Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
  • A24B5/00—Stripping tobacco; Treatment of stems or ribs
  • A24B5/16—Other treatment of stems or ribs, e.g. bending, chopping, incising

Definitions

• Cigarette making machines incorporate a high degree of automation capability. They are designed to accept and handle tobacco filler having particularly those characteristics described above which are peculiar to cut leaf blend. Any significant depar ⁇ ture from these characteristics may make a cigarette filler blend- unsuitable for proper feeding into automatic cigarette making equipment. Blends of cigarette filler which contain a mixture of shreds cut from leafy material and from stems wherein the cut stem content is proportionately above a certain level may not be a suitable feed material for such machines. When the percentage of cut stem shreds is too high, problems may be experienced in the operation of the equipment's tobacco filler feed mechanism. There may also be produced a certain excessive percentage of cigarettes which are rejected because of improper appearance or feel.
• stem shreds exhibit re ⁇ siliency; while stems, when cut across the grain under like condi- tions, may produce stick-like shreds or hard chunks of relatively high density. These hard stick-like shreds and chunks are less suitable as cigarette filler constituents.
• rela ⁇ tively short length and lack of springiness of cut stems reduces their contribution to blend filling power and increases their tendency to separate from the blend on handling.
• stem shred fragments which more nearly duplicate the texture of leaf shreds.
• Some prior art stem shredding methods have been used in an attempt to convert stems into such leaf-like fragments which would be compatible with leaf shreds in a filler mixture blend.
• Some progress has been made toward this objective by rolling the stems under pressure between pressure rolls.
• This process known as "rolling and cutting,” is a current industry standard.
• threshed bright and/or burley stems are moistened to 25 to 35% moisture content and then passed between press rolls to flatten the stems to a form more l ke leaf lamina. These flattened stems are then cut into shreds on a tobacco cutter and reordered to a moisture content suitable for blending with other tobacco filler components.
• stem shreds be made more like leaf shreds in appearance and texture
• stem shredding process it is desired to shred tobacco stems in such a way as to cause the stems to separate into fragments of curliform fibrous strands.
• An object of the present invention is to shred tobacco stems by splitting or parting the stems along the grain to produce light, pliable, low bulk density fibrillar shreds. Such shreds exhibit sufficient resiliency so that when massed they approximate or exceed the filling capacity of cut leaf shreds. Rolled and cut stem shreds tend to separate out on handling, while fibril!iform stem fragments of the present invention when mixed with leaf shreds counter this tendency toward separation.
• the present process utilizes blunt rotatable blade-like elements as hammers used to strike stem shards.
• Such blades are arranged to revolve at high speed within a moving stream of fluid- supported, dispersed, water-softened tobacco stem shards.
• the blunt blades travel at very high velocity within the stream of softened shards and strike the individual shards with force suf ⁇ ficient to cause spalling of the shards into fibers parting them along the grain of the stem to produce long fibrous shred fragments.
• the shards to be shredded are first wetted to a given desired moisture content. Wetting makes the shards pliable and avoids the production of an excessive number of short fibers.
• the shredding through spalling action is thought to result from impingement of the fast-moving blunt blades on the floating stems and stem shards by converting kinetic energy into internal stem energy on impact thereby causing shattering of the shards along the lines of the internal grain structure.
• This forms elongated fibrous shreds which are thence driven protreptically forward of the blades by the transfer of kinetic energy. They are thus repositioned to be struck again and again by succeeding blades.
• stem shreds made according to the prior art in a rolling process and cut by opposed shearing elements tend to exhibit undesirable features. Such features are short shred length, a high degree of hardness, and high bulk density which in each case results in lower filling power and poorer blendability with shredded leaf in cigarettes.
• the shreds produced by the present process possess improved ciga- rette filling power -per unit of weight over shreds produced by these former methods and exhibit greater resilience and subjec ⁇ tively produce a cigarette which has a smoother feel.
• an important aspect of the process of the present inven ⁇ tion is that the stems and stem shards are resiliently supported in a fluid medium against impact action of the blades.
• An "anvil- type" chopping block support for the shards or a shearing or cut ⁇ ting action by a traveling cutter blade against a rigid support is avoided in the present process which effects shredding and fiberi- zing by spalling action through the transfer of kinetic energy at the point of collision between a blade and a floating stem frag ⁇ ment. This results in explosive spallation and produces an
• Figure 1 is a Waring Blendor illustrated to show modifi ⁇ cation for adaptation to the present process.
• Figure 2 is a view in elevation showing a blade arrange ⁇ ment of a typical ha mermill and screening apparatus; i.e., a Fitzmill and a Sweco vibrating screen.
• Figure 3 is a diagrammatic showing of the related steps of the process.
• Figure 4 is a photograph of feed stock ' of stem shards.
• Figure 5 is a photograph showing the finished product of the present process. Best Mode for Carrying Out the Invention
• stem midribs separated from.a tobacco leaf in any satisfactory way are first treated with water in such a. anner as to thoroughly moisten the stems uniformly throughout.
• This moistening step may be effected by spraying, steaming, or immersing the stems in a water bath for a period of time as needed to achieve the desired level of moisture content. Moistening of the stems by subjecting the stems to the action of steam within a pressure vessel or at ambient pressures will result in accelerating the penetration of moisture into the stems.
• the moisture content it is desired to bring the moisture content to a level of from 40 to 75% with a preferred level being at least about 60% by weight, wet basis.
• a significantly lower moisture content will cause the production of an undesirable percentage of short shreds due to brittleness of the tobacco in the drier state.
• the stems after moistening, are introduced at a given rate of feed into a partially confined area in which striker blades are arranged to rotate at high speeds in accordance with the modes of the invention as hereinafter described.
• the moistened stems are shredded in the practice of one mode of the present invention in a
• the feed material 16 consists of tobacco ste shards which have been prepared by any suitable means (not shown) to a desired length known as "short stems" and preferably 1 to 3 inches in length prior to entry into the upper cone-like feed section 17 of the funnel 15.
• the shards 16 are fed by hand or mechanically into the funnel 15 at a suitable rate thence through the upper end 18 of the feed tube 19.
• the blade element 20 is rotated at approximately 21,000 revolutions per minute by means of a standard Waring Blendor motor 10. Shards are thus thrust centrifugally outward and accelerated forwardly, recirculated, and struck again repeatedly. A fresh supply of shards is fed through the funnel 15 until an equilibrium rate of feed of material entering at that point is matched to the effluent rate .of finished product exited through the slot 14.
• the gate element 21 is adjusted to a height of closure in slot 14 to control the depth of material in proximity to the blade 20. This determines the fineness of the shreds which are forced to the top of the torus 22 formed around the vortex 23 over ⁇ the blade 20.
• the recirculation time of the shards and shreds within the vortex 23 determines the fineness and final curliform characteristics in the completed shreds.
• the wide mouth funnel 15 as fitted to the jar top of the bowl 12 facil tates continuous addition of feed stems and performs the additional function of preventing stem shards and product from being ejected from the top of the jar by the force of blade impact.
• threshed stems softened by moistening to 40 to 75% moisture content, preferably above 60%, and holding or "bulking" 1 to 24 hours, preferably 1 to 2 hours, are added through the funnel 15 at a rate determined by the rate of shredded stem efflux through the slot 14 for a given preset height of the gate element 21.
• the shards and shreds in the rotating vortex 23 are supported above the shredding zone by air and centrifugal forces.
• Larger stem shards remain in the shredding zone until they are shattered into lighter fragments and become air supportable at the upper part of the torus for removal.
• the height of the bottom edge of the side- wall slot 14 is adjusted vertically by repositioning of the gate element 21. to a height to permit an optimum size, shape, and weight range of shredded stems to exit the bowl according to their rela ⁇ tive position in the circulating torus of finished product.
• the product removed through the slot 14 may be further separated (i.e., with a standard or preferably a slotted classi ⁇ fying screen, by centrifugal force or by air classification) and dried to a moisture content suitable for incorporation in a ciga ⁇ rette blend. Oversized material which remains after screening on a slotted classifying screen, not shown, may be recycled alone, directly to the blendor, or mixed with fresh stem feed. Thus, no oversized material ultimately remains by this mode of the process.
• the final product is composed totally of suitable filler and a small amount of fines which are separated for use elsewhere.
• An alternate form of the present process may be imple ⁇ mented with a Model M Fitzmill as shown in Figure 2 which is fitted with blunt-faced impact blades 34 and a 4-mesh exit screen 35.
• the particular unit is manufactured by The Fitzpatrick Company of Elmhurst, Illinois.
• Threshed stems softened by moistening to 40 to 75% moisture content, preferably above 60%, and then holding or "bulking" for 1 to 24 hours, preferably 1 to 2 hours, are submitted to the shredding zone of the Fitzmill at a rate which permits free circulation of the stems and ready access to spalling thereof by the rapid rotation of blades 34.
• the shredding mass of stems is forced by centrifugal action against the exit screen 35. As size and shape permit, the shredded stem fragments go through the screen 35.
• the crude shredded stem shards after passing through screen 35 are further separated from the finer shreds on a two-deck classifying screen assembly containing a suitably sized slotted upper screen 36 which may have slots ranging in size from 1 " x V' to 1" x 1/16" and a regular 30-mesh lower screen 37.
• Those stem shards remaining on the upper slotted screen 26 are called “heavies” and are recycled to the hammermill, either alone or in admixture with fresh stem feed.
• the fraction retained on the 30-mesh screen 37 is the product desired and is thereafter dried to a moisture suitable for cigarette blends.
• the smaller stem particles which pass through the 30-mesh screen 37 are not recycled to the mill. These are called fines and are carried away for use elsewhere.
• Example 1 Batch Waring Blendor Shredding
• a standard one-quart glass Waring Blendor bowl is equipped with a lid and a standard blade set of four blades and is powered by a commercial two-speed motor, Model 5011, 21,000 RPM, as illustrated in Figure 1.
• Threshed burley tobacco ste shards up to approximately three inches in length are softened by moistening to over 60% moisture content and held or "bulked" for one hour in a sealed
• the softened stems are Waring Blendor shredded in 10 g ' batches for 30 seconds each.
• a fraction of the shredded product which passes through a standard Sweco 4-mesh screen and retained on a 30-mesh Sweco screen is dried and equilibrated under standard conditions in air of 60% relative humidity at 75 F.
• the shredded stems so equilibrated exhibit a cylinder volume of 92 cc for a weight of 10 g at 12.6% OV (oven volatiles) compared to burley stems prepared by the usual rolling and cutting process which exhibit a cylinder volume of 49 cc for a like weight with 12.5% OV.
• a standard one-quart metal Waring Blendor bowl as illus ⁇ trated in Figure 1 is equipped with a vertical rectangular slot of 1 x 3 inches in. one side wall and provided with a height adjustable bottom edge by means of an adjustable closure.
• the bowl is also fitted with a standard blade set and a wide mouth plastic funnel and is powered by a standard commercial two-speed motor, Model 5011, which is capable of turning at 21,000 RPM, as shown in Figure 1.
• Threshed burley stems of up to 3 inches in length are softened by moistening to 65% H O and holding for one hour in a sealed container.
• the softened stems are added slowly at the rate of 5 to 10 g per minute through the funnel 15, and the bottom edge • of the slot 14 is height adjusted by gate element 21 to permit exit of a subjectively optimum fraction of shredded stems.
• a fraction of the product produced as passed through a standard Sweco 4-mesh screen and as further retained on a 30-mesh Sweco screen is dried and equilibrated under standard conditions.
• the shredded stems thus treated exhibit a cylinder volume of 90 cc per 10 g of weight at 12.5% 0V compared to burley stems prepared by the usual rolling and cutting process which exhibit a cylinder volume of 49 cc per 10 g of weight at 12.5% 0V.
• Example 3 Fitzmill Shredding Utilizing a 4-Mesh Exit Screen 5 A Model M Fitzmill equipped to turn at 5,000 RPM is equipped with blunt impact blades of Type D-625 and a 4-mesh exit screen, Type A, No. 4, as shown in Figure 2.
• Threshed burley stems of up to three inches in length are softened by moistening to above 60% moisture and held for one hour 10 in a sealed container.
• the softened stems are passed through the Fitzmill at about five pounds per hour.
• a fraction of the crude shredded stems passing through a slotted Sweco screen with openings of 1% x 3/32 inches and retained on a regular 30-mesh Sweco screen is dried and equilibrated under 15 standard conditions.
• the shredded stems exhibit a cylinder volume of 70 cc per- 10 g of weight at 12.5.% GV compared to 49 cc per 10 g of weight at 12.5% 0V for burley stems prepared by the usual roll ⁇ ing and cutting process.
• Example 3 The process of Example 3 is performed except that a Fitzmill exit screen with -inch round holes is used. Very little shredding action takes place due to the rapid exit of the stems 30 from the vicinity of the rotating blades.
• Example 3 The process of Example 3 is performed except that a Fitzmill exit screen with round holes of 8-mesh is used.
• the crude 35. product exiting the Fitzmill under these conditions is very finely divided with a high proportion of dust and undesirable fines due to an excessive time spent in contact with the rotating blades.
• Example 6 Fitzmill Shredding with a Regular 4-Mesh Classifying Screen The process of Example 3 is performed except that a
• Example 1 The process of Example 1 is performed with bright stems at above 60% moisture content replacing the burley stems.
• the product passing through a 4-mesh and retained on a 30-mesh screen has a cylinder volume of 45 cc per 10 g of weight at 12.5% OV • compared with 36 cc per 10 g.of weight at 12.5% OV for bright stems prepared by the usual rolling and cutting process.
• Example 8
• Example 3 The process of Example 3 is performed with bright stems at above 60% OV replacing the burley stems.
• the passing through a 4-mesh onto a 30-mesh product fraction had a cylinder volume of 43 cc per 10 g of weight at 12.5% OV compared with 36 cc per 10 g of weight at 12.5% 0V for bright stems prepared by the usual roll ⁇ ing and cutting process.
• OMP Th e process of the present invention makes possible the conversion of stems .of both flue-cured and air-cured tobacco into a usable blending component for cigarette filler.
• the final product in the form of fibrillar stem shreds is very well suited for use in cigarette filler blends and offers considerable economic advan ⁇ tages. Moreover, a high capital investment is not required for- the process which can be carried out using readily available equipment.

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• Manufacture Of Tobacco Products (AREA)

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Citations (5)

• 1979
  • 1979-04-12 JP JP50165979A patent/JPS56500478A/ja active Pending
  • 1979-04-12 BR BR7909001A patent/BR7909001A/pt unknown
  • 1979-04-12 WO PCT/US1979/000227 patent/WO1980002101A1/en not_active Ceased
  • 1979-04-12 DE DE19792953627 patent/DE2953627A1/de not_active Withdrawn
  • 1979-04-12 GB GB8039733A patent/GB2059246B/en not_active Expired

Patent Citations (5)

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