WO2016033649A1

WO2016033649A1 - Fibre-based wear monitoring system

Info

Publication number: WO2016033649A1
Application number: PCT/AU2015/050515
Authority: WO
Inventors: Gregory John UNDERHAYES; Stephen Mark TROTMAN; John Brown; Richard William PLUMMER; Alwin NIENABER; Mark BALLER
Original assignee: Weba Australia Pty Ltd
Priority date: 2014-09-04
Filing date: 2015-09-01
Publication date: 2016-03-10

Abstract

A wear monitoring system (10) having at least one fibre cable (12) installed in a wear item (50). Each fibre cable (12) has at least one diffraction grating (16) provided along its length and each diffraction grating (16) has a set of unique light wavelengths. A signal processor (14) operates to periodically send along each fibre cable (12) at least one light signal in the set of unique light wavelengths for each diffraction grating (16) of that fibre cable (12). Each diffraction grating (16) reflects the light signal back along the fibre cable (12) to the signal processor (14) when the light signal is within its unique wavelength set. All other light signals having a wavelength not within its set of unique light wavelengths are allowed to continue along the fibre cable (12). The signal processor (14) is able to determine the level of wear applied to the wear item (50) by correlating the position of the diffraction gratings (16) associated with each reflected light signal. Also contemplated is a wear lip liner system comprising: a mount having securing means for securing the mount to a surface; a pivot mount; and a replaceable casting adapted to be releasably retained by the pivot mount, where the replaceable casting is installed and removed relative to the pivot mount by rotating a portion of the replaceable casting about the pivot mount.

Description

"FIBRE-BASED WEAR MONITORING SYSTEM"

FIELD OF THE INVENTION

[0001] The invention relates to a fibre-based wear monitoring system. The invention is particularly suited to use in mining equipment, such as wear liners and wear lip liners and an embodiment is described hereby the fibre-based wear monitoring system is embodied in a wear lip liner.

BACKGROUND TO THE INVENTION

[0002] The following discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was published, known or part of the common general knowledge in any jurisdiction as at the priority date of the application.

[0003] The construction and resource industries often use components that are designed to be replaced when worn. However, this presents the problem of knowing when such components should be replaced.

[0004] One way of determining when a worn component should be replaced is visual inspection of the component. The problem with this solution is that as the worn component is likely to form part of a working machine, the machine must be shut down before the visual inspection can be performed. This also means lost production for the time between commencing the shut down through to restarting of the machine.

[0005] To avoid the need to shut down working machines, or reduce the time spent in shut down, wear monitoring systems have been developed. Typically, these wear monitoring systems involve fastening a probe to a wear component such that the wear suffered by the wear component is also suffered by the probe. The level of wear sustained can then be determined by removing the probe through an external channel and visually inspecting the worn probe. An example of such a wear monitoring system is described in more detail in AU 2006209788 filed by Brian Investments Pty Ltd.

[0006] While such systems are an improvement, they rely on the visual accuracy of the inspectors to appropriately assess whether the worn component should be replaced or not. [0007] To avoid subjectivity in assessments, more objective electronic based systems have been developed. One example of such a system utilises the wear sensor described in WO 2010/096873 also filed by Brian Investments Pty Ltd.

[0008] WO 2010/096873 describes an electric circuit supported on a substrate. Rails bridge the two wires to complete the circuit. As each rail is worn away, the electrical conductivity of the circuit changes. By measuring such changes, the invention is able to determine the level of wear applied to the circuit and, by extrapolation, the wear component.

[0009] The problem with this approach is many, namely:

• The use of an electrical circuit means that any operational work undertaken near the sensor requires the sensor to be isolated to avoid harm coming to the operator;

• The size of the substrate requires a similar sized hole to be created in the wear component to facilitate its retention. This hole can weaken the structural integrity of the wear component and thus is not suitable for use in certain industries.

• Electrical circuits are prone to interference from the surrounding electrical environment and, when this occurs, this means that false wear readings may be provided by the sensor. As such, the sensor is again not suitable for use in certain industries.

• The level of granularity of wear able to be determined by such a system is restricted by the size of the rails used and the spacing required to be provided there between to avoid electrical interference between rails.

[0010] It is therefore an object of the present invention to provide a wear monitoring system that eliminates, or ameliorates at least in part, one or more of the aforementioned problems.

SUMMARY OF THE INVENTION

[0011] Throughout this document, unless otherwise indicated to the contrary, the terms "comprising", "consisting of", and the like, are to be construed as non- exhaustive, or in other words, as meaning "including, but not limited to". [0012] In accordance with a first aspect of the invention there is a wear monitoring system comprising: at least one fibre cable, the at least one fibre cable installed in a wear item;

each fibre cable having at least one diffraction grating provided along its length, each diffraction grating having a set of unique light wavelengths; and

a signal processor

where the signal processor operates to periodically send along each fibre cable at least one light signal in the set of unique light wavelengths for each diffraction grating of that fibre cable, such that each diffraction grating reflects the light signal back along the fibre cable to the signal processor within its unique wavelength set and lets all other light signals having a wavelength not within its set of unique light wavelengths to continue along the fibre cable and where the signal processor is able to determine the level of wear applied to the wear item by correlation of the position of the diffraction gratings associated with each reflected light signal.

[0013] In one alternative, the signal processor identifies the diffraction grating associated with a reflected light signal on its return, the signal processor thereafter operable to determine whether the identified diffraction grating has a position further away from the signal processor than all previously identified diffraction gratings that have reflected a light signal during the period since the last set of light signals were sent.

[0014] The diffraction gratings may be located at positions along the fibre cable that, when embodied in the wear item, represent specific predetermined wear levels of the wear item. Alternatively, or in conjunction, the diffraction gratings may be spaced equidistantly along the fibre cable.

[0015] In one configuration, two fibre cables are employed where the diffraction gratings of a first fibre cable are offset relative to the diffraction gratings of the second fibre cable. Preferably for this configuration, the spacing between the diffraction gratings in one cable is less than the size of the diffraction gratings in the other cable, such that each diffraction grating spans a length of the cable that is taken up in part by two other diffraction gratings in the other cable.

[0016] The signal processor may factor in the amount of wear applied to a diffraction grating in determining the level of wear applied to the wear item. The amount of wear applied to a diffraction grating may be determined by assessment of the reflected light signal's intensity.

[0017] The signal processor may be located remotely to the at least one fibre cable. Furthermore, each of the at least one fibre cable may be located within a housing.

[0018] Preferably, each set of unique light wavelengths includes light wavelengths in the range of 1500 to 1580 nm.

[0019] In accordance with a second aspect of the invention there is a wear lip liner system comprising: a mount having securing means for securing the mount to a surface; a pivot mount; and a replaceable casting adapted to be releasably retained by the pivot mount where the replaceable casting is installed and removed relative to the pivot mount by rotating a portion of the replaceable casting about the pivot mount.

[0020] The replaceable casting ideally comprises a wear plate and a pivot connector, the pivot connector operable to rotate about the pivot mount during installation and/or removal. Furthermore, in its preferred arrangement, when the replaceable casting is installed relative to the pivot mount, the weight of the wear plate positions the pivot connector about the pivot mount such that a portion of the pivot connector is firmly wedged between the mount and the pivot mount.

[0021] The replaceable casting may incorporate a wear monitoring system according to the first aspect of the invention. In one arrangement, the wear plate has a front and back and the wear monitoring system aligned so as to extend from the back to a position proximate the front of the wear plate. In an alternative arrangement, the wear plate has a top and a bottom and the wear monitoring system aligned so as to extend from the bottom to a position proximate the top of the wear plate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a first embodiment of the invention.

Figure 2 is a schematic view of a second embodiment of the invention.

Figure 3 is a schematic view of a third embodiment of the invention.

Figure 4 is a schematic view of a signal processor as used in each of the first through third embodiments of the invention.

Figure 5 is a perspective view of a wear lip liner incorporating a fibre-based wear monitoring system according to the first embodiment of the invention.

Figure 6 is a plan view showing a replaceable casting as used in the wear lip liner shown in Figure 5 in its various positions during installation of the replaceable casting.

PREFERRED EMBODIMENTS OF THE INVENTION

[0023] In accordance with a first embodiment of the invention there is a wear monitoring system 10. The wear monitoring system 10 consists of a fibre cable 12 and a signal processor 14.

[0024] The fibre cable 12 is an optical fibre cable. Located at predetermined positions along the fibre cable 12 are Fibre-Bragg diffraction gratings 16 (hereafter referred to as a FBG).

[0025] Each FBG 16 positioned along the fibre cable 12 is designed to reflect light emitted at a certain unique wavelength and allow light emitted at all other wavelengths to pass through. In doing so, each FBG 16 can be uniquely referenced by the light that it reflects back along the fibre cable 12.

[0026] In this example, each FBG 16 reflects light along the fibre cable 12 at a unique wavelength in the range of 1500 to 1580 nm.

[0027] The fibre cable 12 attaches to the signal processor 14 at one end thereof. The signal processor 14 operates at periodic intervals to send light signals, by way of a light emitter 18, at each wavelength in the 1500 to 1580 nm range mentioned above along the fibre cable 12. At the same time, the signal processor 14 operates to record the wavelengths of the light reflected back along the fibre cable 12 by way of a light receiver 20. [0028] The signal processor 14 has a memory 22 and processing unit 24.

The memory 22 stores a database 26. The database 26 holds records of each FBG 16, its position along the fibre cable 12, and the unique wavelength (in nm) that it reflects.

[0029] This embodiment of the invention will now be described in the context of its intended use.

[0030] The fibre cable 12 is embedded into a wear item 50 such that the end of the fibre cable 12 is flush with a wear surface 52 of the wear item. To ensure that the level of wear to the fibre cable 12 accurately reflects the level of wear to the wear surface 52, it is important that the fibre cable 12 be embedded in the wear surface 52 in a straight line. Preferably, this alignment of the fibre cable 12 is perpendicular to the wear surface 52.

[0031] At periodic intervals, the processing unit 24 sends a command signal

26 to the light emitter 18. On receipt of the command signal 26, the light emitter 18 operates to send a beam of light (not shown) along the fibre cable 12 in each wavelength in the range 1500 to 1580 nm.

[0032] As each beam of light travels along the fibre cable 12 it reaches at least one FBG 16. If the beam of light has a wavelength differing from the unique wavelength of the FBG 16, it passes through the FBG 16 and continues to travel down the fibre cable 12. Alternatively, if the beam of light has the same unique wavelength as that of the FBG 16, the FBG 16 operates to reflect the beam of light back towards the signal processor 14.

[0033] This process continues until all FBGs 16 that remain connected to the fibre cable 12 reflects their beam of light back towards the signal processor 14.

[0034] Each beam of light reflected back towards the signal processor 14 is received by the light receiver 20. On receipt of each beam of light, the light receiver 20 operates to determine the wavelength (in nm) of the beam of light. Once determined, the light receiver 20 communicates the wavelength (in nm) to the processing unit 24.

[0035] On receipt of the details of each wavelength (in nm) reflected, the processing unit 24 correlates the referenced wavelength with the records of the database 26. This allows the processing unit 24 to determine each FBG 16 that has reflected its unique wavelength. [0036] At the end of each periodic cycle, the processing unit 24 creates a list in memory 22 of all FBGs 16 that have reflected a beam of light. Using this list, the processing unit 24 can then determine the level of wear subjected to the fibre cable 12. By extrapolation, this also allows the signal processor 14 to determine the level of wear subjected to the wear item 50.

[0037] It is important to note that in order for the invention to work, the fibre cable 12 and its FBGs 16 must be made of a material that wears at a rate identical to or faster than the wear item 50 into which it is embedded. To do otherwise will result in the signal processor 14 providing wear indications lower than the level of actual wear subjected to the wear item 50.

[0038] It should be appreciated by the person skilled in the art that the first embodiment of the invention is particularly suited towards use in situations where determining when larger levels of wear have been reached is desired (for instance, 25%, 50% and 75% wear levels).

[0039] In accordance with a second aspect of the invention, where like numerals reference like parts, there is a wear monitoring system 100. The wear monitoring system 100 has the same components as wear monitoring system 10.

[0040] Wear monitoring system 100 also operates in the same manner as wear monitoring system 10 to emit and receive light beams. However, the processing of the reflected light beams proceeds as follows.

[0041] Each beam of light reflected back towards the signal processor 14 is received by the light receiver 20. On receipt of each beam of light, the light receiver 20 operates to determine the wavelength (in nm) of the beam of light and the intensity of the beam of light. The determined wavelength and the determined intensity of the beam of light at that wavelength is then communicated to the processing unit 24.

[0042] On receipt of the details of each wavelength (in nm) reflected, the processing unit 24 correlates the referenced wavelength with the records of the database 26. This allows the processing unit 24 to determine each FBG 16 that has reflected its unique wavelength.

[0043] At the end of each periodic cycle, the processing unit 24 creates a list in memory 22 of all FBGs that have reflected a beam of light. Using this list, the processing unit 24 can identify, by way of the location details for the record associated with each FBG 16, the FBG 16 in the fibre cable 12 furthest from the signal processor 14.

[0044] Upon identification of this FBG 16, the intensity of the beam of light reflected by this FBG 16 is used in a formula. The value provided by this formula represents the amount of the FBG 16 that has been worn away. The processing unit 24 then uses this formula value, in combination with the recorded location of the identified FBG 16 to obtain a more definitive representation of the level of wear subjected to the fibre cable 12.

[0045] Again, by extrapolation, this also allows the signal processor 14 to determine the level of wear subjected to the wear item 50.

[0046] It should be appreciated by the person skilled in the art that this second embodiment of the invention allows for a more granular representation of wear to be provided by the signal processor 14. However, this granularity only exists at the locations of the FBGs 16. Hence, the greater the number of FBGs 16 provided in the fibre cable 12, the greater the overall resolution that can be provided of the level of wear applied to a wear item 50.

[0047] In accordance with a third embodiment of the invention, where like numerals reference like parts, there is a wear monitoring system 200. The wear monitoring system 200 has two fibre cables 202a, 202b, but otherwise contains the same elements as wear monitoring system 10.

[0048] Each fibre cable 202a, 202b has a plurality of FBGs 16 spaced equidistantly along its length. As each FBG 16 also has a defined length (L), it is also important that the distance between FBGs 16 in each fibre cable 202a, 202b is less than this defined length (L).

[0049] The fibre cables 202a, 202b each connect to the signal processor 14.

Either by means of their connection to the signal processor 14, or by reason of their construction, when placed side-by-side as intended to be embedded in the wear unit 50, the FBGs 16 of fibre cable 202a are each adjacent two FBGs 16 of fibre cable 202b and vice-versa. Hence, the full length of the fibre cables 202a, 202b is the subject of at least one FBG 16. [0050] The processing of the signals received by the signal processor 14 by each fibre cable 202a, 202b then proceeds as per the second embodiment of the invention. However, for the purposes of such processing, the signals received are treated as if they have been received from a single fibre cable 202.

[0051] Using this third embodiment, it is to be appreciated that this invention allows for a granular representation of wear to be provided by the signal processor 14 along the full length of the wear item 50.

[0052] In accordance with a fourth embodiment of the invention, where like numerals reference like parts there is a lip liner 300 incorporating a fibre-based wear monitor according to either of the first or second embodiments.

[0053] The lip liner 300 comprises a mount 302 and a replaceable casting

304.

[0054] The mount 302 consists of a base plate 306. The base plate 306 may take any shape as is required to meet the requirements of its intended installation. For instance, if the lip liner 300 is designed to be used with a chute (not shown), the base plate may be horseshoe shaped as shown in Figure 5.

[0055] Positioned substantially equidistant along the base plate 306 are a pair of casting flanges 308. Each casting flange 308 extends from the base plate 306 in a direction substantially perpendicular thereto. Each casting flange 308 has an aperture 310 provided in its distal end 312, as referenced to the base plate 306.

[0056] A pivot rod 314 extends between the apertures 310 of each pair of casting flanges 308. The pivot rod 314 is welded to each aperture 310 so as to form a secure and permanent connection between the pivot rod 314 and the casting flanges 308.

[0057] Also provided equidistantly along the base plate 306 are connecting apertures 316. In this embodiment, two pairs of casting flanges 308 are positioned in between each connecting aperture 316 and its adjacent connecting aperture(s) 316.

[0058] The replaceable casting 304 comprises a wear plate 318 and a pivot connector 320. [0059] The wear plate 318 is made from a hardened material. The shape and size of the wear plate 318 is dependent on its intended install position along the base plate 306.

[0060] Extending centrally from base side 322 of the wear plate 318 is a fibre recess 324. The fibre recess 324 is of size and dimension so as to receive a fibre cable 12.

[0061] The pivot connector 320 comprises a hook portion 326 and an abutment 328. The hook portion 326 extends from the abutment 328 in a manner as will be described in more detail below. The abutment 328 is connected centrally to a rear side 330 of the wear plate 318. In this manner the fibre recess 324 is in planar alignment with the pivot connector 320.

[0062] This fourth embodiment will now be described in the context of its intended use.

[0063] The base plate 306 is placed on its intended mounting surface (not shown). The base plate 306 is then fixed to the mounting surface by the insertion of appropriate fasteners (also not shown) through connecting apertures 316.

[0064] With the base plate 306 securely fastened to the mounting surface, a replaceable casting 304 can be installed for each pair of casting flanges 308. Installation of the replaceable casting 304 commences by aligning the hook portion 326 with the pivot rod 314. In this context, alignment means manipulating the replaceable casting 304 such that an indent 332 formed between the hook portion 326 and the abutment is in contact with the pivot rod 314. This also sees the hook portion 326 take up the majority of the space between the pivot rod 314 and the base plate 306

[0065] The installer then gently lowers the wear plate 318 as the hook portion

326 itself rotates about the pivot rod 314. The pivot rod 314 remains retained within the indent 332 throughout this process. Eventually this results in the abutment 328 and the wear plate 318 making contact with floor 334.

[0066] The shape of the portion of the abutment 328 that makes contact with floor 334 is such that, when contact is made, the wear plate 318 also makes minimal contact with the floor 334. The shape of the abutment 328 as a whole also operates to properly angle the wear plate 318 relative to the floor 318. This installation process is best illustrated in Figure 6.

[0067] It is to be noted that in this position, the weight of the wear plate 318 ensure that the replaceable casting 304 is essentially maintained in this position. Furthermore, while some latitude is provided for movement along the pivot rod 314, as the hook portion 326 is now firmly wedged between the floor 334 and pivot rod 314 no provision is made for vertical movement. This also means that the replaceable casting 304 can not be removed from the structure formed by the casting flanges 38 and the pivot rod 314 without manipulation by the installer.

[0068] The wear monitoring system 10, 100 embedded into the wear plate

318 then operates as described above in a manner that wear suffered by the wear plate 318 also causes wear to the fibre. In this manner, when the fibre of the wear monitoring system 10, 100 is measured as having reduced to a predetermined wear level, or to a level the installer considers desirable for replacement, the installer then acts to remove the replaceable casting 304.

[0069] To remove a replaceable casting 304, the installer rotates the replaceable casting 304 about the pivot rod 314. When the replaceable casting 304 has been rotated approximately 90° compared to its initial starting point, free end 336 of the hook portion 326 is essentially perpendicular to the floor 334 at a position in between the pivot rod 314 and the floor 334. The replaceable casting 304 can then be freely removed by pulling the replaceable casting 304 way from the pivot rod 314. A new replaceable casting 304 can then be installed in the same manner as described above.

[0070] In accordance with a fourth embodiment of the invention, there is a lip liner (not shown) as described in the third embodiment, but omitting any fibre-based wear monitor.

[0071] It should also be appreciated by the person skilled in the art that the above invention is not limited to the embodiment described. In particular, the following modifications and improvements may be made without departing from the scope of the present invention: • [0072]The signal processor 14 may simply operate as a data recorder. When used as such, the signal processor 14 may operate to transmit, either in real-time or at periodic times, the recorded data to a remote computer system for further processing as described above. This transmission of data may also occur either on physical connection of the signal processor to the remote computer system (typically by way of a cable) or may occur through wireless transmission.

• [0073] Other wavelength ranges may be used in conjunction with the FBGs 16.

• [0074] Due to the low rate of wear of most wear items 50, the signal processor 14 may operate on long periodic intervals between sending the light signals down the fibre cable 12. However, it is possible to operate such that the light signals are sent constantly down the fibre cable 12 to provide a more "realtime" assessment of the level of wear of the wear item 50.

• [0075] Modifications of the processing of the signal processor 14 may be made without departing from the scope of this invention. For instance, the signal processor 14 may, on receipt of the reflected beam of light, determine whether the reflected beam of light represents a FBG 16 further along the fibre cable 12 than that already recorded. If so, the signal processor 14 may simply operate to record the FBG 16 associated with the reflected beam of light as the appropriate representation of current wear to the wear item 50. If not, the signal processor 14 simply disregards the reflected beam of light.

• [0076]The invention has been described in the context of determining the level of wear applied to a wear item 50. Inversely, the same processing and reasoning can be used with minor modification to determine the level of wear surface 52 remaining on the wear item 50.

• [0077] While it is preferred that the fibre cables 202 be embedded in the wear item 50 in a direction perpendicular to the wear surface 52, this need not always be the case. By appropriately adjusting the formula used to process the intensity of the beam of light, the invention should be able to be used when the fibre cables 202 are embedded in the wear item 50 at an angle to the wear surface 52. • [0078] If a wear item 50 requires an even higher level of resolution than that able to be provided by the third embodiment of the invention, even further fibre cables 202 (each having FBGs 16 offset relative to the other fibre cables 202) may be employed. Under this approach, there reaches a point where the need to assess the signal intensity of a reflected beam of light becomes immaterial as the level of wear can be determined simply by reference to those FBGs 16 in the various fibre cables 202 that are, or are not as the case may be, reflecting a beam of light.

• [0079] As the fibre cable 12, 202 is typically the size of a human hair it is prone to movement from even small forces. As this potential for movement can seriously impact on the ability to accurately set the fibre cable 12, 202 in a straight manner, the fibre cable 12, 202 may be received within a housing. The fibre cable 12, 202 may then be set straight within the housing and fixed into position by way of an epoxy resin. The housing, with fibre cable 12, 202 fixed therein, may then be fixed in place within the wear item 50. This is important as it is not possible for the fibre cable 12, 202 to be integrally formed with the wear item 50 in most cases as the temperatures required to typically forge such a wear item would destroy the fibre cable 12, 202.

• [0080]The wear monitoring system 10, 100, 200 may be installed to a predetermined depth in the wear item 50 rather than all the way through to the wear surface 52. In this manner, the wear monitoring system 10, 100, 200 may not commence monitoring of the level of wear applied to the wear item 50 until such time as a threshold level of wear has been reached. In its contemplated practical application of this approach, the wear monitoring system of the first and second embodiments of the invention only commence monitoring after the wear item 50 has been worn to eighty percent (80%) of its original condition.

• [0081]The wear lip liner of the fourth embodiment may be modified to include a fibre-based wear monitoring system according to the third embodiment as would be readily apparent to the person skilled in the art.

• [0082]The wear lip liner of the fourth embodiment may be modified such that the fibre based wear monitoring system extends from the rear side 330 through to the front 336 of each replaceable casting 304. [0083] It should be further appreciated by the person skilled in the art that the above variations and modifications, not being mutually exclusive, can be combined to form yet further embodiments that fall within the scope of the present invention.

Claims

We Claim:

1 . A wear monitoring system comprising:

at least one fibre cable, the at least one fibre cable installed in a wear item;

a signal processor

2. A wear monitoring system according to claim 1 , where the signal processor identifies the diffraction grating associated with a reflected light signal on its return, the signal processor thereafter operable to determine whether the identified diffraction grating has a position further away from the signal processor than all previously identified diffraction gratings that have reflected a light signal during the period since the last set of light signals were sent.

3. A wear monitoring system according to claim 1 or claim 2, where the diffraction gratings are located at positions along the fibre cable that, when embodied in the wear item, represent specific predetermined wear levels of the wear item.

4. A wear monitoring system according to any preceding claim, where the diffraction gratings are spaced equidistantly along the fibre cable.

5. A wear monitoring system according to any preceding claim, comprising two fibre cables where the diffraction gratings of a first fibre cable are offset relative to the diffraction gratings of the second fibre cable.

6. A wear monitoring system according to claim 5 as dependent on claim 4, where the spacing between the diffraction gratings in one cable is less than the size of the diffraction gratings in the other cable, such that each diffraction grating spans a length of the cable that is taken up in part by two other diffraction gratings in the other cable.

7. A wear monitoring system according to any preceding claim, where the signal processor factors in the amount of wear applied to a diffraction grating in determining the level of wear applied to the wear item.

8. A wear monitoring system according to claim 7, where the amount of wear applied to a diffraction grating is determined by assessment of the intensity of the reflected light signal.

9. A wear monitoring system according to any preceding claim, where the signal processor is located remotely to the at least one fibre cable.

10. A wear monitoring system according to any preceding claim, where each of the at least one fibre cable is located within a housing.

1 1 . A wear monitoring system according to any preceding claim, where each set of unique light wavelengths includes light wavelengths in the range of 1500 to 1580 nm.

12. A wear lip liner system comprising: a mount having securing means for securing the mount to a surface; a pivot mount; and a replaceable casting adapted to be releasably retained by the pivot mount where the replaceable casting is installed and removed relative to the pivot mount by rotating a portion of the replaceable casting about the pivot mount.

13. A wear lip liner system according to claim 12, where the replaceable casting comprises a wear plate and a pivot connector, the pivot connector operable to rotate about the pivot mount during installation and/or removal.

14. A wear lip liner system according to claim 13, where, when the replaceable casting is installed relative to the pivot mount, the weight of the wear plate positions the pivot connector about the pivot mount such that a portion of the pivot connector is firmly wedged between the mount and the pivot mount.

15. A wear lip liner system according to any one of claims 12 to 14, where the replaceable casting incorporates a wear monitoring system according to any one of claims 1 to 1 1 .

16. A wear lip liner system according to claim 15, as dependent on either claim 13 or claim 14, wear the wear plate has a front and back, the wear monitoring system aligned so as to extend from the back to a position proximate the front of the wear plate.

17. A wear lip liner system according to claim 15, as dependent on either claim 13 or claim 14, where the wear plate has a top and a bottom, the wear monitoring system aligned so as to extend from the bottom to a position proximate the top of the wear plate.