US2752695A - Apparatus for treating tobacco prior to redrying - Google Patents

Description

J ly 3, 1956 P. F. JACKSON 2,752,695

APPARATUS FOR TREATING TOBACCO PRIOR TO REDRYING Original Filed April 2, 1951 6 Sheets-Sheet 1 FIG. lb ['4 Inventor Peter F. Jackson,

23 f 23 By wwwfw Attorneys.

July 3, 1956 P. F. JACKSON 2,752,695

APPARATUS FOR TREATING TOBACCO PRIOR TO REDRYING Original Filed April 2, 1951 6 Sheets-Sheet 2 FIG. 3

Peter E Jackson,

July 3, 1956 P. F. JACKSON 2,752,695

APPARATUS FOR TREATING TOBACCO PRIOR TO REDRYING Original Filed April 2. 1951 6 Sheets-Sheet 3 1 4; 54 II Coin: II 48 I fign J o I 49 29 I H 'l A E 43 Lil 4l :1 55 \i 2o 39 [1 .1:|g

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37 i 27 l7 27 1 Ln 3 '9 I I8 30 33 33 32 32 4 Inventor Peter F. Jackson,

July 3, 1956 P. F. JACKSON APPARATUS FOR TREATING TOBACCO PRIOR TO REDRYIN 6 Sheets-Sheet 4 Original Filed April 2, 1951 Inventor Peter F. Jackson y 2 a torr iys,

July 3. 1956 P. F. JACKSON 2,752,695

APPARATUS FOR TREATING TOBACCO PRIOR TO REDRYING 6 Sheets-Sheet 5 Original Filed April 2, 1951 In venfor Peter E Jackson, By m eys.

y 3, 1956 P. F. JACKSON 2,752,695

APPARATUS FOR TREATING TOBACCO PRIOR TO REDRYING Original Filed April 2. 1951 6 Sheets-Sheet 6 Inventor Peter F. Jackson, y x412 fifi 04M torney s APPARATUS FUR TREATING TOBACCO PRIOR TO REDRYING Peter F. Jackson, Henderson, N. C.

Original application April 2, 1951, Serial No. 218,79}. Divided and this application February 29, 1952, Serial No. 274,213

2 Claims. (Cl. 34-85) This invention relates to the treatment of tobacco, and particularly to apparatus for simultaneously partially drying hands of tobacco and causing the hands to open, preparatory to the conventional operation commonly referred to as re-drying.

In the usual commercial practice, tobacco is delivered by the grower to a warehouse, where the tobacco is sold at auction. As it appears on the warehouse floor, the tobacco, usually contained in baskets or the like, is in the form of hands, and is usually quite dry and brittle, the moisture content being in the neighborhood of 18-20%. It the tobacco has not been heat cured in the barn, but rather allowed to cure slowly without application of artificial heat, as is the case for example in the tobacco growing areas of Maryland, the tobacco from the warehouse fioor is packed substantially without further treatment. On the other hand, if the tobacco has been heat cured, as in a barn by the action of artificial heat from a flue system or oil burners, according to the practice in the Carolinas, the stems or butts of the hands are moist, though the leaves themselves are relatively dry, and it is necessary to take the tobacco from the warehouse floor and subject it to re-drying and ordering before packing.

According to the common commercial practice of redrying, the hands of tobacco are usually mechanically or manually shaken in order to at least partly open the leaves of the hands. The hands are then placed on sticks and passed through a drying kiln in which the moisture content of the tobacco is reduced to about 9%. The tobacco is then ordered, as by treatment with live steam, to bring the moisture content up to about 11%, uniformly throughout the hands, and the ordered tobacco can then be packed in hogsheads or the like without breakage of the leaves. As taken from the warehouse, the hands of tobacco are tight, that is, the leaves of the hand are bunched closely together. In this compact relation resulting from being compressed together while initially green, the leaves have become somewhat dry and their irregularities cause adjacent leaves to resist separation. My treatment causes the leaves to soften and become smoother, whereby the leaves are separable and the entire hand more open. If the leaves of the hands are not loosened, as by the conventional manual or mechanical shaking operation, the re-drying and ordering steps are materially inpeded. However, the mechanical shaking operation has two major disadvantages. First, either too much manual labor is required, or complex mechanical shaking conveyors must be employed. of the hands, which usually must be My invention ing hands mechanical shaking step is entirely eliminated, so that a a very material loss of higher grade tobacco is prevented. Further, my inspaced parallel endless 2,752,695 Patented July 3, 1956 heated air in accordance with my invention results in av softening and smoothing of the tobacco leaves, the leaves thus becoming less brittle. This changed quality of the leaves, resulting from treatment with dry heated air, is not the result which would be expected. The expected result would be increased stilfness, without any opening or loosening of the leaves in the hand. But, to the con trary, the leaves are rendered pliant and flaccid and free from any tendency to cling together, so that they are in the best possible loosened condition when subjected to the usual treatment in the redrier. Whereas the leaves in the tobacco hands as ordinarily received at the re-drying plant are more or less closely bunched and crimped together and are relatively stiff and brittle, the apparatus of the present invention makes possible the use of a method which not only softens the leaves and makes them freely separable from each other without damage to the leaves, but also extends such conditioning the entire length of the leaves in the hand.

In order that the invention may be understood in detail, reference. is had to the accompanying drawings which form a part of this specification and wherein:

Figs. 1, 1A and 1B are diagrams illustrating successive steps of my tobacco treating method practiced in the apparatus of this invention;

Fig. 2 is a perspective view which a stick of tobacco hands showing the manner in is carried by a pair of conveyor chains in accordance with the invention;

Fig. 3 is a front elevational view of a tobacco treating apparatus constructed in accordance with the invention;

Fig. 4 is a top view of the apparatus shown in Fig. 3, a portion of the casing being broken away; A

Fig. 5 is a side elevational view of the apparatus illustrated in Fig. 3, a portion of the casing being broken away;

Fig. 6 is a diagrammatic side elevation of certain of the parts of the apparatus shown in Fig. 3, illustrating the manner in which heated air flows within the apparatus;

Fig. 7 is a detail sectional view taken on the line 7-7, Fig. 3, parts being shown in elevation;

Fig. 8 is a detail sectional View taken on the line 8-8, Fig. 3, parts being shown in elevation;

Fig. 9 is a detail elevational view illustrating one form of conveyor chain which may be employed in the apparatus; and

Fig. 10 is a diagrammatic view showing the relation between the apparatus of my invention and a conventional tobacco drying kiln with which the apparatus is used.

I have found that a hand of tobacco may be loosened, with the leaves limp stem to tip, solely by the action of heated dry air. According to my invention, the hand is suspended with theleaf tips pointing downwardly and the stem upwardly, and the hand thus the stem to the leaf tips. Preferably, the hand is moved along transversely to its length, first through the upward ly directed current of air and then through the downwaidly directed current of air. The leaves of the hand before treatment are relatively stifr and closely bunched; after the treatment just described the leaves hang freely in a loose, pliant condition, so that conditioning action injthe' re-drying step may afiect the enthe surface ofea'ch leaf throughout the hand to an extent which would not havebeen possible if the leaves were stiff and crimped together.

'The precise conditions of the operation for any one batch of tobacco will depend upon the condition of the tobacco. As a general rule, the temperature of the air should be within 'therange of l60-200 F. The air shouldbe dry in the sense that it is unsaturated and will therefore take up moisture, and in this respect the present invention must" be contrasted to prior proposals for pre-t're'ating' tobaccowith steam or moist air. Preferabl in'my process, the heated air should be below 30% relative" humidity.

Ordinarily, I prefer to support the hands on the usual tobacco sticks and carry thesticks through the currents of heated dry air" by means of a conveyor. Thus, the speed'ofthe'conveyor may be selected to maintain the hands within the area of the heated dry area'tor the proper time. In a preferred practice of the invention,

the two'currents ofheated dry air are irnmediatelyad-' jacent, providing an area of heated air extending for about eight feet in the direction of travel of the tobacco, andthe rate of travel of the tobacco is made to be about 15 feet per minute. Thus, each hand of tobacco remains inconta'ct with the heated dry air for about 30 seconds.

When a hand of tobacco is treated in this manner, I find that the hands are loosened and the leaves softened become smoother and are somewhat separated, and that the resulting condition is superior to that which can be obtained by manual shaking. After thehand has been subjected to the currents of heated dry air as just described, the hand can be carried directly into the re-dryer. Further, the preliminary treatment with heated dry air reduces the moisture content of the tobacco, although at the same time the leaves are rendered less fragile, so that the time required for the re-drying operation is materially'reduced. The time in the redryer is less because the opened condition of the treated hands renders the redryer action more efiective. All manual operations ordinarily required for opening the hand are eliminated by my apparatus and, since the speed of the conveyor in the drying-kiln can be increased, both because of the preliminary drying effect of my apparatus and because the tobacco hands are opened into a better condition for drying tharr'can be done by mechanical shaking, the number of man-hours required for the total re-drying operation is considerably reduced. In actual practice with one particular drying plant handling tobacco cured in the Henderson area of North Carolina, I have found that this method has reduced the number of man-hours required during one year'of operation from 70,000 to 56,000, while the amount of tobacco handled was increased 15% and the quality of the treated tobacco was improved.

The' manner in which I may practice my tobacco treating method is illustrated more precisely in Figs. 1, 1A and 1B. The hand of tobacco is placed upon a tobacco stick 11 in'the conventional manner, with the leaf tips 10' thereof extending downwardly and the stem it) extending upwardly. As shown in Fig. 1, the hand, when first placed upon the stick 11, is bunched tightly together. With the hand 10 suspended as just explained, a current of heated dry air is directed upwardly about the hand, as illustrated in Fig. 1A. This may be accomplished by moving the hand 10 over an impeller 12, the impeller being arranged to direct air upwardly first across a heating element 13 of any conventional type and then upwardly intothe lower end of and about the hand of tobacco. After being subjected to the upward current of dry heated air, the tobacco is then subjected to a similar downward current, asshown in Fig. 1B. This may beaccomplished -As seen in Fig. 9, each link 21 paratus' embodying my by moving the tobacco below an impeller 14, which forces the air downwardly first across a suitable heating element 15 and then downwardly lengthwise of the hand 10 from the stem 10" to the tip 10'.

Of course, in commercial practice, a plurality of the hands 10 are supported upon each stick 11, and the sticks are supported by spaced parallel conveyors. For example, the sticks -may be carried by spaced endless conveyor chains 16 and 17, extending over sprocket wheels 18 and 19, as seen in Fig. 2. A commercial apparatus to carry out the method of my invention wil1= ordinarily be associated directly with a horizontal redrying kiln, and it is preferable that, as seen in Fig. 10, the endless conveyor extend continuously through the conventional re-drying kiln K and a pro-treating chamber P constructed in accordance with my invention. The construction of horizontal kilns for re-drying tobacco is well known, usually involving a pair of parallel spaced endless conveyor chains'16 and17for carrying the tobacco sticks, and an endless conveyor belt 20" of relatively fine wire mesh or' the like located in the kiln below the run of the tobacco to collect any fragments falling from the hands. of the conveyor chains may include a hook 22 to engage the tobacco stick at the end thereof, anda guide roller 23 is provided at the pivotpoint'betwe'en each link.

Referring now to Figs. 3-5, a"preferred forrn of apinvention" will be described. As best seen in Figs. '4 and 5, the forward end of the'converitional re-drying kiln K is joinedat 24 to a generally rectangular casing or enclosure "25, the spaced parallel endlessconveyor'chains 16 and 17 of the kiln being extended entirely through the casing'25 and running over the "sprocket wheels 18 and -19. The sprocket wheels 18 and 19 are carried by freely rotatable shafts 30 and 31, respectively, journalled in bearing plates 32 and 33, respectively, these bearing plates being mounted on hearing stands 34 and 35' secured to the frontsurfaces of the forward vertical frame members 27. Horizontal top frame members '26 are supported at their forward ends by'the vertical members 27, and-extend rearwardly to the kiln K. Similar horizontal bottom frame members 26, which may rest directly upon the floor of the drying room, extend beneath the top frame'rnembers 26, and the top and bottom-frame members are interconnected to verticalbraces 27. To the rear of the front frame members 27,sheet metal sides 28 are secured to the braces 27, and a sheet metal top closure 29 extends between the two central top frame members 26,- as seen in Fig. 4. A partial front closure 36 to confine theheated air, extending from the top of the chamber 25 to a'point somewhat above the top runs of the conveyor chains 18 and 19, as seen in Fig. 3, is secured to the forward surfaces of the braces 27', and hinged to this front closure is a drop closure 37 to helpconfine the heated air and which maybe lowered between the conveyor chains, or secured to raised positio'mas shown, by a hook and eye 38.

Thus, the chamber 25 comprises an enclosure joined at the back to the re-d'rying kiln K and open at the front for the admissionof-sticks of tobacco supported on the two endless conveyor chains.

Positioned just-within the enclosure 25 at the forward end thereof is a vertical hot air blower unit 39 supported on the floor by legs 40. This blower may be of any conventional typecapable'ofheating air and directing the same upwardly between the'conveyors 16 and 17. Preferably, I employ a hot-air blowerofthe type shown and described inUnited States Patent 2,300,574 to lepertinger, and comprising a steam coil provided with heat exchange fins, a-fan or impeller driven by an electric motor for passing air over the steam coil, and louvers for directing the discharge of heated air. Steam is supplied to the heat exchanger 39' of the blower unit '39 bya pipe 41, and-the condensate is discharge through a'pipe 42 provided with asteam trap 43. As seen in Fig.7, when the blower 39 is in place in the casing 25, there is provided an upright sheet metal closure 44 in front of the blower unit, and a screen 45 overlies the blower to prevent fragments of tobacco, etc., from falling upon the heat as seen in Fig. unit 39, that is,

supply line 50 controlled by a weight operated valve 51.

Both of the blower units take relatively cool air from the drying room in which the kiln is located, the lower blower unit 39 drawing air upward from the floor and the F. If the steam temperature in the two blowers is maintained such as to raise the temperature of the air to 160200 F., then the relative humidity of the air discharged from the blowers will be about 1823 and I have found these conditions to be ideal.

Below and slightly to the rear of the upper blower unit 46, beneath the conveyors 16 and 17, an exhaust opening 52, Fig. 5, is provided in one side of the casing 25. This opening communicates with the interior of a stack 53 and thence with a flue 54 extending through the roof of the building in which the kiln is located. The

directed upwardly the heat exchanger 39 thereof, and flowing upwardly past the tobacco sticks 11 (carried by the conveyors 16 and Simultaneously, air is directed downwardly by the blower unit 46, being heated by the heat exchanger 47 and travelling down past the tobacco sticks 11 toward the exhaust opening 52. Were it not for the downward current air from the upper blower unit 46, the upward current of air from the blower 39 would merely travel under surface of the top 29. But, because of the upper blower, this upwardly travelling current of air is drawn rearwardly and then downwardly, into the stream from the upper blower 46, and thence carried to the exhaust opening 52, into the stack 53 and out through the flue 54. Thus, substantially all of the heated air which has contacted the tobacco is exhausted from the casing 25.

In order to determine the temperature within the casing 25, I provide a thermometer 55, Figs. 4 and 6, having its temperature sensitive portion located within the casing and its indicating scale arranged on the outside of the sidewall 28. The fan motors and the conveyor motors are electrically powered, and the controls are preferably grouped in a single control panel 56, Fig. 5, so that the speed of the motors can readily be changed should the conditions of operation vary.

In operation, the hands of tobacco are placed upon the sticks without any preliminary treatment and the sticks are then loaded onto the conveyor chains 16 and 17 in the manner shown in Fig. 2. This operation is continuous, the conveyor chains operating to carry the tobacco through the chamber 25 and thence into the redrying kiln K. Within the chamber 25, the tobacco dry heated air flowing upwardly from the blower 39, and then by the dry heated air flowing downwardly from the blower 46. When the hands are carried into the kiln K, they will be in fully loosened condition, ready for drying operation. Also, their moisture content will have been considerably reduced by the action of the dry heated air, so that the speed with which they are moved through the kiln can be relatively high, as compared with the speed possible if the invention were not employed.

This application is a division of my application Serial No. 218,799, filed April 2, 1951, Method and Apparatus for Treating Tobacco Prior to Redrying, now Patent No. 2,714,385.

I claim:

1. In an apparatus for redrying hands of heat-cured tobacco without requiring mechanical shaking of the hands, the combination of a redrying kiln having an entrance end, a horizontal conveyor extending therethrough having means to transport tobacco sticks in a substantially horizontal position whereby the hands of tobacco carried by the sticks may depend with leaf tips downwardly directed, a casing joined to the entrance end of said kiln, said conveyor extending through both said kiln and said casing, said casing having top, bottom, and side walls joined to form a substantially enlcosed space but in cluding an entrance opening in the side of the casing opposite the entrance end of the kiln, said entrance opening extending above and below said conveyor, so that tobacco sticks may be placed on said conveyor and air may pass through said entrance opening into the casing, a first combination air heater and blower disposed within said casing adjacent said entrance opening and below said conveyor, said blower including an impeller for directing air from outside the casing through the entrance openjacent said kiln for exhausting air from said lower portion of the space outside the casing.

References Cited in the file of this patent UNITED STATES PATENTS

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