IMPROVEMENTS IN METHOD OF AND APPARATUS FOR REDUCING ORES
Year: 1885

page_text: I, JAMES KENT GRIFFIN, residing at 229 Hancock Street, Brooklyn, in the
County of Kings and State of New York, in the United States of America
gentleman do hereby declare the nature of my invention for IMPROVEMENTS IN
METHOD OF AND APPARATUS FOR REDUCING ORES and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :-
My invention relates to a method of and apparatus or mechanism for the
reduction of ores and other substances by attrition and for the removal of the
reduced material from the line of attrition as fast as it is sufficiently ground, by a
current of air directed through alternate passages of a central conveyor directly
upon the line of attrition between opposing surfaces of the substance to be
reduced.
I will first describe the apparatus or mechanism which I preferably employ and
which forms a part of this invention referring to the accompanying drawings
forming a part of this specification.
Fig 1 is a front elevation of the apparatus.
Fig 2 a longitudinal vertical section thereof (the section of the shell being taken
on line X X of Fig, 3).
Fig 3 is a top plan of the shell and connections partly sectional.
The letter a indicates a shell or case made preferably of upper and lower sections
bolted together at the peripheral edges and forming a close tight-bottomed receptacle.
It is made open at the top and revolves as closely as may be beneath the cap-plate
or cover b. This cover is bolted to the machine frame and is provided with
openings for the passage of the material to and from the machine, as hereinafter
described Within the shell or case a is a rotating conveyor e which is fast on a
shaft f. This shaft is journaled in bearings in a tubular shaft or sleeve d and in
a lower step-bearing on the frame. A bevel gear-wheel c is fast on the sleeve d
and a bevil gear c¹ is fast on the shaft f so that suitable gears on a driving shaft
may mesh with gears c c¹ for rotating the shell a and conveyor e. independently of
each other. Preferably the gearing is so arranged that the shell a shall have twice
the rotative speed of the conveyor e and so that the shell and conveyor rotate
simultaneously in opposite directions.
The rotative speed of the shell and conveyor respectively may be varied to suit
the requirements of different classes of material and effective results have been

page_text: obtained by rotating the shell and conveyor in the same direction when the speed
of the shell considerably exceeds that of the conveyor, or the conveyor may remain
stationary the shell rotating around it as hereinafter described. The conveyor e
is divided vertically and radially preferably into four passages, arranged in opposite
pairs, two opposite passages g g being arranged so as to connect with the central
passage which opens into the hopper to conduct therefrom the crude substance
down to the outlets of the passages 9 These outlets face the inner periphery of
the shell a and have preferably a rectangular form and a marginal contour con-
forming horizontally to the curve of the shell. The edges of the outlets of the
passages g g may be formed of separate adjustable plates g' connected by adjustable
end plates y and movable outwardly from the center in parallel grooves in which
they are firmly held by wedging keys ga crowded against the end plates and
secured by binding screws g* shown by dotted lines passing through the key In
the construction of machines for different purposes, the space between the outlets
and the inside of the shell may be varied according to the quality of the material
to be compacted or consolidated therein as some substances require more space
than others for the formation of a firm annular wall as hereinafter described.
The compartments k. k of the conveyor e which alternate with the passages g g
are each divided centrally and horizontally by a plate m so that the space under it
connects with the passages p. p and the space above it with the exhaust pipes o o
to provide a passage around the plate m for a current of air, which may be forced
by an air blower or other suitable device. The relative proportions of the various
parts of the machine are varied to suit the size and quality of the material to be
reduced and may be of other suitable form as preferred.
I will now describe the second part of my invention which relates to the process
of reducing ores and other substances by attrition and it consists in carrying off
the reduced substances by passing a current of air directly upon the line of attrition
between opposing revolving surfaces of the material to be reduced.
It further consists in forming and maintaining a line of attrition between
opposing surfaces of the substance to be reduced by passing said substance through
a rotating conveyor and against an annular wall of the same substance firmly
compacted in a rotating shell and then carrying the pulverized substance off by a
current of air communicating directly with the line of attrition as will be herein-
after more fully described.
The object of this part of my invention is to provide a method of reducing
refractory ores and other substances better and more economically than has
heretofore been done and the said method may be carried out in apparatus and by
devices of various constructions but I prefer to use an apparatus of the construction
hereindescribed.
By reference to the operation of the machine I can now explain the distinctive
features of my improved method of reduction. The crude, substance is supplied
from the hopper h through the opening i into the passages g of the rotating con-
veyor and discharged therefrom by centrifugal force against the opposite inner
surface of the rotating shell a but without grinding effect until the shell is filled
to the edges of the outlets g meanwhile the centrifugal force developed by the
rotation of the shell, packs the material received from the conveyor e. into an
annular solid wall of sufficient firmness to resist the masses forced against and
ground upon it. The whole body of this annular wall need not necessarily be of
the material to be reduced. As the rotation of the shell and conveyor continues,
the greater solidity of the annular wall, due to the greater rotative velocity of the
shell, gives it a resisting power sufficient to pack the material forced against it, so
that the firm bodies of material in the shell and conveyor, respectively rotating in
opposite directions are solidly ground against each other on a well defined line of
attrition outside of and off from the periphery of the conveyor and within the
material.
The greater the excess of rotating speed in the shell, over the conveyor, the
more compact and solid will the respective bodies in the shell and conveyor be.

page_text: For some material it is better not to rotate the conveyor the attrition between the
mass in the conveyor pressing downward by its own weight and out against the
firm rotating annular wall in the shell being sufficient for the reduction desired.
This is effected by loosening the gear wheel c¹ from the shaft f and dropping it
out of connection with the driving wheel upon the step as shown by dotted lines
The solid impact and grinding of the material practically excludes the air from the
line of attrition while the grinding takes place thereby facilitating the reducing
process.
As the work of reduction progresses a current of air forced downward through
passages and under plates m immediately against the annular wall at its exposed
surface between the passages g acts as an air brush and by a rotating or whirling
motion sweeps the reduced material clean from the surface of the annular wall,
directly in the line of attrition as fast as the reduction takes place, leaving the
clean, sharp and unclogged surfaces of compact crude material to grind against
each other while the powdered product is carried off by the same current over
plates m upwards through the exhaust pipe o to any suitable settler or reception
chamber. The current of air may be changed or reversed and the reduced product
carried off in any other suitable upward or downward direction through or outside
of the conveyor as at the parts in the shell, so long as the air is separately
conducted directly to and upon the line of attrition. The force of the current of
air is adjusted to and determines the grade of fineness in the product, the lighter
the draft the finer the product, and vice-versa.
This is due to the fact that if the current of air is strong it takes up heavier
and larger particles than when the current is weak whereas if the current is weak
the particles will be ground over and over again till fine enough to be lifted by
the lighter draft.
I have demonstrated by continued use that with the shell and conveyor rotating
in opposite directions at low speed not exceeding from one hundred and fifty or
two hundred revolutions per minute very hard substances, as quartz and phosphate
rock can by my machine be pulverized in satisfactory quantities to the finest or
impalpable powder without intermixture of foreign substances or injury to the
machine.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. In an ore pulverizer a horizontally arranged conveyor having two or more
distinct openings for the passage of the material to be reduced and for the air to
carry off the same when pulverized substantially as described.
2. In an ore pulverizer the combination of the conveyor having openings for
the passage of the material to be reduced and for the air to carry off the same when
pulverized, an outer rotating shell or case and means for rotating the latter
substantially as described.
3. In an ore pulverizer, the combination of a revolving conveyor having openings
for the passage of the material to be reduced and for the air to carry off the same
when pulverized an outer rotating shell or case and means for rotating both the
conveyor and the shell substantially as described.
4. In an ore pulverizer the combination of a conveyor having ore and air
passages and an outer rotating shell or case, said conveyor and shell being so
adapted that the ore delivered through the conveyor will form, with the ore
adhering to the shell, a line of attrition on their opposing surfaces and means for
rotating the shell substantially as described.
5. In an ore pulverizer, the combination of a rotating conveyor having ore and
air passages and an outer rotating shell or case said conveyor and shell being so
adapted that the ore delivered through the conveyor will form with the ore
adhering to the shell a line of attrition on their opposing surfaces and means for
rotating both the conveyor and shell substantially as described.

page_text: 6. In an ore pulverizer the combination of an inner rotating conveyor, an outer
rotating shell, independent means for rotating the conveyor and the shell and a
hopper constructed and arranged substantially as described.
7. An ore pulverizer comprising the conveyor e having ore passages g g air
passages p. p cap b adjustable plates g¹ g' division plates m m shell a, shafts d
and f, gearing c and adjustable gearing c¹ all constructed and arranged substantially
as described.
8. In the reduction of ores and other substances by attrition, the hereindescribed
method of carrying off the reduced substances which consists in passing a current
of air directly upon the line of attrition between opposing revolving surfaces of
the material being reduced substantially as described.
9. The hereindescribed method of reducing ores or other substances which consists
in forming and maintaining a line of attrition between opposing surfaces of the
substances to be reduced by passing said substance through a rotating conveyor and
against an annular wall of the same substance firmly compacted in a rotating shell
and then carrying the pulverized substance off by a current of air communicating
directly with the line of attrition substantially as described.