JP2009250702A - Particle size measuring instrument of particle in liquid and flocculant adding control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately perform the grasping of a flocculation state when adding a flocculant in wastewater treatment or the like. <P>SOLUTION: This particle size measuring instrument of particles in a liquid includes an ultrasonic transmitting-receiving means which includes an ultrasonic transmitter 4 for transmitting an ultrasonic pulse of predetermined frequency into the liquid 20 and an ultrasonic receiver 5 for receiving a reflected pulse produced by reflecting the ultrasonic pulse transmitted from the ultrasonic transmitter 4 by the particles 21 contained in the liquid 20 and constituted so as to relatively move the ultrasonic transmitter 4 at a predetermined moving speed so as to have excessive speed difference with respect to the particles 21 in the liquid 20, a reflected pulse intensity measuring means (control part 10) for measuring the intensity of the reflected pulse received by the ultrasonic receiver and a particle size calculation means (control part 10) for calculating the particle size of the particles from the frequency of the ultrasonic pulse, the moving speed of the ultrasonic transmitter and the reflected pulse intensity measured value measured by the reflected pulse intensity measuring means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for measuring particle size of liquid particles and a flocculant addition control device applicable to the agglomeration and precipitation treatment of waste water, the agglomeration treatment field in water treatment, and the agglomeration treatment in dehydration treatment.

In the agglomeration treatment such as waste water, a method of adding a flocculant to the waste water and aggregating suspended substances contained in the waste water and separating the solid and liquid is adopted. In order to perform wastewater treatment and the like well, it is necessary that suspended substances be well aggregated in the agglomeration treatment, and it is an important task to determine the quality of the agglomerated state in the execution of the agglomeration treatment. .
Conventionally, the quality of the flocculation state in the flocculation process is determined by (1) a method in which the flocculated liquid is artificially collected and implicitly confirmed, or (2) the turbidity of the treated water after flocculation is continuously measured with a turbidimeter or the like Generally, monitoring is performed while measuring. (3) As seen in Patent Document 1, agglomeration reaction solution is irradiated with a laser, and the abundance ratio of particles such as unaggregated SS and aggregating agent (particle concentration) from the lowest scattered light intensity due to light scattering of particles. ) And measuring the aggregation state. Furthermore, (4) a method is known in which the aggregation state is determined by utilizing the feature that particles having a low particle density such as floc absorb a considerable amount of ultrasonic waves. (See Patent Document 2)
JP 2002-195947 A Japanese Patent Publication No. 6-60890

However, among the above methods, since the method (1) is manual, it causes not only individual differences depending on the judgment person's personal opinion in determining the aggregation state, but also when trying to determine the aggregation state continuously. Is unrealistic because it will be assigned to monitoring work for a long time.
The method of (2) is effective because it determines the processing result, but it is a determination after solid-liquid separation after the agglutination reaction, so the time lapse from the event occurrence to the determination Is a problem.
The method (3) has been proposed to solve the problems (1) and (2), but it merely estimates the floc concentration and particle size distribution contained in the measured medium. It cannot be measured directly for each floc. Further, since it is difficult to determine information related to the density of individual flocs, it is impossible to measure the floc strength (correlation with the floc density) which is a determination factor of the aggregation state.
As for the method (4), it is difficult to judge the aggregation of sludge only by the particle density of the sludge particles, and it is necessary to measure the particle size. However, with the method (4), it is not possible to accurately measure the individual particle density. Can not.

  In view of such problems, the present invention aims to make it possible to measure the particle size and density of particles. The basic principle of the present invention is to irradiate particles with ultrasonic waves. The particle size of the particle is measured by the time of the reflected wave generated when the ultrasonic irradiation position is relatively moved at a known speed, and the density of the particle is measured based on the received signal intensity of the ultrasonic wave. By doing.

  That is, among the particle size measuring devices for liquid particles according to the present invention, the first aspect of the present invention is an ultrasonic transmitter that transmits an ultrasonic pulse having a predetermined frequency toward the liquid, and the ultrasonic transmitter. At least one ultrasonic receiver for receiving a reflected pulse in which the transmitted ultrasonic pulse is reflected by particles contained in the liquid is provided, and at least the ultrasonic transmitter has an excessive velocity difference with respect to the particles in the liquid. An ultrasonic transmission / reception unit configured to be relatively movable at a predetermined moving speed, a reflected pulse intensity measurement unit that measures the intensity of the reflected pulse received by the ultrasonic receiver, and A particle diameter calculating means for obtaining a particle diameter of the particle from the vibration frequency of the ultrasonic pulse, the moving speed of the ultrasonic transmitter, and a reflected pulse intensity measurement value measured by the reflected pulse intensity measuring means; The Characterized in that it Bei.

  The particle size measuring instrument for liquid particles according to the second aspect of the present invention is characterized in that, in the first aspect of the present invention, at least the ultrasonic transmitter / receiver moving device that moves the ultrasonic transmitter at the predetermined moving speed is provided. And

  The particle size measuring instrument for liquid particles according to the third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, the movement of the ultrasonic transmitter is a rotational motion.

  In the liquid particle size measuring instrument of the fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the focal point of the ultrasonic pulse transmitted from the ultrasonic transmitter is 1 cm or less in the liquid. It is set so that it may be located in the depth of.

  In the liquid particle size measuring instrument of the fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the ultrasonic transmitter is spaced along the moving direction of the ultrasonic transmitter. It is characterized by being provided with a plurality.

  The particle size measuring apparatus for particles in liquid according to the sixth aspect of the present invention further includes a particle density calculating means for obtaining the particle density of the particles from the measured value of the reflected pulse intensity in any of the first to fifth aspects of the present invention. It is characterized by comprising.

  A flocculant addition control device according to a seventh aspect of the present invention comprises the particle size measuring instrument for liquid particles according to any one of the first to sixth aspects of the present invention, and the flocculant measured by the particle size measuring instrument. A control means for determining the aggregation state of the organic-containing water based on the particle size and particle density of the agglomerated colloidal particles containing the organic substance added with the control, and controlling the addition of the aggregating agent based on the aggregation state. Features.

  The flocculant addition control device according to the eighth aspect of the present invention is the flocculant addition control device according to the seventh aspect of the present invention, wherein the control means adds the amount and / or addition of the flocculant addition device that adds the flocculant to the liquid. It is possible to control the timing.

  According to the present invention, an ultrasonic transmitter that transmits an ultrasonic pulse of a predetermined frequency toward a liquid, and the ultrasonic pulse transmitted from the ultrasonic transmitter is reflected by particles contained in the liquid. At least one ultrasonic receiver for receiving reflected pulses is provided, and at least the ultrasonic transmitter has an excessive speed difference with respect to particles in the liquid and can move relatively at a predetermined moving speed. Ultrasonic transmitting / receiving means, reflected pulse intensity measuring means for measuring the intensity of the reflected pulse received by the ultrasonic receiver, the frequency of the ultrasonic pulse, and the movement of the ultrasonic transmitter Since there is provided a particle size calculating means for obtaining the particle diameter of the particle from the velocity and the reflected pulse intensity measurement value measured by the reflected pulse intensity measuring means, the ultrasonic wave moving the measurement point every moment is provided. The calculated size of the particles, the aggregation state of the particles in the liquid can be determined easily and accurately.

  In order for the ultrasonic measurement point to move relative to the measurement particle, the velocity difference (e.g., relative to the particle) is large enough to maintain the measurement accuracy with respect to the velocity of the particle. Therefore, it is necessary to move it relatively at a speed difference of 10 times or more. In order to meet this requirement, necessary settings are made in consideration of the frequency of the ultrasonic pulse, the moving speed of the particle, the moving speed of the ultrasonic transmitter, the assumed particle size, and the like.

  Further, according to the flocculant addition control device of the present invention, the water-borne particle size measuring device of the present invention is provided, and the organic material-containing water-flocculated colloidal particles to which the flocculant is added are measured by the particle size measuring device. A coagulant addition control means for determining the aggregation state of the organic water based on the particle size and particle density of the liquid and controlling the addition of the coagulant based on the aggregation state. It is possible to accurately maintain the good aggregation state by controlling the addition of the flocculant so as to obtain a good aggregation state.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
The particle size measuring instrument 1 of the present embodiment includes a rotating body 2 that is immersed in a liquid 20 for measurement, and the rotating body 2 is rotatable by being driven by an ultrasonic transmitting / receiving means moving device 3. An ultrasonic transmitter 4 is provided in the rotating body 2 at a position eccentric from the center of rotation. The ultrasonic transmitter 4 transmits an ultrasonic pulse of 1 cm or less from the surface of the rotating body 2. The physical structure and the installation position are set so that the focal point is formed on the outside of the rotating body 2 at a distance of. As a structure for generating an ultrasonic pulse that is focused and focused, a known structure can be used, and the present invention is not limited to a specific structure. In this embodiment, since the rotating body is immersed in the liquid, the focal point is indicated by the distance (depth) from the surface of the rotating body. However, when the rotating body is arranged outside the liquid, the liquid surface It sets so that the said numerical value may be satisfy | filled in the distance (depth) from (liquid tank inner surface etc.). However, since the appropriate value varies depending on the liquid, it must be adjusted for each liquid.
The focal point may be, for example, a circle having a cross-sectional area perpendicular to the traveling direction of the sound wave at the focal point and having a diameter of about 30 μm. The measurement area A is moved.

  If the position of the focal point exceeds 1 cm, the measurement accuracy decreases when a plurality of particles overlap the trajectory of the ultrasonic pulse, which is not preferable.

Further, in the rotating body 2, an ultrasonic receiver 5 that receives a reflected pulse in which an ultrasonic pulse transmitted from the ultrasonic transmitter 4 is reflected by particles in the liquid 20 is disposed. The receiver 5 is located at the rotation center of the rotating body 2 or in the vicinity thereof. The ultrasonic transmitter 4 and the ultrasonic receiver 5 constitute an ultrasonic transmission / reception means of the present invention.
In addition, although resin is mentioned as a raw material of the rotary body 2, as long as it can immerse in water and can maintain intensity | strength even if it rotates, it will not specifically limit.

The ultrasonic transmitter 4 and the ultrasonic receiver 5 are connected to the control unit 10 by signal lines 4a and 5a, and sent from the control unit 10 to the ultrasonic transmitter 4 through the signal line 4a. An ultrasonic pulse having a predetermined frequency is output based on the drive signal. The signal received by the ultrasonic receiver 5 is sent to the control unit 10 through the signal line 5a for data processing. The control unit 10 can be configured as, for example, a CPU and a program that operates the CPU, a ROM that stores the program, a RAM that serves as a work area, a non-volatile flash memory that stores setting data, and the like.
Further, the control unit 10 can send a drive control signal to the ultrasonic transmission / reception means moving device 3 to control the rotation of the ultrasonic transmission / reception means moving device 3, that is, the rotating body 2 at a predetermined speed. In the ultrasonic transmission / reception means moving device 3, rotational position information is acquired by a sensor or the like, and the rotational position information is transmitted to the control unit 10.

The control unit 10 can determine the intensity of the reflected pulse based on the received data of the reflected wave pulse received by the ultrasonic receiver 5. Therefore, the control unit 10 has a function as reflected pulse intensity measuring means.
Further, as will be described later in detail, the control unit 10 is based on the reception data of the reflected pulse, the frequency of the ultrasonic pulse, the moving speed of the ultrasonic transmitter, and the reflected pulse intensity. Thus, the particle size of the particles in the liquid can be obtained. Therefore, the control part 10 has a function as a particle size calculation means.

Next, the operation of the particle size measuring device 1 will be described.
At least the distal end side of the rotating body 2 is immersed in the liquid 20, and the rotating body 2 is moved at a predetermined rotation speed by the ultrasonic transmitting / receiving means moving device 3 based on a drive control signal from the control unit 10.
The transmission signal output from the control unit 10 is transmitted to the ultrasonic transmitter 4 and converted into an ultrasonic signal by the ultrasonic transmitter 4. The ultrasonic waves transmitted from the ultrasonic transmitter 4 reach the outside of the rotating body 2 through the rotating body 2 and focus on the measurement region A.
If a particle 21 in the liquid 20 is present at a measurement point and an ultrasonic pulse output from the ultrasonic transmitter 4 is reflected by the particle 21, a part of the reflected wave is an ultrasonic receiver 5. To reach. In the ultrasonic receiver 5, the received ultrasonic wave is converted into an electric signal and transmitted to the control unit 10. An example of the ultrasonic itinerary and the received waveform at this time is shown in FIG.

  The travel time t shown in FIG. 2 is the propagation time of the sound wave until the ultrasonic wave transmitted from the ultrasonic transmitter 4 in FIG. 1 is reflected by the particle 21 at the measurement point and returns to the ultrasonic receiver 5. It is. In other words, the reflected wave from the particle located at a position other than the measurement region A is always longer or shorter than the travel time of the particle 21 at the measurement point, so that it is received at a constant travel time after the transmission signal is output. By processing only the ultrasonic signal that has been processed, it is possible to process information about the particles 21 only at the measurement points.

  The received sound pressure level is generated because the ultrasonic wave hitting the surface of the particle 21 at the measurement point is generated by the difference in acoustic impedance between the ultrasonic wave propagation medium (air or water here) and the particle 21. The level of the reflected signal is higher when the density difference is larger and the area occupied by the measurement point is larger. Now, when the rotator 2 is immersed in a reaction solution that is undergoing agglomeration treatment, flocs and particles formed in the reaction solution enter the measurement region A. At this time, if the measurement point is moving at a speed sufficiently higher than the movement speed of the floc, the particles can be handled as a stationary object relatively.

  For example, it is assumed that the rotating body 2 rotates at an angular velocity ω (rad / s) and outputs an ultrasonic pulse with a period T (ms). At this time, the movement angle θ (rad) per pulse and the number N of measurement points existing on the circumference of the measurement region are expressed by the following equations.

  Now, when the Nth pulse is fired, the deviation dθ of the starting point is

  That is, the measurement point moves in the direction opposite to the rotation direction for each rotation by nθ (rad). Therefore, when the angular movement speed ν (rad / s) of the measurement point accompanying rotation is obtained, the following equation (5) is obtained.

Consider a case where there is only one measurement point other than the start point on the circumference of the measurement region (N = 1, that is, π <θ <2π).
If the radius of the circumference of the measurement region is r (mm), the moving speed V (mm / s) of the measurement point is given by the following equation.

計測対象となる粒子の移動速度をβ（ｍｍ／ｓ）とする時、回転体の計測点の移動速度Ｖがβよりも十分に大きく（Ｖ＞＞β）、粒子と計測点の相対的な移動速度における粒子の移動速度が無視できる場合を考える。
粒子径を１０μｍ単位で計測するためには、計測１回あたりの計測点の移動距離ｌ（ｍｍ）が１０μｍ以下である必要があるため、下記の式を満足する必要がある。

When the moving speed of the particle to be measured is β (mm / s), the moving speed V of the measuring point of the rotating body is sufficiently larger than β (V >> β), and the relative speed between the particle and the measuring point is Consider the case where the moving speed of particles at the moving speed is negligible.
In order to measure the particle diameter in units of 10 μm, the movement distance l (mm) of the measurement point per measurement needs to be 10 μm or less, and therefore it is necessary to satisfy the following formula.

  Now, if the moving speed β of the particles is 1 mm / s (6 cm / min), the moving speed V (mm / s) of the measurement point is preferably 10 mm / s or more, so the following formula (8) is established.

  If the radius of the rotating body is 10 mm (diameter 20 mm), the following equation (9) is established.

  Substituting r = 10 into Equation 7, the following Equation (10) is obtained.

  From above

  When T = 0.99984084046 ms is selected, the following numerical value is obtained.

Consider a case where N measurement points exist on the measurement circumference.
In this case, the above equation (6) can be rewritten as follows.

  Similarly, when Expression 7 and Expression 8 are rewritten,

  That is, it is possible to set a plurality of arbitrary measurement points on the measurement circumference by giving the ultrasonic pulse emission period T (ms) defined by the relationship N = T ′ / T. However, the travel time of the ultrasonic pulse (the time from when the pulse is emitted until it returns to the measurement point) and the reverberation wave reduction time (the influence of the reverberation wave after emitting the pulse signal on the reception processing is reduced. The time until measurement is required to be taken into account, and when measuring particles of about 10 μm, it is considered that N = 5 is practically appropriate.

  If there is a particle larger than the distance (10 μm) that the measurement region moves at one time and the measurement point crosses the particle, one or more received waves will be obtained, and the detected time (number of times × 10 μm) ) Can be used to estimate the approximate particle size. At this time, the distance from the ultrasonic transmitter 4 to the particle 21 and the ultrasonic receiver 5 is obtained from the rotational position information obtained by the control unit 10, and the time from transmission to reception is also grasped by the control unit 10. Has been.

Consider the case where the measurement point a crosses the particle as shown in FIG. At this time, the reflected wave level changes as the occupied area of the particles occupying the measurement region changes as the measurement point a moves. The number of times the reflected wave level is obtained from when the reflected wave level appears until it disappears depends on the size of the particle. Assuming that the measurement area moves at an interval of 10 μm and the reflected wave is received six times as shown in the figure,
Particle diameter ≒ (moving interval of measurement region) x (number of times the reflected wave level exceeds a certain level) = 10 x 4 = 40 μm
Is calculated.

Further, since the third and fourth received signals are expected to have a particle surface almost in the entire measurement region, it is expected that a received signal level that does not depend on the reflection area can be obtained. Therefore, the reflection intensity (reflection wave level) at this time becomes higher as the density of the particle surface is higher. That is, a signal correlated with the floc intensity (density) can be obtained.
Generally, the higher the density, the higher the acoustic impedance and the higher the reflection intensity.
{Acoustic impedance (Z) = Density (ρ) × Sonic velocity (c)}
A good coagulation floc aggregates SS in water at a high density, so that the reflected wave level becomes high. On the contrary, the reflection level from the flocs with much hydration and little SS becomes low. Thereby, the density of the particles can be calculated in the control unit 10. That is, the control unit 10 functions as a particle density calculation unit.

  In the above measurement method, when it is desired to increase the resolution (see smaller particles), the moving speed V of the measurement point given by the above equation 6 may be decreased. That is, by increasing the radius of the rotating body and reducing the “deviation” angle of the measurement point for each rotation given from the angular velocity ω of the rotating body and the ultrasonic wave transmission period T, it is possible to take fine sampling points. However, in order to increase the size of the rotator and the angular velocity of the rotator and to rotate it faster, or to shorten the transmission interval of the ultrasonic wave according to the rotation speed, the rotation speed and rotation for expanding the dimensions It is subject to physical constraints due to problems of accuracy, problems of the drive source of the rotating body, problems of ultrasonic wave propagation speed, and the like.

  As a countermeasure against the physical constraints as described above, there is means for increasing the number of transmitters as described in the explanation paragraphs 0045 to 0050 of the application example. In this case, as shown in FIG. 4, in addition to a method of preparing a receiver for each transmitter in pairs, it is provided at the center of the rotating body and receives signals from all the transmitters by one receiver. A method is also possible. An example using a plurality of transmitters will now be described with reference to FIG.

FIG. 4A is a view as seen from the tip of the rotating body 2. The ultrasonic transmitters 40 to 43 and the ultrasonic receivers 50 to 53 are arranged at intervals of 90 degrees along the rotation direction of the rotating body 2, and the ultrasonic pulses transmitted from the respective transmitters are particles in the liquid. The reflected pulse reflected is received by each receiver. FIG. 4B shows a measurement point a0 due to transmission of an ultrasonic pulse from the ultrasonic transmitter 40, a measurement point a1 due to transmission of an ultrasonic pulse from the ultrasonic transmitter 41, and an ultrasonic pulse from the ultrasonic transmitter 42. The measurement point a2 by the transmission of the ultrasonic wave, the measurement point a3 by the transmission of the ultrasonic pulse of the ultrasonic transmitter 43, and the reflected wave level of the reception wave obtained by each measurement point are shown. The received waves are received by the ultrasonic receivers 50 to 53, respectively, and can be processed by the control unit 10, and the received waves received by the ultrasonic receivers 50 to 53 are combined to generate the reflected pulses. The particle size can be calculated.
By the method as described above, the ultrasonic element can be rotated together with the rotating rotating body, and the size of the object can be measured by moving the measurement region accompanying the rotation.

An example in which the particle size measuring device is applied to solid-liquid separation processing of waste water will be described with reference to FIG.
In the solid-liquid separation process of this example, the adjustment pond 100 that stores the wastewater, and the aggregation reaction tank 110 that introduces the wastewater from the adjustment pond 100 and adds an appropriate flocculant by the flocculant addition device 111 to grow the floc. And a filtering device 120 that performs solid-liquid separation by introducing wastewater in which flocs are grown from the agglomeration reaction tank 110. In addition, as an apparatus which performs solid-liquid separation, it is not limited to a filtration apparatus. Further, the agglomeration reaction tank 110 is provided with an agitation and mixing means 112 for agitating the drainage to which the aggregating agent is added to increase the growth of flocs.

  As an installation position of the particle size measuring instrument 1 according to the present invention, the agglomeration reaction tank 110 outlet E1 is desirable, but it may be the inlet E2 of the filtration device 120. In this example, the flocculant addition device 111 can be controlled by the control unit 10 provided in the particle size measuring instrument 1, and the flocculant addition timing by the flocculant addition device 111 can be controlled. . Further, the flocculant addition apparatus 111 may employ a configuration in which the addition amount can be adjusted so that the control amount of the additive can be controlled by the control unit 10.

The waste water whose pH and the like are adjusted by the adjustment basin 100 is introduced into the agglomeration reaction tank 110, the aggregating agent is added by the aggregating agent adding device 11, and the agitation and mixing means 112 is further agitated and mixed. The suspension in the wastewater to which the flocculant is added grows into flocs by charge neutralization and crosslinking. At this time, the floc moves at a predetermined flow rate by the stirring and mixing.
The wastewater that has been subjected to the agglomeration process is subjected to solid-liquid separation by separating the flocs sufficiently agglomerated in the filtration device 120 by filtration, and further supplied to a downstream process or the like.

  As for the waste water, the particle size and particle density of flocs are calculated by using the ultrasonic wave as described above at the outlet E1 of the agglomeration reaction tank 110 and the inlet E2 of the filtration device 120 as described above. . A pattern example of the particle size distribution and the intensity distribution by the measurement is shown in FIG.

  When the flocculant is insufficient with respect to the wastewater that has flowed in, the growth of flocs is insufficient, and a large amount of fine fine particles that are not taken into the flocs remain, so the smaller one (for example, 10 μm) The flow rate distribution characteristic has peaks in the following (FIG. 6A). In addition, the reflected intensity of the ultrasonic wave returned from the small particle at this time is almost similar to the reflected wave of the solid substance itself, but the reflected wave with a low intensity is generated because the volume of the ultrasonic reflected pair is small. Come back (Fig. 6 (A)).

  Assuming that the flocculant is properly injected, the suspension is taken up into the floc and grows large, so that the flow rate distribution has a peak at the larger particle size (for example, 100 to 500) (FIG. 6B). ). On the other hand, fine particles are reduced because they are taken into the floc. In addition, since flocs that have grown greatly in ultrasonic reflection intensity have an appropriate solid density, strong reflection intensity can be obtained on the larger particle size side (FIG. 6B).

  On the other hand, if the flocculant is injected excessively, the floc grows larger, while the amount of hydroxide in the floc increases and the solid density decreases, so the floc itself becomes fragile and breaks. Although fine hydroxide flocs are generated and the flow rate distribution has a larger peak (for example, 500 μm or more), it has a broad shape as a whole (FIG. 6C). In addition, the reflection intensity from the particles does not increase so much that the volume of the reflection object increases as the solid density decreases and the particle size increases (FIG. 6C).

On the other hand, depending on the properties of the waste water and the solid-liquid separation means in the subsequent stage, there are cases where the optimum aggregation state depends on the particle diameter and on the reflected wave intensity. For example, in the case of a filter that easily causes clogging due to excessive injection of a flocculant, such as a sand filtration device, the dosage of the flocculant may be adjusted in the direction of optimizing the particle size. In the case of a screw press dehydrator or the like, it is necessary to inject the flocculant to some extent, and in this case, it is more suitable to judge by the reflection intensity rather than the particle size distribution.
As described above, it is possible to evaluate both the particle size distribution and the reflection intensity with respect to changes in the aggregation state caused by the aggregating agent, so that the amount of the aggregating agent can be kept appropriate to the properties of the waste water. It becomes.

The addition adjustment of the flocculant is performed by displaying the measurement result by the particle size measuring instrument 1 on a display device or the like, and the operator can adjust the addition of the flocculant according to the display content, but the measurement result is fed back. Thus, the addition of the flocculant can be controlled. An example of this will be described below.
For example, as shown in Table 1, the determination criterion of the aggregation state is set in advance in a nonvolatile memory of the control unit 10, and based on the measurement result measured by the particle size measuring device 1, The aggregation state can be determined. The control unit 10 can control the addition of the flocculant by feedback control of the flocculant addition device 111 based on the determination result. Therefore, the control unit 10 functions as a flocculant addition control unit. With this control, it is possible to appropriately perform wastewater treatment and the like while always maintaining a good aggregation state in the aggregation reaction tank 110.

  In the description of the above embodiment, the particle size measuring device provided with one ultrasonic transmitter and one ultrasonic receiver has been described as an example, but the present invention is not limited to this, A device provided with a plurality of them exhibits the same function.

It is the schematic which shows the particle size measuring apparatus of one Embodiment of this invention. Similarly, it is a figure which shows the itinerary of the ultrasonic wave in a particle size measuring instrument. Similarly, it is a figure which shows the locus | trajectory of the measurement point in a measurement area | region, and the reflected wave level by measurement. It is a figure which shows the example of arrangement | positioning of the ultrasonic transmission / reception means in other embodiment of this invention, the locus | trajectory of the measurement point in a measurement area | region, and the reflected wave level by measurement. It is a figure which shows the example of application of the coagulant | flocculant addition control apparatus of this invention. Similarly, it is a figure which shows the pattern of an ultrasonic measurement result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Particle size measuring instrument 2 Rotating body 3 Ultrasonic transmission / reception means moving device 4 Ultrasonic transmitter 5 Ultrasonic receiver

Claims (8)

An ultrasonic transmitter that transmits an ultrasonic pulse of a predetermined frequency toward the liquid, and a reflected pulse in which the ultrasonic pulse transmitted from the ultrasonic transmitter is reflected by particles contained in the liquid. Ultrasound including at least one ultrasonic receiver, and at least the ultrasonic transmitter having an excessive speed difference with respect to particles in the liquid and capable of moving relatively at a predetermined moving speed Transmitting and receiving means;
Reflected pulse intensity measuring means for measuring the intensity of the reflected pulse received by the ultrasonic receiver;
Particle size calculating means for determining the particle diameter of the particles from the vibration frequency of the ultrasonic pulse, the moving speed of the ultrasonic transmitter, and the reflected pulse intensity measurement value measured by the reflected pulse intensity measuring means; A device for measuring the particle size of particles in liquid.   2. The particle size measuring apparatus for particles in liquid according to claim 1, further comprising an ultrasonic transmission / reception means moving device for moving at least the ultrasonic transmitter at the predetermined moving speed.   The apparatus for measuring a particle size of liquid particles according to claim 1 or 2, wherein the movement of the ultrasonic transmitter is a rotational motion.   The ultrasonic particles transmitted from the ultrasonic transmitter are set so that the focal point of the ultrasonic pulse is located at a depth of 1 cm or less in the liquid. Particle size measuring instrument.   The particle size measurement of particles in liquid according to any one of claims 1 to 4, wherein a plurality of the ultrasonic transmitters are provided at intervals along the moving direction of the ultrasonic transmitters. machine.   The particle size measuring device for particles in liquid according to any one of claims 1 to 5, further comprising a particle density calculating means for obtaining a particle density of the particles from the measured value of the reflected pulse intensity.   The particle size measurement apparatus of the particle | grains in a liquid of any one of Claims 1-6, The particle size of the aggregation colloidal particle of the organic substance containing water which added the flocculent measured by this particle size measurement device, and A flocculant addition control device comprising: flocculant addition control means for determining the aggregation state of the organic water based on particle density and controlling the addition of the flocculant based on the aggregation state.   8. The flocculant addition control device according to claim 7, wherein the control means can control the addition amount and / or addition timing of the flocculant addition device for adding the flocculant to the liquid.

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