Improvements in or appertaining to Middlings Purifiers.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in or appertaining to Middlings Purifiers.
A communication by WILLIAM DICKSON GRAY, of Milwaukee, in the County of
Milwaukee and State of Wisconsin, United States of America, Gentleman.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Bank Street,
Foreign Patent Solicitors, 6, Lord Street, Liverpool and 6
Manchester both in the County of Lancaster and 323 High Holborn in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
The object of this invention is to provide a machine in which the mechanism for
subjecting middlings or other grain products to an air purifying or aspirating
process is combined with the shaking sieve for further purifying the material, and
with dust-collecting mechanisms, the machine as a whole being so organised as to
possess great capacity in a comparatively small space, and so
tinuous circulation of the air through the purifiers and dust-catchers, thereby
utilising the same body of air continuously and effectually preventing the escape of
dust from the machine.
as to cause a con-
To this end is combined in one machine an aspirating mechanism of any approved
form, such, for instance, as a series of inclined shelves over which the material is
made to flow, subject to the action of ascending air-currents, and, in connection
with this aspirator, a dust-catcher of any suitable form is employed, by which the
dust-laden air rising from the aspirator is deprived of its dust and returned again
through the aspirator.
Below the aspirator, or in any other suitable position to receive the partly
purified material therefrom, a flat shaking screen is employed to further purify the
material, and, in connection with this screen, a dust-catcher and fan are provided
to cause a continuous current of air up through the screen, thence through the
dust-catcher, and again downward and upward through the screen in a continuous
course.
In the accompanying drawings are represented those details and peculiar arrange-
ments of parts which are found best adapted for general use; but it will be
understood by the skilled mechanic after a consideration of this Specification that
the details may be modified both as to form and arrangement without departing
from the scope of the invention.
Referring to the accompanying drawings :-
Figure 1 is a side elevation of the dustless combined purifier, a portion being
broken away in order to expose internal parts to view.
Figure 2 is a longitudinal vertical section through the centre of the machine.
Figure 3 is an end elevation of the head of the machine.
Figure 4 is a vertical cross section through the head of the machine on the
line 4-4 of Figures 1 and 2.
Figure 5 is a vertical section through the tail end of the machine on the line 5-5
of Figures 1 and 2.
Figure 6 is a vertical cross section on the line 6-6 of Figure 5, showing the
deflectors against which the air impinges in its descent toward the screen.
Referring to the drawings-
A, represents a rigid framework which may be of any suitable form adapted to
sustain the various operative parts hereinafter described. It is tightly enclosed so
as to form a trunk, chamber or casing, within which the contained air is con-
tinuously circulated as hereinafter explained, it being a special object of the
construction to prevent the ingress or egress of the air therefrom. At the head

page_text: end of this casing is a closed feed hopper C, into which the material to be treated
is spouted in the first instance, and from which it flows downward over an inclined
spreader-board c into the aspirator D, (Fig. 1) consisting of a series of inclined
overlapping shelves or boards d, with air spaces between them, the shelves being
mounted at their ends in a box-like frame, which is suspended by outside hangers
and reciprocated by connections from eccentrics on the horizontal shaft E in the
manner in which hoppers and sieves are ordinarily shaken. The purified material,
continuing downward over the lowermost shelf of the series, flows through a vertical
passage, into a hopper F overlying the head end of the flat, slightly inclined
screen or sieve G, constructed after the manner of the screens ordinarily used in
middlings purifiers and extending throughout the length and width of the casing so
as to divide the same into upper and lower chambers.
In the upper part of the machine, a horizontal shaft H is mounted, extending
from one end of the frame to the other, and carrying near its middle an exhaust
fan which communicates through a horizontal tube J with a chamber K, above
the aspirator shelves. This fan, kept constantly in motion, serves to produce a
constant current of air upward and through the aspirator, the chamber K, and
tube J, through the fan, whence it is delivered into an annular encircling dust-
catcher I, hereinafter explained in detail. A chamber M, communicating with
the receiving end of the tube J, is separated from the chamber K by the partition
rising nearer to the top of the machine with an air opening m thereover. The
chamber K is of greater sectional area than the spaces between the aspirator
shelves, and therefore the ascending volume of air is expanded and reduced in
speed to correspond, the effect being to re-deposit the heavier matters held in
suspension, while the dust, fluff and lighter impurities are carried over the opening m,
into the chamber M, and thence through the fan to the dust-catcher.
The dust-catcher is constructed as follows:-
A circular closed drum or chamber 1, encircling the suction tube J, is in turn
encircled by a cylindrical revolving screen 1, fixed to the periphery of and revolving
with the fan. This screen is encircled by a series of parallel annular chambers or
channels L, open on their inner sides next to the screen. Annular conical rings or
flanges are extended around the inner walls of the channels L, with spaces
between their edges. This series of chambers and the delivery end of the screen
communicate, through a descending passage O, with a transverse hopper P, at the
head of the machine, and intended to receive such dust and fine impurities as are
carried through the dust-catcher with the air. The dust-laden air, passing through
the fan, is driven outward through the annular spaces between the drum and the
surrounding screen, and, escaping through the screen, carries with it the dust that
passes into the annular chambers L, in succession, with an eddying or re-acting
movement. The result is that the dust is largely deposited in these channels,
while the air is returning through the annular spaces and through one chamber
after another, descends finally into the chamber P, and thence upward again
through the aspirator to repeat the course above described.
In order to prevent the accumulation of dust within the tube J, a spiral blade or
scraper q is connected by arms to the fan shaft, in order to sweep around the interior
of the tube J, and force the solid matters towards the fan.
In order to secure a uniform distribution of the material flowing to the aspirating
shelves, a flexible bar c', higher at the middle than at the ends, is mounted trans-
versely, near the lower edge of the spreader board c, in staples or similar supports,
which will admit of its being bent. A rod c² is attached to the middle of this bar,
extended to the outside of the machine and provided on its outer end with a thumb-
nute, by turning which the bar may be bent so that it will have a tendency to
throw or distribute the material sideways from the centre as it flows thereover.
This will ensure a uniform distribution of the material throughout the width of the
aspirator.
Attention is now directed to the shaking sieve and its adjuncts. The sieve will
be constructed and mounted in any ordinary manner, and driven by eccentrics or

page_text: any other customary appliance adapted to give it a longitudinal, lateral or
circulatory movement. Above this screen throughout its length, a vacuum
or suction chamber R is constructed, having inwardly sloping walls r, the lower
edges of which terminate directly over the edges of the screen, with which they
form a close connection through the intervention of wool or other soft material.
The upper and narrow side of this chamber communicates, through a grated
valve and an upright passage ³, with a second suction fan S, mounted on the
shaft H before mentioned.
The fan delivers through a surrounding dust-catcher T, similar to that before
described, into a passage U, extending downward and communicating in its turn
with two chambers V, lying outside of the walls of the vacuum chamber, and between
said walls and the outer casing of the machine. These chambers V extend the
entire length of the machine and communicate through the narrow openings along
the side of the screen with the chamber W thereunder. The action of the fan
causes the air to ascend continuously through the screen or sieve G, agitating and
purifying the material thereon and carrying the light matters upward through the
fan into the dust-catcher, by which they are received and retained while the
purified air continues its course downward through the passage U, and thence
forward through the passage V, which effects its uniform distribution, and finally
downward past the sides of the screen into the chamber W. Flowing inward from
opposite sides of this chamber, it ascends uniformly through all parts of the machine.
The dust which lodges in the annular chamber t of the dust-catcher is discharged
in the same manner as in the first catcher, by means of blades t¹, attached to and
revolving with the cylindrical screen serving to sweep the accumulated matters
upward from the bottom of the chambers and outward through an elevated side
opening t, into a closed receiving chamber or pocket t, a longitudinal conveyor-
screw X, which also receives the dust in like manner from the first catcher,
delivering it all, through a spout at the head of the machine.
A transverse conveyor-screw Y delivers the material lodging in the head
chamber P to the conveyor already described, so that the first named conveyor
serves to deliver all the fine material from the machine. The machine is provided
at the bottom with the usual gathering boards, conveyors and dividers.
In order to keep the descending air throughout the length of the machine, that
there may be a substantially uniform current through the screen at all points,
deflector-boards c, having upturned or inclined ends, as shown (Fig. 6), are mounted
at the tail end, in the path of the descending air.
It will be observed that, in the foregoing machine, the material is subjected to
two successive and independent purifications, and that each purifying apparatus is
provided with its own fan and circulating system, and that, although the dust laden
air is continuously and rapidly purified, there is no possibility of the blowing of the
dust from the machine into the surrounding atmosphere.
It will be observed that the various separating and purifying mechanisms are all
combined in one machine which, although of far greater capacity, occupies but
little more space than the ordinary sieve purifier.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, 1 declare that what I claim is :—
1. The combination, in a middlings-purifier, of an aspirator, a dust-catcher, and
fan arranged to circulate the air through the aspirator and dust-catcher, a sieve
arranged to receive partially purified material from the aspirator; a second dust-
catcher communicating with the sieve, and a fan arranged to circulate air through
the sieve and its dust-catcher.
2. In a middlings purifier, the combination of two purifying mechanisms, one
arranged to deliver to the other, each purifying mechanism including a dust-catcher
and a circulating fan.
3. In a middlings purifier, the combination of an external casing, a feed

page_text: mechanism, a series of aspirating shelves to which the said mechanism delivers the
material to be purified; a shaking screen to which the material is delivered from
the aspirator; a dust-catcher communicating with chambers above and below the
aspirating shelves; a fan to circulate the air in an upward direction between the
shelves and thence through the dust-catcher and the space beneath the shelves; a
suction chamber overlying the screen; side chambers opening above the sides of
the screen and a chamber thereunder; a dust-catcher communicating with the
suction chamber, and a fan arranged to induce a continuous circulation of air
upward through the screen and the suction chamber to the dust-catcher and
thence in a downward direction past the sides of the screen, that it may re-ascend
therethrough.
4. In a middlings purifier, the aspirator and the sieve to which it delivers in
combination with the suction chamber and side chambers overlying the screen; the
two dust-catchers communicating respectively with the aspirator and the screen,
and a shaft provided with two fans for maintaining currents of air through the
respective dust-catchers and their connections.
5. In a middlings purifier, in combination with the aspirator shelves, the under-
lying chamber, the overlying chamber, the annular dust-catcher communicating at
the top with the last named chamber and fan, and a passage extending thence to a
chamber beneath the aspirator.
6. In a middlings purifier, an aspirator comprising a series of shelves over which
the material flows.
7. In combination with a dust-catcher comprising a horizontal cylindrical screen,
a series of annular chambers or pockets and a fan turning on a horizontal axis,
said catcher communicating through a lower passage with the base of the aspirator
chamber.
8. In combination with the aspirator, the dust-catcher consisting of a cylindrical
screen, the annular chambers and the fan, a passage leading from the top of the
aspirator chamber downward to the centre of the dust-catcher; a central tube in
the latter, and rotary blades to prevent the lodgment of material in said tube.
9. In a middlings purifier, the combination of the shaking sieve, the overlying
suction chamber, the side chambers opening downward past the sides of the sieve,
the horizontal shaft carrying a fan and a cylindrical screen, the annular dust
receiving pockets or chambers encircling the screen, a passage leading from the
suction chamber to the fan and a passage leading from the fan and dust catcher to
the side chamber above the sieve.
10. In combination with the sieve, the overlying suction chamber and side
chambers; the horizontal dust-catcher communicating with the suction chamber,
the chamber leading from the dust-catcher to the side chambers, and a deflector
arranged in the path of the down-going air to distribute the same lengthwise of the
side chambers.
11. In combination with the aspirator, the screen and the two dust-catchers com-
municating with the aspirator and screen respectively, the dust receiving chamber
of the aspirator, its delivery conveyor and the side conveyor delivering the dust
from the first named conveyor and from two dust-catchers.
Dated this 24th day of July 1893.
WM. P. THOMPSON & Co.,
Agents for the Applicant.