High-pressure grinding roller machine for grinding materials

Abstract

This invention relates to a high-pressure grinding roller machine for grinding materials. These machines have rollers with columns. To monitor the condition of the columns during operation of such a machine to detect wear, breakage, missing, and / or fracture of the columns, a radar system (44a) is provided on a linear drive (46a). The radar system (44a) is arranged to emit a radar beam onto the outermost surface of the roller (14) and generate a radar system output indicating the distance between the radar system and the outermost surface of the roller. The HPGR machine also includes a monitoring system comprising a processing unit connected to the radar system and configured to analyze the radar system output and determine the condition of the outermost surface of the roller.

Description

Technical Field

[0001] This disclosure relates to a high-pressure grinding roller with radar monitoring. Background Technology

[0002] High-pressure grinding rolls (HPGRs) are used in the mining and mineral processing industries to crush rocks and minerals. HPGRs use two parallel cylinders (rollers) spaced apart to form a gap between their outer surfaces. As the cylinders rotate in opposite directions, the material to be ground or crushed is fed into the gap. The material in the gap is crushed by the pressure between the two rollers.

[0003] In some HPGR designs, multiple studs are formed on the outer surface of one or two rollers. These studs are typically made of a material harder than the cylinder. The studs aid in grinding rocks. They also help form a self-generated layer of abrasive material that adheres to the cylinder surface between the studs. This self-generated layer protects the cylinder surface from wear. If a stud breaks from its mounting position on the cylinder, it can cause substantial damage to the cylinder surface, given its hardness. Monitoring the condition of the studs during HPGR operation is essential to detect stud wear, stud breakage, stud loss, and / or stud fracture. Utility Model Content

[0004] This invention is further defined herein as follows. Preferred embodiments are also described herein.

[0005] Therefore, the high-pressure grinding roller machine (HPGR machine) for abrasive materials, as claimed and described herein, includes a first roller and a second roller, each roller having a longitudinal axis of rotation and a cylindrical outer surface. The first roller and the second roller are arranged such that their longitudinal axes are parallel and a gap is formed between the outer surfaces of the rollers. The high-pressure grinding roller machine also includes a plurality of first columns. The plurality of first columns are mounted on the outer surface of the first roller and extend radially outward from the outer surface of the first roller. A first radar system is also provided, which is arranged to emit a radar beam onto the outermost surface of the first roller and generate a first radar system output indicating the distance between the radar system and the outermost surface of the first roller. The outermost surface of the first roller includes one or more of the following: the outer surface of the first roller, the plurality of columns, and a self-grown layer of broken material adhered to the outer surface of the roller. The high-pressure grinding roller machine also includes a monitoring system, which includes a processing device connected to the radar system and configured to analyze the first radar system output and determine the condition of the outermost surface of the first roller.

[0006] In a high-pressure grinding roller machine, the first radar system is preferably a synthetic aperture radar.

[0007] According to the claimed high-pressure grinding roller machine, the radar system can be mounted on a linear drive, which is arranged to move the radar system along an axis parallel to the longitudinal axis of rotation of the first roller. The range of movement preferably allows the first radar system to scan the entire axial length of the first roller. More preferably, the monitoring system is configured to use position information from the linear drive in determining the condition of the outermost surface of the first roller.

[0008] In an arrangement with a linear drive, or in another arrangement that allows the entire axial length of the first roller to be captured, the high-pressure grinding roller machine may also include a first speed sensor for determining the rotational speed of the first roller. The first speed sensor is then communicatively connected to a monitoring system. If the monitoring system is configured to use speed data from the first speed sensor to calibrate data received from a first radar system and from the linear drive, a height map of the outermost surface of the roller can be generated.

[0009] According to the high-pressure grinding roller machine for which protection is sought, the processing device is configured to have a first operating mode and a second operating mode.

[0010] The first operating mode is preferably a continuous scanning mode, wherein the current distance measured between the first radar system and a given position on the outermost surface of the roller is compared with a previously measured distance between the first radar system and the given position measured during a previous rotation of the roller. More preferably, the monitoring system is configured to output an alarm when the difference between the current distance and the previously measured distance exceeds a predetermined amount, the alarm indicating the position on the roller corresponding to the given position. The predetermined amount may be about 2 mm, but can be greater than or less than 2 mm.

[0011] The second operating mode is preferably a wear measurement mode performed when the roller is rotating and there is no abrasive material in the gap. Then, more preferably, the processing device is first configured to identify the distance from the first radar system to each of the plurality of columns, and determine the height of each column above the outer surface of the roller with an accuracy greater than 0.5 mm, and then compare the determined height of each column with the expected height obtained from the column in the new condition. This allows the wear condition of each column to be calculated based on the difference between the determined height and the expected height. Still more preferably, the processing device is then configured to identify a group of worn columns and output the position of each of the worn columns in the group on the outer surface of the roller. In the context of this disclosure, worn columns are understood to be columns with a wear condition below a predetermined threshold.

[0012] The high-pressure grinding roller machine claimed and described herein may also include a second radar system arranged to monitor a plurality of second columns on the outer surface of the second roller. If so, the second radar system will preferably be configured to generate a second radar system output to the monitoring system. This second radar system output may, for example, indicate the distance between the second radar system and the outermost surface of the second roller.

[0013] The high-pressure grinding roller machine claimed and described herein may also include a housing and a skew control mechanism to keep the rollers at a desired distance, and preferably also at a distance and angle relative to each other.

[0014] The skew mechanism acts on at least one longitudinal axis of the roller, preferably on one longitudinal axis of the roller. In this preferred embodiment, the first roller is fixed relative to the housing, and the second roller is movable relative to the housing, such that the size of the gap between the surfaces of the rollers varies. The second roller is then operatively connected to a skew control mechanism, which is configured to control the movement of the longitudinal axis of the second roller, thereby controlling the size of the gap. Alternatively, the longitudinal axis of the second roller can be fixed relative to the housing, and the longitudinal axis of the first roller can be movable relative to the housing, such that the size of the gap varies. The first roller is then operatively connected to a skew control mechanism, which is configured to control the movement of the longitudinal axis of the first roller, thereby controlling the size of the gap. In any of these alternatives, the skew control mechanism can also be configured to keep the longitudinal axes of the rollers parallel to each other. Attached Figure Description

[0015] Figure 1 The HPGR machine is shown;

[0016] Figure 2 A perspective view of two rollers of the HPGR machine is shown;

[0017] Figure 3 A perspective view of two rollers inside the HPGR machine is shown;

[0018] Figure 4 The cross-sections of the two rollers are shown;

[0019] Figure 5 and Figure 6 Each depicted a roller;

[0020] Figure 7 A monitoring system for monitoring rollers is shown;

[0021] Figure 8 and Figure 9 A radar system and linear drive for monitoring the rollers are shown;

[0022] Figure 10 The linear driver and linear drive controller are described;

[0023] Figure 11 The radar unit is shown;

[0024] Figures 12-14 The radar system is shown, and each radar system includes two radar units;

[0025] Figure 15 A linear driver is shown;

[0026] Figure 16 It is a height map of the outermost surface of the roller measured using a radar system;

[0027] Figure 17A A portion of a roller with columns and some self-generating layers is shown;

[0028] Figure 17B It is by Figure 17A The height map is determined by radar data for the roller section shown.

[0029] Figure 18A The text depicts a worn column;

[0030] Figure 18B It is by Figure 18A The height map determined by radar data of the worn column;

[0031] Figure 19 It is another height map determined by radar data from the outermost surface of the roller;

[0032] Figure 20 It is another height map that includes monitoring of one or more end plates of the rollers;

[0033] Figure 21 It is another monitoring system for the monitoring roller;

[0034] Figure 22 Three height maps generated using different compensation methods are shown to compensate for variable roll speeds during rotation; and

[0035] Figure 23 The speed sensor and the metal part it detects during roller rotation are shown.

[0036] List of reference numerals

[0037] HPGR 10

[0038] Hopper 12

[0039] First roller 14

[0040] First roller rotation axis 14a

[0041] First roller rotation direction 14b

[0042] Cleaning area (outer surface of the roller) 14c

[0043] Second roller 16

[0044] Second roller rotation axis 16a

[0045] Second roller rotation direction 16b

[0046] Gap 18

[0047] Drive motors 20 and 22

[0048] skew control system 24

[0049] End plate 26

[0050] Column 28

[0051] Self-generating layer 30

[0052] Monitoring System 40

[0053] First speed sensor 42a

[0054] Second speed sensor 42b

[0055] First Radar System 44a

[0056] Second radar system 44b

[0057] Metal parts 45

[0058] First linear driver 46a

[0059] Second linear driver 46b

[0060] First linear drive controller 47a

[0061] Second linear drive controller 47b

[0062] Control Unit 48

[0063] Computer 49

[0064] Radar Unit 50a

[0065] RF board 52

[0066] Plano-convex lens 54 Detailed Implementation

[0067] Figure 1 A high-pressure grinding roller (HPGR) 10 machine is shown. The HPGR 10 includes components mounted on... Figure 2 , Figure 3 and Figure 4 The image depicts a hopper 12 (or chute) above two rollers 14 and 16. Each roller 14 and 16 has a corresponding axis of rotation 14a and 16a. The rollers 14 and 16 are arranged such that their axes of rotation 14a and 16a are parallel to each other. In this arrangement, a gap 18 is formed between the two rollers 14 and 16. The gap 18 is defined herein as the narrowest point between the two rollers 14 and 16. Brief Reference Figure 4 During operation, the material to be crushed is fed from the top side of rollers 14 and 16 (i.e., from hopper 12) in the direction marked by arrow R. The material may briefly reside in the area defined between the uppermost vertical portion of the roller and the gap. Rollers 14 and 16 rotate in the direction indicated by curved arrows 14b and 16b, such that at gap 18, the outer surface of each of rollers 14 and 16 moves downward. This movement draws the material located in the aforementioned area into gap 18 for crushing.

[0068] Each of rollers 14 and 16 is rotated by a corresponding drive motor 20 or 22. Figure 1 The first roller 14 of the two rollers is mounted such that its axis of rotation 14a is fixed relative to the ground and relative to the hopper 12. The second roller 16 of the two rollers is mounted such that its axis of rotation 16a is floating, making the linear distance between the two axes 14a, 16a variable. A skew control system 24 is provided. In this embodiment, the skew control system is mechanical. The skew control system supports the second roller 16 to allow the second roller to float (i.e., allow the linear distance to change), while also keeping the two axes 14a, 16a parallel to each other. Therefore, the size of the gap 18 varies within limits determined by the skew control system 24.

[0069] The two rollers 14 and 16 have substantially equal lengths. The two rollers 14 and 16 are arranged such that the first end of the first roller 14 is axially aligned with the first end of the second roller 16, and the second end of the first roller 14 is axially aligned with the second end of the second roller 16.

[0070] Typical roller lengths range from 250 mm to 2000 mm. Typical diameters range from 800 mm to 4000 mm.

[0071] Each roller may be provided with one or more end plates 26 to ensure that material from the hopper 12 enters the gap 18 and does not fall from one axial end of the rollers 14, 16. Typically, there will be two sets of one or more end plates, one set positioned adjacent to a first end of the roller and the other set positioned adjacent to a second end of the roller. One or more end plates 26 on a roller (e.g., the first roller 14) describe an annular or circular profile with a radius larger than that of the first roller 14. The radius of this profile is equal to or greater than the sum of the radius of the first roller and the maximum dimension of the gap 18. This ensures that one or more end plates 26 on the first roller 14 overlap with the second roller 16. This overlap prevents material from falling from the axial end of the gap 18 or from the axial end of the roller above the gap 18. In some examples, a roller has an end plate 26 at either axial end. In other examples, a roller has an axial plate at one axial end and another roller has an axial plate at the other axial end.

[0072] In some examples, the roller is provided with a single axial end plate that describes the entire ring. However, since the diameter of the roller in the HPGR can be several meters, the integral end plate must also have a diameter of several meters. Such a large integral end plate can be difficult to construct, install, maintain, and / or replace. Therefore, in other examples, multiple end plates 26 can be provided, each end plate describing a segment of the entire ring, such that each end plate 26 can be constructed, installed, and / or replaced separately from the other end plates 26 forming the ring.

[0073] Figure 5 and Figure 6 This is a depiction of the first roller 14 in HPGR 10. The roller shown is part of the machine used as a test model. Based on the principles of dimensional analysis, the test model was designed to be smaller than a full-size HPGR that can have a roller diameter of several meters. Apart from this change in diameter, the operation of the test model is the same as that of the full-size HPGR.

[0074] Figure 5 A first roller 14 is shown having a plurality of columns 28 mounted on its outer surface. The first roller 14 has an end plate 26 at any axial end of the roller 14. Figure 6 The first roller 14 after use (with end plates 26 removed) is shown, where a self-grown layer 30 has been formed between the columns 28. The self-grown layer 30 is formed from broken material that accumulates between the columns 28 during operation. Due to pressure from the broken material, the self-grown layer 30 is compacted onto the outer surface of the roller 14.

[0075] Figure 6 The worn column 28w is also shown. Column 28 is made of a hard material such as tungsten carbide. This material of column 28 is typically harder than the material of the outer surface of rollers 14, 16.

[0076] Column 28 is a replaceable component and can be replaced when a given column 28 is excessively worn or when it breaks. Because column 28 is made of a material harder than the outer surfaces of rollers 14 and 16, a broken column pulled into gap 18 can cause substantial damage to the outer surfaces of rollers 14 and 16. Therefore, it is desirable to monitor the condition of column 28 during operation of the HPGR 10.

[0077] Figure 7 An HPGR 10 with a monitoring system 40 is schematically depicted. In some examples, the monitoring system 40 may monitor only one roller of the HPGR 10. In other examples, the monitoring system may monitor both rollers of the HPGR 10.

[0078] The main components of the monitoring system 40 will now be described in relation to monitoring one roller (first roller 14) of the HPGR 10. However, this description also applies to the monitoring of the second roller 16 or both rollers. The monitoring system includes a first speed sensor 42a for monitoring the rotational speed of the first roller 14. The speed sensor 42a may be located at or beyond the axial end of the first roller 14. For example, the speed sensor 42a may monitor the rotational speed of the shaft of the first roller 14, and this may be converted into the rotational speed of the outer surface of the roller 14. For example, the shaft may have a plurality of metal pieces (optionally, magnetic metal pieces) spaced at equal angles around its circumference, and the speed sensor may include an inductive sensor fixed in a position such that each metal piece passes through the inductive sensor in sequence as the roller 14 rotates. The passage of each metal piece is detected by the inductive sensor as a pulse. The timing between pulses and / or the width of the pulses may be converted into the rotational speed of the roller 14. A metal piece may have a central gap, such that it rapidly and continuously generates two signals in the inductive sensor. Unlike signals generated by other metal parts, this signal allows for confirmation that the roller has completed its full rotation.

[0079] The monitoring system 40 also includes a first radar system 44a mounted to the first linear drive 46a. The first radar system 44a and the first linear drive 46a are communicatively connected to the control unit 48. A first speed sensor 42a is also communicatively connected to the control unit 48. In this example, the first linear drive 46a is controlled by a first linear drive controller 47a, which is communicatively connected to the control unit 48. The first linear drive controller 47a can transmit the position of the linear drive to the control unit 48, which provides the position of the radar system 44a relative to the rotation axis 14a of the roller 14.

[0080] The control unit 48 can be communicatively connected (e.g., via a wired or wireless connection) to a computer 49, such as a laptop or PC.

[0081] The first radar system 44a is arranged on the side of roller 14 that is substantially opposite to gap 18. This ensures that the first radar system 44a is spaced apart from any material (rock, mineral, etc.) from hopper 12 to gap 18, and also from any material below gap 18 on the underside of rollers 14, 16. Figure 7 In the schematic diagram shown, if the position of the narrowest part of the gap defines the 0° position of the first roller 14, then the first radar system is spaced from the gap by an angle equal to or greater than 90° and equal to or less than 270° along the counterclockwise circumferential direction of the first roller 14. Figure 7 As shown. This position facilitates the mounting of the radar system 44a onto the monitoring system 40. In this arrangement, material from the hopper 12 will contact the first roller 14 between the 0° position and the <90° position (i.e., the uppermost vertical portion of the first roller 14).

[0082] As described below, a second radar unit 44b can be provided. Figure 7 In the schematic diagram shown, if the position of the narrowest part of the gap defines the 0° position of the second roller 16, then the second radar system 44b is spaced from the gap 18 by an angle equal to or greater than 90° and equal to or less than 270° along the clockwise circumferential direction of the second roller 16. Figure 7 As shown. This position facilitates the installation of the radar system 44b onto the monitoring system 40.

[0083] Figures 8-10 A first radar system 44a and a first linear actuator 46a are shown. The first radar system 44a is mounted to the first linear actuator 46a. The first linear actuator 46a is arranged to move the first radar system 44a linearly along an axis parallel to the rotation axis 14a of the first roller 14. The first radar system 44a includes at least one radar unit 50a pointing towards the outer surface of the roller 14 (see [link to original text]). Figures 12-14 Radar unit 50a is configured to transmit a radar beam onto the outermost surface of the roller and receive radar beams reflected from the outermost surface of the roller. The radar unit is designed to form a point on the roller 14 with the radar beam. In some examples, the point of the radar beam has a diameter between 7 mm and 13 mm on the surface defined by the outermost point of the intact and unworn column of the roller.

[0084] In operation, the outermost surface of roller 14 may consist of any one or all of the following: the outer surface of roller 14, the pillars 28, and the self-grown layer 30. That is, when roller 14 is thoroughly cleaned, for example, before first use or after refurbishment, the outermost surface detected by radar unit 50a will include the outer surface of roller 14 and the pillars 28. After a short period of use, the self-grown layer 30 may have accumulated between some, but not all, of the pillars 28, leaving some of the outer surface of the roller still exposed. In this case, the outermost surface detected by radar unit 50a will include some portions of the outer surface of roller 14, the pillars 28, and some portions with the self-grown layer 30. After further use, the self-grown layer 30 may completely cover the outer surface of the roller and may even extend just above the tops of some pillars 28 in some places. In this case, the outermost surface detected by radar unit 50a includes the self-grown layer 30 and some (or all) of the pillars 28.

[0085] The first linear actuator 46a is mounted at a fixed distance from the axis 14a of the roller 14. This means that the radar system 44a is maintained at a fixed distance from the outer surface of the roller 14 without any wear on the outer surface. This fixed distance is preferably set between 5 cm and 30 cm. The post 28 extends above the outer surface of the roller 14 such that the distance between the unworn post 28 and the radar system 44a is less than this fixed distance. The self-grown layer 30 extends above the outer surface of the roller such that the distance between the self-grown layer 30 and the radar system 44a is less than this fixed distance.

[0086] During the operation of HPGR 10, the first linear actuator 46a causes the first radar system 44a to move back and forth along the axial length of the roller 14. In some examples, the first linear actuator 46a moves the first radar system in a continuous motion. During this time, the roller 14 rotates. Therefore, the points of the radar beam describe the helical shape on the outermost surface of the roller 14. By adjusting the rotational speed of the roller 14, and particularly the back-and-forth scanning speed of the first linear actuator 46a, the radar system 46a is able to map the entire outermost surface of the roller 14.

[0087] Alternatively, the first linear actuator 46a can be configured to move the radar system 44a in a stepwise manner. For example, it can move the first radar system in fixed increments after an integer number of full rotations of the roller 14 (e.g., after one full rotation of the roller 14 or after two full rotations of the roller 14, etc.). In this case, the radar beam point will sweep across a series of axially adjacent circles on the outermost surface of the roller 14. Figure 9 In the test unit shown, the linear actuator is a Rexroth linear actuator, typically Model MKK-065-NN-3 R030544889, with a total length of 131cm and an actuator length of 75cm. This linear actuator is also... Figure 15 As shown in the image.

[0088] In some examples, the first linear actuator 46a can move the first radar system 44a in steps of 1 mm per revolution of roller 14. In other examples, it can move the first radar system 44a in steps of 2 mm. In the example roller shown, the posts 28 are arranged in a regular repeating pattern, showing rows with clearly spaced intervals, each row separated by a row distance. The first linear actuator 46a can be configured to move the first radar system 44a in steps equal to the row distance, such that the radar system obtains a measurement of the surface of each post 28 in a given row (e.g., taken from the center of each post) before moving to the next row of posts 28. Compared to measurements with closer intervals, this exemplary process may lose some fine details of the height map, but it can allow for faster generation of a map of the entire outermost surface of the roller. This process can be particularly useful when there is only interest in quickly identifying missing or shortened posts 28 across the entire roller.

[0089] Figure 11 This is a photograph of an exemplary radar unit 50a. The illustrated radar unit 50a has an FWCW radar chip mounted on an RF board 52 and a plano lens 54. The radar unit 50a can be configured to operate at a frequency of 120-140 GHz. Figure 11 The radar unit shown is a silicon radar, a 120-140 GHz radar unit, such as the Indie Semiconductor TRA_120_045. In other examples, an elliptical lens can be used instead of a plano-convex lens.

[0090] Radar system 44a may include two radar units 50a arranged adjacent to each other, and these examples are in... Figures 12-14 As shown in the diagram, the first radar unit 50a can be configured to transmit a radar beam with a first polarization (e.g., polarized along the x-direction), and the second radar unit 50a can be configured to transmit a radar beam with a second polarization orthogonal to the first polarization (e.g., polarized along the y-direction). This can overcome noise in the signal and compensate for backscattering losses. Because waves are scattered based on surface differences, cross or angled polarization can help improve the signal rx / tx quality.

[0091] The radar unit 50a, or each radar unit 50a, provides an output signal that is processed to determine the distance between the radar unit and the outermost surface of the roller 14. The output signal can be processed into a distance by the first radar system 44a or by the control unit 48. The control unit 48 is configured to combine the distance data with velocity data from the velocity sensor 42a and position data from the first linear drive 46a to determine any one or more of the following: wear of the column 28, breakage of the column (which can manifest as a significantly reduced column height or a column completely missing from its intended position on the roller), thickness of the self-grown layer 30, and wear on the outer surface of the roller 14. The control unit 48 can be configured to generate a height map of the outermost surface of the roller 14. Figure 16 An example heightmap is shown. Alternatively, the heightmap can be generated by computer 49 based on data received from control unit 48.

[0092] In the test unit, the following components are used for signal processing of the output from the radar unit: a processor demo board (Zynq ZC702) and an ADC demo board (AD7606CFMC), as well as a custom adapter board. MATLAB is used to process the data into a height map.

[0093] The first radar system 44a can operate as a synthetic aperture radar.

[0094] exist Figure 16 In the upper part of the height map, column 28 is clearly visible as a blue circle. The map was calibrated so that when the radar system detects a distance equal to a fixed distance (which is the outer surface of roller 14), the map appears white. In the height map, some areas of the authigenic layer 30 are also visible as speckle patterns between columns 28.

[0095] Figure 16 The height map in the lower part is Figure 16 3D pseudo-color rendering of the upper part of the height map.

[0096] Figure 17A A photograph of a portion of the roller is shown, in which the columns 28 and some self-grown layers 30 are visible, and in which there are clean areas 14c between the four columns, making the outer surface of the roller 14 visible. Figure 17B It shows from such Figure 17A The 3D height map defines the same portion of the roller shown. Figure 17B In the diagram, the four pillars appear to be clearly defined above the outer surface of the roller (i.e., relative to the clean area 14c, which is the exposed outer surface of the roller 14). Other areas of the heightmap show varying amounts of self-grown layers 30 between the other pillars 28.

[0097] Figure 18A A photograph of the shattered column 28 is shown. Figure 18BThe elevation map of the same fractured column 28 is shown. This was determined from radar data. Figure 18B The uneven upper surface of column 28 can be clearly identified in the height map.

[0098] Figure 19 A height diagram of another portion of roller 14 is shown, in which multiple columns 28 are clearly visible, as are the cleaned area 14c of the outer surface of roller 14 and some areas with self-grown layers 30.

[0099] Figure 20 Another height diagram of the outermost surface of the roller is shown. In this case, the roller has one or more end plates 26 at one axial end. These are shown in the figure as follows. Figure 20 A continuous horizontal blue line at the top. Therefore, the radar system can also monitor one or more endplates 26, for example, to detect wear or damage to one or more endplates 26.

[0100] Figure 21 An alternative arrangement is shown in which there is no separate linear drive controller 47a; instead, the first linear drive 46a is directly connected to the control unit 48, and the control unit 48 is configured to control the first linear drive 46a. All other features of this alternative arrangement are consistent with those described above. Figures 1-19 The layouts described are the same.

[0101] The first linear actuator 46a preferably has a length that surrounds the entire axial length of each roller, allowing the radar system 44a to move to scan the entire outermost surface of the roller 14. The first linear actuator 46a may also preferably have a length that further surrounds any end plates 26 of the roller (if present, they may be located only at one end of the roller or at both ends), allowing the first radar system 44a to additionally scan the end plates 26. In addition to monitoring the outermost surface of the roller 14, this also allows the control unit 48 to additionally monitor wear or damage on one or more end plates 26.

[0102] The monitoring system 40 has already been described above for monitoring one roller (first roller 14). In some instances, the monitoring system 40 can be configured to monitor only the second roller 16 or both the first roller 14 and the second roller 16. In the case of monitoring both rollers 14, 16, a second radar system 44b is provided, mounted on a second linear drive 46b. A second speed sensor 42b is provided, which is arranged to measure the rotational speed of the second roller 16. The second linear drive 46b is mounted at a second fixed distance from the outer surface of the second roller 16, which may be the same as or different from the first fixed distance. The second linear drive 46b is arranged to move the second radar system 44b along an axis parallel to the rotational axis of the second roller 16. In use, the second linear drive 46b causes the second radar system 44b to scan back and forth across the axial length of the second roller 16. The second radar system 44b outputs distance data to the control unit 48 in the same manner as described above for the first radar system 44a. Therefore, in this example, the control unit 48 can monitor both rollers 14, 16 simultaneously. Furthermore, the control unit 48 can be communicatively connected to an external computer 49 (laptop, PC, etc.), and the height map can be graphically generated solely by the computer 49.

[0103] As described above, the second speed sensor 42b may have the same construction as the first speed sensor 42a. As described above, the second radar system 44b may have the same construction as the first radar unit 44a. As described above, the second linear actuator 46b may have the same structure as the first linear actuator 46a. As described above, the second linear drive controller 47b may have the same structure as the first linear drive controller 47a.

[0104] During the operation of the HPGR 10, a large amount of airborne dust is generated from the crushed material. Radar (especially radar in the frequency range of 120-350 GHz, or more preferably 120-140 GHz or 250-300 GHz) can penetrate the airborne dust and reliably measure the distance to the outermost surface of the roller. This contrasts with existing monitoring schemes that use visible light, which is easily scattered by airborne dust, potentially making accurate measurements difficult.

[0105] In one test, while the radar system 44a remained stationary, the roller 14 rotated multiple times, allowing the repeatability of the measurement to be determined by scanning the same set of columns multiple times. The radar system was found to have repeatability on the order of 0.01 mm. That is, multiple measurements of the same column height taken over multiple rotations of the roller yielded results on the order of 0.01 mm. The pure range measurement accuracy of the broadband millimeter-wave FMCW radar is approximately on the order of tens of micrometers.

[0106] During operation, the two rollers 14 and 16 experience vibration due to the significant forces involved in crushing materials such as rocks and minerals. Therefore, preferably, the linear drive is firmly mounted relative to the axis of rotation of the rollers (whether it is a fixed roller or a movable / floating roller) such that any movement of the axis of rotation also causes movement of the linear drive, so that the relative position of the rollers and the linear drive is as fixed as possible.

[0107] During operation, for example, the rotational speed of the roller can vary due to changes in the material being broken at any given moment. Therefore, it is preferable to accurately measure the instantaneous rotational speed of the roller and use this data when generating the height map. This allows for precise determination of the intervals between different radar measurements. In one example, the speed sensor is configured to perform four speed measurements per revolution of the roller. This is achieved by providing four metal pieces on the roller's shaft, spaced at equal angles (i.e., 90 degrees apart in this example), for detection by the induction-based speed sensor. It has been found that this provides sufficiently accurate speed information of the roller during use, where the roller exhibits some variation in rotational speed with each revolution, allowing for accurate generation of the height map.

[0108] Figure 22 A comparison of height maps generated using different methods for determining the roller rotation speed is shown. Height map A is generated without using a compensation algorithm, i.e., assuming a constant roller rotation speed. Height map B is generated using a compensation algorithm that uses data from a speed sensor that detects a single point on the roller (i.e., a single metal piece), i.e., a single roller speed measurement during each complete rotation. Height map C is generated using a compensation algorithm that uses data from a speed sensor that detects four equidistant points on the roller (i.e., four metal pieces), i.e., four roller speed measurements during each complete rotation. Comparing the three maps shows that the true circular outline of column 28 appears clearer in Figure C compared to Figures A and B. This indicates that four speed measurements per rotation provide a reasonable height map.

[0109] Figure 23 The image shows a speed sensor 44a and the aforementioned metal piece 45 with a central notch. This metal piece allows the speed sensor 44a to detect two closely spaced peaks, which enables easy determination that the specific metal piece is passing through the sensor. This indicates a complete rotation of the roller, since there is only one metal piece with a central notch on the roller shaft.

[0110] An alarm system can be implemented in monitoring system 40. The alarm system can be generated in control unit 48 or computer 49, or both. The control unit (or computer) is configured to continuously monitor any characteristic changes exceeding 1 mm (in any direction) between consecutive scans of the same portion of the roll. For example, a change >2 mm can indicate that a given column 28 has broken or fractured off the roll. The alarm system can identify the point of failure associated with the actual roll surface. That is, the alarm can not only indicate that one or more columns have broken or fractured, but also identify which specific column(s) have broken or fractured, enabling technicians to quickly locate and replace the damaged column on the actual roll. Although this is not preferred, the alarm system can optionally output an emergency stop signal to stop the rotation of rolls 14, 16 when a broken column is detected.

[0111] The monitoring system 40 can be configured to have a wear measurement mode, which is performed when the HPGR machine is running (i.e., the rollers are rotating) but not abrading the material. In this mode, the amount of wear on the outer surfaces of the posts 28 and the rollers can be measured with an accuracy varying in the height direction of 0.1 mm. Posts with wear exceeding a predetermined amount (e.g., exceeding 1 mm) can be identified by the monitoring system 40, and their positions on the actual roller surface can be indicated. This allows technicians to quickly locate worn posts on the actual roller surface and replace them during maintenance intervals.

Claims

1. A high pressure grinding roller machine for grinding material, characterized in that, include: The first roller has a longitudinal axis of rotation and a cylindrical outer surface. A plurality of first posts are mounted on the outer surface of the first roller and extend radially outward from the outer surface of the first roller; The second roller has a longitudinal axis of rotation and a cylindrical outer surface. The first roller and the second roller are arranged such that their longitudinal axes are parallel to form a gap between the outer surfaces of the first roller and the second roller; A first radar system is arranged to emit a radar beam onto the outermost surface of the first roller and generate a first radar system output, the first radar system output indicating the distance between the first radar system and the outermost surface of the first roller. The outermost surface of the first roller includes one or more of the following: the outer surface of the first roller, the plurality of first columns, and a self-generated layer of broken material adhered to the outer surface of the first roller; the machine further includes: The monitoring system includes a processing unit connected to the first radar system and configured to analyze the output of the first radar system and determine the condition of the outermost surface of the first roller.

2. The high-pressure grinding roller machine according to claim 1, characterized in that, The first radar system is a synthetic aperture radar.

3. The high-pressure grinding roller machine according to claim 1, characterized in that, The first radar system is mounted on a linear drive, wherein the linear drive is arranged to move the first radar system along an axis parallel to the longitudinal axis of rotation of the first roller, allowing the first radar system to scan the entire axial length of the first roller, wherein the monitoring system is configured to use position information from the linear drive in determining the condition of the outermost surface of the first roller.

4. The high-pressure grinding roller machine according to claim 3, characterized in that, It also includes a first speed sensor for determining the rotational speed of the first roller, the first speed sensor being communicatively connected to the monitoring system; wherein the monitoring system is configured to use speed data from the first speed sensor to calibrate data received from the first radar system and from the linear drive to form a height map of the outermost surface of the first roller.

5. The high-pressure grinding roller machine according to any one of claims 1 to 4, characterized in that, The processing device is configured to have a first operating mode and a second operating mode.

6. The high-pressure grinding roller machine according to claim 5, characterized in that, The first operating mode is a continuous scanning mode, wherein a current distance measured between the first radar system and a given position on the outermost surface of the first roller is compared with a previously measured distance between the first radar system and the given position measured during a previous rotation of the first roller, and wherein the monitoring system is configured to output an alarm when the difference between the current distance and the previously measured distance exceeds a predetermined amount, the alarm indicating a position on the first roller corresponding to the given position, optionally wherein the predetermined amount is 2 mm.

7. The high-pressure grinding roller machine according to claim 5, characterized in that, The second operating mode is a wear measurement mode performed when the first roller and the second roller are rotating and there is no abrasive material in the gap, wherein the processing device is configured to identify the distance from the first radar system to each of the plurality of first columns and determine the height of each column above the outer surface of the roller with an accuracy greater than 0.5 mm; wherein the processing device is further configured to compare the determined height of each column with an expected height obtained from the column in the new condition, and calculate the wear condition of each column based on the difference between the determined height and the expected height.

8. The high-pressure grinding roller machine according to claim 7, characterized in that, The processing device is configured to identify a set of worn columns, the set of worn columns being columns whose wear condition is below a predetermined threshold, and to output the position of each column in the set of worn columns on the outer surface of the roller.

9. The high-pressure grinding roller machine according to any one of claims 1 to 4, characterized in that, It also includes a second radar system, which is arranged to monitor a plurality of second columns on the outer surface of the second roller and is configured to generate a second radar system output to the monitoring system, wherein the second radar system output indicates the distance between the second radar system and the outermost surface of the second roller.

10. The high-pressure grinding roller machine according to any one of claims 1 to 4, characterized in that, The high-pressure grinding roller machine includes a housing and a skew control mechanism.

11. The high-pressure grinding roller machine according to claim 10, characterized in that, The longitudinal axis of the first roller is fixed relative to the housing, and the longitudinal axis of the second roller is movable relative to the housing such that the size of the gap is variable, wherein the second roller is operatively connected to the skew control mechanism, wherein the skew control mechanism is configured to control the movement of the longitudinal axis of the second roller, thereby controlling the size of the gap.

12. The high-pressure grinding roller machine according to claim 10, characterized in that, The longitudinal axis of the second roller is fixed relative to the housing, and the longitudinal axis of the first roller is movable relative to the housing such that the size of the gap is variable, wherein the first roller is operatively connected to the skew control mechanism, wherein the skew control mechanism is configured to control the movement of the longitudinal axis of the first roller, thereby controlling the size of the gap.

13. The high-pressure grinding roller machine according to claim 10, characterized in that, The skew control mechanism is also configured to keep the longitudinal axes of the rollers parallel to each other.

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