Field

This disclosure relates to apparatuses and methods for detecting a failure of a component, such as an idler on a conveyor.

Background

Conveyors, such as conveyor belts, are used to transport a wide range of objects and materials including bulk materials such as ore, packages, products, and people. A conveyor belt includes a conveyor belt looped around spaced apart terminal wheels. At least one of the terminal wheels is powered to cause the conveyor belt to move. An upper portion of the belt is supported by a plurality of idlers located between the terminal wheels. Each idler is free to rotate around its respective axis. Idlers are also known as rollers.

Some conveyors can extend lengths up to kilometres long. Such long conveyor belts are typically used to transport bulk material such as ore and may carry many tonnes of excavated bulk material for extended periods of time. Such long conveyors can have thousands of idlers. Such a high number of idlers raises the probability of an idler of the conveyor failing.

Idler failure can be detrimental for a number of reasons, including:

1 . Conveyor downtime which can delay delivery of bulk material;

2. Damage to the conveyor belt which may be time-consuming and costly to repair;

3. Fire, which is especially dangerous if the bulk material (e.g. coal) is flammable; and

4. A safety hazard to nearby people.

Idler failure is often accompanied by an increase in temperature (i.e. heat) of the idler. For example, if idler ball bearings degrade or are damaged, increased resistance generates heat which causes the idler to heat up. One current practice is to regularly measure the temperature of idlers using a thermographic camera. The camera may identify hot idlers that have, or nearly have, failed. However, a problem with using a thermographic camera includes increased labour needs and can be difficult to simultaneously monitor a number of idlers that may be labour-intensive.

Another practice is to replace idlers before they get towards their expected lifetime to reduce the probability of idler failure. Replacement of the idler may be conveniently performed during a conveyor maintenance period that is scheduled during the life of the conveyor. However, it can be difficult to accurately determine the age of an idler and how much longer it may last.

It is to be understood that, if any prior publication is referred to herein, such reference does not constitute an admission that the publication forms part of the common general knowledge in the art, in Australia, or any other country.

Summary

Disclosed is an apparatus for detecting failure of a component, such as an idler from a conveyor, the apparatus comprising: a temperature sensor in thermal communication with the component; a signal system in electrical communication with the temperature sensor; wherein, when a temperature of the component rises above a threshold temperature as measured by the temperature sensor, the signal system provides a signal to indicate the component has risen above the threshold temperature. The component may fail once its temperature rises above a threshold temperature.

Disclosed is an apparatus to detect a temperature of an idler used in a conveyor, the apparatus comprising: a temperature sensor configured to be mounted to the conveyor so as to be in thermal communication with the idler and to generate a temperature-dependent electrical signal upon heating of the temperature sensor, the temperature sensor generating a trigger electrical signal when a temperature of the idler rises above a threshold temperature; and an indicator system that is configured to receive the electrical signal generated from the temperature sensor and convert the trigger electrical signal into an indicator signal.

Disclosed is an apparatus to detect a temperature of an idler used in a conveyor, the apparatus comprising: a temperature sensor configured to be mounted to the conveyor so as to be in thermal communication with the idler and to generate a temperature-dependent electrical signal when a temperature of the idler rises above a threshold temperature; and an indicator system that is configured to receive the electrical signal generated from the temperature sensor and convert the electrical signal into an indicator signal.

Disclosed is an apparatus that is used to detect a temperature of an idler used in a conveyor, the apparatus comprising: a temperature sensor configured to be mounted to the conveyor so as to be in thermal communication with the idler and to generate a temperaturedependent electrical signal upon heating of the temperature sensor; and an indicator system that is configured to receive the temperature-dependent electrical signal generated from the temperature sensor and convert the temperature-dependent electrical signal into an indicator signal, wherein, in use, the indicator signal is generated when a temperature of the idler rises above a threshold temperature and the temperature-dependent electrical signal is above a threshold value.

The indicator system may comprise a voltage booster that is configured to boost a voltage of the electrical signal generated by the temperature sensor. The electrical signal generated by the temperature sensor, or the voltage generated by the voltage booster, may range from about 0.1 V to about 2.0V. The temperature sensor may be a thermoelectric generator. The apparatus may further comprise a heat sink in thermal communication with an in-use cold side of the thermoelectric generator.

The indicator signal may be a visual signal. The visual signal may be provided by a light source that is powered by the electrical signal generated by the temperature sensor. The apparatus may comprise two or more light sources. The indicator signal may comprise two or more indicator signals that are configured to illuminate individual light sources of the two or more light sources when a temperature of the idler rises above a respective threshold temperature. The light source may be a light-emitting diode (LED). The indicator system may comprise a wireless signal generator. The indicator signal may be a wireless transmission. The wireless transmission may comprise two or more wireless transmission when a temperature of the idler rises above a respective threshold temperature. The indicator system may include a receiver for receiving the wireless transmission.

The threshold temperature may range from about 35 °C to about 120 °C. The threshold temperature may range from about 70 °C to about 100 °C. The indicator system may be configured to be mounted to the conveyor. The indicator system may be powered using a power output of the temperature sensor. The indicator system may be configured to generate a normal operation signal. In use, the normal operation signal may be generated when a temperature of the idler is below the threshold temperature and the electrical signal is below the threshold value.

Disclosed is an idler structure for use in a conveyor fitted with the apparatus as set forth above.

Disclosed is a conveyor comprising the apparatus as set forth above. The apparatus may be fitted to an idler support structure. Disclosed is a system that is used to detect a temperature of an idler used in a conveyor, the system comprising: a plurality of temperature detecting apparatuses located on a conveyor, each temperature detecting apparatus of the plurality of temperature detecting apparatuses being in thermal communication with an idler, wherein each temperature detecting apparatus comprises: a temperature sensor configured to generate a temperature-dependent electrical signal upon heating of the temperature sensor; and an indicator system that is configured to receive the temperature-dependent electrical signal generated from the temperature sensor and convert the temperature-dependent electrical signal into an indicator signal, wherein, in use, the indicator signal is generated when a temperature of the idler rises above a threshold temperature and the temperature-dependent electrical signal is above a threshold value.

The indicator signal may be a visual signal. The visual signal may be provided by a light source that is powered by the electrical signal generated by the temperature sensor. The system may comprise two or more light sources. The indicator signal may comprise two or more indicator signals that are configured to illuminate individual light sources of the two or more light sources when a temperature of the idler rises above a respective threshold temperature. The light source may be a light-emitting diode (LED). The indicator system may comprise a wireless signal generator, and wherein the indicator signal is a wireless transmission. The wireless transmission may comprise two or more wireless transmissions when a temperature of the idler rises above a respective threshold temperature for each of the two or more wireless transmissions. A property of the wireless signal, or each of the two or more wireless signals, may change once temperature-dependent electrical signal is above the threshold temperature.

The indicator system may include a receiver for receiving the wireless transmission from a second indicator system. The second indicator system may be from a second temperature detecting apparatus of the plurality of temperature detecting apparatuses. Each temperature detecting apparatus of the plurality of temperature detecting apparatuses may be located on an idler support structure. The indicator system may comprise a voltage booster that is configured to boost a voltage of the electrical signal generated by the temperature sensor. The temperature sensor may be a thermoelectric generator. The system may further comprise a heat sink in thermal communication with an in-use cold side of the thermoelectric generator. The threshold temperature may range from about 35 °C to about 120 °C. The threshold temperature may range from about 70 °C to about 100 °C. The indicator system may be configured to generate a normal operation signal. In use, the normal operation signal may be generated when a temperature of the idler is below the threshold temperature and the electrical signal is below the threshold value. The indicator system may be powered using a power output of the temperature sensor.

Disclosed is a method of detecting a temperature of an idler used in a conveyor, the method comprising: operating a conveyor to cause the idler to rotate and generate heat to thereby increase a temperature of the idler; measuring a temperature of the idler with a temperature sensor that is mounted to the conveyor, the temperature sensor generating a temperaturedependent electrical signal upon heating; and converting the temperature-dependent electrical signal to an indicator signal when the idler is above a threshold temperature of the idler.

The method may further comprise boosting a voltage of the electrical signal prior to converting the electrical signal to the indicator signal. The temperature sensor may be a thermoelectric generator. A method may further comprise dissipating heat from a cold side of the thermoelectric generator using a temperature regulator.

The indicator signal may be a visual signal. The visual signal may be a light source that is powered by the electrical signal generated by the temperature sensor. The method may further comprise generating a plurality of visual signals, wherein each visual signal is powered by a respective electrical signal. The threshold temperature may comprise a plurality of threshold temperatures so that the temperature sensor generates a plurality of electrical signals for each respective threshold temperature. Each electrical signal of the plurality of electrical signals may illuminate one light source of a plurality of light sources. The light source may be a light-emitting diode (LED).

The indicator signal may be a wireless transmission. The wireless transmission may comprise two or more wireless transmissions when a temperature of the idler rises above a respective threshold temperature for each of the two or more wireless transmissions. A property of the wireless signal, or each of the two or more wireless signals, may change once temperature-dependent electrical signal is above the threshold temperature. The wireless signal may be a first wireless signal. The method may further comprise receiving a second wireless transmission. Information from the second wireless transmission may be passed with the first wireless transmission. The threshold temperature may range from about 35 °C to about 120 °C. The threshold temperature may range from about 70 °C to about 100 °C.

Operating the conveyor to cause the idler to rotate and generate heat to thereby increase a temperature of the idler may cause the temperature sensor to generate a power output that is used by the indicator system to generate the indicator signal. The method may further generate a normal operation signal when a temperature of the idler is below the threshold temperature and the electrical signal is below the threshold value.

Brief Description of Figures

Embodiments will now be described by way of example only with reference to the accompanying non-limiting Figures, in which:

Figure 1 shows a schematic representation of an embodiment of an apparatus.

Figure 2a shows an embodiment of an apparatus.

Figure 2b shows another embodiment of an apparatus.

Figure 3 shows an embodiment of a circuit diagram associated with the apparatus shown in Figure 2a or Figure 2b.

Figure 4 shows another embodiment of an apparatus.

Figure 5 shows an embodiment of a conveyor system.

Figure 6 shows another embodiment of a conveyor system.

Figure 7 shows an embodiment of a process flow diagram for an apparatus. Figure 8 shows an embodiment of a process flow diagram for an apparatus. Figure 9 shows an embodiment of a process flow diagram for an apparatus.

Detailed Description

Disclosed is an apparatus to detect a temperature of an idler used in a conveyor. As shown schematically in Figure 1 , apparatus 10 has a temperature sensor 12. The temperature sensor 12 is configured to be mounted to a conveyor, such as a stationary component of the idler including an idler frame, idler support, or idler shaft. The location where the temperature sensor is to be mounted is in thermal communication with the idler. The temperature sensor 12 in use generates a temperature-dependent electrical signal. The terms “temperaturedependent electrical signal” and “electrical signal” are used interchangeably throughout this disclosure.

The temperature sensor 12 is in electrical communication with an indicator system 16. The electrical signal generated by the temperature sensor 12 is received by the indicator system 16. The indicator system 16 generates an indicator signal once one or more pre-determined conditions are met.

In an embodiment, a voltage booster 14 is positioned between the temperature sensor 12 and the indicator system 16. The voltage booster 14 is configured to boost a voltage of the electrical signal produced by the temperature sensor 12.

The term “temperature sensor” as used herein includes devices and systems that can measure a temperature and generate an electrical signal. In an embodiment, the temperature sensor 12 has an associated temperature regulator 18. The temperature regulator 18 helps to prevent a temperature of the temperature sensor from exceeding an operational limit and/or helps to improve the performance of the temperature sensor 12. The temperature regulator 18 can include passive heat regulators such as a heat sink or a heat spreader, or active heat regulators such as a heat exchanger.

When a temperature of the idler rises above a threshold temperature, the increase in temperature, as measured by the temperature sensor 12, causes the temperature sensor 12 to generate an electrical signal that is above a threshold value. This electrical signal above the threshold value is a predetermined condition which causes the indicator system 16 to generate an indicator signal.

The threshold temperature may range from about 50 °C to about 120 °C. This means that when a temperature of the idler ranges from about 50 °C to about 120 °C, this temperature, as measured by the temperature sensor 12, causes the generation of the electrical signal that is above a threshold value (i.e. a predetermined condition) to cause the indicator system 16 to generate an indicator signal. In an embodiment, the threshold temperature ranges from about 70 °C to about 100 °C.

It should be noted that the temperature sensor 12 may be mounted near an idler, such as on a frame component of the idler, and that there may be a difference in the temperature of the idler and the e.g. frame component. This offset in temperature can be calculated when determining the temperature required to generate the electrical signal above the threshold value. For example, if the frame component reaches 70 °C when an associated idler reaches 90 °C, a temperature offset of 20 TD is used when calculating and generating the electrical signal above the threshold value. The temperature offset value is determined by e.g. the location of the temperature sensor 12 relative to the idler, the thermal conductivity of the components between the temperature sensors 12 and the idler, and the environmental conditions. In an embodiment, the temperature sensor 12 is located on or proximate a shaft of the idler.

The indicator system 16 can generate an indicator signal in several ways such as illumination of a light, generating an audio signal, communicating with a safety system, and so on. For conveyors that are used in harsh and/or hazardous environments, such as on a mine site, it may be advantageous to use non-hazardous components that do not require an external power source. For example, when the indicator signal is a light, the light may be powered only by the electrical signal generated by the temperature sensor 12. Not needing an external power source to power the apparatus 10 can help to reduce operational complexity, increase safety, simplify installation of the apparatus 10, and improve reliability.

In an embodiment, the indicator system 16 generates an indicator signal irrespective of how the electrical signal above the threshold value is generated. For example, if a temperature of the idler quickly reaches the threshold temperature over (e.g. an hour) or slowly reaches the threshold temperature (e.g. over a few months of continuous use), once the threshold temperature is reached the indicator system 16 generates the indicator signal.

Another embodiment of an apparatus to detect a temperature of an idler used in a conveyor is shown in Figure 2a. Apparatus 100 has a temperature sensor in the form of a thermoelectric generator 120. The thermoelectric generator 120 works on the same principle as a thermocouple using the Seebeck effect to generate a voltage based on a temperature of an object. The voltage generated by the thermoelectric generator 120 is the electrical signal. Accordingly, in an embodiment, the temperature sensor generates a temperaturedependent electrical signal using the Seebeck effect.

A thermoelectric generator will generate a voltage upon application of heat. In an embodiment, the thermoelectric generator 120 powers the indicator system. Generally, a voltage generated by a thermoelectric generator will increase with an increase in temperature difference between the in-use hot and cold sides. The voltage generated by a thermoelectric generator will reach a maximum based upon a maximum temperature difference between the in-use hot and cold sides. The maximum temperature difference is determined by the type and design of thermoelectric generator.

Attached to an in-use cold side of the thermoelectric generator 120 is a temperature regulator in the form of a heat sink 122. The heat sink 122 helps to dissipate heat from the thermoelectric generator 120. The heat sink 122 is an aluminium heat sink, though heat sinks of other types of materials could be used. A passive heat sink may advantageously help to reduce the number of components of the apparatus 100. The heat sink 122 helps to maintain a temperature difference between the in-use hot and cold sides of the thermoelectric generator 120. Maintaining a temperature difference between the in-use hot and cold sides of the thermoelectric generator 120 helps to improve the reliability and efficiency of the apparatus 100. In an embodiment, a face of the heat sink 122 that contacts the thermoelectric generator 120 is larger than a surface area of the in-use cold side of the thermoelectric generator 120.

The heat sink 122 is not required in all embodiments. For example, in cold environments the ambient temperature of the atmosphere surrounding the in-use cold side of the thermoelectric generator 120 may be sufficient to maintain an adequate temperature different between the in-use hot and cold sides to generate a voltage without the need for the heat sink 122. Thermal paste may be used to increase thermal conductivity between the in-use cold side of the thermoelectric generator 120 and the heat sink 122.

In the embodiment shown in Figure 2a, the thermoelectric generator 120 is electrically connected to voltage booster 124 via wires 129a and 129b. The voltage booster 124 boosts a voltage of the electrical signal generated by the thermoelectric generator 120. Generally, a thermoelectric generator will produce a voltage in the order of about 0.4 V. In the embodiment shown in Figure 2a, the voltage booster 124 boosts the voltage from about 0.4 V to about 2.7 V. The amount the voltage is boosted is dependent upon the electrical requirements of the indicator system and the voltage output from the thermoelectric generator 120. Types of voltage boosters that can be used as the voltage booster 124 include a joules thief circuit, etc. that can be made using e.g. ICS and TRANSISTORS, such as a bipolar junction transistor. A circuit diagram of an embodiment of the apparatus 100 including a voltage booster is shown in Figure 3.

In an embodiment, and as best seen in Figure 2b, the voltage booster 124 and integrated circuit 128 are formed from a single circuit segment 125. The single circuit segment 125 forms the indicator system 16. The single circuit segment 125 is mounted onto the heat sink 122. Thus, apparatus 100a provides a single installable unit rather than having to separately install the thermoelectric generator 120 and indicator system 16.

The voltage booster 124 is needed when an output voltage of the thermoelectric generator 120 is insufficient to generate the temperature-dependent electrical signal that is above a threshold value. The voltage booster 124 may be used to increase an output of the thermoelectric generator 120 to provide sufficient power to power the indicator system 16. Alternatively, if the thermoelectric generator 120 can produce a voltage that is above the threshold value, the voltage booster 124 is not required. Therefore, the voltage booster 124 is not required in all embodiments.

The apparatus 100 has an indicator system in the form of a light-emitting diode (LED) lights 126. In an embodiment, the LED lights 126 form part of an integrated circuit 128. The apparatus 100 is shown as having three LED lights, but any number of LED lights can be used as the indicator system. In the embodiment shown in Figure 2a, the integrated circuit 128 and the voltage booster 124 are integrated. However, the integrated circuit 128 is not always integrated into the voltage booster 124 but may instead be electrically connected. Illumination of the LED lights 126 provides a visual signal.

In Figure 2a the apparatus 100 is mounted to a structure 130. The structure 130 can be an idler structure such as an idler frame or idler shaft. As a temperature of the structure 130 raises, a temperature-dependent electrical signal (i.e. voltage) generated by the thermoelectric generator 120 increases. The voltage of the temperature-dependent electrical signal is boosted by the voltage booster 124. When a temperature of the structure 130 rises past a threshold temperature, the boosted voltage rises past a threshold value, and the LED lights 126 begin to illuminate. In this instance, the threshold value is the threshold potential of the LED to allow for illumination of the LED. When a temperature of the structure 130 is below a threshold temperature the electrical signal (i.e. voltage) is below the threshold value which means the LED is “off”. Increasing the temperature of the structure past the threshold temperature causes the electrical signal (i.e. voltage) to increase past the threshold value which means the LED is turned “on”.

In an embodiment, the power generated by the thermoelectric generator 120 may be used by the indicator system to provide a normal operation signal. The normal operation signal may be used to indicate that the apparatus is operating below the threshold temperature. In apparatus 100, the normal operation signal can be provided by one or more of the LED lights 126a, 126b and 126c providing a visual signal that is different from a visual signal generated when a temperature of the structure 130 is above the threshold temperature. For example, the visual signal for the normal operation signal may be a blue light. In an example, the visual signal for the normal operation signal may be a green light. In an embodiment, a colour of the LED light 126-126c that signals the normal operation signal is different to a colour used to signal that a temperature of the structure 130 is above the threshold temperature. The normal operation signal may be generated once the thermoelectric generator 120 has a power output above a minimum threshold. In this way, in an embodiment the thermoelectric generator 120 powers the indicator system (e.g. LED lights 126). In an embodiment, the apparatus 100 is powered by the output of the thermoelectric generator 120.

In an embodiment the thermoelectric generator 120 is positioned on an idler support structure either in close proximity to or in contact with an axle of the idler. For example, an in-use hot side of the thermoelectric generator 120 may in thermal contact with an end face of the axle. Conductive paste may be used to help improve thermal conductivity between the in-use hot side of the thermoelectric generator 120 and the structure. Heat generated by the idler is conducted through the axle and into the support structure. Placing the thermoelectric generator 120 close to the idler may help to provide accurate temperature measurements of the idler. Generally, there may be some heat loss during the conduction of heat from the idler, through the shaft and to the support structure. The threshold values for the electrical signal can be selected to incorporate any offset temperature between an idler temperature and structure temperature.

The apparatus 100 is shown as having three LED lights 126a, 126b and 126c. The LED lights 126a-126c can be illuminated simultaneously or sequentially. In an embodiment, the apparatus 100 has a plurality of LED lights that may each be illuminated at separate threshold values. For example, the apparatus 100 could have three LED lights, with each LED light being illuminated (turned on) at respective first, second and third threshold values. In an embodiment, each of the first, second and third threshold values differ and correspond with different temperatures of the structure 130. For example, the first threshold may be an electrical signal generated by the thermoelectric generator 120 when the structure 130 is at 70 °C, the second threshold value may be an electrical signal generated by the thermoelectric generator 120 when the structure 130 is at 90 °C, and the third threshold value may be an electrical signal generated by the thermoelectric generator 120 when the structure 130 is at or above 100 °C. In this example, the specific electrical signal (e.g. voltage) when the structure 130 is at 70 °C, 90 °C and 100 °C depends on the type of thermoelectric generator 120, voltage booster 124, and LED light 126.

It should be noted that the output voltage of a thermoelectric generator is proportional to a difference in temperature of the in-use hot and cold sides and it stabilizes after reaching a maximum voltage based on a maximum temperature difference. Once this voltage is reached, it does not increase even if a temperature of the hot side increases (i.e. a temperature difference increases). This is because a temperature difference between the in- use hot and cold sides is saturated by multiple factors including thermal conductivity of temperature sensor/thermoelectric generator, and heat dissipation capability of the in-use cold side, such as though a heat sink.

Having a plurality of LED lights being turned on with different threshold values can enable multiple signalling from the indicator system. For example, when three LED lights are used, a first LED can be illuminated at a “pre-warning” stage to indicate that the idler is approaching a temperature where the idler is beginning to fail, a second LED can be illuminated at a “failure” stage where the idler is at a temperature where the idler is known to fail, and a third LED can be illuminated at an “emergency” stage where the idler is at a temperature where the idler has failed and should be replaced immediately to prevent any damage to the conveyor. These different stages are exemplary and serve only to describe how the indicator system could be set up.

In an embodiment, the threshold values are determined by the indicator signal. In an embodiment, the threshold values used to determine when a LED is illuminated is determined by the “on” threshold value of the LED. For example, a first LED may have an “on” threshold of 1.0 V which equates to a first threshold temperature, a second LED may have an “on” threshold of 1.25 V which equates to a second threshold temperature, and a third LED may have an “on” threshold of 1.5 V which equates to a third threshold temperature. As a temperature of the structure 130 increases, the electrical signal generated by the thermoelectric generator 120 increases (and, if fitted, boosted by the voltage booster), and once the voltage is above 1 .0 V the first LED is illuminated. As the temperature rises, the voltage rises and once above 1 .25 V the second LED is illuminate, and a further increase in temperature causes the electrical signal to rise above 1 .5 V to cause the third LED to be illuminated. An example of an indicator system using three LED lights to indicate different temperatures and how these temperatures correlate to different threshold voltages is shown in Table 1 . Note that the conditions disclosed in Table 1 are exemplary only and the specific threshold temperatures and threshold voltages used may vary and will depend upon the specific application.

Table 1 . The apparatus 100 has been described with a visual or light-based indicator system. However, the disclosure is not limited to a visual or light-based indicator system. For example, and as best shown in Figure 4, the indicator system can include wireless transmission. Apparatus 300 is similar to apparatus 100a, but the integrated circuit 128 with the LED lights 126 in apparatus 100 has been replaced with integrated circuit 310 to provide a single installable unit rather than having to separately install the thermoelectric generator 120 and indicator system 16. Apparatus 300 is shown in Figure 4 as being mounted to structure 130. Integrated circuit 310 is shown as being connected to, or integrated with, voltage booster 124. The voltage booster 124 is not require in all embodiments of the apparatus 300.

The integrated circuit 310 has a wireless signal generator in the form of wireless signal transmitter 312. The transmitter 312 can emit RF, IF, Wi-Fi, and/or Bluetooth signals. When temperature of the structure 130 rises above a threshold temperature, the thermoelectric generator 120 generates an electrical signal that is above a threshold value. This electrical signal triggers the wireless signal transmitter to transmit a wireless signal or wireless transmission. This wireless signal can then be received by another device to indicate that the structure 130 is above the threshold temperature. In an embodiment, two or more wireless transmissions are generated when a temperature of the structure 130 rises above respective threshold temperatures. For example, a first wireless signal with a first condition or property may be generated when the structure 130 is above a first threshold temperature, and a second wireless signal with a second condition or property may be generated when the structure 130 is above a second threshold temperature. The different threshold temperatures may be that outlined in Table 1 .

In an embodiment, the power generated by the thermoelectric generator 120 may be used by the indicator system to provide a normal operation signal. The normal operation signal may be used to indicate that the apparatus is operating below the threshold temperature. In apparatus 300, the normal operation signal can be provided by the transmitter 312 emitting a ‘normal operation’ wireless signal. The normal operation wireless signal is different to the wireless signal generated when temperature of the structure 130 rises above a threshold temperature. In an embodiment, a property of the normal operation wireless signal is different to the wireless signal generated when temperature of the structure 130 rises above a threshold temperature. For example, one or more of frequency, signal type (e.g. Wi-Fi, Bluetooth, IF, RF), or signal information. The normal operation signal may be generated once the thermoelectric generator 120 has a power output above a minimum threshold. In this way, in an embodiment, the thermoelectric generator 120 powers the indicator system (e.g. transmitter 312). In an embodiment, the apparatus 300 is powered by the output of the thermoelectric generator 120.

Depending on the location of the apparatus 300, the wireless signal may need to be boosted or retransmitted to a desired location, such as a motor room. Accordingly, in an embodiment, the apparatus 300 includes a receiver 314 for receiving a wireless signal or wireless transmission. For example, a wireless signal from an adjacent apparatus 300 could be received by receiver 314, then retransmitted through transmitter 312. The receiver 314 can receive a wireless signal from an adjacent or proximal apparatus. For example, the receiver 314 may receive a wireless signal from any apparatus 300 within a predefined distance. The predefined distance may be 0.1 m -5 m. The range may be 0.5 m to 4 m. The range may be 0.5 m to 3 m. The range may be 0.5 m to 2 m. The range may be 0.5 m to 1 m. The range may be 0.1 m to 2 m. The range may be 0.1 m to 1 m.

A plurality of apparatus 300 can be used to form a conveyor system. Each apparatus 300 can be considered as forming a temperature detecting apparatus. As best seen in Figure 5 and Figure 6, a conveyor system 700 has a plurality of idlers 712a-712f, each being mounted on respective idler support frames 710a-710f. The idlers 712 supports a conveyor belt 714. An apparatus 300a-300f is mounted on or fixed to a respective idler support frame 710a-710f. When one of the apparatuses 300a-300f generates an electrical signal, the associated wireless transmission can be received then further transmitted in a linear or daisy-chain manner. For example, if apparatus 300a detects that idler support frame 710a, and thus idler 712a, is above the threshold temperature, it will generate a wireless signal 716 from transmitter 312. Wireless signal 716 is received by adjacent apparatus 300b, where the wireless signal is then transmitted and passed along each adjacent apparatus 300b-300f until the wireless signal reaches motor room 718. The wireless signal can then be processed in the motor room 718 to indicate that apparatus 300a has triggered and that idler 712a requires inspection. The daisy-chaining of the wireless signal 716 means each apparatus can act as a buffer or node point to allow the wireless signal 716 to be received by the motor room.

In an embodiment, and as best seen in Figure 6, the wireless signal 716 can skip a number of adjacent apparatus and instead transmit to a proximal apparatus. For example, in Figure 6, wireless signal 716 passes from apparatus 300a to apparatus 300c, and then to apparatus 300e and finally onto apparatus 300f before being transmitted to the motor room 718. The number of apparatus 300 that the signal jumps or skips is dependent on the spacing between each apparatus 300, and the strength of the wireless signal 716.

In an embodiment, each apparatus 300 is provided with an apparatus binary code that is transmitted with the wireless signal 716. Accordingly, when the wireless signal is received in the motor room 718, details of specific apparatus 300 can be identified.

The type of wireless signal or wireless signal properties may change depending on threshold values. For example, Table 2 shows exemplary values for temperatures and voltages to generate different wireless signal conditions to signify different temperatures of e.g. structure 130. The integrated circuit 310 may have an AND gate that controls transmission of a wireless signal from transmitter 312.

Table 2.

A process flow diagram for apparatus 300 for transmitting a wireless signal is shown in Figure 7. In process flow 400, the apparatus 300 detects at step 412 whether the temperature-dependent signal is above the threshold value. If the temperature-dependent signal is below the threshold value, the process flow goes back to the start 410. However, if the temperature-dependent signal is above the threshold value, a wireless signal is sent at step 414 from transmitter 312.

A process flow diagram for apparatus 300 for receiving a wireless signal from an adjacent or proximal apparatus 300 is shown in Figure 8. In process flow 500, the apparatus 300 detects at step 512 whether a wireless signal has been received from the adjacent or proximal apparatus 300. If a wireless signal has not been received, the process flow goes back to the start 510. However, if a wireless signal has been received, the wireless signal is transmitted as an auxiliary wireless signal at step 514. In an embodiment, apparatus 300 can both generate its own wireless signal if the temperature-dependent signal is above the threshold value, and also transmit an auxiliary wireless signal from an adjacent or proximal apparatus 300. In this way, process flows 400 and 500 are performed simultaneously or sequentially. For example, in process flow 600 shown in Figure 9, the apparatus 300 detects at step 612 whether the temperaturedependent signal is above the threshold value. If the temperature-dependent signal is below the threshold value, the process flow goes back to the start 610. However, if the temperature-dependent signal is above the threshold value, a wireless signal is sent at step 614 from transmitter 312. Then at step 616 it is determined if a wireless signal has been received from the adjacent or proximal apparatus 300. If a wireless signal has not been received, the process flow goes back to the start 610. However, if a wireless signal has been received, the wireless signal is transmitted as an auxiliary wireless signal at step 618. Steps 612, 614 and 616 relate to, respectively, steps 410, 412 and 414 from process flow 400, and steps 616 and 618 relate to, respectively, steps 512 and 514 from process flow 500.

When the apparatus 10/100/100a/300 is fitted to a structure associated with an idler, such as an idler structure, idler frame, idler bracket or idler shaft, a temperature of the structure tends to rise slowly over a period of time in use of the conveyor. Accordingly, it may be advantageous if the indicator system, e.g. indicator system 16, generates the indicator signal once a temperature of the structure raises above the threshold temperature irrespective of how long it took to reach the threshold temperature.

An advantage of apparatus 100, apparatus 100a and apparatus 300 may be that they use passive components that do not require power or control from external systems. This makes apparatus 100, apparatus 100a and apparatus 300 self-contained which may help to reduce operational and installation costs of the apparatus 100, apparatus 100a and apparatus 300 but may also help to make the apparatus 100, apparatus 100a and apparatus 300 non- hazardous. Non-hazardous devices are typically required on mine sites to minimise operational risk and health and safety concerns. By providing a visual signal in the form of a LED light 126 that can be illuminated, the apparatus 100 may provide a simple way for an inspector to quickly identify idlers which may need maintenance or replacement. For example, a colour of the light or a certain number of illuminated lights could be used to indicate that an idler is operating above a threshold temperature and that it should be scheduled for maintenance or replacement.

An advantage of apparatus 300 may be that it eliminates, or at least reduces, the need for manual inspection since the details of a specific apparatus can be identified based on a binary code of the apparatus 300. This may be useful for long (e.g. >1 km) conveyors. An advantage of system 700 may be that the conveyor can be extended or shortened without the need to modify each apparatus 300. For example, if additional idlers 712 or idler support frames 710 are added to system 700, there is no need to modify existing apparatuses 300, nor any need to provide extra services such as power to the additional apparatuses. This modular approach may make system 700 highly adaptable.

As each of apparatus 100, 100a and 300 can be powered by and respond to heat generated by an idler, each apparatus 100, 100a and 300 can be considered as being or forming part of a reactive monitoring system.

The above detailed description has been made with reference to an idler used on a conveyor, but it should be appreciated that the disclosed apparatus and method can be used to monitor a temperature of a wide variety of structures.

In the claims which follow and in the preceding description of the disclosure, except where context requires otherwise due to expressed language or necessary implications, the word “comprise” or variants such as “comprises” or “comprising” is used in an inclusive sense i.e. to specify the presence of the state features but not to preclude the presence or addition of further features in various embodiments.