JP6962407B2 - Concentration measuring method and concentration measuring device - Google Patents

Description

The present invention relates to a concentration measuring method and a concentration measuring device.

For example, a thickener (precipitation concentrator) is used in the production of nickel powder (see, for example, Patent Document 1). Thickeners are industrial devices that settle a small amount of solid particles dispersed and mixed in a liquid by the action of gravity and continuously separate them from the liquid as high-concentration sludge (slurry).

In order to improve the controllability of separation by the thickener, it is desirable to be able to measure the concentration distribution of the slurry in the depth direction in the thickener tank. However, no technique is known for measuring such a concentration distribution.

Japanese Unexamined Patent Publication No. 2020-12184

An object of the present invention is to provide a concentration measurement technique applicable to the measurement of a slurry concentration distribution in a thickener tank in the depth direction.

According to one aspect of the invention
A step of distorting the strained body by moving the strained body in a mixture in which solids are dispersed in a liquid and measuring the strain amount of the strained body.
A step of obtaining the concentration of the solid content in the mixture based on the strain amount, and
A concentration measuring method is provided.

According to another aspect of the invention
A function of distorting the strained body by moving the strained body in a mixture in which solids are dispersed in a liquid and measuring the strain amount of the strained body.
A function of obtaining the concentration of the solid content in the mixture based on the amount of strain, and
A concentration measuring device is provided.

A concentration measurement technique applicable to the measurement of the slurry concentration distribution in the depth direction in the thickener tank is provided.

FIG. 1 (a) is a schematic view illustrating a concentration measuring device according to the first embodiment of the present invention, and FIG. 1 (b) is a schematic diagram illustrating a strain sensor attached to a strained body. FIG. 2 is a graph illustrating a time change in the amount of movement of the support member when strain movement is performed as a simple vibration. FIG. 3 is a flowchart schematically showing a concentration measuring method according to the first embodiment. 4 (a) to 4 (c) are tables and graphs showing the results of the medium- and high-concentration tests of the test examples. 5 (a) to 5 (c) are tables and graphs showing the results of the low concentration test of Test Examples. FIG. 6A is a schematic diagram illustrating a concentration distribution measuring device according to the second embodiment, and FIG. 6B is a schematic diagram illustrating a concentration distribution measuring device according to a modified example of the second embodiment. .. 7 (a) and 7 (b) are flowcharts schematically showing the concentration distribution measurement method according to the second embodiment. FIG. 8A is a schematic view illustrating a concentration measuring device according to one modification of the first embodiment, and FIG. 8B illustrates a concentration measuring device according to another modification of the first embodiment. It is a schematic diagram.

<First Embodiment>
The concentration measuring apparatus and the concentration measuring method according to the first embodiment of the present invention will be described. FIG. 1A is a schematic view illustrating the concentration measuring device 100 (hereinafter, also referred to as device 100) according to the first embodiment.

The device 100 includes a strained body 10, a support member 20, a moving mechanism 30, a strain sensor 40, and a control device 50. As will be described in detail later, the apparatus 100 distorts the strained body 10 by moving the strained body 10 immersed in the slurry (mixture in which solids are dispersed in a liquid) 1 by a moving mechanism 30. This is an apparatus for measuring the solid content concentration of the slurry 1 by measuring the strain amount of the strained body 10.

The slurry 1 is not particularly limited, but is, for example, a slurry housed in a thickener tank used for producing nickel powder. The ratio of the weight of the solid content contained in the unit volume of the slurry 1 to the weight per unit volume of the slurry 1 is the concentration of the solid content (Solid%) in the slurry 1. The concentration of the solid content in the slurry 1 may be hereinafter referred to as the slurry concentration or simply the concentration.

In the concentration measurement, the slurry 1 is housed in the container 2. The container 2 is not particularly limited, but is, for example, a thickener tank as described in the second embodiment described later.

When the container 2 is, for example, a thickener tank, the depth of the container 2 is about 5 m to 10 m, and due to gravity, the concentration of the slurry 1 increases toward the deeper side in the depth direction. There is a concentration distribution. When the concentration distribution of the slurry 1 occurs in the depth direction, the strain is measured by arranging the strained body 10 at the measurement depth (see arrow 11), which is the depth to be measured. The concentration at depth can be measured.

The movement (see arrow 12) for arranging the strained body 10 at the measurement depth in the slurry 1 is also referred to as a depth movement. Further, the direction in which the strained body 10 is moved during the depth movement is also referred to as the depth movement direction. The movement for distorting the strained body 10 in the slurry 1 (see arrow 13) is also referred to as strain movement. Further, the direction in which the strained body 10 is moved during strain movement is also referred to as a strain movement direction.

The strained body 10 is attached to the support member 20, and the support member 20 is attached to the moving mechanism 30. The strained body 10 can be moved by the moving mechanism 30 moving the support member 20. In this example, the depth movement direction and the strain movement direction are matched. Thereby, both the depth movement and the strain movement can be performed by using the movement mechanism 30 that moves the support member 20 in one direction (uniaxial direction). That is, it is not necessary to separately provide the moving mechanism for the depth movement and the moving mechanism for the strain movement, and the depth movement and the strain movement can be performed by the common moving mechanism 30, which is economical. Is. The support member 20 has, for example, a rod-like shape extending in the depth moving direction and the strain moving direction, and is made of, for example, metal.

In this example, the moving mechanism 30 specifically moves the support member 20 in the vertical direction (vertical direction). That is, the depth moving direction and the strain moving direction are set to the vertical direction. If the moving direction by the moving mechanism 30 is a direction having a vertical component (other than the horizontal direction), the depth movement can be performed, so that the moving direction is not limited to the vertical direction. That is, the depth moving direction and the strain moving direction may be diagonal directions inclined from the vertical direction. However, by setting the moving direction to the vertical direction, the depth movement can be efficiently performed.

The strained body 10 preferably has a plate-like shape, for example, and is held by the support member 20 in the shape of a cantilever. The strained body 10 is preferably made of, for example, stainless steel from the viewpoint of increasing the strength of the strained body 10 and increasing the resistance to acids and alkalis. Dimensions such as the thickness and length of the strained body 10 may be appropriately selected so that appropriate strain is generated in the slurry 1 by strain transfer. The thickness of the strained body 10 is, for example, 0.05 mm to 0.5 mm, and the length of the strained body 10 (the portion protruding and distorted like a cantilever) is, for example, 20 mm to 100 mm. ..

The thickness direction of the strained body 10 (at rest) is substantially parallel to the strain moving direction, that is, the strained body 10 can be moved in the thickness direction of the strained body 10 during the strain movement. preferable. By making the thickness direction of the strained body 10 substantially parallel to the strain moving direction, the strained body 10 can be efficiently distorted by the strain movement. Here, the fact that a certain direction and another direction are substantially parallel means that the angle formed by these directions is 20 ° or less.

In this example, the strain transfer is specifically performed by reciprocating (vibrating) the strained body 10 in one direction in the slurry 1. By reciprocating the strained body 10 up and down with the measurement depth in between, the concentration is measured at the measurement depth.

By reciprocating the strained body 10 as the strain movement, that is, by reciprocating the root portion of the strained body 10 (the end portion on the side where the strained body 10 is attached to the support member 20). The tip end portion of the strained body 10 (the end portion on the side opposite to the side where the strained body 10 is attached to the support member 20) is periodically deformed up and down (see arrow 14).

By causing the strained body 10 to perform strain movement, which is a reciprocating movement, the strained body 10 can be made to generate strain that changes periodically at a period equal to the reciprocating movement. In this example, the strain amplitude (hereinafter, also referred to as strain amplitude) of the strained body 10 that changes periodically with the reciprocating movement during the strain movement is measured as the strain amount.

By reciprocating the strained body 10 as the strain transfer, it is possible to repeatedly measure the maximum strain, which is an amount corresponding to the concentration of the slurry 1, as the amplitude of the strain that changes periodically, and the accuracy of the concentration measurement is improved. Is planned. In order to obtain the maximum strain (strain amplitude) in the reciprocating movement repeatedly and with good reproducibility, it is preferable that the strain (deformation) generated in the strained body 10 is limited to the range of elastic deformation.

The strain sensor 40 is a sensor that measures the strain of the strained body 10, and is attached to the strained body 10. As the strain sensor 40, for example, it is preferable to use a monolithic strain gauge. As a result, the temperature of the strain gauge can be compensated in the semiconductor chip, and the measurement data can be digitally converted, so that the measurement can be performed with the influence of disturbance reduced.

FIG. 1B is a schematic view illustrating a strain sensor 40 attached to the strained body 10. The strain sensor 40 includes a semiconductor chip 41, a metal bonding layer 42, a support metal plate 43, a flexible printed wiring board 44, a sealant 45, and a wiring 46. The semiconductor chip 41 on which the strain detection circuit is formed is held by the support metal plate 43 via the metal bonding layer 42. Further, the semiconductor chip 41 is connected to the flexible printed wiring board 44 attached to the support metal plate 43 via the wiring 46. A sealant 45 is formed so as to cover the ends of the semiconductor chip 41 and the flexible printed wiring board 44. The support metal plate 43 is attached to the strained body 10.

When a large strain is repeatedly generated in the strained body 10, the strain sensor 40 may malfunction due to the joint between the semiconductor chip 41 and the metal bonding layer 42 or the metal bonding layer 42 and the supporting metal plate 43 being broken. Is a concern. Therefore, it is preferable that at least one of the amplitude and the frequency (speed) in the reciprocating movement during the strain movement is set so that the strain amount (strain amplitude) is equal to or less than a predetermined maximum value.

The reciprocating motion during strain transfer is preferably a simple vibration centered on the measurement depth. The maximum strain (strain amplitude) can be measured more accurately by using simple vibration. FIG. 2 is a graph illustrating a time change of the movement amount (stroke amount) of the support member 20 by the movement mechanism 30 when the strain movement is performed as a simple vibration. An example is shown in which the center position of simple vibration is set to 20 mm, the amplitude of strain movement (single amplitude) is set to 20 mm, and the frequency of strain movement is set to 0.5 Hz. By performing the strain movement as a simple vibration, the shape of the graph in which the movement amount of the support member 20 is plotted against time becomes a sinusoidal shape. That is, the amount of movement changes in a sinusoidal manner with respect to time.

By performing the strain transfer as a simple vibration, the strain of the strained body 10 can be generated so as to change in a (almost) sinusoidal shape with time. By changing the strain of the strained body 10 in a sinusoidal manner with respect to time, the amount of strain can be measured accurately. The method for measuring the strain amount will be described later. In order to generate such a strain that changes in a sinusoidal shape of the strained body 10, it is preferable that the frequency of strain transfer is larger than the natural frequency of the strained body 10. However, if the frequency of strain transfer is too high, the amplitude becomes small and a higher-order vibration mode occurs. Therefore, it is preferable to make the frequency smaller than twice the natural frequency.

The control device 50 controls a device such as the moving mechanism 30 so as to perform a predetermined operation. Further, the control device 50 receives the data corresponding to the strain of the strained body 10 measured by the strain sensor 40, and calculates the strain amount. Further, the control device 50 includes a storage unit that stores the correspondence between the strain amount of the strained body 10 and the concentration of the slurry 1, and calculates the concentration of the slurry 1 based on the strain amount and the correspondence. When performing concentration distribution measurement as described in the second embodiment described later, the control device 50 stores the measured concentrations at a plurality of measurement depths and calculates the concentration distribution. The control device 50 is composed of, for example, a personal computer.

FIG. 3 is a flowchart schematically showing a concentration measuring method according to the first embodiment. First, in step S110, the strained body 10 is distorted by moving the strained body 10 in the slurry 1, and the strain amount of the strained body 10 is measured.

In this example, as the strain movement, the strained body 10 is reciprocated by a simple vibration to cause the strained body 10 to generate a strain that changes in a sinusoidal shape with time. Then, the strain amplitude is measured as the strain amount of the strained body 10.

In this example, the amount of strain (strain amplitude) is calculated by measuring three measurement times in which the phases are shifted by 120 ° in one cycle as one set. Further, preferably, the amount of strain obtained by shifting the phase of each set a plurality of times with three measurement times shifted by 120 ° in one cycle as one set is performed, and the amount of strain obtained by each measurement is performed. Is calculated to calculate the average amount of strain. Hereinafter, a specific description will be given.

The strain is expressed as Asin θ, where the amplitude and phase of the sinusoidally changing strain are A and θ, respectively. Strain in the three first measurement time included in one set, the phase as theta _1, represented as A sin .theta _1. strain from theta ₁ of the measurement time in phase apart 120 °, and, the strain from theta ₁ of the measurement time in phase apart 240 °, respectively, measured as strain at second and third measurement points. The strains at the second and third measurement points are represented as Asin (θ ₁ + 120 °) and Asin (θ ₁ + 240 °), respectively.

For any phase theta _1, that is, even the phase theta ₁ is unknown, as long as a _{Asinθ 1, Asin (θ 1 +} 120 °) and three values is one set of _{Asin (θ 1 + 240 °)} , trigonometric The amplitude A can be calculated using the property of. In this way, the strain amount (strain amplitude) is calculated by performing the measurement with the three measurement times whose phases are shifted by 120 ° in one cycle as one set.

Amplitude A can be calculated if, as at least one set, strains at three measurement times that are out of phase by 120 ° are obtained. Further, from the viewpoint of improving the measurement accuracy of the amplitude A, it is preferable to calculate the averaged amplitude A by averaging the amplitudes A obtained from a plurality of sets measured by shifting the phase.

For example, the strain is measured at predetermined time intervals (for example, _{every 10 ° from a certain phase θ 1} ), and a plurality of sets composed of strains at three measurement times whose phases are shifted by 120 ° are acquired. Specifically, for example, the first set _{, Asin θ 1} , Asin (θ ₁ + 120 °) and Asin (θ ₁ + 240 °), and the second set, Asin (θ ₁ + 10 °), Asin (θ). ₁ + 130 °) and Asin (θ ₁ + 250 °), etc. are acquired. Then, the amplitude A is calculated from each set, and the average amplitude A, that is, the average amount of strain is obtained by averaging these amplitudes A.

After measuring the strain amount of the strained body 10 in step S110, the concentration of the slurry 1 is acquired in step S120 based on the strain amount. Specifically, the control device 50 obtains the concentration of the slurry 1 by associating the strain amount of the strained body 10 with the concentration of the slurry 1 based on the correspondence stored in the storage unit. In this way, the concentration of slurry 1 is measured.

As described above, according to the first embodiment, the strained body 10 is distorted by moving the strained body 10 immersed in the slurry 1, and the strain amount of the strained body 10 is measured. Thereby, the concentration of the slurry 1 can be measured.

Further, according to the first embodiment, various conditions such as dimensions such as thickness and length of the strained body 10, amplitude of reciprocating movement in strain movement, frequency (speed) and the like are appropriately adjusted. The concentration with respect to the solid content concentration can be measured by a device having a simple mechanism.

As a conventional concentration measuring device, there are an ultrasonic densitometer, a rheometer, and the like. However, with an ultrasonic densitometer, it is difficult to measure from a low concentration to a high concentration with one ultrasonic densitometer. In addition, the rheometer has a complicated structure, and it is difficult to operate the rheometer stably in an environment such as in a thickener tank.

As confirmed in the test examples described below, the concentration measuring device 100 according to the first embodiment has a simple mechanism of distorting the strained body 10, but adjusts at least one of the amplitude and frequency of strain transfer. By doing so, it is possible to measure from a low concentration to a high concentration using the same device 100 (same strained body 10). Therefore, as will be described in the second embodiment described later, for example, it can be preferably used as a concentration measuring device for acquiring a concentration distribution in the depth direction in a thickener tank.

<Test example>
Next, a test example in which it has been confirmed that the solid content concentration in the slurry can be accurately measured by the method as described above will be described. In this test example, a measurement test for a medium / high concentration slurry (hereinafter, also referred to as a medium / high concentration test) and a measurement test for a low concentration slurry (hereinafter, also referred to as a low concentration test) were performed. In the medium / high concentration test and the low concentration test, a dispersion liquid in which red clay was dispersed in water was used as the slurry.

In the medium / high concentration test and the low concentration test, the strained body was reciprocated in the vertical direction with a simple vibration in a slurry having a known concentration, and the amplitude of the strain generated in the strained body was measured. Then, the correspondence between the slurry concentration and the strain amplitude of the strained body was investigated.

The medium / high concentration test will be described with reference to FIGS. 4 (a) to 4 (c). In the medium / high concentration test, the slurry concentration (unit: Solid%) was changed from 22.61% to 48.52% as shown in the left column of the table in FIG. 4 (a). Further, in the medium- and high-concentration tests, a strained body having a thickness of 0.1 mm and a length of 80 mm was used, and a simple vibration having a total amplitude of 40 mm and a frequency of 0.25 Hz was performed as strain transfer.

The right column of the table in FIG. 4A shows the strain amplitude (unit: μst) measured at each concentration in the medium and high concentration tests. In a situation where there is little noise, the strain amplitude may be full amplitude (peak to peak) or single amplitude (zero to peak), if necessary. Here, the total amplitude is used as the strain amplitude.

4 (b) and 4 (c) are graphs showing the strain amplitude with respect to the slurry concentration in the medium / high concentration test. The slurry concentration is shown in real numbers in both FIGS. 4 (b) and 4 (c), and the strain amplitude is shown in real numbers in FIG. 4 (b) and logarithmically in FIG. 4 (c). FIG. 4 (b) and FIG. 4 (c), approximate expression by an exponential function, the coefficient of determination ^(R 2), and show the approximate curve (dotted line).

The low concentration test will be described with reference to FIGS. 5 (a) to 5 (c). In the low concentration test, the slurry concentration (unit: Solid%) was changed from 0% (Water) to 28.34% as shown in the left column of the table in FIG. 5 (a). Further, in the low concentration test, a strained body having a thickness of 0.1 mm and a length of 80 mm was used, and a simple vibration having a total amplitude of 5 mm and a frequency of 8 Hz was performed as strain transfer.

Compared to medium- and high-concentration slurries, low-concentration slurries are less likely to cause strain on the strained body due to strain transfer. The frequency is higher than that of the concentration test. As a result, the amount of strain (strain amplitude) at low concentrations can be increased, so that measurement errors can be reduced. The right column of the table in FIG. 5A shows the strain amplitude (total amplitude, unit μst) measured at each concentration in the low concentration test.

5 (b) and 5 (c) are graphs showing the strain amplitude with respect to the slurry concentration in the low concentration test. The slurry concentration is shown in real numbers in both FIGS. 5 (b) and 5 (c), and the strain amplitude is shown in real numbers in FIG. 5 (b) and logarithmically in FIG. 5 (c). In FIGS. 5 (b) and FIG. 5 (c), the approximate expression by an exponential function, the coefficient of determination ^(R 2), and show the approximate curve (dotted line). The results at a slurry concentration of 0% (that is, water) are excluded from the graph display because of the large error. However, it is considered that this error can be reduced by optimally adjusting the dimensions of the strained body, the conditions for strain movement, and the like.

It can be seen that the strain amplitude with respect to the slurry concentration can be accurately approximated by the exponential function in both the medium / high concentration test and the low concentration test. That is, it can be seen that the strain amplitude can be calculated accurately for an arbitrary slurry concentration. Therefore, in other words, the slurry concentration can be calculated accurately for an arbitrary strain amplitude.

From this, specifically, the concentration of the slurry can be measured as follows. First, the correspondence between the strain amplitude and the slurry concentration is obtained in advance by a preliminary experiment such as this test example. Then, the corresponding relationship is stored in the storage unit of the control device of the concentration measuring device. In the concentration measurement, the strain amplitude of the strained body is measured by moving the strained body in the slurry, and further, the slurry concentration is calculated from the measured strain amplitude using the corresponding relationship.

<Modified example of the first embodiment>
As described above, the concentration measurement according to the present embodiment is based on the fact that the magnitude of the maximum strain of the strained body 10 changes according to the concentration of the slurry 1, and the slurry 1 is strained so that the strained body 10 is strained. This can be done by moving the strained body 10 inside.

Therefore, the strain movement (movement of the strained body 10 in the slurry 1) is not limited to the reciprocating movement, and may be a one-way movement. That is, even if the concentration of the slurry 1 is measured based on the correspondence between the magnitude of the maximum strain generated in the strained body 10 by moving the strained body 10 one way in the slurry 1 and the concentration of the slurry 1. good.

Further, in the above-mentioned example, the linear direction is exemplified as the strain moving direction (one direction in which the strained body 10 is moved in the slurry 1), and the vertical direction (vertical direction) is exemplified as an example of the linear direction. However, from the viewpoint of measuring the concentration of the slurry 1, the strain moving direction is not particularly limited as long as the strained body 10 can be moved in the slurry 1. For example, when the strain moving direction is a linear direction, it may be other than the vertical direction. Further, the strain moving direction is not limited to the linear direction, and may be, for example, the circumferential direction of the rotational motion.

FIG. 8A is a schematic view illustrating a concentration measuring device 100 (hereinafter, also referred to as a device 100) in a mode in which a reciprocating movement (swing) is performed in the circumferential direction as a strain movement, and the device 100 is viewed from above. Indicates the state. The strained body 10 of this modification is attached to a support member 20 that rotates around a rotation axis extending in the vertical direction (vertical direction), and reciprocates (swings) in the circumferential direction by a moving mechanism 30. ) (See arrow 13). The strain moving direction in this modification can be said to be the horizontal direction, and the strained body 10 is preferably arranged so that the thickness direction is the horizontal direction.

In the modified example shown in FIG. 8A, the moving mechanism 30 may include a moving mechanism for performing depth movement in addition to the moving mechanism for performing strain movement. From the viewpoint that the concentration can be measured, the moving mechanism for moving the depth may be omitted.

Moving the strained body 10 in the slurry 1 is not limited to the mode in which the strained body 10 is moved by the moving mechanism 30 as in the above example, and is performed in the moving (flowing) slurry 1. It may be carried out in the manner of arranging the strained body 10. That is, the "movement" when the strained body 10 is distorted by moving the strained body 10 in the slurry 1 means that the strained body 10 is relatively moved in the slurry 1 (relative to the slurry 1). Means.

FIG. 8B is a schematic view illustrating a concentration measuring device 100 in which the strained body 10 is arranged in the moving slurry 1. In this modification, the flow generation mechanism 15 that generates the flow of the slurry 1 generates the flow of the slurry 1 under predetermined conditions (predetermined direction, flow velocity, etc.) (see arrow 13). Then, by arranging the strained body 10 in the flow, the strained body 10 is (relatively) moved in the slurry 1, that is, the strain is moved.

<Second Embodiment>
Next, the concentration distribution measuring device and the concentration distribution measuring method according to the second embodiment will be described. In the second embodiment, one embodiment of measuring the concentration distribution is illustrated by applying the concentration measuring device and the concentration measuring method described in the first embodiment. FIG. 6A is a schematic view illustrating the concentration distribution measuring device 200 (hereinafter, also referred to as the device 200) according to the second embodiment.

The device 200 is similar to the device 100 described in the first embodiment (see FIG. 1A). The device 200 measures the concentration of the slurry 1 contained in the tank 211 of the thickener 210. That is, the apparatus 200 measures the concentration by arranging the strained body 10 in the tank 211 of the thickener 210.

As described above, in the tank 211 of the thickener 210, the concentration distribution of the slurry 1 is generated in the depth direction. The apparatus 200 can arrange the strained body 10 at a plurality of measurement depths by moving the depth, whereby the concentration of the slurry 1 can be measured at each measurement depth. By measuring the concentration of the slurry 1 at a plurality of measurement depths, it is possible to measure the concentration distribution in the depth direction of the thickener 210 in the tank 211.

7 (a) and 7 (b) are flowcharts schematically showing the concentration distribution measurement method according to the second embodiment. In the concentration distribution measurement method according to the second embodiment, in step S200 (see FIG. 7A), the concentration measurement step is carried out for a plurality of measurement depths to obtain the concentration distribution in the depth direction in the slurry 1. get.

The concentration measuring step according to the second embodiment includes a step in which step S210, step S220, and step S230 are set as one set (see FIG. 7B). In step S210, the strained body 10 is arranged at the measurement depth in the slurry 1. In step S220, the strained body 10 arranged at the measurement depth is moved in the slurry 1 to distort the strained body 10, and the strain amount of the strained body 10 is measured. In step S230, the concentration of the slurry 1 at the measurement depth is acquired based on the strain amount.

In step S200 according to the second embodiment, the same strained body 10 is sequentially arranged at a plurality of measurement depths, so that the concentration measurement steps are sequentially performed for the plurality of measurement depths. In the second embodiment, the concentration distribution is measured in this way. At this time, the order of depth movement of the strained body 10 is not particularly limited. For example, the strained body 10 may be moved from the upper side to the lower side, or the strained body 10 may be moved from the lower side to the upper side, for example.

As described above, in the apparatus 200 of this example, the depth moving direction in step S200 (that is, the moving direction when moving the strained body 10 between a plurality of measurement depths) and the strain moving direction in step S220. (That is, the moving direction in which the strained body 10 is moved in the slurry 1 in order to distort the strained body 10) and. As a result, the moving mechanism used for depth movement and the moving mechanism used for strain movement can be made into a common moving mechanism 30. If necessary, a moving mechanism used for depth movement and a moving mechanism used for strain movement may be provided as separate moving mechanisms.

The thickener 210 is provided with a rake 212 in the tank 211. When the concentration is measured at a deep position in the tank 211, there is a concern that the strained body 10 may interfere with the arm 214 of the rake 212 and the scraping portion 213. In such a case, in a plan view viewed from a line of sight parallel to the rotation axis of the rake 212, the strained body 10 is not passed through the position of the strained body 10 in the plane by the arm 214 or the scraping portion 213. The concentration is measured by lowering 10 to a deep position where it interferes with the arm 214 and the scraping portion 213. Further, during the period during which the arm 214 and the scraping portion 213 pass through the arrangement position, the strained body 10 is raised to a shallow position so as not to interfere with the arm 214 and the scraping portion 213, thereby raising the strained body 10. Evacuate.

<Modified example of the second embodiment>
FIG. 6B is a schematic view illustrating the apparatus 200 according to the modified example of the second embodiment. The device 200 of this modification has a structure in which the strained body 10 is attached to a plurality of positions in the depth direction of the support member 20. In step S200 according to this modification, by arranging the strained body 10 at each of a plurality of measurement depths using such a structure, a concentration measurement step is simultaneously performed for the plurality of measurement depths. In this modification, the concentration distribution is measured in this way.

In the tank 211 of the thickener 210, the concentration distribution of the slurry 1 is generated so that the deeper the side, the higher the concentration. Further, as described in the above-mentioned test example, the strain of the strained body 10 is less likely to be generated on the lower concentration side. Therefore, in this modification, in the strained body 10 arranged at a plurality of depths, the strained body 10 arranged on the shallow side (upward), that is, the strained body 10 arranged on the low concentration side. Is to have a shape that is more likely to be distorted than the strained body 10 arranged on the deep side (downward), that is, the strained body 10 arranged on the high concentration side, for example, a long shape. , Are preferred.

In this modification, the strained bodies 10 arranged at the plurality of measurement depths are used, and the densities at the plurality of measurement depths are measured by one concentration measurement (with one strain transfer). It is possible to measure the concentration distribution. However, in order to obtain the concentration distribution with higher accuracy in the depth direction, the measurement depth may be changed by moving the depth, and the concentration measurement may be performed a plurality of times (strain movement a plurality of times).

As described above, according to the second embodiment, the concentration distribution of the slurry 1 in the depth direction in the tank 211 of the thickener 210 can be measured. The measured concentration distribution is, for example, when controlling the concentration distribution so as to increase the amount of water supplied to the tank 211 of the thickener 210 as much as possible while increasing the concentration of sludge (slurry) at the bottom of the tank 211 as much as possible. Can be used as an index.

The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the above-described embodiment, and various changes, improvements, combinations, and the like can be made without departing from the gist thereof.

<Preferable Aspect of the Present Invention>
Hereinafter, preferred embodiments of the present invention will be added.

(Appendix 1)
A step of distorting the strained body by moving the strained body in a mixture in which solids are dispersed in a liquid and measuring the strain amount of the strained body.
A step of obtaining the concentration of the solid content in the mixture based on the strain amount, and
Concentration measurement method.

(Appendix 2)
In the step of measuring the amount of strain, the strained body is distorted by reciprocating the strained body in one direction in the mixture, and the strained body that changes periodically with the reciprocating movement of the strained body. The concentration measuring method according to Appendix 1, wherein the strain amplitude is measured as the strain amount.

(Appendix 3)
The concentration measuring method according to Appendix 1 or 2, wherein the reciprocating motion is simple vibration.

(Appendix 4)
In the step of measuring the amount of strain, the strain of the strained body, which changes periodically due to the simple vibration, is measured as one set at three measurement times in which the phases are shifted by 120 ° in one cycle. The concentration measuring method according to Appendix 3, wherein the strain amount is measured.

(Appendix 5)
In the step of measuring the amount of strain, the amount of strain is measured a set of three measurement times in which the phases are shifted by 120 ° in one cycle, and the phase of each set is shifted a plurality of times. By averaging the amount of strain obtained, the average amount of strain is calculated.
The concentration measuring method according to Appendix 4, wherein in the step of acquiring the concentration of the solid content, the concentration of the solid content in the mixture is acquired based on the average amount of strain.

(Appendix 6)
The concentration measuring method according to any one of Supplementary note 2 to 5, wherein the amplitude of the reciprocating movement is set so that the strain amount is equal to or less than a predetermined maximum value.

(Appendix 7)
The concentration measuring method according to any one of Supplementary note 2 to 6, wherein the frequency of the reciprocating movement is set so that the strain amount is equal to or less than a predetermined maximum value.

(Appendix 8)
The concentration measuring method according to any one of Supplementary note 1 to 7, wherein the strained body is made of stainless steel.

(Appendix 9)
The concentration measuring method according to any one of Supplementary note 1 to 8, wherein a monolithic strain gauge attached to the strained body is used as a sensor for measuring the strain of the strained body.

(Appendix 10)
The strained body has a plate-like shape and is held by a support member in the shape of a cantilever.
In the step of measuring the amount of strain, the concentration according to any one of Supplementary note 1 to 9, wherein the strained body is distorted by moving the strained body in the thickness direction of the strained body. Measuring method.

(Appendix 11)
A function of distorting the strained body by moving the strained body in a mixture in which solids are dispersed in a liquid and measuring the strain amount of the strained body.
A function of obtaining the concentration of the solid content in the mixture based on the amount of strain, and
Concentration measuring device.

1 ... slurry, 2 ... container, 10 ... strained body, 20 ... support member, 30 ... moving mechanism, 40 ... strain sensor, 50 ... control device, 100 ... concentration measuring device, 200 ... concentration distribution measuring device, 210 ... thickener , 211 ... tank, 212 ... rake, 213 ... scraping part, 214 ... arm

Claims (10)

A step of distorting the strained body by moving the strained body in a mixture in which solids are dispersed in a liquid and measuring the strain amount of the strained body.
A step of obtaining the concentration of the solid content in the mixture based on the strain amount, and
Have a,
In the step of measuring the amount of strain, the strained body is distorted by reciprocating the strained body in one direction in the mixture, and the strained body that changes periodically with the reciprocating movement of the strained body. A concentration measuring method in which a strain amplitude is measured as the strain amount. The concentration measuring method according to claim 1, wherein the reciprocating motion is simple vibration. In the step of measuring the amount of strain, the strain of the strained body, which changes periodically due to the simple vibration, is measured as one set at three measurement times in which the phases are shifted by 120 ° in one cycle. The concentration measuring method according to claim 2 , wherein the strain amount is measured. In the step of measuring the amount of strain, the amount of strain is measured a set of three measurement times in which the phases are shifted by 120 ° in one cycle, and the phase of each set is shifted a plurality of times. By averaging the amount of strain obtained, the average amount of strain is calculated.
The concentration measuring method according to claim 3 , wherein in the step of obtaining the concentration of the solid content, the concentration of the solid content in the mixture is obtained based on the average amount of strain. The concentration measuring method according to any one of claims 1 to 4 , wherein the amplitude of the reciprocating movement is set so that the strain amount is equal to or less than a predetermined maximum value. The concentration measuring method according to any one of claims 1 to 5 , wherein the frequency of the reciprocating movement is set so that the strain amount is equal to or less than a predetermined maximum value. The concentration measuring method according to any one of claims 1 to 6 , wherein the strained body is made of stainless steel. The concentration measuring method according to any one of claims 1 to 7 , wherein a monolithic strain gauge attached to the strained body is used as a sensor for measuring the strain of the strained body. The strained body has a plate-like shape and is held by a support member in the shape of a cantilever.
The step according to any one of claims 1 to 8 , wherein in the step of measuring the amount of strain, the strained body is distorted by moving the strained body in the thickness direction of the strained body. Concentration measurement method. The strained body is distorted by reciprocating the strained body in one direction in a mixture in which solids are dispersed in a liquid, and the strain amplitude of the strained body changes periodically with the reciprocating movement. With the function of measuring as the amount of strain of the strained body,
A function of obtaining the concentration of the solid content in the mixture based on the amount of strain, and
Concentration measuring device having.

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