FIELD OF THE INVENTION

This invention relates to fire prevention. In particular the invention relates to a conveyor belt fire prevention system.

BACKGROUND OF THE INVENTION

Conveyor systems are used in numerous industries ranging from mining, food production, paper mills and the like. The conveyor system is heavily relied upon because it provides an easy solution for transporting materials between various processing points. The use of this particular system is not completely without risk as heat build-up from friction and/or bearing failures could result in a conveyor belt fire. It is critical for the fire to be detected as soon as possible to prevent the weakening of the metal structure and potentially its collapse.

The inventor is aware of systems that are capable of detecting conveyor fires. These systems are only useful once a fire has already started and are unable to prevent the fire before it occurs. The response of these systems to the fire is often too late to prevent damage to the equipment and/or injury to the personnel operating the equipment. This invention aims to address this problem. The inventor identified a need for a new system to detect a potential fire hazard before a fire breaks out.

In this specification the term idler is "a pulley that transmits no power but guides or stretches a belt", and can also be termed a roller. Further, the term "shaft" also includes "spindles".

SUMMARY OF THE INVENTION

Broadly according to the invention there is provided a conveyor belt fire prevention system, which includes at least one shaft monitor having a sensor for monitoring the condition of a shaft of at least one conveyor belt pulley in a belt conveyor system and a transmitter in communication with the sensor for transmitting a shaft condition signal; and

at least one associated receiver for receiving the shaft condition signal from the transmitter.

The conveyor belt pulley may be in the form of any one or more of a drive pulley, snub pulley, tail pulley, an idler pulley or the like. The idler pulley may be any one of a carrying/troughing idler pulley or a non-carrying return idler pulley.

The at least one shaft monitor may include a power source for powering the at least one shaft monitor. The power source may be in the form of an electromagnetic inductive coil. In yet a further embodiment the power source may be in the form of a local power source. The local power source may be in the form of a battery. In yet a further embodiment the power source may be in the form of an external power source, such as a mains supply.

The transmitter may be in the form of a wireless transmitter. The transmitter may be in the form of a Radio Frequency (RF) transmitter. The Radio Frequency (RF) transmitter may be selected from any one of: a Wi-Fi transmitter, a long-range transmitter and a short-range transmitter.

In one embodiment the transmitter may be in the form of a short-range transmitter. The short-range transmitter may be in the form of a Bluetooth transmitter or the like. In such embodiment the associated receiver may be in the form of a Bluetooth receiver.

In another embodiment the transmitter may be in the form of a Radio Frequency Identification Tag (RFID Tag). The RFID Tag may be any one of a passive, active and battery-assisted passive Tag. The passive RFID tag may use radio energy transmitted by an RFID reader as a power source. The active tag may include an on-board battery and periodically transmits a signal. The battery-assisted passive tag may have a small battery on board and may be activated when in the presence of an RFID reader. In such embodiment the associated receiver may be in the form of an RFID reader, which sends an interrogation signal to the RFID Tag and reads its response. Alternatively, the RFID tag may periodically send the shaft condition signal to the RFID reader.

In one embodiment the at least one sensor may be in the form of a temperature sensor. The temperature sensor may be in the form of a micro controller based temperature sensor, operable to determine whether the temperature of the shaft rises above a predetermined set temperature. The temperature sensor may be in the form of any one of a thermocouple, thermal switch, semi-conductor device or the like. The predetermined set temperature may be a chosen temperature above a standard operating temperature. The predetermined set temperature may be a chosen temperature which is indicative of a potential fire ignition. In a specific embodiment, the transmitter may include activation means which may be inactive, until the predetermined set temperature is reached, upon which the activation means will activate the transmitter which will then send the shaft condition signal to the associated receiver. In another embodiment the at least one sensor may be in the form of a vibration monitoring sensor. The vibration monitoring sensor may be in the form of an accelerometer. Specifically the accelerometer may be in the form of a piezoelectric accelerometer. The vibration monitoring sensor may be in the form of a micro controller based vibration monitoring sensor, operable to determine whether the vibration of the shaft rises above a predetermined set frequency. The predetermined set frequency may be in the form of a chosen frequency outside a standard operating frequency range. The predetermined set frequency may be a chosen frequency which is indicative of a potential pulley failure which could lead to a fire ignition.

The sensor may be integrated into the shaft. The sensor may be attached to the shaft. The sensor may be embedded in the shaft. Particularly, the sensor may be located towards an end of the shaft. In another embodiment the, sensor may be located in proximity to the shaft, and be in the form of a contact-less sensor. In an embodiment in which the sensor is in the form of a temperature sensor, the contact-less sensor may be in the form of a heat activated device.

The shaft condition signal generated by the transmitter of the at least one shaft monitor, may include any one or both of: notifications that the sensor detected a value above a predetermined value or measurements taken by the sensor. The notification may be a notification that the temperature/vibration of the shaft is too high. The measurement taken by the sensor, in the case of a temperature sensor, may be in the form of the temperature value of the shaft, and in the case of a vibration sensor the measurement may be in the form of the operating frequency value of the shaft.

The shaft condition signal may further include sensor identification information. The transmitter of the shaft monitor may be programmed with the location of the shaft monitor and the sensor identification information may include the location of the sensor/shaft with which it is associated.

The system may further include a remote monitoring station in communication with the at least one associated receiver.

The at least one associated receiver may be in the form of a Radio Frequency (RF) receiver selected from any one of: a Wi-Fi receiver, a Bluetooth (BT) receiver, a RFID reader and another form of RF receiver. The at least one associated receiver may be in the form of a transceiver, receiving the shaft condition signal from the transmitter and transmitting the shaft condition signal to any one of directly to the remote monitoring station or via another transceiver as part of a mesh (relay) transfer system to the remote monitoring station.

The remote monitoring station may be in the form of a remote computer. The remote monitoring station may be in the form of a programmable logic controller (PLC). The remote monitoring station may be wired to the at least one associated transceiver. In another embodiment the transceiver may be operable to wirelessly communicate with the remote monitoring station. The at least one associated transceiver may wirelessly communicate with the remote monitoring station through any one of: Wi-Fi via a local area network (LAN), radio frequency and Bluetooth.

The at least one associated transceiver may include a receiver for receiving the shaft condition signal from the transmitter and a transmitter for transmitting the shaft condition signal to the remote monitoring station.

The transmitter portion of the transceiver may be in the form of a RF transmitter. The RF transmitter may be selected from any one of: a Wi-Fi transmitter, a Bluetooth (BT) transmitter and another form of RF transmitter.

The transceiver may have a receiver-transmitter combination selected from any one of: RFID receiver - Wi-Fi transmitter, RFID receiver - BT transmitter, RFID receiver - other RF transmitter, BT receiver - Wi-Fi transmitter, BT receiver - BT transmitter, BT receiver - other RF transmitter, other RF receiver - Wi-Fi transmitter and other RF receiver - other RF transmitter.

In one embodiment the transceiver may transmit the shaft condition signal to the remote monitoring station via another transceiver. In such an embodiment the transceiver may be part of a mesh system, transmitting the shaft condition signal to another transceiver, which inturn transmits the shaft condition signal to another transceiver, and so forth until the shaft condition signal is transmitted to the remote monitoring station. The remote monitoring station may control a fire deterrent system. In particular, the conveyor belt fire prevention system may include a fire deterrent system controlled by the remote monitoring station. The remote monitoring station may activate and/or deactivate the fire deterrent system based on the shaft condition signal received from the transmitter.

The remote monitoring station may activate the fire deterrent system when it receives a shaft condition signal having a notification from a shaft monitor that the sensor detected a value above a predetermined value, for example that the temperature or vibration of the shaft is too high.

In another embodiment the remote monitoring station may periodically receive measurements taken by the sensor of the shaft monitor, and keeps a trend of the values of the measurements, and activates the fire deterrent system when it receives a measurement value falling outside the trend. For example the remote monitoring station will receive temperature values from the shaft monitor which fall within a specific range of each other, when a shaft condition signal is received in which the temperature is above the trend of the previous temperature values received, the fire deterrent system is activated.

The fire deterrent system may be in the form of any one or more of a conveyor belt stopping mechanism, a water sprayer system, a sprinkler system, a deluge system, an alarm system, an alert system and the like.

The alert system may include sending messages to any one or more of production personnel, engineering personnel, safety personnel, fire department, emergency services and the like.

In a particular embodiment of the invention, the conveyor belt fire prevention system includes

a plurality of shaft monitors as described, each having a sensor for monitoring the condition of a shaft of at least one conveyor belt pulley in a belt conveyor system and a transmitter for transmitting a shaft condition signal; and

at least one associated receiver for receiving the shaft condition signals from the plurality of shaft monitors. The conveyor belt fire prevention system may include a plurality of associated receivers, each receiver associated with a selected group of shaft monitors from which the receiver receives shaft condition signals. The selected group of shaft monitors associated with a particular receiver may be selected based on their proximity to the receiver.

The system may further include a remote monitoring station, as described, in communication with the plurality of receivers. The receivers may be in the form of transceivers, thereby to transfer the shaft condition signals to the remote monitoring station. The remote monitoring station may control a fire deterrent system. The fire deterrent system may be in the form of any one or more of a conveyor belt stopping mechanism, a water sprayer system, a sprinkler system, a deluge system, an alarm system, an alert system and the like.

In use, when a sensor transmits to the associated receiver, that the temperature/vibration of a specific shaft is above the predetermined set temperature/ frequency, the receiver communicates the shaft condition signal, containing the measurement and tag identification information to the remote monitoring station. The remote monitoring station, then activates an alert, and initiates the fire deterrent system in the location of the sensor. In a preferred embodiment, the fire deterrent system stops the associated conveyor belt, initiates water sprayers at the location of the sensor and triggers an alarm. The invention further provides for a method of preventing a fire in a conveyor belt system, which includes

detecting the condition of a plurality of shafts of conveyor belt pulleys in a belt conveyor system;

transmitting shaft conditions of the plurality of pulleys to a remote monitoring station; and

determining whether the shaft conditions are normal or abnormal; and initiating a fire deterrent system, if a shaft condition is abnormal. The invention provides for yet a further method of preventing a fire in a conveyor belt system, which includes

detecting the condition of a plurality of shafts of conveyor belt pulleys in a belt conveyor system and determining whether the shaft conditions are normal or abnormal;

transmitting the shaft condition of a pulley having an abnormal shaft condition to a remote monitoring station; and

initiating a fire deterrent system. Detecting the condition of a plurality of shaft conveyor belts may include at least one shaft monitor, which in use transmits to an associated receiver, that the temperature/vibration of a specific shaft is above the predetermined set temperature/frequency, the receiver communicates the shaft condition signal, containing the measurement and identification information of the shaft monitor to the remote monitoring station.

The step of initiating a fire deterrent system may include the remote monitoring station activating an alert, and initiating the fire deterrent system in the location of the shaft.

The fire deterrent system may stop the associated conveyor belt, initiate water sprayers at the location of the shaft and trigger an alarm.

The invention is now described, by way of non-limiting example, with reference to the accompanying diagrammatic drawings:

FIGURE(S)

In the figure(s):

Figure 1 shows a conveyor belt fire prevention system in accordance with one embodiment of the invention, in which one pulley is monitored.

Figure 2 shows a conveyor belt fire prevention system in accordance with a further embodiment of the invention, in which a plurality of pulleys are monitored. EMBODIMENT OF THE INVENTION

In Figure 1 reference numeral 10 refers to a conveyor belt fire prevention system, which includes a pair of shaft monitors 1 1 each having a sensor 12 for monitoring the condition of a shaft 50.1.1 of a conveyor belt pulley 50.1 in a conveyor belt system and a transmitter 14 in communication with the sensor 12 for transmitting a shaft condition signal. The system further includes an associated receiver 16 for receiving the shaft condition signal from the transmitter 14.

In this example the conveyor belt pulley 50.1 is in the form of an idler pulley. The idler pulley 50.1 includes a stationary shaft 50.1.1 , bearings 50.1.2 and a shell 50.1.3 that revolves around the stationary shaft 50.1.1.

In this embodiment the transmitters 14 are in the form of Radio Frequency Identification Tags (RFID Tag). The RFID Tags 14 are in the form of active tags. Each active tag 14 includes an on-board battery and periodically transmits a signal to the associated receiver 16.

In this example the associated receiver 16 is in the form of an RFID reader which sends an interrogation signal to the RFID Tags 14 and reads their response signals.

The sensors 12 are in the form of temperature sensors. The temperature sensors 12 are in the form of a micro controller based temperature sensors, operable to determine whether the temperature of the shaft 50.1.1 rises above a predetermined set temperature. The predetermined set temperature is in the form of a chosen temperature above a standard operating temperature.

The sensors 12 are integrated into the shaft 50.1.1. Particularly, the sensors 12 are attached to ends of the shaft 50.1.1.

In Figure 2 a conveyor belt fire prevention system 100 is shown which includes a plurality of shaft monitors 1 1.1 , 1 1.2, 1 1.3, 1 1.4, 1 1.5, 1 1.6 each being associated with shafts of specific conveyor belt pulleys 50.1 , 50.2, 50.3, 50.4, 50.5, 50.6 respectively. The shaft monitors 1 1 include sensors (not shown) for monitoring the condition of the shaft of the specific conveyor belt pulley in a belt conveyor system, and transmitters (not shown) in communication with the sensors for transmitting shaft condition signals. The system 100 further includes a plurality of receivers 16.1 , 16.2, 16.3 for receiving the shaft condition signals from transmitters in close range to the receiver.

As shown in Figure 2, the first receiver 16.1 , is in communication with the first two pairs of shaft monitors 1 1.1 , 1 1.2, which are in proximity to the first receiver 16.1. The second receiver 16.2, is in communication with the third and fourth pairs of shaft monitors 1 1.3, 1 1.4, which are in proximity to the second receiver 16.2. The third receiver 16.3, is in communication with the fifth and sixth pairs of shaft monitors 1 1.5, 1 1.6, which are in proximity to the third receiver 16.3.

The system further includes a remote monitoring station 18 in communication with the plurality of receivers 16.1 , 16.2, 16.3. The remote monitoring station is in the form of a programmable logic controller (PLC). In this example, the remote monitoring station 18 is wired to the plurality of receivers 16.1 , 16.2, 16.3, but it is to be appreciated that in another embodiment the receivers may wirelessly communicate with the remote monitoring station 18 via a Local Area Network (LAN). The remote monitoring station controls a fire deterrent system 20. In this example, the fire deterrent system 20 is in the form of a conveyor belt stopping mechanism, a water sprayer system and an alarm system.

Each shaft monitor 1 1 in the system 10 sends tag identification information along with the shaft condition signal. The tag identification information includes the location of the tag.

In use, when a shaft monitor 1 1 transmits to the associated receiver 16, that the temperature of a specific shaft is above the predetermined set temperature, the receiver 16 communicates the shaft condition signal and tag identification information to the remote monitoring station 18. The remote monitoring station 18, then activates an alert, and initiates the fire deterrent system 20 in the location of the sensor 12. In this example, the fire deterrent system 20 stops the associated conveyor belt, initiates water sprayers at the location of the sensor and triggers an alarm.

It is critical for the potential of a fire to be detected. Spillage along a belt conveyor can cause friction between the spillage and idler or pulley shell, which could generate sufficient heat to cause a fire, or damage the conveyor belt. Heat in the shell will be transmitted to the shaft of the idler or pulley, and as the shaft of the idler or pulley is the only stationery part of the idler or pulley under working conditions, it is the ideal medium to measure and transmit heat build up or vibration changes. The detection of heat build up or excessive vibration will also aid with preventing maintenance as failing idlers or pulleys can be changed before any damage to the conveyor system has occurred.

The inventor believes that the invention provides a new fire prevention system for use with conveyor belts. The invention is an improvement over previous systems that are only able to detect when a fire has already ignited. The new fire prevention system has the ability to detect when there is a high risk for a fire breaking out, and initiates a fire deterrent system before any damage has been caused.