US2988213A - Tobacco separating apparatus - Google Patents

Description

June 13, 1961 w. A. DAVIS ETAL TOBACCO SEPARATING APPARATUS Filed Nov. 19, 1956 INVENTOR WADE A. DAVIS OSWALD ERICH ESSMANN BY BENJAMIN P. TSON 7 ATTORNEY United States Patent 2,988,213 TOBACCO SEPARATING APPARATUS Wade A. Davis, Oswald E. Eissmann, and Benjamin P.

Watson, Richmond, Va., assignors to American Machine and Foundry Company, a corporation Filed Nov. 19, 1956, Ser. No. 623,123 18 Claims. (Cl. 203-21) The present invention relates to a separating device for tobacco for separating torn tobacco leaf lamina from stems.

Heretofore, in separating devices, the torn tobacco struck or traveled along screens which acted as barriers or guiding means to take the tobacco out of the air stream while the air together with the dust and sometimes sand goes through the screens.

While these interposed screens acted as a guiding means to take tobacco out of the air stream, they also by their washboard-like action mutilate the tobacco, resulting in objectionable breakage and low yield. The tobacco conveyed by the air stream, either blown or sucked, hits these screens and due to the impact-small pieces of tobacco break 01f. The very small pieces broken off go through the opening of the screens and become tobacco dust not usable for manufacturing purposes. The larger ones which do not go through the screens go with the remainder of the leaf but will become still smaller during the process of manufacturing cigarettes and are then sifted out and so still lower the yield. In some devices the tobacco does not hit the screen by full force but only by its own momentum and then rubs along these wire screens. In that case the same action takes place, except the damage is not as great, but still objectionable. Sometimes the tobacco traveling along these screens catches itself in the screen openings and hangs there until it dries out,

then breaks off. During that stage, some parts of these leaf pieces will convert into dust and thereby also lower the yield.

T he existing separating means for tobacco also remove to a certain extent sand and dust hanging on the tobacco but do not remove it all. This is mostly due to the fact that after the batch of tobacco lamina once comes in contact with the screen, it remains flat on that screen subject to rubbing action along that screen, removing some said and dust from only that one side of the layer of tobacco lamina which is next to the screen. While the sand and dust on and between the other layers of tobacco lamina will remain, which of course is objectionable but heretofore could not be overcome.

All air separators known also remove and collect some of the lint in the tobacco, but not all. Some of that lint will collect on the screens, some will go through the screens and will be collected with the dust and still some lint, even if it is a small portion only, will go with the clean air and is discharged out of the fans either outside of the building or back in the workroom where it can be found-which is objectionable.

The present invention overcomes these three objections found in conventional separating means:

It gives higher yields since the tobacco does not hit against nor rub along screens which break off small tobacco pieces and convert them into dust.

It removes more of the free sand and dust from the tobacco as the tobacco is being subjected to a washing action in a turbulent air stream without rubbing against any surfaces.

It collects more lint by utilizing the circular motion of the air before it enters the fan as a centrifugal lint extractor.

Other objects aud features of the invention will appear as the description of the particular physical embodiment selected to illustrate the invention progresses. In the Patented June 13, 1961 accompanying drawings, which form a part of this speci fication, like characters of reference have been applied to corresponding parts throughout the several views which make up the drawings.

FIG. 1 is a cross-sectional side view of our improved separating apparatus.

FIG. 2 is a cross-sectional view taken through the two fanGs and the lint-collecting chamber on line 2-2 of PI 1.

In FIGURE 1, a conveyor belt 1 moves a mixture of tobacco flakes and stems to be separated into the separating channel 3. Stems fall out through outlet 5 against an air stream entering the separator through outlet 5 in the direction of the arrows 7.

The air flow is created by two fans 63 and and controlled by adjustment means 66 receiving an auxiliary supply of air through wire cloth covered air intakes 68. The lighter stem-free tobacco pieces together with some pieces of leaf containing stem travel upwardly through channel 9 into the expansion chamber 11. In expansion chamber 11 a separation takes place between the stemfree tobacco flakes and the flakes with adhering stems. The stem-free flakes keep on traveling through channel 13 while the flakes with adhering stems, after passing over wall 15, fall back through channel 17 against an auxiliary adjustable air stream of variable velocity across the width, entering through opening 19. That air stream separates stem-free tobacco pieces which might be thrown over wall 15 together with the tobacco pieces containing small portions of stems and takes them upwardly into channel 13 while the tobacco pieces with stems re-circulate and are ultimately discharged along the side walls of outlet 5 where they fall together with stems on the conveyor belt 21 for re-processing.

The stem-free tobacco pieces in channel 13 are conveyed by suction air into discharge chamber 38 around a reverse bend. Discharge chamber 38 consists of a curved solid wall 25 forming the outer wall of the reverse bend, tear-drop shaped guide 27 forming the inner wall of the reverse bend, a curved wall 23 and a curved wall 29. The tear shaped guide 27 and curved wall 29 fiorm an orifice 31.

The lowermost end of curved wall 29 terminates and forms one wall of an auxiliary air-sealing door 32. The tobacco sucked into separating housing 38 travels along the solid curved wall 25 by its own momentum and stays close to that wall by centrifugal forces exercised on the tobacco by the air stream which due to the fact of being sucked travels the short Way around the tear-drop shaped guide 27 and enters through orifice 31, the dust -air-collect ing chamber 33.

The separation of the tobacco from the air stream actually takes place in a vortex 35 which is created by having the air on one side, the short side of the tear.- drop shaped guide 27 while the tobacco by centrifugal force and its own momentum is on the other side, the long side, against a curved solid wall 25.

When the air enters through orifice 31, a negative pressure lifts the tobacco from the curved solid wall 25 approximately in the area indicated by 347. Then the tobacco whirls free in space 38 until it settles down and is discharged through airssealing outlet apparatus 39. The light tobacco lifted off the solid curved wall 25 in the area marked 37 leaves the heavy sand and dust on that wall, where it keeps on traveling by its own momentum until it reaches the sand screen area 41 through which it is discharged and by means of a worm-screw 43 removed out of the machine. Air-sealing outlet door 39, due to the fact that it turns, will continuously bleed a pre-determined small amount of air into the unit. That small amount of air, being sucked upwardly through orifice 31, creates a turbulence in the space 38 whichkeeps the tobacco pieces in a motion until they are finally discharged. This motion and the touching of the tobacco pieces with each other creates a certain cleaning effect, freeing the tobacco pieces from still-adhering dust and sand.

Y The sand will fall through the sand screen 41 and the dust will go with that air through orifice 31. At the same time small tobacco pieces, if they come close to the area, surrounding orifice 31, are picked up by the air stream and conveyed into the air collecting chamber 33. In order to avoid the collection of these small pieces in that area, auxiliary revolving door 32 is applied which discharges them directly into the outlet revolving door 39 where they are discharged and blended in with the rest ofthe tobacco.

Dust is removed from the air stream by a bank of cyclone filters 57. This dust separating section of the machine consists of four separate and distinct sections an air-collecting chamber 33, an air-distribution chamber 47, a dust-discharge chamber 49, and a clean-air chamber 51. Between the air-collecting chamber 33 and the air-distribution chamber 47 a fine mesh wire screen 53 is inserted, which acts as a resistor, distributing the air uniformly over the entire area. Any fine sand and coarse dust which might go through the screen 53 will settle down in the area 47 with wormscrew 55 on its lowermost part moving that portion of sand and dust out of the machine. The wire mesh screen 53 also acts as a lint catcher. Some of the lint will stick to that screen from which {it can be removed manually through suitable openings (not shown) in the outside walls of the machine.

The dust-loaded air together with lint which it still contains enters then, uniformly distributed into the intake ducts of a plurality of small cyclones 57. These cyclones separate the tobacco dust and some lint by centrifugal action and discharge the dust into chamber 49 which is located opposite the dust air entrance. Chamber 49 carries. in its bottom a worm-screw 59 moving that portion of dust and its lint out of the machine. The substantially clean air from the dust cyclones 57 is sucked through channel 51 into space 61 between the two fans '63 and 65. (FIG. 2.)

While cyclones 57 are very efiicient there are still traces of dust in that air together with a very small amount of lint not caught or separated elsewhere in the machine. That very small amount of dust and lint in the so-called clean air is in there due to the fact that the dust worm 59 is discharging its dust through an air-sealing revolving door similar to those shown for tobacco by reference characters 32 and 39, except much smaller. That small air-sealing revolving door attached to dust worm 59 lets enough air bleed in, which while being sucked upward through cyclones 57 takes sufficient fine dust with it, to leave a detectable trace of dust and lint in the clean air.

Since small diameter centrifugal cyclones operate with a separating efiiciency of 99% plus, the small portion of dust picked up by the air entering through the air-sealing revolving dust-disch-arger door is accepted by the industry as an objectionable necessity and in most cases, that air containing that small portion of dust is even fed back into the workroom.

In the present invention, however, we accomplished the removal of the greater portion of the dust and lint remaining in that so called clean air stream by a unique arrangement of two fans and its surrounding collective chamber. Fans 63 and 65, turning in the same direction, have air-intake openings 67 and 69 opposite each other, forming a space 61 between them, which is surrounded by an annular shroud 71 which has on its lowermost part an opening into which a collecting drawer 73 is inserted.

When in operation the fans suck the air through channel 51 downward through space 61 into the fan intakes 67 and 69. Since the fan rotors are turning in the same direction, the entire air column in space 61 receives a turning motion in direction of arrows 75, similar to ,a

tornado created by nature. That circular motion of the air with its highest circumferential air velocities on its outermost diameter about equal to the diameter of the inlet openings of the fans, by centrifugal force throws out the remaining dust and lint and so acts as a secondary filter or as the second stage of a two-stage air purifier. The dust and lint separated out of the air stream by that device is collected in drawer 73. The clean air discharged through the fan outlets 77 is then guided between internal walls of the machine forming the space 79 which carries in its uppermost portion two openings 81, covered with ornamental wire screening, through which the clean air is released back into the workroom.

The above description of the new separator having as its objective a cleaner finished product at a higher yield shows certain units grouped together a certain way. Since a grouping together of the same or similar units in a different order will result in the same end product, viz., cleaner tobacco at a higher yield, that description shall not be limited to the construction shown and described but to include all others giving the same end result.

While we have shown a separator employing our components grouped together in a particular arrangement, it will be appreciated that this construction can be rearranged and still incorporate the inventive features of this disclosure.

The invention herein above described may, therefore, be varied in construction within the scope of the claims, for the particular device selected to illustrate the invention, is but one of many possible embodiments of the same. The invention, therefore, is not to be restricted to the precise details of the structure shown and described.

What is claimed is:

l. A separating apparatus for torn tobacco leaves and stems comprising, an air passageway, means for discharging a continuous stream of torn tobacco leaves into said air passageway at a point where the velocity of the air stream in said air passageway will be such that the stems settle downwardly while the torn lamina is carried upwardly, a lamina separating chamber forming part of said passageway, the outside of said chamber having a curved and screened wall along which the lamina and heavier sand particles are hurled outwardly by centrifugal force as they travel around the same, thereby separating the lamina and sand from each other and from the air stream by allowing the sand to pass through the screened wall, means for causing a stream of air to flow through said air passageway and said separating chamber, a revolving gate positioned at the lower end of said lamina separating chamber for removing said centrifugally separated tobacco leaf lamina as it settles downwardly, and a sand collector for receiving the sand which passes through the screened wall.

2. A separating apparatus for torn tobacco leaves comprising, an air passageway, means for discharging a continuous stream of torn tobacco leaves into said air passageway at a point where the velocity of the air stream in said air passageway will be such that the stems settle downwardly while the torn lamina is carried upwardly, a lamina separating chamber forming part of said passageway, the outside of said chamber having a curved wall along which the lamina and heavier sand particles are hurled outwardly by centrifugal force as they travel around the same, thereby separating the lamina and sand from the air stream, a screen connected to the curved wall and declining downwardly at an angle in front of the lower end of said curved outside wall, ermitting heavy particles of sand separated by centrifugal force to pass therethrough and slide downwardly on that portion of the curved wall of said separating chamber below said screen, while preventing the torn tobacco leaf lamina from passing through the screen, means for causing air to flow through said air passageway and said separating chamber, a continuous conveyor positioned at the lower end of said collecting wall for removing sand continuously, and a revolving gate positioned at the lower end of said lamina separating chamber for removing said centrifugally separated tobacco leaf lamina as it settles downwardly.

3. A torn tobacco leaf separating apparatus comprising, a housing, an air passageway formed in said housing, the forward end of said air passageway having a first expansion chamber, a feeder for delivering a continuous stream of torn tobacco leaves to said first expansion chamber, a second separating chamber interconnected with said first expansion chamber for separating tobacco leaf lamina from the air stream, the air passageway connecting the second chamber with the first chamber having a curved exterior wall immediately adjacent to the second expansion chamber so as to cause the torn tobacco leaf lamina pneumatically carried by said air stream to be hurled outwardly by centrifugal force as it travels around said curved exterior wall into said second expansion chamber, a screen forming a continuation of said curved exterior wall and extending downwardly at an angle inside of said second separating chamber to cause separated tobacco leaf lamina to be directed downwardly while allowing sand to pass through said separating screen, means for causing air to flow through said air passageway and said chambers, a discharge air gate positioned at the lower end of said second separating chamber for removing tobacco leaf lamina that has settled downwardly in said chamber, and means positioned under said screen for receiving said separated sand and for conveying it therefrom.

4. Apparatus for separating torn tobacco leaves into separate categories, said separating apparatus comprising, a housing, an air passageway formed in said housing, a first separating area formed in said passageway for causing stems to be separated from torn tobacco leaves hurled into first separating area, a conveyor for delivering and hurling a continuous stream of torn tobacco leaves into said first separating area, a second separating area formed in said air passageway and interconnected with said first separating area by said air passageway, the outside wall of said air passageway connecting with said second separating area, having a curved configuration for causing tobacco leaf lamina carried by said air stream to be thrown outwardly under the action of centrifugal force to effect a separation of the torn lamina from the air stream as it goes around said curved wall into the second separating area, a screen connected at its upper end with said curved wall and forming a continuation thereof for allowing sand to pass therethrough while deflecting any tobacco leaf lamina falling thereon downwardly to the bottom of said second separating area, an air gate formed at the bottom of said separating area for discharg. ing separated lamina from said separating area, and means for causing air to flow through said air passageway and said separating areas.

5. Apparatus for separating torn tobacco leaves into components, comprising, an air passageway formed in said apparatus, a first separating station formed in said air passageway, means for delivering continuously torn tobacco leaves to said first separating station, a second separating station for separating lamina from the air stream, a curved wall formed in said air passageway and connecting with said second separating station to cause torn tobacco leaf lamina to be hurled outwardly as the air stream travels around said bend, an inner wall spaced opposite to said bend and having a tear-drop cross-sectional configuration at the downstream end thereof, a lower wall spaced from said tear-drop configuration and forming an orifice therewith through which air can escape which has had the lamina removed therefrom by centrifugal force, an air gate positioned at the bottom of said second separating station for removing tobacco leaf lamina separated from said air stream in said second separating station, and means for causing a stream of air to pass through said air passageway and said separating sta tions.

6. An apparatus having the features provided for in claim 5, wherein a diffuser screen is positioned in front of the air stream after it has passed through said orifice to diffuse the air stream, an air gate positioned between the lower end of said diffuser screen and the lower end of said inner wall to remove and discharge sand and torn tobacco leaves that settle downwardly, small diameter cyclone filters having their intake ducts mounted to receive said diffused air from said difiuser screen, a dust collecting chamber connected with the dust discharge end of said filters, a screw conveyor mounted at the lower end of said dust chamber for removing dust and sand separated by said cyclone separators.

7. An apparatus having the features provided for in claim 6 wherein spaced suction fans are provided for drawing air from and through said cyclone separators in a direction transverse to the direction in which said air enters the intake side of said suction fans so that a swirling vortex is formed immediately in front of the intake side of the suction fans and a dust collecting chamber positioned below the peripheral edge of said vortex to receive dust discharged by centrifugal action therefrom.

8. A pneumatic classifying apparatus for torn tobacco leaves comprising a housing having a first separating chamber for separating stems, a second separating chamher for separating stemless lamina, a third separating chamber for separating dust, ducts serially connecting said separating chambers, one of said ducts interconnecting said first separating chamber and said second separating chamber, the inner wall of said duct terminating in a teardrop-shaped guide part element, the outer duct wall immediately adjacent said second chamber being curved for causing stemless lamina to be hurled outwardly by centrifugal force as it travels around said curved surface in being discharged into said second separating chamber, means for causing air to flow through said chambers and an air gate positioned below said second separating chamber for removing stemless lamina sep arated from said air stream in said second separating chamber.

9. A pneumatic torn tobacco leaf classifier comprising a housing having a first classifying area for separating stems from torn tobacco leaves, means for delivering a continuous stream of torn tobacco leaves to said stem separating area, a second lamina separating area mounted in said housing, a duct interconnecting said stem separating area with said lamina separating area, the inner Wall of said duct terminating in a tear-drop shaped guide part element, the outer duct wall of said interconnecting duct, immediately adjacent to said second separating area, being curved to cause lamina conveyed by said air stream to be hurled outwardly against said curved wall as said air stream travels around said curve, thereby separating the lamina from the transporting air stream, a screen forming a continuation of said curved Wall allowing sand to trickle therethrough, the area immediately adjacent the tangential contact between said curved wall and said screen having a negative pressure due to said curved wall in conjunction with said tear-drop guide part of said second separating area, this area of negative pressure lifting the lamina from the curved wall and allowing said lamina to freely rotate in a turbulent air stream, means for causing air to fiow through said separating areas, a means positioned on the underside of-said second separating area for discharge of lamina settling out of the turbulent air stream, said discharge means permitting a certain amount of air to be admitted therethrough into the second separating area which supports the turbulence of the air stream therein, and a sand collecting device positioned under said sand screen.

10. A classifier for torn tobacco leaves comprising a housing, means for delivering a continuous stream of torn tobacco leaves to said housing, a first stern separatsesame ing area for receiving said torn tobacco leaves and pneumatically separating the stems from the torn leaves, a second separating area having a curved outer wall, a duct serially interconnecting said stem and lamina separating areas, said second separating area having an outlet orifice positioned at its upper end at a point spaced from said curved wall to exhaust air from said second separating area after lamina has been removed from said air, a screen tangentially connected at its upper end to said curved wall and spaced from said outer wall to allow sand particles separated from the air stream to trickle therethrough, the area immediately adjacent the tangential contact between the screen and the curved wall having a negative air pressure due' to said curved wall in conjunction with said orifice of the second separating area for causing separated tobacco leaf lamina to be sucked away from the curved wall into the second separating area, and means positioned on the underside of said second separating area for removing separated lamina therefrom.

11. A classifier for torn tobacco leaves comprising a housing, means for delivering a continuous stream of torn tobacco leaves to said housing, a stem separating area for receiving said torn tobacco leaves and pneumatically separating the stems from the torn leaves, a second separating area having a curved outer wall, a duct serially interconnecting said stem and second separating areas, said second separating area having an inner wall of tear drop shaped configuration at the downstream end thereof and a lower wall spaced from said inner wall to form an outlet orifice positioned at its upper end at a point spaced from said curved wall to exhaust air from said second separating area after lamina has been removed from air, a screen tangentially connected at its upper end to said curved wall and spaced from said outer wall to allow sand particles separated from the air stream to trickle therethrough, the area immediately adjacent the tangential contact between the screen and the curved wall having a negative air pressure due to said curved wall in conjunction with said orifice of the second separating area for causing separated tobacco leaf lamina to be sucked away from the curved wall into the second separating area, means positioned on the underside of said second separating area for removing separated lamina therefrom, an inner wall formed in said second separating area spaced from said screen, a diffuser screen positioned downstream of said outer orifice for diffusing the air stream passing through said opening, an air gate positioned at the lower end of said inner wall for discharging separated lamina falling behind said wall back into the second separating area, and means for causing air to fiow through said diffuser screen and separating areas.

12. A tobacco classifying apparatus comprising a housing, a source of supply of torn tobacco leaves, an air passageway for pneumatically conveying torn tobacco leaf components through said apparatus, a stem separating section formed in said passageway for receiving said torn tobacco leaves and pneumatically separating the stems from the lamina in this section, a lamina separating section formed in said air passageway, an opening formed at the upper end of said lamina separating section for removing air at the upper end of said section in a direction which is opposite to the centrifugal forces exerted on the lamina components as they are delivered around a curved path of travel into said lamina separating section, a diffuser screen positioned in the path of flow of said air stream after it has passed through said opening, a revolving gate positioned at the lower end of said lamina separating section to continuously remove lamina therefrom, a second discharge gate positioned below the front side of said diffuser to continuously discharge lamina falling downwardly in front of said diffuser into the first discharge gate, and a bank of small diameter cyclone separators positioned behind said diffuser to remove duct from said air stream.

13. A tobacco leaf classifier comprising a housing, an air passageway formed in said housing, a stem separating station formed in said passageway, means for delivering torn tobacco leaves to be classified to said air passageway, a lamina separating station formed in said passageway at a point posterior to said stem separating area, and a squirrel cage suction fan for drawing air through said air passageway, said squirrel cage suction fan being positioned at right angles to the stream of air traveling toward said suction fan so as to cause a vortex in front of the fan, and a dust collecting box positioned under said vortex in front of said fan to receive dust separated out of said air stream by said vortex before the air enters said suction fan.

14. A tobacco leaf classifier comprising a housing, an air passageway formed through said housing, a stem separating station formed in said passageway, means for delivering torn tobacco leaves continuously to the air passageway at said stem separating station, a lamina separating station formed in said air passageway at a point posterior to said stem separating passageway, cyclone dust separators interposed in said air passageway to separate dust from the air stream after it leaves said lamina separating station, a pair of spaced turbine fans for drawing air through said air passageway, said turbines being mounted so that its blades rotate in a plane which is substantially parallel to the direction which air flows toward said turbines so as to cause a vortex to be formed in the area in between the fans in front of the entrance thereto, and a dust collecting box positioned under said vortex to receive dust from the periphery thereof before the air enters the turbine suction fans.

15. A tobacco classifying apparatus comprising first and second classifiers having an air passageway for conveying torn tobacco leaves and other material along a predetermined path from said first to said second classifier, a reverse bend formed in said passageway to cause lamina and other material carried by said air stream to be hurled outwardly by centrifugal force as said air stream passes around said reverse bend, means for collecting and continuously removing lamina separated from said air stream, a screen forming a continuation of the outer curved wall of said reverse bend to allow sand hurled outwardly by centrifugal force to trickle therethrough, means for collecting and removing sand passing through said screen, an air diffuser interposed in said air passageway across the path of said air after it has passed around said sharp bend, a wall of small diameter cyclone separators having their intake ducts evenly distributed behind said diffuser to remove dust from said air stream, and a source of suction for drawing air through said air passageway.

16. A tobacco classifier having the features provided for in claim 15 wherein a chute is positioned in front of and below said air diffuser to gather together any lamina falling downwardly and in front of said diffuser, and an air gate positioned at the lower end of said chute for continuously removing such falling lamina and discharging same back into the lamina separating chamber.

17. A tobacco classifier having the features provided for in claim 15 wherein a chute is positioned in back of said second classifier and in front of said wall of small diameter cyclone separators to receive any particles of material falling downwardly after passing through said diffuser.

18. A tobacco classifying apparatus having an air passageway, means for causing a stream of air carrying tobacco material to be classified to flow therethrough, a tear drop shaped guide forming one wall of said air passageway for sharply reversing the direction of travel of said air stream, a lamina collecting station positioned below said tear drop shaped guide for receiving lamina separated out of said air stream by centrifugal force as the air stream travels around said curved path of travel, an air gate for continuously removing the lamina separated and discharged into said collecting station, said means serving to draw off air at the upper end of said separating chamber and delivering said air to small diameter 1,945,771 cyclone separators to have dust removed therefrom. 2,643,768

References Cited in the file of this patent UNITED STATES PATENTS 5 294,201

1,659,695 Mayhew Feb. 21, 1928 10 Dahlstrom Feb. 6, 1934 Eissmann June 30, 1953 FOREIGN PATENTS Switzerland Ian. 16, 1954

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