JP3838099B2 - Water quality measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water quality measuring device, and more particularly to a water quality measuring device having a water quality sensor.
[0002]
[Prior art]
In a water quality measuring apparatus having a water quality sensor, the water quality sensor is normally embedded in a pipe and cannot be removed while water is flowing.
[0003]
The reason why the water quality sensor is provided directly in the pipe and cannot be removed is to prevent measurement errors due to the following (1) and (2).
(1) Like the specific resistance of ultrapure water, when touching the outside, the numerical value may change and accurate measurement may not be possible.
(2) If the flow rate, pressure and flow (= laminar flow) are not constant, the sensor may react sensitively due to its good sensitivity, and stable measurement may not be possible.
[0004]
In addition, the water quality measuring device is normally operated by a power supply of AC 100V, as in general equipment. The signal detected by the water quality sensor is displayed on the water quality measurement device, and the integrated amount is calculated from the start of water flow by the arithmetic device, and if there is a chemical injection device, the numerical value is fed back to control the chemical injection amount. Or
[0005]
[Problems to be solved by the invention]
In the conventional water quality measuring device, since the water quality sensor is directly attached to a pipe through which water for measuring the water quality flows, the sensor cannot be easily replaced. In particular, a water quality sensor that operates non-stop like an ultrapure water device is difficult to calibrate as well as to be replaced. In addition, when installing a new water quality measurement device in an existing water treatment device to directly attach the water quality sensor to the pipe, stop the water flow, cut the pipe and replace it with one that has a mounting part. Or had to make a hole and insert a sensor, which required extensive work. Although it is conceivable to use a sample pipe etc. to provide an external sensor, this method involves attaching a thin pipe to the thick main pipe, so the water flowing from the thick main pipe into the thin pipe is turbulent. Since it is easy to become, and it is easy to receive the fluctuation | variation of a pressure, the measurement of a sensor cannot be performed stably and an exact measurement result cannot be obtained.
[0006]
In addition, the water quality measuring device requires a power source for the operation of the water quality sensor. For this reason, there is no particular problem in the case of a new installation, but when installing a new water quality measurement device to an existing device or when installing a water quality measurement device in a new system that is a modification of the existing device, It is necessary to redraw the power supply wiring, increase the number of power distribution boards, and enormous costs for the power supply work. In particular, in a clean room installed in a semiconductor factory, a pharmaceutical manufacturing factory, or a food / drinking water processing manufacturing factory, it is difficult to install a water quality measuring device because such work / construction itself is difficult.
[0007]
The present invention solves the above-mentioned conventional problems, can be easily attached to and detached from the main pipe to which water to be measured for water quality is transferred, and can perform stable water quality measurement by a water quality sensor. , Providing a water quality measuring device that can be easily operated even in places where it is difficult to secure a power supply, and therefore can be easily attached to and detached from existing water treatment equipment, and the maintenance of water quality sensors can be easily performed The purpose is to do.
[0008]
[Means for Solving the Problems]
The water quality measuring device of the present invention includes a sample water pipe connected to a main pipe through which water to be measured for water quality is transferred, a water quality sensor installed in the sample water pipe, and a sample water pipe upstream of the water quality sensor. a rotary impeller provided, possess a straight pipe section having a downstream and at least 5cm length of arranged immediately in front of the water quality sensor of the rotating impeller, the rotational force of the rotating impeller power generator is transmitted is characterized that you have provided.
[0009]
As described above, when a narrow pipe is pulled from the main pipe, the water flowing in the pipe becomes turbulent and the pressure becomes unstable. As a result, pulsation occurs and measurement by the water quality sensor becomes unstable. In the present invention, a rotating impeller is installed on the upstream side of the water quality sensor, and the flow of water from the main pipe is received by the impeller, thereby suppressing the occurrence of this pulsation. And, by providing a straight pipe section with a length of 5 cm or more immediately before the water quality sensor on the downstream side of the rotary impeller, water quality measurement with the same stability and accuracy as when the water quality sensor is installed in the main pipe is performed. Can be done. In addition, providing a straight piping part just before a water quality sensor means connecting a water quality sensor directly to this linear piping part. It is more preferable that the straight pipe portion is installed in the horizontal direction and connected to the water quality sensor.
[0010]
Further, by providing a rectifying means between the water quality sensor and the rotary impeller, the stability of measurement by the water quality sensor can be further enhanced. In this case, the rectifying means may be any means that can cause a pressure loss in the water flow, and a filling portion filled with a filling, a U-shaped tube or a coiled tube, and other meandering flow path portions are applied. be able to. Due to the pressure loss due to such rectifying means, the flow of water is rectified and becomes homogeneous.
[0011]
In general, the water quality sensor is affected by temperature and the measured value changes. Therefore, the measurement is preferably performed under a constant temperature condition. For this reason, it is preferable to provide a temperature adjusting means on the upstream side of the water quality sensor to keep the measurement temperature constant.
[0012]
In the present invention, by applying a braking force to the rotating impeller, it is possible to sufficiently suppress the pulsation of the water flow and stabilize the water flow in the sample water pipe. In order to apply such a braking force, the power generator can be attached directly to the shaft of the impeller or via a gear or a belt.
[0013]
The electric power generated by this power generator may be used as a driving power source for the water quality sensor. By using this generated power as a power source for the water quality sensor, the power distribution work required for driving the water quality sensor becomes unnecessary, and not only the construction cost can be reduced, but also the construction time can be shortened.
[0014]
By the way, the water quality sensor may be deteriorated by dissolved oxygen in the water, and the measurement accuracy may deteriorate with time. In other words, the water quality sensor usually senses fluctuations in water quality using the electrical properties of various metals, but the metal in the sensor reacts with dissolved oxygen to form an oxide film on the surface, gradually measuring accuracy. Changes.
[0015]
Therefore, in the present invention, it is preferable to provide a dissolved oxygen removing means in the pipe upstream of the water quality sensor. As the dissolved oxygen removing means, a deoxygenation catalyst or a deaeration device can be used. The deoxygenation catalyst reacts dissolved oxygen and hydrogen on the catalyst surface to reduce the dissolved oxygen concentration. Note that the degassing device can efficiently remove dissolved oxygen even when the fluctuation range of dissolved oxygen in water is large or from wastewater containing a large amount of dirt components.
[0016]
The present invention includes, for example, industrial facilities such as various factories and power plants, public facilities such as schools and hospitals, government offices, corporate buildings, residential facilities such as condominiums and hotels, amenity facilities such as bathing facilities and pools, department stores and restaurants, etc. Water used in laundry facilities such as complex facilities with food and beverages, dyeing workshops and laundry shops, water quality management of wastewater such as industrial wastewater or household wastewater discharged from these facilities, water treatment or wastewater treatment equipment Although it can be used for water quality management, it can be applied to other than these.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the water quality measuring device of the present invention will be described below in detail with reference to the drawings.
[0018]
FIG. 1 is a system diagram showing an embodiment of the water quality measuring apparatus of the present invention.
[0019]
FIG. 1 shows a water quality measuring device according to the present invention provided in a subsystem of an ultrapure water production system. In this subsystem, primary pure water from the primary pure water system is introduced into the primary pure water tank 11, and an ultraviolet (UV) oxidizer 13, a mixed bed ion exchanger 14, and ultrafiltration (UF) are pumped 12. Ultrapure water is produced by being processed by the membrane separator 15. The produced ultrapure water is supplied from the pipe 16 to the use point 17, and surplus ultrapure water that has not been used at the use point 17 is returned from the pipe 18 to the primary pure water tank 11 to be circulated.
[0020]
The water quality measuring device 1 includes a sample water pipe 2 connected to an ultrapure water pipe (hereinafter referred to as “main pipe”) 16 of a subsystem, a rotary impeller 3, a straight pipe section 4, and a water quality sensor 5. ing. The rotating impeller 3 is provided with a power generator 6. In this water quality measuring device 1, the flow of ultrapure water that has flowed into the sample water pipe 2 from the main pipe 16 is stabilized by the rotary impeller 3 to suppress the occurrence of pulsation, and the water flow is stabilized by the straight pipe section 4. The water quality is measured by the water quality sensor 5 as a stable water flow without pulsation. In addition, although the electric power generating apparatus 6 attached to the rotary impeller 3 generate | occur | produces electricity by rotation of the rotary impeller 3 by a water flow, this electric power is utilized as a drive source of a water quality sensor. The sample water whose water quality is measured by the water quality sensor 5 is discharged out of the system.
[0021]
Any type of impeller may be used, but an axial flow type is preferable.
[0022]
A water flow can be fully stabilized by making the linear piping part 4 into 5 cm or more. About 5-30 cm is sufficient for the length of this linear piping part 4. In addition, this linear piping part 4 is preferably arrange | positioned horizontally.
[0023]
Examples of the water quality sensor 5 include those that measure the electrical conductivity or specific resistance of water, those that detect ion concentration in water, those that measure all organic carbon components in water, those that measure the dissolved oxygen concentration in water, Those that measure the dissolved hydrogen concentration, those that measure the dissolved ozone concentration in water, those that measure the oxidation-reduction potential of water, and those that measure the acidity (= pH) of water can be used. It is not limited to.
[0024]
Since the water quality measuring device of the present invention performs measurement by introducing water to be measured from the main pipe 16 to the sample water pipe 2, long-term stability can be realized, but more reliable measurement is performed. Therefore, it is desirable to periodically calibrate the water quality sensor. For this reason, the water quality measuring device may be portable and the device can be taken home and calibrated.
[0025]
An example of this portable water quality measuring apparatus is shown in FIG. FIG. 2A shows a sample water introduction unit 21 incorporating the rotary impeller 3 and the power generation device 6, the straight pipe portion 4, the water quality sensor 5, the power from the power generation device 6 and the water quality sensor 5. The measurement result can be divided into four parts with the main body 22 having the display 22A. FIG. 2 (b) shows two parts of the rotary impeller 3, the straight pipe portion 4, the water quality sensor 5 and the sample water introduction / measurement portion 23 incorporating the power generation device 6, and the main body portion 22 having the display portion 22A. It can be divided into FIG. 2 (c) shows that the rotary impeller 3, the straight pipe portion 4, the water quality sensor 5, the power generator 6, the calculator 24 to which the measurement result of the water quality sensor 5 is input, the power source 25, and the display portion 26 are integrated. It is the water quality measuring device 30 made.
[0026]
In the present invention, it is preferable to provide a rectifying means between the water quality sensor 5 and the rotary impeller 3 in order to suppress disturbance of the water flow in the sample water pipe 2 and further stabilize the water flow. As the rectifying means, any means capable of causing a pressure loss in the water flow may be used, and a filling portion filled with a filling, a U-shaped tube or a coiled tube, and other meandering flow path portions may be applied. Can do.
[0027]
The filler filled in the filling portion may be anything as long as it does not contaminate the water to be measured, and examples thereof include granular materials such as synthetic resins, metals, and ceramics, and meshes. The filler may be activated carbon or ion exchange resin if it does not affect the measured water quality item.
[0028]
Since the water quality sensor 5 is generally affected by temperature and the measured value changes, the measurement is preferably performed under a constant temperature condition. For this purpose, a temperature adjusting means is provided on the upstream side of the water quality sensor 5 as necessary. May be. As the temperature adjusting means, a thermostatic bath or a jacket in which a heat medium is circulated can be used. For example, a device in which piping is passed through the thermostatic bath can be adopted. In this case, as shown in FIG. 3, a constant temperature bath in which a coiled tube (which may be a V-shaped tube or a meandering flow path) 7A is passed between the rotary impeller 3 and the straight pipe portion 4. 7 and by passing a heating medium through the thermostatic chamber 7, the water flow of the water to be measured may be rectified and the temperature may be adjusted to be constant. Thus, by providing a curved pipe such as the U-shaped pipe 7A in the thermostat 7, the heat exchange part can be made longer than the straight pipe, and the temperature control effect is enhanced. In FIG. 3 and FIGS. 4 and 5 to be described later, members having the same functions as those shown in FIG.
[0029]
In order to prevent the water quality sensor 5 from being affected by dissolved oxygen, a dissolved oxygen removing means may be provided on the upstream side of the water quality sensor 5.
[0030]
As the dissolved oxygen removing means, a deoxygenation catalyst for reacting dissolved oxygen and hydrogen in the water to be measured can be used. Any deoxygenation catalyst may be used as long as hydrogen and oxygen can react with each other, but Pd that selectively exhibits catalytic action is preferable. The deoxygenation catalyst is often used by supporting a catalytic metal using zeolite or the like as a carrier. However, as for Pd, there is a commercially available product supported on an anion exchange resin, and this may be used.
[0031]
There is no particular restriction on the injection location of hydrogen to be reacted with dissolved oxygen in the water to be measured, but hydrogen is more evenly dispersed by the stirring effect of the rotary impeller 3 by being injected upstream of the rotary impeller 3. Can be made.
[0032]
FIG. 4 shows a water quality measuring device provided with such a means for removing dissolved oxygen using a deoxygenation catalyst. A hydrogen gas cylinder 8 for injecting hydrogen into the sample water pipe 2 and a deoxygenation catalyst packed tower 9 are provided. The measurement water into which hydrogen has been injected from after passing through the rotary impeller 3 is introduced into the deoxygenation catalyst packed tower 9 and the dissolved oxygen is removed by the reaction of dissolved oxygen and hydrogen in the measurement water. Has been.
[0033]
The dissolved oxygen removing means may be a deaeration device that physically removes dissolved oxygen. Although there is no restriction | limiting in particular as this deaeration apparatus, Since the membrane deaeration apparatus using a deaeration membrane is compact and the dissolved oxygen concentration contained in to-be-measured water can be reduced efficiently, it is preferable.
[0034]
FIG. 5 shows a water quality measuring device provided with such a degassing device. The water to be measured that has flowed into the sample water pipe 2 is freed of dissolved oxygen by the degassing device 10, and then the rotating impeller 3 and the linear shape are measured. It is fed to the water quality sensor 5 through the piping part 4.
[0035]
In addition, when a deaeration device as a dissolved oxygen removal unit is provided, a unit for preventing the adhesion of dirt to the deaeration device may be provided in order to maintain the performance. For example, a sand filtration device or a membrane (microfiltration membrane or ultrafiltration membrane) separation device is provided on the upstream side of the deaeration device to remove dirt components of the water to be measured.
[0036]
In the present invention, the water quality sensor 5 may be provided in the sample water pipe or in a tank connected to the sample water pipe. For example, the accuracy of a pH meter becomes unstable when continuously measured in a flowing state, but this problem can be solved if the sensor is installed in a tank where water to be measured stays for 10 seconds or more.
[0037]
In general, a water quality measuring device is often remotely monitored in a central control room or the like. For this reason, in the water quality measuring apparatus of this invention, it is preferable to enable it to output the measured value of a water quality sensor as an electrical signal outside. In this case, in view of the ease and accuracy of signal processing, it is preferable that the voltage output is used when the transmission distance is several meters to several tens of meters, and the current output is used when the distance is longer. Furthermore, in the case of long-distance transmission exceeding several hundred meters, wireless transmission is preferable.
[0038]
Each water quality data from the water quality measuring device of the present invention can be fed back to a separately installed medication injection device to control the dose.
[0039]
Moreover, in the desalination apparatus and softening apparatus using ion exchange resins, such as an ultrapure water or a pure water production system, when the ion exchange capability falls, regeneration with a regenerant is performed. The timing of regeneration may be judged by the quality of the treated water, but recently, the quality of the inlet water is monitored over time, and the life is predicted by calculating the load with a computing device. The water quality measuring device of the present invention is also suitably used as a water quality measuring device for predicting the life of such an ion exchange resin.
[0040]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0041]
Example 1
As shown in FIG. 1, the water quality measuring device 1 of the present invention was attached to an ultrapure water pipe (water supply pressure 0.3 MPa) 16 of a subsystem of the ultrapure water production system, and the specific resistance of ultrapure water was measured. .
[0042]
As the sample water pipe 2, a 10 mmφ polytetrafluoroethylene tube is used. Ultrapure water is taken out from the ultrapure water pipe 16 at 200 L / hr, and the rotary impeller 3, the horizontal straight pipe part 4 having a length of 5 cm, and the water quality sensor are used. (Resistivity sensor) The water was passed through 5, and the specific resistance was continuously measured over 24 hours. As the rotary impeller 3, a blade having a diameter of 45 mm, the number of blades of 13 and a blade having a receding angle of 17 ° was used. As a specific resistance sensor, a specific resistance meter “MX-4” manufactured by Kurita Kogyo Co., Ltd. was used.
[0043]
The measurement result of the specific resistance at this time is shown in FIG.
[0044]
The ultra-pure water pipe 16 of the subsystem is provided with a similar specific resistance sensor in advance, and the measured values measured by this specific resistance sensor (existing sensor) are also shown in FIG.
[0045]
Comparative Example 1
The same procedure as in Example 1 was performed except that ultrapure water taken out from the ultrapure water pipe 16 at 200 L / hr using a polytetrafluoroethylene tube having a diameter of 10 mmφ and a length of 1.5 m was directly passed through the specific resistance sensor. The specific resistance was measured, and the measurement results are shown in FIG.
[0046]
FIG. 6 shows that the water quality measuring device of the present invention having the rotating impeller and the straight pipe portion can obtain a measurement result equivalent to the specific resistance sensor provided in the main pipe and has high measurement accuracy. On the other hand, in the comparative example 1, it can be seen that the measurement value of the sensor is unstable due to the pulsation of the water flow, which is greatly different from the measurement result of the specific resistance sensor provided in the main pipe.
[0047]
In Example 1, 0.5 kW of power is generated from the power generator connected to the rotary impeller, while the rated power consumption of the specific resistance sensor used in Example 1 is 0.1 kW. It was confirmed that the necessary power can be sufficiently supplied as the power source of the sensor.
[0048]
Example 2
The water quality measuring device shown in FIG. 4 was attached to the ultrapure water pipe (water supply pressure 0.3 MPa) 16 of the subsystem of the ultrapure water production system shown in FIG. 1, and the specific resistance of the ultrapure water was measured.
[0049]
The sample water pipe 2 is a 10 mmφ polytetrafluoroethylene tube, ultrapure water is taken out from the ultrapure water pipe 16 at 200 L / hr, hydrogen is injected from the hydrogen gas cylinder 8, the rotary impeller 3, deoxygenation catalyst The specific resistance was continuously measured over 18 months by passing water through the packed tower 9, the horizontal straight pipe portion 4 having a length of 5 cm, and the water quality sensor (specific resistance sensor) 5. A commercially available product was used as the hydrogen gas cylinder 8, and the pressure was adjusted to 0.32 MPa with a regulator and injected. As the deoxygenation catalyst packed tower 9, a column made of polytetrafluoroethylene having a diameter of 70 mm and packed with 2.5 L of Pd-supported resin (model number: OC-1063 (manufactured by Bayer)) was used.
[0050]
As the rotary impeller 3, a blade having a diameter of 45 mm, the number of blades of 13 and a blade having a receding angle of 17 ° was used. As a specific resistance sensor, a specific resistance meter “MX-4” manufactured by Kurita Kogyo Co., Ltd. was used.
[0051]
The measurement results of the specific resistance at this time are shown in FIG.
[0052]
Example 3
In Example 2, the specific resistance was measured in the same manner except that the deoxygenation catalyst packed tower was not provided, and the measurement results are shown in FIG.
[0053]
As is clear from FIG. 7, in Example 2, the measured value was stable over 18 months, but in Example 3, the measured value gradually decreased with time, and the sensor measurement was performed under the influence of dissolved oxygen. It can be seen that the accuracy is reduced.
[0054]
In addition, the dissolved oxygen concentration of the ultrapure water of the water to be measured in Example 2 and Example 3 is 20 to 28 μg / L, and the dissolved oxygen concentration after the deoxygenation catalyst treatment in Example 2 is 3 to 5 μg / L. there were.
[0055]
Example 4
The water quality measuring device shown in FIG. 5 was attached to the ultrapure water pipe (water supply pressure 0.3 MPa) 16 of the subsystem of the ultrapure water production system shown in FIG. 1, and the specific resistance of the ultrapure water was measured. However, oxygen gas was blown into the ultrapure water taken out by the sample water pipe 2, and the dissolved oxygen concentration was changed between 1.0 and 3.3 mg-O / L.
[0056]
The sample water pipe 2 is a 10 mmφ polytetrafluoroethylene tube, and ultrapure water is taken out from the ultrapure water pipe 16 at 180 L / hr, and the deaerator 10, the rotary impeller 3, and a horizontal straight line with a length of 0.5 cm are used. The specific resistance was continuously measured over 18 months by passing water through the pipe-like piping part 4 and the water quality sensor (specific resistance sensor) 5. As a degassing membrane of the degassing device 10, “PF-004D” manufactured by Dainippon Ink Co., Ltd. was used. As the rotary impeller 3, a blade having a diameter of 45 mm, the number of blades of 13 and a blade having a receding angle of 17 ° was used. As a specific resistance sensor, a specific resistance meter “MX-4” manufactured by Kurita Kogyo Co., Ltd. was used.
[0057]
The measurement results of the specific resistance at this time are shown in FIG.
[0058]
Example 5
In Example 4, instead of the water quality measurement device shown in FIG. 5, the water quality measurement device shown in FIG. 4 is provided, and after hydrogen is injected from the hydrogen gas cylinder 8 to 1 mg−H ₂ / L, the rotary impeller 3 is installed. Then, the water was passed through the deoxygenation catalyst packed tower 9 and then passed through the 5 cm long horizontal straight pipe section 4 and the specific resistance sensor 5 to measure the specific resistance for 18 months. The results are shown in FIG. . The rotary impeller 3 and the specific resistance sensor used were the same as those in Example 4. As the deoxygenation catalyst packed tower 9, a Pd-supported catalyst (model number: OC-) was used in a 70 mm diameter polytetrafluoroethylene column. 1063 (manufactured by Bayer)) was used.
[0059]
As is clear from FIG. 8, in Example 4 using the deaeration device, the measurement value did not change throughout 18 months, but in Example 5, the measurement value decreased with time. From this result, in the system in which the dissolved oxygen concentration changes, it is possible to stably reduce the dissolved oxygen by using the degassing device, and to prevent the measurement accuracy of the water quality sensor due to dissolved oxygen from decreasing with time. Recognize.
[0060]
【The invention's effect】
As described above in detail, the water quality measuring device of the present invention can easily attach and detach the water quality sensor to / from the main pipe to which water to be measured is transferred, and can stably measure the water quality by the water quality sensor. It can be performed. Moreover, it can be easily operated even in a place where it is difficult to secure a power source. Therefore, the water quality measuring device of the present invention can be easily attached to and detached from an existing water treatment device, and maintenance of the water quality sensor can be easily performed.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of a water quality measuring apparatus of the present invention.
FIG. 2 is a schematic diagram showing a configuration example of a water quality measuring apparatus according to the present invention.
FIG. 3 is a system diagram showing another embodiment of the water quality measuring apparatus of the present invention.
FIG. 4 is a system diagram showing another embodiment of the water quality measuring apparatus of the present invention.
FIG. 5 is a system diagram showing another embodiment of the water quality measuring apparatus of the present invention.
6 is a graph showing specific resistance measurement results in Example 1 and Comparative Example 1. FIG.
7 is a graph showing the measurement results of specific resistance in Examples 2 and 3. FIG.
8 is a graph showing measurement results of specific resistance in Examples 4 and 5. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water quality measuring device 2 Sample water piping 3 Rotating impeller 4 Straight piping part 5 Water quality sensor 6 Power generation device 7 Constant temperature bath 7A Coiled tube 8 Hydrogen gas cylinder 9 Deoxygenation catalyst packed tower 10 Deaeration device 11 Primary pure water tank 12 Pump 13 UV oxidation device 14 Mixed bed type ion exchange device 15 UF membrane separation device 17 Use point

Claims (9)

A sample water pipe connected to a main pipe through which water to be measured for water quality is transferred;
A water quality sensor installed in the sample water pipe;
A rotating impeller provided in a sample water pipe upstream of the water quality sensor;
Possess a straight pipe section having a downstream and at least 5cm length of arranged immediately in front of the water quality sensor of the impeller,
Water measuring device power generator rotational force of the rotating impeller is transmitted is that provided. 2. The water quality measurement according to claim 1, wherein the piping between the water quality sensor and the rotary impeller is provided with rectifying means for rectifying the water flow by causing a pressure loss in the water flow. apparatus. 3. The water quality measuring apparatus according to claim 2, wherein the rectifying means is a filling portion filled with a filler selected from synthetic resin, metal, ceramic particles or mesh, activated carbon, and ion exchange resin .   3. The water quality measuring device according to claim 2, wherein the rectifying means is a U-shaped tube or a coiled tube.   5. The water quality measuring device according to claim 1, wherein a temperature adjusting means is provided upstream of the water quality sensor. 6. The water quality measuring device according to claim 1, wherein electric power generated by the power generation device is used as a drive source for the water quality sensor. The water quality measuring apparatus according to any one of claims 1 to 6 , wherein a dissolved oxygen removing unit is provided in a pipe upstream of the water quality sensor. 8. The water quality measuring apparatus according to claim 7, wherein the dissolved oxygen removing means is a deoxygenation catalyst. 8. The water quality measuring device according to claim 7, wherein the dissolved oxygen removing means is a deaeration device.

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