Improvements in Machines for Separating Light from Heavy Substances.
Year: 1896

page_text: Date of Application, 2nd June, 1896-Accepted, 22nd Aug., 1896
COMPLETE SPECIFICATION.
Improvements in Machines for Separating Light from Heavy
Substances.
1, HEINRICH SECK, of No. 15 Leubuit zerstrasse, Dresden, in the Kingdom of
Saxony and Empire of Germany, 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 :-
This invention relates to machines for separating light from heavy substances,
and more especially to middlings purifiers for use in flour mills.
One object of the invention is to provide for an efficient separation of the
substances treated, such as grits or middlings, from the dust or other light particles
contained therein, while the said substances are caused to move over the surface of
the usual shaking sieve within the machine and there subjected in a well known
manner to the action of a current of air created by suction.
Other objects of the invention are, to provide for the possibility of continuously
observing and watching the process of separation from without, to admit of the
sifting surface being readily cleaned at any time, to prevent the accumulation,
within the machine, of the dust usually created therein by the suction current of
air and thus to keep the lateral glass windows of the machine clear, to dispense
with the deflectors usually employed in machines of this class and to provide for
a more efficient travelling movement of the material on the shaking sieve and hence
for a more efficient separation than has been possible to obtain heretofore.
The invention, therefore, consists in the details of construction and combination
of parts more fully hereinafter referred to and described, whereby the dust or
other light particles to be separated and removed from the material treated,
instead of being at once lifted and carried away in a vertical direction, are by
means of connecting suction canals or tubes sucked in a direction towards the
discharge end of the machine, this resulting in a speedier and more efficient
travelling movement of the dust or lighter particles relatively to the heavier
particles, such as the granules or grits or other material treated, at the same time
assisting the forward movement of the material worked upon and thereby preventing
all excessive accumulation of the said material on the sieve and thus reducing the
danger of the sifting surface becoming obstructed.
Another advantage obtained by the material on the sieve being thus moved
along by suction, is this that a current of air of less force than heretofore, is
required for separating out the light particles, experiments made having proven that
one of the connecting suction canals which are made relatively high in a vertical,
wide in the lateral and narrow in the longitudinal sense of the direction of the
path of movement of the sieve, has about the same useful effect as six of the open
spaces between the transverse channels or grooved bars heretofore employed
immediately above the sieve in machines such as the one described in prior
Patent No. 5155 of 1884; and still another advantage is this that, whilst the said
transverse grooves or channels debar from view the greater part of the sifting
surface, even when the lateral windows are opened, the improved construction
leaves the greater part of the sifting surface uncovered and thus visible from
without.

page_text: In the accompanying drawings illustrating the invention
Figure 1 is a vertical transverse section, on the line x-y Figure 2, of a sufficient
portion of a middlings purifier constructed according to my present invention to
render the improved construction thereof properly understood.
Figure 2 is a corresponding central vertical longitudinal section.
Figures 3, 4 and 5 are horizontal sectional plan views or diagrams showing
different modifications of construction and arrangement of the suction canals or
tubes, the latter being shown in Figure 3 as extending each diagonally across
the entire width of the sieve, whilst in Figures 4 and 5 they are shown as consisting
of tubes laterally interrupted by the separating bottom of the suction chamber and
arranged in transverse sets or rows.
Figures 6, 7 and 8 are transverse sectional views, taken on a similar sectional
line as that of Figure 1, and showing three modified constructions. According to
these modifications the suction canals or tubes are connected with the sieve frame.
In Figures 6 and 7 the collecting gutters are arranged within the sifting
chamber, whereas in Figure 8 they are located outside of the same.
Figures 9 and 10 are central vertical longitudinal sections or diagrams showing
different constructions of connecting suction canals or tubes.
Figures 11 and 12 are sectional details, taken on a similar sectional line as
Figure 2, of different modifications of construction and arrangement of the suction
canals or tubes more fully hereinafter referred to.
A designates the sifting chamber, that is to say, the space immediately above
the surface of the shaking sieve a, and B is the suction chamber. In the various
niodifications shown in the drawings different means are provided for effecting
an air-tight separation of the said sifting chamber from the suction chamber,
as will be presently described. The separating out of the light particles removed
by suction from the sifting chamber A, takes place within the suction chamber B,
au exhaust fan C acting within the latter.
According to my invention the means for sucking the light particles away from
the surface a within the sifting chamber and for conveying them into the suction
chamber, consist of a number of suction canals or tubes constructed and arranged
as bereinafter more fully described, the said canals or tubes terminating with their
lower ends in close proximity to the surface of the material travelling along the
sifting surface a within the sifting chamber A, whilst the upper ends of the said
canals or tubes extend into the suction chamber B.
In the construction shown in Figures 1 and 2 the suction canals or tubes, here
designated by b and c, enter the suction chamber B from below at certain portions
of the separating bottom thereof, said portions being formed in the manner of
pockets d. The lower ends of the said suction canals or tubes extending towards
the material to be treated, may terminate either in one or more sections, as shown
in connection with the canals or tubes and c, respectively; and their inlet
opening is preferably directed towards the feed end of the machine.
For this purpose the ends of the said suction canals or tubes may either be
bent accordingly or cut away on the respective side. The suction produced by
this means upon the material moving over the sifting surface in the direction of the
horizontal arrows (Figure 2) results in a certain acceleration of the travelling
movement of the material.
o
The suction canals or tubes b, c, as regards their sectional form and arrangement,
may each extend approximately across the entire width of the sieve whilst being
rather narrow lengthwise thereof, and they may extend either transversely to the
longitudinal axis of the sieve or diagonally thereto, as indicated in Figure 3. Or,
instead of each of the canals or tubes extending across the full width of the sieve,
they may form corresponding transverse or diagonal rows of two or more canals or
tubes of smaller section, and in this case they may be so arranged that the cauals
or tubes of the one row will alternate with those of the next row, as shown in 5
Figures 4 and 5.
In Figure 2 the canals or tubes are shown as being made adjustable vertically.

page_text: To this end the lower portion of each canal or tube is arranged to slide within, or
upon, the upper portion, so as to allow of being brought into the position e, as
indicated by dotted lines in Figure 2, when the sifting surface will be readily
accessible for cleaning.
The pockets d forming part of the separating bottom of the suction chamber B,
are in communication with gutters inclined transversely to the sieve. In the
construction illustrated by Figure 2, the said gutters are attached to the sieve
frame so as to partake in the shaking movement of the latter; they may, however,
if preferred, be attached to the framing of the machine. The pockets and gutters
are made air-tight and separated from the sifting chamber A by means of the
fabric g, so that the canals or tubes b, c form the only communication between the
sifting chamber A and the suction chamber B.
The operation of the devices described is as follows, that is to say: The suction
current of air passes through the material on the sieve from below and, there
lifting the dust and other light particles contained in the said material, carries the
same along upwards on its way through the suction canals or tubes b, c. By
reason of the reduced section of the said canals or tubes the air, in passing there-
through, has an additional pressure and, hence, a somewhat increased speed of
movement imparted to it. On arriving at the upper or discharge end of the said
canals or tubes the air current assumes a downward direction of movement and, in
spreading out freely within the pockets d and thence continuing on its way to the
exhaust fan, deposits the greater part of the light particles in the gutters, whence
the said particles thus separated out are, by reason of the inclined arrangement of
the said gutters or in consequence of the shaking movements of the latter,
discharged into the longitudinal gutters of the sieve. The discharge of the air
at the ends of the canals or tubes may be regulated by any suitable means, such
as the adjustable slide 7 shown in Figure 2, for guiding the air current during a
greater or smaller part of its course immediately after it has changed its direction
of movement.
In the arrangement above described the suction canals or tubes are supposed to
be secured to the framing of the machine, that is to say, to the air-tight bottom
of the suction chamber on its part rigidly connected with the said framing. They
may, however, if desired be connected with the shaking sieve frame, or in other
words, the separating bottom of the suction chamber provided with the said canals
or tubes, instead of being connected with the framing of the machine, may be rigid.
on the sieve frame so as to partake, with the canals or tubes passing therethrough
in the shaking movements of the said frame. Modifications of this kind are shown
in Figures 6, 7 and 8. In this arrangement a separating floor, such as i or i,
rigidly connected with the sieve frame, is provided at a suitable distance above the
sieve. An air-tight joint is formed between the sifting chamber A and the suction
chamber B by the fabric connecting the outer edges of the floor i (Figures 6
and 8) or (Figure 7) and the side walls u of the suction chamber above. The.
suction canals or tubes passing through the said floor deposit thereon the light
particles. The surface of the floor i is, in the construction shown in Figure 6,
inclined from the two sides to the centre, terminating at this point in a gutter k
which intersects the broad suction canals or tubes.
In some cases it is desirable to provide for keeping the material discharged from.
different sifting sections of the machine separated from each other, or to provide
for observing and testing the respective different portions of the material separately.
To this end a number of closed lateral canals m may in places branch off from the
central gutter k to the sides, the said lateral canals discharging the material
collected in the respective different sections of the machine into one or two longi-:
tudinal gutters n connected with the sieve. In Figure 6 these longitudinal gutters
are shown as arranged within the sifting chamber, the latter being closed at the
sides below by means of the fabric ".
In the modified construction shown in Figure 8 the said longitudinal gutters
are located on the outside of the sifting chamber, the latter being here similarly

page_text: separated from the suction chamber. This last described arrangement of the
longitudinal gutters presents the very important advantage that the material
discharged into the said gutters through the lateral canals m from the several
sections of the machine, may be observed and controlled and that it is thus rendered
possible to see at any time how the machine is working. In the arrangement as
heretofore, a window had to be opened when it was desired to gain access to the
longitudinal gutters, and every time when this was done while the machine was
in operation, the working of the machine would become temporarily impeded, and
moreover, even then the gutter was visible only to the extent of the length of the
opened window, whereas in the improved arrangement above described the gutter
is visible at all times in its entire length.
In the modification shown in Figure 7 the intermediate bottom, here designated
by the letter, instead of being inclined from the sides towards the centre, is
shaped in the manner of a roof and, instead of the central gutter k, two longi-
tudinal gutters k' are here provided into which the light particles deposited on the
bottom i, are discharged.
In Figures 9 and 10 the connecting canals or tubes 61 are shown as provided
with different kinds of outlets, the canals or tubes on the left hand side having
single outlets, whilst those on the right hand side have double outlets, so that the
air can escape on two sides. The regulation of the sucking current of air is
usually effected by suitable devices, such as valves provided in the top part of the
machine. These may, however, if desired, be arranged in the suction canals or
tubes themselves, as shown in Figure 10, where two of the said canals or tubes are
provided with valves o.
Figure 11 illustrates a modified arrangement which unites, as it were, the
principles of construction shown in Figures 1 and 2, on the one hand, and in
Figures 6, 7 and 8, on the other hand. The upper tube portion p of the suction
canal is here shown as being secured to the pocket d, whilst the lower tube portion g
is attached to the shaking sieve. The connection between the two portions is
formed by a tubular piece of flexible and air-tight material, such as canvas or
india-rubber, detachably held on one of the tube portions by a surrounding strap
or rubber band or other suitable means. With the other tube portion it may be
rigidly connected.
This construction possesses the advantage that it allows of making the sieve
comparatively light, which tends to make the machine run smoothly and easily.
The detachable arrangement of the lower tube portions permits of the entire
sifting surface being readily uncovered when it is desired to clean the same
thoroughly.
In Figure 12 the suction canal or tube c, secured to the pocket d in a similar
manner as in Figure 2, is provided on one side with a special suction openings the
size of which may be regulated by means of a slide t. This admits of creating in
the entire respective portion of the sifting chamber a slight upward air current
which will act to impart to the light particles of the material a tendency to remain
as much as possible near the surface of the material until the said particles, in
their forward movement over the sieve, will have come under the influence of the
suction canals, when they will be seized by the current and carried along upward
through the said suction canals or tubes, as already described.
It is obvious that the improved devices above described will require only a very
moderate current of air to enable them to serve the objects for which they are
intended. One reason for this is, that the suction canals or tubes approach very
closely the sifting surface, and another reason is, that the effect of the suction does
not extend over the entire area of the sieve, but is confined to certain portions
thereof and is materially increased by the narrow section of the canals or tubes in
which the air is thus caused to ascend with increased speed in consequence of the
pressure thereby imparted to it. As already stated, the said canals or tubes inay
either be cut away straight, as in case of the tube e shown in Figure 9, or
they may be cut away on a bevel, as shown in the other figures of the drawings.

page_text: The direction of movement imparted to the current of air by the latter construction,
possesses the advantage, that the lighter particles are not only lifted just at the
moment when they arrive below the canals or tubes, but that the said particles are
already previously brought under the influence of a lateral suction, as indicated in
the drawings by the arrow.
Since the entire quantity of air set in motion by the exhaust fan is obliged to
pass through the broad canals or tubes, it is obvious that no dust will be visible
immediately above the sieve in the sifting chamber which is hermetically separated
from the suction chamber. The glass windows will, in consequence not become
covered with dust and it will, therefore, at all times be possible to control the
progress of the material on the sieve through the closed glass windows. In the
improved construction described the greater part of the sifting surface remains
visible, since the suction canals or tubes are arranged at suitable distances apart,
which is to be considered an improvement on the arrangement described in the
patent already referred to, wherein a grate consisting of a number of transverse
grooves or channels overlies the sieve and excludes the greater part of the latter
froin view. Moreover, the fact that the inlet openings of the canals or tubes are
directed towards the feed end of the machine, results in an acceleration of the
travelling movement of the material on the sieve and, hence, in a more efficient
sifting action, as already stated. On the other hand, the arrangement of the
collecting gutters on the outside of the machine renders it possible to continuously
observe the operation of the machine without requiring the sifting chamber to be
opened for the purpose.
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. In a machine for separating light from heavy substances the combination of
an exhaust fan, a shaking sieve, a space hermetically separated from the latter
and adapted to receive the light substances conveyed thereinto by suction, and
the suction canals or tubes connecting the space above the shaking sieve with the
aforesaid space hermetically separated therefrom, substantially as and for the
purpose described.
2. In a machine for separating light from heavy substances the combination of
an exhaust fan, a shaking sieve, a space hermetically separated from the latter
and adapted to receive the light substances conveyed thereinto by suction,
means for collecting and removing the said substances, and the suction canals
or tubes connecting the space above the shaking sieve with the aforesaid
space hermetically separated therefrom substantially as and for the purpose
described.
3. In a machine for separating light from heavy substances the combination of
an exhaust fan, a shaking sieve, a space hermetically separated from the latter
and adapted to receive the light substances conveyed thereinto by suction, and
the suction canals or tubes connecting the space above the shaking sieve with the
aforesaid space hermetically separated therefrom, the said suction canals or tubes
having the openings at their lower ends directed towards the feed end of the
machine, substantially as and for the purpose described.
4. In a machine for separating light from heavy substances the combination of
an exhaust fan, a shaking sieve, a space hermetically separated from the latter
and adapted to receive the light substances conveyed thereinto by suction, means
for collecting and removing the said substances, and the suction canals or tubes
connecting the space above the shaking sieve with the aforesaid space hermetically
separated therefrom, the said suction canals or tubes having the openings at their
1wer ends directed towards the feed end of the machine, substantially as and for
the purpose described.
5. In a machine for separating light from heavy substances the combination of
an exhaust fan, a shaking sieve, a space hermetically separated from the latter

page_text: and adapted to receive the light substances conveyed thereinto by suction, means
for collecting and removing the said substances, and the suction canals or tubes
connecting the space above the shaking sieve with the aforesaid space hermetically
separated therefrom, and the conveying gutters arranged on the outside of the
machine, substantially as and for the purpose described.
6. In a machine for separating light from heavy substances the combination of
an exhaust fan, a shaking sieve, a space hermetically separated from the latter
and adapted to receive the light substances conveyed thereinto by suction, and the
suction canals or tubes connecting the space above the shaking sieve with the
aforesaid space hermetically separated therefrom, the said suction canals or tubes
having the openings at their lower ends directed towards the feed end of the
machine, and the conveying gutters being arranged on the outside of the machine,
substantially as and for the purpose described.
Dated this 2nd day of June 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.