JPWO2015111207A1 - Fluid concentration measuring device - Google Patents

Abstract

An object of the present invention is to make it possible to measure the concentration of a fluid flowing in a pipe line having a light-transmitting pipe wall with high accuracy by eliminating measurement errors caused by variations in sensitivity of light receiving elements and optical axis deviations. is there. In an apparatus for measuring the concentration of a fluid flowing in a pipe line having a light transmissive pipe wall, light is supplied into the pipe line from at least one light supply point on the surface of the pipe line. A light source and a plurality of light-receiving elements that are located on the opposite side of the diameter direction of the conduit with respect to the light supply location and that are arranged in a straight line at fine intervals at equal intervals in the extending direction of the conduit The light received by the element from the light supply point into the pipe and passed through the wall of the pipe and the fluid in the pipe is received by each of the light receiving elements. The concentration of the fluid based on the Lambert-Beer law from the intensity of the light received by each of the light receiving elements of the line sensor and the intervals between the light receiving elements. Output Those comprising a, a density output means. [Selection] Figure 6

Description

  The present invention relates to an apparatus for measuring the concentration of a fluid flowing in a light-transmitting pipe line based on the Lambert-Beer law.

  As a conventional fluid concentration measuring device, for example, the one described in Patent Document 1 is known, and the measuring method and measuring device here measure the concentration of a processing liquid as a fluid for cleaning a semiconductor wafer, A plurality of measuring bodies are provided in the middle of the processing liquid supply pipe, and a light transmitting part in which the optical path length of the light passing through the processing liquid is different is provided in each measuring body, and the optical path length corresponding to the properties of the processing liquid is provided. The light from the light source is supplied to the light transmission part, the light transmitted through the processing liquid in the light transmission part is received by the photodetector, the intensity of the light is examined, and the Lambert-Beer law is determined from the intensity of the light. Based on this, the concentration of the treatment liquid is obtained.

Japanese Patent Laid-Open No. 10-325797

  However, if the conventional device is applied to measure the concentration of a fluid such as blood or a chemical solution flowing in a light-transmitting conduit such as a resin tube or a glass tube, light is transmitted to the optical path crossing the light-transmitting conduit. Although it is necessary to pass through, it is difficult to actually measure the inner diameter of the pipe and the wall thickness of the pipe as the optical path length, and in particular, in the case of a resin tube that can deform the pipe, the inner diameter may change due to the deformation. Therefore, it is very difficult to measure the concentration of blood, chemicals, etc. in such a case, and it has been practically impossible to measure the concentration.

For this reason, as shown in FIG. 1, the inventor of the present application transmits light from three light emitting elements 1 each consisting of an LED (light emitting diode) or LD (laser diode) to a resin tube 2 as a light transmissive conduit. The light is received by three light receiving elements 3 including photodiodes, phototransistors, and the like that cross each other at three equal intervals (light receiving intervals L _N ) and oppose each other in the diameter direction of the three light emitting elements 1 and the resin tube 2. The light intensity at each location is obtained, and the light intensity and fluid concentration are determined from the distance of the geometrical light path LP between the three light emitting elements 1 and the light receiving elements 3 in combination. By eliminating the influence of the inner diameter and wall thickness of the resin tube 2 from the calculation based on the Lambert-Beer law, It proposes a fluid density measuring device for determining the concentration of the fluid flowing through the over Bed 2 above (PCT / JP2013 / 54664 International Patent Application).

  In this fluid concentration measuring device, when the resin tube 2 as a pipe line is limited and the inner diameter and wall thickness thereof are considered to be constant, the front side of the light supply point at the left end shown in FIG. The optical path LP when receiving light by the light receiving element and the immediately adjacent light receiving element, and the optical path when receiving light by the light receiving element immediately adjacent to the front of the left end light supply location shown in FIG. By setting LP, the concentration of the fluid flowing in the resin tube 2 can be determined within a certain range of error by the combination of one light emitting element 1 and two light receiving elements 3.

  However, in the previously proposed fluid concentration measuring apparatus, measurement errors occur when the light receiving sensitivities of the three light receiving elements 3 are different from each other, and it is difficult to adjust them, and the light emitting element 1 and the light receiving element 3 However, it was found that there is still room for improvement in order to further improve the calculation accuracy because a measurement error occurs even if the optical axis of the lens is shifted in the direction in which the pipe extends.

  On the other hand, line sensors have been known in recent years as electronic components having light receiving elements. In a line sensor, a large number of light receiving elements are arranged in a straight line at equal intervals and the sensitivity of these light receiving elements is high. They are adjusted to be the same.

In view of the above points, the present invention advantageously solves the problems of the conventional fluid concentration measuring device by using a line sensor, and the fluid concentration measuring device of the present invention has a light-transmitting tube wall. In a device for measuring the concentration of a fluid flowing in a pipeline,
A light source that supplies light into the conduit from at least one light supply location on the surface of the conduit;
The light supply point is formed by a plurality of light receiving elements that are located on the opposite side of the diameter direction of the pipe line with respect to the light supply point and are linearly arranged at equal intervals in the extending direction of the pipe line. The light that is supplied into the pipe from the inside and that has passed through the wall of the pipe and the fluid in the pipe is received, and signals indicating the intensity of the light received by each of the light receiving elements. A line sensor that outputs
Fluid concentration output means for obtaining and outputting the concentration of the fluid based on the Lambert-Beer law from the intensity of light received by each of the light receiving elements of the line sensor and the interval between the light receiving elements;
It is characterized by comprising.

  In the fluid concentration measuring apparatus of the present invention, when measuring the concentration of the fluid flowing in the pipe line having a light-transmitting tube wall such as a resin tube, the light source is at least on the surface of the pipe line. Light is supplied into the pipeline from one light supply location, and the line sensors are located on the opposite side of the diameter direction of the pipeline with respect to the light supply location and are equal to each other in the extending direction of the pipeline. A large number (for example, 32 or more) of light receiving elements having the same sensitivity (that is, adjusted to the same sensitivity to each other) arranged at intervals are supplied from the light supply point into the pipe line, and within the wall of the pipe line and The light that has passed through the fluid in the pipe line is received, and a signal indicating the intensity of the light received by each of the light receiving elements is output. The intensity of light received by each light receiving element And a number of Lambertian from the interval of the light receiving element thereof - obtains and outputs the density of the fluid based on Beer's Law.

  Therefore, according to the fluid concentration measuring apparatus of the present invention, the light receiving sensitivities of a large number of light receiving elements are substantially the same as each other in advance, and it is not necessary to make adjustments to align the sensitivities. Since the optical axis of the light emitting element substantially coincides with any one of the many light receiving elements, the measurement error due to variations in light receiving sensitivity or optical axis deviation is substantially reduced. However, it is possible to measure the concentration of fluid such as blood and chemicals flowing through a pipe line having a light transmissive tube wall such as a resin tube with high accuracy.

  In the fluid concentration measuring apparatus according to the present invention, the light source supplies light into the conduit from a plurality of light supply locations on the surface of the conduit, and the fluid concentration output means includes the plurality of fluid concentration output means. By correlating the relationship between the light intensity and the fluid concentration based on the geometric position of the light receiving element and the light receiving element whose optical axis coincides with the light supply location, the light flows in the pipeline based on the Lambert-Beer law. The concentration of the fluid may be obtained, and in this way, the influence of the inner diameter and wall thickness of the pipeline is removed from the calculation based on the Lambert-Beer law, and the concentration of the fluid flowing in the pipeline is obtained. it can.

  Further, in the fluid concentration measuring apparatus of the present invention, the fluid concentration output means uses the light receiving element having the highest received light intensity among the plurality of light receiving elements as a light receiving element whose optical axis coincides with the light supply location. The concentration of the fluid flowing in the pipe line may be obtained based on the Lambert-Beer law. In this way, the error due to the deviation of the optical axis is substantially eliminated from the calculation based on the Lambert-Beer law. The concentration of the fluid flowing in the pipe line can be obtained with high accuracy.

  Furthermore, in the fluid concentration measuring apparatus according to the present invention, the light source supplies light having different wavelengths from the plurality of light supply locations on the surface of the conduit into the conduit, and the fluid concentration output means includes: The Lambert-Beer law is obtained by correlating the relationship between the light intensity of each wavelength and the concentration of the fluid from the geometrical positional relationship between the plurality of light supply locations and the light receiving element whose optical axis coincides with the plurality of light supply locations. It is also possible to obtain the concentration of fluid flowing in the pipeline based on the above, and in this way, using the multiple types of light having different wavelengths, the multiple types flowing in the pipeline from the calculation based on the Lambert-Beer law The concentration of the fluid can be determined.

  In the fluid concentration measuring apparatus according to the present invention, the fluid concentration output means includes a distribution pattern of light intensity received by the multiple light receiving elements in a predetermined range of the line sensor or an area of a region surrounded by the distribution pattern. May be obtained and output by comparing the light intensity distribution pattern obtained and stored in advance or the area of the region surrounded by the distribution pattern, and if such a distribution pattern is used, The fluid concentration can be easily obtained and output in a short time from the intensity of the light received by a large number of light receiving elements.

It is explanatory drawing which shows typically the optical path setting of the fluid concentration measuring apparatus which the inventor proposed previously. (A) is explanatory drawing which shows the optical path in case the said fluid concentration measuring apparatus light-receives with the light receiving element of the front of the light supply location of a left end, and the light receiving element immediately adjacent to it, (b) is the left side of the said fluid concentration measuring apparatus. It is explanatory drawing which shows the optical path in the case of light-receiving with the light receiving element immediately adjacent to the front of the light supply location of this, and a further adjacent light receiving element. It is explanatory drawing which shows the principle of one Embodiment of the fluid concentration measuring apparatus of this invention. It is explanatory drawing which shows the example of a distribution pattern of the intensity | strength of the light which many light receiving elements of the line sensor each received from one light supply location in the fluid concentration measuring apparatus of the said embodiment. It is explanatory drawing which shows the distribution pattern example of the intensity | strength of the light which the many light receiving elements of the line sensor each received from two light supply locations in the fluid concentration measuring apparatus of the said embodiment. It is a block diagram which shows one Example of the fluid concentration measuring apparatus of the said embodiment. It is explanatory drawing which shows the relationship between the light wavelength and the light absorption characteristic of oxygenated hemoglobin of arterial blood and deoxygenated hemoglobin of venous blood.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 is an explanatory view showing the principle of one embodiment of the fluid concentration measuring apparatus of the present invention. In the present embodiment, as shown in the drawing, when light from the light emitting element 1 as a light source is supplied into the pipe from one light supply place on the outer surface of the pipe, for example, the light is transmitted in the wall of the pipe and It passes through the fluid in the pipeline and diffuses during the passage, and is located on the opposite side of the diameter direction of the pipeline with respect to the light supply location and at equal intervals in the extending direction of the pipeline. The line sensor 4 having a large number of light receiving elements 3 arranged in a straight line reaches the large number of light receiving elements 3, the large number of light receiving elements 3 receive the light that has reached the line sensor 4, and the line sensor 4 Each of the light receiving elements 3 outputs a signal indicating the intensity of light received. Then, the fluid concentration output means obtains the concentration of the fluid based on the Lambert-Beer law from the intensity of the light received by each of the light receiving elements 3 of the line sensor 4 and the distance between the many light receiving elements 3. Output.

Here, since the multiple light receiving elements 3 of the line sensor 4 are adjusted in advance to the same sensitivity, density measurement errors due to sensitivity variations among the light receiving elements 3 do not substantially occur. In addition, since the intervals between the many light receiving elements 3 of the line sensor 4 are constant and known in advance, by using any of the light receiving elements 3 among them, FIGS. The optical path from the light supply location to the light receiving element as shown in (2) can be set at an arbitrary light receiving interval (pitch) _LN . As shown in FIGS. 1 and 2, a plurality of light-emitting elements 1 and a plurality of light-receiving elements 3 are opposed to each other in the diameter direction with a resin tube 2 serving as a pipe interposed between the light-emitting elements 1 and the plurality of light-receiving elements 3. When setting the optical path LP to the light path, it is necessary to appropriately set the light receiving interval L _{N according} to the light emission intensity and the light receiving sensitivity. However, since the line sensor 4 has a large number of light receiving elements 3, the light receiving element 3 receives light. For example, when the maximum intensity level is large, the light receiving interval L _N is increased to reduce the measurement error, and when the maximum intensity level is small, the light receiving interval L _N is decreased to increase the measurement sensitivity. Etc. can be performed.

  The intensity of the light output from the many light receiving elements 3 of the line sensor 4 is shown in FIG. 4 when there is one light supply location due to the diffusion of light in the walls of the pipes and in the fluid in the pipes. In this manner, the distribution pattern P has one mountain shape, and when there are two light supply locations, the distribution patterns P1 and P2 have two mountain shapes as shown in FIG. The horizontal axis of these distribution patterns indicates the position of the light receiving element 3 on the line sensor 4, and the vertical axis indicates the intensity of light output from the light receiving element 3. Therefore, the optical axis of the light receiving element 3 having the maximum light intensity is positioned substantially coincident with the optical axis of the light emitting element 1 orthogonal to the extending direction of the duct. From the output signal of the light receiving element 3 whose optical axes substantially coincide with each other, it is possible to perform highly accurate concentration measurement using an optical path orthogonal to the extending direction of the pipe.

  Further, the shape of the distribution pattern P with respect to the intensity of received light in a predetermined range in the extending direction of the line sensor 4, for example, in a predetermined range centered on the position of the light receiving element 3 whose optical axis substantially coincides with the light emitting element 1. Alternatively, the area of the region S surrounded by the distribution pattern P in the predetermined range is compared with the shape or area of the distribution pattern P for each of a plurality of types of fluid concentrations acquired and recorded in advance. By complementing, the fluid concentration may be obtained.

  Further, as shown in FIG. 5, when the line sensor 4 is opposed to a plurality of light emitting elements 1 having different wavelengths of light emitted from each other, the position of the light receiving element 3 whose optical axis coincides with each light emitting element 1 is estimated. As a result, the light intensity distribution patterns P1 and P2 at the respective wavelengths can be obtained, so that information from the light absorption patterns at the respective wavelengths of the fluid to be measured can also be obtained.

  FIG. 6 is a configuration diagram showing a blood concentration measuring device that can be used to measure a blood volume (BV) during artificial dialysis or the like as an example of the fluid concentration measuring device of the above embodiment. This blood concentration measuring apparatus outputs two light emitting elements 1 each composed of, for example, a light emitting diode (LED), a large number of light receiving elements 3 each composed of, for example, a phototransistor, and signals of these light receiving elements 3 sequentially with time. A line sensor 4 having a large number of charge coupled devices (CCDs) (not shown) is arranged in a tube holder 5 that detachably holds a resin tube 2 serving as a conduit so as to face the resin tube 2 in the diameter direction. The two light emitting elements 1 and the many light receiving elements 3 of the line sensor 4 are each aligned in the extending direction of the resin tube 2.

  Here, the tube holder 5 is formed with a through hole 5a in the diameter direction at each position of the two light emitting elements 1, and the light emitted by the light emitting elements 1 is transmitted from the through hole 5a at a predetermined light supply location. The tube holder 5 can be supplied to the resin tube 2, and the tube holder 5 is formed with an elongated hole 5 b in the axial direction through which the line sensor 4 penetrates at a position facing the two light emitting elements 1 in the diameter direction. By exposing the line sensor 4 in the tube holder 5 from the long hole 5b, the light passing through the resin tube 2 in the tube holder 5 can be supplied to the line sensor 4.

Here, one of the two light emitting elements 1 emits light having a wavelength of 660 nm, and the other emits light having a wavelength of 805 nm. FIG. 7 shows the wavelength of light and oxygenated hemoglobin HbO _{2 of} arterial blood and As shown in the relationship with the absorption characteristics of venous blood deoxygenated hemoglobin Hb, light having a wavelength of 660 nm has the most different light absorption characteristics of oxygenated hemoglobin HbO ₂ and deoxygenated hemoglobin Hb, and light having a wavelength of 805 nm The light absorption characteristics of oxygenated hemoglobin HbO ₂ and deoxygenated hemoglobin Hb are almost the same.

Therefore, by using the light emitting element 1 that emits light having a wavelength of 805 nm, the concentrations of both oxygenated hemoglobin HbO ₂ and deoxygenated hemoglobin Hb can be measured together, and light having a wavelength of 660 nm is emitted. By using the light emitting element 1, the concentration of oxygenated hemoglobin HbO ₂ can be selectively measured, and the concentration of deoxygenated hemoglobin Hb can also be measured from the measurement results.

  Further, the line sensor 4 has, for example, 128 light receiving elements 3 at 8 μ pitch, and these light receiving elements 3 are adjusted in advance so that the light receiving sensitivities are equal to each other, and the level according to the intensity of the received light. The CCD outputs these electrical signals, and the CCD arranges these electrical signals over time and outputs them as analog output signals.

  In this embodiment, the two LED drivers 6 cause the two light emitting elements 1 to emit light, and the line sensor driver 7 reads the analog output signals of the many light receiving elements 3 arranged over time from the line sensor 4. The analog data is output to the analog-digital converter (A / D) 8, and the A / D 8 converts the analog data into digital data and outputs the digital data to the central processing unit (CPU) 9.

  Based on a program stored in advance in a memory (not shown), the CPU 9 uses, for example, two light receiving elements whose optical axes coincide with the two light emitting elements 1 among the many light receiving elements 3 of the line sensor 4 from the digital data output from the A / D 8. The light intensity received by each of the plurality of light receiving elements 3 at a predetermined position including 3 is determined. For example, from the intensity of the received light and the length of the optical path LP from the light emitting element 1 to the light receiving element 3, Lambert Based on Beer's law, for example, a plurality of relational expressions are obtained with the wall thickness, inner diameter, etc. of the resin tube 2 as unknowns, and by combining them, the concentration of blood BD flowing in the resin tube 2 as shown by the arrows in the figure Is output. The specific calculation method based on the Lambert-Beer law is described in detail, for example, in the specifications of the PCT / JP2013 / 54664 international application and the PCT / JP2013 / 61486 international application previously filed by the present applicant. Have been described. Therefore, the CPU 9 functions as fluid concentration output means.

  The CPU 9 also sends a control signal to the two LED drivers 6 to cause the two light emitting elements 1 to emit light sequentially. For example, when the output signal level of the light receiving element 3 is lower than a predetermined value, the light emitted from the light emitting element 1 The light emitting element 1 is adjusted so that the intensity level of the light emitted from the light emitting element 1 is lowered when the output signal level of the light receiving element 3 is higher than a predetermined value. Output signal level suitable for concentration measurement.

  Therefore, according to the blood concentration measuring apparatus of this embodiment, the light receiving sensitivities of the large number of light receiving elements 3 are made substantially the same with each other in advance, and there is no need to adjust their sensitivity, and the light receiving elements 3 Are arranged in the extending direction of the resin tube 2, so that the optical axis of one of the many light receiving elements 3 and the light emitting element 1 substantially coincide with each other. Therefore, the concentration of blood flowing in the resin tube 2 can be measured with high accuracy.

  Further, according to the blood concentration measuring apparatus of this embodiment, the two light emitting elements 1 emit light into the resin tube 2 from the two light supply locations on the surface of the resin tube 2 corresponding to the position of the through hole 5a. And the CPU 9 correlates the relationship between the light intensity and the blood concentration from the two light supply locations and the geometrical positional relationship of the light receiving element 3 whose optical axis coincides with them. -Since the concentration of blood flowing in the resin tube 2 is obtained based on the Beer's law, the influence of the inner diameter and wall thickness of the resin tube 2 is removed from the calculation based on the Lambert-Beer's law, and the fluid flowing in the resin tube 2 is The concentration can be determined.

  In addition, according to the blood concentration measuring apparatus of this embodiment, the CPU 9 receives the light receiving element 3 having the highest intensity of received light among the many light receiving elements 3 of the line sensor 4 and whose optical axis coincides with the light supply location. Since the concentration of blood flowing in the resin tube 2 is obtained based on the Lambert-Beer law, the error due to the deviation of the optical axis is substantially eliminated from the calculation based on the Lambert-Beer law. The concentration of blood flowing through can be obtained with high accuracy.

  Furthermore, according to the blood concentration measuring apparatus of this embodiment, the two light emitting elements 1 supply light having different wavelengths from the two light supply locations on the surface of the resin tube 2 into the resin tube 2, and the CPU 9 The Lambert-Beer law is established by correlating the relationship between the light intensity of each wavelength and the blood concentration from the light supply locations and the geometric positional relationship of the light receiving elements 3 whose optical axes coincide with each other. Since the concentration of blood flowing in the resin tube 2 is calculated based on the above, the concentration of two types of blood components flowing in the resin tube 2 is calculated from the calculation based on the Lambert-Beer law using two types of light having different wavelengths. Can do.

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples, and can be appropriately changed within the scope of the claims. For example, in the apparatus of the above-described embodiment, the line sensor 4, the number of the light receiving elements 3 is 128 (128 pixels) and the interval pitch (pixel pitch) of the light receiving elements 3 is 8 μm. However, the line sensor 4 is not limited to this, and the number of the light receiving elements 3 is, for example, 64 As described above, if they are aligned with a length of several mm to several cm at a pitch of 4 μm or more, for example, they can be suitably used for the fluid concentration measuring device of the present invention. Further, a plurality of line sensors 4 may be arranged in parallel in the extending direction of the pipeline, or may be substituted by a two-dimensional photosensor having a large number of pixels aligned at least in the extending direction of the pipeline. In this case, it is possible to cope with the deviation of the optical axis in the circumferential direction or tangential direction of the pipe.

  In the apparatus of the above embodiment, light having a wavelength of about 805 nm is used as light having substantially the same extinction coefficient for both oxygenated hemoglobin of arterial blood and deoxygenated hemoglobin of venous blood. For example, light having a wavelength near 590 nm or 880 nm may be used.

  Furthermore, in the apparatus of the above embodiment, the concentration of blood as a liquid is measured. However, instead of this, it can also be used for measuring the concentration of other liquids, in which case the liquid is used as light supplied from the light source. It is preferable to select light having a wavelength with a high absorptance due to the difference in light intensity at the light receiving location depending on the thickness of the tube wall.

  Furthermore, in the apparatus of the above embodiment, the CPU 9 performs a calculation process based on the intensity of light output from the light receiving element 3 to obtain a blood concentration and outputs it, but instead of this, the line sensor 4 A plurality of types of distribution patterns P of the intensity of light output from the light receiving element 3 in a predetermined range or areas of the region S surrounded by the distribution pattern P in the predetermined range are acquired in advance and stored in the memory or the like. Compared with the shape or area of the distribution pattern P for each of the fluid concentrations, and if they do not match, the fluid concentration may be obtained by interpolating between the data. In this way, a large number of light receiving elements 3 can easily obtain and output the concentration of the fluid in a short time from the intensity of the received light.

  And in the apparatus of the said Example, although the light is supplied in two light supply locations and the light is received by the line sensor 4 and the intensity | strength of light is calculated | required, it replaces with this and one light supply location The light may be supplied by the line sensor 4 and the light intensity may be obtained by the line sensor 4 and the fluid concentration may be obtained from the light intensity. Alternatively, the light may be supplied at three or more light supply locations. Then, the light may be received by the line sensor 4 to obtain the light intensity, and the fluid concentration may be obtained with higher accuracy from the light intensity.

  Thus, according to the fluid concentration measuring apparatus method of the present invention, the light receiving sensitivities of a large number of light receiving elements are substantially the same as each other in advance, and it is not necessary to adjust the sensitivity to be uniform. Since the optical axis of the light emitting element substantially coincides with any one of the many light receiving elements, the measurement error due to variations in light receiving sensitivity or optical axis deviation is substantially reduced. However, it is possible to measure the concentration of fluid such as blood and chemicals flowing through a pipe line having a light transmissive tube wall such as a resin tube with high accuracy.

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Resin tube 3 Light receiving element 4 Line sensor 5 Tube holder 5a Through-hole 5b Long hole 6 LED driver 7 Line sensor driver 8 Analog-digital converter (A / D)
9 Central processing unit (CPU)
BD Blood L _N Light receiving interval LP Optical path P, P1, P2 Distribution pattern S region

Claims (5)

In an apparatus for measuring the concentration of a fluid flowing in a pipe line having a light transmissive pipe wall,
A light source that supplies light into the conduit from at least one light supply location on the surface of the conduit;
By a large number of light receiving elements that are located on the opposite side of the diameter direction of the pipe line with respect to the light supply location and are arranged in a straight line at a minute interval at equal intervals in the extending direction of the pipe line, The light supplied from the light supply point into the pipeline and received through the wall of the pipeline and the fluid in the pipeline is received, and the light received by each of the multiple light receiving elements is received. A line sensor that outputs a signal indicating intensity;
Fluid concentration output means for obtaining and outputting the concentration of the fluid based on the Lambert-Beer law from the intensity of light received by each of the light receiving elements of the line sensor and the interval between the light receiving elements;
A fluid concentration measuring device comprising: The light source supplies light into the conduit from a plurality of light supply locations on the surface of the conduit,
The fluid concentration output means correlates the relationship between the light intensity and the fluid concentration from the plurality of light supply locations and the geometric positional relationship between the light receiving elements whose optical axes coincide with each other. 2. The fluid concentration measuring apparatus according to claim 1, wherein the concentration of the fluid flowing in the pipe is obtained and output based on Beer's law.   The fluid concentration output means uses the light receiving element having the highest received light intensity among the plurality of light receiving elements as a light receiving element whose optical axis coincides with the light supply location, and flows in a pipeline based on the Lambert-Beer law. 3. The fluid concentration measuring device according to claim 1, wherein the concentration of the fluid is obtained and output. The light source supplies light having different wavelengths from the plurality of light supply locations on the surface of the pipeline into the pipeline,
The fluid concentration output means correlates the relationship between the light intensity of each wavelength and the concentration of the fluid from the plurality of light supply locations and the geometric positional relationship of the light receiving elements having the same optical axis. The fluid concentration measuring device according to any one of claims 1 to 3, wherein the concentration of the fluid flowing in the pipe line is obtained and output based on the Lambert-Beer law.   The fluid concentration output means obtains a light intensity distribution pattern received by the plurality of light receiving elements in a predetermined range of the line sensor or an area of a region surrounded by the distribution pattern in advance and stores the light intensity 5. The fluid concentration measuring apparatus according to claim 1, wherein the concentration of the fluid is obtained and output by comparing with the distribution pattern or the area of the region surrounded by the distribution pattern. 6.

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