WO1997045573A1

WO1997045573A1 - Harvesting and processing green fibrous plant stalks

Info

Publication number: WO1997045573A1
Application number: PCT/AU1997/000329
Authority: WO
Inventors: Charles George Mierisch
Original assignee: Australian Hemp Company Limited
Priority date: 1996-05-24
Filing date: 1997-05-23
Publication date: 1997-12-04
Also published as: AUPO010496A0

Abstract

Methods and apparatus for processing a green plant stalk having a fibrous outer part and an inner hurd are disclosed. The method includes the steps of facilitating rupture of bonds between the fibre and the hurd in a bond rupturing step, splitting the stalk substantially longitudinally to expose the hurd, and decorticating the split stalk (30a, 30b) to separate the fibre from the hurd. The apparatus includes bond rupture means to facilitate the rupture of bonds between the fibre and the hurd, counter-rotating pressing rollers (39, 40), splitting means (41) for splitting the stalk substantially longitudinally and decorticating means (50) for thesplit stalk to separate the fibre from the hurd. A plant stalk tobe processed according to processing methods and apparatus may be a hemp stalk. A particularly preferred hemp is that of the genus Cannabis sativa L and species thereof. Methods and apparatus for harvesting and processing a bast crop are also disclosed.

Description

HARVESTING AND PROCESSING GREEN FIBROUS PLANT STALKS

The present invention relates to improvements to crop harvesting, and more particularly but not exclusively to the processing of Cannabis saliva, better known as hemp.

BACKGROUND OF THE INVENTION

Hemp has a number of commercial uses due to the properties of its fibre, which include strength and resilience. Uses of the fibre include as a constituent in the production of paper, fibreboard and rope. Hemp fibre also has the capacity lo replace cotton as a component of textiles. With the likelihood of gradual relaxation of hitherto strict legislative control over the cultivation and processing of hemp, it is likely to become increasingly attractive to farmers as a valuable cash crop.

The stalk of a hemp plant is generally of circular cross-section, and comprises a fibrous outer and an inner core or hurd. The fibre of the plant is generally the more valuable commodity, although the hurd has some uses. It is therefore desirable to release the fibre from the hurd to yield a value-added commodity.

The principal difficulty in processing hemp has been found to lie in being able to readily separate the fibre from the hurd, otherwise known as decortication.

A number of proposals have been suggested for separating the fibre from the hurd. The principal category of separation is mechanical separation. Of the mechanical operations, scutching has traditionally been most widely used. Scutching involves manually beating the hemp stalk until the hurd is dislodged from the fibre. This is usually followed by a manual mechanical stripping operation using a bladed scutching wheel to strip the outer fibre away from the hurd. As this method is generally a manual operation, it can be very labour-intensive and time-consuming and hence inefficient. Scutching has therefore not been found to be suitable for large scale commercial processing of hemp.

Other mechanical methods include the use of ultrasonics, which employ sound waves to generate vibrations to break the bonds between fibre and hurd.

Processing of hemp in a similar manner to that of flax has also been proposed. This method involves retting of the hemp, drying and breaking until the fibre separates from the core. Again this method is time-consuming and not generally suited to large- scale commercial operation. Some mechanical harvesting of hemp is also known. None of the prior art methods proposed is however suited to broadacre production or has satisfactorily harvested and processed hemp efficiently on a commercial scale.

In particular the foregoing methods require that separation of the fibre from the hurd occurs only after the stalk has been dried and/or retted.

SUMMARY OF THE INVENTION

The present invention accordingly provides in one embodiment a method for processing a plant stalk having a fibrous outer part and an inner hurd, the processing being commenced when the stalk is green, the method including the steps of facilitating rupture of bonds between the fibre and the hurd in a bond rupturing step, splitting the stalk substantially longitudinally whereby to expose the hurd, and decorticating the split stalk whereby to separate the fibre from the hurd.

The present invention provides in another embodiment apparatus for processing a plant stalk having a fibrous outer part and an inner hurd, the processing of the stalk being commenced when the stalk is green, the apparatus including bond rupture means to facilitate the rupture of bonds between the fibre and the hurd, splitting means for splitting the stalk substantially longitudinally, and decorticating means for the split stalk whereby to separate the fibre of the stalk from the hurd.

A plant stalk to be processed according to processing methods and apparatus of the present invention may be a hemp stalk. A particularly preferred hemp is that of the genus Cannabis sativa L and species thereof. Other plant stalks are envisaged for processing in accordance with the present invention, including Kenaf, Ramie, sugar cane and other bast crops.

A method according to the present invention may include the step of observing the growth pattern of the hemp plant in the field, whereupon harvesting and decortication of the crop may be commenced at a predetermined phase of growth of the plant.

It has been observed that the bond between the fibre and hurd varies at various stages of growth of the plant. I have found that there is a period in the growth phase of the plant during which if harvesting and decortication is completed the ability to readily rupture the fibre/hurd bond can be enhanced. In a preferred embodiment, harvesting and decortication are commenced when the plant is green, also known as freshly cut or fresh green, and the fibre of the stalk remains sufficiently fine for textile use, that is to say, prior to pollen formation. In a particularly preferred embodiment, the stalks should be harvested and processed at the latest just prior to the commencement of seed development of the plant, and/or just as flowering of the plant is beginning. A preferred indicator has been found to be when about 50% of the crop is flowering It has been observed that leaving the crop in the field for longer than the preferred harvesting and processing time can change the characteristics of the resulting fibre, rendering it coarse and more difficult to work. This can limit the further uses to which the fibre can be put.

A bond rupturing step according to the present invention is preferably capable of facilitating the rupture of bonds between the fibre and the hurd of the stalk for a subsequent decortication operation. The arrangement may be such as to distort the stalk by applying constant or varying pressure to a surface of the stalk. This arrangement has been found to assist in loosening the adhesive bond between fibre and hurd whereby to enhance the effectiveness of a subsequent decortication operation.

A processing method according to the present invention may include a shape modification step for the stalk. The shape modification step is preferably such that the generally circular cross-section stalk is substantially flattened during the shape modification step. Modification of the shape of the stalk has been found to assist in enhancing the effectiveness of a subsequent decortication operation involving splitting of the stalk by shaping the stalk in a manner which assists ease of splitting of the stalk.

A decorticating step according to the present invention is capable of facilitating separation of the fibrous outer from the hurd of a plant stalk.

A decorticating step according to the present invention may include a separating step. The separating step may include a stripping step. The arrangement is preferably such that the outer fibre and hurd of the stalk are separated by stripping the hurd from the fibre. In one embodiment the outer fibrous surface of the stalk is passed over a source of vacuum, whereupon in a substantially simultaneous stripping step the hurd is stripped from the fibre whereby to separate the fibre from the hurd.

Separated fibre according to the invention may then be cut into discrete lengths in suitable manner.

A processing apparatus for a plant stalk according to the present invention includes bond rupture means whereby to facilitate the rupture of bonds between the fibre and the hurd of the stalk for a decortication operation. The bond rupture means may include a plurality of rupture rollers. The arrangement may be such that following discharge of the stalks from primary rollers according to the invention the stalks are delivered to the rupture rollers whereby to rupture the bond between the outer fibre and the inner core of the stalk by applying constant or varying pressure to a surface of the stalk. An outer surface of a rupture roller according to the invention may be configured to enhance the rupturing action caused by the application of pressure to the stalk. The outer surface of a rupture roller may include vanes, fingers, ridges or lugs. The vanes, lingers, ridges or lugs may be outwardly projecting. Other fibre/hurd bond rupturing arrangements are envisaged as being within the scope of the present invention.

A processing apparatus for a plant stalk according to the present invention may include shape modification means for modifying the shape of the stalk. The shape modification means may take any suitable form. The shape modification means may include pressing rollers. The pressing rollers may be counter-rotating. The pressing rollers may in one embodiment alter the cross-sectional profile of the stalk whereby the substantially circular stalk is passed between the pressing rollers and pressed substantially flat. The shape modification means is in one embodiment located above decorticating means according to the invention.

Splitting means according to the invention may take any suitable form. In one embodiment the splitting means comprises a flying band saw or reciprocating knife whereby to split a stalk longitudinally. Other splitting means are envisaged as being within the scope of the present invention.

Decorticating means according to the invention may include a decorticating roller assembly. The decorticating roller assembly may include a vacuum source. The vacuum source may be in the form of a vacuum roller. The vacuum roller may be perforated. The vacuum roller may be an anvil roller. The arrangement may be such that a split stalk is passed over the surface of the vacuum roller whereby the vacuum roller is positioned relative to the stalk such that the fibrous surface of the stalk is drawn on to the roller surface by the vacuum. A further rotating roller such as a toothed roller associated with the vacuum roller may be positioned so as to strip the hurd from the fibre as the split stalk passes over or through an associated pair of rollers.

A pair of vacuum rollers and associated toothed rollers may be positioned at a downstream end of splitting means according to the invention whereby one half of the split stalk is acted upon by one vacuum roller and an associated toothed roller, and the other half of the split stalk is acted upon by the other vacuum roller and its associated toothed roller. Separated fibre according to the invention may be cut into discrete lengths following decortication. This may be achieved by a severing device. The cutting device may be reciprocating. The cutting device may have a plurality of cutting blades whereby to simultaneously cut a stalk of fibre into a predetermined length or lengths.

In an alternative embodiment, separated fibre may be passed to a battery of spinning distaffs or spools.

Separated fibre may be subjected to digestion following which it may be processed into yarn or hackled.

The present invention provides in another embodiment a method for harvesting and processing a crop. The crop may be hemp. A particularly preferred hemp crop is that of the genus Cannabis sativa L and species thereof. Other crops are envisaged for processing in accordance with the present invention, including Kenaf, Ramie, sugar cane and other bast crops.

A harvesting method according to the invention includes the steps of gathering a plurality of stalks from a crop, severing the stalks from the ground, and decorticating the stalks whereby to separate the fibre of the stalk from the hurd, the harvesting and processing being carried out when the crop is green.

The present invention provides in another embodiment a harvesting and processing apparatus suitable for carrying out the methods described. The apparatus includes gathering means for gathering a plurality of stalks from a crop, severing means for severing at least some of the gathered stalks from the ground, and decorticating means for separating the fibre of the stalk from the hurd.

Methods for harvesting and processing according to the present invention may include a number of operations whereby to render the harvested and processed crop in a form suitable for a further refining operation. The arrangement is preferably such that methods according to the invention enable the crop to be processed in an integrated operation from initial removal from the field in which it is grown through to discrete product suitable for further refining.

For example, fibre produced according to methods of the present invention is preferably capable of being used as a feed material for further refining.

Further refining according to the present invention includes any process which refines the fibre and/or hurd. Examples of further refining include any process which requires a fibrous feedstock, such as pulp and papermaking, textile production, clothing or footwear production, rope production and so on. Other further refining operations for the fibre and/or hurd are envisaged within the scope of the present invention. A harvesting method according to the present invention may include a reaping operation. A reaping operation according to the invention may include gathering a plurality of stalks and severing at least some of the stalks from the ground.

A gathering step according to the invention may take any suitable form. In one embodiment, the gathering step comprises capturing a plurality of stalks by mechanical or other means, such as by sweeping a gathering arm through an arc whereby to capture the plurality of stalks.

The gathering step may include the step of isolating a plurality of plant stalks from the crop. Preferably a sufficient number of stalks are gathered in a sweep lo facilitate a further operation being performed on the stalks thus gathered and isolated. Preferably the isolation step is such as to retain a sufficient number of stalks for a further processing operation.

A gathering step according to the invention may be such as to separate the stalks into a plurality of discrete segments. The gathering step may accordingly be capable of isolating a discrete number of stalks in a sweep of a gathering arm whereby to form a segment of stalks. It has been found to be more efficient in a particularly preferred embodiment to gather a discrete segment of stalks for delivery to further processing steps.

A harvesting method according to the invention may include a primary stripping step. The primary stripping step may be such as to strip leaves and/or branches of the stalks from the stalks whereby to facilitate processing of the stalks. A primary stripping step may include contacting the stalks with primary stripping means. In one embodiment primary stripping means are moved in a vertical direction relative to the stalks following gathering and isolation of the stalks whereby to strip leaves and/or branches of the stalks from the stalks. Other primary stripping arrangements are envisaged within the scope of the present invention.

A severing step according to the invention may take any suitable form. Preferably the severing step is such as to separate a plurality of stalks from the root system of a corresponding plurality of plants. Preferably the severing step includes severing the stalks as close to the ground as possible. The severing step may be in the form a mechanical scything operation. The severing step may follow the step of gathering and/or isolating a plurality of stalks. It has been found to be generally more efficient to gather and isolate the stalks and to subsequently cut the stalks thus gathered.

A harvesting method according to the present invention may include the step of incrementally advancing over or through the crop whereby to sequentially harvest the crop for processing. Incremental advancement may be accomplished by step-wise or sequential mechanical movement of a harvesting apparatus according to the invention over or through the crop. The increments may be adjustably selected according to the density of the crop and/or the crop planting pattern.

A harvesting method according to the present invention may include a further stripping step. The arrangement may be such that following severing of the stalk from the ground the stalk is stripped of leaves and/or branches remaining on the stalk for a further processing operation.

In a particularly preferred gathering sequence according to the invention, a plurality of stalks are gathered into a plurality of segments by a sweep of a gathering arm of apparatus according lo the invention through a crop. The stalks are subjected lo a primary stripping step to untangle the stalks and to remove extraneous matter from the stalk. The stalks are then severed in a severing step and a segment of stalks is passed incrementally to a further stripping step.

It will be appreciated that whilst there are a number of discrete steps in the methods described, one or more of the steps may be combined into a single step. In addition, the order of the steps may vary depending on a number of factors including the type of crop to be harvested, growing or climatic conditions, site-specific limitations or requirements, etc.

It will be appreciated that each step in methods according to the invention can be repeated as necessary. It will also be appreciated that methods according to the invention may be operated in continuous fashion whereby to harvest a crop in a single integrated operation.

Harvesting and processing apparatus according to the invention may include a number of components. The apparatus may integrate a number of, or all, components of the apparatus. The components may be moving components. The arrangement may be such that the components are movable relative to one another. The components may interact whereby to enable harvesting and processing of the crop.

The arrangement is preferably such that apparatus according to the invention performs a plurality of processing functions on the crop, enabling the crop to be processed in an integrated operation from initial removal from the field in which it is grown to discrete product suitable for further refining.

Components according to the invention may be associated with a shaft. A component according to the invention may be mounted on the shaft. A component according to the invention may be movable relative to the shaft. The component may be pivotable relative to the shaft. The component may be journalled for rotation relative to the shaft. The shaft may be substantially vertical. The shaft may be rotatable about an axis. Preferably the shaft is rotatable about its longitudinal axis. The shaft may be movable in a vertical direction. The shaft may be associated with another part of the apparatus, such as by mounting on part of the apparatus. The shaft may be journalled for rotation relative to another part of the apparatus.

Gathering means according lo the present invention may include at least one gathering arm. The arrangement may be such that the gathering arm gathers a plurality of stalks in a sweep of the arm through a crop.

The gathering arm may be mounted on a shaft of apparatus according to the invention. The gathering arm may be movable relative to the shaft. The gathering arm may pivot relative to the shaft. The arrangement is preferably such that the arm is mounted for movement in a substantially horizontal plane. In a particularly preferred embodiment the arm is pivotably mounted on the shaft and movable in a substantially horizontal plane whereby to gather a plurality of stalks. The gathering arm may be curved whereby to facilitate passage through a crop of stalks in a stalk gathering operation.

The gathering arm may be segmented. In one embodiment the gathering arm comprises a plurality of segments. A segment according to the invention is preferably capable of isolating a discrete number of stalks in a sweep of the gathering arm whereby lo form a segment of stalks.

A segment according to the invention may be associated wilh a keeper roller. A keeper roller according to the invention may be arranged to retain gathered stalks in a segment of the gathering arm. The keeper roller may be movable relative to the gathering arm. In one embodiment the keeper roller is adjustably movable towards and away from stalks held by the gathering arm. The keeper roller may contact stalks gathered by the gathering arm whereby to assist in urging the stalks to nest in the gathering arm.

A gathering arm according to the invention may be recessed, grooved or fluted. The recesses, grooves or flutes may be such as to receive at least part of a stalk gathered by the gathering arm whereby a stalk is capable of nesting in a recess, groove or flute of the gathering arm. Other stalk nesting arrangements are envisaged within the scope of the invention.

Gathering means according to the invention may include a second arm. The second arm may be a composite arm. A composite arm according to the invention preferably constitutes with the gathering arm a stalk isolating means. The gathering arm and composite arm may interengage. The composite arm may be spaced from the gathering arm. The composite arm may be vertically spaced from the gathering arm. The composite arm may be mounted on a shaft of the apparatus. The composite arm may be movable relative to the shaft. The composite arm may pivot relative to the shaft. The gathering arm and composite arm may share a common shaft. The arrangement is preferably such that the composite arm is mounted for movement in a substantially horizontal plane. In a particularly preferred embodiment the composite arm is pivotably mounted on the shaft and movable in a substantially horizontal plane whereby with the gathering arm to isolate the plurality of stalks gathered by the gathering arm. The composite arm may include nesting means. The nesting means may be configured to nest a stem of a stalk within the nesting means.

A composite arm according to the present invention may include an associated guide plate. The plate may include a pair of arms defining forks or tines whereby to assist in nesting of the stalk in a gathering arm according to the invention. The forks or tines may be recessed or curved. The forks or tines may be spring loaded to bias the forks or tines towards a stalk. A guide plate according to the invention may be mounted on a platform.

A composite arm and its associated guide plate may be movable relative to a stalk. In one embodiment, the composite arm and guide plate are movable vertically relative to the stalk whereby to untangle the stalk from adjacent stalks and to strip leaves and/or branches from the stalk.

The guide plate or platform may be mounted on a shaft of the apparatus. The guide plate or platform may be movable relative to the shaft. The guide plate or platform may pivot relative to the shaft. The arrangement is preferably such that the platform is mounted for movement in a substantially horizontal plane. In a particularly preferred embodiment the guide plate is pivotably mounted on the shaft for rotation relative to the shaft and movable in a substantially horizontal plane. The arrangement is preferably such that the guide plate is movable in a substantially horizontal plane about the shaft whereby to seat or locate the stalks in the recesses, grooves or flutes carried by the gathering arm.

Gathering means according to the invention may include a primary stripping operation for primary stripping of extraneous matter such as leaves and/or branches from the stalk. In one embodiment, the primary stripping operation comprises moving a composite arm according to the invention and its associated platform in a vertical direction relative to the stalks following gathering of the stalks whereby to strip leaves and/or branches from the stalks.

Severing means according lo the invention may take any suitable form. Preferably the severing means is such as to separate a plurality of stalks subjected to primary stripping from the root system of a corresponding plurality of plants. The arrangement may be such that the severing means cuts the stalks at or near to the ground. The severing means may be mounted on a shaft of the apparatus. The severing means may be movable relative to the shaft. The severing means may pivot relative to the shaft. The arrangement is preferably such that ihe severing means is mounted for movement in a substantially horizontal plane. In a particularly preferred embodiment the severing means is pivotably mounted on the shaft for rotation relative to the shaft and movable in a substantially horizontal plane. The arrangement is preferably such that the severing means is movable in a substantially horizontal plane about the shaft. In one embodiment the severing means is in the form of a blade or scythe which sweeps as close to the ground as possible in a substantially horizontal plane whereby to sever at least some of the plurality of stalks held by the gathering arm from their respective root systems.

Gathering means according to the invention may include one or more primary rollers. The primary rollers may be counter-rotating. The primary rollers may be grabbing rollers. The arrangement may be such that following severing a stalk is passed between a pair of primary rollers in the form of grabbing rollers and stripped of leaves and/or branches remaining on the stalk for a further processing operation. The primary rollers may be arranged to accommodate varying sizes of stalks whereby a surface of a primary roller is adjustable lo permit contact between the stalk and the primary roller surface.

The primary rollers may be arranged to receive a plurality of stalks delivered by the gathering arm to a location adjacent the entry point ot the rollers. In one embodiment, the primary rollers are counter-rotating and the longitudinal axes of the primary rollers are substantially horizontal. In this embodiment, the gathering arm delivers a segment of gathered stalks to a point above the counter-rotating primary rollers whereby the stalks are released by the gathering arm and are passed downwardly through the primary rollers and are subjected to a further stripping operation for further processing. The gathering arm may deliver sequential segments of gathered stalks to the primary rollers for processing as described.

In a particularly preferred gathering operation according to the invention, a plurality ol stalks are gathered by a sweep of the gathering arm through a crop. A composite arm co-operates with the gathering arm to isolate the plurality of stalks from the crop into a plurality of segments. The composite arm is subsequently elevated to perform a primary untangling and primary stripping operation of extraneous matter from the stalk. The stalks are then severed by the severing means and a segment of stalks is passed incrementally to a point above primary rollers associated with the gathering means and delivered downwardly to the primary rollers for further stripping. Gathering means according to the invention may include sensing means to sensor the position of the apparatus relative to the crop to be harvested and processed. A sensing means may provide an operator with an audible or visual indication of the proximity of the apparatus to the crop.

Movement of components of the apparatus according to the invention may be hydraulically or pneumatically driven.

An apparatus according to the present invention may include incremental advancement means for incrementally advancing apparatus according to the invention over or through the crop whereby to sequentially harvest the crop.

An apparatus according to the present invention may include a source of motive power. The motive power may be provided by an engine and drivers cab which may form an integral part of the apparatus according to the invention or by a separable unit such as a prime mover. In this latter arrangement the apparatus provided by the present invention preferably comprises a trailer which includes means for operably coupling the trailer to a prime mover and optionally means for supporting the trailer when the prime mover is uncoupled .

In a particularly preferred embodiment, a harvesting and processing apparatus according to the invention includes gathering means comprising a movable segmented gathering arm for gathering a plurality of stalks from a crop, a composite arm for isolating with the gathering arm the plurality of stalks, the composite arm being movable in a vertical direction whereby to untangle the stalks and strip leaves and/or branches from the stalks, severing means for severing at least some of the gathered stalks from the ground, primary rollers to which a segment of stalks is incrementally delivered for further stripping, bond rupture means comprising a plurality of rollers for applying constant and/ or varying pressure to a surface of the stalk whereby to rupture bonds between fibre of the stalk and the hurd, stalk splitting means for splitting the stalk substantially longitudinally, and decorticating means for separating fibre of the stalk from the hurd. BRIEF DESCRIPTION OF PREFERRED EMBODIMENT

The present invention will now be described with reference to particularly preferred embodiments in which:

Figure 1 is a schematic block diagram of a method in accordance with one embodiment of the present invention;

Figure 2 is a cross-sectional view from the top of apparatus according to one embodiment of the present invention;

Figure 3 is a cross-sectional elevation of a stalk gathering and isolating component of apparatus according to one embodiment of the present invention;

Figure 4 is a cross-sectional elevation of bond rupture means of apparatus according to one embodiment of the present invention; and

Figure 5 is a cross-sectional elevation of decorticating means of apparatus according to one embodiment of the present invention.

It will be appreciated that whilst the embodiment of Figure 1 shows a number of discrete steps in the methods described, one or more of the steps may be combined into a single step. In addition, the order of the steps may vary depending on a number of factors including the type of crop to be treated, growing or climatic conditions, site-specific limitations or requirements, etc.

It will also be appreciated that whilst the description of particularly preferred embodiments relates to the harvesting of hemp crops, the harvesting of other crops is also envisaged as being within the scope of the present invention.

Turning to the drawings, Figure 1 shows a schematic block diagram of a method for harvesting a hemp crop. Harvesting of a crop of hemp 1 growing in a field is commenced following observation of the growth pattern of the hemp and selecting a time for harvesting in accordance with the timing of a predetermined phase of growth of the plants.

Harvesting of crop 1 includes a gathering step 10. Gathering step 10 includes gathering a plurality of crop stalks from the field in a sequential harvesting operation The gathering step comprises capturing a plurality of stalks by sweeping a gathering arm according to the invention through a substantially horizontal arc whereby lo gather and isolate the plurality of stalks. This is followed by a primary stripping step to untangle the stalks from adjacent stalks and to strip extraneous matter such as leaves from the stalks.

A severing step comprises severing at least some of the gathered stalks from the ground. The severing step includes scything the gathered stalks as close to the ground as possible whereby to separate a plurality of stalks from the root system of a corresponding plurality of plants. The severed stalks may be subjected to a further stripping step for a further processing operation.

Following gathering, primary stripping and severing of the stalks, the cut stalks are subjected to a bond rupturing step 11. Subjecting the stalks to a bond rupturing step 11 is intended to loosen the adhesive bond between the outer fibre of the stalk and the inner core or hurd whereby lo facilitate separation of the fibre from the hurd in a subsequent decorticating step. Bond rupturing step 11 includes applying constant or varying pressure to a surface of the stalk to distort the stalk.

Following the rupture of bonds between the fibre and hurd of the stalk, the stalk is transferred to a shape modification step 12. The shape of the generally circular cross- section stalk is modified by passing the stalk through a pair of pressing rollers whereby the stalk is pressed substantially flat.

Alter the shape of the stalk has been modified, the stalk is transferred to a decorticating step 13. Decorticating step 13 includes a stalk splitting step 14 and a separating step 15. A splitting step 14 includes parting or opening the stalk to facilitate separation of the fibre from the hurd in subsequent separating step 15. The stalk is split longitudinally by passing the stalk in a longitudinal direction past a flying band saw or knife.

Separating step 15 includes a stripping step whereby the outer fibre and the hurd of the stalk are separated by stripping the hurd from the fibre.

Separated fibre 16 may then be cut into discrete lengths for further refining. Hurd 17 following stripping may also be collected for further refining.

Figure 2 shows a top view of apparatus according to one embodiment of the invention capable of moving through a crop of stalks 25 in the direction indicated by arrow A. The apparatus includes gathering means 20 and processing means 70. Processing means 70 includes bond rupture means and decorticating means (not shown in Figure 2, but see Figures 4 and 5).

Gathering means 20 includes a gathering arm 22 rotatably mounted on shaft 21 and movable in a substantially horizontal plane in a reciprocal direction indicated by arrow B. Gathering arm 22 includes a curved member 23 to facilitate passage through the crop and arranged to gather a plurality of stalks in a sweep of the gathering arm 22 through a crop or along a flank of a crop of stalks 25. Curved member 23 with keeper rollers 24 defines a plurality of segments of the gathering arm 22. Keeper roller 24 is arranged to retain gathered stalks in a segment of gathering arm 22, and is adjustably movable towards and away from the stalks held by gathering arm 22 whereby to assist in urging the stalks lo nest in recesses, grooves or flutes (not shown) in curved member 23.

Composite arm 26 is mounted for rotation relative to shaft 21. Composite arm 26 is movable in a substantially horizontal plane whereby with the gathering arm 22 a plurality of stalks can be isolated.

Spring-loaded guide plate 27 mounted on platform 28 is associated with composite arm 26 whereby on gathering and isolating a segment of stalks, composite arm and associated guide plate 27 are arranged to elevate to untangle stalks from adjacent ones and to strip extraneous matter such as leaves from the stalks.

In a gathering and severing operation the stalks are gathered by gathering arm 22, elevated by composite arm 26 to strip leaves and severed by severing means (not shown), following which the stalks are transferred to a point above primary counter- rotating rollers 31, 32, and subsequently delivered downwardly through primary rollers 31, 32 and subjected to further stripping. Primary rollers 32 is tensioned at 33 to bias the primary rollers towards one another to assist in the stripping operation.

Figure 4 shows bond rupture means of apparatus according to one embodiment of the present invention. From primary rollers 31, 32 the stalk(s) are delivered to bond rupture means, which in the embodiment shown comprises a plurality of rollers 34, 35, 36, 37, 38 defining a tortuous path for stalk 30. The arrangement is such that rollers 34, 35, 36, 37, 38 rupture the bond between fibre and hurd of stalk 30 by the application of constant or varying pressure to the surface of stalk 30. An outer surface of each roller 34, 35, 36, 37, 38 is configured to include outwardly projecting vanes, fingers, ridges or lugs (not shown) to enhance the bond rupturing action of the rollers caused by the application of pressure to stalk 30.

Following a bond rupturing operation, stalk 30 is passed between shape modification means in the form of counter-rotating pressing rollers 39, 40 whereby to press stalk 30 substantially flat.

Flattened stalk 30 is subsequently passed to decorticating means 50 in the form of a decortication roller assembly (Figure 5). Decorticating means 50 includes splitting means 41 in the form of a flying band saw or knife which splits stalk 30 longitudinally as the stalk traverses the saw. It will be seen from Figure 5 that the stalk 30 is split into two parts 30a, 30b, whereupon the respective parts 30a, 30b are transferred to respective vacuum rollers 42, 44 having associated toothed rollers 43, 45. The arrangement is such that the stalk part 30a, 30b is passed between a vacuum roller and its associated toothed roller. The stalk part 30a, 3ϋb is oriented whereby the outer fibrous surface of stalk part 30a, 30b is exposed to the vacuum surface of vacuum roller 42. 44 and temporarily sucked onto the roller surface. Substantially simultaneously toothed roller 43, 45 located adjacent a corresponding vacuum roller strips the hurd from the stalk part 30a, 30b. whereby to separate the fibre from the hurd of the stalk.

Following stripping from the fibre the hurd is deposited in a holding vessel 46 (only one shown) which may surround a toothed roller 43, 45. Separated fibre 3ϋc may be transferred to a cutting station (not shown) to cut the fibre into discrete lengths for further refining, or optionally delivered to a battery of spinning distaffs or spools. The fibre may then be subjected to digestion, following which it may be processed into yarn or hackled.

In use, the present invention is designed to employ a wheel or caterpillar mounted machine to approach a crop of growing stalks for reaping along a flank for a chosen width of swath, and provided with incremental advancement means for moving forwardly a variably adjusted distance to allow a horizontally swivelling arm to embrace an acceptable amount of stalks to be accommodated between the swivelling arm and a composite sectioned inner arm to be able to clamp the free standing stalks against the inner side of the swivelling arm.

When this is accomplished an overhead layer of the swivelling arm is immediately projected upward to untangle any intertwined stalks and strip off any unwanted leaves from the stalks.

Following primary stripping of the stalks, a swivelling arm mounted cutter is traversed as close to the ground as possible.

This arrangement permits the swivelling arm members to be quickly elevated to the preferred working heights so that the now amputated stalks may be progressively indexed to pass between the receiving rollers located above the decorticating roller assembly.

In order to give maximum disruption to the natural adhesion of the outer fibrous film and woody inner matter, a double pair of orbiting multiple rollers are provided whereby the maximum distortion of stalks is achieved to mechanically rupture the natural adhesion of the hurd and fibrous sections.

By mounting gear driven rollers in a lantern assembly method and driving those rollers to travel on bearings in between gear toothed flanges in orbital fashion and having an interacting path causing maximum distortion of natural state of stalks, severe disturbance is achieved in weakening the adhesive strength of otherwise related matter. Immediately the stalks are located the rollers close onto the stalks and thrust them down into the decorticating roller assembly to be rapidly swallowed and delivered into a space between a pair of rollers having a performed peripheral surface which pinches the stalks firmly and discharges them on to a band saw or knife to split their ends apart and guides their ends directly between the perforated rollers and rollers fitted with vanes grouped radially around their periphery which, due to the high roller speeds, removes the hurd from the fibrous outer thus completing the decortication.

As the high speed vanes dislodge the hurd it is flung into a receptacle lor subsequent transport to processing into various products as it is a valuable waste. As the fibrous outer is sucked against the perforated anvil roller, as a would be anvil it is carried out forward until it is flung off the suction section by the pressure section and fully delivered into the mouth of a vacuum transport tube to be collected in a suitable container for delivery to further factory processing.

The present invention has the advantage that a value-added commodity can be produced by methods and apparatus according to the invention, providing the potential for greater financial returns to the farmer as compared to conventional crop harvesting methods. Furthermore, methods and apparatus according lo Ihe invention permit processing of the crop in an integrated operation.

While it has been convenient to describe the invention herein in relation to particularly preferred embodiments, it is to be appreciated that other constructions and arrangements are considered as falling within the scope of the invention. Various modifications, alterations, variations and/or additions to the constructions and arrangements described herein are also considered as falling within the scope and ambit of the present invention.

Claims

1. A method for processing a plant stalk having a fibrous outer part and an inner hurd, processing being commenced when said stalk is green, the method including the steps of facilitating rupture of bonds between said fibre and said hurd in a bond rupturing slep, splitting said stalk substantially longitudinally whereby to expose said hurd, and decorticating the split stalk whereby to separate said fibre from said hurd.

2. A method according to claim 1, and further including the step of modifying the shape of said stalk prior to splitting said stalk whereby pressure is applied to the outer surface of said stalk whereby to modify the cross-sectional shape of said stalk to facilitate splitting of said stalk.

3. A method according to claim 2, wherein said shape modifying step is carried out following said bond rupturing step.

4. A method according to claim 1, wherein said bond rupturing step includes distorting said stalk by applying constant or varying pressure to the outer surface of the stalk whereby to facilitate loosening of adhesive bonds between said fibre and said hurd.

5. A method according to claim 1, wherein said decorticating step includes stripping said hurd from said fibre in a stripping step.

6. A method according to claim 1, wherein said plant stalk is derived from plants of the genus Cannabis sativa L and species thereof.

7. Apparatus for processing a plant stalk having a fibrous outer part and an inner hurd, the processing of said stalk being commenced when the stalk is green, the apparatus including bond rupture means to facilitate the rupture of bonds between said fibre and said hurd, splitting means for splitting said stalk substantially longitudinally, and decorticating means for the split stalk whereby to separate said fibre from said hurd.

8. Apparatus according to claim 7, and further including shape modification means for said stalk whereby to modify the cross-sectional shape of said stalk prior to splitting said stalk.

9. Apparatus according to claim 8, wherein said shape modification means comprises a pair of opposed rollers whereby said stalk is passed between said rollers and pressed substantially flat for subsequent splitting of said stalk.

10. Apparatus according to claim 8, wherein said shape modification means is located intermediale said bond rupture means and said splitting means.

11. Apparatus according to claim 7, wherein said splitting means comprises a reciprocating knife.

12. Apparatus according to claim 7, wherein said bond rupture means comprises a plurality of rupture rollers whereby to rupture the bond between said fibre and said hurd by applying constant or varying pressure to a surface of said stalk.

13. Apparatus according to claim 12, wherein the outer surface of said rupture rollers includes outwardly projecting vanes, fingers, ridges or lugs.

14. Apparatus according to claim 12, wherein said rupture rollers are arranged whereby to define a tortuous path for said stalk to facilitate rupture of said bonds.

15. Apparatus according to claim 7, wherein said decorticating means includes stripping means for stripping said hurd from said fibre.

16. Apparatus according to claim 15, wherein said stripping means comprises at least one toothed roller, the teeth of said toothed roller arranged to strip said hurd from said fibre as said split stalk passes said toothed roller.

17. Apparatus according to claim 7, wherein said decorticating means includes a decorticating roller assembly, said decorticating roller assembly comprising at least one vacuum roller and at least one rotating roller associated with said vacuum roller, said vacuum roller positioned relative to the path of travel of said stalk such that the outer surface of said stalk is drawn towards the surface of said vacuum roller, said rotating roller including a plurality of teeth on an outer surface thereof and positioned relative to the path of travel of said stalk so as to strip said hurd from said fibre as said stalk passes between said rollers.

18. Apparatus according to claim 17, wherein a pair of vacuum rollers and associated toothed rollers are positioned relative to the path of travel of said stalk whereby one half of the split stalk is acted upon by a first pair of a vacuum roller and associated toothed roller whereby to separate said hurd from said fibre and the other half of said split stalk is acted upon by a second pair of a vacuum roller and associated toothed roller whereby to separate said hurd from said fibre.

19. A method for harvesting and processing a crop, said crop comprising plants having stalks comprising a fibrous outer part and an inner hurd, said harvesting and processing being commenced when said stalks are green, said method including the steps of gathering a plurality of stalks from said crop, severing said stalks from the ground, and decorticating said stalks whereby to separate said fibre from said hurd.

20. Apparatus for harvesting and processing a crop, said crop comprising plants having stalks comprising a fibrous outer part and an inner hurd, said harvesting and processing being commenced when said stalks are green, said apparatus including gathering means for gathering a plurality of stalks from said crop, severing means for severing said stalks from the ground, and decorticating means for said stalks whereby to separate said fibre from said hurd.

21. Apparatus for harvesting and processing plant stalks having a fibrous outer part and an inner hurd from a crop, said harvesting and processing commencing when said stalks are green, said apparatus including gathering means comprising a gathering arm for gathering a plurality of plant stalks from said crop, severing means for severing at least some of the gathered stalks from the ground, primary rollers to which a segment of stalks is incrementally delivered for stripping leaves and/or branches from said stalks, bond rupture means comprising a plurality of rollers for applying constant or varying pressure to a surface of said stalk whereby to rupture bonds between said fibre and said hurd, stalk splitting means for splitting said stalk substantially longitudinally, and decorticating means for separating said fibre from said hurd.

22. Apparatus according to claim 21, and further including a composite arm for isolating with the gathering arm the plurality of stalks, the composite arm vertically movable relative to said stalks whereby to untangle said stalks and strip leaves and/or branches from said stalks.

23. In a method for harvesting and/or processing plant stalks derived from the genus Cannabis sativa L and species thereof, the improvement comprising commencing said harvesting and/or processing just prior to the commencement of seed development of the plant or just as flowering of said plant is beginning.