JPH10318920A - Method and apparatus for measuring fluid concentration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate measuring errors thereby enabling a more correct measurement, by setting measuring points of preliminarily set two different measuring distance, and obtaining a concentration of a fluid from an intensity of a penetration radiation flux at each measuring point and the measuring distance. SOLUTION: A passage 1 for a fluid 2 to be measured is branched to passages 61, 71 of different diameters. Transmission glass members 12, 22 sectioning the passages from the outside and passing measuring lights 11, 21 therethrough are provided at the passages, respectively. Light-emitting detecting systems 10, 20 comprising light- emitting sources 13, 23 and light-detecting sensors 14, 24 are set respectively at a first and a second measuring points where a thickness of a glass layer between the transmission glass members 12, 22 (measuring distance) is X1 , X2 . A concentration of the fluid at the first, second measuring point is obtained by an operation from an intensity I1 , I2 of a penetrating radiation flux measured by the light-detecting sensor 14, 24, and a concentration of the fluid per unit measuring distance is obtained from the above concentration and the measuring distance X1 , X2 . An attenuation, a change of the intensity of the penetrating radiation flux resulting from the other factor than the fluid to be measured is eliminated, whereby a correct transmission concentration can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the concentration of a fluid based on a change in the intensity of a light beam emitted from radiation such as visible light, ultraviolet light, infrared light, .beta. The present invention relates to a method and apparatus for measuring a fluid concentration. More specifically, for example, a device for measuring dust concentration in flue gas, a device for measuring liquid turbidity such as dam water, tank water, industrial effluent, domestic effluent, and a reaction solution or culture solution in the production process of chemical substances and biological products -A device for measuring a flux transmission concentration of a fermentation liquid or the like is a device that measures the concentration of a fluid using visible light. In addition, there is an apparatus for analyzing and measuring the concentration of a fluid using a radiation flux having a radiation source other than visible light, such as ultraviolet rays, infrared rays, β rays, and other energy rays as a measurement medium. The present invention relates to a method and an apparatus for measuring the concentration of a fluid for measuring the concentration of a fluid from a change in intensity when a flux from these sources permeates a fluid.

[0002]

2. Description of the Related Art An apparatus for measuring a fluid concentration based on flux transmission requires a radiation source, a flux intensity sensor, and a transmission partition member interposed therebetween for partitioning a fluid to be measured. A change in flux transmittance due to dirt or the like results in a measurement error, which is an obstacle to continuous measurement. However, when the flux (light) transmission density of a fluid is measured discontinuously in a laboratory, before and after housing the fluid to be measured in a container such as a shell or column that transmits the measurement flux (light). By measuring the transmittance, measurement errors can be eliminated.

For example, in a conventional apparatus for measuring the concentration by transmitting light to exhaust gas, a method is employed in which clean air is supplied to a gas side surface of a permeation partition member to prevent contact with a non-measurement gas.

Conventionally, there has been proposed an apparatus based on the principle of using a plurality of beam slitters as a member for partitioning a fluid in an exhaust gas light transmission concentration measuring apparatus and calculating and correcting dirt attached to a gas contact surface thereof. I have.

In a conventional turbidimeter, which is a light transmission measuring device, a product in which ultrasonic vibration is applied to a plate glass, which is a partition transmission member, to remove dirt on the glass surface, and dirt is prevented from being attached. There are examples of products being marketed.

[0006]

In the method of supplying clean air, dirt cannot be completely prevented, so frequent and regular cleaning is required. A change in the transmittance of the member itself cannot be excluded.

In the device based on the principle of calculating and correcting dirt, the configuration of the optical system and the calculation formula are complicated, the price of the optical member is expensive, and the calculation error is unavoidable.

[0008] The effect of ultrasonic vibration applied to a product to prevent dirt from adhering is not as expected.
There has been a problem that frequent and regular cleaning of the glass surface is required.

In the apparatus for measuring the flux transmittance concentration of a fluid,
In order to wash the permeate partition member, the measurement must be interrupted during that time, and in the case of a non-sampling flue gas light transmission concentration measurement device in continuous operation equipment, the zero point after cleaning the permeate partition member There is a problem that adjustment and span adjustment cannot be performed unless the operation of the equipment is stopped.

An object of the present invention is to provide a fluid concentration measuring device capable of eliminating measurement errors and performing more accurate measurement.

Another object of the present invention is to provide a fluid concentration measuring apparatus in which the frequency required for cleaning the surface of the partition member, the frequency for interrupting the measurement, and the frequency for interrupting the operation of the target equipment are reduced as much as possible. It is to be.

Still another object of the present invention is to provide a fluid concentration measuring device which reduces labor required for cleaning the surface of a partition member and saves labor.

[0013]

SUMMARY OF THE INVENTION According to the present invention, a flux from a radiation source is transmitted through a fluid to be measured, and the transmitted flux intensity I ₁ , I ₂
Is detected by a flux intensity sensor, and the flux intensity is attenuated in accordance with the flux transmittance of the fluid to be measured. Setting a second measurement point with two different measurement distances X ₁ and X ₂ set in advance, and measuring the respective transmission flux intensities I ₁ and I ₂ at the first and second measurement points, one of these transmitted flux intensity I _1, I ₂ is divided by the other hand, the division value by logarithmic arithmetic, to obtain a first, fluid concentration in the second measurement point, the measured distance X ₁ , X ₂ , and the other is subtracted from the other, and the reciprocal of the subtraction value is calculated. The fluid concentration values at the first and second measurement points and the measurement distance X ₁ ,
First by multiplying the reciprocal value of the subtraction value of X _2, consists of a step of determining a fluid density of the unit measurement distance in the second measurement point, the transmission line bundle strength due to causes other than the fluid to be measured attenuation and / or change The fluid concentration measuring method is characterized in that the concentration of the fluid is measured by removing the fluid concentration.

In measuring the flux transmission density, two different
The flux transmission intensity is obtained at the two measurement distances X ₁ and X ₂ , the both measurement distances are given, and the correction is performed based on the correction operation formula, thereby eliminating the transmittance change due to the contamination of the transmission partition member and the like. An accurate flux transmission density of the measurement fluid can be obtained.

In measuring the flux transmission density of the same fluid, two sets of flux transmission density measuring systems comprising a source and a flux intensity sensor are provided, and the thickness of the fluid to be measured through which both fluxes are transmitted is arbitrarily defined. By arranging in different dimensions,
The flux transmission density at two different measurement distances is determined.

When measuring the flux transmission density of the fluid, a set of flux transmission density measuring systems comprising a source and a flux intensity sensor is provided, and the distance between the source and the flux intensity sensor or the flux transmission of the fluid to be measured is provided. It is also possible to determine the flux transmission density at two different measurement distances by mechanically changing the thickness of the portion to two dimensions that are arbitrarily defined.

The radiation source as the measurement medium is not limited to visible light, but may be ultraviolet light,
Light sources such as infrared rays, radiation such as β-rays, and other energy rays can be used as the radiation source.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fluid concentration measuring device according to the present invention will be described with reference to the drawings. Hereinafter, a case where the fluid to be measured is a gas and the radiation source as the measurement medium is visible light will be described as an example. FIG. 1 is a view for explaining the principle of the correction operation of the present invention. A flow path 1 of a fluid to be measured (hereinafter, referred to as a gas to be measured) 2 has flow paths 61 and 71 having different diameters in the middle. The transparent glass members 12 and 22 as the partition members that allow the light fluxes (hereinafter, referred to as measurement light) 11 and 21 to pass through the positions of the flow paths 61 and 71 and partition the flow paths 61 and 71 from the outside. Are provided at the positions of the transmission glass members 12 and 22, respectively, and a flux transmission density measurement system (hereinafter, referred to as first and second projection / reception systems) 10 and 20 are provided. The first light emitting / receiving system 10 includes a first light source (hereinafter, referred to as a first light emitting source) 13 and a first flux intensity sensor (hereinafter, referred to as a first light receiving sensor) 14 and corresponds thereto. Let X _{1 be} the thickness of the two layers of the gas to be measured between the transmission glass members 12 on both sides. The second light emitting / receiving system 20
Is composed of a second radiation source (hereinafter, referred to as a second light source) 23 and a second flux intensity sensor (hereinafter, referred to as a second light receiving sensor) 24. the thickness of the measurement gas 2 layers and X _2.

Hereinafter, the position of the first light emitting / receiving system 10 will be referred to as a first measurement point, and the position of the second light emitting / receiving system 20 will be referred to as a second position.
As measurement points, the thicknesses X ₁ and X ₂ of the measured gas 2 through which the respective measurement lights 11 and 21 pass are referred to as measurement distances. In addition,
A first measurement point is measured distance X _1, second measurement point is measured distance X ₂ is a position different from precisely, the flow channel 1
Are set at the positions of flow paths 61 and 71 having different diameters, which are close to each other, and the respective measurement lights 11 and 21 transmit the gas 2 having the same concentration and partition the gas 2 to be measured. It is assumed that the degree of contamination and the degree of change in light transmittance of the transmission glass members 12 and 22 are also the same.

In FIG. 1, X ₁ : measurement distance at the first measurement point X ₂ : measurement distance at the second measurement point α ₁ : light transmittance of gas at the first measurement point (fluid flux transmittance) α ₂ : Gas light transmittance (fluid flux transmittance) of gas at the second measurement point I ₀₁ : Light projection intensity (radiation flux intensity) at the first measurement point I ₀₂ : Light projection intensity (radiation flux intensity) of the second measurement point I _1: the first light reception intensity (transmittance flux intensity) of the measurement point I _2: received light intensity (transmittance flux intensity) of the second measurement point beta: the transmittance of the transmission glass member containing dirt

The light transmittance of the gas 2 at both the first and second measurement points is α ₁ , α ₂ , the transmittance of the transmission glass members 12, 22 on both sides including dirt is β, and the measurement beams 11, 21 are projected. Strength I
_Assuming that ₀₁ , I ₀₂ , and the received light intensity are I ₁ , I ₂ , the relationship between them is as follows: I ₁ = α ₁ · β · β · I ₀₁ = α ₁ · β ² · I ₀₁ ··· (1) I ₂ = α ₂ · β · β · I ₀₂ = α ₂ · β ² · I ₀₂ ··· 2) By taking the reciprocal of the light transmittance of the measured gas 2 at the first and second measurement points from the equations (1) and (2), the following equation (3) is obtained.
Equation (4) is obtained. 1 / α ₁ = (I ₀₁ / I ₁ ) · β ² (3) 1 / α ₂ = (I ₀₂ / I ₂ ) · β ² (4)

[0022] Taking the log ₁₀ of the reciprocal of where the gas permeability, the first measurement point by definition, the optical density (Optical Density) at the second measurement point. log ₁₀ (1 / α ₁ ) = log ₁₀ {(I ₀₁ / I ₁ ) · β ² } (5) log ₁₀ (1 / α ₂ ) = log ₁₀ {(I ₀₂ / I ₂ ) · β ² } (6) By transforming both formulas (5) and (6) and subtracting the other formula from one formula, the translucent glass members 12, 2
2 disappears as follows.

The optical density at both the first and second measurement points is
Since they are the same gas, if they are converted into optical densities at a unit measurement distance based on Lambert-Beer's law, they have the same value, and the following equation (8) holds. (1 / X ₁ ) · log ₁₀ (1 / α ₁ ) = (1 / X ₂ ) · log ₁₀ (1 / α ₂ ) (8) When the optical density at the second measurement point is obtained by shifting the terms, log ₁₀ (1 / α ₂ ) = (X ₂ / X ₁ ) · log ₁₀ (1 / α ₁ ) (9) Obtain the obtained optical density {log ₁₀ (1 / α ₂ )} of the second measurement point. Substituting into the above equation (7), log ₁₀ (1 / α ₂ ) −log ₁₀ (1 / α ₁ ) = (X ₂ / X ₁ ) · log ₁₀ (1 / α ₁ ) −log ₁₀ (1 / α ₁ ) = (X ₂ / X ₁ −1) · log ₁₀ (1 / α ₁ ) = (X ₂ −X ₁ ) · {(1 / X ₁ ) · log ₁₀ (1 / α ₁ )} (10) {(1 / X ₁ ) · log ₁₀ (1 /
The term α ₁ )} is the optical density of the unit measurement distance at the first measurement point, and is (1 / X ₁ ) · log ₁₀ (1 / α ₁ ) = {1 / (X ₂ −X ₁ )} · { log ₁₀ (1 / α ₂ ) −log ₁₀ (1 / α ₁ )} = {1 / (X ₂ −X ₁ )} · {log ₁₀ (1 / α ₂ ) / (1 / α ₁ )} = { 1 / (X ₂ −X ₁ )} · log ₁₀ {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ )} (11) That is, the projected and received light amounts at both the first and second measurement points. (I
₀₂ , I ₂ , I ₀₁ , I ₁ ) and the respective measurement distances X ₁ , X ₂
Is given, the transmission glass member 12,
The optical density {(1 / X ₁ ) · log ₁₀ (1 / α ₁ )} at the unit measurement distance of the measured gas 2 from which the term of the transmittance β of 22 is deleted is obtained.

In the above equation (11), if the two light emitting intensities I ₀₁ and I ₀₂ are the same, they are removed and simplified as in the following equation (11 ′). (1 / X ₁ ) · log ₁₀ (1 / α ₁ ) = {1 / (X ₂ −X ₁ )} · log ₁₀ (I ₁ / I ₂ )} (11 ′) Equation (8) As is clear from FIG. 7, the optical densities of the unit measurement distances at the first and second measurement points are the same.

In the above equation, the common logarithm is adopted from the definition of the optical density, but the result is the same even if this is replaced with a natural logarithm.

Further, the same result can be obtained even if the procedure of the calculation from the equations (3) to (7) is changed, for example, from the following equations (12) to (14). α ₁ / α ₂ = (I ₀₂ / I ₂ ) · {1 / (I ₀₁ / I ₁ )} (13) Thereafter, when a logarithm is taken, log ₁₀ (1 / α ₂ ) −log ₁₀ (1 / Α ₁ ) = log ₁₀ (I ₀₂ / I ₂ ) −log ₁₀ (I ₀₁ / I ₁ ) (14), and the expression (14) gives the same result as the operation of the expression (7). Can be

Further, other operations will be described. According to Lambert-Beer's law, (1 / α ₁ ) ^{(1 / X 1)} = (1 / α ₂ ) ^{(1 / X 2)} (15) Therefore, this equation (15) is transformed into the following equation (16).
Get the expression. 1 / α ₂ = (1 / α ₁ ) ^{(X2 / X1)} = 1 / α ₁ ^{(X2 / X1)} (16) This equation (16) is divided by the left side and the right side of the basic equation to obtain a β term. Clearing the (12) alpha ₂ is substituted into the equation to _{erase, α 1 / α 2 = (} I 1 / I 2) · (I 02 / I 01) = (I 02 / I 2) · {1 / (I ₀₁ / I ₁ )｝ = α ₁ · (1 / α ₁ ) ^{(X2 / X1)} = α ₁ · (1 / α ₁ ^{(X2 / X1)} ) = α ₁ ^{(X1 / X2)} · α ₁ ^{- (X2 / X1)) =} α 1 (X1-X2) / X1 = (1 / α ₁ ) ^{(X2-X1) / X1} = ｛(1 / α ₁ ) ^{1 / X1} ｝ ^X2-X1 (17) By transposing, (1 / α ₁ ) ^{1 / X1} = ｛(I ₀₂ / I ₀₁ ) / (I ₀₁ / I ₁ )｝ ^{1 / (X2-X1)} ... (18) Take the logarithm (1 / X ₁ ) · log ₁₀ (1 / α ₁ ) = {1/1 / X ₂ −X ₁ )} · log ₁₀ {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ )} (19) As described above, the same operation is performed by a different calculation procedure.

There are other arithmetic expressions and procedures that make the results equivalent, but "the respective flux transmittances obtained at two different measurement distances and the two measurement distances are given as inputs, and the gas to be measured is given. The calculations for obtaining the flux transmission density from which the attenuation and / or change in the transmission binding strength due to other factors are removed are all equivalent.

FIG. 2 shows one side of the flow path 1 (61, 71).
On the left side in the figure, first and second light sources 13 and 23, first and second beam splitters 16 and 26, and first and second light receiving sensors 14 and 24 are provided together. (Right side)
By providing the first and second reflectors 15, 25,
FIG. 7 is a diagram for explaining correction calculation in the case of two first and second light projecting / receiving systems 10 and 20 of a so-called double beam system in which measurement beams 11 and 21 reciprocate in a gas 2 to be measured. The first and second beam slitters 1 in the figure
6 and 26 transmit the total luminous flux from the first and second light projecting light sources 13 and 23 to the first and second reflectors 15 and 25, and return the reflected light to the first and second light receiving sensors 14 and 24 is an optical member that totally reflects light to the light.

The light transmittance of the gas to be measured 2 at the first measurement point and the second measurement point is represented by α ₁ and α ₂ , and the first and second transmission glass members 12 and 22 disposed in the measurement optical path are cleaned. Is the transmittance including β, and the reflectance of the first and second reflectors 15 and 25 is γ.
₁₁ , γ ₂₁ , the transmission and reflectance of the first and second beam slitters 16 and 26 are γ ₁₂ and γ ₂₂ , the projection intensity of the measurement light is I ₀₁ ,
_Assuming that I ₀₂ and the received light intensity are I ₁ and I ₂ , the relationship between them is given by the following equations (20) and (21). ^{_{I 1 = α 1 2 · β}} 4 · γ 11 · γ 12 · I 01 ...... (20) I 2 = α 2 2 · β 4 · γ 21 · γ 22 · I 02 ...... (21) first, Taking the reciprocal of the light transmittance of the measurement gas 2 when the measuring light travels back and forth in the two-car measuring ^{_{points, 1 / α 1 2 = (}} I 01 / I 1) · β 4 · γ 11 · γ 12 ...... (22) 1 / α ₂ ² = (I ₀₂ / I ₂ ) · β ⁴ · γ ₂₁ · γ ₂₂ (23)

[0031] Taking the log ₁₀ of the reciprocal of where the gas permeability, the first measurement point by definition, the optical density (Optical Density) at the second measurement point. log ₁₀ (1 / α ₁ ² ) = log ₁₀ {(I ₀₁ / I ₁ ) · β ⁴ · γ ₁₁ · γ ₁₂ } (24) log ₁₀ (1 / α ₂ ² ) = log ₁₀ {(I ^{_{02 / I 2) · β 4}} · γ 21 · γ 22} ...... (25) γ 11 = γ 21, as gamma ₁₂ = gamma _22, by modifying the (24) (25) both equations, is subtracted, transmitting glass The transmittance β including contamination of the members 12 and 22 and the reflectance γ ₁₁ · γ of the first and second reflectors 15 and 25 and the first and second beam slitters 16 and 26.
₂₁ · γ ₁₂ · γ ₂₂ vanishes as in the following equation (26).

The optical density at both the first and second measurement points is:
Since they are the same gas, if they are converted into optical densities at a unit measurement distance, they both have the same value, and the following equation (27) holds. {1 / (2 · X ₁ )} · log ₁₀ (1 / α ₁ ² ) = {1 / (2 · X ₂ )} · log ₁₀ (1 / α ₂ ² ) (27) When obtaining the optical density of the measurement gas 2 at the second measurement _{point, log 10 (1 / α 2} 2) = (X 2 / X 1) · log 10 (1 / α 1 2) ...... (28) the second measurement The optical density of the point {log ₁₀ (1 / α ₂ ² )} is
By substituting into the equation (8), log ₁₀ (1 / α ₂ ² ) −log ₁₀ (1 / α ₁ ² ) = (X ₂ / X ₁ ) · log ₁₀ (1 / α ₁ ² ) −log ₁₀ (1 / α ₁ ² ) = (X ₂ / X ₁ −1) · log ₁₀ (1 / α ₁ ² ) = 2 · (X ₂ −X ₁ ) · {1 / (2 · X ₁ )} · log ₁₀ (1 / Α ₁ ² ) …… (29)

In the equation (29), {(1 / (2 ·
X ₁ )} · log ₁₀ (1 / α ₁ ² )} is the optical density of the unit measurement distance at the first measurement point, and is expressed as {1 / (2 · X ₁ )} · log ₁₀ (1 / α) ₁ ² ) = [1 / {2 · (X ₂ −X ₁ )}] · {log ₁₀ (1 / α ₂ ² ) −log ₁₀ (1 / α ₁ ² )} = [1 / {2 · (X ₂ −X ₁ )}] · log ₁₀ {(1 / α ₂ ² ) / (1 / α ₁ ² )} = [1 / {2 · (X ₂ −X ₁ )}] · log ₁₀ {(I ₀₂ / I ₂ ) ² / (I ₀₁ / I ₁ ) ² } = [1 / {2 · (X ₂ −X ₁ )}] · log ₁₀ {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ ) } ² = [1 / {2 · (X ₂ −X ₁ )}] · 2 · log ₁₀ {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ )} = {1 / (X ₂ −X ₁ )} Log ₁₀ {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ )} (30), and the expression (30) is completely the same as the expression (11). In this equation (30), if the projected and received light amounts (I ₀₂ , I ₂ , I ₀₁ , I ₁ ) at the first and second measurement points and the respective measurement distances X ₂ , X ₁ are given, the first , The transmittance β of the second transmission glass members 12 and 22 including dirt, the first and second reflectors 15 and 25, and the first and second beam slitters 16,
The optical density [{1/1/2] of the measured gas 2 at the unit measurement distance from which the terms of the reflectivity (γ ₁₁ , γ ₂₁ , γ ₁₂ , γ ₂₂ ) of 26 are deleted
(2 · X ₁ )} · log ₁₀ (1 / α ₁ ² )].

FIG. 3 shows the first and second reflectors 15 and 15 in the fluid transmittance measurement of the double beam system described in FIG.
The first and second transmission glass members 12 and 22 on the 25 side are omitted, and the first and second reflectors 15 and 25 are provided with a function of partitioning the gas to be measured 2 so as to directly contact the gas to be measured. FIG. 9 is a diagram for explaining a correction operation expression in the case. Since the first and second reflectors 15 and 25 come into contact with the gas to be measured 2 and become contaminated, their reflectivities (γ ₁₁ ) and (γ ₂₁ ) change, but they are arranged close to each other. Therefore, the degree of change in reflectance may be the same.

The gas 2 to be measured at both the first and second measurement points
Are the light transmittances α ₁ and α ₂ , the transmittance due to dirt on both sides of the light emitting and receiving devices is β, and the reflectance of the first and second reflectors 15 and 25 is γ ₁₁ , γ ₂₁ , the first and second beams. The transmission and reflectance of the liters 16 and 26 are γ ₁₂ , γ ₂₂ , the first and second measurement
Assuming that the light-emitting intensity of 1 is I ₀₁ and I ₀₂ and the light-receiving intensity is I ₁ and I ₂ , the relationship between them is as shown in the following equations (31) and (32). ^{_{I 1 = α 1 2 · β}} 2 · γ 11 · γ 12 · I 01 ...... (31) I 2 = α 2 2 · β 2 · γ 21 · γ 22 · I 02 ...... (32) That is, FIG. 2 The light transmittance of the first and second transmission glass members 12 and 22 in the process of obtaining the correction expression by the expressions (12) and (13) in the above is only changed from the fourth power to the second power. , And γ terms are all deleted, so that the same correction equation can be applied in this case as well.

Here, for the sake of simplicity, the case where visible light is used as the measurement medium has been described.
As described above, the same applies to the case where light such as ultraviolet rays and infrared rays, radiation such as β-rays, and other energy ray sources and fluxes are employed.

As described above, the flux transmittance of the same fluid 2 is measured at two measurement distances X ₁ and X ₂ , and the emission flux intensity (I ₀₁ , I _{02) at} both the first and second measurement points is measured. ) And the intensity of transmitted flux transmitted through the fluid 2 to be measured (I ₁ , I ₂ )
If the measured distances (X ₁ , X ₂ ) are obtained, the concentration [単 位 1 of the fluid 2 to be measured at a unit distance from which error factors of the optical system such as the transmittance β including the contamination of the transmission partition member are eliminated. / (2 · X ₁ )｝ · log ₁₀ (1 / α ₁ ² )] can be obtained by the correction operation expression of the present invention.

A specific embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram specifically illustrating one of the first and second light projecting / receiving systems 10 and 20 in an apparatus for measuring the light transmission concentration of a gas such as flue gas. On both sides of the position corresponding to the gas flow path 1,
Light guide tubes 5 and 6 are provided in communication with each other, and a light projector 18 is mounted on one light guide tube 5 side and a light receiver 19 is mounted on the other light guide tube 6 side. Inside the projector 18, a projection light source 13, such as a projection lamp, a condenser lens 17, and a flow path 1 are provided.
A transmission glass member 12 for airtightly partitioning the inside and outside of the device and transmitting the measurement light 11 is provided.
The light receiving sensor 14, the condenser lens 17, and the transmission glass member 12 are provided in the inside.

The projector 18 and the receiver 19 are supplied with clean air 3 respectively, and purge connection ports 52 for preventing the gas to be measured 2 from flowing into the light guide tubes 5 and 6.
53 are provided. These purge connection ports 52, 5
The clean air 3 supplied from each of the light guide tubes 3 and
And is blown into the flow channel 1, but flows along the inner wall of the flow channel 1 and is discharged according to the flow of the gas to be measured due to the small supply flow rate.

The measuring beam 11 emitted from the projector 18
Is transmitted perpendicular to the flow of the gas to be measured 2 flowing in the flow path 1 and reaches the light receiver 19, but the inside of the light guide tubes 5 and 6 is filled with clean air 3 and the measurement light 11 Does not decay. In this case, the measurement distance may be the inner diameter X of the flow path 1, and the blowing of the purged clean air 3 into the flow path 1 with the flow rate restricted to a minimum does not affect the measurement distance X. In the light emitting / receiving system in which a gas body is measured, even if the illustration is omitted in the following description, or the description in the description is omitted, the light guide tubes 5 and 6 are used unless otherwise specified. Is supplied with clean air 3.

FIG. 5 shows _two different first and _second different projecting and receiving distances X ₁ and X ₂ without changing the diameter of the gas flow path 1 to be measured in the light transmission density measurement of the gas body. Line 1
It is a figure explaining the method of installing in 0, 20. A first projecting / light receiving system 10 is arranged so as to project the measuring light 11 substantially orthogonally to the flow of the gas to be measured 2 in the flow path (1) having the same diameter whose diameter does not change on the way. 2 Emitter / receiver system 20
Are arranged so as to project the measuring light 21 at an angle inclined to the flow 2 of the gas to be measured, for example, at an inclination of 45 degrees, and to intersect with the first light projecting / receiving system 10. Then, it is possible to provide two measurement distances X ₁ and X ₂ where the distances at which the measurement light beams 11 and 21 pass through the gas to be measured are different. The method in which the first and second light-projecting / light-receiving systems 10 and 20 intersect with each other is possible even when the flow path diameters are different, but is substantially the same as in FIGS. 1, 2 and 3.
Description is omitted.

The first and second light projecting / receiving systems 1
In the case of adopting a method in which 0 and 20 intersect, depending on the properties of the dust, the first and second two light emitting / receiving systems 10,
In some cases, the influence of the scattered light component of any one of the measurement lights 20 on the other measurement light cannot be ignored. In this case, the first and second projection light beams 21 and 21 do not cross each other and are located as close as possible.
The light receiving systems 10 and 20 may be arranged.

FIG. 6 shows that, in measuring the light transmission density of a gaseous body, first and second two light emitting / receiving systems 10 and 20 having different measuring distances are installed in a gas flow path 1 having the same diameter. FIG. 4 is a diagram for explaining an example of FIG. In FIG. 6, one of the first and second two light projecting and receiving systems 10 and 20, for example, the light projecting side light guiding tube 5 and the light receiving side light guiding tube 6 in the first projecting and light receiving system 10. either one, or mounting extends both to inside the flow channel 1, the measuring light 11 to shorten the thickness X ₁ of the measurement gas 2 layer which transmits. Further, the second projecting / receiving system 20 determines the inner diameter of the flow path 1 as it is as the measurement distance X
_{Assume 2} . As a result, the first and second two light emitting / receiving systems 10 and 20 can obtain the transmittance at _two different measurement distances X ₁ and X ₂ .

In the method shown in FIG. 6, the first and second light projecting / receiving systems 10, 20 extend into the flow path 1.
Is not limited to one of the light guide tubes 5 and 6,
The light guide tubes 5 and 6 of the second two systems may be extended. In short, there is no problem if the extension dimensions are different and two different measurement distances X ₁ and X ₂ can be obtained.

FIG. 7 shows a case in which a reducing tube 8 which can move forward and backward at two positions is provided in one of, for example, the direction of the measuring optical axis of the first projecting / receiving system 10, and the measuring light is provided in the gas flow path 1 to be measured. FIG. 11 is a diagram illustrating a principle for obtaining a light transmission intensity value at two different measurement distances X ₁ and X ₂ by sequentially and automatically performing reciprocating operation with an axis center of 11 as a movement axis. The Rejushingu tube 8 may be provided in any of the projector 18 side and receiver 19 side, the measured distance when the Rejushingu tube 8 is inserted until the forward end to the exhaust gas flow path 1 and X _1, back to the retracted end the measurement distance at the time was the X _2.

In this method, the gas to be measured 2 is always filled with clean air 3 to prevent the gas to be measured 2 from entering the inside of the reducing tube 8 irrespective of the reciprocating position in the reducing tube 8. It is necessary to wait for the time for inserting the light guide and the time for filling the inside of the light guide tubes 5 and 6 with the clean air 3 to obtain the received light intensity. There is a slight problem that the result cannot be obtained as a continuous instantaneous value. A structure for automatically reciprocating the reducing tube 8;
The mechanism and its control method can be realized by applying a known technique.

In the double beam system described with reference to FIG. 3, the light transmission intensity values are measured at the first and second two light projecting / receiving systems 10 and 20 at two different measuring distances X ₁ and X ₂ . However, the present invention is not limited to this, and it is possible to obtain two positions by reciprocating one of the reflectors 15 of the first light emitting / receiving system 10 along the measurement optical axis direction in the flow path 1. Similarly, light transmission intensity values at two different measurement distances X ₁ and X ₂ can be intermittently measured by one projection / light reception system.

FIG. 8 shows the essential parts of the first and second light projecting / receiving systems 10 and 20 mounted on the waterproof housing 9 in order to measure the light transmission density of liquids such as rivers, reservoirs, water dams and reaction tanks. It is the figure which showed the structure stored. In FIG. 8, the first and second light projecting / receiving systems 10 and 20 are formed into one unit, and the light projecting unit 13 and the light projecting unit 13 are dropped by a connected cable and directly injected into the liquid 2 to be measured. 23, light receiving section 1
4 and 24 are kept airtight and the transmission glass member 1 in the measurement optical path
The liquid 2 to be measured intrudes and fills between 2 and 22 so that the light transmittance can be measured at _two different measuring distances X ₁ and X ₂ .

FIG. 9 is a block diagram illustrating the calculation method of the present invention. Since the two measurement distances are fixed values, the measurement distances X ₁ and X ₂ are given as fixed values by the measurement distance setting units 31 and 32. The electric signal of the received light intensity I ₁ corresponding to the measurement distance X ₁ is given to the first terminal 41, and the electric signal of the received light intensity I ₂ corresponding to the measurement distance X ₂ is given to the second terminal 42. In the measurement distance calculation system, the subtracter 33 subtracts the measurement distances X ₁ and X ₂ input from the measurement distance setting devices 31 and 32, and outputs a calculation output 3 thereof.
4 (X ₂ −X ₁ ) is given to the divider 35 at the next stage. The divider 35 finds the reciprocal {1 / (X ₂ −X ₁ )} and supplies the operation output 36 to the multiplier 50.

On the other hand, in the received light amount calculation system, the divider 4
3 receives _two signals I ₀₁ , I ₀₂ , I ₁ , I ₂ or received light amounts I ₁ , I ₂ , and outputs a divided value 44 of the received light amount as {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ )} or (I ₁
/ I ₂ ). Here, the case where the signals of only the _two received light amounts I ₁ and I ₂ are received means that if the _two projected light amounts I ₀₁ and I ₀₂ are the same, as described in the above equation (11 ′), This is because the light amounts I ₀₁ and I ₀₂ are erased and are unnecessary. The logarithmic calculator 45 receives the division value 44 of the received light amount and provides a logarithmic calculation output 46 to the multiplier 50. The multiplier (50) outputs {1 / (X ₂ −X ₁ )} · log as the correction operation output 51 which is the optical density value of the fluid 2 to be measured at the unit measurement distance, as expressed by the above equations (11) and (30). ₁₀ {(I ₀₂ / I ₂ ) / (I ₀₁ / I ₁ )} is output, so that the correction operation value to be obtained is obtained.

In this example, the block diagram of FIG. 9 has been described to facilitate the description of the operation process. However, the operation means may incorporate an operation program based on this principle regardless of the analog system or the digital system. It is optional to obtain the calculation result by computer,
Any of them can be realized by applying a known technique. When digital means or a computer is used as the arithmetic means, the two measurement distances X ₁ and X ₂ are fixed values, and once set, there is no need to change them at the same measurement place. Included in the program, the measurement distance values X ₁ and X ₂ or the calculation result value {1 / (X
_2- X ₁ )} is written in a predetermined register and read out whenever necessary. Further, a plurality of inputs based on the above description are given for the arithmetic expression and the arithmetic means,
The present invention is not limited to the above example as long as equivalent results can be obtained.

[0052]

According to the present invention, as described above, when measuring the luminous flux transmission density of a fluid, the luminous flux transmittance due to contamination of a permeable member that separates the fluid from the source and the luminous flux intensity sensor is measured. Fluctuations, and furthermore, fluctuations in the transmittance of the transmission member itself due to temperature changes and the like can be easily corrected by inexpensive means, and an accurate flux transmission density of the fluid can be obtained. Further, in applying the present invention, the radiation source that can be employed is not limited to visible light, and there is an advantage that the same effect can be obtained even if infrared rays, ultraviolet rays, or other energy rays are used, and its application range is wide. is there.

In measuring the flux transmission density, the flux transmission intensity is obtained at at least two different measurement distances,
In addition, by giving these measurement distances and performing correction based on the correction calculation formula, it is possible to eliminate a change in transmittance due to contamination of the transmission partition member and to obtain an accurate flux transmission density of the fluid to be measured.

In measuring the flux transmission density of the same fluid, two sets of flux transmission density measuring systems comprising a source and a flux intensity sensor were provided, and the thickness of the fluid to be measured through which both fluxes were transmitted was arbitrarily defined. By setting different dimensions, the flux transmission density at two different measurement distances can be obtained. Further, a set of a flux transmission density measuring system comprising a radiation source and a flux intensity sensor is provided, and the distance between the radiation source and the flux intensity sensor or the thickness of the measurement distance of the fluid to be measured is arbitrarily defined. It is also possible to obtain the flux transmission density at two different measurement distances by mechanically changing the dimensions to the two steps described above.

[Brief description of the drawings]

FIG. 1 is a principle explanatory view of a fluid concentration measuring device according to the present invention, in which first and second light projecting / receiving systems 10 and 20 are provided at two locations near the same flow path having different diameters, FIG. 9 is a principle explanatory diagram for obtaining and calculating transmittances at different measurement distances X ₁ and X ₂ .

FIG. 2 is a principle explanatory view of a fluid concentration measuring apparatus according to the present invention which employs a Davil beam system. First and second reflectors 10 and 20 are respectively provided with first and second reflectors. 15 and 25, and the first and second beam slitters 16 and 2 are provided.
FIG. 6 is a principle explanatory diagram for separating a received light beam by 6;

FIG. 3 is a principle explanatory diagram of a fluid concentration measuring device according to the present invention, which is a modification of the double beam system in FIG. 2,
Instead of the transmitting glass members 12 and 22 on the light receiving side, first,
FIG. 4 is a principle explanatory view in which second reflectors 15 and 25 are arranged facing a flow path 1.

FIG. 4 is a sectional view showing a first specific example of the fluid concentration measuring device according to the present invention.

FIG. 5 is a cross-sectional view showing a second specific example of the fluid concentration measuring apparatus according to the present invention. In the flow path 1 having the same diameter, two different transmission paths of the measuring lights 11 and 21 are crossed. FIG. 5 is a cross-sectional view showing an example in which two measurement distances X ₁ and X ₂ are obtained.

FIG. 6 is a cross-sectional view showing a third specific example of the fluid concentration measuring device according to the present invention, and the light guide tube 5 in one of the first and second light projecting / receiving systems 10 and 20; 6 is a sectional view showing an example in which two different measurement distances X ₁ and X ₂ are obtained by extending the inside of the flow channel 1.

FIG. 7 is a sectional view showing a fourth specific example of the fluid concentration measuring device according to the present invention, and the light guide tube in one of the first and second flux transmission density measuring systems 10 and 20; 5,
6 is a cross-sectional view showing an example in which a reducing tube 8 is provided in any one of 6 so as to be able to move forward and backward to obtain _two different measurement distances X ₁ and X ₂ .

FIG. 8 is a cross-sectional view showing a specific fifth embodiment of the fluid concentration measuring device according to the present invention.
FIG. 3 is a cross-sectional view showing an example in which first and second flux transmission density measuring systems 10 and 20 are accommodated, immersed in a fluid 2 to be measured, and a light transmission density is measured.

FIG. 9 is a block diagram for explaining the operation principle and operation procedure of the fluid concentration measuring device according to the present invention.

[Explanation of symbols]

1, 61, 71 ... flow path of the fluid to be measured, 2 ... fluid to be measured,
3: Clean air, 5, 6: Light guide tube, 8: Reducing tube, 10, 20: Radiation flux transmission density measurement system (projection / light reception system), 13, 23: Radiation source (illumination light source), 14, 24: Radiation bundle Intensity sensor (light receiving sensor), 15, 25 ... reflector, 1
6, 26: beam slitter, 17: condenser lens,
18: light emitter, 19: light receiver, 31, 32: measurement distance setting device, 33: subtractor, 35: divider, 41: light reception input terminal, 42: light reception input terminal, 43: divider, 44: division value, 45: Logarithmic operation unit, 46: Logarithmic operation output, 50: Multiplier, 51: Correction operation output, 52, 53 ... Purge connection port.

Claims (7)

[Claims] 1. A flux from a radiation source is transmitted through a fluid to be measured, a transmitted flux intensity is sensed by a flux intensity sensor, and a degree of attenuation of the transmitted flux intensity in accordance with a flux transmittance of the fluid to be measured is measured. In the fluid concentration measurement method, the first and second measurement points at the measurement position of the fluid 2 to be measured are set to two different measurement distances X ₁ set in advance,
X _2, a step of measuring the transmission flux intensity I ₁ , I ₂ at each of the first and second measurement points, and a step of measuring the transmission flux intensity I ₁ , I ₂ and the measurement distances X ₁ , X ₂ Removing the attenuation and / or change in the intensity of the transmitted light flux due to a cause other than the fluid to be measured, and measuring the fluid concentration. 2. A flux from a radiation source is transmitted through a fluid to be measured, and transmitted flux intensities I ₁ and I ₂ are detected by a flux intensity sensor.
In a fluid concentration measuring method for measuring the degree to which the flux intensity is attenuated in accordance with the flux transmittance of a fluid to be measured, first and second measurement points at the same or adjacent measurement positions of the fluid to be measured 2 are preset. The two different measurement distances X ₁ and X _{2 are} set, and the respective transmission flux intensities I ₁ and I _{1 at} these first and second measurement points are set.
Measuring I ₂ , dividing one of the transmission flux intensities I ₁ and I ₂ by the other, and performing a logarithmic operation on the divided value to obtain the fluid concentration at the first and second measurement points. A step of subtracting the other from one of the measurement distances X ₁ and X ₂ and calculating the reciprocal of the subtraction value; and a fluid concentration value at the first and second measurement points and the measurement distance X ₁ , first by multiplying the reciprocal value of the subtraction value of X _2, it consists of a step of determining a fluid density of the unit measurement distance in the second measurement point, the attenuation and / or transmitted flux intensity due to causes other than the fluid to be measured A fluid concentration measuring method, wherein a change is removed and the concentration of the fluid is measured. 3. A flux from a source on one side of a fluid to be measured is sensed by a flux intensity sensor on the other side of the fluid to be measured, and a transmitted flux intensity is measured. 3. The method according to claim 1, wherein the concentration of the fluid is measured by removing attenuation and / or change of the fluid concentration. 4. A flux from a source on one side of the fluid to be measured is reflected by a reflector on the other side of the fluid to be measured, and a measurement distance X is obtained.
_1, at least one round trip the flux between X ₂ are sensed by flux intensity sensor measures the permeation flux intensity, the concentration of the fluid to remove the decay and / or change in the transmitted flux intensity due to causes other than the fluid to be measured 3. The method according to claim 1, wherein the fluid concentration is measured. 5. A flux transmission density measuring system comprising a radiation source for emitting a flux and a flux intensity sensor for sensing the intensity of a transmitted flux passing through a fluid to be measured, and different measurement distances between the radiation source and the flux intensity sensor. X _1, measuring the distance setting means for setting a X ₂ and a preset measured distance X _1, X ₂ data and the transmission line flux by causes other than the fluid to be measured and a transmission flux intensity data detected by the flux intensity sensor A calculating means for calculating the concentration of the fluid by removing the attenuation and / or the change in the intensity; 6. The flux transmission density measurement system includes first and second flux transmission density measurement systems 10 and 20 which are independent of each other.
₁ , the source 13 and the flux intensity sensor 14 are arranged,
Said second flux transmission density measurement system 20, the fluid density measurement device according to claim 5, characterized in that with the measurement distance X ₂ formed by arranging the radiation source 23 and the flux intensity sensor 24. 7. A flux transmission density measurement system includes a set of radiation sources and a flux intensity sensor arranged at a predetermined distance, and the measurement distance setting means is adapted to correspond to different measurement distances X ₁ and X ₂ . 6. The fluid concentration measuring device according to claim 5, wherein an interval between flow paths of the fluid to be measured is provided so as to be adjustable.