Improvements in Machines for Separating Light and Heavy Substances chiefly Designed for the Purification of Grits and Middlings.
Year: 1884

page_text: 3
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Improvements in Machines for Separating Light and Heavy
Substances chiefly Designed for the Purification of Grits
and Middlings.
COMPLETE SPECIFICATION.
"
I WILLIAM ROBERT LAKE of the Firm of Haseltine Lake & Co Patent Agents
Southampton Buildings London in the County of Middlesex do hereby declare the
nature of said Invention for IMPROVEMENTS IN MACHINES FOR SEPARATING
LIGHT AND HEAVY SUBSTANCES CHIEFLY DESIGNED FOR THE PURIFICATION OF
GRITS AND MIDDLINGS" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :—
W
This Invention relates to apparatus for separating by means of air-suction, light
and heavy substances, and is more particularly intended for the purification of grits
and middlings in the manufacture of flour-with a view to obviate the danger of
fire and explosion arising from the deposition of the dust from the said middlings
and, heretofore, generally collected in separate dust collectors, or dust-chambers.
The said Invention consists partly in the novel arrangement of a continually
travelling endless filtering-cloth directly over the substances to be separated while
they are moved along on a rocking sieve, the said arrangement dispensing with the
employment of intermediate apparatus underneath the said filtering cloth and
above the said sieve and having for its object to divide the suction of air uniformly
across the entire area, or surface, of the substances to be separated, so that the
latter are acted upon at every point of their surface whereby a uniform separation,
or purification is obtained.
It also partly consists in constructing the said rocking sieve combined with the
filtering-cloth arranged as above stated, with a grate formed by a series of parallel
inclined grooves or channels, in order to cause an intense sucking action between
the openings of the said grate, to prevent the heavier portions of the light
substances carried up towards the filtering-cloth by the flow of air, from falling
back upon the mass of heavy substances on the rocking-sieve and to provide means.
or separately collecting the said heavier portions of the light substances which
are not retained by the filtering cloth, or which drop back before reaching the
atter,

page_text: It also partly consists in a novel and simple manner
interposed plate arranged within the interior of the said filtering cloth, a space or
chamber within the said cloth which is not acted upon by the air, and in the
combination, with the said space or chamber, of a continuously operating beating
devico consisting of a number of elastic beating-rods suitably connected either with 5
a rotating or with a rocking shaft.
It also partly consists in novel means for tightening and stretching the travelling
endless filtering-cloth, and in the combination with the latter, of a conduit for
continuously returning the air passing through the said cloth, and causing it to
enter below the rocking sieve carrying the substances to be separated.
In the accompanying Drawings forming part of this Specification
Figure 1 is a longitudinal vertical section of a machine constructed according to
this Invention.
Figure 2 is a transverse section of the same.
Figure 8 is an end view of the samo.
=
Figures 1 and 2 show part of the rocking-sieve constructed with the said grate
drawn to an enlarged scale.
Figures 4 and 5 show the device for beating the filtering cloth.
Figures 6, 7 and 8 illustrate-the means for tightening and stretching the said
cloth, and
Figures 9, 10 and 11 show a modification of the said means.
All the views of details above mentioned are drawn to enlarged scales.
A indicates the frame of the machine having the upper end-plates a a¹ in which
are suitably journalled the four rollers b¹, b³, b³, 64 arranged longitudinally of the
frame. Bindicates the endless filtering cloth passing over the said four rollers and
moving transversely of the machine when rotatory motion is imparted to the
rollers. Upon each end of each of the four rollers is secured a sprocket-wheel c.
The four sprocket wheels on each end of the machine are connected by an endless
chain c³ the several links of which are firmly connected, by means of suitable hooks
or staples, with the filtering cloth B, so that the latter will be stretched in the
direction of its length and partake of the motion of the chains c' when the latter
run over the several sprocket wheels c.
1
a² a² indicate wooden bars of convenient shape which are arranged above the
flanges of the end plates a a' and held in position thereon by means of suitable
connecting-plates a secured to the end plates a a' and bars a³ by bolts or screws,
the said bars a² serving to hold the filtering-cloth in contact with the flanges of the
end-plates a, a¹ so as to prevent the outside air from entering the interior of the
machine. As shewn in Figures 6. 7 and 8 the said connecting-plates a' have an
angular form in order to allow the chain c¹ to pass between them and the plates a a';
but in cases where the chain is dispensed with as a means for imparting motion to
the filtering-cloth, the plates a* may be of the plain form shown in Figures 9, 10
and 11, In the modified arrangement illustrated in the latter Figures, the
tightening and stretching of the filtering cloth is provided for, as follows:-
The rollers b&. near each of their ends, are provided with circular grooves or
channels o³, and between the said rollers the end-plates a, a¹ of the frame are
constructed with flanges d³ projecting inwardly and having the grooves c³. A strip
of leather or other suitable material is fastened by stitching to the underside of
the outer rims of the filtering-cloth B, and a similar strip of linen enclosing a
rope d' is stitched to the underside of the leather. The rope d' is inserted into the
said grooves c² and c³ and is held in position therein by means of the bar a³ fastened
upon the end plate a by the connecting-plate a*, thus holding the filtering-cloth
longitudinally in a stretched position, while at the same time, the connection
between the end-plate and the filtering cloth is tightened effectually so that air
cannot enter the interior of the machine from without.
Of the end-plates a a', the the plate a is closed, while the other a¹ is provided
ith a suitable onening which is connected to the conduit C of the ventilators C
10
1
2

page_text: so as to allow the latter to suck the air from the interior of the filtering cloth B
through the said end-plate a¹.
D indicates a plate, or board, secured to the inner sides of the end-plates a a¹
and bearing with the least friction possible against the two rollers b¹ be of the said
rollers b, but at the same time tightening well upon the said rollers b¹ and 6* so as
to divide the interior of the filtering-cloth B into two spaces or compartments, that
is to say, into a space e which is acted upon by the flow of air caused by the
sucking-action of the ventilators, and into a space which is not disturbed by the
said sucking-action and the flow of air thereby produced.
Another plate or board D¹ is arranged above the filtering-cloth B and secured, in
a similar manner to the board D, to the end-plates a, a¹ the said plate D¹ also
bearing with little friction, but with a tightening effect, against the outside surface
of the filtering-cloth B passing over the roller b³, and against the head-plate A³ of
the machine in order to exclude the air suction from the space, or compartment, e¹,
on the left-hand side of the machine. This space e' is prevented from being acted
upon by the said air-suction, by the extension-plate or board g¹ of the trough g of
the conveyor g³ bearing tightly against the left-hand side-plate A¹ of the machine,
and by the upper right hand flange of the said trough g bearing with a
tightening effect against the outer surface of the filtering-cloth passing over the
lower roller b¹.
Arranged in the said space c' excluded as described from the air-suction prevailing
in the other portion of the machine, is a shaft h which is suitably journalled in the
end plates a, al and provided with five or any other convenient number of cams '
the said cams being arranged rectangularly upon the shaft h, but pointing in
different positions with relation to each other, as will best be seen from Figuro 4 of
the Drawings.
L
ii indicate elastic benters of stoel or other suitable metal corresponding in
number with the cams 'upon the shaft h, the said beaters being secured to the
side-plate A' of the frame A by means of draw-springs attached to their
upper ends.
indicate plates pivotted to the side-plate A¹, and secured, near their outer
ends, to the beaters i so as to project beyond the latter and form shoulders i³
against which the respective cams h¹ will strike when the shaft h is rotated in the
direction of the arrow. The lower end of each beater is provided with an eye for
the reception of a beating rod, i, composed of elastic wood, or metal.
E indicates the rocking-sieve arranged in an inclined position in the usual
manner, and constructed with a grating consisting of a series of parallel bars, or
plates j, of wood, metal, or other suitable material having inclined grooves, or
channels, more particularly shown in Figures 1 and 2 of the drawings, the said
grooved bars or plates, j being arranged immediately above the sifting surface and
partaking in the rocking movement of the rocking-sieve E of which they form a
part. The said rocking-sieve E, no matter whether it be constructed with the said
grating or without the same, is arranged immediately below the lower suction
surface of the filtering-cloth B, so that all intermediate apparatus between the
cloth B and the rocking-sieve E is avoided. The grooved bars ; may be so
arranged that their channels will run either in a transverse, or in a longitudinal
direction upon the rocking sieve E, the former arrangement being illustrated in the
drawings. The lower ends of all the grooves in the bars ; deliver into a
conveyor J which is arranged near one side of the machine but would have to be
placed near one of the ends of the latter if the longitudinal arrangement were
to he chosen for the grooved bars ; of the rocking-sieve E. The required
reciprocating motion is imparted to the latter in a well known manner by means
of the eccentric E'.
E indicates a hopper for the reception of the substances to be separated upon
the sieve E, and E³ is a brush applied to an endless band, intended to cleanse the
lower surface of the said sieve, but forming no part of my Invention.

page_text: Arranged below the rocking-sieve E are two conveyors E E³ which serve for
educting from the machine the purified heavy substances passed through the
sifting surface of the rocking sieve E. Either of the conveyors E E³ may be
covered entirely or partly by means of the hinged lids so as to allow of
educting either the whole of the purified substances by one conveyor only, or one
part of the said substances by the one, and another part by the other conveyor.
CC indicate air chambers, or return-conduits, connected with the ventilators
CC and provided for the purpose of continuously returning the air exhausted by
the said ventilators through the conduit C, into the machine below the rocking-
sieve E. The walls of the conduits C' are provided with the valves for regulating
the entrance of air into the portion of the machine under the rocking sieve E, and
plates are arranged obliquely behind the valves so as to cause the air returned
through the latter to break its force by striking against the said plates, and thus to
become quieted in order not to disturb or agitate the mass of substances upon the
rocking sieve.
indicate valves, or shutters, which may be opened in cases where it is desired
to introduce fresh outside air into the machine.
Motion is imparted to the several working parts of the machine, as follows, that
is to say-The main driving shaft 1 provided with the eccentric E¹ for
reciprocating the rocking-sieve E, is rotated by means of a pulley driven by any
suitable motor, and, through belts running over the pulleys 12 and 13 secured
upon the shafts 2 and 3, imparts rotary notion to the latter, the former of which
carries the fans of the ventilators C¹, while the other shaft 3 is provided with
suitable bevel gear wheels for revolving the shafts 4 and 5 of the conveyors E
and E³, and with a pulley and, belt for revolving the shaft 6. From the latter,
motion is imparted to the endless band carrying the brushes E3 and through the
said band, to the shaft 7 which, by means of a belt, will rotate the shaft 8 of the
feeding-roller arranged below the lower end of the hopper E². The conveyor J
and its shaft 9 are rotated by the shaft 4 by means of a belt and pulley, and this
rotation is transferred to the roller b', by means of the chain 14 and the sprocket-
wheels 15 and 16. The rotation of the roller b₁ will cause the sprocket-wheels c,
secured thereto at both ends, to rotate likewise and, by means of the endless
chain c¹, to transmit this rotatory motion to the other sprocket-wheels c secured
upon each end of the rollers 6, b, b, which will cause the latter to revolve in duc
relation to the speed of the filtering cloth B moved by the chain c', to the links of
which it is secured. The roller 6¹ is provided with an extension upon which is
secured the star wheel 20 in gear with a similar pinion 21 applied to the shaft 10
of the conveyor g² the latter being thus revolved. A sprocket-wheel 18 is secured
upon an extension of the roller b³, and is connected, by means of an endless
chain 19, with a similar sprocket wheel 17 upon the end of the shaft of the
beating-device, so that when the said roller b² is rotated, rotatory motion will also
be imparted to the shaft h.
The operation of the improved machine for separating light and heavy substances
by means of air-suction is as follows, that is to say :-
The substances to be separated fall upon the sifting surface of the rocking-
sieve E from the hopper E, and are moved forward on tho said sieve by reason of
its rocking movement which causes the heavy portions of the substances to go to
the bottom and to drop through the sifting surface into the conveyor E* or E
below. At the same time, the ventilators C¹ will draw the air through the ältering
surface of the filtering cloth B arranged immediately above the rocking-sieve E,
the flow of air thus produced acting quite uniformly upon every point of the
substances to be separated so as to draw off the lighter portions of the same and
carry them upward towards the surface of the filtering-cloth B It is well know
that in purifying heavy substances, such as middlings for instance, the air suction
if properly regulated, does not possess sufficient power to carry the heavier portions

page_text: of the light substances drawn off the rocking-sieve sufficiently high to bring or hold
them in contact with the filtering cloth.
According to my Invention the said heavier portions of the light substances are
prevented from falling back upon the rocking-sieve and the substances thereon, by
the peculiar construction of the said sieve which has the grating formed of the
grooved bars j and which allows the air to act with uniform suction upon every
point of the substances to be separated, or purified, and causes a high tension, or
compression of the air current through the longitudinal openings between the
bars so that the light substances which are dropped by the air, before they reach
the filtering-cloth B, will be prevented by the currents of compressed air rising
between the bars j, from falling between the said bars upon the mass of henvy
substances below, but will be driven sideways by the said compressed currents and
thus caused to drop into the grooves, or channels, j, above which the air-currents
are of a comparatively reduced intensity. The heavier portions of the light.
substances which are thus dropped into the channels are delivered into the
conveyor J, by reason of the rocking movement of the rocking sieve, and educted
from the machine by said conveyor into some suitable receptacle.
The light substances carried upward against the filtering-cloth B, will adhere to
and be carried on by the latter in the direction of the arrows Figure 2 until they
enter the space e' which, as above stated, is not acted upon by the air-suction. On
entering this space e', and while passing through the same, they are beaten off the
filtering cloth B by means of the beating-device composed of the beaters i and the
beating rods as follows:-The cam-shaft h is rotated by the roller b and the
endless connecting chain 19, as described, in the direction of the arrow, Figure 4,
which rotation causes the cams h¹ to strike alternately against the shoulders i³ on
the pivotted plates of each of the beaters i, so that the latter will be pressed
away from the surface of the revolving filtering cloth B. This movement of the
beaters i will expand the draw springs attached to their upper ends. As the
shoulders are released by the cams h¹ in quick and regular succession, the
springs will alternately draw back the upper ends of the beaters i and throw
their lower ends provided with the transverse beating-rods *, with a sudden
elastic blow against that portion of the filtering-cloth B moving before the space f
which as above stated, is excluded by the board D from the action of the sucking
air. The elastic blows thus successively applied to the said portion of the moving
filtering cloth, cause the light substances adhering to the latter, to fall off and drop
into the conveyor g³. By reason of the arrangement in different positions of the
cams upon the shaft h, the beaters are pressed away successively from the
cloth B, and strike against the same one after the other, so that the several elastic
beating-rods will strike in regular alternation against the surface to be beaten,
without thereby disturbing the sucking surfaces of the filtering cloth. The light
substances beaten off, are conducted, by the conveyor g³, into some suitable receptacle.
It will thus be seen from the above description that with the construction of the
machine as herein described, the heavy substances passed through the rocking-
sieve E, will be conveyed away by the conveyors E E³, the heavier portion of the
light substances by the conveyor J, and the light substances by the conveyor g² so
that they may be collected in separate receptacles.
The beating device may be modified so that the beaters i are rigidly secured to
the shaft h. With this modification a rocking motion would have to be imparted
to the said shaft by means of some suitable cam and eccentric, which would cause
the beating-rods to strike simultaneously, instead of alternately, against the
enclosed portion of the filtering-cloth B, but such arrangement would not be as
preferable as the one herein before described, for the reason that the filtering surfaces
of the cloth, B would be more likely to be disturbed by the combined, than by the
alternate blows of the rods *.
In some cases, and more particularly where the machine is used for purifying
very light substances from dust and the like, I may construct the rocking-sieve E
•

page_text: without the grooved bars ; and regulate the flow of air so that the dust and similar
matter only are sucked off the mass of substances on the rocking-sieve.
The air which is sucked through the filtering cloth B by the ventilators C¹, is
continually returned by the return conduits C into the machine below the rocking
sieve E, the object of this arrangement being to avoid the necessity of drawing 5
fresh air into the machine from without. Drawing in air from without the machine
causes an unpleasant agitation of the air and a reduction of the temperature of the
latter outside the machine, but this difficulty is obviated by the combination of the
ventilators C' with the return conduits C which allow of dispensing with the
introduction of outside air in the machine, since as no air can escape from 1
the machine the same air is used over and over again for the purification of the
substances, as will be readily understood.
But in 1
I am aware of the fact that in a former machine for filtering grains and other
substances by means of air suction, an endless filtering cloth has been proposed, and,
therefore, I make no claim for a revolving endless filtering cloth per se.
the former instance referred to, the filtering cloth was arranged so as to move in a
longitudinal, instead of transverse, direction of the machine, and was not apt to
give good results in practical use, partly for the reason of the said longitudinal
arrangement of the filtering cloth, and partly because of the difficulty in
constructing the space not acted upon by the air suction but chiefly for the reason
that intermediate apparatus was provided between the surface of the filtering cloth
and the rocking-sieve which would prevent the said surface, arranged at a
comparatively great distance above the rocking-sieve, from acting uniformly upon
the entire surface of the substances to be purified, so that, at some points, part of
the heavy substances would be carried off by the air-suction, while, at other points
again, the light substances would not be sucked off at all, and remain among the
I obviate these difficulties with my
heavy substances after the purification.
improved machine as herein-described, by arranging the lower surface of the
filtering-cloth immediately above the upper surface of the rocking-sieve, and by
moving the endless cloth in the transverse direction of the machine and providing
for the space not acted upon by the air-suction, in a simple and, at the same, time
most effective manner.
I wish it to be understood that I do not confine myself to employing four
rollers b for guiding the filtering-cloth B, as it will be seen that any suitable
number of such rollers may be used for this purpose, and also that the roller b³ may
be dispensed with and the filtering cloth conducted directly over the rollers &¹
and be from the roller b, if desired.
my said
Having now particularly described and ascertained the nature of
Invention and in what manner the same is to be performed I declare that I claim
in a machine for separating light and heavy substances by means of air suction:
First. The combination with a rocking-sieve, of a travelling endless filtering-
cloth arranged immediately above the said rocking-sieve, substantially as, and for
the purpose, specified.
Second. The combination with two adjacent rollers b, of the plate D, substantially
as, and for the purpose, specified.
Third. An endless filtering-cloth B moving transversely of the machine,
substantially as, and for the purpose, specified.
Fourth. The combination with a travelling endless filtering-cloth, of the elastic
beaters having the transverse beating-rods i, substantially as, and for the
purpose, specified.
Fifth. The combination of a travelling endless filtering cloth, with the chains c
of the sprocket-wheels c, substantially as, and for the purpose, specified.
Sixth. The combination of the travelling endless filtering cloth B having th
rope d, with the rollers 6 having the grooves c², substantially as; and for th
purpose, specified.

page_text: Seventh. The rocking-sieve E having the inclined grooves j, substantially as, and
for the purpose, specified.
Eighth. The combination with the travelling endless filtering cloth, of a conduit
for returning the air sucked through the said filtering-cloth into the lower part of
the machine below the rocking sieve, substantially as, and for the purpose,
specified.
Dead ! 106 •