JP2002098637A - Concentration measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentration measuring apparatus which enables measurement with a higher sensitivity up to a higher concentration of turbid components while making the best of the advantage of a diffusive reflection type using a laser light emitting element with a higher selectivity of wavelength as light source. SOLUTION: In the concentration measuring apparatus which measures the concentration of turbid components in a liquid to be measured by detecting the diffusively reflected light of a laser light emitted into the liquid, an optical fiber for emitting laser light and an optical fiber for receiving the light are bundled respectively in plurality of form one sensor part thereby permitting measurement with a higher sensitivity up to a higher concentration of turbid components. A light emitting/receiving element is connected to the sensor surface with a number of flexible optical fibers to form a waveguide path therebetween. This makes possible the designing of the shape of the guide wave path, ultimately that of the sensor as a whole with a substantial freedom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures the concentration of turbid components in a liquid to be measured, such as the concentration of sludge in sewage generated from facilities such as sewage, drainage, and human waste treatment, and the concentration of solids in treated water. More particularly, the present invention relates to a concentration measuring device that measures the concentration of a turbid component by a diffuse reflection method using a laser beam.

[0002]

2. Description of the Related Art As a conventional method for measuring the concentration of a turbid component in a liquid to be measured, an ultrasonic system, an infrared system, a microwave system, a dry weight system, and the like are known. However, in each of these measurement methods, there is a problem that the output value becomes unstable except for the dry weight method when the properties of the turbid component to be measured change or its concentration fluctuates. If unstable concentration information is transmitted to and input to peripheral equipment or devices, there is a possibility that a monitoring system or a processing system may malfunction. In addition, the dry weight method has problems such as a long measurement time, a need to set drying conditions, and generation of waste after measurement.

On the other hand, as another method, there is known a transmitted light method of irradiating a liquid to be measured with a laser beam and detecting the amount of laser light transmitted through the liquid to be measured. However, in this measurement method, especially when the concentration of the turbid component is high (for example, 1).
% Or more, especially about 3% or more), it is difficult to optically measure the concentration with high sensitivity, and it is difficult to measure with high accuracy. This is because the color of the turbid component (for example, sludge) is often black or the like, and the light is often absorbed, so that the light is greatly attenuated and high-sensitivity measurement becomes difficult. It is.

[0004]

In order to solve the above-mentioned problems in the transmitted light system in the case of high concentration measurement,
It is considered that a method of detecting the reflected light of the laser light applied to the liquid to be measured is effective. This method is also called a diffuse reflection method because most of the laser light applied to the liquid to be measured impinges on a turbid component in the liquid to be measured and is diffused before being reflected. If the diffuse reflection light is detected in this manner, the influence of the color of the turbid component is less likely to be exerted, so that it is possible to measure even a liquid to be measured having a relatively high turbid component concentration.

However, in a conventional diffuse reflection type density measuring apparatus using a laser beam, as schematically shown in FIG. 10, for example, a light guide tip surface 101 for emitting a laser beam and a light receiving tip 101 for receiving a light in a density sensor section. Since the light guide tip surface 102 is formed relatively large (for example, about 3 mmφ), the optical light span L between the two becomes relatively large (for example, 5 m).
m), it is difficult to detect diffuse reflection light with a sufficient amount of light in a state of low attenuation, and it is difficult to optically increase measurement sensitivity.

An object of the present invention is to provide a high sensitivity to a high turbid component concentration (for example, to a concentration of 1% or more, especially to a concentration of 3% or more) while taking advantage of the diffuse reflection method using a laser beam. An object of the present invention is to provide a measurable concentration measuring device.

[0007]

In order to solve the above-mentioned problems, a concentration measuring apparatus according to the present invention provides a method for measuring the concentration of a turbid component in a liquid to be measured by a laser beam emitted toward the liquid to be measured. An apparatus for measuring by detecting diffuse reflection light of the above, characterized in that a plurality of optical fibers for emitting laser light and an optical fiber for receiving light are bundled in plural to constitute one sensor unit.

[0008] A relatively large number of light emitting optical fibers and light receiving optical fibers are bundled together. For example, a total of 100 or more optical fibers are bundled. The total number of optical fibers may be determined as appropriate according to the properties and concentration range of the turbid component in the liquid to be measured as the concentration measurement target, the fiber diameter of one optical fiber used, the size of the sensor surface, and the like. What is necessary is just to select from the range of about 50,000. The diameter of each optical fiber is
For example, it may be determined from the range of 20 to 80 μm. The diameter of the sensor surface is usually determined mechanically because the sensor part is usually attached to a pipe or the like, but may be appropriately determined, for example, from a range of about 3 to 15 mm. Once the diameter of each optical fiber and the size of the sensor surface are determined,
The maximum value of the number of optical fibers to be bundled is almost determined.

The arrangement of the light emitting optical fiber and the light receiving optical fiber to be bundled is particularly important on the sensor surface which directly receives and emits light. This arrangement can take various forms, but as shown in the examples described later, the characteristics are slightly different due to the concentration measurement obtained by the adopted arrangement form.

[0010] As a possible arrangement, for example, a light-emitting optical fiber and a light-receiving optical fiber are randomly arranged on the sensor surface of the sensor section. Since the output value of the received laser light, that is, the amount of received light, is the largest in the case of this random arrangement, this form is the most preferable. However, the present invention is not limited to this random arrangement, and a light-emitting optical fiber is arranged at the center of the sensor surface of the sensor unit, and a light-receiving optical fiber is arranged around the center. Where the optical fiber for light emission is arranged and the optical fiber for light emission is arranged around it, and in the sensor surface of the sensor section, the light emitting optical fiber is arranged on one half surface and the light receiving optical fiber is arranged on the other half surface Can also be adopted.

The laser beam supplied to the optical fiber for light emission may be a laser beam supplied continuously, but by using a laser beam driven by a pulse, the power consumption can be greatly reduced. become. Also,
As a laser light source, an ordinary light emitting diode (LE
Although it is possible to use D), it is more preferable to use a laser light emitting diode having a wavelength range suitable for laser light emission and having high intensity in the specific wavelength range. Compared to other light sources, such laser light-emitting diodes are compact, have a very strong light source, have a monochromatic light wavelength, and have high selectivity based on a certain wavelength. Performance can be ensured and the service life is long. In addition, when the pulse driving is performed, the setting and control of the frequency of the laser light emission can be easily and satisfactorily and accurately set and controlled to the target characteristics.

In the above-described density measuring apparatus according to the present invention, since it is assumed that the density is measured by the diffuse reflection method of the laser beam, the density measurement apparatus is less affected by the color of the turbid component than the transmitted light method. It can be measured with high sensitivity up to a relatively high concentration. A large number of optical fibers for emitting laser light and optical fibers for receiving light are bundled to form a single sensor unit. Amount and received light amount can be achieved. Further, since the individual optical fibers are thin, for example, the light span between the adjacent light emitting optical fibers and light receiving optical fibers on the sensor surface in the case of random arrangement becomes extremely small, and the optical sensitivity to density is greatly improved. As a result, it is possible to measure the concentration with high sensitivity and high accuracy from a low concentration to a high concentration of 1% or more, and further to a high concentration of 3% or more. It is possible to perform measurement with good accuracy and stability.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a concentration measuring apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows a basic configuration of a concentration measuring device according to an embodiment of the present invention, FIG. 2 shows an example of a case where the device is configured as a specific concentration sensor, and FIGS. 3 to 6 show respective arrangements of an optical fiber on a sensor surface. An example of each embodiment is shown.

In FIG. 1, reference numeral 1 denotes the entire concentration measuring device. The concentration measuring device 1 is configured in the form of a sensor, and is attached so that the tip thereof faces, for example, the inside of the pipe 2. The concentration measuring device 1 detects the diffuse reflection light 6 of the laser light 5 emitted toward the turbid component 4 (for example, sludge particles) in the liquid 3 to be measured flowing through the pipe 2, thereby detecting the liquid to be measured. The apparatus is configured as a diffuse reflection light type concentration measuring device for measuring the concentration of the turbid component 4 in 3.

In the present embodiment, a laser light emitting diode 7 (which may be abbreviated as a laser diode) that emits a high-intensity laser light in a specific wavelength range suitable for laser light emission is used as a laser light source. Laser light is emitted in a predetermined pulse form by pulse driving by a driving circuit 8 having an oscillator. The laser light emitted by the laser light emitting diode 7 is incident via the laser light diffusion plate 9 on the incident ends of a large number of light emitting optical fibers 11 bundled and held by the optical fiber fixing bracket 10. The laser light is applied to the incident end of the light emitting optical fiber 11 by the laser light diffusing plate 9 while being uniformly diffused.

A large number of light emitting optical fibers 11 and a substantially equal number of light receiving optical fibers 12 are bundled to form one sensor unit 13. Light emitting optical fiber 11 and light receiving optical fiber 1 bundled
For example, the optical fiber 2 is formed on the sensor surface 15 in a state where the relative position is fixed in the fixture 14, and the positions of the tip surfaces of the optical fibers are aligned. Sensor surface 1
5, the laser light guided through the light emitting optical fiber 11 is emitted from the emission end of the light emitting optical fiber 11 toward the liquid 3 to be measured, and hits the turbid component 4 in the liquid 3 to be measured. The diffused and reflected laser light is received at the incident end of the light receiving optical fiber 12. In the present embodiment, the reception and emission of the laser light on the sensor surface 15 are performed through a glass plate 16 provided on the sensor surface 15. The material of the glass plate 16 is not particularly limited, but sapphire glass which is hard and hard to be damaged, is chemically stable, has excellent acid resistance, alkali resistance, and solvent resistance and is thermally stable is preferable. It is preferable that the surface of the glass plate 16 on the side of the liquid 3 to be measured is mirror-finished, because dirt by sludge hardly adheres and scratches by sludge hardly occur. In addition,
Although shown in FIG. 1 as a flat glass plate 16, a lens having an appropriate focal length may be used instead of such a glass plate 16. As a lens,
A plano-convex lens or the like having a flat surface on the sensor surface side and a convex surface on the other surface and having a lens function is preferable.

The diffuse reflection light of the laser light received from the incident end of the light receiving optical fiber 12 is guided through the light receiving optical fiber 12, and is emitted from the emission end which is the opposite end. A large number of light receiving optical fibers 12 are held in a bundled state by the optical fiber fixing bracket 17 also at the end of the light receiving optical fiber 12 on the emission end side.

In this embodiment, the diffusely reflected light emitted from the light emitting end of the light receiving optical fiber 12 is received by a photodiode 19 as a reflected light receiving element through a visible light cut filter 18, and its light amount is detected. By disposing the visible light cut filter 18, the influence of disturbance light (for example, disturbance light from a fluorescent lamp or the like) on the density measurement can be suppressed. In this embodiment, the received light amount signal of the photodiode 19 is
By being amplified by 0, the signal is output as a signal having a magnitude suitable for concentration measurement.

FIG. 2 shows an example in which the density measuring device 1 having the above-described basic configuration is incorporated in the form of one density measuring sensor. In the concentration measuring sensor 21 shown in FIG.
1. A stabilized power supply 23 as a power supply for a sensor, a laser light emitting circuit 24 including a laser diode driving circuit and an optical feedback compensation circuit, a light receiving amplifier circuit 25 having the same function as the amplifier circuit 20 in FIG. 26 and a light receiving photodiode 27 are provided. In the present embodiment, a thermistor 28 for performing temperature compensation of the laser light emitting diode 26 is further provided. Input and output of signals are performed via a connector 29 provided at one end of the main body case 22.

A large number of light emitting optical fibers 30 for guiding the laser light from the laser light emitting diode 26 and a light receiving optical fiber 31 for guiding the received and reflected light to the photodiode 27 are arranged in an optical fiber protective tube 32 in a predetermined arrangement. The sensor is bundled, fixed and held, and is formed on the sensor surface with its tips aligned at the sensor tip 33 in a predetermined arrangement. The optical fiber protection tube 32 is formed in a straight tube in this embodiment, but since a large number of optical fibers bundled inside have flexibility, a bent tube or a longer length may be used as necessary. It is also possible to constitute a tube. The sensor tip portion 33 has a cap 34 that can be attached and detached with a screw, and the glass plate 16 as shown in FIG. 1 is attached to this portion. By using the screw cap method, it is possible to easily replace the screw cap if necessary (for example, when a glass plate or the like is damaged).
In addition, since the optical fiber may be distorted by vibration and change the light conductivity to cause noise, in order to prevent this, foam rubber (for example, foam silicon rubber) is formed on the optical fiber protection tube 32. The vibration of the optical fiber is prevented by filling. If the epoxy resin or the acrylic resin is filled and fixed in the optical fiber protective tube 32, the optical fiber is affected by the thermal expansion of the resin and causes a temperature drift. Therefore, as described above, the elasticity and the flexibility are high. It is preferable to retain the thermal expansion by a foamable rubber capable of absorbing the thermal expansion within its own volume range. At the sensor tip portion 33, a large number of ultrafine optical fibers are bundled in a multicore. In this portion, for example, a special epoxy resin having excellent heat resistance or the like is adhered and fixed to a fixture, and the tip surface is mirror-polished. Then, it may be formed on the sensor surface.

The arrangement of the light emitting optical fiber and the light receiving optical fiber on the sensor surface of the sensor section is shown in FIG.
Or various forms as shown in FIG. The arrangement shown in FIG. 3 is based on the light emitting optical fiber 42 (open circle) and the light receiving optical fiber 4 on the circular sensor surface 41.
3 (black circles) are randomly arranged, and are preferably arranged uniformly as shown in FIG. 3, that is, the light emitting optical fibers 42 and the light receiving optical fibers 43 are alternately adjacent to each other. preferable. This random arrangement form is most preferable from the viewpoint of the output characteristics and the magnitude of the output for the density measurement, as will be understood from experiments described later.

In the arrangement shown in FIG. 4, a light emitting optical fiber 42 is arranged at the center of a sensor surface 41, and a light receiving optical fiber 43 is arranged concentrically therearound. The arrangement form shown in FIG. 5 is such that a light receiving optical fiber 43 is arranged at the center of the sensor surface 41 and a light emitting optical fiber 42 is arranged concentrically around the central part. The arrangement shown in FIG.
The light emitting optical fiber 42 is arranged on one half surface, that is, one semicircular portion, and the light receiving optical fiber 43 is arranged on the other half surface, that is, the other semicircular portion. In any of the arrangements shown in FIG. 3 to FIG. 6, as shown in the experimental results described later, sufficiently excellent characteristics for concentration measurement aimed at in the present invention can be obtained.

FIGS. 3 to 6 are schematic diagrams, and the total number of optical fibers on the sensor surface is as follows.
The number is much larger than the one shown in the figure, and the total number is 1
The number is appropriately set within a range of about 00 to 50,000. Even if each optical fiber is an extra-fine optical fiber and the measurement is impossible due to the shortage of light with a single core, for example, 1500 optical fibers for light emission and 1500 optical fibers for light reception, about 3000 in total. By doing so, a sufficiently large light emission amount and light reception amount can be obtained.

The operation and effect of the concentration measuring apparatus according to the present invention having the above-described configuration will be described with reference to the configuration shown in FIG. A large number of light-emitting optical fibers 11 and light-receiving optical fibers 12 are bundled to form one sensor section 13, which is arranged in a predetermined form on the sensor surface 15. Even if is small, a large amount of light and light can be obtained as a whole by bundling a large number. As a result, light emission,
Insufficient light quantity is avoided in both light reception and light quantity necessary and sufficient for obtaining high sensitivity can be obtained. More specifically, a sufficient quantity of light can be obtained by setting the number to 100 to 50,000, particularly 1000 or more, and more preferably about 3000 in total.

Further, since the light emitting optical fiber 11 and the light receiving optical fiber 12 bundled in a large number are each made of an extremely fine optical fiber, the light span in the density measurement can be reduced to the limit. For example, in the case of the random arrangement shown in FIG. 3, when the diameter of the optical fiber is 30 μm, for example, FIG.
As shown in FIG.
The light span L between the light receiving optical fiber 52 and the
m, and an extremely small light span can be obtained.
As a result, the ratio of the light span is actually 30: 5000 = 1: 167, as compared with the form having a light span of about 5 mm as shown in FIG. That is, a sensitivity as high as 167 times as high as the sensitivity for density measurement is obtained. As a result, the sensitivity is greatly increased, so that not only when the concentration of the turbid component is low, but also
%, Particularly high concentrations exceeding 3%, and even higher concentrations exceeding 5%. In addition, since it has high sensitivity, it can favorably follow changes in the properties and concentration of the turbid component, and stable and accurate concentration measurement can be performed.

As a light source of the laser beam, a usual L
Since a laser light emitting diode 7 that emits high-intensity laser light in a specific wavelength range is used instead of the ED, sufficient intensity can be obtained as a light source compared to other light sources, and excellent reproducibility is obtained. In addition to this, excellent pulse drive characteristics can be obtained in which a target frequency characteristic can be accurately obtained in pulse driving and a desired light emission can be sharply performed.

The pulse driving of the laser beam is performed, for example, as shown in FIG.
Is controlled as shown in FIG. In the illustrated example, the driving is performed with a pulse of 2 msec, and the pulse interval is set to 150 msec. Therefore, the duty ratio is 1:75,
Power consumption is 1.33% as compared with the case of continuous lighting, and power saving is achieved. However, the example shown in FIG. 8 is merely an example, and these pulse widths, pulse intervals, and duty ratios can be freely set according to the target pulse drive characteristics.

If the laser light emitting diode 7 is controlled in combination with the pulse light feedback method, the laser pulse light can be stabilized. In the case of a semiconductor laser diode, the light intensity greatly fluctuates with respect to temperature fluctuations in the outer environment, so that temperature compensation must be performed. Light emission becomes possible. However, in the case of aiming for further stabilization, if the compensation is insufficient with only the optical feedback system, the temperature may be compensated by a thermistor or the like.

As described above, in the concentration measuring apparatus according to the present invention, extremely high sensitivity can be realized, and from the low concentration region to the high concentration region exceeding 1%, and further from the high concentration region exceeding 3%, the concentration of the liquid to be measured is increased. It becomes possible to measure the concentration of the turbid component with high accuracy.

The following experiment was conducted to examine the performance of the concentration measuring apparatus according to the present invention. Using an apparatus equivalent to that shown in FIG. 2, the arrangement of the optical fibers on the sensor surface was set to each of the various forms shown in FIGS. 3 to 6, and pseudo-sludge was contained as the liquid to be measured, and its concentration was adjusted. Using the samples adjusted to various concentrations, characteristics in the concentration measurement (output [output voltage] characteristics corresponding to the measured concentrations) were examined. In the present experiment, yeast cells were used as the pseudo-sludge, but the pseudo-sludge is not limited to this, and formazin, solka floc, kaolin and the like can also be used. The sensor surface had an outer diameter of 10 mmφ, and a sapphire glass flat plate having a thickness of 1 mm was attached on the sensor surface for measurement. The results are shown in Table 1 and FIG. In Table 1 and FIG. 9, "random" indicates the arrangement shown in FIG. 3, "double circle (center light)" indicates the arrangement shown in FIG. 4, and "double circle (outer circle light)" indicates the figure. The arrangement form shown in FIG. 5 and the “half circle” respectively correspond to the arrangement form shown in FIG. The output data in Table 1 and FIG. 9 are represented by the ratio to the full scale after the output amplifier circuit (the ratio when the full scale is set to 100% is represented by%).
Shows the relationship between the output and the pseudo-sludge concentration (%).

[0031]

[Table 1]

As shown in Table 1 and FIG. 9, all of the arrangements have sufficient linearity required for high-precision measurement from low to high concentration, and can be measured at high concentration. It has been demonstrated that the device can be sufficiently used as a possible concentration measuring device. In particular, in the case of a random arrangement, high output is obtained, and linearity characteristics that can be measured up to higher concentrations are obtained, and extremely excellent characteristics for high-density measurement that cannot be realized with the conventional device are obtained. Was done.

In the above experiment, a glass plate was mounted on the sensor surface. However, as described above, a plano-convex lens having a certain focal length can be used instead of the glass plate. Excellent characteristics equivalent to the characteristics shown in FIG. 9 are obtained.

[0034]

As described above, according to the concentration measuring apparatus of the present invention, while taking advantage of the advantage of the diffuse reflection method of laser light, that is, the advantage of being less affected by the color of the turbid component, From low concentration to high concentration of 1% or more, and even high concentration of 3% or more, the concentration can be measured with extremely high sensitivity and high accuracy. In addition, as a result of high-sensitivity measurement, fluctuations in the properties and concentration of the turbid component can be satisfactorily followed, and stable concentration measurement over a long period of time becomes possible. Also,
Since the sensor surface and the light receiving / emitting element are connected by a large number of optical fibers, the shape between them can be set to a substantially free shape by utilizing the flexibility of the optical fiber, and easily according to the installation location. Optimal sensor shape can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a concentration measuring device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an example in which the device of FIG. 1 is configured in a sensor form.

FIG. 3 is a schematic configuration diagram of a sensor surface showing an arrangement form of an optical fiber according to the present invention.

FIG. 4 is a schematic configuration diagram of a sensor surface showing another arrangement form of the optical fiber according to the present invention.

FIG. 5 is a schematic configuration diagram of a sensor surface showing still another arrangement form of the optical fiber according to the present invention.

FIG. 6 is a schematic configuration diagram of a sensor surface showing still another arrangement form of the optical fiber according to the present invention.

FIG. 7 is an explanatory diagram showing a light span according to an example of the present invention.

FIG. 8 is an explanatory diagram illustrating an example of laser pulse driving according to the present invention.

FIG. 9 is an output characteristic diagram obtained in an experiment performed to confirm the effect of the present invention.

FIG. 10 is an explanatory diagram showing an example of a light span of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concentration measuring apparatus 2 Pipe 3 Liquid to be measured 4 Suspended component 5 Emitted laser light 6 Diffuse reflected light of laser light 7, 26 Laser light emitting diode 8 Laser light driving circuit 9 Laser light diffusion plate 10, 17 Optical fiber fixing bracket 11, 30 Optical fiber for light emission 12, 31 Optical fiber for light reception 13 Sensor part 14 Fixing bracket 15 Sensor surface 16 Glass plate 18 Visible light cut filter 19, 27 Photodiode 20 Amplifier circuit 21 Concentration measuring sensor 22 Main body case 23 Stabilized power supply 24 Laser Light emitting circuit 25 Light receiving and amplifying circuit 28 Thermistor 29 Connector 32 Optical fiber protection tube 33 Sensor tip 34 Cap 41 Sensor surface 42, 51 Light emitting optical fiber 43, 52 Light receiving optical fiber

 ──────────────────────────────────────────────────続 き Continued from the front page (71) Applicant 000006105 Meidensha Co., Ltd. 2-1-1-17 Osaki, Shinagawa-ku, Tokyo (71) Applicant 593117796 Automatic System Research Co., Ltd. 1-10-10 Iwamotocho, Chiyoda-ku, Tokyo No. 5 (71) Applicant 500444483 Shibaura System Co., Ltd. 5-32-7 Sendagaya, Shibuya-ku, Tokyo (71) Applicant 500444508 Yuzo Miyazawa 2-2-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Tokyo Metropolitan Sewerage Bureau (72) Inventor Toshiro Harada 2-6-2 Otemachi, Chiyoda-ku, Tokyo Inside Tokyo Sewerage Service Co., Ltd. (72) Inventor Tomoyuki Hayashi 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Invention Seihei Yano 3-9-2 Nihombashi, Chuo-ku, Tokyo Tomoe Industries Co., Ltd. (72) Inventor Shigeo Sato Higashi 2-1-1-17 Osaki, Shinagawa-ku, Kyoto Inside Meidensha Co., Ltd. (72) Inventor Tsuneo Imazu 1-10-5 Iwamotocho, Chiyoda-ku, Tokyo Inside Automatic System Research Co., Ltd. (72) Inventor Takahiro Sakai Tokyo 5-32-7 Sendagaya, Shibuya-ku, Tokyo Shibaura System Co., Ltd. (72) Inventor Yuzo Miyazawa 2-81-1, Nishishinjuku, Shinjuku-ku, Tokyo Inside the Tokyo Metropolitan Sewerage Bureau (72) Inventor Kenichiro Kono Shinjuku-ku, Tokyo 2-8-1 Nishi-Shinjuku Tokyo Metropolitan Sewerage Bureau F-term (reference) 2G059 AA01 BB04 CC19 EE02 FF06 GG01 GG08 JJ02 JJ11 JJ17 KK01 LL04 NN01 NN03

Claims (7)

[Claims] An apparatus for measuring the concentration of a turbid component in a liquid to be measured by detecting diffuse reflection light of laser light emitted toward the liquid to be measured, comprising: an optical fiber for emitting laser light; A concentration measuring device, wherein a plurality of optical fibers for light reception are bundled to constitute one sensor unit. 2. The concentration measuring apparatus according to claim 1, wherein a total of 100 or more optical fibers are bundled. 3. The concentration measuring apparatus according to claim 1, wherein a light emitting optical fiber and a light receiving optical fiber are randomly arranged on a sensor surface of the sensor section. 4. The concentration measuring device according to claim 1, wherein a light emitting optical fiber is arranged at a central portion of the sensor surface of the sensor section, and a light receiving optical fiber is arranged around the optical fiber. 5. The concentration measuring apparatus according to claim 1, wherein a light receiving optical fiber is disposed at a central portion of the sensor surface of the sensor section, and a light emitting optical fiber is disposed around the optical fiber. 6. The concentration measuring device according to claim 1, wherein a light-emitting optical fiber is arranged on one half of the sensor surface of the sensor section, and a light-receiving optical fiber is arranged on the other half. 7. The concentration measuring apparatus according to claim 1, wherein the laser light is supplied to the optical fiber for light emission by pulse driving.