AN IMPROVED Apparatus FOR WASHING AND SORTING COAL AND MINERALS
Year: 1873

page_text: LETTERS PATENT to Maximilien Evrard, of Rue St. Louis, No. 14,
at St. Etienne, Loire, Engineer, for the Invention of "AN IMPROVED
Apparatus FOR WASHING AND SORTING COAL AND MINERALS.”
PROVISIONAL SPECIFICATION left by the said Maximilien Evrard at
the Office of the Commissioners of Patents, with his Petition, on
the 28th May 1873.
I, MAXIMILIEN EVBARD, of Rue St. Louis, No. 14, at St. Etienne,
Loire, Engineer, do hereby declare the nature of the said Invention for
"AN IMPROVED APPARATUS FOR WASHING AND SORTING COAL AND MINERALS,"
to be as follows:-
The characteristic feature of this Invention is the removal from a
charge of coal after it has been emptied into a deep vessel, the bottom
of which is movable and perforated, of all the various components of the

page_text: same various in size as well as in quality, without any loss or waste what-
ever. To obtain this result I act first on the charge by an ascensional and
intermittent current, in order to drive all the fine particles to the top;
then I produce graduated fluctuations of the water, from the greatest
height that can be usefully employed down to the smallest, in order to
sort the qualities. I next allow the slimy portions to become deposited
during an interval of rest, which varies from 2 to 5 minutes, according
to the nature of the coal. Lastly, I raise the washing table up to the
orifice of the vessel in order to effect the selection and removal of each
quality.
The apparatus is composed of a washing vessel (say, about 5 feet in
diameter and 9 to 10 feet high), in which is a washing table carried on
the upper
end of a piston rod, the piston of which works in a hydraulic
cylinder. At the upper part of the vessel is a scraper for removing the
layers of material; this scraper is brought to the back by a counter-
weight, and in its movement it slides on pins, which oscillate vertically,
in order to lift it above the charge. Below the washing vessel is a sump
in which a purging pipe is fitted to remove the small stones which pass
through the perforations in the washing table; and in communication
with the lower end thereof is a concentric vessel in which steam (or
other gas) acts the part of a piston upon the water. Valves admit air
into the vacuum which is produced under the table during its rising,
and in the concentric vessel by condensation during the intervals of
rest. There is a water reservoir under pressure of steam from the
boiler. There is a box containing three slides corresponding with
three hydraulic cylinders, viz., one for lifting the charge, one for the
washing table, and one for actuating the scraper. There are two
steam slides, viz., one for the piston action, and one for the reservoir
under pressure.
There is another reservoir containing water always
pure, which is brought by a pipe common to the outlets of the several
hydraulic cylinders. Valves re-establish the water level automatically
in the washing vessel and in the reservoir under pressure after cach
washing. An indicator worked by a chain fixed to the bottom of the
washing table shews the position of the table. It is by the steam in
direct contact with the water of the concentric vessel that all the
effects of a piston action are obtained. There is formed in the first
instance a layer of hot water, which remaining always at the surface

page_text: agent for producing the piston action is not indispensable for obtaining
the results peculiar to my system of washing, but it is nevertheless of
great importance because of the simplicity with which it produces
effects as varied as can be desired for the washing and sorting of minerals
generally.
The operation of washing is conducted as follows:-1st, steam is
slowly admitted into the concentric vessel in order to raise the water
about a foot and a half above the table, so as to protect it against the
fall of the coal, and to receive the charge; 2nd, the coal is emptied
upon a grating at the top of the washing vessel, so that the charge may
become divided, and fall regularly; 3rd, steam is then introduced inter-
mittently, so as to produce the rise of the water in successive strokes,
the intensity of which should be measured by the thickness of the charge
and the size of the coal. The intensity of the admissions of steam is
then gradually diminished according as the water level rises. In the
first moments the water which to a slight extent covers the charge is
much charged with mud, which opposes the return of the water by
forming a compact layer; but in the course of the operation when the
water covers the layer to a height nearly equal to its own the mud
becomes held in suspension. The upper part of the charge, which then
contains only granular particles, allows the water to filter through, and
fluctuations of any desired degrees are obtained either by employing the
partial escape of steam, or by regulating the admission on the descending
movement of the water, which is produced naturally by expansion and by a
slight condensation. After the washing and the time necessary for the
deposit of the mud the table is raised by its hydraulic piston, and the
washed material is then removed in one or several layers. The removal
of the lumps (pierres) and of the layer which immediately covers them
can only be effected after several operations. The water which is
retained by the impermeability of the upper layer flows during the rising
of the table by a channel into a purifying vessel, in which it deposits the
last traces of mud, and thence into the feed trough which restores it to
the apparatus. This first operation generally suffices to obtain the
superior layers fit for coke and agglomerated fuel, and the inferior layers
for heating, but it is easy to carry the classification further, if desired,
by lowering the table slightly after having scraped off the layer of mud

page_text: and very fine particles, and submitting each to the piston action after its
removal. I can in short reserve during several washings the layers
whose grains are much of the same size, and submit each of the
qualities separately to a fresh washing, but this would only be useful
for ores.
It should be remarked that the charge is sustained for its whole
height on issuing from the washing vessel, and it presents the appear-
ance of an agglomerated mass. When the scraper pushes it into the
shoot it becomes divided into vertical bands or strips containing mud
and particles of all sizes, which become intimately mixed in the fall.
There is thus realised in the most simple manner one of the chief
conditions sought after in the manufacture of coke, and agglomerated
fuel coke especially, which is much more homogeneous when the slimy
portions are preserved.
The mud deposited in the purifying vessel, as before named, and the
quantity of which is very small, is received in wagons, in which a layer
of coal has previously been placed, and this is subsequently mixed with
washed coal of corresponding quality.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Maximilien Evrard in the Great Seal Patent Office 2
on the 13th November 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MAXIMILIEN
EVRARD, of Rue St. Louis, No. 14, at St. Etienne, Loire, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 2
Letters Patent, bearing date the Twenty-eighth day of May, in the year
of our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Maximilien Evrard, Her special licence that
I, the said Maximilien Evrard, my executors, administrators, and assigns, 3
or such others as I, the said Maximilien Evrard, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from

page_text: material; this scraper is brought to the back by a counterweight, and in
its movement it slides on pins, which oscillate vertically in order to lift
it above the charge. Below the washing vessel is a sump, in which a
purging pipe F is fitted to remove the small stones which pass through
the perforations in the washing table. Around the washing vessel and
in communication with the lower end thereof is a concentric vessel H, in
which steam (or other gas) acts the part of a piston upon the water.
Two valves G admit air into the vacuum which is produced under the
table during its rising, and in the concentric vessel by condensation
during the intervals of rest. There is a water reservoir L under pressure
of steam from the boiler. There is a box J containing three slides cor-
responding with three hydraulic cylinders, viz., one, M, for lifting the
charge, one for the washing table B, and one for actuating the scraper E.
There are two steam slides O, O, viz., one for the piston action, and one
for the reservoir under pressure. There is another reservoir R, containing
water always pure, which is brought by a pipe common to the outlets of
the several hydraulic cylinders. Two valves re-establish the water level
automatically in the washing vessel and in the reservoir under pressure
after each washing. An indicator P, worked by a chain fixed to the
bottom of the washing table, shews the position of the table.
It is by the steam in direct contact with the water of the concentric
vessel H that all the effects of a piston action are obtained. There is
formed in the first instance a layer of hot water, which, remaining
always at the surface, renders condensation almost nil. This employ-
ment of steam as a direct agent for producing the piston action is not
indispensable for obtaining the results peculiar to my system of washing,
but it is nevertheless of great importance, because of the simplicity with
which it produces effects as varied as can be desired for the washing and
sorting of minerals generally.
The operation of washing is conducted as follows:-1st, steam is
slowly admitted by the slide O, in order to raise the water about a foot
and a half above the table, so as to protect the latter against the fall of
the coal, and to receive the charge; 2nd, the coal is emptied upon a
grating at the top of the washing vessel, so that the charge may
become divided, and fall regularly; 3rd, steam is then introduced inter-
mittently, so as to produce the rise of the water in successive strokes,
the intensity of which should be measured by the thickness of the

page_text: charge and the size of the coal. The intensity of the admissions of
steam is then gradually diminished according as the water level rises.
In the first movements the water, which to a slight extent covers the
charge, is much charged with mud, which opposes the return of the
water by forming a compact layer; but in the course of the operation,
when the water covers the layer to a height nearly equal to its own, the
mud becomes held in suspension; the upper part of the charge, which
then contains only granular particles, allows the water to filter through,
and fluctuations of any desired degrees are obtained, either by employing
tho partial escape of steam, or by regulating the admission on the
descending movement of the water which is produced naturally by
expansion and by a slight condensation. After the washing, and the
timo necessary for the deposit of the mud, the table is raised by its
hydraulic piston C, and the washed material is then removed in one or
several layers. The removal of the lumps (pierres) and of the layer which
immediately covers them can only be effected after several operations.
The water which is retained by the impermeability of the upper layer
flows during the rising of the table by a channel into a purifying
vessel N, in which it deposits the last traces of mud, and thence into the
feed trough, which restores it to the apparatus. This first operation
generally suffices to obtain the superior layers fit for coke and agglo-
merated fuel, and the inferior layers for heating, but it is easy to carry
the classification further, if desired, by lowering the table slightly after
having scraped off the layer of mud and very fine particles, and sub-
mitting each to the piston action before its removal. I may reservo
during several washings the layers whose grains are much of the same
size, and submit each of the qualities separately to a fresh washing,
but this would probably only be useful for ores.
It should be remarked that the charge is sustained for its whole height
on issuing from the washing vessel A, and it presents the appearance of
an agglomerated mass. When the scraper pushes it into the shoots it
becomes divided into vertical bands or strips, containing mud and
particles of all sizes, which become intimately mixed in the fall. There
is thus realised in the most simple manner one of the chief conditions
sought after in the manufacturo of coke and agglomerated fuel, coko
especially which is much more homogeneous when the slimy portions are
preserved.

page_text: It will also be remarked that for coal the classification is effected at
once, both according to size and to purity, owing to the slight difference
of density which exists between the very pure coal and that not so
pure.
The quantity of steam necessary for a washing operation in an
apparatus of the size herein-before mentioned is about 15 cubic metres.
It is supplied by the pressure reservoir L, after the action of the three
hydraulic cylinders, which absorb 3 cubic metres of water, replaced by
15 metres of steam at about 2 lbs. pressure; a special supply permits
besides in case of need of taking steam directly from the boiler. The
three vessels are surrounded with planks in order to avoid condensation.
The vessels L and H are supplied up to the water level of their trough
during the time of rest for the deposit of the mud. The apparatus may
be of any size large enough to treat at once the whole charge of a wagon
of 6 tons, for example.
The mud deposited in the purifying vessel N, the quantity of which
is very small, is received in wagons in which a layer of coal has pre-
viously been placed, and this is subsequently mixed with coal of
corresponding quality. The sump receives only stones (pierres) without
any trace of coal. This is explained by the fact that the water does not
return below the washing table until after it has been finally cleansed in
the purifying vessel. When it fluctuates it descends it is true partly
below the table, but it should be remarked that the fluctuation takes
place here in the layer of stones, and that these only can be drawn off.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,―
1st. Constructing apparatus for washing and sorting coal and minerals,
substantially as herein-before described.
2nd. The employment in such apparatus of steam (or other gas) to
produce the fluctuating movements of the water by its direct action on
the surface thereof, as described.
3rd. The process of classification described, in which simple ascen-
sional, intermittent, or fluctuating movements of the water produce all
the desired effects, the charge and the receiver being of considerable
proportions.

page_text: 4th. Making the washing table movable to permit of the selection
and removal of all the classified minerals in successive layers, as
described.
In witness whereof, I, the said Maximilien Evrard, have hereunto
set my hand and seal, this Twenty-eighth day of October, One
thousand eight hundred and seventy-three.
Witness,
ALBERT CAHEN,
Civil Engineer,
of 32, Boulevard Magenta,
at Paris.
MAX. EVRARD. (L.S.)