AU2009200658A1

AU2009200658A1 - A wear indicating apparatus and a method of indicating wear of a wear plate

Info

Publication number: AU2009200658A1
Application number: AU2009200658A
Authority: AU
Inventors: Ronald Graham Bevan
Original assignee: CQMS Pty Ltd
Current assignee: CQMS Pty Ltd
Priority date: 2008-02-26
Filing date: 2009-02-19
Publication date: 2009-09-10
Anticipated expiration: 2029-02-19
Also published as: AU2009200658B2

Description

P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "A WEAR INDICATING APPARATUS AND A METHOD OF INDICATING WEAR OF A WEAR PLATE" The following statement is a full description of this invention, including the best method of performing it known to me/us: 1 TITLE A WEAR INDICATING APPARATUS AND A METHOD OF INDICATING WEAR OF A WEAR PLATE 5 FIELD OF THE INVENTION The invention relates to a wear indicating apparatus for a wear plate and to a method of indicating wear of the wear plate. In particular, although not exclusively, the invention relates to a wear indicating apparatus and a method of indicating wear to indicate whether or not the 10 wear plate has worn down to a reflective surface set in the wear plate. BACKGROUND TO THE INVENTION Wear plates are employed for wear protection in a variety of applications such as in chutes, hoppers, bins, impact walls and screen plates. As wear plates are designed to be worn away, they need periodic 15 replacement. Planning the replacement of wear plates is made difficult by the fact that, traditionally, the wear plates could only be inspected for excessive wear during times of shut down to allow for manual inspection of the wear plates. Manual inspection of wear plates may include maintenance personnel working in dangerous environments, such as a 20 chute, which is a safety concern. Failure of the wear plates during use due to lack of warning of impending failure is also of concern. Attempts have been made to measure the wear of wear plates in real-time by, for example, embedding a plug into a wear plate which is flush with the outer wear surface of the wear plate. The plug wears away 2 at the same rate as the wear plate and the thickness of the wear plate is determined by measuring the thickness of the plug using laser technology. OBJECT OF THE INVENTION It is an object of the invention to overcome or at least alleviate one 5 or more of the above problems and/or provide the consumer with a useful or commercial choice. It is a further object of the invention to provide a robust wear indicating apparatus and method to indicate whether or not the wear plate has worn down to a predetermined depth at which a reflective surface is 10 set. DISCLOSURE OF THE INVENTION In one form, although it need not be the only or indeed the broadest form, the invention resides in a method of indicating wear of a wear plate, the method including: 15 emitting light directed at a reflective surface in the wear plate from a non-wearing side of the wear plate, wherein the wear plate has a predetermined thickness measured between the reflective surface and a wear side of the wear plate; determining whether the wear plate has worn down to the reflective 20 surface by sensing if light is reflected from the reflective surface; and indicating when the wear plate has worn down to the reflective surface. Preferably, the method includes activating an alarm to indicate that the wear plate has worn down to the reflective surface.

3 In another form, the invention resides in a wear indicating apparatus including: a light generator which is operable to generate light which is directed at a reflective surface in a wear plate along a first optical path 5 from a non-wearing side of the wear plate; a light sensor which is operable to sense reflected light which is reflected from the reflective surface along a second optical path; and an indicator connected to the light sensor and operable to indicate when the light sensor senses light and when it does not; 10 wherein, in use, the light from the light generator is reflected from the reflective surface so as to be sensed by the light sensor, thereby to indicate via the indicator that the reflective surface is intact and as such the wear plate has not as yet worn down to the reflective surface. Preferably, the first optical path is an emitting optic fibre which is 15 connected to the light generator at a proximal end and which terminates adjacent the reflective surface at its distal end and via which light generated by the light generator is transmitted to the reflective surface. Preferably, the second optical path is a receiving optic fibre which is connected to the light sensor at its proximal end and which terminates 20 adjacent the reflective surface at its distal end and via which light reflected from the reflective surface is transmitted to the sensor. Preferably, the indicator is in the form of an alarm. In yet another form, the invention resides in a wear plate which has a recess defined therein which extends from a non-wearing side of the 4 wear plate to a reflective surface at a terminating end of the recess, wherein the wear plate has a predetermined thickness measured between the reflective surface and a wear side of the wear plate. Preferably, the recess is in the form of a hole which is dimensioned 5 to receive the distal ends of optic fibres therein. In still another form, the invention resides in a wear plate system comprising: a wear plate having a hole defined therein which extends from a non-wearing side of the wear plate to a reflective surface at a terminating 10 end of the hole, wherein the wear plate has a predetermined thickness measured between the reflective surface and a wear side of the wear plate; and the wear indicating apparatus as described and defined hereinabove for indicating when the wear plate has worn down to the 15 reflective surface. Further features of the present invention will become apparent from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS To assist in understanding the invention and to enable a person 20 skilled in the art to put the invention into practical effect, preferred embodiments of the invention will be described by way of example only with reference to the accompanying drawings, wherein: FIG 1 shows a front view of a wear indicating apparatus according to the second aspect of the invention; 5 FIG 2 shows a perspective view of wear plate for use with the wear indicating apparatus of Figure 1; and FIG 3 shows a front view of the wear indicating apparatus of Figure 1 in use with the wear plate of Figure 2. 5 DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1 of the drawings, a wear indicating apparatus in accordance with the invention is designated generally by reference numeral 10. The wear indicating apparatus 10 comprises a monitoring unit 12, an emitting optic fibre 14 and a receiving optic fibre 16. 10 The optic fibres 14, 16 are connected to the monitoring unit 12 at their proximal ends and terminate at their distal ends 18. The wear indicating apparatus 10 is for use with a wear plate 30 (shown in Figure 2) to indicate when the wear plate 30 has worn through a predetermined thickness of the wear plate. 15 The monitoring unit 12 includes a housing 20 in which a light generator (not shown) and a light sensor (not shown) is housed. Six input/output plug connectors 22 are located in the housing 20. The proximal ends of the pair of optic fibres 14, 16 plug into one of these connectors 22. The monitoring unit 12 also includes an indicator in the 20 form of a light emitting diode (LED) lamp 24 mounted on top of the housing 20. In use, the light generator of the monitoring unit 12 is operable to generate a light which is transmitted through the emitting optic fibre 14 along a first optical path. The sensor of the monitoring unit 12 is able to sense light received via the receiving optic fibre 16 from its distal 6 end 18, along a second optical path. The monitoring unit 12 further includes a programmable logic controller (PLC), not shown, connected to the light generator, light sensor and LED lamp 24. The PLC is programmed to energize the LED lamp 24 5 in a flashing sequence when light at the distal end 18 of the receiving optic fibre 16 is not sensed in response to light emitted from the distal end 18 of the optic fibre 14. Conversely, the LED lamp 24 is not energized when light in the receiving optic fibre 16 is sensed in response to light emitted from the emitting optic fibre 14. 10 With reference to Figure 2 of the drawings, each wear plate 30 comprises a mild steel backing layer 30.1 and a wear layer 30.2 of chromium/molybdenum white iron or any suitable wear resistant material. The wear layer 30.2 is, for example, three times as thick as the backing layer 30.1. Each wear plate 30 has an outer wear side 28 on the outside 15 of the wear layer 30.2, and a non-wearing side 34 on the outside of the backing layer 30.1. Each wear plate 30 has a recess in the form of a hole 32 defined therein which extends into the wear plate from the non-wearing side 34. A reflective surface 36 is defined on the terminating surface at the back of the hole 32 at a predetermined thickness measured between 20 the reflective surface 36 and the outer wear side 28. The reflective surface 36 is at a depth of the wear plate 30 where the wear plate is ready to be replaced when the wear plate is worn down to the reflective surface 36. The hole 32 is dimensioned to snugly receive the distal ends 18 of the emitting and receiving optic fibres 14, 16 therein. The distal ends 18 of 7 the optic fibres 14, 16 terminate adjacent the reflective surface 36 at the back of the hole 32. As such, light that is emitted via the emitting optic fibre 14 is reflected from the reflective surface 36 and into the receiving optic fibre 16. It must be appreciated that when the reflective surface 36 5 disintegrates and is no longer intact, light from the emitting optic fibre 14 does not reflect back into the receiving optic fibre 16. Figure 3 shows a wear plate system 100 comprising the wear indicating apparatus 10 and wear plates 30 mounted to a chute wall 40. The optic fibres 14, 16 extend through a hole in the chute wall 40 and are 10 received in the hole 32 from the non-wearing side of one of the wear plates 30. In use, light generated by the light generator in the monitoring unit 12 is transmitted to the reflective surface 36 via the emitting optic fibre 14. If the reflective surface 36 is intact, the light is reflected into the receiving 15 optic fibre 16. The reflected light is then transmitted to the sensor of the monitoring unit 12 via the receiving optic fibre 16. As discussed hereinabove, the logic of the PLC is such that when light is sensed in response to light being transmitted it is determined that the reflective surface 36 is still intact and the LED lamp 24 will not be energized. As 20 soon as the wear plate 30 wears down to the reflective surface 36, the reflective surface 36 disintegrates and light is no longer be reflected thereby so that no light is sensed by the sensor in response to light transmitted by the emitting optic fibre 14. As such, the PLC will then determine that the wear plate has worn down to the reflective surface 36 8 and energize the LED lamp 24 in a flashing sequence. The illumination of the LED lamp 24 is meant to alert operators to the wear condition of the wear plate 30. The wear indicating apparatus 10 is able to give reliable indication 5 when the wear plates 30 have reached the end of their useful life and need to be changed. Generally the reflective surface 36 is set at a depth so that it disintegrates when the wear layer 30.2 of the wear plate 30 has worn away 90% of its thickness, but it may be set at any variable depth depending on requirements. This allows sufficient time for new wear 10 plates to be ordered and replaced during normal maintenance shutdown periods. The wear indicating apparatus 10 is able to monitor up to six wear plates 30 remotely from a single monitoring unit 12 by plugging in further pairs of optic fibre to the connectors 22. The use of fibre optics instead of traditional electronic sensing equipment makes the wear 15 indicating apparatus 10 very robust. Throughout the specification the aim has been to describe the invention without limiting the invention to any one embodiment or specific collection of features. Persons skilled in the relevant art may realize variations from the specific embodiments that will nonetheless fall within 20 the scope of the invention. For example, the LED lamp may be replaced by a wireless communication module that is operable to alert someone remotely that a wear plate has worn down to the predetermined thickness. Similarly, any other means may be used to raise alarm that the wear plate has worn down to the predetermined thickness.

9 It will be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit and scope of the invention. In another embodiment of the invention, not illustrated, a wear 5 indicating system comprises the wear plate 30 as defined and described hereinabove, a light sensor, an indicator in the form of an audible alarm and an optic fibre which extends between the hole 32 and the light sensor. In use, the hole 32 is dark whilst the wear plate 30 has not yet worn to the reflective surface 36 and no light is sensed by the light sensor. When the 10 wear plate 30 wears down to the reflective surface 36, the hole becomes open form the outer wear side 28 and light penetrates the hole from the outer wear side. As such, the light sensor senses light and the alarm is sound to indicate that the wear plate has worn down to the reflective surface 36.

Claims

1. A method of indicating wear of a wear plate, the method including: emitting light directed at a reflective surface in the wear plate from a non-wearing side of the wear plate, wherein the wear plate has a predetermined thickness measured between the reflective surface and a wear side of the wear plate; determining whether the wear plate has worn down to the reflective surface by sensing if light is reflected from the reflective surface; and indicating when the wear plate has worn down to the reflective surface.

2. The method of claim 1, wherein the method includes activating an alarm to indicate that the wear plate has worn down to the reflective surface.

3. A wear indicating apparatus including: a light generator which is operable to generate light which is directed at a reflective surface in a wear plate along a first optical path from a non-wearing side of the wear plate; a light sensor which is operable to sense reflected light which is reflected from the reflective surface along a second optical path; and an indicator connected to the light sensor and operable to indicate when the light sensor senses light and when it does not; 11 wherein, in use, the light from the light generator is reflected from the reflective surface so as to be sensed by the light sensor, thereby to indicate via the indicator that the reflective surface is intact and as such the wear plate has not as yet worn down to the reflective surface.

4. The wear indicating apparatus of claim 3, wherein the first optical path is an emitting optic fibre which is connected to the light generator at a proximal end and which terminates adjacent the reflective surface at its distal end and via which light generated by the light generator is transmitted to the reflective surface.

5. The wear indicating apparatus of claim 3 or claim 4, wherein the second optical path is a receiving optic fibre which is connected to the light sensor at its proximal end and which terminates adjacent the reflective surface at its distal end and via which light reflected from the reflective surface is transmitted to the sensor.

6. The wear indicating apparatus of any one of claims 3 to 5, wherein the indicator is in the form of an alarm.

7. A wear plate which has a recess defined therein which extends from a non-wearing side of the wear plate to a reflective surface at a terminating end of the recess, wherein the wear plate has a predetermined thickness 12 measured between the reflective surface and a wear side of the wear plate.

8. The wear plate of claim 7, wherein the recess is in the form of a hole which is dimensioned to receive the distal ends of optic fibres therein.

9. A wear plate system comprising: a wear plate having a hole defined therein which extends from a non-wearing side of the wear plate to a reflective surface at a terminating end of the hole, wherein the wear plate has a predetermined thickness measured between the reflective surface and a wear side of the wear plate; and the wear indicating apparatus of any one of claims 3 to 6 for indicating when the wear plate has worn down to the reflective surface.