Improvements in the Manufacture of Flour.
Year: 1888

page_text: Improvements in the Manufacture of Flour.
I, WALLACE WARREN, of Chicago, Cook County, Illinois, United States of
America, Manufacturer, 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 :-
In the manufacture of flour as heretofore conducted, the outer integument of
woody fiber composing the bran has as far as possible been separated from the inner
flouring substance of the grain by sifting or bolting, and by purifying or similar
processes. Such separation has, however, always been more or less imperfect, owing to
the fact that in the several steps or grinding, crushing or otherwise breaking down the
structure of the kernels of grain, the bran-coats and the interior substance are
crushed or operated upon together in one mass whereby the bran substance becomes
broken up into large and small scales, woody fibers, and fluffy fibrous particles, a
considerable portion of which are so comminuted that they pass through the meshes
of the bolting cloth with the flour from the inner grain substance, from which they
By reason of the presence of
cannot be separated by any means known to the art.
these fine impurities in the flour, millers have heretofore been obliged to make from
the same wheat several grades or qualities of flour containing more or less of the
impurities mentioned, besides obtaining a residuum of bran still containing portions
of the inner parts of the berry which can only be utilized as food for animals, or
discarded as offal.
The object of this invention is to provide an improvement in the so-called gradual
reduction process of milling by which there is separated or taken out of the product
of each break or reduction, all of the bran films or flakes, or scales of the bran
coats, or fluffy particles of the grain which the squeezing, crushing or bursting
or disintegrating action of the breaks upon the grain in its whole form or in its

page_text: broken condition have peeled, torn loose, or wholly or partially detached from each
other or from the kernel or particles of inner grain substance, whereby such bran
films, scales and fluffy particles are prevented from being subjected to more severe and
closer reductions, with the result of avoiding further comminution thereof and the
admixture of their fragments in the flour product.
In carrying out the method or process constituting my invention, I pass the
produci from such pair of break rollers between opposing surfaces, which are
relatively moved in such manner as to give a gentle rubbing action upon the
material passing between them. By this means, I detach or free from each other
and from particles of the inner grain substance, all loosely adhering bran flakes or
fibers which require only a slight or gentle abrasive action for their complete separa-
tion or detachment, without further crushing or reducing the grain. The product
is then sifted to separate out all particles of inner grain substance or middlings which
have been freed from the bran flakes by the action of the said rubbing device and
then subjected to an air blast to remove the bran fibers, scales, fluffy particles and
impurities which have been thus detached from parts of the grain by the action of
said rubbing surfaces before it passes to the next break or "reduction:
It is entirely obvious that when the particles of bran are allowed to pass on through
the successive breaks, as common heretofore, they are constantly being more severely
acted upon and more thoroughly comminuted by the closer action of each successive
reduction, thereby introducing into the flour fine particles of the woody bran coats,
which it is impossible to completely remove either by after purification of the mid-
dlings, or by bolting. By my process these bran particles and impurities are removed
as soon as they appear in the product of each break, and the action of the succeeding
break is confined to the still firin, unloosened and unreduced material. Any unnecessary
or undesirable action of the breaks upon the bran is thus avoided and mischief to
the flour product which commonly arises from the presence therein of the com-
minuted bran particles, is prevented in advance.
It is for some reasons preferable to subject the product of each break or reduction,
after it is sifted, to the action of an air-blast or suction before it is subjected to the
action of the rubbing surfaces; an advantage gained by the use of an air-current
at the time being that light bran flakes or particles which have already become
freed or detached from the inner grain substance by the action of the reducing
devices, are thereby removed from the material being operated upon, before the
latter is passed between the said rubbing surfaces. The employment of an air-blast
or suction in this manner is not, however, essential to the successful carrying out of
my process.
In the use of my process in the manufacture of flour, after purifications of the
middlings will usually be performed as heretofore, by the use of purifying machines,
such as are commonly used; but, by the employment of my process during the
reduction of the grain, such after purification will be rendered more perfect, and the
tailings thereof lessened in quantity and made more pure and available than hereto-
fore, and the capacity of the purifying machines employed will be increased, and
their work improved by reason of the absence from the middlings of the impurities
which the successive breaks or reductions now inevitably contribute to them and
which are removed therefrom in advance by my process, in the manner above
described.
A novel machine or apparatus adapted for carrying out the process above described,
is shown in the accompanying drawings. The main or essential part of such
apparatus consists of two opposing parts provided with rubbing surfaces which are
roughened or provided with slight prominences and depressions and which are so
moved relatively to each other as to act with a soft or gentle abrasive or rubbing
action upon the material passing between them. The apparatus also includes a sieve
for removing particles of the inner grain substance from the material passing from
the rolls, which sieve may be provided, if needed, with a brush for keeping its
meshes free, and an aspirating device for separating light impurities from such
material, as will hereinafter fully appear.

page_text: In the said drawings,
Figure 1 illustrates in side elevation a machine embodying my invention wherein
is included a sieve for acting upon the material after it leaves the break rollers and
before it reaches the rubbing rollers.
Figure 2 is a detail section taken upon line 2-2 of Figure 1.
Figure 3 is a detail section taken upon line 3-3 of Figure 1.
Figure 4 is a central, longitudinal section through the machine.
Figure 5 is a plan section taken upon line 5-5 of Figure 1.
Figure 6 is a fragmentary plan view showing one end of the machine.
In the machine illustrated in said drawings, Figures 1 to 6, A A¹ are opposing
rollers provided with roughened surfaces, as hereinafter more fully described, and
held adjacent to each other by light springs holding them together with a gentle
pressure and allowing them to easily open or spread apart and thereby act with a soft
or yielding rubbing action upon the material passing between them, in the manner
hereinbefore set forth. Said rollers are revolved in such manner as to carry or feed
the material between them while at the same time producing a rubbing action upon
the said material, and one of the said rollers has a longitudinal reciprocatory move-
ment, serving to produce a more thorough and complete rubbing effect upon the said
material as it is momentarily held between the adjacent surfaces of the rollers.
These motions of rollers are given thereto by devices hereinafter described.
B is the machine frame, which consists of corner posts bb and longitudinal beams ₁₁
and cross girts 22. Said frame is provided with separate metal castings B' B₁
affording bearings for the rollers A A', which rollers are located, in this instance, at
some distance below the top of the frame. C is a hopper located upon the top of the
frame B and adapted to receive material from the rollers or other reducing devices.
D is a screen, receiving material from the hopper C and which discharges into a
hopper D from which the material passing over the said screen, is delivered to the
rollers A A'. E is a second screen located below the screen D and receiving material
from said rollers A A', and discharging the same upon a series of inclined boards
FFF placed at its lower end. G is an exhaust fan focated at the top of the frame B,
and communicating at its inlet opening with a vibrating shoe or housing H which
surrounds the rollers A A' and supports the screen D and E, the hopper D1 and
boards F FF. The said housing E is provided with a partition H' extending from
its top to a point near the discharge end of the screen E and forming a chamber H
the upper part of which communicates with the inlet opening of an exhaust fan G.
The inclined boards F F F above mentioned are located in the bottom of the
chamber H2 in position to receive the tailings passing from the screen E. Between
said boards are provided air spaces f₁ through which air enters the chamber H2
and passes through the material falling from one board to another, for the purpose of
removing light impurities from such material. d d are inclined receiving surfaces
located in the shoe H beneath the screen D and sloping to a central transverse discharge
spout d¹, and ee are inclined surfaces located in the said shoe beneath the screen E
and similarly sloping to a transverse discharge spout e'. The said shoc H comprises
two side walls, to which the screens D and E and the other parts carried by the
shoe are attached, and end walls ¹³, the said end wall forming one side of the
chamber 2. The top of the shoe, in its part over the screen D, is closed by a
stationary wall upon the machine frame B which extends to and around the casing
of the fan G. The top walls of the chamber H2 of said shoe are fitted closely to the
adjacent under surface of the wall, thereby preventing any considerable inflow of
air at this point.
The boards F F F are inclined and arranged one below the other in such manner
that the tailings from the screen E fall from said screen to the board F, thence to
the board and thence to the board F, from which they pass out at an exit opening
or spout formed at the lower end of the wall 2. The air currents induced t..ough
the openings
between the boards F F F are controlled by means of flap
valve hinged at the hedges of the said boards on the lower edges of the
openings and adapted to swing at their free edges toward and from the upper

page_text: margins of said openings. The position of said valves is controlled by means of
clamp screws fff passing through segmental slots in the walls h h of the shoe
and engaged with the ends of the said flaps. The shoe is movably supported
upon the machine frame by means of vertically arranged flexible bars
(Figure 1) connected at their upper and lower ends with the upper and lower
longitudinal frame pieces 161 and connected at their middle parts with the sides of
the shoe H by means of pins which are secured in the sides of the housing and
pass through blocks upon the said bars hh. Reciprocatory motion is given
to the shoe H by means of a transverse horizontal shaft I provided with an eccentric i
and connected with a cross piece of the housing by means of a connecting rod i¹.
A regular and even feed of material from the hopper C to the screen D is produced
by means of a shaking bottom e in the hopper, which bottom is vibrated endwise by
means of a bell-crank lever a one arm of which is connected with the said sliding
bottom and the other which a crank-pin upon the shaft of the exhaust fan G
(Figure 6). The hopper D¹ is similarly provided with a longitudinally vibrating
bottom which is actuated by means of a bell-crank lever as the vertical arm of
which is attached to the said sliding bottom and the horizontal arm of which is
connected with an eccentric rod engaging an eccentric d³ upon a horizontally
arranged shaft K through the medium of which motion is transmitted to the
rollers A. A¹.
Devices for supporting and actuating said rollers A A¹ are constructed as
follows: The shaft of the roller A is mounted at its end in bearings jj upon the
upper ends of vertically arranged levers J J (Figure 2) which levers are mounted
upon pivots supported in the frame castings B' B. The said levers JJ arc
pivotally supported at points near their upper ends, and the lower ends of said levers
are engaged by expansible springs, said springs being connected with the machine
frame and acting upon the levers in a direction to throw the roller A toward the
roller A with a weak or yielding pressure, so that said rollers act with a gentle
pressure upon material passing between them.
The shaft K is located over the roller A and is provided with belt pulleys kk' and
with a sprocket wheel 10 over which passes a chain belt ", which belt also passes
over a sprocket wheel a² upon the shaft a of the roller A, and thereby gives motion
to said roller when the shaft is driven.
The shaft a of the roller A¹ (Figures 1 and 3) is mounted in stationary
bearings JJ upon the frame castings B₁ B¹. At one side of the machine the
bearing J is made considerably longer than the end of the shaft engaged therewith
and within the bearing is placed a spiral spring which acts endwise upon the shaft
and tends to throw the roller A' toward the opposite side of the machine. Said
spring is desirably arranged to act against an adjustable follower (Figure 5)
which is held in place by means of a screw shaft passing through the end wall of
the bearing. At the end of the shaft a', opposite to that last referred to, a sleeve J³
is placed around the said shaft a¹. Said sleeve J³ is provided with a spline engaging
a longitudinal groove in the shaft, thereby enabling the shaft to move end wise but
not to rotate within the sleeve. Upon said sleeve J³ is placed a sprocket wheel J.
K is a shaft arranged parallel with the shaft K and above the roller shaft al. Said
shaft K is driven from the shaft K by means of a spur wheel k upon the shaft K',
which spur wheel engages a pinion upon the shaft K. Said shaft K is provided
with a sprocket wheel k from which motion is transmitted to the sprocket wheel .J*
through the medium of a chain belt J. The rollers A A' are thus turned or driven
in opposite directions, the roller Al turning more slowly than the roller A by reason
of the difference in size between the spur wheel and the pinion ³.
An endwise reciprocatory motion is given to the roller A¹ by means as follows:
B (Figures 1, 2 and 3) is a metal yoke piece attached at its upper end to longitudinal
side piece of the machine frame casting B₁ by means of studs. Said yoke
piece B² extends over or past the end of the shaft a at some distance from the
latter. 1 is a vertically movable wedge located between the yoke piece B² and
the end of the shaft a². Said wedge is actuated by means of a rod or stem I the

page_text: lower end of which is engaged with a crank pin secured in a crank disk upon
the end of the shaft I bereinbefore described. Said wedge I is suitably held or
guided so as to remain in engagement with the end of the shaft a', devices for this
purpose herein shown consisting of a grooved bearing block pivotally supported
in the yoke B' and a notched bearing pin engaged with the inner edge of the
wedge and mounted to turn in a bearing recess formed in the end of said
shaft a. The spring hereinbefore described obviously acts upon the end of the
shaft a in such manner as to retain the opposite end of said shaft in engagement with
the wedge I. As said yoke is rapidly reciprocated by the action of the crank-pin
with which it is connected, a rapid longitudinal vibration will be transmitted to the
shaft and to the roller A' mounted thereon.
The approach of the rollers A and A' toward each other is limited by adjustable
stops A' A upon the frame, said stops being made adjustable to enable the pressure
to be regulated as desired. Said stops are. as herein shown, formed by set screws
passing vertically through the casting B' and engaging the bearings jj of the
roller A.
D and E indicate narrow transversely moving brushes, which may be employed
to keep clear the meshes of the screens A and E.
In
The rollers A and A', having roughened surfaces, as above described, may be made
to act with a suitably gentle and yielding pressure, either by making the rollers to
yield easily away from each other, as above set forth, or by providing the rollers with
cushioned or yielding surfaces, or by combining these features of construction.
the drawings the rollers A A¹ are shown as having roughened surfaces, but are
without any springs or other cushion devices beneath such surface. The necessary
yielding of the contact surfaces of the two rollers away from and toward each other,
for the purpose of giving a soft and gentle rubbing action upon the material is, in
the use of a roller of this kind, produced solely by the yielding of the springs which
hold the rollers in contact with each other. As illustrated more clearly in Figures B
and 4, the body of the roller consists of two semi-cylindric blocks which are provided
in their flat faces with recesses to receive the shaft a, and are held together upon the
shaft by means of flanged caps or disks provided with conical flanges which engage
correspondingly shaped end surfaces of the blocks. In the particular roller illustrated
the shaft a is provided upon its opposite sides with pins which enter holes in the
blocks for the purpose of holding said blocks from shifting upon the shaft, while the
disks are held in engagement with the blocks by means of longitudinal bolts passing
endwise through said blocks and provided with nuts upon their ends bearing
against the outer faces of the disks. The roller is in this instance provided with a
layer of leather, rubber or other flexible material, and an exterior layer of wire
cloth. The said layers are in this instance made in two separate pieces, each of which
covers the exterior curved surface of one of the blocks and is folded inwardly or
lapped over the adjacent margins of the flat surfaces of said blocks, in the manner
shown in the drawing, the said layers being held in place by the pressure of the
blocks upon their marginal parts, by which the edges of the layers are firmly clamped
and held.
I have found that find wire cloth gives a surface to the roller having a degree of
roughness producing favourable results, and such cloth may be used either with or
without a soft, yielding or compressible layer or layers beneath it. It is to bo
understood, however, that in carrying out my invention, rollers may be provided with
roughened surfaces made otherwise than the use of wire-cloth as above described,
and in my invention is not therefore restricted to a construction in which the rollers
are thus made except in the claim in which such construction is specifically set forth.
In the operation of the parts of the machine above described the material delivered
from the reducing rollers to the hopper E. passes from said hopper to the screen or
sieve D, and in passing over said sieve all the flour and middlings made by the action
of the reducing rollers is sifted out, and the remaining material consisting of the cracked
grain particles pass to the hopper D' and are delivered to the rollers AA. The screen D

page_text: in this machine takes the place of a separate scalping reel, such as is usually used between
breaks to separate out the product of the break, any flour and middlings made therein.
The advantage of employing a flat screen in place of a reel for this purpose, is that
the flat, vibrating screen acts more gently upon the broken fragments of grain, keeps
the flour more pure as it is thus much less liable to rub or break off small particles of
bran substance than is a reel, it being entirely obvious that any severe handling of
the grain before it reaches the rollers A A¹ will result in detaching the mixing with
the flour more or less of the bran particles and impurities which it is the object of the
machine illustrated to detach and separate from the flour product. I prefer, therefore,
to employ a flat vibrating screen, as screen D, by which the flour and middlings
made in a break or reduction may be separated before the product reaches the
rollers A A¹ without subjecting the product to any severe action, so that little or
none of the loosely adhering bran particles will be separated with the flour, but such
loosely adhering particles will remain upon the grain fragments until the said rollers
are reached and will be rubbed off or detached by the said rollers.
The material passing from the hopper D' to the rollers A A' is subjected to a gentle
rubbing or abrasive action, produced by the difference in the surface speed of the
rollers, and by the longitudinal reciprocatory motion of one of them. Such rubbing
action owing to the slight roughness of the rollers (which have no cutting action
whatever) serving to detach or loosen any loosely adhering or easily detached bran
particles, from the broken grain particles or fraguients, without in any degree flouring
the grain particles themselves.
The material which has been acted upon by the rollers A A¹, in the manner
described, falls upon the head of the screen E, through which passes such parts of
the material as is ready for the bolts or purifiers, while the detached bran particles
and light impurites which have been loosened or freed from the broken grain by the
action of the rollers passing over the screen with the remainder of the break material,
which latter as it passes over the several boards F FF, is subjected to a strong
air current in falling from one board to the other, whereby said impurities and bran
particles are separated or removed. After passing from the machine the material is
ready for and may be subjected to other reductions, or be otherwise operated upon
as desired.
I have shown in dotted lines at F³ an inclined screen which may be employed in
place of the boards F F F to support the material which the latter is being acted
upon by an air blast, and which may be set at the same inclination as the screen F,
or otherwise.
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: The improvement in the process of manufacturing flour in which the grain
is subjected to a number of reductions or breaks, which consists in subjecting
the material as it comes from each break, and before it passes to the next break, to the
action of yielding or cushioned, rubbing surfaces and thereafter separating from the
material thus acted upon, bran particles and other impurities detached by the action of
said surfaces, substantially as described.
2 The improvement in the process of manufacturing flour in which the grain is
subjected to several breaks or reductions, which improvement consists in subjecting
the ground or crushed product of each break or reduction to the action of cushioned
or yielding rubbing surfaces, then sifting the said material, and thereafter subjecting
the material to an air-current to remove detached particles of bran and other impurities,
substantially as described.
3: A device for the purpose specified, comprising two opposing, revolving, yielding
rollers having roughened working surfaces, substantially as described.
4: A device for the purpose specified comprising two revolving, yielding rollers,
one of which has a longitudinal, reciprocatory motion with relation to the other
roller, substantially as described.

page_text: 5: A machine for the purpose set forth, comprising two opposing, relatively
movable, yielding rollers, a screen or sieve receiving the material from said rollers,
and an aspirating device, substantially as described.
6A machine for the purpose set forth, comprising two opposing, relatively
movable, yielding rollers, a screen or sieve receiving material from said rollers, and a
second screen or sievo discharging to said rollers material passing over it, substantially
as described.
7: A machine for the purpose specified, comprising two opposing rollers provided
with cushioned or yielding surfaces, said rollers being movable bodily toward and
from each other, and a spring applied to throw the said rollers toward each other,
substantially as described.