HOMOGENISER IMPACT HEAD

FIELD

[001] The field is related to homogenisers, and more particularly to homogenisers for the manufacturing of atomic scale laminar materials such as graphene.

BACKGROUND

[002] Graphene is a two-dimensional allotrope of carbon, consisting of sheets of a few atoms thickness in a hexagonal structure. Graphite, the widely used mineral is effectively a crystalline form of graphene, in which layers of graphene are bound together by van der Waals forces. Graphene has attracted considerable interest since its discovery as an isolatable material in 2004. The novel mechanical, thermal and electrical properties of the material suggest a number of uses. Graphene can be produced on a laboratory scale sufficient for experimental analysis, but production in commercial quantities is still a developing area. Other single layered structures such as boron nitride are expected to exhibit similarly interesting properties in the nanotechnology field.

[003] A review of this technology has been compiled by Min Yi and Zhigang Shen and their titled ‘A review on mechanical exfoliation for the scalable production of graphene’, Journal of Materials Chemistry, A, 2015, 3, 11700 provides an overview of the state of the art regarding graphene production. Bottom-up techniques, such as chemical vapor deposition and epitaxial growth, can yield high-quality graphene with a small number of defects. The resultant graphene is a good candidate for electronic devices. However, these thin-film growth techniques suffer from a limited scale and complex and hence expensive production and cannot meet the requirements of producing industrially relevant quantities of graphene.

[004] Large-scale production of graphene at a low cost has been demonstrated using top- down techniques, whereby graphene is produced through the direct exfoliation of graphite, sometimes suspended in a liquid phase. The starting material for this is three-dimensional graphite, which is separated by mechanical and/or chemical means to reveal graphene sheets a few atoms thick.

[005] The original technique used by the discoverers of graphene, the “Scotch Tape” method can be used to prepare high-quality and large-area graphene flakes. This technique uses adhesive tape to pull successive layers from a sample of graphite. Based on the graphene samples prepared by this method, many outstanding properties of graphene have been discovered. However, this method is extremely labor-intensive and time consuming. It is limited to laboratory research and seems unfeasible to scale up for industrial production.

[006] The three-roll mill technique is a method to scale up the Scotch Tape method, using polyvinyl chloride (PVC) dissolved in dioctylphthalate (DOP) as the adhesive on moving rolls which can provide continuous exfoliation. Though the three-roll mill machine is a known industrial technique, the complete removal of residual PVC and DOP to obtain graphene is not easy and brings about additional complexity.

[007] Prof. Jonathan Coleman's group at Trinity College Dublin have developed a high-yield production of graphene by the sonication assisted liquid-phase exfoliation of graphite in 2008. Starting with graphite powder dispersed in specific organic solvents, followed by sonication and centrifugation, they obtained a graphene dispersion. This method of producing graphene is capable of scaling up but one shortcoming is the extremely low graphene concentration (around 0.01 mg/mL) of the suspension produced, which is not necessarily suitable for bulk production.

[008] Additionally, ultrasonic processors can only achieve the high-power density required in small volumes, so it is difficult to scale up this process to achieve any economy of scale. A relevant disclosure can be found in W02013/010211A1.

[009] Another technique that can produce a high yield while not being as labor intensive, or energy consuming, as the methods describe above, would be the use of shear force techniques. As is well known, graphite layers have a low resistance to shear force which makes graphite a useful lubricant. This has been exploited in a number of techniques which apply shear force to exfoliate graphene from graphite.

[010] Ball milling, a common technique in the powder industry, is a method of generating shear force. A secondary effect is the collisions or vertical impacts by the balls during rolling actions which can fragment graphene flakes into smaller ones, and sometimes even destroy the crystalline nature of structures.

[011] Several improvements to the ball milling technique have been attempted, such as wet ball milling with the addition of solvents, but these techniques still require a very long processing time (around 30 hours) and produce a high number of defects even if suitable for industrial scale, bulk, production. A relevant disclosure can be found in WO 2012117251 A1 . [012] Some shear force production techniques have used an ion intercalation step prior to applying the shear force to weaken the inter-layer bonds. This reduces the energy required to exfoliate the graphite into graphene, but the resulting graphene may be contaminated with residual ions contaminating the finished product, and the process requires additional time and cost which reduces the industrial application of this technique.

[013] More recently fluid dynamics-based methods have emerged for graphite exfoliation. These are based on mixing graphite in a powder or flake form with a fluid to form a suspension, the fluid can then be subjected to turbulent or viscous forces which apply shear stress to the suspended particles. Usually, the fluid is either a liquid of the type often used as a solvent and may include a surfactant mixture tailored to the removable from the finished product.

[014] One method of generating the shear forces is with a high shear, for example rotary mixer. Graphene exfoliation has been demonstrated using a kitchen blender to create shear forces on graphite particles in suspension. This process has been scaled up using commercial high shear mixers comprising rotating blades passing in close proximity to an aperture screen to produce high shear. The graphite particles experience a shear force applied by the fluid due to the difference in velocity of the mixing blades and the static shear screen. A relevant disclosure can be found in WO2012/028724A1 and WO 2014/140324 A1.

[015] A further method is the use of a high-pressure homogeniser with a micro fluidizer. The micro fluidizer in this case consists of a channel with a microscale dimension, meaning of around 75pm. Fluid is forced through the channel from an inlet to an outlet using high pressure. Because of the narrow dimension of the channel, there is a high shear force generated by viscous friction between the walls and the book flow which leads to delamination of the graphite. This method requires very high pressures and the starting graphite must already have been comminuted into the micron size range. A relevant disclosure can be found in WO2015/099457.

[016] There exists a need for a graphene production process that can produce graphene using less energy, that can be scaled up to high rates of production without loss of quality of the finished product. Such a process using a preprepared graphite solution, and a homogeniser valve is disclosed within WO 2021/198794, which discloses using areas of high and low pressure within the valve to apply force to the solution, which in turn can break down the graphite in the solution other useful products such as graphene. [017] Another method using such a homogeniser, for produce graphene, can be found in WO2018/069722, which discloses an apparatus wherein a pump is used to pump a graphite solution through a fluid conduit, at the end of the conduit the fluid flow is targeted towards the center of a symmetrical impact head, to provide the shear force, wherein the impact head is symmetrical around the axis parallel to the fluid flow. Wherein the impact head can be rotated around the axis of symmetry, so as to reduce the risk of localized wear around the area of impact, thereby extending the operational life-span of the impact head.

[018] Further in this apparatus the impact head may be attached to an adjustable member, so that the position of the impact head by be adjusted to along its longitudinal axis, thereby changing the size of the gap between the conduit and the impact head. In these cases, the gap size is adjusted to clear any blockages that form between the conduit and the impact head. The impact head may be attached to a pressure drop valve. Wherein the valve is used to provide a predetermined amount of backpressure from the conduit and other components, to improve the efficiency of the homogeniser.

[019] The impact head can be made of a hardened material, or at least the surface upon which the fluid impacts are covered in a layer of such a material. These hardened materials can be chosen so as to reduce the risk of wear to the impact head’s surface, and possible to increase the amount of shear force between the fluid and the impact head. Suitable materials that could be used include material(s) selected from the group tungsten carbide, zirconia, silicon nitride, alumina, silicon carbide, cubic or wurtzite boron nitride and diamond.

[020] The apparatus may also include an impact head surround, positioned around the impact head, or the outlet of the fluid conduit, which extends the region in which the fluid is constrained before exiting the apparatus, to try and further homogenize the fluid solution as it exits the apparatus, thereby improving the apparatus’ efficiently and yield.

[021] Such an apparatus is disclosed in UK patent application GB15181.5. That apparatus provides a fluid conduit for impacting a suspension of particles to be de-laminated against an impact head having an impact face and an annular gap. In practice it has been found that the apparatus has a limited lifespan before maintenance is required as the annular gap can either become clogged with particulate material and/or become worn so as to provide an uneven gap through which suspension preferentially flows and, which results in the gap becoming larger, reducing the homogenisers effect as the fluid pressure drops within the apparatus. Such clogging tends to occur when fresh portions of the impact head, or the surrounding annular surface are exposed, as the reduced homogenization due to the wear may leave larger particles in the solution, as well as the particles of debris from the worn areas.

[022] The present invention seeks to overcome the problems in previous techniques to provide a production method for graphene that is rapid, scalable to industrial quantities and energy efficient, via the above-mentioned homogeniser method. This application addresses the question of wear to the homogeniser impact head. The invention looks to provide an impact head which can reduce the amount of wear caused by regular use, while not reducing the effectiveness of the homogeniser’s shear force technique. This application also addresses the question of increasing the yield of a conventional impact head, and the problem of clogging, while not reducing the effectiveness of the homogeniser’s shear force technique.

[023] It should also be noted that such homogenisers may also be utilized in the production of a range of products, such a milk, alcohols, paint and medical solutions, as well as producing different nano structures such as the aforementioned graphene in the form of platelet stacks. However, each of these different products may require different parameters to be produced. Further, the nano structures may require specific parameters to produce the desired structure, for example when producing graphene nano platelets (GNP) they form into stacks of various size, the homogeniser may require different setting to produce stacks at a specific height. However, the above-mentioned homogenisers appear to only measure the initial pressure of the reactants before it enters the homogeniser. Therefore, there is a need to provide homogenisers, with a means on monitoring and adjust parameters to meet the specific requirements of different reactants. Such homogenisers may also require a means of monitoring the product produced by the homogeniser, to ensure such products meet the user’s requirements. In particular as high pressures and turbulent flow through a complex geometry are involved there is a need for an adaptive system to enable the highly nonlinear and dynamic systems behaviour to be both monitored and adapted to provide improved process control.

SUMMARY

[024]

BRIEF DESCRIPTION OF THE FIGURES

[025] Figure 1 depicts an impact head that utilizes a spherical rotating impact head, according to an embodiment of the present description; [026] Figure 2 depicts an impact head that utilizes an elliptical rotating impact head, according to an embodiment of the present description;

[027] Figure 3 depicts a cylindrical impact head, according to an embodiment of the present description;

[028] Figure 4 depicts a rotating impact head with a cowl, according to an embodiment of the present description;

[029] Figure 5 depicts an impact head that utilizes a plurality of embedded rotating impact heads, according to an embodiment of the present description;

[030] Figure 6 depicts an impact head that utilizes a ziggurat shaped stepped impact head, according to an embodiment of the present description;

[031] Figure 7 depicts a stepped impact head utilizing embedded rotating impact head in the center of the flat impact heads, according to an embodiment of the present description;

[032] Figure 8 depicts a stepped impact head utilizing embedded rotating impact head in the edges of the flat impact heads, according to an embodiment of the present description;

[033] Figure 9 depicts a flat impact head with pneumatic adjustments mechanism, according to an embodiment of the present description;

[034] Figure 10 depicts a sloped impact head with pneumatic adjustments mechanism, according to an embodiment of the present description;

[035] Figure 11 depicts a flat impact head, with a sloped housing and pneumatic adjustments mechanism, according to an embodiment of the present description;

[036] Figure 12 depicts a sloped impact head, with a sloped housing and pneumatic adjustments mechanism, according to an embodiment of the present description;

[037] Figure 13A depicts a frustro-conical impact head within a sloped housing, wherein the slope of the walls and the impact head are parallel, according to an embodiment of the present description; [038] Figure 13B depicts a frustro-conical impact head within a sloped housing, wherein the slope of the walls and the impact head are not parallel, according to an embodiment of the present description;

[039] Figure 14 depicts a conical impact head with a domed tip/point, with a sloped housing, according to an embodiment of the present description;

[040] Figure 15 depicts an impact head with a frustro-pyramidal geometry, according to an embodiment of the present description; and

[041] Figure 16 depicts a homogeniser system controlled by a control system, according to an embodiment of the present description.

DETAILED DESCRIPTION

[042] The present description provides an impact head designed for a homogeniser, in particular a homogeniser that uses shear force on a mixture of suspended graphite to form graphene. In the homogeniser, the mixture is injected into the apparatus at a relatively high pressure/flow rate, that then impacts upon the impact head, using the shear force of this collision to separate the graphite molecules to form graphene.

[043] In this process the continuous use of the apparatus may eventually cause wear to the impact head, such wear can lead to the impact head deforming and becoming less effective, and eventually the wear reaches a point where the impact head must be replaced. In some embodiments, homogeniser the impact head may be configured to rotate to reduce wear. In some embodiments, the impact head may rotate periodically, that is that when the flow has caused localized wear on the impact head, the deformation around these localized wear points may result in the force of the flow being uneven that results in the impact head rotating, resulting in an unworn portion of the impact head being exposed to the flow. Other impact heads may be configured to rotate the impact head continuously so as to reduce the overall wear by spreading the force across the entire impact head. In these devises the impact head is usually flat, or conical, to provide a relatively flat surface to maximize the generated shear force. However, by maximizing the shear force these designs also increase the risk of wearing the impact head.

[044] In contrast, in some embodiments, the present description provides an impact head with certain geometries, such as a spherical impact head, said impact head may be configured to be rotated by the impacts head mounting, or be free to rotate under the force of the flow. In particular the spherical impact head comprises a ball bearing, set inside a hemispherical cowl, wherein there is a small channel between the ball bearing and the cowl so that the ball bearing can rotate within the cowl, and that any of the fluid that flows pass the ball bearing is stopped by the cowl, after which it can follow the channel and return to the flow. Wherein the flow impacts the ball bearing creating shear force on the fluid by the impact, it is also noted that the fluid may experience additional shear force when flowing thought the channel between the ball bearing and the hemispherical cowl.

[045] In other embodiments, the cowl or impact head mounting may be configured to continuously rotate the ball bearing. In this case the rotation of the ball bearing may help reduce the amount of friction/shear force acting on the ball bearing, due to the rolling friction of the ball bearing, while also spreading the impact force over the surface of the ball bearing. By doing this the overall amount of wear on the ball bearing can be reduced, as instead of localized wear point the wear may be spread over the rotating surface.

[046] By utilizing either method above, the ball bearing impact head can be used to reduce the amount of wear on the impact head. However, it is noted that in the continuous rotation method, the rolling friction on the moving ball bearing would reduce the force on the ball bearing, but may also reduce the friction on the fluid particles in the flow, which in turn would reduce the effectiveness of the homogeniser. Another method which may help overcome this would be to pipe the fluid flow into the channel between the ball bearing and the cowl, that is to have the fluid impact the cowl with the rotating ball bearing adding additional frictional force as the fluid flows through the channel to improve the homogenization, compared to having the fluid impact a flat surface.

[047] Therefore, there is a need to provide to provide an impact head with a geometry that can allow some rotation, to reduce the overall wear on said head and to expose different portions of the impact head to the fluid flow, while also not have so much rotation that the impact heads rotation would reduce the shear force/friction on the fluid flow, as a lower shear force would decrease the graphene yield. With these criteria, several impact head alternatives are considered:

[048] In some embodiments, a spherical impact head mounted within a housing that allows said impact head to rotate is provided. When using this impact head, the rolling of the spherical impact head may reduce the force applied to the impact head itself reducing the overall wear. When used frequently the force of the fluid flow may result in localized wear at/near the point of impact, on the impact head, when this occurs the worn areas may experience an uneven force which in turn may force the impact head to rotate. This induced rotation may then result in the impact moving so that an unworn portion of the impact head replaces the worn area, by exposing a new unworn portion of the impact head to the fluid flow. In doing this the lifetime of the impact head can be extended as the rotations would limit the amount of localized wear, spreading the wear over the surface of the impact head.

[049] In some scenarios of this embodiment, the hosing may be configured to mechanically rotate the impact head, this is to say the housing can be configured to rotate the impact head by a certain angle, after a predetermined amount of time, and in some cases, thereby reducing the amount of localized wear as described above. But also, the housing may be configured to continuously rotate the impact head. The continuous rotation of the impact head may reduce the overall wear, as the rotational friction acting on the rotating surface have less force than the shear/friction force on a stationary surface. However, by using the rotational motion to reduce the force felt by the impact head, it may be possible that the same motion may reduce the force acting on the fluid, within the fluid flow. If so, the reduced force may affect the overall yield of the homogeniser. This may be counteracted by adding features to the surface of the continuously rotating impact head, such as grooves, ridges, flaps or sawtooth shaped teeth, these surface features can provide additional surfaces to the impact head, preferable in the form of a flat surface, where these extra surfaces can provide additional shear force when the fluid comes into contact with the rotating impact head, in this case more force than that generated by a smooth, rotating spherical surface. As the additional shear force may help to improve the homogeniser’s yield.

[050] In some embodiments the spherical impact head may be replayed with a cylindrical or elliptical impact head. These other geometries may be used to restrict the impact head’s rotation, specifically by limiting the degrees of freedom in which the impact head may rotate, in the case of the aforementioned geometries both may be limited to rotating around their respective elongated axis, which may be position parallel, or perpendicular, to the direction of the fluid flow. In particular the elliptical impact head may be positioned with the elongated axis parallel to the fluid flow, while the cylindrical impact head may have the elongated axis perpendicular, so that the fluid flow impacted the curve surface. In doing this the reduction in force caused by the rotational motion of the impact head may be reduced, improving the yield when compared to a freely rotating spherical head. Like the spherical impact heads, the elliptical and cylindrical heads may further comprise surface features that may provide addition surface area and/or provide flat surfaces to increase the shear force generated when the fluid impacts the impact head. Not that in the case of the cylindrical impact head the smooth cylinder may be replace with an impact head with a shape similar to that of a drill bit, or screw thread, to provide additional shear force. It is noted that when the impact head includes these additional surface features it is preferable that the impact head is driven, that is to say periodically or continuously rotated mechanically around their elongated axis, so as to maximize the amount of shear force being generated by these additional surface features.

[051] In some embodiments, the rotating impact head, be it spherical, elliptical, cylindrical or another rounded shape, may be embedded within a larger flat impact head. That is to say that the rotating impact head in housed within the center of a larger flat, or sloped, impact head, while still being free to rotate. In some cases, the inlet for the fluid flow may have a diameter the is smaller than, or equal to, the diameter/size of the rotating impact head, so as to target most or all of the flow towards the rotating impact head, the surround flat impact head may then provide a means to direct the flow after the initial impact potentially to further impact heads/surface, to further improve the yield of the homogeniser.

[052] In some embodiments, the inlet for the fluid flow may have a diameter that is wider than the diameter/size of the rotating impact head. In this case only some of the flow is directed at the rotating impact head, with the rest being directed to the surrounding flat, or sloped, impact head. Such a flow may be preferable as it seeks to strike a balance between the potentially lower force impacts of the rotating head, which may have a lower yield but also produces less wear on the impact head, with the potentially higher shear force impacts produced by the flat surface of the surrounding impact head, which may produce a higher yield but would be more susceptible to wear. Therefore, by using both impact head simultaneously this impact head can have increased yield compared to the rotating head alone, while having a longer life span than the flat impact head alone.

[053] In other embodiments, the impact head may be designed to include a plurality of rotating impact heads, which may either be embedded within the surface of a larger flat impact head or be placed adjected to one another in order to form a relatively flat surface out of the rotating impact heads. This type of impact head may have a lower risk of wear when compared to the imbedded rotating impact head describe above, as more of the overall surface, if not all of it, is able to rotate and therefore reduce wear, while the relatively flat surface created by the plurality of impact heads improve the amount of friction/shear force being produced. It is noted that such an impact head may comprise a housing that is capable of rotating the whole impact head, and/or moving the whole impact head tangentially, so as to expose different rotating impact heads, from the plurality of rotating impact heads, to be the target of the fluid flow thereby spreading the wear between the different rotating impact heads.

[054] In some embodiments the rotating impact head may be surrounded by a cowl, wherein there is a small channel between the cowl and the rotating impact head. In these embodiments the fluid flow may be directed through the channel to impact the cowl, once in the channel the rotating head may rotate to generate more friction with the fluid in the channel, thereby improving the efficiency of the homogeniser. In some cases, the rotating impact head may include surface features such as ridges or saw-teeth to provide additional surface area, to increase the amount of friction generated, by allowing the rotating impact head to act as a water wheel forcing the fluid through the channel. In some of these cases the cowl itself may be able to rotate in order to reduce localize wear on the cowl at the inlet to the channel. It is also noted that in the embodiments with one or more rotating impact heads embedded into a larger flat, or sloped, impact head, there may be a channel around the rotating impact head as described above.

[055] Another way that the impact head may improve the yield of the homogeniser is to have the fluid flow undergo multiple impacts. This may be achieved by using an impact head design that has multiple impact surfaces. One example of such a geometry would be the use of a ziggurat, or stepped structure. In these structures, after the fluid flow hits the initial impact head, using a flat, or sloped impacted head, or any of the rotating impact head geometries described above, the fluid flow is then flows over the edge of the impact head, where it may be directed to one or more pipes, or channels, which may help increase the fluids pressure/velocity as it flows down towards a second impact head, on a layer below the initial impact head. This second impact may further brake down the graphite in the fluid solution, thereby improving the efficiency of the homogenization. Note that the structure may comprise one, or more, additional layers. Each layer can comprise a plurality of impact heads, wherein the fluid flow from the layer above is directed towards the layer below, specifically the fluid can flow through a pipe or channel to target the flow towards the impact head of the next layer. Said channels, or pipes, may be shaped in order to increase the fluids pressure, or velocity, as it travels down each layer, so as to maximize the force generated when the fluid impacts an impact head, which should increase the yield of each impact. In some cases, the channels between the layers may have a relatively small or decreasing diameter to increase the fluid pressure as it flows through the channel. It should be noted that the impact heads on each layer may comprise a flat, sloped, or rotating impact head, preferably each impacted head would comprise one or more embedded rotating impact head as described above, thereby gaining the benefits of both the rotating and static impact heads, note also that in these layers the surrounding static impact head can direct the flow towards the channels to the next layer, and may be sloped to help better direct the fluid flow towards said channels.

[056] In some cased these stepped, or layered, impact heads my utilize the rotating impact heads as described earlier on one or more layers. These impact heads may be positioned at the point of impact on each layer, so as to reduce the overall wear upon each layer of the impact head as described above. Wherein the rotating impact head may cover the entire layer of the stepped impact head, this is likely when the rotating impact head is in the form of a rotating cylinder, or be embedded within a larger, flat or sloped, impact head. Note that the stepped impact head may also utilize rotating impact heads at the edge of each layer to her increase the flow rate between layers by helping guide the flow towards the channel to the lower layer of the impact head. Note that such guiding rotating impact heads, may help increase the fluid pressure between layers, which in turn may increase the force applied to the fluid, thereby improving the homogenizing process by increasing the final yield of each of the lower layers.

[057] The present description provides an impact head configured to be used within a homogeniser, such as the fluid homogenisers used to produce graphene. Wherein said impact head is configured to have a geometry that can improve the efficiency of the homogeniser. In this case, improving the efficiency of the homogeniser may mean reducing the wear on the impact head thereby giving the impact head a longer operational lifetime meaning the homogeniser can be operated for longer period, before the need to preform maintenance on, or replace, the impact head. Or the efficiency may be improved by improving the overall yield of the homogeniser, for example a worn impact head could result in a loss of productivity in the homogeniser, therefore an impact head that is more resilient to wear can improve the overall yield over the impact heads operational lifespan. In other cases, the impact head geometry may be configured so that the fluid within the homogeniser undergoes multiple impacts, thereby increasing the total yield of the homogeniser, per processing cycle. In some case the impact head may utilize a combination of feature to achieve both the multiple impacts and reduced wear on the impact head.

[058] In some embodiments the impact head may be configured to utilize one or more rotating impact heads, to reduce the wear on the impact head. In these cases, the impact head is configured to rotate around at least one rotational axis, so as to spread the wear on the impact head over a wider area, reducing the risk of localized wear on the impact surface of the impact head, and thereby reducing the overall effect of the wear on the impact head. In some cases, the rotating impact can be configured to be driven by an external motor, turning at a constant rate, this way the impact head ensures that the wear is spread over a large area by exposing different parts of the impact head’s surface to the fluid flow within the homogeniser. In other embodiments the impact head may be free spinning, in these cases once a portion of the impact head becomes worn the uneven force crated by the impact of the fluid flow on that area can cause the impact head to rotate in a manner that can expose an unworn region, or at least a less worn region of the impact head’s surface to the fluid flow.

[059] Figure 1 shows an example of a rotating impact head, specifically a spherical impact head 10. The impact head is placed in the path of the fluid flow, represented by the arrows 20, wherein the fluid can impact the curved surface of the impact head at a velocity that is sufficient to produce the force need for a desired reaction within the fluid. Preferably, the width of the fluid flow is less than, or at most equal to the width of the impact head, so that the entire fluid flow impacts the surface of the rotating impact head. The spherical impact head 10, is placed within a housing 30, wherein the housing 30 is configured to hold the impact head in place, within the path of the fluid flow 20, while also allowing the impact head to rotate, as indicated by arrow 12, relative to the housing 30. By doing this the impact head can rotate to expose different portions of the impact head’s surface to the fluid flow 20, thereby reducing the overall wear to the impact heads surface, by spreading the force exerted onto the impact head over a larger area.

[060] In the present description, there are several mechanisms for rotating the spherical impact head 10. A first mechanism allows the impact head to rotate freely, wherein the impact head housing 30 is configured to allow the impact head to rotate freely whenever a force is applied to the impact head. This may allow the impact to continuously rotate under the force of the fluid flow 20, or in some scenarios, the impact head may be positioned so that it remain stationary under normal operations, however once a part of the impact head becomes worn, the localized wear can create a force imbalance on the impact head causing the impact head to rotate in a manner that can move the worn portion away from the fluid flow 20, exposing unworn, or at least less worn portions of the impact head surface to the fluid flow 20.

[061] Another mechanism is to have the impact head be driven by a suitable means, such as a motor (e.g., an electric motor), that may be housed within the same housing 30 as the impact head 10. Wherein the motor may be configured to either continuously rotate the impact head, or to rotate the impact head by a certain angle over a certain period of time, or at a predetermined time. By doing so this system aims to reduce the overall wear, and potentially prevent the formation of localized wear by spreading the wear evenly across the entire surface of the impact head.

[062] Some embodiments may use a combination of these two methods, having an impact head that is periodically driven, meaning the impact head is rotated by a specific angle at predetermined times, and then between these predetermined times the impact head may rotate freely when exposed to uneven forces. Regardless of the method used, all of these mechanisms are designed to reduce the overall wear to the impact head, by ensuring that that the force applied to the impact head is spread over a wide area, by exposing areas that are not worn, or at least areas that are less worn, to the force of the fluid flow, thereby reducing the overall wear to the impact head’s impact surface.

[063] When the impact head is rotating, the force exerted on the fluid by the impact head may be reduced, as the rotational friction generated by the rotating impact head may be smaller when compared to the force generated when the impact head is static. Additionally, when the impact head is free rolling there is the possibility that the impact head may recoil when impacted by the fluid flow 20, this may also reduce the force exerted on the fluid, which may reduce the overall efficiency of the homogeniser. Therefore, some embodiments may restrict the impact heads freedom of motion to reduce the amount of impact force lost in this way. In some embodiments, this may be achieved by replacing the spherical impact head 10, with an elliptical impact head 40.

[064] Figure 2 depicts an example of an elliptical impact head 40. The elliptical impact head 40 is designed to limit the directions in which the impact head can rotate, in the depicted example the elliptical impact head 40 is designed to rotate around its longitudinal axis, as indicated by arrow 42, the axis parallel to the fluid flow 20, as the other directions of rotation are blocked by the housing 30. Though, it is noted that the elliptical impact head 40 may be aligned differently to the depicted example. Whichever alignment is used, the purpose of the impact head is the same, that is, to only allow rotations in a limited number of directions, thereby reducing the possible force lost, due to the rotating motion reducing the frictional force applied to the impacting fluid. It is also noted that the elliptical impact head 40 may be free rolling, motor driven, or both in the same manner as the spherical impact head 10.

[065] Figure 3 depicts an alternative rotating impact head geometry, specifically a cylindrical impact head 50. The cylindrical impact head 50 is held in place, in the path of the fluid flow 20, by a housing, or support structure 60, wherein the cylindrical impact head 50 can only rotate around its longitudinal axis, as indicated by the arrows 52, which should be perpendicular to the direction of the fluid flow 20, so that the fluid impacts the curved surface of the cylinder. As with the other rotating impact heads, the cylindrical head may rotate freely, or be driven by a motor, to spread the wear over the entire curved surface of the cylindrical impact head 50. However, unlike the other designs the housing, or support structure 60, of the cylindrical head 50 may be configured to move the impact head laterally, in the direction perpendicular to the direction of the fluid flow 20. That is to say when the fluid flow does not cover the entire length of the cylindrical impact head 50, the housing may be configured to move the impact head in a direction parallel to the longitudinal axis, to expose new areas of the impact surface, in this case the curved surface of the impact head to the fluid flow 20, these movements may be performed periodically, or when a certain amount of wear is detected in the currently exposed region of the impact head. One benefit of the cylindrical impact head 50 compared to the other geometries is that the cylindrical shape can generally have a larger impact surface compared to the spherical 10, and elliptical 40 impact heads. Meaning that the cylindrical impact head 50 may have a longer operational life span than the other geometries, when using the same sized fluid flow on each. Alternatively, the cylindrical head may allow the use of a wider fluid flow, one that covers the entire length of the cylindrical impact head, which may increase the amount of fluid impact the impact head at any given time, which in turn means an increase in the amount of impacting fluid that is reacting at a given time, this may result in a homogeniser that is using the cylindrical impact head 50 having a faster rate of production, when compared to the other impact heads.

[066] In some embodiments the curved surface of the impact head may not initially be smooth, as this smooth surface reduces friction on the impact head, and in turn reduces the force applied to the impacting fluid in the fluid flow 20. Therefore, some embodiments of the rotating impact heads may include surface features to produce more friction, such as regular groves, dents or dimples, though these areas may become prone to wear. In the case of spherical 10 and elliptical 40 impact heads these surface features may be in the form of dimples, or dents, that give the impact head a surface similar to that of a golf ball. While the cylindrical impact head 50 may have groves along its length giving the impact head a shape similar to a drill bit. The purpose of these surface features is to increase the amount of friction between the impact head and the impacting fluid, this can ensure that there is sufficient force for the desired reaction within the impacting fluid. Though as mentioned there may need to be a compromise, as to how many of these features are included if any, as these features can experience a greater amount of friction, meaning they may form weak point that are prone to wear, so it may be that the wear from including these features out weight the gains made by the increased frictional force they produce.

[067] In some embodiment wherein the homogeniser uses a rotating impact head the housing around the impact head may also include a cowl, such as the cowl 70 shown in Figure 4. This cowl 70 may provide a channel between the impact head and the housing, through which the fluid may pass through, inside the channel the impact head may exert a crushing force to the fluid in the channel to help increase the yield of the desired reaction. This cowl 70, and any fluid between the impact head and the cowl 70, may also act as a bumper, preventing the impact head from recoiling when struct by the fluid flow 20, this may help reduce the amount of force loss when using a freely rotating impact head, once again increasing the overall yield.

[068] Another solution to reduce the amount of force lost by using a rotating impact head is shown in Figure 5. In this example the homogeniser is using a flat impact head 80, wherein the fluid impacts a flat static surface. In traditional homogenisers the impact surface, the surface facing the fluid flow, may have a protective/hardened layer, that helps prevent wear and increases the force exerted by the impact head. Instead, the depicted impact surface 82 comprises a one or more embedded rotating impact heads 84, these impact heads may use any of the above-mentioned geometries, and may have a cowl for each of the embedded impact heads 84. The important feature of this design is that the plurality of smaller impact heads be positioned in a manner to form a near flat surface, thereby providing more frictional force when impacted, can simultaneously allow the individual embedded impact heads to rotate, thereby reducing the wear to the impact surface. Note that these impact heads may also be designed to move laterally, in a direction perpendicular to the direction of the fluid flow 20, thereby exposing different portions of the impact surface 82 to the fluid flow 20, this may be used when the fluid flow 20 does not cover the entire impact surface 82 of the impact head 80.

[069] An alternative to the rotating impact head geometries can be the use of a layered, stepped or ziggurat shaped impact head 90, such as those depicted in figures 6 to 8. These impact heads comprise a plurality of impact heads arrange to form layers, or steps, wherein the fluid flow 20 can impact the first layer, then run off the edges of the first layer, after which the fluid falls and hits the second layer, after which the fluid may again flow to further successive layers, with the impact on each layer providing enough force to produce the desired reaction. This shape for the impact head 90 improves the overall efficiency of the homogeniser process by producing multiple impacts in a single cycle of the fluid flow 20, which may improve the yield of the process per cycle, and may remove the need for repeating cycles, meaning this impact head may remove the need to process the same fluid multiple times, to increase the yield, as this geometry produces multiple reaction impacts in a single cycle.

[070] In some embodiments, after the impacting fluid impacts a layer of the impact head 90, the fluid may flow into one or more channels located around the edge of each layer, which then directs the fluid toward the next layer of the impact head 90. The purpose of these channels can be to help increase the pressure, or the flow rate, of the fluid as it travels between layers, this can be achieved through the choice of shape, and/or diameter for the channels, for example, the channels may be conical wherein the end proximate the higher layer, is wider than the end facing the lower layers. These channels may help increase the velocity of the fluid between impacts, thereby increasing the amount of force exerted on the fluid at each layer of the impact head 90, which may increase the yield produced by each impact.

[071] Figure 7 depicts an example impact head 100 that combines the features of the stepped impact head 90 and the rotating impact head as described above. In particular the plurality of impact heads that form the layers of the stepped impact head 90 includes one or more embedded rotating impact head within the impacting surface of each layer of the stepped impact head 90. It is preferable that these embedded rotating impact heads be positioned either at the point of impact or at least proximate the point of impact. In these embodiments the embedded impact heads help to reduce the wear to each of the layers of the stepped impact head 100, by spreading the wear over the surface of each embedded rotating impact head. Note that there may also be a plurality of embedded rotating impact heads, in a similar manner to the impact head in figure 5, and it is noted that these embedded rotating impact heads may use any of the shapes described above.

[072] Figure 8 depicts another example stepped impact head 110, which utilizes one or more rotating impact heads, wherein each layer includes embedded rotating impact heads along the edge of the layer. In this example the rotating impact head are being used along the edge of the layers of the impact head 110 to act in a manner similar to a water wheel, that is to say that these impact heads can rotate as the fluid flows between layers, and in doing so these impact head may help to increase the velocity of the fluid as it flows over the edge from one layer of the impact head 110 to the next, or into channels that direct the fluid flow 20 to the next layer of the impact head. Thereby using the rotating impact heads to increase the force exerted during the impact with the next layer. As previously mentioned, increasing the fluid velocity and in turn the force generated during an impact, the yield of said impact may be increased, thereby increasing the yield, and therefore the efficiency, of the homogeniser process. Note that in this embodiment it is preferable to have the rotating impact heads be driven so as to accelerate the fluid to a desired velocity.

[073] Some embodiments of the stepped impact head may utilize rotating impact heads in both the center of the impact surface and the edges of the impact surface. In doing so the impact head is designed to both reduces wear on the impact surfaces, and increase the fluid velocity between layers, both of which can help improve the yield of the homogeniser, as described above. Note that some embodiments may instead use a layered impact head wherein each of the layers are made from one or more rotating impact head, for example the impact head may comprise a pyramid structure with a spherical 10, elliptical 40 or cylindrical 50 impact head at the tip as the initial impact surface, with a plurality of cylindrical impact heads 50 forming the lower layer. It is noted that any of the rotating impact heads may be used to form the layers, but the cylindrical shape may be preferable as they provide a larger impact surface. Thereby providing the benefits of both the rotating and stepped impact heads simultaneously.

[074] Additionally, when forming the stepped impact head from a plurality of impact heads, the space between the impact heads may form the above-mentioned channels between the different layers, the width of which can be controlled by moving the individual impact heads laterally. Further, it is noted that in some embodiments the cowls around the rotating impact head may also be used to form the channels between layers.

[075] By using the above-mentioned geometries, the present description provides an improved impact head for a homogeniser. Wherein the specific shape of the impact head improves the overall efficiency of the homogenizing process, by reducing the wear on the impact head, thereby reducing downtime, due to repairs and maintenance, while also increasing the operational lifespan of the impact head. In some embodiments, combining the features of the present description can enable multiple advantages concurrently.

[076] The present description also provides a homogeniser that includes a sloped impact head having a sloped geometry. In other words, the housing of the impact head is shaped in a manner so as to form a gap between the impact head and the housing through which the fluid being processed by the homogeniser flows.

[077] The present description provides a homogeniser designed to process fluids and aqueous suspended materials to produce graphene, or other atomic scale materials. Preferable these atomic scale materials would comprise laminar materials, examples of such materials include graphene, and graphene nanoplatelets (GNP). Wherein the homogeniser uses shear force technique on a fluid or mixture being processed to produce the desired material, for example a fluid containing aqueous suspended graphite may be processed to form graphene, while a fluid containing suspended GNP stacks may be processed to produce smaller stacks, fore example process that form GNP usually have stacks of 10-50 platelets, a homogeniser may be used to reduce the size of these stacks to a more desirable size with fewer layers, namely less than 20. In the homogeniser the mixture is injected into the apparatus at a relatively high pressure/flow rate, that then impacts upon the impact head, using the shear force of this collision to separate the materials within the mixture to form the desired atomic scale material.

[078] In a conventional impact head, the fluid flow of the mixture flows through an apparatus wherein the flow directly impacts the impact surface of an impact head, generating the shear force needed to generate the desired homogenizing reaction. After this impact, the fluid flows across the surface of the impact head wherein it may impact the sides of the impact heads housing, these secondary impacts may also provide enough force to further homogenize the mixture. Then the fluid can flow through a gap, positioned between the impact head and the surrounding housing. Wherein the fluid can continue through the rest of the apparatus, and may undergo further impacts, either with other components or by having the flow redirected towards the impact head.

[079] As the fluid flows through the gap between the impact head and the surrounding housing, the fluid may experience additional shear force, due to changes in pressure as the fluid enters and exits the gap, and from the friction with the walls of said gap. This additional force on the fluid may allow further homogenizing reactions to occur, this in turn may increase the overall yield of the homogenization reaction. In some cases, the size and shape of the gap may be altered in order to produce a desired pressure, or force, on the fluid within the gap. Though it may also prove beneficial to change the shape and size of the impact head, and/or the surrounding housing, to increase the amount of force, or pressure, applied to the fluid as it flows through the homogeniser, to further increase the yield of the homogenizing process.

[080] As previously mentioned herein, over time the impact head of the homogeniser can become worn, when this occurs the debris from the worn impact head may be carried away by the fluid flow. Wherein this debris may begin to build within the gap surrounding the impact head, until the gap becomes completely blocked. In some cases, the worn impact head may reduce the efficiency of homogenization reaction, as a result the mixture in the fluid flow may comprise larger particles which may also clot, or form deposits, that may eventually block the gap around the impact head. Currently to counteract this effect, the homogeniser process would need to be routinely stopped to replace the impact head and manually clear any blockages. It is noted that for maximum yield a homogeniser process should be continuous, so such pauses can affect the overall yield of the process. And though routine maintenance may always be necessary, there is a need for a homogeniser that requires fewer pauses in the process, and preferably provides a means to remove blockages without stopping the process.

[081] The present description provides an impact head for a homogeniser, specifically a homogeniser used to form atomic scale materials, preferably laminar materials, such as graphene. Wherein these materials are produced by using the homogeniser to process a fluid mixture, or aqueous suspendered materials in a mixture, such as an aqueous suspension of graphite, or particles of graphite, hexagonal boron nitride or molybdenum disulphide. The materials produced by these homogenisers may then be placed back into the homogeniser for further processing, to further increase the yield, or to produce a different reaction, or may be further processed to form useful materials, such as using the produced graphene to form carbon nanotube, or graphene nanotubes. The disclosed impact head is designed to help increase the yield of the homogenisation process, by providing impact heads with an improved geometry to increase the yield of the homogeniser process and may also provide a means of adjusting the size, or shape of the gaps surrounding the impact head to further increase the yield of the process. For changing this gap can help increase the amount of pressure, shear force, and/or frictional force exerted on the fluid as it exits the impact head housing. In doing this the impact head geometry may increase the probability of a successful homogenisation reaction occurring within the fluid, which in turn can increase the efficiency of the homogeniser process. Additionally, some embodiments of the impact head of the present description are designed to provide a means for removing blockages formed within the gap between the impact head and the impact head’s housing. It should be noted that in most cases the term ‘improve yield’ would refer to increasing the amount of the desired product being produced, but in some cases to improve the yield of the homogeniser process involves improving the quality of the product produce, rather than the quantity. For example, when producing GNP, the platelets form into layers, or stacks, and in many applications, it is preferable for these stacks to have fewer layers, therefore a mixture of GNP may be processed by the homogeniser to break down the stacks into small stacks, thereby improving the yield of high-quality GNP, despite the fact the number of platelets remains the same overall.

[082] The present description provides an impact head for a homogeniser, specifically a homogeniser used to form atomic scale materials, preferably laminar materials, such as graphene. Wherein these materials are produced by using the homogeniser to process a fluid mixture, or aqueous suspended materials in a mixture, such as an aqueous suspension of graphite, or particles of graphite, hexagonal boron nitride or molybdenum disulphide. The materials produced by these homogenisers may then be placed back into the homogeniser for further processing, to further increase the yield, or to produce a different reaction, or may be further processed to form useful materials, such as using the produced graphene to form carbon nanotube, or graphene nanotubes. The disclosed impact head is designed to help increase the yield of the homogenization process, by providing impact heads with an improved geometry to increase the yield of the homogeniser process, and may also provide a means of adjusting the size, or shape of the gaps surrounding the impact head to further increase the yield of the process. For changing this gap can help increase the amount of pressure, shear force, and/or frictional force exerted on the fluid as it exits the impact head housing. In doing this the impact head geometry may increase the probability of a successful homogenisation reaction occurring within the fluid, which in turn can increase the efficiency of the homogeniser process. Additionally, some of the embodiments of the impact head are designed to provide a means for removing blockages formed within the gap between the impact head and the impact head’s housing. It should be noted that in most cases the term ‘improve yield’ would refer to increasing the amount of the desired product being produced, but in some cases to improve the yield of the homogeniser process involves improving the quality of the product produce, rather than the quantity. For example, when producing GNP, the platelets form into layers, or stacks, and in many applications, it is preferable for these stacks to have fewer layers, therefore a mixture of GNP may be processed by the homogeniser to break down the stacks into small stacks, thereby improving the yield of high- quality GNP, despite the fact the number of platelets remains the same overall.

[083] In the present description, one of the preferred geometry for the impact head is a sloped, or angled, shape. These geometries include shapes such as cones, frustro conical geometries, pyramids, and frustro pyramid geometries, these geometries provide a slope, or incline, between the base of the impact head and the top surface of the impact head. For in use the narrower end, or point in the case of a cone or pyramid, of the geometry is positioned as the top surface, so that it may be used as the impact surface, meaning this surface, or point, is facing towards the fluid flow, and can be the point the fluid initially impacts within the homogeniser. After the initial impact the fluid can flow down the slopped surfaces, until them impact the housing surrounding the impact head, these secondary impacts may produce further homogenising reactions. Then the fluid may continue to flow into a gap between the impact head and the surrounding housing. It is noted that the sloped surface of the impact head ensures that the gap surrounding the impacted is shaped so that the channel formed becomes narrower as the fluid flows away from the impact surface, a combination of the fluid accelerating as it flows down the impact head slope and the pressure change caused by the decreasing size of the channel, the fluid can experience increased shear force as it flows down the channel, when compared to a linear and/or uniform channel. This increase shear force can allow more homogenising reactions to occur as the fluid flows down the channel, thereby increasing the yield of the process.

[084] Among the shapes described, one of the preferable shape is the frustro conical geometry. For the point at the top of the cone and pyramid geometries would be prone to wear, especially when placed within the fluid flow, and would therefore be a weak point and be likely to break off under the force of the fluid flow, also, if the point does wear or break, it may block the gap/channel around the impact head, which may require the process to be stopped in order to clear the gap around the impact head or can at least reduce the yield of the process. It is also noted that the frustro conical, and frustro pyramidal geometries provide a flat impact surface, which increases the force applied to the fluid during the initial impact with the impact head, which again improves the yield of the process, and is why it is preferable that the flat surface of the impact head be at least as wide as the fluid flow, so that all of the fluid impact the flat surface first. However, similar to the point of the cone and pyramid, the edges on the sides of a pyramid geometry may be worn as the fluid flows down the sides of the impact head, as the narrow edges are prone to wear, and as a result the edges may wear down producing debris that may block the gap around the impact head.

[085] One way to help overcome the problem of wear to the impact head may be to have an impact head that can rotate, wherein the impact head may rotate freely, or be driven by a pneumatic system, or motor. In either case the rotation of the impact head can help reduce wear by spreading the force exerted by the fluid on the impact head over a larger area. Also, if the impact head becomes worn, a freely rotating impact head may be rotated by the uneven force, and can help expose an unworn area to the parts of the fluid flow causing the most wear. The impact head may also utilise both free and driven rotation, have a system programmed to rotate the impact head by a specific amount at predetermined time, while freely rotating between these moments. This combined method can help ensure the force of the fluid flow is spread over the widest possible area, and that worn areas can move out of the fluid flow when necessary. It is also noted that the driving/pneumatic system may also be used to adjust the position of the impact head relative to the fluid flow, this may be used to expose different areas of the impact head to the fluid flow, and may also be used to change the size, or shape, of the gap/channels surrounding the impact head to a desired shape to maximise the force exerted on the fluid as it passes through the channel.

[086] In some scenarios, the same effect can be achieved by using a housing with a sloped geometry, regardless of the shape of the impact head. In particular the housing would comprise sloped walls to create gaps/channels around the impact head, with the same properties described above. As the sloped housing would create a channel around the impact head with a varying width/radius, and as the channel gets narrower the force on the fluid within would increase, thereby increasing the likelihood of a successful reaction occurring. The walls of the sloped housing may be shaped so as to form a conical, or pyramid space, with the fluid source at the imaginary point of said space, and with the impact head positioned within the frustrum of the conical/pyramidal space. Alternatively, the housing may be positioned to have the point of the conical/pyramidal space be at the far end of the homogeniser, relative the fluid source, so that the channels become narrower as the fluid flows away from the impact head. This way the fluid has a chance to accelerate before reaching the narrowest point of the gap between the housing and the impact head, which may increase the force exerted on the fluid within the channel. Also, it is noted that like the impact head, the conical shaped space may be preferable for the housing, as this shape would remove the narrow edges that may be more prone to wear. The housing may also be configured to rotate to help reduce wear to the housing walls in the same manner as the rotating impact head.

[087] Another method that may be utilized to reduce wear to either the impact head, housing or both, by having the part of the homogeniser being made of a tough material, such as a metallic alloy, or diamond, as such materials can be more resilient to the wear caused by the continuous force produced by the fluid flow. Further examples of suitable materials include tungsten carbide, zirconia, silicon nitride, alumina silicon carbide, and boron nitride. However, to make the entire impact head, or housing, out of such materials may be too expensive, and may prove to be impractical as some tough materials can be hard to shape into the desired geometry. To help address this issue the impact head and/or housing walls may comprise a protective layer, made from the aforementioned tough materials, positioned on the surfaces of the impact head and housing that are exposed to the fluid flow. These layers may also be made by embedding small pieces of a tough material into the surfaces of the impact head and/or housing, such as small pieces of diamonds, typically by heating the desired surface then forcing the tough material into the heated surface. It should also be noted that try to form these tough layers onto curved surfaces, such as the surface of a conical impact head and/or housing, may be difficult, as you would need to create a single, continuous curved layer.

[088] Figure 9 depicts a general example of an impact head 220 configured for a homogeniser, in particular a flat impact head, surrounded with a housing 210, 210’ with flat sides. In these cases, the fluid flow can impact on the top surface, wherein the force of the impact can cause a large number of homogenising reactions. Then the fluid can flow across the impact head 220 and impact the flat side of the housing 210, 210’, which may cause further homogenisation reactions. After these impacts the fluid can then flow down the gaps around the impact head 220, which has a fixed profile defined by the radius of the flat impact head.

[089] The Impact head 220 of Figure 9, further comprises a pneumatic system for adjusting the position of the impact head within the housing, represented on the figures by the arrows 230. In the depicted example the hydraulic system can move the impact head in a direction parallel to the direction of the fluid flow, moving the impact head 220 closer to, or further from, the fluid source. Such motion can alter the path length which the fluid must travel before impacting upon the impact head 220, this may affect the velocity of the fluid just before the moment of impact, which in turn can change the force applied to the fluid as it impacts the impact head 220, this may be used for example to counteract the effects of wear on the impact head, by moving the impact head 220 away from the source so that the fluid has a longer path and therefore more acceleration before the impact, in the case where the fluid flow downwards. In other designs the impact head may need to be moved towards the fluid source to increase the impact on the fluid, for example when the fluid is pressurised and flow upwards, or horizontally towards the impact head, resulting in the fluid decelerating the further it travels from the fluid source. This increase in the force generated by the initial impact can help compensate for the force loss due to the surface of the impact head be worn.

[090] In the example of Figure 9, the impact head 220 would be at a fixed distance from the surrounding housing 210, 210’ said distance would be predetermined to provide the most amount of shear force to the fluid as it passes through the gap between the impact head 220 and the housing 210, 210’. Though as previously mentioned these channels, or gaps, are at risk of becoming blocked, usually due to debris as the impact head 220 becomes worn. In some scenarios, this can be mitigated and/or avoided by adding further pneumatic systems, which can allow the impact head to move both vertically and horizontally. This way the impact head gains the above-mentioned benefit of allowing the impact head to move vertically, to change the fluid velocity at the point of impact. While also allowing the impact head to move horizontally, to increase the size of the gap/channel between the impact head 220 and the housing 210, 210’, to remove any blockages that have formed. This allows the operator a means to remove blockages from the homogeniser without needing to halt any ongoing processes, thereby allowing the homogeniser to continue operations while the blockage is removed. This should allow the user to minimise the yield losses caused by such blockages. [091] In another embodiment, the impact head 220 may be sloped, or angled, instead of flat, like the impact head 240 depicted in Figure 10. This angled impact head 240, may have one or more sloped/angled faces facing towards the sides of the housing 210, 210’, with the narrower end of the impact head facing the fluid flow. These angled surfaces may allow the user to change the size of the gap/channel around the impact head, by moving the impact head vertically. For, as the narrow end of the impact head is moved towards the fluid source, the base of the impact head, within the walls of the housing, becomes wider, thereby reducing the size of the gap between said impact head 240 and the housing 210, 210’. Similarly, by moving the end of the impact head 240 away from the fluid source, the base of the impact head, within the house, becomes narrower, thereby making the gap between the impact head 240 and the housing 210, 210’ wider. This mechanism may be used to widen the channels to remove blockages, thereby removing the need for the horizontal movements described above. This mechanism may also be used to adjust the size of the gap to an ideal size, wherein said ideal size produces the optimal amount of shear force for the fluid being processed, thereby producing a higher yield. This may be necessary in processes where different fluids can pass through the same homogeniser, or in systems where a fluid is processed and then feed back into the system for further processing cycles. As the average molecule size within the different fluids may require different shear forces for the desired homogenising reaction. Likewise, when a fluid is fed back into the homogeniser for further processing, it would be understood that the processed fluid would contain smaller molecules on average compared to the original fluid, and therefore more shear force may be needed to react the unreacted fluid from the original cycle of the process, or to cause a further desired reaction within the processed fluid, which requires a different level of shear forced compared to the original reaction.

[092] Figure 11 depicts an embodiment wherein the impact head 250 is flat, and instead it is the sides of the housing 260, 260’ that are sloped/angled. Note that in this embodiment, the narrow ends of the housing walls, meaning the end of the housing with the largest gap between the housing walls, faces the impact head 250. With this arrangement, the impact head can still change the size of the gap between the impact head 250 and the housing 260, 260’ by moving vertically, and as before the gap can become smaller as the impact head 250 moves towards the fluid source, and the gap becoming wider as the impact head 250 moves away from the fluid source. [093] In some scenarios, the corners of the impact head 220, 240, 250 may be prone to wear, as these areas can be relatively thin compared to the bulk of the impact head 220, 240, 250. If the corners are worn down or broken off by the force of the fluid flow, they may create enough debris to block the channels between the impact head 220, 240, 250 and the housing 210, 210’, 260, 260’. And if the corner breaks off entirely, the broken piece of the impact head may be significantly larger than the channel, and therefore cannot be unblocked by moving the impact head 220, 240, 250 alone, thereby requiring the process to be stopped as the blockage is removed, which can cause the operator to lose processing time and therefore reduce the yield of the process. One way to address this may be to use an impact head with a rounded shape, such as the cylindrical impact head 220 in Figure 9, or the frustro-conical shaped impact head 240 of Figure 10, as such rounded impact head would not have these vulnerable corners, though it is noted that the edges of the impact surface may still be prone to wear.

[094] A further embodiment may use both an angled/sloped impact head 270, and an angled/sloped housing 260, 260’, thereby removing the corners that were most at risk of breaking, such as the example depicted in Figure 12. As with the previous embodiments, the impact head 270 may move vertically, to change the size of the gap between the impact head 270 and the surrounding housing 260, 260’, to change the shear force acting on the fluid as it flows through said gap. However, this configuration has removed the impact head corners proximate the housing, replacing them with an angled surface, which is less likely to wear under the force of the fluid flow within the gap. This in turn reduces the risk of the gap/channel between the impact head 270 and the housing 260, 260’ becoming blocked.

[095] Figures 13A and 13B depict other embodiments, wherein the impact head 240 has a frustro-conical shape, similar to the one shown in Figure 10, and the surrounding housing 260 has sloped walls, however In Figure 13A slopes of the impact head 240 and housing walls 260, 260’ are parallel, like the depiction in Figure 10, while in Figure 13B the slope of the impact head 240, and the housing 260, are not parallel. This means in the embodiment of Figure 13B, the width of the channels between the impact head 240 and the housing 260 is not constant, but instead becomes narrower up to a chokepoint/bottle neck formed between the housing 260 and the base of the impact head. In the other embodiments the channels still comprised this choke point at the base of the impact head, which would move as the impact head is moved within the housing, however the channel width before and after this point would be constant if the slopes of the impact head 240 and housing 260 were parallel. However, with these non-parallel slopes the channels become narrower as they approach the chokepoint. Such channels may be used increase the pressure of the fluid as it flows through the channel, as this may help increase the amount of frictional/shearing force exerted on the fluid as it reaches the chokepoint, thereby adding force gradually over the length of the channel, rather than a single sudden impact of force at the chokepoint, wherein the gap/channel is at its narrowest. This may help to improve the overall yield by increasing the probability of a successful homogenising reaction within the channel.

[096] It should also be noted that each of the depicted impact heads 220, 240, 250, 270 have a flat impact surface on the side facing the fluid flow, with the sloped surfaces surrounding the impact surface. It is noted that this is preferable, as the flat surface provides more frictional force for the initial impact increasing the yield of said impact, also because if the tip of the impact head was a narrow edge, or point, it may be prone to wear, and may possibly break off, thereby blocking the gap around the impact head. Therefore, it is preferable that the impact head has a flat impact surface, more preferably with a width, or radius, similar to that of the fluid flow, so that all of the initial impact occur on the flat impact surface.

[097] Figure 14 depicts an embodiment similar to that of figures 10 and 13, however in this example the impact head 280, has a conical geometry, specifically a cone with a rounded, or domed, point. As previously mentioned, if an impact head 220, 240, 250, 270, 280 was to have any points, corners or edges within the fluid flow these points could form weak points that are prone to wear and may even break off entirely blocking the gap between the impact head 220, 240, 250, 270, 280 and the housing with the debris formed. One way to help reduce the risk of this happening, as previously mentioned, was to allow the impact head 220, 240, 250, 270, 280 to rotate within the housing to help spread the force exerted on the impact head over a larger area. Another possibility is to round off these potential weak points, like the point of the cone in Figure 14. This way again the force of the fluid flow is spread over a wider area, thereby reducing the force on these potential weak points, reducing the risk of wear. One potential drawback of such designs is that the rounded points would exert less force onto the fluid during an impact, so a user would need to calculate if the reduce maintenance costs caused by the reduces wear on the impact head 280, would counteract the potential loss of yield caused by the reduced force, for as stated a flat impact surface provides the most force during the initial impact. However, in regard to corners and edges, or any points that are not on the initial impact surface, this round should have little effect on the yield, and as stated may reduce the cost of maintenance by extending the operational lifespan of the impact head 220, 240, 250, 270, 280, due to the reduced wear.

[098] Another means of reducing wear mentioned above, was to include a tough material layer, or to embed particulate of such a tough material into the surface of the impact head 220, 240, 250, 270, 280, and /or the surface of the housing walls 210, 210’, 260, 260’. However, such layers can be difficult to form on curved surfaces, such as the curved sides of a conical, or fustro-conical impact head, instead it would be preferable to have an impact head with flat surfaces that these protective layers could be easily grafted onto. For this purpose, a pyramid, or fustro-pyramid shape may be preferred. Further, it may also be preferable that these pyramidal shaped impact heads have a base with many sides, such as the example impact head 290 depicted in Figure 15. For such a pyramidal shape can typically have more obtuse, or wider, angles between the flat faces, such edges would be less prone to wear compared to narrower, more acute, edges. Such impact head 290 may also utilise rounded corners/edges, and impact head rotations to further reduce wear.

[099] The present description also provides an optional homogeniser control system, as described hereinbelow, for controlling a homogeniser configured to process a liquid composition comprising suspended material for the purposes of reducing the size of that suspended material to provide a finished product. Wherein the control system comprises a processing unit configured to, regarding the specific liquid composition being processed, receive a measure of particle size of suspended material in liquid composition, receive a measure of pressure of the liquid composition being processed. This way the control system can confirm the initial status of the reactant, in this case the suspended material, entering the homogeniser. Further, by using the initial particle size, the control system may determine the desire pressure needed to produce sufficient force needed to produce the desired reaction with the homogeniser.

[0100] The processor can be further configured, regarding the liquid composition being processed, to control means to adjust one or both of the incoming pressure of the liquid processed, and/or the gap in the homogeniser head primary providing the homogenisation action determined using one or both of the received measures. This refers to using the control system to adjust the system parameters of the homogeniser to increase the likelihood of a successful reaction. For most homogeniser systems comprise a pressure chamber, configured to receive the liquid composition and to rise the pressure of said liquid composition to a desired level. This pressure increase can apply some force to the liquid which may help start the required reaction, for example when producing an emulsion like milk, the initial pressurisation may start the ablation process. But more importantly can provide a force to move the liquid through the rest of the homogeniser at a specific velocity, in most cases a higher velocity is preferred as this can produce a greater force to break down the suspended material. However, it should be noted that this is not always the case, for example when producing GNP stacks there can be a desired stack height for the final product and separating each of the platelets may not be desired, therefore there can be a desired force/pressure to produce stacks with a height within a specific range.

[0101] From this pressurised chamber the liquid is released into a second chamber wherein a further force can be applied to the liquid to produce the desired homogenisation reaction. There are different ways such a force can be applied, in some cased the liquid may enter a grinding apparatus, or flow through a centrifuge like device. However, in the preferred embodiment, the homogeniser can utilise an impact head for producing the desired force. Where in the liquid is feed into a conduit that directs the liquid to one or more impact surfaces of the impact head, the force of the impact providing a shear force to the suspended material within the liquid, thereby producing the desired homogenising reaction. After the impact the liquid may then flow out of the homogeniser. In some cased the liquid may flow into channels surrounding the impact head, wherein additional pressure may be exerted onto the liquid to possibly produce more reactions, and wherein the liquid may be directed to further impact surfaces. In such system the control system is configured to adjust the size of these channels by adjust the size of the gap between the impact head and its surroundings, which may comprise a housing or adjacent impact heads. As mentioned the size of the channel, or in this case the gap forming the channel, can affect the pressure of the liquid as it leaves the homogenising chamber, and may use this pressure to apply additional force on the liquid to increase the chances of a successful reaction and thereby increase the efficiency and yield of the homogenising process.

[0102] It should be noted that the determination of the initial size of the suspended material can help determine the amount of force needed to produce the required reaction. In response the control system may set the conduit pressure to a level required to produce the required amount of impact force, further using this information, and/or the initial liquid pressure measurements, the control system can adjust the gap around the impact head to either produce more force, or to ensure the liquid returns to the desired pressure it was under whiles in the pressure chamber. By doing this the control system can ensure that the liquid within the homogeniser is under a constant force, and that there is sufficient force to produce the desired product.

[0103] In some scenarios, the homogeniser may be required to process a wide range of different materials, in some cases the suspended material may comprise a solid which is then suspended within a liquid medium that can carry the solid through the homogeniser, at which point the homogeniser may be configured to break down the solid material, to produce a desired reaction between the solid material and the suspension liquid, to ensure an even distribution of the solid within the liquid medium, or otherwise process the solid to submicron dimensions. Though in other cases the suspended materials may be different liquids that required the homogeniser to combine through a reaction, or to ensure an even distribution, or again process to submicron dimensions. Depending on the material being used, and the desired effect on said material, the control system may be configured to set the parameters of the homogeniser to produce the force/pressure necessary.

[0104] In the cases where a solid material is used the control system may also be required to determine the initial size, volume, or other properties that may affect the force needed. For example, the suspended solid may be formed from particles, pieces, or crystals, that may come in various sizes, and depending on the size of the initial solid different amounts of force/pressure can be needed. Therefore, the control system may comprise a means for determining the size of the suspended material, such as a means for preforming spectroscopy. Methods of spectroscopy that may be used include light scattering, which uses the scattering of electromagnetic radiation to determine the atomic make-up of the liquid composition, Raman spectroscopy, which uses the absorption and emission of electromagnetic radiation to determine the atomic scale structure of the liquid composition, this may for example determine the exact atomic structure of a graphene sample, for example the number of graphene layers and the types of edges of the layer which may be ‘arm-chaired’ or ‘zig-zagged’, the spectral analysis may also look into absorption spectrums when the system requires wavelengths outside of light, and IR, frequencies. For example, many nanostructures can have intermolecular bonds that can absorb low frequency waves, typically radio waves, the larger the structure to more the low frequency waves can be absorbed, so this absorption, or other absorption spectrum may be used to determine the initial size of the atomic scale structures present in the liquid composition. Further, it should be noted that in many biological and medical field fluorescent tags are used to mark certain reagents and materials, which give off light under certain conditions, such as exposure to LIV, therefore when the homogeniser processes such material it may use an emission spectrum to detect the tags and provide a measure of the amount of the tagged material is present in the suspension.

[0105] In the cases wherein the material to be processed in a solid, it is often in the form of a laminar material, such as graphite, which is capable of being delaminated by the homogeniser to form desired atomic scale structures, in this case the delamination of graphite may form different graphene structures, such as GNP, graphene sheets, or nano tubes. However, it is noted that there are other laminar materials that can be processed with a homogeniser, such as hexagonal boron nitride or molybdenum disulphide, or materials may include layered silicates, perovskites, niobates, MoOs, MnCh, RuC>2, TiC>2, Pbl2, MgBr2, M0CI2, RuCh, M03S3, NbSs, TiSs, TaSs, Mo ₃ Se ₃ , NbSe ₃ , TiSe ₃ , TaSe ₃ , Mo ₃ Te ₃ , TiTe ₃ TaTe ₃ Bi ₂ Te ₃ , Bi2Se3, and others materials which normally take the form of 2D layered materials of the form MX2 where M is a transition metal and where X is one of silicon, selenium or tellurium. Such delamination can be performed easily within a homogeniser, additionally different homogenisers can be used to scale the production of such delaminated materials to a desired scale, from small lab samples, to large industrial scales, simply by changing the size of the homogeniser.

[0106] Similarly, when using the homogeniser to produce a suspended liquid material, which is most likely the case when using the homogeniser to produce emulsions, such as milk, the control system may be configured to process the ablation, or reaction, of the suspended liquid to submicron dimensions, often through spectroscopy methods such as light scattering. As with the solid materials, these measurements can help determine the initial state of the reactants entering the homogeniser, from which the required pressure, and/or force, to be exerted onto the liquid can be determined. From this the control system may use the control means to adjust the homogeniser parameters to produce the required pressure/force. Such processes may also be used on the final produce to ensure the desired emulsion has formed, or determine that the liquid needs to be processed further.

[0107] Regardless, of the type of material being processed, the control system requires a means of adjusting the homogeniser in response to the measurements detailed above. In the preferred embodiment, the means of adjustment would be in the form of a pneumatic system. In particular, a pneumatic system configured to move at least a first part of the homogeniser impact head relative to the second part of the impact head, thereby adjust the gap surrounding the impact head. As mentioned above the change in the gap size may be used to increase the pressure of the liquid after it has impacted the impact head, to help produce additional homogenising reactions. This mechanism may also be used to widen the gap in case of blockages in the homogeniser, which may occur in the gap, especially when using solid materials within the liquid composition. The same system may also be configured to move the impact head relative to the conduit, that directs the liquid to the impact head, as adjusting the travel distance between the pressurised conduit and the impact head may change the amount of force exerted on the liquid when it impacts upon the surface of the impact head. As noted, different reactants require different amounts of force, therefore the control system requires a mean to control and/or determine the amount of force that can be exerted onto the liquid composition, especially in cases where the smallest product is not the most desirable, such as the GNP stacks or nanotubes, as in these cases more force is not necessarily better.

[0108] In another aspect of the control system, is the need to measure parameters other than the initial state of the liquid composition. In some cases, the control system may be configured to determine a pressure difference between the incoming liquid, from the pressure chamber, and the outgoing liquid after impacting the homogeniser impact head. This pressure change may help to determine if the desired reaction has occurred, as in most cases the suspended material should be decreasing in size which in turn may result in the pressure decreasing, therefore meaning the pressure change could be used to determine if the desired product is produced. Alternatively, as mentioned the homogeniser initially set the pressure of the liquid to a desired value to exert force on the liquid, the control system may similarly control the size of the channels the liquid travels through to adjust the pressure of the liquid as the passes through the homogeniser, therefore the control system may be configured to maintain the desired pressure throughout the homogeniser, which would mean adjust the homogeniser so that there is no pressure drop between the different pressure measurements, or at least close to no change between the different points. By maintaining the desired pressure, the liquid is under a constant force which may increase the likelihood of a successful reaction occurring, which in turn may increase the yield of the homogeniser.

[0109] Another factor to consider when monitoring the homogeniser, is the temperature of the liquid composition. In many cases, it may be desired for the liquid to be at a higher temperature, as this can give the particles more kinetic energy which may reduce the force needed to break down the suspended material, or to produce the desired reaction. However, this may not always be the case, especially when dealing with bio-chemical materials, as a higher temperature may result in certain materials becoming denatured, additionally if the temperature falls too low this may also adversely affect some bio-chemical materials. In these cases, the control system may need a means of monitoring the temperature of the fluid throughout the homogeniser, or at least within the pressure chamber, to ensure the temperature of the reactants remains within desired parameters, which may be in the form of a desired range, a lower threshold, or an upper threshold, depending of the materials being used.

[0110] Further to monitoring the temperature, the control system may comprise a means of controlling the temperature. Such temperature control means may comprise at least one of, a heater, heat sink, radiator or cooler. Wherein the temperature control means may be coupled to the pressure chamber to control the temperature of the liquid composition before it enters the rest of the homogenisers. Some embodiments may also have such temperature control means couple to a region of the homogeniser, that is downstream from the impact head, so that the temperature of the product produce may also be monitored and controlled.

[0111] In addition to monitoring the parameters of the liquid produce by the homogeniser, including the pressure, viscosity and/or temperature of the product, the control system may also include an off-set channel, which collects a sample of the product for additional analysis. This further analysis may involve preforming spectroscopy on the sample to determine the content of said sample, this may include light scattering and/or Raman spectroscopy, or looking at absorption/emission spectrums of the product. The result of this analysis may be compared to predetermined results, or the results from the analysis of the initial liquid composition, to determine the content of the product. Any of these data points may be used to determine if the desired reaction has occurred, and may be analysed to determine the yield of the reaction. From here the control system may be configured to detect when the reaction has failed, or when the reaction has reached a desired yield, from this the control system may determine if the product produced is ready to be extracted, or if it needs to be recirculated back into the homogeniser for further processing. In some case this final determination on the state of the product may be indicated to the user. In other cases, the control system may be configured to automatically recirculate the product, or at least part of the product using a diverter, to feed the product back into the homogeniser, when the reaction has failed, or when the yield is below a predetermined threshold. [0112] As mentioned, the control system may monitor certain parameters of the fluid within the homogeniser, and where possible may adjust such parameters to a desired value, this is also true of the fluid with the diverter. More specifically, the control system may be configured to adjust the size of the channels forming the diverted to keep the recirculating liquid at a desired pressure before re-entering the homogeniser. Further, the controller may have a temperature control means comprising at least one of, a heater, heat sink, radiator or cooler, to maintain a desired temperature for the recirculating liquid. However, it is noted that after being pressurised and undergoing the impacts within the homogeniser, it is likely that the product would have an increased temperature after processing, so in the case of a temperature control means for the diverter, said means may only require a cooler, or other means of lowering the temperature of the product.

[0113] In some cases, the desired reaction may require a pressure beyond the upper limits of the pressure chamber, whether this limit is the actual limit of the pressure chamber or a safety limit for operating such a chamber, or alternatively the desired reaction for the homogeniser may produce a higher yield if the pressure could be increase beyond such limits. Therefore, the control system may configure a means to produce such increased pressure, in particular the control system may comprise a means to pulse the pressure of the liquid conduit as it enters the homogeniser, or at least the chamber comprising the impact head. Such pressure control means may be couple to an outlet of the pressure chamber, or to the conduit that directs the liquid to the impact head. It should be noted that these pulses may be controlled by the impact head directly, via systems such as pressurised valves, or indirectly by means of oscillation of the pressure chamber or other parts of the homogeniser, such as channels the fluid flows through. In some cases, as the homogeniser operate over time, the regular movements of the homogeniser components form a series of vibrations, which over time may reach a form of resonance that provide the required oscillations to the liquid with the homogeniser to pulse the pressure.

[0114] These means of pulsing the pressure provides peak points within the flow of the liquid where the liquid is at a higher pressure, and therefore can experience a higher force within the homogeniser, increasing the likelihood of a successful reaction occurring, and possibly increasing the yield of the reaction. However, in between these peak points can be pint of low pressure, which can likely fall below the pressure produced by the pressure chamber, which can have less chance of a successful reaction, and may even fail to react at all. Such low points within the fluid flow can likely need to be processed again by the homogeniser. That is why it is preferable that such pulsed systems be used alongside the aforementioned diverter, that may recirculate portions of the fluid flow. Moreover, the control system may be configured to synchronize the pressure oscillations and the diverter, especially as the preferred pressure changes can be in the form of regular oscillations. This means that the control system can set the diverted to automatically extract the product produce at the low-pressure points to be recirculated into the homogeniser, thereby reducing the yield loss due to the inconsistent pressure.

[0115] In some embodiments, the control system may be configured to measure the pressure at different points within the homogenising process beyond the initial pressure chamber and in the gap, or channels, downstream from the homogeniser impact head. More specifically, the control system may be configured to measure the pressure of the fluid immediately before entering the chamber containing the impact head, this may be for example the pressure of the fluid within the conduit, which directs the flow towards the impact surface, as this pressure can determine the velocity of the liquid as it enters the chamber, then using the distance between the impact head and the conduit, the control system may determine the velocity of the liquid at the moment of impact. This in turn may be used to calculate the force exerted by the impact of the fluid onto the impact head. Allowing the control system to ensure that the force exerted is sufficient for the desired reaction. Further, the control system may comprise a means of adjust the force of the impact. This may be in the form of a means to adjust the pressure of the liquid within the conduit, thereby changing the initial velocity of the fluid, and/or and means of changing the distance between the impact head and the conduit, which in turn affects the acceleration of the liquid before the point of impact.

[0116] The control system may further comprise a means of measuring the pressure of the fluid as it leaves the impact chamber, in particular a means of determining the pressure of the liquid with the gap between the impact head and their surroundings, as the fluid may have additional force exerted onto it, by increasing the pressure within these gaps. Therefore, the control system may also comprise a means for changing the size of the gaps surrounding the impact head, in doing so the control system can change the pressure of the liquid leaving the impact chamber to a desired level, using the measurements to monitor this change. Additionally, the pressure reading from the gaps may be used as a means of detecting blockages within the impact chamber, at which points the means that control the gap size may move the impact head in a manner that would widen the gap allowing the blockage to be removed. In some cases, the impact head may be configured to use a back pressure build up to remove blockages, the control system may also comprise a means of monitoring and controlling such back pressure.

[0117] As mentioned earlier, the control system may take spectroscopy readings for both the initial liquid composition and for the product produce. By comparing these readings to one another, and/or to known data sets, which may be stored within a memory of the control system, the control system may determine the chemical make-up, and/or structure of the liquids tested. In particular this method may be used to determine the percentage yield of the process. Specifically, using the spectrums of the product to determine the percentage of the product volume that comprises the desired product. From this determination the control system may determine if the yield is within a desired range, or at least above a predetermine threshold. If the product meets the required yield the product can be extract, if not the product can be recirculated into the homogeniser as described above. In some cases, the control system may first determine the amount of suspended material in the initial liquid, from which the control system may determine a maximum yield, from which the desired yield ranges may be determined.

[0118] Additionally, the spectroscopy of the initial liquid composition may be use to ensure that there is sufficient suspended material for the process, and determine the size of the initial suspension material as this may affect the amount of force needed for the desired reaction. Based on the determination of the size of the suspended material, the control system may adjust the components of the homogeniser to produce more, or less, pressure and force in order to produce the desired reaction, such as changing the pressure in the pressure chamber and/or conduit, or by moving the homogeniser impact head to increase or decrease the gap surrounding the impact head, and the distance between the impact head and the conduit.

[0119] It is also noted that some of the materials produce by the disclosed homogeniser may be desired for their conductive properties, be it thermal or electrical, for example graphene is often desired for its high electrical conductivity. Therefore, the control system may also comprise a means of measuring the conductivity of the liquid composition at different point in the homogenising process. From which the control system may determine the amount of desired product within the liquid composition at that point. For example, when using a homogeniser to break down graphite into graphene, the control system may be configured to measure the initial conductivity of the liquid, before the homogenising reaction, to set a base line and possible to determine the amount of suspended material within the liquid composition. Then the control system may determine the conductivity of the product produced by the homogenising reaction. The product’s results may then be compared to a predetermined threshold, or the initial liquid results, to determine if the reaction was successful, and may also be used to determine how much of the desired product was formed.

[0120] Note that in the case of delaminating stakes of nano materials, such as using a homogeniser to shorten stacks of GNP, the previously mention spectroscopy analysis may look very similar for both the initial and desired stacks, due to having the same chemical make-up and similar physical structures. However, in such cases the conductivity of the stacks change, this is why the smaller stacks are often desired over the larger ones, therefore by measuring the conductivity of the fluid the control system may be able to monitor changes within the liquid composition that would be more difficult to determine with spectroscopy alone. It should also be noted that in some cases the desired product may be less conductive than the initial material, but the same process of checking the measurements to predetermined values, and/or other measurement, would still apply.

[0121] It is also noted that the impact head within the homogeniser may become worn over time. The control system may be able to monitor this wear, for example when taking spectroscopy of the product the control system may be able to determine if debris from the impact head is present within the liquid. Further, some homogenisers may be designed to reduce the risk of such wear on the impact head, in particular the homogenisers may be configured to move the impact head relative to the flow of the liquid composition, to exposed different portions of the impact head to the flow, or the homogeniser may be configured to rotate the impact head, either way the homogeniser has a means of spread the force on the impact head over a wider area. In such homogenisers, the control system may further comprise a means of controlling the movements of the impact head, typically using a pneumatic system to move the impact head laterally and/or to rotate the impact head, either continuously or at predetermined intervals.

[0122] In some homogenisers the impact head may rotate freely, in such cases the impact head is usually symmetrical, and therefore may not rotate at first if to liquid flow is distributed evenly. However, once such an impact head becomes worn, there can be an imbalance in the force exerted on the impact head from the liquid flow, this imbalance can cause the impact head to rotate in a manner to more the worn region away from the flow. The control system may be configured to monitor this rotation, using parameters such as the angular velocity and frequency of such rotations to determine how worn the impact head may be. If the determined wear reached a predetermined threshold the control system may be configured to warn the user that the impact head needs replacing and may even stop the homogeniser entirely until the impact head is repaired.

[0123] Figure 16 shows an example of a homogeniser system that may be controlled with a control system 370. The homogeniser comprises two inlet chambers 310, 320, the first chamber 310 containing the material that needs to be suspended and the second chamber 320 containing the liquid that can be used to suspend the material from the first chamber 310, when forming the liquid composition. In some systems there may be a third chamber in which the liquid composition is formed before entering the rest of the homogeniser, there may also be additional inlet chambers when the liquid composition comprises more than two materials. It is noted that the control system 370 may be configured to measure the amount of each material entering the homogeniser from each of these inlet chambers 310, 320, to determine the chemical make-up of the liquid composition, and may also be used to determine variables such as, total volume of the liquid composition, the percentage volume of the material to be processed, and the expected yield of the process.

[0124] In the depicted system, these chambers 310, 320 feed materials into an initial pump 330. The pump 330 replaces the pressure chamber mentioned above, as it serves the same purpose of getting the liquid composition to a desired pressure before entering the rest of the homogeniser. It should be noted that the pump 330 may also act as a mixer, forcing the different materials together to form the liquid composition. Though as previously mentioned there may be a separate mixing chamber for forming the composition, and a chamber designed to store the liquid composition at a desired pressure before being pumped into the rest of the homogeniser. It is noted that the cases that use the pump 330 as the mixing/pressure chamber may be preferable as it has fewer components and is therefore simpler to construct and maintain. However, a system with a separate mixing and/or pressure chamber may be preferable, as such systems can store large amounts of liquid composition, regardless of the rate of production of the homogeniser. Also, these mixing/pressure chambers also allow the control system 370 to preform measurements on initial material, and composition, to help set baselines and ranges for the homogeniser’s parameters, and allow the control system 370 to take samples of the initial composition for spectroscopic analysis. [0125] From the pump 330, the liquid composition enters the homogenisation chamber 340. The homogenisation chamber 340 contains the apparatus that can exert a force onto the pressurised liquid composition to produce the desired reaction. This apparatus may be in the form of a grinder, or centrifuge. However, in the preferred embodiment the apparatus takes the form of one or more impact heads and their surrounding housing, like the ones described herein.

[0126] With regard to the control system 370, the control system 370 may comprise a means of adjusting different components within the homogenising chamber 340, the control system 370 may also monitor different parameters of the liquid composition as it enters and exits this chamber, such as the liquid’s pressure, viscosity, particle size/structure and temperature, as changes in these values may indicate a successful reaction, or in the case of the temperature may indicate parameters that may hinder the reaction, for example if the temperature or pressure is beyond a desired threshold the material within the composition may become denatured. Further, the control system 370 may comprise a means on moving the impact head, and/or changing the size of the gaps and channels used to exit the chamber, both of which may change the amount of force exerted onto the liquid as it flows through the homogenising chamber 340. This is typically achieved using a pneumatic system.

[0127] In some embodiments, the pneumatic system can be coupled to the impact head, allowing the control system 370 to move the impact head. The control system 370 may be configured to further control the force of the impact by adjusting the pressure of the liquid as it enters the homogenising chamber 340, which in turn changes the initial velocity of the liquid as it enters this chamber, which again effects the liquid’s velocity at the moment of impact.

[0128] In addition to adjusting the impact head, the control system may similarly use a pneumatic system to instead reposition the conduit, or the housing, to again change the force of the impact, or the pressure applied to the liquid as it exits the homogenising chamber 340. The control system 370 may also comprise a means of controlling the temperature of the liquid as it enters and/or exits the homogenising chamber 340, these means may comprise at least one of a heater, radiator, cooler or heat sink, so that the liquid may be kept at within a preferred temperature range. This may especially be the case for the liquid leaving the chamber as the force and pressure applied to the liquid composition may likely cause the temperature of the fluid to increase, as mentioned this could result in certain biological materials denaturing, and may also cause undesired reactions in certain chemical reactants. Similarly, the user may wish to heat the liquid before entering the homogenising chamber 340, as the increased temperature may increase the likelihood of a successful reaction, due to the reactants having increased kinetic energy prior to impacting upon the homogeniser impact head.

[0129] From the homogenising chamber 340 the liquid product 390 formed by the homogeniser may flow to one of a pump 350 and/or control valve, at which point the liquid may either be release from the homogeniser system, or the liquid may be recirculated into the homogeniser for further processing. It is noted that in some systems there may be a diverter configured to redirect the liquid to be recirculated. The control system 370 being configured to operate the pump 350, valves and/or diverters in order to direct the flow of the product 390.

[0130] In order to determine if the product 390 is ready, or needs to be recirculated, the product 390 may be stored within the pump 350, diverter, or another chamber, wherein the control system 370 may analyse the product 390. Alternatively, the homogenising chamber 340 may have an off-shot channel which collects a sample of the product 390 for analysis. This analysis of the product 390 may include monitoring key parameters, such as particle size, temperature, pressure, conductivity and/or viscosity of the stored product 390, which may be achieved using one or more sensors 380, 382, 384 coupled to the homogeniser system, which communicate data to the control system 370, ensuring that each of the measured values are either within a desired range, or above a predetermined threshold. Also, the control system 370 may perform as spectroscopy analysis on the product 390, or a sample of the product, using the result of the spectroscopy analysis to determine the chemical makeup, and or atomic scale structures present within the product 390, to determine whether the homogenising reaction was successful, as well as determining the percentage yield of the homogeniser process. This may be achieved by the control system 370 comparing the spectroscopy results, with known results stored within a memory of the control system 370, or comparing the results to the same spectroscopy results of the initial liquid composition. From these results, the control system 370 may determine if sufficient product has been formed. If there is sufficient product in the final liquid composition, then the control system 370 may release the liquid product 390, if not, or if the reaction was not successful, the control system 370 may recirculate the product 390, diverting or pumping the liquid product to an earlier point of the system, either the pressure chamber, homogenising chamber 340, or the conduit of the homogenising chamber 340. [0131] In the depicted system there is a chiller 360 positioned on the path of the recirculated fluid. It is noted that the control system 370 may be comprise means of adjusting parameters of the recirculating product 390. As previously mentioned, the control system 370 may monitor parameters that may affect the likelihood of a successful reaction such as the liquids temperature and pressure. If the desired reaction was not successful, or if the yield was too low, the control system 370 may be configured to not only recirculate the fluid but also to adjust these parameters to increase the yield or the chance of a successful reaction. This may include using temperature controlling means, such as the depicted chiller 360, or other means such as heaters and radiators, to adjust the temperature of the recirculating fluid. It may also include using a pneumatic system to adjust the size of the channel the recirculating fluid travels through to adjust the pressure of the fluid, it is also noted that the pump 350, valve or diverter may also be used to adjust the pressure of the liquid product 390 before it recirculates. Such feature may be necessary when the recirculating liquid goes straight to the homogenising chamber 340, as the product 390 would not enter the initial pump 330, or pressure chamber wherein these parameters were initially set. It is also noted that in the case of a failed reaction, or a reaction with too low a yield, the control system 370 may adjust the thresholds of different parameters to increase the likelihood of a successful reaction, these adjusted thresholds may then be stored within a memory of the control system for use in future processes. However, in such systems there can be some thresholds stored within the control system that cannot be altered, for example thresholds due to safety and operational limits, and threshold to prevent denaturing of the material to be processed.

[0132] It is also noted that the control system 370 may be configured to automatically recirculate the liquid composition, based on specific conditions. For example, the system may be configured to automatically recirculate the liquid composition a fixed number of times before testing the product 390, with the assumption that each cycle can increase the overall yield, but with diminishing increases each time. In some systems, in order to increase the pressure of the liquid composition, the pressure of the composition may be pulsed. In such cases the pulsed liquid can have both areas of high pressure and low pressure, the high- pressure regions can have an increased chance of a successful reaction, while the low- pressure regions are more likely to fail to react. In such cases the control system 70 may be configured to automatically recirculate the liquid from the low-pressure regions of the flow, this may be achieved by using regular oscillations to pulse the liquid composition at a steady rate, meaning the changes in pressure follow a predictable pattern. At which point the pump 350, valve or diverter, that recirculate the liquid can be synchronised with the regular oscillations to recirculate the low-pressure liquid. This can help counteract the negative effect of the low-pressure regions, on the yield of the homogeniser process.

[0133] It is also noted that in some homogenisers, the one or more impact heads within the homogenising chamber 340 may be configured to rotate, as described herein. This rotation may be driven by another pneumatic system, and/or the impact head may be configured to freely rotate. Regardless of the mechanism the purpose of this rotation is to help prevent wear to the impact head, by spreading the force exerted by the liquid composition over a larger area. In the case where the rotation is driven, this rotation may be controlled by the control system 370 using the aforementioned pneumatic system. In the cases where the impact head freely rotates, the control system 370 may monitor the rotation of the impact head, for as the impact head becomes worn, these worn portions can create a force imbalance on the impact head thereby changing the rate of rotation of the impact head, the control system 370 may detect these changes and alert to user to the severity of the wear on the impact head. The control system 370 may also be configured to detect a threshold wear level, wherein once the wear increases beyond such a threshold the control system 370 may stop the flow of the liquid composition to that impact head, until it is replaced. The control system 370 may also keep a record of how long each impact head has been in operation and alert the user to preform maintenance on the impact head once a pre-determined amount of time has passed, this maintenance may include advising the user to replace the impact head entirely.

[0134] The depicted system also includes a plurality of valves 400, 402, 404 at various points throughout the system. The valves 400, 402, 404 can be used to control the flow of the liquid composition through the system. It is noted that the valves 400, 402, 404 may also be used to create points wherein the flow of the liquid composition can be stored until a desired pressure is reached. The valves 400, 402, 404 may also provide additional channels, wherein a sample of the liquid composition, or liquid product 390, may be collected for analysis. Additional, around these valves 400, 402, 404 the system may include sensors for determining the key parameters of the liquid composition, such as particle size, temperature, pressure and viscosity. Wherein the sensors can provide measurements to the control system 370. Such sensors may also be present around the depicted pumps 330, 350 and chambers, so that the control system 370 may determine the status of the liquid composition at different points of the homogeniser system. [0135] As mentioned, it is noted that the control system 370 may comprise a memory containing know parameter values, and known spectroscopy results for reactions, reactants and products 390, which the control system 370 may use for comparison during the method described above. In some cases, the user may instead manually enter desired parameters and threshold based on the specific desired reaction. It is also noted that the control system 370 may store within the memory a list of previously used parameters and analysis results so that the control system 370 may determine the best parameters and thresholds to use in order to achieve highest yield for the desired reaction. This way the control system 370 can keep a database of recommended values and dynamically corrected thresholds in order to maximise the efficiency of the homogeniser, by producing a higher yield of the desired product 390.

[0136] The control system 370 may be incorporated into different homogeniser systems. Wherein the control system 370 can be configured to monitor a homogenisation process, through measurements of key parameters of the liquid to be processed at different stages of said process. The control system 370 may be further configured to use the gather data to dynamically adjust the parameters of the homogenising system to adjust the values of the liquid parameters, thereby increase the likelihood of a successful reaction, in turn improving the yield of the device. This system may also allow a single homogeniser system to be reconfigure for different types of liquid compositions. This can allow a single homogeniser to be used to produce a wide range of products, as the system can be easily reconfigured to meet the requirements of different reactant materials.

[0137] The following items are among the embodiments provided in the present description:

1 . An impact head configured to be used within a homogeniser, wherein the impact head has a geometry for improving the efficiency of the homogenization process, and reduce wear on the impact head, wherein the impact head comprises one of a rolling impact head or a stepped impact head; wherein the rolling impact head comprises an impact head design to symmetrically rotate around at least one axis of rotation, wherein the impact head freely rotates; wherein the stepped impact head comprises a plurality of impact heads, or surfaces, arranged into layers, the layers are configured so that the fluid flow 20 impacts the first layer, then runs off the first layer, after which the fluid falls and impact the next layer, and then continuing to flow impacting each other layer of the impact head sequentially. 2. The impact head of item 1 , wherein the impact head comprises a rolling impact head.

3. The impact head of items 1 and 2, wherein the impact head comprises a rolling impact head, and wherein the rolling impact head is configured to be driven by a suitable driving means, wherein the driving means rotate the rolling impact head by a predetermined angle, after a predetermined amount of time.

4. The rolling impact head of item 3, wherein the driving means continuously rotates the rolling impact head.

5. The rolling impact head of any one of items 1 to 4, wherein the rolling impact head comprising a housing and a spherical impact head.

6. The rolling impact head of items 1 to 4, wherein the rolling impact head comprising a housing and an elliptical impact head, wherein the elliptical impact head is configured to rotate within the housing in a specific direction.

7. The rolling impact head of items 1 to 4 wherein the rolling impact head comprising a cylindrical impact head and at least one of a support structure, or a housing, wherein the cylindrical impact head is held in place by the support structure, or housing, and wherein the cylindrical impact head is free to rotate along its longitudinal axis.

8. The rolling impact head of items 3 to 7, wherein the rolling impact head is driven by an electric motor.

9. The rolling impact head of any one of items 1 to 8, wherein the rolling impact head is partially surround by a cowl, configured to form a channel between the rolling impact head and the housing.

10. The impact heads of any one of items 1 to 9, wherein the surface of the impact head includes frictional features, such as grooves, dents or dimples.

11 . The impact head of item 1 wherein the impact head comprises one or more flat impact heads, wherein the impact surface of the flat impact heads comprises a plurality of embedded rolling impact heads, comprising the rolling impact heads of any one of items 2 to 10.

12. The impact head of item 1 , wherein the impact head comprises a stepped impact head. 13. The impact head of item 12, wherein the stepped impact head (90) further comprises channels on the edge of each layer configured to direct the fluid from one layer of the impact head to the next layer of the impact head.

14. The impact head of items 12 or 13, wherein each layer of the stepped impact head further includes one or more embedded rolling impact heads of items 2 to 10, within each impact surface of the stepped impact head.

15. the impact head of item 12 to 14, wherein each layer of the stepped impact head further includes one or more embedded rolling impact heads of items 2 to 10, along the edge of each layer of the impact head, configured to direct the fluid from one layer of the impact head to the next layer of the impact head, or into the channels between layer of the stepped impact head.

16. The impact head of item 12, wherein each layer of the impact head comprises one or more rolling impact heads of any one of items 2 to 10, arranged into layers.

17. The impact head of item 12, wherein each layer of the impact head comprises one or more of the flat impact heads of item 11.

18. The impact head of any one of items 1 to 17, wherein the impact head is movable laterally in a direction perpendicular to the direction of the fluid flow.

19. A homogeniser comprising the impact head as defined in any one of items 1 to 18.

20. A method of manufacturing graphene, comprising treating a mixture of suspended graphene in the homogeniser as defined in item 19, to form graphene.

21. A homogeniser, comprising: an impact head; and a housing surrounding the impact head, so as to form a gap between the impact head and the housing, through which a fluid can flow, wherein the impact head is a sloped impact head having a sloped geometry.

22. The homogeniser of item 21 , wherein the sloped impact head has a sloped geometry comprising one of the following: conical, pyramidal, frustro-conical, or frustro-pyramidal geometry. 23. The homogeniser of items 21 and 22, wherein the impact head further comprises a pneumatic mechanism configured to move the impact head within the housing.

24. The homogeniser of any one of items 21 to 23, wherein the housing comprises one or more sloped housing walls, so as to form a sloped space in which the impact head is placed.

25. the homogeniser of item 24, wherein the sloped space formed by the sloped housing walls has one of a conical, a pyramidal, a frustro-conical, or a frustro-pyramidal geometry.

26. the homogeniser of items 21 to 25, wherein the sides of the housing walls and the slopped sides of the impact head are non-parallel.

27. The homogeniser of any one of items 21 to 26, wherein the impact head is configured to rotate within the housing.

28. The homogeniser of item 27, wherein the impact head is configured to rotate freely, or to be driven to rotate at specific intervals, or both.

29. The homogeniser of any one of items 21 to 28, wherein the impact head comprises at least one flat impact surface.

30. The homogeniser of any one of items 21 to 29, wherein the impact head, and/or housing walls are formed from a tough material, or comprises a protective layer over their impact surfaces, that comprises either a layer placed over the impact surface, or small particles embedded within the impact surface.

31. The homogeniser of item 30, wherein the tough material comprises at least one of tungsten carbide, zirconia, silicon nitride, alumina silicon carbide, boron nitride and diamond.

32. The homogeniser of any one of items 21 to 31 , wherein the homogeniser is configured to produce graphene, graphene nanoplates (GNP), or similar atomic scale materials, by the delamination of a bulk material.

33. The homogeniser of item 32, wherein the atomic scale material, comprises a laminar material. 34. The homogeniser of item 32 or 33, wherein the bulk material comprises solid particles of at least one of graphite, hexagonal boron nitride or molybdenum disulphide, or an aqueous suspension of graphite.

35. A method for using the homogeniser of any one of items 21 to 34, wherein the homogeniser receives a fluid from a fluid source;

The flow of the received fluid is directed towards the impact surface of the impact head;

After impacting the impact head, the fluid flows over the impact head towards the walls of the housing, wherein the fluid impacts the housing walls;

The fluid then flows into a gap between the impact head and the housing to exit the homogeniser.

36. The method of item 35, wherein the impact head may be moved via a pneumatic system, to widen or narrow the gap between the impact head and the housing.

37. the method of item 35 or 36, wherein the impact head is movable closer to, or further from the fluid source, to alter the force generated when the fluid impacts upon the impact surface.

38. The method of any one of items 35 to 37, wherein on determining that the gap between the impact head and the housing is blocked, or partially blocked, the pneumatic system can move the impact head in a manner to widen the gap and allow the blockage to pass through the homogeniser.

39. The method of any one of items 35 to 38, wherein the pneumatic system moves the impact head to narrow the gap between the impact head and the housing, to increase the shear force applied to fluid flowing through the gap.

40. The method of any one of items 35 to 39, wherein some or all of the fluid exiting the homogeniser, flows back to the fluid source to re-enter the homogeniser; and on determining the fluid is re-entering the homogeniser the pneumatic system automatically, moves the impact head to narrow the gap between the impact head and the housing, to increase the shear force applied to fluid flowing through the gap.

41. The method of any one of items 35 to 40, wherein different fluids enter the homogeniser at different times in a process; wherein the pneumatic system automatically adjusts the position of the impact head, to provide a predetermined amount of force to each fluid as it enters the homogeniser.

42. A homogeniser control system for controlling a homogeniser configured to process a liquid composition comprising suspended material for the purposes of reducing the size of that suspended material to provide a finished product, the control system comprising: a processing unit, the processing unit being configured, as regards the liquid composition being processed, to: receive a measure of particle size of suspended material in liquid composition receive a measure of pressure of the liquid composition being processed and can further configured, as regards liquid composition being processed, to control means to adjust one or both of incoming pressure of the liquid processed the gap in the homogeniser impact head primary providing the homogenisation action determined using one or both of the received measures.

43. The control system of item 42, wherein the liquid composition is a suspended solid and the homogeniser is configured to process that solid to submicron dimensions, the particle size being determined by light scattering and/or Raman spectroscopy.

44. The control system of item 43, wherein in the suspended solid is selected from laminar materials capable of delamination, such as graphite.

45. The control system of item 42, wherein when the liquid composition is a suspended liquid in the form of an emulsion and the homogeniser is configured to process that ablation to submicron dimensions, the particle size is determined by light scattering.

46. The control system of item 45, wherein the liquid composition is milk or a milk product. 47. The control system of any one of items 42 to 46, wherein the control means is pneumatic and is configured to move the first part of the homogeniser impact head relative to the second part of the homogeniser impact head so as to thereby adjust the gap in the homogeniser chamber.

48. The control system of any one of items 42 to 47, wherein the measure of pressure of the liquid composition is a measure of the pressure drop between incoming liquid composition and outgoing liquid composition, after passing through the homogeniser chamber.

49. The control system of any one of items 42 to 48, wherein the system further measures temperature of the liquid composition the control means adjustment being further determined using that temperature measurement.

50. The control system of any one of items 42 to 49, wherein the system is configured to recirculate at least a portion of the liquid composition using a diverter, the extent of the diversion being determined by the control system.

51 . The control system of item 10, wherein the system is configured to pass the recirculate through a chiller and the extent of the temperature reduction of the liquid composition being determined by the control system.

52. The control system of any one of items 42 to 51 , wherein the system is configured to pulse the pressure of the liquid composition entering the homogeniser as controlled directly or indirectly by the control system.

53. The control system of item 52, wherein the pulse in in the form of a regular oscillation.

54. The control system of any one of items 42 to 53, wherein the pressure of the liquid for use in the control system is measured in the immediate vicinity, such as the entrance of the homogeniser chamber.

55. The control system of item 54, wherein the pressure of the liquid composition for use in the control system is further measured in the immediate vicinity, such as the exit of the homogeniser chamber.

56. The control system of any one of items 42 to 55, wherein the system is configured to monitor the volume fraction of suspended material in the liquid composition and uses this measure in the control system. 57. The control system of any one of items 42 to 56, wherein the system is configured to monitor the conductivity of the liquid composition and use this measure in the control system.

58. The control system of any one of items 42 to 57, wherein the homogeniser impact head or part thereof is configured to be rotatable in use and the system is configured to measure that rotation and use this measure in the control system.

[0138] It should be noted that the techniques described herein can be used to purify graphite material that include metal sulfide impurities. The purification can be used on several types of graphite materials, such as natural or artificial graphite materials, or on recycled graphite materials from used batteries. Several alternative embodiments and examples have been described and illustrated herein. The embodiments described herein are intended to be exemplary only. A person skilled in the art would appreciate the features of the individual embodiments, and the possible combinations and variations of the components. A person skilled in the art would further appreciate that any of the embodiments could be provided in any combination with the other embodiments disclosed herein. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive. Accordingly, while specific embodiments have been illustrated and described, numerous modifications come to mind.