JP2007121133A - Method and apparatus for measuring concentration of insulating matter particles in aqueous solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring the concentration of insulating matter particles such as sand, plastic particles, air bubbles, etc. floating in an aqueous solution. <P>SOLUTION: A pair of electrodes A and B are provided in the aqueous solution W being a measuring target in order to measure the concentration of the volume ratio of the insulating matter particles (d) floating in the aqueous solution W. When the electric resistance value between the electrodes A and B as no insulating matter particles (d) remain afloat in the aqueous solution W and the concentration D of the insulating matter particles (d) is 0 is set to R<SB>0</SB>, the concentration D when the electric resistance value across the electrodes A and B is set to infinity is set to 1 and the electric resistance value across the electrodes A and B in a state that the insulating matter particles (d) floats in the aqueous solution W is set to R, the concentration D in the state that insulating matter particles (d) float in the aqueous solution W is calculated as D=1-R<SB>0</SB>/R. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for measuring the concentration of insulator particles such as sand, plastic, and bubbles floating in an aqueous solution.

As for various conventional densitometers, an optical densitometer using light and an ultrasonic densitometer using ultrasonic waves are generally used. As a concentration meter (turbidimeter) using light, the sample liquid in the cell is irradiated with light, and it is divided into light transmitted by particles (iron) suspended in the liquid and scattered light. Some have detected scattered light, calculated the ratio of scattered light / transmitted light, and displayed it on a display meter as iron concentration (turbidity). (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 9-292329

However, these optical densitometers and ultrasonic densitometers have the disadvantage that output values differ even when the concentration is the same if the particle size of particles floating in water is different. The reason for this is that these optical and ultrasonic densitometers use reflection from particles and thus can only obtain planar information. In order to measure the correct concentration, it is necessary to consider the three-dimensional information of particles floating in water.
In the present invention, when measuring the concentration of insulator particles in an aqueous solution, the concentration of the insulator particles in an aqueous solution that can provide a sensor output with an accurate volume ratio even if the particle size of the insulator particles is different is measured. Methods and apparatus are provided.

In the method for measuring the concentration of insulator particles in an aqueous solution according to the present invention, a pair of electrodes is provided in the aqueous solution to be measured in order to measure the volume ratio concentration of the insulator particles floating in the aqueous solution. In addition, the electric resistance value between the electrodes when the concentration D where the insulator particles are not suspended is 0 is R _0, and the concentration D is 1 when the electric resistance value between the electrodes is set to infinity. , R is an electrical resistance value between the electrodes in a state where the insulator particles are floating in the aqueous solution, and a concentration D in a state where the insulator particles are floating in the aqueous solution is D = 1−R. ₀ / R
It is comprised so that it may obtain | require as.

An apparatus for measuring the concentration of insulator particles in an aqueous solution according to the present invention is provided in an aqueous solution whose concentration is to be measured, and has a volume ratio concentration of the insulator particles in the aqueous solution having a pair of electrodes grounded on one side. The particle concentration detection unit to detect, a sine wave oscillator, the output of the sine wave oscillator is connected to one end, the other electrode of the concentration detection unit is connected to the other end, and between the output and the other end An electric resistance detection amplifier for detecting an electric resistance value between the electrodes having a feedback resistor connected to the output, an absolute value amplifier for converting an output of the interelectrode electric resistance detection amplifier into an absolute value, and an output of the absolute value amplifier A constant adder that adjusts the resistance value at a density D between the electrodes of ₀ as a reference resistance value R ₀ so that the output becomes 0, and is connected to the output of the constant adder, When the resistance value is infinite, A gain adjuster D is adjusted to 1, is connected to the output of the gain adjuster, and an output amplifier for outputting a density D in the concentration measurement in a measurement solution of the concentration detection unit,
After adjusting the constant adder and the gain adjuster to the concentration 0 and the concentration 1 in the aqueous solution to be measured of the concentration detector, respectively, the concentration D in the aqueous solution to be measured is set to D = 1−R ₀ / R
It is comprised so that it may obtain | require as.

  In the present invention, as described above, the concentration by the volume ratio of particles floating between electrodes provided in an aqueous solution is detected as an electric resistance, and can be measured very easily by obtaining the reciprocal of the electric resistance. Is.

  The method and apparatus for measuring the concentration of insulator particles in an aqueous solution according to the present invention uses a pair of electrodes disposed in an aqueous solution and detects the electrical resistance between them. As shown in FIG. 1, the current flowing between the electrodes flows from electrode A to electrode B with a three-dimensional spread like a sphere, so even if the particle size of the insulator particles is different, the sensor output based on the volume ratio Is obtained. In the measurement of the concentration of the insulating particles according to the present invention, it is necessary to measure the concentration in a uniformly distributed state regardless of the particle size of the insulating particles floating in the aqueous solution.

  FIG. 2 is a block circuit diagram showing an embodiment of a method and apparatus for measuring the concentration of the insulator particles d in the aqueous solution W of the present invention. In FIG. 2, reference numeral 1 denotes a particle concentration detection unit installed in the particle suspension aqueous solution W to be measured. Electrodes A and B are provided above and below the insulating frame 1a, and one electrode B is grounded. . The electrodes A and B may be provided on the left and right sides of the insulating frame 1a. Reference numeral 2 denotes a sine wave oscillator having, for example, output characteristics of an oscillation frequency of 8 kHz and an output voltage of about 100 mV. Reference numeral 3 denotes an interelectrode resistance detection amplifier, which is composed of, for example, an operational amplifier and includes a feedback resistor T. An absolute value amplifier 4 converts an AC signal into a negative DC signal.

  Reference numeral 5 denotes a constant adder that adds or subtracts the DC voltage Z. Specifically, in the adjustment before measurement described later, the resistance value of the variable resistor VRZ provided on the input side is increased or decreased to set the output of the constant adder 5 to zero. A gain adjuster 6 is adjusted by increasing or decreasing the feedback signal K. Specifically, in the adjustment before measurement, which will be described later, the resistance value of the variable resistor VRK of the feedback circuit is increased or decreased to adjust the output of the gain adjuster 6 to a required voltage. An output amplifier 7 outputs the concentration D of the insulator particles d as a result of adjustment by the constant adder 5 and the gain adjuster 6.

である。なお、各式中の“Ｃ”は、正弦波発振器２の出力電圧の実効値を示すものである。
粒子濃度検出部１と電極間抵抗検出増幅器３及び帰還抵抗Ｔで構成した回路出力は、
ｖ｛１＋（Ｔ／Ｒ）｝ ……（式２）
となり、絶対増幅器４の極性反転により、
−Ｃ｛１＋（Ｔ／Ｒ）｝ ……（式３）
となる。
定数加算器５及び利得調整器６を通して出力増幅器７からの出力される濃度Ｄは、
Ｄ＝ＫＺ−ＫＣ｛１＋（Ｔ／Ｒ）｝ ……（式４）
である。 Next, the operation of each block circuit will be described quantitatively. The output of the sine wave oscillator 2 in FIG.

It is. Note that “C” in each equation indicates the effective value of the output voltage of the sine wave oscillator 2.
The circuit output composed of the particle concentration detector 1, the interelectrode resistance detection amplifier 3, and the feedback resistor T is
v {1+ (T / R)} (Formula 2)
By the polarity inversion of the absolute amplifier 4,
-C {1+ (T / R)} (Formula 3)
It becomes.
The density D output from the output amplifier 7 through the constant adder 5 and the gain adjuster 6 is
D = KZ−KC {1+ (T / R)} (Formula 4)
It is.

The definition of the concentration D is defined as a volume ratio as an aggregate of the insulating particles d in the aqueous particle suspension, and the electrical resistance between the electrodes AB when the concentration D = 0 is R ₀ , and when D = 1, the electrode The space between A and B is completely filled with insulating particles, and the electric resistance becomes infinite (∞). As shown in FIG. 3, the insulating particles d are aggregated three-dimensionally or planarly, D is an aggregate of the insulating particles d, W is an aqueous solution, and D + W = 1. The electric resistance R changes with the increase / decrease of the aqueous solution W. That is,
R = R ₀ × (1 / W) = R ₀ × {1 / (1-D)}
It becomes. Deformed,
(1-D) R = R ₀
−D = (R ₀ −R) / R
It becomes. Therefore,
D = 1− (R ₀ / R) (Formula 5)
It is expressed by Thus, the value of the density D is 0-1.
Comparing Equation 4 and Equation 5, it can be understood that the adjustment of Z and K makes Equation 4 coincide with Equation 5.

Adjustment of Z When R = R ₀ and D = 0,
0 = KZ−KC {1+ (T / R ₀ )}
Z = C {1+ (T / R ₀ )}.
D = KCT / R ₀ −KCT / R (Formula 6)
The state of R = R ₀ is an aqueous solution without the floating insulating particles d.

Adjustment of K When R = ∞, if D = 1,
1 = KCT / R ₀ Therefore
K = R ₀ / CT, which is substituted into Equation 6
D = 1− (R ₀ / R) (Formula 7)
R = ∞ is a state where there is no aqueous solution between the electrodes.

As a procedure for measuring the concentration, first, the resistance value R ₀ between the electrodes A and B of the aqueous solution W from which the insulator particles d are removed is measured from the aqueous solution W in which the insulator particles d to be concentrated are suspended. The DC voltage Z of the constant adder 5 is adjusted to set the output of the constant adder 5 to 0, and the output of the output amplifier 7 when the density D is 0 is set to 0.
Next, the electrodes A and B of the aqueous solution W are opened, the state without the aqueous solution W, that is, the resistance value R is set to infinity (∞), the feedback signal K of the gain adjuster 6 is adjusted, and the gain adjuster 6 The output of the output amplifier 7 is a voltage that can be easily measured, and this is the output voltage of the output amplifier 7 when the concentration D is 1.
Since the relationship between the electrical resistance value R and the concentration D between the electrodes A and B of the particle concentration detection unit 1 is based on Equation 7, as shown in the interelectrode electrical resistance-concentration diagram shown in FIG. , And is represented as a characteristic diagram by density D = 1−R ₀ / R. However, in the case of FIG. 4, R ₀ = 23Ω.

After adjusting the DC voltages Z and K described above, the state of the resistance value R between the electrodes A and B and the floating insulating particles d are changed so that the aqueous solution W is the aqueous solution W in which the insulating particles d to be measured are floating. The state of the resistance value R ₀ between the electrodes A and B of the nonaqueous solution W is compared, and the measurement result is output to the output of the output amplifier 7. For example, when the output voltage of the output amplifier 7 without the aqueous solution W is adjusted to 1 V and the measured output voltage is 0.32 V, the concentration of the aqueous solution is 32% (volume ratio). Be grasped.

In the above description, the adjustment of Z in the constant adder 5 and the adjustment of K in the gain adjuster 6 are each performed manually, but automatic adjustment may be performed. This is particularly necessary for continuous concentration measurement in a measurement environment where the properties of the aqueous solution change.
In the automatic adjustment of Z, a dedicated detection unit having a concentration D = 0 in which the insulator particles d are not suspended is installed, switched and adjusted at a designated time or time interval, and the value is digitally held. When the property of the aqueous solution W in which the insulator particles d are floating changes, the aqueous solution of the dedicated detection unit is always exchanged so as to correspond to the aqueous solution W to be measured.
In the automatic adjustment of K, the gain adjustment by separating the electrode A or B when the density D = 1 is performed every designated time or time interval, and the value is digitally held. After the automatic adjustment of Z and K, concentration data is detected at the output of the output amplifier 7 by detecting the resistance value R between the electrodes A and B of the aqueous solution W in which the insulator particles d float.

  The electrical conductivity of water varies depending on the type and properties of water. For example, seawater is 10 Ω · cm to 100 Ω · cm, cooling water is around 1 kΩ · cm, tap water is around 10 kΩ · cm, rainwater is 10 kΩ · cm to 100 kΩ · cm, and so on. Etc. need to be considered. In the above description of the circuit, the oscillating frequency of the sine wave oscillator 2 has been described as 8 kHz, but a frequency of about 1 kHz to 60 kHz can be used.

  The method and apparatus for measuring the concentration of insulating particles in an aqueous solution according to the present invention can be applied to the concentration measurement of various aqueous solutions that require concentration measurement based on the volume ratio of the aqueous solution in which the insulating particles float.

It is a schematic diagram explaining the measurement principle of the method and apparatus which measure the density | concentration of the insulator particle | grains in the aqueous solution of this invention. It is a block circuit diagram of one Example of the method and apparatus for measuring the density | concentration of the insulator particle | grains in the aqueous solution of this invention. It is the schematic diagram which made the particle | grain density | concentration in the aggregation state in the method and apparatus which measure the density | concentration of the insulator particle | grains in the aqueous solution of this invention. It is an example of the characteristic view which shows the relationship between the electrical resistance between electrodes in a method and apparatus for measuring the density | concentration of the insulator particle | grains in the aqueous solution of this invention, and a density | concentration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Particle concentration detection part 1a Insulation frame 2 Sine wave oscillator 3 Interelectrode resistance detection amplifier 4 Absolute value amplifier 5 Constant adder 6 Gain regulator 7 Output amplifier

Claims (2)

In order to measure the concentration of the volume ratio of the insulator particles floating in the aqueous solution, a pair of electrodes is provided in the aqueous solution to be measured,
The electrical resistance value between the electrodes in a state where the concentration D where the insulator particles are not suspended in the aqueous solution is 0 is R ₀ ,
The concentration D when the electrical resistance value between the electrodes is set to infinity is 1,
R is an electrical resistance value between the electrodes in a state where the insulator particles are suspended in the aqueous solution,
The concentration D of the state in which the insulator particles in the aqueous solution are floating is D = 1−R ₀ / R
A method of measuring the concentration of insulator particles in an aqueous solution configured to be obtained as: A particle concentration detection unit for detecting the concentration of the volume ratio of the insulating particles in the aqueous solution, which is provided in the aqueous solution to be measured for concentration and has a pair of electrodes grounded on one side;
A sine wave oscillator,
The output between the sine wave oscillator is connected to one end, the other electrode of the concentration detection unit is connected to the other end, and the electric current between the electrodes having a feedback resistor connected between the output and the other end An electrical resistance detection amplifier for detecting a resistance value;
An absolute value amplifier that converts the output of the interelectrode electrical resistance detection amplifier into an absolute value;
A constant adder connected to the output of the absolute value amplifier and capable of adjusting the output to be 0 with a resistance value when the concentration D between the electrodes is 0 as a reference resistance value R ₀ ;
A gain adjuster connected to the output of the constant adder and capable of adjusting the concentration D to be 1 when the resistance value between the electrodes is infinite;
An output amplifier connected to the output of the gain adjuster and outputting a concentration D in the concentration measurement in the aqueous solution to be measured of the concentration detector;
After adjusting the constant adder and the gain adjuster to the concentration 0 and the concentration 1 in the aqueous solution to be measured of the concentration detector, respectively, the concentration D in the aqueous solution to be measured is set to D = 1−R ₀ / R
An apparatus for measuring the concentration of insulator particles in an aqueous solution configured to be obtained as:

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