Apparatus for separating threshed leaf tobacco

Apparatus for separating lighter particles such as lamina containing little or no stem from tobacco particles contained in threshed leaf tobacco which comprises a plurality of tobacco particle separating units, each including a separation chamber each a fan system for establishing a generally upward air flow therein. A tobacco particle projecting mechanism is provided in each chamber for projecting tobacco particles across the generally upward air flow therein with each having structure for directing tobacco particles in cooperating relation therewith to be projected thereby. Mechanisms are provided for receiving the lighter particles carried upwardly by the air flow, the heavier particles moving downwardly within the air flow within each chamber and discharging the particles therefrom. The plurality of tobacco particle separating units are mounted in side-by-side relation in a row which includes an initial end unit and a final end unit with the tobacco particle directing structure of the initial end unit arranged to receive a supply of threshed leaf tobacco and the tobacco particle directing structure of the remaining of the plurality of units being directly connected to receive tobacco particles through a tobacco particle opening in the receiving side of the chamber of the preceding unit so that the tobacco particles projected across the chamber of the preceding unit which move across the air flow therein and pass through the opening form a tobacco particle supply directed to an associated projecting mechanism by an associated tobacco particle directing structure.

The invention relates to apparatus for separating threshed leaf tobacco, 
and more particularly to apparatus of this type which will improve the 
separation characteristics while minimizing damage to the lamina 
particles. 
The invention is particularly concerned with the separation of threshed 
tobacco leaves by air stream separation into (1) lighter particles such as 
lamina with little or no stem, and (2) heavier particles such as stem with 
or without attached lamina. Air flotation type separation apparatus is 
known, and basically includes a separation chamber having opposed sides 
and a closed fan system for establishing a generally upward flow of air 
within the chamber between the sides thereof. Successive particles from a 
supply of threshed leaf tobacco are projected from one side of the chamber 
across the chamber so that (1) lighter particles are carried upwardly by 
the airflow within the chamber, and (2) heavier particles move by gravity 
downwardly through the airflow within the chamber. A discharge system is 
provided in the upper portion of the chamber for receiving the upwardly 
carried lighter particles and discharging them from the chamber, and a 
separate discharge system is provided in the lower portion of the chamber 
for receiving the heavier particles moving downwardly by gravity and 
discharging the same from the chamber. 
In my U.S. Pat. No. 4,465,194, there is disclosed an apparatus of this type 
in which means is provided for further handling and separating projected 
particles which travel entirely across the chamber and for effecting a 
final separation of lighter particles entrained with the particles 
received in the heavier particle discharge system. The lighter particles 
separated in the apparatus are frequently subsequently shredded into a 
form useful in cigarettes. 
In the use of apparatus of the type herein contemplated, it is often the 
case that the heavier particle fraction discharging from the apparatus 
contains lighter particles clumped therewith which did not get separated 
in the operation of the apparatus. Consequently, it is often the practice 
to set up an intervening power-operated system for delivering the heavier 
particle discharge from one apparatus to the inlet of a similar apparatus 
as the threshed leaf tobacco supply thereof. In this way, a better final 
separation can be achieved. However, due to the additional handling by the 
intervening power-operated system, it is achieved in a manner which tends 
to effect damage to the lamina. It has also been the practice heretofore 
to form a stack of two separators of the type disclosed in the '194 patent 
wherein the discharge of the upper separator is disposed in immediate 
gravity feeding relation with the inlet of the lower separator. However, 
the stacked relationship is undesirable because it is generally limited to 
two separators and the upper one is difficult to control and maintain. 
There is, therefore, a need to provide an apparatus of the type described 
capable of cooperating in side-by-side relation with a similar apparatus 
without the need to provide a lamina-damaging intervening power-operated 
system. 
Accordingly, it an object of the present invention to provide a single 
apparatus which will fulfill the above-described need. In accordance with 
the principles of the present invention, this objective is obtained by 
providing an apparatus for separating lighter particles from heavier 
particles in a mixture thereof which comprises a plurality of successive 
side-by-side separation chambers constructed and arranged to enable 
particles to be continuously moved therethrough from an initial end 
chamber downstream to a final end chamber. Each of the chambers has a pair 
of opposite sides one of which is a projecting side and one of which is a 
receiving side with the receiving side of each chamber upstream of the 
final end chamber having an opening therein in immediate feed 
communicating relation with the projecting side of the next downstream 
chamber. A fan system is constructed and arranged with respect to the 
chambers to establish a generally upward air flow in each of the plurality 
of separation chambers between the opposite sides thereof. A power driven 
particle projecting mechanism associated with each chamber is disposed in 
the projecting side of the associated chamber. The power driven particle 
projecting mechanism associated with the initial end chamber is 
constructed and arranged to project particles of a mixture fed thereto 
into and across the generally upward air flow in the initial end chamber 
so that lighter particles are carried upwardly by the generally upward air 
flow within the initial end chamber and some particles including heavier 
particles move downwardly within the generally upward air flow in the 
initial end chamber. The power driven particle projecting mechanism 
associated with each chamber downstream of the initial end chamber is 
constructed and arranged to project particles fed thereto into and across 
the generally upward air flow in the associated downstream chamber so that 
lighter particles are carried upwardly by the generally upward air flow 
within the associated downstream chamber and some particles including 
heavier particles move downwardly within the generally upward air flow in 
the associated downstream chamber. The power driven particle projecting 
mechanism associated with each chamber downstream of the initial end 
chamber is constructed and arranged with respect to the adjacent upstream 
chamber so as to be disposed in immediate feed communicating relation with 
the opening in the receiving side of the adjacent upstream chamber. The 
power driven particle projecting mechanism associated with each chamber 
upstream of the final end chamber is constructed and arranged to project 
the particles fed thereto into and across the generally upward air flow in 
each upstream chamber in such a way that some particles reach the 
receiving side of each upstream chamber in a position to enter the opening 
therein in immediate feed communicating relation with the adjacent 
downstream power driven particle projecting mechanism so as to be 
immediately projected thereby into and across the generally upward air 
flow in the chamber associated therewith. A lighter particle receiving and 
moving assembly is constructed and arranged with respect to the chambers 
to receive the lighter particles carried upwardly by the generally upward 
air flow within the chambers and move the same in such a way as to enable 
the lighter particles to be discharged from the chambers. A heavier 
particles receiving and moving assembly is constructed and arranged with 
respect to the chambers to receive the particles including heavier 
particles which move downwardly within the generally upward air flow in 
the chambers and move the same in such a way as to enable them to be 
discharged from the chambers. 
Another object of the present invention is the provision of an apparatus of 
the type described in which the heavy particle receiving and moving 
assembly constitutes an upper flight of a separate endless foraminous 
conveyor in each chamber. The separate endless foraminous conveyor in each 
chamber upstream of the final end chamber being constructed and arranged 
such that the upper flight moves the particles received thereon in such a 
way as to be discharged into the opening in the receiving side thereof. 
The separate endless foraminous conveyor in the final end chamber is 
constructed and arranged such that the upper flight moves the particles 
received therein in such a way as to be discharged into an outlet at the 
receiving side thereof. 
The provision of a separate endless foraminous conveyor in each chamber 
upstream of the final end chamber constructed and arranged as indicated 
above is advantageous in that lighter particles which may be entrained 
with heavier particles received on the separate endless foraminous 
conveyors are immediately projected across the generally upward air flow 
in the next downstream chamber thereby presenting the possibility that 
such entrained lighter particles may be set free to be received by the 
lighter particle receiving and moving assembly of the next downstream 
chamber. 
Another object of the present invention is to provide a method of 
separating lighter particles from heavier particles in a mixture thereof 
utilizing a plurality of successive side-by-side separation chambers for 
continuous movement of particles therethrough from an initial end chamber 
downstream to a final end chamber. Each of the chambers has a pair of 
opposite sides one of which is a projecting side and one of which is a 
receiving side with the receiving side of each chamber upstream of the 
final end chamber having an opening therein which is disposed in immediate 
feed communicating relation with the projecting side of the next 
downstream chamber. A generally upward air flow is established in each of 
the plurality of separation chambers between the opposite sides thereof. 
Particles from the projecting side of each chamber are projected into and 
across the generally upward air flow therein so that lighter particles are 
carried upwardly by the generally upward air flow in each chamber and 
particles including heavier particles move downwardly through the 
generally upward air flow in each chamber, the particles projected from 
the projecting side of the initial end chamber being the lighter and 
heavier particles of the mixture. Some of the particles are caused to be 
projected from the projecting side of each chamber upstream of the final 
end chamber to reach the receiving side thereof and to pass through the 
opening therein to immediately become particles projected from the 
projecting side of the next downstream chamber into and across the 
generally upward air flow in the next downstream chamber. The lighter 
particles are carried upwardly by the air flow within the chamber and 
moved in such a way as to enable them to be discharged from the chambers. 
The particles including heavier particles which move downwardly within the 
generally upwardly air flow are received in the chambers and moved in such 
a way as to enable them to be discharged from the chambers. 
Another object of the present invention is the provision of a method of the 
type described where threshed leaf tobacco constitutes the particle being 
separated and wherein the particles including the heavier particles which 
move downwardly through the generally upward air flow in each chamber 
upstream of the final end chamber are received in each upstream chamber 
and moved in such a way as to be discharged into the opening in the 
receiving side of each upstream chamber to immediately become particles 
projected from the projecting side of the next downstream chamber. The 
particles include heavier particles which move downwardly through the 
generally upward air flow in the final end chamber and are received 
therein and moved in such a way as to be discharged through an outlet at 
the receiving side thereof. 
The above object and other objects of the present invention will become 
more apparent during the course of the following detailed description and 
appended claims. 
The invention may best be understood with reference to the accompanying 
drawings wherein an illustrative embodiment is shown.

Referring now more particularly to the drawings, there is shown therein an 
apparatus, generally indicated at 10, for separating threshed leaf tobacco 
into (1) lighter particles such as lamina containing little or no stem, 
and (2) heavier particles such as lamina with attached stem or naked 
stems. The apparatus 10 includes two separation devices, generally 
indicated at 12 and 14, which are of similar construction. Each separation 
device 12 and 14 is capable of operating alone or in cooperating 
side-by-side relation with a similar device. Thus, while two separation 
devices 12 and 14 are shown, it will be understood that the invention 
contemplates that the apparatus 10 can include more than two similar 
separation devices. 
Set forth below is a description of the structure of the separation device 
12 and its mode of operation (1) alone and (2) in conjunction with the 
similar separation device 14. It will be understood that, since the 
separation devices 12 and 14 are similar, a description of separation 
device 12 will be sufficient to provide an understanding of the 
construction and operation of the separation device 14. Accordingly, the 
same reference numerals utilized in the description of separation device 
12 will be applied to separation device 14. 
As shown, the separation device 12 provides a housing structure defining a 
separation chamber 16 having a tobacco projecting side 18, an opposite 
tobacco receiving side 20, a lower air inlet end 22, and an upper air 
outlet end 24. 
A variable plural path fan circulating system, generally indicated at 26, 
is mounted exteriorly of the separation chamber 16 with its suction side 
connected with the upper air outlet end 24 thereof and the pressure side 
connected with the lower air inlet end thereof. The fan system 26 is 
operable to establish a generally upward flow of air within the separation 
chamber 16. 
Mounted in the tobacco inlet side 18 of the separation chamber 16 is an 
inlet 28 for receiving a supply of threshed leaf tobacco downwardly 
therethrough. The inlet 28 delivers the supply of threshed leaf tobacco 
downwardly into cooperating relation with a threshed leaf tobacco 
projecting mechanism, generally indicated at 30, operable to project the 
supply of threshed leaf tobacco from the tobacco inlet side 18 of the 
separation chamber 16 toward the opposite tobacco outlet side 20 thereof, 
so that (1) lighter particles are carried upwardly by the flow of air 
within the separation chamber 16, and (2) heavy particles move by gravity 
downwardly through the flow of air within the separation chamber 16. 
A lighter particle receiving and discharging system, generally indicated at 
32, is provided in the upper air outlet end 24 of the separation chamber 
16 for receiving the lighter particles carried upwardly by the flow of air 
within the separation chamber and discharging the lighter particles 
therefrom. Lighter particle receiving and discharge system may also be any 
known centrifugal device commonly used in the tobacco industry. A heavier 
particle receiving and discharging system, generally indicated at 34, is 
provided in the lower air inlet end 22 of the separation chamber 16 for 
receiving some of the heavier particles moving by gravity downwardly with 
the upward air flow and discharging them from the separation chamber 16. 
Most of the heavier particles contact the receiving wall 20 and fall by 
gravity directly into the outlet 36. 
In accordance with the principles of the present invention, the discharging 
means of the system 34 is an outlet 36 formed in the outlet side 20 of the 
separation chamber 16 for receiving heavier particles downwardly 
therethrough. It will be noted that the lower end of the outlet 36 is at a 
vertical level slightly above the vertical level of the upper end of the 
inlet 28 so as to deliver the heavier particles downwardly from the outlet 
36 directly into the inlet 28 of a similar device, such as the device 14. 
The heavier particle receiving and discharging system 34 also preferably 
includes an endless foraminous conveyor mechanism, generally indicated at 
38, having openings of a size (1) to enable the upward air flow to pass 
therethrough and (2) to receive and prevent passage of heavier particles 
therethrough. The conveyor mechanism 38 is operable to deliver heavier 
particles received thereon downwardly into the outlet 36. 
It will also be noted that the outlet 36 is disposed in a position to 
receive threshed leaf tobacco projected by the threshed leaf tobacco 
projecting system 30 which has not been (1) carried upwardly by the air 
flow in the separation chamber 16 and received as lighter particles by the 
lighter particle receiving and discharging system or (2) moved downwardly 
through the upward air flow in the separation chamber and received as 
heavier particles by the heavier particle conveyor mechanism 38. 
The separation chamber 16 may be formed of any desirable construction. In 
the drawings, the separation chamber 16 is schematically illustrated to be 
formed of sheet metal. It will be understood that a rigid framework for 
retaining the sheet metal (not shown) normally would be provided. As 
shown, the separation chamber 16 is of generally rectangular configuration 
with the lower portion being somewhat enlarged, and the upper portion 
being generally of upwardly tapering design configuration which aids in 
separating the lighter particles by increasing the velocity of the upward 
air flow as it passes therethrough. 
The fan circulating or airflow establishing system 26, as shown, includes a 
fan blade assembly 40, suitably journalled for rotational movement about a 
vertical axis within a housing of conventional fan configuration. The fan 
blade assembly 40 is driven by a suitable variable speed motor 42 through 
a suitable motion transmitting mechanism, such as a belt and pulley 
assembly 43. The fan housing includes an arcuate peripheral wall 44 which 
extends somewhat less than 360.degree. so as to provide for a tangential 
discharge chute 46 which constitutes the pressure side of the fan blade 
assembly 40. The lower end of the suction side of the fan blade assembly 
40 communicates directly with the upper end of the upper air outlet end 24 
of the separation chamber 16, and a top wall of the fan section closes the 
upper end thereof. 
The tangential discharge 46 of the fan blade assembly 40 is connected with 
the upstream end of a generally vertically elongated C-shaped main 
pressure side duct section 48, the downstream horizontal end portion of 
which connects with the upstream end of a downstream outlet duct section 
50 which has a downstream ending just below the endless heavier particle 
conveyor mechanism 38 and which discharges thereto through a suitable 
perforated or apertured diffusing plate or screen 52, such as shown in 
FIG. 3. 
As best shown in FIG. 2, the main pressure side duct section 48 includes 
adjustable dampers 54 which can be used for controlling the amount of flow 
in the duct section downstream thereof in lieu of the variable speed fan 
motor 42. Moreover, a bleed off duct section 55 is provided at the 
tangential discharge chute 46 so as to bleed off about 10% of the full 
capacity of the fan to maintain a negative pressure on the system and 
remove dust for product and environmental purposes. It will be understood 
that a manually controlled fresh air inlet (not shown) may be provided in 
the system 26 preferably on the suction side of the fan 40. 
Referring now more particularly to FIG. 3, there is shown therein an 
adjustable air flow dividing system, generally indicated at 56. As shown, 
the system 56 includes a vertically extending divider wall 58 having an 
upstream end within the horizontal downstream end portion of the main duct 
section 48 and a downstream end which terminates just below the diffusing 
plate 52. The diffusing plate 52, like the conveyor 38, slopes upwardly 
from the inlet side 18 of the separation chamber 16 to the outlet 36 
therein adjacent the outlet side 20. The outlet duct section 50 diverges 
upwardly in a direction toward the inlet and outlet sides of the 
separation chamber 16. The vertical divider wall 58 divides the full flow 
within the main duct section 48 into two divided paths one at the inlet 
side 18 of the separation chamber 16 and the other at the outlet side 20 
thereof. 
The system 56 also includes a pair of divider walls 60 on opposite sides of 
the vertical divider wall which divides each of the aforesaid two paths 
into two paths. The horizontal divider walls 60 extending horizontally 
from their upstream ends adjacent the upstream end of the vertical wall 58 
and curve upwardly at the downstream ends into abutting relation to a pair 
of vertical divider walls 62. The divider walls 58, 60 and 62 thus serve 
to divide the full air flow within the main duct section 48 into four 
separate air flow paths which are in quadrant formation at the downstream 
end thereof at the diffusing plate 52. 
The system 56 includes means at the upstream end of these four separate 
flow paths for varying the proportion of the full air flow within the main 
duct section 48 which is directed to the four separate paths. FIG. 3 
illustrates the flow proportion varying means as including a vertical vane 
64 pivoted, as at 66, adjacent the upstream end of the vertical divider 
wall 58 and a horizontal vane 68 pivoted, as at 70, adjacent the upstream 
end of the horizontal divider walls 60. In order to accommodate the 
horizontal vane 68, the vertical vane has an angular section 72 removed 
therefrom. 
Referring now more particularly to FIG. 4, it will be noted that the 
heavier particle endless foraminous conveyor 38 which is illustrated 
schematically as an endless screen type conveyor in FIG. 1 preferably is 
an endless conveyor of the type which includes a pair of transversely 
spaced endless chains 74 each trained about a pair of sprocket wheels 76 
and a plurality of perforated metal slats 78 pivotally interconnected, as 
by piano hinges, and extending transversely between the links of the 
chains. The perforations in the slats enable the flow of air upwardly 
therebetween, first through a lower return flight and then upwardly 
through an upper operative flight. The size of the perforations in the 
slats 78 is such that heavier particles moving downwardly within the 
upward air flow as it enters into the lower air inlet end 22 of the 
separation chamber 16 cannot pass therethrough. In this way, heavier 
particles received on the upper operative flight of the endless foraminous 
conveyor 38 will be carried thereon toward a discharge position above the 
outlet 36, as the endless conveyor passes over the outlet side sprocket 
wheel 76. Every second slat 78 has a metal cleat 79 on the outside to lift 
and carry the heavy particles which come into contact with the conveyor. 
FIG. 4 also shows that the inlet 28 for the threshed leaf tobacco supply is 
defined by spaced walls 80 and 82. The wall 80 has its lower end portion 
curved to form part of a peripheral housing for the threshed leaf tobacco 
projecting mechanism which preferably is in the form of a paddle wheel 
type rotary winnower 30. An adjustable peripheral wall section 84 is 
disposed in cooperating relation with the curved portion of the wall 80 
and includes a tangential discharge end which serves to determine the 
direction that the threshed leaf tobacco is projected from the inlet side 
18 of the separation chamber toward the outlet side 20 thereof. The 
discharging wall section 84 is adjustable about the axis of rotation of 
the rotary winnower 30 through a limited angular range so as to adjust the 
angle of projection. Finally, it will be noted that wall 82 provides a 
fixed peripheral wall section for the winnower 30. The construction of the 
inlet 28 is therefore to direct the supply of threshed leaf tobacco 
received downwardly therein, downwardly into cooperating relation with the 
winnower 30. 
As shown in FIGS. 1 and 2, the rotary winnower 30 is driven by a suitable 
variable speed motor 86 through a suitable motion transmitting mechanism 
such as belt and pulley assembly 88. A fixed speed motor 90 is also 
provided for driving the endless foraminous conveyor 38 through a suitable 
motion transmitting assembly, such as belt and pulley assembly 92. 
Referring now more particularly to FIGS. 1 and 5, a preferred lighter 
particle receiving and discharging system 32 is shown. It will be 
understood that lighter particle receiving and discharge system may also 
be any known centrifugal device commonly used in the tobacco industry. 
However, the preferred embodiment shown includes an exit chamber 94 
communicating with the outlet side of the associated separation chamber 16 
at the upper air outlet end 24 thereof. The lighter particle receiving and 
discharging system 32 also includes an endless foraminous conveyor, 
generally indicated at 96, similar to the conveyor 38. Here again, the 
conveyor 96 is shown schematically in FIG. 1 as an endless screen. It is 
within the contemplation of the present invention that the conveyor 96 be 
self contained within each device 12 or 14 in a manner similar to conveyor 
38. However, it is preferable that the plural conveyor assemblies 96 be 
integrated into one. As shown, the device 12 includes laterally spaced 
structures for mounting laterally spaced pairs of spaced sprocket wheels 
in each device, one pair of spaced sprocket wheels 98 are mounted in the 
inlet side 18 of the device 12 and one pair of sprocket wheels 100 are 
mounted in the outlet side 20 of the device 14. Each sprocket wheel 98 and 
associated sprocket wheel 100 has a link chain 102 trained thereabout and 
a series of perforated slats 104 are pivotally interconnected, as by piano 
hinges and extend transversely between the links of the chains 102 so as 
to define a lower operative flight extending horizontally through the 
separation chamber 16 and exit chamber 94, of the device 12 and then 
through the separation chamber 16 and exit chamber 94 of the device 14. 
The integrated endless foraminous conveyor 96 is driven by a variable 
speed motor 106 through a suitable motion transmitting mechanism, such as 
a belt and pulley system 108 connected with a shaft 110 on which both 
sprocket wheels 100 are fixed. The motor moves the foraminous conveyor 96 
in a direction wherein the lower operative flight moves from left to right 
as shown in FIGS. 1 and 5. The perforations in the conveyor slats 104 are 
sufficient to allow for the upward flow of air therethrough and 
sufficiently small to prevent the movement of lighter particles 
therethrough. The lamina or lighter particles which move upwardly within 
the separation chamber 16 by the upward air flow therein are received on 
the operative flight of the foraminous conveyor 96 for movement therewith 
from the separation chamber 16 into the adjacent exit chamber 94. 
A suitable barrier system is provided for enabling the lower operative 
flight of the foraminous conveyor 96 with attached lamina to move from 
each separation chamber 16 into the associated communicating exit chamber 
94. As shown, the barrier system includes a power-driven paddle wheel type 
winnower 112 between the separation chamber 16 and the adjacent exit 
chamber 94 in a position below the operative flight of the foraminous 
conveyor 96. The paddle wheel winnower 112 is mounted for power-driven 
rotation about a horizontal transverse axis by a suitable variable speed 
motor 114 through a suitable motion transmitting mechanism, such as belt 
and pulley assembly 116. Each paddle wheel winnower 112 is mounted in a 
position such that its upper periphery is disposed in cooperating relation 
with the downwardly facing surfaces of the lower operative flight of the 
endless foraminous conveyor 96. Each paddle wheel winnower is driven by 
its motor 114 in a direction such that the upper periphery thereof will 
move at the speed and in the direction of the operative flight so that 
lighter particles such as lamina which are moved upwardly in the 
associated separation chamber 16 by the flow of air therein are caused to 
move upwardly into engagement with the downwardly facing surfaces of the 
operative flight of the endless foraminous conveyor 96 by virtue of the 
direct communication of the suction side of the associated fan blade 
assembly 40 directly above the operative flight and the associated return 
flight. These lighter particles which are engaged on the downwardly facing 
surfaces of the operative flight of the conveyor 96 are thus movable with 
the operative flight past the associated paddle wheel winnower 112, each 
of which serves to prevent flow of air between the associated separation 
chamber 16 and exit chamber 94 at a position below the operative flight. 
Each barrier system may also include upper baffle members 118 and box-like 
baffle members 120 between the operative flight and the return flight of 
the conveyor 96 to block the flow of air therebetween. 
Finally, it will be noted that a stripping paddle wheel winnower 122 is 
mounted in the exit chamber 94 of the device 14 adjacent the leading end 
of the operative flight therein. The exit chamber 94 of the device 14 is 
completed by an end structure 124. The winnower 122 is power-driven in an 
opposite direction to that of the associated winnower 112 so as to strip 
any lamina that might adhere to the downwardly facing surface of the 
operative flight of the endless foraminous conveyor 96. 
It will be noted that, since there is no upward flow of air in any of the 
exit chambers 94, there is no longer air flow bias maintaining the lamina 
in engagement with the downwardly facing surfaces of the operative flight 
of the endless foraminous conveyor 96 as is the case in the separating 
chambers 16. Consequently, as the lighter particles move into the exit 
chambers 94, these lighter particles are free to move downwardly by 
gravity from the operative flight within the associated exit chamber 94. 
Mounted in the bottom portion of each exit chamber is an endless conveyor 
126 which includes an upper horizontally operative run on which the lamina 
are deposited. Each endless conveyor 126 is powered by a fixed speed motor 
128 which serves to move the operative run in a direction to discharge the 
lamina supported thereon. Unloading may also be accomplished by 
conventional known centrifugal devices as shown in FIGS. 6 and 9. 
The particles received downward within the outlet 36 of the device 12 which 
includes heavier particles and lighter particles which have not been 
carried upwardly within the separation chamber 16 and been received and 
discharged therefrom by the associated lighter particle receiving and 
discharging system 32 forms the threshed leaf tobacco supply for the 
device 14 which moves directly downwardly into the inlet 28 thereof for 
direction into cooperating relation with the projecting winnower assembly 
30 thereof. 
The arrangement whereby the particles discharging from the outlet 36 of the 
initial device 12 pass directly into the inlet 28 of the next adjacent 
device 14 ensures a minimum damage with respect to any lamina or lighter 
particles which pass with the heavier particles through the outlet 36 of 
the initial device 12. 
Referring now more particularly to FIGS. 6-9 of the drawings, there is 
shown therein an apparatus, generally indicated at 210, for separating 
threshed leaf tobacco into (1) lighter particles such as lamina containing 
little or no stem, and (2) heavier particles such as lamina with attached 
stem or naked stems. The apparatus 210 includes a sheet metal structure 
providing three side-by-side separation chambers, generally indicated at 
212, 214, and 216. While there are shown three separation chambers; 
namely, an initial end chamber 212, a middle chamber 214, and a final end 
chamber 216, it is within the contemplation of the present invention to 
provide two, or more than three separation chambers. A fan circulating 
system, generally indicated at 218, is associated with each separation 
chamber for establishing a generally upward flow of air within the 
associated separation chamber. The initial end chamber 212 has associated 
with a projecting side thereof a threshed leaf tobacco projecting 
mechanism, generally indicated at 220 which is operable to project 
threshed leaf tobacco from the projecting side of the chamber toward an 
opposite receiving side thereof, so that (1) a portion of the lighter 
particles is carried upwardly by the flow of air within the initial end 
chamber, (2) a portion of the heavy particles moves downwardly through the 
flow of air within the initial end chamber, and (3) the remaining 
particles pass to the opposite receiving side of the initial end chamber 
212. 
The middle chamber 214 includes a similar threshed leaf tobacco projecting 
mechanism, generally indicated at 222, for receiving the remaining 
particles which pass to the opposite receiving side of the initial end 
chamber 212, and projecting the same into the middle chamber 214 to be 
acted upon by the upward flow of air therein in a similar manner. The 
final end chamber 216 also includes a corresponding threshed leaf tobacco 
projecting mechanism, generally indicated at 224, which serves to project 
the remaining particles from the middle chamber 214 into the final end 
chamber 216. 
Mounted in the opposite side of the final end chamber 216 is a reverse 
threshed leaf tobacco projecting mechanism or a reprojecting mechanism, 
generally indicated at 226, which is operable to receive the remaining 
particles passing to the opposite receiving side of the final end chamber 
216 and to project them back across the generally upward flow of air 
therein in a path below the path of tobacco particles projected by the 
projecting mechanism 224 so that (1) remaining lighter particles are 
carried upwardly by the flow of air within the final end chamber 216, and 
(2) remaining heavier particles move downwardly through the flow of air 
within the final end chamber. 
If desired, a similar reprojecting mechanism 228 may be provided in the 
initial end chamber 212 in a position spaced below the receiving position 
where the remaining tobacco particles projected by the projecting 
mechanism 220 are received prior to being projected by the middle 
projecting mechanism 222. If desired, a power driven rotary mechanism 230 
may be mounted in the lower portion of the receiving entrance for the 
projecting mechanism 222. The purpose of the power driven rotary mechanism 
230, which rotates in a clockwise direction as shown in FIG. 6, is to 
prevent tobacco particles from accumulating in the receiving entrance. The 
rotary mechanism 230 breaks up any clumps and tends to deliver the 
released particles into the projecting mechanism 222. All of the remaining 
tobacco particles projected by the projecting mechanism 220 which pass to 
the opposite receiving side of the initial chamber 212 which do not pass 
into the projecting mechanism 222 will be reprojected back across the 
upward flow of air in the initial end chamber in a path below the path 
which the tobacco particles projected by the projecting mechanism 222 
take. The reprojected particles can contain some lighter particles that 
should have been carried upwardly during the initial pass across the air 
flow but for one reason or another were not, as, for example, because of 
clumping. The power driven nature of both the rotary mechanism 230 and 
reprojecting mechanism 228 tends to break up clumps thus freeing otherwise 
restrained lighter particles for movement upwardly by the air flow during 
the return pass. 
A similar reprojecting mechanism 232 and rotary mechanism 234 may be 
provided in the middle chamber 214 as well. It will be understood that the 
reprojecting mechanisms 228 and 232 and the rotary mechanisms 230 and 234 
are optional in the three unit apparatus 210 shown. The reprojecting means 
226 in the final end chamber 216 is preferable but may also be eliminated 
if desired. Reprojection assumes a greater importance as the number of 
units is diminished. 
A heavier particle receiving and discharging system, generally indicated at 
236, is commonly provided in the lower end portions of all of the 
separation chambers 212, 214, and 216 for receiving the heavier particles 
therefrom. A lighter particle receiving and discharging system is also 
provided. However, as shown, the system consists of three lighter particle 
receiving and discharging mechanisms 238 of generally identical 
construction, in the upper end portions of the separation chambers 212, 
214, and 216 respectively for receiving the lighter particles carried 
upwardly by the flow of air within each successive separation chamber and 
discharging the lighter particles therefrom. 
The separation chambers may be formed of any desirable construction. 
Preferably, they are of substantially identical construction except for 
certain variations to be hereinafter more fully explained. In the 
drawings, the chambers are schematically illustrated to be formed of sheet 
metal. It will be understood that a rigid framework for retaining the 
sheet metal (not shown) normally would be provided. As shown, each chamber 
is of generally rectangular configuration, including a projecting side 
wall 240, and an opposite receiving side wall 242, with a lower end 
portion 244 being somewhat enlarged, and an upper end portion 246 being 
generally of upwardly tapering design configuration which aids in 
separating the lighter particles by increasing the velocity of the upward 
air flow as it passes therethrough. 
The fan circulating or air flow establishing system 218 for each chamber 
may assume any desired configuration. As shown, each system includes a 
rotary centrifugal fan blade assembly 248 suitably journalled for 
rotational movement, by a variable speed motor assembly 250 about a 
horizontal axis within a fan housing 252 of conventional centrifugal fan 
configuration, that is, the fan housing 252 is in the form of side walls 
interconnected peripherally by an arcuate peripheral wall which extends 
somewhat less than 360.degree. so as to provide for a tangential discharge 
254 which constitutes the pressure side of the fan blade assembly 248. 
Regulating dampers may be installed in the discharge duct to control flow 
instead of fitting a variable speed motor. 
As best shown in FIG. 6, the tangential discharge 254 includes a filtered 
exit controlled by a pivoted damper vane 255 which can be moved into 
different adjusted positions to control the amount of air circulated and 
to allow a certain amount to pass into the atmosphere preferably after 
being filtered. Instead of a pivoted damper vane, a fixed scoop may be 
provided to bleed-off about 10% of the recirculating air. The hollow 
central portion of each fan blade assembly 248 communicates directly with 
an axial inlet 256 of frustoconical design, the small diameter end of 
which is secured to one side of the fan housing 252 in interior 
communicating relation therewith. 
The tangential discharge 254 of each fan blade assembly 248 is connected 
with a generally elongated angular duct section 258, the lower end of 
which curves inwardly and communicates interiorly with the lower end 
portion 244 of the associated separation chamber. As best shown in FIG. 6, 
three baffle plates 260 serve to distribute the air from the associated 
duct section 258 into the lower end portion 244 of the associated chamber 
so as to establish a generally upward flow of air within the chamber. In 
the arrangement shown, each duct section 258 has an adjustable damper 262 
mounted in the central portion thereof. 
The threshed leaf tobacco projecting mechanism 220 which is utilized in the 
projecting side wall 240 of the initial end chamber 214 is illustrated as 
including a paddle wheel type winnower assembly 264, which is rotatable 
about a transverse horizontal axis and suitably power-driven by a variable 
speed motor (not shown). It will be understood that other types of 
arrangements may be utilized such as described in U.S. Pat. No. 4,475,562. 
As shown, the projecting side wall 240 has an inlet opening provided 
therein which cooperates exteriorly with a shroud structure 266 which 
leads to and is disposed in cooperating relation with the winnower 
assembly 264 so as to direct a tobacco particle supply into the winnower 
assembly 264 to be projected thereby. As shown, the shroud structure 266 
is mounted in cooperating relation with the periphery of the winnower 
assembly 264 and a vane 268 is adjustably mounted about a horizontally 
extending axis in a position tangentially inwardly of the lower periphery 
of the winnower assembly 264 so that by adjusting the angle of the vane 
268, the direction within the initial end chamber 212 across which the 
winnower assembly 264 projects the threshed leaf tobacco can be varied. 
A suitable supply of threshed leaf tobacco, shown schematically at 270, is 
fed to the shroud structure 266 so that successive particles are picked up 
by the winnower assembly 264 and projected into the initial end chamber 
212 for movement across the generally upward flow of air therein. The flow 
rate of the upward flow of air, which is separately controlled by the 
variable speed motor 250 and/or adjustable damper 262 associated with 
chamber 212, is such that lighter particles, such as lamina containing 
little or no stem, are carried upwardly by the air stream within the 
separation chamber, while heavier particles, such as lamina with attached 
stem or naked stems, move downwardly through the flow of air by gravity 
within the initial end chamber 212. In addition, a remaining portion of 
the particles moves to the opposite receiving side wall 242 where the 
particles pass through an opening 272 therein and are directed to the 
threshed leaf tobacco projecting mechanism 222 associated with the middle 
chamber 214 or to the reprojecting mechanism 228 below the opening 272. 
The reprojecting mechanism 228 is also preferably in the form of a paddle 
wheel rotary winnower which has a suitable backing plate structure 
operatively associated therewith. The rotary device 230 is also preferably 
in the form of an unshrouded smaller power-driven rotary paddle winnower. 
The projecting mechanism 222 of the middle chamber 214 consists essentially 
of a paddle wheel type winnower assembly 274, variable speed power-driven 
about a horizontally extending transverse axis within a shroud structure 
276 which extends in enclosing relation from the opening 272 in the 
receiving side wall 242 of the middle chamber 214 in cooperating relation 
with respect to the winnower assembly 224, and there is also provided a 
vane 276 which is movable about a horizontally extending axis parallel 
with the axis of the winnower. The vane 276 and variable speed drive for 
the winnower 274 can be adjusted to adjust the direction and velocity 
which the remaining particles are projected into the associated chamber 
214 so that as the particles move across the generally upward flow of air 
therein, the lighter particles will be carried upwardly by the flow of 
air, which is separately controlled as before, into the upper portion of 
the chamber, and the heavier particles will be moved downwardly by gravity 
through the flow of air into the lower portion of the separation chamber, 
while a remaining portion of the particles will move across the chamber to 
the opposite side wall 242 which likewise is provided with a similar 
opening 278 which, in turn, connects with a similar shroud structure 280 
containing a similar winnower assembly 282 with a similar vane 284 for 
projecting the tobacco particles received across the final end chamber 
216. Also, as before, the remaining particles received at the receiving 
side wall 242 which do not pass through the opening 278 or are assisted 
therein by rotary device 234 are led into the reprojecting mechanism 232, 
which serves to project the tobacco particles back across the central 
chamber 214 in a path below the projection path of the projecting 
mechanism 220 thereof. 
At the opposite side wall 242 of the final end chamber 216, the remaining 
particles are received by the reprojecting mechanism 226. Here, again, the 
reprojecting mechanism 226, like the reprojecting mechanism 232 of the 
central chamber 214, is preferably in the form of a variable speed 
power-driven paddle wheel winnower assembly rotatable about a horizontal 
axis adjacent the opposite receiving side wall 242 having a backing plate 
in a position to receive the remaining particles which have passed to the 
receiving side wall 242 and to project the same back across the final end 
chamber 216 so that the particles will be separated in the manner 
previously indicated with the lighter particles moving upwardly and the 
heavier particles moving downwardly. 
The heavier particle receiving and discharging system 236 comprises 
essentially an endless perforated or foraminous conveyor assembly which 
may be of any conventional design and includes an initial end roller 286 
mounted in the lower end portion 244 of the initial end chamber 212 at a 
position adjacent the projecting side wall 240 thereof, and a final roller 
288 disposed in the lower portion of the final end chamber 216, in a 
position spaced slightly from the receiving side wall 242 thereof. The 
endless perforated or foraminous conveyor assembly 236 includes an endless 
foraminous belt providing upper operative flight 290 extending through the 
lower portion of all of the chambers from the roller 286 to the roller 
288, and a parallel lower return flight 292 extending from the roller 288 
to the roller 286. 
The endless foraminous conveyor 236 extends between adjacent chambers by 
means of barrier assemblies, each of which includes a flapped lower wall 
294 extending below the lower return flight 292, a central boxlike barrier 
296 extending between the upper and lower flights 290 and 292, a flapped 
upper wall 298 spaced above the upper operative flight 290, and a pair of 
flexible flaps 300 extending downwardly from the ends of each upper wall 
298. The conveyor assembly 236 includes a suitable driving motor (not 
shown), so that the upper operative flight 290 moves from the roller 286 
toward the roller 288, and the return flight moves in the opposite 
direction. 
It can be seen that heavier particles which fall by gravity through the 
upward flow of air in each of the separation chambers will come to rest on 
the upwardly facing surfaces of the upper operative flight 290 of the 
endless foraminous conveyor assembly 236. The flaps 300 allow the upper 
operative flight 290 and heavier particles carried thereby to move between 
adjacent chambers, while preventing flow of air between adjacent chambers. 
It will be noted that heavier particles will be discharged as they move 
with the upper operative flight 290 over the roller 288, discharging the 
particles downwardly through a discharge chute 302. Lighter particles 
previously trapped or shadowed by heavier particles may have a third 
chance of moving upward from the fluidizing effect above the conveyor 236. 
The lighter particle receiving and discharging system could be the same as 
the system 32 of the apparatus 10. However, FIGS. 6-9 illustrate an 
alternative system in the form of three separate mechanisms 238 such as 
known screening separators or tangential separators. As shown, each 
mechanism 238 includes a screening chamber 304 of generally cylindrical 
construction having a narrow Venturi-like inlet 306 which extends 
tangentially from the extremity of the upper end 246 of the associated 
chamber into the upper end of the screening chamber 304. Rotatably mounted 
in the screening chamber is a cylindrical screen assembly 308, one 
interior end of which is communicated through an associated screening 
chamber end wall with the suction side of the associated frustoconical 
axial fan inlet 256. In this way, the upward flow of air in each chamber 
is caused to flow through the tangential inlet 306 at the upper end 246 
thereof, into the screening chamber 304, through the rotary screen 
assembly 308 and then axially through the fan inlet 256 to be 
recirculated. 
The screening separator acts like a horizontal cyclone. The centrifugal 
force causes most of the solid particles to hug the peripheral wall and 
discharge through the airlock. Only light particles which remain in 
suspension contact the rotary screen. 
The lighter tobacco particles carried by the air flow into the screening 
chamber 304 are prevented from being recirculated with the air by the 
cylindrical screen assembly 308. The screen assembly 308 is rotated as by 
a motor 310 and a suitable motion transmitting assembly 312 at a speed 
sufficient to cause any tobacco particles which engage the periphery of 
the screen assembly 308 by virtue of the air flow to be thrown by 
centrifugal action therefrom to the interior periphery of the screening 
chamber wall which directs them downwardly to a rotary plug or particle 
discharging mechanism 314 rotatably mounted in the lower portion of the 
screening chamber. 
The rotary discharging mechanism which is driven by a suitable motion 
transmitting assembly by the motor 310 serves the dual function of 
preventing air suction from the exterior of the screening chamber 308 
while at the same time allowing and, indeed, positively assisting the 
tobacco particles directed downwardly in the screening chamber 308 to exit 
exteriorly therefrom. As shown, a conveyor assembly 318 receives the 
lighter tobacco particles discharged from the screening chamber 308 and 
conveys them to a point of further use or handling. 
Referring now more particularly to FIG. 9, there is shown therein another 
form of apparatus 410 embodying the principles of the present invention. 
The apparatus 410 is like the apparatus 210 in most respects and, 
consequently, parts of the apparatus 410 which correspond substantially 
identically with corresponding parts of the apparatus 210 are given 
corresponding reference numerals and will not be specifically described. 
Instead, the description of the apparatus 410 will be limited to the areas 
of modification and change which are embodied therein with respect to the 
apparatus 210. A primary change is that the apparatus 410 illustrates the 
option of the apparatus 210 where the reprojecting mechanisms 228 and 232 
in the initial end chamber 212 and the central chamber 214 respectively 
are eliminated together with the associated rotary devices 230 and 234. It 
will be noted that, in conjunction with the elimination of these 
mechanisms, modified shroud structures 412 and 414 are provided instead of 
the configuration of the shroud structures 276 and 280 previously 
provided. As shown, the shroud structures 412 and 414 are more similar to 
the construction of the initial end chamber shroud structure 266 with the 
upper lead in portion essentially eliminated. Moreover, it will be noted 
that the shroud structures 412 and 414 extend from a position within the 
associated chambers 210 and 214 through the associated openings 272 and 
278. However, rotary devices 230 and 234 may be installed on tip of 
extended shroud to eliminate leaves draping over this extension. 
It will be understood that, in the operation of the apparatus 410, most of 
the remaining particles which move across the initial end chamber 210 will 
pass through the opening 272 and into the projecting winnower 274 
cooperating with shroud structure 412 and those particles which may reach 
the receiving side wall 242 below the opening 272 may be discharged on the 
large particle endless conveyor flight 290. Any light particles which are 
accidentally deposited on the conveyor flight 290 in a free condition may 
be moved upwardly in the chamber 214. Similarly, the operation of the 
projecting winnower 282 cooperating with shroud structure 412 is such that 
most of the remaining tobacco particles moving across the middle chamber 
214 will be received within the opening 278 with any others therebelow 
being handled by the operative conveyor flight 290. 
It will be seen that the objects of this invention have been fully and 
effectively accomplished. It will be realized that the foregoing preferred 
specific embodiment has been shown and described for the purpose of this 
invention and is subject to change without departure from such principles. 
This invention includes all modifications encompassed within the spirit 
and scope of the following claims.