Wear detection apparatus and method for comminution devices

Abstract

An apparatus configured to detect wear experienced by a component of a comminution device can be adapted to provide a reliable approach for detecting wear non-invasively to help monitor wear and / or indicate that component may need to be replaced to help facilitate improved maintenance operations that can reduce equipment downtime. Some embodiments can be configured to monitor the wear that may be experienced by a central screw of a tower mill and / or its wear liner in a non-invasive way to provide a real-time monitoring of the wear experienced by that component, for example. The wear detection, or wear monitoring, can be performed while the comminution device is operated to comminute material.

Description

[0001] WEAR DETECTION APPARATUS AND METHOD FOR COMMINUTION DEVICES

[0002] FIELD

[0003] The present innovation relates to apparatuses, systems, and processes configured to detect wear that can occur during comminution of material by a comminution device (e.g. such as mills, tower mills, presses, grinding devices, or other types of comminution devices).

[0004] BACKGROUND

[0005] Mills, presses, crushers, and other types of comminution devices used to grind material often include a crushing body or multiple crushing bodies that are configured to impact material to comminute the material. Examples of such comminution devices may be appreciated from U.S. Patent Nos. 84,978, 252,755, 1,225,061, 1,519,989, 1,589,302, 1,965,186, 3,833,273, 3,955,766, 3,964,717, 4,339,086, 4,369,926, 4,456,267, 4,485,974, 4,582,260, 5,203,513, 5,823,450, 6,523,767, 7,172,144, 9,476,689, and 9,527,087 as well as International Publication Nos. WO 2007 / 101319, WO 2014 / 187824 and WO 2019 / 086577 and U.S. Patent Application Publication No. 2020 / 0209128. Components of comminution devices can experience wear as a result of the comminution of material.

[0006] SUMMARY

[0007] We have determined that some types of comminution devices do not have any convenient way to monitor wear that may occur as a result of comminution of material. For example, we are unaware of any type of method of determining what the wear on the central screw liner for a tower mill that does not require draining the tank of the tower mill to remove the slurry and grinding media from the mill and opening of the mill to perform measurements on the screw of the mill to evaluate how the screw or its liner has experienced wear. For example, there are no real-time measurements of the wear on the screw nor any type of non-invasive approach for monitoring the wear that may be experienced by the screw or its protective liner.

[0008] Embodiments of our apparatuses, systems, and processes can be configured to detect wear that can occur during comminution of material by a comminution device and can be adapted to provide a reliable approach for detecting wear non-invasively and in real-time to help monitor wear and / or indicate that one or more components may need to be replaced to help facilitate improved maintenance operations that can reduce equipment downtime. The wear detection can occur while the comminution device is being operated to comminute material so the wear detection, or wear monitoring, does not interfere with comminution device operation.

[0009] We have surprisingly found that embodiments of our apparatuses, systems, and processes can provide for externally monitoring internal screw wear in tower mills, which are typically considered an electromagnetically shielded environment due to the steel balls that are commonly used as media in the mill. The steel balls were conventionally believed to block most signals that would permit a remote, external monitoring within the comminution chamber of a tower mill. We have surprisingly found that embodiments of our sensor can be positioned external to a comminution chamber so that wear of a screw of a tower mill can be measured and monitored to detect when the liner of the screw and / or screw has sufficiently worn away to require maintenance. Embodiments can be configured for providing such measurement data even when the tower mill is operating to comminute material and steel balls or other material are in the comminution chamber during rotation of the screw and comminution of particulate material.

[0010] Some embodiments of our apparatuses, systems, and processes can be configured to monitor the wear that may be experienced by a central screw of a tower mill and / or its wear liner in a non-invasive way to provide a real-time monitoring of the wear, for example. For example, some embodiments can utilize at least one sensor to provide real-time data on tower mill screw liner thickness and diameter that can improve the ability to target changeout dates based on the actual wear of the screw. Improved scheduling of changeouts can result in less waste as a changeout may only occur after a screw (or its liner) has sufficiently worn to warrant a replacement, or changeout. Also, the providing of real-time information about the wear of the screw can decrease the need to take the mill offline, which decreases personnel costs and downtime for the operator of the mill as well.

[0011] In some embodiments, a comminution apparatus can include at least one wall defining a comminution chamber and a rotatable screw positioned within the comminution chamber. Rotation of the screw can drive comminution of particulate material within the comminution chamber. At least one sensor can include a first sensor positioned external to the comminution chamber adjacent to or integrated within the at least one wall. The first sensor can be positioned and configured to detect and / or monitor wear of the screw.

[0012] In some embodiments, the first sensor can include at least one coil positioned in a housing that includes a non-ferromagnetic portion of the housing between the at least one coil and the comminution chamber. In some configurations, there can be a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal that corresponds to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw. In some embodiments, the first coil can be positioned horizontal or vertical or any angle in between

[0013] In some embodiments, the first sensor can include at least one coil comprising multiple runs of insulated metal wire to define an annular shaped multi-layer coil. The insulated metal wire may, for example, be positioned around a reformer such as a winder, spool, reel, die, mold, form, annular member, or the like, for example, to hold a shape of the insulated metal wire or insulate it or provide additional structural rigidity to the same, without limitation. The annular shaped multi-layer coil may comprise an air core or a magnetic core, without limitation. A portion of a housing that is a non-ferromagnetic and / or non-conductive can be positioned between the annular shaped multi-layer coil and the comminution chamber. This nonferromagnetic or non-conductive portion may comprise, for example, an adhesive, an epoxy, a potting material, a polymeric portion of the housing, or a polymeric liner portion of the at least one wall, without limitation. A thin ferromagnetic, conductive, or metallic portion may be provided between the at least one sensor and the comminution chamber, without limitation. The thin ferromagnetic, conductive, or metallic portion may comprise a portion of the at least one wall, without limitation. The first sensor can be configured so that the housing of the first sensor is connected to the at least one wall. In some configurations, the first sensor can be integrated into the wall or otherwise attached to the wall that defines the comminution chamber.

[0014] Embodiments can also include a computer device communicatively connected to the first sensor. At least one coil of the first sensor can be connected to a detector device configured to measure electrical impedance, inductance, and / or resistance of the at least one coil. The computer device can be communicatively connected to the detector device to receive data of the detector device, monitor that data, and / or analyze that data.

[0015] Embodiments of a sensor for a comminution apparatus can be provided as well. The sensor can be positionable external to a comminution chamber of the comminution device adjacent to or integrated within at least one wall of the comminution device defining the comminution chamber. The sensor can be configured to detect and / or monitor wear of a rotatable screw positioned within the comminution chamber. The sensor can include at least one coil positioned in a housing that includes a nonferromagnetic portion of the housing between the at least one coil and the comminution chamber. In some embodiments, the at least one coil can include a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal that corresponds to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw. In some embodiments, the first sensor of the comminution apparatus may comprise at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle which does not substantially correspond to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw.

[0016] In some embodiments, the first sensor of the comminution apparatus may comprise at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal which is not equal to 0°.

[0017] In some embodiments, the at least one coil can include a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal that can vary between 0 and 90 degrees. For example, in some embodiments, the first sensor of the comminution apparatus may comprise at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal which is between 5° and 60°, for example, at an angle between 5° and 45°, without limitation. In some embodiments, the first sensor of the comminution apparatus may comprise at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal which is between 5° and 85°, such as an angle between 10° and 80°. In some embodiments, the first sensor of the comminution apparatus may comprise at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal which is between an angle between 10° and 75°, such as at an angle between 10° and 70°, an angle between 15° and 75°, an angle between 20° and 70°, an angle between 25° and 75°, an angle between 20° and 60°, an angle between 30° and 60°, an angle between 40° and 70°, an angle between 15° and 45°, an angle between 30° and 50°, or an angle between 30° and 40°, without limitation. As stated above, the angle may be selected to correspond to or not correspond to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw.

[0018] In some configurations, the at least one coil can include multiple runs of insulated metal wire to define an annular shaped multi-layer coil. The insulated metal wire may, for example, be positioned around a reformer such as a winder, spool, reel, die, mold, form, annular member, or the like, for example, to hold a shape of the insulated metal wire or insulate it or provide additional structural rigidity to the same, without limitation. The annular shaped multi-layer coil may comprise an air core or a magnetic core, without limitation. A portion of housing that is a non-ferromagnetic and / or non-conductive of the sensor can be positioned between the at least one coil positioned in the housing and the comminution chamber. This non-ferromagnetic or non-conductive portion may comprise, for example, an adhesive, an epoxy, a potting material, a polymeric portion of the housing, or a polymeric liner portion of the at least one wall, without limitation. A thin ferromagnetic, conductive, or metallic portion may be provided between the at least one sensor and the comminution chamber, without limitation. The thin ferromagnetic, conductive, or metallic portion may comprise a portion of the at least one wall, without limitation. A process for detecting wear of at least one component of a comminution device can also be provided. Embodiments of this process can include monitoring a thickness of the distal screw edge and / or a distance between a distal edge of a screw within a comminution chamber of the comminution device and a wall of the comminution device that defines the comminution chamber. In response to detecting that an effect of the distance and / or thickness is at or beyond a pre-selected threshold, scheduling maintenance work to address wear experienced by the screw.

[0019] In some embodiments, the distal edge of the screw can be a distal edge of a blade of the screw or a liner of the blade of the screw. The monitoring of the wear can be performed by a sensor positioned external to the comminution chamber. Exemplary embodiments of the sensor are discussed herein, for example.

[0020] The monitoring of the thickness and / or the distance can include monitoring over time an electrical impedance, inductance and / or resistance of at least one coil of a sensor to determine a change in the distance and / or the thickness and analyzing a time-series of monitored electrical values in combination with a known or measured rotation speed of the screw to determine how the screw has experienced wear based on the electrical values.

[0021] Embodiments of the sensor and embodiments of the comminution apparatus can be utilized n embodiments of the process. For instance, embodiments of the apparatus can be configured to implement an embodiment of the process.

[0022] Other details, objects, and advantages of the invention will become apparent as the following description of certain exemplary embodiments thereof and certain exemplary methods of practicing the same proceeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Exemplary embodiments of a comminution device, an apparatus configured to detect wear of at least one component of the comminution device, a process for detecting wear of at least one component of a comminution device, and methods of making the same are shown in the accompanying drawings. It should be understood that like reference numbers used in the drawings may identify like components.

[0024] Figure 1 is a schematic view of a first exemplary embodiment of a comminution device having a first exemplary embodiment of an apparatus configured to detect wear of the comminution device.

[0025] Figure 2 is a schematic view of the first exemplary embodiment of an apparatus configured to detect wear of the comminution device that can be included in the first exemplary embodiment of a comminution device shown in Figure 1.

[0026] Figure 3 is a schematic fragmentary view of the first exemplary embodiment of a comminution device having the first exemplary embodiment of an apparatus configured to detect wear of the comminution device., which illustrates a positioning of a sensor 21 which includes a housing 21 h and at least one coil 21c with a long axis L at an angle A relative to horizontal H.

[0027] Figure 4 is a schematic illustration to provide an example illustration of a coil 21c of a sensor 21 overlaid a portion of a blade 5b to help illustrate how an angle A at which a coil’s longest axis L can extend relative to horizontal H can correspond to the angle at which the blade(s) 5b of the screw 5 are angled relative to horizontal H as the blades 5b extend along the vertical shaft 5s of the screw. Figure 5 is a block diagram of an exemplary embodiment of a computer device CPU that can be communicatively connected to the sensor 21 and can be utilized in the first exemplary embodiment of the apparatus configured to detect wear of the comminution device.

[0028] Figure 6 is a flow chart illustrating an exemplary embodiment of a process for detecting wear of at least one component of a comminution device.

[0029] DETAILED DESCRIPTION

[0030] Referring to Figures 1-5, a comminution device 1 can include a base 2 that includes a mill shell assembly 3 that is positioned and configured to define a comminution chamber 3 c. The mill shell assembly 3 can have a bottom 3b to which at least one sidewall 3w is attached. Each sidewall 3w can extend from the bottom 3b to define the comminution chamber 3c. The mill shell assembly 3 can include a moveable access door 3d that can be adjusted between an enclosed position to an open position. The access door 3d can be moveable as indicated by arrow 4 in Figure 1, for example, between the enclosed position and open position and vice versa. The access door 3d can include a sidewall 3w or sidewall segment that can be moved relative to another sidewall or sidewall segment via a hinged connection or other moveable connection, for example. In its enclosed position, the access door 3d can be positioned to enclose a vertically elongated helical screw 5 within the comminution chamber 3 c for comminution of material. In its opened position, the access door can be moved away from the other sidewall(s) 3w or sidewall segments to open the comminution chamber 3 c to provide access to the interior of the comminution chamber 3 c and screw 5.

[0031] The comminution device 1 can be configured to comminute a material such as a mineral, an ore, rock, stone, agglomerated material, cement clinker, cement raw meal, or other type of material. For example, the screw 5 can include threads or blades that helically extend around a vertically elongated shaft. A liner can be positioned over the exterior of the screw 5 for directly contacting slurry and / or particulate material when rotating within the comminution chamber 3 c to comminute material.

[0032] Comminution media from a media chute 7 can be fed to the comminution chamber 3 c to facilitate comminution as well. The comminution media can help facilitate comminution of material. The comminution media can include, for example, steel bodies, metal bodies, or other types of bodies. In some embodiments, the media can be spherical and / or have other shapes.

[0033] The comminution media from the media chute 7 can be fed to the comminution chamber 3 c via a comminution media feed conduit 8 connected to the chute 7 so that comminution media can pass from the chute 7 through the comminution media feed conduit 8 and into the comminution chamber 3 c via a comminution media feed chute outlet 8o that is positioned to feed media passed through the comminution media feed conduit 8 into the comminution chamber 3 c.

[0034] The mill shell assembly 3 can also define an inlet 3i for feeding material to be comminuted and / or fluid into the comminution chamber 3c. For example, a slurry containing particulate material (e.g. water or other liquid having particulate material to be comminuted entrained therein) can be fed into the comminution chamber 3c via the inlet 3i. A feed conduit can be connected to the inlet 3i to feed material to be comminuted into the comminution chamber 3c.

[0035] As another example, liquid can be fed into the comminution chamber 3 c and thereafter material to be comminuted can be fed into the comminution chamber 3c via the inlet 3i. A pump or compressor can be connected to a feed conduit to help feed the material into the comminution chamber 3c via the inlet 3i in some embodiments. The comminution of material can be facilitated via rotation of the screw 5. After the comminution media and particulate material to be comminuted are included in liquid within the comminution chamber 3 c, the screw 5 can be rotated to facilitate comminution of the particulate material. For instance, the particulate material can be comminuted via attrition that can occur as a result of the comminution media within the slurry being moved via rotation of the screw 5 to help break up the particulate material into a smaller size. Once the particulate material is of a sufficiently smaller size, it can pass between the comminution media within the slurry and rise to a top of the liquid within the comminution chamber 3 c for being output from the comminution chamber 3c via an upper outlet 3o defined in a sidewall 3w.

[0036] The one or more sidewalls 3w can have a liner 3L that covers at least a portion of each sidewall to help preserve the sidewall 3w (e.g. the liner 3L can wear and be replaced without having to replace the sidewall 3w). The liner 3L can be positioned on an inner side of each sidewall 3w and face the comminution chamber 3c for direct contact with liquid, comminution media, and / or particulate material within the comminution chamber 3 c that can move as the screw 5 rotates to comminute the particulate material into smaller sized material.

[0037] The rotation of the screw 5 can be driven by a main drive motor 9 that can be connected to the screw 5. For instance, a drive shaft 6 can be connected between the screw 5 and the main drive motor 9 so that rotation of the drive shaft 6 driven by the motor can cause the screw 5 to rotate within the comminution chamber 3 c. The drive shaft 6 can be connected to the motor 9 via a plurality of connection mechanism so the drive motor can cause rotation of the drive shaft 6. For instance, lower bearing assembly 10a, upper bearing assembly 10b, low speed coupling 10c, planetary gear reducer lOd, and high-speed coupling lOe can be positioned and arranged to help connect the drive motor 9 to the drive shaft 6 for driving rotation of the drive shaft 6 for rotation of the screw 5 connected to the drive shaft 6.

[0038] Lubricant can be provided to support the motion of the drive motor 9, drive shaft 6, and various connectors facilitating the connection between the drive shaft 6 and drive motor 9 for driving rotation of the screw 5. For example, a lubrication unit 11 can be connected to these elements to facilitate the distribution of lubricant (e.g. lubricating oil, etc.) via lubrication piping 12 connected between the lubrication unit 11 and the various elements to which the lubrication unit 11 is connected to provide lubricant to support the drive motor 9 and its connection to drive shaft 6 for driving rotation of the screw 5. The lubrication unit can include a pump, lubricant reservoir, and / or other elements to supply lubricant to these different elements via the lubrication piping 12.

[0039] The screw 5 can include one or more helical blades 5b that can extend helically along a shaft 5s of the screw 5. Each helical blade 5b can extend along an angle of inclination or angle of declination along the shaft 5s. Rotation of the screw 5 in the comminution chamber 3 c can cause each of the blades 5b connected to the shaft 5s to be rotated about the vertical axis defined by the shaft 5 s of the screw 5. This rotation can agitate the liquid, comminution media, and particulate material within the comminution chamber 3 c for comminution of the material therein to reduce the size of that material. In some configurations, the material can be fed into the comminution chamber at a first pre-selected size (e.g. 100 micrometers in size, between 200 micrometers and 50 micrometers in size, etc.) and can be comminuted to a smaller second preselected size (e.g. 20 micrometers, between 30 micrometers and 10 micrometers, 20 micrometers and smaller, etc.). The comminution device 1 can also include at least one sensor 21 that is positioned within or adjacent a sidewall 3w to measure the extent to which the liner of the helical blade(s) 5b wears during comminution. For example, when the access door 3d is in its enclosed position and the screw 5 is rotated to comminute material, the sensor 21 can be powered within the sidewall 3w to wireless detect and / or monitor the extent to which the liner of the blade(s) 5b wear. The sensor 21 can be communicatively connected to a computer device CPU to provide its measurement data to the computer device CPU so that a worn condition of the one or more blades 5b can be identified. In response to detection of that condition, the sensor 21 and / or the computer device CPU can be configured to emit output to indicate scheduling for maintenance should occur for the screw 5. The emitted output can include an audible warning emitted via a speaker, and / or a visual warning displayed via at least one output device (e.g. a text warning or visible indicia warning displayed via a display device or other output device of the computer device CPU).

[0040] The sensor 21 can be positioned external to the comminution chamber 3 c. For example, the sensor 21 can be positioned in a sidewall 3w away from the liner 3L or can be coupled to an outer portion of the sidewall 3w. The sensor 21 can be configured to wirelessly characterize the wear of the screw 5 during comminution even while metal comminution media may be present within the comminution chamber 3c during comminution operations.

[0041] In some embodiments, the sensor 21 can be positioned to monitor a bottom half or bottom third of the comminution chamber 3 c. For instance, in embodiments where it is contemplated that the most wear to be experienced by the screw 5 will be near the bottom of the comminution chamber 3 c, the sensor 21 can be positioned to monitor the bottom half or bottom third of the comminution chamber 3 c for monitoring the wear that can be experienced by the screw 5 in this region of the comminution chamber 3 c.

[0042] In some embodiments, the sensor can include at least one coil 21c positioned within a housing 21 h that is connected to a sidewall 3w or integrated into the sidewall 3w and external to the comminution chamber 3c. The housing 21h can include a low- conductivity, nonferromagnetic material (e.g. 300-series stainless steel), which can help permit the housing 21h of the sensor 21 to avoid interfering with the measurement that the coil 21c can provide (or help minimize any such interference). The housing can also include ferromagnetic material to act as a core, shielding, and / or back-iron for the coil 21c.

[0043] Some embodiments can utilize a single coil 21c. Other embodiments can utilize multiple coils 21c (e.g. a first coil and a second coil, a first coil, a second coil, and a third coil., etc.). When multiple coils are utilized, the coils can be arranged in a vertically spaced apart column within the housing 21h. Each coil 21c can be annular shaped (e.g. oval-shaped, ring-shaped, etc.).

[0044] Each coil 21c can have a diameter. In situations where the coil 21c is an oval or ellipse shaped annular structure, the coil 21c can have a major diameter that extends along a longest axis of the coil 21 (axis L shown in Figure 3). This longest axis can be considered the longest part of the coil, or its semi-major axis. As may best be seen in Figure 3, each coil 21 can be arranged so that its longest axis L is angled relative to horizontal H via an angle A. The angle A can be selected to correspond to an angle at which the blade(s) 5b of the screw are angled relative to horizontal H as the blades 5b extend along the vertical shaft 5 s of the screw. A schematic illustration of this corresponding angle A at which the longest axis L of the coil 21c extends that corresponds to the angle at which the blade(s) 5b extend is shown in Figure 4 to help illustrate how the angle A at which the longest axis of the coil 21 can extend relative to horizontal H can correspond to the angle at which the blade(s) 5b extend relative to horizontal.

[0045] In some configurations, the angle A can be a 20° angle relative to horizontal or an angle between 10° and 30° relative to horizontal H for corresponding to the angle at which the blade(s) 5b extend relative to horizontal along the shaft 5s. Other embodiments can utilize a different angle A that may correspond to the angle at which the blade(s) 5b extend relative to horizontal H along the screw shaft 5s (e.g. an angle of between 5° and 45° or an angle of between 5° and 60°, etc.).

[0046] Each coil 21c can be configured as a multilayer coil on a reformer. The reformer may comprise an annular shape, for example, a rectangular shaped, an oval shaped, a circular shaped, or a polygonal shaped reformer, without limitation. Wire used to form the multi-layer coil 21c can be enamel-coated copper wire or other type of insulated highly-conductive wire that can be suitable for a pre-selected set of design criteria. In some embodiments, it is contemplated the coil can be a single wire extended in an annular shape. However, it is preferred that the coil be a multi-layer coil including multiple runs of wire to define the annular shape of the coil 21c. The wire of the coil can be a metal wire (e.g. copper wire, etc.).

[0047] Each coil 21c can be configured as an inductor coil. The inductor coil 21c can be configured to receive voltage and / or electrical current to generate an alternating magnetic field that extends into the comminution chamber 3 c to detect a distance of a gap G that extends between a distal edge of the blade(s) 5b and the liner 3L of the wall(s) 3w that define the comminution chamber 3 c. The distance of this gap G can expand to a larger size over time as the liner of the screw blade(s) 5b wear away (e.g. via rotation that results in frictional contact with liquid of the slurry as well as comminution media and / or particulate material within the liquid that is being comminuted). In an exemplary configuration, the size of the coil 21c is large enough so that the relative strength of the magnetic field at the distance of the blade 5b is large enough that the effect of the blade 5b on the field can be reliably measured. The smallest diameter of the coil 21c can be selected so that it is greater than or not much smaller than the distance between the coil 21c and the distal edge of the blades 5b.

[0048] The sensor 21 can be configured to remotely detect the thickness of the remaining material on the tower mill screw liners (e.g. liner of the blade 5b). In response to a determination that the gap G has grown to a size that is at or larger than a pre-selected wear threshold size, maintenance for the comminution device can be scheduled for a convenient time that can permit comminution operations to cease and repair work or screw liner replacement work to be performed. The sensor 21 can respond simultaneously to the combined effect of growth of the distance of the gap G and of reduction in the thickness of the screw liners.

[0049] In some configurations, each coil 21c can be connected to detector device(s) (e.g. an LCR meter, precision resistor, analog-to-digital converter, multimeter, or other type of appropriate detector device) that can evaluate the complex impedance or equivalent inductance (L), capacitance (C), and / or resistance (R) of the coil 21c as it interacts with the comminution device 1 and detect changes that may occur in these quantities over time as the comminution device 1 is in operation and the screw 5 is rotated for comminution of material. For example, the detector device (e.g. LCR meter) can detect the equivalent resistance and / or inductance of the coil 21c in generating an alternating magnetic field that extends into the comminution chamber 3 c throughout the life of the screw liners for the blade(s) 5b and / or screw 5.

[0050] The detector device(s) may use an alternating voltage / current signal with a fixed excitation frequency to generate the alternating magnetic field with the coil 21c. The excitation frequency can be selected so that it is low-enough to interact with the blade liners without being shielded by the wall(s) 3w, liner 3L, or comminution media inside the comminution chamber 3c. For instance, the frequency of the excitation can be below 25 Hz. Multiple excitation frequencies can be used. In an alternate embodiment, the coil 21c can be driven with a fixed direct current source and the voltage across the coil 21c can be monitored to detect changes in the voltage associated with the rotation of the blade 5.

[0051] The data from the detector device can be used to estimate the size of the gap G and thickness of the screw liners for the blades 5b and to provide data on how these measurements change over time with increasing wear. Such data can be fed to a computer device CPU, which can be an operator device or other type of computer device (e.g. controller, laptop computer, workstation, desktop personal computer, etc.) that is communicatively connected to the detector device and / or coil 21c of the sensor 21 to receive data for recording the data and / or determining the electrical properties (e.g. equivalent inductance and / or resistance) of the coil 21c and how those can correlate to an extent to which the screw’s liner or blade liner has worn as comminution of material occurs via rotation of the screw 5. The computer device CPU can transmit the data so that it can be viewed and evaluated by a technician, engineer, or operator for calibration of the sensor 21 or for evaluation of the wear of the screw’s liner or blade liner.

[0052] In some configurations, the sensor 21 can be connected to an operator device that can be a component of an automated process control system to provide real time data on screw liner thickness based on the monitored distance of the gap G providable via the sensor 21, for example. Such data can be output via at least one output device of the operator device (e.g. a computer device CPU). Such an output of data can occur via a printer or via a display, for example. In some embodiments, the data obtained via the sensor 21 or coil 21c can be filtered to account for noise in the signal received at the sensor 21. For instance, a Fast Fourier Transformation can be utilized to filter noise in the signal received by the sensor 21. Active or passive analog filters can be used to remove unwanted high-frequency, low-frequency, and / or direct-current content from the signal. A Non-Uniform Fast Fourier Transform or other digital signal processing techniques can be used to identify the phase and magnitude of voltage / current across the coil 21c of the sensor signal that matches the excitation frequency. This type of filtering or signal processing can occur via a filter device of the sensor 21 and / or via a filter mechanism of the computer device CPU that receives the sensor’s data.

[0053] The coil 21c can be wired electrically in series and / or parallel with components of known impedance so that the phase and magnitude of the signal across the coil 21c can be compared to the phase and magnitude of the input signal. By comparing the magnitude and phase shifts of the voltage / current across the coil 21c, and the voltage / current across the other components of known impedance at a given excitation frequency, the complex impedance (i.e. equivalent inductance and resistance) of the coil can be calculated. This calculation can be done digitally or its effect can be evaluated through an analog circuit (e.g. a Maxwell bridge).

[0054] In some embodiments, a time-series of the coil 21c complex impedance can be analyzed to identify or isolate the effect of the rotating blade 5 on the complex impedance. The measurements of phase and magnitude from sensor 21 can be analyzed with a sliding time window to generate the time-series of the coil 21c complex impedance. The time-series of complex impedance can be analyzed with a Fast Fourier Transform, a Non-Uniform Fast Fourier Transform, wavelet transform, spectral analysis and / or other digital signal processing techniques.

[0055] The time-series can be analyzed to identify the magnitude of the periodic effect of the rotating blade 5 on the complex impedance of the coil 21c. The analysis can use the known or measured rotation speed of the blade to aid the analysis of the time-series. For example, if a double-helix blade 5 is rotating at 30-revolutions-per-minute, the blade liner of the helical blade 5b can pass the coil 60-times-per minute and generate a periodic effect on the complex impedance of the coil that repeats every second. The duration of time used in the time-series analyzed to identify the effect of the blade on the complex impedance can be longer than several or many revolutions of the blade so that the effect of the revolution can be averaged and / or extracted from noisy measurements. This type of time-series analysis with a known or measured rotation rate can be used to compensate for drift in the sensor 21 measurements that are unrelated to changes in the size of the gap G and thickness of the screw liners for the blades 5b.

[0056] In some embodiments, more than one sensor 21 could be utilized. For instance, a first sensor 21 can be positioned in a first location adjacent the comminution chamber 3c and a second sensor 21 can be spaced apart from the first sensor and positioned at a second location adjacent the comminution chamber. Each sensor 21 can be remote from the comminution sensor 3 c and positioned to wirelessly monitor wear via monitoring of the effect of a size of a gap G and thickness of the liners of the blade 5b as discussed above. In some configurations, each sensor can be spaced vertically from each other (e.g. at different height locations along the same portion of a sidewall 3w) and / or horizontally from each other (e.g. opposite sides of the shell assembly 3). In other embodiments, only a single sensor 21 may be utilized.

[0057] In some embodiments, it is contemplated that use of multiple sensors 21 in which first and second sensors are located on opposite sides of the comminution chamber 3 c (external to the chamber and remote from the chamber), can allow for acquisition of sufficient data for better smoothing out a phase shift in the signal that may be detected by the coils 21c of the sensors 21. In some embodiments, it is contemplated that use of multiple coils 21c in which first and second coils are located so as to magnify the effect of the blade 5 rotation on a combined signal. For example, the two coils 21c could be oriented on the cylinder such that an increase in the complex impedance of one coil 21c due to the rotation the blade 5 occurs simultaneously with a decrease in complex impedance of the other coil. This simultaneous but opposite-signed shift can be caused by the blade 5 rotating into the alternating magnetic field of one coil 21c and out of the alternating magnetic field of the other. The two coils can be wired electrically in series and the voltage at the electrical junction of the two coils can be measured and compared to the input signal. This configuration can make the effect of the blade 5 rotation stronger in the signal.

[0058] As discussed above, each coil 21c of each sensor 21 can be optionally oriented to be inclined to align its longitudinal axis (e.g. longest axis L) with the slope of the blade(s) 5b of the screw 5. However, other embodiments can utilize other suitable arrangements and orientations (e.g. the sensor’s longest axis L can extend horizontally or can extend at an angle A that sufficiently differs from the angle at which the blade(s) 5b may extend, etc.)

[0059] Also, embodiments of the sensor 21 can be configured for integration into a wall 3w in a way that can provide improved penetration of the alternating magnetic field. For example, at the location at which the sensor 21 is positioned, the wall 3w can be constructed so that there is no ferromagnetic material between the coil 21c of that sensor 21 and the comminution chamber. For example, a non-metallic or low-conductivity non-ferromagnetic housing 21 h can be attached to the wall 3w via bolts or other fasteners at spaced apart locations that avoid ferromagnetic material being located between the coil 21c and the comminution chamber for providing an improved penetration of the alternating magnetic field created by the coil 21c. As discussed above, data from the sensor 21 can be provided to at least one computer device CPU that can be communicatively connected to sensor 21. The communicative connection can be a network connection or other type of communication connection (e.g. wireless local area network connection, wired network connection, direct wired communication connection, near field communication connection, cellular network connection, etc.). The computer device can be configured as a controller or an operator device (e.g. laptop computer, personal computer, tablet, smart phone, etc.) in some embodiments.

[0060] As may best be seen in Figures 2 and 5, the computer device CPU can include a processor (Proc.) communicatively connected to at least one interface and at least one non- transitory memory (Mem.). The memory can have at least one application (App) and at least one data store (DS) stored thereon. Each data store DS can be a file, data from the sensor, a database, or other type of data or file.

[0061] The computer device CPU can also be communicatively connected to at least one input device, at least one output device, and / or at least one input / output device (VO Device). Examples of an output device include a speaker, a display, or a printer. Examples of an input device include a microphone, a keypad, a keyboard, a pointer device, and / or a touch screen display. An example of an input / output device can include a touch screen display.

[0062] In some embodiments, the computer device CPU can be communicatively connectable to other computer devices (e.g. an automated process control system that can be configured to monitor or control operation of the comminution device 1 and / or plant having the comminution device 1, other devices of a network, etc.).

[0063] As noted above, in some embodiments the computer device CPU can be configured to receive signal data acquired by the one or more coils 21c of the sensor 21 and store that data. The data can optionally be filtered prior to storage and / or use. The collected data can be utilized to detect wear experienced by the screw 5. For instance, the change in equivalent inductance or resistance of the coil can be tracked and correlated with an increase in the size of the gap G or reduction in the thickness of the blade liners 5b to indicate an extent to which the screw 5 has experienced wear during comminution operations. This data can be collected while comminution operations are being performed. The computer device CPU can be configured to utilize such data to detect a wear condition of the screw 5 and provide output to an operator to indicate the current state of the screw, a graph or other visual that depicts how the screw has experienced wear over a period of time, and / or a warning or notification to indicate the it has been determined from the sensor data that the screw has experienced sufficient wear to require maintenance or to need to have maintenance performed relatively soon.

[0064] In other embodiments, the sensor 21 can be configured to collect data concerning the wear experienced by the screw and, in response to detecting that the screw has experienced sufficient wear, communicating an alert or notification to a computer device CPU to indicate that the screw 5 has experienced sufficient wear to need to have maintenance work performed on the screw 5.

[0065] An exemplary embodiment of a process for evaluating how a screw of a tower mill has experienced wear is shown in Figure 6. The process of Figure 6 is an exemplary embodiment of a process for detecting wear of at least one component of a comminution device. As shown in Figure 6, a first step SI of the process can include monitoring the wear of the blade liners of a distance between an inner wall 3w of the mill shell assembly 3 (e.g. the combined effect of distance to the distal edge of a blade 5b and the thinning of the blade 5b). The monitoring can be performed by the sensor 21 and / or computer device CPU as discussed above, for example. 1 In a second step S2, measured wear that is at or above a pre-selected threshold can be detected. This determination can be based on evaluation of sensor data as discussed above.

[0066] In a third step S3, maintenance can be scheduled to replace the worn component(s) to account for the detected wear condition. This type of work can include replacing or fixing the screw liner and / or liner of the blade 5b of the screw 5, for example. In a fourth step S4, the comminution device operation can be stopped and maintenance can be performed to address the wear condition. In some embodiments, this can include emptying the comminution chamber of liquid, comminution media, and particulate material and moving the access door 3d to an open position so personnel can access the screw to work on the screw liner and / or liner 3L of the wall(s) 3w.

[0067] After the maintenance work is finished, the access door can be closed to position it in its enclosed position, liquid, comminution media, and particulate material can be fed to the comminution chamber 3c, and the screw 5 can be rotated to re-start comminution operations. The sensor 21 can be re-calibrated with the information that the liners on the screw 5 are pristine at that time. The sensor 21 can then be activated to resume monitoring of wear (e.g. the process can return to the first step SI, etc.).

[0068] It should be appreciated that embodiments of the sensor 21 can be configured to provide real-time data on screw wear to an operator device or other type of computer device for use in monitoring how the screw 5 and / or its liner is experiencing wear during comminution operations. This type of data can be used to permit an operator to accurately assess wear in a non-invasive manner to target changeout dates based on the actual wear of the screw, which can provide better changeouts that are only made when actually needed, which can result in less material waste (e.g. avoidance of a changeout when a liner still has useful life) and also help limit operational downtime (e.g. by reducing the number of changeouts that may be scheduled due to the acquisition of actual wear data while comminution operations are ongoing). By decreasing the need to take the screw 5 offline to undergo liner changeouts or other wear related preventive maintenance can decrease personnel costs and downtime for the operator of the comminution device 1.

[0069] It should be appreciated that embodiments of the comminution device, apparatus configured to detect wear, process for detecting wear, and method of making and using the same can be modified to meet different sets of design criteria. For instance, the size and shape of the comminution device can be any of a number of different shapes to meet a particular design objective. The material composition of components of the comminution device (e.g. wear liner of a screw, etc.) can be a number of different materials, such as metal, alloy, or other type of material as may be needed to meet a particular set of design criteria. In some particular nonlimiting embodiments, a high chrome white iron may be employed as a preferred material for a blade portion 5b of the screw 5, as this material may provide both beneficial wear and beneficial electromagnetic properties for improved sensing. As yet another example, it is contemplated that the comminution device can be configured as a tower mill or may be configured as another type of comminution device or other type of mill that may utilize a rotatable screw, blade, or agitator to facilitate comminution of material.

[0070] While certain exemplary embodiments of the comminution device, apparatus configured to detect wear, process for detecting wear, and methods of making and using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

What is claimed is:

1. A comminution apparatus comprising: at least one wall defining a comminution chamber; a rotatable screw positioned within the comminution chamber, rotation of the screw driving comminution of particulate material within the comminution chamber; at least one sensor comprising a first sensor positioned external to the comminution chamber adjacent to or integrated within the at least one wall, the first sensor positioned and configured to detect and / or monitor wear of the screw.

2. The comminution apparatus of claim 1, wherein the first sensor comprises: at least one coil positioned in a housing that includes a non-ferromagnetic and / or non- conductive portion of the housing between the at least one coil and the comminution chamber.

3. The comminution apparatus of claim 1 or 2, wherein a thin ferromagnetic, conductive, or metallic portion is provided between the at least one sensor and the comminution chamber.

4. The comminution apparatus according to any one of the preceding claims, wherein the first sensor comprises: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal that corresponds to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw.

5. The comminution apparatus according to any one of claims 1-3 or 5, wherein the first sensor comprises: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle which does not substantially correspond to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw.

6. The comminution apparatus according to any one of the preceding claims, wherein the first sensor comprises: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal which is not equal to 0°.

7. The comminution apparatus according to any one of the preceding claims, wherein the first sensor comprises: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal, the angle being between 5° and 60°.

8. The comminution apparatus according to any one of the preceding claims, wherein the first sensor comprises: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal, the angle being between 5° and 45°.

9. The comminution apparatus according to any one of the preceding claims, wherein the first sensor comprises: at least one coil comprising multiple runs of insulated metal wire defining an annular shaped multi-layer coil.

10. The comminution apparatus according to claim 9, wherein the annular shaped multi-layer coil comprises an air core or a magnetic core.

11. The comminution apparatus according to any one of the preceding claims, wherein the housing is connected to the at least one wall.

12. The comminution apparatus according to any one of the preceding claims, comprising a computer device communicatively connected to the first sensor.

13. The comminution apparatus according to any one of the preceding claims, wherein the first sensor comprises: at least one coil connected to a detector device configured to measure electrical impedance, inductance, and / or resistance of the at least one coil.

14. The comminution apparatus according to any one of the preceding claims, wherein at least one blade of the screw comprises a portion comprising high chrome white iron.

15. A sensor for a comminution apparatus, comprising:a sensor positionable external to a comminution chamber of the comminution device adjacent to or integrated within at least one wall of the comminution device defining the comminution chamber, the sensor configured to detect and / or monitor wear of a rotatable screw positioned within the comminution chamber.

16. The sensor of claim 15, comprising: at least one coil positioned in a housing that includes a non-ferromagnetic portion of the housing between the at least one coil and the comminution chamber.

17. The sensor of claim 15 or 16, comprising: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal that corresponds to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw.

18. The sensor according to any one of claims 15 or 16, comprising: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle which does not substantially correspond to an angle at which at least one blade of the screw is angled relative to horizontal as the at least one blade extends along a vertical shaft of the screw.

19. The sensor according to any one of the preceding claims, wherein the first sensor comprises:at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal which is not equal to 0°.

20. The sensor according to any one of claims 15-19, comprising: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal, the angle being between 5° and 60°.

21. The sensor according to any one of claims 15-20, comprising: at least one coil comprising a first coil positioned such that a longest axis of the first coil extends at an angle relative to horizontal, the angle being between 5° and 45°.

22. The sensor according to any one of claims 15-21, comprising: at least one coil comprising multiple runs of insulated metal wire to define an annular shaped multi-layer coil.

23. The sensor according to claim 22, wherein the annular shaped multi-layer coil comprises an air core or a magnetic core.

24. The sensor according to any one of claims 15-23, comprising: a portion of a housing that is a non-ferromagnetic and / or non-conductive between the at least one coil positioned in the housing and the comminution chamber.

25. The sensor according to any one of claims 15-24, comprising a thin ferromagnetic, conductive, or metallic portion between the at least one sensor and the comminution chamber.

26. A process for detecting wear of at least one component of a comminution device, the process comprising: monitoring a thickness of the distal screw edge and / or a distance between a distal edge of a screw within a comminution chamber of the comminution device and a wall of the comminution device that defines the comminution chamber; in response to detecting that an effect of the distance and / or thickness is at or beyond a pre-selected threshold, scheduling maintenance work to address wear experienced by the screw.

27. The process of claim 26, wherein the monitoring of the wear is performed by a sensor positioned external to the comminution chamber.

28. The process of claim 26 or 27, wherein the sensor is the sensor of claim 10.

29. The process of any one of claims 26-28, wherein the monitoring comprises: monitoring over time an electrical impedance, inductance and / or resistance of at least one coil of a sensor to determine a change in the distance and / or the thickness; and analyzing a time-series of monitored electrical values in combination with a known or measured rotation speed of the screw to determine how the screw has experienced wear based on the electrical values.

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