JP4602119B2 - Streaming potential measuring device and aggregation state detection system - Google Patents

Description

  The present invention relates to a streaming potential measuring device that measures the streaming potential of water to be treated, and an aggregation state detection system that detects the aggregation state of colloidal particles in the water to be treated.

  Conventionally, in order to purify the water to be treated such as raw water sent from a river or the like, a flocculant is added to the water to be treated, and the colloidal particles such as suspended substances in the water to be treated are aggregated and removed by precipitation. The method is used. Specifically explaining such a coagulation-precipitation treatment, first, an aluminum-based or iron-based inorganic coagulant or polymer coagulant is injected into the water to be treated, and the mixture is rapidly stirred in a relatively short time. A micro flock is generated as a nucleus. Thereafter, the water to be treated is gently agitated, and the micro flocs are collided and combined to further enlarge the micro flocs to promote sedimentation. A clear supernatant water can be obtained by carrying out precipitation removal of such colloidal particles.

  In the coagulation sedimentation treatment, coagulation conditions such as the addition amount of the coagulant, the stirring speed, the stirring time, the temperature of the water to be treated, the pH of the water to be treated must be appropriate. Here, if the aggregation state of the colloidal particles in the water to be treated after adding the flocculant to the water to be treated can be detected quickly and accurately, the addition amount of the flocculant can be an appropriate amount, and Clear supernatant water can be obtained.

  As a method for detecting the aggregation state of the colloidal particles in the water to be treated, there is a method for optically directly measuring the particle diameter of the colloidal particles (see Patent Document 1) or a method for measuring the zeta potential of the water to be treated. Are known. The latter method for measuring the zeta potential of water to be treated will be described in detail below.

The zeta potential is the potential with respect to the solution bulk of the solution slip surface on the surface of the colloid particles. When the aggregation of colloid particles proceeds to an unstable state, the potential of the solution slip surface on the surface of the colloid particles becomes the potential of the solution bulk. Therefore, the zeta potential is almost zero.
That is, colloidal particles in the water to be treated have a high electrostatic repulsion force when the absolute value of the zeta potential is large, so that the dispersibility is increased. On the other hand, when the zeta potential approaches 0, the electrostatic repulsion force is weak. Therefore, it becomes easy to aggregate. Thus, the aggregation state of colloidal particles can be detected based on the magnitude of the zeta potential.

  As a method for measuring the zeta potential of colloidal particles in the water to be treated, for example, electrophoresis light scattering in which electrophoretic light is obtained by irradiating the electrophoretic particles with laser light and measuring the migration speed in the scattered light. The law is known. However, this method cannot measure the zeta potential of colloidal particles in the water to be treated in real time, and this method is applied when the colloidal particles are too large or the aggregated state is unstable. I can't.

As other methods for measuring the zeta potential of colloidal particles, the electroosmosis method, the streaming potential method or the sedimentation potential method is known. Of these, the streaming potential method is mainly used in the coagulation sedimentation treatment. . The streaming potential method is a method of detecting the zeta potential by measuring the flowing current of the water to be treated by utilizing the proportional relationship between the fluid potential of the water to be treated and the zeta potential.
As a method of measuring the flow potential of the water to be treated, for example, a method of applying mechanical energy (vibration energy) to the dispersion system and measuring the generated electrical output (see Patent Document 2) is used. Specific methods for applying mechanical energy to this dispersion system include, for example, a method of irradiating colloidal particles with ultrasonic waves, a method of sending a pulsating flow with a pump, a method of mechanically shocking, and the like ( (See Patent Documents 3 to 6).

Next, a conventional streaming potential measuring device that measures the streaming potential of the water to be treated will be specifically described with reference to FIG. 11 (see Patent Document 7). FIG. 11 is a cross-sectional view showing a configuration of a conventional streaming potential measuring device shown in Patent Document 7. In FIG.
As shown in FIG. 11, the conventional streaming potential measuring device 80 is provided so as to be coaxial with the cylinder 84 into which the water to be treated containing colloidal particles flows, and reciprocates in the axial direction of the cylinder 84. A piston 85 that moves, a motor 83 that drives the reciprocating motion of the piston 85, and a pair of ring-shaped electrodes 86a and 86b that are provided on the inner peripheral surface of the cylinder 84 at a distance in the axial direction of the cylinder 84; It has. The pair of electrodes 86a and 86b is connected to a potential difference measuring unit 87 that measures a potential difference generated in the water to be treated between the pair of electrodes 86a and 86b. As the potential difference measuring unit 87, for example, an operational amplifier that amplifies and outputs a potential difference generated in the water to be treated between the pair of electrodes 86a and 86b is used. In addition, a signal amplifier 88 that amplifies the signal sent from the potential difference measuring unit 87 and an amplifier 89 that reduces noise from the signal sent from the signal amplifier 88 are connected in order to the potential difference measuring unit 87.

Next, the operation of the streaming potential measuring device 80 will be described below.
When the motor 83 drives the piston 85 and the piston 85 reciprocates along the axial direction of the cylinder 84, the water to be treated flows through the gap between the cylinder 84 and the piston 85. At this time, a flow potential that is a potential difference between the pair of electrodes 86a and 86b is measured by the potential difference measuring unit 87 connected to the pair of electrodes 86a and 86b, and is measured by the potential difference measuring unit 87. The signal is output to the outside through the signal amplifier 88 and the amplifier 89.

By using this output flow potential of the water to be treated, it is possible to detect a zeta potential proportional to the flow potential, thereby detecting the state of aggregation of colloidal particles in the water to be treated in real time. Can do.
As a flocculant injection control system using such a streaming potential measuring device 80, for example, those disclosed in Patent Documents 8 to 12 are known.

Japanese Patent Laid-Open No. 10-202013 Japanese Patent Laid-Open No. 61-77752 JP-A-5-74776 JP-A-5-74777 Japanese Unexamined Patent Publication No. 7-43334 Japanese Unexamined Patent Publication No. 7-43335 US Pat. No. 3,368,145 JP-A-3-284304 JP-A-3-284305 JP 7-35721 A Japanese Patent Laid-Open No. 8-170956 JP 2002-239307 A

  In the streaming potential measuring device 80 shown in FIG. 11 described above, the motor 83 drives the piston 85, and the piston 85 reciprocates along the axial direction of the cylinder 84. It flows through the gap between 85 and 85. However, when the streaming potential measuring device 80 is used for a long period of time, the axis of the piston 85 may be displaced from the axis of the cylinder 84 due to dirt or the like adhering to the inner peripheral surface of the cylinder 84. When the displacement of the shaft of the piston 85 from the shaft of the cylinder 84 occurs, the size of the gap between the cylinder 84 and the piston 85 becomes different, and it is difficult to stably measure the flow potential of the water to be treated. Become. Further, since the streaming potential measuring device 80 has a complicated structure, there is a problem that the cleaning operation of the inner peripheral surface of the cylinder 84 and the pair of electrodes 86a and 86b is complicated.

  The present invention has been made in consideration of the above points, and has a simple configuration, so that the flow potential of water to be treated can be stably measured even when used for a long time. It is another object of the present invention to provide a streaming potential measuring device that can easily clean an inner peripheral surface of an insulating straight pipe and a pair of electrodes.

  In addition, since the present invention has a simple configuration, it is possible to stably detect the state of aggregation of water to be treated even when used for a long period of time. An object of the present invention is to provide an agglomerated state detection system that can easily perform a cleaning operation of a pair of electrodes and the like.

The present invention is provided so as to form a gap between an insulating straight pipe through which water to be treated flows and an inner peripheral surface of the insulating straight pipe. A core rod extending in the length direction, a pair of electrodes provided in the vicinity of both ends of the core rod in the insulating straight tube, and a potential difference generated in water to be treated between the pair of electrodes and connected to the pair of electrodes A guide member for guiding the flow of water to be treated in the gap between the insulating straight pipe and the core rod, and the inner peripheral surface of the insulating straight pipe and / or the core rod It is provided in the outer peripheral surface of this invention, The streaming potential measuring apparatus characterized by the above-mentioned.
According to such a streaming potential measuring device, it is possible to stably measure the streaming potential of the water to be treated even when used for a long time due to the simple configuration, and also facilitate the cleaning operation. Can be done.
Moreover, the flow of the to-be-processed water in an insulating straight pipe can be stabilized by a guide member, For this reason, the flow potential of to-be-processed water can be measured stably.

  In such a streaming potential measuring device, the size of the gap formed between the insulating straight tube and the core rod is preferably 0.15 mm or more and 0.25 mm or less.

The present invention provides a flat flow channel portion in which the water to be treated is flowed and the cross section of the flow channel is flat, an inlet pipe and an outlet pipe connected to the inlet and outlet of the flat flow channel portion, A pair of electrodes provided in the inlet pipe and the outlet pipe in the vicinity of the inlet and outlet of the flow path section, a potential difference measuring section connected to the pair of electrodes and measuring a potential difference generated in the water to be treated between the pair of electrodes; A streaming potential measuring apparatus comprising:
According to such a streaming potential measuring device, it is possible to stably measure the streaming potential of the water to be treated even when used for a long time due to the simple configuration.

  In such a streaming potential measuring apparatus, it is preferable that the width between a pair of opposing sides in the cross section of the flat flow path portion is 0.15 mm or more and 0.25 mm or less.

In such a streaming potential measuring device, the flat flow path portion is preferably made of an elastic member.
Accordingly, the flat flow channel portion can be freely deformed, and therefore the cleaning operation in the flat flow channel portion can be easily performed.

The present invention is connected to a plurality of flat flow channel portions provided in parallel through which water to be treated is flowed and the cross section of the flow channel is flat, and inlets and outlets of the plurality of flat flow channel portions. Inlet pipes and outlet pipes, a pair of electrodes provided in the inlet pipe and the outlet pipe in the vicinity of the inlet and outlet of each flat channel section, and a pair of electrodes connected to the treated water between the pair of electrodes And a potential difference measuring unit that measures a potential difference to be generated.
According to such a flow potential measuring device, the flow potential of the water to be treated can be stably measured even when used for a long time due to the simple configuration, and the flat flow path portion Therefore, even if a problem such as clogging occurs in one flat flow path portion, measurement of the flow potential of the water to be treated can be performed without interruption.

  In such a streaming potential measuring apparatus, it is preferable that the width between a pair of opposing sides in the cross section of each flat flow path portion is 0.15 mm or more and 0.25 mm or less.

The present invention provides a plurality of circular flow path portions provided in parallel through which water to be treated is flowed and a circular cross section of the flow path, and inlets connected to the inlets and outlets of the plurality of circular flow path portions A pipe and an outlet pipe, a pair of electrodes provided in the inlet pipe and the outlet pipe in the vicinity of the inlet and outlet of each circular flow path section, and a potential difference generated in water to be treated between the pair of electrodes and between the pair of electrodes And a potential difference measuring unit for measuring a fluid potential measuring device.
According to such a streaming potential measuring device, it is possible to stably measure the streaming potential of the water to be treated even when used for a long period of time due to the simple configuration. Therefore, even when a problem such as clogging occurs in one circular flow path portion, measurement of the flow potential of the water to be treated can be performed without interruption.

  In such a streaming potential measuring device, it is preferable that the size of the cross-sectional diameter in each circular flow path portion is 0.15 mm or more and 0.25 mm or less.

  According to the streaming potential measuring apparatus of the present invention, it is possible to stably measure the streaming potential of the water to be treated even when used for a long time due to the simple configuration, and the insulating straight pipe Cleaning of the inner peripheral surface and the pair of electrodes can be easily performed.

  Further, according to the aggregation state detection system of the present invention, it is possible to stably detect the aggregation state of the water to be treated even when used for a long period of time due to the simple configuration, and also the insulating property. Cleaning of the inner peripheral surface of the straight pipe and the pair of electrodes can be easily performed.

First Embodiment FIGS. 1 to 3 are diagrams showing a streaming potential measuring device and an agglomeration state detection system according to a first embodiment of the present invention. Here, FIG. 1 is a sectional view showing the configuration of the streaming potential measuring device according to the first embodiment, and FIG. 2 is a sectional view taken along the line AA of the streaming potential measuring device of FIG. Is a coagulation state detection system using the streaming potential measuring device of FIG.

First, a streaming potential measuring apparatus 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, a streaming potential measuring device 10 is provided with an insulating straight pipe 11 in which treated water containing colloidal particles flows at a constant speed, and an insulating straight pipe 11. A core rod 12 extending in the length direction of the tube 11 and a pair of electrodes 15 a and 15 b provided in the vicinity of the ends 12 a and 12 b of the core rod 12 in the insulating straight tube 11 are provided. In addition, a potential difference measuring unit 18 that measures a potential difference generated in the water to be treated between the pair of electrodes 15a and 15b is connected to the pair of electrodes 15a and 15b.

The insulating straight tube 11 is made of a non-conductive and corrosion-resistant material such as acrylic resin or vinyl chloride resin, and has an inner diameter of, for example, 30 mm and an axial length of, for example, 45 mm. As shown in FIG. 1, core rod holding members 14 and 14 for holding the core rod 12 at the end portions 12 a and 12 b are provided at both ends of the insulating straight tube 11.
Caps 13 and 13 having hollow portions 13a and 13a are attached to the outside of the core rod holding members 14 and 14 by, for example, a screwing method. Each core rod holding member 14 is provided with a plurality of through holes 14a through which water to be treated is circulated, and the internal space of the insulating straight pipe 11 and the hollow portion 13a of the cap 13 communicate with each other through the through holes 14a. ing.
The caps 13 and 13 are provided with hose nipples 16 and 16, and the hose nipples 16 and 16 are removable so that the inlet-side and outlet-side hoses 17 and 17 communicate with the hollow portions 13 a and 13 a of the caps 13 and 13. Is attached.

  The core rod 12 is provided inside the insulating straight tube 11 so as to form a gap between the inner straight surface of the insulating straight tube 11. The core rod 12 is preferably coaxial with the insulating straight tube 11. As described above, the core rod 12 is held by the core rod holding members 14 and 14 at the ends 12a and 12b.

The outer diameter of the core rod 12 is slightly smaller than the inner diameter of the insulating straight tube 11, and specifically, between the outer peripheral surface of the core rod 12 and the inner peripheral surface of the insulating straight tube 11. The width of the gap formed (width a in FIGS. 1 and 2) is not less than 0.15 mm and not more than 0.25 mm.
When the width a of the gap between the insulating straight tube 11 and the core rod 12 is too short, a sufficient amount of water to be treated may pass through the flow path between the insulating straight tube 11 and the core rod 12. It becomes difficult. On the other hand, when the width a of the gap between the insulating straight tube 11 and the core rod 12 is too long, the flow path between the insulating straight tube 11 and the core rod 12 functions as a capillary tube as will be described later. It becomes difficult.
Note that the width a of the gap formed between the outer peripheral surface of the core rod 12 and the inner peripheral surface of the insulating straight tube 11 changes the outer diameter of the core rod 12 or the inner diameter of the insulating straight tube 11. Can be freely adjusted.

  As shown in FIG. 2, a guide member that guides the flow of water to be treated in the gap between the insulating straight pipe and the core rod on the inner peripheral surface of the insulating straight pipe 11 and the outer peripheral surface of the core rod 12. 11c and 12c are provided, respectively. As shown in FIG. 2, the guide members 11 c and 12 c have convex shapes protruding from the inner peripheral surface of the insulating straight tube 11 and the outer peripheral surface of the core rod 12. A concave shape formed by digging a groove in the peripheral surface and the outer peripheral surface of the core rod 12 may be used. Since the guide members 11c and 12c are provided between the insulating straight pipe 11 and the core rod 12, the flow of the water to be treated in the insulating straight pipe 11 can be stabilized. Can be stably measured.

  As shown in FIG. 1, a pair of electrodes 15 a and 15 b are provided in the vicinity of the end portions 12 a and 12 b of the core rod 12 in the insulating straight tube 11. The pair of electrodes 15a and 15b has a ring shape and is mainly made of, for example, silver, copper, platinum, or the like. A pair of electrodes 15a and 15b is connected to a potential difference measuring unit 18 for detecting a flowing potential via a conductive wire 18a. The potential difference measuring unit 18 is a potential difference (fluid potential) generated in the water to be treated between the pair of electrodes 15a and 15b. ). For example, an operational amplifier that amplifies and outputs the potential difference generated in the water to be treated between the pair of electrodes 15a and 15b is actually used as the potential difference measuring unit 18.

  Further, the hose 17 and 17 on the inlet side and the outlet side include the conductivity of the water to be treated flowing in the insulating straight pipe 11, the temperature of the water to be treated and the pressure loss between the electrodes 15a and 15b of the water to be treated. A correction measuring unit 19 for measuring at least one of them is provided. Then, the correction measuring unit 19 sends the measured information to the potential difference measuring unit 18 and corrects the potential difference measured by the potential difference measuring unit 18 based on this information. Thereby, the potential difference measured by the potential difference measuring unit 18 can be corrected according to the state of the water to be treated.

  Next, the whole aggregation state detection system 20 incorporating the streaming potential measuring device 10 according to the present invention having such a configuration will be described with reference to FIG. The agglomeration state detection system 20 detects the agglomeration state of the colloidal particles in the water to be treated sent from the aggregating agent addition facility described later.

  As shown in FIG. 3, the flocculant addition facility is connected to the raw water tank 21 for storing the water to be treated, the flocculant tank 24 for storing the flocculant, and the raw water tank 21 via the raw water feed pump 23. In addition, it has a mixing tank 26 connected to the flocculant tank 24 via a flocculant liquid feed pump 25. In the mixing tank 26, the water to be treated sent from the raw water tank 21 by the raw water feed pump 23 and the flocculant sent from the flocculant tank 24 by the flocculant feed pump 25 are mixed and rapidly stirred. A stirrer 27 is installed. A storage tank 28 for temporarily storing the water to be treated mixed with the flocculant is connected to the downstream side of the mixing tank 26. A device 10 is connected. In this case, the water to be treated stored in the storage tank 28 is sent to the streaming potential measuring device 10 by the liquid feed pump 29.

As the water to be treated stored in the raw water tank 21, for example, a solution in which 50 mg / L of kaolin as colloid particles is dissolved in tap water is used, and this solution is rapidly stirred at 150 rpm by a stirrer 22 provided in the raw water tank 21 for 5 minutes. Stirring is then performed, followed by slow agitation for 15 minutes at 50 rpm by the agitator 22. Further, as the flocculant stored in the flocculant tank 24, for example, 0.5 to 10 mg / L polyaluminum chloride (PAC) is used. The stirrer 27 rapidly stirs the water to be treated and the flocculant mixed in the mixing tank 26 at, for example, about 270 rpm.
Further, the hose 17 of the streaming potential measuring device 10 is connected to the outlet side of the liquid feed pump 29, and for example, the water to be treated in the storage tank 28 is fed through the hose 17 at a speed of 1 liter (L) per minute. It is sent to the streaming potential measuring device 10.

  The agglomeration state detection system 20 incorporates the streaming potential measuring device 10 as described above, and is sent from the aggregating agent addition facility based on the potential difference measured by the potential difference measuring unit 18 of the streaming potential measuring device 10. The state of aggregation of colloidal particles in the water to be treated is detected.

In the aggregation state detection system 20, an amplifier 31 may be connected to the potential difference measuring unit 18 of the streaming potential measuring device 10 as shown in FIG. The amplifier 31 operates when power is supplied from the amplifier power supply 32. The amplifier 31 is also connected to a liquid feed pump 29 of the flocculant addition device, and the liquid feed pump 29 is controlled by the amplifier 31 to start and stop.
The amplifier 31 performs a process of extracting only the component synchronized with the operation of the liquid feeding pump 29 from the signal sent from the potential difference measuring unit 18 of the streaming potential measuring device 10 to reduce noise.
An output from the amplifier 31 is sent to a recorder 33 connected to the amplifier 31.

  Next, the operation of the present embodiment having such a configuration will be described.

  First, the overall operation of the aggregation state detection system 20 will be described. As shown in FIG. 3, the water to be treated which is stored in the raw water tank 21 and stirred by the stirrer 22 is sent to the mixing tank 26 by the raw water feed pump 23. At the same time, the flocculant stored in the flocculant tank 24 is sent to the mixing tank 26 by the flocculant liquid feed pump 25 at a flow rate at which the flocculant injection rate becomes a set value. Next, in the mixing tank 26, a flocculant is added to the water to be treated, and the water to be treated in which the flocculant is mixed is rapidly stirred by the stirrer 27. The liquid mixture that has been rapidly stirred in the mixing tank 26 is sent to the storage tank 28 where it is temporarily stored, and is sent to the streaming potential measuring device 10 by the liquid feed pump 29 in a pulsating flow.

  Next, the operation of the streaming potential measuring device 10 will be described with reference to FIG. In the streaming potential measuring device 10, as shown in FIG. 1, the water to be treated sent from the storage tank 28 through the hose 17 on the inlet side passes through the hollow portion 13 a of the cap 13 on the inlet side and the core rod holding member 14. It is fed into the insulating straight pipe 11 through the through hole 14a. The water to be treated sent to the insulating straight pipe 11 flows in the axial direction of the insulating straight pipe 11 through the gap between the inner peripheral surface of the insulating straight pipe 11 and the outer peripheral surface of the core rod 12. Then, the air is discharged from the hose 17 on the outlet side through the hollow portion 13 a of the cap 13 on the outlet side and the through hole 14 a of the core rod holding member 14.

During this time, the potential difference (flow potential) of the water to be treated between the pair of electrodes 15a and 15b is measured by the potential difference measuring unit 18 connected to the pair of electrodes 15a and 15b via the conductive wire 18a.
Here, the measurement of the flow potential of the water to be treated generally refers to the potential of the water to be treated at a pair of electrodes arranged at a predetermined distance in the capillary by flowing the water to be treated through an insulating capillary. It means to measure the difference.
In the streaming potential measuring device 10 of the present embodiment, instead of flowing the water to be treated into the capillary tube, for example, 0 between the insulating straight tube 11 and the core rod 12 provided in the insulating straight tube 11 is, for example, 0. By flowing the water to be treated through a narrow gap having a size of 15 mm or more and 0.25 mm or less, it is possible to obtain the same operation and effect as when the water to be treated is flowed into the capillary.

  During this time, the correction measuring unit 19 provided in the inlet-side and outlet-side hoses 17, 17 has conductivity of treated water flowing through the insulating straight pipe 11, treated water temperature, and treated water electrode. At least one of the pressure losses between 15a and 15b is measured. Then, the potential difference measured by the potential difference measuring unit 18 is corrected so as to be an appropriate value based on the information measured by the correction measuring unit 19.

  The flow potential signal of the water to be treated measured in the potential difference measuring unit 18 and corrected by the correction measuring unit 19 in this way is sent from the potential difference measuring unit 18 of the streaming potential measuring device 10 to the amplifier 31. The amplifier 31 performs a process of extracting only the component synchronized with the start of the liquid feeding pump 29 from the signal of the flowing potential, and reduces the noise of the signal of the flowing potential. The streaming potential signal processed by the amplifier 31 is sent to a recorder 33, and the recorder 33 records the streaming potential value on a recording sheet, a storage medium, or the like.

  As described above, according to the streaming potential measuring apparatus 10 of the present embodiment, the potential difference of the water to be treated that passes through the gap between the insulating straight tube 11 and the core rod 12 is detected by the pair of electrodes 15a and 15b. Since it has a simple structure, the flow potential of the water to be treated can be measured stably.

  Next, the relationship between the flow potential of the water to be treated and the state of aggregation of the colloidal particles in the water to be treated will be described.

  When the absolute value of the zeta potential (ζ) described later is large, the colloidal particles in the water to be treated have a strong dispersibility because the electrostatic repulsive force becomes strong. On the other hand, when the zeta potential approaches 0, the electrostatic repulsive force is weakened, so that the zeta potential is likely to aggregate. Thus, the aggregation state of colloidal particles can be detected based on the magnitude of the zeta potential.

The zeta potential (ζ) is the potential with respect to the solution bulk of the solution slip surface on the surface of the colloid particles. In the unstable state due to the progress of aggregation of colloid particles, the potential of the solution slip surface on the surface of the colloid particles becomes the potential of the solution bulk. Because they are equal, the zeta potential is almost zero.
The simplified relationship between the flow current (i) of the water to be treated and the zeta potential (ζ) is expressed by the following equation (1) (SK Dentel, Water Supply vol. 9 571-575, 1991). The relationship between the streaming potential (E) and the streaming current (i) is expressed by the following formula (2).

i = -4εζwsR ² / c ² (1)
E = i × R (2)
Here, ε is the dielectric constant of the water to be treated, w is the rotational speed of the drive motor, s is the axial length of the insulating straight tube 11, R is the radius of the core rod 12, and c is the insulating straight tube 11 and the core. This is the size of the gap between the bars 12.

From the above formulas (1) and (2), it can be seen that the zeta potential (ζ) of the water to be treated is proportional to the streaming potential (E).
That is, by measuring the streaming potential of the water to be treated by the streaming potential measuring device 10, the aggregation state of the colloidal particles can be detected based on the zeta potential (ζ) proportional to the streaming potential.

Next, a cleaning method of the streaming potential measuring device 10 will be described.
When the streaming potential measuring device 10 is used for a long period of time, dirt may adhere to the inner peripheral surface of the insulating straight pipe 11 and the electrodes 15a and 15b, and it may be difficult to stably measure the streaming potential of the water to be treated. is there. Therefore, it is necessary to periodically clean the inside of the insulating straight pipe 11.

In cleaning the insulating straight pipe 11, first, the inlet-side and outlet-side hoses 17, 17 are removed from the hose nipples 16, 16 provided on the caps 13, 13. Next, the pair of core rod holding members 14 and 14 and the caps 13 and 13 attached to both ends of the insulating straight tube 11 are removed from the insulating straight tube 11, and then the core rod 12 is removed from the insulating straight tube 11. Pull out.
Then, the inside of the insulating straight pipe 11 in a hollow state is cleaned to remove dirt attached to the inner peripheral surface of the insulating straight pipe 11 and the electrodes 15a and 15b.

Here, in this embodiment, instead of cleaning the inside of the conventional capillary tube having an inner diameter of 10 mm or less, the insulating straight tube 11 having an inner diameter of, for example, 30 mm is cleaned. The inside of the tube 11 can be cleaned.
In disassembling the streaming potential measuring device 10, the pair of core rod holding members 14 and 14 and the caps 13 and 13 are removed, and then the core rod 12 is simply pulled out from the insulating straight tube 11. Therefore, the disassembling work of the streaming potential measuring device 10 for cleaning can be easily performed.

Second Embodiment Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing the configuration of the streaming potential measuring device according to the second embodiment, and FIG. 5 is a sectional view taken along the line BB of the streaming potential measuring device of FIG.

As shown in FIG. 4, the flow potential measuring device 40 according to the present embodiment uses a flat flow path portion 41 having a flat cross section of the flow path instead of using the insulating straight tube 11 and the core rod 12. 1 except that the inlet pipe 42 and the outlet pipe 43 are connected to the inlet 41a and the outlet 41b of the flat channel portion 41, and the other configuration is the first shown in FIGS. This is substantially the same as the embodiment.
In the second embodiment shown in FIG. 4 and FIG. 5, the same parts as those in the first embodiment shown in FIG. 1 and FIG.
The streaming potential measuring device 40 will be described below with reference to FIGS. 4 and 5.

  The flat channel portion 41 is formed by pressing a non-conductive and corrosion-resistant, for example, cylindrical elastic member by a pair of pressing members 44 and 44 from above and below as shown in FIG. The cross section of the channel of the portion 41 has a flat shape elongated in the lateral direction (see FIG. 5). The length of the flat flow path portion 41 in the flow direction is, for example, 45 mm.

As shown in FIG. 5, the cross section of the flat channel portion 41 has a flat shape, and includes a pair of parallel sides b1 facing each other and a pair of semicircular portions b2 provided at both ends of the pair of sides b1. Thus, the width b between the pair of opposing sides b1 is not less than 0.15 mm and not more than 0.25 mm. When the width b is too short, it becomes difficult for a sufficient amount of water to be treated to pass through the flat flow path portion 41. In addition, when the width b is too long, it becomes difficult for the flat channel portion 41 to function as the aforementioned capillary tube.
The width b between a pair of opposing sides b1 in the cross section of the flat channel portion 41 can be freely adjusted by changing the pressing force of the pressing members 44, 44 against the flat channel portion 41.

As shown in FIG. 4, an inlet pipe 42 made of a non-conductive and corrosion-resistant sealed body and an outlet pipe 43 made of a sealed body are connected to the inlet 41 a and the outlet 41 b of the flat channel portion 41. The inlet pipe 42 and the outlet pipe 43 are provided with hose nipples 16, 16. The hose nipples 16, 16 communicate with the inlet side and outlet side hoses 17, 17 in the inlet pipe 42 and the outlet pipe 43, respectively. It is attached so that it can be removed.
The pair of electrodes 15 a and 15 b are respectively provided in the inlet pipe 42 and the outlet pipe 43 in the vicinity of the inlet 41 a and the outlet 41 b of the flat channel portion 41.

  Next, the operation of the present embodiment having such a configuration will be described.

  As shown in FIG. 4, the water to be treated sent from the hose 17 on the inlet side is first sent into the inlet pipe 42 via the hose nipple 16, and then sent to the flat flow path portion 41. Furthermore, the water to be treated from the flat flow channel portion 41 is sent to the outlet pipe 43 and discharged from the hose 17 on the outlet side.

During this time, the potential difference (flow potential) of the water to be treated between the pair of electrodes 15a and 15b is detected by the potential difference measuring unit 18 connected to the pair of electrodes 15a and 15b via the conductive wire 18a.
In the streaming potential measuring device 40 of the present embodiment, instead of flowing the water to be treated through the capillary, the width b between a pair of opposite sides b1 in the cross section is, for example, 0.15 mm or more and 0.25 mm or less. By flowing the water to be processed through the flow path of the flat flow path portion 41, the same effect as that when the water to be processed is flowed into the capillary described in the first embodiment can be obtained.

  As described above, according to the streaming potential measuring device 40 of the present embodiment, the potential difference of the water to be treated that passes through the flat flow channel portion 41 that is deformed by being pressed from above and below by the pressing members 44, 44 is determined as a pair of electrodes 15a. 15b, the flow potential of the water to be treated can be stably measured.

Next, a cleaning method of the streaming potential measuring device 40 will be described.
In the cleaning of the flat flow path portion 41 in the streaming potential measuring device 40, first, the inlet-side and outlet-side hoses 17, 17 are removed from the hose nipples 16, 16 provided in the inlet pipe 42 and the outlet pipe 43. Next, the pressing members 44 and 44 that press the flat flow channel portion 41 from above and below are separated from the flat flow channel portion 41, and the shape of the flat flow channel portion 41 is returned to the original cylindrical shape, for example.
Then, the flat channel portion 41 that has returned to its original shape is cleaned to remove the dirt adhering to the inner surface of the flat channel portion 41 and the pair of electrodes 15a and 15b.

  After the cleaning is completed, the flat flow channel portion 41 that has returned to the original cylindrical shape, for example, is again pressed from above and below by the pressing members 44, 44. The flat flow channel portion 41 has a cross section as shown in FIG. Return to a flat shape.

  As described above, in the present embodiment, the flat flow path portion 41 is made of an elastic member, so that the flat flow path portion 41 having a flat cross section is returned to the original cylindrical shape and washed. In addition, the inside of the flat flow channel portion 41 can be easily cleaned, and it can be returned to the one having the flat cross section again after the cleaning.

Third Embodiment Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a cross-sectional view showing the configuration of the streaming potential measuring device according to the third embodiment, and FIG. 7 is a sectional view taken along the line CC of the streaming potential measuring device of FIG.

As shown in FIG. 6, the streaming potential measuring device 50 according to the present embodiment is provided in parallel instead of using the insulating straight tube 11 and the core rod 12 so that the cross section of the flow path has a flat shape. It has a plurality of flat flow channel portions 51, except that the inlet pipe 52 and the outlet pipe 53 are connected to the inlet 51a and the outlet 51b of the plurality of flat flow channel portions 51. This is substantially the same as the first embodiment shown in FIGS.
In the third embodiment shown in FIG. 6 and FIG. 7, the same parts as those in the first embodiment shown in FIG. 1 and FIG.
The streaming potential measuring device 50 will be described below with reference to FIGS. 6 and 7.

  The plurality of flat flow channel portions 51 are made of a non-conductive and corrosion-resistant material such as acrylic resin or vinyl chloride resin, and the cross sections of the flow channels each have a flat shape elongated in the horizontal direction (see FIG. 7). It has become. The length of each flat channel portion 51 in the flow direction is, for example, 45 mm.

  7 has a flat shape, and includes a pair of parallel sides c1 facing each other and a pair of semicircular portions c2 provided at both ends of the pair of sides c1. The width c between the pair of opposing sides c1 is 0.15 mm or more and 0.25 mm or less. When the width c is too short, it becomes difficult for a sufficient amount of water to be treated to pass through the flat flow channel portions 51. Moreover, when this width | variety c is too long, it will become difficult for each flat flow path part 51 to fulfill | perform the function as a capillary tube mentioned above.

As shown in FIG. 5, a non-conductive and corrosion-resistant inlet pipe 52 and outlet pipe 53 are connected to the inlet 51 a and the outlet 51 b of each flat channel portion 51. The inlet pipe 52 and the outlet pipe 53 form a sealed space inside, and the space in the inlet pipe 52 and the space in the outlet pipe 53 are communicated with each other by a plurality of flat channel portions 51. The inlet pipe 52 and the outlet pipe 53 are provided with hose nipples 16, 16, respectively, and the inlet side and outlet side hoses 17, 17 are respectively attached via the hose nipples 16, 16.
The pair of electrodes 15a and 15b are respectively provided in the inlet pipe 52 and the outlet pipe 53 in the vicinity of the inlet 51a and the outlet 51b of each flat channel portion 51.

  Next, the operation of the present embodiment having such a configuration will be described.

  As shown in FIG. 6, the water to be treated sent from the hose 17 on the inlet side is first sent into the inlet pipe 52 through the hose nipple 16, and then each flat flow path portion 51 provided in parallel. Branched to and sent. Furthermore, the water to be treated from each flat flow channel portion 51 gathers again, is sent to the outlet pipe 53, and is discharged from the hose 17 on the outlet side.

During this time, the potential difference (flow potential) of the water to be treated between the pair of electrodes 15a and 15b is detected by the potential difference measuring unit 18 connected to the pair of electrodes 15a and 15b via the conductive wire 18a.
In the streaming potential measuring device 50 of the present embodiment, instead of flowing the water to be treated into the capillary, a plurality of narrownesses in which the width c between a pair of opposing sides c1 is, for example, 0.15 mm or more and 0.25 mm or less. By branching into the flow path of the flat flow channel portion 51 and flowing the water to be treated, the same effect as that when the water to be treated is flowed into the capillary described in the first embodiment can be obtained. Yes.

  As described above, according to the streaming potential measuring device 50 of the present embodiment, the potential difference of the water to be treated that passes through the plurality of flat flow channel portions 51 is detected by the pair of electrodes 15a and 15b. Therefore, the flow potential of the water to be treated can be measured stably. In addition, since a plurality of flat flow channel portions 51 are provided, even if a problem such as clogging occurs in one flat flow channel portion 51, the measurement of the flow potential of the water to be treated is performed without interruption. be able to.

Fourth Embodiment Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a cross-sectional view showing the configuration of the streaming potential measuring device according to the fourth embodiment, and FIG. 9 is a sectional view taken along the line DD of the streaming potential measuring device of FIG.

As shown in FIG. 8, the streaming potential measuring device 60 according to the present embodiment uses a plurality of parallel flow paths having a circular cross section instead of using the insulating straight tube 11 and the core rod 12. It has a circular flow passage 61, and the only difference is that the inlet pipe 62 and the outlet pipe 63 are connected to the inlet 61a and the outlet 61b of the plurality of circular flow passages 61, and the other configuration is shown in FIG. And it is substantially the same as 1st Embodiment shown in FIG.
In the fourth embodiment shown in FIGS. 8 and 9, the same parts as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
The streaming potential measuring device 60 will be described below with reference to FIGS. 8 and 9.

  The plurality of circular flow path portions 61 are made of a non-conductive and corrosion-resistant material such as acrylic resin or vinyl chloride resin, and the cross sections of the flow paths are circular (see FIG. 9). The length of each circular flow path 61 in the flow direction is 45 mm, for example.

  The diameter d of the cross section of each circular flow path part 61 shown in FIG. 9 is 0.15 mm or more and 0.25 mm or less. When the diameter d of this cross section is too short, it becomes difficult for a sufficient amount of water to be treated to pass through each circular flow path portion 61. Moreover, when this diameter d is too long, it becomes difficult for each circular flow path part 61 to fulfill | perform the function as a capillary tube mentioned above.

As shown in FIG. 8, a non-conductive and corrosion-resistant inlet pipe 62 and outlet pipe 63 are connected to the inlet 61 a and outlet 61 b of each circular flow path portion 61. The inlet pipe 62 and the outlet pipe 63 form a sealed space inside, and the space in the inlet pipe 62 and the space in the outlet pipe 63 communicate with each other by a plurality of circular flow passage portions 61. . The inlet pipe 62 and the outlet pipe 63 are provided with hose nipples 16, 16, respectively. The inlet side and outlet side hoses 17, 17 are respectively attached via the hose nipples 16, 16.
The pair of electrodes 15 a and 15 b are respectively provided in the inlet pipe 62 and the outlet pipe 63 in the vicinity of the inlet 61 a and the outlet 61 b of each circular flow path portion 61.

  Next, the operation of the present embodiment having such a configuration will be described.

  As shown in FIG. 8, the water to be treated sent from the hose 17 on the inlet side is first sent into the inlet pipe 62 through the hose nipple 16, and then each circular flow path portion 61 provided in parallel. Branched to and sent. Furthermore, the water to be treated from each circular flow path portion 61 gathers again, is sent to the outlet pipe 63, and is discharged from the hose 17 on the outlet side.

During this time, the potential difference (flow potential) of the water to be treated between the pair of electrodes 15a and 15b is detected by the potential difference measuring unit 18 connected to the pair of electrodes 15a and 15b via the conductive wire 18a.
In the streaming potential measuring device 60 of the present embodiment, instead of flowing the water to be treated into the capillary, a plurality of narrow circular flows having a circular shape with a diameter d of, for example, 0.15 mm or more and 0.25 mm or less. By branching into the flow path of the passage portion 61 and flowing the water to be treated, the same effect as that in the case of flowing the water to be treated through the capillary described in the first embodiment can be obtained.

  As described above, according to the streaming potential measuring device 60 of the present embodiment, it has a simple structure in which the potential difference of the water to be treated that passes through the plurality of circular flow passage portions 61 is detected by the pair of electrodes 15a and 15b. Therefore, the flow potential of the water to be treated can be measured stably. In addition, since a plurality of circular flow path portions 61 are provided, even if a problem such as clogging occurs in one circular flow path portion 61, measurement of the flow potential of the water to be treated should be performed without interruption. Can do.

  Hereinafter, examples and comparative examples of the streaming potential measuring apparatus of the present invention will be described with reference to FIG. This example corresponds to the first embodiment shown in FIGS. FIG. 10 shows the flow potential (SCD value) of the water to be treated measured using the streaming potential measurement device according to the first embodiment and the flow potential of the water to be treated measured using the conventional streaming potential measurement device. It is a graph shown over time.

Graph A in FIG. 10 shows the flow potential measured by the flow potential measuring apparatus 10 (see FIG. 1) according to the first embodiment over time for the water to be treated sent from the flocculant addition facility shown in FIG. It is a graph shown in.
More specifically, first, a kaolin suspension having a turbidity of 50 mg / L in the raw water tank 21 is sufficiently stirred by the stirrer 22 and sent to the mixing tank 26 by the raw water feed pump 23 at 4 liters per minute. At the same time, the flocculant made of polyaluminum chloride (PAC) stored in the flocculant tank 24 and having a specific gravity of 1.2416 is sent to the mixing tank 26 by the flocculant liquid feed pump 25 at a rate of 20 ml / min.
In the mixing tank 26, the water to be treated to which the flocculant is added is rapidly stirred by a stirrer 27 at 270 rpm, and the stirred water to be treated is sent to the storage tank 28 and temporarily stored. And the to-be-processed water stored in the storage tank 28 is sent to the streaming potential measuring apparatus 10 by the pulsating flow by the liquid feeding pump 29. FIG.

  In the streaming potential assumption apparatus 10, the potential difference of the water to be treated between the pair of electrodes 15 a and 15 b is measured by the potential difference measuring unit 18. The streaming potential signal measured by the potential difference measuring unit 18 is sent to the amplifier 31, and the streaming potential signal processed by the amplifier 31 is sent to the recorder 33. The change with time of the streaming potential recorded by the recorder 33 is shown in graph A of FIG.

A graph B in FIG. 10 shows the conventional streaming potential measuring apparatus shown in FIG. 11 instead of using the streaming potential measuring apparatus 10 according to the first embodiment for the water to be treated sent from the flocculant addition facility shown in FIG. 8 is a graph of a comparative example showing the streaming potential measured using 80 over time.
In this comparative example, the flocculant addition equipment shown in FIG. 3 is the same as the flocculant addition equipment in the above-described embodiment.

  According to the graph A according to the embodiment of FIG. 10 and the graph B according to the comparative example, in the streaming potential measuring device of the present invention, the variation in the measured value of the streaming potential is small compared to the conventional streaming potential measuring device, and the processing is stably performed. It can be seen that the flow potential of water can be measured.

Sectional drawing which shows the structure of the streaming potential measuring device by the 1st Embodiment of this invention AA arrow sectional view of the streaming potential measuring device of FIG. Aggregation state detection system using flocculant addition facility and streaming potential measuring device of FIG. Sectional drawing which shows the structure of the streaming potential measuring device by the 2nd Embodiment of this invention BB arrow sectional view of the streaming potential measuring device of FIG. Sectional drawing which shows the structure of the streaming potential measuring device by the 3rd Embodiment of this invention CC arrow sectional drawing of the streaming potential measuring device of FIG. Sectional drawing which shows the structure of the streaming potential measuring device by the 4th Embodiment of this invention DD arrow sectional view of the streaming potential measuring device of FIG. The graph which shows the Example and comparative example of this invention Sectional drawing which shows the structure of the conventional streaming potential measuring device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Streaming potential measuring apparatus 11 Insulating straight pipe 11c Guide member 12 Core rod 12a, 12b End part 12c Guide member 13 Cap 13a Hollow part 14 Core rod holding member 14a Through-hole 15a, 15b A pair of electrode 16 Hose nipple 17 Hose 18 Potential difference Measuring unit 18a Conducting wire 19 Correction measuring unit 20 Aggregation state detection system 21 Raw water tank 22 Stirrer 23 Raw water feed pump 24 Coagulant tank 25 Coagulant feed pump 26 Mixing tank 27 Stirrer 28 Storage tank 29 Feed pump 31 Amplifier 32 Amplifier power supply 33 Recorder 40 Streaming potential measuring device 41 Flat channel portion 41a Inlet 41b Outlet 42 Inlet tube 43 Outlet tube 44 Pressing member 50 Streaming potential measuring device 51 Flat channel portion 51a Inlet 51b Outlet 52 Inlet tube 53 Outlet tube 60 Flow Potential measuring device 61 Circular flow passage 61a Inlet 61b Outlet 62 Mouth tube 63 outlet tube 80 streaming potential measuring device 83 motor 84 cylinder 85 piston 86a, 86b a pair of electrodes 87 potential difference measuring unit 88 a signal amplifier 89 amplifier

Claims (9)

An insulating straight pipe through which the water to be treated flows;
A core rod provided inside the insulating straight pipe so as to form a gap between the inner peripheral surface of the insulating straight pipe and extending in the length direction of the insulating straight pipe;
A pair of electrodes provided in the vicinity of both ends of the core rod in the insulating straight pipe,
A potential difference measuring unit connected to the pair of electrodes and measuring a potential difference generated in the water to be treated between the pair of electrodes;
With
A guide member for guiding the flow of water to be treated in the gap between the insulating straight pipe and the core rod is provided on the inner peripheral surface of the insulating straight tube and / or the outer peripheral surface of the core rod. Streaming potential measuring device.   2. The streaming potential measuring device according to claim 1, wherein the size of the gap formed between the insulating straight pipe and the core rod is not less than 0.15 mm and not more than 0.25 mm. A flat flow channel portion in which the water to be treated is flowed and the cross section of the flow channel is flat,
An inlet pipe and an outlet pipe connected to the inlet and outlet of the flat flow path section;
A pair of electrodes provided in the inlet pipe and the outlet pipe in the vicinity of the inlet and outlet of the flat channel section;
A potential difference measuring unit connected to the pair of electrodes and measuring a potential difference generated in the water to be treated between the pair of electrodes;
A streaming potential measuring apparatus comprising:   4. The streaming potential measuring device according to claim 3, wherein a width between a pair of opposing sides in a cross section of the flat flow path portion is 0.15 mm or more and 0.25 mm or less.   5. The streaming potential measuring device according to claim 3, wherein the flat channel portion is made of an elastic member. A plurality of flat flow path portions provided in parallel, in which the water to be treated is flowed and the cross section of the flow path is a flat shape,
An inlet pipe and an outlet pipe connected to the inlet and outlet of the plurality of flat flow path portions;
A pair of electrodes provided in the inlet pipe and the outlet pipe in the vicinity of the inlet and outlet of each flat channel section;
A potential difference measuring unit connected to the pair of electrodes and measuring a potential difference generated in the water to be treated between the pair of electrodes;
A streaming potential measuring apparatus comprising:   The flow potential measuring device according to claim 6, wherein a width between a pair of opposing sides in a cross section of each flat channel portion is 0.15 mm or more and 0.25 mm or less. A plurality of circular flow path portions provided in parallel in which the water to be treated is flowed and the cross section of the flow path is circular;
An inlet pipe and an outlet pipe connected to the inlets and outlets of the plurality of circular flow path portions;
A pair of electrodes provided in the inlet pipe and the outlet pipe in the vicinity of the inlet and outlet of each circular flow path section;
A potential difference measuring unit connected to the pair of electrodes and measuring a potential difference generated in the water to be treated between the pair of electrodes;
A streaming potential measuring apparatus comprising:   9. The streaming potential measuring device according to claim 8, wherein a diameter of a cross section in each circular flow path portion is 0.15 mm or more and 0.25 mm or less.

Images