JPH10104150A - Detector for particle in liquid - Google Patents

Abstract

(57) [Summary] [Problem] It is impossible to selectively count only particles in a sample liquid containing air bubbles because particles and air bubbles cannot be distinguished. SOLUTION: First and second light scattering type particle detectors 2 and 4 for outputting a signal corresponding to a particle diameter of particles or bubbles existing in a sample liquid passing through a flow path 10, first and second light scattering type particle detectors, A cooler 3 installed in a flow path 10 between the second light scattering type particle detectors 2 and 4 to cool a passing sample liquid to a predetermined temperature.
And a signal processing unit 5 for comparing and calculating the output signals of the first and second light scattering particle detectors 2 and 4 to calculate the particle diameter and the number of particles such as particles and bubbles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submerged particle detector for separating particles and bubbles in a liquid containing particles and bubbles and detecting the particle diameter and the number of particles and bubbles.

[0002]

2. Description of the Related Art An in-liquid particle detection device can measure minute particles contained in a sample liquid in real time, and can obtain measurement results with little individual difference. In addition, it is possible to measure a liquid having extremely high cleanliness, such as one particle per liter. And it is used for particle detection in many fields, for example, in the fields of electronics industry, precision machinery, medicine, food and the like.

[0003] These liquids may contain air bubbles, and there is a strong demand to measure and manage particles in the liquids containing air bubbles. Examples of the liquid containing bubbles include a stirred liquid, a liquid containing a surfactant, and a liquid that easily foams such as beer and carbonated beverages.

[0004]

However, in the conventional apparatus for detecting particles in liquid, since particles and bubbles cannot be distinguished, it is difficult to selectively count only particles in the sample liquid containing bubbles. It was possible. Therefore, it was not possible to control the particle concentration of the sample liquid in which particles and bubbles were mixed.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a method for distinguishing particles and bubbles in a sample liquid and counting them in a liquid. It is intended to provide a particle detection device.

[0006]

According to a first aspect of the present invention, there is provided a first and a second means for outputting a signal corresponding to a particle diameter of particles or bubbles existing in a sample liquid passing through a flow path. A second particle detecting means, a liquid temperature changing means provided in a flow path between the first and second particle detecting means for cooling or heating a sample liquid passing therethrough to a predetermined temperature, and the first and second liquid detecting means. And a signal processing means for calculating the particle size and the number of particles such as particles and bubbles by comparing and calculating the output signal of the particle detecting means.

According to a second aspect of the present invention, in the apparatus for detecting particles in liquid according to the first aspect, the signal processing means converts an output signal of the first particle detection means and an output signal of the second particle detection means. Comparing, when the peak value of the output signal of the first particle detecting means is substantially equal to the peak value of the output signal of the second particle detecting means, a peak value comparing circuit for outputting a particle corresponding signal; It is provided with a particle counting display unit for counting and displaying the particle corresponding signal of the comparison circuit.

According to a third aspect of the present invention, in the liquid particle detecting device according to the first aspect, the signal processing means converts an output signal of the first particle detecting means and an output signal of the second particle detecting means. Comparing, when the peak value of the output signal of the first particle detecting means is substantially equal to the peak value of the output signal of the second particle detecting means, outputting a particle corresponding signal; A crest value comparison circuit for outputting a bubble correspondence signal when there is a difference between the crest value of the output signal and the crest value of the output signal of the second particle detection means; and counting the particle correspondence signal of the crest value comparison circuit. The apparatus further comprises a particle count display section for displaying, and a bubble count display section for counting and displaying the bubble corresponding signal of the peak value comparison circuit.

According to a fourth aspect of the present invention, in the liquid particle detecting apparatus according to the second or third aspect, the sample liquid is provided between the first particle detecting means and the peak value comparing circuit. A delay circuit may be provided for delaying the output signal of the first particle detection means by the time required for passing between the particle detection means.

According to a fifth aspect of the present invention, in the apparatus for detecting particles in liquid according to the first, second, third or fourth aspect, the first and second particle detecting means are light scattering type particle detectors. it can.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a configuration diagram of a submerged particle detection device according to claim 3, FIG. 2 is a configuration diagram of a submerged particle detection device of claim 4, FIG. 3 is a characteristic diagram showing solubility of air in water, FIG. Is a characteristic diagram showing the relationship between the particle size of the particles contained in the liquid and the light scattering intensity, and FIG. 5 is a configuration diagram of an example of the particle detection means.

As shown in FIG. 1, an apparatus 1 for detecting particles in liquid according to claim 3 comprises a first light scattering type particle detector 2, a cooler 3 for cooling a passing sample liquid to a predetermined temperature, and a second light. The apparatus includes a scattering type particle detector 4, a signal processing unit 5, and a flow control unit 6. Here, the first and second light scattering type particle detectors 2, 4
Are the same, detect scattered light emitted from particles, bubbles and the like in the sample liquid when the sample liquid is irradiated with light, and output an electric pulse signal having a wave height corresponding to the intensity of the scattered light. Note that, as is well known, the greater the particle size of the particles and bubbles, the higher the intensity of the scattered light emitted by the particles and bubbles.

The signal processing unit 5 compares the peak value A of the electric pulse output from the first light scattering type particle detector 2 with the peak value B of the electric pulse output from the second light scattering type particle detector 4. It comprises a pulse peak value comparison circuit 7, a particle count display section 8 for counting and displaying the number of particles, and a bubble count display section 9 for counting and displaying the number of bubbles.

The pulse peak value comparing circuit 7 compares the peak value A of the output pulse of the first light scattering type particle detector 2 with the peak value B of the output pulse of the second light scattering type particle detector 4, and compares them. When the peak values A and B are substantially equal (A ≒ B), a pulse corresponding to the particle is output, and the peak value A of the output pulse of the first light scattering type particle detector 2 is equal to that of the second light scattering type particle detector 4. If the peak value of the output pulse is larger than B (A> B), a bubble-corresponding pulse is output.

The flow rate control means 5 controls whether the sample liquid is the first liquid.
In order to connect the light scattering type particle detector 2, the cooler 2, and the second light scattering type particle detector 4, and to control the flow path 10 constituting the submerged particle detection device 1 to flow at a desired constant speed. Is provided. In addition, when the particle detection in the plant is performed by inserting the submerged particle detection device into a part of the flow path of the plant and the pressure of the sample liquid in the plant flow path is constant, the flow control means 5 is necessarily provided. No need.

Particle counting display 8 and bubble counting display 9
Counts the particle-corresponding pulse and the bubble-corresponding pulse output from the pulse crest value comparison circuit 7, and displays the counting result as the number of particles and the number of bubbles.

The apparatus for detecting particles in liquid 1 configured as described above
The operation of will be described. When a sample liquid containing particles or air bubbles is introduced into the particle-in-liquid detection device 1, when the sample liquid passes through the first light-scattering particle detector 2, the first light-scattering particle detector 2 And outputs an electric pulse corresponding to the particle size. The cooler 3 cools the sample liquid to a predetermined temperature. Then, the sample liquid cooled by the cooler 3 is
When passing through the light scattering type particle detector 4, the second light scattering type particle detector 4 outputs an electric pulse corresponding to the particle diameter of particles or bubbles contained in the sample liquid.

When the particles pass through the submerged particle detection device 1, the particles do not change in size even if they are cooled.
The peak values A and B of the electric pulses output by the first and second light scattering type particle detectors 2 and 4 do not change. Note that the first and second light scattering particle detectors 2 and 4 are kept for a time sufficiently longer than the time when the particles or bubbles pass from the first light scattering particle detector 2 to the second light scattering particle detector 4. If the particles or bubbles can be detected and the concentration or ratio of the particles or bubbles is stable over time, that is, if the concentration distribution of the particles or bubbles and the ratio of the particles or bubbles are substantially uniform, the first and second light beams are detected. There is no problem even if the timings of the electric pulses output by the scattering particle detectors 2 and 4 are shifted.

The electric pulse output from the first light scattering type particle detector 2 and the electric pulse output from the second light scattering type particle detector 4 are input to a pulse peak value comparison circuit 7. When the peak values A and B of these electric pulses are substantially the same (A ≒ B), the pulse peak value circuit 7 outputs a particle-corresponding pulse. Therefore, when the sample liquid has passed through the in-liquid particle detection device 1, the number of particles contained in the sample liquid is displayed on the particle count display unit 8.

On the other hand, when air bubbles pass through the liquid particle detection device 1, since the air bubbles are cooled and the particle diameter is reduced, the peak value A of the electric pulse output from the first light scattering type particle detector 2 is obtained. Is larger than the peak value B of the electric pulse output from the second light scattering type particle detector 4.

One of the reasons is that the solubility of a gas in a liquid (the amount of gas dissolved in the liquid) decreases as the temperature decreases. When a gas is present in a sample liquid, a part of the gas is dissolved in the liquid, and a part that cannot be dissolved in the liquid is a bubble, and the particle size of the bubble at this time depends on the solubility. FIG. 2 shows the case where air bubbles are present in water.

The second reason is that, as shown in FIG. 3, when particles or bubbles are irradiated with light, the light scattering intensity generated by the particles or bubbles depends on the particle size of the particles or bubbles. This is because the larger the value, the higher the light scattering intensity. In particular, when the particle size is small, the light scattering intensity is proportional to the sixth power of the particle size.

For example, when the bubble is the first light scattering type particle detector 2
Assuming that the initial temperature of the sample liquid is 40 ° C. when the sample liquid is cooled to 20 ° C. by the cooler 3, the solubility at 40 ° C. is 0.014,
Is 0.019. This means that the particle size of the bubbles at 40 ° C. is 1.1 times the particle size at 20 ° C. Further, assuming that the bubble diameter is about 0.2 to 0.3 μm, the light scattering intensity is 6
Since the light scattering intensity at 20 ° C. and the light scattering intensity at 40 ° C. are compared with each other, the latter is 1.8 times as large as the former.

In the case of bubbles, the peak value A of the electric pulse output from the first light scattering type particle detector 2 is larger than the peak value A of the electric pulse output from the second light scattering type particle detector 4. It is larger than the peak value B. In this case, the pulse peak value circuit 7
Outputs a bubble-corresponding pulse, so that the number of bubbles is displayed on the bubble count display section 9 when the bubbles pass through the liquid particle detection device 1.

As shown in FIG. 2, the apparatus for detecting particles in liquid 11 according to claim 4 is different from the apparatus for detecting particles in liquid 1 according to claim 3 in that the first light scattering type particle detector 2 and the pulse peak value comparing circuit 7 are used. A delay circuit for delaying the output signal of the first light scattering type particle detector 2 by the time during which the sample liquid passes between the first light scattering type particle detector 2 and the second light scattering type particle detector 4 12
Is provided.

When the concentration or ratio of the particles or bubbles of the sample liquid is low and the concentration distribution of the particles or bubbles and the ratio of the particles or bubbles are not uniform, the electric pulse output from the first light scattering type particle detector 2 is used. And the timing of the electric pulse output by the second light scattering type particle detector 4 becomes a problem.
Therefore, the electric pulse output from the first light scattering type particle detector 2 and the electric pulse output from the first light scattering type particle detector 2 are delayed by delaying the electric pulse output from the first light scattering type particle detector 2 by the delay circuit 12 described above. The electric pulse output from the heater 4 is simultaneously input to the pulse peak value comparison circuit 7.

The pulse peak value comparing circuit 7 includes a delay circuit 12
Is compared with the peak value B of the electric pulse output from the second light scattering type particle detector 4,
When the peak value A of the electric pulse output from the delay circuit 12 is substantially equal to the peak value B of the electric pulse output from the second light scattering type particle detector 4 (A ≒ B), a pulse corresponding to the particle is output, and the delay circuit is output. When the peak value A of the electric pulse output from 12 is greater than the peak value B of the electric pulse output from the second light scattering type particle detector 4 (A> B), a bubble-corresponding pulse is output.

The liquid particle detecting device 1 configured as described above
1 will be described. When a sample liquid containing particles or air bubbles is introduced into the particle-in-liquid detection device 1, when the sample liquid passes through the first light-scattering particle detector 2, the first light-scattering particle detector 2 And outputs an electric pulse corresponding to the particle size. The cooler 3 cools the sample liquid to a predetermined temperature. When the sample liquid cooled by the cooler 3 passes through the second light scattering type particle detector 4, the second light scattering type particle detector 4 corresponds to the particle diameter of particles or bubbles contained in the sample liquid. Output the generated electric pulse.

When the particles pass through the submerged particle detector 11, since the particles do not change in size even if they are cooled, the first and second light scattering type particle detectors 2 and 4 output the respective particles. The peak values A and B of the generated electric pulse do not change. However, since the timings of these electric pulses are shifted, the electric pulse output from the first light scattering type particle detector 2 is delayed by the above-described delay circuit 12, so that the first light scattering type particle detector 2 outputs And the electric pulse output from the second light scattering type particle detector 4 are input to the pulse peak value comparison circuit 7 at the same time.

When the peak values A and B of these electric pulses are substantially the same (A ≒ B), the pulse peak value circuit 7 outputs a particle-corresponding pulse. Therefore, when the sample liquid has passed through the in-liquid particle detection device 11, the number of particles contained in the sample liquid is displayed on the particle count display section 8.

When the air bubbles pass through the submerged particle detector 11, the peak value A of the electric pulse output from the first light scattering type particle detector 2 is higher than that of the second light scattering type particle detector. 4
Is larger than the peak value B of the output electric pulse. Then
Since the pulse crest value circuit 7 outputs a bubble-corresponding pulse, the number of bubbles is displayed on the bubble count display unit 9.

As described above, the scattered light emitted from the particles in the sample liquid does not change even when the temperature of the sample liquid decreases, whereas the scattered light emitted from the bubbles in the sample liquid decreases when the temperature of the sample liquid decreases. If the number of pulse corresponding to particles and the number of pulses corresponding to bubbles in the pulse peak value comparison circuit 7 are counted, particles and bubbles can be separately counted.

In the above-described embodiment, the temperature of the sample liquid is changed from a high temperature to a low temperature by using the cooler 2. Since it may be provided, a heater may be used instead of the cooler 2. However, in this case, when the peak value A of the electric pulse output from the first light scattering type particle detector 2 is smaller than the peak value B of the electric pulse output from the second light scattering type particle detector 4, the pulse The peak value comparison circuit 7 must output a bubble-corresponding pulse.

In the above embodiment, the light scattering particle detectors 2, 4 are used as the first and second particle detecting means.
However, since it is only necessary to use a particle detector that outputs an electrical signal corresponding to the size of the particles, another type of particle detector may be used.

For example, a so-called light-blocking type in which light is applied to a channel portion, and the particle size of the particles is measured by measuring the intensity of irradiation light reduced by the passage of particles through the channel portion. As shown in FIG. 5, the electrolyte solution 21 is passed through a pinhole 23 formed in a partition wall 22 made of an insulator. May be used.

[0036]

As described above, according to the first aspect of the present invention, the provision of the liquid temperature changing means makes it possible to distinguish between bubbles and bubbles of the sample liquid in which the bubbles are mixed, and to count each of them. it can.

According to the second aspect of the present invention, it is possible to count only the particles of the sample liquid in which bubbles and particles are mixed, and display this value.

According to the third aspect of the present invention, particles and bubbles of the sample liquid in which bubbles and particles are mixed can be separately counted and these values can be displayed.

According to the fourth aspect of the present invention, even if the concentration or ratio of the particles or bubbles of the sample liquid is low, and the concentration distribution of the particles or bubbles or the ratio of the particles or bubbles is not uniform, the bubbles and the particles may not be uniform. Particles and bubbles of the sample liquid in which are mixed are separately counted, and these values can be displayed.

According to the fifth aspect of the present invention, particles or bubbles in a sample liquid containing bubbles and particles can be detected with high accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for detecting particles in liquid according to claim 3;

FIG. 2 is a configuration diagram of a liquid particle detection device according to claim 4;

FIG. 3 is a characteristic diagram showing solubility of air in water.

FIG. 4 is a characteristic diagram showing a relationship between a particle size of particles contained in a liquid and a light scattering intensity.

FIG. 5 is a configuration diagram of an example of a particle detection unit.

[Explanation of symbols]

Reference numerals 1, 11: liquid particle detecting device, 2: first light scattering type particle detector (first particle detecting means), 3: cooler (liquid temperature changing means), 4: second light scattering type particle detector (Second particle detecting means), 5: signal processing unit (signal processing means), 6: flow rate control unit, 7: pulse peak value comparison circuit (peak value comparison circuit), 8: particle count display unit, 9: bubble Count display, 10
... a flow path, 12 ... a delay circuit.

Claims (5)

[Claims] 1. First and second particle detecting means for outputting a signal corresponding to the particle diameter of particles or bubbles existing in a sample liquid passing through a flow path, and first and second particle detecting means Liquid temperature changing means for cooling or heating a sample liquid passing therethrough provided in a flow path between the first and second particle detection means, and performing comparison operation processing on the output signals of the first and second particle detection means to obtain particles, bubbles, etc. 1. A submerged particle detection device comprising signal processing means for calculating the particle diameter and the number of particles. 2. The signal processing unit compares an output signal of the first particle detection unit with an output signal of the second particle detection unit, and determines a peak value of the output signal of the first particle detection unit. When the peak value of the output signal of the second particle detecting means is substantially equal to the peak value comparing circuit that outputs a particle corresponding signal, and a particle count display unit that counts and displays the particle corresponding signal of the peak value comparing circuit. The apparatus for detecting particles in liquid according to claim 1, further comprising: 3. The signal processing unit compares the output signal of the first particle detection unit with the output signal of the second particle detection unit, and determines that the peak value of the output signal of the first particle detection unit is high. A particle-corresponding signal is output when the peak value of the output signal of the second particle detecting means is substantially equal to the peak value of the output signal of the first particle detecting means and the output signal of the second particle detecting means. A crest value comparison circuit that outputs a bubble correspondence signal when there is a difference in crest values, a particle count display unit that counts and displays the particle correspondence signal of the crest value comparison circuit, and a bubble correspondence signal of the crest value comparison circuit 2. The liquid particle detection device according to claim 1, further comprising a bubble counting display unit that counts and displays the number of bubbles. 4. An output of said first particle detecting means for a time period during which a sample liquid passes between said first and second particle detecting means between said first particle detecting means and said peak value comparing circuit. 4. A delay circuit for delaying a signal.
The device for detecting particles in liquid according to the above. 5. The first and second particle detecting means,
The liquid particle detection device according to claim 1, which is a light scattering type particle detector.