IMPROVEMENTS IN WASHING COAL AND MINERALS, AND IN APPARATUS EMPLOYED THEREIN
Year: 1872

page_text: LETTERS PATENT to Maximilien Evrard, of Sorbiers, near St. Etienne,
Loire (France), Civil Engineer, for the Invention of "IMPROVEMENTS
IN WASHING COAL AND MINERALS, AND IN APPARATUS EMPLOYED THEREIN.”
Sealed the 4th February 1873, and dated the 13th September 1872.
PROVISIONAL SPECIFICATION left by the said Maximilien Evrard at
the Office of the Commissioners of Patents, with his Petition, on
the 13th September 1872.
I, MAXIMILIEN EVRARD, of Sorbiers, near St. Etienne, Loire (France),
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN WASHING COAL AND MINERALS, AND IN APPARATUS EMPLOYED
THEREIN," to be as follows :—
By means of my Invention I effect perfect cleansing and classification
of the coal or mineral.
The Invention consists in charging the washing table with a very
thick layer of coal, and in acting first on this layer by a stream of
water, ascensional only, in order to drive the fine particles into the upper
layers; then in effecting the classification by order of density by a

page_text: reciprocating movement given to the water and progressively varying its
effects by means of the direct action of steam or compressed air on the
surface of the water.
I proceed to describe an apparatus which I have designed for carry-
ing out my Invention; it is composed of a cylindrical or other vessel,
which receives the charge of coal on a washing table provided with
a screen or sifter. The table is a sort of piston suitably packed and
capable of sliding the whole height of the vessel; it carries for this
purpose a rod which is terminated by a lower piston. This latter works
in a cylinder fed with water pressed by steam. The table can therefore
rise, descend, or remain motionless. A sump collects the mud and
stones which pass through the screen. This sump has a syphon
cleansing pipe, in which a rod terminated by a wire rope which enters
the sump serves to loosen the material in case the pipe gets clogged.
There is a receiver surrounded with wood to prevent loss of heat; it
contains steam at its upper part and cold water at its lower part, while
the intermediate portion contains hot water arising from the conden-
sation of the steam. A float composed of a floor of several stages
retains the boiling water at the surface during the oscillations or
fluctuations of the whole column of water. A slide box distributes the
steam to regulate the movement of the column of water at each of
the pulsations. A pipe furnished with a cock introduces air into the
vacuum or space produced under the table when the filtration of the
water is interrupted. Tubes indicate the water level in the vessel and
the receiver. There is a reservoir in communication with a steam
generator to feed the water cylinder with. the same water, allowing to
escape after each stroke the volume of steam.
A scraper worked by a
winch or by steam power removes the materials. Each quality of coal
is discharged into a corresponding shoot.
:-
The working of the apparatus, which will vary according to the
quality or description of material under treatment, is substantially as
follows I place on the washing table, when the material to be washed
is slimy, a screen or sifter of large meshes, which is suspended at the
end of a balanced beam; this screen raises the partial or entire charge
when the latter begins to be held in. suspension by the ascensional
stream, and it gives passage to the fine particles (grains fins) and slimy
portions (moures). The screen may be raised or lowered by means of a
winch or otherwise. If the washing table is at its highest position I

page_text: lower it about 18 inches in the water, in order to throw therein a first
layer of about 7 inches, and I continue its descent. with a speed
sufficient for the ascensional stream of water which is produced through
the screen to separate the fine particles and deposit the other portions
(grains) on the screen. This first layer is intended, first, to facilitate the
regular admission of the ascensional stream and prevent afterwards the
drawing into the vessel of the finest particles. The lowering of the table
is continued in proportion to the charging of the material until the
desired charge is made, say, from 1 to 3 feet. The charge being
complete, the waste or slimy part becomes deposited, and as by its im-..
permeability it would offer opposition to. the return of the water, and
therefore to a new action of the ascensional stream, I cause this slimy
part to flow through the mass by filtration. For this purpose, firstly,
I introduce in the charge at the end of the charging a screen of close
meshes at the depth indicated by the more or less slimy nature of the
coals in the layer of fine particles, and I create by raising it slowly
renewals of surface, interstices between the particles by which the water.
finds passages always changing, in which the slimy portions deposit;
and, secondly, at the moment the charge is finished the level of the
water being returned below the washing table by the escape of the
steam there is produced under the table a space or vacuum, into which
I introduce a volume of air by the air pipe; this volume of air, after-
wards discharged by a new elevation of the water to the washing table,
traverses the whole charge and produces agitation of the material and
interstices favorable to the filtration. After a few of these liftings by
the air and fluctuations of the water. produced by the admission and
escape of the steam, the particles of stone (grains de pierre) contained
in the slimy portion descend into the lower layers below the latter, and,
the removal of the slimy portion should then be effected in order that
the cleansing of other portions or charges may be continued more easily.
Consequently the washing table is lifted until the first charge is level
with the orifice of the tube or vessel in order that it may be discharged
therefrom. From this time the classification of the mass continues
without inconvenience, since the impermeable layer is removed by the
varied action of the water on each of the portions or charges by means of
the admission and escape of the steam into the receiver in such manner
as to bring the densest grains or particles into the lower layers. In
proportion to the progress of the classification the table is raised again
and the charges or portions are removed in order to avoid the pressure

page_text: on the others.
The quality immediately superposed on the stones
(pierres) and the stones themselves can only be removed after several
operations; this is necessary in treating charges of very different sizes
in order to establish best the lines of demarkation between the layers
of large pieces which occupy the lower parts.
For coals which are not slimy, and for other qualities, such as small
coal or slack (menus), the size of which requires a more active working
of the piston, and which cause no obstacle to the return of the water
into the vessel, the operation can be conducted by commencing at the
bottom position of the table; in this case it suffices to produce the
ascensional stream by the raising of the water.
The supply of the vessel takes place when the water level is at its
lowest by a channel opening into a reservoir at a higher level; this
reservoir also receives the water which is emptied from the tube after its
clarification in the settling basins.
.
The division in water of the slimy and pasty coal being one of the
essential conditions of the washing, I sometimes submit it to a pre-
paratory process previous to that on the screens, either by depositing it.
in one or more openwork metal baskets, which are agitated in the
vessel, or by other apparatus of any ordinary construction, before charging
it on the washing table. I also employ steam dabbling in a receiver
with or without agitators, and even in the washing vessel, the washing
with boiling water facilitating the disaggregation of the lumps, and
injections of steam replacing compressed air to obtain a first classing of
the heaviest pieces.
To extract the coal from the preparatory washing vessels, or from the
other washing vessel, when they are classified, without lifting the table,
I employ as required an extracting apparatus composed of a sheet metal
vessel, the bottom of which is formed of narrow flat bars sufficiently.
separated to give passage to the pieces of coal in its downward move-
ment, but sufficiently close to hold the charge when left to itself.
This extractor can effect the removal of each of the charges or layers
as they are cleansed, even that of the stones, but I prefer to effect it by
the lifting of the table.
'

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Maximilien Evrard in the Great Seal Patent
Office on the 20th February 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MAXIMILIEN
EVRARD, of Sorbiers, near St. Etienne, Loire (France), Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of September, in the
year of our Lord One thousand cight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and suc-.
cessors, give and grant unto me, the said Maximilien Evrard, Her
special licence that I, the said Maximilien Evrard, my executors,
administrators, and assigns, or such others as I, the said Maximilien
Evrard, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN WASHING COAL AND MINERALS, AND IN APPARATUS
EMPLOYED THEREIN," upon the condition (amongst others) that I, the said
Maximilien Evrard, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and scals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Maximilien Evrard, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Drawings, that is to say:
By means of my Invention I effect perfect cleansing and classification
of the coal or mineral.
The Invention consists in charging the washing table with a very
thick layer of the coal, and in acting first on this layer by an ascensional
stream of water in order to drive the fine particles into the upper
;

page_text: layers; then in effecting the classification by order of density by a
reciprocating movement given to the water, and progressively varying its
effects by means of the direct action of steam or compressed air on the
surface of the water.
Figures 1, 2, and 3 of the Drawings represent three views of the
apparatus which I have designed for carrying out my. Invention.
A is a cylindrical or other vessel, which receives the charge of coal
on a washing table B. The table is hermetically packed, it can remain
motionless or rise and descend the whole height of the vessel; it carries
for this purpose a rod C, which is terminated by a lower piston e. This
latter works in a cylinder D, fed with water pressed by steam. A sump
E collects the mud and stones which pass through the screen b. F is
a cleansing pipe which dips into the bottom of the sump E. A receiver
G, surrounded with wood to prevent loss of heat, contains steam at its.
upper part and cold water at its lower part, while the intermediate
portion contains hot water arising from the condensation of the steam.
A float R composed of a floor of several stages retains the boiling water
at the surface during the oscillations or fluctuations of the whole
column of water. A slide box H distributes the steam to regulate the
movement of the column of water at each of the pulsations. A pipe T,
furnished with a cock, introduces air into the vacuum or space produced
under the table when the filtration of the water is interrupted. Tubes
I and J indicate the water level in the vessel and the receiver.
reservoir K is in communication with a steam generator K³ to feed the
cylinders D, D', D", with the same water, allowing to escape after each
operation the volume of steam. The cocks of these cylinders have
always three ways, and allow of several courses being furnished without
making the steam escape from the reservoir K; it is therefore only
necessary to replace after each operation the water lost in this reservoir.
A scraper M sliding in guides and worked by a winch or by steam
power or hydraulic power D' removes the materials. Each quality of
coal is discharged into a corresponding shoot N, O, P.
A
The working of the apparatus, which will vary according to the
quality or description of material under treatment, is substantially as
follows:-
1st. I empty into the vessel through a grating in order to disaggre-
gate the lumps all the desired charge, taking care to maintain the water

page_text: do not pass through.
2nd. The charge having been made I raise the water level (by an
admission of steam into the receiver G) in order to bring the dust and
dirt to the top of the charge, then I allow the steam to escape from the
receiver. If the dust and dirt form an impermeable layer, as is often
the case, the water cannot return into the receiver G because it is
retained by the vacuum, I therefore open the cock of the pipe T, and
the air then occupies under the washing table all the space left free by
the displacement of this volume of water which is now above the charge.
By a fresh admission of steam into the receiver G the air is forcibly
driven through the charge, and produces a dabbling or working up,
which. is often necessary in order to mix water with the materials. The
water which immediately succeeds the air through the washing table
therefore rises in the vessel, and I can obtain by its varied effects (either
by an intermittent ascensional current, or by oscillations or. fluctuations
of different amplitudes) all the desired results. After a few of these
liftings or workings up by the air and varied fluctuations of the water
produced by the admission and escape of the steam, the particles of
stone (grains de pierre) contained in the slimy portion (moures) descend
into the lower layers below the latter, and the removal of the slimy
portion should then be effected in order that the cleansing of other
portions may be continued more easily. Consequently the washing
table is lifted until the first portion is level with the orifice of the tube
or vessel, in order that it may be discharged therefrom. From this time
the classification of the mass continues without inconvenience (since the
impermeable layer is removed) by the varied action of the water on each
of the portions or charges by means of the admission and escape of the
steam into the receiver G in such manner as to bring the densest grains
or particles into the lower layers. In proportion to the progress of the
classification the table is raised again, and the charges or portions are
removed in order to avoid the pressure on the others. The quality
immediately superposed on the stones (pierres), and the stones them-
selves can only be removed after several operations; this is necessary in
treating charges of very different sizes in order to establish best the lines
of demarkation between the layers of large pieces which occupy the
lower parts.

page_text: The supply of water to the vessel takes place when the water level
is at its lowest by a channel opening into a reservoir at a higher level;
this reservoir also receives the water which is emptied from the tube
after its clarification in the settling basins.
The division in water of the slimy coal and muddy mineral being 5
one of the essential conditions of the washing, I effect this division by
dabbling or working up with steam in a receiver (with or without
agitators), or in the washing vessel itself by employing then boiling
water in order to facilitate the disaggregation of the lumps. Injections
of steam will then replace compressed air in order to produce the 1
dabbling or working up and to obtain a first classing of the heaviest
pieces.
To extract the coal from the preparatory washing vessels or from the
washing vessel A when they are classified, without lifting the table,
I employ as required an extracting apparatus composed of a sheet 1
metal vessel, the bottom of which is formed of narrow flat bars suffi-
ciently separated to give passage to the pieces of coal in its downward
movement, but sufficiently close to hold the charge when left to
itself. This extractor can effect the removal of each of the charges
or layers as they are cleansed, even of the stones (pierres) but I prefer 2
to effect it by the lifting of the table.
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 as my
"Improvements in Washing Coal and Minerals, and in Apparatus
employed therein, "—
First. Washing coal or minerals substantially in the manner and by
apparatus arranged and acting as herein-before described.
Second. The employment of steam or other gas to produce the piston
action at any height with considerable charges and heights of water as
herein-before described.
'
Third. The removal and purging of the slimy portion by the ascension
of water through charges of any thickness as herein-before described.
Fourth. The treatment of minerals in thick charges in order to
effect the classification in thick layers instead of in thin layers as
herein-before described.
2
30
30

page_text: Fifth. The capability of movement of the washing table by means
of the hydraulic lifter worked by steam pressure, or of other mechanism
as herein-before described.
Sixth. The employment of compressed air and of steam for working
up the particles and facilitating their classification, or for effecting the
filtration as herein-before described.
Seventh. The mixing of the coal or mineral with and washing by
boiling water as herein-before described.
Eighth. The sliding scraper for removing the layers of materials as
hercin-before described.
Ninth. The screens, extractor, and cleansing pipe, all as herein-before
described.
In witness whereof, I, the said Maximilien Evrard, have hercunto
set my hand and seal, this Fifteenth day of January, One
thousand eight hundred and seventy-three.
MAXIMILIEN EVRARD. (L.S.)
Witness,
ALBERT CAHEN,
Civil Engineer,
No. 32, Boulevard Magenta, at Paris.