IMPROVEMENTS IN SEPARATING COAL FROM FOREIGN MATTERS, AND IN APPARATUS FOR THAT PURPOSE
Year: 1851

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
COWPER, of 20, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Patent Agent, 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 Eighth day of December,
One thousand eight hundred and fifty-one, in the fifteenth year of Iler reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Cowper, my exors, adñiors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said Charles Cowper, my exors,
adiiors, and assigns, or such others as I, the said Charles Cowper, my exors,
adñiors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, and in the Islands of Guernsey, Jersey,
Alderney, Sark, and Man, and in all Her Majesty's Colonies and Plantations
abroad, the Invention of "IMPROVEMENTS IN SEPARATING COAL FROM FOREIGN
MATTERS, AND IN APPARATUS FOR THAT PURPOSE," communicated to me from
abroad; in which said Letters Patent is contained a proviso that I, the said
Charles Cowper, shall cause a particular description of the nature of the
said Invention, and in what manner the same is to be performed, by an
A

page_text: 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.
་
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Cowper, do hereby declare that the nature of the said Invention, and
in what manner the same is to be performed, are fully described and ascer-
tained in and by the following description thereof, reference being had to the
Drawings hereunto annexed, and to the figures and, letters, marked thereon,
that is to say:-
The Invention relates,
Firstly, to certain improvements in a method or methods of Separating
Coal from Foreign Matters, and Apparatus for that Purpose, described in the
Specification of Letters Patent granted to me for an Invention of "Certain
Improvements in the Treatment of Coal, and in Separating Coal and other
Substances from Foreign Matters; and in the Manufacture of Artificial Fuel
and Coke; and in the Distillation and Treatment of Tar and other Products
from Coal, together with Improvements in the Machinery and Apparatus for
the said Purposes," and bearing date at Westminster, the Second day of
November, One thousand eight hundred and forty-nine, which Specification
was inrolled in Her Majesty's High Court of Chancery on or about the
Twenty-ninth day of April, One thousand eight hundred and fifty.
Secondly, the Invention relates to an improved mode or modes of separating
coal from foreign matters by means of improved apparatus operating by the
action of a stream of water.
.
Coal in the state in which it is obtained from the mine is always more or
less mixed with foreign substances, such as carbonaceous schists, sulphuret,
oxide, and carbonate of iron, sulphates and carbonates of lime and mag-
nesia, and other substances, proceeding from the roof or walls of the mine,
or sometimes from small veins interspersed in the coal itself. In the small
coal these substances are generally detached from one another; .or form a
simple mechanical mixture, owing to the fact of the fracture or separation
generally following the plane of the junction of the different substances. The
separation of the coal from these different substances may be effected by care-
fully picking them out by hand, but the difficulty and expence of applying
such a process to the finer portion of the small coal completely debars its
adoption. This operation, which is almost impossible to be effected by the
skill of the hand and the discernment of the eye, is easily performed, in a very

page_text: perfect and economical manner, by mechanical means adopted for taking
advantage of the difference in the specific gravity of the different substances.
To obtain this result with the requisite precision, it is first necessary to
classify the whole mixture according to the size of the particles, which is
effected by an apparatus herein-after described.
Sheet 1 of the Drawings hereunto annexed represents a plan of the apparatus.
Sheet 2 represents a vertical transverse section at the line X, Y, in Sheet 1,
passing through the centre of the vessel No. 2. Similar letters refer to
similar parts in both Drawings. The coal as it comes from the mine is
deposited on the ground or on a floor, on a level with the classifying appa-
ratus, or thrown into an elevated hopper or reservoir, at the bottom of which
may be placed a distributor, which may consist of a revolving drum with
hollow cavities in its circumference, or it may be thrown upon a coarse grating
of bars, which separates the large lumps. The small coal falls into a trough
or ditch A of the form of an inverted pyramid. This trough or reservoir
should be large enough to contain a larger quantity of coal than is required
to supply the machine during the intervals of the arrival of tlie coal. One
side of this trough or reservoir is provided with an opening and a sliding door
or sluice B, B, through which the coal escapes into the space E, where it
forms a slope of an angle of about forty-five degrees. The coal is raised from
the space C by the buckets of an elevator or Jacob's ladder. The sluice B
serves to regulate the supply of coal. The elevator shewn in the Drawings
is formed of an endless chain of buckets, but an Archimedes' screw or any
other suitable elevator may be employed. Its purpose is to raise the coal and
deliver it upon the classifying apparatus. The elevator receives its motion
from the main shaft of a steam engine or other prime mover by means of
the pullies D, D, D', D'. These are live and dead pullies, for the purpose of
readily stopping and starting the apparatus. A pinion on the axis of the
pullies drives a toothed wheel on the axis of the lower wheel or roller 11.
A stretching apparatus E serves for tightening the endless chain of the elevator.
This is effected by making the bearings of the upper wheel or roller 10
capable of moving in slots or guides and attaching a screw E to each bearing.
This screw passes through a hole in the end of the guide, where it is secured
by two nuts. By turning these nuts the wheel or roller 10 is raised and the
endless chain is tightened. The whole apparatus is supported in a very simple
manner by two pieces of timber placed at the most convenient 'inclination, and
supported at top on a cast-iron cross beam. The general form of the appa-
ratus and the 'construction of the classifying apparatus is similar to that
described and shewn in the Specification of my former Fatent herein-before

page_text: mentioned. The differences will be seen by comparing that Specification with
the present one.
The classifying apparatus receives the coal from the elevator upon an
unperforated plate at its upper end. This classifying apparatus or classifier is
supported by two pairs of toothed segments gearing into racks fixed to its
sides, or by means of jointed rods 12, 12, which permit it to play backwards
and forwards with great freedom. A rapid to and fro motion is communicated
to it by means of a connecting rod jointed to a crank 13. The crank is
driven by bevil gearing 14, 15, the bearings of which are firmly fixed on a
foundation plate 16, supported by a strong wall 17. The classifier is inclined
from the commencement to the opposite extremity, and this inclination may
be varied at pleasure within certain limits by raising or lowering the cross
beams which support it. The coal delivered by the elevator passes imme-
diately upon a series of perforated plates fixed between the sides of the
classifier and raised in stages one above another. The first F, F, placed at
the upper part receives the whole of the matters to be classified. This plate
is pierced with circular holes as close together as consistent with leaving the
plate of sufficient strength. The diameter of these holes should be such that
the fragments which cannot pass through them may be large enough to be
readily picked over by hand. These holes being large the matters which are
smaller than the holes pass through with rapidity, and consequently this plate
does not require to be of large size. The fragments which cannot pass through
the holes advance continually, owing to the agitation of the classifier and its
inclination, until they reach the extremity of the plate F', where they meet
with an inclined plane f, f, which throws them on one side. When these
large coals can be sold to advantage the impurities are picked out by hand
and the coals are delivered by the incline f, f, into a wagon to be conveyed
away. If, on the contrary, it is wished to convert this coal into coke, and if,
as is frequently the case, it contains schist and sulphuret of iron or pyrites
interspersed in the coal itself, it becomes advisable to break up these large
fragments and pass it again into the apparatus. For this purpose the plane
ff, is inclined in the direction shewn in the Drawing, and provided with a
spout or trough in the position shewn by the line 18 to convey the coal into
a crushing mill, which may consist of two crushing cylinders or rolls G, G¹,
turning towards one another, and placed at a distance apart proportioned
to the size to which it is wished to reduce the fragments. One or both of the
rolls is kept in its place by means of a weight or counterpoise which yields if a
large fragment of very hard stone enters between the rolls, and thus prevents
the machine from being injured or broken. These rolls are driven by the main

page_text: shaft of the machine by means of the pullies II, H. H', H', II", II", "", "",
one of the straps of which is crossed. The coal thus broken or crushed fails
into the trough of the elevator, and is again raised by it to be again classified
and subsequently purified. The fragments of coal which are too large to be
treated in the purifying apparatus herein-after described are thus disposed of.
The matters which pass through the first plate F, F, fall upon the plate I, I',
placed immediately below and parallel to the first and perforated with smaller
holes. It is convenient to make the diameter of these holes such that the
matters which remain after the removal of the large lumps may be divided
into as many equal parts as there are purifying chests, as herein-after described.
Thus if three purifying chests are employed the plate 1, I', ought to arrest
one third of the coal and other matters which fall upon it. These matters
advance along the plate to I, where an inclined plane similar to that marked
ff, conveys them away to deliver them into the purifying chest No. 1, hy
means of a trough or spout. Below the plate I, I', is a plate K, K', with
still finer perforations, which furnishes to the chest No. 2 its corresponding
portion of the classified matters. Lastly, the matters, including the dust,
which pass through the plate K, K', fall on the fixed or moveable plate
L, L', and serve to supply the chest No. 3. The number of these plates and
chests may be increased or diminished at pleasure, but it will be found that
three is a convenient number to employ when purified coals of a medium size
are required; but when only very small coal for the manufacture of coke is
required, it suffices to classify the coal in two sizes, or even to reduce it all by
crushing to one small size, which with the dust may all be treated in one
purifying chest, or in several similar chests. As above mentioned the dust
remains mixed with all the matters which have passed through the last
perforated plate and passes into the chest No. 3. If it be required to obtain
the dust separate it is effected by adding another plate with still finer per-
forations, through which the dust passes. If the coal is dry, and if the dust
is required in a dry state, it is sufficient to receive it on an unperforated
plate, which directs it into a proper receptacle. If, however, the coal is moist
or in a muddy state, the perforated plates become clogged, and in order to
obtain a good classification it is advisable to effect it under the action of
water, whether the dust is conveyed into the chest No 3 or collected sepa-
rately. For this purpose the water is raised by a pump into a reservoir M
placed above the classifier. A sluice or valve regulates the passage of the
water from this reservoir to a distributor which is placed above the first plate
F, F, and the bottom of which consists of a plate perforated with very fine
holes which distribute the water over the plate F, F, in the form of fine rain.

page_text: The coal arriving from the unperforated plate at the upper end of the classifier
upon the plate F, F, is immediately submitted to the action of this rain,
which rapidly carries of the fine and dusty particles into the bottom of the
classifier. This bottom plate, in lieu of being fixed to and forming part of
the classifier, is preferably made independent of it, and is fixed on cross
beams resting on the main beams of the machine. This arrangement
lightens the classifier and renders its construction casier, as well as
reducing the power required. to work it. The water poured on the matters
in this manner is. an effectual means of carrying off the dust and pre-
venting the choking up of the finely-perforated plates. Moreover, when
the bottom or, last unperforated plate of the classifier is fixed, the water
serves to carry away the. dust which falls upon it from the last perforated
plate K, K, without the necessity of agitating it mechanically. The different
classified portions of coal, with or without the dust, pass separately into the
chests by corresponding spouts or troughs, as already mentioned. It is in these
chests that the purifying operation proceeds. These chests consist of a large
cistern or tank N, N', N", N, of wood or. of cast iron plates bolted together,
or of other suitable materials. Two partitions 0, 0, 0, 0, divide the chest
into principal compartments, each of which forms a purifying chest.. As
already mentioned the number of these compartments may be increased or
diminished if desired, but it will be found that three is a convenient number.
These chests being all arranged in a similar manner, with the exception of
slight differences herein-after mentioned, it will be sufficient to describe the con-
struction of one of them. At the back of each of the partitions or hinder walls
N, 0, 0, 0, 0, N", is a cylindrical part communicating at bottom with the
interior of the chest, and in which a piston with or without valves is capable
of working. A frame P, P', of wrought iron, or better of. cast iron, is fixed at
a certain distance below the edge of the chest, and supported by a flange or
ledge fixed. round the inside of the chest. The front edge of the chest is
lower than the other parts. Between the frame and the flange is a thickness
of wood which can be varied at pleasure, and which serves to regulate the
height of the frame, and its inclination from P to P¹. Upon the frame is
fixed a metallic.cloth or sieve, or preferably a perforated plate of metal or of
gutta percha, if there is reason to apprehend that the metal may be attacked
by acid in the water, which is sometimes formed from the pyrites in the coal.
If this plate is. thin and weak. it is strengthened by fixing it. between two
coarse metallic.cloths, or wirework sieves, or it is.fixed to, the frame by means
of iron bars extending from the hinder part to the front of the chest, or it is
fixed under an additional frame so as to be between two frames. The diameter

page_text: of the holes in the perforated plates of each chest is less than the correspond-
ing size of the coal arriving from the classifier, so that the matters to be
purified cannot pass through them, although the holes are still sufliciently
large to give freedom to the passage of water through them. A sluice Q, Q',
is capable of intercepting the communication between the part P and the part
P¹, or of leaving a more or less narrow passage between its lower extremity
and the plate of the frame, in proportion as it is lowered or raised. At the
lower extremity of the frame at P is a slide R, R', which is capable of moving
in a vertical direction, and being raised more or less by means of two rods
which support its ends, so that this slide forms a dam or weir moveable in the
direction of its weight. The extremity P¹ of the frame does not reach to the
back of the chest, but a space is left there for the passage of the schist,
which passes over the slide R, R', and falls into the chamber S. This
chamber is closed at bottom, and the schist which accumulates there has no
other 'issue than the small channel s, s', which may be totally or partially
closed at its exterior extremity by a sliding door.
Every thing being thus arranged, and the sluice q', q', closed and resting on
the perforated plate of the frame, the chest is filled with water up to the level
of the front edge, and the coal arriving from the classifier accumulates upon
the perforated plate. An up and down movement is then given to the piston T
either by an excentric or a cranked shaft receiving its motion from the machine,
or by a cam or cams, or by a crank, the pin of which works in a slotted lever
19, as shewn in the Drawing, so as to communicate to it a differential recipro-
cating motion, so that the motion in one direction is more rapid than in the
other direction. In whatever mode the piston is driven, its effect is to press
upon the water in' U, and to force the water in Uto mount upwards, passing
through the perforated plate P, P. The coal and other matters lying upon
the plate will be raised by the impulse of the water, but as they consist of
substances of different specific gravities, the lightest will be raised the highest,
especially when all the fragments are of nearly equal volume. 'A's the piston
ascends on its return stroke, the water will descend into U', and the matters
which had previously been raised will subside, from being of 'greater specific
gravity than water, as well as from the descending current of water. The
substances of greatest specific gravity which had been raised the least will
descend the most rapidly. By continuing the up and down motion of the
piston, the matters resting on the perforated plate will find themselves arranged
in horizontal layers in the order of their density, the heaviest portions being at
the bottom, and the lighter portions at the top. The light portion is the coal
nearly or quite free froin foreign matters, while the heavy lower portion

page_text: consists of schist and pyrites, or other impurities, which are of greater specific
gravity than coal. At the same time as the classified matters arrive in the
chest, a stream of water falls from the upper channel V into the chest at the
same place as that at which the coal arrives. This water forms a current on
the surface which carries the purified coal from the upper layer over the front
edge of the chest, and delivers it upon the inclined table x, y. The rapidity of
the delivery of the coal depends upon the quantity of water supplied to the
surface, which is regulated by a sluice. When the piston is caused to descend
quicker than it ascends, as is effected by the differential motion herein-before
mentioned, it follows that the ascent of the matters is more rapid than their
descent. This is frequently very advantageous; for, when the piston ascends
with great rapidity it causes a rapid descent of the coal and other matters,
and sometimes sucks the finer particles into the holes in the perforated plate
so as to obstruct the passage of the water, while a portion of the dust is carried
through into the lower part of the chest. By reducing this sucking effect to
a very small amount by the differential motion, the obstruction of the perforated
plate is prevented, as the upward current is then stronger than the downward
one, and the dust is not then drawn through the bed of schist and other
impurities, which itself forms a sort of sieve, and produces a good effect.
In the chest No. 3; more particularly, it is advisable to aid still
further this differential motion, by introducing upon the piston a current
of water from the conduit V. The piston is then made with a valve
opening downwards, and this additional current of water passes through
it, and serves to increase the ascending current through the coal and
other matters at the expense of the descending current. The inclination
of the frame and perforated plate in the opposite direction to the current
on the surface renders the action of the machine more regular in all parts,
for the bed of coal and other matters is thickest at the part nearest to
the piston, and where its action is most strongly felt, while the bed is thinner
at the part farthest from the piston, where its action is less powerful. The
inclination of the plate also causes the schist and other impurities to pass con-
tinually towards the opposite side of the apparatus to that at which the
purified coal escapes, which arrangement is favorable to a perfect separation of
the different matters. This is especially advantageous in the purification
of the dust or smaller particles when it is impossible advantageously to give
a great thickness to the lower layer of schist and other impurities. The
coal in leaving the chest falls upon the inclined table a, y. This table is
formed of a frame covered with a metallic cloth or cloth of any other substance
sufficiently fine to prevent the passage of any considerable quantity of dust or

page_text: solid matters while admitting of the passage of the water.
The table is pro-
vided with a raised edge on all sides except the front, towards which it is
inclined. This inclination may be varied at pleasure by means of a system of
suspension, consisting of two stiff rods placed at the angles next to the chest,
and two chains fixed to the opposite angles. The suspension is out of the
vertical direction, so that the table rests by its own weight against two stops
fixed to the front of the chest. A shaft carrying a cam or cams pushes the
table by its end away from the chest, and as the cam leaves it it falls back by
its own weight against the chest, and is thus exposed to a succession of blows
or agitations. The effect of these blows is not only to cause the purified coal
to advance towards the front of the table, where it is delivered into wagons
placed to receive it, but also to greatly facilitate the passage of the water
through the cloth which would otherwise soon become clogged.. In this
manner the coal, even of the last purifying chest, is delivered in a compara-
tively dried state, in lieu of in the state of nearly liquid mud. The blows or
agitations have also the effect of separating the very fine and heavy particles
of impurities which may have escaped the action of the purifying chest and
been brought over by the current of water. These particles remain at the
upper part of the table or pass through the cloth with the muddy water.
The water which has served to carry over the purified coal is received below
the inclined table in a large gutter fixed to the chests and conducted into
large basins or ponds arranged in a circuitous form or labyrinth. The fine
particles carried off by the water are here deposited and the water is con-
ducted back to the apparatus to be raised again by the large pump into the
upper conduit V, so that the same water serves over and over again for
carrying over the purified coal. In this way a very small supply of water is
required for the working of the apparatus, as almost the only loss of water is
that resulting from the coal entering the apparatus dry and leaving it
wet. As already explained the purified coal is delivered by the machine itself
into the wagons. The schist and pyrites and other impurities which accu-
mulate upon the perforated plate are disposed of in the following manner :-
The sluice Q, Q', remains closed until a sufficiently thick layer of schist has
accumulated upon the plate, and this layer may be called the safety bed, and
should be thicker in the chest No. 1 than in No. 2, and thinnest in No. 3.
This safety bed prevents the escape of coal with the schist. The sluice Q. Q',
is then opened sufficiently to give a free passage to the largest fragments.
a short time the space between the sluice Q, Q', and the slide R, R', becomes
filled with the schist and other impurities, which rise to the top of the slide
R, R', which is suitably adjusted. The safety bed of schist rises above
In

page_text: the opening under the sluice Q, Q, and thus prevents the coal from getting
into the space between the sluice Q, Q', and the slide R, R. The action of
the piston, or of what may be termed the water-sifting operation, is felt on
both sides of the sluice Q, Q', and consequently au equilibrium will be
established between the heavy column of schist and impurities contained
between the sluice Q, Q', and slide R, R', and the lighter column of coal and
schist on the other side of the sluice Q, Q. The heavy column of schist
is a constant quantity dependent upon the height to which the slide R, R', is
adjusted, while the lighter column varies in its weight with the relative pro-
portions of schist and coal; consequently, when the schist begins to accumulate
the variable column of coal and schist becomes heavier, and causes a portion
of schist to escape over the slide R, R¹. If on the contrary the supply of
schist diminishes or stops, the escape of the schist over the slide R, R', also
diminishes or stops. The escape of the schist is thus continuous and propor-
tionate to its supply. The schist in passing over the slide R, R', falls into
the compartment S, the lower part of which is formed of two inclined planes
which meet at the entrance of the passages, s', so that the schist is thus
conducted to the opening for its exit. This opening is adjusted by a sluice so
as to leave as narrow an opening as possible. The schist carried on by
the current of water escapes and falls upon the inclined plane s", s¹¹, formed
of a plate perforated with fine holes, through which the water falls into a
gutter which conveys it to the settling ponds or basins. The schist thus
drained of its water falls into a wagon, by which it is conveyed away. The
delivery of the schist and impurities is thus effected like that of the purified
coal in a continuous manner, by the machine itself, without manual labour.
The large quantities of coal which pass through the machine give rise after a
time to a muddy or clayey deposit at the bottom of the chest. This deposit
is removed at long intervals by means of a door or doors in front of the chest.
The machinery and apparatus above described is adapted for general use in
purifying coal, but in some cases certain additions or modifications may be
adopted. Thus when it is required to purify the fine powder or dust sepa-
rately, it may be effected by means of an apparatus or labyrinth arranged as
herein-after described, în lieu of employing a purifying chest like those herein-
before described. If the powder proceeds from a classification effected without
the aid of water it is conveyed from the classifier into a cistern A, A¹,
Figures 1 and 2, Sheet 3, by means of a flexible tube of leather. A quantity
of water, regulated by a sluice or a large cock, is led into this cistern
from a conduit or pipe. Two sluices V, VI, are placed at the front of the
cistern to admit of the escape of the water at the lower part, but only one of

page_text: these sluices is opened at a time. The opening of the sluice is below the level
of the water in the cistern, which in flowing out forms a small whirlpool, which
has the effect of drawing down and immersing the coal dust, which has a ten-
dency to float on the surface until it is throughly wetted. It may sometimes
happen that small lumps or pellets of dust adhere together without being
completely wetted: These are broken by the impulse of the stream of water
against the inclined board or plate B, B', which throws the current against
the vertical partition C, C', of a labyrinth or a series of depositing channels.
Each of the sluices V, VI, corresponds to a labyrinth arranged so as to afford
a great length of channel in a small space. The form of its convolutions may
be varied, or it may consist of a straight channel, where a sufficiently long
space can be devoted to it. The section of the first compartment D is a little
less than that of the following one E, which again is rather less than
that of the others. Beyond the sections may be equal. The bottom
of the first compartment from D to E is higher than that of the following
compartments; thus, in the three first compartments, the sectional area
increases as the distance increases from the entering point of the water and
coal, and consequently the rapidity of the current will successively decrease.
At the extreme end of the labyrinth are grooves or flanges, in which small
bars are laid from time to time to serve as a dam, and raise the level of the
point of exit as the labyrinth becomes filled. The point of exit is somewhat
lower than the commencement of the labyrinth, so as to determine a flow of
water. The velocity of the current being most rapid in the first compartment,
the heaviest particles only will deposit there, while in the second compartment
there will form a deposit of the finer portions of schist mixed with a propor-
tion of coal, which increases while the proportion of schist decreases with the
distance from the commencement of the labyrinth, so that in the third and
following compartments the coal which deposits is pure or nearly so. As the
deposit increases and forms a bed at the bottom of the labyrinth, the move-
able bars above mentioned are inserted from time to time at the end of the
labyrinth, so as to preserve the regularity of the action. When the deposit
has increased, so as nearly to fill the first labyrinth, the sluice corresponding
to it is closed and the other sluice is opened. The second labyrinth is then
filled in a similar manner, while the first is being emptied. The waters of the
labyrinths are conveyed into the settling basins or ponds, and raised again by
a pump for repeated use.
The last-described mode of proceeding is applicable when the coal dust
or powder arrives at the apparatus in a dry state from 'the classifier. The
same mode of proceeding is applicable when the dust is the result of a
classification carried on with the assistance of water, except that there is then

page_text: no difficulty in wetting the dust, and the water, which carries it through the
classifier, passes with it directly from the fixed bottom plate of the classifier
into the cistern, from which it passes into the labyrinths. Besides many
other important differences between the apparatus first herein-before described
and that described in the Specification of the former Letters Patent herein-
before mentioned, the reversing of the inclination of the frame and perforated
plate of the water-sifting apparatus is particularly to be noticed, as it affords
the facility for obtaining a continuous delivery of the schist and other impuri-
ties, instead of retaining them in the apparatus during the whole operation.
However, with the former position of the perforated plate, it is possible to
effect the removal of the schist in the following manner, without stopping the
operation.
Figure 3, Sheet 3, is a purifying chest, with the perforated plate inclined
towards the front, as in the former construction. The diagonal partition G
reaches to the perforated plate II, and the schist falls below it into the
compartment A. Two valves B, B', are placed at the bottom of the chest
in the compartments A and A' respectively, and cover two apertures, of which
B in particular is so large as to give a free passage to the schist. These
valves are accurately fitted to their seats, so that when closed they completely
cut off the communication. The apertures communicate with a chamber C, C,
furnished with a door on the face D, D'. After a certain period of work a
quantity of schist will have collected in the compartment A of the chest.
To empty it out, the valve B is opened, when the water and schist fall into the
chamber C, C, and when it is supposed to be filled or nearly so, the valve is
closed, so as to shut off all communication between the chamber and the
chest. The door D, D', is then opened, and the schist falls into a wagon
placed to receive it. The whole operation is performed without stopping the
working of the machine. By adopting the arrangement of the chamber for
receiving the schist shewn in Sheet 2, a smaller chamber suffices, and the
exit valve or sluice is kept constantly open for the escape of the schist. With
some sorts of coal, naturally containing clay or schist, which crumbles in the
water, the compartment A' of the chest will become obstructed after a time
with a clayey carbonaceous deposit, which collects in considerable quantity if
the piston has not a differential motion. To remove this deposit, the valve B¹
is employed to put the compartment A' in communication with the cham-
ber C, C, so that the deposit may be removed from time to time in the same
manner as the schist is removed. In place of constructing a separate
chaniber C, C, for extracting these matters, a portion of the bottom of the
purifying chest may be divided from the rest by a false bottom and employed
as the emptying chamber..

page_text: The various arrangements herein-before described are adapted for econo-
mically working on a large scale, and obtaining great perfection in the separa-
tion of the coal from foreign matters; but in some cases it may be preferable
to use a cheaper form of apparatus, although one less perfect in its action,
and requiring more manual labor, as, for instance, in cases where only a small
quantity of coal is to be purified. An apparatus of this sort is shewn in
Sheet 3, Figures 4 and 5. Figure 4 is a longitudinal section, and Figure 5
is a plan. a, b, c, d, e, f, is a vessel of wood, or of any other suitable material, .
the bottom of which is of a trapezoidal form with a rectangular prolongation
on the side of the base. The bottom of the trapezoidal part a, b, c, f, is
formed of two inclined planes, divided by the line a', 6. The retangular por-
tion is lower than these inclined planes. A current of water enters the vessel
at the side a, b, at the upper part, or at the lower part through a perforated
plate. A sluice or cock regulates or stops the supply of water. The coal
previously classified or not classified, but freed from all pieces of greater bulk
than a large nut, is brought to the side of the vessel, and is thrown by a
workman into the vessel at the place at which the water enters, while another
workman constantly draws the matters against the current of water by means
of a rake or scraper. lle does the same from time to time in the compart-
ment a', b, c. f.
The stream of water carries off the coal, which is the lighter substance,
and which deposits in the long rectangular part of the vessel c, d, e, f, the
section of which being larger than the first part, occasions the current to
diminish in velocity. At the extremity d, e, is a fixed grate, which gives free
passage to the water, but retains the solid matters of larger size than the
openings of the grate, allowing of the escape of the fine particles. When the
vessel c, d, e, f, is nearly filled with the carbonaceous deposit, the operation is
stopped, and the matters are found to be arranged in the following order :-
In the space a, b, a', b', is the heaviest portion of schist, and some large frag-
ments of coal. In the space a', bc,f, is the lighter portion of the schist, with
a considerable quantity of coal. In the rectangular space c, d, e, f, is the
purified coal, which still, however, retains a portion of the finer and lighter
particles of schist, especially near the part c, f. The first deposit in a, b, a², b¹,
is thrown aside. The second deposit in a, b, c, f, is treated over again, or
employed for purposes which do not require a pure coal. The third portion
in c, d. e, f, is the purified coal. If desired, the portion in the vicinity of c, f,
may be removed, to be again purified. It is convenient to employ two of
these apparatus, in order that the supply of coal and water may be entering
one of them while the other is being emptied. When the supply of coal is

page_text: limited, the water which has been employed may be conveyed into large basins
or ponds, arranged in a labyrinth or otherwise, where the fine particles of coal
and other matters may deposit, and the water may be again raised for use by a
pump or otherwise. This would, however, add much to the expense of the
establishment, which would still be inferior to that first herein-before described.
This mode of separating coal from foreign matters may be called washing coal
by a running stream.
In the last-described mode of purifying coal by a stream of water, the ope-
ration of stirring the coal and other matters is performed by hand, but it may
be performed by machinery; and in Sheet 4. I have shewn a longitudinal
section of an apparatus adapted for that purpose, and provided with agitators
revolving on vertical axes. The compartment in which these agitators
revolve are made circular in lieu of being of a trapezoidal form, like those
marked a, b, b, a', and a¹ b', c; f, in Figure 5, Sheet 3.
-
In Sheet 4, A is the first compartment, which consists of a large circular tub
or tun, in the centre of which is fixed the hollow cast-iron column Z, supporting
the shaft m, which turns in a step at the bottom, and in a collar or bearing n
at the top of the column. C, C, is the agitator fixed to the shaft m, and
guided at bottom by a ring r fixed to the column, and fitted to another ring s
fixed to the agitator. The shaft m carries a wheel Y which is driven by a
pinion on the shaft U, which carries a bevil wheel V, which receives it
motion from a bevil pinion T on the shaft R. The shaft R is driven by
bottom D, D, of the tun A
a steam engine or any other motive power. The
is inclined towards a central aperture b, which opens into the conical chamber
E, openings being left in the base of the column Z for that purpose. The
bottom of the chamber E is closed by the valve e, which is moved by the
lever g. The second tun F, with its column Z, shaft m, agitator G, and conical
chamber H, is constructed in a similar manner to the first.tun, and its agitator
is driven by a wheel Y gearing. into. the pinion X. B is a hopper for the
introduction of the coal and other matters into the first tun A. a, a, is a
passage or pipe connecting the first tun A to the second tun F. c is the exit
passage from the second tun F, which may be regulated or closed by the
sluice d. A stream of water from a pump or other source is introduced into
the first tun A by means of a pipe at , which is not shewn in. the. Drawing.
The two tuns are first filled about three quarters full by means of the pump,
and the water is kept at or about the same level during the continuance of the
operation by regulating the sluice d at the outlet so as only to admit of the
escape of the water and coal at the same rate as they enter. The continuity
of the current of water assists, the agitators in keeping the matters in a state

page_text: of suspension, which enables them to separate very quickly in the order of
their different specific gravities. The coal is brought to the top of the first
tun either by means of an inclined plane, when the nature of the ground will
admit of it, or by means of an elevator formed of an endless chain of buckets,
such as that herein-before described, which raises the coal from a ditch
or cavity in the ground, and delivers it into a hopper placed above, the tun, or
any.
other convenient mode of raising it may be employed. If desired a
perforated plate may be placed between the hopper and the tun to arrest and
throw on one side any large fragments of coal. These fragments are then
conducted to a crushing mill, and returned into the ditch or trough to be
again raised and passed through the apparatus.
As the matters arrive in the
tun the motion of the agitator causes them to move in a spiral direction
towards the bottom of the vessel. The schist and sulphuret of iron, and other
matters heavier than coal, fall first to the bottom of the tun, which, being made
slightly concave, causes them to fall into the conical recipient E placed in the
centre. The extremity of this conical recipient is closed by the valve e, which
is opened from time to time to discharge the matters collected in it. This
operation can be performed without stopping the working of the apparatus.
The small quantity of water which passes out with these matters is separated
by allowing them to fall on an inclined perforated plate o, and is conveyed to a
settling basin or labyrinth, and again raised by the pump for repeated use.
The coal, in consequence of its greater lightness, remains a little longer in
suspension in the water, and this time is sufficient for it to be carried from the
first tun into the second by the force of the current passing through the lateral
opening a, a. The foreign matters which may have been carried through with
the coal are deposited in the second tun, and enter the conical chamber II,
while the coal and water pass through the outlet c, and striking against
the inclined board I, fall into the channel J, which is lowest at the end
nearest the tun F, at which end there is an aperture closed by a
slide p.
If the separation of the matters should not be complete on their
exit from the second tun, it is effected in the channel J by the simple action
of the stream of water, which carries with it the coal, leaving behind the
heavier matters, which are from time to time removed from the channel by
opening the slide p, which permits them to pass away. At the end of the
channel is a metallic plate K perforated with very fine holes and inclined at an
angle of about forty-five degrees to the horizontal line. The purified coal and
the water which has served to carry it forward fall upon this plate K, the holes
of which give passage to the water, which passes off by the gutter i, pipe q,
and channel N, to a settling basin or labyrinth, whence it is again raised for

page_text: use. The coal, on the other hand, slides down the plate le and falls into a
wagon placed to receive it. The operation is thus carried on continuously,
and a large quantity of coal can thus be purified in a given time. The
operation is effected by mechanical means, with little or no manual labor on
the part of the superintendent, and a very small supply of water is required,
because the same water is used over and over again. When the coal is not
required to be very pure, or when the coal which is operated upon contains
but little impurity, a single tun may suffice in lieu of two.
In other cases
three or even more tuns may be employed in communication with each
other, but I consider that two will generally be found preferable to any other
number.
Having now described the nature of the Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do not
confine myself to the precise details and materials herein-before described, so
long as the peculiar character of any part of the Invention be retained;
but what I claim is,-
Firstly, the improved apparatus for separating coal from foreign matters
herein-before described in reference to Sheets 1 and 2.
Secondly, the application of a stream of water in the apparatus for classify-
ing the coal, and the application of a fixed or stationary bottom plate to the
same apparatus, over which the dust is carried by the aforesaid stream of
water, as herein-before described.
Thirdly, the application in the water-sifting apparatus for purifying coal of
a perforated sheet of gutta percha supported by bars or by a frame or frames,
as herein-before described.
Fourthly, the mode of causing the schist and other impurities to leave the
water-shifting apparatus and enter a chamber, from which they issue in a
continuous manner, as herein-before described in reference to Sheets 1 and 2.
Fifthly, the mode of purifying the fine powder or dust of coal by means of
a labyrinth constructed and arranged as herein-before described in reference
to Figures 1 and 2, Sheet 3.
Sixthly, the mode or modes of separating coal from foreign matters by
means of a stream of water applied in the apparatus herein-before described
in reference to Sheet 4, and to Figures 4 and 5, Sheet 3.
In witness whereof, 1, the said Charles Cowper, have hereunto set my
hand and seal, this Eighth day of June. One thousand eight hundred
and fifty-two.
CHARLES (L.S.) COWPER.

page_text: AND BE IT REMEMBERED, that on the Eighth day of June, in the
year of our Lord 1852, the aforesaid Charles Cowper came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the Eighth day of June, in the year of our Lord One
thousand eight hundred and fifty-two.