Tobacco bale steam injection

A method and apparatus for steam injection of tobacco bales for use in the opening process. In the apparatus, at least one orificed steam injection plate is brought in flush contact with a tobacco bale that is stationary or in motion and steam is caused to emit from the orifice and is thereby injected into the bale moistening, conditioning and loosening the bonds between the tobacco leaves. In the method, as the tobacco bale is conveyed past the steam injection orifice plate, the plate is moved in flush contact therewith, steam is supplied to the plate and emits therefrom through the orifices to penetrate the tobacco bale. The bale so conditioned is subsequently broken up by a rotating cylinder.

BACKGROUND 
The present invention relates to the treatment of tobacco bales and more 
particularly to a method and apparatus for injecting steam into a bale of 
tobacco to moisten the tobacco and to loosen the bonds between the leaves 
of the bale prior to breaking the bale apart. 
Tobacco bales are generally a plurality of tobacco leaves arranged in a 
rectangular parallelepiped in layered relationship with their leaf planes 
being generally mutually parallel and being generally parallel to two 
opposing surfaces of the bale. The other four surfaces of the bale are 
referred to as "grained" and are generally perpendicular to the leaf 
plane. The bales are held together by burlap wrapping, string or other 
suitable means. During forming, processing, storage and transportation of 
the bale, the tobacco leaves in the bale typically become stuck together 
and dried to some extent depending upon the environmental conditions the 
bale is subjected to, the characteristics of the tobacco leaves and 
pressure on the leaves exerted by the bale wrapping. When the tobacco is 
to be removed from the bale wrapping and used, it is necessary to remove 
the wrapping and separate the bale into predominantly individual leaves as 
gently as possible to minimize leaf breakage. This process is called 
"opening" of the bale. The breaking of the bonds between the stuck 
together leaves may be accomplished by moistening and heating the leaves 
by subjecting the bale to steaming in a vacuum chamber as in U.S. Pat. No. 
3,898,996 or by steam injection into the bales as in U.S. Pat. No. 
4,287,897. The steam injection device of the '897 patent includes a pair 
of vertical pipes between which the bale is passed by means of a conveyor 
belt. Steam supplied to the pipes is injected into the bale by means of a 
plurality of holes provided therefor in the pipes. This device suffers 
from a number of disadvantages including the deflection of steam by the 
bale and thus escape of the deflected steam without efficient penetration 
of the bale. Moreover, injection is effected over only a limited contact 
area. 
SUMMARY OF THE INVENTION 
The present invention alleviates to a great extent the shortcomings of the 
prior art steam injection method and device, by passing the bale between 
orifice plates in flush contact with the bale grained sides and causing 
steam to emit from the orifices of the plate and penetrate the bale. The 
presence of the plates decrease to a great extent the amount of steam 
which is deflected by the bale surface and which therefore does not 
penetrate the bale. Thus, the steam may be injected at a lower more 
moderate pressure and at a lower rate of steam flow. 
It is the object of the present invention to provide a method and apparatus 
for opening a bale of tobacco by efficient steam injection at moderate 
pressures and temperatures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Refer now to FIG. 1 there being shown a perspective view of tobacco bale 
steam injection apparatus in accordance with the present invention. 
Tobacco bale 10 is conveyed by conveyor 14 past the steam injection plates 
24, 26, 28 and 30. Legs 19 support idle roller 16 and conveyor drive 
roller 18 upon which conveyor 14 is wrapped. Motor 22 turns wheel 23 which 
drives roller 18 by means of belt 21 and pulley 20. 
Tobacco bale 10 is aligned with the grained sides 17 and 86 and the 
opposing sides (not shown) generally parallel with the direction of travel 
and nongrained side 85 and its opposing side (not shown) aligned generally 
normal to the direction of travel. It is preferable to position the bale 
with the narrowest dimension between the plates if only one or two steam 
injection plates are being used. 
Steam injection plate 26 is oriented parallel to the lines of travel of 
conveyor belt 14 as represented by arrow 25 and is mounted to be movable 
in a direction traverse to arrow 25. 
As illustrated in FIG. 1, plate 26 is movable by a pneumatic arrangement 
including piston 42 ridgedly attached at one end to plate 26 and extending 
at the opposing end into cylinder 44 which is connected to a fluid 
pressure control 46 via conduit 45. Suitable structural mounting (not 
shown) supports cylinder 44. 
Steam is supplied to injection plate 26 through inlets 40 via conduit 39, 
flexible conduit 38 and conduit 35 from steam source 34. 
Plate 28 is fixably mounted to oppose plate 26 and is provided with 
corresponding steam supply means (not shown). Plate 24 is mounted above 
and generally parallel to the plane of conveyor belt 14 and is provided 
with appropriate steam supply means and moving means to effect desired 
upward and downward movement of plate 24. Plate 30 is mounted below belt 
14 and is provided with corresponding steam supply means (not shown). Each 
of plates 24, 26, 28 and 30 are of hollow construction with a plurality of 
steam injection orifices for supplying steam to bale 10 being passed 
thereby by conveyor 14. Alternatively, each plate could be mounted to be 
movable to some extent if desired. 
In operation, bale 10 is positioned on conveyor 14 with the opposing 
nongrained sides 85 positioned generally normal to the direction of travel 
25 such that the four grained sides are exposed to steam jets from the 
orificed surfaces of plates 24, 26, 28 and 30. In this regard, it is noted 
that conveyor belt 14 is porous to allow the issuance therethrough of 
steam from plate 30 to bale 10. As bale 10 travels between plates 24, 26, 
28 and 30, movable plates 24 and 26 are urged against the surface of bale 
10, moving it if necessary in contact with plates 28 and 30, thus 
inhibiting the escape of steam between the plates and the bale surface as 
the bale travels thereby. Plate 24 is conservatively sized in anticipation 
of the smallest probable bale traverse dimension to preclude interference 
with the movement of plate 26. 
Refer now to FIG. 2, there being shown an alternate embodiment of the 
invention. Plates 48 and 50 are similar in construction to plates 28 and 
26 respectively of FIG. 1 with associated steam supply means and moving 
means (not shown). FIG. 2 illustrates that a progression of plates may be 
used to effect a selective series of varied steam treatments. Moreover, 
end plates 52 and 54 are provided to inject steam into the leading and 
trailing ends of bale 10 (not shown) now oriented with the plane of the 
grains vertical. Piston 56 is attached to plate 52 and cooperates with 
cylinder 58 attached to plate 54 and pneumatic fluid pressure control 57 
and conduit 59 to urge plates 52 and 54 together against the leading and 
trailing ends of bale 10. 
Plates 52 and 54 ride along with bale 10 by plates 48 and 50 and are 
thereafter lifted via pneumatic piston 60 and cylinder 62 and pneumatic 
fluid pressure control 64 and conduit 63 arrangement suspended in track 68 
by flange 66 and moved back by claim 70 connected to cylinder 62 by 
fastener 67. Chain 70 is driven by motor 77 turning wheel 75 and belt 76 
turning pulley sprocket 74. 
Refer now to FIG. 3 there being shown a sectional view of plate 26 taken 
along line III--III of FIG. 1. Steam enters cavity 82 through the back 
wall 84 of plate 26 via inlet 40, and escapes through front wall 83 via 
orifices 80 to be injected into a grained surface of bale 10. Orifices 80 
may be any appropriate size with a preferred range of between about one 
and about three thirty-seconds of an inch. As the orifice decreases in 
size, the velocity of steam emitted therefrom increases and steam mass 
flow there through decreases. The increased steam velocity generally gives 
greater penetration into the bale. 
Referring back to FIG. 1, note that four inlets 40 (three in view) are 
provided to plate 26. This arrangement overcomes to some extent a pressure 
distribution problem experienced when only a single inlet to a plate is 
used. In such a single inlet configuration, steam pressure within the 
plate decreases as distance from inlet 40 increases because steam mass is 
progressively lost through the orifices 80. By providing a plurality of 
inlets 40, the steam pressure distribution within plate 26 is flattened 
and more uniform steam injection into bale 10 is effected. 
A steam pressure of between about forty and about sixty-five pounds per 
square inch gauge a steam temperature of at least about two hundred 
degrees Fahrenheit and a steam mass flow rate of between about twelve 
hundred and about seventeen hundred pounds mass per hour with a bale 
residence time of between about one to three minutes is preferable for a 
turkish bale wrapped in burlap with dimensions of about twenty-six by 
twenty-eight by fifteen inches with steam being injected in the two 
opposing largest sides which are grained sides. 
Refer now to FIG. 4 wherein an alternate steam plate arrangement 99 is 
shown. Arrangement 99 includes a plurality of pipes 91 having orifices 90 
and being interconnected by connecting plates 92, 93 and 94 by welds 95. 
Pipes 91 may be mutually aligned and interconnected in any desired 
configuration with correspondingly shaped connected plates such as 92 
welded between to prevent the escape of deflected steam thus enabling more 
efficient steaming of the tobacco bale. 
EXAMPLE 1 
A bale of turkish tobacco wrapped in burlap with dimensions of 
approximately fifteen by twenty-six by twenty-eight inches and having the 
leaf plane generally parallel to the smallest two opposing sides, the 
other sides being grained, was conveyed between two generally flat 
rectangular steam injection orifice plates twelve inches by twenty-four 
inches and oriented generally parallel to two of the opposing grained bale 
sides and positioned for flush content therewith. Each plate had one 
hundred seventy-five one sixteenth of one inch diameter orifices evenly 
distributed over the surface of the plate in a triangular lattice pattern. 
As the bale progressed between the plates, one plate was moved in to 
effect flush contact of both plates with the bale and three hundred and 
forty-five degrees Fahrenheit steam supplied at a rate of seven hundred 
and five pounds mass per hour to each plate at a pressure of fifty pounds 
per square inch gauge. After six minutes, the bale had completely passed 
through the plates each point on the surfaces being subjected to steam 
injections for a residence time of two minutes. Steam penetration was 
complete to the center of the bale. 
EXAMPLE 2 
For the same conditions as Example 1, a similar bale was positioned between 
the plates, the plates were moved into flush contact, the stationary bale 
was steamed for two minutes. Steam penetration was complete to the center 
of the bale. 
The above description and drawings are only illustrative of preferred 
embodiments which achieve the objects, features and advantages of the 
present invention and is not intended that the present invention be 
limited thereto. Any modification of the present invention which comes 
within the spirit and scope of the following claims are considered part of 
the present invention.