JP2013120064A - Turbidity chromaticity meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbidity chromaticity meter capable of reducing necessity of maintenance work and eliminating necessity of a spectrometer, allowed to be directly attached to a pipeline or a storage tank in which liquid exists, and capable of cost reduction and real time property of measurement.SOLUTION: The turbidity chromaticity meter includes: an LED 1a for irradiating light of a first wavelength to liquid to be measured; an LED 1b for irradiating light of a second wavelength to the liquid; an optical sensor 3a for receiving light of the first wavelength irradiated from the LED 1a and transmitted through the liquid and converting the light into an electric signal; an optical sensor 3b for receiving light of the second wavelength irradiated from the LED 1b and transmitted through the liquid and converting the light into an electric signal; and a processor 30 for calculating turbidity of the liquid based on the electric signal from the LED 1a and calculating chromaticity of the liquid based on the electric signal from the LED 1b.

Description

  The present invention calculates the turbidity and chromaticity of a liquid by measuring the absorbance of the liquid of interest (hereinafter also referred to as “measuring turbidity and chromaticity”). Absorbance turbidity colorimeter About.

  Conventionally, for example, in food plants that handle liquids, it is often necessary to measure the turbidity and chromaticity of the liquid. Examples of the target liquid include beer and soy sauce.

  Non-Patent Document 1 includes a transmitted light method, a transmitted scattered light method, a surface scattered light method, an integrating sphere method, and the like as a turbidimeter method. Among them, a transmitted light technique describes a method of measuring turbidity with light having a wavelength of 660 nm (nanometers). In general, as a transmitted and scattered light type technique, a method is known in which light scattered by turbidity contained in a liquid is detected and a ratio to transmitted light is measured.

  Further, Non-Patent Document 1 describes a method of converting the absorbance of light having a wavelength of 390 nm into chromaticity as a transmitted light technique with respect to a chromaticity meter method.

  Further, Patent Document 1 discloses that light to be measured and reference water are alternately passed through a measurement cell at predetermined intervals, light having a predetermined wavelength is irradiated from the light source into the measurement cell, and light that has passed through the measurement cell. A technique for measuring the turbidity and chromaticity of water to be measured by detecting water is described.

Japanese Patent No. 4232361

Japan Water Works Association, “Water test method 2011 version”, 2011

  However, the above-described conventional technology has the following problems. For example, when a tungsten lamp is used as the light source, the filament breaks and suddenly becomes unusable, or the metal component of the filament volatilizes over a long period of time and adheres to the inner surface of the lamp, causing deterioration. As a result, the emission intensity may be reduced, affecting the measurement. Therefore, maintenance work such as periodic light source replacement is required.

  In addition, since light having various wavelengths exists in the light emitted from the tungsten lamp, a spectroscope for obtaining light having a wavelength in a specific region is necessary. In the spectroscope, filter elements such as filter type, prism type, and diffraction grating type are used depending on the type of disperser that chooses monochromatic light from the light source (white light), but vibrations occur because glass optical parts are included. Since there is a possibility that it may be broken by an impact and the structure tends to be complicated, regular adjustment and maintenance are required for use in long-term continuous measurement.

  Moreover, in the above-described conventional technology, it is difficult to directly attach to the pipe through which the liquid flows from the viewpoint of the size of the light source and attached optical components, the weight of the power source, and the like. Therefore, for example, a part of the liquid is collected using a branch pipe for measurement, and the turbidity and chromaticity of the liquid is measured with a detector installed at the collection place. There is a problem that costs are high. In addition, when the branch pipe is used, there is a problem that a time difference between the time of liquid collection and the time of measurement occurs, and the real time property of the measurement is impaired. In addition, there is a problem that it takes time and cost to discard the collected liquid.

  Therefore, the present invention has been made in view of such circumstances, and it is an object of the present invention to provide a turbidity colorimeter that can realize real-time performance at low cost with low necessity for maintenance work.

In order to solve the above-described problems, the present invention provides a first semiconductor light emitting device that irradiates a liquid to be measured with light of a first wavelength, and a second semiconductor that irradiates the liquid with light of a second wavelength. Irradiated by a light emitting element, a first optical sensor that receives light of the first wavelength that has been irradiated by the first semiconductor light emitting element and transmitted through the liquid, and converts it into an electrical signal, and irradiated by the second semiconductor light emitting element A second optical sensor that receives light of the second wavelength transmitted through the liquid and converts it into an electrical signal, and calculates the turbidity of the liquid based on the electrical signal from the first optical sensor; A turbidity colorimeter, comprising: a processing unit that calculates chromaticity of the liquid based on an electrical signal from the second optical sensor.
Other means will be described later.

  According to the present invention, it is possible to provide a turbidity colorimeter capable of realizing real-time performance at low cost with low necessity for maintenance work.

It is a whole block diagram of the turbidity colorimeter of this embodiment. It is explanatory drawing, such as a structure of the detector in the turbidity colorimeter of this embodiment. It is a flowchart which shows the flow of a process in the turbidity colorimeter of this embodiment. It is explanatory drawing of the other structural example of the detector in the turbidity colorimeter of this embodiment. It is explanatory drawing of the other use of the turbidity colorimeter of this embodiment.

  Hereinafter, a form for implementing the turbidity colorimeter of the present invention (hereinafter referred to as “embodiment”) will be described with reference to the drawings. As shown in FIG. 1, the turbidity colorimeter 100 includes a detector 10, a fixture 20, a processing device 30 (processing unit), and a converter 50.

The detector 10 is inserted into the pipe 40 through a through-hole provided in advance on the side wall of the pipe 40 through which the liquid flows, and is fixed to the pipe 40 by a detachable fixing device 20 such as a flange or a sanitary clamp.
The fixing device 20 is a device for fixing the detector 10 to the pipe 40.

The processing device 30 processes the information obtained by the detector 10 and transmits the processed information to the converter 50 (details will be described later).
The converter 50 converts the information obtained from the processing device 30 into a current value or a voltage value, and outputs it to an external monitor (not shown) or the like (details will be described later).

Next, the structure and the like of the detector 10 in the turbidity colorimeter 100 will be described with reference to FIG.
The detector 10 includes LEDs (Light Emitting Diodes) 1a and 1b (hereinafter referred to as “LED1” unless the two are particularly distinguished. The same applies to other configurations), glass windows 2a and 2b, and optical sensors 3a and 3b. The glass windows 8a and 8b are provided, and the whole is substantially U-shaped, and is inserted into and fixed to the inside of the pipe 40 (the space in which the liquid exists). The O-ring 21 is a means for preventing the liquid in the pipe 40 from leaking outside through the through hole.

LED1a (1st semiconductor light-emitting device) irradiates the liquid of a measuring object with the light of 1st wavelength (for example, 660 nm).
The LED 1b (second semiconductor light emitting element) irradiates the liquid to be measured with light having a second wavelength (for example, 390 nm).
The glass windows 2a and 2b are provided at positions on the light passing path in the vicinity of the light emitting portions of the LEDs 1a and 1b, respectively. The material of the glass window 2 is, for example, quartz glass.

The optical sensor 3a (first optical sensor) is provided at a position facing the LED 1a, receives light of the first wavelength emitted from the LED 1a and transmitted through the liquid, and receives analog electric light according to the intensity of the light. Generate a signal.
The optical sensor 3b (second optical sensor) is provided at a position facing the LED 1b, receives light of the second wavelength emitted from the LED 1b and transmitted through the liquid, and receives analog electric light according to the intensity of the light. Generate a signal. The optical sensor 3b may receive light of the first wavelength emitted from the LED 1a and scattered by the liquid and generate an analog electrical signal corresponding to the intensity of the light.
The optical sensor 3 can be realized by, for example, a Si photodiode, a photoelectron tube, a CdS conductive cell, a CCD (Charge Coupled Device), or the like.

The glass windows 8a and 8b are provided at positions on the light passage in the vicinity of the optical sensors 3a and 3b, respectively. The material of the glass window 8 is, for example, quartz glass.
Note that the distance from the LED 1 to the optical sensor 3 may be set such that, for example, the absorbance of the liquid to be measured is about 0.5 to 3 from the viewpoint of measurement accuracy.

The processing device 30 includes a detection circuit 31, a controller 32 (processing unit), and an output device 33.
The detection circuit 31 receives electrical signals from the optical sensors 3a and 3b, generates digital signals corresponding to these electrical signals, and sends them to the controller 32.

The controller 32 includes, for example, a CPU (Central Processing Unit) and a memory. The controller 32 gives a light emission instruction to the LED 1 and calculates the turbidity and chromaticity of the liquid based on the digital signal received from the detection circuit 31. Are transmitted to the output device 33.
The output device 33 sends the turbidity and chromaticity information of the liquid received from the controller 32 to the converter 50.

  Next, the operation of the turbidity colorimeter 100 will be described. First, the controller 32 controls the timing of light emission by each of the LEDs 1a and 1b. In the detection circuit 31, the “lighting of the LED 1 a, 1 b”, “lighting of the LED 1 a, turning off the LED 1 b”, “lighting off the LED 1 a, turning on the LED 1 b”, and “lighting off the LED 1 a, 1 b” are performed. Receive electrical signals from one or both (details below).

  The detection circuit 31 amplifies the electrical signal received from the optical sensor 3 and converts it into a digital signal. The controller 32 stores the digital signal received from the detection circuit 31 in a memory (not shown), performs numerical calculation processing according to a calculation processing procedure stored in advance in a non-volatile storage device (not shown), and generates turbidity values and colors. Calculate the degree value. The output device 33 receives the turbidity value and the chromaticity value from the controller 32 and sends them to the converter 50. The converter 50 then converts, for example, the turbidity value and the chromaticity value into an analog electric signal in the range of 4 to 20 mA, and transmits the analog electric signal to a receiving device (not shown, monitor or the like).

  Next, the arithmetic processing performed by the controller 32 will be described with reference to FIG. The controller 32 converts the following electrical signal as a reference into a digital signal in advance and stores the data in a nonvolatile storage device.

The electrical signal (Z1) of the optical sensor 3a when the LED 1a is lit when the zero point reference liquid (for example, fresh water) is flowing (S31)
The electrical signal (Z1 ′) of the optical sensor 3b when the LED 1b is lit when the zero point reference liquid is flowing (S37)
The electrical signal (Z2) of the optical sensor 3b when the LED 1a is lit when the zero point reference liquid is flowing (S43)
The electrical signal (T0) of the optical sensor 3a when the LED 1a and the LED 1b are turned off when nothing is flowing (S36)
The electrical signal (T0 ′) of the optical sensor 3b when the LED 1a and the LED 1b are turned off when nothing is flowing (S42)

  Then, the detection circuit 31 acquires the following electrical signal, converts it into a digital signal, sends it to the controller 32, and the controller 32 stores the data in a nonvolatile storage device.

The electrical signal (T1) of the optical sensor 3a when the LED 1a is lit when the sample water (liquid to be measured) is flowing (S32)
-Electrical signal (T1 ') of the optical sensor 3b when the LED 1b is lit when the sample water is flowing (S38)
-Electrical signal (T2) of the optical sensor 3b when the LED 1a is lit when the sample water is flowing (S44)

Then, the controller 32 calculates a turbidity value (TB) and a chromaticity value (C) of the liquid based on the digital signal obtained by converting the electrical signal.
More specifically, the transmitted light turbidity value is calculated as follows. First, A1 is calculated by the following formula 1 (S33), the turbidity value (TB) is calculated by the following formula 2 using the calculated A1 (S34), and the calculated turbidity value (TB) is calculated. The data is output to the output device 33 (S35).

A1 = −log {(T1−T0) / (Z1−T0)} (1)
TB = K · A1 (2)
In addition, the logarithm (log) in Formula (1) is a common logarithm (the logarithm whose base is "10") (the following other logarithms are also the same).
In addition, the coefficient K in the equation (2) is obtained in advance by an experiment (similar to S32) using a predetermined turbidity reference liquid (liquid having a known turbidity) and stored in a nonvolatile storage device. it can.

  The calculation of the chromaticity value of the transmitted light type is performed as follows. First, A1 ′ is calculated by the following equation (3) (S39), the chromaticity value (C) is calculated by the following equation (4) using the calculated A1 ′ (S40), and the calculated color The degree value (C) is output to the output device 33 (S41).

A1 ′ = − log {(T1′−T0 ′) / (Z1′−T0 ′)} (3)
C = K ′ · A1′−K ″ · A1 (4)
Note that the coefficient K ′ and the coefficient K ″ in the equation (4) are obtained in advance by an experiment (similar to S38) using a predetermined chromaticity reference liquid (liquid having a known chromaticity) and stored in the nonvolatile memory device. Can be saved.

  Further, the calculation of the turbidity value of the transmitted scattered light type is performed as follows. The chromaticity value (C) is calculated by the following equation (5) (S45), and the calculated chromaticity value (C) is output to the output device 33 (S35).

TB = K ′ ″ · (T2−Z2) / (T1−Z1) (5)
The coefficient K ′ ″ in equation (5) can be obtained in advance by an experiment using a predetermined turbidity reference solution (similar to S44) and stored in a nonvolatile storage device.
In S46, the calculation of turbidity in S33 and S34 and the calculation of turbidity in S45 can be switched as appropriate according to the use conditions and the like.

  Thus, according to the turbidity colorimeter 100, since the light emitting diode (LED 1) having a small size, light weight and long life is used as a light source, the necessity for maintenance work is low, a spectroscope is not required, It is possible to provide a turbidity colorimeter that can be directly attached to existing pipes and storage tanks, and can ensure cost reduction and real-time measurement.

  In addition, two LEDs 1 and two optical sensors 3 are used, and the turbidity is calculated by separately using the transmitted light method and the transmitted scattered light method, thereby enabling highly accurate calculation.

  Next, a modified example of the detector 10 will be described. As shown in FIG. 4, in the detector 10 a (10) as a modification, the line connecting the LED 1 and the optical sensor 3 is perpendicular to the insertion direction of the detector 10 a with respect to the pipe 40. In addition, the LED1, the glass window 2, the optical sensor 3, and the glass window 8 shall have two each like the case of FIG.

  Thus, by shortening the depth of the detector 10a inserted into the pipe 40, it is possible to reduce the possibility of solid matter (foreign matter or the like) in the liquid being entangled with the detector 10a.

  Next, other uses of the turbidity colorimeter 100 will be described. As shown in FIG. 5, the storage tank 60 stores liquids in which an upper layer and a lower layer having different turbidity and chromaticity are separated by an interface 61. The detector 10, the fixture 20, and the processing device 30 in the turbidity colorimeter 100 a (100) are attached to the side surface of the interface 61.

  Then, since the turbidity and chromaticity measured by the detector 10 and the processing device 30 differ depending on whether the interface 61 is above or below the detector 10, the turbidity and chromaticity are measured by the detector 10 and the processing device 30. Thus, when drainage is performed from the interface 61, it can be known whether the interface 61 is above or below the detector 10.

Although description of this embodiment is finished above, the aspect of the present invention is not limited to these.
For example, as the wavelength of the LED 1, in addition to the wavelength described above, the wavelength of light in the ultraviolet to far infrared region can be appropriately selected according to the absorption wavelength of the liquid to be measured. In that case, light of another wavelength can be used by replacing the LED 1. Based on the absorbance, a concentration other than turbidity and chromaticity can be calculated.

  Further, the material of the glass window 2 and the glass window 8 is not limited to quartz glass, and satisfies the conditions that the LED 1 does not absorb light more than a certain level, is resistant to a predetermined temperature and pressure, and is not easily corroded. For example, sapphire glass or a transparent polymer resin material may be used.

Moreover, the number of parts in the turbidity colorimeter 100 can be reduced by using a device in which a plurality of LEDs 1 are packaged into one instead of the plurality of LEDs 1.
Moreover, as a method of installing the turbidity colorimeter 100 in the pipe 40, in addition to a method of installing a hole in the pipe 40, a method of installing it in a branch pipe of a T-shaped tube or a method of installing it in a fire hydrant. is there.
In addition, about a concrete structure, it can change suitably in the range which does not deviate from the main point of this invention.

1,1a, 1b LED
2, 2a, 2b Glass window 3, 3a, 3b Optical sensor 8, 8a, 8b Glass window 10, 10a Detector 20 Fixing device 30 Processing device 31 Detection circuit 32 Controller 33 Output device 40 Piping 41 Liquid 50 Converter 60 Storage tank 61 Interface 100, 100a Turbidity Colorimeter

Claims (4)

A first semiconductor light emitting element that irradiates a liquid to be measured with light of a first wavelength;
A second semiconductor light emitting device for irradiating the liquid with light of a second wavelength;
A first optical sensor that receives light of the first wavelength irradiated by the first semiconductor light emitting element and transmitted through the liquid and converts the light into an electrical signal;
A second optical sensor that receives the light of the second wavelength that has been irradiated by the second semiconductor light emitting element and transmitted through the liquid, and converts the light into an electrical signal;
A processing unit that calculates turbidity of the liquid based on an electrical signal from the first photosensor, and calculates chromaticity of the liquid based on an electrical signal from the second photosensor;
A turbidity colorimeter characterized by comprising:   2. The turbidity colorimeter according to claim 1, wherein the first semiconductor light emitting element and the second semiconductor light emitting element are LEDs (Light Emitting Diodes). The second optical sensor receives light of the first wavelength irradiated by the first semiconductor light emitting element and transmitted through the liquid, and converts it into an electrical signal,
The processor is
An electrical signal from the first sensor; and
The turbidity of the liquid is calculated based on an electrical signal from the second photosensor that has received light of the first wavelength that has been irradiated by the first semiconductor light emitting element and transmitted through the liquid. The turbidity color clock according to claim 1 or 2.   The detector configured by the first semiconductor light emitting element and the second semiconductor light emitting element, and the first optical sensor and the second optical sensor facing each other is disposed in a space where the liquid exists. The turbidity colorimeter according to any one of claims 1 to 3, wherein the turbidity colorimeter is inserted and fixed to the turbidity colorimeter.

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