GB2518816A - Mix Divider - Google Patents

Abstract

An mixer 11 for sample homogenisation comprising a cylindrical rotating tube 14 with first and second sets of helical blades 12 attached to the inner wall of the tube and spiralling from an end of the tube to the tube centre, and two removable end covers 24, 25 at the ends of the tubes 22, 23. The first and second helical blades spiral in opposite directions such that one set can be considered to be right handed and the other set left handed, and a gap exists at the centre of the tube exists between the two sets helical blades. The mixer may be used as a sampler to ensure a representative portion is taken. In use, non homogeneous material 30 is loaded into the tube and the tube rotated in a first direction, such that a blade set will force the material to and hold it at the centre of the tube to homogenize the sample. Rotation is reversed causing the material to travel in opposite directions along the blade sets so that the material is equally split with a portion rejected. Repeated operation allows even reduction the original load material.

Description

Mix Divider This invention relates to sampling such as for evaluation or test of a larger quantity from a smaller sample. In a diverse mix constituents are not necessarily evenly distributed, so taking an arbitrary smaller local sample can be atypical and misleading, albeit inadvertently. Representative scaled-down sampling is challenging. Moreover, samples taken from different locations in a mixed heap or pile may differ in content, with no means of knowing from inspection or otherwise whether there is any better place from which to take a sample.

Ensuring a local sample or smaller portion of non-homogenous material for use and analysis is representative of a bulk mass can be problematic; for some materials more that others. Generally, it is extremely difficult to take a bulk quantity from a source stockpile and reduce it down to a much smaller volume or mass sample test portion, without introducing some error uncertainty however small. A misleading sample and consequent test finding or indication can have adverse consequences for the use to which the bulk quantity is put or the way in which it is handled or treated, such as mixed with other materials.

Term mo logy The term mix' is used herein for convenience to embrace any action of disturbance or agitation, including stirring, turning over, spreading or redistribution; this at whatever stage or condition. The bulk or sample content itself could also be a mix of constituents.

The term divide' or divider' is used herein for convenience to embrace any action of sub-division, fragmentation, re-distribution, separation, severance, splitting or apportionment.

A concomitant proposition is reduction in sample size without loss of homogeneity or representativeness; rather an improvement in homogeneity. In that regard homogeneity can be according to diverse criteria of which physical shape and/or size might be one instance and, say, density, mass or weight another. A reduced size and/or mass sample can have a diversity of individual content, but a distribution which reflects the source from which an initial and representative sample is taken.

One aspect of the invention is to address different densities such as to identify, find, localise or separate out dense and or light particles from a mixed density mass, including a diverse mix in suspension in a common medium, such as water. A parallel might be drawn with gold panning with a wash of water to separate alluvial sand from gold particles.

Prior Art

A common sampling apparatus for test sampling is a so-called Riffle Box', with a series of inclined ramps or down slides, which material is allowed to cascade under gravity, with periodic diversion and extraction. This can prove a laborious and tedious process and one of uncertain or inconsistent outcome.

That aside, screw or augur conveyors or transport mechanisms and other agitators or mixers are known, but generally not for mixed or multi-mode operation, such as that now envisaged with the present invention.

According to one aspect of the invention, a mix divider, sampler and/or sample reduction apparatus, is configured for bringing non-homogenous liquids or solid subject material in a working mix to a homogenous or more homogenous state by subjecting the material to a combination of rotational and linear disturbance, such as through repeated alternating cycles of opposite or reverse directional displacement; the apparatus comprising an elongate rotary confinement chamber, such as a cylinder, a displacement surface within the chamber with a contour or profile to displace material in the chamber in a combined rotary and linear path, such as a helix, to create a repeated piling action, pile or heap formation, alternating with a spacing, spreading or distribution action.

In a practical example, a mix divider is configured firstly to mix a batch of material to homogenise then to sub-divide and separate into substantially equal and homogenous halves, in each of successive operational stages, into progressively smaller proportionate homogenous fractions.

Thus mix divider apparatus can be configured to reduce and separate a batch of material by repeated successive sub-division into a fractional series of two practically equal and homogenous halves, quarters, eighths, sixteenths, and so on.

A mix divider can be scalable by corresponding juxtaposition or positional adjustment of an intervening throat pitch between a working displacement member, such as a helical blade, and a mix chamber housing, such as an elongate cylindrical tube, for a working material or constituent particle or other ingredient batch size.

In a particular construction, a mix divider comprises an elongate confinement chamber, such as a cylindrical tube, for a mixed constituent product, <such as one to be assessed, analysed or used for downstream process purposes,> with longitudinally-spaced, rotationally-opposed, sets (pairs) of internal helical blades, operable whereby rotation of the chamber along with the blades in one direction serves to churn the content together toward a mid-section between and around blades to achieve a more homogeneous or uniform mix; whereas rotation in the opposite direction serves to separate the mixed content into distinct portions associated with each blade at each respective end; a chamber end port with removable closure for content fill and/or discharge, allowing successive alternate rotational reversal cycles progressively to mix, sub-divide and separate into smaller but still more / no less / representative / samples. ccc A multi-stage material sampler and reducer could use in succession a plurality of co-operatively disposed mix divider apparatus, with stages individually scaled to reflect the respective working particle sizes passed through them.

A sampler could have provision to introduce a mix facilitator medium, for improved workability of the mix and in turn to promote representative scaled sampling.

Generally, the apparatus and operation of the present invention combine alternate mixing and (sub-)dividing, splitting and segregation actions to achieve a gradual and evenly scaled-down smaller sample, with characteristics faithfully reflecting or reproducing those of a much larger earlier start quantity, in particular the original batch sampled. Discharge of intermediate stage, (partially-)mixed samples progressively reduces the final sample size. Sample size reduction and ongoing mixing serve co-operatively, constructively and purposefully together. This in turn allows a better or more faithful determination of mix constituent for what ever purpose. That done, wholesale mixing of a larger batch could still be undertaken before use as a whole.

In practice, the mix divider capacity is generally smaller than the total of material to be sampled; thus the first and largest sample to fill the mix divider is likely far smaller than the whole of material from which it is taken.

The first or initial sample must itself be reasonably representative of the larger whole or totality of material from which it is taken. No amount of subsequent mixing and dividing can correct a skewed' initial sample.

After a first sample has been taken from a batch to be tested, there is a need to homogenise, then reduce in scale to a smaller sample, which will be reasonably representative of the first sample before subdivision.

The next sample is smaller as a result of separation by the preceding mixing step which itself is homogenising, as are each subsequent sub-division and separation step.

The objective is even or homogenous sub-division into progressively smaller sample(s).

Representativeness of the homogenous smaller sample is ultimately constrained by that of the initial larger sample. Only if the mix and divide apparatus capacity could accommodate the entire batch to be sampled, could a smaller representative homogenised sample be derived. Thus, operationally the mix and divide apparatus is best placed as far up a material production and/or sampling chain as possible. A representative sample of the load first introduced into the mix and divide apparatus is maintained through ongoing sample size reduction. This in contrast to other known methods relying simply upon random selection, which however good or otherwise are not completely reliable.

The mix and divide actions of the invention also lends itself to wider use, other than merely to preface sample test. Thus even if an absolute test reading, measurement or calculation is not required, a smaller thoroughly mixed sample output is more homogeneous for, say, admixture or combination with other materials in diverse onward or downstream processes.

Mix and divide actions are achievable with complementary, but relatively phased, say reversed, actions or motions, such as rotation, alternative rotation in different directions. A displacement member, such as a curved profile or wound spiral or helical rotary blade, situated within a mix chamber can be employed. A dividing or selective fragmentation mode can be implemented with twin blades, working co-operatively, say in phase and/or in anti-phase.

Thus one aspect of the invention provides a mix (and) divide apparatus comprising an elongate confinement chamber, such as a cylindrical tube, for a mixed constituent product to be assessed, with longitudinally-spaced, rotationally-opposed, sets(pairs) of internal helical blades, operable whereby rotation of the chamber along with the blades in one direction serves to churn the content together toward a mid-section between and around blades to achieve a more homogeneous or uniform mix; whereas rotation in the opposite direction serves to separate the mixed content into distinct portions associated with each blade at each respective end; a chamber end port with removable closure for content fill and/or discharge, say at either one or both ends, allowing successive alternate rotational reversal cycles progressively to mix, sub-divide and separate into smaller but still more representative samples.

The term rotation includes a circular motion, about a fixed point or axis, along with other more complex modes, including elliptical and orbital motions. Correspondingly more complex mix chamber cross-sections can also be used to accommodate such blade motions. The region intervening between a displacement member and the mix chamber can thus vary in quite elaborate ways. This can be used to good effect for mix and divide action.

Having blade pitch in opposition and/or at opposite ends of a containment chamber allows both independent and collective action, in the sense that each blade can independently move or displace material in contact with it longitudinally and radially, either away from the other blade and toward an end chamber wall or selectively opened through port, or toward the other blade to create a localisation or concentration between blades. The blade diameter, orientation and/or pitch + plus speed ** determines the rate at which material is displaced.

A mix chamber tube cross-section with rotational symmetry about a longitudinal rotational axis allows turnover of a mix. Similarly with a displacement and/or mix blade. A circular tube section complements a circular outer blade section, with a blade mounted fast with the inner tube wall. Whilst circular is a convenient simpler form, other tube formats might be adopted, such as conic sections, including ovals or constant breadth shapes, polygonal cross-sections, tapered or cranked forms for particular operational effect. Asymmetrical form, or one with rotational symmetry, tends to achieve an even distributive or separation effect, whereas asymmetric forms could engender content disconformity or displacement localisation. This could serve where the divide function is not simply to split into two equal parts, but to separate a lesser or greater portion from an original whole. Asymmetry could also achieve local more intense mix and differential mix between adjoining mix portions; such as with a material mix of different sized particles.

Additional, segmented or fragmented blades may be employed. Similarly, profiled say serrated or notched, curvilinear or way blade edges may help better bite', grip or engagement with mix particles.

Embodiment There follows a description of some particular embodiments of the invention, by way of example only, with reference to the accompanying diagrammatic and schematic drawings, in which: Figure 1 shows an open end view of Figure 1; Figure 2 shows a side elevation of a mix divider apparatus, with opposed helical blade portions 12 axially aligned within a common cylindrical mix chamber 14, such as a tube, drum or barrel; this serves as a confinement or test chamber, which is initially empty, but which can be loaded, say, by a funnel from one end, or by pressing an open end into a heap from which a sample is to be taken; Figure 3 shows an initial operation stage of the mix divider of Figure I with material loaded in a random distribution within the mix chamber; Figure 4 shows another and subsequent operational stage to Figure 3, with material driven to centre of a mix chamber by rotation of the drum and blades in one direction; Figure 5 shows a later operational stage to Figure 4, with material in mixed distribution having been split and subdivided to opposite ends of the mix chamber,, by rotation of the drum and blades in an opposite direction to that of the preceding mix or agglomeration stage; with one open end the separated content at that end can be discharged to reduce the overall internal sample size; followed by reverse rotation for further mixing to preface a follow-on separation upon another reversal; this can be continued to a target sample size, either by volume or weight; Figures GA and 6B shows performance tables which summarise some example trial data for a common initial sample; Figures 7A and 7B show performance tables which summarise some example trial data for another common initial sample; Generally, the drawings reflect figuratively for simplicity of illustration, rather than literally, the potential disparity of mix constituents. A variant (not shown) could feature serrated or sawtooth blade edge profiles, rather than straight blade edges 17, either following or locally offset from the local curvature plane of the blades, to assist blade and mix engagement, bite' and slicing interaction.

Referring to the drawings, in a particular example construction, a mix and divide apparatus or mix divider 11 of the invention is configured as a rigid outer tube 14, serving as a temporary confinement chamber, fitted internally with a pair of longitudinally offset helical blades of similar format. The throat pitch and depth of the internal blades 12 are of appropriate or complementary dimensions to accept' the anticipated maximum size constituent particles to be processed without jamming.

In practice, as an empirical guide, the gap between any two internal flow path pinch points' is desirably at least 2.5 times the maximum size particle of the mix to be processed. Thus some preliminary assessment of the mix is useful to ensure the mix divider II is suitable and capable.

The inboard ends 19 of serially opposed helical blades 12 are juxtaposed in close proximity in a plane at or about and to opposite sides of the centre of an elongate tubular, in this case cylindrical, confinement and carrier chamber 14. This means that when dividing, a mass of material 30 in the tubular chamber can be split very nearly equally, without intervention, other than simply by reversing the rotation of the tube 14. The blades 12 are rotationally fixed or fast(ened) with the tube 14. This allows a robust construction. Relative rotation of blades 12 and chamber 14 might be adopted if an operational advantage accrues.

s A translucent tube 12 wall portion or local inspection window (not shown) can be filled to monitor internal action and mix state or condition. Operational noise level and/or frequency of mixing may also reflect progress; say becoming calmer of more even with mix homogeneity.

A flow transposition' medium, such as a wetting agent or lubricant intermediary might be introduced to facilitate internal mix movement of constituent particles in relation to one another, in turn for a more rapid, smoother, consistent action. Similarly, or conversely, a binder or coagulant might help bring together, agglomerate or coalesce, for better or more coherent relative working, otherwise disparate, unruly' or free roaming dry fine particulate, granular or powder forms. These measures may also dampen mechanically and quieten operational noise.

Helical blades 12 or rather blade edges and surfaces transition in a combined spiral rotational and linear translational path along and to the centre of the tube 14 from each end; viewed from one end being right-handed and from the other left-handed. This imparts a (longitudinal) translational driving motion or impetus.

Opposed end access ports 22, 23 with respective optional closures 24, 25 at one or both ends allow ready content access for feed and discharge. A single end access port 22,23 may suffice for periodic discharge of the content at that end for progressive reduction in overall sample size within a confinement and mix chamber. Otherwise, the sample size may deplete or degrade too rapidly. Some material retention is useful to preface and preserve an intermediate mix action. End access complements the rotary and linear displacement action of the helical blades 12. Thus a linear transition along the blade 12 axis and a radial fall towards the centre is combined with a rotary or circumferential swirl action. This promotes thorough intermixing towards homogeneity, as reflected in the performance tables of Figures 6A, 6B and 7A, 7B.

Outboard end access, through either one or both end access ports 22, 23, is convenient for loading a sample chamber of tubular format 14. A discrete loading chute or flexible feed conduit (not shown) might be used and/or the tube 14 end thrust into a material pile, with reliance upon a screw augur action of the blades 12 to draw material inward.

Figures 2 through 5 represent successive stages in an operational cycle of blade rotation for bringing together for mixing and reversal for separation of tube chamber 14 content.

When a non-homogeneous batch of material 30 is loaded into the tube 14, and the tube 14 rotated in one direction, the blade helices 12 create a series of travelling individually continuous and collectively contiguous wave ramp surfaces, over and down which material 30 particles can flow radially under gravity, whilst being transposed longitudinally, so effectively will displace or drive the material toward the centre of the tube 12.

After a certain nominal length of time, the non-homogenous material 30 will be redistributed to become more homogenous about the centre of the tube 12, having been constantly dropped into the centre from the opposing ends of the helices. A continuous rotary piling' action is achieved. Thus in one rotational direction later piles are overlaid upon and spill down over earlier piles, which then crumble and decay. In the other rotational direction piles are never built or are continually eroded.

A limit to the ongoing affect will be reached; with further action becoming less productive. The action should not be unduly extreme or vigorous and be compatible with the physical robustness and integrity of the subject material. Otherwise excessive action may start to undermine, wear, degrade and break down the physical integrity of the material into smaller particles. An insidious process which might continue indefinitely with greater departure from the original; thus undermining if not defeating the original intention of a homogeneity and representativeness expressed in a reduced sample. This is an issue of friability or susceptibility to breakdown, or chemical or physical change, which may arise in hard or soft materials when subject to shock impact or continually abraded or ground. The blade surface contour and edge profile have a bearing on this, as a blade bites into material.

When the material 30 has reached its homogenised state, or such as can be achieved in a time scale, and having ensured that ether one or both end port has been closed or covered, the rotation of the tube 14 can be reversed, causing the material 30 to split equally and longitudinally; some one half being forced back to each end by the opposed helical blades 12. Material 30 at an open end 23 of the tube 14 is displaced and lost' (or might be recycled eventually rather than wasted), whilst material 30 at the closed end 22 retained. Rotation of the tube 14 can now be reversed once again, allowing the action to be repeated as above. The sample is captured within the mix chamber and entrained between opposite ends and the intervening opposed pitch blades. In some operational variants, material could be introduced later in the mixing and sub-division to achieve a blend for ongoing homogenisation, sample separation and sample size reduction.

By putting the material 30 through a series of successive such alternating mix and divide actions, it is possible to reduce the original load of material 30 very coherently and representatively and by nominally 50 per cent through each cycle of operation, until the remaining amount in the tube 14 is of a target mass, whereupon an end closure cap 24, 25 can be removed and a target mass of homogenous or rather homogenised material 30 collected through the end port. The initial sample load has a bearing upon the subsequent separated and sub-divided loads.

Figures 6A and 6B present data in table form of different operational tests upon a common sample weight of some 644.5g to asses the proportionate separation and diversity of mix constituents. Thus in the test outcome reflected in Figure 6A the original sample was split or separated into two portions, with a retained portion some 48% of the original or preceding sample. The constituent mix was assessed by passing through sieves with different aperture sizes ranging from 500 microns to 8mm with residue collected in a pan. The percentages by weight of material in each sieved aperture category was found between 4% and 28%. A separate test whose results are presented in Figure 6B gave results consistent with those of Figure 6A with a separation of 52% and a sample range of 4% to 31%.

In further tests with an initial sample weight of some 760g, similar proportionate separations were achieved in separate test runs with results reflected in tables of Figures 7A and 7B. A range of mixed size items, such as nuts, bolts and washers was run and separated with general consistency between the tests. An overall split or separation of around SO% was achieved. Separations of 55.7% and 44.3% were achieved with both sample weights and component counts taken.

Operationally, it may be helpful, if not essential, to cleanse or purge the mix chamber upon emptying to avoid contamination between successive mix. An intermediate mechanical surface scour material, agent or medium could be used for that purpose. A liquid or gel might also be used to dissolve, wash, flush and rinse out the chamber. Overall, the constructional and operational simplicity of the mix and divide apparatus 11 of the invention, not least when compared with other dividers makes it extremely reliable and efficient.

While mixing, the mix and divide apparatus 11 continuously transfers material over and about or around a blade surface, in a blade wiping action, towards an inboard end of each helical blade 12 and drops it toward the axial centre of the tube 14 with each revolution. This is effectively equivalent to repeatedly making a conical heap or pile alternately collapsed over and over again. Each pile disturbance promotes further mixing. A self-priming effect arises and prevails. Through this action the particles in the material are displaced over one another and inevitably sorted and stratified by means of their size, density and angle of repose as they respond to the force of gravity, in a proactive regurgitation'. This compared with the vagaries of random selection employed in most other methods.

A level, or horizontal, straight tube 14 represents a simple elongate linear configuration, with uniformly distributed symmetrical gravity effect on the contents. Nevertheless, other, say, curved, cranked or inclined forms might be adopted for special asymmetric distributive purposes. A see-saw rocking balance mount might also be adopted to allow self-balancing and stabilisation.

An example material category for sampling is aggregates for building and construction, which can be classified by material type, group or particulate shape, size, and range. Although a prime consideration might be to harmonise or unify an otherwise disparate mix, for representative local sampling, separation and onward testing or appraisal, the mix' function or role might be asserted on its own; that would be a mix for any (onward) purpose' agenda.

A helical scroll blade element is also found in other material displacement devices, such as a concrete mixer; for a combination of mix and discharge function of a fixed batch size periodically discharged wholesale by tipping over to one side. Thus the divide' function of opposed, serially or co-operatively aligned blades might be regarded as an essential concomitant of a prefacing mix' action.

Allowing some control of sample size, whilst preserving a homogenous mix, is a challenge, even if the sample size is far larger than that of individual constituents. Diverse other blade profiles, dispositions and enclosure configurations could be adopted. As to the range of constituent particle shapes and/or sizes and so the potential diversity of the mix; empirical trials have shown that the mix and divider 11 of the invention is capable of performing efficiently with very varied particle shapes, as the mix and split or divide functions are essentially driven by the action of gravity. Thus, for example, elongated particles such as bolts in the same batch as platelets such as washers are mixed and divided with excellent results.

The dimensional size and volumetric capacity of the chamber 14 within which the helical screws or augers 12 operate, admit of variation. Similarly for the size, depth, pitch and longitudinal span of the helical blades to change the (sub-)division ratio. The limitations of the mix and divider 11 are only driven by the maximum particle size to be processed; generally, the maximum size to be processed should not be more than 2.5 times less than the smallest pinch point, e.g. the pitch of the blades or the bore of the blades 12; similarly, with the pitch and throw' of the blades 12.

The rate or urgency' of churn' or the mix and the duration or longevity of the action to achieve a desired mix homogeneity. This performance can be assessed through trials. The degree of churn must be at least enough to free the particles from rest, but not so great as to hold them back through centrifugal force.

The prospect of diverse particles in the mix mutual abrading and so undermining representativeness of the original batch would depend on the material 30 being processed but is not foreseen as significant. Noise levels and tonal frequency mix or character are an informal indicator of operation and stage progress. There will be a considerable noise level generated with some particles, but adaptations could easily be made, say, or rubber lining to suppress noise. The addition of an intermediary mix facilitator will tend to modulate and dampen the noise. Provision could be made to bleed or drain off excess lubricant liquid.

The mix (and)divide proposition can be made to work damp, moist, wet or dry. It would also be relevant to a slurry of mixed particulate solids in a suspension or solution. A dimensional range of construction particles of immediate interest could usefully be specified; along with a projection of a bounding range of maximum and minimum particle sizes. Certain shapes or particle proportions, such as say long thin rods, simply would not lend themselves to sorting, but would risk jamming, in a diverse mix, such as ball bearings. Resolving this could be just a matter of selecting blade and chamber dimensions to suit the load. An adjustable' apparatus might be configured, such as with movable blade or tube wall portions.

A variable blade rotational rate contributes to sorting efficacy; such as a slow initial blade 12 rotation, progressively increased as the mix 30 frees-up'. A variable blade 12 diameter pitch could contribute to performance, such as a tapered or waisted blade 12 within a complementary tapered or waisted chamber.

Differential density sorting can be achieved with blade configuration. Depending upon their configuration, helical auger blade rotary action could also serve to blend or separate liquids (such as water) from solids; or simply make all particles in a mix (uniformly) wetted'. Auger operation could help dry out' a wet sample by a continuous surface wipe action, breaking down surface tension of any moisture.

Helical blade edges could be profiled (e.g. notched or serrated) to any useful interaction with a particle mix, for re-distributive or selective (biassed) effect. A prototype blade 18 with serrations and may help to lift and or drag the particles up and around the blade 18 as it rotates; making it easier to achieve the falling off the end of the blade effect.

A variant of the basic mix divide apparatus could have a wider investigative role; such as to prioritise or bring out a particular range of particle sizes; such as a grading rather than unifying a outcome; subject to some analysis. An alternative sort andlor separation mode would be for particles of the same or similar size, but of different densities, which could also tend to average and/or homogenise densities.

In an operational version of the device, there is scope for an inspection window 15 in the chamber wall or a translucent body; although trial and error would quickly provide the information needed to choose a correct operating speed.

There is an option to flush out the mix chamber 14 between runs on different mixes; particularly, if cross-contamination between samples is an issue, in some circumstances; as with other classifying equipment which generally use an inert load, like glass particles to clean the surfaces.

Supplementary fill of the mix chamber with, say, water could achieve a faster or more efficient mix and divide action; subject to empirical trial; the simplest formats offer great efficiency, but more elaborate variants could be contemplated.

Although a level mix chamber 14 would offer symmetry; selective variable tilt or periodic rocking' tilt reversal could engender faster cycle time before sampling. Tilt could make the downward blade work uphill', at a steeper effective helical ramp angle, with implications for the churn rate. There would be a temporary gain of more intense local activity burst at one end, with a temporary loss or rather less intense mix activity at the other; which could be beneficial for local disordered pockets. At worst, as the gain and loss ends reverse, there would be an even net effect.

Albeit of less general purpose utility than a simpler format, the mix chamber 14 could be split, say, into independent aligned sections or segments for each blade, allowing differential blade rotation and mix interaction. Discrete blade segments, blade carrier and mix chamber could follow a linear or even curvilinear path. Again in still more elaborate variants, a linear reciprocating shuttle mode could be deployed to accelerate blade action.

Mix chamber 14 conditioning, such as temperature, could be considered; this would be significant with some materials, such as those whose flow behaviour or viscosity reduces with elevated temperature.

Similarly with humidity conditioning or, say, aeration.

The limitations in particle diversity, can be explored by trials experience, starting with some assumption(s) followed by extrapolation. An example of diversity of particle type and form would be washers, screws, bolts, other fasteners. A limit to overall mix and divide operation time; such as the number of blade reversals and time between successive discharge to reduce the sample size, beyond which no further significant gain is sample consistency is achievable; will depend entirely on the nature of the medium being mixed and divided If a large sample is required, say occupying the entire capacity of a mix chamber, mix rotation could simply continue longer, without intermediate divide and discharge; subject to trials to determine a maximum ratio of sample volume to mix divider volume. Achievable sample uniformity may be a factor of sample size; that is the number or reductions followed by further disruption or churn'. Generally, the more (sub) divisions that are made, the less accurate or rather representative a sample itself will be -simply because the sample' would be smaller. Apparatus features need not limit representative sample reduction homogeneity performance. Thus it may be that the blades will work better if they have a rough surface or even stepped and possibly with an outer skirt along the blades length as found in a concrete mixer.

A mixed liquid could be achievable, whether the liquids are immiscible, dissolved mutually or suspended in a shared carrier solution or other flowable low viscosity medium. Mixed solids do not have to be immiscible for mix and divide separation to work. Thus constituents might merge or blend seamlessly. The aim is to provide evenly distributed medium in both (equalised) sample portions or halves, without attempting to separate the particles of the medium from one another. Scalability, up or down, is achievable, as the common action and effect is that of gravity. Material type is relevant to mix and divide action and thus to wider industrial application; put simply, some materials will work', or rather be (internally) workable, faster than others.

Diverse other admixtures, and intermediary media, such as with super plasticisers, could be used for improved workability. An intermediate, severable or isolatable, neutral' additive social' medium of appropriate shape and/or size diversity could be introduced as a facilitator or enabler for material internal mobility and constituent transition, rather like a lubricator, to promote homogeneity. Liquids aside, the additive could be a solid particulate or powder form. Agas intermediary might also work, say if applied under pressure to engender pocket bubbles.

The otherwise distorting contributory' effect (upon content) of an additive or intermediary factor could be discounted upon suspension or conclusion of primary mix and divide operation for homogeneity and consistency. For specialist purposed, mix distortion or bias could be introduced deliberately, say to favour particles with certain selected characteristics.

Load sensing, with an overload cut-out, may be fifed to the displacement drive to monitor the mix and divide process and to avoid excessive material degradation. A burst relief limiter, bleed or drain, say in the form of a preset valve, might be lifted to the mix chamber to avoid excess working load and material stressing, particularly with liquid in the mix; although an objective is to preserve ample free space around the material being worked. A compressible intermediary transposition' medium, such as a an aerated foam gel or slurry, might also be introduced to absorb and cushion sudden internal shock load or build up. The material working rationale is displacement rather than compression; which requires a certain inherent material mobility or viscosity. That is the material readily moves out of the way of a displacement member such as a blade when pressed or pushed. Some of these considerations are relevant to wider downstream industrial processes.

Visual appeal or entrancement of mixing and separation action may lend itself to an executive toy or game variant. A challenge of admitting ad hoc sample variation and control to achieve greater diversity of constituent toward a certain mix or division challenge may also be imported.

The device lends itself to sensing through say blade rotational count, blade displacement or bending, torque loading and optical scan of content distribution, sample weighing, along with the option of remote control of outlet ports. Aside from assorted particle size, mass or density, shape and colour diversity are also variable factors for greater continually changing visual effect, rather in the manner of fractals. A variable tone and volume audible accompaniment could also be contrived for sonorous or musical effect. A combination of optical and aural effect could provide a subliminal performance measure useful in an industrial context.

A facility for blade positional, pitch or twist and/or profile adjustment and remote control could link with remote sensing to help optimise performance.

Blade edge profile admits of considerable variation, including combination or alternating straights and serrations, following the general helical surface curvature. Blade rotation with the containment tube is featured in the example, but relative blade and tube rotation might be contemplated with some working clearance. For simplicity a dual portion blade is used, but more elaborate subdivided blade forms might be adopted. Similarly with more complex blade rotational modes to achieve certain content re-disposition within the sample chamber.

Component List II mix divider 12 displacement member! (helical) blade 13 end port 14 mix chamber inspection window 17 blade edge (straight or serrated) 22 end access port or closure 23 end access port or closure 24 closure closure material! materiel'