JP2002365216A - Concentration measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concnetration measuring apparatus by which the concentration of a turbid component in a solution to be measured can be measured with high accuracy and with high sensitivity, even when the color of the turbid component in the solution to be measured is changed while the advantage of a concentration measurement by the reflection system of a laser beam is being utilized. SOLUTION: In the apparatus, the concnetration of the turbid component in the solution to be measured is measured by detecting the reflected light of the laser beam emitted toward the solution to be measured. In the concentration measuring apparatus, a plurality of light-emitting optical fibers and a plurality of light-receiving optical fibers are bundled respectively, concentration- sensor faces are constituted on their tips, a plurality of separate receiving- receiving optical fibers are arranged near the concentration-sensor faces, scattered-light-sensor faces which receive scattered light from the solution to be measured are constituted, and a signal processing means by which light- receiving signals by the concentration-sensor faces are compensated by using light-receiving signals by the scattered-light-sensor faces is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the concentration and turbidity 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. The present invention relates to a device for measuring the degree, and more particularly to a concentration measuring device capable of accurately measuring 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, the concentration of the turbid component is particularly high at 1% or more.
In particular, when the concentration is 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 light is blocked or absorbed by the turbid component, and when the turbid component is high in concentration, the attenuation of light on the transmitted light detection side becomes severe, so that high-sensitivity measurement becomes difficult. It is.

[0004] In order to solve such a problem in the transmitted light method in the case of high concentration measurement, it is considered that a method of detecting reflected light of 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. By detecting the reflected light in this way, regardless of the concentration of the turbid component, the reflected light to be detected is prevented from being greatly attenuated. Highly sensitive measurement is possible.

[0005]

However, as a result of tests and investigations by the present inventors, even in the above-described concentration measurement by the reflected light method, the color of the turbid component in the liquid to be measured, especially its brightness Changes, the concentration detection value varies,
It has been found that stable and accurate measurement may be difficult. For example, even when the concentrations confirmed by the dry weight method are the same, if the color of the turbid component in the liquid to be measured, particularly the brightness, is different, the actual concentration detection value may vary greatly.

Therefore, an object of the present invention is to focus on the advantage of the density measurement by the laser light reflection method as described above,
An object of the present invention is to provide a concentration measuring device capable of accurately measuring the concentration even when the color of a turbid component in a liquid to be measured fluctuates.

[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. In a device that measures by detecting reflected light of
A plurality of optical fibers for laser light emission and a plurality of optical fibers for light reception are bundled, a concentration sensor surface is formed at the tip thereof, and another plurality of optical fibers for light reception are arranged near the concentration sensor surface to be measured. Construct a scattered light sensor surface that receives scattered light from the liquid, and
Signal processing means for compensating for a light reception signal from the density sensor surface using a light reception signal from the scattered light sensor surface is provided.

[0008] In this concentration measuring device, it is preferable that the light emitting optical fiber and the light receiving optical fiber are randomly arranged when forming the above-mentioned concentration sensor surface. 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 on the density sensor surface, a light-emitting optical fiber is arranged at the center, and a light-receiving optical fiber is arranged around the light-receiving optical fiber. It is also possible to adopt a configuration in which a light emitting optical fiber is disposed, a configuration in which a light emitting optical fiber is disposed on one half surface, and a light receiving optical fiber on the other half surface, and the like.

The scattered light sensor surface may be formed in the vicinity of the concentration sensor surface so that a light receiving optical fiber is arranged separately from the concentration sensor surface so that scattered light from the liquid to be measured can be received. Preferably, it is preferably formed in an annular shape around the surface of the density sensor, so that scattered reflected light scattered around the surface of the concentration sensor can be efficiently received. In particular, in order to efficiently receive substantially only scattered light, an interval is provided between the scattered light sensor surface and the density sensor surface, and the reflected light to be received on the density sensor surface is more reliably detected by the density sensor surface. It is preferable that the scattered light to be received by the scattered light sensor surface is received by the scattered light sensor surface more reliably.

It is preferable that the signal processing means compensates the light reception signal from the density sensor surface substantially in real time using the light reception signal from the scattered light sensor surface. By real-time compensation, there is no time lag between the light reception signal by the density sensor surface to be compensated and the light reception signal by the scattered light sensor surface to perform compensation, and highly accurate compensation is possible. In particular, when noise occurs due to bubbles or the like in the liquid to be measured, the noise normally affects the light reception signal from the concentration sensor surface and the light reception signal from the scattered light sensor surface. It is possible to efficiently cancel and eliminate noise.

In the concentration measuring apparatus according to the present invention configured as described above, if the reflected light from the liquid to be measured is simply received and the concentration is measured based on the signal value, the liquid to be measured is
Paying attention to the problem that the measured value may fluctuate greatly when the color of the turbid component, especially the brightness, changes, and eliminates the effect of the change in brightness on the measured density value. The compensation is performed so that the actual concentration of the turbid component can be measured with higher accuracy. In other words, it is considered that the light that is relatively proportional to the actual concentration is the reflected light from the liquid to be measured, or the diffusely reflected light as described above. Since the factor of the scattered light is considered to be largely governed by the scattered light, the actual concentration can be reduced by efficiently picking up the scattered light component and compensating for the variance factor based on it. It is based on the basic technical idea of measuring with higher accuracy while suppressing it. Then, the scattered light can be efficiently received as only the scattered light component as much as possible by the scattered light sensor surface formed separately from the concentration sensor surface, and the accuracy and effectiveness of compensation are increased. With this compensation,
Varying components to the density measurement due to the color, especially the brightness, are removed, and the density measurement with no variation and high accuracy can be performed.

Further, even when other noise components for the concentration measurement, such as bubbles in the liquid to be measured, are generated, the noise components are substantially converted into a light reception signal from the concentration sensor surface and a light reception signal from the scattered light sensor surface. By performing the compensation in real time using the fact that the noise components are equally affected, it is possible to eliminate such noise components, and the density measurement can be performed with higher accuracy.

[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. 1 and 2 show a basic configuration of a concentration measuring apparatus according to an embodiment of the present invention, FIGS. 3 and 4 show examples of a circuit configuration for signal transmission / reception and signal processing, and FIG. An example of the state of compensation is shown.

In FIG. 1, reference numeral 1 denotes the entire concentration measuring device, and the concentration measuring device 1 is, for example, configured in the form of a sensor as a whole, 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 so-called diffuse reflection light type concentration measuring device for measuring the concentration of the turbid component 4 in 3.

In this 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. The laser light is emitted in a predetermined pulse form by pulse driving by the laser diode driving circuit 8 having an oscillator. The laser light emitted from the laser light emitting diode 7 is incident on the incident ends of a large number of light emitting optical fibers 11 bundled and held by an optical fiber fixing bracket 10 via a laser light diffusion plate 9.
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
The optical fiber 2 is formed on the density sensor surface 15 in a state where the relative position is fixed, for example, in the fixture 14, and the positions of the tip surfaces of the optical fibers are aligned. From the concentration sensor surface 15, the light is guided through the light emitting optical fiber 11, and the laser light emitted from the emission end of the light emitting optical fiber 11 is irradiated toward the liquid 3 to be measured.
The laser light 6 that has been diffused and reflected upon the turbid component 4 therein 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 density sensor surface 15 are performed through a glass plate 16 provided on the density sensor surface 15. The material of the glass plate 16 is not particularly limited, but sapphire glass which is hard and hard to be scratched, is chemically stable, has excellent acid resistance, alkali resistance, and solvent resistance and is thermally stable is preferable. Further, 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. 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 the lens, a plano-convex lens or the like having a lens function by forming the density sensor surface side as a flat surface and the other surface side (the liquid contact side surface) as a convex surface is preferable.

The reflected light 6 of the laser beam received from the incident end of the light receiving optical fiber 12 is
2 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 reflected light emitted from the 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 the present embodiment, the received light amount signal of the photodiode 19 is amplified by the concentration measurement amplifier circuit 20 to be output as a signal having a magnitude suitable for concentration measurement, and the output signal is output to an operation compensation circuit as signal processing means. 21.

On the density sensor surface 15, for example, as shown in FIG. 2, a plurality of bundled light emitting optical fibers 11 and light receiving optical fibers 12 are arranged at random, and one density sensor surface 15 is formed. Have been. In the vicinity of the density sensor surface 15, in the present embodiment, around the density sensor surface 15, an annular space 22 is provided separately from the density sensor surface 15 and with an appropriate distance 22 from the density sensor surface 15. A scattered light sensor surface 23 is configured. The scattered light sensor surface 23 is formed by arranging a plurality of light receiving optical fibers 24 different from the light receiving optical fiber 12 around the concentration sensor surface 15 in a ring shape. The scattered light 25 is received. This change in the scattered light 25 is generally
Appears corresponding to the change in the color and brightness of the liquid 3 to be measured, particularly the turbid component 4 therein. The light receiving optical fiber 24 for the scattered light 25 may be fixed by using the above-described fixing fitting 14, or may be fixed by providing another annular fitting 26.

The scattered light 25 of the laser light received from the incident end of the light receiving optical fiber 24 for the scattered light 25 is guided in the light receiving optical fiber 24 and is emitted from the emission end which is the opposite end. You. Also at the end of the light receiving optical fiber 24 on the emission end side, a large number of light receiving optical fibers 2
4 are held in a state of being bundled by the optical fiber fixture 27.

In this embodiment, the scattered light emitted from the emission end of the light receiving optical fiber 24 passes through the visible light cut filter 28 and passes through a photodiode as a scattered light receiving element in the same manner as in the light receiving optical fiber 12 described above. The light is received by 29 and its light amount is detected. By disposing the visible light cut filter 28, the influence of disturbance light (for example, disturbance light from a fluorescent lamp or the like) on the detection of scattered light can be reduced. In the present embodiment, the received light amount signal of the photodiode 29 is amplified by the compensation signal measurement amplifier circuit 30 to be output as a compensation signal having an appropriate magnitude, and the output signal is used as the signal processing means described above. The signal is sent to the operation compensation circuit 21.

The emission and reception of laser light and their signal processing circuits are configured, for example, as shown in FIG.
In FIG. 3, drive and control power is supplied from a DC stabilized power supply 31, and irradiation light 5 is emitted from a laser light emitting diode 7 with a drive pulse from a laser diode drive circuit 8. At this time, the synchronization pulse 32 synchronizes the laser diode drive pulse with the control pulse and the arithmetic processing. The light receiving signal of the reflected light 6 is the photodiode 1
9 and the signal of the amount of received light is
In addition, the received light signal of the scattered light 25 is detected by the photodiode 29, and the received light amount signal is amplified by the compensation signal measurement amplifier circuit 30. These amplifier circuits 20,
In 30, the zero point adjustment of the signal and the span adjustment in the measurement of a signal of a certain magnitude or a full-scale signal can be performed (zero and span adjustment means 33 and 34). The signal from the concentration measurement amplification circuit 20 and the signal from the compensation signal measurement amplification circuit 30 are input to the operation compensation circuit 21, where the compensation based on the scattered light detection signal is performed. In the operation compensation, a signal obtained by adjusting the above-mentioned zero point and span (33, 34) is used, and the span can be adjusted even after the operation compensation (span adjusting means 35). The compensated signal is output as a final density measurement value 36 that has been compensated based on scattered light.

The operation compensation circuit 21 has a basic configuration as shown in FIG. 4, for example, multiplies the signal from the concentration measurement amplification circuit 20 by a correction coefficient, and then calculates the compensation signal value from the compensation signal measurement amplification circuit 30. By subtraction, it is output as the final density measurement value 36. The correction coefficient is Ri
/ FX (Ri: resistance 37, FX: sensitivity adjuster 38), and the final density output value = (measured density value × correction coefficient) −compensation signal value is output by the comparator or amplifier 39.

That is, in the above-described operation compensation circuit 21,
Compensation is performed as shown in FIG. Concentration sensor surface 1
Measurement signal pulse 40 of the reflected light reception amount signal received at 5
As shown in FIG. 5, includes a variation 41 influenced by the color and brightness of the turbid component, and further includes a noise component 42 due to bubbles or the like in some cases. On the other hand, the scattered light reception amount signal received by the scattered light sensor surface 23 is obtained by extracting the fluctuation 41 which is affected by the color or brightness of the turbid component, and the noise component 42 due to bubbles or the like is detected by the density sensor surface. Since the light reception signal at 15 and the light reception signal at the scattered light sensor surface 23 appear substantially equally, a compensation signal pulse 43 as shown in FIG. 5 is obtained. In the operation compensation circuit 21, the measurement signal pulse 40 is compensated for by the compensation signal pulse 43 (the compensation signal pulse 43 is subtracted from the measurement signal pulse 40). This signal pulse 44 is output as the above-mentioned final output signal 36, that is, as a measured concentration value of the liquid 3 to be measured.

By performing such compensation, even if the color of the turbid component in the liquid 3 to be measured, especially the brightness, fluctuates, the variable component can be eliminated, and the concentration component of the liquid 3 to be measured can be eliminated. It is possible to measure with high accuracy and high sensitivity as only a signal. In particular, as shown in FIG. 5, by synchronizing each pulse and compensating substantially in real time, it becomes possible to significantly increase the measurement accuracy. Also, even if noise components 42 due to bubbles or the like are generated, compensation is performed by utilizing the fact that the noise components 42 appear equally in synchronization with the compensation signal pulse, so that these noise components can be eliminated very efficiently. You. Therefore, the density of the measurement target liquid 3 to be measured is measured with extremely high accuracy and high sensitivity without being affected by color fluctuations and with noise components removed.

In order to confirm the effect of the above-described compensation, first, the following basic confirmation test was performed. A white poster color is added to the sludge supplied to the dehydrator in the actual plant A to forcibly change the color (brightness) of the sludge,
The measured value of the sludge concentration was measured with and without the above-described compensation. When the sludge concentration of the raw sludge supplied to the dehydrator was confirmed by a dry weight method, it was 3.0.
% (Raw sludge: sample No. 1). One liter of this raw sludge was prepared by adding 0.5 g of white poster color (sample No. 2) and one obtained by adding 1.0 g (sample No. 3). These sample Nos.
2, No. In No. 3, since the amount of the white poster color added to the sludge was 1/1000 or less, it had substantially the same concentration (3.0%) as the raw sludge (Sample No. 1). These sample Nos. 1 to No. When the lightness of the sample No. 3 was measured using Munsell standard colored paper, the sample No. 3 was calculated as an average value of three observers. 1 is Munsell N2,
Sample No. 2 is Munsell N3.5, sample No.
3 was Munsell N 5.33.

Using a density measuring device having the structure shown in FIGS. 1 and 3, first, fresh water (tap water) is put into a black bottle of about 500 cc with low reflection to measure the density, and the final output is obtained. The signal processing system and the output system were adjusted such that the compensated density measurement value became 0.00% (zero point adjustment).
Next, the sample No. For 1 (raw sludge), the signal processing system and output system were adjusted (span adjustment) so that the compensated concentration measurement value was 3.00% (confirmed value by dry weight method). In this adjustment state, the sample No. whose lightness was forcibly changed was used. 2 and sample no. Regarding No. 3, the density measurement values were measured when no compensation was performed and when the compensation was performed. When the compensation was not performed, the change in brightness was too large and the scale was over, resulting in measurement failure. In this case, a sufficiently measurable signal was obtained. Table 1 shows the results.

[0028]

[Table 1]

As shown in Table 1, it was confirmed that by performing the compensation according to the present invention, it is possible to perform the density measurement with the compensation for the variation due to the color, which can be sufficiently used practically. However, at the basic confirmation test stage shown in Table 1, the sample No. 2 and sample no. It is desirable that the density measured value after the compensation of 3 is 3.00% (in that case, the variation due to the color has been completely compensated), but the circuit is actually adjusted to that extent I couldn't do it. However, in practice, this adjustment can be made almost completely, or until a measurement value with considerably high accuracy can be obtained by repeating the adjustment by trial and error.

Therefore, a number of experiments were performed on sludge from an actual plant for such more appropriate adjustment, and a test was conducted to more specifically confirm the effect of the compensation of the present invention. 6 to 11 show the results. FIG. 6 shows a state in which the sludge supplied to the dehydrator in the actual plant A is adjusted with the concentration measuring device (sensor) having the configuration shown in FIGS. This shows the results of taking samples and measuring them. It is mainly possible to read the sludge concentration (%) confirmed by the dry weight method and the voltage output of the measuring device for a large number of samples with varying colors and lightness. It is confirmed how much linearity can be maintained between the measured value (voltage: V) by the concentration measuring device having the compensating function according to the present invention. FIG. 7 shows the result of measuring the same number of samples without compensation. As shown in FIG. 7, when measured without compensation, the color and brightness fluctuated, and without compensation, the sludge concentration (%) confirmed by the dry weight method was measured by a concentration measurement device. Cannot maintain a clear linearity, and it is therefore difficult to use a reflection-type concentration measuring apparatus for measuring a sludge concentration of a relatively high concentration (1% or more) in which the color and brightness vary greatly. However, as shown in FIG. 6, the present invention compensates for variations in color and lightness based on the received light signal of scattered light, so that a clear linearity can be secured. It was found that a concentration measurement corresponding almost completely to the concentration (%) of 1: 1 was obtained. That is, the correctness of the basic technical concept of the present invention, in which the variation in color or brightness is compensated based on the received signal of scattered light, thereby greatly increasing the measurement accuracy and sensitivity of the reflection type density measuring device, is proved. Was.

FIGS. 8 and 9 show the results of a similar test conducted on a large number of samples of the gravity-enriched sludge in Plant A. FIG. 8 shows the case where compensation according to the present invention was performed, and FIG. Are shown, respectively, in the case of not performing. FIGS. 8 and 9 can be said to be exactly the same as those in FIGS. 6 and 7, and the effect of the present invention could be confirmed. Further, FIGS. 10 and 11 show the results of similarly tested digested and washed sludge on a large number of samples in another plant B. FIG. 10 shows a case where compensation according to the present invention was performed, and FIG. The results when no compensation is performed are shown. 10 and 11
Thus, the same can be said for FIGS. 6, 7, 8 and 9, and the effect of the present invention could be confirmed.

[0032]

As described above, according to the concentration measuring apparatus of the present invention, when the color of the turbid component in the liquid to be measured fluctuates while taking advantage of the concentration measurement by the laser beam reflection method. Also, by performing compensation based on the received light signal of the scattered light, the concentration can be measured with high accuracy and high sensitivity. In particular, if compensation is performed in real time, in addition to compensation for color and lightness, it is possible to eliminate noise components due to bubbles and the like, and it becomes possible to perform measurement with higher accuracy and higher sensitivity.

[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 partial schematic configuration diagram of the apparatus of FIG.

FIG. 3 is a block diagram showing a circuit configuration of the device of FIG. 1;

FIG. 4 is a schematic circuit diagram showing a basic concept of compensation in the circuit of FIG.

FIG. 5 is an explanatory diagram of each pulse showing a basic concept of compensation according to the present invention.

FIG. 6 shows a concentration measuring apparatus according to the present invention in a real plant A.
FIG. 6 is a graph showing the relationship between sludge concentration and output voltage, showing the results of tests on sludge in FIG.

FIG. 7 is a diagram showing the relationship between the sludge concentration and the output voltage, showing the result of the same test as shown in FIG. 6 performed without performing the compensation according to the present invention.

FIG. 8 shows a concentration measuring apparatus according to the present invention in a real plant A.
FIG. 4 is a graph showing the relationship between the sludge concentration and the output voltage, showing the results of tests on different types of sludge in FIG.

9 is a graph showing the relationship between the sludge concentration and the output voltage, showing the result of the same test as shown in FIG. 8 performed without performing the compensation according to the present invention.

FIG. 10 is a graph showing the relationship between sludge concentration and output voltage, showing the results of testing the concentration measuring device according to the present invention on sludge in an actual plant B.

FIG. 11 is a graph showing the relationship between the sludge concentration and the output voltage, showing the results when the same test as shown in FIG. 10 is performed without performing the compensation according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concentration measuring apparatus 2 Pipe 3 Liquid to be measured 4 Turbid component 5 Emitted laser light 6 Diffuse reflected light of laser light 7 Laser light emitting diode 8 Laser diode drive circuit 9 Laser light diffusion plate 10 Optical fiber fixing bracket 11 Optical fiber for light emission 12 , 24 Light receiving optical fiber 13 Sensor part 14 Fixing bracket 15 Density sensor surface 16 Glass plate 17, 27 Optical fiber fixing bracket 18, 28 Visible light cut filter 19, 29 Photodiode 20 Concentration measuring amplifier circuit 21 Operation compensation circuit 22 Interval 23 Scattered light Sensor surface 25 Scattered light 26 Annular metal fitting 30 Compensation signal measurement amplifier circuit 31 DC stabilized power supply 32 Synchronization pulse 33, 34 Zero, span adjustment means 35 Span adjustment means 36 Concentration measurement value (output signal) 37 Resistance 38 Sensitivity adjuster 39 Comparison Instrument or amplifier 40 Measurement signal pulse 41 Fluctuation affected by color and brightness 42 Noise component due to bubbles 43 Compensation signal pulse 44 Signal pulse consisting only of turbid component concentration

 ──────────────────────────────────────────────────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 591043581 2-81 Nishishinjuku, Shinjuku-ku, Tokyo (72) Inventor Toshiro Harada 2-6-2 Otemachi, Chiyoda-ku, Tokyo Tokyo Metropolitan Sewer Service Co., Ltd. (72) Inventor Tomoyuki Hayashi 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Seihei Yano 3-9-2 Nihonbashi, Chuo-ku, Tokyo Tomoe Engineering Co., Ltd. (72) Inventor Shigeo Sato 2-chome Osaki, Shinagawa-ku, Tokyo No. 1-17 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 5-chome Sendagaya, Shibuya-ku, Tokyo 32-7 Shibaura System Co., Ltd. (72) Inventor Tatsuya Sakamoto 2-8-1, Nishishinjuku, Shinjuku-ku, Tokyo Inside the Tokyo Metropolitan Sewerage Bureau (72) Inventor Yoshitaka Sugiyama 2-8, Nishishinjuku, Shinjuku-ku, Tokyo No. 1 Tokyo Metropolitan Sewerage Bureau F-term (reference) 2G059 AA01 BB06 CC20 EE02 GG01 JJ02 JJ17 KK03 MM01 MM15 MM16 NN01

Claims (5)

[Claims] An apparatus for measuring the concentration of a turbid component in a liquid to be measured by detecting reflected light of laser light emitted toward the liquid to be measured. A plurality of optical fibers are bundled, and a concentration sensor surface is formed at the tip thereof, and another plurality of light receiving optical fibers are arranged near the concentration sensor surface to receive scattered light from the liquid to be measured. A concentration measuring device comprising a scattered light sensor surface, and signal processing means for compensating a light reception signal from the concentration sensor surface using the light reception signal from the scattered light sensor surface. 2. The concentration measuring device according to claim 1, wherein a light emitting optical fiber and a light receiving optical fiber are randomly arranged on the surface of the concentration sensor. 3. The concentration measuring device according to claim 1, wherein the scattered light sensor surface is formed around the concentration sensor surface. 4. The concentration measuring device according to claim 1, wherein a space is provided between the scattered light sensor surface and the concentration sensor surface. 5. The concentration measuring apparatus according to claim 1, wherein the signal processing means compensates a light reception signal from the density sensor surface substantially in real time by using a light reception signal from the scattered light sensor surface.