IMPROVEMENTS IN MILLS FOR GRINDING GRAIN
Year: 1876

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
MILLS FOR GRINDING GRAIN." A communication from abroad by Léopold
Macqué, of Paris, France.
Sealed the 11th July 1876, and dated the 20th January 1876.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 20th January 1876.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN MILLS FOR GRINDING GRAIN."
This Invention relates to improvements in mills for grinding grain in which the
bran is separated from the grits by concussion assisted by centrifugal force.
The grain is passed between a pair of truncated cones or conical discs (or they
may be plane discs) keyed on independent horizontal shafts, and receiving rotary
motion in opposite directions. The cones or discs are toothed and provided with
radial ribs and grooves, as hereafter described, on their working faces, and the
grain is fed in at the centre, and falling upon the one cone or disc is projected back
and forth from the one to the other until it reaches the circumference of the cones
or discs, where it is discharged.
The cones or discs may be made either of metal, porcelain, glass, or other suitable
material.
The Invention is illustrated in the accompanying Drawings, Figure 1 of which
shows a longitudinal section of one form of a mill, and Figure 2 a transverse section
of the same. A, Figure 1, horizontal shaft mounted in bearings and made of
reduced diameter for part of its length in order to turn in bushes in the hollow
shaft B, as shown. The truncated cone or conical disc or projector C is keyed on
shaft A, the corresponding cone or projector being keyed on shaft B. E, F, pulleys
for driving the shafts A and B in opposite directions. G, spout at which the grain
is introduced. H, path of the grain between the cones. J, screw for adjusting the
distance between the cones. At K is shown in dotted lines a pair of plane instead
of conical dises.
In Figure 2 C and K show respectively portions of the conical and plane
grinding surfaces. a, shows the cross section of one of the teeth or ribs; and
b, a longitudinal sectional elevation of the same; d, wire cloth through which the
grits pass; c, gap in the teeth to allow the grits to pass to the wire cloth.
[Price 1071

page_text: Figure 3 shows a transverse section of a mill arranged vertically in which one
cone is fixed. A, vertical shaft; B, driving pulley; C, cone keyed on shaft A;
D), fixed cone; E, feed hopper; F, rim to prevent the grain spreading; G, path of
the grain during the grinding operation; H, spout at which the product is
delivered.
Figure 4. shows a section of the cones reversed in position. I, eye of cone
through which the grain is supplied.
Figure 5 shows a plan of the cone."
Figure 6 shows a cylindrical mill chiefly used for grinding the grits. A, cylinder
having very fine longitudinal grooves; B, fixed grinding surface concaved to corre-
spond with A, and similarly grooved; C, feed hopper.
Figure 7 shows a mill with concave and convex grinding surfaces, to one of
which an alternate motion is imparted.
Figure 8 shows a mill with plane grinding surfaces, to one of which reciprocating
motion is imparted. In these latter arrangements the teeth are not radial, as
before, and have a longitudinal groove just below the summit, which is slightly
flattened, see Figures 9 and 10. The teeth on the fixed part may also be modified,
as shown in Figure 11, in which the teeth d are divided by one or more series of
cross grooves c into square, triangular, lozenge, or other shaped teeth. The depth
and distance between the grooves vary according to the desired quality of the
product. The same kind of teeth may be applied both to the flat and conical
grinding surfaces with the object of obtaining the finest quality and largest quantity
of grits, a coarser bran, and less dust. Teeth similar to those of the running cone
may also be applied to the fixed cone, and vice versa.
The height of the cones may be increased to any extent desired, even until they
become almost one cylinder revolving within another, and they may be revolved in
opposite directions whether placed vertically or obliquely.
Products of different quality may be obtained either by varying the speed of
the grinding surfaces, or the form, depth, and distance between the ribs or teeth, or
the same result may be obtained by varying the angle of the cone or employing
plane grinding surfaces, or increasing the height of the working surfaces, as shown
in dotted lines in Figure 3; or lastly, by varying the distance between the grinding
surfaces by means of the adjusting screw, Figure 1.
Many other means may also be adopted for varying the quality of the product,
thus, when the apparatus is disposed vertically, as in Figure 3, a coarser product is
obtained by placing the small end of the cone uppermost (and feeding in the same
manner as in the horizontal arrangement) than when the cones are reversed, as
shown in Figure 4, and the grain is fed at the centre of the inner cone. In this
latter case the grain being fed in at the smaller end of the inner cone is drawn
between the two conical surfaces and gradually raised while undergoing the
grinding operation, and ultimately discharged at the top of said cones.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on the
19th July 1876.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Patent Agent. "IMPROVEMENTS IN MILLS FOR GRINDING GRAIN." A communi-
cation to me from abroad by Léopold Macqué, of Paris, France.
This Invention relates to improvements in mills for grinding grain in which the
bran is separated from the grits by concussion assisted by centrifugal force.
The grain is passed between a pair of truncated cones or conical discs (or they
may be plane discs) keyed on independent horizontal shafts and receiving rotary
motion in opposite directions. The cones or discs are toothed or provided with
radial ribs and grooves, as hereafter described, on their working faces, and the

page_text: grain is fed in at the centre, and falling upon the one conc or disc is projected
back and forth from the one to the other until it reaches the circumference of the
cones or discs, where it is discharged.
The cones or discs may be made either of metal, porcelain, glass, or other suitable
material.
The Invention is illustrated in the accompanying Drawings, Figure 1 of which
shows a longitudinal section of one form of mill; and Figure 2, a transverse section
of the same.
A, Figure 1, horizontal shaft mounted in bearings and made of
reduced diameter for part of its length in order to turn in bushes in the hollow
shaft B, as shown. The cone or projector C is keyed on shaft A, the corresponding
disc or projector D being keyed on shaft B; E, F, pulleys for driving the shafts A
and B in opposite directions; G, spout at which the grain is introduced; H, path
of the grain between the cones; I, delivery spout for the ground grain; J, screw
for adjusting the distance between the cones. At K is shown in dotted lines a pair
of planes instead of conical discs.
In Figure 2, C and K show respectively portions of the grinding surfaces of the
conical and plane discs. shows the form in cross section of one of the teeth or
ribs; and b, a longitudinal sectional elevation of the same; d, wire cloth through
which the grits pass; c, gap in the teeth through which the grits pass to the wire
cloth.
Figure 3 shows a transverse section of a vertical mill in which one of the
cones is fixed. A, vertical shaft; B, driving pulley; C, cone keyed on shaft A;
D, fixed cone; E, feed hopper; F, rim to prevent the grain spreading: G, path
of the grain during the grinding operation; H, spout at which the product is
delivered.
Figure 4 shows a section of the cones reversed in position. I, eye of cone through
which the grain is supplied.
Figure 5 shows a plan of the cone.
Figure 6 shows a cylindrical mill for grinding grits. A, cylinder having very
fine longitudinal grooves; B, fixed grinding surface concaved to correspond to A,
and similarly grooved; C, feed hopper.
Figure 7 shows a mill with concave and convex grinding surfaces, to one of
which alternate motion is imparted.
Figure 8 shows a mill with plane grinding surfaces, to one of which reciprocating
motion is imparted. In these latter arrangements the teeth are not radial, as
before, but parallel, and have a longitudinal groove just below the summit, which is
slightly flattened (see Figures 9 and 10). The teeth on the fixed part may also be
modified, as shown in Figure 11, in which the teeth are divided by one or more
series of cross grooves into square, triangular, lozenge, or other shaped teeth, the
depth and distance between the grooves varying according to the desired quality of
the product. The same kind of teeth may be applied both to the flat and conical
grinding surfaces with the object of obtaining the finest quality and largest
quantity of grits, a coarser bran, and less dust. Teeth similar to those of the
running cone may also be applied to the fixed cone, and vice versa.
The height of the cones may be varied or increased to any extent desired, even
until they become almost one cylinder revolving within another, and they may be
revolved in opposite directions whether placed vertically or obliquely.
Products of different quality may be obtained either by varying the speed of the
grinding surfaces, or the form, depth, and distance between the ribs or teeth, or the
same result may be obtained by varying the angle of the cone, or employing plane
grinding surfaces, or increasing the height of the working surfaces, as shown in
dotted lines in Figure 3; or, lastly, by varying the distance between the grinding
surfaces by means of the adjusting screw, Figure 1.
Many other means may also be adopted for varying the quality of the product,
thus, when the apparatus is disposed vertically, as in Figure 3, a coarser product is
obtained by placing the small end of the conc uppermost (and feeding in the same
manner as in the horizontal arrangement) than when the cones are reversed, as

page_text: shown in Figure 4, and the grain is fed at the centre of the inner cone. In this
latter case the grain being fed in at the smaller end of the inner cone is drawn
between the two conical surfaces, and gradually raised while undergoing the
grinding operation, and is ultimately discharged at the top of said cones.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is, the herein shown and described im-
provements in mills for grinding grain, whereby the bran is separated from the
grits by concussion and centrifugal force, as set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set my
hand and seal, this Nineteenth day of July, in the year of our Lord One
thousand eight hundred and seventy-six.
A. M. CLARK. (L.S.)