US3491770A - Centrifugal tobacco stream forming apparatus - Google Patents

Description

' 27, 1970 w. RUDSZINAT' ET AL 3,491,770

CENTRIFUGAL TOBACCO STREAM FORMING APPARATUS Filed June 8, 1965 e sheets-Shea 1 Fig. 7

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CENT RIFUGAL TOBACCO STREAM FORMING APPARATUS Filed June 8, 1965 6 Sheets-Sheet 2 Fig. 3

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CENTRIFUGAL TOBACCO STREAM FORMING APPARATUS Filed June 8, 1965 6 Sheets-Sheet 5 Inventor-5 4 Eula/m1 [in [lu- Jan. 27, '1970 w. RubszmAT ETAL 3,491,770

CENTRIFUGAL TOBACCO STREAM FORMI NG APPARATUS Filed June 8, 1965 6 Sheets-Sheet 6 Fig. 6

In ven tors I'M/l Rum, 204i fl ialvr 4 United States Patent 3,491,770 CENTRIFUGAL TOBACCO STREAM FORMING APPARATUS Willy Rudszinat, Hamburg-Lohbrugge, and Giinter Wahle,

Hamburg-Bramfeld, Germany, assignors to Hanni- Werke Koerber & Co. K.G., Hamburg-Bergedorf, Germany Filed June 8, 1965, Ser. No. 462,216 Claims priority, application Germany, June 9, 1964, H 52,914, H 52,915; Apr. 9, 1965, H 55,750 The portion of the term of the patent subsequent to May 9, 1984, has been disclaimed Int. Cl. A24c 5/39 US. Cl. 131-84 15 Claims ABSTRACT OF THE DISCLOSURE Apparatus for producing a tobacco stream comprising a first conveyor which advances tobacco particles, a second conveyor which advances the stream, and a third conveyor which transfers the particles from the first to the second conveyor and simultaneously converts the particles into a stream and wherein the particles are propelled radially outwardly by a rotor which cooperates with a stator and is accommodated in a housing. A flow of air with the tobacco particles into the second conveyor is throttled and the apparatus further comprises a pneumatic system which assists the entry of the radially and fanwise propelled particles into an annular chamber in the housing wherein the particles form said stream which is thereupon expelled into the second conveyor.

The present invention relates to distributors for fibrous material in general, and more particularly to improvements in distributors of the type which may be utilized to form and deliver a stream of tobacco particles to the rod forming mechanism of a cigarette machine or the like. Still more particularly, the invention relates to improvements in distributors of the type which are particularly suited to form a stream of shredded tobacco and which can produce a tobacco stream that can be wrapped or otherwise processed without invariably necessitating a trimming operation.

The distributor of our present invention constitutes an improvement over and a further development of the distributors which are disclosed in our copending applications Ser. Nos. 414,044 and 424,376 respectively filed on Oct. 12, 1964 and Ian. 8, 1965. The application Ser. No. 414,044 matured into US. Patent No. 3,318,313 issued May 9, 1967. Application Ser. No. 424,376 is now abandoned.

Distributors of the type to which our present invention pertains are utilized to deliver streams of thoroughly intermixed tobacco particles to a cigarette, cigar or cigarillo machine and to form streams of constant or substantially constant cross section so that, if at all possible, the stream should be in a condition ready for wrapping without trimming, i.e., without bodily removal of tobacco particles or portions of tobacco particles from the continuous tobacco body which issues from the distributor.

Our aforementioned copending applications Ser. Nos. 414,044 and 424,376 disclose distributors wherein a mass of tobacco particles is subjected to the action of centrifu- I gal force to form a tobacco stream which accumulates in an annular space and is thereupon conveyed to the rod forming mechanism of a cigarette machine or the like. It was found that such centrifugal distributors can produce tobacco streams of highly satisfactory uniformity, even in the event that the particles which enter the distributor are not delivered at a constant rate. However, and due to the fact that many heretofore known centrifugal distributors act not unlike a centrifugal blower and are equipped with blades or vanes which propel the tobacco particles radially outwardly and into the annular stream forming space, the advance of particles through the distributor is too rapid so that a mass of particles which are delivered at irregular intervals or in the form of an irregular shower does not have sufficient time to be transformed into a stream of uniform cross section. The stream accumulates at one side of a sieve which allows air to pass there through whereby the stream is pressed against the sieve by a differential in pressures prevailing at the opposite sides of the sieve. It was found that, if air is admitted in large quantities, it causes excessive acceleration of tobacco particles so that the resulting stream is one of less than absolutely uniform consistency, particularly as regards its cross section but also as regards the intermixing of particles which form the stream.

Accordingly, it is an important object of the present invention to provide a centrifugal distributor wherein the flow of air is controlled in such a way that, While the current or currents of air are useful to assist in the formation of a satisfactory tobacco stream, such currents cannot bring about excessive acceleration of conveyed material and cannot affect but will actually enhance the uniformity of the ultimate product.

Another object of the invention is to provide a distributor of the just outlined characteristics wherein the current or currents of air will substantially prevent agglomeration of tobacco particles on their way to the stream accumulating space and wherein the rate of air flow may be controlled with precision, while the distributor is in use, and in a very simple and time-saving manner.

A further object of the present invention is to provide a distributor which may be readily combined or connected with one or more additional distributors to subject a mass of tobacco particles to a series of consecutive treatments with the result that the stream which leaves the last distributor is ready for immediate entry into the rod forming mechanism of a cigarette, cigar or cigarillo machine.

An additional object of the invention is to provide a closed pneumatic circuit which may be utilized in a distributor or in a series of distributors embodying the above outlined features and advantages.

A concomitant object of the invention is to provide a novel stream forming device which may be utilized in the improved distributor.

Still another object of the instant invention is to provide a novel air lock which prevents uncontrolled entry of air into the working chamber of the distributor.

Briefly stated, one feature of our invention resides in the provision of an apparatus for producing a uniform stream of tobacco particles. The apparatus constitutes a distributor and comprises a first conveyor which is arranged to advance the particles in a first path, a second conveyor which is arranged to advance the tobacco stream in a second path, and a third or stream forming conveyor which serves to transfer the particles from the first path into the second path and to simultaneously convert the particles into a stream. The third conveyor comprises a rotor member and an annular member which is coaxial with the rotor member. These two members are provided with adjacent but spaced end faces which define between themselves a radially outwardly extending working chamber or rotor chamber provided with an annular outlet at the periphery of the rotor member. The annular member has an axially extending inlet for admission of particles from the first path into the rotor chamber whereby such particles impinge against and are propelled by the rotor member toward and through the outlet. The third conveyor further comprises a housing defining an annular tobacco collecting and stream forming space which surrounds the outlet of the rotor chamber. The housing is provided with an aperture through which the particles can pass from the stream forming space on to the second path, and this housing is further provided with a first and second annular opening. The two openings are concentric with and communicate with the stream forming space radially outwardly of the outlet and the housing accommodates a rotary foraminous annulus or sieve which overlies the first opening. Finally, 'thethird conveyor comprises one or more blowers or analogous air circulating devices which are connected with the housing to send a current of air through at least one of the aforementioned openings and through the perforations of the annulus in a direction to assist the movement of particles from the outlet into the annular stream forming space whereby such particles accumulate and form on the annulus a stream which is evacuated through the aperture of the housing to enter the path defined by the second conveyor which may deliver the stream on to a rod forming and wrapping mechanism in a cigarette machine or to a second distributor.

Thus, the current of air which assists the advance of tobacco particles from the outlet into the annular stream forming space and which causes the resulting stream to adhere to the foraminous annulus need not pass through the working chamber of the third conveyor so that such air cannot bring about undue acceleration of tobacco particles. Any such air which is needed to prevent clogging of the working chamber may be admitted in controlled quantities through the inlet of the annular member.

The improved distributor itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a partly elevational and partly vertical sectional view of a distributor which is constructed and assembled in accordance with a first embodiment of our invention including a schematic diagram for the electrical components included therein and wherein the first conveyor receives shredded tobacco from a weighing device;

FIG. 2 is an enlarged sectional view of a detail in the distributor of FIG. 1;

FIG. 3 is a top plan view of the structure shown in FIG. 2;

FIGS. 4a and 4b together illustrate in axial section a duplex distributor which includes two serially connected centrifugal stream forming devices;

FIG. 5 is an enlarged fragmentary horizontal section substantially as seen in the direction of arrows from the line VV of FIG. 4a; and

FIG. 6 illustrates a modification of the structure shown in FIG. 5.

Referring first to FIG. 1, there is shown a distributor which comprises a first conveyor or supply conveyor A, a second or take-off conveyor B, and a third or transfer conveyor which serves to transfer particles of shredded tobacco from the conveyor A to the conveyor B. The distributor of FIG. 1 further includes a weighing device which feeds measured quantities of tobacco to the supply conveyor A. v

The weighing device comprises a weighing box 108 which receives tobacco particles from a hopper including an endless conveying belt 101 trained around rolls 102, 103 the first of which is driven to advance the upper stringer of the belt 101 in the direction indicated by an arrow 101a. The upper stringer of this belt supports a supply 104 of shredded tobacco and feeds such tobacco against the periphery of a carded combing roller 105 which rotates in a counterclockwise direction. The roller cooperates with a refuser here shown as a carded brushing roller 116 which removes surplus tobacco from the periphery of the roller 105 so that the layer 107 which advances beyond the lowermost point of the refuser 116 is of nearly constant thickness. Such layer is removed from the periphery of the roller 105 by a rapidly revolving carded picker roller 106 which is driven in a clockwise direction and transforms the layer 107' into a shower 107a which descends into the weighing box 108. The latter is mounted on the right-hand arm of a scale beam or balance beam 109 whichis fulcrumed at 109a. Suitable weights (not shown) are provided on the scale beam 109 to compensate for the mass of the empty weighing box, and the left-hand arm-of the beam 109 carries a platform 110 for a counterweight 1 11 which determines the exact quantity of particles that may accumulate in the weighing box 108. The free end portion 112 of the left-hand arm of. the scale beam 109 constitutes the moving contact of a'singl'e-pole electric switch whose fixed contact 113 is connected in the ci'rcuit'114 of a source 114a of electrical'energy; the switch 112, 113 is connected in series with an electric motor 115 which drives the rollers 105, 106, 116 in a manner clearly shown in FIG. 1. The motor 115 also drives the roll 102. The motor 115 is arrested as soon as the combined weight of tobacco particles in the weighing box 108 exceeds the weight of the counterweight 111, i.e., the switch 112, 113 opens to interrupt the flow of electric current in the circuit 114 when the box 108 accumulates a requisite quantity of tobaco particles such as will form a batch of predetermined weight. The bottom wall 117 of the weighing box 108 constitutes a gate which is hinged at 118 and which is allowed or caused to move to the phantomline position 117 as soon as the box 108 accumulates a full batch of tobacco particles. Such movements of the gate 117 are effected by an electrical control device 107 which sends an impulse when the switch 112, 113 is open, i.e., at intervals which are long enough to allow for accumulation of full batches. The box 108 then dumps its contents onto the upper stringer of an endless belt 123 which constitutes a component of the supply conveyor A and which advances the freshly vdumped batch in the direction indicated by an arow 123a. The gate 117 auto matically returns to the full-line position of FIG. 2 when the box 108 is empty. The control device 107 is actuated at regular intervals by an electrical impulse generating device 119.

If desired, the weighing device may further include an intercepting device serving to collect all such particles of tobacco which continue to descend toward the gate 117 due to inertia of the rollers 105, 106, 116 after the switch 112, 113 opens. A suitable intercepting device is disclosed in our copending application Ser. No. 372,964, filed June 5, 1964 and now abandoned. This application also describes the construction and operation of the devices 107 and 119. The gate 117 normally seals an elongated discharge opening in the bottom portion of the weighing box 108, and such discharge opening will allow the freshly accumulated batches to descend in such a way that the longitudinal extension of each batch is parallel with the direction indicated by the arrow 123a.

The weighing device also includes suitable stops 109b, 109a which limit oscillatory movements of the scale beam 109. The needles of the picker roller 106 extend into the spaces between the needles of the combing roller 105 to make sure that all tobacco particles which form the layer 107 actually descend into the box 108. The rotational speed of the picker roller 106 exceeds considerably the speed of the combing roller 105.

The belt 123 of the supply conveyor A is trained around the two idler rolls 120, 121 and around a driven roll 122. The roll 122 is rotated at a constant speed by a suitable motor, not shown. The batches on the upper stringer of the belt 123 form a carpet or mat 125 which advances in the direction indicated by the arrow 123a.

A sealing roller 124 is provided above the left-hand end turn of the belt 123 at a level slightly above the driven roll 122. This roller 124 comprises a mantle consisting of rubber or other suitable elastomeric material and cooperates with the roller 122, as well as with an 1nlet duct 126 shaped to prevent or to at least hlnder the entry of air into the upper end of the duct 126. The mounting of the sealing roller 124 is shown in FIGS. 2 and 3, and it will be seen that this roller is free to rotate about the axis of a transverse horizontal shaft 160 which is adjustable in arcuate slots 155, 158 respectively provided in two vertical side walls 156, 157. The side walls 156, 157 are connected to or integral with the duct 126, and the distance between their inner faces equals the width of of the belt 123. Two wing nuts 159, shown in FIG. 3, may be manipulated by the operator when it becomes necessary to change the position of the sealing roller 124 with reference to the upper stringer of the belt 123. The roller 124 will rotate in response to engagement with the upper side of the layer 125, and its mantle will compress the layer 125 to such an extent that the amount of air which penetrates into the duct 126 is negligible. The lower end portion of the duct 126 is of circular cross section but its upper end portion is curved as shown in FIG. 2 and its cross-sectional outline resembles a rectangle whose width is the same as the distance between the inner faces of the side walls 156, 157. The axial length of the sealing roller 124 also equals the distance between the inner faces of the side walls 156, 157 and the periphery of this roller slides along an elastically deformable sealing lip 161 which is provided at the upper end of the inlet duct 126. A second sealing lip 162 is provided at the top of the right-hand vertical wall of the inlet duct 126, as viewed in FIG. 2, and this second lip 162 is in sealing engagement with the lower stringer of the belt 123. A plate-like base 171 of metal or other rigid material is located at a level below the sealing roller 124 and serves as a supporting platform for the leftmost portion of the upper stringer of the belt 123. This base 171 extends all the way between the side walls 156, 157 and cooperates with the elastic mantle of the sealing roller 124 to prevent entry of air into the duct 126. The axial length of the idler roll 120 equals the axial length of the sealing roller 124, and the end faces of the parts 120, 124 are in sealing contact with the side walls 156, 157. The lateral edges of the belt 12 are also in sliding contact with the side walls 156, 157 and, on advancing beyond the left-hand end turn of the conveyor A, the carpet 125 of tobacco particles is transformed into a shower 125a which leaves the path defined by the upper stringer of the belt 123 and descends by gravity into a centrifugal stream forming device 170 shown in FIG. 1. During its passage through the horizontal slit or gap 163 between the elastic mantle of the sealing roller 124 and the upper stringer of the belt .123, the carpet 125 is compressed in a manner best shown in FIG. 2 and is then substantially free of air. Thus, the upper end of the inlet duct 126 is practicall sealed from the atmosphere, particularly if one disregards negligible amounts of air which will leak along the inner faces of the side walls 156, 157 and through the gap 163.

The inlet duct 126 is connected to the top wall of a stationary housing 127 which accommodates the aforementioned centrifugal stream forming device 170. As shown in FIG. 1, the top wall of the housing 127 is provided with a cutout which registers with the channel defined by the duct 126, and the latter comprises a lower end portion 126a which is accommodated in an uppermost compartment 142 of the housing 127. The lower end of the duct portion 126a is connected to or is integral with an annular member or stator 129 which forms part of the stream forming device 170. The portion 126a is an axially extending inlet for the shower 125a into a radially outwardly extending working chamber or rotor chamber 128 which is provided between the lower end face of the stator 129 and the upper end face of a rotor 130. The rotor is coaxial with the stator 129 and its upper end face is adjacent to but spaced from the lower end face of the stator so that the working chamber 128 extends toward and has an annular outlet 137 along the periphery of the rotor 130. The parts 129, 130 of the stream forming device 170 resemble disks and are provided with concentric corrugations which insure that the particles descending through the inlet duct 126 and impinging against the central zone of the upper end face on the rotor 130 must travel a considerable distance prior to reaching the outlet 137. Such particles will 'be propelled by centrifugal force to rebound on the corrugations of the stator 129 and to return into contact with the rotor 130. The same procedure is repeated once or more than once so that the duration of advance of any given particle from the inlet 126a to the outlet 137 is much longer than the interval necessary to simply propel the particle by centrifugal force. The common axis of the stator 129 and rotor 130 is indicated by a phantom line and is numbered 131. The cross section through the working chamber 128 is of zig-zag or meandering shape, and FIG. 1 shows that one can find a plane which is normal to the axis 131 and intersects each corrugation on the stator 129 and each corrugation on the rotor 130 so that each particle which reaches the upper end face of the rotor 130 is invariably compelled to rebound on the stator prior to reaching the outlet 137. The height of the working chamber 128, as viewed in FIG. 1, may but need not be constant and the outermost zone of this working chamber preferably resembles a rather narrow annular slit through which the particles must advance prior to issuing from the outlet 137.

The rotor 130 is driven by a vertical shaft 133 which is mounted in bearings 132 provided in the housing 127. The lower end portion of the rotor shaft 133 carries a pulley 134 which is driven by an endless V-belt 135. The belt 135 is trained around a second pulley which is mounted on the output shaft of a variable-speed reversible electric motor 136.

.FIG. 1 shows that the housing 127 comprises three stationary rings 141, 172, 173 which are concentric with the working chamber 128 and outlet 137. These rings define an annular tobacco collecting space 169 which surrounds the outlet 137 of the working chamber 128. The ring 141 is located at a level above the rings 172, 173 and defines with the peripheral portion of the stator 129 a first annular opening 174 whose internal diameter at least equals the maximum diameter of the outlet 137, Le, the opening 174 is concentric with and surrounds the working chamber 128. A narrower second annular opening 175 is provided between the periphery of the rotor 130 and the ring 173; this second opening 175 is located directly below the first opening 174 and is sealed therefrom and from the outlet 137 by the inner portion of a revolving foraminous annulus and sieve 140. The opening 175 extends between the ring 173 and the periphery of a revolving carrier 138 which drives and is connected with the nonperforated inner portion of the sieve 140. The perforated outer portion of the sieve overlies a third annular opening 176 which extends between the rings 172, 173 and provides a passage between the aforementioned compartment 142 and a second or median compartment 143 in the housing 127. The radial distance between the third annular opening 176 and the axis 131 of the stream forming device exceeds the distance between the axis 131 and the first opening 174.

The carrier 138 is journalled in a bearing 139 and its lower end portion carries a gear 166 which is driven by a further gear, not shown, so that it rotates at a speed which is preferably less than the speed of the rotor 130. The second gear is driven by a motor, not shown, or by a variable-speed transmission which may derive motion from the motor 136 for the rotor 130. The sieve 140 is located in a plane which is normal to the axis 131, and

this sieve slides along the rings 141, 172, 173. The radially inner portion of the sieve 140 is without perforations so that it seals the second opening 175 from the outlet 137, from the opening 174 and from the annular space 169; however, the radially outer portion of the sieve 140 is perforated all the way around so that air entering into the space 169 via first opening 174 can pass through the sieve and through the third opening 176 to enter the second compartment 143. The housing 127 defines a third or lowermost compartment 144 which is sealed from the compartment 143 and accommodates the gear 166 of the carrier 138. The bearing 132 for the rotor 130extends through a cutout in the bottom wall of the housing 127 so that the pulley 134 is accessible at all times. Aside from the aforementioned passage including the openings 174, 176 and the annular space 169, the compartments 142 and 143 are sealed from each other.

The conveyor B comprises a pneumatic discharge duct 146 which extends upwardly from the perforated portion of the sieve 140 but overlies only a relatively small frac- H tion of this sieve. A second duct 146a of the conveyor B is located at a level below the sieve -140 and registers with the discharge duct 146. The lower end of the duct 146a is connected to the pressure side of an air circulating blower 147 which sends a strong current of air upwardly through the duct 146a, through that portion of the sieve 140 which is momentarily located between the ducts 146, 146a, and upwardly through the discharge duct 146 to advance the tobacco stream 150 in the path defined by the conveyor B. The stream 150 is formed on the perforated portion of the sieve 140 and is assembled of such particles which travel beyond the outlet 137 of the working chamber 128 to accumulate in the annuar space 169. The lower end portion of the discharge duct 146 extends through the upper ring 141, and the upper end portion of the duct 146a extends through a portion of the annular opening 176 between the rings 172, 173.

The compartment 142 is connected to the pressure side of a second blower 149 which sends a current of air through a nipple 152 discharging into the compartment 142. The compartment 143 is connected with the suction side of the blower 149 through a second nipple 148. The nipples 148, 152 are secured to the housing 127. The arrows indicate in FIG. 1 the direction in which the air current flows through the nipple 152, through the compartment 142, through the first annular opening 174, through the space 169, through the perforated portion of the sieve 140 (excepting for that zone of the perforated portion which is momentarily located between the ducts 146, 146a of the conveyor B), through the third opening 176, through the compartment 143, through the nipple 148, and on to the suction side of the blower 149.

When the distributor of FIG. 1 is in use, the blowers 147, 149 are driven by their respective motors (not shown) and the motor 136 is in operation to drive the rotor 130. The gear 166 drives the carrier 138 and the sieve 140, and the roll 122 is driven to advance the upper stringer of the belt 123 in the direction indicated by the arrow 12311.

The box 108 of the weighing device discharges batches of accurately metered tobacco particles at regular intervals determined by the control device 107 and by the impulse generating device 119 so that the batches form a continuous or discontinuous carpet or mat 125 which advances toward the gap 163 between the belt 123 and the sealing roller -124 to enter the inlet duct 126 wherein it forms the shower 12511. The motor 136 drives the rotor 130 at a speed which is substantially higher than the speed of the carrier 138 and sieve 140. At this time, we prefer to drive the rotor 130 and the sieve 140 in the same direction. The blower 147 sends a relatively strong current of air which ascends through the duct 146a and thereupon penetrates through the perforated portion of the sieve -140 to enter the discharge duct 146. As explained above, the blower 149 produces a second current of air which is drawn from the median compartment 143 and is discharged into the upper compartment 142. The current entering the compartment 142 passes through the first opening 174 and thereupon flows radially outwardly to assist in the transfer of tobacco particles from the'outlet 137 of the working chamber 128 into the annular space 169. Such air then passes through the major part of the sieve 140 and through the third opening 176 prior to returning to the suction side of the blower 149; The current produced by the blower 149 traverses the entire perforated portion of the sieve 140 with the exception of that zone which happens to be located between the ducts 146, 146a of the conveyor 3. Y

The operation of the distributor shown inFIG. l" is as follows: I

The batches which are discharged by the weighing device 108 at regular intervals (i.eI, whenever the control device 107 causes the gate 117 to move to 'the' phantomline position 117' of FIG. 1) form the carpet which passes through the air lock defined by the side walls 156, 157, lips 161, 162, sealing roller 124, belt 123 and'the upper part of the inlet duct 126. Thus, the material which passes through the gap 163 is substantially free of air and is transformed into the shower 125a. The sealing roller 124 constitutes an adjustable valve member which will be shifted up or down if the counterweight 111 is replaced by a heavier or lighter weight. Also, the sealing roller 124 will be adjusted if the operator desires to admit some air intothe upper end of the inlet duct 126.

The particles which form the tobacco shower 125a impinge against the central portion of the rotor and are propelled by centrifugal force to travel radially outwardly and to rebound on the annular corrugations of the stator 129. The thus projected particles expand fanwise while moving through the working chamber 128 and toward its outlet 137. The duration of the interval required by a particle to move from the inlet duct 126 to the outlet -137 is not predictable with utmost accuracy because the length of such interval depends upon whether or not a given particle will strike against one 'or more corrugations of the stator 129 and also whether or not such given particle will be propelled by the rotor 130 only once, twice or more than twice. The tobacco stream 150 which accumulates on the perforated portion of the sieve will be more uniform if the particles'remain in the working chamber 128 for relatively long intervals of time because the equalizing action of the stream forming device 170 is then more pronounced than if the particles are allowed to advance directly from the central zone of the rotor 130 and into the outlet 137. As a rule, each particle will follow a zig-zag shaped or meandering course and the material issuing from the outlet 137 will be of substantially uniform consistency (i-.e'., the particles are thoroughly intermixed with each other prior to leaving the working chamber 128). Also, the cross-sectional area of the stream will increase gradually from a point immediately downstream of the ducts 146, 146a (as seen in the direction in which the sieve 140 rotates) to a point immediately ahead of that portion of the sieve 140 which is located between the ducts 146, 146a.

The particles which reach the outlet 137 are entrained by the current of air rushing from the compartment 142 through the first opening 174 and into the annular space 169. This current of air also causes the stream 150 to adhere to the upper side of the sieve 140 becauseithe air passes through the sieve,'through the third opening 176 and into the median compartment 143' which'latt'er constitutes a suction chamber in contrast to the compartment 142 which can be called a plenum chamber. The tobacco stream 150 rotates with and at the speed of the sieve 140 so that its leading end enters the space between the ducts 146, 146a and is evacuated by the strong air current rushing up the ducts 146, 146a from'the pressure side of the blower 147. The numeral 151 denotes in 1 an aperture or slot through which the tobacco stream 150 passes on its way into the zone between the ducts 146, 146a. The aperture 151 is provided in the upper ring 141. The air current which is produced by the blower 149 is not effective in the zone between the ducts 146, 146a because the aperture 151 is practically filled with tobacco particles. The directionin which the current produced by the blower 147 passes through the sieve 140 is counter to the direction in which the current produced by the blower 149 passes from the annular space 169, through the sieve 140, through the third opening 176 and into the compartment 143. The discharge duct 146 delivers a uniform stream of tobacco particles to a rod forming and wrapping device or to a second distributor.

By changing the position of the sealing roller 124, the operatormay adjust the length of intervals required by the particles to advance from the inlet duct 126 into the outlet 137 of .the working chamber 128. If the adjustments in admission of air into the working chamber 12.8.in response to changes in the position of the sealing roller 124 are insufficient, the distributor of FIG. 1 may be .provided with a second or auxiliary valve 153 (shown in FIG. 1 by phantom lines because it constitutes an optional feature of our invention). This valve 153 is provided in a pipe 164 which discharges into the inlet duct 126 in a zone above the top wall of the housing 127, and its position may be changed by an actuating member 165.

In FIG. 1, the valve 153 is a throttle valve and resembles a flap which controls the entry of air through the pipe 164- and into the inlet duct 126. If the operator decides to adjust the auxiliary valve 153 through the intermediary ofthe actuating member 165 and in such a way that the pipe 164 will deliver a predetermined quantity of air, such air is sucked into the working chamber 128 when the rotor 130 is driven by the motor 136. The thus admitted air mixes with the particles which form the shower 125a and advances with such particles to issue from the outlet 137 and to be mixed with the current of air flowing through the duct 146a and into the discharge duct 146 of the conveyor B. The intake end of the pipe 164 is open to the atmosphere. By adjusting the position of the sealing roller. 124 and/or thev position of the auxiliary valve 153, the operator may control the entry of air into the working chamber 128 with desired accuracy. For example, the operator may move the sealing roller 124 to its lower end position in which the gap 163 delivers no air whatever or only a quantity of air which is negligible,

and the operator thereupon actuates the member 165 to admit into the inlet duct 126 a very accurately metered quantity of air ina zone located downstream of the sealing roller 124 but upstream of the working chamber 128. In adjusting the position of the auxiliary valve 153, the operator can take into consideration such minimal quantities of air which might leak through the upper end of the inlet duct 126.

A very important advantageof controlled admission of air into the working chamber 128 is that such air, when fed in requisite amounts, prevents agglomeration of tobacco particles in the working chamber. As a rule, one will admit just a little more air than is absolutely necessary to make sure that the working chamber- 128 is not clogged. However, the quantity of air which is admitted through the upper end of the inlet duct 126 and/ or through the pipe 164 should not exceed a certain maximum limit because such air will accelerate the particles and will cause them to advance more rapidly toward the outlet 137 with a resultant reduction in the uniformity of the tobacco stream 150. The rate at which air is admitted at 163 and/or at 164 should remain within a rather narrow range to insure the formation of a uniform tobacco stream 150 and to simultaneously insure that the working chamber 128 is not clogged with tobacco particles. I

An important feature of our invention resides in the provision of the openings 174 and 176 which allow a current of air to flow through the sieve but prevent such current of air from flowing through the working chamber 128 wherein the air current could bring about excessive acceleration of fanwise advancing tobacco particles so that the stream forming device 170 would be unable to form a stream of requisite uniformity. The pressure of the air current flowing from the first opening 174 to the third opening 176 may be regulated in any known manner at the will of the operator so that the current passing through the sieve 140 will subject the stream 150 to requisite compression. The air pressure prevailing in the annular space 169 where the stream 150 is formed can be selected independently of the pressure which prevails in the working chamber 128 so that the quantity of air which is admitted through the gap 163 and/or through the pipe 164 is just sufficient to prevent agglomeration of tobacco particles in the working chamber 128 but will not unduly shorten the length of intervals required by tobacco particles to advance from the inlet duct 126 into the outlet 137. The current of air flowing through the sieve 140 will hold the stream 150 against the upper side of the sieve to the very point where the leading end of the stream 150 enters the aperture 151 to be entrained by the ascending air current which is produced by the blower 147.

Since the diameter of the third opening 176 exceeds the diameter of the first opening 174 (i.e., the opening 174 is surrounded by the opening 176), and since the particles issuing from the outlet 137 must move radially outwardly, the air current flowing through the opening 174 is deflected radially outwardly to enter the annular space 169 prior to passing through the perforated portion of the sieve 140 and into and through the opening 176. Once the particles reach the sieve 140, they remain in such positions because of centrifugal force and the pressure produced by air flowing from the opening 174 to the opening 176. The spreading or equalizing action of the stream forming device 170 is not destroyed by the current of air which flows from the compartment 142 into the compartment 143; on the contrary, the air entering at 174 will compel the particles to follow the directions which were determined by the steam forming device 170 so that such air merely entrains the particles in desired directions, i.e., in an optimum distribution to insure the formation of a uniform tobacco stream. The openings 174, 176 resemble annular slits and, save for the zone between the ducts 146, 146a of the take-off conveyor B, these openings form two continuous annuli all around the axis 131 of the stream forming device 170.

It will be readily understood that the mass of a shredded tobacco particle is relatively small and that such particles offer littl resistance to changes in direction which can be effected by an air stream. Thus, even a very weak current of air will sufilce to deflect particles of shredded tobacco from their respective paths and, in order to prevent such uncontrolled changes in direction, the blower 149 is preferably connected with the openings 174, 176 in the aforedescribed manner to insure that the current of air entering the housing at 152 and leaving at 148 follows a predetermined course which is selected with a view to avoid any uncontrolled deflection of tobacco particles. v

The particles which are stored on the upper stringer of the belt 101 shown in FIG. 1 constitute fully fermented tobacco which contains volatile ingredients. Such ingredients should not be allowed to leave the tobacco in an uncontrolled manner, and this is prevented, to a considerable degree, by the provision of the closed pneumatic circuit which includes the blower 149 and which .circulates the same current of air. Thus, air which circulates through the compartments 142, 143 and through the openings 174, 176 is rapidly saturated with volatile ingredients and is thereupon incapable of taking up additional volatile matter so that the tobacco which is fed through the inlet duct 126 subequent to such saturation will lose none, or only a negligible percentage, of its volatile ingredients. Of course, whenever speaking of a closed pneumatic circuit, we disregard such relatively small amounts of air which are admitted through the gap 163 and/ or through the pipe 164 (when the auxiliary valve 153 is open) as well as such negligible amounts of air which will enter or leave the housing 127 due to inevita'ble leaks. Thus, we disregard all such air whose total quantity is negligible when compared with the current of air which is circulated by the blower 149. However, it is noted that air which enters through the member 164 is entrapped with the tobacco particles and is later discharged with the stream through the duct 146. In the illustrated embodiment, the thickness of the stream 150 increases gradually in the same direction in which the sieve 140 rotates about the axis 131.

FIGS. 4a and 4b together illustrate a modified distri'butor wherein the stream forming conveyor which transfers tobacco particles from the path defined by a feed conveyor AA into the path defined by a take-oil conveyor BBB (see FIG. comprises two centrifugal stream forming devices 370 and 230 which are respectively shown in FIGS. 4b and 4a. The device 370 of FIG. 4b is substantially identical with the stream forming device 170 of FIG. 1 and many of its component parts are identified by reference numerals which, with the exception of the first digit (3) are identical with those used in FIG. 1. The endless belt 323 of the feed conveyor AA receives accurately metered batches of tobacco particles from a weighing device wihch includes a weighing box 308 having a pivotable gate 317 which is movable to and from the phantom-line discharging position 317'. The thus formed carpet 325 then advances through an air lock defined by the idler roll 320, by the sealing roller 324 and by the upper end portion of the inlet duct 326.

The distributor of FIGS. 4a and 4b comprises a single air circulating device in the form of a blower 180 whose pressure side is connected with a pressure conduit 181 leading to the nipple 352 of the stationary housing 327 and having a branch conduit 217 which delivers a current of compressed air into the duct 346a of a first take-01f conveyor BB. This conveyor BB constitutes the feed conveyor for the second stream forming device 230 and further includes a discharge duct 346 as well as an arcuate connecting or transfer duct 187 which latter is analogous to the inlet duct 326 and serves to feed a shower 350a of tobacco particles into the working chamber 195 of the stream forming device 230. The nipple 148 of FIG. 1 has been omitted, i.e., the median compartment 343 of the housing 327 is not directly connected to the suction side of the blower 180. Instead the compartment 343 communicates with a compartment 182 (see FIG. 4a) which is defined by the stationary housing 179 for the second centrifugal stream forming device 230. The pulley 334 at the lower end of the rotor shaft 333 is provided with two peripheral groves one of which receives a portion of the V-belt 335 (driven by the electric motor 336) and the other of which receives a portion of a second endless V-belt 183 which drives a pulley 184 at the lower end of a shaft 193a serving to drive the rotor 193 of the device 230. The duct 346a of the conveyor BB accommodates an adjustable valve 185 which regulates the pressure of air current flowing from the branch conduit 217 and into the discharge duct 346. Thus, the valve 185 is located upstream of that portion of the sieve 340 which extends between the ducts 346a, 346. The compartment 182 communicates with the suction side of the blower 180 so that the distributor of FIGS. 4a and 4b can be said to comprise a closed pneumatic circuit. The air current entering the uppermost compartment 342 of the housing 327 through the nipple 352 passes through the annular opening 374, through the annular space 369, through the perforated portion of the sieve 340, through the annular opening 376, through the compartments 343 and 182, and ultimately reaches a suction conduit 216 which leads to the suction side of the blower 180.

The arcuate transfer duct 187 of the conveyor BB discharges into an inlet duct 186 which is connected to or forms an integral part of a rotary annular member 189, the latter forming part of the second stream forming device 230. The housing 179 for the device 230 is integral with or is rigidly connected to the housing 327 of the first stream forming device 370. The common axis 188 of the annular member 189 and rotor 193 is indicated by phantom lines, and the annular member 189 is driven by a pulley 190 which is provided at the upper end of the inlet duct 186. The pulley 190 is driven by an endless V-belt 191 which receives motion from a variable-speed reversible electric motor 192.

The shaft 193a of the rotor 193 is mounted in bearings 194 and is driven by the aforementioned pulley 184. The working chamber 195 is defined by the adjacent but spaced end faces of the annular member 189 and rotor 193. The configuration of the working chamber 195 is similar to that of the working chamber 328 or 128 and the chamber 195 comprises an annular outlet 196 which is adjacent to the peripheries of the rotary parts 189', 193. The annular member 189 is located beneath an inverted cup-shaped cover or lid 197 which is stationary and can be said to constitute a component part of the housing 179. The marginal portion of the cover 197 extends close to but is not in direct contact with the peripheral portion of the annular member 189. The housing 179 further comprises a fixed guide ring 198 which surrounds the parts 189, 193, 197 and defines with the cover 197 an annular opening 199 which, to a certain degree, is analogous to the annular opening 174 or 374. The rotor 193 is located above a second stationary ring 200 of the housing 179, and the peripheral surface of the ring 200 bounds the inner side of the lower portion of the annular opening 199. The annular inlet of the opening 199 is shown at 218, and this opening communicates with a second annular opening 219 which surrounds a rotary carrier 202 for a sieve 201. A portion of the opening 219 is closed by a plate-like insert 214 shown in the left-hand part of FIG. 4a. The outlet 196 of the working chamber 195 is located at a level substantially midway between the annular inlet 218 of the opening 199 and the sieve 201, and this outlet 196 communicates with the opening 199 so that the particles of tobacco which leave the Working chamber 195 may be entrained by the current of air which enters at 218 and are deposited on the upper side of the sieve 201. The sieve 201 overlies the opening 219 and its carrier 202 is mounted in bearings 203. The means for rotating the carrier 202 comprises a gear 20211 which is mounted in the lowermost compartment 213 of the housing 179. The axis 188 is common to the annular member 189, to the rotor 193 and to the carrier 202.

The ring 200 of the housing 179' supports the shaft 204a of a roller 204 (see also FIG. 5). The shaft 204a is parallel to the axis 188, and the roller 204 forms part of the take-off conveyor BBB. An endless belt 205 is trained around the roller 204 and around a second roller 208. Rollers 206, 207 are provided to tension the belt 205, and the lefthand stringer of this belt (as viewed in FIG. 5) extends tangentially of the annular opening 199 to direct the tobacco stream into a straight path leading to a rod forming and wrapping mechanism or, if necessary, to a further distributor. The lower edge of the belt 205 is located directly above the sieve 201. The conveyor BBB comprises a second endless belt 210 which is trained around rollers 211 one of which is shown in FIG. 5. The upper stringer of the belt 210 is located in a horizontal plane and directly below the belt 205. The belts 205, 210 are driven at the same speed and in directions respectively indicated by the arrows 205a, 2100. The speed of the belts 205, 210 is the same as that of the sieve 201; therefore, the drive which rotates the gear 202a of the carrier 202 may be directly coupled to the rollers for the belts 205, 210.

In addition to the aforementioned compartments 182, 213, the housing 179 for the second stream forming device 230 defines a third compartment 212 which communicates with the opening 199 via sieve 201 and opening 219. The compartment 182 communicates with the inlet 218 of the opening 199, and the compartment 212 discharges into a duct 215 which is connected with the suction conduit 216 leading to the suction side of the blower 180. The compartment 213 accommodates the gear 202a of the carrier When the distributor of FIGS. 4a and 4b is put to use, the structure shown in FIG. 4b is operated in the same way as described in connection with FIG. 1. The belt 183 then drives the pulley184 of the rotor 193 in the second stream forming device 230. The gear 202a of the carrier 202 is driven ataspeed-which exceeds the speed of the gear 366 for the carrier 338, i.-e-., the r.p.m. of the sieve 201 in the stream forming device 230 exceeds the r.p.m. of the sieve 340. Themotor 192 drives the pulley 190 of the annular member 189, preferably in the same direction as that of the rotor 193 andcarrier 202. However, it is possible to drive. the annular member 189 and the rotor 193 in such a way that they-rotate in opposite directions.

The blower 180 is in operation and the belts 205, 210 are driven to advance in the. directions indicated by the arrows 205a, 210a.

The operation of the distributor shown in FIGS. 4a, 4b and is asfollows:

The streamforming. device 370 of FIG. 4b produces a first tobacco stream 350 which is discharged through the aperture 351 and enters'the zone between the ducts 346a, 346 of the take-off conveyor BB. This stream 350 is of very satisfactory uniformity and consists of thoroughly intermixed tobacco particles. In order to further improve the uniformity ofthis stream,--the. shower 350a shown in the discharge, duct 346 is conveyed through the arcuate 'transfer duct :187 whose; outlet forms the frustum of a hollow cone andextends into the inlet duct 186 of the annularmember 189 forming-part of the second stream forming device 230. The particles which form the shower 350a impinge against the central .zone of the rotor 193 and are propelled radially outwardly in the same way as described in connection with therotor 130. The resulting fanwisediverging body of tobacco particles passes through the annular outlet 196 of the working chamber 195 and is entrained by the air current which flows from the inlet 218 toward the annular space formed by the lower part of the annular opening .199 just above the sieve 201. The uniformityof the tobacco stream 400 which accumulates on the sieve. 201 exceeds the uniformity of the stream 350 due to the fact that the stream forming device 230 brings about a further equalizing action to insure that the cross-sectional area of the stream 400 increases gradually from a zone, just downstream of the insert 214 (as seen in the direction in which the sieve 201 rotates) to ,a zone just ahead of the roller 204 for the belt 205 ,ofthe take-01f conveyor BBB. The leading end of the stream,400 is notpressed against the upper side 'of the sieve 201: because the insert 214 seals the adjoining portions of the, openings 199 and 219' from each other so that the..belt 205 canreadily strip the tobacco .stream 400 off the, upper side of thesieve 201 and directs the stream ontothe upper, stringer of the belt 210 whereby the stream 400 leaves the housing 179 in the direction indicated by the arrow 210a (FIG. 5

The distributor of FIGS. 4a 4b and 5 comprises a single blower 180 and the single air current produced by in FIG. 4b) in response to partial or full opening of the auxiliary valve 353. The sealing roller 324 may be mounted in the same way as shown in FIGS. 2 and 3.

The valve in the duct 346a will be adjusted when the operator desires to regulate the pressure of the ascending air current independently of the current which flows in the compartments 342, 343 of the housing 327. The reason for preferably placing the valve 185 into the duct 346a, ratherthan into the duct 346 or 187, is that tobacco particles which form the shower 350a cannot interfere with adjustments and operation of the valve 185.

A second valve 185a is provided in the nipple 352 to regulate the flow of air from the pressure conduit 181 to the compartment 342. This second valve can be installed in the conduit 181. A further valve may be provided in the duct 215 or in the conduit 216.

Due to the fact that the sieve 140, 340 and/or 201 can rotate independently of the rotor 130, 330 or 193, the r.p.m. of the rotor (and hence the length of intervals during Which the particles of shredded tobacco remain in the respective working chambers 128, 328, may be selected independently of the r.p.m. of the carriers 138, 338, 202. Since the length of the just mentioned intervals will determine the uniformity of the stream 150, 350 or 400, such uniformity may be regulated by changing the rotational speed of the motor 136 or 336 and/or by changing the r.p.m. of the corresponding carrier. The sieve in each stream forming device of our invention is functionally independent of the corresponding rotor so that their rotational speeds may be selected independently of each other. As a rule, the r.p.m., of the sieve will be much less than the r.p.m. of the rotor, and the r.p.m. of the sieve can correspond to the forward speed of the tobacco stream which issues from the respective annular space. In many conventional centrifugal distributors of which we have knowledge at this time, the sieve covers the annular outlet of the working chamber and rotates at the exact speed of the rotor. In our improved distributor, the rotor revolves at a high speed to improve the uniformity of the tobacco stream, and the sieve rotates at a speed which may be substantially less than that of the rotor to insure that the tobacco stream is built up to a desired cross section and is transported away at a speed which is required for further processing in a rod forming mechanism or in the next distributor.

When the distributor comprises two or more serially connected stream forming devices, the sieve of the preceding stream forming device is preferably driven at a speed which is less than the speed of the sieve in the next-following stream forming device. Thus, and referring to FIGS. 4a and 4b, the r.p.m. of the sieve 340 in the first stream forming device 370 is preferably less than the r.p.m. of the sieve 201 in the stream forming device 230. The distributor of FIGS. 4a and 4b requires three air currents, namely, the current which flows from the opening 374 to the opening 376 of the first stream forming device 370, the current which flows from the opening 199 to the opening 219 of the second stream forming device 230, and the current which advances the shower 350a in the path defined by the pneumatic takeotf conveyor BB. The first two currents respectively issue from and enter the pressure and suctionsides of the blower 180; the amount of air in each of these first two currents is substantially the same. The pneumatic conveyor BB is connected in parallel with the conveyor system which includes the conduit 181 and housing 327 because its air requirements need not be the same as the requirements of the conveyors which conduct the air currents passing through the stream forming devices 370 and 230.

The reason that the particles entering the Working chambers 128, 328, 195 are likely to agglomerate if the respective inlet ducts do not admit any air is that the corrugations of the rotor and the corrugations of the associated annular member 129, 329 or 189 produce relatively stationary turbulences in the form of eddy currents which prevent further advance of tobacco particles toward the respective outlets. It can also happen that such eddy currents accumulate coherent particles of tobacco which form plugs or the like and which adhere to each other during movement toward the respective outlet. This means that the stream 150, 350 or 400 could contain plugs of strongly cohering tobacco particles which is highly undesirable for obvious reasons. The air which is admitted to the rotor chambers at 163 and/or 164, adjacent to 324 and/or at 364, and at 187 is subjected to the action of centrifugal force and invariably prevents the formation of agglomerations or plugs which could have an adverse effect on the uniformity of tobacco streams. The percentage of air which is admitted into the working chambers will depend on the dimensions of the distributor, on the rotational speed of the rotor, on the rotational speed of the annular member 186, on the cross-sectional area of the working chamber, on the rate at Which the tobacco showers are fed to the respective working chambers, and on certain other factors.

Experiments have shown that the quantity of air admitted into a working chamber should not exceed the quantity of air which is contained in a loose tobacco stream or carpet containing the same quantity of tobacco particles as the quantity contained in the working chamber at any given moment when the stream forming device is in use. Thus, if the sealing roller 124 shown in FIGS. 2 and 3 prevents entry of any air through the gap 163, the pipe 164 at the very most admits as much air as would be contained in the carpet 125 if this carpet were transformed into a freely flowing stream of uncompressed tobacco particles. The provision of the pipe 164 and auxiliary valve 153 is of advantage because they allow for more uniform admission of air than by allowing air to pass through the gap 163. The same holds true for the pipe 364 and auxiliary valve 153 of FIG. 4b.

The distributor of FIGS. 1-3 or FIGS. 4a-5 may be modified in a number of ways without departing from the spirit of our invention. For example, and referring to FIG. 1, the feed conveyor A may deliver tobacco to two or more stream forming devices 170 which, contrary to the showing of FIGS. 4a and 4!), may be connected in parallel rather than in series. Also, each of a series of separate stream forming devices 170 may receive batches of tobacco particles from a separate feed conveyor A. All such devices 170 may be mounted to feed tobacco streams to a common distributor which may include a stream forming device 370 and/or 230. In such constructions, the connection between two or more stream forming devices 170 and the next-following stream forming device or devices preferably comprises switchover devices which may be actuated to selectively feed tobacco streams from any one of the devices 170. Such switchover devices are disclosed in our aforementioned copending application Ser. No. 424,376. Thus, the nextfollowing stream forming device may receive tobacco from one device 170 at a time.

For example, and referring to FIGS. 41: and 4b, the distributor therein shown could comprise two or more stream forming devices 370 (FIG. 4b) and a single stream forming device 230 (FIG. 4a). The aforementioned switchover device may comprise a device which selectively connects the branch conduit 217 to one of the devices 370 so that the inlet duct 186 of the rotary annular member 189 in the stream forming 'device 230 may receive a tobacco shower 350a from the take-off conveyor BB of a selected device 370. While a device 370 discharges the freshly formed tobacco stream 350 into the working chamber 195 of the device 230, the remaining device or devices 370 will build up their streams 350 to discharge such streams into the working chamber 195 in response to connection of the branch conduit 217 to the respective conveyor BB. The tobacco stream 400 in the space defined by the lower portion of the annular opening 199 in the stream forming device 230 may consist of several en'd-to-end arranged sections formed by showers 350a which are delivered, alternatively or seriatim, from two or more stream forming devices 370. Each device 370 which is not connected to the branch conduit 217 builds up a tobacco stream 350 of requisite cross-sectional area and discharges the stream as soon as its conveyor BB is connected with the pressure side of the blower 180. By providing suitable control units which insure that the branch conduit 217 is connected to consecutive stream forming devices 370 at requisite intervals, the showers 350a will form a continuous stream 400 of great uniformity despite the fact that such showers come from two or more separate devices 370, i.e., the serially delivered showers 350a will form a continuous shower which enters the working chamber 195 of the device 230 and is transformed into a continuous tobacco stream 400. The just described mode of operation is of particular advantage when the devices 370 require relatively long intervals of time in order to build up tobacco streams 350 of requisite crosssectional area and when the device 230 can transform the showers 350a into a continuous stream 400' Within periods of time which are shorter than the intervals necessary to build up a stream 350. Thus, the length of intervals required by a tobacco particle to advance from the inlet duct 126 or 326 to the annular space 169 or 369 may be varied by changing the rate at which the inlet duct 126 or 326 receives air, and the uniformity of the tobacco stream or 350' improves if the length of such intervals is increased without, however, allowing for agglomeration of particles in the working chamber 128 or 328. On the other hand, and since the working chamber 195 of the device 230 shown in FIG. 4a receives tobacco showers 150a or 350a which are formed by substantially uniform tobacco streams 150 or 350, the interval required by a particle to advance from the inlet duct 186 to the annular opening 199 may be relatively short so that the device 230 may process tobacco received from two or more devices or 370.

For example, the control unit which will connect the branch conduit 217 to the duct 346a of a selected conveyor BB may be synchronized with the rotary carriers 338 of the primary stream forming devices 170 or 370 so that each device 170 or 370 will remain connected to the branch conduit 217 for an interval of time which is required by the respective carrier 138 or 338 to complete a full revolution, i.e., to discharge a complete tobacco stream 150 or 350. The exact construction of the just mentioned control unit forms no part of the present invention and, therefore, this unit is not shown in the drawings.

In the distributor of FIGS. 4a, 4b and 5, the transfer of the shower 350a from the sieve 340 into the working chamber 195 takes place by resorting to a pneumatic conveyor BB. The conveyor BBB which receives tobacco from the space above the sieve 201 is of the mechanical type. FIG. 6 illustrates a pneumatic take-off conveyor BBB which is analogous to the conveyor BBB and which defines a path for receiving a tobacco stream for the annular space above a revolving sieve 401 corresponding to the sieve 201 of FIG. 4a. The belts 205, 210 of the conveyor BBB are replaced by a suction pipe 402 which conveys the tobacco stream (corresponding to the stream 400 shown in FIG. 4a) in the direction indicated by an arrow 405. The path defined by the pipe 402 is tangential to the perforated portion of the sieve 401. The insert 414 corresponds to the insert 214 and serves to prevent the air current produced by the blower (not shown in FIG. 6) from interfering with the air current which propels the tobacco stream into the pipe 402. The pipe 402 leads to a separator 403 which is connected to the suction side of a blower 404 serving to evacuate air from the 17 tobacco stream which then advances in the direction indicated by the arrow 405.

An important advantage of the conveyor BBB shown in FIG. 6 is that it allows for a simplified construction of the stream forming device 430 which includes the sieve 401. Thus, the rings of this device 430 need not be provided with cutouts such as the cutouts which accommodate the parts of the mechanical conveyor BBB. Consequently, the danger that some air would leak into or from the stream forming device 430 is practically nonexistent.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an apparatus for producing a stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path, comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet, said housing having an aperture through which the particles can pass from said annular space on to said second path and having a pair of concentric annular openings communicating with said annular space radially outwardly of said outlet, and air circulating means connected with said housing for sending a current of air through at least one of said annular openings in a direction to assist the movement of particles from said outlet into said annular space.

2. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for tranferring the particles from said first path into said second path and for simultaneously converting the particles into a stream, said third conveyor comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotary foraminous annulus overlying said first opening, and air circulating means connected with said housing for sending a current of air through at least one of said openings and through said annulus in a direction to assist the movement of particles from said outlet into said annular space whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture.

3. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path and for simultaneously converting the particles into a stream, said third conveyor comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotary foraminous annulus overlying said first opening, and air circulating means having a suction side communicating with said first opening and a pressure side communicating with said second opening for sending a current of air through said openings and through said annulus in a direction to assist the movement of particles from said outlet into said annular space whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture.

4. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path and for simultaneously converting the particles into a stream, said third conveyor comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotary foraminous annulus overlying said first opening, and a closed pneumatic circuit including air circulating means having a suction side communicating with said first opening and a pressure side communicating with said second opening for sending a current of air through said openings and through said annulus in a direction to assist the movement of particles from said outlet into said annular space whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture.

5. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path and for simultaneously converting the particles into a stream, said third conveyor comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotary foraminous annulus overlying said first opening, said second conveyor comprising a pair of registering ducts disposed at the opposite sides of said annulus adjacent to said aperture, and air circulating means comprising a single blower arranged to send a first air current through said second opening, into said annular space, through said annulus and through said first opening so as to assist the movement of particles from said outlet into said annular space Whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture and whose leading end enters between said ducts, said blower being further arranged to send a second air current through said ducts and to thereby advance the leading end of said tobacco stream through one of said ducts.

6. A structure as set forth in claim 5, further comprising adjustable valve means for regulating the flow of said second air current through said ducts.

7. A structure as set forth in claim 6, wherein said valve means is providedv in the other of said ducts.

8. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path and for simultaneously converting such particles into a stream, said third conveyor comprising a stream forming device including a generally circular rotor member and a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, an air lock provided between said first path and said inlet to prevent uncontrolled entry of air into said working chamber, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotory foraminous annulus overlying said first opening, and air circulating means connected with said housing for sending a current of air through said openings and through said annulus in a direction to assist the movement of particles from said outlet into said annular space whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture.

9. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path and for simultaneously converting such particles into a stream, said third conveyor comprising a stream forming device including a generally circular rotor member and a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet duct for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, an air lock provided between said first path and said inlet duct to prevent uncontrolled entry of air into said working chamber, said air lock comprising an adjustable sealing member defining with said first conveyor a gap of variable cross-sectional area through which the particles enter said inlet duct, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotary foraminous annulus overlying said first opening, and air circulating means connected with said housing for sending a current of air through said openings and through said annulus in a diretcion to assist the movement of particles from said outlet into said annular space whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture.

10. In an apparatus for producing a uniform stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path and for simultaneously converting such particles into a stream, said third conveyor comprising a stream forming device including a generally circular rotor member and a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having axially extending inlet means for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, an air lock provided between said first path and said inlet to prevent uncontrolled entry of air into said working chamber, air admitting pipe means communicatively connected with said inlet between said air lock and said working chamber, adjustable valve means provided in said pipe means for regulating the admission of air into said inlet means, a housing defining an annular space surrounding said outlet and having an aperture through which the particles can pass from said annular space into said second path, said housing further having a first and a second annular opening, said openings being concentric and communicating with said annular space radially outwardly of said outlet, a rotary foraminous annulus overlying said first opening, and air circulating means connected with said housing for sending a current of air through said openings and through said annulus in a direction to assist the movement of particles from said outlet into said annular space whereby such particles accumulate and form on said annulus a stream which is evacuated through said aperture.

11. A structure as set forth in claim 10, wherein said pipe means is arranged to admit to said inlet such quantities of air which prevent agglomeration of particles in said working chamber.

12. In an apparatus for producing a stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path, comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber of meandering cross-sectional area and provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member fanwise toward said outlet to rebound on said annular member prior to reaching said outlet, a housing defining an annular space surrounding said outlet, said housing having an aperture through which the particles can pass from said annular space on to said second path and a pair of concentric annular openings communicating with said annular space radially outwardly of said outlet, and air circulating means connected with said housing for sending a current of air through at least one of said annular openings in a direction to assist the movement of particles from said outlet into said annular space.

13. In an apparatus for producing a stream of tobacco particles, a first conveyor for advancing the particles in a first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path, comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet, said housing having an aperture through which the particles can pass from said annular space into said second path and a pair of concentric annular openings communicating with said annular space radially outwardly of said outlet, and air circulating means connected with said housing for sending a current of air through at least one of said annular openings in a direction to assist the movement of particles from said outlet into said annular space and in such a way that said current bypasses said working chamber.

14. A structure as set forth in claim 13, further comprising means for admitting controlled quantities of air into said inlet to substantially prevent agglomeration of particles in said working chamber.

15. In an apparatus for producing a stream of tobacco particles, a first conveyor for advancing the particles in a first path; means for delivering batches containing metered quantities of tobacco particles into said first path; a second conveyor for advancing the stream in a second path; and a third conveyor for transferring the particles from said first path into said second path, comprising a generally circular rotor member, a centrally apertured member coaxial with said rotor member, said members having adjacent but spaced end faces defining between themselves a radially outwardly extending working chamber provided with an annular outlet at the periphery of said rotor member, one of said members having an axially extending inlet for admission of particles from said first path into said working chamber whereby such particles impinge against and are propelled by said rotor member toward and through said outlet, a housing defining an annular space surrounding said outlet, said housing having an aperture through which the particles can pass from said annular space on to said second path and a pair of concentric annular openings communicating with said annular space radially outwardly of said outlet, and air circulating means connected with said housing for sending a current of air through at least one of said annular openings in a direction to assist the movement of particles from said outlet into said annular space.

References Cited UNITED STATES PATENTS 1,772,715 8/1930 Grupe. 1,952,336 3/ 1934 Schneider. 2,367,911 1/1945 Wells. 2,629,385 2/ 1953 Kochalski 131-66 XR 2,629,386 2/ 1953 Kochalski. 3,034,514 5/1962 Pinkham. 3,096,770 7/1963 Dearsley 131-110 XR FOREIGN PATENTS 184,314 4/ 1907 Germany.

JOSEPH R. REICH, Primary Examiner US. Cl. X.R. 13122,

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