Water quality measuring device and water quality measuring method

Abstract

To provide a water quality measuring device and a method for measuring water quality which can easily detect dirt on a water quality sensor and can properly clean the water quality sensor.SOLUTION: A water quality measuring device having a water quality sensor 1 with a sensor body 2 in contact with measurement target water includes: fluid spraying means having a nozzle 5 for spraying a fluid to a sensor body 2; and an operation control unit 4 for determining the degree of dirt on the sensor body on the basis of the change of an output signal of the sensor body 2 after the fluid spraying means sprays fluid to the sensor body. A method for measuring water quality using the water quality measuring device is also disclosed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water quality measurement apparatus and a water quality measurement method using a water quality sensor such as a pH meter or a conductivity meter.

Background Art

[0002] When continuously measuring water quality using a water quality sensor such as a pH meter, suspended substances, microorganisms, iron hydroxide, iron oxide, etc. in water adhere to the surface of the water quality sensor such as the pH electrode, and the measurement accuracy and responsiveness gradually decrease.

[0003] Detecting the contamination of the electrode part of the pH meter and cleaning the pH meter based on the detection result are described in Patent Document 1. Patent Document 1 obtains the time from the start time of chemical solution cleaning to the time when the pH measurement value or detection value becomes a predetermined value as an evaluation time, and based on the evaluation time, generates adjustment information for adjusting one or both of the cleaning cycle and cleaning time for cleaning the pH electrode with the chemical solution. It is a pH measurement system configured as follows.

[0004] Patent Document 2 describes that as a cleaning method for a pH meter, when the pH sensitivity decreases, the pH meter is cleaned with a chemical solution.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In normal use, the pH meter is sufficient with only physical cleaning, and chemical solution cleaning is basically performed when dirt accumulates. Therefore, the method of Patent Document 1 cannot sufficiently grasp the dirt situation.

[0007] The method described in Patent Document 2 cannot determine contamination until it has progressed to a certain extent. Chemical cleaning, on the other hand, can detect contamination at an early stage. of It is effective to implement this in certain situations, and there was a need for a method to detect contamination early.

[0008] The present invention aims to provide a water quality measuring device and a water quality measuring method that can easily detect contamination of a water quality sensor and properly clean the water quality sensor. [Means for solving the problem]

[0009] The water quality measuring device of the present invention is a water quality measuring device equipped with a water quality sensor having a sensor body that comes into contact with the water to be measured, and comprises a fluid spraying means having a nozzle for spraying fluid toward the sensor body, and a determination means for determining the degree of contamination of the sensor body based on the change in the output signal of the sensor body after the fluid has been sprayed by the fluid spraying means.

[0010] In one embodiment of the water quality measuring device of the present invention, the sensor body is rod-shaped, a sensing unit is provided at its tip, and the nozzle is arranged to spray the fluid onto the sensing unit.

[0011] In one embodiment of the water quality measuring device of the present invention, the sensor is a pH meter.

[0012] The water quality measurement method of the present invention is a water quality measurement method using the water quality measuring device of the present invention, comprising the steps of spraying fluid onto the sensor body with the fluid spraying means and cleaning the sensor body based on the subsequent change in the output signal of the sensor body. [Effects of the Invention]

[0013] According to the present invention, contamination of a water quality sensor can be easily detected, and the water quality sensor can be properly cleaned. [Brief explanation of the drawing]

[0014] [Figure 1] It is a configuration diagram of a water quality measuring device according to an embodiment. [Figure 2] It is a signal change diagram in an embodiment.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments will be described with reference to FIG. 1.

[0016] As shown in FIG. 1, a sensor 1 composed of a pH meter or a conductivity meter has a rod-shaped sensor body (probe in this embodiment) 2 in contact with the water to be measured and a sensor base 3 to which the base end side of the sensor body 1a is connected. The detection signal of the sensor 1 is input to the arithmetic controller 4.

[0017] The tip of the sensor body 2 serves as a sensing portion. A nozzle 5 is installed so as to spray fluid toward the tip of the sensor body 2. In this embodiment, a liquid is used as the fluid, and the liquid in the tank 6 can be supplied to the nozzle 5 via a pump 7 and a tube 8. The pump 7 is controlled to be ON or OFF by a control signal from the arithmetic controller 4.

[0018] When the sensor 1 is a pH meter, air, clean water, or an aqueous solution with a known pH (for example, a buffer) is suitable as the fluid.

[0019] This sensor 1 measures the potential difference induced on the surface of the probe 2 (glass tube) by a reference electrode and a working electrode, which are not shown in the figure, in the same manner as a general pH electrode, and sends it to the arithmetic controller 4 to measure the pH value.

[0020] When detecting the contamination of the probe 2, the arithmetic controller 4 operates the pump 7 for a predetermined time and sprays fluid from the nozzle 5 to the tip of the probe 2 for a predetermined time T (for example, 0.1 to 10 seconds, particularly 1 to 5 seconds).

[0021] As a result, the detected pH, which is the output signal of sensor 1, starts hunting with a delay of a predetermined time t1 from the start of spraying, as shown in Fig. 2.

[0022] Measure the hunting width a1 during a specified time (for example, 10 - 80% of the above-mentioned predetermined time T) from the start of this hunting. Then, based on t1 and a1, determine the degree of contamination at the tip of probe 2.

[0023] Specifically, it is determined that the degree of contamination is greater as t1 is larger and a1 is smaller. For example, calculate the contamination index P = mt1 + n(1 / a1) (where m and n are constants determined experimentally), and if P exceeds the reference value, clean probe 2.

[0024] At this time, it is preferable to increase the cleaning intensity as the P value increases. For example, increase the cleaning time or perform cleaning using a cleaning chemical.

[0025] In this way, the contamination of sensor 1 (probe 2) can be accurately detected, and sensor cleaning can be appropriately performed.

[0026] The arithmetic controller 4 includes an arithmetic output unit that calculates and outputs measurement output data based on the measurement signal, a pump control unit that controls pump 7, etc. The arithmetic controller includes a microprocessor and performs a series of operations according to a program.

[0027] As the clean water, tap water, distilled water, deionized water, pure water, ultrapure water, etc. can be used, but it is not limited thereto.

[0028] As the cleaning chemical solution, those having the property of removing the deposits on probe 2 are used. When the deposits mainly consist of iron hydroxide or iron oxide, an acid aqueous solution such as hydrochloric acid (for example, 9% hydrochloric acid) is suitable as the chemical solution, but it is not limited thereto.

[0029] The above-mentioned fluid may be air. In this case, compressed air is ejected from nozzle 5 by a compressor, blower, air cylinder, etc.

[0030] In this embodiment, sensor 1 is a standard pH meter, but it may also be a conductivity meter or the like.

[0031] The water quality measuring device of the present invention can be suitably used in various wastewater treatment facilities such as coagulation reaction tanks and pure water production equipment, but it can also be used for other applications.

[0032] The above embodiments are examples of the present invention, and the present invention is not limited to these embodiments. The present invention can also be applied to water quality measurements other than pH and electrical conductivity. [Explanation of Symbols]

[0033] 1 sensor 4. Arithmetic Controller 5 nozzles 6 tanks 7 Pumps 8 tubes

Claims

1. In a water quality measuring device equipped with a water quality sensor having a sensor body that comes into contact with the water to be measured, A fluid spraying means having a nozzle for spraying fluid toward the sensing part of the sensor body, Control means for the fluid spraying means, A determination means for determining the degree of contamination of the sensor body based on the change in the output signal of the sensor body after the fluid has been sprayed by the fluid spraying means. A water quality measuring device comprising: The fluid spraying means sprays fluid onto the sensing unit for a predetermined time T. The determination means measures the elapsed time t1 from the start of spraying until the start of hunting in the output signal of the sensor body, and the hunting width a1 of the output signal during 10 to 80% of the predetermined time T after the elapsed time t1, and determines the degree of contamination of the sensor body based on the measured t1 and a1. Water quality measuring device.

2. The determination means determines the dirt index P P = mt 1 + n(1 / a 1) (where m and n are predetermined constants) The water quality measuring device according to claim 1, which calculates the degree of pollution based on this P value.

3. The water quality measuring device according to claim 1, wherein the sensor is a pH meter and the fluid is air, clean water, or a buffer.

4. A method for measuring water quality using the water quality measuring device described in any one of claims 1 to 3.

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