AU2014200336A1 - Sensor and uses thereof - Google Patents

Abstract

- 20 A sensor for determining wear in a material such as a wear plate or liner of a chute in a conveyor system. The sensor comprises a plurality of layered RFID chips and respective antennae. In situ, the RFIP chips locate across the thickness of the material. The extent 5 of wear of the material can be determined via interrogation of the functional state of the chips. The inclusion of multiple sensors in different locations across/along the material enables determination of a wear profile associated with the material. Figu

Description

Regulation 3.2 AUSTRALIA PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: STUART JAMES TERRELL AND LAMBERT HENDRIK DE KOCK Actual Inventors: TERRELL, Stuart James; De KOCK, Lambert Hendrik Address for service AJ PARK, Level 11, 60 Marcus Clarke Street, Canberra ACT in Australia: 2601, Australia Invention Title: Using RF To Determine Wear The following statement is a full description of this invention, including the best method of performing it known to me.

-2 FIELD OF THE INVENTION The invention relates to a sensor and the use of RFID (Radio Frequency Identification) devices to measure or determine a change in the particular environment remotely. For example, the sensor of the present invention relates to the use of RFID 5 devices to determine wear on conveyor belt systems used in product transfer chutes. BACKGROUND OF THE INVENTION Determining a critical change in a particular environment when direct access to that environment is restricted due to position or the hazardous nature of the environment or when measurement is not commercially viable is a problem that spans multiple 10 industries. Existing measurement devices require a power source and are normally prohibitively expensive to purchase/install and maintain. Changes in the environment for this invention are wear or degradation of the host material. One example is for product transfer between conveyors is normally performed through a number of chutes. As the product passes through the chutes there is abrasive 15 wear at points where the product impacts upon, and slides on, the chute surfaces. Chute designers provide for abrasive wear in chutes by using abrasive resistant plates to line the inside of the chute. These are commonly referred to as wear plates. The wear rate of the wear plates depends on the type of product, its abrasive index as 20 well as the volume of product passing through the chute. Also, the friction coefficient between the product and the chute lining material is not a constant; it increases with reduced depth of flow in the chute, and changes with variations in moisture content. The friction coefficient may also include a velocity dependent, or viscous, component. The velocity of flow down an inclined surface will affect the level of abrasion of the wear 25 surface. The rate of erosion is approximately related to the square of the velocity. Because of changes in the process, product feed is not always constant and the speeds of the conveyors change. Doubling the velocity of the product down the chute approximately increases the wear by a factor of four. Sooner or later the wear plates or liner material will have to be 30 replaced. However, it is extremely difficult to accurately calculate the wear rates of the wear liners. Currently, the most common method to determine wear liner condition and wear is by inspecting the wear liners inside the chutes at predetermined intervals. The frequency of these inspections is chosen to allow for scheduled 35 wear plate replacement before damage to the chute material or structure occurs.

-3 Inspection of the chute must be performed by specialized personnel. The product transfer process must be shut down and the inside of the chutes emptied and cleaned. Access to the inside of chutes is difficult and "confined space permits "and stand-by personal may be required. Also, there is a high risk involved for the personnel 5 conducting chute inspections. Therefore there is a need in the art for solutions that can overcome the above problems. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved or at 10 least an alternative sensor that will provide an indication of wear. In a first aspect the invention may broadly be said to consist in a sensor for use to provide an indication of wear, said sensor comprising: a plurality of RFID chips layered one upon the other, a respective plurality of antennae, each connected to a respective one of said 15 plurality of RFID chips, an outer body encapsulating said plurality of RFID chips and said respective plurality of antennae. Preferably said plurality of RFID chips and said respective plurality of antennae are first encapsulated in a wear medium that is then encapsulated in said outer body. 20 Preferably said outer body is of a material that in use will wear at a similar rate to the wear material that the sensor is fixed to in use. Preferably the sensor is an elongated tubular member. Preferably the outer body is an elongated tubular member. Preferably said plurality of RFID chips are disposed at one end of said elongated 25 tubular member. Preferably said plurality of antennae are disposed at the other end of said elongated tubular member. Preferably each of said plurality of RFID chips is a high frequency chip. Preferably each of said plurality of RFID chips is an ultra high frequency chip. 30 In a second aspect the invention may broadly be said to consist in a sensor for use to provide an indication of wear, said sensor comprising: at least one RFID chip, at least one antenna connected to said at least one RFID chip, an outer body encapsulating said at least one RFID chip and said at least one 35 antenna.

-4 Preferably said at least one RFID chip and said at least one antenna are encapsulated in a wear medium that is then encapsulated in said outer body. Preferably said at least one RFID chip is a plurality of RFID chips layered one upon the other. 5 Alternatively said at least one RFID chip is a plurality of RFID chips placed is sideways relation with each other. Preferably said at least one antenna is a plurality of antenne, each of said plurality associated with one of said plurality of RFID chips. Preferably said outer body is of a material that in use will wear at a similar rate 10 to the wear material that the sensor is fixed to in use. Preferably the sensor is an elongated tubular member. Preferably the outer body is an elongated tubular member. Preferably said at least one RFID chip is disposed at one end of said elongated tubular member. 15 Preferably said at least one antenna is disposed at the other end of said elongated tubular member. Preferably said at least one RFID chip is a high frequency chip. Preferably said at least one RFID chip is an ultra high frequency chip. In a third aspect the invention may broadly be said to consist in a system to 20 determine the wear of a material comprising: a plurality of RFID sensors, including at least one RFID chip and respective antenna, said plurality of RFID sensors capable in use of being embedded in a material to which wear is to be monitored, at least one transmitter capable of communicating with and interrogating each of 25 said plurality of RFID sensors, a computer or processor connected to said transmitter collecting data from said transmitter, said computer capable of creating a wear profile of said material being monitored. Preferably said system includes a graphical user display connected to the 30 computer to enable display of the wear profile. Preferably said wear profile provides a rate of wear of said material. Preferably said wear profile provides a representation of a percentage of wear of said material across its thickness. Preferably said wear profile provides a representation of a percentage of wear of 35 said material across the surface of the material.

- 5 Preferably said wear profile provides a wear pattern across the surface of said material. In a fourth aspect the invention may broadly be said to consist in a method of determining wear of a wear plate or liner comprising the steps of: 5 encapsulating a layered RFID sensor in said wear plate or liner, said sensor having a plurality of RFID chips layered one upon the other, a respective plurality of antennae, each connected to a respective one of said plurality of RFID chips, an outer body encapsulating said plurality of RFID chips and said respective plurality of antennae, recording details of the position of each of said RFID sensor and each of said 10 RFID chips in said wear plate or liner, communicating with each of said plurality of RFID chips with a transmitter, determining when one of said RFID chips has been damaged due to wear, correlating said damaged RFID chips position with the recorded details, creating a wear profile associated with wear of said wear plate or liner based on 15 communication or lack of communication with each of said plurality of RFID chips. Preferably said wear profile provides a rate of wear of said wear plate or liner. Preferably said wear profile provides a representation of a percentage of wear of the wear plate or liner across its thickness. Preferably said wear profile provides a representation of a percentage of wear of 20 the wear plate or liner across the surface of a wear plate or liner. Preferably said wear profile provides a wear pattern across the surface of said wear plate or liner. In a fifth aspect the invention may broadly be said to consist of a sensor for use to provide an indication of wear, said sensor comprising: 25 at least one RFID chip, at least one antenna connected to said at least one RFID chip, an outer body encapsulating said at least one RFID chip. Preferably said at least one RFID chip is encapsulated in a wear medium, and wherein the wear medium is encapsulated in said outer body. 30 Preferably said sensor is adapted to fix to a material in use to provide an indication of wear of the material, and wherein the outer body is of a material that in use will wear at a similar rate to the material that the sensor is adapted to fix to. Preferably the sensor is an elongate member. Preferably the outer body is an elongate member. 35 Preferably said at least one RFID chip is disposed at one end of said elongate member.

-6 Preferably said at least one antennae are disposed at an opposing end of said elongated tubular member to the respective RFID chips. Preferably the at least one RFID chip and the at least one antennae are encapsulated by the outer body. 5 Preferably said at least one RFID chip is a high frequency chip. Preferably said at least one RFID chip is an ultra high frequency chip. Preferably the sensor further comprises a plurality of RFID chips and a plurality of antennae, each antenna being connected to an associated RFID chip. 10 Preferably the plurality of RFID chips are layered one upon the other. Preferably the plurality of antennae are layered one upon the other. In a sixth aspect the invention may broadly be said to consist of a system to determine the wear of a material comprising: at least one wear sensor, including at least one RFID chip and at least one 15 antenna, each wear sensor capable in use of being embedded in a material to which wear of the material is to be monitored. Preferably the sensor further includes a body encapsulating the at least on RFID chip. Preferably the system further comprises: 20 at least one transceiver capable of sending an interrogation signal to the at least one wear sensor and capable of receiving a response signal from the at least one wear sensor in response to interrogation, and at least one processor communicatively coupled to said transceiver and adapted to initiate transmission of said interrogation signal and determine a condition of wear of 25 each of the at least one wear sensor from the interrogation. Preferably the at least one processor is adapted to interrogate a functional state of each of the at least one RFID chip of each of the at least one wear sensor by initiating transmission of one or more interrogation signals to each of the at least one wear sensor, and is further adapted to determine a condition of wear of the wear sensor by 30 determining a functional state of each associated RFID chip based on presence or absence of a response signal from the RFID chip. Preferably each of the at least one wear sensor comprises a pluarity of RFID chips layered one upon the other and each of the at least one sensor is embedded across a thickness of the material to dispose the RFID chips across the thickness of the material.

-7 Preferably the at least one processor is adapted to generate a wear profile across a thickness of the material based on the condition of wear of at least one of the wear sensors. Preferably said wear profile includes a representation of a percentage of wear of 5 said material across a thickness of the material. Preferably said at least one processor is adapted to generate a wear profile including a representation of a percentage of wear of said material across a surface of the material based on the indication of wear of each of the one or more wear sensors and a relative position of the wear sensor along the surface of the material. 10 Preferably said wear profile includes a wear pattern across a surface of said material. Preferably the system further comprises a graphical user display connected to the processor to enable display of the wear profile to a user. Preferably the material to which wear of the material is to be monitored is a wear 15 plate or liner of a conveying medium. Alternatively the material to which wear of the material is to be monitored is a conveyor belt. In a seventh aspect the invention may broadly be said to consist of a method of determining wear of a material comprising the steps of: 20 encapsulating at least one wear sensor in said material, said sensor having at least one RFID chip, and at least one antennae connected to the at least one RFID chip, recording information relating to a relative position of each of the at least one wear sensors in or along said material, interrogating each of said plurality of RFID chips of at least one wear sensor via 25 a transceiver, determining a wear profile associated with the material based on a response to the interrogation of each of the plurality of RFID chips of the at least one sensor and the relative position of the sensor. Preferably each of the at least one wear sensor comprises a pluarity of RFID 30 chips layered one upon the other and each of the at least one sensor is embedded across a thickness of the material to dispose the RFID chips across the thickness of the material. Preferably the step of determining a wear profile comprises: determining, for each RFID chip of the at least one sensor, a functional state of the chip, 35 determining a wear condition of the material at each relative position of each sensor along the material, and -8 generating a wear profile associated with wear of said material based on the wear condition at each relative position along the material. Preferably each wear sensor further includes an outer body encapsulating said at least one RFID chip of the sensor. 5 Preferably the material is a wear plate or a liner of a conveying medium. Alternatively the material is a conveyor belt. In an eight aspect the invention may broadly be said to consist of a method of forming a material having a wear sensor for monitoring wear of the material comprising the step of embedding in said material a plurality of RFID chips across a thickness of the 10 material and connecting one or more antennae to the RFID chips. In one embodiment the step of embedding in said material a plurality of RFID chips comprises, for each RFID chip, integrating a containment film surrounding the RFID chip with the material. In an alternative embodiment the step of embedding in said material a plurality 15 of RFID chips comprises fixing an outer body encapsulating said plurality of RFID chips in said material. In this specification, where reference has been made to external sources of information, including patent specifications and other documents, this is generally for the purpose of providing a context for discussing the features of the present invention. 20 Unless stated otherwise, reference to such sources of information is not to be construed, in any jurisdiction, as an admission that such sources of information are prior art or form part of the common general knowledge in the art. Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the 25 accompanying drawings. As used herein the term "wear liner" refers to any possible liner that an apparatus, for example a chute or conveyer belt, may have that assists in indicating wear of the chute or conveyer belt. As used herein the term "and/or" means "and" or "or", or both. 30 As used herein "(s)" following a noun means the plural and/or singular forms of the noun. The term "comprising" as used in this specification and claims means "consisting at least in part of". When interpreting statements in this specification and claims which include that term, the features, prefaced by that term in each statement, all need to be 35 present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.

-9 The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS 5 The invention will now be described by way of example only and with reference to the following figures. Figure 1 shows an exploded view of a first embodiment of the sensor of the present invention. Figure 2 shows an exploded view of a second embodiment of the sensor of the 10 present invention. Figure 3 shows an exploded view of a third embodiment of the sensor of the present invention. Figure 4 shows a schematic diagram of a system utilising a sensor of the present invention. 15 Figure 5 shows a perspective view of a fourth embodiment of the sensor of the present invention. Figure 6 shows a cross-sectional view of the sensor of figure 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS RFID technology 20 RFID chip technology is divided into several different types the most common being passive type, non-powered WORM technology (write once read many), such as clothing security tags or SKU identification tags in a warehouse. Although very inexpensive, this technology is effectively "dumb" with no ability to change or vary the RF signature it has been programmed with. 25 RFID chips of the WORM type are programmed (written to) to return a particular code when interrogated by a transceiver (RFID scanner or reader). Thus each RFID chip is a unique identifier. Each RFID chip can be read many times in this manner. Sensor The sensor of the invention uses sacrificial RFID (WORM) chips as a transponder 30 of the sensor. The RFID chips are layered within a sensor body. The sensor body is preferably made up of a medium that will wear at a similar rate to the wear material that it is fixed to, for example, a chute or conveyer belt system. The RFID chips may be layered into specific regions that represent various stages of wear. A sensor in accordance with the present invention is shown in Figure 1. In this 35 example of the sensor of the present invention, multiple layers of RFID microchips (la, 1b, 1c) are encapsulated within a wear medium (not shown) that is contained within an - 10 outer sensor body 4. In the example shown in Figure 1, there are three microchips (la, 1b, 1c). However, any suitable number of microchips may be layered within the sensor depending on the number of wear increments required. It is preferred that the sensor uses high frequency RFID chips. The RFID chip 5 communicates back to a transceiver using induction loop antennae (3a, 3b and 3c). There is preferably one antenna per RFID chip, however, one or more RFID chips may be connected to a single antenna in alternative embodiments and interrogated through the same antenna via distinctive frequencies for example. The sensor body as well as encapsulation medium within the body may be 10 manufactured from various materials. The choice of materials is chosen to accurately reflect the mechanical wear characteristics of the wear material being measured. The shape of the sensor body will also vary based on the thickness, material type, testing environment and profile of the material being measured. For example, a sensor may be used in various locations on a wear plate of a 15 chute or conveyer belt system. The wear plate may be made of a high wear material such as a ceramic or a high wear steel inside a conveyer chute. In the example of Figure 1, the sensor is an elongated tubular member. The advantage of this shape is that it is a versatile shape that can be used inside existing fasteners that hold a majority of existing wear plates inside chutes, for example. Other 20 sensors may be inserted into a wear plate into drilled holes in the wear plate at specific locations. Note must be made that wear plates of conveyer belt systems or product transfer chutes are simply one application of use of the sensor of the present invention. The sensor may be used with other wear plates or wear materials. In an alternative embodiment, the sensor may be embedded/integrated directly 25 into the material for which wear is to be determined, for example during manufacture of the material to be monitored for wear. Referring to figures 5 and 6, a conveyor belt 51 is shown having three RFID chips 54 embedded therein. The conveyor belt may be unidirectional or operational in both directions 55. Any number of one or more RFID chips 54 (but preferably a plurality of chips 54) may be embedded in the conveyor to make up 30 the overall wear sensor. Each RFID chip 54 is contained within a film 53 of material. The film may be formed of any material that is integratable with the conveyor belt material via any suitable method that is known in the art. For example, the film 53 with the RFID chip 54 contained therein, may be moulded or woven into the conveyor belt material during manufacture of the belt. The film may be additional to the conveyor belt material 35 or may form part of the existing conveyor belt material. Other parts of the wear sensor circuit including the antennae and the corresponding connection paths are also directly - 11 integrated into the conveyor belt material. In this manner the wear sensor is directly integrated and entirely housed within the conveyor belt material, such that the conveyor belt forms the sensor body. As shown in figure 6, each RFID chip 54 and corresponding containment film 53 5 is embedded at a particular depth relative to the thickness of the conveyor belt 51 so that the plurality of chips 54 become layered across the thickness of the belt 51. Degradation of the conveyor belt material will lead to successive damage of the layered RFID chips 54. As mentioned above, identification and analysis of wear can therefore be achieved the interrogation of the functional state of each chip 54. Wear of the conveyor 10 belt and damage of the RFID chips may be caused by over stressing any part of the wear sensor circuit or by damaging the circuit through wear caused by abrasion for example. Each RFID chip 54 can be embedded in any desired orientation and any desired position along the belt 51. One or more RFID chips 54 may be embedded within each layer along the length and/or across the width of the belt 51 (at each layer). The RFID 15 chips 54 may or may not be aligned across the thickness of the material 51. The overall wear sensor (made up of the plurality of RFID chips 54) may therefore span partially or fully across the width, and partially or fully along the length of the conveyor belt 51. In some embodiments, the wear sensor may be longer than the circumference of the conveyor or wider than the width of the conveyor. The containment film 53 may be wider 20 and/or longer than the belt 51. Fibres, strands, wires and parts of the conveyor belt material can also form part of the wear sensor circuit. The RFID microchip (la, lb or 1c) and a respective antenna (3a, 3b or 3c) make up a transponder. Each antenna is connected to its respective microchip directly or via longer connection paths, for example, that connection path 2 as shown in Figure 1. 25 Each RFID chip is actuated or interrogated by applying a radio frequency interrogation signal using an RFID scanner/reader as are known in the art. The energy applied to the RFID chip via the antenna enables the chip to communicate/respond pre programmed codes back to the RFID scanner/reader (transceiver). The RFID transceiver is preferably located at a user base or appropriate area, such that a user may be alerted 30 as to the status/wear condition of the sensor and wear condition of the apparatus being monitored. If one microchip (1a, lb or 1c) is damaged or if the antenna (3a, 3b or 3c) or connection path 2 is broken, no signal is returned to the transceiver as no electric current can flow within the microchip.

- 12 In this way the functional status/condition of each of the RFID chips can be dynamically monitored by scanning with the transceiver the RFID chips continuously in order to assess their status. The transceiver may be connected to circuit or similar that includes an alarm to 5 alert the user that a microchip/antenna has been destroyed. Alternatively, the transceiver may supply data to a processor or computer. The computer or processor providing a wear profile based on the data from the transceiver. The alarm or the wear profile giving an indication of the particular sensor and its position in the wear liner and hence that the wear liner or wear medium has been worn away at that position. 10 By layering or positioning various RFID chips into various regions within the medium of a sensor body, various stages of wear can be dynamically monitored as the chips are rendered inactive by breaking any part of its electrical circuit through wear. In the preferred embodiment, the RFID chips are position within the sensor body such that they are distributed/disposed across the thickness of the wear medium/plate in situ. 15 Sensors may be placed at various locations of a wear plate/liner or chute, for example, or simply in a wear material that needs to be monitored, in order to measure wear effectively across a wide surface area. Remote scanners (transceivers) continuously and dynamically scan these sensors and return the identification codes received from all active RFID chips within the various sensors. As the wear regions are 20 impacted through plate wear, RFID sensor circuits within the regions of the wear medium are broken and do not respond when interrogated. Software can determine when RFID sensors have failed thereby calculating the rate of wear as well as wear patterns across a specific area of measurement. The layering of sensors allows for the measurement of the rate of wear. 25 Each subsequent failure of an RFID chip at each layer represents a percentage of wear of a wear plate across its thickness. Each subsequent failure of an RFID chip across various sensors on a wear plate represents a wear pattern across the surface of a plate. RFID chip failure within and across sensors therefore enables the measurement of the percentage of wear across the surface of a wear plate. 30 Figure 4 shows a schematic diagram of a system utilising a sensor of the present invention. A wear plate 106 (forming part of a chute, conveyer system etc) has three sensors 105 embedded in it and distributed across the wear surface of the plate 106. The RFID chips of each sensor 105 are disposed across the thickness of the wear plate 106, starting from at or adjacent the wear surface 106. The sensors are in radio frequency 35 communication (illustrated by the lightning bolts indicated as 104) with a transceiver 103 having an antenna. The transceiver 103 communicates with a reading note 102 that - 13 collects data. For example, the data that may be collected is when the transceiver interrogates each sensor and whether or not there is a response from each sensor. This data is collated at for example a processor or computer 101 giving a determination of wear. A dynamic wear profile may then be provided, for example in the form of a graph, 5 on a graphical display associated with the computer 101. In order to help with the creation of a wear profile of the material being monitored it is preferred that each of the RFID chips and their respective sensor positions within the material being monitored is recorded. This information is loaded onto the processor/computer and used to correlate each failure of an RFID chip. 10 The medium the sensors are contained in is critical as it has to represent the wear material being measured. The medium type and density varies based on the wear characteristics of the material being measured. The sensor is fixed within the wear material in such a way as to most accurately reflect the rate of wear of the wear plate material. The shape of the sensor varies based on the region and environment of 15 application as well as the thickness and profile of the wear plate. The size of the RFID antenna and therefore the size of the sensor body will reflect the scanning distance required. The scanning distance between the reader (transceiver) and the RFID chip (transponder) is a function of the measurement environment. Factors such as obstacles as well as radio interference and shielding will dictate the distance between the remote 20 transceiver and each transponder. Ultra high frequency RFID microchips may be used in the sensor of the present invention. An example of a sensor using ultra high frequency RFID chips is shown in Figure 2. Here, the sensor is comprised of layered microchips (10a, 10b, 10c) that are placed in a "wear region" of the sensor. This wear region is preferably at the uppermost 25 region of the sensor, when placed in the wear liner, for example, and is the area that will be the first to be subjected to wear. Again, the number of chips is determined by the number of wear increments required. In the embodiment of the sensor of Figure 2, three microchips are shown. This is simply an illustration and any required number of microchips may be used. The RFID chip comprising the microchips and respective 30 antennae (12a, 12b, 12c) communicates back to a transceiver (not shown) using radio communication. Again, the RFID chip antenna may be connected directly to the microchip or via a connection path 11. In this instance the antennae (12a, 12b, 12c) are shown stacked on top of each other. As in the previous embodiment the microchips and antennae are encapsulated in 35 a wear medium and surrounded by a sensor body 13.

- 14 An alternative embodiment of the sensor of the present invention is shown in Figure 3. In this embodiment the antennae (22a, 22b, 22c) are placed next to one another and separately encapsulated in a wear medium. Each of the microchips (20a, 20b, 20c) are connected to their respective antennae by a connection path 21. The 5 microchips and connection path are later encapsulated in a body 23. Again, in this embodiment, only three microchips and antennae are shown, but any required number may be utilised. Applications The measurement of wear in various situations across numerous industries 10 maybe achieved using this technology, this invention may be used for the measurement of wear in mining ore conveyor chutes the invention may also be suitable for other high wear areas with the mining operation. RFID chips are layered at predetermined intervals within a particular medium. As each of these chips are sacrificed due to the wear, a wear profile can be determined by the lack of signal from various RFID chips. 15 Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth. Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and/or 20 improvements may be made without departing from the scope or spirit of the invention as defined by the accompanying claims.

Claims (35)

1. A sensor for use to provide an indication of wear, said sensor comprising: at least one RFID chip, 5 at least one antenna connected to said at least one RFID chip, an outer body encapsulating said at least one RFID chip.

2. A sensor as claimed in claim 1 wherein said at least one RFID chip is encapsulated in a wear medium, and wherein the wear medium is encapsulated in said 10 outer body.

3. A sensor as claimed in either one of claim 1 or claim 2 wherein said sensor is adapted to fix to a material in use to provide an indication of wear of the material, and wherein the outer body is of a material that in use will wear at a similar rate to the 15 material that the sensor is adapted to fix to.

4. A sensor as claimed in any one of claim 1 to claim 3 wherein the sensor is an elongate member. 20

5. A sensor as claimed in claim 4 wherein the outer body is an elongate member.

6. A sensor as claimed in claim 5 wherein said at least one RFID chip is disposed at one end of said elongate member. 25

7. A sensor as claimed in claim 6 wherein said at least one antennae are disposed at an opposing end of said elongated tubular member to the respective RFID chips.

8. A sensor as claimed in claim 6 wherein the at least one RFID chip and the at least one antennae are encapsulated by the outer body. 30

9. A sensor as claimed in any one of the preceding claims wherein said at least one RFID chip is a high frequency chip.

10. A sensor as claimed in any one of the preceding claims wherein said at least one 35 RFID chip is an ultra high frequency chip. - 16

11. A sensor as claimed in any one of the preceding claims comprising a plurality of RFID chips and a plurality of antennae, each antenna being connected to an associated RFID chip. 5

12. A sensor as claimed in claim 11 wherein the plurality of RFID chips are layered one upon the other.

13. A sensor as claimed in either claim 11 or claim 12 wherein the plurality of antennae are layered one upon the other. 10

14. A system to determine the wear of a material comprising: at least one wear sensor, including at least one RFID chip and at least one antenna, each wear sensor capable in use of being embedded in a material to which wear of the material is to be monitored. 15

15. A system as claimed in claim 14 wherein the sensor further includes a body encapsulating the at least on RFID chip. 20

16. A system as claimed in either claim 14 or claim 15 further comprising: at least one transceiver capable of sending an interrogation signal to the at least one wear sensor and capable of receiving a response signal from the at least one wear sensor in response to interrogation, and at least one processor communicatively coupled to said transceiver and adapted 25 to initiate transmission of said interrogation signal and determine a condition of wear of each of the at least one wear sensor from the interrogation.

17. A system as claimed in claim 16 wherein the at least one processor is adapted to interrogate a functional state of each of the at least one RFID chip of each of the at least 30 one wear sensor by initiating transmission of one or more interrogation signals to each of the at least one wear sensor, and is further adapted to determine a condition of wear of the wear sensor by determining a functional state of each associated RFID chip based on presence or absence of a response signal from the RFID chip. 35

18. A system as claimed in claim 17 wherein each of the at least one wear sensor comprises a pluarity of RFID chips layered one upon the other and each of the at least - 17 one sensor is embedded across a thickness of the material to dispose the RFID chips across the thickness of the material.

19. A system as claimed in claim 18 wherein the at least one processor is adapted to 5 generate a wear profile across a thickness of the material based on the condition of wear of at least one of the wear sensors.

20. A system as claimed in claim 19 wherein said wear profile includes a representation of a percentage of wear of said material across a thickness of the 10 material.

21. A system as claimed in any one of claim 14 to claim 20 wherein said at least one processor is adapted to generate a wear profile including a representation of a percentage of wear of said material across a surface of the material based on the 15 indication of wear of each of the one or more wear sensors and a relative position of the wear sensor along the surface of the material.

22. A system as claimed in claim 21 wherein said wear profile includes a wear pattern across a surface of said material. 20

23. A system as claimed in any one of claim 14 to claim 22 further comprising a graphical user display connected to the processor to enable display of the wear profile to a user. 25

24. A system as claimed in any one of claim 14 to claim 23 wherein the material to which wear of the material is to be monitored is a wear plate or liner of a conveying medium.

25. A system as claimed in any one of claim 14 to claim 23 wherein the material to which wear of the material is to be monitored is a conveyor belt. 30

26. A method of determining wear of a material comprising the steps of: encapsulating at least one wear sensor in said material, said sensor having at least one RFID chip, and at least one antennae connected to the at least one RFID chip, recording information relating to a relative position of each of the at least one 35 wear sensors in or along said material, - 18 interrogating each of said plurality of RFID chips of at least one wear sensor via a transceiver, determining a wear profile associated with the material based on a response to the interrogation of each of the plurality of RFID chips of the at least one sensor and the 5 relative position of the sensor.

27. A method as claimed in claim 26 wherein each of the at least one wear sensor comprises a pluarity of RFID chips layered one upon the other and each of the at least one sensor is embedded across a thickness of the material to dispose the RFID chips 10 across the thickness of the material.

28. A method as claimed in claim 27 wherein the step of determining a wear profile comprises: determining, for each RFID chip of the at least one sensor, a functional state of 15 the chip, determining a wear condition of the material at each relative position of each sensor along the material, and generating a wear profile associated with wear of said material based on the wear condition at each relative position along the material. 20

29. A method as claimed in any one of claim 26 to claim 28 wherein each wear sensor further includes an outer body encapsulating said at least one RFID chip of the sensor. 25

30. A method as claimed in any one of claim 26 to claim 29 wherein the material is a wear plate or a liner of a conveying medium.

31. A method as claimed in any one of claim 26 to claim 29 wherein the material is a conveyor belt. 30

32. A method of forming a material having a wear sensor for monitoring wear of the material comprising the step of embedding in said material a plurality of RFID chips across a thickness of the material and connecting one or more antennae to the RFID chips. 35 - 19

33. A method as claimed in claim 32 wherein the step of embedding in said material a plurality of RFID chips comprises, for each RFID chip, integrating a containment film surrounding the RFID chip with the material. 5

34. A method as claimed in claim 32 wherein the step of embedding in said material a plurality of RFID chips comprises fixing an outer body encapsulating said plurality of RFID chips in said material.

35. A sensor for use to provide an indication of wear, said sensor comprising: 10 a plurality of RFID chips layered one upon the other, a respective plurality of antennae, each connected to a respective one of said plurality of RFID chips, an outer body encapsulating said plurality of RFID chips and said respective plurality of antennae. 15