Measuring device and measuring method

Abstract

To provide a measuring device and method capable of measuring the size of a solid even in an opaque fluid. [Solution] The measuring device 1 is a device for measuring a solid S in a fluid L, and includes a transmitting transducer 11 that transmits an ultrasonic signal, a receiving transducer 12 that is positioned opposite the transmitting transducer 11 across the fluid L and receives the transmitted signal of the ultrasonic signal that has passed through the fluid L, and the length d of the solid S along the ultrasonic signal propagation path P, based on the time from when the ultrasonic signal is transmitted from the transmitting transducer 11 until the transmitted signal is received by the receiving transducer 12. s The system includes a signal processing device 14 for calculating signals.

Description

Technical Field

[0001] The present disclosure relates to a measuring device and a measuring method.

Background Art

[0002] In energy plants, chemical plants, food production, etc., transportation of solid energy resources through pipelines, as well as mixing and stirring of solids in reactors are commonly performed. At this time, in the processes of transportation, mixing, and stirring, grasping the size of solids flowing in a liquid is important in the flow rate management of the transported solids and the evaluation of stirring efficiency.

[0003] From the viewpoints of collision with solid substances and hygiene, it is desired to perform measurement without contact with the fluid. Patent Document 1 discloses a method for measuring the size (dimension) of solids flowing in a fluid using an optical camera.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using an optical camera, the fluid needs to be transparent. However, it is desired to measure the size of solids in an opaque fluid.

[0006] The present disclosure describes a measuring device and a measuring method capable of measuring the size of solids even in an opaque fluid.

Means for Solving the Problems

[0007] A measuring device according to an aspect of the present disclosure is a device for measuring solids in a fluid. This measuring device includes a transmitting transducer that transmits an ultrasonic signal, a receiving transducer that is provided facing the transmitting transducer through the fluid and receives a transmitted signal that has passed through the fluid among the ultrasonic signals, and a signal processing device that calculates the length of the solid along the propagation path of the ultrasonic signal based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer.

[0008] A measuring method according to another aspect of the present disclosure is a method for measuring solids in a fluid. This measuring method includes a step of transmitting an ultrasonic signal into the fluid from a transmitting transducer toward a receiving transducer, a step of receiving, by the receiving transducer, a transmitted signal that has passed through the fluid among the ultrasonic signals, and a step of calculating the length of the solid along the propagation path of the ultrasonic signal based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer.

[0009] In the above measuring device and measuring method, by simply measuring the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer, the length of the solid along the propagation path of the ultrasonic signal can be calculated. Therefore, it is possible to measure the size of the solid even in an opaque fluid.

[0010] The receiving transducer may be a probe. In this case, the configuration of the receiving transducer can be simplified.

[0011] The receiving transducer may include a light source that outputs a laser beam and a light receiving element that receives the laser beam. The light receiving element may detect the transmitted signal based on a change in the amount of light received when the transmitted signal passes between the light source and the light receiving element. In this case, the spot diameter of the laser beam corresponds to the reception surface of the transmitted signal. Therefore, it is possible to improve the measurement accuracy of the length of the solid.

[0012] The signal processing device may compare the signal intensity of the peak of the transmitted signal with a threshold, and if the signal intensity is less than the threshold, it may determine that no solid is present in the propagation path through the fluid. In this case, the possibility of falsely detecting noise as a transmitted signal is reduced. Therefore, it becomes possible to improve the accuracy of measuring the length of the solid.

[0013] The signal processing device may determine whether the peak is spike noise or not, and if it is determined that the peak is not spike noise, it may calculate the length of the solid. In this case, the possibility of falsely detecting spike noise as a peak in the transmitted signal is reduced. Therefore, it becomes possible to improve the measurement accuracy of the length of the solid.

[0014] The signal processing device may calculate the position of a solid in a fluid based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the reflected signal of the ultrasonic signal reflected by a solid is received by the transmitting transducer. In this case, the position of the solid in the fluid can be calculated simply by measuring the time from when the ultrasonic signal is transmitted from the transmitting transducer until the reflected signal of the ultrasonic signal reflected by a solid is received by the transmitting transducer. Therefore, it becomes possible to measure the position of a solid even in an opaque fluid.

[0015] The transmitting transducer may be a first transmitting transducer that transmits a first ultrasonic signal, and the receiving transducer may be a first receiving transducer provided opposite the first transmitting transducer via a fluid and receiving a first transmitted signal of the first ultrasonic signal that has passed through the fluid. The measuring device may further include a second transmitting transducer that transmits a second ultrasonic signal, and a second receiving transducer provided opposite the second transmitting transducer via a fluid and receiving a second transmitted signal of the second ultrasonic signal that has passed through the fluid. The second transmitting transducer and the second receiving transducer may be provided downstream of the first transducer and the first receiving transducer in the fluid. The signal processing device may calculate the velocity of the solid based on the time difference between the time the first transmitted signal was received by the first receiving transducer and the time the second transmitted signal was received by the second receiving transducer. In this case, the velocity of the solid can be calculated simply by measuring the time difference between the time the first transmitted signal was received by the first receiving transducer and the time the second transmitted signal was received by the second receiving transducer. Therefore, it becomes possible to measure the velocity of a solid even in an opaque fluid. [Effects of the Invention]

[0016] According to each aspect and embodiment of this disclosure, the size of a solid can be measured even in an opaque fluid. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic diagram showing a measuring device according to one embodiment. [Figure 2] Figure 2 is a diagram illustrating the measurement principle of the measuring device shown in Figure 1. [Figure 3] Figure 3 is a flowchart showing the measurement method performed by the measuring device shown in Figure 1. [Figure 4] Figure 4 is a schematic diagram showing the experimental setup used to verify the measuring device shown in Figure 1. [Figure 5]Figure 5 shows the measurement results obtained using the experimental apparatus shown in Figure 4. [Figure 6] Figure 6 shows a histogram of the solid size detected in the experimental apparatus shown in Figure 4. [Figure 7] Figure 7 is a diagram illustrating the measurement of the position of a solid object using the measuring device shown in Figure 1. [Figure 8] Figure 8 shows an example of a reflected signal. [Figure 9] Figure 9 is a diagram illustrating the measurement of solid velocity using the measuring device shown in Figure 1. [Figure 10] Figure 10 shows an example of the detection time difference. [Figure 11] Figure 11 is a diagram illustrating the method for determining the detection time difference. [Figure 12] Figure 12 is a schematic diagram illustrating another example of a receiving transducer. [Figure 13] Figure 13 is a diagram illustrating an example of calculating the length of a solid using the receiving transducer shown in Figure 1. [Figure 14] Figure 14 is a diagram illustrating an example of calculating the length of a solid using the receiving transducer shown in Figure 12. [Modes for carrying out the invention]

[0018] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0019] A measuring device according to one embodiment will be described with reference to Figure 1. Figure 1 is a schematic diagram showing a measuring device according to one embodiment. The measuring device 1 shown in Figure 1 is a device for measuring solid S in a fluid L. The fluid L may be a transparent fluid or an opaque fluid. The measuring device 1 measures the length d of the solid S. sThe measurement device measures the solid S in the fluid L flowing through the pipe 2. The measurement device 1 includes a transmitting transducer 11, a receiving transducer 12, a pulser receiver 13, and a signal processing device 14.

[0020] The transmitting transducer 11 functions as a transmitting unit that transmits an ultrasonic signal. The receiving transducer 12 functions as a receiving unit that receives the transmitted signal s(τ) that has passed through the fluid L from the ultrasonic signal transmitted from the transmitting transducer 11. The transmitting transducer 11 and the receiving transducer 12 are probes. The transmitting transducer 11 and the receiving transducer 12 are arranged to face each other with the fluid L in between. In this embodiment, the transmitting transducer 11 and the receiving transducer 12 are arranged on either side of the pipe 2, and each of the transmitting transducer 11 and the receiving transducer 12 is in contact with the wall of the pipe 2. An ultrasonic signal propagation path P is formed between the transmitting transducer 11 and the receiving transducer 12.

[0021] The pulse receiver 13 is connected to the transmit transducer 11 and the receive transducer 12. The pulse receiver 13 includes a generation circuit for generating an ultrasonic signal, an echo amplifier, a filter circuit, and an A / D conversion circuit. The pulse receiver 13 generates an ultrasonic signal and supplies the ultrasonic signal to the transmit transducer 11. In this embodiment, an ultrasonic pulse signal is used as the ultrasonic signal. The pulse receiver 13 receives the transmitted signal s(τ) received by the receive transducer 12. The pulse receiver 13 amplifies the transmitted signal s(τ), filters the amplified signal, and then performs A / D conversion to convert it from an analog signal to a digital signal, and transmits the digital signal to the signal processing device 14.

[0022] The signal processing device 14 is a device that processes signals. The signal processing device 14 is configured as a computer including, for example, a processor such as a CPU (Central Processing Unit), a memory such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and a communication device such as a network card. The signal processing device 14 calculates the length d of the solid S based on the time from when an ultrasonic signal is transmitted from the transmission transducer 11 until the transmission signal s(τ) is received by the reception transducer 12. s is calculated.

[0023] Next, the measurement principle of the measuring device 1 will be described while referring to FIGS. 1 and 2. FIG. 2 is a diagram for explaining the measurement principle of the measuring device shown in FIG. 1.

[0024] As shown in FIG. 1, the pipe 2 is a circular pipe with an inner diameter D and has a wall portion with a thickness d. w Here, as shown in FIG. 2, when no solid S exists on the propagation path P in the pipe 2 (that is, when only the fluid L is present), the propagation time τ0 is expressed by Equation (1) using the sound speed c in the wall portion of the pipe 2 and the sound speed c in the fluid L. The propagation time is the time from when an ultrasonic signal is transmitted from the transmission transducer 11 until the transmission signal s(τ) is received by the reception transducer 12. w and the sound speed c in the fluid L l are used.

Equation

[0025] When a solid S exists on the propagation path P in the pipe 2, the propagation time τ s is expressed by Equation (2) using the propagation time τ0, the sound speed c l , the length d of the solid S along the propagation path P s , and the sound speed c in the solid S s (the longitudinal wave sound speed). That is, due to the difference between the sound speed c l and the sound speed c s , the propagation time τ s corresponds to the length ds It changes.

number

[0026] By rearranging equation (2), we obtain equation (3).

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[0027] The propagation time τ0 is measured in advance and stored in memory (not shown). The speed of sound c l and the speed of sound c s These are all known and stored in memory. Therefore, the propagation time τ s By simply measuring the length d, s This is calculated.

[0028] Next, the measurement method performed by the measuring device 1 will be explained with reference to Figure 3. Figure 3 is a flowchart showing the measurement method performed by the measuring device shown in Figure 1. The series of processes shown in Figure 3 are started, for example, when the user of the measuring device 1 performs a measurement start operation in the signal processing device 14. At this time, the time step n is set to its initial value of 1. The transmitting transducer 11 and the receiving transducer 12 are positioned to contact the wall of the pipe 2 through which the fluid L to be measured flows, and to clamp the pipe 2.

[0029] As shown in Figure 3, first, the pulse receiver 13 generates an ultrasonic pulse signal and transmits the ultrasonic pulse signal from the transmitting transducer 11 to the receiving transducer 12 (step ST1). As a result, the ultrasonic pulse signal at time step n propagates along the propagation path P, and the signal that has passed through the fluid L of the ultrasonic pulse signal is transmitted to the receiving transducer 12 as a transmitted signal s(τ).

[0030] Then, the receiving transducer 12 receives the transmitted signal s(τ) at time step n (step ST2). The transmitted signal s(τ) received by the receiving transducer 12 is transmitted to the pulse receiver 13, where it is amplified. In the pulse receiver 13, the amplified signal is filtered, converted from an analog signal to a digital signal, and transmitted to the signal processing device 14.

[0031] Next, when the signal processing device 14 receives the transmitted digital signal s(τ), it performs a Hilbert transform on the transmitted signal s(τ) (step ST3). Then, the signal processing device 14 obtains an envelope from the signal obtained by the Hilbert transform (step ST4), and detects the peak of the transmitted signal s(τ) from the envelope (step ST5). In step ST5, the signal processing device 14 detects the peak in the time interval from when the ultrasonic pulse signal is transmitted from the transmitting transducer 11 until the propagation time τ0 has elapsed. Note that the Hilbert transform, the method for calculating the envelope, and the method for detecting the peak are all well known, so a detailed explanation is omitted.

[0032] Next, the signal processing device 14 compares the signal intensity of the peak of the transmitted signal s(τ) with a threshold value and determines whether the signal intensity is greater than or less than the threshold value (step ST6). The threshold value is set to a value that can distinguish between the peak of the transmitted signal s(τ) and noise. If, in step ST6, it is determined that the signal intensity is less than the threshold value (step ST6: NO), it can be said that the transmitted signal s(τ) did not reach the receiving transducer 12 during the time interval until the propagation time τ0 has elapsed. Therefore, the signal processing device 14 determines that there is no solid S on the propagation path P inside the pipe 2 (in the fluid L) and ends the measurement in time step n.

[0033] On the other hand, if it is determined in step ST6 that the signal strength is above a threshold (step ST6: YES), the signal processing device 14 determines whether the peak is spike noise or not (step ST7). In step ST7, the signal processing device 14 determines whether the peak is spike noise or not by determining, for example, whether the transmitted signal s(τ) has a signal strength that exceeds the threshold for a predetermined time or longer before and after the peak. Specifically, the signal processing device 14 determines that the peak is spike noise if the transmitted signal s(τ) does not have a signal strength that exceeds the threshold for a predetermined time or longer before and after the peak. On the other hand, the signal processing device 14 determines that the peak is not spike noise if the transmitted signal s(τ) has a signal strength that exceeds the threshold for a predetermined time or longer before and after the peak.

[0034] If the peak is determined to be spike noise in step ST7 (step ST7: YES), it can be said that the transmitted signal s(τ) did not reach the receiving transducer 12 during the time interval until the propagation time τ0 has elapsed. Therefore, the signal processing device 14 determines that there is no solid S on the propagation path P inside the pipe 2 (in the fluid L), and ends the measurement in time step n.

[0035] On the other hand, if it is determined in step ST7 that the peak is not spike noise (step ST7: NO), then it can be said that the transmitted signal s(τ) reached the receiving transducer 12 during the time interval until the propagation time τ0 has elapsed. In this case, the signal processing device 14 determines the propagation time τ s The signal processor detects the rise time (step ST8). In step ST8, the signal processor 14 determines, for example, the position where the signal intensity is 90% lower than the peak signal intensity, prior to the envelope peak, as the rising edge position of the transmitted signal s(τ). At the rising edge position of the transmitted signal s(τ), it can be considered that the transmitted signal s(τ) has reached the receiving transducer 12. For this reason, the signal processor 14 defines the time from when the ultrasonic signal is transmitted from the transmitting transducer 11 to the rising edge position of the transmitted signal s(τ) as the propagation time τ.s It is detected as such.

[0036] Next, the signal processing device 14 determines the length d of the solid S. s The length d is calculated (step ST9). In step ST9, the signal processing device 14 uses equation (3) to calculate the length d s The signal processing device 14 calculates the length d. s This may be displayed on a display (not shown) or recorded in memory (not shown). With this, the signal processing device 14 completes the measurement at time step n.

[0037] Next, it is determined whether the measurement termination conditions have been met (step ST10). Measurement termination conditions include, for example, the completion of a predetermined number of time steps, or the user performing an operation to terminate the measurement. Note that if it is determined in step ST6 that the signal strength is less than the threshold (step ST6: NO), and if it is determined in step ST7 that the peak is spike noise (step ST7: YES), the measurement at time step n is also terminated, and the determination in step ST10 is performed.

[0038] If it is determined in step ST10 that the measurement termination condition is not met (step ST10: NO), the time step n is incremented (step ST11), and the next time step n = n + 1 measurement is performed. In other words, the process returns to step ST1, and the process shown in Figure 3 is performed again. On the other hand, if it is determined in step ST10 that the measurement termination condition is met (step ST10: YES), the series of processes of the measurement method are terminated.

[0039] Note that at least one of steps ST6 and ST7 may be omitted.

[0040] Next, we will explain specific examples of measurements using the measuring device 1 with reference to Figures 4 to 6. Figure 4 is a schematic diagram of the experimental apparatus for verifying the measuring device shown in Figure 1. Figure 5 is a diagram showing the measurement results in the experimental apparatus shown in Figure 4. Figure 6 is a diagram showing the histogram of the solid size detected in the experimental apparatus shown in Figure 4.

[0041] As shown in Figure 4, the experimental apparatus 50 includes a water tank 51, a submersible pump 52, and an acrylic cylinder 53. The cylinder 53 is bent into an upward-convex U-shape, with one end connected to the submersible pump 52 and the other end placed in the water tank 51. The inner diameter of the cylinder 53 is 54 mm. Water is stored in the water tank 51 as the fluid L, and the water contains several spheres 54 as the solid S. The water containing the spheres 54 is pumped up by the submersible pump 52, flows through the cylinder 53, and returns to the water tank 51. Each sphere 54 is a polypropylene sphere with a diameter of 9.5 mm. The ultrasonic transmittance of polypropylene is approximately 78%. The specific gravity of each sphere 54 is 0.91 g / cm³. 3 The longitudinal wave speed of sound is approximately 2500 m / s.

[0042] A transmitting transducer 11 and a receiving transducer 12 were positioned on either side of the portion of the cylinder 53 where the water rises, and an ultrasonic pulse signal with a frequency of 4 MHz was transmitted from the transmitting transducer 11 at time intervals of 0.5 milliseconds. The water temperature during the verification was 10°C, and the water flow rate was approximately 230 L / min. At this time, the upward velocity of the sphere 54 was approximately 1.3 m / sec. The size (length d) of the sphere 54 flowing inside the cylinder 53 was measured by the measuring device 1. s The size (length d) of the sphere 54 detected over approximately 5 milliseconds was measured in real time. As shown in Figure 5, the size (length d) of the sphere 54 was measured over approximately 5 milliseconds. s The length was approximately 9.5 mm.

[0043] Measurements were taken continuously for approximately 50 seconds. During that time, the size (length d) of the sphere 54 was detected. sThe histogram of ) is shown in Figure 6. As shown in Figure 6, a peak appeared at the diameter of sphere 54. From these results, according to the measuring device 1, the dominant size (length d) of the solid S flowing in the pipe is s It can be seen that it is possible to identify ).

[0044] In the measurement device 1 and measurement method described above, only the time (propagation time) from when the ultrasonic signal is transmitted from the transmitting transducer 11 until the transmitted signal s(τ) is received by the receiving transducer 12 is measured, and the length d of the solid S along the propagation path P is measured. s The size (length d) of the solid S can be calculated (measured) in the measuring device 1 and the above measuring method, since they are acoustic methods, they do not depend on the shape of the flow path (pipe 2), and can be measured even in an opaque fluid L. s ) can be measured. In the measuring device 1, the transmitting transducer 11 and the receiving transducer 12 are provided facing each other via a fluid L. Therefore, the length d of the solid S can be measured non-invasively without contact with the fluid L. s It can measure this in real time.

[0045] A probe is used as the receiving transducer 12. Therefore, the configuration of the receiving transducer 12 can be simplified.

[0046] The receiving transducer 12 may receive noise. In this case, if the noise is mistakenly detected as a transmitted signal s(τ), the length d of the solid S will be affected. s There is a risk that the measurement may not be accurate. To address this problem, the signal processing device 14 compares the signal intensity of the peak of the transmitted signal s(τ) with a threshold, and determines that no solid exists on the propagation path P in the fluid L if the signal intensity is less than the threshold. With this configuration, the possibility of misdetecting noise as the transmitted signal s(τ) is reduced. Therefore, the length d of the solid S s This makes it possible to improve the measurement accuracy.

[0047] Spike noise with a signal intensity greater than the threshold may occur. When such spike noise is received by the receiving transducer 12, the spike noise is mistakenly detected as a peak in the transmitted signal s(τ), and the length d of the solid S is affected. s There is a risk that the measurement may not be accurate. To address this problem, the signal processing device 14 determines whether the peak of the transmitted signal s(τ) is spike noise or not, and if it is determined that the peak is not spike noise, the length d of the solid S s This is calculated. With this configuration, the possibility of falsely detecting spike noise as a peak in the transmitted signal s(τ) is reduced. Therefore, the length d of the solid S is calculated. s This makes it possible to improve the measurement accuracy.

[0048] The measuring device and measuring method relating to this disclosure are not limited to the embodiments described above.

[0049] For example, the measuring device 1 may measure the position of a solid S in a fluid L. The measurement of the position of the solid S by the measuring device 1 will be explained with reference to Figures 7 and 8. Figure 7 is a diagram illustrating the measurement of the position of a solid by the measuring device shown in Figure 1. Figure 8 is a diagram showing an example of a reflected signal.

[0050] As shown in Figures 7 and 8, when a solid S is present on the propagation path P in the fluid L, a portion of the ultrasonic signal transmitted from the transmitting transducer 11 is reflected by the solid S and received by the transmitting transducer 11 as a reflected signal r(τ). The signal processing device 14 processes the time τ from when the ultrasonic signal is transmitted from the transmitting transducer 11 until the reflected signal r(τ) is received by the transmitting transducer 11. r Based on this, the position x of the solid S in the fluid L s Calculate the position x s This is the distance from the inner surface of the wall of the pipe 2 where the transmitting transducer 11 is located to the solid S.

[0051] position x s is time τ r , thickness d w , speed of sound cw , and the speed of sound c l Using this, it is expressed by equation (4). Therefore, the signal processing device 14 uses equation (4) to determine the position x s Calculate.

number

[0052] In this case, the time τ is the time from when the ultrasonic signal is transmitted from the transmitting transducer 11 until the reflected signal r(τ) of the ultrasonic signal reflected by the solid S is received by the transmitting transducer 11. r By simply measuring the position x of the solid S in the fluid L, s It is possible to calculate (measure) the position x of the solid S even in an opaque fluid L. s It becomes possible to measure this.

[0053] The measuring device 1 may measure the velocity of a solid S in a fluid L. The measurement of the velocity of solid S by the measuring device 1 will be explained with reference to Figures 9 to 11. Figure 9 is a diagram illustrating the measurement of the velocity of a solid by the measuring device shown in Figure 1. Figure 10 is a diagram illustrating an example of the detection time difference. Figure 11 is a diagram illustrating the method for determining the detection time difference.

[0054] As shown in Figure 9, the measuring device 1 includes two sets of transducers. Specifically, the measuring device 1 includes a transmitting transducer 11a (first transmitting transducer), a transmitting transducer 11b (second transmitting transducer), a receiving transducer 12a (first receiving transducer), and a receiving transducer 12b (second receiving transducer).

[0055] The transmitting transducer 11a and the receiving transducer 12a are arranged facing each other via a fluid L. In this embodiment, the transmitting transducer 11a and the receiving transducer 12a are arranged on either side of a pipe 2, and each of the transmitting transducer 11a and the receiving transducer 12a is in contact with the wall of the pipe 2. The transmitting transducer 11a transmits an ultrasonic signal (first ultrasonic signal), and the receiving transducer 12a receives the transmitted signal sa(τ) (first transmitted signal) that has passed through the fluid L from the ultrasonic signal transmitted from the transmitting transducer 11a. As a result, an ultrasonic signal propagation path Pa is formed between the transmitting transducer 11a and the receiving transducer 12a.

[0056] The transmitting transducer 11b and the receiving transducer 12b are arranged facing each other across a fluid L. In this embodiment, the transmitting transducer 11b and the receiving transducer 12b are arranged on either side of a pipe 2, and each of the transmitting transducer 11b and the receiving transducer 12b is in contact with the wall of the pipe 2. The pair of transmitting transducer 11b and the receiving transducer 12b is located downstream of the pair of transmitting transducer 11a and the receiving transducer 12a across the fluid L. The transmitting transducer 11b transmits an ultrasonic signal (second ultrasonic signal), and the receiving transducer 12b receives the transmitted signal sb(τ) (second transmitted signal) that has passed through the fluid L from the ultrasonic signal transmitted from the transmitting transducer 11b. As a result, an ultrasonic signal propagation path Pb is formed between the transmitting transducer 11b and the receiving transducer 12b.

[0057] In this case, as shown in Figure 10, the transmitted signal sa(τ) that has passed through the fluid L from the transmitting transducer 11a is received by the receiving transducer 12a, and then the transmitted signal sb(τ) that has passed through the fluid L from the transmitting transducer 11b is received by the receiving transducer 12b.

[0058] The signal processing device 14 calculates the velocity v of the solid S based on the time difference Δt between the time when the transmitted signal sa(τ) was received by the receiving transducer 12a and the time when the transmitted signal sb(τ) was received by the receiving transducer 12b. s The signal processing device 14 calculates the velocity v by dividing the distance ΔL by the time difference Δt, as shown in equation (5). s The following is calculated: Distance ΔL is the distance (center-to-center distance) between the set of transmitting transducer 11a and receiving transducer 12a and the set of transmitting transducer 11b and receiving transducer 12b. In other words, distance ΔL is the distance (center-to-center distance) between propagation path Pa and propagation path Pb.

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[0059] As shown in Figure 11, the signal processing device 14 may determine the time difference Δt by using the cross-correlation function between the transmitted signal sa(τ) and the transmitted signal sb(τ). Specifically, the signal processing device 14 defines the time difference Δt as the time difference when the cross-correlation coefficient R(Δt) is at its maximum value max(R). The time difference Δt is expressed as arg max(R).

[0060] In this case, by simply measuring the time difference Δt between the time when the transmitted signal sa(τ) is received by the receiving transducer 12a and the time when the transmitted signal sb(τ) is received by the receiving transducer 12b, the velocity v of the solid S can be determined. s It is possible to calculate (measure) the velocity v of the solid S even in an opaque fluid L. s It becomes possible to measure this.

[0061] The measuring device 1 may include a receiving transducer 15 as shown in Figure 12 instead of the receiving transducer 12. The receiving transducer 15 includes a light source 16 and a photodetector 17. The light source 16 is a device that outputs laser light. The light source 16 includes a semiconductor laser that outputs laser light, an optical fiber that propagates the laser light, a fiber coupler provided at one end of the optical fiber that receives the laser light output from the semiconductor laser, and a collimator provided at the other end of the optical fiber that converts the laser light into parallel light and outputs it toward the photodetector 17.

[0062] The photodetector 17 is an optical component that receives laser light. The photodetector 17 is also called a photodetector. The receiving transducer 15 may further include an optical fiber that receives laser light output from the light source 16 and guides it to the photodetector 17. The photodetector 17 detects the transmitted signal s(τ) by the change in the amount of light received caused by the transmitted signal s(τ) passing through the optical path between the light source 16 and the photodetector 17.

[0063] Specifically, the laser light is deflected by a local refractive index gradient that occurs when the transmitted signal s(τ) passes through the optical path between the light source 16 and the photodetector 17. The deflection angle θ of the laser light is expressed by equation (6), using the density gradient δn due to the transmitted signal s(τ), and the width W and wavelength Λ of the transmitted signal s(τ). Therefore, the amount of laser light received by the photodetector 17 changes according to the deflection angle θ.

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[0064] As shown in Figure 13, when the receiving transducer 12 is used, the receiving surface of the transmitted signal s(τ) is wide. This receiving surface usually has a diameter of 10 mm or more. Therefore, the length d of the solid S is wide from all the transmitted signal that has passed through the solid S. s This is calculated. In the example shown in Figure 13, the length d s Since it is calculated as the average of lengths d1, d2, d3, d4, and d5, the actual length d sIt will become smaller than that.

[0065] On the other hand, as shown in Figure 14, when the receiving transducer 15 is used, the spot diameter of the laser beam corresponds to the receiving surface of the transmitted signal s(τ). The spot diameter is, for example, about 100 μm to 1 mm. Therefore, only a portion of the transmitted signal that has passed through the solid S is received, and the length d of the solid S is also received. s This makes it possible to improve the measurement accuracy.

[0066] (Note) [Clause 1] A measuring device for measuring solids in a fluid, A transmitting transducer that transmits ultrasonic signals, A receiving transducer is provided opposite the transmitting transducer via the fluid and receives the transmitted signal of the ultrasonic signal that has passed through the fluid, A signal processing device that calculates the length of a solid along the propagation path of the ultrasonic signal based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer, A measuring device equipped with the following features.

[0067] [Clause 2] The receiving transducer is a probe, as described in Clause 1 of the measuring device.

[0068] [Clause 3] The receiving transducer includes a light source that outputs laser light and a photodetector that receives the laser light. The measuring device according to Clause 1, wherein the light-receiving element detects the transmitted signal by a change in the amount of light received caused by the transmitted signal passing between the light source and the light-receiving element.

[0069] [Clause 4] The signal processing device compares the signal intensity of the peak of the transmitted signal with a threshold, and determines that no solid exists on the propagation path in the fluid when the signal intensity is less than the threshold, according to any one of the provisions 1 to 3.

[0070] [Clause 5] The signal processing device determines whether the peak is spike noise, and if it is determined that the peak is not spike noise, it calculates the length of the solid, as described in Clause 4.

[0071] [Clause 6] The signal processing device is a measuring device according to any one of Clauses 1 to 5, which calculates the position of the solid in the fluid based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the reflected signal of the ultrasonic signal reflected by the solid is received by the transmitting transducer.

[0072] [Clause 7] The transmitting transducer is a first transmitting transducer that transmits a first ultrasonic signal, The receiving transducer is provided facing the first transmitting transducer across the fluid, and is a first receiving transducer that receives the first transmitted signal of the first ultrasonic signal that has passed through the fluid. The aforementioned measuring device is A second transmitting transducer that transmits a second ultrasonic signal, A second receiving transducer is provided facing the second transmitting transducer via the fluid and receives the second transmitted signal of the second ultrasonic signal that has passed through the fluid, Furthermore, The second transmitting transducer and the second receiving transducer are provided downstream of the fluid from the first transmitting transducer and the first receiving transducer. The signal processing device is a measuring device according to any one of the clauses 1 to 6, which calculates the velocity of the solid based on the time difference between the time the first transmitted signal is received by the first receiving transducer and the time the second transmitted signal is received by the second receiving transducer.

[0073] [Clause 8] A measurement method for measuring solids in a fluid, The steps include transmitting an ultrasonic signal into a fluid from a transmitting transducer to a receiving transducer, The receiving transducer receives the transmitted signal from the ultrasonic signal that has passed through the fluid, A step of calculating the length of a solid along the propagation path of the ultrasonic signal based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer, Measurement methods, including those mentioned above. [Explanation of Symbols]

[0074] 1... Measuring device, 11... Transmitting transducer, 11a... Transmitting transducer (first transmitting transducer), 11b... Transmitting transducer (second transmitting transducer), 12... Receiving transducer, 12a... Receiving transducer (first receiving transducer), 12b... Receiving transducer (second receiving transducer), 14... Signal processing device, 15... Receiving transducer, 16... Light source, 17... Photodetector.

Claims

1. A measuring device for measuring solids in a fluid, A transmitting transducer that transmits ultrasonic signals, A receiving transducer is provided opposite the transmitting transducer via the fluid and receives the transmitted signal of the ultrasonic signal that has passed through the fluid, A signal processing device that calculates the length of a solid along the propagation path of the ultrasonic signal based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer, A measuring device equipped with the following features.

2. The measuring device according to claim 1, wherein the receiving transducer is a probe.

3. The receiving transducer includes a light source that outputs laser light and a photodetector that receives the laser light. The measuring device according to claim 1, wherein the light-receiving element detects the transmitted signal by a change in the amount of light received caused by the transmitted signal passing between the light source and the light-receiving element.

4. The measuring device according to any one of claims 1 to 3, wherein the signal processing device compares the signal intensity of the peak of the transmitted signal with a threshold, and determines that no solid exists on the propagation path in the fluid when the signal intensity is less than the threshold.

5. The measuring device according to claim 4, wherein the signal processing device determines whether the peak is spike noise, and if it is determined that the peak is not spike noise, it calculates the length of the solid.

6. The measuring device according to any one of claims 1 to 3, wherein the signal processing device calculates the position of the solid in the fluid based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the reflected signal of the ultrasonic signal reflected by the solid is received by the transmitting transducer.

7. The transmitting transducer is a first transmitting transducer that transmits a first ultrasonic signal, The receiving transducer is provided facing the first transmitting transducer across the fluid, and is a first receiving transducer that receives the first transmitted signal of the first ultrasonic signal that has passed through the fluid. The aforementioned measuring device is A second transmitting transducer that transmits a second ultrasonic signal, A second receiving transducer is provided facing the second transmitting transducer via the fluid and receives the second transmitted signal of the second ultrasonic signal that has passed through the fluid, Furthermore, The second transmitting transducer and the second receiving transducer are provided downstream of the fluid from the first transmitting transducer and the first receiving transducer. The measuring device according to any one of claims 1 to 3, wherein the signal processing device calculates the velocity of the solid based on the time difference between the time the first transmitted signal is received by the first receiving transducer and the time the second transmitted signal is received by the second receiving transducer.

8. A measurement method for measuring solids in a fluid, The steps include transmitting an ultrasonic signal into a fluid from a transmitting transducer to a receiving transducer, The receiving transducer receives the transmitted signal from the ultrasonic signal that has passed through the fluid, A step of calculating the length of a solid along the propagation path of the ultrasonic signal based on the time from when the ultrasonic signal is transmitted from the transmitting transducer until the transmitted signal is received by the receiving transducer, Measurement methods, including those mentioned above.

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