Our Ref: 35104850 P/00/0 I 1 Regulation 3:2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INNOVATION PATENT Applicant(s): Leonard Ian Burrell 3 Southern Street, Oatley, New South Wales 2223, Australia Address for Service: DAVIES COLLISON CAVE Patent & Trade Mark Attorneys 255 Elizabeth Street SYDNEY NSW 2000 Invention Title: "Conveyor belt weighing system with embedded tachometer" The following statement is a full description of this invention, including the best method of performing it known to me:- -1 CONVEYOR BELT WEIGHING SYSTEM WITH EMBEDDED TACHOMETER 5 Technical Field [001] The present invention generally relates to the field of conveyor belt weighing systems. More particularly, the present invention relates to a new type of tachometer and/or a conveyor belt weighing system with an embedded or integrated tachometer. 10 Background [002] Referring to Figure 1, by way of example background, there is illustrated a known conventional weigh frame 110 forming part of a belt weighing system 100. Belt weighing system 100 includes idlers (i.e. rollers) 120 spaced apart to support belt 130. Idlers 140 are part of weigh frame 110. Conveyed material, for example bulk material or process 15 material used or produced in mining or industrial processing, being transported along belt 130 imparts its weight via belt 130 and idlers 140 and can be measured by weigh frame 110. Accurate weighing is required for bulk handling of materials in many diverse industries, for example mining, ship loading, rail loading, grain, coal power, wool scouring, quarry, food and chemical industries, etc.. 20 [003] Referring to Figure 2, providing a further example as illustrative background, there is shown a section of a belt weighing system 200. Belt weighing system 200 includes a belt 210 supported by idlers 220 (which should also be read as reference to a set of grouped idlers) that are spaced apart from other belt supporting idlers. Material being 25 transported by belt 210 imparts its weight via belt 210 and idlers 220 and can be measured by a weigh frame of the belt weighing system 200. [004] There have been many approaches in attempting to develop a reliably accurate conveyor belt weighing system. One particular aspect requiring improvement involves 30 accurately determining or measuring the movement of the conveyor belt. A tachometer in this context is a device that measures the rotation of a shaft attached to a pulley or wheel in contact with the conveyor belt or directly measures the rotation of a pulley or wheel which does not have a live shaft but which is itself in contact with the conveyor belt by means of tags, flags, optical or magnetic devices attached to the rotating pulley or disk. It is known -2 to use types of tachometers in conveyor belt weighing systems. However, these known types of tachometers have disadvantages, for example they cannot be positioned within the weight sensitive zone and hence may not measure belt travel at the point of interest or may have other accuracy concerns. 5 [005] A typical conveyor belt weighing system includes, in general, a weigh frame, which measures instantaneous mass (linear density of the belt load), a tachometer which measures belt travel distance, and belt weighing system electronics/software which uses measurement data to determine, for example, belt speed, material flow rate and total 10 weight. [006] To measure conveyor belt loading a weigh frame is used to weigh a specific length of the loaded conveyor belt, termed the weigh length. This can be calibrated to take a measurement of the belt loading (e.g. in kilograms per metre). To determine an absolute 15 weight of material it is also required to measure the conveyor belt travel distance or speed. [007] Presently, to measure conveyor belt travel distance or speed a separate wheel or pulley component is placed in contact with the belt. This separate component acts as part of a tachometer. The tachometer has an electro-mechanical system such as metal tags and 20 a proximity sensor which provides a set number of pulses per meter of belt travel distance. As a result, in a set time period or distance interval, one is able to measure the distance the belt has travelled and thus the weight of material passing through the distance interval on the conveyor belt. These weights can be used to calculate a flow rate of material in appropriate units, such as tonnes per hour. 25 [008] A significant challenge in belt weighing is to make an accurate measurement of the flow rate of material on a conveyor belt. Amongst other sources of error, one important measurement requiring improved accuracy is from the tachometer. Presently known tachometers used in belt weighing systems introduce undesired errors and/or are 30 cumbersome separate components which may require a relatively high level of maintenance or calibration. Also these devices do not lend themselves to measuring belt travel in the relevant carry strand of the belt at the point of interest at the weigh frame, since they tend to misalign the conveyor belt and diminish the effectiveness of the weigh -3 frame whose role it is to accurately measure the belt loading (linear density kg/m). Misalignment to the carry strand of the belt can introduce gross errors. [009] There is a need for an improved tachometer and/or a conveyor belt weighing 5 system with an embedded or integrated tachometer which addresses or at least ameliorates one or more problems inherent in the prior art. [010] The reference in this specification to any prior publication (or information derived from the prior publication), or to any matter which is known, is not, and should not be 10 taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from the prior publication) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 15 Brief Summary of Invention [011] In general forms there is provided a tachometer and/or a conveyor belt weighing system with a tachometer, for example an embedded or integrated tachometer. [012] In an example form there is provided a conveyor belt weighing system, including: a 20 belt supported by a plurality of belt support idlers; a weigh frame associated with the belt; and, a tachometer that supports a section of the belt and is used to determine a travel distance or speed of the belt. Preferably, the tachometer is provided on a dead shaft and the tachometer has a larger diameter than at least one of the plurality of belt support idlers. 25 [013] In another example form there is provided a tachometer for supporting a section of a belt of a conveyor belt weighing system having a plurality of belt support idlers, where the tachometer is provided on a dead shaft and is able to be positioned next to a belt support idler and the tachometer has a larger diameter than the belt support idler. 30 [014] In another example form there is provided a conveyor belt weighing system, including: a belt, for conveying material, associated with a weigh frame; the weigh frame able to measure a belt weight of a section of the belt; and an embedded or integrated tachometer able to determine a travel distance or speed of the belt.
-4 [015] Preferably, the tachometer at least partially supports the belt. In various forms, the tachometer is used in place of a belt support idler, the tachometer can also perform the function of a belt support idler, and/or the tachometer can be positioned in place of a belt support idler. 5 [016] In a particular form, the tachometer thus performs a dual role, functioning as a carry roller or idler as well as a tachometer. In one example form, the tachometer is provided on a dead shaft, i.e. not a driven shaft. Preferably, this provides the tachometer with very low inertia and rolling resistance. 10 [017] In another example aspect, the tachometer can be height adjustable, with respect to the belt, for alignment purposes. In another aspect, the tachometer has a larger diameter than a normal roller or idler which reduces any errors arising from variations in diameter. 15 [018] Advantages arise in various embodiments due to the relatively large diameter of the tachometer. For example, the surface area of belt in contact with the tachometer, acting as a roller, is increased and hence the indentation in the belt caused by the tachometer is reduced and any variability in turning characteristic is also reduced. Any variability in turning radius is also reduced when compared to a normal carry roller due simply to the 20 larger radius which can change in percentage by typically 1/2 as much as would a roller of normal carry diameter. [019] In some manifestations the tachometer roller could be spring loaded so as to maintain a fixed force between the belt and the tachometer roller. The spring loading 25 would ensure that indentation effects would remain constant. [020] The tachometer roller could have an engraved or embossed surface pattern to permit accurate operation in the presence of a wet belt. The roller assembly might also incorporate a cleaner or scraper to assist with keeping the roller clean. 30 [021] According to still further examples aspects, more than one tachometer can be included in the conveyor belt weighing system. For example, a tachometer could be embodied as a tachometer roller that helps support the belt, and be positioned on either -5 side of a weigh frame. Thus, two tachometers can be utilised in a dual redundant pair improving the reliability of the system. Brief Description Of Figures 5 [022] Example embodiments should become apparent from the following description, which is given by way of example only, of at least one preferred but non-limiting embodiment, described in connection with the accompanying figures. [023] Figure 1 (prior art) illustrates an example known weigh frame; 10 [024] Figure 2 (prior art) illustrates an example known conveyor belt weighing system; [025] Figure 3 illustrates an example conveyor belt weighing system with an embedded or integrated tachometer; 15 [026] Figure 4 illustrates a top view, side view and end view of an example conveyor belt weighing system with embedded or integrated tachometers; [027] Figure 5 illustrates a top view, side view and end view of a section of an example 20 conveyor belt weighing system which includes an embedded or integrated tachometer; [028] Figure 6 illustrates an example processing system that can be used as part of the belt weighing system; 25 [029] Figure 7 illustrates an example tachometer roller positioned on a frame; [030] Figure 8 illustrates an example tachometer roller; [031] Figure 9 illustrates another example tachometer roller; 30 [032] Figure 10 illustrates an example tachometer roller positioned on a frame near winged rollers; -6 [033] Figure 11 illustrates a close-up view of the example tachometer roller of Figure 10. Preferred Embodiments [034] The following modes, given by way of example only, are described in order to 5 provide a more precise understanding of the subject matter of a preferred embodiment or embodiments. In the figures, incorporated to illustrate features of an example embodiment, like reference numerals are used to identify like parts throughout the figures. [035] In a particular embodiment there is provided a belt weighing system, comprising a 10 belt, for conveying material, associated with a weigh frame. The weigh frame is able to measure a weight for a section of the belt. Example weigh frames include fully suspended weigh frames, dual pivoted "approach-retreat" type weigh frames, amongst others, that are known in the art. At least one tachometer, preferably an embedded or integrated tachometer, is also provided that is able to determine a travel distance of the belt. 15 Preferably, the tachometer supports a section of the belt. Also preferably, the tachometer may perform the function of a belt support idler, and/or the tachometer may be positioned in place of a belt support idler. [036] Referring to Fig. 3, there is illustrated a conveyor belt weighing system 300 20 comprising a belt 310 for conveying material, associated with a weigh frame 330. Belt 310 is supported by rollers (i.e. idlers) 320. Weigh frame 330 is able to measure a belt weight of a section of the belt 310. Also included is an embedded, i.e. integrated, tachometer 340 used to determine or measure a travel distance or speed of belt 310. Tachometer 340 also supports a section of belt 310. 25 [037] One or more tachometers may be provided as various locations as embedded or integrated in conveyor belt weighing system 300, for example on either side of a weigh frame, and/or as part of the weigh frame 330 itself. Tachometer 340 can also perform the supporting function of a normal roller 320. Thus, tachometer 340 preferably performs a 30 dual role, that of a carry or support roller 320 in addition to a tachometer function. Preferably, tachometer 340 can be positioned in place of a belt support roller 320.
-7 [038] Tachometer 340 is preferably provided on a dead shaft, that is not a driven shaft. This provides the tachometer roller 340 with very low inertia and rolling resistance. The dead shaft can be selectively positioned so that tachometer 340 is height adjustable for alignment purposes. Tachometer 340 has a larger diameter than a normal support roller 5 320. A larger diameter means that any error from variations in diameter is reduced or minimised. In one particular example, tachometer 340 is preferably at least 200mm in diameter. A typical example size for tachometer 340 might be 300mm in diameter, although the diameter can be substantially varied depending on the specific function or application of different conveyor belt weighing systems. 10 [039] Referring to Fig. 4 there is illustrated further details of an example conveyor belt weighing system 400 with tachometer rollers 410 positioned on either side of a weigh frame 420. Fig. 4 illustrates a top view, side view and end view of conveyor belt weighing system 400 and an enlarged end view of a tachometer roller 410. The number, spacing and 15 dimensions of normal support rollers/idlers 430 and tachometer rollers 410 can be varied depending on the specific implementation of conveyor belt weighing system 400. Tachometer roller 410 includes dead shaft 440. Known sensor systems can be used to measure the number or frequency of rotations of tachometer roller 410. For example, a type of marker (e.g. visible or metallic) can be provided on an end surface of tachometer 20 roller 410 where passage of the marker is sensed by a sensor to determine the number of revolutions, or partial revolutions, of tachometer roller 410. A variety of known sensor systems can be used, such as light based sensing systems, magnetic based sensing systems, electromagnetic based sensing systems, or a variety of other proximity sensing systems. 25 [040] Referring to Fig. 5, there is illustrated a section 500 of an example conveyor belt weighing system that includes a tachometer roller 510 positioned in an assembly frame 520 that also supports normal carry or support rollers 530. This illustrates how tachometer roller 510 is of larger diameter than a normal carry roller 530 and can be positioned in place of a normal carry roller. Tachometer roller 510 is shown to be height adjustable for 30 alignment purposes with adjacent carry rollers 530. Specific dimensions and spacing is illustrative only and can be significantly varied.
-8 [041] At least one processor, which may be dedicated processing electronics, a microprocessor, a custom built electronics system, a programmed general purpose processing system or computer, etc., can be provided and is able to determine the speed or travel distance of the belt based on measurements or data from the tachometer or multiple 5 tachometers. [042] A particular embodiment can use a processing system, or dedicated microprocessor, an example of which is shown in Figure 6. The processing system 600 generally includes at least one processor 602, or processing unit or plurality of processors, 10 memory 604, at least one input device / interface 606 (e.g. interfaced to the one or more tachometers and/or the weigh frame) to receive input data 618 and at least one output device 608, coupled together via a bus or group of buses 610. At least one storage device 614 which houses at least one database 616 can also be provided, locally or remotely. The memory 604 can be any form of memory device, for example, volatile or non-volatile 15 memory, solid state storage devices, magnetic devices, etc. The processor 602 could include more than one distinct processing device, for example to handle different functions within the processing system 600. [043] Output device 608 produces or generates output data 620 and can include, for 20 example, a display device or monitor in which case output data 120 is visual, a port for example a USB port, a peripheral component adaptor, a data transmitter or antenna such as a modem or wireless network adaptor, etc. A user could view data output, or an interpretation of the data output, on, for example, a monitor. The storage device 614 can be any form of data or information storage means, for example, volatile or non-volatile 25 memory, solid state storage devices, magnetic devices, etc. [044] In use, the processing system 600 is adapted to allow speed, number of revolutions or distance data, etc., received from the tachometer or associated sensor as input data 618 to be stored in and/or retrieved from, via wired or wireless communication means, the 30 memory 604 and/or the at least one database 616. Processed results can be displayed to a user by utilising output device 608. More than one input device 606 and/or output device 608 can be provided. It should be appreciated that the processing system 600 may be any form of microprocessor, computer, specialised hardware, or the like. The processing -9 system 600 may be a part of a networked communications system. Output data 620 can include or represent, for example, the actual adjusted weight of material, the flow rate of material and/or one or more control signals or indications of the weighing system functions, e.g. the belt is in an empty state, a zero adjustment was made, belt speed, an 5 alarm, a measure of precision, etc. [045] Referring to Fig. 7, there is illustrated an example tachometer roller 700 having a cylindrical surface 710 and positioned on an assembly frame 730 that also supports normal carry or support rollers. Tachometer roller 700 is of larger diameter than a normal carry 10 roller and can be positioned in place of a normal carry roller. Tachometer roller 700 includes dead shaft 720 that is supported in or by bracket(s) 740 at either end of dead shaft 720. The dead shaft 720 can be positioned and held at different heights in bracket(s) 740 so that tachometer roller 700 is height adjustable for alignment purposes with adjacent carry rollers. Sensor system 750 measures rotational movement of tachometer roller 700. 15 A variety of known sensor systems can be used. Referring to Fig. 8, tachometer roller 700 is shown removed from assembly frame 730 and bracket(s) 740. [046] Referring to Fig. 9 there is illustrated another example tachometer roller 900. Referring to Fig. 10 there is illustrated example tachometer roller 900 positioned on a 20 frame component 910 near winged rollers 920. Referring to Fig. I there is illustrated a close-up view of the example tachometer roller 900 shown in Fig. 10. The tachometer roller 900 is supported by brackets 930 and is height adjustable. Sensor 940 can measure rotational movement of tachometer roller 900. 25 [047] Optional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated 30 herein as if individually set forth.
- 10 [048] Although a preferred embodiment has been described in detail, it should be understood that various changes, substitutions, and alterations can be made by one of ordinary skill in the art without departing from the scope of the present invention. 5