WO2000069290A9

WO2000069290A9 - Tobacco cutting method and system

Info

Publication number: WO2000069290A9
Application number: PCT/US2000/013066
Authority: WO
Inventors: Edward A Day; George Robert Scott; Francis Cunningham King Jr; Robert Neil Smith; Stephen Bellamah
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 1999-05-14
Filing date: 2000-05-12
Publication date: 2001-08-16
Anticipated expiration: 2001-11-14
Also published as: WO2000069290A1; AU4845000A

Abstract

An apparatus and method for cutting lamina portions of tobacco leaves (320) without severing at least some of the stems of the tobacco leaves (320). The cutting can be carried out using one or more cutting flows of water, air or focused energy such as laser or ultrasound. The cuts in the lamina portions can be intersecting cuts which allow easier separation of the lamina from the stems by a separator (240) or during threshing (250) of the leaves. The leaves can be conveyed (120) to a cutting device (130) comprising one or more fixed or reciprocating cutting flows which provide the desired cuts in the lamina portions of the leaves. The leaves can be passed through a separator (240) which separates the stems from the lamina after which the remaining stem containing material can be passed through the threshing line (250).

Description

TOBACCO CUTTING METHOD AND SYSTEM

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to methods and systems for cutting lamina portions of tobacco leaves, particularly to methods and systems for cutting lamina portions of tobacco leaves using a plurality of cutting flows. The present invention has particular applicability in tobacco leaf threshing processes and in the preparation of various tobacco products, such as cigarettes.

2. Description of the Related Art

Tobacco threshing processes are used in tobacco leaf processing facilities (stemmeries) to separate the lamina of the tobacco leaf from the stem or midrib thereof. The free lamina is then generally processed and used to form various tobacco products including, for example, cigarettes, cigars, pipe tobacco and chewing tobacco.

The separation of the lamina from the stems is generally accomplished by subjecting the tobacco leaves to a series of threshing processes. Each threshing process generally includes flailing the tobacco leaves and subsequently separating the free lamina from the attached lamina using a separator.

It is desirable in a threshing process to maximize the production of free lamina while producing sufficiently large free lamina pieces. The amount of lamina that is separated from the stem can be measured by the "threshing efficiency." As used herein, the "threshing efficiency" is derived by dividing the weight of the total free lamina present after the threshing process by the sum of the weight of the free lamina and the attached lamina (not including the weight of the stems) present prior to the threshing process. The free lamina produced by the threshing process should meet minimum size requirements to facilitate the use of the free lamina in the production of tobacco products. Typically, acceptable free lamina sizes include lamina pieces of about 0.25 by 0.25 inch or larger.

Unfortunately, threshing efficiency and lamina size generally exhibit an inversely proportional relationship. Therefore, in optimizing a threshing process, the threshing efficiency is typically balanced with the size of the free lamina produced. For example, current threshing processes generally exhibit threshing efficiencies ranging from about 50% to 75%. While higher threshing efficiencies are achievable, such improvements typically lead to an unacceptable decrease in the size of the free lamina produced.

In addition, current threshing processes produce free lamina having irregular shapes and sizes. Such irregularities may cause problems with respect to the production of tobacco products including, for example: losses at pack-out stations at the primaries; production of irretrievable tobacco dust and other losses of tobacco; roughening of the tobacco strip and other forms of degradation; complications at quality control; unpredictability during cutting operations when the strip is converted into cut filler; and inconsistencies of the filling power of the cut filler.

In view of the foregoing, there is a need in the art for apparatus and methods capable of increasing the threshing efficiency of a tobacco threshing process while substantially maintaining an acceptable size of the free lamina produced thereby. In addition, a need exists in the art for increasing the consistency of the shape and size of the free lamina produced in such a threshing process. SUMMARY OF THE INVENTION

According to one embodiment of the invention, a method of cutting tobacco is provided in which lamina portions of tobacco leaves are cut along cutting lines such that at least some of the cutting lines traverse the stem portions of the leaves without severing the stem portions. The cutting can be carried out using one or more cutting flows of a fluid, a particulate material or a form of energy. For example, the cutting can be carried out using water jets or air jets. It is preferred that at least some of the cutting lines intersect each other and/or the unsevered stem portions have a minimum predetermined diameter. Such cutting lines can be formed using a reciprocating cutting flow and/or plurality of spaced apart cutting flows. For example, the lamina portions of the tobacco leaves can be cut with a first plurality of spaced apart cutting flows followed by cutting the lamina portions of the tobacco leaves with a second plurality of spaced apart cutting flows. The first and second cutting flows can be arranged to cut the lamina portions while the leaves travel in the same direction or the first cutting flows can cut the lamina portions while the leaves travel in a first direction and the second cutting flows can cut the lamina portions while the leaves travel in a second direction which is different than the first direction. The cutting flows can be provided by any suitable equipment such as a water jet apparatus, an air jet apparatus, or an apparatus which forms a high intensity beam of energy such as a laser beam and/or focused acoustic energy. The cut tobacco can be fed to a separator or directly to a thresher for removal of lamina from stem portions having lamina attached thereto.

According to another embodiment of the invention, an apparatus for cutting tobacco is provided which includes a conveyor which transports tobacco leaves and a cutting device which cuts lamina portions of the tobacco leaves along cutting lines such that at least some of the cutting lines traverse stem portions of the leaves without severing the stem portions. It is preferred that the cutting device form the cutting lines such that at least some of the cutting lines intersect each other and/or the unsevered stem portions have a minimum predetermined diameter. Such cutting lines can be formed using a reciprocating cutting flow and/or plurality of spaced apart cutting flows. For example, the lamina portions of the tobacco leaves can be cut with a first plurality of spaced apart cutting flows followed by cutting the lamina portions of the tobacco leaves with a second plurality of spaced apart cutting flows. The first and second cutting flows can be arranged to cut the lamina portions while the leaves travel in the same direction or the first cutting flows can cut the lamina portions while the leaves travel in a first direction and the second cutting flows can cut the lamina portions while the leaves travel in a second direction which is different than the first direction. The cutting flows can be provided by any suitable equipment such as a water jet apparatus, an air jet apparatus, or an apparatus which forms a high intensity beam of energy such as a laser beam and/or focused acoustic energy. The cut tobacco can be fed to a separator or directly to a thresher for removal of lamina from stem portions having lamina attached thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiments thereof in connection with the accompanying drawings, in which:

FIG. 1 is a flow diagram of a tobacco cutting system according to one aspect of the present invention;

FIG. 2 is a flow diagram of a tobacco cutting system including two cutting devices, according to one aspect of the present invention; FIG. 3 is a side view of a tobacco cutting system according to one aspect of the present invention;

FIG. 4 is a plan view of a tobacco cutting system according to one aspect of the present invention;

FIG. 5 is a side view of a tobacco cutting system according to an alternative embodiment of the present invention;

FIG. 6 is a plan view of a tobacco cutting system according to an alternative embodiment of the present invention;

FIG. 7 is a schematic diagram of an exemplary threshing line according to one aspect of the present invention;

FIG. 8 A is a schematic diagram of a tobacco cutting system including two fixed cutting devices arranged to cut tobacco leaves traveling in longitudinal and transverse directions according to one aspect of the present invention, FIG. 8B is a schematic diagram of a tobacco cutting system including a reciprocating cutting device and a fixed cutting device arranged to cut tobacco leaves traveling in longitudinal and transverse directions according to another aspect of the present invention, and FIG. 8C is a schematic diagram of a tobacco cutting system including a reciprocating cutting device and a fixed cutting device arranged to cut tobacco leaves traveling in a longitudinal direction according to a further aspect of the present invention;

FIG. 9 is a plan view of an exemplary cutting flow pattern disposed upon a tobacco leaf, according to one aspect of the present invention; FIG. 10 is a plan view of an exemplary cutting flow pattern disposed upon a tobacco leaf, according to one aspect of the present invention;

FIG. 11 is a plan view of an exemplary cutting flow pattern disposed upon a tobacco leaf, according to one aspect of the present invention;

FIG. 12 is a schematic of an exemplary threshing machine line according to one embodiment of the present invention;

FIG. 13 is a schematic of an exemplary threshing machine which can be incorporated in the threshing line shown in FIG. 12; and

FIG. 14 is a schematic of an exemplary air separator which can be incorporated in the threshing line shown in FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The present invention provides an improved method and apparatus of recovering lamina from tobacco leaves. In conventional threshing arrangements, tobacco leaves are processed by beating the leaves to break off bits of lamina, the threshed material is passed through a separator wherein the loose lamina is separated from stems, and the threshing/separation process is repeated several times to obtain as much lamina as possible. The throughput of threshing operations is on the order of thousands of pounds of tobacco leaves per hour. As such, even minor (e.g., 1 to 10%) increases in recovery of lamina can provide significant savings in the cost of processing tobacco. In a stemming operation, the stem (mid-rib) which makes up to 20 to 25% of the leaf weight of a tobacco leaf is removed in a threshing machine. The output of such machines is lamina, small lamina, fines, dust, stems and stem fibers. If desired, the tip (upper 1/3) of the leaf can be removed and processed with lamina removed in the threshing operation. Prior to threshing, the leaves can be conditioned to a desired temperature and moisture content (e.g., 15 to 30%) by use of a vacuum chamber, steam cylinder and/or direct cylinder conditioner. After passing through a picking area to remove foreign material, the leaves can be subjected to reordering to obtain desired heat and moisture contents in the leaves. During threshing, the leaves are beaten to break off pieces of lamina and an air separator can be used to separate the lamina from the remaining stems with lamina attached thereto.

In general, threshing efficiency for a particular type of tobacco (e.g., flue cured or burley) can be optimized by adjusting the speed of rotation of the threshing machine, the amount of loading of the machine, the design of the thresher basket and/or the moisture content of the leaves. In addition, by providing the leaves with intersecting cuts through the lamina prior to entry into the threshing machine, it is possible to further improve the threshing efficiency. The threshing operation can be carried out in stages (e.g., 4 to 9 but usually 5 to 6 stages) wherein each threshing machine is followed by an air separator. In cigarette manufacture, it is desirable to provide lamina with sizes of 1 x 1 inch and Vi x Vz inch with a minimum of particles below 1/4 x 1/4 inch.

The conditioning process is designed to open up the tobacco leaves and make them soft and pliable so that they can be threshed with minimum generation of scrap. Vacuum conditioning involves a first step of near complete vacuum to remove non- condensible gases and cause evaporation of some of the moisture in the tobacco. The next step is to subject the tobacco to an atmosphere of live, saturated steam which upon contact with the cold tobacco condenses and raises the temperature and moisture of the tobacco. This cycle can be repeated to achieve a desired combination of temperature and moisture. Another conditioning technique is use of direct condition cylinders wherein the tobacco is broken down into individual leaves, conditioned in an ordering cylinder, subjected to picking, and ordered again before threshing. The ordering cylinder can include pins which lift and drop the tobacco as the cylinder rotates and the humid environment inside the cylinder causes the leaves to absorb moisture and heat. As a result of such conditioning, during threshing the stems are pliable enough not to break and the lamina is pliable enough to make the separation easier.

Threshing machines can include various mechanisms to remove the lamina from the stems. For instance, a rotary thresher includes a rotor which rotates teeth in a housing partially enclosed by a basket. The threshing action is accomplished when the moving teeth strike the tobacco leaves and tear or rip pieces of lamina from the leaves. The basket includes openings which act as a screen to determine the size of particles that leave the thresher and cause larger particles to recirculate for further threshing. The teeth preferably have square corners to facilitate the ripping/tearing action and with suitable conditioning (e.g., 18 to 22% moisture and 100 to 120°F temperature) pieces of lamina can be removed from the stems without breaking the stems (e.g., the stems bend rather than break). The tooth spacing of the threshers in a threshing line can be progressively decreased and/or the openings in the baskets of such threshers can be varied to achieve desired effects in each thresher. For example, the baskets of upstream threshers can include rows of diamond or saw tooth shaped openings and downstream threshers can include rows of round or elliptical holes. Thresher speeds can vary along the thresher line (e.g., around 400 rpm for the first stage thresher to around 1000 rpm for the fifth stage thresher).

The separation operation can be accomplished with various types of separators such as vertical and horizontal separators. A vertical separator can be loaded via conveyor or pneumatically and it is desirable that the separator be loaded such that flow is consistent and spread evenly across the winnower. A projecting mechanism such as a rotary winnower can be used to project the leaves at a desired angle across the chamber in a smooth and continuous flow. The speed and diameter of the winnower can be selected such that heavier particles strike the far wall of the separating chamber and lighter lamina can be carried away by a vertical airstream. Flotation separation balances the upward force on the leaf caused by the vertical airstream against the downward force of gravity. As some free lamina can be balled up and/or some large lamina can have a piece of stem attached thereto, some objectionable stem content can be recovered with the free lamina and the total recovery of available free lamina may range from 85 to 90%. The lift in the chamber will depend on the amount of air flowing in the system and the density of the air. In a threshing line, one or more separators in series can be used to separate the output of an individual threshing machine.

The present invention provides methods and systems for improving the threshing operation by preceding the threshing operation with a cutting apparatus which provides intersecting cuts in the lamina of tobacco leaves and/or provides cuts in the lamina without cutting through the stems of the leaves. Advantageously, the cutting apparatus can be retrofitted into an existing threshing process line or incorporated in a custom designed threshing line.

Referring to FIG. 1, according to one aspect of the present invention, a system 100 for cutting tobacco is provided. The system 100 includes a tobacco leaf source 110 which provides the tobacco leaves to be processed. A conveyor 120 transports a layer of tobacco leaves from the tobacco leaf source 110. A cutting device 130 is proximately arranged to the conveyor 120. The cutting device 130 emits a plurality of cutting flows which provides intersecting and/or non-intersecting cuts in lamina portions of the layer. At least some of the cuts in the lamina portions traverse the stem portions of the leaves without severing the stems, e.g., without cutting stem portions having a predetermined diameter or greater. For instance, the usable stem portion of a tobacco leaf can range from 1/4 to 1/3 of the stem length and such usable stem portions can be severed and recovered along with the lamina portions for further processing of tobacco. On the other hand, the objectionable stem portion, e.g, the stem portion above a predetermined diameter such as 3/32 inch, is preferably not severed during the cutting operation. The system 100 may operate on a batch or continuous basis, preferably on a continuous basis.

Cutting the lamina portions of the tobacco leaves using the present system 100 typically increases the threshing efficiency of the threshing process while producing sufficiently large free lamina pieces. In addition, the consistency of the shape and size of the free lamina produced is typically increased. Compared to a conventional threshing line wherein leaves are passed sequentially through threshers and separators, according to the present invention the cut leaves can be passed through an optional separator prior to entering a threshing line. As a result, lamina can be removed prior to the occurrence of any threshing and the threshing line can be shortened by eliminating one or more thresher/separator combinations.

The tobacco leaf source 110 provides tobacco leaves which are suitable for use in forming tobacco products including, for example, cigarettes, cigars, pipe tobacco and chewing tobacco. The tobacco leaf source 110 may include any device suitable for providing a substantially consistent flow of tobacco leaves including, for example, a pin feeder.

The tobacco leaves are preferably subjected to a conditioning process prior to being introduced to the conveyor 120. The conditioning process prepares the tobacco leaves for threshing by opening up and/or moistening the leaves. Conditioning the leaves typically increases the size of the free lamina generated and reduces the amount of fines, scrap and dust produced during threshing. The conditioning process generally includes regulating the moisture and temperature of the tobacco leaves using equipment such as an ordering cylinder. For example, typical desired moisture levels for flue cured tobacco and burley tobacco are about 21%> and about 25%, respectively.

Referring to FIG. 3, the conveyor 120 is arranged to receive tobacco leaves

310 from the tobacco leaf source 110. The tobacco leaves 310 form a layer 320 of individual or overlapping tobacco leaves upon the conveyor 120. The tobacco leaf source 110 preferably provides tobacco leaves 310 at an upstream portion 122 of the conveyor 120. Also, the tobacco leaf source 110 preferably provides tobacco leaves 310 at a speed that is less than the speed at which the layer 320 of tobacco leaves is transported by the conveyor 120. This reduces or prevents the accumulation of tobacco leaves upon the conveyor 120.

The tobacco leaf source 110 may provide the tobacco leaves 310 as a randomly arranged mixture. In an alternative embodiment, the tobacco leaves 310 may be prearranged either by hand or machine. For example, the tobacco leaves 310 may be aligned in a particular direction to facilitate processing. Also, the leaves can be partially oriented such as in the case where at least some of the leaves become aligned in the direction of travel as they move towards the cutting station.

The layer 320 of tobacco leaves includes lamina portions and stems portions. Generally, the lamina portions include both free lamina and lamina that is attached to stems, i.e., attached lamina. Typically, the majority of the lamina that is provided by the tobacco leaf source 110 is attached lamina. In the case of overlapping or single layer leaves, the layer 320 of tobacco leaves preferably has a substantially even thickness of, for example, less than about 0.5 inch, more preferably the thickness of a single layer of tobacco leaves. Due to the natural contours of the tobacco leaves 310, the layer 320 is typically not flatly disposed against the conveyor 120. The amount of tobacco leaves 310 that may be processed using the present system 100 depends upon various factors including, for example, the capacity and mass flow rate of the conveyor 120 and the thickness of the layer 320. The amount of tobacco leaves 310 that can be processed can range from about 1,000 to 20,000 lbs/hr, e.g., preferably about 7500 to 15,000 lbs/hr.

The conveyor 120 may include any device capable of transporting the layer 320 of tobacco leaves. In a preferred embodiment, the conveyor 120 includes an inclined surface 300 whereupon the layer 320 of tobacco leaves is transported. The tobacco leaves 310 are preferably introduced to the inclined surface 300 at an upper portion 302 thereof, and gravitational forces slide the layer 320 of tobacco leaves down the inclined surface 300. When randomly arranged tobacco leaves 310 are provided, the tobacco leaves 310 may become aligned in a particular direction as they are transported down the inclined surface 300. To facilitate transport of the tobacco leaves, the inclined surface 300 is preferably formed from a material having a low coefficient of friction such as, for example, stainless steel. Also, a plurality of elongated protrusions 304 arranged parallel to the direction of the movement of tobacco may optionally be disposed upon the inclined surface 300 to facilitate transport and/or alignment of the leaves.

Referring to FIG. 5, in an alternative embodiment, the conveyor 120 includes at least one moving, endless conveyor belt 500 actuated by a power source 510, such as an electric motor. In this embodiment, the layer 320 of tobacco leaves is transported upon the surface of the at least one conveyor belt 500. The at least one conveyor belt 500 may be formed from an elastic material, such as rubber, or a rigid material, such as Fourdrinier wire. Alternatively, a second conveyor can be arranged above the conveyor 120 such that the tobacco leaves are transported between opposed surfaces of the two conveyors. In a further alternative embodiment, the conveyor 120 includes at least one moving, endless conveyor belt which is inclined. In this embodiment, gravitational force facilitates the transport of the layer 320, in addition to the moving conveyor belt.

Referring to FIGS. 3 and 4, the cutting device 130 is arranged downstream from the tobacco source 110 proximate to the conveyor 120, preferably above the conveyor 120. The cutting device 130 emits a plurality of flows which contact the layer 320. According to one aspect of the invention, the cutting device 130 includes a plurality of dischargers 132. The plurality of dischargers 132 emit a plurality of cutting flows which cut lamina portions of the layer 320 without severing stem portions of the layer 320 having a predetermined diameter or greater. Severing the stem portions is undesirable because attached lamina is generally more easily removed from longer stem portions than from shorter stem portions. Preferably, the predetermined diameter of the uncut stem portions is about 1/32 inch or greater, more preferably about 3/32 inch or greater. In this embodiment, stem portions having a diameter less than about 3/32 inch may be severed and included in the free lamina product. However, the preferred practice is to limit objectionable stem content in recovered lamina to about 5% or less.

The number of dischargers 132 and the position of each discharger 132 may be adjusted such that a desired distribution of lamina piece sizes may be ultimately obtained. In an exemplary arrangement, the cutting device 130 includes 30 to 60, e.g.,

48 dischargers 132. The plurality of dischargers 132 may be linearly arranged in a single row. Alternatively, the plurality of dischargers 132 may be arranged in a plurality of rows, preferably staggered rows. In a preferred embodiment, the plurality of dischargers 132 are effectively arranged to provide an approximate 1 inch space between cutting flows. However, 1 inch cutting lines in the leaves can also be provided by arranging a first row of dischargers at 2 inch spacings therebetween and a second row of dischargers at the same 2 inch spacings but offset 1 inch from the first row of dischargers. Such an arrangement would provide dischargers 132 which are arranged in a plurality of staggered rows. The plurality of dischargers 132 may be arranged such that the plurality of cutting flows contact the layer 320 at any angle, preferably the angle most effective to cut lamina portions of the layer 320. For instance, the cutting flows can be oriented peφendicular to the top surface of the layer

320 and/or the direction of cutting the leaves can be parallel to the direction of movement of the layer or at an angle thereto. However, it may be desirable to make the direction of cutting such that it is not perpendicular to the surface on which the tobacco leaves is supported.

Referring to FIG. 10, the cutting device 130 is preferably fixed, thereby imparting a cutting flow pattern (A) upon the layer 320 comprising multiple parallel lines. Referring to FIG. 11, in an alternative embodiment, the cutting device 130 may reciprocate in a direction traverse with the direction in which the layer 320 is transported. Such reciprocating action enables the formation of various cutting flow patterns upon the layer 320. For example, the cutting device 130 may reciprocate in a direction perpendicular to the direction of the flow of the layer 320 upon the conveyor 120, thereby producing a cutting flow pattern comprising multiple parallel sine waves (B). The amplitude and frequency of the waves of the sine wave cutting flow pattern may be changed by adjusting various parameters including, for example, the velocity of the conveyor 120, the time period of each reciprocation and/or the spatial displacement of each reciprocation. It will be appreciated that the desired cutting pattern can be provided by a plurality of dischargers or a single discharger which is reciprocated or moved to achieve the desired pattern of cuts. FIG. 11 shows an example of how a pair of cutting devices can be used to provide intersecting sinusoidal cuts in the lamina portions of the tobacco leaves. Although the cuts can be provided in the lamina portions using a reciprocating cutting device or using one or more fixed cutting stations, it will be appreciated that the desired cutting action can also be achieved by reciprocating the conveyor past a fixed cutting station. A preferred cutting device 130 emits a plurality of cutting flows of a fluid, a particulate material or a form of energy. This includes continuous, intermittent or pulsed flows of any liquids, gases, solids or forms of energy which are capable of cutting tobacco lamina. For example, the flows may be formed from water, air, sand, light or sound. Preferably, the flows are of a pressurized fluid, more preferably pressurized water. Details of a suitable water jet arrangement which can be used to form the cutting flows will be apparent to those skilled in the art. See, for example, U.S. Patent No. 4,640,300, the disclosure of which is hereby incoφorated by reference. The pressure of the fluid and/or size of the fluid jet stream are adjusted such that the flow cuts lamina portions of the layer without severing stem portions of the layer having a predetermined diameter or greater and/or stem portions having a substantial length. For example, the pressurized water flows are preferably at a pressure from about 10,000 to 70,000 psi, and more preferably about 30,000 to 40,000 psi. In this embodiment, the cutting device 130 comprises a plurality of nozzles which emit the flow of pressurized water. Such nozzles preferably have a diameter in the range of approximately 0.003 to 0.008 inch, more preferably about 0.004 to 0.005 inch. The pressurized water is typically provided by using a pump, such as that available from Flow Automation.

Alternatively, the plurality of cutting flows may be formed of material other than water. For example, other liquids may be used, such as propylene glycol. In an alternative embodiment, pressurized flows of air may be provided or other gases such as nitrogen or CO₂ can be used, the pressures of which can be adjusted to achieve the desired cutting action. In another alternative embodiment, lasers of focused acoustical energy may be provided to cut the lamina portions of the tobacco leaves. The use of lasers may require an inert atmosphere, such as a nitrogen atmosphere, to reduce or prevent the occurrence of fires. In an alternative embodiment, the cutting device 130 emits the plurality of cutting flows through a moving orifice applicator such as that shown and described in U.S. Patent No. 5,997,691, the contents of which patent are hereby incoφorated by reference.

In the embodiment shown in FIG. 3, the system 100 preferably includes a holding device 330 for applying pressure to the layer 320 to reduce the shifting of the tobacco leaves when the plurality of cutting flows contacts the layer 320. The holding device 330 may also flatten the layer 320 prior to cutting. The system 100 preferably includes two or more holding devices 330 arranged in series. For instance, the hold down device can comprise a flat roller for flattening the leaves, a first roller set having a row of spaced apart wheels which convey the leaves past the cutting station which cuts the leaves at positions corresponding to the spaces between the wheels, and a second roller set having a row of spaced apart wheels which are interleaved with the wheels of the first roller set and serve to prevent the cut leaves from curling up.

In a preferred embodiment, the holding device 330 includes a plurality of rotating wheels or discs 332 proximately arranged to the conveyor 120, preferably above the conveyor 120, as illustrated in FIGS. 3 and 4. The distance between the lowermost portion of the plurality of rotating discs 332 and the uppermost portion of the conveyor 120 is preferably less than the thickness of the layer 320. The plurality of rotating discs 332 preferably extends across the entire width of the conveyor 120, thereby accommodating the entire layer 320 thereunder. The plurality of rotating discs 332 preferably contacts the layer 320 at a location in the vicinity of but downstream from the cutting device 130. In a preferred embodiment, the plurality of rotating discs 332 is powered by a power source 340, such as an electric motor, to regulate the speed of movement of the layer 320. The rotating discs 332 are preferably formed of a plastic, metal or polymer material which is compatible with tobacco processing. Further, the outer peripheries of the discs are preferable covered with a conveyor belt material which aids in gripping the leaves and feeding the leaves in a downstream direction. Such belting material can include a pattern of projections of resilient material which is effective in reducing or preventing clogging of tobacco leaves between the holding device 330 and the conveyor 120, e.g., the outer surface of the holding device 330 which contacts the layer 320 may be formed of a material such as rubber which is sufficiently flexible to permit passage of irregularly large agglomerations of tobacco leaves in the layer 320. As an example, an inflatable natural rubber element which provides the desired yielding to varying thicknesses of the tobacco can be used on the outer periphery of each disc.

The plurality of rotating discs 332 is preferably spaced from about 1.5 to 5 inches apart, more preferably about 2 inches apart. According to one aspect of the invention, the plurality of rotating discs 332 is alternatingly arranged with the plurality of dischargers 132. The dischargers 132 are preferably aimed to direct the cutting flows at points upon the layer 320 proximate to the pinch point 334 between the holding device 330 and the surface of the conveyor 120 whereby the cutting lines are formed in the leaves at positions between the discs.

According to a preferred embodiment, a plurality of orifices 350 are disposed upon the surface of the conveyor 120 to allow cutting fluid which cuts through the layer 320 to pass through the conveyor 120. This typically reduces wear upon the conveyor 120 and decreases the amount of cutting flow material, such as water, which is absorbed by the layer 320. Referring to FIG. 6, according to an alternative embodiment in which the conveyor 120 includes a plurality of parallel spaced- apart conveyor belts 500, the cutting flows may pass through the spaces 600 between the conveyor belts 500. Referring to FIG. 3, a plurality of flow-receiving devices 260 may be arranged to at least partially contain and collect each cutting flow that passes through the layer 320 and conveyor 120. Referring to FIGS. 2 and 8, according to a further aspect of the invention, a system 200 includes a tobacco leaf source 110, a first conveyor 120, a first cutting device 130 proximately arranged to the first conveyor 120, a second conveyor 220, and a second cutting device 230 proximately arranged to the second conveyor 220. A controller 140 can be used to operate the cutting devices and operate a high pressure fluid supply 150 to supply pressurized fluid such as water to the cutting devices. The second conveyor 220 is preferably arranged downstream from the first conveyor 120 and at an angle with respect to the first conveyor 120, preferably from about 45 ° to 135 °, more preferably at about 90°. After exiting the second conveyor, the cut leaves are transported to an air separator 240 which separates cut strip 242 from material 244 having stems attached with flags 246 attached thereto. The material 244 is then transported to a threshing line 250 for further processing.

In this embodiment, the layer 320 which is passed through the first cutting device 130 is directed from the first conveyor 120 to the second conveyor 220 such that the shifting of tobacco leaves in the layer 320 is minimized or eliminated. For example, a sweep feed device 210 may be used to direct the layer 320 from the first conveyor 120 to the second conveyor 220. The second conveyor 220 and the second cutting device 230 operate in an identical manner as the first conveyor 120 and first cutting device 130, as described above. The system 200 may also include various aspects of the system 100 described above.

As explained above, FIG. 8A shows a tobacco cutting system including two fixed cutting devices arranged to cut tobacco leaves traveling in longitudinal and transverse directions according to one aspect of the present invention. Another suitable arrangement is shown in FIG. 8B wherein a tobacco cutting system includes a reciprocating cutting device 131 and a fixed cutting device 231 arranged to cut tobacco leaves traveling in longitudinal and transverse directions. FIG. 8C shows a further arrangement of a tobacco cutting system including a reciprocating cutting device 133 and a fixed cutting device 233 arranged to cut tobacco leaves traveling in a longitudinal direction.

Referring to FIG. 9, the second cutting device 230 cuts lamina portions of the layer 320 in a direction which is transverse to the direction in which the first cutting device 130 cuts the lamina portions of the layer 320. In this manner, various cutting flow patterns may be achieved. The system 200 may thereby produce free lamina of various shapes and sizes, e.g., pieces of lamina ranging in size from 1/16 inch to > inches.

Referring to FIG. 7, a threshing line 700 according to an exemplary aspect of the present invention includes the system 100 of the present invention. The system

200 which includes two cutting devices may alternatively be used. The cut layer of tobacco leaves is produced by the system 100 and is subsequently passed through a separating device 710, such as the air separator shown and described in U.S. Patent No. 4,465,194 to Coleman, the contents of which patent are hereby incoφorated by reference. The separating device 710 separates the free lamina from the attached lamina. The separated free lamina is recovered as product and the separated attached lamina is distributed among a plurality of threshers 720 arranged in parallel, preferably two threshers. The threshed tobacco leaves are then passed through a plurality of separators 730 arranged in series, preferably three separators, to separate the free lamina from the attached lamina. The free lamina may then be recovered as product and the attached lamina may be further threshed, preferably by recycling the attached lamina to the plurality of threshers 720.

FIG. 12 shows an example of a threshing line 800 which can receive the output of the cutting apparatus 802 in accordance with the invention. As shown, the threshing line 800 includes a pin feeder 802, a vibrating conveyor 804, a cutting apparatus 806, an air separator 808, a thresher 810, and an air separator 812. If desired, additional threshers and separators can be added to the line to effect further threshing and separation of the lamina from the stems. For example, the threshing operation can be carried out in 6 to 8 stages and the recovered lamina can have sizes on the order of 1 x 1 inch to ^lA x ^lA inch with a minimum of particles below 1/4 x 1/4 inch.

FIG. 13 shows an example of a threshing machine 820 which includes an inlet 822, door teeth 824, rotor teeth 826, a rotor 828, a basket 830 and a tooth clearance 832 of, for example, about up to 1/4 inch. The threshing action is accomplished when the moving teeth strike the tobacco leaves and tear or rip pieces of lamina from the leaves and openings in the basket allow certain sizes of particles to leave the thresher while maintaining larger particles in the thresher for further threshing.

FIG. 14 shows a vertical separator 840 wherein a projecting mechanism 842 such as a rotary winnower projects the leaves at a desired angle across the chamber 844 in a smooth and continuous flow. The speed and diameter of the winnower can be selected such that heavier particles strike the far wall of the separating chamber and lighter lamina can be carried away by a vertical airstream 846. In a threshing line, one or more of such separators in series can be used to separate the output of an individual threshing machine.

While the invention has been described in detail with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made, and equivalents employed without departing from the scope of the claims.

Claims

WH T IS CLAIMED IS:

1. A method of cutting tobacco leaves comprising cutting lamina portions of tobacco leaves along cutting lines, at least some of the cutting lines traversing the stem portions of the leaves without severing the stem portions.

2. The method according to claim 1, wherein the cutting is carried out using one or more flows of a fluid, a particulate material or a form of energy.

3. The method according to claim 1, wherein the cutting is carried out using a plurality of water jets or a plurality of air jets.

4. The method according to claim 3, wherein the water jets are formed by passing pressurized water through spaced apart nozzles, the pressurized water being at a pressure of 10,000 to 70,000 psi..

5. The method according to claim 3, wherein the water jets are formed by passing pressurized water through spaced apart nozzles, the pressurized water being at a pressure of 30,000 to 40,000 psi..

6. The method according to claim 1, wherein at least some of the cutting lines intersect each other.

7. The method according to claim 1, wherein the cutting is carried out using a plurality of cutting flows spaced about 1.5 to 5 inches apart.

8. The method according to claim 1, further comprising separating lamina from stem material having lamina attached thereto by passing the cut tobacco leaves through a separator followed by passing the stem material having lamina attached thereto through a threshing line.

9. The method according to claim 1, further comprising separating lamina from stem material having lamina attached thereto by passing the cut tobacco leaves through a threshing line.

10. The method according to claim 1, wherein the cutting is carried out using a single reciprocating cutting flow, a plurality of cutting flows arranged in a single row or a plurality of cutting flows arranged in aligned or staggered rows.

11. The method according to claim 1 , further comprising feeding the leaves along a conveyor which includes an arrangement which orients the leaves in a direction such that at least some of the stems of the leaves are aligned in the direction of travel of the leaves .

12. The method according to claim 1, further comprising feeding the leaves along a conveyor such that the leaves are in random orientation with respect to a direction of travel of the leaves along the conveyor.

13. The method according to claim 1, further comprising a step of continuously transporting the tobacco leaves in a longitudinal direction down an inclined surface towards a cutting station at which the cutting lines are formed.

14. The method according to claim 1, wherein the leaves are transported in a longitudinal direction and the cutting is carried out using one or more cutting flows which reciprocate in a direction traverse to the longitudinal direction.

15. The method according to claim 1, further comprising a step of holding down the leaves while they are being cut, the hold down device including a first roller set having spaced apart discs and a second roller set having spaced apart discs, the discs of the first and second roller sets being interleaved, and the cutting lines being formed at positions corresponding to spaces between the discs of the first roller set.

16. The method according to claim 1, wherein the cutting is carried out such that the stems which are not severed have a diameter of about 3/32 inch or greater.

17. The method according to claim 1, wherein the cutting is carried out such that the stems which are not severed have a diameter of about 1/32 inch or greater.

18. The method according to claim 3, further comprising a step of passing the water jets through openings in a conveyor on which the leaves are transported.

19. The method according to claim 1, wherein the cutting is carried out using one or more first cutting flows and one or more second cutting flows, the one or more first cutting flows cutting the lamina portions of the leaves while the leaves travel in a longitudinal direction and the one or more second cutting flows cutting the lamina portions of the leaves while the leaves travel in a transverse direction.

20. The method according to claim 1, wherein the cutting is carried out using one or more first cutting flows and one or more second cutting flows, the one or more first cutting flows cutting the lamina portions of the leaves while the leaves travel in a longitudinal direction and the one or more second cutting flows cutting the lamina portions of the leaves while the leaves travel in the longitudinal direction.

21. The method according to claim 1, wherein the cutting is carried out using a single reciprocating cutting flow of pressurized water jets.

22. The method according to clim 1, wherein the cutting is carried out using a single reciprocating bank of spaced apart cutting flows of pressurized water jets.

23. The method according to claim 1, wherein the cutting is carried out using a first fixed or reciprocating bank of spaced apart cutting flows of pressurized water and a second fixed or reciprocating bank of pressurized water jets.

24. An apparatus for cutting tobacco leaves comprising: (a) a conveyor which transports tobacco leaves; and

(b) a cutting device which cuts lamina portions of the tobacco leaves along cutting lines such that at least some of the cutting lines traverse stem portions of the leaves without severing the stem portions.

25. The apparatus according to claim 24, wherein the cutting device cuts the lamina portions with one or more flows of a fluid, a particulate material or a form of energy.

26. The apparatus according to claim 24, wherein the cutting device comprises a plurality of water jets or a plurality of air jets.

27. The apparatus according to claim 26, wherein the cutting device includes a source of pressurized water and spaced apart nozzles, the pressurized water being at a pressure of 10,000 to 70,000 psi.

28. The apparatus according to claim 26, wherein the cutting device includes a source of pressurized water and spaced apart nozzles, the pressurized water being at a pressure of 30,000 to 40,000 psi.

29. The apparatus according to claim 24, wherein the cutting device forms the cutting lines such that at least some of the cutting lines intersect each other.

30. The apparatus according to claim 24, wherein the cutting device includes an arrangement wherein a plurality of cutting flows are spaced about 1.5 to 5 inches apart.

31. The apparatus according to claim 24, further comprising a separator arranged to receive the cut tobacco leaves and separate lamina from stem material having lamina attached thereto and a threshing line arranged to receive the stem material having the lamina attached thereto from the separator.

32. The apparatus according to claim 24, further comprising a thresher arranged to receive the cut tobacco leaves and separate lamina from stem material having lamina attached thereto.

33. The apparatus according to claim 24, wherein the cutting device includes a single reciprocating cutting device, a plurality of cutting devices arranged in a single row, or a plurality of cutting devices arranged in aligned or staggered rows.

34. The apparatus according to claim 24, wherein the conveyor includes an arrangement which orients the leaves in a direction such that at least some of the stems of the leaves are aligned in the direction of travel of the leaves

35. The apparatus according to claim 24, wherein the conveyor feeds the tobacco leaves in random orientation with respect to the direction of travel of the leaves

36. The apparatus according to claim 24, wherein the conveyor is an inclined surface which transports the tobacco leaves in a longitudinal direction towards one or more cutting flows.

37. The apparatus according to claim 24, wherein the conveyor transports the tobacco leaves in a longitudinal direction and the cutting device includes an arrangement which reciprocates one or more cutting flows in a direction traverse to the longitudinal direction.

38. The apparatus according to claim 24, further comprising a hold down device which holds down the leaves while they are being cut, the hold down device including a first roller set having spaced apart discs and a second roller set having spaced apart discs, the discs of the first and second roller sets being interleaved, and the cutting lines being formed at positions corresponding to spaces between the discs of the first roller set.

39. The apparatus according to claim 38, wherein the hold down device further includes a roller upstream of the first and second roller sets, the roller causing the leaves to lie flat on the conveyor when they are cut.

40. The apparatus according to claim 26, wherein the conveyor includes openings through which the water jets pass after cutting the lamina portions of the leaves.

41. The apparatus according to claim 24, wherein the cutting device includes one or more first cutting flows and one or more second cutting flows, the one or more first cutting flows cutting the lamina portions of the leaves while the leaves travel in a longitudinal direction and the one or more second cutting flows cutting the lamina portions of the leaves while the leaves travel in a transverse direction.

42. The apparatus according to claim 24, wherein the cutting device includes one or more first cutting flows and one or more second cutting flows, the one or more first cutting flows cutting the lamina portions of the leaves while the leaves travel in a longitudinal direction and the one or more second cutting flows cutting the lamina portions of the leaves while the leaves travel in the longitudinal direction.

43. The apparatus according to claim 24, wherein the cutting device includes a single reciprocating cutting flow of pressurized water jets.

44. The apparatus according to claim 24, wherein the cutting device includes a single reciprocating bank of spaced apart cutting flows of pressurized water jets.

45. The apparatus according to claim 24, wherein the cutting device includes a first fixed or reciprocating bank of spaced apart pressurized water jets and a second fixed or reciprocating bank of apart pressurized water jets.

46. The apparatus according to claim 24, wherein the cutting device includes a first reciprocating bank of spaced apart pressurized water jets and a second reciprocating bank of apart pressurized water jets.

47. A method of stripping tobacco comprising the steps of: establishing a bed of tobacco leaves; cutting with fluid jets said bed in a first direction relative to said bed; cutting with fluid jets in a second direction relative to said bed, said second direction transverse to said first direction; at least one of said cutting steps further including the step of limiting cutting action of said fluid jets so that lamina portions of said tobacco leaves are cut and stem portions of said tobacco leaves remain substantially intact.

48. The process claimed in claim 47, wherein the tobacco is laid straight.

49. The process claimed in claim 47, wherein the tobacco is laid randomly.

50. A method of producing a supply of cut strip in proportion with a desired size distribution, comprising the step of mutually adjusting spacing between first and second transverse cuts in a bed of tobacco leaves while maintaining stem portions of said leaves in a substantially uncut condition.

51. A tobacco strip product comprising a plurality of double transverse cut tobacco lamina pieces, said lamina pieces transversely cut in accordance with a predetermined cut pattern of first and second mutually transverse directions.

52. An apparatus arranged to produce tobacco cut strip product comprising a plurality of double transverse cut tobacco lamina pieces, said lamina pieces transversely cut in accordance with a predetermined cut pattern of first and second mutually transverse directions.