about thirty
feet in length will be found to answer well. It should (for convenience of putting
up) be made in three lengths, united by flanges, and the joints made tight with
iron cement. One end of this retort projects from the furnace, and overhangs
a part of the pressing apparatus. The retort has a partition b', extending nearly
the whole length of it, and in a tangent line with the upper surface of the
polygonal drums c and d, over which two endless chains e and f are made to
pass (see Figures 2 and 3); the chains c and d are connected together by broad
plates of iron g, with flanged ends, which are rivetted at h to the single links
of chains; the edge of the plates g which project beyond the chains is bevilled,
so as to form a scraper. The polygonal drums c and d have projections i
formed upon them, which fall into the spaces between the double links of the
chains, and insure the motion of them when the drums c and d are turned
round. On the upper side of the retort there is fixed a hopper j. The lower
part of the hopper in which the coal dust or small coal from which the fuel to
be formed is placed is made to fit closely to the leaves or ribs projecting from
the feeding drum k. There are bosses / formed on the sides of the hopper, in
which the shaft n of the feeding drum revolves. There are also bosses (not
seen in the Drawings,. formed on each side of the retort for the axis of the
polygonal drum c to revolve in, and on the outer projecting part of the retort
are formed two other bosses o and p, for the axis r of the polygonal drum d to
revolve in; one end of this axis is elongated, and passes through a stuffing box
formed on the boss p, so that none of the volatile matters within the retort can
make their escape at the part through which motion is transmitted to the

page_text: interior. The action of this part of the apparatus is as follows:-A fire having
been lighted in the fire places, the heat and products passing along under the
retort will make their exit at the open end of the flue s', where they may be
made to circulate about a steam boiler, for the purpose of generating the motive
power required to work the apparatus. It will be preferable to set the retort
so that the heat may ascend' a narrow space between the sides of it and the
brickwork of the furnace. I have shewn an enlargement of the fire chamber
ats, for the purpose of transmitting radiant heat to the under side of the pro-
jecting part of the retort. 'The temperature of the furnace having brought the
retort up to a heat approaching redness, the feeding drum is put in motion,
when the small coal or coal dust will be deposited upon the shelf ; but the
motion, of the chains and scrapers in the direction indicated by arrows will
move it along the shelf, and as each scraper comes in turn under the feeding
drum, the coal which has fallen between each of them will be carried forward
to the end of the shelf 6*, off which it falls on to the lower and hotter part of
the retort, and, as before, occupies the space between the scrapers. It will be
observed that the entire weight of the chains and scrapers rest on the bottom
of the retort, so that by their constant passage over it the coal is prevented
from sticking to it, and rendering its interior surface uneven. The action of
the scraper will not only impel the coal forward, but will so turn it over as it
passes along as to present fresh portions of it to the heated surface of the
retort, and thus insure an equal effect on the whole of the coal dust thus acted
upon, and the same will become softened, and in that state will be moved over
the opening in the lower side of the retort, and fall into the receptacle t,
where it will become operated upon in the manner about to be described. A
is the foundation plate or framing of the pressing apparatus; it is a sort of
shallow box, having a flange A¹ around its upper edge, connected to the lower
flange by vertical ribs A2, which divide it externally into pannels; the interior
portion of the framing being also divided by ribs A, by which its strength is
increased. Upon the flange A¹ is bolted the plummer blocks B, which
the crank shaft C, which is made very strong, to withstand the strains to which
it is subjected. The crank has but one throw formed on it, in the centre'
of which is attached by a gib head D the piston rod E of the oscillating
steam cylinder F. The steam cylinder, with its induction and eduction"
pipes, slide valve, and other necessary appendages, may be constructed in
the usual way, and therefore do not require any detailed description; and
as these parts, if represented in the Drawings, would obscure others more
necessary to be seen, I have omitted them in all the Figures, except in
Figure 3, where the steam cylinder is represented in the position it would
support

page_text: occupy at the particular part of the crank's motion there represented. It will
be observed that the steam cylinder is placed with its axis in a line vertically
over the crank shaft, and is there supported by trunnions G, as usual, working
in plummer blocks bolted to the two frames H, H; these frames have lugs
cast on them at H*, through which stretchers are to pass in order to steady
them. The frames H are bolted at foot to the flange A of the bed plate, in
order to regulate the motion of the apparatus. The fly wheels I, I, are keyed
one on to each end of the crank C. A stout connecting rod J is made with a
double gib head J* to embrace the gib head D, and thus to receive motion from
the same crank throw. The other end of the connecting rod J is jointed by a
gib head and pin to two lugs K*, which project from the stout cross-head K.
The ends of this cross-head slide in guides L, L, which are secured by bolts to
the flange A of the bed plate. There are three plungers M, M, M, keyed
into the cross-head K, and work in cylindrical holes bored truly through the
massive block of iron 'N.. This block N' is bolted to the bed plate by a flange
N*, and is keyed up between steps, cast on the bed plate. The upper part
of the cylinder block N' has a large opening N¹ made in it, through the
bottom of which the plungers M move, and inmediately over the opening N
is the receptacle into which the softened coal falls from the retort. The
cylindrical holes in the block N have another set of plungers P, P, P, working
in the opposite end of the holes to that occupied by the plungers M, M, M.
On the flange A' of the bed plate are bolted two guide bars Q and R, having
holes bored in them of a size to fit the plungers P, P, P, which are made long
enough to work through both these guides, so that when the plungers P; P, P,
are entirely withdrawn from their respective cylinders in the block N, they
will be so guided is to re-enter them without difficulty. The plungers P, P, P,
are keyed to a cross-head S. "On the ends of the cross-head S'there are fitted
with gib heads two long' connecting rods-T (see Figure 2, as they are omitted
in the rest of the Figures to prevent obscurity of the other parts). The opposite
ends of the connecting rods T are provided also with gib heads, and work on
crank pins U, which project from one of the arms of each fly wheel I, I.
These crank pins U, U, are so placed with reference to the central crank
throw C, that the latter forms an angle of forty-five degrees to the crank pins,
that is, the one is one-eighth part of a circle in advance of the other, and thus
the action on their respective plungers will be such that they will alternately
approach and recede from each other at each end of their respective strokes.*
I have before described how the small coal is made to traverse the retort;
and be deposited in the receptacle. The means whereby the requisite
motion is given to the chain and feeding drums is as follows:-Over one;

page_text: of the fly wheels I a strap is passed, which works upon a drum V on the
shaft W. On this shaft W there is a worm X, which works on the upper
side of the worm wheel Y, which is keyed on to the shaft of the poly-
gonal drum d; the shaft W also carries another worm 1, which works into
the lower side of the worm wheel 2, keyed on the axis n of the feeding
drum. The shaft W is supported in bracketed plummer blocks 3, 3, which
project from and are bolted to the side of the retort, so that whenever the
fly wheel is put in motion the intermediate wheels and shaft last described
will transmit the requisite motion to the scrapers and feeding drum, as before
described. From what I have already said, it will have been understood
how the steam piston acting upon its crank will put in motion the whole
apparatus, which will be regulated by the fly wheels, and in what manner
the cross-heads K and S will be acted upon by their respective connecting
rods, and how the set of plungers M, M, M, and plungers P, P, P, are made
to reciprocate in their respective ends of the block N; but lest the way in
which they are made to approach and recede from each other be not already
understood, I have given five sectional Figures on Sheet B, by which the
relative positions of the two sets of plungers with reference to cach other
at different parts of their stroke will be seen. And to render this explana-
tion more clear, let us suppose the operation to commence when the crank
throw C and its connecting rod are in a horizontal position, and the plungers
M, M, M, withdrawn as far as possible from the block N: this position is
represented in Figure 5, where it will be seen that the fuel in an uncom-
pressed state has fallen down, and occupies the space in the front of the
plungers M: if we now make one-eighth part of a revolution, the plungers M
will be moved forward a little, as shewn in Figures 6 and 3, where it will be
seen that the crank pins U, U, have risen up to the horizontal line, and
brought the plungers P nearer towards the centre of the block N: if we now
give another eighth of a turn to the crank, the plungers N will have advanced
a considerable distance, being at half stroke, and at the same time the plungers
P will have receded into their starting position, as represented in Figure 7.
Here it must be observed that the soft coal which was carried forward by
the plungers M is compressed between the opposing ends of the two sets of
plungers. In this position of the plungers there is a small space at Z, Figure 7,
where any surplus quantity of coal may squeeze out before it is made to enter
the close part of the cylinder, after which they will approach a very little
nearer to each other, and thus give the final pressure. If another eighth of a
revolution is now made, the relative positions of the crank and crank pins will
give a quicker motion to the plungers P, which will commence receding from

page_text: the other plungers M, and thus leave no pressure on the solidified lump of
coal X. Were not the pressure thus relieved, the lump of coal as it merges
from its cylindrical hole in the block N would be broken, there being no
longer any circumferential support for it. This position of the apparatus is
shewn in Figure 8. Another eighth of a turn will complete a single stroke of
the plungers M, and have entirely expelled the block of coal X, which is
represented as falling down in Figure 9; the plungers P have receded still
further, and allow ample space for the block of fuel to fall. Another eighth of
a turn will commence the return stroke of the plungers, and by following on in
the same way until one complete revolution is performed, the respective plungers
will again have resumed the position represented in Figure 5, and be ready to
renew the operation. If three plungers are made use of, as here represented,
three blocks or cylinders of fuel of equal length and diameter will be formed
at each complete stroke of the engine. As there is a tendency in the block of
fuel to stick to the plungers M, I have placed a detaching frame at the end
of the machine where the blocks are expelled. 4, 4, are thin bars of iron, fixed
on an axis 5, the ends of which work in lugs 6, on the guide bar R. The other
end of the bars 4, 4, are connected together by a rod 8, and upon the cross-
head S there are bolted two small frames 9, 9, which carry rollers 10; upon
these rollers the bars 4, 4, rest, and when in the position shown in Figure 3,
the bars are supported a little distance above the plungers P; but when the
cross-head S moves backward, and allows the blocks of coal to be projected
outward by the plungers M, then the roller will pass under the inclined part
of the bars 4*, when they will descend by their own weight, and the rod 8
will come in contact with the blocks of coal, and detach them from the
ends of the plungers; if they should adhere, the reverse motion of the
cross-heads will again raise up the bars 4, in readiness for a repetition of
the process.
From what has been before said in reference to the softening process by heat,
it will have been understood that the coal dust may be made to traverse the
shelf, where it will receive a preparatory heating, and afterwards traverse
the bottom of the retort so quickly as only to produce such a slight effect
upon the bituminous portion of the coal as only to soften it a little, and render
it fit for the operation of compressing it into solid lumps, possessing the general
properties of the coal from which it was produced. But one of the great
objects of this apparatus is to alter and modify the composition of the resulting
fuel by driving off certain of the volatile constituents of coal, and thereby
rendering such fuel more fitted for certain processes in the arts than ordinary
coal. To effect this object, the speed of the feeding drum and polygonal drums

page_text: may be regulated so as to subject the coal to any assigned period of operation,
and also the intensity of the fire being regulated, the extent to which the dis-
tillatory process is carried with be under perfect control, and the gaseous
matters given off from the coal as it passes into the hottest part of the retort
over the, fire-places will have to pass over the surface of the coal which is
advancing in that direction, and will help to heat it, and will also assist in
transmitting heat to the under side of the shelf b¹; it will ascend through the
opening 6, and pass along over the coal dust spread upon the shelf, and
further. assist in heating it, and finally make its escape through the pipe u.
This pipe should have an elbow, descending in the manner usually practiced in
gas works, and known as the hydraulic main. In this vessel the liquifiable
portion of the volatile matters will be condensed, and the gas may be passed
into a gasometer, where it may be stored and used. The fuel resulting from
this partial distillatory process will be found to be less fusible in the furnace
than ordinary raw coal, and consequently the caking in the furnace will be
prevented.
I have before described and represented on Sheet A a method of heating
coal and compressing it differing from that herein last described and repre-
sented on Sheet B, and it will be obvious that either of the heating apparatus
may be combined with either of the pressing apparatuses instead of the
combination herein given.
In order to facilitate the evolution of gaseous matters from the coal at as
low a temperature as possible, and to increase the density of the compressed
fuel; I use an air pump, constructed in the manner generally employed for
exhausting sugar vacuum pans, and which is well known and understood. I
connect the pump with the pipe u, Sheet B, and by the application of steam
or other motive power I keep the retort in a state of exhaustion, which
should if possible be equal to twenty-four or twenty-five inches of mercury in
the barometer. The effect of this exhaustion is to cause the liberation of the
gas from the cells and interstices of the fuel, and to render it more dense and
compact when pressed. When the air pump is used as before stated, the
eduction valves must be made to communicate with the hydraulic main, so
that the gaseous matter's pumped out may pass off into the gasometer, as
before described. And further, instead of applying fire direct to the under
side of the retort, as shewn in Sheet B, I use highly heated steam for the
purpose of heating and softening coal to be afterwards pressed into lumps
or cylindrical pieces. For this purpose, a set of cast-iron pipes, arranged
in a furnace in the same way as is now commonly used for heating air
for hot blast furnaces, and also for heating steam for various purposes,

page_text: Into one end of this series of heating pipes the. waste, steam of the engine
is allowed to pass, and the pipes being kept at a red heat the steam will
acquire a very high temperature, and in that state is. to, be supplied to the
interior of the retort, for, the purpose of softening the coal.. In. this, case
the retort, which may be made in the same manner as that represented in
Sheet B. but will not require any fire-place or fluc beneath it, but should
be enclosed in brickwork or other bad conductor of heat; the pipe which
conveys the steam should enter at the hopper t, where the soft coal' falls into
and finds its escape with the gases through the pipe u into the hydraulic
main, where condensation will take place, while, the gas passes off to the
gasometer. I am aware that the use of heated steam, has been.proposed for
manufacturing coke, and for heating certain mixtures of pitch, tar, coal dust,
&c.; I therefore do not claim it for those purposes; but what I consider new
and of my Invention is, the application of highly heated steam for the purpose
of softening coal, in order that it may be formed into a solid mass by pressure,
and without requiring the admixture of any cementing, material or foreign
matter therewith.
Lastly, with regard to my improvements in supplying fuel to furnaces
by, a combination of revolving circular fire bars or wheels, which conduct
the fuel into the furnace and progressively move it therein, and finally
eject the clinkers or slag at the opposite end of the fire chamber:-
Numerous plans for feeding furnace fires regularly with small, coal and for
consuming their smoke have been brought forward and used with more or
less advantage, but there are still some particulars in which the present plans
are deficient. In some of them the fire-place is shut up, so as to render it
difficult to light the fire or to get at it in case of accident; most of them retain
the fire bars too long in contact with the hot fuel, by which they become
rapidly destroyed; while in other cases the complexity of the structure renders
it liable to frequent derangement, and is also a very expensive apparatus. In
order to avoid these disadvantages, I construct an apparatus as represented
on Sheet B of the Drawings hereunto annexed; where Figure 1 is a front
elevation of a steam boiler furnace to which this apparatus is applied; Figure 2
is a longitudinal section on the line A, B, of Figure 1 Figure 3 is a vertical
cross section on the line C, D, of Figure 2; Figure 4 is a sectional plan on
the line E, F, of Figure 2; and Figures 5, 6, and 7, enlarged views of one of
the wheels. That part of the apparatus which answers the purpose of fire bars
consists of a number of thin flat wheels, with a projecting boss cast on one side
of them, the thickness of which regulates their distance, apart from each other.
In all cases this boss should a little exceed the thickness of the rest of the

page_text: wheel, so that when any number of them are placed next to each other on a
shaft a sufficient space is left between them to allow another similar set of
wheels to pass in between their intermediate spaces, as represented in the
Drawings; where a is a rectangular cast-iron frame, having a flange a
extending around three of its sides, and in front is carried up higher at a', and
there forms a sort of dead plate to the furnace. The front of the frame a is
pannelled, and projects forward as far as the face of the two piers b, b. On the
sides of the frame a are cast the bosses c, which are bored through, and form
the bearings for the shafts d, which carry the "wheel grate;" these shafts d
have a feather made along them, so as to insure the revolving of the wheels e
with the shaft. When the shaft is put into the frame a, and its wheels
placed upon it, the collars m and n are fixed in their places by a cross pin; the
wheels e, which answer the purpose of fire bars, having been fixed, the worm
wheels g and h are keyed on to the shafts d. These wheels are so made that
they may all work into worms placed below them on the shaft f; but as their
diameters are too great to allow of them all working in the same line, I have
keyed on the three wheels g to their respective shafts in a line, and put the
two worm wheels h further along their shafts, so as to run clear of the
wheels g. It will be observed that these wheels are made with a slight
curved bevil in such a way that they can work on either side of the centre
of the worm shaft f (see Figure 2). The wheels g. are driven by three
worms i, and the wheels k by two other worms, which are not seen,
because the bosses h* of the wheels h obscure them. The end of the shaft f
which projects from the front of the furnace, may be provided with a wheel
or drum, according to local circumstances, by which motion may be transmitted
from the steam engine, and the worm wheels with their respective shafts and
grate wheels be made to revolve in a direction indicated by arrows. On the
wheels e, on the under side of that part of the frame a which forms the dead
plate, there are a number of pieces r, moving on a joint at s, so as to bear
freely down upon the wheels e* on the second shaft. These pieces serve to fill
up the interstices between the first set e', or feeding wheels, and form a con-
tinuation of the dead plate; but the wheels e, rising up through the pieces r,
will carry forward any fuel that may fall upon them; and thus the movement
of the whole of the wheels being in one direction, the fuel will be carried
forward and consumed. At the fire bridge there is a square iron bar p, extend-
ing across the furnace, and having a hole through it, for the circulation of
water; the clinkers that are carried to the back of the furnace can pass out
between this bar and the last set of wheels in the front part of the furnace.
I have left an arched opening t, of about the size usually made where

page_text: ordinary fire doors are used, and in advance of this a foot or so I nx the door
frame u and fire doors V, so that the fire may be looked at or supplied with
fuel with as much facility as in a common furnace if required at any time..
Above the door frame t there is placed a hopper W, having a feeding drum X,
with vanes or ribs extending along it. The axis y of this drum passes out
through the pier b, and there has a bevilled wheel a keyed on it, by which
motion may be transmitted, 'to it in any convenient way, and the supply of
small coal to the furnace regulated. To facilitate the removal of the frame a
and its wheels from the furnace, two long pieces or slides of iron B and C
are let into the side walls of the furnace; the piece B is made so as to receive
the side of the frame a and its projecting wheels; the back of the piece is
strengthened by ribs B', and along the side nearest the fire there is a small
flange, behind which the fire, lump E is placed, which protects the portion of
the iron work from any injurious effects of the heat. In Figure 1 is shewn a
plate G, which covers over the opening into this slide, and allows the worm
shaft fto pass out through it. . The iron slide C has also ribs C! cast upon it to
give it strength; and has a flange along the side nearest the fire,. to retain the
fire lump H in its place, so that the whole apparatus fitting into these two
fixed slides may at any time be taken out of the furnace and again replaced.
I have shewn on a larger scale at Figure 5 a side elevation of one of the
wheels,e, a section of it at Figure 6, and a side, elevation of it, at Figure 7.
Although I have herein shewn, as an example, the application of the combined
wheel grate to a steam boiler furnace, it is obvious that it will be equally
applicable to numerous other furnaces used for manufacturing purposes:
Having thus described the nature of my Invention, I desire it to be under-
stood that I do not confine myself to the precise details, so long as the
peculiar character of either part of my Invention be retained; but what I do
claim is,
First, the softening of small coals or coal dust by heat, and then forming it
into blocks or masses by pressure. I also claim the arrangement of machinery
for heating and compressing small coal or coal dust, represented in Sheet A.
Secondly, I claim the heating small coal or coal dust in retorts or close
vessels, so as to soften such coal, and then to form the same by pressure into
blocks or forms, whereby I am enabled to drive off and collect gaseous and
other products from the coal, and to modify the character of fuel produced
therefrom. I also claim the direct application of highly heated steam in such
manner as to soften small coal as a preparatory process, and then to form
the same into blocks or masses by pressure. I also claim the method or