Abstract:
A method for harvesting bast plants that have stalks, husks, and seeds. The method includes cutting the bast stalks from the bast plants and promptly receiving the bast stalks onto a first belt without retting the bast stalks. The method then orients at least a portion of the bast stalks on the first belt, the longitudinal axis of the at least a portion of the bast stalks being generally oriented in the direction the first belt is moving. The husks and seeds may be removed from the bast stalks. The bast stalk may be packaged.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/074,778, filed Mar. 29, 2011, now U.S. Pat. No. 8,635,844, which is incorporated by reference herein in its entirety. This application is also related to U.S. application Ser. No. 13/074,665, filed Mar. 29, 2011, now U.S. Pat. No. 8,475,628. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an apparatus and process for harvesting bast plants, and particularly to orienting bast stalks while harvesting bast plants. 
     BACKGROUND OF THE INVENTION 
     Bast plants have a remarkable variety of uses. Bast fibers extracted from these plants are used in textiles, apparel, ropes and cordage, paper and composite fabrication, among other applications. The bast fibers can provide unique properties in textile structures while providing alternative, renewable, fiber supplies for cotton based and/or petroleum based fiber materials. Bast seeds yield oils for several end-uses, e.g., food grade oils, personal care products, paint additives, etc. Bast plants are compelling crops to harvest due to the broad uses, the wide geographic footprint most bast plants have for growing, and the typical yields. 
     Despite the variety of uses that bast plants generally have, bast plants have been developed toward either seed production or fiber production, but not necessarily seed and fiber production. More specifically, bast plants that primarily yield seeds for oil production and planting do not typically produce fibers suitable for textile production. Bast plants for seed production may have short fiber lengths and lower fiber yields. For example, flax plants ( Linum usitatissimum  L.) for fibers are taller, yield more fiber, have lower oilseed content and produce less seeds compared to flax plants grown for seed production. In addition, bast seed plant production substantially outpaces the production of bast fiber plants, thus bast fibers more suitable for textile applications have a limited supply. 
     Extracting fibers and seeds from bast plants and conditioning them into a state suitable for later use, e.g., fiber for yarn and fabric formation, is a complex and expensive process. Typically, bast plants are cut in the field and the stalks are allowed to rett for some period of time, e.g., a week to a month or more depending on climate. Retting begins the process of separating pertinacious materials from the fibers, and the fibers from the woody core of the plant. The retted stalks are then decorticated. There have, however, been advances in bast processing that minimize the need to field- or dew-rett bast stalks. Such advancements have given rise to new opportunities in harvesting bast plants in the field and present them for decortication. Decortication as used herein means removing the outer layers of the stalk and exposing the fibers. Following decortication, the fibers are intended for yarn formation, typically using long-line or wet-yarn spinning systems, as is known the art. 
     Harvesting through decortication, however, does not necessarily produce fibers suitable for modern high speed yarn spinning operations, e.g., cotton and/or cotton blend spinning systems. The amount of capital investment in process modifications required to process bast fibers on existing spinning systems exceeds the return running such fibers on those systems could provide. 
     There is a need, therefore, for an improved process for harvesting bast plants in the field, and packaging them in a form suitable for later processing. 
     SUMMARY OF THE INVENTION 
     A method and apparatus for harvesting bast plants having stalks, husks, and seeds that includes cutting the bast stalks from the bast plants and receiving the bast stalks onto a first belt. The method then orients at least a portion of the bast stalks on the first belt, the longitudinal axis of the at least a portion of the bast stalks being generally oriented in the direction the first belt is moving. The husks and seeds may be removed from the bast stalks. The bast stalks may be packaged. 
     These and other features, aspects, and advantages of the invention will be apparent from a reading of the following detailed description together with the accompanying drawings, which are briefly described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flow chart illustrating a process for harvesting bast stalks in a field according to an embodiment of the invention. 
         FIG. 2  is an illustration of an apparatus for harvesting bast stalks, with a portion of the apparatus cut-away, according to an embodiment of the invention. 
         FIG. 3  is a plan view of an apparatus for harvesting bast stalks using the apparatus shown in  FIG. 2 , with the housing and wheels removed. 
         FIG. 4  is an illustration of an orienting bar used in the apparatus shown in  FIG. 3 . 
         FIG. 5A  is a cut away plan view of a belt and chamber for orienting bast stalks shown in  FIG. 3 . 
         FIG. 5B  is a front elevation view of the belt and chamber shown in  FIG. 5A . 
         FIG. 6  is an illustration of a screen used in the process shown in  FIG. 3 . 
         FIG. 7  is an illustration of an alternate hopper design used in the process shown in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Certain exemplary embodiments of the present invention are described below and illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention, which, of course, is limited only by the claims below. Other embodiments of the invention, and certain modifications and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, modifications, and improvements are within the scope of the present invention. 
     According to common practice, the various features of the drawings discussed below are not necessarily drawn to scale. Dimensions of various features and elements in the drawings may be expanded or reduced to more clearly illustrate the embodiments of the invention. 
       FIG. 1  is a flow chart illustrating a process  100  for harvesting bast plants from a field, and orienting the stalks generally parallel to each other for later processing. Although bast plants typically are cut and laid on the field for retting, or transferred to a pond for pond retting, enzymatic treatments may eliminate altogether the need to field and pond rett the stalks. Such enzyme treatments are described in U.S. Patent Application Pub. No. 2010/0147472, the entirety of which is incorporated by reference into this description, International Publication No. WO 2007/140578, the entirety of which is incorporated by reference into this description, and U.S. Patent Application Pub. No. 2010/0285569, the entirety of which is incorporated by reference into this description. 
     Orienting bast stalks better prepares the bast stalks for decortication, and ultimately fiber preparation and yarn spinning. Having bast stalks aligned in a generally parallel orientation with respect to each other for decortication can improve fiber preparation and yarn spinning. For example, one purpose of fiber preparation, sliver formation, and the drafting processes in yarn spinning is to form fiber assemblies having fibers arranged substantially parallel, and with minimal mass variation along the length of the assembly. Highly aligned fiber assemblies with low mass variation have lower end breaks thereby increasing yarn efficiency, and yielding a stronger, smoother yarn. By aligning the bast stalks in parallel early in the fiber extraction process, the bast fibers obtained via decortication will be better suited to operate on existing cotton and cotton blend yarn spinning systems. 
     Bast plants harvested as described herein include, but are not limited to, flax, hemp, kenaf, and ramie plants. Further, bast plants intended for either seed or fiber production may be harvested as described herein. Bast plants include an outermost layer referred to as the epidermis, followed by the cortex and then the phloem or parenchyma. The phloem layer contains the longer cells that are the bast fibers. Adjacent the phloem layer is the cambium and pith. The pith is the thick woody core. As will be further detailed below, a combine and/or process for harvesting bast plants extracts the seeds, and initiates the process for extracting the bast fiber cells from the stalks. 
     As shown in  FIG. 1 , the process  100  begins by cutting bast stalks from the bast plants in a field with a cutting device further detailed below (block  110 ). The cut bast stalks may then undergo a first orienting step, which is intended to align a portion of the stalks generally parallel to each other (block  120 ). The portion of the outermost layers, leafy matter, and the seeds are removed from the stalks, also referred to as de-husking (block  130 ). The de-husked stalks may then undergo a second orienting step, intended to align a substantial majority of the stalks generally parallel to each other (block  140 ). The oriented stalks may be compacted (block  150 ) and then packaged (block  160 ), e.g., baled into round, square or rectangular bale. 
       FIG. 2  shows an apparatus (i.e. a harvester)  200  used to harvest bast plants from a field according to art embodiment of the invention. The apparatus  200  may be a vehicle, combine, or trailer having wheels that can be pulled behind a vehicle. While an embodiment of the invention is shown as the apparatus  200  for harvesting bast plants, harvesting as described herein may include a process of extracting stalks from plants. 
     As shown in  FIGS. 2 and 3 , the apparatus  200  is shown as a vehicle and may include a cutting device  210 , first transfer belt  220 , first orienting belt  230 , de-husking device  280 , second orienting belt  330 , and a baler  410 , each of which will be detailed below. As the vehicle  200  passes over the field  204 , the cutting device  210  may remove stalks  206  from upstanding bast plants  202  in the field  204 . Any conventional cutter for severing and collecting the bast stalks  206  for transfer through the vehicle  200  may be used. In the embodiment shown in  FIGS. 2 and 3 , the cutting device  210  includes a housing  212  having downwardly extending ramp  214  and walls  216  that guide the cut stalks  206  onto a transfer belt  220 . The transfer belt conveys the stalks to the first orienting belt  230 . 
     As shown in  FIGS. 2 and 3  the transfer belt  220  has a first end  222  positioned proximate the cutting blades (not shown) in the housing  212 , and a second end  224  proximate to the inlet end  231  of the first orienting belt  230 , which is above the front wheel  232  of the vehicle (shown in  FIG. 2 ). A plurality of slats  228  on the transfer belt  220  may grab and carry the stalks thereon toward the first belt  230 . One or more rollers  226  as shown in  FIG. 2  may drive the belt  228 . In alternate embodiments, however, any conveying mechanism may be used to transfer the cut bast stalks  206  from the cutter  210  to the first orienting belt  230 . 
     The transfer belt  220  and first belt  230  may be run with a speed differential that facilitates stalk separation during transfer. More specifically, the first belt  230  may be moving at a higher speed than the transfer belt  220 , or vice versa. The higher speed first belt  230  separates the bast stalks so that the lower density bast stalks are transported thereon compared to the higher density of bast stalks received on the transfer belt  220  initially. 
     Continuing with  FIGS. 2 , and  5 A, the first orienting belt  230  begins the process of aligning the stalks  206  parallel to each other. The first belt  230  has a longitudinal axis A that is parallel to the direction B the first belt  230  is moving. Positioned above the belt  230  is a chamber  240  having a plurality of bars  250 ,  260 , and  270  therein. The bars  250 ,  260 , and  270  are elevated above and arranged perpendicularly to the belt  230 . The bars  250 ,  260 , and  270  may oscillate back and forth across the belt  230  in the direction C, as indicated by the arrows. The first orienting belt  230  and chamber  240  are similar to second orienting belt  330  and chamber  340  described below. While the first belt  230  is shown in  FIGS. 2 and 3  as a single conveyor, the first belt  230  may comprise multiple belts arranged end-to-end, each progressing the bast stalks through the chamber  240  at a different or same speed. In such an embodiment, the speed of each belt may be adjusted to facilitate stalk transportation. For example, the first belt  230  may comprise a first portion and a second portion, wherein the second portion has a speed that is greater than the first portion. When the bast stalks pass from the first portion to the second portion, the bast stalks partially separate from one another. 
     As shown in  FIGS. 4 ,  5 A, and  5 B, each bar  250 ,  260 ,  270 , includes a horizontal support  251 ,  261 ,  271  and a plurality of tines  252 ,  262 ,  272  that extend downwardly and orthogonally from the support toward the belt  230 . Support  261 , tines  262 , and support  271  and tines  272  are not shown in the figures. Turning to  FIG. 4 , the tines  252  are spaced apart a distance D to allow bast stalks to pass therethrough. The tines  252  may be connected to the support  251 . The tines  252  may also be attached to the support  251  via mechanical fasteners to facilitate repair and replacement. 
       FIGS. 3 through 5A  show how the bars can oscillate across the belt  230 . In an embodiment, actuators  253 ,  263 ,  273  may cause the bars  250 ,  260 ,  270  to move back and forth across the first belt  230  as shown. Actuators may use hydraulic fluid pressure or pneumatic pressure to move the supports across the belt  230 . Each of the bars  250 ,  260 ,  270  may be independently movable. Further, the bars may oscillate with respect to each other in a coordinated manner to maximize orientation of the bast stalks. For example, the first bar  250  may oscillate at a first frequency and the second bar  260  at a second frequency that is lower than the first frequency. The third bar  270  may oscillate at a lower frequency than the first and second bars  250  and  260 , respectively. Frequency refers to the rate the bar completes one cycle back and forth across the belt. 
     Turning now to  FIGS. 2 and 3 , as the bast stalks  206  approach the first oscillating bar  250  within the chamber  240 , the tines  252  begin to separate and align the stalks within the spacings D. The partially oriented stalks are then presented to the second bar  260  oscillating across the axis A of the belt  230 . The tines  262  (not shown) further arrange the stalks within the spacings D to orient the stalks generally parallel to the axis A of the first belt  230 . The stalks are then presented to the final bar  270  and tines  272  (not shown), wherein movement of the tines  272  (not shown) and the belt  230  cause further orientation of the bast stalks  206 . Although three bars  250 ,  260  and  270  are shown, more or less may be used. 
     Returning to  FIGS. 2 and 3 , the bast stalks exit the chamber  240  and are presented to the de-husking device  280 . The de-husking device  280  removes seeds, leafy matter, if any, and portions of the epidermal and cortex layers from the stalks  206 . The de-husking device may begin mechanically breaking the wood core of the stalks, which can facilitate fiber extraction later. 
     In the embodiment shown in  FIGS. 2 and 3 , the de-husking device  280  includes a plurality of roller sets  282   a ,  282   b , and  282   c  that present de-husked stalks to a shaker screen  290 . A hopper  294  is positioned below the roller sets  282  and screen  290  to collect materials removed from the stalks. An alternate hopper configuration is shown in  FIG. 7 , and includes the hopper  594  has walls  595  an inclined bottom  596 . A drive auger  597  may be positioned proximate the hopper bottom  596  to remove seeds and debris through an opening (not shown). The hopper  594  may be emptied during stalk harvesting, for example, the vehicle  200  may stop and the hopper emptied as needed. 
     Each roller set  282  comprises a first roller  284  and a second roller  286  positioned above and proximate to the first roller  284 . The rollers  284  and  286  in each set may have a smooth surface as shown. The pressure applied to the stalks as they pass between the first  284  and second  286  rollers may break and release some of the outer layers of stalks, exposing the fiber layer underneath. In other embodiments, the rollers  284  and  286  may be knurled, serrated, have indentions, projections, ridges or other surface configurations to facilitate de-husking the bast stalks. Further, the surface details of the rollers  284  and  286  in each roller set  282  may differ. For example, the first roller  284   a  may have a smooth surface and the second roller  286   a  may have ridges. The stalks  206  exit the de-husking device  280  onto a screen  290 . 
     As shown in  FIGS. 2 ,  3  and  6 , the screen  290  is sized to span the space between roller set  282   c  and the second orienting belt  330 . The screen  290  has a plurality of openings  292  (shown in  FIG. 6 ) sized to permit the removed outer skins and seeds to pass therethrough. The screen may be agitated to facilitate passing the removed materials from the stalks  206  through the screen  290  as they are presented to the second orienting belt  330 . In an alternate embodiment, the screen  290  can be a belt capable of transporting stalks from the roller set  282   c  to the belt  330 , but having openings to allow outer skins and seeds and the like to pass therethrough to the collection hopper  294 . First and second screen rollers  291  and  292  positioned above the screen  290  convey the stalks toward the belt  330 . While two rollers are shown, three, four or more such rollers may be used. The collection of outer skins, seeds and leafy materials allows for the reclamation and later processing of the bast seeds. In alternate embodiments, the removed materials may be left on the field. 
     As shown in  FIGS. 2 ,  3  and  5 A, the second orienting belt  330  may further align the bast stalks  206  parallel to each other. The second belt  330  has a longitudinal axis A′ that is parallel to the direction the second belt  330  is moving, shown in  FIG. 3  by the arrow B. The first and second orienting belts  230  and  330  operate similarly. Rollers  336  may drive the second belt  330 . The second belt  330  includes a chamber  340  positioned above the belt  330 , and a plurality of bars  350 ,  360 , and  370  elevated above and arranged perpendicularly to belt  330 . Each of the bars  350 ,  360  and  370  are capable of oscillating back and forth across the belt  330  in the direction indicated by the arrows E. The bars  350 ,  360  and  370  have a similar design and components to the bars  250 ,  260  and  270  described above and shown in  FIGS. 4 and 5B . Further, the bars  350 ,  360  and  370  may oscillate with respect to each other in a coordinated manner to maximize orientation of the bast stalks on the second belt  330 . For example, the first bar  350  may oscillate at a first frequency and the second bar  360  at a second frequency that is lower than the first frequency. The third bar  370  may still oscillate at a lower frequency than the first  350  and second  360  bars. 
     Continuing with  FIGS. 2 and 3 , as the bast stalks  206  approach the first oscillating bar  350  within the chamber  340 , the tines  352  (not shown) begin to separate and align the stalks within the spacings D. The partially oriented stalks are then presented to the second bar  360  oscillating across the axis A′ of the belt  330 . The tines  362  (not shown) arrange the stalks within the spacings D to further orient the stalks generally parallel to the axis A′ of the second belt  330 . The stalks are then presented to the final bar  370  and tines  372  (not shown), wherein movement of the tines  372  (not shown) and the belt  340  cause further orientation of the bast stalks  206 . Although three bars  350 ,  360  and  370  are shown, more or less may be used. The bast stalks exit the chamber  340  substantially parallel to the longitudinal axis A′ of the second belt  330 . 
     As shown in  FIGS. 2 and 3 , the oriented bast stalks may be compacted via compaction rollers  380 . The rollers include a first roller  382  positioned above and in contact with the second roller  384  and forming a nip  385  therebetween. The nip  385  is positioned near and at about the same elevation as the exit end  332  of the second orienting belt  330 . The position of the nip  385  allows the rollers  380  to grab and compress the oriented bast stalks, and then present the compacted bast stalk assembly to the transfer belt  390 . In the embodiment shown in  FIGS. 2 and 3 , the first roller  382  may be compliant to compress the bast stalks against the second roller  384  surface. In other alternate embodiments, the first  382  and second  384  rollers may be compliant. 
     The second belt  390  transfers the compacted bast stalks to packaging. Continuing with  FIGS. 2 and 3 , the compacted bast stalks are shown packaged into a bale  402  using a round baler  410 . The baler  410  includes housing  412 , accumulating guide  413 , moveable door  414 , and a wrap device  416  positioned below the housing  412  and proximate the second transfer belt  390 . The stalks are presented to the baler  410  and accumulated using the guide  413  within the housing  414 . When a certain mass of stalks have been accumulated in the housing  412 , wrap  418  is unwound from the wrap device  416 , passes over guide rollers  419 , and surrounds the bale  402 . A sensor (not shown) may detect when wrapping is complete, initiate instructions to cut the wrap  418 , and activate the moveable door to release the bale  402  onto the field  204 . While a round baler is shown, the oriented bast stalks may be packaged any number of ways that maintain the parallel orientation of the stalks, e.g. a square, rectangular bale. 
     The harvester may package the bales with desired properties that facilitate later processing. The bale density (lb/ft 3 ) may be adjusted to better facilitate opening, separation and orientation of the bast stalks, depending on the conditions of the bale. For example, the moisture content of the bale may impact bale density; as the moisture content of the bale increases, the density of the bale should be decreased, which would impact later processing. A compact, dense bale may require more aggressive opening and separating to facilitate alignment later in the process compared to bales with a lower density. Conversely, bales with a lower density may need less aggressive opening and/or separation to facilitate bast stalk alignment later in the process. In alternative embodiments, when square or rectangular bales are used, a baler may compact and orient the stalk therein for later processing. For example, a bale compactor can have surface with a plurality of extending rods having a plunger at the distal end thereof. As the compactor compresses the bales, the rods and plungers begin to orient the stalks within the square/rectangular bale. In other embodiments, the oriented bast stalks may be arranged in a hopper (not shown). 
     Although the present invention has been described with exemplary embodiments, it is to be understood that modifications and variations may be utilized without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims and their equivalents.