WO2013059867A1

WO2013059867A1 - Conveyor belt sampler

Info

Publication number: WO2013059867A1
Application number: PCT/AU2012/001299
Authority: WO
Inventors: Noel William Alexander Lambert
Original assignee: Newcastle Innovation Limited
Priority date: 2011-10-25
Filing date: 2012-10-25
Publication date: 2013-05-02
Also published as: AU2012327863A1

Abstract

A conveyor belt sampler operates by diverting the belt (1) sharply downwardly over an upper roller (2) positioned beneath the belt (1) to a lower roller (5) engaging the upper surface (6) of the belt and directing it back to the general run of belt (7) in the conveyor. Material falling from, or projected by, the belt passing over the upper roller (2) is sampled in the cutter bucket (8) of a falling stream sample cutter, moving transversely through the falling material as shown at (16). Various options include the insertion of a sampling conveyor between the upper roller (2) and the cutter bucket (8) to allow a slower sampling speed and the incorporation of a weightometer (19) in the sampling conveyor.

Description

"CONVEYOR BELT SAMPLER" Background of the Invention

[0001 ] This invention relates to a conveyor belt sampler and has been devised particularly though not solely for sampling minerals being conveyed on a belt conveyor from a mine into a processing plant.

[0002] Billions of tonnes of materials are transferred by conveyor every year and most of this needs to be sampled for quality control, plant regulation, or for checking that sales obligations are met. In many instances, the mass of this material must also be accurately measured.

[0003] Falling-stream samplers are the most accurate way to sample the material on a conveyor belt but these samplers are difficult to retrofit to existing conveyor belt situations and often have access and availability problems.

[0004] Cross-belt samplers are a much cheaper alternative to retrofit, and are often installed in new plant, but are not as accurate as falling-stream samplers.

[0005] Weightometers are often placed under belt conveyors to measure the mass of materials being conveyed, but they often have accuracy problems due to the length, speed and tension in the conveyor belt.

[0006] It is a further problem of falling-stream samplers that they require significant vertical space between the conveyor discharge point and any other structure to allow the falling-stream cutter to be placed and to move. Due to this height requirement, it is very difficult and expensive to retrofit falling-stream samplers into existing plants. They are often placed at a great height above loading bins or plant feed entry points causing problems with access and potential safety problems. It also means that often falling- stream samplers in these locations are not given the maintenance work that they should due to safety and access problems.

[0007] Falling-stream samplers also require that the conveyor be stopped whilst maintenance work is carried out and this interferes with production. Summary of the Invention

[0008] The present invention therefore provides apparatus for sampling material being conveyed on a primary belt conveyor having a general run of belt, the apparatus including an upper roller positioned beneath the belt of the conveyor and arranged to divert the belt steeply downwardly from the general run of belt, a lower roller positioned generally below the upper roller, arranged to engage the upper surface of the belt and redirect the belt to the general run of belt, and a sampler arranged to select and sample material falling from the belt as it is diverted downwardly by the upper roller.

[0009] Preferably the sampler comprises a falling-stream sample cutter having a cutter bucket arranged to traverse material falling from the belt adjacent the upper roller.

[0010] Preferably the apparatus includes a separate sampling conveyor positioned to receive material falling from the belt as it is diverted downwardly by the upper roller and convey that material above the general run of belt before discharging it in a stream on to the general run of belt below, the sampler comprising a falling-stream sample cutter having a cutter bucket arranged to traverse the stream discharging from the sampling conveyor.

[001 1 ] Preferably the sampling conveyor is wider than the primary conveyor and arranged to run at a slower speed than the primary conveyor, and wherein a weightometer is positioned beneath the belt of the sampling conveyor.

[0012] Preferably the apparatus further includes an impact conveyor positioned between the upper roller and the sampling conveyor and arranged to receive material falling from the belt as it is diverted downwardly by the upper roller and discharge that material on to the impact conveyor, the impact conveyor having substantially the same width as the sampling conveyor and running at substantially the same speed as the sampling conveyor. Brief Description of the Drawings

[0013] Notwithstanding any other forms that may fall within its scope, one preferred form of the invention and variations thereof will now be described with reference to the accompanying drawings in which:

[0014] Figure 1 is a diagrammatic perspective view of a conveyor belt sampler according to the invention;

[0015] Figure 2 is a diagrammatic elevation of the apparatus shown in Figure 1 ;

[0016] Figure 3 is a plan view of the apparatus shown in Figure 1 ;

[0017] Figure 4 is a diagrammatic perspective view of a conveyor belt sampler according to the invention incorporating a sampling conveyor;

[0018] Figure 5 is a diagrammatic elevation of the apparatus shown in Figure 4;

[0019] Figure 6 is a plan view of the apparatus shown in Figure 4;

[0020] Figure 7 is a diagrammatic perspective view of a conveyor belt sampler according to the invention incorporating both a sampling conveyor and an impact conveyor;

[0021 ] Figure 8 is a diagrammatic elevation of the apparatus shown in Figure 7;

[0022] Figure 9 is a plan view of the apparatus shown in Figure 7;

[0023] Figure 10 is a diagrammatic perspective view of a conveyor belt sampler according to the invention wherein material to be sampled is projected upwardly into the sampler;

[0024] Figure 1 1 is a diagrammatic elevation of the apparatus shown in Figure 10; [0025] Figure 12 is a similar view to Figure 10 incorporating a sampling conveyor; and

[0026] Figure 13 is a diagrammatic elevation of the apparatus shown in Figure 12. Preferred Embodiments of the Invention

[0027] The form of the invention now described and shown diagrammatically in the accompanying drawings is particularly intended for the sampling of mined materials such as coal, as it is transported on a primary conveyor belt 1 , along a general run of belt 7, to a destination which may, for example, be a processing plant.

[0028] The primary conveyor 1 is provided with an upper roller 2 positioned beneath the belt 3 of the conveyor and arranged to divert the belt steepwardly downwardly over belt portion 4 from the general run of belt 7.

[0029] A lower roller 5 is positioned generally below the upper roller and arranged to engage the upper surface of the belt at 6 and redirect the belt to the general run of belt 7.

[0030] A falling-stream sample cutter having a cutter bucket 8 is located and arranged to select and sample material falling from the belt as it is diverted downwardly by the upper roller 2. The falling-stream sample cutter typically includes a bucket of the type shown diagrammatically at 8, movable along transverse rails beneath the discharge stream 17 from the primary conveyor at 3 as shown by arrows 16 in the manner which is well known in the art.

[0031 ] Material that is not collected in the bucket 8 of the falling-stream sample cutter lands back on the general run of belt 7 as shown at 18 where it continues to be transported toward the destination.

[0032] In order to make provision for the weighing of material as it passes along the primary conveyor, the apparatus can optionally include a sampling conveyor 9 as shown in Figures 4, 5 and 6. The sampling conveyor comprises a short conveyor belt 10 entrained over end rollers 1 1 and 12 and positioned to receive material falling from the primary belt at 3 as it is diverted downwardly by the upper roller 2.

[0033] The sampling conveyor then conveys that material above the general run of belt 7 before discharging it in a stream at 13 on to the general run of belt 7 below.

[0034] As before, a falling-stream cutter bucket 8 is provided to sample the material falling from the discharge 13 of the sampling conveyor 9 on to the general run of belt 7 below.

[0035] In order to weigh the material, the sampling conveyor 10 may be provided with a weightometer 19 as is generally well known to those skilled in the art positioned beneath the upper run 10 of the sampling conveyor 9. In order to make the operation of the weightometer more accurate, the sampling conveyor 9 may be provided having a greater width than the width of the primary conveyor belt 1 . This can be clearly seen in Figure 6 where the primary conveyor belt shown at 1 and 7 is considerably narrower than the belt 10 on the sampling conveyor 9.

[0036] By making the sampling conveyor 9 significantly wider than the primary conveyor belt 1 as can be clearly seen in Figure 6, the speed of the sampling conveyor can be significantly reduced while still maintaining the same throughput of material from the primary conveyor 1 . For example, if the primary conveyor is operating at 6 metres per second and the sampling conveyor is three times wider than the primary conveyor 1 , then the sampling conveyor 4 need only operate at 2 metres per second in order to maintain the flow of material from the primary conveyor 1 . This feature allows for significantly more accurate operation of the falling-stream sampler 8 and the weightometer 19.

[0037] In order to further improve the efficiency of the weightometer and to allow for gentle movement of the material onto the sampling conveyor 9, an impact conveyor 14 may also be provided positioned between the upper roller 2 and the sampling conveyor 9 as shown in Figures 7, 8 and 9. The impact conveyor 14 is arranged to receive material falling from the primary belt conveyor 1 as it is diverted downwardly by the upper roller 2 as shown by arrow 20 and to discharge that material at 21 on to the sampling conveyor 9. It is preferred that the impact conveyor 14 has substantially the same width as the sampling conveyor 9 and runs at substantially the same speed as the sampling conveyor.

[0038] The provision of the impact conveyor 14 allows the sampling conveyor 9 to operate at a constant speed without being significantly affected by the inertia of material from the primary conveyor 1 as it falls over the discharge point 3. Because the impact conveyor is preferably the same width as the sampling conveyor 9, the slowing and spreading of the material falling from the primary conveyor belt 1 takes place on the impact conveyor 14 so that the material falling from the discharge end 15 of the impact conveyor on to the sampling conveyor 9 falls at a consistent and gentle rate.

[0039] In this manner the conveyor sampling system according to the invention is more accurate in terms of sampling and mass flow measurement and existing sampling and flow measurement systems, is cheaper and safer to maintain and will cost less than existing systems, whether it is fitted to a new system or to a retrofit.

[0040] In a further form of the invention, and particularly where it is desired to keep the primary conveyor 1 in alignment with the general run of belt 7, a compression belt conveyor 22 may be incorporated as shown in Figures 10 and 1 1 . The inclined compression belt conveyor 22 is provided immediately upstream of the upper roller 2 and arranged to run at the same belt speed as the primary belt conveyor 1 .

[0041 ] The compression belt conveyor has rollers 23 and 24 around which is entrained a compression belt having an upper surface 25 and an underside 26. The roller 24 is positioned just above the general run of belt 1 so that material proceeding along the belt as shown by arrow 29 passes between the primary belt in region 28 and the lower roller 24 of the compression belt conveyor such that it is compressed between the primary belt conveyor at 27 and the underside 26 of the compression belt conveyor and moved upwardly as shown by arrows 30 and 31 .

[0042] The material is then projected in an arc as indicated by arrows 32 and 33 into the bucket 8 of the falling stream sample cutter with excess material passing onwardly as shown by arrows 34 and 35 guided by curved plate 36 until it lands back on the general run of belt 7 as shown by arrow 37. [0043] This alternative configuration as has been described with reference to Figures 10 and 1 1 can also be provided with a sampling conveyor as will now be described with reference to Figures 12 and 13.

[0044] In this configuration, the sampling conveyor 38 is added into the mechanism previously described with reference to Figures 10 and 1 1 in a similar manner to the sampling conveyor 9 as previously described with reference to Figures 4 and 5. Material projected upwardly as shown by arrows 31 and 32 from the compression belt conveyor 22, rather than landing directly into the falling stream cutter bucket 8, lands on top of the sampling conveyor 38 where it may be accurately weighed by the weightometer 19.

[0045] Material issuing from the sampling conveyor 38 as shown by arrow 39 is then collected into the transversely moving cutter bucket 8 with surplus material falling as shown by arrows 40, guided by curved plate 36 as previously described.

Claims

1 . Apparatus for sampling material being conveyed on a primary belt conveyor having a general run of belt, the apparatus including an upper roller positioned beneath the belt of the conveyor and arranged to divert the belt steeply downwardly from the general run of belt, a lower roller positioned generally below the upper roller, arranged to engage the upper surface of the belt and redirect the belt to the general run of belt, and a sampler arranged to select and sample material falling from the belt as it is diverted downwardly by the upper roller.

2. Apparatus as claimed in claim 1 wherein the sampler comprises a falling-stream sample cutter having a cutter bucket arranged to traverse material falling from the belt adjacent the upper roller.

3. Apparatus as claimed in claim 1 wherein a separate sampling conveyor is provided, positioned to receive material falling from the primary belt as it is diverted downwardly by the upper roller and convey that material above the general run of belt before discharging it in a stream on to the general run of belt below, the sampler comprising a falling-stream sample cutter having a cutter bucket arranged to traverse the stream discharging from the sampling conveyor.

4. Apparatus as claimed in claim 3 wherein the sampling conveyor is wider than the primary conveyor and arranged to run at a slower speed than the primary conveyor.

5. Apparatus as claimed in either claim 3 or claim 4 wherein a weightometer is positioned beneath the belt of the sampling conveyor, arranged to weigh material passing along the sampling conveyor.

6. Apparatus as claimed in either claim 4 or claim 5 wherein an impact conveyor is provided positioned between the upper roller and the sampling conveyor and arranged to receive material falling from the belt as it is diverted downwardly by the upper roller and discharge that material on to the impact conveyor, the impact conveyor having substantially the same width as the sampling conveyor and running at substantially the same speed as the sampling conveyor.

7. Apparatus as claimed in either claim 1 or claim 2, wherein an inclined compression belt conveyor is provided immediately upstream of the upper roller arranged to run at the same belt speed as the primary belt conveyor and to compress material between the primary belt conveyor and the underside of the compression belt conveyor, projecting material upwardly into the sampler.

8. Apparatus as claimed in claim 7 wherein the inclined compression belt conveyor has a lower roller arranged to push material on the primary belt conveyor downwardly such that the primary belt is depressed into a position conforming with the general run of belt.

9. Apparatus as claimed in either claim 7 or claim 8 wherein a separate sampling conveyor is provided, positioned to receive material projected upwardly and convey that material above the general run of belt before discharging it in a stream onto the general run of belt below, the sampler comprising a falling stream sample cutter having a cutter bucket arranged to traverse the stream discharging from the sampling conveyor.

10. Apparatus as claimed in claim 9 wherein the sampling conveyor is wider than the primary conveyor and arranged to run at a slower speed than the primary conveyor.

1 1 . Apparatus as claimed in either claim 9 or claim 10 wherein a weightometer is positioned beneath the belt of the sampling conveyor, arranged to weigh material passing along the sampling conveyor.