Magnet separator and magnetic sludge removing method

Abstract

To provide a magnet separator configured such that reduction of recovery performance of a magnetic sludge or a failure of a device is difficult to occur even when a content of a magnetic sludge in liquid to be treated increases.SOLUTION: An outer circumferential surface of a magnetic drum is partially immersed in a flow of magnetic sludge-containing liquid to be treated. A removing mechanism removes a magnetic sludge on the outer circumferential surface of the magnetic drum from the outer circumferential surface of the magnetic drum. A magnetic sludge-containing information acquisition device acquires magnetic sludge-containing information regarding a content of a magnetic sludge contained in the liquid. A control device changes magnetic sludge removing performance of the magnetic drum in accordance with the sludge-containing information acquired by the magnetic sludge-containing information acquisition device. A circumferential velocity of the magnetic drum is opposite to a flowing direction of the liquid to be treated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic separator, a magnetic separator control device, and a magnetic sludge removal method. [Background technology]

[0002] A magnetic separator is known as a device for removing magnetic sludge from a liquid to be treated that contains magnetic sludge (Patent Document 1, Patent Document 2). In a magnetic separator, a rotating magnetic drum is partially immersed in the liquid to be treated, and the magnetic sludge in the liquid to be treated is attracted to the outer peripheral surface of the magnetic drum by magnetic force. The magnetic sludge attracted to the outer peripheral surface is separated from the liquid to be treated as the magnetic drum rotates. After being separated from the liquid to be treated, the magnetic sludge attracted to the outer peripheral surface of the magnetic drum is scraped off the outer peripheral surface of the magnetic drum by a scraper or the like, and discharged to the outside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-1176 [Patent Document 2] JP 2018-89560 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the content of magnetic sludge contained in the liquid to be treated increases, the magnetic sludge recovery performance may decrease and equipment malfunctions may occur due to the adsorption of a large amount of magnetic sludge to the magnetic drum. An object of the present invention is to provide a magnetic separator that is less likely to cause a decrease in magnetic sludge recovery performance or equipment malfunctions even if the content of magnetic sludge in the liquid to be treated increases or decreases. Another object of the present invention relates to a magnetic separator control device that controls this magnetic separator. Yet another object of the present invention is to provide a magnetic sludge removal method that is less likely to cause a decrease in magnetic sludge recovery performance or equipment malfunctions even if the content of magnetic sludge in the liquid to be treated increases or decreases. [Means for solving the problem]

[0005] According to one aspect of the present invention, a magnetic drum having a part of its outer circumferential surface immersed in a flow of the liquid to be treated containing magnetic sludge and rotating while generating a magnetic force on the outer circumferential surface; a removing mechanism for removing magnetic sludge on the outer peripheral surface of the magnet drum from the outer peripheral surface of the magnet drum; a magnetic sludge content information acquiring device for acquiring magnetic sludge content information relating to the amount of magnetic sludge contained in the liquid to be treated; a control device that changes the magnetic sludge removal capacity of the magnet drum in accordance with the magnetic sludge content information acquired by the magnetic sludge content information acquisition device; A magnetic separator having a magnetic separator is provided.

[0006] According to another aspect of the invention, Acquire magnetic sludge content information relating to the content of magnetic sludge contained in the liquid to be treated flowing into the magnetic separator; A magnetic separator control device is provided which changes the magnetic sludge removal capacity of the magnetic separator in accordance with the acquired magnetic sludge content information.

[0007] According to yet another aspect of the present invention, Acquire magnetic sludge content information relating to the content of magnetic sludge contained in the liquid to be treated flowing into the magnetic separator; There is provided a magnetic sludge removal method in which the magnetic sludge removal capacity of the magnetic separator is changed according to the acquired magnetic sludge content information. Effect of the Invention

[0008] By changing the magnetic sludge removal capacity of the magnetic drum in accordance with the magnetic sludge content information, it is possible to suppress a decrease in the magnetic sludge recovery performance. By increasing the removal capacity in accordance with an increase in the magnetic sludge content, the occurrence of equipment malfunctions due to the adhesion of a large amount of magnetic sludge to the magnetic drum becomes less likely. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a magnetic separator according to an embodiment. [Diagram 2] FIG. 2 is a graph showing an example of the relationship between the measured value of the magnetic sludge content and the target value of the rotation speed of the magnet drum. [Diagram 3] FIG. 3 is a graph showing the change over time in the target value of the rotation speed of the magnet drum during the period when the measured value of the magnetic sludge content is below the reference lower limit. [Figure 4] FIG. 4 is a schematic diagram of a grinding system according to another embodiment. [Diagram 5] FIG. 5 is a schematic diagram of a grinding system according to yet another embodiment. [Figure 6] FIG. 6 is a schematic diagram of a magnetic separator and a grinding device according to still another embodiment. [Figure 7] FIG. 7 is a graph showing the relationship between the measured value of the magnetic sludge content in the coolant and the target value of the flow rate of the coolant. [Figure 8] FIG. 8 is a schematic diagram of a magnetic separator and a grinding device according to still another embodiment. [Figure 9]FIG. 9 is a graph showing an example of the relationship between the grinding conditions and the target value of the rotation speed of the magnet drum. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A magnetic separator according to an embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic diagram of a magnetic separator according to an embodiment. A flow path 32 is defined in a housing 10, through which a liquid to be treated 30 containing magnetic sludge 31 flows. The housing 10 has an inlet 11 through which the liquid to be treated 30 flows, and an outlet 12 through which the liquid to be treated 30 is discharged. A magnetic drum 20 is disposed in the housing 10. When the liquid to be treated 30 reaches the downstream end of the flow path 32, it is discharged from the outlet 12 to the outside.

[0011] The magnet drum 20 is supported in the housing 10 with its central axis parallel to the liquid surface of the liquid 30 to be treated and perpendicular to the direction of flow of the liquid 30 to be treated. The magnet drum 20 has an outer cylinder 21 and an inner cylinder 22. A portion of the outer peripheral surface of the outer cylinder 21 in the circumferential direction, for example, approximately half the circumference of the lower side, is immersed in the liquid 30 to be treated. The outer cylinder 21 is rotated by a motor 25 about the central axis. The driving force from the motor 25 to the outer cylinder 21 is transmitted by, for example, a sprocket and a chain. The movement direction (circumferential speed direction) of the outer peripheral surface of the outer cylinder 21 is opposite to the flow direction of the liquid 30 to be treated.

[0012] The inner cylinder 22 is fixed to the housing 10 and does not rotate, and a plurality of magnets 23 are arranged in a line in the circumferential direction on the outer circumferential surface of the inner cylinder 22. Each of the magnets 23 is arranged so that magnetic poles of mutually different polarities appear on the inner and outer circumferential surfaces, and S poles and N poles appear alternately in the circumferential direction. The magnets 23 are also arranged in the circumferential direction in a region immersed in the liquid 30 to be treated and in a region extending from the immersed region to the top of the inner cylinder 22 in the circumferential direction of the outer circumferential surface of the outer cylinder 21. The plurality of magnets 23 generate a magnetic flux on the outer circumferential surface of the outer cylinder 21. The magnetic flux attracts the magnetic sludge 31 to the outer circumferential surface of the outer cylinder 21.

[0013] A part of the bottom surface of the flow path 32 for the liquid to be treated 30 is shaped to reflect the shape of the outer circumferential surface of the outer cylinder 21 so that the radial dimension from the outer circumferential surface of the outer cylinder 21 to the bottom surface of the flow path 32 falls within a predetermined range. When the liquid to be treated 30 flows near the outer circumferential surface of the outer cylinder 21, the magnetic sludge 31 is attracted to the outer circumferential surface of the outer cylinder 21 by the magnetic force of the magnet 23. The attracted magnetic sludge 31 moves with the rotation of the outer cylinder 21, and is separated from the liquid to be treated 30 by moving above the liquid surface of the liquid to be treated 30.

[0014] The scraper 26 contacts the outer peripheral surface of the magnet drum 20 at a position about 1 / 8 of a revolution from the top of the magnet drum 20 in the circumferential direction. No magnets 23 are disposed at the portion of the outer peripheral surface of the magnet drum 20 with which the scraper 26 is in contact. The scraper 26 functions as a removal mechanism that scrapes off the magnetic sludge 31 on the outer peripheral surface of the magnet drum 20. The magnetic sludge 31 scraped off by the scraper 26 is collected in a collection container 29 through a discharge path 28.

[0015] A roller 27 is pressed against the outer peripheral surface of the magnet drum 20 at a position from the contact point between the outer peripheral surface of the magnet drum 20 and the liquid surface of the liquid to be treated 30 to the top of the outer peripheral surface in the circumferential direction. The roller 27 rotates in the opposite direction to the rotation direction of the outer cylinder 21 by power transmitted from the rotating shaft of the outer cylinder 21 via a sprocket and a chain. An elastic body is disposed on the outer peripheral surface of the roller 27. When the magnetic sludge 31 attracted to the outer peripheral surface of the magnet drum 20 passes between the outer cylinder 21 and the roller 27, the liquid adhering to the outer peripheral surface of the outer cylinder 21 is removed. This allows the magnetic sludge 31 with a small liquid content to be separated and collected.

[0016] The pump 40 sends the liquid to be treated 30 containing the magnetic sludge 31 to the inlet 11 of the housing 10. The branch flow path 42 branches off from the main flow path 41 from the pump 40 to the inlet 11, and then merges with the main flow path 41. A detector 43 is inserted in the branch flow path 42. The detector 43 measures the content of the magnetic sludge 31 contained in the liquid to be treated 30 flowing through the branch flow path 42. For example, a suspended solids concentration meter using a laser can be used as the detector 43. The detector 43 can measure the weight concentration, volume concentration, or number of particles per unit volume of the magnetic sludge as the "magnetic sludge content". The content of the magnetic sludge 31 in the liquid to be treated 30 flowing through the main flow path 41 is almost the same as the content of the magnetic sludge 31 in the liquid to be treated 30 flowing through the branch flow path 42. The detector 43 functions as a "magnetic sludge content information acquisition device" that measures the magnetic sludge content of the liquid to be treated 30.

[0017] The measured value of the magnetic sludge 31 content is input to the control device 50. The control device 50 includes a sequencer 51 and an inverter 52. The sequencer 51 controls the inverter 52 so that the magnet drum 20 rotates at a preferred rotation speed according to the measured value of the magnetic sludge 31 content. The inverter 52 supplies driving power to the motor 25. In other words, the control device 50 controls the rotation speed of the magnet drum 20 according to the content of magnetic sludge 31 contained in the liquid 30 to be treated.

[0018] FIG. 2 is a graph showing an example of the relationship between the measured content of the magnetic sludge 31 and the target value of the rotation speed of the magnet drum 20. The horizontal axis represents the measured content of the magnetic sludge 31, and the vertical axis represents the target value of the rotation speed of the magnet drum 20. When the measured content of the magnetic sludge 31 is within the range from the reference lower limit C1 to the reference upper limit C3, the control device 50 increases the target value of the rotation speed of the magnet drum 20 as the measured content of the magnetic sludge 31 increases. For example, the target value of the rotation speed of the magnet drum 20 is determined so that the thickness of the magnetic sludge 31 adsorbed on the outer circumferential surface of the magnet drum 20 falls within the target range at the position where the roller 27 (FIG. 1) is in contact. The target range of the thickness of the magnetic sludge 31 is, for example, 0.5 mm or more and 1 mm or less.

[0019] When the measured content of magnetic sludge 31 falls below the reference lower limit C1, the target value of the rotation speed of the magnet drum 20 is set to zero. That is, when the measured content of magnetic sludge 31 falls below the reference lower limit C1, the rotation of the magnet drum 20 is stopped. When the measured content of magnetic sludge 31 reaches or exceeds the rotation start threshold C2, the rotation of the magnet drum 20 is resumed. When the measured content of magnetic sludge 31 exceeds the reference upper limit C3, the target value of the rotation speed of the magnet drum 20 is maintained at a rotation speed corresponding to the maximum allowable rotation speed of the motor 25.

[0020] 3 is a graph showing the time change of the target value of the rotation speed of the magnet drum 20 during the period when the measured content of the magnetic sludge 31 is below the reference lower limit C1 (FIG. 2). When the measured content of the magnetic sludge 31 falls below the reference lower limit C1 (FIG. 2) at time t1, the rotation of the magnet drum 20 is stopped. Thereafter, the control device 50 intermittently rotates the magnet drum 20 until the measured content of the magnetic sludge 31 becomes equal to or greater than the rotation start threshold C2. For example, the magnet drum 20 is rotated at least once every certain period T.

[0021] Next, the excellent effects of the embodiment shown in Figs. 1 to 3 will be described. When the magnet drum 20 is rotated at a constant speed regardless of the content of magnetic sludge 31, as the content of magnetic sludge 31 increases, the amount of magnetic sludge 31 attracted to the outer circumferential surface of the magnet drum 20 increases. As the layer of magnetic sludge 31 attracted to the outer circumferential surface of the magnet drum 20 becomes thicker, the magnetic force attracting the magnetic sludge 31 weakens. As a result, more magnetic sludge 31 is not attracted to the magnet drum 20 and is discharged from the discharge port 12. In other words, the ability to remove the magnetic sludge 31 decreases.

[0022] Furthermore, when the layer of magnetic sludge 31 adsorbed on the outer peripheral surface of the magnet drum 20 becomes thick, the liquid removal capacity of the roller 27 (FIG. 1) becomes insufficient for the amount of liquid adhering to the outer peripheral surface of the magnet drum 20. As a result, a large amount of liquid passes through the roller 27 and reaches the scraper 26 (FIG. 1), and is discharged together with the magnetic sludge 31.

[0023] If the layer of magnetic sludge 31 attracted to the outer peripheral surface of the magnet drum 20 becomes thicker, an excessive load is applied to the magnet drum 20 and the roller 27. The excessive load can cause failure of the drive system, such as the motor 25.

[0024] In this embodiment, when the content of magnetic sludge 31 increases, the rotation speed of the magnet drum 20 is increased to quickly remove the magnetic sludge 31 adsorbed to the outer peripheral surface of the magnet drum 20. As a result, a decrease in the adsorption force caused by excess magnetic sludge 31 being adsorbed to the outer peripheral surface of the magnet drum 20 is suppressed. This makes it possible to prevent a decrease in the ability to remove the magnetic sludge 31. Furthermore, excellent effects are obtained, such as suppressing an increase in the amount of liquid discharged together with the magnetic sludge 31 and reducing the risk of failure of the drive system.

[0025] Furthermore, when the content of magnetic sludge 31 falls below the reference lower limit C1 (FIG. 2), the rotation of the magnet drum 20 is stopped, thereby reducing energy consumption. Even if the content of magnetic sludge 31 is below the reference lower limit C1, if an extremely small amount of magnetic sludge 31 is contained, the magnetic sludge 31 is gradually attracted to the outer peripheral surface of the magnet drum 20, and the layer of magnetic sludge 31 becomes thick. In this embodiment, the magnet drum 20 is rotated intermittently even during the period when the content of magnetic sludge 31 is below the reference lower limit C1, thereby preventing the layer of magnetic sludge 31 attracted to the outer peripheral surface of the magnet drum 20 from becoming excessively thick.

[0026] Next, a modification of the embodiment shown in FIGS. 1 to 3 will be described. In the embodiment shown in Figs. 1 to 3, in the range where the magnetic sludge content exceeds the reference upper limit value C3 (Fig. 2), the target value of the rotation speed of the magnet drum 20 is constant. For this reason, a state may occur where the layer of magnetic sludge attracted to the outer peripheral surface of the magnet drum 20 becomes excessively thick. In this modified example, when the magnetic sludge content exceeds the reference upper limit value C3 (Fig. 2), the pressing force of the roller 27 (Fig. 1) on the magnet drum 20 is reduced. This makes it possible to suppress an excessive increase in the load applied to the motor 25. This makes it possible to further reduce the risk of failure of the drive system, such as the motor 25.

[0027] In the above embodiment, the sprocket and the chain are used to transmit power to the roller 27 (FIG. 1) to forcibly rotate the roller 27. Instead of transmitting power to the roller 27, the roller 27 may be configured to rotate by the frictional force between the roller 27 and the target 21.

[0028] Next, a grinding system according to another embodiment will be described with reference to Fig. 4. The grinding system according to this embodiment includes a grinding device and the magnetic separator according to the embodiment shown in Figs.

[0029] FIG. 4 is a schematic diagram of a grinding system according to this embodiment. A grinding device 60 grinds a workpiece containing a magnetic material with a grindstone while supplying a coolant liquid. The coolant liquid containing magnetic sludge discharged from the grinding device 60 is collected in a coolant tank 61. A pump 40 sucks up the coolant liquid containing magnetic sludge from the coolant tank 61 and supplies it to the magnetic separator 15. This coolant liquid corresponds to the liquid to be treated that is supplied to the magnetic separator shown in FIGS. 1 to 3. The coolant liquid from which the magnetic sludge has been removed by the magnetic separator 15 is discharged from the discharge port 12 and returned to the coolant tank 61. The coolant liquid is supplied from the coolant tank 61 to the grinding device 60 and is reused.

[0030] Next, the excellent effects of this embodiment will be described. By keeping the magnetic separator 15 in operation, the magnetic sludge can be removed from the coolant in the coolant tank 61. The coolant from which the magnetic sludge has been removed can be supplied to the grinding device 60. Since the rotation speed of the magnet drum 20 (FIG. 1) is controlled according to the magnetic sludge content of the coolant pumped up by the pump 40, when the magnetic sludge content of the coolant in the coolant tank 61 increases, the rotation speed of the magnet drum 20 increases, and the magnetic sludge removal capability increases. As a result, the magnetic sludge content of the coolant in the coolant tank 61 can be quickly reduced.

[0031] Next, a grinding system according to still another embodiment will be described with reference to Fig. 5. The grinding system according to this embodiment includes a grinding device and the magnetic separator according to the embodiment shown in Figs.

[0032] 5 is a schematic diagram of the grinding system according to this embodiment. Coolant liquid containing magnetic sludge discharged from a grinding device 60 flows into an inlet 11 of a magnetic separator 15 via a pump 40. The coolant liquid discharged from an outlet 12 is collected in a buffer tank 62. The coolant liquid collected in the buffer tank 62 is supplied to the grinding device 60 and reused.

[0033] Next, the excellent effects of this embodiment will be described. The magnetic sludge removal capacity of the magnetic separator 15 can be increased or decreased based on the magnetic sludge content of the coolant discharged from the grinding device 60. This allows the magnetic sludge removal capacity to be sufficiently achieved, and the coolant from which the magnetic sludge has been sufficiently removed can be resupplied to the grinding device 60.

[0034] Next, a magnetic separator according to still another embodiment will be described with reference to Figures 6 and 7. Below, a description of the configuration common to the embodiment shown in Figures 1 to 3 will be omitted.

[0035] Fig. 6 is a schematic diagram of the magnetic separator and grinding device according to this embodiment. In this embodiment, as in the embodiment shown in Fig. 4, the coolant discharged from the grinding device 60 is collected in the coolant tank 61, and the coolant in the coolant tank 61 is resupplied to the grinding device 60. In this embodiment, a flow rate adjustment valve 44 is inserted in the flow path from the discharge port of the pump 40 to the inlet 11 of the magnetic separator 15.

[0036] In the embodiment shown in Figures 1 to 3, the rotation speed of the motor 25 is adjusted according to the magnetic sludge content of the coolant liquid, but in this embodiment, the control device 50 controls the flow control valve 44 according to the magnetic sludge content of the coolant liquid, thereby adjusting the flow rate of the coolant liquid flowing into the inlet 11 of the magnetic separator 15.

[0037] FIG. 7 is a graph showing the relationship between the measured value of the magnetic sludge content of the coolant and the target value of the flow rate of the coolant. The horizontal axis represents the measured value of the magnetic sludge content, and the vertical axis represents the target value of the flow rate of the coolant. The control device 50 reduces the target value of the flow rate of the coolant as the measured value of the magnetic sludge content increases. For example, when the measured value of the magnetic sludge content increases from C4 to C5, the control device 50 reduces the target value of the flow rate of the coolant from F2 to F1. Conversely, when the measured value of the magnetic sludge content decreases from C5 to C4, the control device 50 increases the target value of the flow rate of the coolant from F1 to F2. When the measured value of the magnetic sludge content exceeds the allowable upper limit value C6, the control device 50 sets the target value of the flow rate of the coolant to zero. That is, the pump 40 is stopped.

[0038] Next, the excellent effects of this embodiment will be described. When the magnetic sludge content of the coolant becomes excessive, as explained in the embodiment shown in Figs. 1 to 3, a large amount of liquid is collected together with the magnetic sludge, and the risk of failure of the drive system such as the motor 25 increases. In this embodiment, when the magnetic sludge content becomes excessively large, the flow rate of the coolant is reduced. Reducing the flow rate of the coolant corresponds to reducing the magnetic sludge removal ability of the magnetic separator 15. Therefore, the layer of magnetic sludge adsorbed on the outer peripheral surface of the magnet drum 20 is prevented from becoming excessively thick. This prevents a large amount of liquid from being discharged together with the magnetic sludge, and reduces the risk of failure of the drive system such as the motor 25.

[0039] Next, a magnet separator according to still another embodiment will be described with reference to Figures 8 and 9. Hereinafter, a description of the configuration common to the embodiment shown in Figures 1 to 3 will be omitted.

[0040] FIG. 8 is a schematic diagram of the magnetic separator and the grinding device according to this embodiment. In this embodiment, as in the embodiment shown in FIG. 5, the coolant discharged from the grinding device 60 flows into the inlet 11 of the magnetic separator 15 through the pump 40. In the embodiment shown in FIGS. 1 to 3, the measured value of the magnetic sludge content of the liquid to be treated detected by the detector 43 is input to the control device 50. In contrast, in this embodiment, the grinding conditions of the grinding device 60 are input to the control device 50 from the output unit 45 of the grinding device 60. The grinding conditions include, for example, the cutting amount of the grinding wheel into the workpiece, the moving speed of the workpiece, etc. Since the amount of magnetic sludge generated depends on these grinding conditions, these grinding conditions can be said to be magnetic sludge content information related to the magnetic sludge content of the coolant. In addition, the output unit 45 has a function as a magnetic sludge content information acquisition unit.

[0041] The control device 50 determines a target value for the rotation speed of the magnet drum 20 in accordance with the grinding conditions of the grinding device 60 .

[0042] 9 is a graph showing an example of the relationship between the grinding conditions and the target value of the rotation speed of the magnet drum 20. The horizontal axis represents the product of the cutting amount of the grindstone and the moving speed of the workpiece, and the vertical axis represents the target value of the rotation speed of the magnet drum 20. The larger the cutting amount of the grindstone, the greater the amount of magnetic sludge generated, and the faster the moving speed of the workpiece, the greater the amount of magnetic sludge generated per unit time. In other words, the larger the product of the cutting amount of the grindstone and the moving speed of the workpiece, the greater the magnetic sludge content of the coolant.

[0043] When the product of the cutting amount of the grinding wheel and the movement speed of the workpiece is equal to or less than the reference upper limit value G1, the control device 50 sets the target value of the rotation speed of the magnet drum 20 to R1. When the product of the cutting amount of the grinding wheel and the movement speed of the workpiece exceeds the reference upper limit value G1, the target value of the rotation speed of the magnet drum 20 is increased from R1 to R2. When the product of the cutting amount of the grinding wheel and the movement speed of the workpiece is zero, that is, when grinding is not being performed, the target value of the rotation speed of the magnet drum 20 is set to zero, thereby stopping the rotation of the magnet drum 20.

[0044] Next, the excellent effects of this embodiment will be described. In this embodiment, as in the embodiment shown in Figures 1 to 3, the excellent effects of preventing a decrease in the recovery performance of magnetic sludge, suppressing an increase in the liquid content discharged together with the magnetic sludge, and reducing the risk of failure of the drive system can be obtained.

[0045] In the above embodiment, a drum-type magnetic separator having a magnetic drum was exemplified, but the technical idea of ​​changing the magnetic sludge removal capacity according to the magnetic sludge content can also be applied to magnetic separators of other structures, for example, conveyor-type magnetic separators.

[0046] The above-mentioned embodiments are merely examples, and it goes without saying that partial replacement or combination of the configurations shown in different embodiments is possible. Similar effects due to similar configurations of multiple embodiments are not mentioned in each embodiment. Furthermore, the present invention is not limited to the above-mentioned embodiments. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible. [Explanation of symbols]

[0047] 10. Chassis 11 Inlet 12 Outlet 15 Magnetic separator 20 Magnet Drum 21 Outer cylinder 22 Inner cylinder 23 Magnet 25 Motor 26 Scraper 27 Lola 28 Exhaust channel 29 Collection container 30 Liquid to be treated 31 Magnetic sludge 32 Flow path for treated liquid 40 Pump 41 Main Channel 42 Branch Channel 43 Detector 44 Flow Control Valve 45 Output section 50 Control device 51 Sequencer 52 Inverter 60 Grinding Equipment 61 Coolant tank 62 Buffer Tank

Claims

1. a magnetic drum whose outer circumferential surface is partially immersed in the flow of the liquid to be treated containing magnetic sludge and which rotates while generating a magnetic force on the outer circumferential surface; a removing mechanism that removes magnetic sludge on the outer peripheral surface of the magnet drum from the outer peripheral surface of the magnet drum; a magnetic sludge content information acquisition device that acquires magnetic sludge content information relating to the amount of magnetic sludge contained in the liquid to be treated; a control device that changes the magnetic sludge removal capacity of the magnet drum in accordance with the magnetic sludge content information acquired by the magnetic sludge content information acquisition device; and The control device controls the thickness of the magnetic sludge attracted to the outer peripheral surface of the magnetic drum so that it falls within a target range.

2. the magnetic sludge content information acquisition device measures the content of magnetic sludge contained in the liquid to be treated, 2. The magnetic separator according to claim 1, wherein the control device changes the magnetic sludge removal capacity of the magnetic drum in accordance with the magnetic sludge content measured by the magnetic sludge content information acquisition device.

3. The magnetic separator of claim 2, wherein the control device increases the rotation speed of the magnetic drum when the magnetic sludge content measured by the magnetic sludge content information acquisition device increases, thereby increasing the magnetic sludge removal capability.

4. 4. The magnetic separator according to claim 3, wherein the control device stops the rotation of the magnetic drum when the content of magnetic sludge measured by the magnetic sludge content information acquisition device falls below a reference lower limit value.

5. the liquid to be treated is a coolant liquid used in a grinding device, The grinding device grinds the surface of a workpiece containing a magnetic material with a grinding wheel while supplying a coolant liquid, and discharges the coolant liquid containing magnetic sludge generated during grinding as the liquid to be treated, 2. The magnetic separator according to claim 1, wherein the magnetic sludge content information includes grinding conditions of the grinding device.

6. acquiring magnetic sludge content information relating to the content of magnetic sludge contained in the liquid to be treated flowing into a magnetic separator having a magnetic drum whose outer peripheral surface is partially immersed in the flow of the liquid to be treated and which rotates while generating a magnetic force on the outer peripheral surface; A magnetic sludge removal method that changes the magnetic sludge removal ability of the magnetic separator according to the acquired magnetic sludge content information so that the thickness of the magnetic sludge adsorbed to the outer surface of the magnetic drum falls within a target range.

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