IMPROVEMENTS IN PURIFYING MIDDLINGS
Year: 1874

page_text: LETTERS PATENT to Charles Edward Whitmore, of Quincy, in the
County of Adams, and State of Illinois, in the United States
of America, for the Invention of "IMPROVEMENTS IN PURIFYING
MIDDLINGS."
Sealed the 29th May 1874, and dated the 19th February 1874.
COMPLETE SPECIFICATION filed by the said Charles Edward Whitmore
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 19th February 1874, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE. PRESENTS SHALL COME, I, CHARLES
EDWARD WHITMORE, of Quincy, in the County of Adams, and State of
Illinois, in the United States of America, send greeting.
WHEREAS I am in possession of IMPROVEMENTS IN PURIFYING
MIDDLINGS, and have petitioned Her Majesty to grant unto me, my
executors, administrators, and assigns, Her Royal Letters Patent for
the same, and have made solemn Declaration that I am the true and first
Inventor thereof.
NOW KNOW YE, that I, the said Charles Edward Whitmore, do
hereby declare that the following Complete Specification, under my hand

page_text: and seal, fully describes and ascertains the nature of the said Invention,
and in what manner the same is to be performed, in and by the following
statement, reference being had to the accompanying Drawings forming a
part of this Specification, that is to say:-
My Invention has for its object to improve the method and means of
treating that portion of ground grain called "middlings," for the pro-
duction of flour of a superior grade. To this end the Invention consists,
first, in an improved process for purifying the "middlings;" and
secondly, in the machinery for working the process in whole or in part.
For convenience of arrangement I will first describe the process, and
lastly the machine and its various modifications.
In treating the middlings according to my process they are passed
into a machine or machines provided with a spreader and feed trough,
by which they are distributed evenly into and across a bolt or screen.
By a peculiar motion of cams or other equivalent devices the middlings
travel rapidly over the bolt or screen, and are subjected to a blast of air
forced up through them to act upon the fine brown and fuzzy particles,
and hold them in suspension. The strong currents of air ascending
between the screen and sides of the machine remove these particles
and deposit them in one or more dust chambers or rooms. The tapping
motion imparted to the screen by the cams or other equivalent devices
raises the light brown particles to the top, and as the middlings pass
along the screen or bolt they are sifted through free from all impurities.
A portion of the screen extends outside the machine at both ends, and
that portion outside the feed end is covered with fine cloth or other
suitable material to admit of the light brown particles being raised to
the top before entering the machine to be treated by the air. That
portion of the screen or bolt extending outside the machine at the
discharge end is covered with heavy coarse cloth for sifting the coarse
middlings through into a hopper, from which they are carried to another
machine or machines, until all of the fine middlings are purified.
All the middlings that pass through the screen or bolt in the machine
are purified and ready for grinding, while that portion (if any) which
passes over the end is the poorest offal.
The very coarse middlings and heavy brown particles, generally
known as tailings, and which are wasted by other machines, require a

page_text: f
such impurities from the machine to the dust room, thus securing a
perfect separation without waste.
The last stage in my process is highly important, from the fact that a
portion of the middlings and the cuttings, commonly called tailings or
refuse, are almost of the same specific gravity, therefore as they enter
the suction machine from the blast machine a very light current or
suction is used. As the quantity of middlings decrease, however,
the remainder is subjected to a stronger current of air, thereby effecting
a perfect separation of all the middlings without waste.
A very important advantage of the process is that it does not require
any change in grinding, the ordinary or usual mode being sufficient ;
neither is a change in bolting required, the same cloths being used as
are employed in the common method of grinding and bolting..
Another advantage arises from the fact that the improved process of
purifying the middlings does not decrease the capacity of the mill.
The flour manufactured as above described is preferably mixed with
what is known as wheat flour, thus producing a different and far
superior grade of flour than has heretofore been placed upon the market.
I will now proceed to describe the machines by which the foregoing
or an analogous process is carried into effect, reference being made to
the accompanying Drawings. In the Drawings similar letters of
reference are employed to indicate corresponding parts wherever they
occur.
Figure 1 is a vertical longitudinal section of a suction machine;
Figure 2 is a transverse vertical section of the same; and Figure 3 is a
vertical longitudinal section, showing a modification in the arrangement
of the fans.
Referring to Figures 1 and 2 A is the frame, substantially built; B is
the screen, covered with wire and bolting cloth; C, are links for
suspending the screen frame from the sides of the machine; D is a
sectional fan for graduating the current of air passing up through the
bolting cloth; E is the main driving shaft for imparting motion to the
operating parts; F, are slides for closing the openings into the fan;
and H are cams for giving a vibratory movement to the screen.
The operation of the machine is as follows:-The middlings to be
purified are fed into the screen B, and carried forward by the vibratory

page_text: movement thereof, and the other operating parts. The middlings as
they enter the machine are subjected to a light current of air passing up
through them, a result obtained by having the first section of the fan
smaller than the others, together with the slides for closing the openings
In the fan. The next section of the fan is made larger, thereby
increasing the force of the blast, in connection with the adjustable slides.
The lower or last section is made largest, or of such size as shall create a
blast sufficient to move and carry off the brown particles. By this means
I effect a perfect separation of the valuable portions of the middlings
from the refuse matter.
In Figure 3 the fans are shown arranged transversely of the machine
and screen, so that the currents of air shall be drawn directly upward
from the sides of the screen to the end openings of the fans, and upward
and outward from all points between the sides. The air currents there-
fore are drawn up through the entire length of the screen, varying in
force according to the size of the fans, and the adjustment of end
openings by means of the slides. I is an opening in the side of the
machine (one on each side) below the level of the screen, for the
admission of air upward through the screen, and between it and the
J is a
machine, passing to the openings in the fan, as above described;
hoppered box for the pure middlings to fall into; and N is a conveyor
for removing the purified middlings out of the machine.
Figure 4 is a longitudinal vertical section of the blast machine;
Figure 5 is an end clevation of the same; and Figure 6, a transverse
vertical section. K is the frame of the machine, constructed -in a sub-
stantial manner; L is the screen, covered with wire and bolting cloth;
M are the links for suspending the screen from the sides of the machine;
and N is a blast fan arranged at the end of the machine, below the
screen for forcing a current of air into a tube or trunk O connected to
the mouth of the fan, and exending longitudinally of the machine under
the screen; P are openings in the sides of the air tube; and Q are
openings in its top, which are adapted to be opened and closed by
slides R operated by rods S, projecting through the end of the machine;
T is a triangular bar, placed over the openings Q, to prevent the
middlings from falling into the air tube, and for spreading the current
of wind as it escapes from the tube; U are partitions placed at intervals
across the machine under the bolt or screen for regulating the force of
the air blasts passing upward through the latter, and at the same time

page_text: permitting a heavier blast, if required, through any particular part of
the screen.
The machine being set in motion the middlings to be purified are fed
into the trough fastened to the end of the screen, thence into the screen.
As they enter the machine they sift through rapidly, the bran and brown
specks being prevented from accompanying them by the air blast from
the fan. The coarse bran moves off over the end of the end of the screen,
and the dust and fine particles are carried up and deposited in a dust
chamber. The fan being set in motion, the air is forced into the air
chamber and passes into a compartment under the screen, and thence
through the apertures in the air tube. The partitions are so arranged
that the air cannot pass from one section into another, thereby securing
in each section of the machine a sufficient current of air to remove the
brown particles according to their specific gravity. At the upper end,
where the middlings are light, a light blast is required, the openings in
the air tube being adjusted in proportion to the coarseness of the
middlings. The force of the blast is regulated by the adjustable slides
in all the compartments, so that the parts of the screen shall be
subjected to a stronger or lighter current, as the coarseness or fineness
of the middlings require.
Figure 7 represents a vertical longitudinal section of a modified form
of the purifier, combining both the suction and blast fans. W is the
frame or body of the machine, divided into two compartment X, Y, by
the vertical partition Z, and A' is the screen or bolt extending through
both compartments, so as to project somewhat beyond both ends of the
machine. The screen is suspended from the frame by the pivoted
hangers B¹. That portion extending outside the frame at the feed end
is formed into a tight smooth surface, upon which the middlings fall
from the feed trough C¹ secured to such extended portion. The screen
has a horizontal and at the same time a vertical movement imparted to
it by a ratchet wheel D¹, roller E¹, and springs F¹, in connection with
the hangers B'. The ratchet wheel is mounted upon the centre of the
driving shaft G¹, and the roller upon the end of the screen at the centre,
while the springs F¹ are fastened to each side of and under the screen at
the feed end.
When the machine is in operation the ratchet wheel acts against the
roller to throw the screen in a direction against the tension of the
springs, which, when the points of the cams slip off the roller throw the

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screen back again in the opposite direction. In this backward throw,
the rear end of the screen strikes against a strip W₁ of hard wood
fastened to the end of the frame by bolts or other suitable means.
sharp, quick, percussive blow is therefore given to the screen in a
horizontal direction, which causes the middlings to pass rapidly over its
surface to the lower or discharge end; and at the same time a vibratory
movement is given to the cloth to keep the meshes clear.
H' is a tube or receiver supported at the front end of the machine,
and extending entirely across its width, into which the middlings enter
through the opening I' by means of a spreader board, by which they are
spread across the entire width of the tube. As the middlings drop
down to the feed trough, a current of wind from the suction fan J¹at
the top of the tube passes upward through them, carrying off the lightest
fuzzy particles and cooling the middlings, which fall in evenly distributed
quantities along the entire length of the feed trough. The middlings
pass through perforations in the bottom of the feed trough, or over its
lower edge, so as to cover the surface of the screen with a thin layer or
coat.
The vibration in connection with the rising and falling motion of the
screen, as above described, imparts the same movements to the middlings,
thus permitting the wind from the blast fan L¹ and its perforated
trunk M to pass upward through them freely, thereby raising the
light brown particles and carrying them off through the opening N¹ at
the top of the compartment into a suitable dust chamber.
The pure middlings pass through the cloth into the hopper O¹, and
are carried off by the conveyor P¹ to the stone. That portion of the
screen which extends into the compartment Y is covered with cloth of
proper size to clean the coarse middlings, which, as they pass over the
screen are operated upon by a current of air from the suction fan Q¹ at
the top of the compartment, such air current being sufficiently strong to
remove the heavyer brown particles; that which passes over the end of
the screen is fit only for offal.
The trunk M¹ of the blast fan conveys the air blast into the com-
partment X through openings R¹. Above each of these openings is
placed a strip S¹ to assist in distributing the wind evenly into the

page_text: A small space is left between the edge of the screen and the sides of
the machine, through which the wind passes in a strong unobstructed
current toward the opening N¹, carrying out the fine dust as it is raised
from the screen by the air passing through the cloth.
Having thus described my Invention, and means by which the same 5
is carried into effect, I wish to have it understood that I do not confine
myself to the exact details shown and described, as the same may be
varied without departing from the spirit of my Invention; but what I do
claim is,―
First. The process of purifying middlings by first subjecting them to 1
a current of air passing upward through them; and secondly, by sub-
jecting the coarser middlings and heavy paticles to a current of air
forced or drawn up through the bolt or screen, in the same or different
machine, substantially as described.
Second. The process of manufacturing flour by combining or mixing 1
the purified middlings flour with the first grinding or wheat flour, sub-
stantially as described.
Third. A middlings purifier provided with a graduated sectional fan,
substantially as shown and specified.
Fourth. The graduated sectional fan of the purifier, provided with
slides for closing the apertures therein, substantially as described.
Fifth. A middlings purifier provided with openings between the sides
of the machine and screen, for the upward passage of an air current of
greater strength than the current passing directly through the screen,
substantially as described and for the purpose specified.
Sixth. The combination of a sectional fan within the purifier with a
vibrating screen, substantially as described.
Seventh. Two or more fans arranged transversely across the screen of
a middlings purifier, substantially as described.
Eight. A middlings purifier divided into sections or compartments
under the screen, substantially as described.
Ninth. An air tube connecting the mouth of the fan with the different
compartments of the machine, substantially as described.
Tenth. The slides for graduating the openings into the air chambers,
substantially as described.

page_text: Eleventh. The combination of the rods with the adjusting slides, sub-
stantially as described.
Twelfth. A middlings purifier provided with two suction fans and a
blast fan, substantially as described and for the purpose specified.
Thirteenth. A middlings purifier provided with two suction fans and
a blast fan, combined with the screen and feed tube, the fans operating
in distinct and separate chambers, substantially as described.
Fourteenth. A middlings purifier provided with two suction fans, a
blast fan, and a graduated wind trunk under the screen, substantially as
described.
Fifteenth. The feed trough in combination with the screen, substan-
tially as described.
Sixteenth. The screen of a middlings purifier having a vibratory and
rising and falling movement, substantially as specified.
Seventeenth. The vibratory screen of a middlings purifier, to which a
sharp percussive blow is imparted during the vibrations, substantially as
described and for the purpose specified.
Eighteenth. The ratchet wheel D¹, roller E¹, springs F¹, and wooden
strip W', combined with a suspended screen, substantially as described
and for the purpose specified.
In witness whereof, I, have hereunto set my hand and seal, this
Eight day of January, in the year of our Lord One thousand
eight hundred and seventy-four.
5 Witness,
0
CHARLES EDWARD WHITMORE.
(L.S.)
J. WARRACK,
British Vice Consul,
Chicago,
Ill.,
U.S.