Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates to a process and apparatus for
recovering tobacco particles from packaged cigarettes.
Packaged cigarettes have a limited storage life, after which the
cigarettes are usually considered by the manufacturer to be
unsaleable. The tobacco combined in the cigarettes, if
reclaimed, can, however, be treated, e.g. re-humidified, to
render it re-useable in cigarette production. There are,
however, considerable difficulties in recovering the valuable
tobacco from the packaged cigarettes. There are various
machines known ~or recovery of tobacco ~rom loose cigarettes.
Utilization of these machines for tobacco recovery from intact
packages would, however, require that the packaqes first be
opened and the cigarettes removed from the packages, and, in the
present state of the art, this operation can be conducted
satisfactorily only by hand, and the expense of this makes the
procedure uneconomical.
There have been prior attempts at processing of intact packages
in order to liberate the tobacco particles, but there is the
difficulty that procedures for automatic ripping open of the
packages tend to produce fine fibres and other particles of
paper, cellulose film and other non-tobacco materials from the
cigarette paper tubes, filters and packaging materials. These
fine particles are of size substantially the same as or smaller
than the tobacco particles. This makes it difficult or
impossible to separate the fine non-tobacco particles from the
tobacco particles to achieve tobacco of quality adequate for
re-use in cigarette manufacture, since there is insufficient
difference in density between the paper and other non-tobacco
particles on the one hand and the tobacco particles on the
other. Before the present invention, therefore, it has been the
common practice to destroy the unsaleable packaged cigarettes by
burning them or burying them in disposal sites.
The present inventors have found~ surprisingly, that intact
cigarette packages can be readily disintegrated to form a
disintegrated mixture of tobacco particles with paper or other
- 1 ~r~
non-tobacco fragments which are substantially larger than the
tobacco particles, and which can, therefore, be readily separated
from the former, using, for example, a modified form of threshing
machine of the type conventionally employed for threshing tobacco
lea~, in tobacco processing.
In the method of the invention, the intact packages are subjected
to a disintegrating action effected between impeller members and
one or more pairs of longitudinally~extending rows of teeth, of
which the teeth in each row pro~ect transversely toward the teeth
in the adjacent row. Each impeller member has its cross-section
elongated in the longitudinal direction, and is moved generally
longitudinally relative to the rows. The intact packages are fed
to the teeth, and are drawn along the teeth by the impeller mem-
bers and are thereby disintegrated. It has been ~ound that, with
this arrangement, it is possible to tear the packages and the
paper tubes of the cigarettes contained in the packages into non-
tobacco fragments which are substantially larger than the tobacco
particles contained in the cigarettes. The resulting mixture of
non-tobacco fragments and tobacco particles can then be subjected
to particle separation procedures effective to separate out
tobacco particles substantially free of non-tobacco fragments.
In the preferred form, the process is conducted using a modified
tobacco threshing machine, in which the teeth are defined by cir-
cumferentially extending slots formed in a stationary semi
cylindrical shell, known in the art as a basket, and the impeller
members are blade-like members mounted on a rotor which rotates
about an axis coincident with that o~ the basket. It will,
however, be appreciated that the above-described disintegrating
function can be effected, although with less advantage~ employing
equivalent arrangements such as, for example arrangements wherein
a slotted planar plate or other planar member defining teeth is
employed, and the impeller members are swept over the surface of
the planar plate or member by, for example, an endless belt to
which impeller members are attached, and which is disposed
parallel to the planar member. Similarly, in other arrangements,
the impeller members may be stationary, and the array of teeth
-- 2 --
may be moved relative to the impeller members, e.g. they may be
rotated about the impeller members.
One advantage of the present method is that it can be conducted
using a modified form of a machine, i.e. a threshing machine,
normally employed in the tobacco processors plant.
In the preferred form of apparatus according to the present
invention, the teeth are ~ormed in a relatively thin shell, and
are defined by a series of elongated indented slots of approxi-
mately constant width extending in a longitudinal direction. The
ratio of the width of these slots to the smallest dimension of
the rectangular packages is preferably in the range about 20:1 to
1:1. The impeller members employed for moving the packages rela-
tive to the teeth are preferably spaced apart uniformly trans-
versely at a distance about 0.8 to about 3 times the width of the
slots. The present inventors have found that, where the width of
the slots between the teeth or the spacing between the impeller
members is made substantially less than the ratios indicated
above, the disintegration operation tends to produce undesired
small paper fibres unless the speed of the impeller members rela-
tive to the teeth is considerably reduced, thus slowing down therate of disintegration and hence the rate of throughput of the
packages. If the width of the slots between the teeth or the
transverse spacing between the impeller members is made much
greater, the efficiency of the disintegrating action tends to be
impaired, as intact packages tend to build up within the disin-
tegrating apparatus, resulting in a reduction in the throughput
of packages, or an undesirably large proportion of packages may
tend to pass intact through the disintegrator apparatus. In the
preferred form, the width of the slots between the teeth is in a
ratio of about 10:1 to about 2:1 to the smallest dimension of the
intact packages which are to be disintegrated, and the spacing
between the impeller members is about 1 to a~out 17 5 times the
width of the above-mentioned slots.
Further preferred features and advantages of the present process
and apparatus will become apparent from the following detailed
~.g~
description, taken in association with the accompanying drawings,
wherein:
Figure 1 is a plan view of a preferred form of apparatus in
accordance witn the invention;
Figure 2 is a side elevation taken on the line 2-2 in Figure 1;
Figure 3 is a partially fragmentary end view of the preferred
form of modified threshing machine employed in the present
apparatus;
Figure 4 is a partially fragmentary front elevation of the basket
and rotor of the threshing machine of Figure 3;
Figure 5 is a side view, partially in section taken on the line
5-5 in Figure ~;
Figure 6 is a side view of a solids-air separator device employed
in the present apparatus;
Figure 7 is an end elevational view, taken on the line 7-7 in
Figure 1; and
~igure 8 is a front elevational view, taken on the line 8-8 in
Figure 1.
Referring to the drawings~ the apparatus comprises an endless
belt feed conveyor 11, of which the upper flight, travelling in
the direction of the arrow 12 in Figure 1 inclines upwardly from
a feed hopper 13 to an inlet hopper 14 of a modified form of
tobacco threshing machine 16.
As shown in more detail in Figure 3, the machine 16 comprises an
upper casing 17 having an upper inlet opening 18 into which the
hopper 14 feeds. Referring to Figures 4 and 5, within the casing
16 is supported a semi-cylindrical basket 19, which is in the
form of a thin semi-cy].indrical shell apertured by generally
~2~8~
longit~dinally-extending slots 21. These slots 21 are of
indented configuration, and are of approximately constant width
"W" as indicated in Figure 4, and thus de~ine between them sets
of triangular teeth 22 disposed in longitudinally-extending rows
in pairs, one on each side of a slot 21. The teeth 22 in each
row project transversely toward the teeth in the adjacent row,
and each tooth lies in the yeneral surface of the semi-
cylindrical shell or basket 19, and is offset longitudinally
relative to the teeth in the adjacent row. Each tooth tapers
toward a pointed end facing to~ard the teeth of the opposing
row. As will be seen from Figures 4 and 5, each tooth 22 is
relatively thin compared with its length, since the thickness "T"
(as shown in Figure 5~ of the shell 19 is small relative to the
length "L" (as shown in Figure 4) of each tooth 22. The ratio
T:L is desirably in the range from about 0.01:1 to about 0.2:1,
more preferably about 0.05:1 to 0.15:1. Thus, the side edges of
the teeth present relatively thin elongated surfaces well adapted
for severing and tearing the cardboard and paper and other
wrapping and packaging materials of the intact cigarette
packages, as ~ell as the paper of the cigarette tubes themselves.
Also within the casing is mounted a rotor 23 having an axle 24
journalled within the upper casing 17, on an axis coincident with
the axis o the shell 19. A drive for rotating the rotor 23 at
controlled speed is connected to the axle 24. The rotor 23
consists of a series of circular disks 26 keyed on the shaEt 24,
and having spacers 27 arranged between them. A series of rods 28
are passed axially through apertures in each disk 26 and the
spacers 27. The rods 28 are threaded at each end, and have nuts
29 secured to them, thus clamping the disks 26 and the spacers 27
together firmly. A series of blade-like impeller members 31 are
mounted on the rotor 23, and are distributed substantially
uniformly circumferentially and axially on the rotor. In the
example shown, the impeller members 31 are disposed in six rows,
with the rows being positioned at uniform angular spacings around
the axis of the rotor. Desirably, each impeller member 31 is
spaced axially from its adjacent impeller members in the row by a
distance D, as shown in Figure 4~ which is about 0.8 to about 3
~2~
times, more preferably about 1 to about 1.5 times the width W of
the slots 21 between the teeth 22 of the basket 19, in order to
exert an efficient disintegrating action on the cigarette packets
fed into the basket 19, without production of excessive quanti-
ties of small paper fibres or other non-tobacco fibres of small
size the same as or substantially the same as the size of the
tobacco particles. Desirably, hardened, e.g. carbide, inserts 32
are welded in leading edges of the impeller members 31 at their
tips, to reduce wear.
1~ Desirably, the width W of the slots 21 is in a ratio of about
20:1 to about 1:1 to the smallest dimension, for example the
thickness, of the packages which are to be disintegra~ed. More
preferably, this ratio is about 10:1 to about 2:1. Further, in
order to efficiently disintegrate the packages without excessive
production of fine paper fibres, it is desirable to control the
speed of the impeller members 31 relative ~o the teeth 22.
Desirably, the tips of the impeller members 31 move at a speed of
about 1500 to 5000 ft./min. relative to the teeth 22, more
preferably about 2000 to about 4000 ft./min., and still more
preferably about 2500 to about 3500 ft./min., relative to said
teeth.
Merely by way of example, it may be mentioned that the
semi-cylindrical shell 19 may have a radius of about 1 ft. 1 and
5/8 inches, and a length of about 2 ft. 6 inches. The width W of
the channels between adjacent teeth may be approxima~ely 2
inches, and each tooth may have a length L of about 2 and 1/2
inches. The thickness T of the thin shell 19 may be about 7/32
of an inch.
The rotor 23 as shown may comprise disks 26 of about 16 inch
diameter, and each plate-like impeller member 31 may project
radially a distance about 4 and 15/16 inch beyond the edge of
each disk 26. The spacing D between adjacent impeller members 31
may be about 2 and 1/2 inches, which may be arrived at by
modifying a conventional tobacco thresher rotor by removing every
other impeller member 31, so that the spacing between adjacent
~.:2Q~
impeller members is doubled as compared with the spacing in the
conventional threshing operation, except adjacent the ends of the
rotors, where some impeller members, e.g. the impeller members
31a may be left at their usual spacing, in order to avoid
excessively large gaps between impeller members and the adjacent
ends of the rotor. with the rotor and basket having the above
dimensions, particularly satisfactory disintegration action is
achieved in use, without excessive production of small paper
fibres or other small non-tobacco particles, when the rotor 23 is
rotated in the direction shown in Figure 3 at about 450 rpm, so
that the tips of the impeller members 31 travel at a speed of
about 3000 ft./min. relative to tne surroundings
The above described machine is also modified as compared with the
conventional tobacco threshing arrangement in that a row of
stationary blade-like members connected to and projecting
inwardly from the inner wall of the casing 17, somewhat in the
manner of a comb down through which the impeller members 31 of
the rotor normally pass as the cylinder rotates, is removed, so
that, in the upper portion of the casing 17, the impeller members
31 rotate through free space. It has been found that removal of
these stationary blade like members further reduces the tendency
toward production of fine non-tobacco particles. Merely by way
of example, it may be mentioned that the threshing machine 16 may
be a modified Cardwell (trade mar~.) Thresher Model MT450.
Connected to the bottom of the casing 17 of the machine 16 is a
hopper 34, which receives disintegrated material passing through
the basket 19. The lower end of the hopper 34 opens into an
intermediate portion o~ a horizontal run of a duct 36. This
connects through an elbow to a vertical portion 37 of the duct,
and through a further elbow to a raised horizontal portion 38,
which feeds to ~he inlet of a tangential separator 39, shown in
more detail in Figure 6.
The tangential separator 39 comprises a generally cylindrical
casing, having its axis horizontal, and with a rectangular inlet
41 leading ~o a throat 42 disposed tangentially of the
~2~
cylindrical curvature of the device. The separator has opposing
side walls 43 and 44 curving downwardly toward a tapering lower
outlet 46 which opens into an air lock device comprising a
cylindrical casing 47 having its axis parallel to that of the
separator 39. The separator 39 has on one side a relatively
large central opening 48 adjacent which extends, across the width
of the separator, a curved inner baffle 49 on the same side of
the opening 48 as the inlet opening 41l and somewhat below the
central opening 48. The separator functions somewhat in the
manner of a cyclone, and, through its geometry, is effective to
cause solids entrained in the airstream entering through the
throat 42 to travel tangentially around the circumference of the
separator and to accumulate at the lower outlet throat 46, while
the air or gas phase tends to flow outwardly through the axial
opening 48.
The casing 47 of the air lock device has an opening in its lower
surface, which communicates with a tapering outle~ 51 at the
lower end of the device. Mounted within the casing 47 is a
paddle-wheel-like arranyement 52 rotated through a drive 53 from
a motor 54. The tips of the paddles 42 have flexible sealing
members ~6 which scrape the inner surface of the casing 47, and
thus form substantiall~ sealed compartments between each paddle
52 and the interior surface of the casing 47. Thus, solids
falling into the casing 47 through the throat 46 are conveyed by
the rotation of the paddle-wheel arrangement arcuately downwardly
to the outlet 51, while escape of any major flow of air from the
inside of the device 39 is prevented. ~erely by way of example,
the separator 39 may be a Cardwell Tangential Separator Size
36-60.
As shown in Figure ~, a fan 57 is mounted coaxially of the
separator 39, and exhausts air through the central opening 48 and
blows it through a duct 58 sloping downwardly through a portion
59 to elbows 60 and 61, seen in Figures 1 and 2, leading to the
duct portion 36 connecting to the lower end of the machine 16, so
that air flows in a substantially closed loop between the machine
16 and the separator 39O
-- 8
The outlet 51 o~ the air lock casing 47 connects to the upper
portion of one side of a pneumatic lift device 62, which
comprises a rectangular chamber 63. On the side to which the
outlet 51 is connected, the pneumatic lift device 62 is formed
internally with a vertically-extending chute, at the lower end of
which is arranged a driven paddle-wheel device 64, so that solids
falling down the chute are cast laterally by the device 64 across
the interior of the chamber 63, along paths indicated by broken
lines 66 in Figure 2.
An inclined wire mesh screen 67 extends transversely across the
interior of the lift device 62, and extends outwardly and down-
wardly through an opening 68 at the lower side. Air is drawn
upwardly out of the upper end of the lift device 62 through a
duct 6g passing to a tangential separator 71 similar to the
separator 39. The axial exhaust from the tangential separator
71, passing through a duct 72, is blown by a fan 73 along duct
portions 74, 76, and 77 to an elbow leading to a vertical duct
section 78 passing through an elbow to an inlet duct 79 which
feeds into the bottom of the lift device 62. Thus, air is passed
upwardly through the chamber 63 of the device 62 and through the
tangential separator 71 in a substantially closed loop.
The air passing upwardly through the lift device 62 passes
through the inclined screen 67, and its upward velocity is con-
trolled so that heavier components present in the material cast
laterally through the casing 63 by the paddle-wheel arrangement
64 are not entrained by the airstream, but fall onto the inclined
screen 67. The inclined screen 67 is connected to a vibrator or
shaker device, and the vibrations cause such components falling
on the screen to travel gradually ~own the incline of the screen
67 toward its lower end. The pneumatic lift device 62 may be,
for example, a conventional form of pneumatic lift and separator
device employed in tobacco threshing. Merely by way o~ example,
the pneumatic lift device may be a Cardwell pneumatic lift PL
Separator Model ST-664-2.
The lower end of the inclined screen 67 is disposed over the
lower end ~f an endless belt conveyor 81, so that said components
falling from the inclined screen 67 are conveyed ~pwardly. The
upper end of the belt conveyor 81 is disposed over the lower end
of a further upwardly inclining belt conveyor 82, as seen in
Figures 7 and 8, the upper end of which is disposed over a
vibratory screening table 83, seen in Figures 1 and 8. The table
83 is of a conventional form used in tobacco leaf processing.
Briefly, it comprises an elongated channel-section trough 83a.
At the end adjacent the conveyor 82, the trough 83a is closed by
a transverse end wall. The opposite end of the trough is open.
~ounted within the trough and spaced a small distance below its
upper edge is a screen mesh 83b. The table 83 is connected to a
vibrator device 84 and is supported on swing supports 86, about
which the table is driven in a rapid oscillation when driven by
the device 84. Particulate material on the screen 83b travels
along the screen in the direction toward the open end of the
trough as a result of the form of the vibratory motion to which
the table is subjected. Particulate material passing throu~h the
screen 83b travels along the bottom surface 83c of the trough
83a f as a result of the vibratory motion, to an opening 83d,
through which the particulates fall to a chute 88.
The end of the table 83 opposite the conveyor 82 is disposed over
the hopper 13 and feed conveyor 11, so that material which does
not pass through the screen 83b is recycled to the hopper.
Referring again to Figure 2, the outlet at the lower end of the
tangential separator 71 connects to the interior of a hood 89,
which is intende~ to shield the relatively fine particles which
rain downwardly from the airlock in the bottom of the tangential
separator 71 from being carried to one side by drafts or cross-
currents of air. The hood 89 is positioned over one end of a
vibratory screening table g1 similar to the table 83, and
connected to a vibrator device 92 effective to move particulates
toward the opposite end of the table 91. The table 9l includes
a lower screen 91b of relatively fine mesh, and in the region of
-- 10 --
the hood ~9, an upper screen 93 of relatively coarse mesh inter-
posed between the outlet of the airlock of the tangential
separator 71 and the screen 91b, so that solids raining down-
wardly from the tangential separator device 71 are received first
on the screen 93. The screen 93 is fixed to the table 91 so that
it vibrates therewith. The screen 93 extends only a short
distance, e.g., approximately the axial extent of the tangential
separator 71, as indicated in Figure 7. Solids passing through
the screens 91b and 93 collect on the trough of the table 91, and
are moved forwardly by the vibrating action toward an opening 91d
in the table through which the screened solids pass onto the
upper surface of an intermediate portion of an endless conveyor
belt 96. This conveys the screened solids in the direction
indicated by the arrow 97 in Figure 1 to the upper surface of a
further endless conveyor belt 98, which conveys the solids in the
direction indicated by the arrow 99 in Figure 1. The conveyor
belt 98 is relatively wide, and preferably there is a vibrating
plate device (not shown) disposed between the end of the conveyor
belt 96 and the upper surface of the belt 98 on which the solids
initially fall and which tends to spread solids more or less
evenly on the upper surface of the belt 98. The vibrating plate
may be for example a rectangular plate bent into an inverted
V-section and connected to the table 83 and vibrating therewith.
In ~he operation of the apparatus, as described in more detail
later, the belt 98 receives tobacco particles and the spreading
out of the particles on the belt 98 permits the quality of the
tobacco particles product passing along the belt 98 to be
inspected visually by an operator stationed alongside the belt
98~ Preferably, the operator is provided with a vacuum nozzle
connected to a vacuum hose, so that the operator can pick ~Ip and
remove by vacuum any scraps of paper which are evident on visual
inspection.
In order to subject the solids separated at the tangential
separator 71 to a lengthy screening action, the shaking table 91
and screen 91b extend beyond the opening 91d to an end positioned
over an end of a further horizontal vibratory screening table
101 similar to tables 83 and 91, and provided with a screen 101b
- 11 -
of mesh dimensions the same as those of the screen 93. The
shaking table 101 is vibrated by a vibrator device 103. An
opening 101d is formed in the trough of the shaking table 101
adjacent the end remote from the shaking table 91, and a chute
106 extends downwardly from the opening 101d toward the upper
surface of an upwardly-inclaning endless conveyor belt 107, so
that solids passing through the screen 101b, and moved along the
table 101 by its shaking action, travel through the opening 101d,
down the chute 106, and onto the conveyor belt 107, which feeds
the solids to the inlet end of the conveyor belt 96. The end o~
the screen 101b remote from the belt 91 is positioned over a
paper waste collection box 108 which receives fragments which do
not pass through the screen 101b.
The above-mentioned chute 88 extending from the opening 83d in
the shaking table 83 is disposed over endless conveyor belt 109,
which conveys material received from the chute 88 to the upper
surface of the screen 101b of the shaker table 101.
In operation, the wrappings of cartons of cigarettes, which may
be filter or non-filter cigarettes, from which the tobacco is to
be reclaimed are removed by hand, and the intact packages are
placed in the feed hopper 13. The packages are conveyed by the
conveyor 11 to the machine 16. The packages falling downwardly
through the casing 17 are received on the upper surface of the
basket 19, and are drawn at high speed by the impeller members 31
along the inner surface of the basket in a direction generally
circumferentially of its surface, and are thereby subjected to a
disintegrating action as they are drawn over the relatively thin
blade-lilce edge surfaces of the teeth 22. This action is
effective to cut through cellulose film, paper and card packaging
materials of the intact packages, and to cut through the paper
tubes of the cigarettes. Tobacco particles tend to be liberated
from the cut-open tubes, as a result of t~e agitation to which
they are subjected as a result of impacts by the impeller members
31 and teeth 22, so that a mixture of torn and shredded cellulose
film, paper and cardboard, together with intact and severed
cigarettes, pieces of paper tube and liberated tobacco particles
~%~
is formed~ It has been found that the form of disint2grating
action which is effected by this arrangement, wherein the
cigarette packages are drawn by impeller members longitudinally
along longitudinally-extending rows of teeth, such as the teeth
22, wherein the teeth in each row project transversely toward the
teeth in the adjacent row, ~orms a disintegrated mixture without
any substantial production of small paper fibers or other parti-
cles, whether resulting from wrapping paper or cardl cigarette
tube paper, or cellulose fiber or other filters, of a particle
size the same as or smaller than the tobacco particles. The
disintegrated mixture, which may also include occasional more or
less intact cigarette packages, which fall through the elongated
openings 21 between adjacent rows of teeth, passes downwardly
through the hopper 34, and is entrained in the stream of air
passing along the horizontal portion 36 of the duct. The mixture
passes into the tangential separator device 39, and the solids,
passing downwardly through the airlock device 52 are passed into
the pneumatic lift device 62 and are cast laterally by the paddle
wheel impeller 64 along the substantially horizontal paths 66
~0 into the upflowing stream of air passing through the rectangular
chamber 63 of the device 62. The stream of air flowing upwardly
through the chamber 63 is controlled such that it is insufficient
to elevate intact cigarette packages or more or less intact
cigarette packages that may be present in the mixture, and these
fall downwardly onto the vibrating or shaking screen 67, and pass
laterally outwardly to the conveyor device 81.
The remaining components of the mix~ure, comprisiny fragments of
packages, packaging materials, intact or severed paper tubes and
tobacco particles pass upwardly in the airstream flowing through
the duct 69 and into the tangential separator 710
Desirably, the upflow of air through the chamber 63 is controlled
by adjustrnent of the speed of ~he fan 73 so that it is of such
velocity that it will not immediately entrain intact cigarettes
or cleanly-severed cigarette lengths, i.e. segments consisting of
a length of paper tube packed with more or less undisturbed
tobacco particle filler, and carry them out of the chamber 63
- 13 -
~2~
into the duct 69. Rather, the velocity of the upward airflow is
desirably controlled so that these relatively heavy intact ciga-
rettes and cleanly severed cigarette portions tend to reside in a
suspended condition inside the chamber 63, and tend to be driven
against the walls of the chamber, to impact thereon repeatedly,
as a result of the somewhat turbulent nature of the flow upwardly
through the chamber. As a result, the repeated impacts against
the inner walls of the chamber 63 tend to loosen the tobacco
particles within the cigarette paper tubes, so that the loosened
particles fall out, and the liberated particles, together with
the now empty and lightened paper tubes and tube pieces are
car~ied upwardly out of the chamber 63 and into the duct 69.
Preferably, the air flow upwardly through the chamber 63 of the
lift device 62 has a velocity in the range about 500 to 1200 ft.
per minute. At lo~er speeds, excessive quantities of fragments
tend to be separated out onto the vibrating screen 67, and with
higher speeds, there is increasing tendency for intact packages
to be carried upwardly out of the device 6~ along the duct 69 and
into the tangential separator device 71. More preferably, the
velocity of the airstream is about 600 to about 900 feet per
minute~ still more preferably, about 800 feet per minute~ Merely
by way of example, it may be mentioned that the interior
cross-section of the chamber 63 may be about 2 feet 6 inches by
about 3 feet 4.5 inches, and the airflow upwardly through the
chamber 63 may be about 6600 cubic feet per minute, at a velocity
of about 780 feet per minute.
The mixture of solid fragments passing downwardly from the
tangential separator 71 falls initially on the upper screen 93 of
the shaking table 91. The function of the relatively coarse
upper screen 93 is to impart tilting or toppling motions to the
fragments of paper and other non-tobacco fragments in the
mixture, so that tobacco particles which have lodged on top of
these fragments is not carried along with them and lost to the
recovery process. Thus, because of the relatively large openings
in the upper screen 93, as the paper fragments, other wrapping
material fragments, and empty cigarette paper tubes travel along
- 14 -
the upper surface of the screen 93, under the influence of the
vibrator motion, they tend to engage in or momentarily tip
downwardly into the relatively large openings in the screen 93,
and have a tumbling motion imparted to them, so that the bed of
fragments on the upper screen 93 proceeds forwardly in the form
of a vigorously agitated bed of fragments. The fragments are
further agitated and tumbled as they fall forwardly and
downwardly from the forward edge of the upper coarse screen 93
onto the upper surface of the lower relatively fine screen 91b.
Merely by way of example, it may be mentioned that the upper
screen 93 may be a half inch square wire mesh screenO The lower
screen 91b may be a one-eighth square wire mesh screen.
The tobacco particles fall through the screens 91a and 91b onto
the lower continuous table surface of the table 91, and, by the
vibratory motion, are carried forwardly along the lower
continuous surface to the opening 91d, through which they fall
onto the upper surface of the belt 96, which conveys them to the
conveyor belt 98. The tobacco particles passing along the
conveyor belt 9~ may, as discussed earlier, be spread laterally
on the belt and be inspected visually by an operator who has a
vacuum nozzle with which the operator can remove any visually
evident pieces of non-tobacco material such as small paper
fragments or the like. At the far end of the belt 98, the
separated tobacco particles may be received in a collection box
or the like.
The paper fragments and other non-tobacco fragments travelling
along the lower screen 91b fall from the end of the table g1 onto
the upper surface of the vibrating screen 101b of the table 101.
The end of the trough of the shaking table 91 is also disposed
above the screen 101b, so that any tobacco fragments which pass
the screen 91b beyond the opening 91d also fall onto the upper
surface of the screen 101b of the table 101.
The paper and other non-tobacco fragments, which are relatively
large compared with the tobacco particles, travel forwardly along
- 15 -
the screen lOlb under the vibratory action of the table 101, and
fall into the collection box 108. Tobacco particles which become
dislodged from th~ paper or other non-tobacco fragments on the
screen 101b, together with any tobacco particles which are
received from the shaking table 91, pass through the screen lOlb,
and travel forwardly along the trough of the table 101 below the
screen lOlb, and fall downwardly throu~h the opening 101d, pass
down the ch~te 106, and onto the upper surface of the belt 107,
and onto the belt 96, where they join the screened tobacco
particles from the table 91, and hence pass with these particles
to the belt 98 and toward collection~
Any more or less intact packages which pass laterally outwardly
from the pneumatic lift device 62 on the screen 67 are carried
upwardly by the conveyor 81 to the lower end of the conveyor 82,
which carries them to the upper surface of the screen 83b of the
screening table 83, along which they travel to the end disposed
over the hopper 13, so that they are collected by the belt 11 and
returned to the thresher device 14.
Any tobacco particles which may be carried along with such intact
or more or less intact packages tends to be dislodged from the
packages in their passage along the screen 83b, as a result of
the vibrations to which they are subjected, and therefore fall
through the screen 83b to be collected by the chute 88l from
which they are carried by the conveyor 109 to the upper surface
of the screen 101b, and travel toward collection together with
the other tobacco particles passing through the screen 102b.
Preferably, the openings of the screen 83b are relatively large,
so that any fragments smaller than intact packages and which are
carried laterally out of the pneumatic lift device 62, along with
intact packages, tend to pass through the openings of the screen
83b. Merely by way of example, it may be mentioned that the
openings in the screen 83b may be about 3~4 inch mesh openings~
The openings in the screen 101b are preferably relatively small,
e.g. 1/8 inch, so that paper and other relatively large fragments
are retained by the screen 101b and pass to the paper waste
collection box 108.
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