IMPROVEMENTS. IN THE TREATMENT OF COAL, AND IN THE PURIFICATION, DESICCATION, AND AGGLOMERATION OF COAL, AND IN MACHINERY AND APPARATUS FOR SUCH PURPOSES
Year: 1855

page_text: application for Letter's Patent was not given within the time prescribed
by the Act:):
PROVISIONAL SPECIFICATION. left by Charles Cowper at the Office of
the Commissioners of Patents, with his Petition,. on the 31st December
1855. A communication..
I, CHARLES COWPER, of No. 20; Southampton Buildings, Chancery Lane,
in the County. of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for IMPROVEMENTS. IN THE TREATMENT OF COAL, AND IN THE
PURIFICATION, DESICCATION, AND AGGLOMERATION OF COAL, AND IN MACHINERY AND
APPARATUS FOR SUCH PURPOSES, to be as follows:-
The Invention relates to improvements in separating coal from pyrites,
schist, and other substances by the action of water, and in drying the coal and
converting it into artificial fuel, or agglomerating it with the assistance of heat,
and in apparatus for such purposes..
I construct apparatus on the same principle as that described in the
Specification of certain Letters Patent granted to me, and bearing date at
Westminster,. 'the Second day of November 1849, with various modifications
adapted for the treatment of different qualities and species of coal. In the
apparatus described in the aforesaid Letters Patent, the coal is separated or
classified by sieves or perforated plates: into several sizes, which are separately
purified in a water-sifting apparatus, consisting generally of a vessel or chest
filled with water, and having a perforated plate or shelf on which the coal is
placed while a rapid up and down current of water is driven through the plate

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by means of a piston working in a cylinder or case. The pyrites and schist,
being specifically heavier than the coal, pass under a partition and fall into the
lower part of the chest, while the coal passes over the partition and slides down
an inclined grating through which the water. drains. away from it. In lieu of
this arrangement I cause the coal to be carried by a current of water, or by
the action of the water-sifting apparatus, into another vessel or compartment
containing water, from which it is raised up an inclined plane by means of an
endless chain of paddles. The water thus drains out of the coal as it ascends,
and it is delivered into waggons or other receptacles at the top of the inclined
plane. The water which drains from it runs back into the vessel and passes
into an adjoining compartment, whence it overflows through a wide opening or
weir, so that the motion of the water is very slow, and very little coal or dust
is carried away by it. When the coal contains argillaceous matter it is washed
by a supply of water in the form of rain, which is allowed to fall upon it as it
is carried up by the endless chain or elevator. In some cases, as when the dust
of the coal is very impure, the coal is passed over a perforated plate or metallid
cloth to allow a portion of the dust to escape. When, on the contrary, the
dust is nearly pure (as frequently happens with coal of a friable nature) the
outlet or weir for the escape of the water is closed or suppressed, and the same
water is constantly used with the addition of a small quantity" to compensate
for that carried away by the wet coal. The coal is then completely submerged
as it travels over into the second vessel, until it, is raised by the endless chain
or elevator. When the water which passes; away from the apparatus is to be
used again, it' is clarified by causing it to. flow through, a vessel divided into a
'series of compartments, in which the dust and impurities are deposited. The
water flows over each partition in a thin. sheet; with a very moderate velocity.
When a certain quantity: has collected, the stream, is diverted into another
similar vessel; while the first is emptied through sluices or otherwise.
.
The water-sifting apparatus is made with a deep vessel or well beneath it
for the reception of the muddy deposits, which are evacuated from time to
time through a sluice at the lower part. This, well is prolonged under the
cylinder, for which it forms the foundation; and its side which is opposed to
the cylinder is inclined. The whole is fixed with frames firmly imbedded in
masonry: The crank shaft which drives the pistons is supported by frames
cast with or firmly secured to the cylinders and chests and to each other, so as
to render the whole apparatus as: firm and solid as possible to resist the vibra,
tion caused by the rapid movement of the pistons.; The pistons are solid, and
a supply of water is introduced into the apparatus, when required, by a double-
acting horizontal pump of variable stroke, and regulated by cocks or valves.

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In some cases it is required to break up the large fragments of coal before,
purifying them, which is effected in the following manner: The coal is con-
veyed on to a series of perforated plates or sieves placed in stages in a frame,
which is suspended and acted upon by a cam, so as to, produce a succession of
blows or shakes. The largest fragments fall upon a table,, where a workman
picks out the large stones or foreign matters; the remainder is thrown between
a pair of crushing rollers, by which, it is reduced,, to fragments which pass
(together with the coal which has passed through the first sieve and been
retained by the, second, sieve), through.a. second pair of rollers placed closer.
together than the first pair. The crushed coal is mixed with that which, has
passed through the second, sieve, and the whole is then conveyed to the
purifying apparatus above. mentioned. The crushing, rollers may be plain or
grooved in one or both directions. Each crushing roller may be driven by a
separate wheel and pinion, and one of them is made adjustable, and is pressed
towards the other by screws or springs, or otherwise. When, the coal is all,
reduced to a tolerably uniform degree of fineness, the purifying, operation may
be. performed in a single purifying or water-sifting vessel. A convenient
apparatus for this purpose is constructed with a steam engine, mounted on the
apparatus itself; and driving direct to the crank shaft, from which the various
motions are communicated to the elevators, pumps, sieves, and other parts of
the apparatus. The coal is thrown into a hopper, which conducts it into the
first of two sieves worked by a cam. The fragments which are stopped by the
first sieve fall upon a table or grating, where the large stones and foreign
matters are picked out by hand. The large lumps of coal may be placed aside
for separate use, or they may be broken up on the grating, through which the
fragments fall between two crushing rollers, which also receive the fragments
which have, passed, through the first sieve and been arrested, by the second
sieve. The coal crushed by the rollers is mixed with that, which has passed
the second sieve; and the whole is conveyed by an elevator to the water-sifting
apparatus connected with a vessel having an inclined plane and endless chain
of paddles, as before. The partition, between the two vessels being below the
surface of the water, the coal is gradually carried over the partition and
removed by the endless chain. The pyrites, and., schist are carried, by the
action of the piston; (assisted, if necessary, by inclining the perforated plate,)
in the opposite direction, and pass under one and then over another adjustable
partition or sluice, and fall into a receptacle, from the end of which they are
removed. A very small supply of water is required for this apparatus. In
some cases, however, as for instance, when the coal contains clay or argillaceous
matter, it is advantageous to renew the water more rapidly. In this case an

page_text: overflow aperture or weir is provided, and a supply of water is introduced by a
pump. The water which overflows is clarified by subsidence, and employed
again. The pump may be driven by a prolongation of the piston rod of the
steam engine. A smaller water-sifting apparatus, which may be worked either
by hand or by steam, is constructed with a moveable sieve or perforated plate,
which is fitted into one compartment of a vessel or chest, which is divided by a
partition. The sieve is worked up and down rapidly by means of a lever
worked by hand, or by a steam cylinder and piston, or otherwise. The pyrites
and schist collect upon the perforated plate, while the purified coal travels over
the partition into the second compartment, where it is received in a perforated
receptacle through which the water passes; and returns through a valve to the
lower part of the first compartment. The coal is removed by hand or by the
elevator, as before. This apparatus may also be constructed without the valve
and the perforated receptacle, the water being allowed to pass between the sieve
and the sides of the compartment in which it works. The coal on leaving these
apparatus retains about twelve per cent., more or less, of water, and for many
purposes it is desirable or necessary to obtain it in a dry state or nearly so.
About half this water may be removed by allowing it to drain for a day or two,
after which the loss of water is very slow. The cost of placing the coal in
heaps, and afterwards removing it by manual labour, would, however, be so
great as to materially enhance the cost of the coal. The drying is effected by
machinery in the following manner-The coal is carried up by the elevator
or endless chain of paddles, herein-before mentioned, and delivered on the
centre of a horizontal endless web, which is capable of travelling in either
direction. This web is placed above two large bins or chambers with inclined
sides into which it distributes the coal. The coal coming from the purifying
machine during one day's work is distributed in one bin, and the endless web
is reversed, so as to distribute the next day's work in the other bin. A con-
siderable portion of water drains away from the coal in these bins, which have
openings for its escape. The coal is then allowed to fall upon another endless
web placed below the bins, which conveys it to the foot of a long inclined
horizontal semi-cylindrical trough, in which works a long flat-threaded screw:
The coal is thus gradually carried up the trough and delivered at its upper end
into waggons or a receptacle provided for it: The trough has a double bottom
through which a current of hot gas or air is conveyed for the purpose of drying
the coal. A number of slits or perforations are made in the trough to allow
the hot air to pass through the coal. When a source of heat, such as a coke
oven, is near the apparatus, its heat may be applied for heating air for drying
the coal, or the products of combustion may be at once conducted into the

page_text: double bottom of the trough; or a fan driven by a steam engine is employed
to supply air to the fire of the steam boiler, and the products of combustion
are passed into the double bottom of the trough. When the temperature of
the products of combustion is injuriously high, a portion of cold air from the
fan is mixed with them. A flue is also provided for conveying the products of
combustion direct to the trough, in lieu of passing under the boiler. All the
flues or passages are provided with suitable valves or registers, so that the pro-
duction of steam in the boiler and the temperature of the air passing up the
trough are completely under control. The coal thus dried, and, while still
warm, may be at once agglomerated or converted into artificial fuel. For this
purpose it is allowed to fall into a hopper, where it meets with thin streams of
cold or hot tar, and the mixture passes down an inclined or vertical cylindrical
pipe or retort containing a revolving screw or spiral; or a retort is used of a form
similar to that of several pipes placed side by side and communicating together,
and having a screw in the axis of each pipe. The materials are thus prevented.
from adhering to the sides of the retort, which is heated by a fire. The pasty
mixture issues from the lower end of the retort and passes between grooved or
plain rollers, by which it is compressed and driven through a spout or die on
to a table or series of rollers, where it is cut into convenient lengths. Spring
blades press against the surface of the rollers to prevent the escape of the
material; or the rollers are made with deep grooves, of the form of the prisms
or blocks of fuel to be produced, and they are made to dip into water, or water
is passed through them to cool them and prevent the adhesion of the materials.
The blocks of fuel may be allowed to fall into water, or they may fall upon an
endless web which conveys them away. The ends of the blocks or prisms may
be compressed by mandrils or plungers entering the grooves of the rollers.
After this compression one mandril retires and the other continues to advance
a little, so as to detach the block from the rollers.
By this Invention inferior descriptions of coal containing large quantities of
pyrites and other impurities may be classified, purified, dried, and converted
into an artificial fuel of great purity, and at a comparatively trifling expense, as
the various processes are performed by the machinery herein-before described,
with very little manual labour.