Abstract:
A method and system are provided for in-belt conveyor idler condition monitoring. A sensor is mechanically coupled to a conveyor belt and senses a characteristic of a support structure associated with the conveyor belt. The sensor wirelessly transmits a corresponding signal to a monitor system. The monitor system determines a condition of the support structure based upon the transmitted signal. 
     The support structure may be one of a plurality of support structures and characteristics of each of the support structures may be sensed, associated with identifiers for the support structures, and transmitted to the monitor system. The support structure may include a plurality of elements and a characteristic of each element may be sensed and transmitted by one of a corresponding plurality of sensors.

Description:
TECHNICAL FIELD 
   This disclosure relates generally to monitoring systems and more specifically to an apparatus and method for in-belt conveyor idler condition monitoring. 
   BACKGROUND 
   Conveyor belts are used in many applications. In some applications, conveyor belts are used to transport bulk materials such as ore, coal and grain. Conveyor belts in such applications may be as long as 50 kilometers and may be installed in hazardous or environmentally unfriendly areas. 
   Typically, a conveyor belt is driven by a head pulley at one end and a tail pulley at the other end. Between the head pulley and tail pulley, idler rollers are typically used to support the belt. The idlers are typically mounted on a frame and rotate on bearings. 
   SUMMARY 
   This disclosure provides an apparatus and method for in-belt conveyor idler condition monitoring. 
   In a first embodiment, a method includes sensing a characteristic of a support structure of a conveyor belt using a sensor mechanically coupled to the conveyor belt and wirelessly transmitting a signal corresponding to the sensed characteristic. The method also includes determining a condition of the support structure based upon the transmitted signal. 
   In particular embodiments, the support structure is one of a plurality of support structures and characteristics of each of the support structures are sensed and associated with identifiers for the support structures. In other particular embodiments, the support structure includes a plurality of elements and each element is sensed by one of a corresponding plurality of sensors. 
   In a second embodiment, a system includes a conveyor belt, a support structure of the conveyor belt, a sensor mechanically coupled to the conveyor belt, and a monitor system. The sensor senses a characteristic of the support structure and wirelessly transmits a signal corresponding to the sensed characteristic to the monitor system and wirelessly transmits a signal corresponding to the sensed characteristic. The monitor system determines a condition of the support structure based upon the transmitted signal. 
   In a third embodiment, a system includes a sensor, a controller, and a wireless interface. The sensor is mechanically coupled to a conveyor belt, detects a characteristic of a support structure associated with the conveyor belt, and produces a first signal responsive to the characteristic. The controller receives and stores the first signal, and produces a second signal according to the stored first signal. The wireless interface receives and wirelessly transmits the second signal. 
   Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of this disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a schematic diagram of a conveyor belt system in accordance with this disclosure; 
       FIG. 2  is a cross section of a conveyor belt system in accordance with this disclosure; and 
       FIG. 3  is a schematic diagram of an in-belt wireless sensor in accordance with this disclosure. 
   

   DETAILED DESCRIPTION 
     FIG. 1  is a schematic diagram of a conveyor belt system  100  in accordance with this disclosure. A conveyor belt  102  in accordance with this disclosure is installed around a head pulley  106  and a tail pulley  104 . Between the head pulley  106  and the tail pulley  104 , the belt  102  is supported by idler assemblies  108   a - 108   h.    
   Idler wear or bearing failure may result in conveyor belt wear or misalignment. Idler failure may result in a torn conveyor belt, with attendant significant loss of production. In conventional conveyor belt systems, inspection of idlers may be infrequent or expensive for reasons that may include the harshness of the conveyor belt environment, the length of the belt system, the difficulty of inspecting idlers while the belt is in operation. 
   In an embodiment of the present disclosure, wireless sensor systems  110 ,  112  and  114  are embedded in the conveyor belt  102 . As the sensors  110 ,  112  and  114  pass over each of the idler assemblies  108   a - 108   h , the sensors  110 ,  112  and  114  sense one or more characteristics of the idler assembly and store the sensed information for later upload to a monitoring or control system. Uploading of stored information is performed when the sensor  114  comes within wireless communication range of a wireless communication node  116 . Similarly, when the sensor systems  110  and  112  come within communication range of the i-node  116 , they will perform an upload of stored information. 
   The node  116  may also be referred to as an intermediate node, or i-node. The node  116  is in wireless communication with a gateway node  118 , which is in communication over a communication link  122  with a monitor system  120 . 
   While the sensor  114  is shown communicating wirelessly with the i-node  116 , it will be understood that in other embodiments, the sensor  114  may come within wireless communication range of, and communicate directly with, the gateway  118 . Furthermore, where the i-node  116  is not in wireless communication range of the gateway  118 , additional i-nodes may serve to relay wireless communications between the i-node  116  and the gateway  118 . 
   While the conveyor belt  102  is shown with three wireless sensors in  FIG. 1 , it will be understood that in other embodiments, fewer sensors may be used, or additional sensors may be included in a conveyor belt, to provide more frequent upload of stored information relating to idler condition. Similarly, additional i-nodes may be installed at other locations along the conveyor belt system  100  to permit the use of sensors with smaller storage capacity or to provide failure resistant redundant communication, as well as more frequent uploads of stored information. Also, while eight idler rollers are shown in  FIG. 1 , it will be understood that in other embodiments more or fewer idlers may be used. 
   The wireless sensor systems  110 ,  112  and  114  have self-contained power supplies, which may include batteries or other power supply devices. Where the power supply is a battery, the battery may be selected to provide a lifetime of several years, in order to reduce the frequency of stopping the conveyor belt in order to replace the battery. Where the power supply is a rechargeable device, a recharge terminal  124  may be provided to recharge the power supply without requiring contact with the sensors. In the embodiment shown in  FIG. 1 , the recharge terminal  124  utilizes inductive power transfer to recharge the power supply in the sensor system  110 . 
   The recharge terminal  124  also serves as a location reference for the sensors  110 ,  112  and  114  as they pass around the pulleys and idlers of the conveyor belt system  100 . Where the conveyor belt  102  rotates in a clockwise direction, as viewed in  FIG. 1 , the idler assembly  108   g  is identified as the first idler encountered after passing the recharge terminal  124 , followed in sequence by the head pulley  106 , the idler pulley  108   h , the idler assemblies  108   f ,  108   d  and  108   b , the tail pulley  104 , and the idler assemblies  108   a ,  108   c  and  108   e . By using the recharge terminal  124  as a location reference, the sensors  110 ,  112  and  114  are able to identify stored information in a way that may be correctly interpreted by the monitor system  120 . 
   It will be understood that in other embodiments, other location references may be provided for the sensors  110 ,  112  and  114 . In one embodiment, the i-node  116  or other wireless device may provide a location reference. In another embodiment, a unique spacing between idler pulleys may be recognized as a location reference. 
     FIG. 2  is a cross section of a conveyor belt system in accordance with this disclosure. The conveyor belt  102  of  FIG. 1  lies atop an idler assembly  108   a . The conveyor belt  102  is fabricated of rubber and is reinforced with steel cords  222 . Embedded within the belt  102  and flush with, or adjacent to its inner surface (its lower surface in  FIG. 2 ) are the wireless sensor systems  110 ,  112  and  114 . The sensor systems  110 ,  112  and  114  may be encapsulated in rubber as a plug and glued or fastened by other means into position in the conveyor belt  102 . While the sensors are typically spaced along the length of the belt  102 , as shown in  FIG. 1 , they are shown within a single cross section of the belt  102  in  FIG. 2  for ease of description. 
   While the embodiment of  FIG. 2  is a rubber belt with steel cord reinforcements, in other embodiments the conveyor belt may be fabricated from other durable and flexible material, either with or without reinforcements. In still other embodiments, the conveyor belt may be linked segments of metal or other flexible or non-flexible material. 
   The idler assembly  108   a  includes three idler rollers  202 ,  204  and  206  spaced across the width of the conveyor belt  102 , giving the belt  102  a U-shaped configuration when a force  224  that is exerted by material being carried by the belt  102  presses it into the idler rollers. The idler roller  202  rotates about an axle  208  and is supported on the axle  208  by idler bearings  214   a  and  214   b . Similarly, the idler roller  204  rotates about an axle  210  and is supported by idler bearings  216   a  and  216   b . The idler roller  206  rotates about an axle  212  and is supported by idler bearings  218   a  and  218   b . The axles  208 ,  210  and  212  are supported by a base  220 , which may be a solid structure, as shown in  FIG. 2 , or may be a cable running along the periphery of the conveyor belt system  100 . 
   As will be described further with reference to  FIG. 3 , as sensor  110  passes over the idler roller  202 , it senses one or more characteristics of the condition of the roller  202  and the bearings  214   a  and  214   b . Similarly, the sensors  112  and  114  sense characteristics of the rollers  210  and  212 , respectively, and their bearings. 
     FIG. 3  is a schematic diagram of an in-belt wireless sensor system  300  in accordance with this disclosure. The sensor system  300  includes a housing  301  that is adapted for fabrication or mounting within a conveyor belt. The sensor system  300  also includes a controller  308  that is powered by a power supply  314 . Electrically coupled to the controller  308  are a pressure sensor  302 , a vibration sensor  304 , and a temperature sensor  306 . The controller  308  is also electrically coupled to a wireless interface  310 , which sends and receives wireless signals via an antenna  312 . 
   As described with reference to  FIG. 1 , in some embodiments the power supply  314  may be a battery that is replaced when necessary. In other embodiments, the power supply  314  may be a rechargeable device and an optional power input device  316  may be included in the sensor system  300 . The power input device  316  may include a coil, allowing inductive power coupling with a external device such as the recharge station  124  of  FIG. 1 . In still other embodiments, the power input device  316  may be a force transducer (such as a piezo-electric device) that converts some of the force experienced by the sensor when passing over an idler assembly into electrical power in order to recharge the power supply  316 . 
   The wireless sensor system  300  determines that it is passing over an idler from an increase in pressure detected by the pressure sensor  302 . In other embodiments, the system  300  may determine that a sensor is passing over an idler by another method, for example, an amount of time that has passed since the sensor passed a location reference. The controller  308  receives measurements of pressure, vibration and temperature, respectively, from the sensors  302 ,  304  and  306  before, during and after passage of the sensor system  300  over an idler. The controller  308  stores the measurements along with an identifier associated with the idler. As discussed with reference to  FIG. 1 , the identifier may be a sequence number indicating the idler&#39;s position in a sequence of idlers that follow a location reference. 
   When the controller  308  receives a poll message via the antenna  312  and the wireless interface  310  from a wireless transceiver such as the i-node  116  of  FIG. 1 , the controller  308  transmits some or all of the measurements and idler identifiers stored since the last poll message it received. 
   As described with reference to  FIG. 1 , the stored measurements are forwarded from the i-node  116  via the gateway  118  to the monitor system  120 . The application may perform any necessary conversion on the received idler identifier and stores the measurements in a database arranged by idler identifier. The application then analyzes the received information, both within a single measurement and across a time series of measurements to detect characteristics and changes in characteristics of idlers. 
   Characteristics such as the condition of an idler roller surface, misalignment of a roller or bearing causing the idler to be out of true, the condition of idler bearings, and others may be determined from an analysis of various ones of the pressure, vibration and temperature measurements acquired and sent by the wireless sensor systems  110 ,  112  and  114 . Responsive to a condition detected, the monitor system  120  may schedule maintenance on one of idler assemblies  108   a - 108   h , change an operating characteristic of the conveyor belt system  100  or take some other appropriate action. 
   In other embodiments, sensors for characteristics other than pressure, vibration and temperature may be used. In still other embodiments some amount of calculation and analysis may be performed in the wireless sensor system  110 ,  112  or  114  prior to transmitting data to the i-node  116 . In this way, the amount of data to be transmitted may be reduced from an embodiment that transmits raw measurement data from the sensor system. 
   This represents a brief description of one type of wireless sensor system  300  according to the present disclosure. Additional details regarding this type of wireless system are well-known in the art and are not needed for an understanding of this disclosure. Also, this represents one specific type of wireless sensor system  300  that may be used in the conveyor belt system  100 . Other machines or devices could be used that include any other or additional components for wirelessly transmitting sensed information regarding idler assemblies. In addition, this disclosure is not limited to use with conveyor belt systems for transporting ore, coal and grain and could be used with conveyor belt systems that transport other items or materials. 
   The above description and its associated figures have described and illustrated various aspects of one particular implementation of the in-belt conveyor idler condition monitoring wireless sensor  300 . Other embodiments of the wireless sensor system  300  could be used without departing from the scope of this disclosure. 
   In some embodiments, various functions described above are implemented or supported by a computer program that is formed from computer readable program code and that is embodied in a computer readable medium. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of media. 
   It may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer code (including source code, object code, or executable code). The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. The term “controller” means any device, system, or part thereof that controls at least one operation. A controller may be implemented in hardware, firmware, software, or some combination of at least two of the same. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. 
   While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure, as defined by the following claims.