Improvements in Grinding Mills.
Year: 1899

page_text: COMPLETE SPECIFICATION.
Improvements in Grinding Mills.
A communication from abroad by JOSEPH MARTIN SCHUTZ, of 910, 2nd Avenue
South, City of Minneapolis, County of Hennepin, State of Minnesota, United
States of America, Manufacturer.
I, JOIN CORRY FELL, of the Firm of Fell and James, of 1, Queen Victoria
Street, in the City of London, Chartered Patent Agent, do hereby declare the
nature of this invention, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
-
This invention relates particularly to improvements in grinding mills, that are
adapted for reducing, or pulverizing, materials such as sugar, salt, many kinds
of drugs, spices, ginger, seeds, cereals, and various minerals; and the object of
the invention is to provide a mill which will not clog or choke, and in which all
material fed into the mill will be reduced to any desired degree of fineness with-
out refuse or tailings.
In the drawings Fig. 1 is a vertical longitudinal section of a mill embodying
my invention; Fig. 2 is a front elevation and partial section of the same; Fig 3
is a side elevation of the feeder; Fig. 4 is an elevation, partly in section, of the
side of the feeder opposite that shown in Fig. 3; Fig. 5 is a detail showing the
adjustable blades in the separator; Fig. 6 is a detail of the means for regulating
the shake of the feeder; Figs. 7 and 8 are details of the magnetic separator
arranged in connection with the feeder.
In the drawings 2 represents the base of the machine, which is provided with
blocks or bearings 3, 3, for the main shaft 4. A driving pulley 5 is arranged on
the shaft 4. On the base 2, I support the cylinder 6, and the other parts of the
machine. The shaft 4 extends centrally into the cylinder 6. The grinding wall
of the cylinder is composed of the removable, corrugated shell S, and the inner
wall of the cylinder is preferably enlarged slightly towards its feed inlet end.
Beaters or breakers 7 carried on the end of the shaft 4 rotate within the cylinder G.
These beaters or breakers operate close to the corrugated shell 8, and effectually
pulverize any material that is fed into said cylinder. The beaters or breakers 7
preferably consist of blocks secured upon the discs 71 that are arranged upon the
shaft 4, a suitable collar being provided on the shaft against which the discs are
clamped by a nut screwed onto the end of the shaft, suitable washers being
arranged between and spacing the discs. 9 represents the feed and air-inlet trunk.
This trunk communicates with the body 6 by an opening 10 provided around the
shaft 4. The upper end 11 of the trunk is preferably enlarged to make room for
the automatic feeder 12, which is arranged beneath the hopper 13. This automatic
feeder 12 is not tightly enclosed in the trunk, but instead, the upper end of the
trunk is open for the free inlet of air, or other fluid that is employed as a carrying
agent for the pulverizing material within and passing from the body 6. Upon
the end of the body 6 is the separator portion of the machine. This part comprises
a shallow cone 14 of a pitch determined by the coarsest grade of material which

page_text: it is desired to produce with the machine. This cone is provided with a flange 15
that is secured to the end of the cylinder in such a way that it may be rapidly
removed therefrom and replaced by another cone of different pitch. For securing
the cone in place I prefer to employ the lugs 16, shown in Fig. 2, which are
fastened by pins or bolts upon the end of the cylinder. There is no particular
pressure upon the cone and the fastener need not be particularly strong. The
large end. 17 of the cone or separator is preferably of the same diameter as the
inner diameter of the cylinder 6, and the outer end or outlet opening 18 of the
cone is of greater diameter than the inlet opening 10 through which the air and
the material to be ground are admitted to the cylinder. 19 represents a return
duct arranged between the cylinder and the trunk and through which material is
taken from the front end of the cylinder and returned to the trunk 9 to be re-
ground. To prevent a heavy blast of air from escaping through the duct 19, and
thus back into the trunk 9, I provide a rotating valve 21 in the larger
or cylindrical portion 20 of the duct 19, and rotate said valve by
means of suitable connections 22 driven by a belt 23 from the main
shaft 44. The speed of the valve need be only sufficient to carry away the
material which is lifted into the duct 19 by the whirling air within the body. On
the forward end of the cone I preferably provide a bridge or yoke 24 which is pro-
vided with the sleeve 25 concentric with the cone. In this sleeve is arranged a
shaft 26 which may be adjusted to any desired position and secured by means of
a screw 27. On the inner end of the shaft 26, and within the cone or separator, is
a disc 28 preferably of less size than the outer opening, or end of the coné 18, and
adapted to limit the flow of air from said cone. I also prefer to provide upon the
shaft 4 a disc 29 that is of substantially the diameter of the large end of the cone.
This disc is located just within the end of the cylinder so that there is a narrow
annular space around the disc through which the material passes from the cylinder
into the large end of the cone. Pivoted upon the face of this disc are the blades
or wings 30 and a series of holes are provided in connection with each blade by
means of which the blades may be adjusted and held in any desired position upon
the face of the disc. These holes are preferably numbered so as to indicate the
different positions in which the blades may be set. These blades accelerate the
rotation of the air as it is discharged from the annular opening around the disc
29 and thereby increase the resistance to the outward flow of the air, and increase
the centrifugal force acting upon the particles carried by the air. The blades
therefore, interrupt the outward flow of the air so that the tendency is to stop the
outward progress of material and give it a transverse direction. When the blades
are arranged upon radial or nearly radial lines so that their edges come nearly to
the outer edge of the disc, their action upon material becomes so great that only
When the blades are turned so
the finest powder will escape from the cone.
that they stand transversely to the radial lines of the disc, leaving a wider space
between them and the walls of the cone, the air current is sufficient to carry out
the heavier, particles of material. Bolts and nuts or screws or other suitable
means may be employed for adjusting and holding the blades.
The feeder 12 consists of a trough open at its ends and hung upon suitable
links 31. These links are secured upon shafts 32 and these shafts are vibrated
from the shaft 22 by means of a counter shaft 33, an eccentric 34, eccentric rod 35
and connecting rod 36. An adjustable slideway 37 is mounted upon the end of
a shaft 38 and this shaft has secured to it a lever 39 by means of which the shaft
may be rotated upon its axis. A spring dog 40 upon the lever is arranged to
engage the teeth upon a stationary quadrant 41 and by this means the shaft may
be held in any desired position. A slide 42 is arranged in the slideway 37 and it
is provided with a journal 4:3 to which the ends of the rods 35 and 36 are pivoted.
By turning the shaft 38 and thereby varying the position of the slideway 37, the
movement of the rod 36 may be regulated and thereby the movement
of the feeder 12. In this way the feed of the material to the machine
may be regulated. I prefer to make the trough of the feeder of a brass plate,

page_text: and to arrange upon the underside thereof a series of bar-magnets 44 arranged
with their poles in opposite directions, so that any metallic substances such as
mails, screws or nuts in the material passing over the feeder will be taken out by
the magnetic action of the bars.
The operation of the mill is as follows: The material to be pulverized is
placed in the hopper 13 and is gradually and evenly fed into the trunk by the
shaking feeder, any metallic substances in the material being taken out by the
magnets. The material falls into the trunk 9 and thence into the cylinder or
body of the machine. The shaft 4 is rotated at a high speed, and the beaters,
therefore, rotate at a high peripheral speed and close to the corrugated shells
on the wall of the cylinder and thereby the material is pulverized. The beaters
create a strong suction of air downward through the trunk and outward around
the disc 29 and through the cone, the air being rapidly rotated and also urged
forward. The material after being ground or pulverized by the beaters is, led or
forced toward the cone and passes through the annular space around the disc 29
and enters the larger end of the cone. The rapidly rotating and forwardly moving
currents of air carry the pulverized material spirally around the wall of the cone
and as the particles of material move under the influence of centrifugal force, the
heavier particles are projected tangentially, and, striking the cone, are deflected
backward towards the body of the machine. This occurs at different points on
the cone according to the heaviness or lightness of the particles, and only those
particles that have less force than the onward moving force of the air are dis-
charged from the cone, and it is only necessary to regulate the onward or longitu-
dinal movement of the air currents to keep all but a certain grade of pulverized
material from escaping through the open end of the cone.
The rotation of the air as it passes from the cylinder into the cone through the
annular space around the disc 29. is accelerated, and the resistance to the outer
flow of the air is increased, and the centrifugal force upon the particles carried
by the air is also increased, by the action of the adjustable blades or wings 30.
The adjustable disc 28 does not interfere with the path or paths of the moving
material within the cone but restricts the final outlet opening to a narrow annular
space. The obstruction of the cutlet opening by means of the disc causes the
rotation of the air current, and therefore the amount of centrifugal force imparted
to each particle remains constant, and the centrifugal force depends upon the
weight of the particle. The heavier particles will be thrown from the supporting
air current and will impinge upon the lower or inner part of the cone and will
pass back towards the cylinder while the lighter particles move somewhat further.
forward in the cone, but as the conical surface more closely approaches the axis
of the rotating body of air the distance through which the particles must be
thrown to strike the cone is decreased according to the distance from the cylinder,
therefore, although the weight of the particles is less, it will meet with the cone
and be deflected backwards. This occurs with all particles whose weight plus
the constant centrifugal tendency imparted by the rotation is greater than the
onward moving force of the body of air. The lighter particles will escape contact
with the cone even at the extreme end thereof, and will be carried out of the cone
or separator and into a suitable settling chamber which may be employed in con-
nection with the machine. It follows, therefore, that with a given size of
annular outlet opening and a given speed of rotation to the mill, particles of a
regular size only will be discharged therefrom. As the rotary movement remains
the same, owing to the fact that the speed of the mill is constant, to change the
grade of the material discharged from the mill, the longitudinal velocity of the
body of air therein is either checked or increased to respectively increase or
decrease the fineness of material allowed to escape. This is accomplished by
As the disc 28
means of the adjustable wings 30, and by the adjustable disc 28.
is moved inward the annular opening between its edge and the cone is increased
in size and allows a freer outlet of the air, which, in consequence, would then
possess greater longitudinal velocity, and, in effect, the pitch of the spiral will

page_text: be increased, thereby diminishing the centrifugal action, as compared with the
longitudinal action, with the result that larger particles will escape through
the annular opening around the disc. As the disc is drawn out and the discharge
opening decreased in size, the air will have a greater rotative and less longitu-
dinal force and the output will be finer. The coarser material that is returned
by the conical deflector passes through the return duct and is then returned to
the inlet opening of the cylinder and passes again through the cylinder for further
reduction thereof. The conveyor or wheel arranged in the return duct prevents
the interruption of the whirling body of air and its action in the conical deflector.
If this conveyor or wheel were not used too much air would be allowed to exhaust
from the cylinder or body of the machine.
Having now particularly described and ascertained the nature of this
said invention and in what manner the same is to be performed; I declare that
what I claim is:-
--
1. The cylinder with the rotating beaters arranged therein, the conical deflector
into which the material passes from the cylinder, and the return duct.
2. The combination, with the cylinder and the conical deflector, of the disc 29
provided with the adjustable wings or blades 30.
3. The combination, with the cylinder and the rotating beaters, of the conical
deflector and the adjustable disc 28.
4. The combination, with the cylinder, the beaters and the conical deflector,
of the return duct and the wheel or conveyor located therein.
5. The feeder, consisting of the vibratory trough having open ends, mounted
upon depending links and adjustable means for shaking said feeder.
6. The bar-magnets arranged upon the under surface of the feeder-trough and
projecting to or beyond the ends of the trough.
Dated this 14th day of February 1800