IMPROVEMENTS IN THE ART OF MILLING AND IN MACHINERY THEREFOR, AND IN METHOD OF DRESSING THE ROLLS
Year: 1882

page_text: LETTERS PATENT to Alfred Julius Boult, of 323 High Holborn London, in
the County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN THE ART OF MILLING AND IN MACHINERY THEREFOR, AND IN METHOD
OF DRESSING THE ROLLS." A communication from abroad by Robert Lucas
Downton, of the City of Saint Louis, in the State of Missouri, United States
of America.
COMPLETE SPECIFICATION filed by the said Alfred Julius Boult at the
Office of the Commissioners of Patents on the 20th April 1882.
ALFRED JULIUS BOULT of London in the County of Middlesex, Patent Agent.
"IMPROVEMENTS IN THE ART OF MILLING AND IN MACHINERY THEREFOR AND IN
METHOD OF DRESSING THE ROLLS." A communication by Robert Lucas Downton
of the City of Saint Louis in the State of Missouri, United States of America.
In order that my Invention may be better understood I will first describe the
process of making Hour and its features that distinguish it from the methods or
processes heretofore used or that are used at the present time with the objections
thereto. The wheat after having been thoroughly cleaned is passed between a pair
of corrugated, round or sharp or flat fluted rolls, revolving at different speeds where
it is broken into small particles, the product of this grinding is then conveyed to a
bolt or reel, there to be separated, the fine flour and middlings that pass through
the meshes of the cloth are conveyed away and such as pass over the tail of the
bolt or screen are again passed between another pair of rolls to be again reduced
into finer particles, and so on through the entire process of reduction by alternate
crushing and bolting, and at each successive crushing the rolls are grooved suc-
cessively finer, this crushing being accomplished by rolls that revolve at differential
speeds, and in the same direction at their point of nearest approach of contact.
Now to fully describe my process, I use rolls revolving at differential speeds and
revolving in the same direction at the point of contact or breaking, said rolls being
fluted either parallel to the axis of the roll, or at an inclination to the axis, the

page_text: configuration of the flutes on the rolls being round, oval ogu form, or sharp in the
form of serrations, or of any other suitable form.
This part of my Invention does not relate particularly to the configuration of the
rolls or their general construction but is confined to the arrangement of each series
of round or oval or inclined or flat fluted rolls, with relation to the sharp fluted i
rolls. By use of the round fluted rolls, in the early stage of reducing, the grain is
broken into particles sufficient to liberate a large portion of the fine flour and
middlings; this operation may be continued through several grindings on round
fluted rolls or rolls working back to back so that the grinding is done on the flat
surfaces of the flutes when the sharp fluted rolls are substituted for the round flutes.
The degree of fineness of the flutes increases from the first operation of reducing
throughout the whole process, or flat fluted rolls varying in number from eight
flutes to the inch on the first to twenty eight or thirty on the last, though 1 prefer
20 as being fine enough. The advantage of using round flutes or inclined flat flutes
in the early stage and sharp in the finish, lies in the fact that the grain is mashed
or crushed into particles of sufficient fineness to liberate the middlings and fine
flour and by so crushing a large amount of the flour is crushed into the body of
the hull and branny particles, which when brought in contact with the sharp flutes
on the rolls used in the last stage of the operation is cut or scraped off, owing to
_thero being a sharp or cutting edge presented-to-said-particles_instead of a round 2
or crushing surface. Thus it may be seen that by this-arrangement.a large amount
of flour that has. heretofore been thrown away is saved. The flutes on the first
series of rolls may be parallel with or at an incline to the axis; the result will be
the same; but on the last series of rolls it is necessary that the flutes be at an
-incline-to-the-axis. I will now describe the machines preferably employed for
carrying out my process referring to Figure 1. In this machine-or-more-properly.
combination of successive machines-connected with one another. There are six sets
of rolls and six bolts shown, the first four sets of rolls having rounded flutes, and the
last two, sharp flutes. This arrangement need not be adhered to, as the quality and
condition of the grain may require more round fluted rolls and less sharp, or the 3
reverse, less round and more sharp fluted rolls, under all circumstances the sharp
fluted rolls being the last in the series. In this Figure A, is the first set of rolls
showing a convenient way of driving the same at differential speeds as described.
Arranged beneath these rolls is a suitable hopper opening into a conveyor a,
leading to the bolt B, to the tail of which is connected the spout b, that conveys 3
the tailings to the second set of rolls A' and so on. through alternate con-
veyors a, a, a, a, bolts B1, B2, B3, B4, B³, and spouts b', b, bs, 6s, to each set of
rolls A², A³, A', A, the product from the tail of the last bolt passing off to the
bran room or to any other desired point of the mill. The product from the tail of
the bolt Bs, passing between the sharp fluted rolls A* is there again reduced and 4
the bran scoured and cleaned, and afterward passed through the bolt B', the
product from the tail of this bolt is again reduced between the rollers A³, and the
product bolted. I do not confine myself to this number of sharp fluted rolls, as
one set might be sufficient to answer all requirements of one quality of wheat,
while another quality of wheat would require two or perhaps three sets owing to
the nature or condition of the grain. This may readily be accomplished by making
the shafts long enough so that the rolls can be reversed to run sharp if flat fluted
rolls or rolls having the face of the flutes inclined are employed. I am aware that
spiral fluted rolls have been used of successively increasing fineness from the first
stage of the reduction through the entire process. There are objections to this
construction and arrangement as the reduction is entirely accomplished by pressure,
that is the grain is compressed between the opposite flutes on each roll. This
reduction will answer for the first breaking up, when the objection becomes
apparent. As the grooves are progressively finer in the, successive pairs of rolls
and the particles of wheat are becoming smaller in the successive reductions the
floury particles and middlings are compressed on and into the hulls or bran and
cannot be removed by the use of rolls with rounded flutes and the rolls wear

page_text: faster. To the entire use of sharp or serrated flutes there are objections and by
their continued use cannot be obviated. The grain in passing between the rolls
is cut up, not crushed, and by a continued use of rolls with flutes of increasing
fineness, the grain is cut into finer particles at each reduction each particle being
part hull and part flour some of which being of such fineness as to pass through the
meshes of the bolts, and deteriorate the quality of the flour or leave it part
middlings and part bran. By the use of sharp edged fluted rolls throughout the
entire process of reduction the sharp edges of the flutes become dull that is to say
they are worn off by continued use and are then of no more advantage than the
round fluted roll. These obstacles are all overcome by iny arrangement of rolls,
round fluted first to mash or crush the grain, and sharp fluted last to remove the
floury particles from the bran. Having described the process and the machines
preferably employed for carrying the same into practical effect I will now describe
the various modes of dressing the rolls by which I have found that the best results
in grinding are obtained.
Referring to figures 2 and 3 which show in plan and section so much of a pair
of rolls R, R', as is necessary to illustrate the mode of dressing. This dress is
composed of grooves cut or otherwise formned on their peripheries like the teeth of
single cut files, and take in one roll a spiral direction to the left, and in the other
a spiral direction to the right, or reversely to each other, and the angle at which
the grooves are twisted or run may materially vary in different pairs of rolls, or in
one roll it may be greater than in the other, but I prefer to have them arranged at
an angle of about thirty five degrees to the axis of each roll. It will be observed
that the teeth or ribs formed by the grooves (taking the roll R' for an illustration)
upon the advancing side d, arc of casy bevel, but on the other side fall away
rapidly, the longer sides d, of the teeth or ribs constituting the active or grinding
surface of the rolls, and face each other as the rolls revolve. These grooved rolls
R, R', having the dress constructed as above described, operato in a manner
essentially different from the sharp ribbed rolls heretofore used in this class of
mills, the grain being operated upon in such manner that the starchy and glutinous
portions are merely pulverized, while the bran and germ are bruised and rubbed
and at the same time, by the spiral direction the grooves take on the periphery of
the rolls, the material is carried a short distance lengthwise of the rolls between
the ribs thus producing a rolling or twisting action on the bran and germ, and
thereby it is left in such condition as to be easily and readily removed from the
niddlings and flour, by the ordinary bolting process; while with the sharp ribbed
rolls heretofore used the bran and germ are cut into such fine particles that a larger
proportion will pass through the bolting cloth with the middlings and flour during
the bolting process, and thus require various subsequent manipulations to remove
thom. The number of grooves in the rolls may vary for different degrees of
fineness or different grades of work, or according to the substance to be reduced.
The flutes may be applied in straight lines longitudinally of the cylinders as shown
in Figure 4 or inclined or spirally as shown in Figure 2, and said flutes may be
rounded as shown in Figures 5 or sharp as shown in Figure 3.
I prefer to operate these rolls by gear wheels E, E, of different diameters so
as to drive the rolls at, different peripheral speeds. Belts may also be used to
accomplish the same result. My improved dress is also adapted for use in
connection with that class of mills having a roller and a concave, and the rolls may
be advantageously used for grinding other cereals. In the latter use of the rolls
the convex surface of the said cylinders is provided with grooves formed of an abrupt
side
and a bevelled side d, the latter terminating at the face of the cylinder with
what in a mill stone dress is termed a "trailing" or "feather" edge. These grooves
are arranged parallel to the axis of the cylinder, and with a narrow strip c, of the
face of the cylinder between them.
CV,
Having now described the invention and the manner in which the same may be
carried into practical effect, what I claim and desire to secure by Letters Patent is:
1st The herein described process of reducing grain to flour and middlings,

page_text: consisting in passing it through a series of sets of rolls revolving at differential
speeds, and in the same direction 'at their point of nearest approach of contact, and
of successive degree of fineness of dress, the first part of said series of rolls having
n dress of round or oval flutes, or inclined reversed sharp flutes and the latter part
of said series having a dress of sharp or serrated flutes arranged at an inclination
to the axis and through bolts arranged intermediate of each set and the succeding set
of rolls substantially as and for the purpose specified.
2nd In the manufacture of flour and middlings, a series of sets of rolls of
Buccessive degrees. of fineness of dress arranged to revolve in the same direction at
their point of nearest approach of contact and at different speeds; the first part of
said series of rolls having a dress of round or oval flutes, and the latter part of said
series of rolls having a dress of sharp or serrated flutes arranged to an inclination
to the axis, in combination with bolts arranged intermediate of each set and the
succeeding set of rolls, substantially in the manner as and for the purpose shown
and described.
3rd In a roller grinding mill the combination of the rolls R, R', having a dress
composed of sharp or rounded ribs or teeth running in a longitudinal inclined or
spiral direction the ribs or teeth of one roll running reversely to the ribs or teeth
-of-the-other_roll, with the longer sides of said ribs or teeth of easy bevel and
their opposite-sides of sharper bevel, whereby-the-corresponding longer sides
constitute the active or grinding surfaces of the rolls-substantially as specified.
4th In a roller grinding mill the combination of the rolls R, R¹, geared to revolve
at different peripheral rates of speed, having a dress composed of ribs or teeth
running in a longitudinal, inclined or spiral direction the ribs or teeth of one roll
running reversely-to-the-ribs or teeth of the other roll with the longer sides of said
ribs or teeth of easy bevel and their opposite sides of sharper-bevel, whereby the
corresponding longer sides of the ribs or teeth constitute the active or grinding
surfaces of the rolls, substantially as specified.
In witness whereof I the said Alfred Julius Boult, have hereunto set my
hand and seal this Twentieth day of April in the year of our Lord
one thousand eight hundred and eighty two.
ALEDED T BOULT

page_text: FIG. 2
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