Patent Description:
Conveyor belts can be subjected to harsh conditions. As a result, the belts can degrade and/or fail due to tears and the like.

What is needed are techniques to scan and/or monitor conveyor belts and identify or detect belt degradation prior to belt failure. Furthermore, techniques are needed that monitor conveyor belts safely.

<CIT> discloses an inspection method for conveyor belts using terahertz radiation. A measurement setup with one transmitter and up to two receivers is used, which makes it possible to detect and evaluate both the radiation transmitted by the conveyor belt and the radiation reflected by the conveyor belt. The total thickness of the steel cord conveyor belt is calculated by the time difference between two reflected terahertz waves.

The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the disclosure, its application, or uses. The description is presented herein solely for the purpose of illustrating the various embodiments of the disclosure and should not be construed as a limitation to the scope and applicability of the disclosure. In the summary of the disclosure and this detailed description, each numerical value should be read once as modified by the term "about" (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary of the disclosure and this detailed description, it should be understood that a value range listed or described as being useful, suitable, or the like, is intended that any and every value within the range, including the end points, is to be considered as having been stated. For example, "a range of from <NUM> to <NUM>" is to be read as indicating each and every possible number along the continuum between about <NUM> and about <NUM>. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific data points, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors had possession of the entire range and all points within the range.

In addition, use of the "a" or "an" are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of concepts according to the disclosure. This description should be read to include one or at least one, and the singular also includes the plural unless otherwise stated.

The terminology and phraseology used herein is for descriptive purposes and should not be construed as limiting in scope. Language such as "including", "comprising", "having", "containing", or "involving", and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited.

Also, as used herein, any references to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily referring to the same embodiment.

It is appreciated that conveyor belt monitoring using various sensor technologies is possible. However, there are a range of potential safety, reliability, dimensional, cost and the like issues that can prevent or mitigate the use of sensor-based belt monitoring.

Embodiments according to the disclosure include condition monitoring of fabric- or textile-reinforced or containing rubber products, PVC, polymer coated constructions and the like, which are used in harsh applications and are subject to damage events. If these damage events are critical in nature or become progressively worse, the rubber product could suffer from a catastrophic event, by either developing a longitudinal rip or a transverse tear. This may lead to shut down operations or even lead to lengthy downtime issues as the damaged rubber product is repaired or replaced, and/or the system cleaned and repaired in order to resume operation. Furthermore, if damages in fabric- or textile-reinforced rubber products become severe, then the integrity of the load-carrying medium can be compromised and ultimately leads to complete failure if timely maintenance is not scheduled. These damages could either be in the rubber itself, or if severe enough, also in the fabric- or textile-reinforcement as well.

Additionally, it is appreciated that conveyor belt damage and/or degradation is important to mining conveyor belt systems. The embodiments can provide the ability to detect and react to sources of belt degradation, and the embodiments can extend the life of the belt and enhance operation of mining conveyor belt systems. Further, knowledge of the conveyor belt condition or degradation permits mines or mining operations to plan/schedule belt replacements at selected times that facilitate productivity and efficiency of the mining process. For example, known degradation can permit a system to schedule replacement during low volume or downtimes of a conveyor belt system. Further, the embodiments can provide determination of belt structure and defect characterization using reflective time-of-flight measurements. The embodiments can, for example, determine cover gauges, detect carcass delamination, identify damage events caused by impact or conveyor accessory (such as scraper, wiper, or skirtboard) or structural interactions (such as side travel of belt into structure or scraping on transverse structural elements).

In some aspects, scanning or monitoring conveyor belts to detect, monitor and alarm when hazardous conditions arise can prevent the catastrophic events described above. According to the disclosure, a sensor system detects, assesses and/or monitors changes to damage events and their risk to the integrity of the conveyor belt via either periodic scans or permanently-mounted conveyor scans. Also, by expanding the system to monitor for splice integrity and longitudinal rips in the permanently-mounted systems, the sensor system could further limit damage to the conveyor belt and system by detecting changes in the splice that could lead to a splice failure, prior to the failure, allowing for preventative actions to be taken, and by limiting longitudinal rips in the system due to damage to dielectric elements that are embedded at regular intervals over the length of the conveyor belt. In one example, a tear is in a transverse direction and a rip is in a longitudinal direction.

It is appreciated that one type of scanning or imaging uses terahertz radiation. The terahertz radiation generally involves frequencies between microwave and infrared, such as <NUM> billion hertz to <NUM> trillion hertz. It is appreciated that this terahertz radiation can be used to non-destructively penetrate and image conveyor belts and the like. Thus, two- and three-dimensional maps can be generated for conveyor belts using this technique. The invention provides a system according to claim <NUM>.

<FIG> is a diagram illustrating a system <NUM> for scanning a conveyor belt utilizing terahertz radiation and reflective measurements in accordance with one or more embodiments. The system <NUM> is provided for illustrative purposes and it is appreciated that suitable variations are contemplated.

The system <NUM> utilizes terahertz radiation for conveyor belt diagnostics to identify degradation and the like in a conveyor belt.

The system <NUM> utilizes THz technology in a reflective configuration that is applied for diagnostic non-destructive scanning or monitoring of conveyor belts containing textile or fabric. The system <NUM> can be configured to generate a THz image based on one revolution of the belt using the returned power from reflections from the conveyor belt surface and internal structures to highlight differences in conveyor construction, whether that be for splice monitoring, mold designs (chevrons), embedded structural components or defect morphology. Further, the system can be configured to utilize the time domain of reflections to generate depth details of the conveyor belt morphology.

The system <NUM> can generate a THz image map of one revolution of the belt and analyze this image for splice construction and splice defects that develop over time (between periodic scans or in a permanent system).

Further, the system <NUM> can generate a report of the analysis of this scan (image of one revolution) in order to alert the customer of potential high-risk damages that require 'action' to prevent a catastrophic event or to repair to extend the life of the conveyor belt.

In one example, the system <NUM> is installed as a permanent or fixed monitoring device. For a fixed monitoring device, the system can store a THz image map of one revolution of the belt and analyze incoming data against this image to detect longitudinal rips or new damages in the reinforcing textile layer(s). Further, the system <NUM> can store a THz image map of one revolution of the belt with longitudinal information of health of textile elements or other material components that are embedded between the carcass and bottom (pulley) cover surface at regular intervals, in order to detect longitudinal grooving damage or rip events in these embedded elements. Additionally, a permanent system <NUM> can generate an alarm that can be used to stop the conveyor belt to limit the damage to the conveyor belt.

The system <NUM> includes a transmitter <NUM> and a radiation sensor <NUM> that operate on a conveyor belt <NUM>.

The conveyor belt <NUM> can be a composite of fabric, polymeric material and the like. The belt <NUM> can have one or more splices. The belt <NUM> can include reinforcements, such as fiber, fabric, steel cords and the like.

The conveyor belt <NUM> can include a polymeric top cover material, including but not limited to rubber, PVC, polyurethane and the like, a reinforcing or protective ply (plies)/layer(s) having a fabric/textile layer and a bottom-coated polymeric layer.

Some example compositions of plies/layers for the belt <NUM> include:.

The conveyor belt <NUM> can further include embedded elements to serve as reference to specific locations on the belt <NUM>. The locations include rip inserts, structure elements, edges, and the like. The embedded elements can include radio frequency identification (RFID) tags. This requires the addition of an RFID reading device to detect RFID tags in the belt. This makes it easier for the end user to locate the damage or object of interest identified by the THz scan based on the location. The system <NUM> can be configured to use the embedded elements to facilitate determining locations of identified defects by using corresponding locations as a reference point to the identified defects.

The transmitter <NUM> includes an array of transmitters/field generators configured to generate terahertz radiation and direct the radiation toward a portion of the conveyor belt <NUM>. It is appreciated that the number of generators in the transmitter <NUM> can be one or more. Further, it is appreciated that individual generators can be positioned at selected locations above the belt <NUM>.

The sensor <NUM> includes an array of receivers/sensors configured to measure reflected signals based on the transmitted terahertz radiation. It is appreciated that the number of generators in the receiver <NUM> can be one or more.

The reflected signals have a selected range of reflection from <NUM> to <NUM> THz, based on desired spatial resolution and penetration depth.

The selected frequency range of reflection can be modified/adjusted during operation. For example, the range can be adjusted to image particular layers, depths and sections of the conveyor belt <NUM>.

The circuitry <NUM> is configured to generate conveyor belt characteristics based on the reflected signals. These characteristics can include a full or partial map of the conveyor belt, images, identified wear regions, splits, abrasions and the like.

The circuitry <NUM> can also be configured to read or detect embedded elements, such as RFID tags and the like. In one example, the circuitry <NUM> includes an RFID reader. The detected embedded elements have known locations on the belt <NUM> and can be used to facilitate location of identified defects.

The circuitry <NUM> can also be configured to identify alarm conditions and generate/trigger alarm notifications. The circuitry <NUM> can determine, for example, that the thickness of a layer has reduced below a threshold value, trigger an alarm and generate a notification identifying the defect, the location of the defect and the like. The circuitry <NUM> can determine, as another example, that a splice interface has degraded, trigger an alarm and generating a notification identifying the splice defect, the location of the splice defect and the like.

<FIG> is a diagram illustrating a system <NUM> for scanning a conveyor belt in accordance with one or more embodiments. The system <NUM> is provided for illustrative purposes and it is appreciated that suitable variations are contemplated.

The system <NUM> is substantially similar to the system <NUM> and includes additional details about circuitry <NUM>.

The system <NUM> includes the circuitry <NUM>, a transmitter <NUM> and a receiver <NUM>. The transmitter <NUM> and the receiver <NUM> can be collectively referred to as a terahertz-based sensor array <NUM>.

The circuitry <NUM> is configured to cause the transmitter <NUM> to generate terahertz radiation in the form of fields and/or signals. The circuitry <NUM> is also configured to cause the receiver <NUM> to measure reflected signals based on the generated terahertz radiation. The circuitry <NUM> is configured to generate the belt characteristics of a conveyor belt, such as the belt <NUM>.

<FIG> is a diagram illustrating an arrangement <NUM> of a terahertz sensor array <NUM> in accordance with one or more embodiments.

The sensor array <NUM> includes a transmitter <NUM> and a receiver <NUM>. The sensor array <NUM> can be positioned and/or repositioned about/over the conveyor belt <NUM>.

In this example, the transmitter <NUM> generates radiation towards the belt <NUM> and the receiver <NUM> receives and measures reflected signals via reflection element <NUM>.

<FIG> is a graph <NUM> of conveyor belt measurements based on the terahertz sensor array <NUM> in accordance with one or more embodiments.

The graph <NUM> is a morphological surface plot where the received intensity (measured reflected signals) is converted to a height.

<FIG> is another graph <NUM> of conveyor belt measurements based on the terahertz sensor array <NUM> in accordance with one or more embodiments.

The graph <NUM> is a greyscale plot showing X-position and Y-position (two dimensions) and returned power based on the reflected signals.

<FIG> is a graph <NUM> illustrating a sample spectrum versus a reference spectrum for a range of frequencies in accordance with one or more embodiments.

The horizontal axis is frequency in terahertz (THz). The vertical axis is spectral power in decibels (dB).

Line <NUM> is a reference spectrum based on measurements of air.

Line <NUM> is a sample spectrum based on measurements of a conveyor belt, such as the belt <NUM>.

<FIG> is a diagram illustrating a terahertz sensor array and an example return signal in accordance with one or more embodiments. The array can be used with the systems and embodiments described above.

This example <NUM> is provided for illustrative purposes and it is appreciated that suitable variations are contemplated.

The sensor array includes the transmitter <NUM> and receiver <NUM>, which generally operate as described above.

The transmitter <NUM> generates radiation toward the belt <NUM>. The radiation or signal is labeled T1.

Reflective or return signals, R1 and R2, come from the belt <NUM> and various depths, as shown. R1 is a signal reflected by an upper interface or surface of a first layer or cover. R2 is a signal reflected by a lower inner interface or surface, below the first layer or cover interface. It is appreciated that other reflected signals can be generated by other inner layer interfaces and surfaces.

It is appreciated that an example of a suitable range for transmission is from <NUM> to <NUM> THz due to or based on absorption properties of rubber materials/products. The reflected signal is still subjected to this attenuation effect; thus, a suitable frequency would/should allow maximum or increased transmission while also providing a useful spatial resolution. Hence, the range from <NUM> to <NUM> THz provides both transmission and spatial resolution that is suitable for the detection of belt defects, damages and structures that could impact conveyor performance. According to the invention as claimed, the transmitted radiation is in the frequency range of <NUM> THz to <NUM> THz.

THz reflection imaging is employed as a suitable technique for depth and damage/defect detection. A high index of refraction is advantageous for reflection imaging, as the reflection coefficient, r = (<NUM> - n) / (<NUM> + n), is high for high-index materials. Specifically, for the index of refraction of a typical fabric belt, the reflection coefficient is approximately <NUM>%.

<FIG> depicts the transmitter <NUM> and receiver <NUM> as being at about a <NUM>-degree angle for illustrative purposes. It is appreciated that other suitable geometries are contemplated and may facilitate the condition of reflection and defect identification.

It is appreciated that it is important to balance the amount of signal penetrating the belt <NUM> and the amount of signal reflected by the belt <NUM>. Thus, it is also appreciated that absorption properties of material and layers of the belt <NUM> are considered in selecting frequencies for the transmitter-generated radiation.

For example, at <NUM> THz, the attenuation coefficient is <NUM>-<NUM>. This indicates that the power transmitted through a <NUM> belt would be attenuated by <NUM> dB. At <NUM>, the attenuation would still be <NUM> to <NUM> dB.

The same absorption would apply to the reflected signal; thus, the lower side of the above limit is suitable for this material; thus a <NUM> to <NUM> THz range for the transmitter radiation is suitable. According to the invention as claimed, the transmitted radiation is in the frequency range of <NUM> THz to <NUM> THz.

Separation from signals can provide depth information and indicate defects and the like detected in the structure. Thus, if a first reflection signal is from a top surface, a second reflection is from a lower inner interface, a third reflection signal is from an even lower inner interface and additional reflection signals can occur. Knowledge about the conveyor construction (carry "top" and pulley "bottom" cover gauges, number of fabric plies, splice design are some examples of analysis inputs), allows for these reflections to be analyzed and interpreted.

Power integration data provides the amount of power being returned by the different sections of belt as a whole, and thus provides important morphology or structural information about the belt construction and how it may change at different positions, allowing one to identify potential defects by only using the total returned power from a given location on the belt.

This morphology data can be used to measure characteristics utilized in the manufacture of belt splices where fabrics are cut at specific angles and patterns in order to fabricate a quality splice between the sections of belts that are joined to make a conveyor belt that can be used on a conveyor system. If these splices are of poor quality or are damaged during operation, the belt could tear transversely at this location and generate a catastrophic event that would lead to major downtime for mining operations. It is appreciated that tear can refer to a defect in a transverse direction (across a belt) and a rip in a longitudinal direction (running length).

Examples of belt splices used in fabric/textile belts, include but not limited to the designs shown in <FIG>.

Referring again to <FIG>, the transmitter radiation T1 and reflective signals R1 and R2 illustrate how reflective signals can be used to determine depth and identify conditions at various depths.

Thus, time between pulses can be used to calculate the thickness of a layer by using the refractive index of the material and the frequency of measurement.

This thickness can be used to determine changes in cover thickness and other layer thicknesses of conveyor belts, such as the belt <NUM>.

It is noted that reflections between the top cover and top reinforcement layer would indicate the existence of a reflective structure between the top cover and the reinforcing layer. A later measurement may show a smaller time delay difference, t(R2) - t(R1), which would indicate a loss of material. An increase in this spacing could indicate carcass damage in the area. As such, one would expect the characteristics of a given splice, where fabric belts are spliced together using bias cuts or finger cuts, would be able to be resolved and monitored for potential changes in these splice characteristics over time.

The depth of signals and, therefore thicknesses of layers can be calculated as shown here.

Δt is the time delta between reflected peaks.

n is the refractive index for rubber for a particular frequency - this quantity would be the highest contributor to measurement uncertainty.

<FIG> is a diagram illustrating an example of a splice joint and splicing that can be detected using the system <NUM> and suitable variations thereof.

A conveyor belt, such as the belt <NUM>, is shown having a first section on the left spliced with a second section on the right. In this example, the second section is held tight to a surface while a joining portion of the first section is attached to a joining portion of the second section. In this example, the joining portions are tiered or stepped over a plurality of layers.

<FIG> is a side view illustrating the splice joint of <FIG> in accordance with one or more embodiments.

The joining portion of the first section is shown joined with the joining portion of the second section.

<FIG> is a diagram illustrating a finger-type splice joint in accordance with one or more embodiments.

A conveyor belt, such as the belt <NUM>, is shown having a first section on the left spliced with a second section on the right. In this example, joining portions of each section have matching and interlocking fingers.

<FIG> is a diagram illustrating an example of a conveyor belt that can be used in accordance with one or more embodiments.

This belt can be used as the conveyor belt <NUM>, described above.

The belt is shown with a plurality of layers. The darker-shaded layers are comprised of a polymeric material and the lighter-shaded layers are a fabric reinforcement.

The system <NUM> can be utilized to detect characteristics about each of the layers of the depicted conveyor belt and identify the presence of defects within each layer of the belt or splice.

<FIG> is a diagram illustrating a conveyor belt <NUM> having a support/reinforcing layer in accordance with one or more embodiments. The belt <NUM> is provided for illustrative purposes and it is appreciated that suitable variations are contemplated.

The belt <NUM> can be used as the belt <NUM> of the system <NUM> as shown above.

The belt <NUM>, <NUM> includes a steel reinforcement layer <NUM> having steel cords along a length of the belt.

The belt <NUM>, <NUM> also includes a reinforcement or support layer <NUM>.

The system <NUM> and variations thereof can be configured to identify defects and/or locations for identified defects within the breaker layer <NUM>, the support layer <NUM>, used in steel cords, reinforcing cords (i.e. aramid, nylon, polyester, etc.) and the like.

In addition to that described above, some embodiments of the disclosure could be utilized in conveyor belt applications that have vertical components to monitor vertical structures such as belt walls, cleats, buckets, chevrons, and the like.

Example embodiments are provided so that this disclosure will be sufficiently thorough, and will convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the disclosure, but are not intended to be exhaustive or to limit the disclosure. It will be appreciated that it is within the scope of the disclosure that individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described.

Also, in some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Further, it will be readily apparent to those of skill in the art that in the design, manufacture, and operation of apparatus to achieve that described in the disclosure, variations in apparatus design, construction, condition, erosion of components, gaps between components may present, for example.

Examples can include subject matter such as a method, means for performing acts or blocks of the method, at least one machine-readable medium including instructions that, when performed by a machine cause the machine to perform acts of the method or of an apparatus or system for concurrent communication using multiple communication technologies according to embodiments and examples described herein.

The invention provides a system according to claim <NUM>.

Implementations may include one or more of the features as defined in the dependent claims.

Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

One general aspect, which is not claimed, includes a method of monitoring a conveyor belt. The method of monitoring also includes directing terahertz radiation toward a conveyor belt. The method of monitoring also includes generating reflected signals based on a refractive index and absorption characteristics of the conveyor belt. The method of monitoring also includes measuring the reflected signals by a receiver. The method of monitoring also includes determining belt characteristics based on the measured reflected signals.

Implementations may include one or more of the following features. The method may include determining belt edges, belt structure, presence of defects and splice structural characteristics based on the measured reflected signals. The method may include determining the returned power of the reflected signals to monitor one or more splice joints. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

As it is employed in the subject specification, the term "processor" can refer to substantially any computing processing unit or device including, but not limited to including, single-core processors; single-processors with software multithread execution capability; multi-core processors; multi-core processors with software multithread execution capability; multi-core processors with hardware multithread technology; parallel platforms; and parallel platforms with distributed shared memory. Additionally, a processor can refer to an integrated circuit, an Application Specific Integrated Circuit, a Digital Signal Processor, a Field Programmable Gate Array, a Programmable Logic Controller, a Complex Programmable Logic Device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions and/or processes described herein. Processors can exploit nano-scale architectures such as, but not limited to, molecular and quantum-dot based transistors, switches and gates, in order to optimize space usage or enhance performance of mobile devices. A processor may also be implemented as a combination of computing processing units.

Terms such as "first", "second", and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context.

Spatially-relative terms, such as "inner", "adjacent", "outer", "beneath", "below", "lower", "above", "upper", and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially-relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated <NUM> degrees or at other orientations) and the spatially-relative descriptors used herein interpreted accordingly.

Claim 1:
A system (<NUM>) for monitoring conveyor belts (<NUM>), the system (<NUM>) comprising:
a transmitter (<NUM>) configured to direct terahertz radiation (T1) in a frequency range from <NUM> THz to <NUM> THz towards a conveyor belt (<NUM>);
a receiver (<NUM>) configured to measure reflected signals (R1, R2) based on the terahertz radiation (T1); and
circuitry (<NUM>) configured to determine belt characteristics of the conveyor belt (<NUM>) based on the measured reflected radiation (R1, R2).