Improvements in Grinding Mills.
Year: 1890

page_text: NOV., 1890-Accented
0721
a
ruth NOV., 1890-Accented 03110
VAUSITEUR
TROMB
STECIFICATION.
Improvements in Grinding Mills.
1, FRANCIS CHAPMAN, of 9 and 11 Fenchurch Avenue, Fenchurch Street, in th
City of London, Manager, (a communication to me from abroad by George Massey
of Pitt Street, Sydney, New South Wales, Engineer,) do hereby declare the nature o
this invention and in what manner the same is to be performed to be particularly
5 described and ascertained in and by the following statement:-
This invention relates to circular grinding pans for the further reducing of finely
divided and discrete materials and especially such as tailings, concentrates &c. also
for powdering cement making earths and mixtures and such like and for reducing to
finer particles any discrete substances. It has been specially devised in order to
0 produce a cheap and effective machine for that purpose.
These improvements in grinding pans consist first in the combination and arrange-
ment with a bottom or wearing surface of peculiar peripherical construction in a
circular pan of circular mullers adapted to travel upon and in contact or as closely as
possible in contact with said wearing surfaces and to be revolved upon their own axes
by contact caused by their own weight assisted by centrifugal force with the periphery
of said pan, secondly in the combination and arrangement with an upper grating or
sieve-like or perforated periphery upon a circular pan having circularly travelling
mullers or grinders of vanes or splashers travelling circularly and revolving upon
their own axes and preferably fitted up on the upper faces of circular revolving
mullers, and thirdly in the special combinations and arrangement of mechanical parts
hereinafter specifically set forth.
But in order that this invention may be clearly understood references will now be
made to the drawings herewith in which
Figure 1 is a sectional elevation of a grinding pan constructed according to these
mprovements.
Figure 2 is a plan partly in section.
Figure 3 is a plan of one of the mullers.
Figure 4 is a part cross section showing a modified construction of false bottom
ud muller.
Figure 5 also shows another modified construction of false bottom and muller.
A is a feed hopper, B a revolving carrier, B orifices around the centre of the
rrier B, C vertical spindle, D bevel wheel, E bevel pinion, F driving shaft,
and I driving pulleys, H the centre of pan or stem forming bearing in which
rtical spindle Crevolves, J coned shaped bottom of pan, K similarly cone shaped
se or renewable bottom its upper or grinding face being frustro spherical
upstanding flange or ring die which may be in one and the same casting
h K or separate therefrom. L is the central portion or sleeve of revolving mullers.
the renewable heads of mullers the under grinding faces being curved to suit K
which are secured to the base or flange of L by bolts and nuts m.
n which mullers revolve. P pivotted cross head attachment between the spindles o
the carrier B and which swings upon the pivot P¹. Qvanes or splashers upon
。 spindles
of muller. Router casing of pan made in one or more parts and secured to the
by bolts and nuts K'.
g. T discharge lip. U mercury well. V overflow pipe for oil from cup at
sgrates or screens. s frames for securing screens to
of H. W hole through which the contents of mercury well can be discharged.
hen the shaft F is set in motion by belts around pulley I' from any suitable
r the gearing of D and E revolve the vertical shaft C and with it the carrier B.
mullers travel around with the carrier B and as their points of support at the
ted cross head attachment with the carrier lie outside the vertical line the
ncy is for them to swing outwards due to gravity and in
Price 11d.1

page_text: peripheries impinge hard against the inside of the upstanding flange or ring die K
the adhesion between these thus brought about and slightly augmented by centrifugal
force due to their being carried around the axis e causes them to revolve upon their
own axes and as they are free to slide down the spindles o it follows that they will
press hard upon the renewable bottom K or any material which may be between them
according to the adjustment of the screwed hand wheels g upon the correspondingly
screwed upper ends of the spindles o. The inside of the flange or ring die K is in
Figure 1 shown vertical and the peripheries of heads of mullers coned to suit but as
shown in Figure 5 the peripheries of heads of mullers may be parallel and the inside
of the flange or ring K bevelled to match. Figure 4 illustrates an arrangement in
which part of the depth of the periphery of mullers has cogs b upon it which gear
into corresponding cogs d upon the upstanding flange K the remaining portion
of the periphery of the mullers and that of the upstanding flange K is left plain
in order to prevent the cogs running too deep in gear the object of these cogs
is to ensure the mullers revolving upon their own axes which may at some time if
not so arranged not be brought about if the material being ground is such as will
create friction between the grinding faces in excess of the adhesion between the
periphery of mullers and upstanding flange K. These cogs will apply similarly to
the mullers and upstanding flange shewn in all the other figures.
It will be seen from Figures 1 and 2 that the heads of the spindles o are fitted
with an adjusting gear as follows: ga hand wheel the hole in which is threaded to
suit the screwed upper end of spindle o. The boss of the hand wheel g has a number
of grooves or holes formed in it into which fits a spring catch f the lower end of
which is attached to the cross head P. h is a clamping bolt. k is a collar upon o.
a is a gland shaped cover secured into the upper end of L by bolts and nuts and
which is hollowed out to form a reservoir for lubricants, it will be thus understood
that the raising or lowering of the spindle o by the turning of the hand wheel g will
give a corresponding adjustment to the muller upon the face of the false bottom K
and after such has been arrived at the clamping bolt is screwed hard down this
gear admits of the important feature of adjusting each muller separately. It will be
noticed that there is considerable space between the underside of the collar k and the
bottom of the recess of L in which it works this space is for the purpose of allowing
the muller to lift in event of running on to any large hard substance and after passing
over same the muller settles down to its proper position.
To compensate for the reduction of weight due to the wear of the mullers heads
loose pieces may be clamped around the sleeves Lor a spring may be inserted between
the underside of P and top of L.
Figure 5 illustrates a modification of both the grinding or upper face of the false
botton K and also the underside face of the renewable beads of mullers M the former
being a frustum of a cone and the latter straight or flat.
The grinding face that is to say the underside of the heads of the mullers near the
outside are for a short distance in tipped or bevilled this forming an angle with the
face K for the purpose of gripping the small particles of materials and at and near
the inside edge of false bottom K the upper face is carried up to match the bevel
upon the mullers heads and as these two bevelled portions will wear away together
approximately their proper shape will be maintained at all stages of wear.
Now when previously finely divided material (say tailings) are fed with water into
the hopper A then fall through orifices B' into the interior of casing R finding their
way on to the face of K where they are seized between the face of K and the
revolving and travelling mullers and ground until sufficiently small and light to
be carried on to the surface of the water which will always be more or less above
the top of the flange K' they will be here met with by the splashers or vanes_Q
which will throw them with some considerable force against the screens S the
finer portion passing through the mesh and on to the lip T from where it may be
conducted to anywhere desired and the larger portions falling back to be further
reduced.
The liberated free gold is amalgamated with the mercury (contained on the

page_text: ougn
hole W.
from which it may when desired be drawn off by the discharge
It is to be understood that I have shewn the relative angular positions of the
various parts of the grinding pan with one another and with the vertical and
horizontal which is now believed to be host suited for the purpose in view yet I
do not confine myself to such as they may be varied without departing from the
nature of this invention as may also the number of mullers which may be either
more or less than four. It is to be further understood that I do not claim to
have invented revolving mullers travelling circularly in a pan with contact against
the periphery as I am aware that such has been used before for the purpose of
grinding or crushing materials between the periphery of the mullers and the internal
periphery of the pan but in this present invention all such crushing and grinding is
avoided as much as possible and the grinding is effected only by means of the face of
the mullers on the bottom of the pan, making use only of the contact between the
mullers and the inside periphery of the pan solely for the purpose of revolving the
mullers upon their own axes.
If desirable scrapers may be attached to the carrier B for the purpose of dragging
any material from the surface of the mercury in the woll U and distributing them
back on to the grinding face of K for further reductions.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First. In a grinding pan the combination and arrangement with a frustro spherical
grinding bottom or wearing surface of circular travelling mullers each having concave
faces corresponding to that of said bottom and having grinding contact by reason of
its own weight with the internal periphery of said pan substantially as horein
described and explained and as illustrated in the drawings.
Second. In a grinding pan the combination and arrangement with a frustro conical
grinding bottom or wearing surface of circular travelling mullers with flat faces each
having grinding contact by reason of its own weight on said bottom and having
contact by reason of its own weight with the internal periphery of said pan sub-
stantially as herein described and explained and illustrated in the drawings.
Third. In a grinding pan the combination and arrangement with a frustro-spherical
or a frustro-conical grinding bottom or wearing surfaces and circular travelling
nullers grinding thereon of a raising and lowering arrangement by which the weight
f each muller upon the grinding bottom may be adjusted substantially as herein
escribed and explained and as illustrated in the drawings.
Fourth. In a grinding pan the combination and arrangement with a frustro-spherical
r a frustro conica! grinding bottom or wearing surface and circular travelling
ullers grinding thereon of cogs upon the periphery of said muller gearing into
nilar cogs formed upon part of the internal periphery of pan substantially as herein
escribed and explained and illustrated in the drawings.
Fifth. In a grinding pan the combination and arrangement with a frustro-spherical
a frustro-conical grinding bottom or wearing surface and circular travelling
ullers grinding therein of vanes or splashers upon the upper side of the mullers and
upper grating or perforated or sieve-like periphery in said pan substantially as
rein described and explained and as illustrated in the drawings.
Sixth. The combination and arrangement of mechanical parts such as those set
rth and explained all together forming an improved grinding pan substantially as
rein described and explained and illustrated in the drawing.
Dated this 7th day of November 1890.