Year: 1897

page_text: Date of Application, 1st Apr., 1897-Accepted, 15th May, 1897

page_text: and the washing table, with a return by that of the hoppers hereinafter described,.
where it is necessary to accelerate the carrying away of the products. (If it is
a question, for example, of washing coal this will be the external hopper. The
pump will then draw the water from the trunk M', Figure 2, of the coal-noria.)
If necessary there is interposed between the rasing of the noria and the water
pipe Ja decanting box I in order to avoid the retura int the washer of finer
substances which otherwise would be drawn up by the pump. A filter bed of coke
or shavings occupies the central part of this box.
In front of the pipe F, an annular and eccentric recess b is formed in the
trough B to facilitate the equal distribution of the water and of the blow of the
pump all over the periphery of the washing table.
The arrangement which has just been described is applicable for washing any
substances containing a sufficient number of heavy grains sufficiently large not to
pass downwards through the holes in the washing table.
The
When the substances are very fine, the apparatus is modified in the manner
shown in Figure 4. In this case a washing table of the same form but unperforated
must be employed because the holes would be too small and would be quickly
obstructed. The material employed must, in such case," be somewhat resilient,
(like bronze or steel). The blow of the pump is then replaced, by means for
producing vibrations of the washing table.. The vibratious may be produced
mechanically either by a periodical shock of 'hammers g raised by cams A situated
on the external face of the washing table or by any other suitable means.
trough B is dispensed with, and the tube F discharges directly into the mouth of
the hopper d which then receives together the raw material, the foroing water and
the water discharged by the pump. This water then drives the material down in
such a proportion as the mass advances but slowly from the bottom towards the
top of the washing tuble. In this case, the lateral surface of the table must be
more inclined according as the substances to be treated are fiuer. The speed of
rotation must at the same time be increased to increase the centrifugal force which
determines the downfall of the substances treated on the table.
In the two arrangements bereinbefore described, the dimensions of the pump H
may be varied according to the nature and the quantity of the substances to be
treated. They must be determined in such a way that the volume of water shall
be just sufficient for raising and carrying away the heavier substances in spite of
the combined action of centrifugal force and gravity which tend to press them
energetically against the washing table.
The inclination of the lateral surface of the washing table must in both of the
aforesaid arrangements be such that at a normal speed of rotation the free surface
of the liquid shall be nearly parallel to it in such a way that the median part of
this lateral surface bisects nearly at a right angle the lines of force (see Figure 5).
Secondly, of annular sliding valves O and P which are arranged to effect the
separation of the various classes of materials treated which are collected at a
suitable height above the wasbing table. For this object the last element of the
internal slope of these valves must have the same inclination as the lateral surface
of the washing table.
Thirdly, of a cylindrical shutter N which is provided for closing the passages
over, between and under the sliding valves O and P by being raised or lowered, if
such should become necessary (more particularly when a sudden alteration in the
composition of the raw material being treated takes place). The water and the
lighter materials then flow away by the pipes U, Figures 2 and 3, in order to pass
into the compartment M, whilst the heavier rest upon the table.
Fourthly, of an external tight casing, the cover of which carries several devices
for operating the sliding valves O and P and the shutter N aud supports the
hopper d in the centre of which the motor shaft revolves. This funnel or hopper
serves for introducing into the apparatus the water and the substances to be
treated.
Fifthly, of tight partitious, arranged to divide the annular space comprised

page_text: between the external casing and the upper edge of the washing table into as
many distinct compartments as there are classes of material to be obtained (three
for instance). These partitions are fixed by cross pieces or better still by ridges
made on them at the time of casting. The upper part of cach of these partitions
aesumes a cylindrical form and fits with a sufficient play against the interior of
the corresponding annular sliding valve which is terminated also by a cylindrical
surface. Each annular sliding valve may be displaced vertically, it being guided
on the external face of the corresponding partition; thus the annular sliding
valve may be raised or lowered sliding on the partition O' and the anuular
Bliding valve P may be raised or lowered sliding on the partition P'. The height
of each separating sliding valve may thus be regulated independently of one
another.
Sixthly, of hoppers or drains K, L, M, of any suitable forin, for conveying the
Borted materials to the gears intended for extracting them from the washing
apparatus.
In the accompanying drawings, hoppers of cylindro-conical form terminated by
inclined drains are shown.
The whole apparatus held by the external casing is carried by two lugs E,
Figure 3, cast on to it and lie against. I-irons.
1
Seventhly, of tight compartiments K, L, M arranged to form a continuation of
the drains K, L, M, and rising up to above the piezometric level of the water
which is contained in the apparatus. It is in one of these three compartments
or even in each of them according to requirements that the suction pipe of the
pump opens. In the interior of these compartments also are arranged the norias,
buckets or other lifting apparatus which raise away the classified materiale.
In the apparatus shown in the accompanying drawings arranged for washing
coal sized from 0 up to inch, the decanting box I opens on the lateral face of
the trunk M' where coal buckets are placed and water is drawn by the pump H
from the decanting box by the pipe J. The coal passes over the valve into
the compartment M and is raised by the chain bucket M. The slaty particles
of coal pass between the two valves and P into the compartment. L and are
raised by the chain buckets L'. Finally the "slates" pass under the valve P
into the hopper K and thence to the chain of bucketa K. The hopper K also
receives the mud arising from the cleaning out of the trough B by means of the
plug valve.
Eighthly, of the devices for operating the shutter N and the sliding valves O P
comprising:
a) Screws such as Q fixed on the valve P, the nuts of which screws are fixed
in the centre of pinions R which engage with a circular rack W. This
rack bears on the external face of the vertical part of the cover by means
of ball bearings which facilitate its displacement. It is manipulated by
a hand wheel not shown in the drawing;
b) Screws such as Q' fixed on the valve O manipulated as hereinbefore
mentioned by other pinions R' and another circular raok W, also provided
with ball bearings ;
c) Hand wheels for operating, by pinions or endless screws according to the
degree of precision required, racks W W' which ensure the independent
movement of the valves O and P, and the securing of them at a suitable
height;
d) Vertical rods t fixed to the shutter N passing through stuffing boxes in.
the upper part of the cover in order to be manipulated from the outside
either by means of any suitable mechanical arrangement or preferably by
water, steam, air or any other suitable fluid under pressure, the said fluid
being distributed by a pipe S between cylinders T where it acte on pistons
fixed at the upper end of the operating rods. The admission or escape
of the fluid may be effected by turning a single three-way tap m, Figure 1,
placed at any suitable point within reach..

page_text: Ninthly, of grated valves G and G' which are characterised by a large delivery.
They are composed of three parts, the admission ajutage or mouth piece, the
grated valve seat and the delivery ajutage or nozzle. The valve seat, which
may according to requirements he horizontal or inclined, is formed of a grating
of cast iron, bronze or other suitable metal perforated with rectangular openings,
the greatest dimension of which is according to the line of greatest slope, if the
seat is inclined. The closing of each row of openings is ensured by a strip e of
leather, indiarubber or other suitable Hexible and impervious material, tightened
and maintained at its upper part by a metallic strip fixed by two screw bolts k.
Each sheet is divided into as many tongues as there are rectangular openings in
the row which it covers.
Tenthly, of a platform p arranged at any height which may be found must
suitable for the looking out, driving and manipulating of the apparatus.
Finally, of the pump H described incidentally in the paragraph relating to the
washing table, that rests on the framework of the platform or on foundations by
means of two luga cast thereon.
The working of the apparatus is as follows:-
The centrifugal washing apparatuses hitherto employed for the treatment of coal
or ore, only employed centrifugal force as an agent to convey the material to be
treated parallel to a surface on which they rested.
The principle ou which the apparatus hereinbefore described is based is quite
different.
The rotation of the washing table and of the inass of water which it carries with
it creates a field of force in which the centrifugal force and gravity are combined
and in which consequently the lines of force m n are no longer vertical straight
lines (Figure 6) but divergent curves (Figure 5). The conical wall of the washing
table is just about normal to the curved lines of force and behaves, in the washing
apparatus herein before described, as shown in Figure 5, exactly like an ordinary
horizontal wasbing table in an ordinary piston washing apparatus in which the
lines of force are vertical (Figure 6).
The advantage resulting from this is :-
1. A much greater velocity of separation because this velocity of separation is
for a given size proportionate to the square root of the acceleration imparted to
the unit of mass, an acceleration considerably increased by centrifugal force.
2. The possibility of increasing with the speed of the engine the speed of
discharge of the mass or of diminishing it by diminishing the speed of the engine.
An approximately constant thickness may thus always be ensured to the beds of
various classes. of material to be obtained whatever may be the proportion of
sterile material contained in the raw material subjected to washing.
The following is the mode of operation:-
The coal or ore as well as the water intended to replace that which is carried
away by the wash products are inserted in the hoppor & which must be maintained
constantly full. When granular products are treated upon a perforated table, the
speed of rotation must be such that under the action of the pump (80-200 strokes
per minute according to the size of the grains) the mass only moves slowly from
the centre to the circumference in such a way as to undergo a great number of
strokes of the piston. When pulverulent products are treated upon a solid table,
the vibrations of the table must be 30-50 per second, and the speed of rotation
must be such that transport from the centre to the circumference is very slow.
At each stroke of the piston or at each vibration of the table, the grains are
projected normally to the lateral surface and fall back on this surface becoming
sorted little by little by the downfall in the body of water, under the influence
of the acceleration which is imparted to them as the result of gravity and centrifugal
force combined together. In a word all goes on in this washing apparatus the
same as if it were a question of an ordinary washing plant where gravity came to
be cousiderably increased. The washing bed will have on the external edge of the
table a thickness so much greater. as the space between the bottom of the hopper

page_text: (which is always full) and the bottom of the table itself is greater. The materials
perfectly sorted in layers according to density present themselves before the sli.ling
valves which effect the separation into three (or more) distinct layers.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to me -
by my foreign correspondents, I declare that what I claim is :-
1. In a centrifugal washing apparatus for washing granular and pulverulent
materials, the use of a truncated conical washing table, perforated or otherwise,.
having a rotary motion according to the inclination of its lateral surface so that
the material to be treated circulates slowly and in a thick layer from the centre to
the circumference and near the valves becomes classified in layers according to
specific gravity under the action of pistonage or vibrations, substantially as
hereinbefore described.
2. In a centrifugal washing apparatus of the kind described, the combination,
with the aforesaid washing table, of a trongh, two grated valves or plugs and a
pump, when pistonage is made use of under a perforate table, the trough being
connected or not with a discharge plug, and in the other cases of two valves and a
pump substantially as described.
3. In a centrifugal washing apparatus of the kind described, the separation of
the classified materials into layers on their arrival at the exterior of the aforesaid
washing table by means of annular sliding valves adjustable in height substantially
as described.
4. In a centrifugal washing apparatus of the kind described, the means for
manipulating the shutter N and the sliding valves taken as a whole with their
grouping, reciprocal relations and application to simultaneous or isolated operation,
substantially as described.
5. In a centrifugal washing apparatus of the kind described, the division of the
space ouniprised between the external edge of the rotary table and the external
casing into as many annular compartments as there are classes into which the
material is to be separated by partitions or by valves and partitions substantially
as described.
6. In washing apparatus of all kinds, the arrangement of the safety shutter N
with the assistance of which all the ordinary discharge orifices can be quickly
closed when by a sudden change in the treated matorial it becomes necessary,
substantially as described.
7. In a centrifugal washing apparatus of the kind described, the construction of
the grated valves herein before doseribed taken onch as a whole and in its connection
with the remainder of the apparatus.
8. In a centrifugal washing apparatus of the kind described, the interposition,
when necessary, of a filtering box between the place from whence the pump draws
the water and the pump itself, substantially as described.
9. The general construction and combination of parts taken as a whole, forming
the improved apparatus for washing coal, ores, and other granular or pulverulent
material substantially as bereinbefore describe and illustrated.
Dated M 1807
WM. P. THOMPSON & Co.,.
Agents.