JP2612449B2 - Ultrasonic concentration measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic concentration measuring device.

[Prior Art] Conventionally, liquid chromatography is used to measure each concentration (D ₁ ... D _n ) of a plurality (n) of solutes dissolved in a solvent. In liquid chromatography, the concentration of each solute can be measured by pouring a sampled solution into a column and separating and quantifying each solute.

[Problems to be Solved by the Invention] However, liquid chromatography requires complicated equipment and operation, and requires a great deal of labor and time to obtain the concentration of each solute. Further, since liquid chromatography is a sampling measurement method, for example, it is not possible to automatically measure the concentration of a drug solution online in a drug solution production line or the like.

Incidentally, Japanese Patent Application Laid-Open No. 58-77656 proposes a concentration measuring device using ultrasonic waves, but this concentration measuring device is useful only for measuring the concentration of a solution obtained by dissolving a single solute in a solvent. It is.

An object of the present invention is to reliably and easily measure the concentration of each solute in a multi-component solution obtained by dissolving a plurality of solutes in a solvent.

[Means for Solving the Problems] The present invention relates to an ultrasonic concentration measuring device for measuring each concentration (D ₁ ... D _n ) of a plurality (n) of solutes dissolved in a solvent,
An ultrasonic transmitter for transmitting ultrasonic waves to the solution to be measured, an ultrasonic receiver for receiving ultrasonic waves propagated in the solution to be measured, and a propagation speed (V) based on the propagation time and propagation distance of the ultrasonic waves. ), A temperature detector for detecting the temperature (T) of the solution to be measured, and the above-mentioned propagation speed are independently influenced by the concentration of each solute and the temperature of the solution to be measured (n−
1) kinds of specific physical quantities (α ₁ ... Α _n-1 ) and (n-1) kinds of specific physical quantities (α ₁ ) which are independently influenced by the concentration of each solute and the temperature of the solution to be measured. … Α
_n-1 ), a specific physical quantity detector for detecting the concentration of the solution to be measured (T), the specific physical quantity (α ₁ ... α _n-1 ), the ultrasonic wave propagation velocity (V), and the concentration of each solute. A function D ₁ = F ₁ (V, T, α ₁ ... Α _n-1 )... D _n = F _n (V, T, α ₁ ) indicating a relationship with (D ₁ ... D _n )
.. Α _n-1 ), the output (T) of the temperature detector and the output (α ₁ ... Α) of the specific physical quantity detector.
_n-1 ) and the output (V) of the speed calculator, a concentration calculator for calculating the concentration (D ₁ ... D _n ) of each solute based on the function.
And an output device for outputting a calculation result of the density calculation unit.

[Action] In the present invention, for each of various multi-component solutions as the solution to be measured, the specific physical quantity (α ₁ ) such as the temperature (T) and the density (ρ) or the conductivity (σ) of the solution is measured. ... Α _n-1 ), a function D ₁ = F ₁ (V, T, α ₁ ... Α _n ) showing a relationship between the ultrasonic wave propagation velocity (V) and the concentration of each solute (D ₁ ... D _n ). _-1 )… D _n = F _n (V,
T, α ₁ ... Α _n-1 ) are predetermined and stored in the storage unit.
The temperature (T) of the solution to be measured and the specific physical quantity (α ₁ ... Α _n-1 ) are detected by the temperature detector and the specific physical quantity detector. By calculating (V) and substituting the detection result and the calculation result into the above-described function, the concentration (D ₁ ... D _n ) of each solute can be measured reliably and easily.

Embodiment FIG. 1 is a block diagram showing an ultrasonic concentration measuring apparatus according to one embodiment of the present invention, FIG. 2 (A) is a front view showing a sensor used for carrying out the present invention, and FIG. 2B is a sectional view taken along line BB of FIG. 2A, FIG. 2C is a sectional view taken along line CC of FIG. 2A, and FIG. FIG. 4 is a flowchart showing the operation of the ultrasonic concentration measuring apparatus.

The ultrasonic degree measuring apparatus 10 measures the concentration of each solute in a multi-component solution obtained by dissolving a plurality (n) of solutes in a solvent, and includes an arithmetic unit 11 (see FIG. 1), a sensor 12
(See FIG. 2).
It has 13 incidentally.

 The sensor 12 is used by being charged into the solution 1 to be measured.

The sensor 12 includes an ultrasonic transmitter / receiver (vibrator) 14 that also functions as an ultrasonic transmitter and an ultrasonic receiver, and a reflector 15. The ultrasonic wave transmitted from the ultrasonic transducer 14 to the solution 1 to be measured is
The light propagates through the solution to be measured 1 and is reflected by the reflection plate 15 and received by the ultrasonic transducer 14.

The sensor 12 is a temperature detector 16 composed of a thermistor.
And detects the temperature (T) of the solution 1 to be measured.

Further, the sensor 12 is independently affected by the propagation velocity (V) by the concentration of each solute dissolved in the solution 1 to be measured and the temperature (T) of the solution to be measured (n−
1) kinds of specific physical quantities (α ₁ ... Α _n-1 ) and (n-1) kinds of specific physical quantities (α ₁ ) which are independently influenced by the concentration of each solute and the temperature of the solution to be measured. … Α
_n-1 ) is provided. The solution 1 to be measured is obtained by dissolving two solutes (for example, Na
If it is an aqueous solution of OH and NaCl), the sensor 12 includes a conductivity detector 17 for detecting one kind of specific physical quantity, for example, conductivity σ.

The arithmetic unit 11 includes a sing-around unit 18, a temperature measurement unit 19,
A conductivity measuring unit 20, an input / output unit 21, a CPU 22, a ROM 23, and a RAM 24 are provided as an example of the specific physical property measuring unit.

The detection amount of the ultrasonic transducer 14 is the sing-around part 18,
The ultrasonic wave is transferred to the CPU 22 via the input / output unit 21, the propagation speed (V) of the ultrasonic wave is calculated by the CPU 22 as a speed calculation unit, and the calculated speed data (V) is stored in the RAM 24. Sing around method is sent back to tau ₀ seconds after receiving a reflected wave transmits ultrasound burst, the propagation velocity of the repeat conducted ultrasound that performs transmission from the reception of the reflected wave tau after ₀ seconds This is a method for measuring (V). A in FIG. 3 is a transmission wave, and B is a reception wave. The time from the arbitrary transmission time point until the (k + 1) times transmission is performed is represented by t (3rd
Assuming that P = t / K obtained by the calculation is data P, the propagation velocity V is given by the following equation.

V = 2L ₀ / (P−τ ₀ ) where L ₀ is the distance between the ultrasonic transducer 14 and the reflector 15. τ ₀ and L ₀ are initialized by the τ ₀ setting unit 25 and the L ₀ setting unit 26.

The temperature data (T) of the solution 1 to be measured detected by the temperature detector 16 is stored in the RAM 24 via the temperature measuring unit 19, the A / D converter 27, and the input / output unit 21.

The conductivity data (σ) of the solution 1 to be measured detected by the conductivity detector 17 is converted into a conductivity measurement unit 20, an A / D conversion unit 28, and an input / output unit 21.
And stored in the RAM 24.

The ROM 23 of the arithmetic unit 11 constitutes the storage unit of the present invention, and includes the temperature (T) of the solution 1 to be measured, the specific physical quantity (α ₁ .
_n-1 ), ultrasonic wave propagation velocity (V), and concentration of each solute (D ₁ … D
_The following function indicating the relationship with _n ) is stored.

D ₁ = F ₁ (V, T, α ₁ ... Α _n-1 ) (1) D _n = F _n (V, T, α ₁ ... Α _n-1 ) (2) The solution 1 to be measured is, for example, As mentioned above, the two solutes NaOH and Na
Are those obtained by dissolving a Cl, when selecting the conductivity σ as a specific physical property quantity is the concentration D ₁ and the density D ₂ of NaCl of NaOH is as follows.

D ₁ = F ₁ (V, T, σ) (3) D ₂ = F ₂ (V, T, σ) (4) The above function can be represented by a polynomial polynomial.
For an aqueous solution containing two components of NaOH and NaCl as a solute, a polynomial equation including unknown constants C (1) to C (44) is set as follows, for example. Here, up to what order the multi-order polynomial is used is determined by the required accuracy of the concentration measurement.

D ₁ = C (29) * X + C (30) (5) X = (B (1) + C (28) * (B (1) ² + B (2) * B (3)) ^1/2 ) / B (3) B (1) = C (1) + C (2) * T + C (3) * T 2 + C (4) * T 3 + C (5) * T 4 + V * (C (6) + C (7) * T + C (8) * T ² ) + σ * (C (9) + C (10) * T + C (11) * T ² ) B (2) = C (12) + C (13) * T + C (14) * T ² + C (15) * T ³ + C (16) * T ⁴ + V * (C (17) + C (18) * T + C (19) * T ² ) + σ * (C (20) + C (21) * T + C (22) * ^{T 2) B (3) =} C (23) + C (24) * T + C (25) * T 2 + C (26) * T 3 + C (27) * T 4 D 2 = C (31) * Y + C (32) ... (6) Y = (X * (C (33) + C (34) * T + C (35) * T 2) + C (36) + C (37) * T + C (38) * T 2 + V) / (X * ( C (39) + C (40 * T + C (41) * T 2) + C (42) + C (43) * T + C (44) * T 2) constant of the multiple order polynomial C (1) ~C (44) is determined by as follows . That is, in a solution containing two components of NaOH and NaCl as a solute, the concentration of NaOH (D ₁ ) 2.00 to 4.00
%, NaCl concentration (D ₂ ) 10.00-14.00%, temperature (T) 45-
With respect to the combination at 60 ° C., as shown in Table 1, the ultrasonic wave propagation velocity V and the conductivity σ in the solution are measured. The measurement of the temperature (T), speed (V), and conductivity (σ) can be performed using the measuring device 10 of the present invention, as described later. At least 44 combinations of D ₁ , D ₂ , T, V, and σ shown in Table 1 are prepared, and each pair is substituted for the data in the above formulas (5) and (6).
By solving a 44-element simultaneous equation in which the constants C (1) to C (44) are unknown, as shown in Table 2, each constant C (1) to C (44)
C (44) can be determined. This constant C (i) is
The data is stored in the ROM 23 of the arithmetic unit 11 by the ROM writer. The ROM writer calculates each constant C (i) from each of D ₁ , D ₂ , T, V, and σ, and performs a check (D ₁ , D ₂ , T, V, Only when each C (i) is proper (according to σ) is stored in the ROM 23.

Thus, the CPU 22 as the concentration calculator of the present invention calculates the concentration of a solution in which a plurality (n) of solutes (eg, NaOH and NaCl) are dissolved as follows. That is, CPU2
2 is the ultrasonic wave propagation velocity (V) calculated based on the detection amount of the ultrasonic wave transducer 14, the temperature (T) detected by the temperature detector 16, and the data detected by the specific physical quantity detector, for example, conductivity. By substituting each of the rates (σ) into the above formulas (1) and (2), specifically, for example, formulas (5) and (6), the concentration (D ₁ ... D _n ) of each solute, for example, NaOH Concentration D ₁ and NaCl concentration
Calculating a D _2.

The arithmetic unit 11 includes a function setting unit 29.
The function setting unit 29 is for setting the operation of the arithmetic unit 11, and is a mode for measuring and displaying only the propagation speed V of the ultrasonic wave, a mode for measuring and displaying only the temperature T, and a specific physical quantity (α ₁ ... Α _{n−). 1} ) For example, a mode for measuring and displaying only the conductivity σ and a mode for calculating and displaying the densities D ₁ and D ₂ are set. The measurement result and the calculation result obtained by the setting of the function setting unit 29 are displayed on the display unit 13 or taken out from the output unit 30 as an analog output. The display 13 and the output unit 30 constitute an output device of the present invention, and these outputs can be used as a solution to be measured and other control information.

A procedure for measuring the concentration of an aqueous solution containing two components of NaOH and NaCl as a solute by the concentration measuring device 10 will be described below (see FIG. 4). The above-mentioned τ ₀ and L ₀ are set by the τ ₀ setting unit 25 and the L ₀ setting unit 26 of the arithmetic unit 11, and the function setting unit 29 is set to one of the measurement / calculation modes.

In the sonic velocity calculation mode, the sonic velocity processing subroutine operates, and the propagation velocity (V) of the ultrasonic wave in the solution to be measured 1 is calculated and output as described above.

In the temperature measurement mode, the temperature processing subroutine operates, and the temperature (T) of the solution 1 to be measured is measured and output as described above.

In the conductivity measurement mode, the conductivity processing subroutine operates, and the conductivity (σ) of the solution 1 to be measured is measured and output as described above.

In the concentration calculation mode, data obtained in the above subroutines is used, and the NaOH concentration D ₁ and the NaCl concentration D ₂ are calculated and output from the function stored in the ROM 23 as described above. .

For several concentrations D _1, a solution of D ₂ already known for an aqueous solution of two components of the aforementioned NaOH and NaCl as a solute, per various concentrations, D ₁ measured at the concentration measuring apparatus 10, D ₂ Are shown in Table 3 together with the propagation speed (V) of the ultrasonic wave and the conductivity (σ). According to Table 3, it is recognized that the present invention can measure the concentration with high accuracy.

The specific physical quantity used in the practice of the present invention is not limited to the electric conductivity, but may be a density, a PH, a refractive index of light, an attenuation rate of radiation, an operating frequency of ultrasonic waves, and a third
Can be widely adopted. For example, n =
In a multi-component solution in which three types of solutes are dissolved, n
Since −1 = two types of specific physical quantities are used, for example, if the conductivity σ and the density ρ are selected as the specific physical quantities,
The concentrations D ₁ , D ₂ , and D ₃ of each solute are calculated by the following functions.

D ₁ = F ₁ (V, T, σ, ρ) ... (7) D ₂ = F ₂ (V, T, σ, ρ) ... (8) D ₃ = F ₃ (V, T, σ, ρ) (9) That is, according to the present invention, since the concentration of the solution to be measured can be output in real time and high accuracy can be obtained, it is useful for measuring the concentration of various multi-component solutions, and can be used for industrial solutions such as chemicals and foods. Widely applicable to process.

[Effects of the Invention] As described above, according to the present invention, the concentration of each solute in a multi-component solution obtained by dissolving a plurality of solutes in a solvent can be measured reliably and easily.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an ultrasonic concentration measuring apparatus according to one embodiment of the present invention, FIG. 2 (A) is a front view showing a sensor used in the embodiment of the present invention, and FIG. Fig. 2 (A)
FIG. 2 (C) is a cross-sectional view taken along the line BB of FIG.
3 is a waveform diagram showing the state of transmission and reception of ultrasonic waves, and FIG. 4 is a flowchart showing the operation of the ultrasonic concentration measuring device. 10… Ultrasonic concentration measuring device, 11… Computing device, 13 …… Display unit, 14 …… Ultrasonic transducer, 16 …… Temperature detector, 17 …… Conductivity detector, 22 …… CPU ( Speed calculation unit, density calculation unit), 23 ROM (storage unit), 30 output unit.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-73147 (JP, A) JP-A-61-50062 (JP, A) JP-A-62-25254 (JP, A)

Claims (1)

(57) [Claims] An ultrasonic concentration measuring device for measuring each concentration (D ₁ ... D _n ) of a plurality (n) of solutes dissolved in a solvent,
An ultrasonic transmitter for transmitting ultrasonic waves to the solution to be measured, an ultrasonic receiver for receiving ultrasonic waves propagated in the solution to be measured, and a propagation speed (V) based on the propagation time and propagation distance of the ultrasonic waves. ), A temperature detector for detecting the temperature (T) of the solution to be measured, and the above-mentioned propagation speed are independently influenced by the concentration of each solute and the temperature of the solution to be measured (n−
1) kinds of specific physical quantities (α ₁ ... Α _n-1 ) and (n-1) kinds of specific physical quantities (α ₁ ) which are independently influenced by the concentration of each solute and the temperature of the solution to be measured. … Α
_n-1 ), a specific physical quantity detector for detecting the concentration of the solution to be measured (T), the specific physical quantity (α ₁ ... α _n-1 ), the ultrasonic wave propagation velocity (V), and the concentration of each solute. A function D ₁ = F ₁ (V, T, α ₁ ... Α _n-1 )... D _n = F _n (V, T, α ₁ ) indicating a relationship with (D ₁ ... D _n )
.. Α _n-1 ), the output (T) of the temperature detector and the output (α ₁ ... Α) of the specific physical quantity detector.
_n-1 ) and the output (V) of the speed calculator, a concentration calculator for calculating the concentration (D ₁ ... D _n ) of each solute based on the function.
An ultrasonic concentration measurement device comprising: an output device that outputs a calculation result of the concentration calculation unit.