JPH09292329A - Turbidimeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the frequency of cleanings inside cells and to decrease the load of maintenance control by using a plurality of sample cells as the cells for high- concentration samples and the cells for low-concentration samples. SOLUTION: An iron-concentration monitor is constituted by combining a first turbidity detecting part and a second turbidity detecting part B, having an identical structure. At the time of the continuous measurement of water quality in clean-up at the starting time after the disassembled cleaning in a steam turbine, e.g. high- concentration sample liquid is supplied into a cell 6 of the turbidity detecting part A from a water supply port 7, and monitoring is performed. When after starting, the iron concentration becomes low by the elapse of time and the measured result of an amplifier operator 13 becomes the turbidity of switching target of the high- concentration monitor and the low-concentration monitor preset beforehand, the detecting part is changed to the turbidity detector B by a switching device 16. Low- concentration sample liquid is supplied into the cell 6' of the turbidity detector B, and the low-concentration monitoring at the time of the so-called ordinary operation is performed. Thus, the number of times of the cleanings inside the cells 6 and 6' can be decreased, and the cell 6 used for the high-concentration monitoring can be cleansed during the low-concentration monitoring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbidimeter, and more particularly to a turbidimeter for optically determining turbidity by a scattered light / transmitted light ratio.

[0002]

2. Description of the Related Art A turbidity measuring method for optically obtaining turbidity is as follows.
Widely used as an integral part of water quality management in the electronics industry, pharmaceuticals, food, and cosmetics, as well as water quality management for thermal power plants and nuclear power plants.Used especially for iron concentration monitors that measure the concentration of iron in service water. Have been.

FIG. 3 shows a block diagram of an iron concentration monitor used in a thermal power plant, etc. This method is an optical turbidity measuring method of scattered light / transmitted light ratio in accordance with JISK0101 for industrial water test method. It is based on.

In FIG. 3, 1 is a light source, 2 is a condenser lens, 3 is a pinhole, 4 is a collimator lens, 5 is a filter, 6 is a sample measuring cell provided with a water supply port 7 and a drainage port 8, Reference numeral 9 is a condenser lens, 10 is a transmitted light detector, 11 and 12 are scattered light detectors, 13 is an amplifier of the detected values by the transmitted light detector 10 and the scattered light detectors 11 and 12, a calculator, and 14 is a display meter. , 15 are glass windows installed at the boundary so that the sample liquid in the cell 6 does not leak to the optical system.

In the iron concentration monitor having such a configuration, light from the light source 1 is converted into a parallel light flux by an optical system including a condenser lens 2, a pinhole 3, a collimator lens 4, and a filter 5, and is guided into a cell 6. In the cell 6, for example, a sample solution containing colloidal iron is supplied with a water supply port 7.
And flows out from the drain 8.

When the light beam is irradiated on the sample liquid in the cell 6, the light is separated into light transmitted and scattered by the iron particles (particle diameter: 0.1 to 10 μm) suspended in the liquid, and each of the transmitted light detectors is used. 10 and the scattered light detectors 11 and 12 are input to the amplifier and the arithmetic unit 13 as photoelectric signals. Amplifier, arithmetic unit 1
In 3, calculate the ratio of scattered light / transmitted light and calculate iron concentration (turbidity)
Is displayed on the display meter 14.

The calculation of the density is as follows:

[0008]

T = Ts / (nTs + Tt) where T is turbidity, Ts is the intensity of scattered light, Tt is the intensity of transmitted light, and n is a coefficient.

[0009]

To convert the measured turbidity value into iron concentration,
A parameter obtained by performing regression analysis of the turbidity value and the iron concentration by the TP-TZ method is used as a conversion coefficient. It has been experimentally confirmed that the correlation between the measured value of the iron concentration monitor and the manual analysis value by the TP-TZ method has a correlation coefficient of 0.9 or more.

The TP-TZ method, which is a colorimetric analysis method for measuring the absorbance of a blue color developed by a reaction between a TP-TZ reagent and iron ions, as specified in JIS, is a colorimetric method. Pre-processing takes time, and measurement is also done offline, which is also time-consuming. Further, since a reagent is used, adjustment and replenishment of the reagent are required, which makes the handling complicated and expensive.

On the other hand, the iron concentration measuring method by the turbidity measuring method solves the problem of the TP-TZ method.
By first correlating the turbidity value with the manual analysis value by the TP-TZ method, the iron concentration can be continuously measured and displayed online, so that it is possible to control the tendency of cleaning water during cleanup at power plants, etc. , Is an effective means for continuous management.

[0013]

The generator of a thermal power plant undergoes a periodic inspection once a year. After disassembly and cleaning in the steam turbine, water cleaning is performed. At that time, continuous measurement of cleanup water quality at startup using an iron concentration monitor is performed, and then water quality monitoring during normal operation is continued. That is, from the use as a high concentration monitor (2000 ppb or more) at the time of cleanup, to the low concentration monitor (several ppb or less) during normal operation.
Since the cell is contaminated during operation as a high-concentration monitor because it is used consistently until the use as a
Intracellular washing is required once every three weeks. When cleaning the inside of the cell, it is necessary to perform span adjustment for each measurement point after cleaning, which is a burden on maintenance management.

The present invention reduces the number of times of in-cell cleaning of a turbidimeter used as a high concentration monitor and a low concentration monitor,
The purpose is to reduce the burden of maintenance management.

[0015]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above problems, has the following constitution.

(1) A sample liquid cell in which a sample liquid in which fine particles are suspended is continuously fed is irradiated with a light beam, and the turbidity of the sample liquid is determined from the ratio of transmitted light or scattered light to incident light. In a turbidimeter for determining the above, a structure having at least two cells for the sample solution, and a part of the cells for the sample solution can be switched as a high-concentration sample cell and a part as a low-concentration sample cell It is characterized by becoming.

(2) In (1), there is one cell for the high-concentration sample and one cell for the low-concentration sample, and the sample solution is supplied to the cell at a preset turbidity. Means for switching the measurement by the cell for the high-concentration sample to the measurement by the cell for the low-concentration sample, switching the irradiation of the light flux to the sample solution, the supply of power to the detector of the transmitted light, the scattered light, etc. It is characterized by having.

(3) In (1) or (2), the light source of the cell for the high concentration sample and the light source of the cell for the low concentration sample consist of a single light source.

(4) In (1), (2) or (3), the turbidimeter is an iron concentration monitor for measuring the concentration of iron contained in the water.

[0020]

FIG. 1 is an explanatory view showing the structure of an iron concentration monitor in an embodiment of a turbidimeter of the present invention. The iron concentration monitor has a first turbidity detection section A and a second turbidity detection unit which have the same structure. It is configured by combining two systems of the turbidity detection unit B.
The same parts as those of
Parts of the turbidity detection unit B are marked with a dash ('). Reference numeral 16 denotes a switch between the first turbidity detecting section A and the second turbidity detecting section B.

In this iron concentration monitor, for example, the first turbidity detector A is used as a high concentration monitor and the second turbidity detector B is used as a low concentration monitor.

After disassembling and cleaning the inside of the steam turbine, at the time of continuous water quality measurement at start-up, a high-concentration sample liquid is supplied from the water supply port 7 into the cell 6 of the first turbidity detection unit A. , Discharged from the drainage port 8. The first turbidity detector A acts as a so-called high-concentration monitor. In this case, the light from the light source 1 passes through the condenser lens 2, the pinhole 3, the collimator lens 4, the filter 5 and the glass window 15, and the cell. Enter 6. The light irradiated on the iron fine particles in the sample solution in the cell 6 is divided into scattered light and transmitted light, and the transmitted light detector 1
0, the scattered light detectors 11 and 12 are input, and are input to the amplifier and the calculator 13 as photoelectric signals.

After a lapse of time from the time of start-up, the sample solution having a low iron concentration is switched from the first turbidity detecting section A to the second turbidity detecting section B for measurement. The measurement by the second turbidity detection unit B is performed in exactly the same manner as the first turbidity detection unit A.

First turbidity detecting section A and second turbidity detecting section B
Is switched by the switch 16 and displayed on the display meter 14. The switch 16 has a function of monitoring the concentration of the cell 6 of the first turbidity detection unit A and comparing it with a preset concentration, and the output signal thereof is used for switching. Further, the system of the sample liquid in the first turbidity detecting section A and the second turbidity detecting section B is also switched by the same signal.

Therefore, when operating as a high-concentration monitor, the measurement result of the amplifier and the arithmetic unit 13 for the switching device 16 and the turbidity of the switching target of the high-concentration monitor and the low-concentration monitor set in advance are set. When this happens, the supply and discharge of the sample solution to the high-concentration monitor side is stopped, the power supply to the transmitted light detector 10 and the scattered light detectors 11 and 12 is stopped, and the sample solution to the low-concentration monitor side is stopped. Supply and discharge of
By supplying power to the transmitted light detector 10 and the scattered light detectors 11 and 12, switching between the high concentration monitor and the low concentration monitor can be automated.

FIG. 4 is a diagram showing the relationship between the density of scattered light and the light output voltage. The horizontal axis and the vertical axis respectively represent the density (pp
b), the optical output voltage (mV) is taken, and FIG. 5 is a relationship diagram of the cleanup time and the concentration. The horizontal axis and the vertical axis show the time (hr) and the concentration (ppb), respectively. . From the relationship between FIG. 4 and FIG. 5, it is possible to determine the timing of switching between the first turbidity detection unit A and the second turbidity detection unit B. In the iron concentration monitor in this embodiment, the cells were switched at 20 ppb after 4 hours. That is, the high-concentration sample solution is measured in the cell 6 for 4 hours, the water inlet 7 (solenoid valve) is closed, and the water inlet 7 '(solenoid valve) of the cell 2'is opened to continue the measurement as a low concentration monitor. With such a structure, the problem that the performance is not maintained for low-concentration measurement due to little stains over time has been solved.

Since the conventional iron concentration monitor has only one cell and is used for measuring a liquid having a high concentration to a low concentration, the cell must be washed every 2-3 weeks. . In the iron concentration monitor of this embodiment, since the cell has a structure having, for example, two cells, the one used as the high concentration cell and the one used as the low concentration cell are divided and used by switching. It has become possible to extend the period of use of the low-concentration monitor, and the cell can be cleaned once every 3 to 6 months. That is, it is possible to reduce the number of washings in the cell, and it is possible to switch automatically at a preset concentration, and the cell used as a high-concentration monitor performs washing work during measurement by the low-concentration monitor. Therefore, continuous measurement is possible.

FIG. 2 shows an iron concentration monitor according to another embodiment of the present invention. In the iron concentration monitor of FIG. 1, the light source for the high concentration monitor and the light source for the low concentration monitor can be operated by one light source. Therefore, the light sources 1 and 1 ′ can be switched by the light source position changer 17 (the light sources 1 and 1 ′ in FIG. 2 show a state in which the positions of the same light source are changed), and the supply of the sample solution by the switch 16 The light source position varying device 17 can be switched when the ports 7, 7 ', the outlets 8, 8'are opened and closed, and the amplifiers and the arithmetic units 13 and 13' are switched.

The iron concentration monitor having such a structure operates in the same manner as the iron concentration monitor of FIG. 1 and can obtain the same effect. Further, since only one light source is required, the influence of variations in the light source can be eliminated. You can

[0030]

INDUSTRIAL APPLICABILITY The present invention reduces the number of times of washing in a turbidimeter used as a high-concentration monitor and a low-concentration monitor in a cell, and can reduce the burden of maintenance management. It is great.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an iron concentration monitor according to an embodiment of a turbidimeter of the present invention.

FIG. 2 is an explanatory diagram of another iron concentration monitor.

FIG. 3 is a schematic configuration diagram of a conventionally used iron concentration monitor.

FIG. 4 is a relationship diagram of concentration and optical output voltage for explaining the principle of the present invention.

FIG. 5 is a relationship diagram of cleanup time and concentration for explaining the principle of the present invention.

[Explanation of symbols]

A ... 1st turbidity detection part, B ... 2nd turbidity detection part, 1,
1 '... light source, 2 2' ... condenser lens 3, 3 '...
Pinholes 4, 4 '... Collimator lenses 5, 5' ...
Filter, 6, 6 '... Cell, 7, 7' ... Water inlet, 8,
8 '... Drainage port, 9, 9' ... Condensing lens 10, 10 '
... Transmitted light detector, 11, 11 ', 12, 12' ... Scattered light detector, 13, 13 '... Amplifier, calculator, 14 ... Display meter, 15, 15' ... Glass window, 16 ... Switching device, 17 …
Light source position variable device.

Claims (4)

[Claims] 1. A turbidity of the sample solution is determined from the ratio of transmitted light or scattered light to incident light by irradiating a light beam to a sample solution cell to which a sample solution in which fine particles are suspended is continuously fed. The turbidimeter to be obtained has at least two cells for the sample solution, and has a structure in which some of the cells for the sample solution can be switched as cells for high-concentration sample and some as cells for low-concentration sample. Turbidimeter characterized by 2. The cell for the high-concentration sample and the cell for the low-concentration sample are each one, and the sample solution is supplied to the cell and the sample solution is supplied to the cell at a preset turbidity. The means for switching the measurement by the cell for the high-concentration sample to the measurement by the cell for the low-concentration sample, which switches the irradiation of the light flux, the supply of power to the detector of the transmitted light, the scattered light, and the like. Turbidimeter described. 3. The turbidimeter according to claim 1, wherein the light source of the high concentration sample cell and the light source of the low concentration sample cell are a single light source. 4. The turbidimeter according to claim 1, 2 or 3, wherein the turbidimeter is an iron concentration monitor that measures the concentration of iron contained in the water.