AU2007214339B2 - A variable flow control device - Google Patents

Abstract

An adjustable flow control device adapted for incorporation into a pipeline for transportation of an abrasive slurry, the device including a conduit adapted to convey the slurry along a flow path between an inlet and an outlet of the device, and a flow control 5 body supported for movement by an actuator generally transversely into the flow path so as to regulate flow of the slurry through the conduit, the flow control body having a flow control surface extending at least partially in a direction generally axial to the conduit and generally parallel to the flow path. There is also provided an adjustable flow control device adapted for 10 incorporation into a pipeline for transportation of a flowable material, the device including: a conduit adapted to convey the material along a flow path between an inlet and an outlet of the device; flow control means to regulate flow of the material through the conduit; 15 a removable cartridge incorporating the conduit; and a cradle incorporating the inlet and the outlet to the device, the cradle being adapted for integration into the pipeline by respective inlet and outlet end connection means; wherein the removable cartridge is mountable in the cradle and replaceable 20 without the need to remove the cradle from the pipeline. Associated methods of adjustably controlling the flow in a pipeline are also provided. Figure 2 to accompany abstract.

Description

AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant/s: Jindex Pty Limited Actual Inventor/s: Stephen Francis Fowler and Mitchell Gordon Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: A VARIABLE FLOW CONTROL DEVICE Details of Associated Provisional Application No. 2006904764 dated 31 Aug 2006 The following statement is a full description of this invention, including the best method of performing it known to me/us: File: 50967AUP00 -la TITLE OF THE INVENTION "A VARIABLE FLOW CONTROL DEVICE" 5 FIELD OF THE INVENTION The present invention relates generally to variable flow control devices such as valves. The invention has been developed for use in highly abrasive environments such as in ore grinding mills, mining operations and mineral processing plants, and 10 will be described primarily in this context. It will be appreciated, however, that the invention is not limited to these particular fields of use. BACKGROUND OF THE INVENTION The following discussion of the prior art is intended to place the invention in an appropriate technical context and to enable the advantages of it to be properly 15 understood. However, any discussion of the prior art in this specification should not be taken as an express or implied admission that such art is widely known, or forms part of common general knowledge in the field. In a variety of commercial and industrial applications, it is necessary to regulate fluid flow in a pipeline, in conditions that are highly abrasive or corrosive. One such 20 application, by way of example, is slurry pipelines of the type often used in connection with mining and mineral processing operations. Because of the highly abrasive nature of the particulate materials and slurries flowing through these pipes, the associated valves used to regulate flow rates are prone to rapid wear, which necessitates frequent maintenance, repair or replacement. In many applications, this requires the associated 25 section of the mining or mineral processing plant to be shut down, which involves significant expense in terms of plant downtime and lost productivity, to say nothing of the capital and labour cost of the maintenance operation itself. In an attempt to ameliorate this problem, it is known to use "pinch valves" in such applications. A pinch valve typically incorporates a flexible sleeve formed from 30 rubber or similar material, serially integrated into the pipeline by means of complementary end flanges. Pinch bars are disposed on diametrically opposite sides -2 of the sleeve, to define a pinch zone therebetween. An actuator is connected with the pinch bars such that in response to controlled movement of the actuator, the pinch bars are drawn together, so as progressively to pinch the flexible sleeve. As the sleeve is pinched, the effective cross-sectional flow area through the pinch zone is reduced, so 5 as progressively to restrict fluid flow through the valve. Because the change in cross-sectional profile of the flow area through the pinch zone is relatively smooth and progressive, pinch valves are relatively less prone to wear than other conventional valve designs. However, in highly abrasive environments, they remain prone to rapid wear and in some applications typically 10 require substantial maintenance or repair every few weeks. It is an object of the present invention to overcome or substantially ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative. SUMMARY OF THE INVENTION 15 Accordingly, in a first aspect, the invention provides an adjustable flow control device adapted for incorporation into a pipeline for transportation of an abrasive slurry, the device including a conduit adapted to convey the slurry along a flow path between an inlet and an outlet of the device, and a flow control body supported for movement by an actuator generally transversely into the flow path so as to regulate flow of the 20 slurry through the conduit, the flow control body being adapted to extend directly into the flow path of an abrasive slurry and having a flow control surface extending at least partially in a direction generally axial to the conduit and generally parallel to the flow path. Preferably, the flow control surface of the flow control body extends in the axial 25 direction by a distance corresponding to at least 20% of the mean effective internal diameter of the conduit. At increasing levels of preferability, this ratio is at least 50%, 75%, 100%, 150% and 200% respectively. Preferably, the area of the flow control surface is at least 20% of the mean effective cross-sectional flow area of the flow path through the conduit. At increasing -3 levels of preferability, this ratio is at least 50%, 75%, 100%, 150% and 200% respectively. In one preferred embodiment, the flow control body is substantially square or rectangular in transverse cross-sectional profile. In other embodiments, however, the 5 transverse cross-sectional profile of the flow control body may be circular, elliptical or hexagonal, for example, or may be formed with any other suitable geometrical profile, whether symmetrical or otherwise. In one preferred embodiment, the cross-sectional area of the flow control body progressively increases downstream, so that the flow control surface tapers towards the 10 opposing portion of the conduit. The flow control surface is preferably concave, with an arcuate cross-section transverse to the flow path. In one preferred embodiment, the flow control body is formed from an at least partially resilient or elastomeric material such as rubber or polyurethane. It should be appreciated, however, that any other suitable material or materials may alternatively be 15 used, including metals, ceramics, plastics, glasses, cements or composite materials. Preferably, the conduit forms part of a discrete pipe section incorporating the inlet and the outlet to the device, the pipe section being adapted for integration into a pipeline by means of respective inlet and outlet end flanges. In the preferred embodiment, the pipe section is formed from a wear resistant material such as high 20 carbon steel, cast iron or white iron. In another embodiment, the pipe section is formed substantially from a softer material but incorporates a wear-resistant lining, which may optionally be replaceable. Preferably, the pipe section includes a removable cartridge incorporating the conduit, and a cradle incorporating the inlet and the outlet to the device, the cradle 25 being adapted for integration into a pipeline by means of respective inlet and outlet end flanges. The removable cartridge is preferably mountable in the cradle and replaceable without the need to remove the cradle from the pipeline. Preferably, the inlet and outlet flanges encompass respective ends of the removable cartridge to secure the removable cartridge in the cradle. The cradle -4 preferably includes a base portion and a detachable flange portion on at least one of the inlet and outlet flanges. The detachable flange portion is preferably detachable to permit removal of the removable cartridge without the need to remove the base portion from the pipeline. 5 In another preferred embodiment, the cradle also includes at least one hinged locking portion movable between an open position to permit removal of the removable cartridge, and a locked position to secure the removable cartridge in the cradle. Preferably, the cradle further includes a detachable head portion to facilitate securing of the removable cartridge. The hinged locking portion in the locked position also 10 preferably secures the detachable head portion to the base portion. Preferably, the cradle includes a tongue adapted for keyed engagement with a complementary groove in an outer circumferential surface of the removable cartridge to align the removable cartridge to a predetermined position relative to the cradle. Preferably, the flow path defined by the conduit in a flow control zone 15 immediately adjacent the flow control body is generally U-shaped in cross-sectional profile, and transitions toward a generally circular cross-sectional profile in the vicinity of the inlet and the outlet. The transition from the circular cross-sectional profile of the flow path at the inlet, to the U-shaped profile in the control zone, upstream of the flow control body, is preferably smooth and progressive. The transition from the U 20 shaped cross-sectional profile of the flow path in the control zone, to the circular cross sectional profile at the outlet, downstream of the control zone, is optionally also smooth and progressive, although the precise nature of this downstream transition is less significant, particularly in low-pressure applications. It should be appreciated, however, that the profile of the flow path need not be U-shaped in the flow control 25 zone or circular at the inlet and outlet. A variety of other profiles, both uniform and non-uniform, including square, oval and circular for example, are also envisaged. In one preferred embodiment, the flow control body is adapted to extend only partially into the flow path, so as only partially to restrict fluid flow through the conduit. In other preferred embodiments, however, the flow control body is adapted to -5 extend fully into the flow path, thereby permitting fluid flow through the conduit to be completely restricted. Preferably, the actuator includes an hydraulic or pneumatic cylinder, supported adjacent the conduit by means of a frame, and operatively connected to the flow 5 control body by means of a push-rod. It will be appreciated, however, that a variety of alternative actuation mechanisms may be used, either individually or in combination, such as mechanical linkages, gear drives, cable drives, cams, screw drives, electro magnetic solenoids, or the like. In particular, it should be appreciated that not all actuation mechanisms will be linear, and not all such mechanisms will require the use 10 of a push-rod. In one preferred form of the invention, the flow control body is adapted to be removed and replaced, when worn to a predetermined extent. In another preferred form of the invention, the device is configured to allow successive flow control bodies to be added in modular form to preceding flow control bodies, as the preceding bodies 15 progressively wear, so as to avoid the need for process downtime while worn flow control bodies are replaced. In one embodiment, the successive flow control bodies are added or stacked axially along the flow path. In another embodiment, the successive flow control bodies are added or stacked transversely to the flow path. Preferably, the actuation mechanism and the associated supporting frame are 20 arranged to permit replacement of the flow control body without the need to remove the conduit from the pipeline. In a second aspect, the invention provides an adjustable flow control device adapted for incorporation into a pipeline for transportation of a flowable material, the device including: 25 a conduit adapted to convey the material along a flow path between an inlet and an outlet of the device; flow control means to regulate flow of the material through the conduit; a removable cartridge incorporating the conduit; and -6 a cradle incorporating the inlet and the outlet to the device, the cradle being adapted for integration into the pipeline by respective inlet and outlet end connection means; wherein the removable cartridge is mountable in the cradle and replaceable 5 without the need to remove the cradle from the pipeline. Preferably, the connection means take the form of respective inlet and outlet flanges adapted for connection with complementary flanges formed in corresponding sections of the pipeline. Preferably, the inlet and outlet flanges encompass respective ends of the 10 removable cartridge to secure the removable cartridge in the cradle. The cradle preferably includes a base portion and a detachable flange portion on at least one of the inlet and outlet flanges. The detachable flange portion is preferably detachable to permit removal of the removable cartridge without the need to remove the base portion from the pipeline. 15 In another preferred embodiment, the cradle also includes at least one hinged locking portion movable between an open position to permit removal of the removable cartridge, and a locked position to secure the removable cartridge in the cradle. Preferably, the cradle further includes a detachable head portion to facilitate securing of the removable cartridge. The hinged locking portion in the locked position also 20 preferably secures the detachable head portion to the base portion. Preferably, the cradle includes a tongue adapted for keyed engagement with a complementary groove in an outer circumferential surface of the removable cartridge to align the removable cartridge to a predetermined position relative to the cradle. In a third aspect, the invention provides a method of adjustably controlling the 25 flow of an abrasive slurry in a pipeline, the method including the steps of: providing an adjustable flow control device according to the first aspect of the invention described above; conveying the slurry along the flow path between the inlet and the outlet of the device; and -7 moving the flow control body generally transversely into the flow path so as to regulate flow of the slurry through the conduit. In a fourth aspect, the invention provides a method of adjustably controlling the flow of a flowable material in a pipeline, the method including the steps of 5 providing an adjustable flow control device according to the second aspect of the invention described above; and integrating the cradle into the pipeline by connecting the inlet and the outlet to the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS 10 Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cross-sectional side elevation view of a flow control device, with the flow control body fully retracted, according to a first embodiment of the invention; Figure 2 is a cross-sectional side elevation showing the flow control device of 15 figure 1, with the flow control body extended in an operative position, and partially worn; Figure 3 is a cross-sectional end elevation of the flow control device of figure 2; Figure 4 is an enlarged cross-sectional view of region 4-4 of figure 3; Figure 5 is a side elevation view of the main conduit of the flow control device 20 shown in figures I to 4; Figure 6 is an end elevation view of the main conduit shown in figure 5; Figure 7 is a cross-sectional side elevation showing the flow control device of figures 1 to 4, mounted to a flotation tank, and depicting a mechanism for actuator retraction to facilitate maintenance in situ; 25 Figure 8A is a horizontal or transverse cross-section of the flow control body of the flow control device illustrated in figures 1 to 4; -8 Figures 8B to 8E show the cross-sectional profiles of respective flow control bodies, according to a corresponding series of alternative embodiments of the invention; Figures 9A to 9F show a series of perspective views of alternative forms of the 5 flow control body for use in flow control devices, according to a corresponding series of further embodiments of the invention; Figure 10 is an isometric view of a flow control device according to a second embodiment of the invention; and Figure 1 1 is an exploded isometric view of the flow control device of figure 10, 10 with the hinged locking portions in their open positions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring initially to figures I to 3, the invention provides an adjustable flow control device 1, adapted for incorporation into a pipeline (not shown) for transportation of abrasive slurries, mineral ore suspensions, or similar materials. In 15 one preferred application, the device is adapted to be incorporated into the pipeline between a grinding mill and a flotation cell of a grinding circuit in a mineral separation plant, although it will be appreciated that the invention is not limited to this particular application. The device includes a conduit 3 adapted to convey the slurry along an axial flow 20 path 4, between an inlet 5 and an outlet 6. The conduit is connected to adjoining pipe sections by respective inlet and outlet end flanges 7 and 8. A flow control body 10 is supported for movement by an actuator 11, in a generally vertical direction (when viewing the drawings) transverse to the flow path, so as to regulate flow of the slurry through the conduit. The flow control body includes a flow control surface 15, 25 extending in a direction generally axial to the conduit 3, substantially parallel to the flow path 4. In the embodiment of the invention illustrated in figures I to 3, the flow control body is generally square in cross-sectional profile, as shown in figure 8A, and the flow -9 control surface 15, being essentially the lowermost end face of that body exposed to the flow path, is correspondingly shaped. The flow control surface extends in the axial direction by a distance A (see figure 1) corresponding to at least 20% of the nominal or mean effective diameter B of the flow path through the conduit. In other 5 embodiments, this ratio is at least 50%, 75%, 100%, 150% and 200% respectively. The effective area of the flow control surface is preferably at least 20% of the mean cross-sectional area of the flow path through the conduit. In other embodiments, this ratio is at least 50%, 75%, 100%, 1 50% and 200% respectively. In the embodiment of the invention illustrated in figures 1 to 3, the flow control 10 surface is substantially flat, and extends in a plane substantially parallel to the axis of the conduit and the direction of the flow path. One advantage of this and similar configurations is that as the flow control surface progressively wears from the upstream edge toward the downstream edge, a wear ledge 16 forms, as best seen in figure 2, and this acts in certain circumstances to deflect part of the flow downwardly 15 toward the bottom surface of the conduit. As this wear ledge recedes toward the downstream edge of the flow control surface, the point at which the deflected flow impinges upon the bottom surface of the conduit correspondingly recedes. This progressive effect is believed to reduce wear on the inner surface of the conduit, by distributing the impact over a larger surface area. 20 In other embodiments of the invention, the flow control surface may be flat, but inclined relative to the axis of the conduit. In still other embodiments, the flow control surface may be multi-faceted, or curved, as required to provide optimum flow and wear characteristics in particular applications. A series of such embodiments is illustrated in figures 9A to 9F. These flow and wear characteristics will vary 25 depending upon one or more of the nature of the material to be transported through the pipeline, the effective diameter of the conduit, the effective length of the flow path through the flow control device, the intended range of flow rates, the length of the duty cycle between scheduled maintenance operations, the material composition of the flow control body and the conduit, and other relevant factors. In the embodiments such as 30 those illustrated in figures 9D, 9E and 9F, where the flow control surface is curved or inclined respect to the direction of the flow path, the ratios previously defined with -10 respect to the extent and area of the flow control surface, are calculated on the basis of the total area of the flow control surface that is non-normal to the flow path. In the embodiment as illustrated in figures I to 3, the flow control body is formed from a solid block of polyurethane which has been found, somewhat 5 unexpectedly, to exhibit particularly advantageous wear characteristics in the context of the present invention, notwithstanding the relative softness of this material. It should be appreciated, however, that other materials, or combinations of materials, can alternatively be used. For example, the flow control body could be formed from other elastomeric or partially elastomeric materials such as rubber or similar synthetics. 10 Further alternatives include metals, ceramics, plastics, glasses and cements, as well as composites such as fibreglass, carbon fibre and fibre cement. Layered or laminated structures formed from combinations of such materials are also envisaged. Most preferably, however, the flow control body is formed as a substantially rigid and substantially solid structure, of a composition suitable to extend directly into the flow 15 path of an abrasive slurry. The conduit 3 is formed from a suitable wear-resistant material such as high carbon steel, cast iron or white iron. Alternatively, the conduit may be formed at least partially from a relatively softer material, but may incorporate a wear-resistant lining or insert to minimise abrasive wear, particularly in the vicinity of the flow control 20 body. Such linings or inserts may optionally be replaceable, so as to optimise the service life of the device, subject to appropriate periodic maintenance. The flow path 4 defined by the conduit includes a flow control zone 20 in the immediate vicinity of the flow control body. In the embodiment of the invention as illustrated, this flow control zone is substantially U-shaped in cross-sectional profile, 25 and transitions toward a generally circular cross-sectional profile in the vicinity of both the inlet and the outlet, as best seen in figures 3, 5 and 6. The transition zone 21 from the U-shaped cross-sectional profile of the flow path in the control zone, to the substantially circular cross-sectional profile at the inlet, upstream of the flow control body, is smooth and progressive. The transition from the U-shaped profile in the 30 control zone, to the substantially circular profile at the outlet, downstream of the flow control body, is less critical in many applications and in the embodiment as illustrated, this downstream transition is relatively sharp. It should be appreciated, however, that in other embodiments, the downstream transition may also be relatively smooth and progressive, so as to minimise turbulence, energy loss and wear in this downstream zone. 5 As best seen in figure 4, the device includes a sealing mechanism 21, adapted to prevent significant leakage of fluid from within the conduit around the flow control body, while accommodating the necessary sliding movement of the flow control body relative to the conduit. More specifically, the sealing mechanism includes a compression plate 22, which is mounted to an upper surface of the conduit, around an 10 aperture corresponding in shape to the flow control body, by bolts 23. A compression shoulder 24 is formed in the inner peripheral edge of the conduit, around the aperture, to accommodate packing elements 25 and a compression ring 26. The packing elements and compression ring are thereby sandwiched between the upper surface of the compression shoulder and the lower surface of the compression ring, whereby upon 15 tightening the bolts 23, these packing elements are squeezed into peripheral sealing engagement with the side wall of the flow control body. Flushing ports are provided, as required, and a peripheral groove 27 is adapted to retain water, for improved lubrication. Although a specific sealing mechanism has been described by way of example, it should be appreciated that a variety of alternative sealing mechanisms may 20 be used and indeed, that some embodiments or applications of the invention may not require a sealing mechanism for the flow control body. The actuator 1 1 takes the form of an hydraulic or pneumatic cylinder 30 supported adjacent to the conduit by means of a support frame 31. The cylinder is operatively connected to the flow control body by means of a push-rod 32. It will be 25 appreciated, however, that a variety of alternative actuation mechanisms may be used, either individually or in combination, including electric motors, servo motors mechanical drives, gear drives, electro-magnetic solenoids, and the like. Most preferably, the actuator and the associated support frame are disposed to permit removal and replacement of the flow control body in situ, without requiring the 30 conduit to be removed from the pipeline. This functionality is illustrated in figure 7, which shows the flow control device mounted to the outlet of a flotation tank 33.

-12 In one form of the invention, the flow control body is adapted to be removed and replaced, when worn to a predetermined extent and in this regard, a series of conductive wire loops are preferably embedded within the flow control body itself, as part of an automatic wear-detection circuit. In another form of the invention, however, 5 the device is arranged to allow successive flow control bodies to be added in modular form to preceding flow control bodies, as the preceding bodies progressively wear. In this way, the flov control body becomes effectively continuous, thereby avoiding the need for process downtime while worn flow control bodies are replaced. In other embodiments, the flow control body may simply be formed with sufficient length to 10 allow substantial wear in the direction of the longitudinal axis of the flow control body, between required maintenance intervals. This contrasts with pinch valves and the like, in which the effective wear depth is inherently minimal, being effectively limited to the thickness of the flexible rubber sleeve. In the embodiment of the invention as illustrated, the flow control body is 15 adapted to extend only partially into the flow path, so as only partially to restrict fluid flow through the control zone. In this regard, the fully extended position is essentially being illustrated in figures 2 and 3. This form of the invention is suitable in applications where it is not necessary to completely shut off flow through the conduit, and/or in applications where supplementary shut-off valves are provided for this 20 purpose. In alternative embodiments, however, the flow control body may be designed to close off the flow path in the control zone. This may be achieved by providing the lowermost portion of the flow control surface on the flow control body with a profile corresponding to the lower inside surface of the conduit in the control zone. Alternatively, the inner surface of the conduit may be formed with cutouts or recesses 25 in the control zone, to accommodate the flow control body in an extended position whereby the flow path is effectively shut off. Figures 9A to 9F show a series of alternative forms of the flow control body, which may be used in connection with the flow control device to tailor performance and wear characteristics according to particular applications and design criteria. In 30 each case, the flow path through the conduit is indicated by vector X, and the direction of movement of the flow control body in response to operation of the actuator, is -13 indicated by vector Y. It will be appreciated that in some of these embodiments, such as those shown in figures 9D to 9F, the flow control surface is curved in the axial direction (ie the direction of the flow path) while in other embodiments such as those shown in figures 9A to 9C, this surface is curved in the transverse direction. 5 In the embodiment of figure 9F, the flow control body is provided with a number of flow control surfaces, only one of which is substantially operative at any given time. In this case, the flow control body is provided with an indexing mechanism (not shown) whereby, as each flow control surface is worn to a predetermined degree, the flow control body may be indexed so as to introduce the 10 next flow control surface into the flow control zone, without requiring any significant process downtime. By this means, the flow control body only needs to be replaced when all of the associated flow control surfaces have been deployed, whereby the maintenance cycle can be significantly extended. Figures 10 and I1 illustrate a further preferred embodiment of the invention, 15 wherein features common to this embodiment and those described above have the same reference numerals. In the embodiment illustrated in figures 10 and 11, a removable cartridge 34 incorporates the conduit 3, and a cradle 35 incorporates the inlet 5 and the outlet 6 to the device. The cradle is adapted for integration into a pipeline (not shown) by means of respective inlet and outlet end flanges 7 and 8. The 20 removable cartridge 34 is mountable in the cradle 35 and replaceable without the need to remove the cradle from the pipeline. The inlet and outlet flanges 7 and 8 encompass respective ends of the removable cartridge 34 to secure the removable cartridge in the cradle 35. The cradle 35 includes a base portion 36 and a detachable flange portion 37 on the inlet flange 7. 25 The detachable flange portion 37 is detachable to permit removal of the cartridge 34 without the need to remove the base portion 36 from the pipeline. The detachable flange portion 37 is secured by bolts to the pipeline. Preferably, the sides of the detachable flange portion 37, that are in contact with the remainder of the inlet flange 7 when attached, are tapered towards the longitudinal axis of the cradle 35. The tapered 30 sides result in a friction fit between the detachable flange portion 37 and the remainder of the flange 7.

-14 The cradle 35 also includes four hinged locking portions, each in the form of arcuate flaps 38, which conform to an outer circumferential surface 39 of the removable cartridge 34. The flaps 38 are movable between an open position to permit removal of the removable cartridge 34, as best seen in figure 11, and a locked position 5 to secure the removable cartridge in the cradle, as best seen in figure 10. The cradle 35 further includes a detachable head portion 40 to facilitate securing of the removable cartridge 34. The removable cartridge 34 includes circumferentially extending recesses 41 on the outer circumferential surface 39. The detachable head portion 40 includes flanges 42, each having a shape that is 10 complementary with a respective recess 41. When the detachable head portion 40 is attached to the base portion 36, each flange 42 fits within the respective recess 41, substantially flush with the outer circumferential surface 39. Since the hinged locking flaps 38, in their locking positions, wrap conformingly around the outer circumferential surface 39, they also wrap around the flanges 42, thereby securing the 15 detachable head portion 40 to the base portion 36. The cradle 35 also includes a longitudinally extending tongue 43 adapted for keyed engagement with a complementary groove 44 in the outer circumferential surface 41 of the removable cartridge 34. The keyed engagement between the tongue 43 and groove 44 aligns the removable cartridge 34 to a predetermined position 20 relative to the cradle 35. The invention in a further aspect also provides a method of adjustably controlling the flow of an abrasive slurry in a pipeline. One preferred embodiment includes the steps of providing the adjustable flow control device 1, conveying the slurry along the flow path 4 between the inlet 5 and the outlet 6 of the device, and 25 moving the flow control body 10 generally transversely into the flow path 4 so as to regulate flow of the slurry through the conduit 3. The invention in yet another aspect provides a method of adjustably controlling the flow of a flowable material in a pipeline. One preferred embodiment includes the steps of providing the adjustable flow control device 1, and integrating the cradle 35 -15 into the pipeline (not shown) by connecting the inlet 5 and the outlet 6 to the pipeline by means of respective inlet and outlet end flanges 7 and 8. The invention in its preferred embodiments provides a relatively simple, efficient, reliable, robust and cost-effective flow control device which is ideally suited 5 for use in highly abrasive environments such as those associated with ore grinding mills, flotation cells and thickeners, and which has relatively low maintenance requirements. In these respects, the invention represents a practical and commercially significant improvement over the prior art. Although the invention has been described with reference to specific examples, 10 it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (30)

1. An adjustable flow control device adapted for incorporation into a pipeline for transportation of an abrasive slurry, the device including: a conduit adapted to convey the slurry along a flow path between an inlet and 5 an outlet of the device, and a flow control body supported for movement by an actuator generally transversely into the flow path so as to regulate flow of the slurry through the conduit, the flow control body being adapted to extend directly into the flow path of an abrasive slurry and having a flow control surface extending at least partially in a 10 direction generally axial to the conduit and generally parallel to the flow path.

2. An adjustable flow control device according to claim 1 wherein the flow control surface of the flow control body extends in the axial direction by a distance corresponding to at least 20% of the mean effective internal diameter of the conduit.

3. An adjustable flow control device according to claim 1 or claim 2 wherein the 15 area of the flow control surface is at least 20% of the mean effective cross-sectional flow area of the flow path through the conduit.

4. An adjustable flow control device according to any one of claims 1 to 3 wherein the flow control body is substantially rectangular, square, circular, elliptical or hexagonal in transverse cross-sectional profile. 20

5. An adjustable flow control device according to any one of claims 1 to 4 wherein the cross-sectional area of the flow control body progressively increases downstream, such that the flow control surface tapers towards the opposing portion of the conduit.

6. An adjustable flow control device according to any one of claims 1 to 5 wherein 25 the flow control surface is concave, with an arcuate cross-section transverse to the flow path.

7. An adjustable flow control device according to any one of claims 1 to 6 wherein the flow control body is formed from an at least partially resilient material. -17

8. An adjustable flow control device according to any one of claims 1 to 7 wherein the flow control body is formed from an at least partially elastomeric material.

9. An adjustable flow control device according to claim 8 wherein the elastomeric material is one of rubber and polyurethane. 5

10. An adjustable flow control device according to any one of claims 1 to 6 wherein the flow control body is formed at least partially from any one of metal, ceramic, plastic, glass, cement and composite material.

11. An adjustable flow control device according to any one of claims 1 to 10 wherein the conduit forms part of a discrete pipe section incorporating the inlet and 10 the outlet to the device, the pipe section being adapted for integration into a pipeline by means of respective inlet and outlet end flanges.

12. An adjustable flow control device according to claim 11, including a removable cartridge incorporating the conduit, and a cradle incorporating the inlet and the outlet to the device, the cradle being adapted for integration into a pipeline by 15 means of respective inlet and outlet end flanges.

13. An adjustable flow control device according to claim 12 wherein the removable cartridge is mountable in the cradle and replaceable without the need to remove the cradle from the pipeline.

14. An adjustable flow control device according to claim 12 or claim 13 wherein 20 the inlet and outlet end flanges encompass respective ends of the removable cartridge to secure the removable cartridge in the cradle.

15. An adjustable flow control device according to any one of claims 12 to 14 wherein the cradle includes a base portion and a detachable flange portion on at least one of the inlet and outlet flanges. 25

16. An adjustable flow control device according to claim 15 wherein the detachable flange portion is detachable to permit removal of the removable cartridge without the need to remove the base portion from the pipeline. -18

17. An adjustable flow control device according to claim 15 or claim 16 wherein the cradle includes a detachable head portion to facilitate securing of the removable cartridge.

18. An adjustable flow control device according to any one of claims 12 to 17 5 wherein the cradle includes at least one hinged locking portion movable between an open position to permit removal of the removable cartridge, and a locked position to secure the removable cartridge in the cradle.

19. An adjustable flow control device according to claim 18, when dependent on claim 17, wherein the hinged locking portion in the locked position secures the 10 detachable head portion to the base portion.

20. An adjustable flow control device according to any one of claims 12 to 19 wherein the cradle includes a tongue adapted for keyed engagement with a complementary groove in an outer circumferential surface of the removable cartridge to align the removable cartridge to a predetermined position relative to the 15 cradle.

21. An adjustable flow control device according to any one of claims 1 to 20 wherein the flow path defined by the conduit in a flow control zone immediately adjacent the flow control body is generally U-shaped in cross-sectional profile, and transitions toward a generally circular cross-sectional profile in the vicinity of the 20 inlet and the outlet.

22. An adjustable flow control device according to any one of claims 1 to 21 wherein the flow control body is adapted to extend partially into the flow path, such that the fluid flow through the conduit is partially restricted.

23. An adjustable flow control device according to any one of claims 1 to 21 25 wherein the flow control body is adapted to extend fully into the flow path, such that the fluid flow through the conduit is completely restricted.

24. An adjustable flow control device according to any one of claims 1 to 23 wherein the actuator includes a hydraulic or pneumatic cylinder, supported adjacent -19 the conduit by means of a frame, and operatively connected to the flow control body by means of a push-rod.

25. An adjustable flow control device according to any one of claims 1 to 24 wherein the flow control body is adapted to be removed and replaced, when worn to 5 a predetermined extent.

26. An adjustable flow control device according to any one of claims 1 to 25 configured to allow successive flow control bodies to be added in modular form to preceding flow control bodies, as the preceding bodies progressively wear, such that process downtime is minimised while worn flow control bodies are replaced. 10

27. An adjustable flow control device according to claim 24 wherein the actuator and the associated supporting frame are arranged to permit replacement of the flow control body without the need to remove the conduit from the pipeline.

28. A method of adjustably controlling the flow of an abrasive slurry in a pipeline, the method including the steps of: 15 providing an adjustable flow control device according to any one of claims 1 to 27; conveying the slurry along the flow path between the inlet and the outlet of the device; and moving the flow control body generally transversely into the flow path so as to 20 regulate flow of the slurry through the conduit.

29. An adjustable flow control device adapted for incorporation into a pipeline for transportation of an abrasive slurry, the device being substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. 25

30. A method of adjustably controlling the flow of an abrasive slurry in a pipeline, the method being substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.