Extraction apparatus

Abstract

An apparatus 100 for extracting one or more elementary fibres from a plant feedstock 200, the apparatus comprising: a first drive assembly 101; a second drive assembly 102; and a first separation asse

Description

Fseid of the invention The present invention relates to an apparatus and method for extracting elementary fibres from plant feedstock. More specifically., the invention relates to an apparatus and method for extracting elementary fibres from the bast region of a plant stem, or from a fibrous plant leaf. Background The extraction of fibres from plant material is a critical process in various industries, including textiles, paper manufacturing, and bio composites. Traditionally, this process involves several labour-intensive and time-consuming steps, such as retting, scutching, and carding. These conventional methods often result in inconsistent fibre quality and significant material loss. Retting in particular is generally very time consuming, expensive and can produce significant amounts of liquid waste that can be difficult to dispose of safely. There is a need, therefore, for an apparatus that can consistently produce high-quality fibres with minimal manual intervention and reduced processing time. In particular, there is a need for an improved extraction method and apparatus that can avoid the need for pre-processing, such as retting. Such an apparatus would not only enhance productivity but also improve the sustainability of fibre production by minimizing the additional waste and energy consumption associated with alternative fibre extraction processes. The present invention addresses these needs by providing an innovative apparatus designed to extract fibres from plant material more effectively, allowing for improved efficiency and for the use of a broader range of plant feedstocks and with minimal (if any) pre-processing required. This apparatus is configured to ensure the efficient separation of fibres while maintaining their structural integrity. The invention aims to streamline the fibre extraction process, offering a reliable solution for industries reliant on high-quality plant fibres. Summary of the invention According to a first aspect of the disclosure, there is provided apparatus for extracting one or more elementary fibres from a plant feedstock, the apparatus comprising: a first drive assembly; a second drive assembly; and a first separation assembly disposed between the first and second drive assemblies; the first and second drive assemblies each being configured to move the plant feedstock through the apparatus; and the first separation assembly being configured to apply a separating force to the plant feedstock in order to extract one or more elementary fibres. An apparatus according to the first aspect is beneficial as it allows for quick and efficient extraction of fibres from a plant feedstock. The apparatus allows for a high proportion of the fibres to be extracted from the plant feedstock with minimal damage to the fibres, and with a high degree of automation possible. An apparatus according to the first aspect is further beneficial as it allows for an extremely wide range of plant feedstocks to be used. In particular, the apparatus is able to extract fibres from dry, rehydrated, fresh, and / or pre-processed plant feedstock. Furthermore, the apparatus is able to extract fibres from softer and less durable plant feedstocks, such as potato plant stems, that cannot be processed using existing options, such as decorticators. In an embodiment, there is provided an apparatus wherein the first drive assembly comprises a pair of rollers configured to grip the plant stem, thereby to move the plant feedstock through the apparatus. A first drive assembly arranged in this manner ensures consistent movement of the plant feedstock through the apparatus, facilitating smooth and efficient extraction of fibres from the feedstock. In an embodiment, there is provided an apparatus wherein the first drive assembly is configured to facilitate movement of the plant feedstock into and at least partially through the first separation assembly. This helps the separation assembly to quickly and efficiently extract fibres from the plant feedstock. Further, the force imparted by the first drive assembly can assist with the separation of the fibres by the first separation assembly. In an embodiment, there is provided an apparatus wherein the second drive assembly comprises a pair of rollers configured to grip the plant feedstock, thereby to move the plant feedstock through the apparatus. A second drive assembly arranged in this manner ensures consistent movement of the plant feedstock through the apparatus, facilitating smooth and efficient extraction of fibres from the feedstock In an embodiment, there is provided an apparatus wherein the second drive assembly is configured to facilitate movement of the plant feedstock out of the first separation assembly. This helps the separation assembly to quickly and efficiently extract fibres from the plant feedstock. Further, the force imparted by the second drive assembly can assist with the separation of the fibres by the first separation assembly. In an embodiment, there is provided an apparatus wherein the first separation assembly is configured to apply a separation force in a direction substantially opposite to the direction of motion of the plant feedstock through the apparatus. Applying the separation force in this manner enhances the effectiveness of fibre extraction by counteracting the plant feedstock's movement, leading to more efficient separation. In an embodiment, there is provided an apparatus wherein the first separation assembly comprises a pair of rollers. Using rollers in this manner facilitates controlled and consistent application of separating force, improving the quality and efficiency of fibre extraction. In an embodiment, there is provided an apparatus wherein the rollers of the first separation assembly are configured to be rotatable in order to apply a separation force to the plant feedstock in substantially the opposite direction to the motion of the plant feedstock through the apparatus. Rotatable rollers in the first separation assembly allow for precise force application, enhancing the effectiveness and quality of fibre separation. In an embodiment, there is provided an apparatus wherein the first separation assembly is configured to apply a shearing force to the plant feedstock. Applying a shearing force to the plant feedstock ensures effective separation of fibres without excessive damage, preserving fibre integrity. In an embodiment, there is provided an apparatus wherein the first separation assembly is configured to apply a splitting and / or peeling force to the plant feedstock. The ability to apply splitting and / or peeling forces provides versatility in handling different types of plant feedstock and for effective extraction of different fibres, making the apparatus adaptable to various materials and requirements. In an embodiment, there is provided an apparatus further comprising a removal assembly configured to remove the one or more separated elementary fibres from the first separation assembly. The removal assembly ensures efficient collection of separated fibres, reducing the need for manual handling and improving overall process efficiency. In an embodiment, there is provided an apparatus wherein the removal assembly comprises one or more brushes. Brushes in the removal assembly provide gentle yet effective cleaning and removal of fibres from the separation assembly, maintaining fibre quality and enhancing the efficiency with which extracted fibres are collected. In an embodiment, there is provided an apparatus wherein the removal assembly comprises one or more rotatable brushes. Rotatable brushes enhance the removal process by ensuring thorough cleaning and fibre collection, improving the efficiency of the apparatus. In an embodiment, there is provided an apparatus wherein the first drive assembly is configurable to apply a crushing force to the plant feedstock. By applying a crushing force, the plant feedstock can be made substantially flat, improving the efficiency with which the separation assembly can extract fibres from the plant stock. In an embodiment, there is provided an apparatus further comprising one or more guide assemblies configured to, in use, guide the plant feedstock through the apparatus. Guide assemblies ensure precise alignment and movement of the plant feedstock through the apparatus, reducing the risk of misalignment and damage. In an embodiment, there is provided an apparatus comprising a first guide assembly positioned between the first drive assembly and the first separation assembly, the first guide assembly being configured to, in use, guide the plant feedstock into the first separation assembly. The first guide assembly ensures smooth entry of the plant feedstock into the first separation assembly, enhancing process efficiency and reducing the risk of blockages. In an embodiment, there is provided an apparatus comprising a second guide assembly disposed between the first separation assembly and the second drive assembly, the second guide assembly being configured to, in use, guide the plant feedstock into the second drive assembly. The second guide assembly ensures that the plant material is able to smoothly transition between the first separation assembly and the second drive assembly, enhancing process efficiency and reducing the risk of blockages. In an embodiment, there is provided an apparatus further comprising a second separation assembly. The inclusion of a second separation assembly allows for additional processing stages, improving the thoroughness and quality of fibre extraction, and thus the overall efficiency of the apparatus. In an embodiment, there is provided an apparatus wherein the second separation assembly is disposed between the first separation assembly and the second drive assembly. Positioning the second separation assembly between the first separation and second drive assemblies allows for continuous and efficient processing, enhancing overall productivity. The second separation assembly may advantageously allow for additional elementary fibres to be extracted from the plant feedstock. In an embodiment, there is provided an apparatus further comprising a third drive assembly, wherein the second separation assembly is disposed between the second drive assembly and the third drive assembly. The third drive assembly provides additional movement control, enhancing the overall efficiency and effectiveness of the apparatus by ensuring consistent feedstock movement. Positioning the second separation assembly between the second drive assembly and the third drive assembly allows for continuous control over the motion of the plant feedstock while the plant feedstock is being moved through each of the separation assemblies. In an embodiment, there is provided an apparatus wherein: the plant feedstock is a plant stem comprising a bast region; and the one or more elementary fibres are extracted from the bast region of the plant stem. Fibres extracted from the bast region of a plant stem are of high quality, and are suitable for a wide range of applications. In an embodiment, there is provided an apparatus configured such that when a plant stem comprising a bast portion and a central core is passed through the first separation assembly, the bast portion is substantially removed such that substantially only the woody core is interactable with by the second drive assembly. Configuring the apparatus in this manner ensures that the extraction process can operate at a high efficiency, allowing for the extraction of a large amount of high quality bast fibres from a plant stem feedstock. In an embodiment, there is provided an apparatus wherein the plant feedstock is a fibrous plant leaf. The apparatus's ability to handle fibrous plant leaves extends its utility to a wider range of plant materials, making it versatile and adaptable. According to a second aspect of the disclosure, there is provided a method of extracting one or more elementary fibres from a plant feedstock using an apparatus according to the first aspect. The extraction method allows for the production of high quality elementary fibres suitable for a wide range of applications, from a variety of plant feedstocks. According to a third aspect of the disclosure, there is provided an elementary fibre produced using an apparatus according to the first aspect, and / or a method according to the second aspect. Fibres produced using the disclosed apparatus, and / or using the disclosed method, are of high quality and are suitable for a wide range of applications. Brief description of the drawings Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 illustrates an apparatus according to the present disclosure. Detailed description An apparatus according to the present disclosure is configured to extract elementary fibres from plant source material. More specifically, the apparatus is configured to extract elementary fibres from plant stems and from plant leaves, as discussed in more detail below. The term "elementary fibre" according to the present disclosure refers to a single plant fibre. In examples where the one or more elementary fibres are extracted from a plant stem, an elementary fibre may be a single phloem or a section thereof. In examples where the elementary fibres are extracted from a plant leaf, an elementary fibre may be a single phloem or section thereof, a single xylem or section thereof, or a combination of both. In some examples, the term "elementary fibre" may additionally or alternatively be referred to as one or more of a "phloem", "phloem fibre", "xylem", "skin fibre", "leaf fibre", "bast fibre", or "plant fibre". A wide range of plants and plant crops contain fibres that are of interest for extracting. Many of these plants may be categorised as either "dicotyledon" ("dicots") or "monocotyledon" ("monocots"). Dicots typically have fibrous stems, from which elementary fibres may be extracted. In dicot-type plants, the elementary fibres are extracted from the bast region of the plant stem. Monocots typically have fibrous leaves, from which elementary fibres may be extracted. In monocot-type plants, the elementary fibres are extracted from the fibrous portions of the leaves. In either plant type, elementary fibres may be bundled together in "fibrous bundles". In some examples, as explained in more detail below, these elementary fibre-containing bundles may be extracted by the apparatus, with further processing steps used to separate the bundles into individual elementary fibres. Extracted elementary fibres and / or elementary fibre bundles may be referred to as such, or may simply be referred to as "fibres". An apparatus according to the present disclosure may also be used to extract fibres from an extremely wide range of plant feedstocks. In particular, the apparatus is able to extract fibres from dry, rehydrated, fresh, and / or pre-treated plant feedstock. Furthermore, the apparatus is able to extract fibres from softer and less durable plant feedstocks, such as potato plant stems, that cannot be processed using existing options, such as decorticators. For simplicity, the remainder of this disclosure will primarily focus on an apparatus configured for use with extracting elementary fibres from the bast region of a plant stem, the plant stem being provided from a dicot plant. However, it should be understood that any such apparatus may also be used to extract fibres from other types of plant feedstock including, but not limited to, monocot plant leaves. An apparatus according to the present invention facilitates the efficient extraction of high quality fibres from plant feedstock. The properties of the fibres produced using the disclosed apparatus, and / or according to the disclosed method, make them suitable for use in a wide range of applications. Fibres extracted using the disclosed apparatus and method may be suitable for processing into apparel textiles and, in particular, for woven and knit apparel. The fibres may, in some example, be processable using equipment already widely used to process textile fibres, without significant (or, indeed, any) modification of the equipment. The properties of the fibres produced may also make them suitable for use in a wide range of further applications, including applications where they may not be woven into fabrics. Further possible applications may be: fibre reinforcement in fibre reinforced composite materials, face masks, insulation material, upholstery (including beds and bedding), and construction materials. Figure 1 illustrates an example of an apparatus (100) according to the present disclosure. The apparatus (100) comprises a first drive assembly (101) configured to move a plant feedstock, such as a plant stem (200), through the apparatus (100). In the illustrated example, the plant feedstock is a dicot plant stem (200) although, as discussed above, other plant feedstocks may be used. In the illustrated example, the first drive assembly (101) comprises a pair of rollers configured to grip the plant stem (200). The rollers are configured to rotate in opposite directions, thereby to move the plant stem (200) through the apparatus (100) (in a downward direction, in the example illustrated in figure 1, although any apparatus (100) orientation may be used). In some examples, the first drive assembly (101) may comprise alternative components configured to facilitate movement of the plant stem (200) through the apparatus (100). In the illustrated example, the rollers of the first drive assembly (101) do not comprise additional features to facilitate gripping and moving the plant stem (200). However, in some examples the rollers may comprise additional features such as a plurality of ridges and / or spikes, configured to assist with firmly gripping the plant stem (200). The apparatus (100) comprises a second drive assembly (102), which is also configured to move a plant stem (200) through the apparatus (100). In the illustrated example, the second drive assembly (102) also comprises a pair of rollers configured to grip the plant stem (200). The rollers of the second drive assembly (102) are configured to work in much the same way as those of the first drive assembly (101). In the illustrated example, the rollers of the second drive assembly (102) each comprise a plurality of ridges arranged around each respective surface of the rollers. These ridges are arranged so as to facilitate gripping the plant stem (200), thereby to assist with moving the plant stem (200) through the apparatus (100). As with the rollers of the first drive assembly (101), such an arrangement of surface features is merely one possibility that is contemplated. In the illustrated example, the ridges disposed on the surface of the rollers of the second drive assembly (102) may be particularly beneficial in providing a secure grip on the plant stem (200). This is because the plant stem (200) may be more difficult to grip securely after passing through the first separation assembly (103) given that, as discussed in more detail below, a substantial portion of the plant stem (200) may have been removed. The apparatus (100) further comprises a first separation assembly (103), disposed between the first drive assembly (101) and the second drive assembly (102). The first separation assembly (103) is configured to apply a separating force to the plant stem (200), thereby to remove at least a portion of the fibre-containing portion of the plant stem (200). In examples where the plant stem (200) is from a dicot-type plant, the first separation assembly (103) is configured to separate at least a portion of the bast region from the plant stem (200). As discussed above, in dicot-type plants, the bast region is the portion of the plant stem (200) containing the elementary fibres to be extracted. The first drive assembly (101) may be arranged so as to push the plant stem (200) into, and at least partially through, the first separation assembly (103). The second drive assembly (102) may be arranged so as to at least partially pull the plant stem (200) through the first separation assembly (103). In some examples, the first and second drive assemblies (101, 102) may be arranged such that when the plant stem (200) is passing through the first separation assembly (103), the plant stem (200) is always being acted on by at least one of the first and second drive assemblies (101, 102). In the illustrated example, the first separation assembly (103) comprises a pair of rollers configured to apply a separating force to the plant stem (200) as it is moved through the apparatus (100). In one example, the separating force may be applied by the rollers rotating in a direction opposite to that of the direction of motion of the plant stem (200) through the apparatus (100). In other examples, the rollers of the separation assembly may rotate in the same direction as the motion of the plant stem (200) through the apparatus (100), but at a speed that is different from that of the plant stem (200). Such a speed differential would have the effect of applying a separation force to the surface of the plant stem (200) as it is moved through the first separation assembly (103). In some examples, the separation force may be applied in a direction that is substantially opposite to the direction that the plant stem (200) is moving through the apparatus (100). In such examples, the separation force may be applied by a portion of the separation assembly (such as one or more rollers) moving in the opposite direction to the direction of motion of the plant stem (200). In other examples, the separation force may be applied by a portion of the separation assembly that is stationary, or even moving in the same direction as the plant stem (200) but at a lower speed. In either of these situations, when the plant stem (200) is moving through the apparatus (100), the portion of the separation assembly will have a relative motion in substantially the opposite direction to that of the plant stem (200). The separation assembly will thereby apply a separation force to the plant stem (200) in substantially the opposite direction to the motion of the plant stem (200) through the apparatus (100). In the illustrated example, the rollers of the first separation assembly (103) each comprise a plurality of ridges. These ridges are configured to assist with gripping and separating from the plant stem (200) the fibre containing portions. In other examples, the rollers of the first separation assembly (103) may additionally, or alternatively, comprise other means for assisting with the extraction of the fibres. For example, the rollers may each comprise a plurality of spikes and / or sharp edges. In some examples, the first separation assembly (103) may comprise alternative means for applying a separation force to the plant stem (200). In some examples, the first separation assembly (103) may comprise one or more sharp edged members (such as blades, not shown in the illustrated example) arranged to split, slice and / or shear the fibre containing portions from the plant stem (200). These features may be in addition to, or instead of, the rollers shown in the illustrated example. In the illustrated example, the first separation assembly (103) comprises a pair of rollers that are substantially aligned with the first drive assembly (101). The rollers are configured such that, in use, they rotate in a direction opposite to that of the corresponding rollers in the first drive assembly (101), thereby to impart a separation force on the plant stem (200). Such an arrangement may be beneficial, for example by simplifying the construction and operation of the apparatus (100). In other examples where the first separation assembly (103) comprises a pair of rollers, said rollers may be arranged in an orientation different to that of the corresponding rollers in the first drive assembly (101). Any relative orientation may be used, for example the rollers of the first separation assembly (103) may be arranged in a direction perpendicular to that of the rollers of the first drive assembly (101), with the respective rotational axes of the first separation rollers being parallel with the direction of motion of the plant stem (200). In such an example, if the apparatus (100) is arranged substantially vertically (as shown in figure 1), with the first drive assembly (101) rollers arranged substantially horizontally, the rollers of the first separation assembly (103) would be arranged substantially vertically. In such an orientation, the rollers of the first separation assembly (103) could apply the separation force in a direction that is substantially perpendicular to the direction of movement of the plant stem (200) through the apparatus (100). In another example, the rollers of the first separation assembly (103) may be arranged such that the rotational axes of the first separation assembly rollers and the first drive assembly rollers form an offset angle of up to 90 degrees. In some examples, an offset angle of less than 60 degrees may be beneficial. In some examples, an offset angle of around 10 degrees may be particularly beneficial. In such arrangements, the separation force applied by the first separation assembly (103) may be, at least in part, a shear force. Such an arrangement may be beneficial in extracting fibres from a particular kind of plant feedstock. Furthermore, such arrangements may assist with the removal and capture of the extracted fibres, by directing the extracted fibres away from the plant stem. Such an arrangement may also be particularly beneficial in conjunction with a second separation assembly arranged in a different orientation, as discussed in more detail below. Figure 1 illustrates a first removal assembly (104), configured to remove fibres from the separation assembly after being separated from the plant stem (200). In the illustrated example, the first removal assembly (104) comprises a pair of rollers each comprising brushes (105). The brushes (105) of the first removal assembly (104) are arranged such that, in use, they make contact with the separation assembly thereby to help remove from the separation assembly the extracted fibres. In the illustrated example, the brushes (105) are rotatable, thereby improving the efficiency with which they are able to remove the extracted fibres from the separation assembly. In examples where the first separation assembly (103) comprises a pair of rotatable rollers, and where the first removal assembly (104) comprises a pair of rotatable brushes (105), the brushes (105) of the first removal assembly (104) may be configured to each rotate either in a direction opposite to that of the separation roller with which they make contact, or in the same direction as the respective separation roller but at a different tangential speed. In some examples, the rotational speed of the brushes (105) may be equal to, or faster than, the rotational speed of the respective rollers of the first separation assembly (103). This rotation may improve the efficiency with which the brushes (105) are able to remove the fibres from the rollers of the separation assembly. Although not shown in the illustrated example, the apparatus (100) may comprise means for collecting and retaining the extracted fibres. For example, one or more collection assemblies may be arranged to collect extracted plant fibres from the first separation assembly (103) and / or the first removal assembly (104). As discussed in more detail below, In some examples, the apparatus (100) may comprise second or further separation assemblies. In such examples, each respective separation assembly may comprise a corresponding removal assembly (104) and / or a corresponding collection assembly. Figure 1 illustrates a first guide assembly (106), configured to guide the plant stem (200) into the first separation assembly (103). In the illustrated example, the first guide assembly (106) comprises a pair of guide members arranged to direct an end of the plant stem (200) into the first separation assembly (103), This is merely an example of how the first guide assembly (106) may be arranged, and other arrangements are contemplated. Figure 1 illustrates a second guide assembly (107), configured to guide the plant stem (200) into the second drive assembly (102). In the illustrated example, the second guide assembly (107) comprises a pair of guide members arranged to direct an end of the plant stem (200) into the first separation assembly (103). This is merely an example of how the second guide assembly (107) may be arranged, and other arrangements are contemplated. Although the illustrated example shows two guide assemblies, it should be appreciated that this is merely an illustration of a possible arrangement of an apparatus according to the present disclosure. In some examples, further guide assemblies may be included, and in some examples there may be no guide assemblies present. In some examples, as discussed in more detail below, the apparatus (100) may comprise additional drive assemblies and / or separation assemblies. In such examples, each additional drive assembly and / or separation assembly may comprise a guide assembly configured to guide the plant stem (200) into the respective drive or separation assembly. In some examples, the apparatus (100) may comprise a second separation assembly. In such examples, the addition of a second separation assembly may help to improve the efficiency with which the apparatus (100) is able to extract fibres from plant feedstock. The second separation assembly may be arranged in any number of ways, however two particular arrangements are envisaged: 1. The second separation assembly is arranged to be substantially the same as the first separation assembly (103). In such an arrangement, the second separation assembly may help to improve the efficiency with which the fibres are extracted simply by repeating the process performed by the first separation assembly (103). 2. The second separation assembly is arranged in a different way to the first separation assembly (103). This may be comprising different components and / or by being aligned in a different orientation. In this arrangement, the second separation assembly helps to improve the efficiency with which fibres are extracted by extracting fibres that may not have been extractable by the orientation and / or configuration of the first separation assembly (103). Examples of the first arrangement should be relatively straightforward to understand, and so will not be discussed in particular detail. However, some particular examples of the second scenario are discussed in more detail below. In some examples, the first and second separation assemblies may comprise similar components (such as a pair of rollers) but may be aligned differently. In such examples, any respective alignment of the two separation assemblies may be used. In such examples, the different alignments of the first and second separation assemblies may allow the respective separation assemblies to extract fibres from different portions of the plant stem (200). For example, the first separation assembly (103) may not be able to extract fibres from all areas of the surface of the plant stem (200) equally. The second separation assembly may therefore be aligned specifically to target the portions of the plant stem (200) from which the first separation assembly (103) was not able to extract fibres. In some examples, the first and second separation assemblies may comprise different components, configured to apply a respective separation force differently. For example, the first separation assembly (103) may comprise one or more bladed members configured to remove fibre-containing sections of the plant feedstock by splitting and / or peeling the fibre-containing sections away from the plant stem (200). The second separation assembly could instead comprise a pair of rollers, configured to apply a separating force to the remaining fibre-containing sections of the plant stem (200). Such an arrangement may be beneficial for plant feedstocks that have particularly thick or tough fibre containing regions. In some examples, the second separation assembly may be positioned between the first separation assembly (103) and the second drive assembly (102), such that the plant stem (200) moves directly from the first separation assembly (103) into the second separation assembly. In other examples, the second separation assembly may be positioned after the second drive assembly (102) (the term "after" referring to the passage of the plant stem (200) through the apparatus (100), during use). In such examples, the apparatus (100) may comprise a third drive assembly arranged such that the second separation assembly is positioned between the second and third drive assemblies. The relative positioning of the second and third drive assemblies and the second separation assembly may be analogous to the relative positioning of the first and second drive assemblies (101, 102) and the first separation assembly (103). In each case, a drive assembly may be arranged to move the plant stem (200) into a separation assembly, and a further drive assembly arranged to move the plant stem (200) out of the separation assembly. In some examples, a third and fourth drive assembly may be positioned after the second drive assembly (102), with a second separation assembly disposed therebetween. In other examples, a second or subsequent apparatus (100) may be arranged to process the plant stems (200) after the plant stems (200) have passed through the first apparatus (100). By using additional apparatus (100), the efficiency of extracting fibres from the plant feedstock may be increased. In some examples, the second drive assembly (102) may be omitted. In such examples, the first drive assembly (101) may be configured to move the plant stem (200) substantially through the first separation assembly (103). In such examples, the first separation assembly (103) may be configured to release the plant stem (200) once it is no longer being moved by the first drive assembly (101), thereby to prevent the plant stem (200) from being retained within the separation assembly. In some examples, one or more of the drive assemblies may be configured to apply a crushing force to the plant stem (200). In an example where the first drive assembly (101) is configured in such a way, this may be beneficial in improving the efficiency with which the first separation assembly (103) is able to remove fibres from the plant stem (200). In an example where the first separation assembly (103) comprises a pair of rollers, the crushing force applied by the first drive assembly (101) will act to flatten the plant stem (200), thereby increasing the surface area of the plant stem (200) with which the rollers of the first separation assembly (103) is able to interact. In some examples where the apparatus (100) comprises a second separation assembly arranged after the second drive assembly (102), the second drive assembly (102) may be configured to apply a crushing force to the stems in a different direction to that of the first drive assembly (101). In such examples, this may help to improve the efficiency of the second separation assembly, by flattening the plant stem (200) in a different way, thereby exposing a different surface of the plant stem (200) to the second separation assembly. In some examples, where the apparatus (100) comprises a second separation assembly arranged after the second drive assembly (102), the second drive assembly (102) may be configured to alter the orientation of the plant stem (200), For example, the second drive assembly (102) may be configured to rotate the plant stem, thereby exposing a different surface of the plant stem (200) to the second separation assembly. In some examples, the apparatus (100) may further comprise an alignment assembly configured to align the plant stems (200) (or other plant feedstock) prior to entering the first drive assembly (101). Many different alignment mechanisms are known in the art, and any may be suitable for use in this application. By aligning the plant stems (200) prior to entering the first drive assembly (101), the efficiency with which the apparatus (100) functions may be improved. Furthermore, blockages caused by incorrectly aligned plant stems (200) may be reduced. As mentioned above, the apparatus (100) according to the present disclosure is able to extract fibres from a wide range of plant feedstocks, and from plant feedstocks in a wide range of conditions. For example, the apparatus may be used to extract fibres from a feedstock that comprises plant feedstock in any one or more of the following conditions: Dry: where the plant feedstock has been dried out to a low moisture content, for example of between 10% and 20%. Drying may be performed using any suitable method, such as: sun, heat, airflow, or chemicals. - Fresh: where the plant feedstock is still green, typically within a few days of being harvested. The moisture content of fresh plant feedstock is typically between 70% and 95%. - Rehydrated: Dry plant feedstock can be rehydrated using various methods, but typically involving soaking the plant feedstock in a rehydrating agent. In some examples, the method of rehydration may involve anything from submerging the plant feedstock for a few minutes to soaking overnight. The rehydration agent may be water, or may be a solute comprising a salt (such as NaCI). The moisture content of rehydrated plant feedstock can vary enormously, for example from 10% to 99% moisture. - Pre-processed: the feedstock may have undergone one or more pre-processing steps to at least partially break down the feedstock material. Examples of possible pre-processing method steps are described in more detail below. As noted above, the apparatus (100) according to the present disclosure is able to extract fibres from a plant feedstock without the need for pre-processing steps. However, in some examples, one or more pre-processing steps may be employed in order to further increase the efficiency of fibre extraction. Examples of possible preprocessing steps are detailed below. In some examples, the plant feedstock may be subjected to one or more preprocessing steps prior to undergoing fibre extraction. Examples of pre-processing steps include: - Crushing: the plant feedstock may be crushed in order to enable faster dehydration. In some examples, this may be done using harvesting machinery, in other examples a dedicated apparatus may be used. Crushing is typically performed prior to storing the plant feedstock, in order to facilitate dehydration. In some examples, crushing can reduce the dehydration time by as much as 50%. - Baling: the plant feedstock may be baled up. This can be beneficial in improving the ease and efficiency with which the feedstock can be stored ahead of fibre extraction. - Refrigeration: the plant feedstock may be stored at a lowered temperature, thereby to help preserve the plant feedstock in a fresh state before fibre extraction. In some examples, refrigeration can help prevent the formation of mould on the plant feedstock, which can be detrimental to the quality of the plant feedstock and thus to the produced fibre product. Other ways to prevent mould may alternatively, or additionally, be used including applying an airflow to the plant feedstock. - Defoliation: in examples where the plant feedstock is a plant stem, the plant stem may have any leaves stripped from it. - Cutting: in some examples, the plant feedstock may be cut or smashed as part of the harvesting process. - Ensiling: the plant feedstock may be fermented in an anaerobic environment in a similar process to agricultural silage. This may be advantageous for long term preservation without the need for substantial dehydration. In some examples, one or more pre-processing steps may be performed in order to at least partially break down the plant feedstock before fibres are extracted using the apparatus (100). In some examples, pre-processing may include one or more of: heat treatment, dehydration, crimping, exposure to electrical discharge, microwaving, steaming, boiling, blanching, steam explosion, chemical treatment, and ultrasound. Each of these different pre-processing steps may help to break down different portions of the feedstock material. In some examples, pre-processing may result in a decrease in the overall mass of the plant feedstock. The mass loss may be, for example, due to the breakdown of non-celluiosic material. This may reduce the bonding between the fibres in the plant feedstock material. In some examples, the non-ce!lulosic material may comprise hemicellulose. In examples where retting is performed (including enzymatic retting), pre-processing may allow for the retting agents (such as enzymes and / or chemicals) to more easily access pectin-containing portions of the plant feedstock. This in turn may improve the speed and / or efficiency of retting. In an example, heat treatment may involve heating the plant feedstock in a dry atmosphere, in order to break down hemicellulose material in the plant feedstock. In some examples, this may result in a mass loss of between 40% and 55% of the plant feedstock following pre-processing. In some examples, the plant feedstock may be heated to at least 260 degrees centigrade. In another example, boiling may involve immersing the plant feedstock in boiling water for a sufficient amount of time to cause breakdown of some of the non-cellulosic material. In an example, a boiling time of 225 minutes may result in a mass loss of approximately 40% of the plant feedstock following pre-processing. In another example, microwaving may involve subjecting the plant feedstock to microwave radiation. In an example, the plant feedstock may be soaked in water before being subjected to microwave radiation. Soaking the plant feedstock may help the microwave radiation to be absorbed by the plant feedstock, for example by increasing the water content of the plant feedstock. In an example, subjecting soaked plant feedstock to microwave radiation may result in a mass loss of between 20% and 40%. In a further example, crimping may involve physically crushing and / or hammering the plant feedstock. This may result in the breakdown of some of the non-cellulosic material in the plant feedstock. In some examples, the plant feedstock material is subjected to retting, in order to break down the bonding between the fibres and / or fibre bundles within the plant-feedstock, thereby to aid in the extraction of the fibres from the plant feedstock. In some examples, this may involve enzymatic retting, although other retting methods may alternatively, or additionally, be employed. In some examples, retting may involve enzymatic retting. This may be performed using a pectinolytic enzyme, which breaks down the pectin in order to allow the extraction of the fibres. In some examples, enzymatic retting involves applying the retting enzymes directly to the plant feedstock. In some examples, the enzymes may be suspended in a liquid and the liquid may be applied to the plant feedstock; this may involve spraying the liquid on to the plant feedstock, or at least partially submerging / immersing the plant feedstock in the liquid. In some examples, enzymes may additionally, or alternatively, be applied to the plant feedstock through the use of microorganisms. In some examples, the microorganisms may comprise bacteria and / or fungi. In such examples, enzyme generating bacteria and / or fungi may be applied to the plant feedstock; the bacteria and / or fungi then produce the retting enzymes in order for the enzymatic retting to take place. In such examples, the bacteria and / or fungi may be suspended in a liquid and the liquid may be applied to the plant feedstock; this may involve spraying the liquid on to the plant feedstock, or at least partially submerging the plant feedstock in the liquid. In some examples, a combination of retting enzymes and bacteria that produce retting enzymes may be used in the retting process. In some examples, retting may use an enzyme selected from a group comprising: pectinase, cellulase, laccase and hemicellulase. Each of these types of enzyme breaks down part of the bonding material that bonds the fibres within the plant feedstock. One or more of these enzymes may be used in order to help break down this bonding material. In some examples, one or more of these enzyme types may be used directly. In other examples, bacteria may be used to produce one or more of these enzyme types. In some examples, an enzyme used during retting may be selected from a group comprising: pectate lyase, pectinesterase (endo)polygalacturonase, protopectinase, exopolygalacturonase, polygalacturonase, laccase, xylanase, exo-cellulase, endocellulase, endogenous xylanase, exogenous xylanase, exoxylosidase, arabinfuranosidase, endogalactanase, exogalactosidase, exoglucanase, glucanase, lignin peroxidase, cellobiase, protease, mannanase, alpha-amylase, phytase, lysozyme, bromelain, keratinase, pectinase, mannanse, beta-glucosidase, trypsin, levansucrase and lipase. Each of these enzymes are known to be effective in breaking down part of the bonding material that bonds together fibres in the plant feedstock. In some examples, one of these enzymes may be used in isolation. In other examples, two or more enzymes may be used in combination. In some examples, an enzyme used during retting may be produced using a bacteria selected from a group comprising: Bacillus subtilis, Bacillus Paralichemformis, Dickeya chrysanthemi, Erwinia, Arthobacter, Pseodomonas, Streptomyces, Bacillus felsineus, Granulobacter pectinovorum, Bacillus asterosporous, Pythium ultimum, Bacillus macerans, Bacillus fiesineus, Bacillus polymyxa and Bacillus thuringiensis. Each of these bacteria have been shown to produce an enzyme known to be effective in breaking down part of the bonding material that bonds together fibres in the plant feedstock. In some examples, one of these bacteria may be used in isolation to produce enzymes for the enzymatic retting process. In other examples, two or more bacteria may be used in combination. In some examples, the bacteria may be applied directly to the plant feedstock. In other examples, the bacteria may first be used to produce enzymes and then subsequently the produced enzymes may be applied to the plant feedstock (without the presence of the bacteria). In some examples, an enzyme used during retting may be produced using a fungus selected from a group comprising: Penicillium glaucum, Penicillium italicum, Aspergillus nlger and Aspergillus oryzae. Each of these fungi have been shown to produce an enzyme known to be effective in breaking down part of the bonding material that bonds together fibres in the plant feedstock. In some examples, one of these fungi may be used in isolation to produce enzymes for the enzymatic retting process. In other examples, two or more fungi may be used in combination. In some examples, the fungi may be applied directly to the plant feedstock. In other examples, the fungi may first be used to produce enzymes and then subsequently the produced enzymes may be applied to the plant feedstock (without the presence of the bacteria). In some examples, the above-described enzymes, bacteria and fungi may be used in any combination in order to perform the enzymatic retting of the plant feedstock. In some examples, alternative retting methods may alternatively, or additionally, be used. Examples include water retting, dew retting, microbial retting, and chemical retting. Chemical retting involves the use of chemicals to assist with breaking down the bonding material within the plant feedstock, in order to allow the fibres to be extracted. In some examples, chemical retting may involve the use of one or more chemicals selected from a group comprising: hydrogen peroxide, sodium hydroxide, sodium chloride, ethylenediaminetetraacetic (EDTA), sodium bicarbonate, aminopolycarboxylic acids, glacial acetic acid, tartrine, chitosan, citric acid, alkylglucoside, potassium sulfate, sorbitol, glycerol, cysteine, sodium oxalate, bentonite, maleic anhydride, polyacrylic acid, polyhydroxyacrylic acid, sodium lauryl sulfate, sodium tripolyphosphate, tween 20, erythritol, hydroxypropionic acid, sodium citrate, potassium sorbate, attapulgite clay, magnesium sulfate, ethanol and calcium hydroxide. Each of these chemicals has been shown to assist in breaking down at least part of the bonding material of the plant feedstock. Water retting may involve immersing the plant feedstock in water for up to 2 weeks. In some examples, natural water sources such as a stream or a lake may be used. Dew retting may involve exposing the piant feedstock to naturally occurring dew for an extended period of time, for example for around a month. Ensiling retting may involve fermenting the plant feedstock in a contained anaerobic environment, such as a wrapped bale. Microbial retting may involve exposing the plant feedstock to a liquid suspension that also contains microorganisms. This may be achieved, for example, by immersing the plant feedstock in such a liquid suspension, or by spraying such a liquid suspension on to the plant feedstock. The microorganisms produce retting agents, which may include, for example, enzymes. Examples of such enzyme-producing microorganisms are discussed above in relation to enzymatic retting. After the fibres have been extracted from the plant feedstock using the apparatus (100), additional processing steps may be performed. Such processing steps may, for example, help to improve the quality of the extracted fibres. Some examples of such processing steps are outlined below. In some examples, refining of the fibres may be performed. Refining is a process in which fibre bundles are mechanically pulled into individual fibres and / or microbundles. Refining also allows for the removal of non-fibrous material, thereby improving the quality and purity of the fibres. Refining may involve the use of, for example, ultrasonication and / or carding. Ultrasonication is a process wherein ultrasonic waves (i.e., sound waves with a frequency of at least 20 kHz) are used to agitate fibres and / or fibrous bundles in order to help separate and align them. Carding is a mechanical process that disentangles (and in some examples, cleans and / or intermixes) fibres and / or fibrous bundles; this may be performed manually using hand tools or by a machine. In some examples, degumming may be performed to remove bonding material that may be retained between fibres and / or fibrous bundles. In some examples, such bonding material may comprise pectin and / or lignin. In some examples the bonding material may contain gums (which are largely made up of pectin, hemicellulose and lignin). In some examples, degumming may be performed in order to break down at least some of this bonding material. Degumming may involve, for example, enzymes, enzyme-producing bacteria, enzyme-producing fungi, chemicals, and / or mechanical force. Degumming may involve any of the enzymes, enzyme-producing bacteria, an enzyme-producing fungi described above in relation to enzymatic retting. In some examples, degumming may additionally, or alternatively, involve the use of chemicals to break down at least some of the remaining bonding material. Chemicals for use in degumming may be selected from a group comprising: hydrogen peroxide, sodium hydroxide, sodium chloride, ethylenediaminetetraacetic (EDTA), sodium bicarbonate, aminopolycarboxylic acids, glacial acetic acid, tartrine, chitosan, citric acid, alkylglucoside, potassium sulfate, sorbitol, glycerol, cysteine, sodium oxalate, bentonite, maleic anhydride, polyacrylic acid, polyhydroxyacrylic acid, sodium lauryl sulfate, sodium tripolyphosphate, tween 20, erythritol, hydroxypropionic acid, sodium citrate, potassium sorbate, attapulgite clay, magnesium sulfate, ethanol and calcium hydroxide. In some examples of degumming, fibrous bundles are hydrolysed enzymatically to break down the "gums" (pectins, lignins, hemicelluloses, etc.,.). The goal of degumming is to release fibres from each other and obtain cleaner fibres. In some examples, degumming may involve one or more of: using a pectinase solution to breakdown the gums; using mechanical pre-treatment; using mechanical pre-treatment with microwaves and / or ultrasound, optionally in the enzymatic solution; and using chemical chelators such as EDTA, oxalic acid and turmeric. In some examples, after extraction of the fibres using the apparatus (100), any of the above described processing steps may be repeated any number of times, in order to further separate and refine the fibres. In some examples, an apparatus (100) according to the present disclosure may be at least partially incorporated into another apparatus. In some examples, the apparatus (100) may be incorporated into a harvesting machine, thereby allowing for the immediate extraction of fibres from harvested plant feedstock. Examples of advantages of incorporating the apparatus (100) in this manner are: - Avoiding the need for long term storage, and / or the need to transport the plant feedstock to another location after harvesting for fibre extraction. - Reducing the cost of harvesting plant feedstock for use with the apparatus (100), by incorporating the process of harvesting plant feedstock with the process of harvesting the rest of the crop. - Extracting the fibres immediately allows for the fibres to be dried for further processing, rather than drying the plant feedstock before extraction, thereby increasing the efficiency and reducing the cost of fibre production. - Extracting the fibres immediately allows for any plant feedstock waste to be 5 immediately returned to the field (or other location) where the plant feedstock is harvested, thereby reducing the impact of nutrient removal from the land. Incorporating an apparatus (100) into a harvesting machine may thus allow for improved process efficiency when extracting fibres from a plant feedstock. io Although the invention has been described in considerable detail in language specific to structural features, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features described. Rather, the specific features are disclosed as exemplary preferred forms of implementing the claimed 15 invention. Stated otherwise, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. Therefore, while exemplary illustrative embodiments of the invention have been described, numerous variations and alternative embodiments will occur to those skilled in the art. Such variations and 20 alternate embodiments are contemplated, and can be made without departing from the spirit and scope of the invention.

Claims

1. An apparatus for extracting one or more elementary fibres from a plant feedstock, the apparatus comprising:a first drive assembly;a second drive assembly; anda first separation assembly disposed between the first and second drive assemblies;the first and second drive assemblies each being configured to move the plant feedstock through the apparatus; andthe first separation assembly being configured to apply a separating force to the plant feedstock in order to extract one or more elementary fibres.

2. An apparatus according to claim 1, wherein the first drive assembly comprises a pair of rollers configured to grip the plant feedstock, thereby to move the plant-feedstock through the apparatus.

3. An apparatus according to claims 1 or 2, wherein the first drive assembly is configured to facilitate movement of the plant feedstock into and at least partially through the first separation assembly.

4. An apparatus according to any preceding claim, wherein the second drive assembly comprises a pair of rollers configured to grip the plant feedstock, thereby to move the plant feedstock through the apparatus.

5. An apparatus according to any preceding claim, wherein the second drive assembly is configured to facilitate movement of the plant feedstock out of the first separation assembly.

6. An apparatus according to any preceding claim, wherein the first separation assembly is configured to apply a separation force in a direction substantially opposite to the direction of motion of the plant feedstock through the apparatus.

7. An apparatus according to any preceding claim, wherein the first separation assembly comprises a pair of rollers.

8. An apparatus according to claim 7, wherein the rollers of the first separation assembly are configured to be rotatable in order to apply a separation force to theplant feedstock in substantially the opposite direction to the motion of the plant feedstock through the apparatus.

9. An apparatus according to any preceding claim, wherein the first separation assembly is configured to apply a shearing force to the plant feedstock.

10. An apparatus according to any preceding claim, wherein the first separation assembly is configured to apply a splitting and / or peeling force to the plant feedstock.

11. An apparatus according to any preceding claim, further comprising a removal assembly configured to remove the one or more separated elementary fibres from the first separation assembly.

12. An apparatus according to claim 11, wherein the removal assembly comprises one or more brushes.

13. An apparatus according to claims 11 or 12, wherein the removal assembly comprises one or more rotatable brushes.

14. An apparatus according to any preceding claim, wherein the first drive assembly is configurable to apply a crushing force to the plant feedstock.

15. An apparatus according to any preceding claim, further comprising one or more guide assemblies configured to, in use, guide the plant feedstock through the apparatus.

16. An apparatus according to claim 15, comprising a first guide assembly positioned between the first drive assembly and the first separation assembly, the first guide assembly being configured to, in use, guide the plant feedstock into the first separation assembly.

17. An apparatus according to claims 15 or 16, comprising a second guide assembly disposed between the first separation assembly and the second drive assembly, the second guide assembly being configured to, in use, guide the plant feedstock into the second drive assembly.

18. An apparatus according to any preceding claim, further comprising a second separation assembly.

19. An apparatus according to claim 18, wherein the second separation assembly is disposed between the first separation assembly and the second drive assembly.5 20. An apparatus according to claim 18, further comprising a third drive assembly,wherein the second separation assembly is disposed between the second drive assembly and the third drive assembly.

21. An apparatus according to any preceding claim, wherein:io the plant feedstock is a plant stem comprising a bast region; andthe one or more elementary fibres are extracted from the bast region of the plant stem.

22. An apparatus according to claim 21, wherein the apparatus is configured such that when a plant stem comprising a bast portion and a central core is passed through 15 the first separation assembly, the bast portion is substantially removed such that substantially only the woody core is interactable with by the second drive assembly.

23. An apparatus according to any of claims 1 to 20, wherein the plant feedstock is a fibrous plant leaf.2024. A method of extracting one or more elementary fibres from a plant feedstock using an apparatus according to any preceding claim.

25. An elementary fibre produced using an apparatus according to any of claims 1 25 to 23 and / or a method according to claim 24.

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