NEW OR IMPROVED APPARATUS FOR WASHING AURIFEROUS SANDS AND OTHER MATERIALS SUSCEPTIBLE OF SEPARATION BY WASHING
Year: 1877

page_text: LETTERS PATENT to Ernest Bazin, Civil Engineer, of Paris, in the Republic of
France, for the Invention of "NEW OR IMPROVED APPARATUS FOR WASHING
AURIFEROUS SANDS AND OTHER MATERIALS SUSCEPTIBLE OF SEPARATION BY
WASHING
"
Sealed the 13th October 1877, and dated the 16th April 1877.
PROVISIONAL SPECIFICATION left by the said Ernest Bazin at the Office
of the Commissioners of Patents on the 16th April 1877.
ERNEST BAZIN, Civil Engineer, of Paris, in the Republic of France. "NEW OR
IMPROVED APPARATUS FOR WASHING AURIFEROUS SANDS AND OTHER MATERIALS
SUSCEPTIBLE OF SEPARATION BY WASHING."
The present Invention has for object the washing of auriferous sands and other
matters by means of more or less hollow rotating pans wholly immersed, which offer
by reason of their form, inclined planes which oppose resistance to the heavier matters
and allow of the expulsion of the lighter matters, this expulsion taking place in pro-
portion to the centrifugal force. This means of effecting the washing, that is to say,
the separation of matters of different densities under water by centrifugal force by
means of circular, rotating, and more or less hollow pans with inclined sides, pro-
duces real and completely novel advantages which characterize the combination of
my washing apparatus.
When operating upon, say auriferous sands, their deposit upon the bottom of the
immersed pan immediately causes the sands to loose fifty per cent. at least of their
weight, whilst the gold only loses a tenth part of its weight. Under these conditions it
will be understood that the separation of the light or sterile matters from the heavy
or rich is greatly facilitated. This separation is obtained by imparting to the pan
a rotary movement which in proportion to the centrifugal force determines a re-
pulsive action of the materials from the centre towards the circumference of the
washing plate.
The water which causes the sands to lose half their weight also plays the im-
portant part of divider. In fact the mass of water which covers the pan only
receives insensibly and to an infinitisimal extent the rotary motion imparted to the
thin separator plate and to the materials it contains; it thus offers a certain amount
of resistance to the said materials and divides them.

page_text: Finally, after having served as dividing agent, this same water overpowers and
regulates the energy of the repulsion produced upon the materials by the centrifugal
force, that is to say, by its relative inertia (since it does not partake of the centri-
fugal action any more than it partakes of the rotary motion) it becomes a resistance
and destroys a part of the centrifugal effect imparted to the heavy materials whilst
it allows of the expulsion of the light materials.
A washer such as that of which I have above explained the principle, that is to
say, an apparatus composed of a circular pan (or washer plate carrying circular
inclined planes) rotating in and completely immersed under water, expelling the
material by centrifugal force offers the following advantages:—
1st. Causing the materials which are to be expelled to lose a considerable part of
their weight by their complete immersion.
2nd. Obtaining the division of the materials previously to the action of expulsion
by virtue of the resistance furnished by the water, which is not drawn round by the
rotary motion imparted to the separator plate.
3rd. Preponderance over or regulation of the effects of rejection or repulsion which,
although necessary for the expulsion of the lighter sterile or useless materials, are by
reason of the inertia of the water almost nullified in those materials which aro
heavier volume for volume.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernest Bazin in the Great Seal Patent Office on the 15th October
1877.
ERNEST BAZIN, Civil Engineer, of Paris, in the Republic of France. "NEW OR
IMPROVED APPARATUS FOR WASHING AURIFEROUS SANDS AND OTHER MATERIALS
SUSCEPTIBLE OF SEPARATION BY WASHING."
The present Invention has for object to secure the separation of matters of
different densities by the help of an immersed circular rotative washer designed to
effect undor water the expulsion of the barren matters by centrifugal force. The
form of washer which I consider the most practical and the most suitable is
that of a spherical cap forming pans (or basins) which are moro or less hollow, and
receive a movement of rotation variable, according to requirement, which will be
imparted by hand in washers of small dimensions, and by machinery when the
dimensions are considerable.
This washing apparatus may equally be composed in certain cases of circular
plates, flat, convex, or concave, of pans (or basins) more or less hollow, even with
vertical sides (or rims). These washers of different forms may be covered withi
woollen material, cloth, or india-rubber, placed circularly in strips in order to oppose
the escapo of rich but thin or fine matters, such as for example gold scales or flakes
(paillettes d'or) and dust.
The pans (or basins) may contain a bath of mercury suitable for facilitating the
operation of amalgamation.
Finally, the apparatus may evidently be varied in form and be applied in many
ways, but it will always consist of an immersed circular rotative washer driving out
the barren matters under water or other liquid by centrifugal force.
I apply my washer especially to gold, that is to say, to the washing of quartz
sands and auriferous alluvions, but it must be understood that I reserve to myself
the application for all matters susceptible of being separated by the action of
washing.
DESCRIPTION.
The Drawings hereto annexed shew in Figure 1 the detail of construction and
mounting of a washer of the formn of enharinal can the dotted lines sonucantium ma

page_text: Figure 3 is an illustrative view similar to Figure 1, but with a pan more or less
deep and having a larger base; Figure 4 shews a vertical section of this washer
complete.
Figure 5 represents a vertical soction of a complete washer with a spherical cap-
shaped pan and rectangular tub or tank; and Figure 6, a washer with a wooden
pan furnished with circular obstacles.
Figure 7 shews an apparatus formed of several spherical cap-shaped washers
actuated simultaneously by the same motive power; Figure 8 shews a washer with
two pans superposed one over the other, both on the same axis.
Figures 9, 10, and 11 shew threo forms of pans which I specially recommend, ono
(Figure 9) is hemisphorical, another (Figure 10) is a hemisphere prolonged by a
cylindrical part, and the third a sort of half ellipsoid.
Figures 12 to 18 are special arrangements of washers; Figure 12 represents a
washer furnished with a dividing rake (scen also in Figure 13); Figure 14 is a
washer with a dividing hopper and distributor; the bottom of the washer is
furnishod with strips of caoutchouc.
Figure 15 shews an arrangement differing from the preceding as to the washer
and the means of imparting motion thereto.
Figure 16 is a modification of the plate washer.
Finally, Figures 17 and 18 shew the employment along with water of a denser
liquid, such as mercury.
Referring to Figures 1, 2, 3, and 4, it is seen that the washer is essentially com-
posed of a circular wooden tub or tank a, the vertical sides of which are held
together by metallic hoops b, b, of a central pan c of copper or other suitable metal,
and of a support or pivot & placed concentrically with regard to the tub, and fixed
upon the bottom a¹ thereof.
The pan or spherical. cap c is as I have already said of copper; it is strengthened
all round the circle of the base by a ring (toron) of iron wire c", and fixed at the top
of the cap to a brass ring e which serves to fix the cap solidly to its axis f by means
of the screws with nicked heads e¹, e¹. This pan is more or less hollow, according to
the nature of the matters to be washed. The shallowest pan c, shewn in dotted
lines, is for fine matters, the deepest, c, for very fine, and the intermediate, c¹, also
shown in dotted lines, for tolerably fine matters.
The axis f is of brass of a length sufficient to extend out of the water and to
receive upon a square part formed thereon the double crank or handle m, m. This
axis is hollow to receive the iron support or pivot d which fits easily therein, and is
long enough to maintain steadiness of the movement of the pan.
The support or pivot d may be forged with a plate for fixing it solidly to the
bottom a¹ of the tub, or it may be connected by screwing (see Figure 3) or otherwise,
with a cast iron plate screwed or otherwise fixed to the bottom.
The part of the support or pivot d which enters the axis f of the pan is grooved
to reduce friction as much as possible; the axis f is also pierced with one or several
air holes f¹, and furnished with passages for conveying the lubricant to the rubbing
parts. The bottom of the pan is covered with a false bottom of the same metal
in one piece with the case which is prolonged to a little below the handles. This
false bottom constitutes the part which serves for making the collection, that is, the
removal from the water of the rich matters as soon as the washing is finished.
OPERATION OF THE APPARATUS.
The tub or tank a is filled with water so as to completely immerse the pan. By
the simple deposit of auriferous sands upon the bottom of the immersed pan (or
basin), the operator has caused the sands to lose immediately at least fifty per cent.
of their weight, whilst the gold has only lost one nineteenth of its weight. The rich
matters have now a density of eighteen, whilst the barren matters to be expelled
have only a density of about one. By the aid of a few slight alternate shakes the
mass of sand is evenly distributed and becomes circular. The operator then imparts

page_text: a movement of rotation to the pan (or basin) and consequently to the sands which
it contains. But as the water is not (at least immediately) drawn into the gyratory
movement, it opposes a resistance to the sands in their circular movement, and this
relatively inert mass of water performs the office of dividing agent; it extends,
classifies, and prepares the sands for the expelling action. If the operator then
accelerates the movement of rotation, a driving out and repelling action takes place
due to the centrifugal force, and the matters are thereby projected from the centre to the
circumference of the pan (or basin). But the light, that is to say, the barren matters can
alone traverse the mass of water and mount up the increasingly steep curve of the
spherical cap. In this operation the mass of water which fulfills the office of
dividing agent becomes to some extent a regulating agent by proportioning
(pondérant) the driving out and repelling action due to the centrifugal force and
necessary for the expulsion of the barren matters only.
It is seen that the barren matters only are expelled from the pan (or basin) and
fall outside. As for the heavy matters, they mount up a certain portion of the
curve offered to them by the pan (or basin) or spherical cap, and the distance they
traverse is proportional to their volume, to their weight, and to the speed of rotation
of the pan (or basin); thus the operator must produce a centrifugal action powerful
enough to effect the expulsion of the barren matters, but which must be absolutely
ineffective as regards the heavy ones, that is to say, the rich matters which he desires
to preserve.
The sands and barren matters will be removed from the tub by the bung hole h
placed near the level of the bottom a¹, and the rich matters will be collected by
raising the false bottom c* out of the water, or by any other suitable or convenient
means.
For continued working the circular form of the tub or tank a would not prevent
the drawing round of the water after working a short time, but I reserve to myself
the employment of all means suitable for resisting this action, whether by a rect-
angular tub or tank, as shown in Figure 5, or by any other combination.
Furthermore, for this purpose the operator first imparts to the washing pan a
movement of rotation, say from right to left, and when the water is drawn round
too much he reserves the motion, turning the pan in the reverse direction. In this
Figure 5 is shown by the dotted lines x, y, z, the form which it will be suitable to
give to the bottom a¹ of the tub for emptying out the barren matters. The pan is
commanded by a handle m, and it is furnished with a false bottom c³, which may
be removed for collecting the rich matters after washing.
Figure 6 only differs from the preceding arrangements in having the pan of wood
slightly hollowed and furnished with concentric projections which form obstacles to
the matters and facilitate their separation.
The washer, Figure 7, is composed of a rectangular tank a of sheet iron and of a
series of pans c, c, the axes f of which are prolonged above the water, and supported
in bearings in a longitudinal carrier p fixed to a metal frame arranged to carry the
driving apparatus, which consists of an axis n furnished with a fly crank vand
bevel pinions n¹, n¹, gearing with similar pinions fixed on the ends of the axes f of
the pans. These pans in turning in the same direction impress upon the water
currents in contrary directions, which are suited to resist the formation of continued
currents by the rotary motion of the machine.
In Figure 8 the washer presents the peculiarity of two superposed pans, the upper
and smaller one c receiving the matters to be washed, and the lower and larger
one c¹ receiving the matters rejected by the pan c, causing them to suffer a second
working, and separating the rich matters which have escaped from the first
operation.
The pans shewn above (except that in Figure 6) have for base a circle of smaller
diameter than that of the sphere; they are very suitable for working substances
where the difference of density and volume of the barren and rich matters is very
appreciable, for in that case the separation always takes place before reaching the
base of the pan. But when the densities and volumes differ but little, I propose to

page_text: employ hemispherical pans (Figure 9), hemispherical pans extended upwards by a
cylindrical part (Figure 10), and the half ellipsoidal form (Figure 11). I further
recommend these forms for all work which requires great care in the collection of
the rich and so to speak impalpable matters.
In certain cases water may be insufficient to effect the division of the barren
matters from the rich during the working of the apparatus; in that case there may
be mounted upon the axis of the pan (Figures 12 and 13) a rake, the teeth of which,
fixed upon the four (more or less) branches are inclined in different directions. A
handle or lever serves to raise, to put in placo, or to hold stationary the rake
whilst the apparatus is in motion.
The washer, Figure 14, has its pan c in the form of a spherical cap with a cylin-
drical raised part c¹ and the bottom furnished with strips of caoutchouc c¹ forming
circular channels to increase, if necessary, the adherence of the caoutchouc. I also
uso pans of caoutchouc which, being placed inside those of copper, present to the
matters during their elevation much greater resistance than the copper sides, the
sliding of the matters upon the caoutchouc taking place with greater difficulty than
upon the copper surface.
The matters to be separated are poured into the divider by the shoot k¹. Motion
is given to the dividor mechanically or by hand; water for facilitating the pre-
paratory division of the matters is also admitted into the divider (malaxeur) k.
Figure 15 shews instead of the spherical cap-shaped more or less hollow pan a
plate e perfectly flat, furnished with a more or less closely woven woollon cloth or
other fabric c. Motion is communicated to the plate by means of bevel gearing
applied below. This kind of plate may be suitable for washing gold scales or flakes
(paillettes d'or) and gold dust."
Figure 16 is a modification of the preceding separator plate in which it is repre-
sented of a conical form.
Figure 17 shews an immersed cast-iron pan supposed to be at rest, with a bath of
mercury suited to facilitate the separation of the barren matters from the rich by
amalgamation in certain cases, as for example, when operating upon very thin gold
scales or flakes (paillettes d'or).
Figure 18 shews the pan supposed to be in motion, the matters falling from the
shoot t to the centre of the mercurial mass, and afterwards caused by the centrifugal
force to traverse the whole surface of this mass; it is during this tangential travel
that the amalgamation and simultaneous separation takes place.
Having now described the nature of my said Invention and the manner in which
the same is to or may be carried into effect, I would have it understood that what I
claim absolutely as my Invention is, the use of a rotative circular washer, offering to
the exit of the matters the resistance of inclined planes, rough surfaces, or projections
acting under water or under any liquid whatever, and effecting the separation of
matters of different densities by the action of centrifugal force, substantially as
herein-before described and illustrated in the Drawings.
In witness whereof, I, the said Ernest Bazin, have hereunto set my hand and
seal, this Twenty-eighth day of September, in the year of our Lord One
thousand eight hundred and seventy-seven.