cutter

Abstract

A cutter for diverting a sample flow from a process flow has an upstream end and a downstream end, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end, the cutter has an elongate body having a longitudinal axis and adapted to extend longitudinally across the direction of process flow, the elongate body including a leading edge and lateral walls positioned, in use, at an oblique angle to the direction of process flow with the walls diverging away from each other from the leading edge, at least one of the lateral walls including a series of longitudinally spaced openings proximal to the leading edge, the openings being configured to receive the sample flow.

Description

[0001] CUTTER

[0002] TECHNICAL FIELD

[0003] A cutter is disclosed for diverting a portion or "cut" of a process flow (such as from a pipeline of a mineral processing plant). The cutter may be used in a sampling system for collecting a sample flow from a mineral processing pipeline, for example, as a first stage of the sampling process. Also disclosed is a cutter assembly that includes the cutter. Further disclosed is a sampler that includes the cutter assembly. Further disclosed is a process for taking a sample flow from a process flow using the cutter of the present disclosure.

[0004] BACKGROUND ART

[0005] A sampler, or sampling system, is a device or combination of devices designed to collect a portion of a material flow suitable for analysis. In the context of liquids, slurries, or suspensions, it is crucial to ensure that the sample accurately reflects the composition of the bulk flow, aiding process control and decision-making. The cutter is the key component of samplers or sampling systems responsible for splitting the main process flow into a smaller 'sample flow'. The cutter tends to be used in the first stage of sampling (primary samplers). Further stages (secondary or tertiary stages / samplers) may involve the further transport, reduction or splitting of the sample flow until its final analysis by an online analyser, or an analytical laboratory. Since errors in sampling in the primary stage carry forward to the secondary and tertiary stages, the reliable operation of the cutter is critical to maintaining sample quality.

[0006] Samplers are commonly used in mineral processing pipelines and discussion herein will focus on that application, although it is to be understood that the present disclosure is not limited to that application. The resulting samples diverted by the cutter typically comprise a slurry of particulate matter (such as partially or fully leached ore or concentrate) suspended in an aqueous solution (such as an intermediate leach solution (ILS) or pregnant leach solution (PLS)).

[0007] The assays resulting from the analysis of such samplers are often the basis for mineral processing plant control and optimisation and are typically required to provide samples for online analysers.

[0008] Existing cutters are often detachable for replacement and generally located within a sampler housing extending vertically across the process flow when installed. Such cutters typically have a generally elongate configuration with an opening or multiple openings on its upstream face. Therefore, eitherthe single opening is elongated across the flow, or multiple openings are spaced vertically across the flow to receive a sample flow from the process flow. The purpose of the cutter is to receive sample across the vertical cross-section of the pipe from multiple points in the flow to improve the representativity of the resulting sample flow. However, it has been found that in practice such cutters are generally not suitable for applications having one or more of the following features:

[0009] • Large particles in suspension,

[0010] • Slurries with high wearing solid material in suspension such as chromite, or

[0011] • High flow rates

[0012] due to unacceptably high wear rates and susceptibility to blockages. While wear and blockages are a major issue in themselves, they are also problematic due to the concomitant downtime on any downstream equipment (such as a slurry analyser) processing the diverted stream. Even a partial blockage is problematic, at least to the extent that it reduces representativity of the sample flow.

[0013] There is accordingly a need for a sampler, and cutter for use therein, which overcomes, or at least alleviates, one or more disadvantages of the prior art. There is a further need for a cutter, for use in a sampler, that enables the diversion of a sample flow that is representative of the process flow.

[0014] The above references to the background art do not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art. The above references are also not intended to limit the application of the apparatus and method as disclosed herein.

[0015] SUMMARY OF THE DISCLOSURE

[0016] In a first aspect, there is provided a cutter for diverting a sample flow from a process flow, the cutter having an upstream end and a downstream end, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end, the cutter having:

[0017] an elongate body having a longitudinal axis and adapted to extend longitudinally across the direction of process flow,

[0018] the elongate body including a leading edge and lateral walls positioned, in use, at an oblique angle to the direction of process flow with the walls diverging away from each other from the leading edge,

[0019] at least one of the lateral walls including a series of longitudinally spaced openings proximal to the leading edge, the openings being configured to receive the sample flow.In a second aspect, there is provided a cutter assembly for use in the collection of a sample flow from a process flow, the cutter assembly including:

[0020] a housing insertable in a mineral processing pipeline and having an upstream end and a downstream end, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end; and

[0021] a cutter locatable within the housing between the upstream end and the downstream end, the cutter having:

[0022] an elongate body having a longitudinal axis and adapted to extend longitudinally across the direction of process flow,

[0023] the elongate body including a leading edge and lateral walls positioned at an oblique angle to the direction of process flow with the walls diverging away from each other from the leading edge,

[0024] at least one lateral wall including a series of axially spaced openings therethrough, the openings being configured to receive the sample flow.

[0025] In an embodiment of the second aspect, the cutter is removable from the housing. The cutter may advantageously be attached to the housing by fasteners. The cutter may be insertable via a port. The cutter may be removable from the housing without requiring the housing to be replaced in its entirety, (such as if the cutter and housing were manufactured as a singular part).

[0026] In a third aspect, there is provided a sampler for diverting a sample flow from a process flow, the sampler including:

[0027] a cutter assembly as described above, and

[0028] a sample conduit in fluid communication with the cutter and for passing the sample flow therethrough after it leaves the cutter.

[0029] Accordingly, the cutter serves as a conduit for the diverted sample flow. The cutter is orientated so that it extends longitudinally across the direction of process flow. This orientation allows the cutter to be exposed to a representative cross-section of the process flow. For example, in the case of a horizontal mineral processing pipeline, where gravity causes downward settlement of particulate solids in the slurry, and is the only acting force of notable effect, the cutter is advantageously oriented substantially vertically. In this orientation, the cutter is generally aligned with the direction of settlement (and oriented radially relative to the cross-section of process flow). The cutter istherefore able to be exposed to, and therefore divert, a representative sample of the process slurry, particularly where the slurry has settled into settlement layers.

[0030] The cutter assembly includes the cutter described above and a housing insertable in a mineral processing pipeline. The housing has an upstream end and a downstream end, such that in use, the process flow travels generally in a direction from the upstream end to the downstream end. The housing is able to hold a cutter securely in the process flow of the mineral processing pipeline. The housing may be attached (such as by bolting) to the main mineral processing pipeline, thereby enabling the process flow to flow through the housing without leakage (except for the diverted sample flow). In one embodiment, the diverted sample is subsequently returned to the cutter assembly and reintroduced into the process flow stream, at a position preventing recirculation of the sample flow, for example, by a port and sample conduit located on top of the housing but downstream of the cutter.

[0031] The housing may advantageously comprise a similar material and shape to the mineral processing pipeline into which it is inserted for seamless flow transfer if no induced turbulence is required. For example, the housing may be constructed from metal (eg, steel) and have a cylindrical shape.

[0032] However, any material or shape that successfully houses the cutter and achieves the functionality described herein is considered suitable. The material of the housing need not necessarily be metallic, and its shape need not necessarily be cylindrical.

[0033] In a fourth aspect, there is provided a method of diverting a sample flow from a process flow in a mineral processing pipeline using the cutter described above, the pipeline having an upstream end and a downstream end and, in use, the process flow travels generally in a direction from the upstream end to the downstream end, the method including:

[0034] positioning the cutter within the pipeline such that the elongate body of the cutter extends longitudinally across the direction of process flow, the leading edge of the cutter faces upstream and the lateral walls of the cutter are at an oblique angle to the direction of process flow,

[0035] causing the process flow to travel from the upstream end towards the downstream end of the pipeline, and

[0036] diverting a representative sample of the process flow into the longitudinally spaced openings proximal the leading edge of the cutter.

[0037] In one embodiment, the process flow may be a solids-containing slurry. For example, the process flow may comprise a slurry of at least partially leached ore minerals suspended in an aqueousprocess solution (eg, a pregnant leach solution (PLS)). Advantageously, the sample flow can travel through the sampler while maintaining resilience to blockages and wear.

[0038] The present inventor has recognised that wear of a cutter is related to the energy of impact of particles in the process flow and that minimizing the surface area of the cutter that faces the process flow at right angles, minimizes the wear of the cutter. For a constant impact energy, the attack angle reduces wear by sine (angle of attack - the angle between the lateral housing wall and the flow direction). Relocation of the openings from the front of the cutter (such as from a front edge or wall of the cutter) to the side of the cutter, enables the application of wear resistant materials to this area while making the openings less susceptible to blockages. The cutter wear may be additionally minimized by including a wear-resistant lining material, surface treatment or coating on the cutter that is exposed to the process flow. Suitable materials that may be used for the wear-resistant surface include rubber, polymer-based coatings such as PTFE, epoxy-based materials, PPS, ETFE polyurethanes. Other types of wear resistant coatings include thermal spray coatings and tungsten carbide coatings.

[0039] Accordingly, the disclosed cutter includes an elongate body including a leading edge and lateral walls diverging away from each other from the leading edge. The leading edge may be angled or rounded. The diverging lateral walls and leading edge together form a flow-facing side of the cutter. In at least one lateral diverging wall there are multiple openings therethrough that are spaced longitudinally along the elongate body, with the openings being configured to receive the sample flow.

[0040] Due to the relocation of openings from the flow-facing side of the cutter (as typical in the prior art) to the lateral walls, the high wear typical of the prior art flow-facing side can be addressed by shaping and / or reinforcing the leading edge of the present cutter as appropriate for each application. In low wear applications, the leading edge may be angular or sharp and no lining or coating of the leading edge may be necessary. However, in high wear applications, single or multiple liner / coating layers and / or appropriate radiusing (rounding) or shaping of the leading edge may be appropriate to minimize wear.

[0041] Aside from the flow-facing side of the cutter, the geometry of the remainder of the cutter may comprise a primarily structural support function. It advantageously may prevent further mixing of the sample flow with the process flow after the cut is achieved. However, in an embodiment, the cutter may further include respective converging lateral walls that extend between the diverging lateral walls and the trailing edge. The converging lateral walls and trailing edge together form a leeward side of the cutter.In a further embodiment, the cutter may have a generally rhomboid shaped cross section. The opposed acute angles of the rhombus are defined by the respective leading edge and trailing edge of the cutter. The leading edge is defined by the diverging lateral walls. The opposed obtuse angles of the rhombus may each be defined by a respective pair of diverging and converging lateral walls that meet at opposing lateral edges of the cutter.

[0042] The lateral walls may be constructed from any suitable loadbearing material such as stainless steel. The walls may additionally be lined or coated with one or more outer wear-resistant and / or impactresistant layers. Each layer may comprise the same or different materials having suitable properties. In an embodiment, the liner or coating is continuous around the leading edge of the cutter such that there are no seams or other areas of weakness that are exposed to oncoming slurry, abrasion and impact damage. The liner is designed with openings corresponding to the openings in the lateral walls of the cutter such that when the liner is applied to the structural lateral walls, the slurry may pass freely into the cutter.

[0043] The cutter includes longitudinally spaced openings proximal to the leading edge. The longitudinally spaced openings may advantageously extend across the maximal cross-sectional extent of the process flow such that they are exposed to, and can divert, a representative cross-section of the process flow. The openings may advantageously have an elongate configuration. The longitudinal axes of the openings may extend generally in the direction of process flow. Each opening may additionally be tapered along the longitudinal axis such that it becomes gradually wider from the upstream end towards the downstream end thereof. In this manner, there is minimal blocking of the openings by the particles as they traverse across the flow-facing side of the cutter in the slurry flow direction. In an embodiment, the opening / s may be any shape, number, and in any position, provided that there is a gradual and consistent widening of the opening from the upstream towards the downstream end. There may be a narrowing of the opening at the downstream end thereof. A suitable opening configuration is "kite-shaped", (or in other words, an orthodiagonal quadrilateral). Such openings therefore include acute and obtuse angles. The openings are preferably oriented such that the acute angle of each opening is positioned proximal the leading edge side of the cutter, where the process flow first contacts the opening. The obtuse angles of the kite-shaped openings are located on the leeward side of the opening's vertex, within the low-pressure zone of the cutter. The ratio of the largest width to the smallest width of the openings depends on the 'sharpness' of the openings on the upstream side. Assuming that the smallest width of the openings is approximately 1 mm, the ratio of the largest width to the smallest width of the openings may be atleast 1:1, such as from 1.66:1. In another embodiment, the ratio of the largest width to the smallest width of the openings may be at least 1.75:1. In another embodiment, the ratio of the largest width to the smallest width of the openings may be from 2:1. In another embodiment, the ratio of the largest width to the smallest width of the openings may be from 2.5:1. In another embodiment, the ratio of the largest width to the smallest width of the openings may be from 3:1. In another embodiment, the ratio of the largest width to the smallest width of the openings may be from 3.5:1. In another embodiment, the ratio of the largest width to the smallest width of the openings may be from 4:1.

[0044] In another embodiment, the ratio of the largest width to the smallest width of the openings may be a maximum of 10:1. In another embodiment, the ratio may be a maximum of 5:1. In a further embodiment, the maximum ratio may be 7:1.

[0045] Under circumstances where manufacturing methods permit the upstream side of the opening (ie, the smallest width) to be close to or substantially zero (eg, via laser cutting), the ratio of the largest width to the smallest width of the openings may be higher than 10:1. The ratio may for example be 1000:1 or greater.

[0046] In one embodiment, the openings are also spaced downstream from the leading edge of the cutter. By locating the openings away from the leading edge the applicant has surprisingly discovered that there is less likelihood of the openings becoming blocked. Considering that the particle size range useful for sampling and subsequent laboratory analysis fall in a normal distribution, large particles which fall outside this distribution and are unwanted are generally an order of magnitude larger. For example a typical size range in mineral slurries is 20-120 pm particles, in which case, particles in the mm size ranges are generally few, and can be accordingly removed without affecting the assay result. Therefore large particles (such as 1mm and larger) which might otherwise cause blockages or impact and wear damage, do not directly impact the openings in a head-on collision (ie, a collision at right angles). Instead, they are presented with a relatively narrow contact surface (the leading edge of the cutter), and if not deflected entirely, have a tendency to adopt a rolling momentum. On the other hand, smaller particles of interest (for example, in the order of less than 1mm in size) have a significantly smaller moment of inertia and are therefore not similarly affected and separated.. Moreover, the location of the openings on the oblique lateral wall / s of the cutter further assist in reducing blockage of the openings. This is enhanced where the openings terminate on the leeward side of the cutter, where a low pressure is created by the passing slurry. Additionally, the termination of the openings on the leeward side allows for some small percentage of the slurry to enter and leave the cutter, providing a flushing effect.In one embodiment, the openings may be also elongated on the leeward side to achieve symmetry of the openings about the longitudinal axis of the cutter. This allows the cutter to be rotated by 180 degrees about its longitudinal axis, allowing the user to potentially expose the less worn leeward side to oncoming flow, and thereby extending the overall service life of the cutter.

[0047] The cutter may further include internal baffles or similar structures. The baffles may be arranged at an oblique angle to the direction of process flow. The baffles assist in preventing or redirecting elongated particles from entering the cutter and causing downstream blockages. The oblique orientation of the baffles further optimizes the geometry of the openings and minimises surfaces perpendicular to oncoming slurry flow, and thereby minimizes cutter wear.

[0048] In an embodiment, the cutter is part of a cutter assembly. The cutter assembly includes the cutter described above and a housing that is insertable in a mineral processing pipeline. The cutter may be inserted and removed from the cutter housing from the top and bolted in place. The cutter may include one or more flanges by which the cutter may be secured to the housing, such as by bolts. Advantages of the sampler and cutter of the present disclosure may include the following:

[0049] • Reduced wear rate of the cutter and corresponding reduced maintenance costs.

[0050] • Reduction of blockages in the cutter (improving sampling representativity) and downstream equipment.

[0051] • Reduced down-time of the equipment used for analysing the samples taken from the process flow.

[0052] BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Notwithstanding any other forms which may fall within the scope of the present disclosure as set forth in the claims, specific embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:

[0054] Figure 1 is a perspective view of a prior art process flow sampler including a prior art removable cutter (shown in phantom).

[0055] Figure 2 is a front view of a prior art cutter of the type shown in Figure 1.

[0056] Figure 3(a) is a perspective view of an embodiment of a cutter as herein disclosed.

[0057] Figure 3(b) is a side view of the cutter embodiment shown in Figure 3(a).

[0058] Figure 3(c) is cross-section A-A from Figure 3(b).Figure 3(d) is a view of detail B of Figure 3(c).

[0059] Figure 3(e) shows detail of one of the openings in Figure 3(b).

[0060] Figure 3(f) shows an alternative embodiment of the cross- section A-A of Figure 3(c).

[0061] Figure 4 (I) and (II) are perspective views of the prior art cutter of Figures 1 and 1, showing wear after use.

[0062] Figure 4 (III) and (IV) are perspective views of the cutter of Figures 3(a) to (f) showing wear after use.

[0063] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0064] Reference will now be made in detail to preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

[0065] Accordingly, the accompanying drawings show a cutter for diverting a sample flow from a process flow. The cutter has an upstream end and a downstream end, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end. The cutter has an elongate body having a longitudinal axis and which is adapted to extend longitudinally across the direction of process flow. The elongate body includes a leading edge and lateral walls positioned, in use, at an oblique angle to the direction of process flow, with the walls diverging away from each other from the leading edge. At least one of the lateral walls includes a series of longitudinally spaced openings proximal to the leading edge, with the openings being configured to receive the sample flow.

[0066] Figure 1 is a perspective view of a prior art process flow sampler 10 including a cutter assembly 20 that includes a removable cutter 30 (shown in phantom). The cutter assembly 20 includes a housing 40 comprising a pipe that is insertable into a mineral processing pipeline (not shown). The housing 40 is able to hold a cutter 30 securely in the process flow of the mineral processing pipeline. The housing 40 has an upstream end 50 and a downstream end 60, wherein in use, the process flow travels generally in a direction indicated by arrow Fl from the upstream end 50 to the downstream end 60. The housing 40 is attached to the main mineral processing pipeline, thereby enabling the process flow to flow through the housing without leakage (except for the diverted sample flow). Each respective end of the housing 40 includes a circumferential flange 70a, 70b having apertures 80 therethrough for connection to a respective corresponding flange on sections of the mineral processing pipeline (again, not shown) using suitable connectors, such as bolts and nuts. The cutterassembly 20 further includes a sample conduit 90 in fluid communication with the cutter 30 and for passing a sample flow therethrough after it leaves the cutter.

[0067] The housing 40 advantageously comprises a similar material and shape to the mineral processing pipeline into which it is inserted for seamless flow transfer if no induced turbulence is required. For example, the housing 40 may be constructed from metal (eg, steel) and have a cylindrical shape. However, any material or shape that successfully houses a cutter and achieves the functionality described herein is considered suitable. The material of the housing need not necessarily be metallic, and its shape need not necessarily be cylindrical.

[0068] Figure 2 is a front view of a prior art cutter 30 of the type shown in Figure 1 after removal from the cutter assembly 20. The cutter 30 includes an elongate body 31 having a longitudinal axis X-X (shown in Figure 2) and adapted to extend longitudinally across the direction of process flow Fl (see Figure 1). The elongate body 31 includes a leading edge 32 (see Figure 1) along which are located longitudinally spaced openings 33 for receiving the sample flow. The prior art cutter 30 further includes a mounting flange 34 at the upper end thereof and a support flange 35 at the lower end thereof. As shown in Figure 1, housing 40 has an upper port 44 and lower port 46 surrounding respective apertures into the housing 10. The lower port 46 is connected to the sample conduit 90. The upper port 44 has an upper mounting collar flange 45. In use, cutter 30 is inserted through upper port 44 to a position where mounting flange 34 abuts the upper mounting collar flange 45. The flanges 34 / 45 are then attached by means of fasteners comprising bolts 42. In this position, the support flange 35 is tightly seated within lower port 46 so that does not have to be separately attached to the housing 10.

[0069] Figures 3(a) to (f) show views of a cutter 130 as herein disclosed that is suitable for insertion e into a housing 10 of a cutter assembly 20 of the type described above. Referring to Figure 3(a), there is shown a cutter 130 for diverting a sample flow from a process flow having a direction of flow indicated generally by arrow Fl. The cutter 130 has an upstream end 130a and a downstream end 130b, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end. The cutter 130 includes an elongate body 131 having a longitudinal axis X-X (shown in Figure 3(b)) and adapted to extend longitudinally across the direction of process flow Fl. The cutter 130 further includes a mounting flange 134 at the upper end thereof and a support flange 135 at the lower end thereof. The mounting flange 134 and support flange 135 perform the same functions as the mounting flange 34 and support flange 35 of the prior art cutter 30. It will be appreciated that the advantages described herein can be obtained while modifying the disclosed cutter to mount to the mineral processing pipeline in a different way.Where the cutter assembly 20 is inserted into a horizontal mineral processing pipeline, and the process flow comprises a solids-containing slurry, the cutter is advantageously oriented substantially vertically. Gravity causes downward settlement of particulate solids in the slurry, and is the only acting force of notable effect. In this orientation, the cutter is generally aligned with the direction of settlement (and oriented radially relative to the cross-section of process flow). The cutter is therefore able to be exposed to, and therefore divert, a representative sample of the process slurry, particularly where the slurry has settled into settlement layers.

[0070] Figure 3(c) shows the cross-section A-A of Figure 3(b). The elongate body 131 includes a leading edge 132 and lateral walls 136a and 136b positioned at an oblique angle to the direction of process flow (best seen in Figure 3 (c)) with the lateral walls 136a and 136b diverging away from each other from the leading edge 132. The diverging lateral walls 136a and 136b and the leading edge 132a together form a flow-facing side of the cutter. The cutter 130 further comprises a trailing edge 132b that is opposed to the leading edge 132a. The cutter 130 further includes respective converging lateral walls 137a and 137b that extend between the diverging lateral walls 136a and 136b and the trailing edge 132b. The converging lateral walls 137a and 137b and trailing edge 132b together form a downstream, or "wake-side", side of the cutter 130. Accordingly, in this embodiment, the elongate body 131 has a generally rhomboid shaped cross section, best seen in Figure 3 (c). However, being on the leeward side of the flow, the geometry of the lateral walls 137a and 137b is mostly supportive. It is therefore not essential that the lateral walls 137a and 137b are symmetric to the flow-facing side of the cutter and could still perform their function with another geometry.

[0071] At least one of the lateral walls 136a and 136b, preferably both, includes a series of longitudinally spaced elongate openings 133 proximal to the leading edge 132, with the openings 133 being configured to receive the sample flow. The longitudinal axes Y-Y of the openings 133 are generally perpendicular to the longitudinal axis X-X of the elongate body 131 and extend generally in the direction of process flow Fl. Each opening 133 is tapered along the longitudinal axis Y-Y such that it becomes gradually wider from the upstream end towards the downstream end thereof. This configuration minimizes the risk of blocking the openings 133 by particles in the process flow (such as in the case of the process flow comprising a slurry) as they traverse across the flow-facing side of the cutter 130 in the process flow direction, by reducing the probability of wedging of such particles. The openings 133 are also spaced downstream from the leading edge 132a of the cutter 130. This configuration enables large particles (such as 1mm or larger) which might otherwise cause blockages or impact and wear damage, to not directly impact the openings in a head-on manner but to be instead deflected or to adopt a rolling momentum that minimizes blockage of the openings 133. As best seen in Figure 3(b), the downstream ends of the openings 133 terminate on the leeward side ofthe cutter, where a low pressure zone is created by the passing slurry. Additionally, the termination of the openings 133 on the leeward side allows for some small percentage of the slurry to enter and leave the cutter 130, providing a flushing effect and assisting to prevent blockage of the openings. A suitable configuration for the elongate openings 133 is "kite-shaped", (or in other words, an orthodiagonal quadrilateral). Such openings therefore include acute and obtuse angles. The openings are preferably oriented such that the acute angle of each opening is positioned proximal the leading edge 132 of the cutter 130, where the process flow first contacts the opening 133. The obtuse angles of the kite-shaped openings are located on the wake-side (leeward side) of the opening's vertex, within the low-pressure zone of the cutter.

[0072] The ratio of the largest width to the smallest width of the openings 133 depends on the 'sharpness' of the openings 133 on the upstream side. The ratio of the largest width to the smallest width of the openings 133 are greater than 1:1, and may range up to 1000:1.

[0073] Turning now to Figure 3(d), there is a magnification of Detail B of Figure 3(c) showing a detailed cross section of the elongate body 131. Detail B shows the layered construction of the converging lateral walls 137a and 137b. (Diverging lateral walls 136a and 136b are formed in the same manner.) Each lateral wall comprises an inner layer 138a comprising a suitable loadbearing material such as stainless steel and an outer layer 138b comprising one or more suitable wear-resistant and / or impact-resistant sub-layer / s such as natural rubber. Other suitable materials for the wear-resistant and / or impact-resistant sub-layer / s include polymer-based coatings such as PTFE, epoxy-based materials, PPS, ETFE polyurethanes. Other types of wear resistant coatings include thermal spray coatings and tungsten carbide coatings.

[0074] In the illustrated embodiment, the inner layer may be from 4 to 6 mm thick and the outer layer may be from 6 to 10 mm thick. The outer layer 138b is continuous around the leading edge 132a of the cutter 130 such that there are no seams or other areas of weakness that are exposed to the oncoming process flow. Moreover, the outer layer 138b includes openings corresponding to the openings 133 in the lateral walls of the cutter such that the process flow may pass unimpeded into the cutter 130.

[0075] Figure 3(f) is an alternative embodiment of the cross-section A-A in which like reference numerals again refer to like parts. The embodiment in Figure 3(f) shows internal baffles 239 or similar structures. The baffles 239 are arranged at an oblique angle to the direction of process flow Fl. The baffles assist in preventing elongated particles from entering the cutter 230 and causing downstream blockages. The oblique orientation of the baffles 239 further optimizes the opening geometry andminimises surfaces perpendicular to oncoming slurry flow and thereby minimizes cutter wear. Figure 3(f) also shows two outer sub-layers: 238b' and 238b". The outer sub-layers 238b' and 238b" may comprise the same or different materials. Advantageously, the two sub-layers comprise wearresistant materials such as rubber.

[0076] EXAMPLES

[0077] A non-limiting Comparative Example of a prior art cutter and an Example of a cutter of the present disclosure are described below.

[0078] Comparative Example 1.

[0079] A prior art cutter according to Figures 1 and 2 was evaluated in a mineral processing facility under operating conditions with hydrocyclone overflow flow rates ranging from approximately 100 to 300 m3 / hr. As shown in Figures 4(1) and (II), the prior art cutter experienced frequent blockages, typically within days of operation. As seen best from Figure 4(11), these blockages 401 predominantly formed in the lower section of the cutter, where the higher-density fraction of the slurry, containing coarser and heavier particles, accumulated near the pipe floor. Once blockages occurred, continued operation was impeded, necessitating frequent manual intervention. Over time, as illustrated in Figure 4(1), the cutter also exhibited severe material loss due to abrasive wear, progressively reducing the structure to a single remaining lateral wall within weeks, ultimately rendering it inoperable. Despite the application of tungsten carbide coatings to the cutter, neither blockage resistance nor wear resilience was sufficient for sustained operation.

[0080] Example 1

[0081] A cutter having a design as illustrated in Figures 3(a) to (f) was tested under comparable conditions to Comparative Example 1. The cutter demonstrated exceptional blockage resistance, with no instances of operational obstruction during its service life. As shown in Figures 4(111) and 4(IV), the eventual failure in the cutter design was driven primarily by wear, specifically at the leading (attack) edge of the cutter or by liner degradation. The observed wear patterns indicated that the cutter design effectively mitigated the accumulation of dense solids that previously led to premature blockages in Comparative Example 1. The improved cutter design withstood operational conditions for several months— an order of magnitude longer than the prior art cutter— before requiring replacement.

[0082] The primary failure modes observed in the new design were associated with the integrity and resilience of the liner material, rather than structural wear or flow obstruction. In one test case,failure resulted from localized liner degradation, while in the other, material loss was concentrated at the leading edge due to sustained erosive forces.

[0083] Whilst a number of specific embodiments have been described, it should be appreciated that the cutter, cutter assembly, sampler and method of diverting a sample flow may be embodied in many other forms.

[0084] In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word "comprise" and variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the apparatus and method as disclosed herein.

Claims

CLAIMS1. A cutter for diverting a sample flow from a process flow, the cutter having an upstream end and a downstream end, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end, the cutter having:an elongate body having a longitudinal axis and adapted to extend longitudinally across the direction of process flow,the elongate body including a leading edge and lateral walls positioned, in use, at an oblique angle to the direction of process flow with the walls diverging away from each other from the leading edge,at least one of the lateral walls including a series of longitudinally spaced openings proximal to the leading edge, the openings being configured to receive the sample flow.

2. The cutter of claim 1, including a wear-resistant surface that is exposed to the process flow.

3. The cutter of claim 2, wherein the wear-resistant surface comprises a lining material, surface treatment or coating on the cutter.

4. The cutter of claim 2, wherein the wear-resistant surface is selected from rubber, polymer- based coatings such as PTFE, epoxy-based materials, PPS, ETFE polyurethanes, thermal spray coatings and tungsten carbide coatings.

5. The cutter of any preceding claim, wherein the leading edge is angular or sharp.

6. The cutter of claim 5, wherein the leading edge is without a lining material, surface treatment or coating.

7. The cutter of any one of claims 1 to 5, wherein the leading edge is rounded or radiused.

8. The cutter of any preceding claim, wherein the cutter further includes respective converging lateral walls that extend between the diverging lateral walls and a trailing edge of the cutter, the converging lateral walls and trailing edge together form a downstream side of the cutter.

9. The cutter of any preceding claim, wherein the lateral walls are constructed from stainless steel.

10. The cutter of any preceding claim, wherein at least part of the lateral walls are lined or coated with one or more outer wear-resistant and / or impact-resistant layers.

11. The cutter of any preceding claim, wherein the longitudinally spaced openings extend across a maximal cross-sectional extent of the process flow such that they are exposed to, and can divert, a representative cross-section of the process flow.

12. The cutter of claim 12, wherein the longitudinally spaced openings have an elongate configuration with the longitudinal axes of the openings extending generally in the direction of process flow.

13. The cutter of claim 13, wherein each opening is tapered along the longitudinal axis such that it becomes gradually wider from the upstream end towards the downstream end thereof.

14. The cutter of claim 14, further including a narrowing of each opening at the downstream end thereof.

15. The cutter of any preceding claim, wherein each longitudinally spaced opening has an orthodiagonal quadrilateral shape.

16. The cutter of claim 16, wherein the longitudinally spaced openings include acute and obtuse angles, with the openings oriented such that an acute angle of each opening is positioned proximal the leading edge side of the cutter, and the obtuse angles of the openings are located on the leeward side.

17. The cutter of any preceding claim, wherein the ratio of the largest width to the smallest width of the openings is greater than 1:1, such as from 1.66:1.

18. The cutter of any preceding claim, wherein the ratio of the largest width to the smallest width of the openings may be a maximum of 10:1.

19. The cutter of any preceding claim, wherein the openings are spaced downstream from the leading edge of the cutter.

20. The cutter of claim 8, wherein the openings are symmetrical about the longitudinal axis of the cutter so that the cutter is reversible.

21. The cutter of any preceding claim, further including internal baffles, with the baffles arranged at an oblique angle to the direction of process flow to assist in preventing or redirecting elongated particles from entering the cutter and causing downstream blockages.

22. A cutter assembly for use in the collection of a sample flow from a process flow, the cutter assembly including:a housing insertable in a mineral processing pipeline and having an upstream end and a downstream end, wherein in use, the process flow travels generally in a direction from the upstream end to the downstream end;a cutter locatable within the housing between the upstream end and the downstream end, the cutter having:an elongate body having a longitudinal axis and adapted to extend longitudinally across the direction of process flow,the elongate body including a leading edge and lateral walls positioned at an oblique angle to the direction of process flow with the walls diverging away from each other from the leading edge,at least one lateral wall including a series of axially spaced openings therethrough, the openings being configured to receive the sample flow.

23. The cutter assembly of claim 23, wherein the cutter may be inserted and removed from the cutter housing via a port in the housing.

24. The cutter assembly of claim 24, wherein the cutter includes one or more mounting flanges by which the cutter may be secured to the housing using fasteners.

25. A sampler for diverting a sample flow from a process flow, the sampler including:a cutter assembly of claim 23,a sample conduit in fluid communication with the cutter and for passing the sample flow therethrough after it leaves the cutter.

26. A method of diverting a sample flow from a process flow in a mineral processing pipeline using the cutter of claim 1, the pipeline having an upstream end and a downstream end and, in use, the process flow travels generally in a direction from the upstream end to the downstream end, the method including:positioning the cutter within the pipeline such that the elongate body of the cutter extends longitudinally across the direction of process flow, the leading edge of the cutter faces upstream and the lateral walls of the cutter are at an oblique angle to the direction of process flow,causing the process flow to travel from the upstream end towards the downstream end of the pipeline, and diverting a representative sample of the process flow into the longitudinally spaced openings proximal the leading edge of the cutter.

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