IN MACHINES FOR PULVERIZING ORES
Year: 1884

page_text: I ALFRED JULIUS BOULT of 323 High Holborn in the county of Middlesex,
"IMPROVEMENTS
Engineer do hereby declare the nature of this invention for
IN MACHINES FOR PULVERIZING ORES" and in what manner the same is to be
performer, to be particularly described and ascertained in and by the following
statement:
The object of the invention is to effect the reduction of ore and other refractory
materials by means of concussion and attrition between the fragments or particles
and also to effect the separation and gradation of the pulverized material.
To this end the invention consists in a machine the essential features of which
are an external case or body and two oppositely rotating heads therein these heads
being constructed with arms hereinafter described in detail whereby material
admit ed, at the ends of the body is projected forcibly toward the middle so that
the two masses moving from opposite directions encounter each other with great
violence.
The blades also serve to force a powerful current of air through the machine
whereby the reduced portions of the material are discharged.
A receiving chamber combined with a deflector and spouts and automatic valves
serve to return the coarse material which may be discharged to the machine for
further reduction. The fine materials are delivered by the blast into a chamber
divided into compartments in which the material is divided according to fineness.
Referring to the accompanying drawings:
Figure 1 represents a vertical central section of the improved apparatus.
Figure 2 is a central vertical section on the line x-x.
Figure 3 is a perspective view of one of the rotary heads.
Figure 4 is a rear end view of the head.
Referring to the drawings A represents a rigid main frame which may be
constructed of wood or other material in any suitable form adapted to sustain the
parts hereinafter described.
B represents a case or body secured rigidly upon the middle of the main frame
and having the form or approximately the form of two truncated cones united at
their bases with their axes in a horizontal position. This body may be constructed
of wrought or cast iron or other suitable material and is preferably provided as
represented in the drawings with a lining a of chilled iron to protect the saine
from undue wear, the lining being either smooth or ribbed on the inner surface as
preferred.

page_text: The body is provided near its two ends with feed hoppers b opening through its
top as shown and is also provided at the center with a discharge throat o located at
the top When the materials are to be discharged in a condition so coarse that
they cannot be delivered by the air blast, a second discharge throat d may be
provided at the bottom as shown in the drawings this throat being closed by means
of a plate bolted thereon or by any other suitable means, whenever the machine is
employed for effecting a fine reduction of the material.
In the pposite ends of the body are mounted two rotary heads C and C¹ each
of which is carried on the end of an independent shaft D extending inward
through the end of the body and mounted in fixed bearings E on the main frame.
Each shaft is provided with a driving pulley F and the two pulleys connected by
belts G with corresponding pulleys H, on a driving shaft I one of the belts being
crossed as shown so that the two heads C C¹ are rotated positively in opposite
directions.
Each of the rotary heads consists of a hub or central portion provided with a
series of blades or arms e extending therefrom. The hub is located at or near the
outer end of the body and the arms are extended therefrom inward toward the
middle of the body their inner ends overhanging the hub and being entirely free
and disconnected from each other so that a large vacant space exists in the centre
of the body between the arms.
Each of the arms has a smooth surface and a spiral curvature, its outer edge
following approximately the inner conical surface of the body. It is to be noted
that the arms of each hend terminate at a considerable distance from the arms of
the other the intention being to have the central space between the opposing arms
of such width that the arms will not act to confine or crush the ore between them
the usual space allowed being about eight inches.
It will also be noted that the spiral surfaces of the blades are extended across
the periphery of the hub to its outer end in order that the material entering the
outer end of the body through the hopper b may pass directly in front of the
blades so as to be acted upon immediately by their faces.
It will be perceived that the blades have an outward inclination from the axes,
receding therefrom as they approach the middle of the body their free ends being
at a much greater distance from the centre than the ends which are attached to
the hub.
Owing to this construction and arrangement of the heads it is found that when
revolved in opposite directions the material entering from the hoppers 6 will be
acted upon immediately by the faces of the blades or arms.
The rotation of the
blades causes the material to be revolved therewith and the centrifugal force
developed maintains the material outward against the inner surface of the body
while at the same time the spiral curvature of the blades causes them to urge the
material in a horizontal direction toward the middle of the body. The result is
that the material started easily and gradually passes lengthwise over the faces of
the blades toward their overhanging ends, the speed of movement gradually
increasing until the material is finally delivered over the ends of the blades with
great velocity toward the opposite end of the body. The two masses of material
projected by the respective heads from opposite ends of the body encounter each
other at the middle with great violence, the impact and attrition between the
fragments causing them to reduce each other with great rapidity. Each fragment
is acted upon and thrown rapidly to and fro against the others until it becomes
powdered or finely granulated. To some extent the reduction of the material is
effected by the direct action of the blades or arms thereon and by impact against
the interior of the case, but this action is merely incidental and no special reliance
is placed thereon it being found in practice that the reduction is effected almost
wholly by the action of the fragments one on another.
I am aware that many machines have been produced for grinding and crushing
material between two revolving disks the disks being arranged in some instances to
maintain a constant pressure and grinding action upon the material between them

page_text: and in other instances to strike the material with a succession of rapid or percussive
blows. This apparatus differs from such machines in the important particular that
the blades do not act either as hammers or strikers or as grinding or crushing
heads. They serve on the contrary to take up the material with a smooth and
easy movement and to give a gradually increasing speed thereto so as to throw or
project the fragments in a loose condition toward the middle of the body and in
this particular it is believed that they differ in action from any other machine
hitherto known in the art.
In each end of the body around the central shaft and also around the hub of the
rotary head, if the same be formed with a hub as shown an annular opening of is
formed for the admission of air which is thus permitted to enter on all sides of the
rotary head Owing to the form of the blades and hubs and their rapid rotation
it is found that when the machine is in action a powerful current of air will be
drawn inward through the openings f and delivered after passing through the
center of the machine from the discharge opening c This air current passing
around and between the fragments of material carries with it from the machine all
the powdered or finely reduced material. In this connection the open central
space which exists within the body is of advantage for the reason that it permits
the air to act upon the material more efficiently than would otherwise be the case.
For the purpose of regulating the admission of air as well as for other purposes
the shafts which carry the rotary heads are adjustable longitudinally in their
bearings so that by moving them inward an increased space may be afforded for
the admission of air past the heads to the interior of the body Devices of any
suitable character may be employed to effect this longitudinal adjustment of the
shafts but I prefer to employ hand screws h mounted in the boxes which sustain
the outer ends of the shafts. These screws may bear directly against the shaft or
one or more plates i may be interposed as in the drawings. It will be observed
that the adjustment of the shaft in a forward direction has the effect not only of
increasing the air inlet but also increasing the distance between the outer edges of
the blades and the inner surface of the case, and of decreasing the distance between
the blades of one head and those of the other.
The discharge throat c is connected to an upwardly extending delivery pipe J the
upper end of which enters and delivers the material into a large chamber or casing
K which communicates through a pipe L with a settling chamber M. Within the
chamber K directly above the mouth of the discharge pipe J is secured a deflector N
of conical or other suitable form against which the outgoing air current laden with
ore is projected, the effect being to deflect the air and material in a lateral direction.
The air and the finer portions of the material held in suspension therein continue
their upward course, and escape through the pipe L at the top while the heavier
and courser materials which require further reduction descend by gravity outside
of the pipe J into a hopper O by which it is encircled. The hopper O is provided
with weight d valves P through which the material is discharged into conductors Q
leading to the respective feed hoppers of the machine.
Whenever the coarse material accumulates in sufficient quantity to overcome the
weights, the valves open automatically and the material passes from the hopper to
the machine.
The lower open end of the chamber K descends below the top of the pipe J and
enters the top of the hopper O, an annular space; being left between the mouths
of the chamber and hopper as shown for the passage of air. In practice it is found
that whenever this air opening is provided a much better and more satisfactory
separation of the material is secured.
In order to admit of variation in the size of the air passage j the chamber K is
connected to the hopper by means of vertical bolts q the upper ends of which are
secured to the chamber while their lower threaded ends are inserted through the
edge of the hopper and secured by nuts above and below the same.
The discharge pipe L opens into one end of the chamber M, the opposite end of
which is provided with an opening for the escape of the air This chamber is

page_text: divided by vertical partitions into a number of compartments in which the
material is deposited according to its varying degrees of fineness the coarse
material being first deposited.
The chamber is provided with a row of vertical partitions extending downward
slightly into the upper ends of the compartments and serving as deflectors for
directing the air current downward. It is found that these partitions assist
materially in causing the proper precipitation of the material.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed I declaro that what
I claim is:
1. In a machine for reducing ore by the concussion and attrition of the fragments
upon each other a case or body of increasing diameter from its ends toward its
middle combined with oppositely revolving heads having arms or blades substantially
such as described and shown.
2. In a machine for reducing refractory materials, a body having substantially
the form of two truncated cones united at their bases, and provided with the air
inlet at its ends and the discharge opening at its middle, in combination with the
two revolving heads having arms or blades overhanging a central space within the
body.
3. In combination with the body, and the revolving heads, the shafts movable in
a longitudinal direction, and means substantially as described for effecting their
adjustment.
4. In combination with the body and the revolving heads adjustable in an axial
direction the annular openings or air inlets encircling the shafts as described
whereby the adjustment of the shafts is caused to vary the admission of air.
5. In an ore reducing machine, a stationary case or body provided with air inlets
combined with revolving heads having smooth spiral blades substantially in the
form described and shown whereby the blades are caused to serve the twofold.
purpose of projecting fragments of ore against each other and of producing a
strong blast of air through the body for the purpose of delivering the reduced
material.
6. In combination with the body having the feed openings at or near its ends the
revolving heads each having a series of spiral divergent overhanging blades and
having the surfaces of said blades continued peripherally across the hub.
7. In combination with the reduction mechanism the receiving chamber, a
deflector and a hopper or receptacle to retain the partially reduced material.
8. In combination with the reduction mechanism the chamber, deflector and
receptacle the spouts and automatic valves whereby the partially reduced material
is returned to the machine for further reduction.
9. In combination with the reduction mechanism substantially as described, the
receiving chamber the hopper and the air passage into the lower end of the
chamber substantially as described.
10. In combination with the reduction machine having rotary heads adapted to
project the fragments toward each other and also to produce a blast as described
the setting chamber provided with the series of compartments substantially as
describ. d and shown.
11. In combination with the machine having two rotary heads adapted to project
the material and to produce a blast as described, a settling chamber connected
therewith and an intermediate chamber or hopper for arresting and retaining the
partially reduced material.
Dated thin 10th day of February 1884