Improvements in or relating to Sifting and Dressing Machines.
Year: 1896

page_text: Date of Application, 5th May, 1896-Accepted, 6th June, 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Sifting and Dressing Machines.
A communication by WILLIAM DICKSON GRAY, of Milwaukee, in the County of
Milwaukee and State of Wisconsin, United States of America.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.L.M.E. of The Agency for
Foreign Patent Solicitora, 6, Lord Street, Liverpool.. and 6, Baok Street
Manchester both in the County of Lancaster,. 1181 New Street, Birmingham in the
County of Warwick and. 322, High Holborn in the County of Middlesex, Cis
Engineer, do hereby declare the nature of this invention and in what. manner the
same is to be performed, to be particularly described pad ascertained in and
by the following statement:-
The invention pertains to that class of sifting and dressing machines for treating.
crushed or ground grain and like substances; in which a sieve-or a series of
sieves is arranged in a spiral form about a vertical axis, and provided with means
for producing a horizontal swinging motion or travel about an eccentric axis,
without rotation about its own.
The invention consists in various novel features, details; and cumbinations herein-
after set forth, whereby the machine is rendered compact and simple in construction,
highly efficient in action; and capable of handling at one- and the same time a
number of different grades or classes of stock.
The construction is such that different kinds or classes of material may be fed
through a central drum or trunk, containing any required number of separate
spouts or conduits, which may be so constructed as to deliver the several grades
of stock or material to the surface of the sieve at any point or points desired,
and to receive the material from the top of the sieve, or after it has passed
through the sieve and fallen upon the gatherboards, and convey or direct it to a
divided discharge box, from which each grade or product may be separately
discharged, or in which two or more different grades or products may be mingled,
as desired by the operator.
In the accompanying drawings-
Figure 1 is a side elevation of the improved machine with the casing or shell
broken away to show the interior;
Figure 2 is a horizontal sectional view on the line 2-x of Figure 1;
Figure 3 a similar section on the line y-y of Figure 1;
Figure 4 a vertical sectional view through. the trunk at the centre of the
machine, showing its use for feeding and delivering material to and from the
sieve or sieves ;
Figure 5 a detail view of one of the flights hereinafter referred-to;
Figure 6 a diagram or projection of the sieves and carriers, showing one of the
various arrangements thereof and of the feed and delivery. spouts or trunks;
Figure 7 a diagrammatic view illustrating the employment of two spiral sieves,
one above another;
Figure 8 a perspective view of a stepped or sectional sieve.
.
The details of the machine may in many respects be varied without departing..
from the spirit or scope of the invention, it being optional for instance, to
suspend the apparatus from a ceiling or overhead support, or within a special
frame; or to carry it upon uprights stepped at their lower ends in fixed
supports. These and other common features of construction may be varied as
the circumstances of the case suggest.

page_text: In the drawings a special frame for the machine is represented, and ordinarily
employed, and it is preferred to suspend the casing rather than support it from
below.
Such a machine is represented in Figure 1, in which A indicates a stout frame-
work of any approved construction within and from which is suspended a circular chest
or body B, by means of rods or hangers C having ball-and-socket or other universal
joints or bearings at their ends. Instead of these rods, straps ropes, chains, or
any equivalent hangers may be provided, though rods are preferred, and each rod
will advisably be provided with an adjusting thumb nut D, whereby the chest or
body may be levelled or adjusted as required.
The chest B comprises a feed box or chamber a at the top; a delivery box or
chamber b at the bottom; a tubular trunk c connecting said boxes or chambers,
and within which are the spouts or conduits through which the material treated is
fed to and delivered from the sieve and gatherboards; one or more spiral sieves or
series of sieves E winding about the trunk c; correspondingly arranged carriers
beneath the sieves, and an external shell or casing d, enclosing said parts. This
casing may conveniently be made of sheet metal, and will be removable as a whole
or in sections, preferably the latter.
A horizontal swinging motion is a circular path is imparted to the chest B by
the crank pin e of a wheel F, which latter is secured to a vertical shaft G journaled
in suitable boxes or bearings on frame A, and receiving rotation through bevel
gearing from a horizontal shaft H, carried in boxes on frame A. Any other
convenient drive may be adopted provided only a crank pin or eccentric be connected
with the chest and have its axis concentric with that of the chest.
A similar crank pin or eccentric f will be arranged at the lower end of the chest,
as shown, to ensure a like movement of the top and bottom thereof. Being sus-
pended or supported independently of the crank pins or eccentrics the chest moves
easily and but little power is required to rotate the shaft G.
It is important to prevent any tendency toward rotation of the chest about its
axis, as such motion would interfere more or less with the proper action of the
machine and throw the hangers out of position; hence the importance of placing
the eccentrics or crank pins with their axis coincident with that of the chest. It
is also important to have the weight distributed as equally as practicable on all
sides of the vertical axis for the same reason.
The feed box a is merely a circular chamber divided by partitions g into as
many compartments as may be desired, beiug in any case equal to the number of
grades or classes of stock intended to be handled by the machine.
In some
cases, as where two or more spiral sieves or series of sieves are employed, it
may be found expedient to increase the number of partitions and consequent
compartments.
Each compartment is provided with a feed opening in its top which may be large
enough to receive a feed spout and permit play of the chest without disturbing
such spout; or which may be furnished with a length of flexible feeding spout h
The latter arrangement is preferred.
The partitions are arranged radially and extend inward to and abut against a
central pipe or tube j concentric with the tubular trunk c, the partitions extending
downward through trunk c, and the spaces between them forming vertical spouts or
conduits i through which material may be fed to and delivered from the sieve or sieves
or any portion thereof, as indicated in Figure 4. For the purpose of giving adequate
strength and securing close joints, filling pieces k are worked in between the
partitions and against pipe j, thus forming a wooden tube or core about the metal
pipe j.
The delivery or discharge box b is or may be constructed in the same manner,
the feed box, discharge box and intermediate trunk with its partitions and core
producing a very strong and rigid framework to support and carry the sieve or
sieves and gather-boards or carriers.
Projecting radially from trunk c are arms w arranged at equal angular distances

page_text: about the vertical axis of the trunk and varying in elevation progressively around
the trunk, so that a line connecting them would describe a spiral or screw winding
about the trunk. The arms are grooved in their side faces to receive tenons or
tongues of sieve frames m, or of carrier or gatherboards n, both of which are of
segmental shape and adapted to slide freely into the spaces between two arms.
The arms being at slightly different elevations, the sieve frames and the gather-
boards or carriers will each incline slightly from the horizontal, and a continuous
series of these frames, or boards, or frames and boards will produce a spiral plane,
similar to a deeply cut screw thread, winding about trunk c.
The segmental shape of the sieve frames and of the gatherboards causes them to
fit snugly between the arms to and to fill the spaces completely, so that no crevices
of any size are left in which material might lodge.
As there is naturally some tendency for the material to work outward to the
circumference of the sieve, owing to centrifugal force, it will be found expedient
in some cases to arrange the arms w with their outer ends slightly higher than
their inner ends, thereby giving the sieve or sieves a slight inclination downward
toward the trunk c. This inclination will be greater or less according to the
dimensions of the machine, and to the rapidity and amplitude of the revolutions of
the crank pin or eccentric by which it is actuated.
The casing d would in any event prevent material from working over the
circumference of the sieve, but there would be a tendency of the material to bank
up against the casing in the absence of provision against it.
Whether the sieve be thus inwardly inclined or not, it is desirable to provide
means for shaking up the stock and more evenly distributing it over the surface of
the sieve than would be the case were the entire sieve made smooth on its face.
These objects are attained by means of flights or blades o, carried by the arms w,
and rising vertically therefrom in planes deviating somewhat from right angles to
the axes of the arms, as shown in Figure 3. These flights may be most conveniently
made of metal, and may be made adjustable to vary their angle of inclination to
the bars k, or fixed permanently in place, as deemed best.
A convenient construction is illustrated in Figure 5, where the flight is represented
as consisting of the blade o, formed upon or secured to a circular disc p, having a
stem g, threaded at its lower end to receive a fastening nut r. A circular socket
is bored in the arm w to receive the disc p and permit it to come flush with the
upper face of said arm, and with a hole to receive the stem g, the parts being
seated in position as illustrated in Figure 5, and made fast by nut r, at any
desired angle. Any equivalent means of application or adjustment may be
adopted.
In practice it is found advantageous to arrange the flights a distance apart
approximately equal to the throw of the crank pin or eccentric which imparts
motion to the machine, though the invention is not restricted to this or any other
specific distance. As the stock passes over the sieve and between the flights they
shake it up, turn it over, and cause such particles as might otherwise float or
remain on top of the layer to fall through the surface of the sieve. Thus if break
stock is being handled, any middlings which might float upon the top of the bran
will be shaken out and brought down to the sieve.
It is particularly to be noted that these flights do not propel the stock, nor do
they retard its travel, their position being such as to have neither the one effect nor
the other to any appreciable or material extent; but they serve in a measure to
direct the material, and especially to distribute, shake up, and loosen the mass.
Applied as shown, they are found greatly to increase the capacity and efficiency of
the machine.
It has been stated that the trunk e is divided by partitions into compartments
which constitute feed and discharge spouts or conduits. This feature of construction
calls for further explanation, being in fact a very important characteristic of the
machine.
By reason of this construction the material can be carried to and from the sievés

page_text: without any external spouts or conduits between its head and its base, and without
carrying any spout, chute, or conduit through any of the sieves, where their
presence would interfere with the proper travel of material, and reduce the sifting
surface.
Upon referring to Figure 4, the general plan of these feed chutes, spouts or
conduits will be readily understood, it being explained that the arrangement there
shown is merely illustrative and may be varied as desired.
At the left hand side of trunk c the compartment of the feed box a through
which the section is taken, opens and delivers into a vertical spout or chute i
which is provided with a diaphragm a short distance below its top, and with a
lateral opening t just above this diaphragm, through which stock can pass to the
sieve. At a lower point, a second lateral opening u is formed through which
material (tailings) may pass from the sieve into the lower part of the chute or
conductor and thence to the discharge box 6, whence it will. escape through a
suitable outlet to a flexible spout, as indicated.
A similar arrangement is illustrated at the right hand side of the central trunk,
with the difference only that the openings are at different levels.
In Figure 1, t indicates a feed or inlet opening, and u an outlet or discharge
opening, between which is placed a radial board v. Such a board is used just
below or after every discharge opening, and just above or before every feed
opening, to separate the different materials upon the sieve on opposite sides of the
board.
Figure 6 is a plane projection or diagram such as is prepared by mill designers,
illustrating one flow plan, or order of separations, the numbers at the right and
left indicating where the spirals would join, and the numbers on the blocks or
sections indicating the grades of cloth employed for this particular flow plan. It
is of course understood that there may be almost endless variations, according to
the views of the miller, class of grain handled, season of the year, atmospheric
conditions, capacity of mill, size of the machine, and the like.
Briefly following out the diagram, first break stock falls upon the head of the
long spiral sieve, is worked over five sections of No. 18. cloth, and the tailings
there encounter a stop board v, which terminates their travel and causes them to
enter a passage of the central trunk,, through which, they fall to the first break
tailings compartment of discharge box b. The screenings consisting of flour and
middlings in flour milling, from these first five sections travel along the imperforate
carrying or gatherboards n, which are unnumbered in the diagram and are carried
over fourteen sections thereof, whence they are delivered upon sieve sections
clothed with number 11 cloth. After passing over many sections of 11 cloth and
about the same number of sections of 12 cloth, the tailings,. being the middlings
from this product, finally encounter stop board v near the foot of the sieve.and are
carried inward to the trunk to be delivered to the discharge box.
The material passing through the cloth, being the flour, is also carried to the
trunk to be delivered to the discharge box separately, if desired, or it may be
mixed with the product of another break.
The second and third break stock are handled in a similar manner, as will be
readily understood upon referring to the diagram. Further explanation is deemed
superfluous, since the course of each may be varied as described.
By making the sieve of removable sections, the cloth may be changed in a short
time to suit the work in hand, and repairs may be quickly and easily made.
In Figures 1 to 7 inclusive, of the drawings, a sieve is shown and referred to in
the description presenting a smooth or unbroken surface, except as to the flights,
and such a sieve is preferred for various reasons; yet this mode of feeding sieve
machines of this class may be adopted on any form of sieve where central feed and
discharge are desirable. Figure 8 illustrates the invention embodied in a sectional
or stepped sieve.
As indicated above, two or more spiral sieves winding about the central column
one above another, after the manner of a double or multiple threaded screw, may

page_text: be employed, and this feature istof very considerable importance: for the reason
that it is necessary to give a certain minimum pitch or inclination to the sieve
which involves the separation of:successive turns of the sieve to a greater distance
than is necessary for the reception of the gather-boards and the proper-travel of
the material under treatment. It will be seen that where such unnecessary'space
exists, it is entirely feasible to introduce an extra screen or sieve; or in some cases
more than one extra sieve, thus..utilizing to the utmost the space within the chest
or casing.
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, I declare that what I claim is :-
1. In a sifting machine,. the combination of a central tubular trunk, provided
with a lateral outlet for escape of material; a sieve winding spirally about said
trunk from an upper to a lower level; and means substantially such as described
and shown for imparting bodily horizontal motion to the sieve and trunk in a
circular path.
2. In a sifting machine, the combination of a tubular trunk; a sieve winding
spirally about said trunk; a board or stop extending across the sieve; and an
opening through the trunk in rear of said board, whereby the material is directed
from the sieve surface into the trunk.
3. In a sifting machine, the combination of a central tubular trunk; a sieve
winding spirally about said trunk ; diaphragm extending across the trunk; an
opening above said diaphragm through which material may pass from the trunk to
the sieve; a board or stop extending across the sieve surface and serving to limit
the travel of material upon its surface, and an opening through the trunk below the
diaphragm and above or in rear of the stop board, whereby material is enabled to
pass from the sieve surface into the trunk.
4. In a sifting machine, the combination of a central trunk having independent
longitudinal passages or compartments; a feed box at the upper end of the trunk
provided with compartments corresponding with those of the trunk; and a sieve
winding spirally about the trunk below the feed box, said trunk being provided
with lateral openings for the passage of material from its compartments to the
sieve.
5. In a sifting machine, the combination of a central trunk having independent
longitudinal passages or compartments; a feed box at the upper end of the trunk
provided with compartments corresponding with those of the trunk; and a sieve
winding spirally about the trunk below the feed box, said trunk being provided
with lateral openings for the passage of material from the sieve into the trunk.
6. In a sifting machine, the combination of a feed box divided into compart-
ments; a central trunk extending downward from the feed box and similarly
divided; a discharge box at the lower end of the trunk provided with compartments
corresponding and communicating with those of the trunk; diaphragms extending
across the compartments of the trunk; a sieve winding spirally about said trunk;
lateral openings through the walls of the trunk above and below the diaphragms, and
boards or stops extending across the sieve immediately below the lower openings of
the trunk, substantially as and for the purpose explained.
7. In a sifting machine, the combination of a chest or casing; a central column;
a sieve winding spirally about said column; gatherboards or carriers beneath said
sieve; flights or blades applied to the upper surface of the sieve and serving to
loosen and to distribute material over its surface; and means for imparting to the
chest or casing a horizontal movement in a circular path.
8. In a sifting machine substantially such as described, the combination of a spirally
inclined sieve; a series of flights or blades projecting upward from the face thereof;
and means for imparting to the sieve a horizontal movement in a circular path.
9. In a sifting machine, the combination of a central trunk, a sieve winding
spirally about said trunk; and delivery chutes or spouts extending downward

page_text: within said trunk and having openings at different levels to deliver material upon
different portions of the sieve.
10. In a sifting machine, a sifting chest or body comprising an upper feed box a;
a lower discharge box b; an intermediate trunk c; a central pipe; and partitions
dividing the feed and discharge chambers and the trunk into compartments and
extending inward to the central pipe, substantially as shown.
11. In a sifting machine, a sieve support comprising an elevated feed box a; a
tubular trunk c extending downward from said feed box; a discharge box at the
lower end of the trunk; and partitions dividing the trunk and the boxes into
compartments.
12. The herein described sifting machine consisting of a frame A; a chest or
body B; hangers C carried at their upper ends by the frame and supporting the
chest at their lower ends; a feed box a at the upper end of the chest; a trunk c
extending downward from the feed box; a discharge box b at the lower end of the
trunk; partitions dividing the feed and discharge boxes and the trunk into com-
partments; a sieve winding spirally about the trunk; a casing or jacket enclosing
the sieve; inlet and exit openings through the walls of the trunk; stop boards
extending across the sieve below the exit openings; and means substantially such
as described for imparting a horizontal swinging motion to the chest B.
13. In a sifting machine, the combination of a central tubular column provided
with lateral openings; and two or more continuous spiral screens or sieves winding
about said column after the manner of a double screw thread and each arranged to
receive stock through the lateral openings of the central column.
14. In a sifting machine, the combination of a tubular central column provided
with lateral openings; two or more continuous spiral sieves or screens winding about
said column after the manner of a double screw thread; and gatherboards or
carriages similarly arranged, one beneath each sieve, the sieves being arranged to
receive stock through the lateral openings of the trunk.
15. In a sifting machine, the combination of a sieve in the form of a spiral
inclined plane; flights or blades rising from the surface of said sieve at
approximately right angles to the radii of the sieve; and meaus, substantially such
as described, for bodily moving the sieve horizontally, in a circular path, all
substantially as set forth.
16. In a sifting machine, the combination of a central column; arms extending
therefrom; sieve sections extending from arm to arm and supported thereby,
and flights or blades adjustably secured to said arms between the sieve sections,
substantially as described and shown.
17. In a sifting machine, the combination of a central support, a series of radial
arms; sieve frames or sections adapted to be inserted and removed into and from
the spaces between the arms; and flights or blades secured to said arms, whereby
the sieve sections may be withdrawn and replaced without disturbing said flights.
18. In a sifting machine, the combination of a spirally arranged sieve having a
continuous smooth upper face; and a series of flights or blades applied to said face
at intervals to distribute and shake or loosen the stock.
19. In a sifting machine, the combination of a central trunk containing feed and
delivery passages; a sieve winding spirally about said trunk; and a discharge box
at the lower end of the trunk and communicating therewith.
20. In a sifting machine of the character described, the combination of a central
column containing vertical passages; a gather box at the lower end of said column
divided into compartments and communicating with the passages of the trunk; a
sieve winding spirally about the trunk; and openings through the walls of the
trunk, whereby material may pass from the sieve into the trunk and thence to the
gather box.
21. In a sifting machine of the character described, the combination of a central
trunk or column containing upright passages; diaphragms extending across said
passages; feed openings formed through the walls of the trunk above, and discharge
openings formed through the walls of the trunk below said diaphragms; a gather

page_text: or discharge box at the foot of the trunk having compartments corresponding and
communicating with the passages of the trunk; and a sieve winding spirally about
the trunk, substantially as described and shown.
Dated this 4th day of May 1896.
WM. P. THOMPSON & Co.,
Agents.