CA2317561C - Tobacco drying apparatus - Google Patents
Tobacco drying apparatus Download PDFInfo
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- CA2317561C CA2317561C CA002317561A CA2317561A CA2317561C CA 2317561 C CA2317561 C CA 2317561C CA 002317561 A CA002317561 A CA 002317561A CA 2317561 A CA2317561 A CA 2317561A CA 2317561 C CA2317561 C CA 2317561C
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Abstract
A high humidity drying apparatus for cut tobacco is shown. The apparatus has a furnace which heats circulated air within the apparatus. The air is forced through a first arcuate elbow which has a tobacco air inlet located thereon for inserting th e cut tobacco into the airstream. The tobacco is then redirected into a vertically extending drying chamber. The ~~separation of removing one tobacco from the heated air. The separator has dual air exhausts, each leading to a high efficiency cyclone for further removal of the tobacco dust form the circulated air. All of the air is then passed back to the furnace for heating and then recirculated through the drying apparatus.
Description
~'&K833-02-00 TOBACCO DRYING APPARATUS
TECWNTCAL FIELD
S The present invention relates to ati apparatus for drying cut tobacco and more particularly to an apparatus for drying tobacco under relatively high humidity dxying conditions.
BACKGROUND OF TTY rN'VENTION
In the manufacture of cigarettes and like articles, it is the usual practice co reduce tobacco, the term being used herein to include both lamina and stems, to a panicle size appropriate for manufacturing cigarettes. Tl~e moisture content of the tobacco is generally increased prior to this size reduction processing in order to mixziutnize tobacco breakup and provide a material of uniform particle size. Furthermore, in order' to process the treated tobacco tat the manufacturing of cigarette rods, it is necessary to reduce the l~aoisturc content of the tobacco to a level below that which the tobacco is at after treatment by casings, flavorings and other additives. The actual drying process has a direct impact upon the quality of tobacco utilized during cigarette manufacturing because of the effect the drying process has upon the tobacco material itself.
Additionally, drying of tobacco after the addition of flavorings and casinbs has a direct impact upon the quality of the tobacco itself. Tt; during drying, the tobacco is subjected to rigorous agitation or contact with stationary surfaces, the tobacco material ea~a be damaged by breakup thus decreasing the tilling capacity of the tobacco. This unwanted result is also acliieved when drying under low humidity conditions. It is therefore necessary to dry the moist tobacco under high humidity conditions while also preveneing damaging contact to the tobacco material.
3U U.S. Patent No. 4,167,191 teaches a pmcess for high humidity drying of tobacco m~.~terial in order to reduce the moisture content of expanded tobacco while mizktxaizzng yield losses and NddC833-UZ-UO
reducing particle lamination while maintaining filling power. The air temperaitu'e. used to dry the tobacco is within a range of around 250EF(121.1Ef~ to about 65UEF(343_2EC) in the presence of an absolute hutxtidity at a Ieve1 above that which will provide a wet-bulb temperature reading of at least about 1 SiIEF(65.6EC), U_S_ Patent No. 4,315,51. S teaches a tobacco drying apparatus having a pluraEity of expansion chambers which cffcxt a drying of the tobacco within a high humidity environment The drying chambers are utilized to reduce the velocity of the air flow through tlt~e apparatus as well as a dryer means do effect drying of the air entrained tobaveo to the desirod moisture level. However, the apparatus requires long extensions of air ducting as well as several air redirection areas or elbows which cause the ~tobac;co to come into contact with the walls of the ducts tux the air chambers causing tobacco breakup, sanitfuy, cleaning and other problems within the apparatus.
SUMMARY OF THE iNVENT1(aN
The present inverilion is for a high humidity tobacco drying apparatus and more particularly a high humidity cut tobacco drying apparatus which requires minimal residence time of the cut tobacco in the drying and expansion chamber.
Mon particularly, the present invention eoxnprisos a heated air intake duct which provides air at a predetermined temperature and humidity level. The air intake duct enters into a tlrst arcuate elbow wherein cut tobacco is mixed in the high velocity heated air by an upwardly extending trapezoidal inlet The first arcuate elbow rCdirects the air flow from a horizontal airflow to a vertical airflow. The outer wall of the intcsrior first elbow has a water cooled door which opens outwardly for access to the interior of said drying apparatus. Tha first elbow redirects tfte tobacco eatraiztCd air~ow vcrticaiiy ixttb a tong verricaiiy extending drying and expansion chamber. The vertically extending drying chamber Cnds at a second elbow which redirects the siz~l.ow into a tangential separator. The second elbow also has a water cooled door on the interior outer wall thereby preventing buildup of casings and other materials on the interior surface of the elbow. The tangential separator provides a means for F8tKa33-02-00 removing the cut tobacco from the high velocity air stream by reducing the velocity of the airflow and allowing the tobacco entrained therein to fall out of the airstream and into a rotary airlock. The heated air stream exits the separator frottt both side walls of the tangential separator, eacli of said exhausts ezttCriztg a high efficiency cyclone for further separation sad removal of any tobacco matexial remaining tux the aurstream_ Finally, the preset inv~tion comprises a high humidity drying apparatus for drying out tobacco, comprising: a longitudinally extending bested air intake duct; a first a~iate elbow in flow communication with said intake duct and having a downward preselected angle of I O eurvatute;, said first elbow having a hinged water-cooled door on an outer wall; an upwardly extending tobacco inlet of trapezaidal crass-section in flow communication with said first elbow, said upwardly extending tobacco inlet formed an said first elbow at a point vsihere the vertical expansion of the Fu~t areuate elbow begins; a verti~lly extending drying chamber in flow aammunication with said first elbow; a second arcuatc elbow in flaw communication with said vertically extending drying chamber said second elbow having a binged water cooled door on any outer wall; a tangential separator in flow communication with said sccox~d elbow, said separator having a tobaeca outlet airlock, said separator also having a first and a second centrally alignod perpendicular air exhaust on opposed sides, said first air exhaust being in flow communication with a first high off cieney cyclone and said second air exhaust izx flow communication with a second high effici~.~nCy cyclone.
BRIEF DESCRi~TION Ol~ 'rFIE DRAWINGS
A better understanding of the invention will be had upon reference to thc~
followuig description in conjunction with the accompanying drawings in which like numorals refer to like parts and wherein:
Fig. 1 is a side view of a high humidity drying apparatus of the present invention;
Fig. 2 is a fmnt view of a vertically extending drying and expansion chamber of Fig.
F&KA33-02-QO
1.;
Fig. 3 is a perspective view of the tangential separator, the two air exhausts and the lust and second high eff cicncy cyclone of Fig. 1;
Fig. 4 is a perspective view of the tobacco inlet area;
Fil;. 5 is a side view of the water cooled door on the first arcuale elbow;
Fig. 6 is a side view of the water cooled door on the second arcuate elbow;
Fig. 7 is a side view of the tangartial separator and the watcx cooled door of its upper edge; and, Fig. 8 is a cut away bottom view of the vertically extending drying and expansion chamber of Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
~0 As shown in Figure 1, a high humidity drying apparatus 1 U of the present invention is cot~aprisGd of multiple duct section.R L 1, 14, 20, 26 and 30. Air far use in the apparatu.R 10 is heated is a furnace (not shown). The circulated air, after heating, is raised to an appropriate moisture level to create high humidity drying conditions. Moisture is added by injecting stcayn into tbc air stream in order to raise the moisture level of the circulated heated air to the appropriate level. This also serves to raise the ttmperriurc of the circulated air within the dxyaz~.g apparatus itself. The moisture level of the airstream is closely monitored in order to provide a wet-bulb temperature of, for example, at least about 210EF(98.9EC) as that term is defined in ~U'. S. Patent No. 4,167,191.
i A heated air inlet 15 receives the air from the furnace at a relatively high velocity such as, for F&K~333-U2-00 example, from 5,000( 1523.9 rtt) to about 8,000(2438.4 m)fa;t per minute. A
heated air intake duct 11 is disposed in flow communication with and downstream from inlet 15 with expansion joints 17a and 17b being provided to allow for the heated air intakC
duct 11 to cxpattd and contract as the air is passed therethrough. The heated sir intake duct 11 has a height of about 18 inches and a width or depth of about 66 inches(167.5 cm.).
The average air temperaiute at the heatod air intake duct 11 is generally maitttaincd at around 3fi0EF(182.2EC). The sir in the heated aix intake duct 11 has a velocity of, for example, about 6300 ft.(1920.2 m~min. as it is accelerated into a narrow entry throat 19 of first arcuate elbow 14.
IO
The entry throat 19 of first arcuate elbow 14 is tapered inwardly thereby providing f-u'st arcuate elbow 14 with an inner diameter less than heated air intake duct 11.
Heated air intake duct t 1, as shown in Figure 1, has a downward angle of appxoxirna.tely about 12 to 13 does front horizontal before fixst elbow 14 toms upwards to redirect the airQow accordingly. After first elbow 14 turns upwards, a trapezoidal inlet airlock 12 is provided aq the means bo add cut tobacco into the airstream. Inlet airlock 12 is generally of a trapezoidal cross-section and is positioned above elbow 14 allowing the tobacco to fall verticalty into the airstream flowing through elbow 14 below airlock 12. Inlet airlock 12 has located therein a rotary airlock 12a, shown i» Figure 4, for incn,~mental addition of thd cut tobacco into the sirslxeam thereby preventing a decr~:ase in the pressure and speed of the airflow therebelow_ The cut tobacco which enters inlet airlock I 2 usually has casings, flavorings and other additives blended therewith and exhibits a tobl maisturc coxttcnt of generally about 21 °/a to 23% by weight. In a preferred operation, cut tobacco is passed through the airlock 12 at a 2S rate of, for example, between about 14,()n0 lb(5350 kg)/hr and about 49,000 lb(22226 kg)Ihr.
As shown in p'igure 1, after narrowing along narrow neck portion 19, elbow 14 is provided with an increasing diamctcx section starring at a position id~~ntifi~d by vertical expansion line 13 at the juncture with the inlet airlock 12. 'this vertical expansion line 13 ,prevents a negative pressure point forming withizt the inlet airlock I2 and expands along the interior angle of curvature of the elbow 14. 'I he incr~sing height of the interior of the Clbow 14 at N.~,1C833-U2-OU
the vertical expansion line 13 of the airlock 12 causes a zero pressure point to form just above the expaztsaon line l 3 of first elbow 14 and within the airlock 12 itself.
This vertical B~>Z~tflB taffftii T ii~a''iIt cX~iinWui°xu~fi'iS i'v auv~C't»'iu"ciias~di:io i;uij l~'idt'v' pressure point within the airlock 12 prevents backflow of the cut tobacco into the airlock and keeps the cut tobacxo flowing info the airseream with minimal buildup of the tobacco in the airlock. A better diagram of the trapezoidal design of the inlet airlock is shown in )~igure 4 withixlt which is located a rotary airlock 12a which incrementally allows tobacco into the airstream flowing #hcrcbelow under high velocity. Cut tobacco enters the airlock from a vibrating conveyor system which pmvidcs the oobacco after fine cutting by a separate cutting apparatus. The cut tobacw bass a moisture content of around 21% to 23% as stated previously. By implementing the widening of the airlock 12 at expansion line 13, the citt tobacco is prevented from bacl~lowing into the airlock which can occur when negative pressure is formed within the airlock chamber. The trapezoidal cross-sectional airlock allows the cut tobacco to be fed into tlxe main aiastreat~a at a relatively high rate of, for exarrtple, approximatxly 30,000 pounds(13608 kg~hour on average: ox greater, without clogging the airlock portion of the drying apgarxtus or oversaturating the airstream.
The overall design of the present invention creates a double null point pressure configuration which is caused directly by the design of the venturi at the tobacco inlet 12_ A first pressure null point is formed just within inlet area 12 co prevent backflow of the tobacco in the tobacco inlet area 12. A second null point is created within tangential separator 30 j ust below tlxc air rxhausts 32 and 36 which exit the separator centrally therein. As stated, this double null point conrguration aids in transporting the cut tobacco through the drying apparatus and ensuring a smooth flow of material throughout the drying apparatus 10.
As shown in Figure 1, first elbow 14 is provided wish a wal;cr cooled exterior door 16.
Water cooled door 16, shown in Figure 5, provides access to the interior of the first elbow 14 of drying apparatus 10. Door 16 is provided with a curved interior outer wall 23 which comes into contact with the cut tobacco and the moist flavorings and casings added thereon.
Chilled water is circulated through the door 16 within interior channels which repeatedly rvrcaaa-oz-oa cross the length of the door 1.6 in back and forth fashion in order to keep a lay~x of condensats moisture on interior outer wall 23 which in turn prevents buildup of the casings and flavorings. These channels are formed in a back and forth direetio:n in order to cover as much surface area of the door 14 as possible. The buildup of material on the outer wall 23 can present hygiene problems as well as reduce the smooth now of tobacco material which comes into contact with the interior outer wall 23- By passing chilled water through interior pipes of the door 16, a condensation layer is created on interior outer wall 23 which allows the cut tobacco to come into contact with the layer of moisturs on the wall preventing deposits of any of the casings or flavorings on the interior of the drying apparatus.
tp Water cooled door 16 is also attached Lo air cylinder 25 which allows the dour to be opened and closed. Door 16 is hinged at point 27 to facilitate: the opening and closing action. While interior outer wall 23 of door 16 is curved, a fiat contact surface 25 is utilized in order to provide a flat smooth sealing surface. This flat contact surface 25 allows proper sealing of the door 16 onto elbow 14 while still providing a hinged access point into the apparatus. By providing water cooled door 16, buildup on the interior outer wall 23 is kept to a minimal level and access is provided into the interior of the drying apparatus for inspection and cleaning when required.
ltetuming to Figure 1, downstream from fiiait arcuate elbow 14 is vertically extending drying and expansion chamber 20. And, as best shown in Fignre 2 at the dowx~strc~m terminating end of f rst elbow as identified by the numeral 1 R marks the beginning of the expansion of the interior of the drying chamber, Vertical drying channber 20 extends upwards genera3ly about, for example, 42 feet(12.$ m) to 60 feet (18.3 m) to provide adequate distance and drying tirtxe fox the cut tobacco. In order to dry the cut tobacco to the appropriate moisture level, tobacco eatrainad within the airslream will remain in the drying chamber 20 until it reaches a predetermined moisture content, usually for example, about 13% to 15% by weight. If the moisture content of the tobacco is too high, the tobacco will lx. too heavy to rise to the second elbow 26. In addition, to ensure the proper flow of tobacco within the apparatus and especially in the vertical drying and expansion chamber 20, the walls of the vertical drying chamber 20 are rounded at the comers of the chamber, as shown in Figure 8, to prevent FI~K833-02-00 contact of the moist tobacco with the interior ducts of the drying apparatus thereby causing airflow or liygiene problems. Tlvs ctu'vcd or circular design promotes a smooth airflow through the drying apparatus 10 by removing the 90E corners where circulating air tray slagnatc and lessen tobacco flow capability. Typically, within the comers of the ducting, airflow tends to stagnate or become less active thereby preventing the proper flow of the tobacco entrained within the air.
Downstream of the vertical drying chamber 20 and in flow communication therewith is second arcuate elbow 26 which, as with first elbow 14, is fitted with an outwardly oxtending water cooled door 24. Second elbow 26 is disposed to redirect the air entrained tobacco from the vertical direction to horizoni<~.1. Second elbow door 24 baing water cooled as is th.e first elbow door 16, prevents buildup of material on outer interior wall surface 31 &hown in Figure 6. This watxsr which is passed through the interior of the door 24, as with first elbow door 16, is kept at a controlled temperature of, far example, about 190EF(87.8EC). This temperature is optimal in that it is approxita7ately 20EF(-6.67EC). below the appropriate wet bulb temperature of the tobaoeo. A fine condensation layer of water is thus formed on the int~crior elbow wall 31 allowing the tobacco entrained within the airflow to conbct wall 31 without leaving residuo on the inner ducts of the drying apparatus. Door 24 is also hinged at a point identified by numeral 29 and has au air cylinder 33 attached thereto which provides means to raise and lower the door 24.
Downstream from aztd in flow communication with second areuate elbow 26 is tangential sGptual~Vr 30 which iu Lutu is iu auw i:ouuuu,uicatiott wiiii duct high cfLicivuvy uyulm~ ~i0 and 42. As stated previously, the airflow velocity within the drying apparatus is maintained at, for example, about 6300 R(1920 m~min. 1n order to remove the tobacco from the high velocity airstream, the tangential separator 30 forces the tobacco against an interior surface or wall 39 of hinged water Cooled door 38 shown in Figure 7. This reduces the velocity of the out mbacco so that it can be removed front the airJ:7aw. And, chilled water flows through the interior of hinged door 38 in order to prevent buildup of material oa interior sur~ce wall 39.
The velocity of the airflow within the drying apparatus 10 is reduced as it circulates around the interior of tangential separator 30 thereby allowing, the cut tobacco to Fall into rotary F8cK833-(Y1-00 airlock 34. As shown in Figure 3, the heaeed air is exhausted through dual sir exhaust exit ducts 32 and 36 whsle the majority ofthe dried tobacco drops out of the airstream and talc the rotary airlock 34 for further processing. Each air exhaust 32 and 36 aro centrally aligned an on opposite sides of the tangentiai separator and remove air from the separator 30 through a multi-vane rotary exhaust located centrally within separator 3U. Each of the air exhausts 32 and 36 lead to cyclones for the further r~noval of the cut tobacco from the circulated air stream. Exhaust from the separator must be properly balanced to each of the exhausts exit lines 32 and 36 so that the proper airflow is exhibited within the drier to prevent buildup of material in the second elbow 26. The ratio between the drying chamber 22 and the transition leading to the separator 3$a, as shown i11 FigurC 1, is approximately 0.4.
A socond zero pressure point is formed within the drying apparatus in the tangential separator 30 in order to assist in product removal from the interior ducts of transition area 38a and second elbow area 24. The moistut'e content of the out tobacco at the airlock 34 is reduced to about 15% to 17% moisture content and is elevated to a temperature of about 2'1 OEF(98.9EC).
The air exhausted through ducts 32 and 36 will still have small amounts of tobacco within the airstn"am. To further filter the air and remove this material, high efficiency cyclones 40 and 42 arc provided in order to deposit further tobacco dust and material into removal bins 46 and 48 while allowing the heated air to exhaust through ducts 50 aad 52 and recirculate back into the drying apparatus. The drying apparatus 10 can then utilize this heated air back into the heated air intake duct 11 for processing of additional cut tobacco. The total dwell time of the cut tobacco within the drying apparatus 10 is only about 3 seconds and the moisture content is reduced from about 2I% to 23% to about 15% to 17% in that short amount of time.
Additionally, the drying appan1115 10 reduces breakage of the cut tobacco thereby increasing the filling capacity of the material while also reducing the amount of contact the cut tobacco has with the interior walls of the apparatus. This not only increases the filling capacity of the material but also reduces the maintenance costs of the drying apparatus as the interior does riot rexluire extensive and continuous cleaning. To prevent fitxther deposits of tobaeCO easing and flavoring material on the interior of the drying apparatus 10 and specifically within the F&K833-Q2-00 tangential separator 30, back wall 39a of the tangential separator is also water cooled to generate a this layer of condensate which buffers the contact of the cut tobacco on the interior walls.
Ex~plc 1 ,A, test run of the new drying apparatus was conducted under the specifications outlined above. The results of the dried cut tobacco were compared with cut tobacco dried in a prior art device such as that dcscnibcd i;a U.S.1'atez~t 4,315,515. The results are shown below. As can be seen, the moisture coat~t of the cut tobacco remained about the same while the tatul drying timeJresident time within the dr~ng apparatus was redtlecd from about 8 seconds to about 3 seconds. The tobacco dried in the drying apparatus of the present invention exhibited a t7auch greater fill value. Moisture from the table is read as the percent wet weight basis.
hill value is dotamiunc~d ix~. oubic centimeters pex graua. Propylene Qlycal is measured ~a percent Particle sip measurcmcnta arc dctcmrincd based upon +9 mesh sievimg process where the value disphtyed is the percentage of particles which have a particle size of +9 or larger. This value is desired to be as large as possible because it is a good indication of the degradation of the tobacco during the drying process. Finally, the -14 particle size measurement determines the percentage of particles under 14 mesh and is desirod to be as small as possible.
F&KA33-02-Op 1'a~~ 11 )?xo a P ccs Tnlcl er E il er Percent t'.:hanac Average Av_ erase Moisture Moisture Moisture Existing 21.8 14.4 NIA
blew 22_ 1 13.5 Fill-Value Existing 4.73 5.03 -~-6 New 4, $4 5.41 +12 Propylt.ne Existins 0.58 0.49 -t 6 ~xlycol New 0.59 0.57 -3 +9 ParticleExisting 77.fi 73.7 -5 Size New 72.9 70.G -3 -14 ParticleExisting 6.S 9.1 +40 size New 8.4 10.8 +28 'Z'he forcgoixxg det~ilcd description is given primarily for clearness of understanding and no S unnecessary linlilations arc Lo be untit.'rstcx~d therefrom for modifications will beoorne obvirn~s to those skilled in the art upon jading this disclosure find may be made without departing from the spirit of the invention or the scope of the appended clai~ds.
TECWNTCAL FIELD
S The present invention relates to ati apparatus for drying cut tobacco and more particularly to an apparatus for drying tobacco under relatively high humidity dxying conditions.
BACKGROUND OF TTY rN'VENTION
In the manufacture of cigarettes and like articles, it is the usual practice co reduce tobacco, the term being used herein to include both lamina and stems, to a panicle size appropriate for manufacturing cigarettes. Tl~e moisture content of the tobacco is generally increased prior to this size reduction processing in order to mixziutnize tobacco breakup and provide a material of uniform particle size. Furthermore, in order' to process the treated tobacco tat the manufacturing of cigarette rods, it is necessary to reduce the l~aoisturc content of the tobacco to a level below that which the tobacco is at after treatment by casings, flavorings and other additives. The actual drying process has a direct impact upon the quality of tobacco utilized during cigarette manufacturing because of the effect the drying process has upon the tobacco material itself.
Additionally, drying of tobacco after the addition of flavorings and casinbs has a direct impact upon the quality of the tobacco itself. Tt; during drying, the tobacco is subjected to rigorous agitation or contact with stationary surfaces, the tobacco material ea~a be damaged by breakup thus decreasing the tilling capacity of the tobacco. This unwanted result is also acliieved when drying under low humidity conditions. It is therefore necessary to dry the moist tobacco under high humidity conditions while also preveneing damaging contact to the tobacco material.
3U U.S. Patent No. 4,167,191 teaches a pmcess for high humidity drying of tobacco m~.~terial in order to reduce the moisture content of expanded tobacco while mizktxaizzng yield losses and NddC833-UZ-UO
reducing particle lamination while maintaining filling power. The air temperaitu'e. used to dry the tobacco is within a range of around 250EF(121.1Ef~ to about 65UEF(343_2EC) in the presence of an absolute hutxtidity at a Ieve1 above that which will provide a wet-bulb temperature reading of at least about 1 SiIEF(65.6EC), U_S_ Patent No. 4,315,51. S teaches a tobacco drying apparatus having a pluraEity of expansion chambers which cffcxt a drying of the tobacco within a high humidity environment The drying chambers are utilized to reduce the velocity of the air flow through tlt~e apparatus as well as a dryer means do effect drying of the air entrained tobaveo to the desirod moisture level. However, the apparatus requires long extensions of air ducting as well as several air redirection areas or elbows which cause the ~tobac;co to come into contact with the walls of the ducts tux the air chambers causing tobacco breakup, sanitfuy, cleaning and other problems within the apparatus.
SUMMARY OF THE iNVENT1(aN
The present inverilion is for a high humidity tobacco drying apparatus and more particularly a high humidity cut tobacco drying apparatus which requires minimal residence time of the cut tobacco in the drying and expansion chamber.
Mon particularly, the present invention eoxnprisos a heated air intake duct which provides air at a predetermined temperature and humidity level. The air intake duct enters into a tlrst arcuate elbow wherein cut tobacco is mixed in the high velocity heated air by an upwardly extending trapezoidal inlet The first arcuate elbow rCdirects the air flow from a horizontal airflow to a vertical airflow. The outer wall of the intcsrior first elbow has a water cooled door which opens outwardly for access to the interior of said drying apparatus. Tha first elbow redirects tfte tobacco eatraiztCd air~ow vcrticaiiy ixttb a tong verricaiiy extending drying and expansion chamber. The vertically extending drying chamber Cnds at a second elbow which redirects the siz~l.ow into a tangential separator. The second elbow also has a water cooled door on the interior outer wall thereby preventing buildup of casings and other materials on the interior surface of the elbow. The tangential separator provides a means for F8tKa33-02-00 removing the cut tobacco from the high velocity air stream by reducing the velocity of the airflow and allowing the tobacco entrained therein to fall out of the airstream and into a rotary airlock. The heated air stream exits the separator frottt both side walls of the tangential separator, eacli of said exhausts ezttCriztg a high efficiency cyclone for further separation sad removal of any tobacco matexial remaining tux the aurstream_ Finally, the preset inv~tion comprises a high humidity drying apparatus for drying out tobacco, comprising: a longitudinally extending bested air intake duct; a first a~iate elbow in flow communication with said intake duct and having a downward preselected angle of I O eurvatute;, said first elbow having a hinged water-cooled door on an outer wall; an upwardly extending tobacco inlet of trapezaidal crass-section in flow communication with said first elbow, said upwardly extending tobacco inlet formed an said first elbow at a point vsihere the vertical expansion of the Fu~t areuate elbow begins; a verti~lly extending drying chamber in flow aammunication with said first elbow; a second arcuatc elbow in flaw communication with said vertically extending drying chamber said second elbow having a binged water cooled door on any outer wall; a tangential separator in flow communication with said sccox~d elbow, said separator having a tobaeca outlet airlock, said separator also having a first and a second centrally alignod perpendicular air exhaust on opposed sides, said first air exhaust being in flow communication with a first high off cieney cyclone and said second air exhaust izx flow communication with a second high effici~.~nCy cyclone.
BRIEF DESCRi~TION Ol~ 'rFIE DRAWINGS
A better understanding of the invention will be had upon reference to thc~
followuig description in conjunction with the accompanying drawings in which like numorals refer to like parts and wherein:
Fig. 1 is a side view of a high humidity drying apparatus of the present invention;
Fig. 2 is a fmnt view of a vertically extending drying and expansion chamber of Fig.
F&KA33-02-QO
1.;
Fig. 3 is a perspective view of the tangential separator, the two air exhausts and the lust and second high eff cicncy cyclone of Fig. 1;
Fig. 4 is a perspective view of the tobacco inlet area;
Fil;. 5 is a side view of the water cooled door on the first arcuale elbow;
Fig. 6 is a side view of the water cooled door on the second arcuate elbow;
Fig. 7 is a side view of the tangartial separator and the watcx cooled door of its upper edge; and, Fig. 8 is a cut away bottom view of the vertically extending drying and expansion chamber of Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
~0 As shown in Figure 1, a high humidity drying apparatus 1 U of the present invention is cot~aprisGd of multiple duct section.R L 1, 14, 20, 26 and 30. Air far use in the apparatu.R 10 is heated is a furnace (not shown). The circulated air, after heating, is raised to an appropriate moisture level to create high humidity drying conditions. Moisture is added by injecting stcayn into tbc air stream in order to raise the moisture level of the circulated heated air to the appropriate level. This also serves to raise the ttmperriurc of the circulated air within the dxyaz~.g apparatus itself. The moisture level of the airstream is closely monitored in order to provide a wet-bulb temperature of, for example, at least about 210EF(98.9EC) as that term is defined in ~U'. S. Patent No. 4,167,191.
i A heated air inlet 15 receives the air from the furnace at a relatively high velocity such as, for F&K~333-U2-00 example, from 5,000( 1523.9 rtt) to about 8,000(2438.4 m)fa;t per minute. A
heated air intake duct 11 is disposed in flow communication with and downstream from inlet 15 with expansion joints 17a and 17b being provided to allow for the heated air intakC
duct 11 to cxpattd and contract as the air is passed therethrough. The heated sir intake duct 11 has a height of about 18 inches and a width or depth of about 66 inches(167.5 cm.).
The average air temperaiute at the heatod air intake duct 11 is generally maitttaincd at around 3fi0EF(182.2EC). The sir in the heated aix intake duct 11 has a velocity of, for example, about 6300 ft.(1920.2 m~min. as it is accelerated into a narrow entry throat 19 of first arcuate elbow 14.
IO
The entry throat 19 of first arcuate elbow 14 is tapered inwardly thereby providing f-u'st arcuate elbow 14 with an inner diameter less than heated air intake duct 11.
Heated air intake duct t 1, as shown in Figure 1, has a downward angle of appxoxirna.tely about 12 to 13 does front horizontal before fixst elbow 14 toms upwards to redirect the airQow accordingly. After first elbow 14 turns upwards, a trapezoidal inlet airlock 12 is provided aq the means bo add cut tobacco into the airstream. Inlet airlock 12 is generally of a trapezoidal cross-section and is positioned above elbow 14 allowing the tobacco to fall verticalty into the airstream flowing through elbow 14 below airlock 12. Inlet airlock 12 has located therein a rotary airlock 12a, shown i» Figure 4, for incn,~mental addition of thd cut tobacco into the sirslxeam thereby preventing a decr~:ase in the pressure and speed of the airflow therebelow_ The cut tobacco which enters inlet airlock I 2 usually has casings, flavorings and other additives blended therewith and exhibits a tobl maisturc coxttcnt of generally about 21 °/a to 23% by weight. In a preferred operation, cut tobacco is passed through the airlock 12 at a 2S rate of, for example, between about 14,()n0 lb(5350 kg)/hr and about 49,000 lb(22226 kg)Ihr.
As shown in p'igure 1, after narrowing along narrow neck portion 19, elbow 14 is provided with an increasing diamctcx section starring at a position id~~ntifi~d by vertical expansion line 13 at the juncture with the inlet airlock 12. 'this vertical expansion line 13 ,prevents a negative pressure point forming withizt the inlet airlock I2 and expands along the interior angle of curvature of the elbow 14. 'I he incr~sing height of the interior of the Clbow 14 at N.~,1C833-U2-OU
the vertical expansion line 13 of the airlock 12 causes a zero pressure point to form just above the expaztsaon line l 3 of first elbow 14 and within the airlock 12 itself.
This vertical B~>Z~tflB taffftii T ii~a''iIt cX~iinWui°xu~fi'iS i'v auv~C't»'iu"ciias~di:io i;uij l~'idt'v' pressure point within the airlock 12 prevents backflow of the cut tobacco into the airlock and keeps the cut tobacxo flowing info the airseream with minimal buildup of the tobacco in the airlock. A better diagram of the trapezoidal design of the inlet airlock is shown in )~igure 4 withixlt which is located a rotary airlock 12a which incrementally allows tobacco into the airstream flowing #hcrcbelow under high velocity. Cut tobacco enters the airlock from a vibrating conveyor system which pmvidcs the oobacco after fine cutting by a separate cutting apparatus. The cut tobacw bass a moisture content of around 21% to 23% as stated previously. By implementing the widening of the airlock 12 at expansion line 13, the citt tobacco is prevented from bacl~lowing into the airlock which can occur when negative pressure is formed within the airlock chamber. The trapezoidal cross-sectional airlock allows the cut tobacco to be fed into tlxe main aiastreat~a at a relatively high rate of, for exarrtple, approximatxly 30,000 pounds(13608 kg~hour on average: ox greater, without clogging the airlock portion of the drying apgarxtus or oversaturating the airstream.
The overall design of the present invention creates a double null point pressure configuration which is caused directly by the design of the venturi at the tobacco inlet 12_ A first pressure null point is formed just within inlet area 12 co prevent backflow of the tobacco in the tobacco inlet area 12. A second null point is created within tangential separator 30 j ust below tlxc air rxhausts 32 and 36 which exit the separator centrally therein. As stated, this double null point conrguration aids in transporting the cut tobacco through the drying apparatus and ensuring a smooth flow of material throughout the drying apparatus 10.
As shown in Figure 1, first elbow 14 is provided wish a wal;cr cooled exterior door 16.
Water cooled door 16, shown in Figure 5, provides access to the interior of the first elbow 14 of drying apparatus 10. Door 16 is provided with a curved interior outer wall 23 which comes into contact with the cut tobacco and the moist flavorings and casings added thereon.
Chilled water is circulated through the door 16 within interior channels which repeatedly rvrcaaa-oz-oa cross the length of the door 1.6 in back and forth fashion in order to keep a lay~x of condensats moisture on interior outer wall 23 which in turn prevents buildup of the casings and flavorings. These channels are formed in a back and forth direetio:n in order to cover as much surface area of the door 14 as possible. The buildup of material on the outer wall 23 can present hygiene problems as well as reduce the smooth now of tobacco material which comes into contact with the interior outer wall 23- By passing chilled water through interior pipes of the door 16, a condensation layer is created on interior outer wall 23 which allows the cut tobacco to come into contact with the layer of moisturs on the wall preventing deposits of any of the casings or flavorings on the interior of the drying apparatus.
tp Water cooled door 16 is also attached Lo air cylinder 25 which allows the dour to be opened and closed. Door 16 is hinged at point 27 to facilitate: the opening and closing action. While interior outer wall 23 of door 16 is curved, a fiat contact surface 25 is utilized in order to provide a flat smooth sealing surface. This flat contact surface 25 allows proper sealing of the door 16 onto elbow 14 while still providing a hinged access point into the apparatus. By providing water cooled door 16, buildup on the interior outer wall 23 is kept to a minimal level and access is provided into the interior of the drying apparatus for inspection and cleaning when required.
ltetuming to Figure 1, downstream from fiiait arcuate elbow 14 is vertically extending drying and expansion chamber 20. And, as best shown in Fignre 2 at the dowx~strc~m terminating end of f rst elbow as identified by the numeral 1 R marks the beginning of the expansion of the interior of the drying chamber, Vertical drying channber 20 extends upwards genera3ly about, for example, 42 feet(12.$ m) to 60 feet (18.3 m) to provide adequate distance and drying tirtxe fox the cut tobacco. In order to dry the cut tobacco to the appropriate moisture level, tobacco eatrainad within the airslream will remain in the drying chamber 20 until it reaches a predetermined moisture content, usually for example, about 13% to 15% by weight. If the moisture content of the tobacco is too high, the tobacco will lx. too heavy to rise to the second elbow 26. In addition, to ensure the proper flow of tobacco within the apparatus and especially in the vertical drying and expansion chamber 20, the walls of the vertical drying chamber 20 are rounded at the comers of the chamber, as shown in Figure 8, to prevent FI~K833-02-00 contact of the moist tobacco with the interior ducts of the drying apparatus thereby causing airflow or liygiene problems. Tlvs ctu'vcd or circular design promotes a smooth airflow through the drying apparatus 10 by removing the 90E corners where circulating air tray slagnatc and lessen tobacco flow capability. Typically, within the comers of the ducting, airflow tends to stagnate or become less active thereby preventing the proper flow of the tobacco entrained within the air.
Downstream of the vertical drying chamber 20 and in flow communication therewith is second arcuate elbow 26 which, as with first elbow 14, is fitted with an outwardly oxtending water cooled door 24. Second elbow 26 is disposed to redirect the air entrained tobacco from the vertical direction to horizoni<~.1. Second elbow door 24 baing water cooled as is th.e first elbow door 16, prevents buildup of material on outer interior wall surface 31 &hown in Figure 6. This watxsr which is passed through the interior of the door 24, as with first elbow door 16, is kept at a controlled temperature of, far example, about 190EF(87.8EC). This temperature is optimal in that it is approxita7ately 20EF(-6.67EC). below the appropriate wet bulb temperature of the tobaoeo. A fine condensation layer of water is thus formed on the int~crior elbow wall 31 allowing the tobacco entrained within the airflow to conbct wall 31 without leaving residuo on the inner ducts of the drying apparatus. Door 24 is also hinged at a point identified by numeral 29 and has au air cylinder 33 attached thereto which provides means to raise and lower the door 24.
Downstream from aztd in flow communication with second areuate elbow 26 is tangential sGptual~Vr 30 which iu Lutu is iu auw i:ouuuu,uicatiott wiiii duct high cfLicivuvy uyulm~ ~i0 and 42. As stated previously, the airflow velocity within the drying apparatus is maintained at, for example, about 6300 R(1920 m~min. 1n order to remove the tobacco from the high velocity airstream, the tangential separator 30 forces the tobacco against an interior surface or wall 39 of hinged water Cooled door 38 shown in Figure 7. This reduces the velocity of the out mbacco so that it can be removed front the airJ:7aw. And, chilled water flows through the interior of hinged door 38 in order to prevent buildup of material oa interior sur~ce wall 39.
The velocity of the airflow within the drying apparatus 10 is reduced as it circulates around the interior of tangential separator 30 thereby allowing, the cut tobacco to Fall into rotary F8cK833-(Y1-00 airlock 34. As shown in Figure 3, the heaeed air is exhausted through dual sir exhaust exit ducts 32 and 36 whsle the majority ofthe dried tobacco drops out of the airstream and talc the rotary airlock 34 for further processing. Each air exhaust 32 and 36 aro centrally aligned an on opposite sides of the tangentiai separator and remove air from the separator 30 through a multi-vane rotary exhaust located centrally within separator 3U. Each of the air exhausts 32 and 36 lead to cyclones for the further r~noval of the cut tobacco from the circulated air stream. Exhaust from the separator must be properly balanced to each of the exhausts exit lines 32 and 36 so that the proper airflow is exhibited within the drier to prevent buildup of material in the second elbow 26. The ratio between the drying chamber 22 and the transition leading to the separator 3$a, as shown i11 FigurC 1, is approximately 0.4.
A socond zero pressure point is formed within the drying apparatus in the tangential separator 30 in order to assist in product removal from the interior ducts of transition area 38a and second elbow area 24. The moistut'e content of the out tobacco at the airlock 34 is reduced to about 15% to 17% moisture content and is elevated to a temperature of about 2'1 OEF(98.9EC).
The air exhausted through ducts 32 and 36 will still have small amounts of tobacco within the airstn"am. To further filter the air and remove this material, high efficiency cyclones 40 and 42 arc provided in order to deposit further tobacco dust and material into removal bins 46 and 48 while allowing the heated air to exhaust through ducts 50 aad 52 and recirculate back into the drying apparatus. The drying apparatus 10 can then utilize this heated air back into the heated air intake duct 11 for processing of additional cut tobacco. The total dwell time of the cut tobacco within the drying apparatus 10 is only about 3 seconds and the moisture content is reduced from about 2I% to 23% to about 15% to 17% in that short amount of time.
Additionally, the drying appan1115 10 reduces breakage of the cut tobacco thereby increasing the filling capacity of the material while also reducing the amount of contact the cut tobacco has with the interior walls of the apparatus. This not only increases the filling capacity of the material but also reduces the maintenance costs of the drying apparatus as the interior does riot rexluire extensive and continuous cleaning. To prevent fitxther deposits of tobaeCO easing and flavoring material on the interior of the drying apparatus 10 and specifically within the F&K833-Q2-00 tangential separator 30, back wall 39a of the tangential separator is also water cooled to generate a this layer of condensate which buffers the contact of the cut tobacco on the interior walls.
Ex~plc 1 ,A, test run of the new drying apparatus was conducted under the specifications outlined above. The results of the dried cut tobacco were compared with cut tobacco dried in a prior art device such as that dcscnibcd i;a U.S.1'atez~t 4,315,515. The results are shown below. As can be seen, the moisture coat~t of the cut tobacco remained about the same while the tatul drying timeJresident time within the dr~ng apparatus was redtlecd from about 8 seconds to about 3 seconds. The tobacco dried in the drying apparatus of the present invention exhibited a t7auch greater fill value. Moisture from the table is read as the percent wet weight basis.
hill value is dotamiunc~d ix~. oubic centimeters pex graua. Propylene Qlycal is measured ~a percent Particle sip measurcmcnta arc dctcmrincd based upon +9 mesh sievimg process where the value disphtyed is the percentage of particles which have a particle size of +9 or larger. This value is desired to be as large as possible because it is a good indication of the degradation of the tobacco during the drying process. Finally, the -14 particle size measurement determines the percentage of particles under 14 mesh and is desirod to be as small as possible.
F&KA33-02-Op 1'a~~ 11 )?xo a P ccs Tnlcl er E il er Percent t'.:hanac Average Av_ erase Moisture Moisture Moisture Existing 21.8 14.4 NIA
blew 22_ 1 13.5 Fill-Value Existing 4.73 5.03 -~-6 New 4, $4 5.41 +12 Propylt.ne Existins 0.58 0.49 -t 6 ~xlycol New 0.59 0.57 -3 +9 ParticleExisting 77.fi 73.7 -5 Size New 72.9 70.G -3 -14 ParticleExisting 6.S 9.1 +40 size New 8.4 10.8 +28 'Z'he forcgoixxg det~ilcd description is given primarily for clearness of understanding and no S unnecessary linlilations arc Lo be untit.'rstcx~d therefrom for modifications will beoorne obvirn~s to those skilled in the art upon jading this disclosure find may be made without departing from the spirit of the invention or the scope of the appended clai~ds.
Claims (43)
1. A high humidity drying apparatus for drying cut tobacco, comprising:
a longitudinally extending heated sir intake duct;
a first arcuate elbow in flow communication with said intake duct, said first elbow having a hinged water-cooled door on an outer wall and having a vertical expansion line formed along the interior angle of curvature of said elbow;
an upwardly extending tobacco inlet of trapezoidal cross-section in flow communication with said first elbow, said upwardly extending inlet formed on said first elbow at a point where a vertical expansion of said elbow begins;
a vertically extending drying chamber in flow communication with said first elbow;
a second arcuate elbow in flow communication with said vertically extending drying chamber said second elbow having a hinged water cooled door on an outer wall;
a tangential separator in flow communication with said second elbow, said separator having a tobacco outlet airlock, said separator also having at least one air exhaust; and at least one high efficiency cyclone in flow communication with said at least one air exhaust of said tangential separator.
a longitudinally extending heated sir intake duct;
a first arcuate elbow in flow communication with said intake duct, said first elbow having a hinged water-cooled door on an outer wall and having a vertical expansion line formed along the interior angle of curvature of said elbow;
an upwardly extending tobacco inlet of trapezoidal cross-section in flow communication with said first elbow, said upwardly extending inlet formed on said first elbow at a point where a vertical expansion of said elbow begins;
a vertically extending drying chamber in flow communication with said first elbow;
a second arcuate elbow in flow communication with said vertically extending drying chamber said second elbow having a hinged water cooled door on an outer wall;
a tangential separator in flow communication with said second elbow, said separator having a tobacco outlet airlock, said separator also having at least one air exhaust; and at least one high efficiency cyclone in flow communication with said at least one air exhaust of said tangential separator.
2. The apparatus of claim 1 wherein said tobacco has a moisture content at said outlet airlock in said tangential separator of from about 13% to 15% by weight.
3. The apparatus of claim 1 wherein the air temperature in said apparatus is maintained at from about 320 (160EC) to about 420 (215.6EC) degrees F.
4. The apparatus of claim 1 wherein said tobacco has a moisture content at said tobacco inlet of from about 21% to 23% by weight.
5. The apparatus of claim 1 wherein the airflow within said apparatus has an average velocity of about 6300 ft(1920 m)/min at said tobacco inlet.
6. The apparatus of claim 1 wherein said longitudinally extending heated air intake duct has a downward preselected angle of curvature.
7. The apparatus of claim 1 wherein said water cooled doors on said first and said second elbows have a plurality of water channels formed therein.
8. The apparatus of claim 1 wherein said outlet airlock within said tangential separator is a rotating airlock.
9. The apparatus of claim 1 wherein said vertically extending drying chamber is about 60 feet(18.29m)in length.
10. The apparatus of claim 1 wherein said tangential separator is further provided with a hinged water cooled door.
11. The apparatus of claim 1 wherein said air exhaust within said tangential separator is a multi-vaned rotary exhaust.
12. The apparatus of claim 1 comprising an interior duct wherein the interior duct comprises rounded corners.
13. The apparatus of claim 1 wherein said air intake duct has a cross sectional width of about 66 inches(167.6cm) and a height of about 18 inches(45.7cm).
14. The apparatus of claim 1 wherein said first arcuate elbow has a vertical expansion line of about 32 inches(81.28cm) to about 27 inches (68.58cm) at said tobacco inlet.
15. The apparatus of claim 1 wherein said apparatus has a zero pressure point within said tobacco inlet and within said tangential separator.
16. The apparatus of claim 1 wherein said at least one air exhaust of said tangential separator is further comprised of a first and a second centrally aligned perpendicular air exhaust on opposed sides, said first air exhaust being in flow communication with a first high efficiency cyclone and said second air exhaust in flow communication with a second high efficiency cyclone.
17. A method for high humidity drying of cut tobacco in a drying apparatus, comprising:
circulating air within a closed drying apparatus;
heating said circulated air in a furnace;
raising the moisture content of said circulated air to a predetermined value of a wet bulb temperature of at least 98.9 degrees C;
adding cut tobacco to said circulated air at a tobacco inlet, said inlet having a rotary airlock located therein;
drying said tobacco under high humidity conditions in a vertically extending drying chamber;
separating said tobacco from said circulated air in a tangential separator;
and, recirculating said air to said furnace.
circulating air within a closed drying apparatus;
heating said circulated air in a furnace;
raising the moisture content of said circulated air to a predetermined value of a wet bulb temperature of at least 98.9 degrees C;
adding cut tobacco to said circulated air at a tobacco inlet, said inlet having a rotary airlock located therein;
drying said tobacco under high humidity conditions in a vertically extending drying chamber;
separating said tobacco from said circulated air in a tangential separator;
and, recirculating said air to said furnace.
18. The method of drying cut tobacco in claim 17 wherein said circulating air has a velocity of about 6300 feet(1920.2m)/minute.
19. The method of drying cut tobacco in claim 17 wherein said heating of said circulated air heats said air to about 360EF(182.2EC).
20. The method of drying cut tobacco in claim 17 wherein said drying chamber extends vertically about 42 feet(12.8m).
21. The method of drying cut tobacco in claim 17 wherein said tobacco residence time in said drying apparatus is 3 seconds.
22. The method of claim 17 wherein said tangential separator has a first and a second air exhaust for exiting said circulated air from said separator.
23. The method of claim 17 further comprising separating tobacco material from said recirculated air after said tangential separator using a high efficiency cyclone.
24. The method of claim 22 wherein said first and said second air exhaust have connected thereto a first and a second cyclone for separating tobacco from said circulated air.
25. The method of claim 17 further comprising forming a layer of moisture condensation along at least one interior elbow of said drying apparatus.
26. A high humidity drying apparatus for drying cut tobacco, comprising:
a longitudinally extending heated air intake duct;
a first elbow in flow communication with said intake duct and having an inlet airlock;
a vertically extending drying chamber in flow communication with said first elbow, said drying chamber having an expanding cross sectional area;
a second elbow in flow communication with said drying chamber; and, a tangential separator in flow communication with said second elbow, said separator having a tobacco outlet airlock.
a longitudinally extending heated air intake duct;
a first elbow in flow communication with said intake duct and having an inlet airlock;
a vertically extending drying chamber in flow communication with said first elbow, said drying chamber having an expanding cross sectional area;
a second elbow in flow communication with said drying chamber; and, a tangential separator in flow communication with said second elbow, said separator having a tobacco outlet airlock.
27. The drying apparatus of claim 26wherein said tangential separator further comprises:
at least one air exhaust; and, at least one high efficiency cyclone in flow communication with said at least one air exhaust of said tangential separator.
at least one air exhaust; and, at least one high efficiency cyclone in flow communication with said at least one air exhaust of said tangential separator.
28. The drying apparatus of claim 26 wherein said first elbow has a hinged water-cooled door on an outer wall.
29. The drying apparatus of claim 26 wherein said second elbow has a hinged water cooled door on an outer wall.
30. The apparatus of claim 2b wherein said tobacco has a moisture content at said outlet airlock in said tangential separator of from about 13% to 15% by weight.
31. The apparatus of claim 26 wherein the air temperature in said apparatus is maintained at from about 320 (160EC) to about 420 (215.6EC) degrees F.
32. The apparatus of claim 26 wherein said tobacco has a moisture content at said inlet airlock of from about 21% to 23% by weight.
33. The apparatus of claim 26 wherein the airflow within said apparatus has an average velocity of about 6300 ft(1920m)/min at said inlet airlock.
34. The apparatus of claim 26 wherein said air intake duct has a downward preselected angle of curvature.
35. The apparatus of claim 28 wherein said water cooled door on said first elbow has a plurality of water channels formed therein.
36. The apparatus of claim 29 wherein said water cooled door on said second elbow has a plurality of water channels formed therein.
37. The apparatus of claim 26 wherein said vertically extending drying chamber is about 60 feet (18.29m) in length.
38. The apparatus of claim 26 wherein said tangential separator is further provided with a hinged water cooled door.
39. The apparatus of claim 26 comprising an interior duct wherein the interior duct comprises rounded comers.
40. The apparatus of claim 26 wherein said air intake duct has a cross sectional width of about 66 inches(167cm) and a height of about 18 inches (45.7cm).
41. The apparatus of claim 26 wherein said first elbow has a vertical expansion of about 32 inches (81cm) to about 27 inches (68.58cm) at said inlet airlock.
42. The apparatus of claim 26 wherein said apparatus has a zero pressure point within said inlet airlock and within said tangential separator.
43. The apparatus of claim 27 wherein said at least one air exhaust of said tangential separator is further comprised of a first and a second centrally aligned perpendicular air exhaust on opposed sides, said first air exhaust being in flow communication with a first high efficiency cyclone and said second air exhaust in flow communication with a second high efficiency cyclone.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1998/000472 WO1999034696A1 (en) | 1996-05-17 | 1998-01-09 | Tobacco drying apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2317561A1 CA2317561A1 (en) | 1999-07-15 |
| CA2317561C true CA2317561C (en) | 2006-08-15 |
Family
ID=22266183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002317561A Expired - Fee Related CA2317561C (en) | 1998-01-09 | 1998-01-09 | Tobacco drying apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP3441436B2 (en) |
| AT (1) | ATE246457T1 (en) |
| AU (1) | AU732659B2 (en) |
| CA (1) | CA2317561C (en) |
| DE (1) | DE69817024T2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3922985B2 (en) * | 2002-08-22 | 2007-05-30 | 日本たばこ産業株式会社 | Drying method of air-dried seed tobacco |
| PL2929788T3 (en) * | 2014-04-04 | 2018-10-31 | Garbuio S.P.A. | Drying plant for particulate materials |
| CN110584181B (en) * | 2018-06-13 | 2020-12-29 | 红塔烟草(集团)有限责任公司 | High-precision stem shred separating equipment and method thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1231384A (en) * | 1958-07-24 | 1960-09-28 | British American Tobacco Co | Method and apparatus for heating and cooling tobacco or for subjecting it to only one of these two treatments |
| JP3140039B2 (en) * | 1990-11-07 | 2001-03-05 | 日本たばこ産業株式会社 | Flash drying method and apparatus for tobacco raw materials |
| US5582193A (en) * | 1994-08-24 | 1996-12-10 | Philip Morris Incorporated | Method and apparatus for expanding tobacco |
-
1998
- 1998-01-09 JP JP2000527164A patent/JP3441436B2/en not_active Expired - Fee Related
- 1998-01-09 CA CA002317561A patent/CA2317561C/en not_active Expired - Fee Related
- 1998-01-09 AU AU58206/98A patent/AU732659B2/en not_active Ceased
- 1998-01-09 AT AT98901764T patent/ATE246457T1/en not_active IP Right Cessation
- 1998-01-09 DE DE69817024T patent/DE69817024T2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2317561A1 (en) | 1999-07-15 |
| AU5820698A (en) | 1999-07-26 |
| JP2002500031A (en) | 2002-01-08 |
| ATE246457T1 (en) | 2003-08-15 |
| DE69817024T2 (en) | 2004-02-05 |
| AU732659B2 (en) | 2001-04-26 |
| JP3441436B2 (en) | 2003-09-02 |
| DE69817024D1 (en) | 2003-09-11 |
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