JP2014115156A - Hazardous substance concentration meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hazardous substance concentration meter which is capable of continuing concentration measurement while preventing an overflow of waste liquid without having to prepare a large waste liquid container even when a maintenance interval is unexpectedly extended.SOLUTION: A hazardous substance concentration meter is provided, which includes: a measurement cell 8 having a measurement electrode 8a which outputs an electrical signal representing concentration of a specific hazardous substance in a liquid; a control unit which switchingly supplies a calibration liquid containing the hazardous substance in known concentration and drinking water containing the hazardous substance in unknown concentration; a concentration computation unit which computes hazardous substance concentration in the drinking water based on the electrical signal generated by the measurement electrode 8a; a waste liquid container 15 for storing waste of the calibration liquid discharged from the measurement cell 8; and a waste liquid level detection unit 15a which detects a waste liquid level of 1 or more in the waste liquid container 15. The control unit switches a supply frequency of the calibration liquid to the measurement cell 8 such that the greater the waste liquid level detected by the waste liquid level detection unit 15a, the less frequently the calibration liquid is supplied.

Description

  The present invention relates to a hazardous substance concentration meter.

  Conventionally, a hazardous substance concentration meter that measures the concentration of harmful substances such as fluorine ions, ammonia ions, chlorine ions, and cyan ions in sample water sampled from factory wastewater or rivers is known (see, for example, Patent Document 1). ).

  In this hazardous substance concentration meter, the measurement electrode is calibrated by supplying the calibration liquid stored in the calibration liquid tank to the measurement cell and measuring the concentration at a predetermined calibration timing. Next, after the calibration liquid is discharged from the measurement cell, the measurement electrode is cleaned by supplying the cleaning water from the cleaning liquid tank to the measurement cell.

JP-A-7-181161

  In a hazardous substance concentration meter that measures the concentration of harmful substances, the calibration solution that calibrates the measurement electrode is also an aqueous solution of harmful substances of known concentration, and the waste liquid of the calibration liquid discharged from the measurement cell after calibration is placed in a predetermined waste liquid container. It needs to be stored. Further, even after the measurement electrode is washed, in order to stabilize the measurement electrode, it is necessary to supply the calibration liquid to the measurement cell, and it is also necessary to store the waste liquid in a predetermined waste liquid container.

  However, if the maintenance interval is lengthened and the calibration operation and the cleaning operation are performed a plurality of times in the meantime, there is a disadvantage that the capacity of the waste liquid container becomes insufficient. In particular, if maintenance is not possible frequently, such as an unattended hazardous substance concentration meter installed in a remote river, install a large waste container so that the waste liquid does not overflow from the waste container when the maintenance interval is extended. There is a problem that it is necessary to prepare the apparatus, and the apparatus becomes large and it becomes difficult to handle the waste liquid container.

  The present invention has been made in view of the above-described circumstances, and does not prepare a large waste liquid container, and continues concentration measurement while preventing overflow of waste liquid even when the maintenance interval is unexpectedly extended. It aims to provide a hazardous substance concentration meter that can

In order to achieve the above object, the present invention provides the following means.
One embodiment of the present invention includes a measurement cell including a measurement electrode that outputs a concentration of a specific harmful substance in a liquid as an electrical signal, a calibration liquid containing the harmful substance at a known concentration, and an unknown concentration in the measurement cell. A control unit that switches and supplies the sample water, a concentration calculation unit that calculates the concentration of the harmful substance in the sample water based on the electrical signal output from the measurement electrode, and the discharge from the measurement cell The waste liquid container that stores the waste liquid of the calibration liquid, and the waste liquid level detection unit that detects one or more levels of the waste liquid in the waste liquid container, wherein the control unit detects the waste liquid detected by the waste liquid level detection unit A toxic substance concentration meter is provided that switches so that the frequency of supplying the calibration solution to the measurement cell is lowered as the level of is increased.

  According to this aspect, the control unit supplies a calibration solution containing a hazardous substance with a known concentration to the measurement cell as necessary or periodically, and stores the electrical signal output by the measurement electrode as a calibration value. Thereafter, the calibration liquid is discharged from the measurement cell to the waste liquid container. Then, the control unit supplies sample water to the measurement cell instead of the calibration solution. At this time, the concentration of the harmful substance in the sample water is calculated by the concentration calculation unit from the electrical signal output from the measurement electrode and the stored calibration value.

  In this case, when the level of the waste liquid of the calibration liquid in the waste liquid container is detected by the waste liquid level detection unit, and the detected level of the waste liquid becomes high, the control unit switches so as to reduce the supply frequency of the calibration liquid to the measurement cell. Thus, the concentration measurement can be continued for a long time while preventing the overflow of the waste liquid even if the maintenance interval is unexpectedly extended without preparing a large waste liquid container.

In the above aspect, the waste liquid level detection unit may detect two or more levels of the waste liquid.
By doing so, the measurement electrode can be calibrated and the concentration measurement with high accuracy can be continued while preventing the overflow of the waste liquid container.

In the above aspect, the control unit may stop supplying the calibration liquid to the measurement cell when the level of the waste liquid detected by the waste liquid level detection unit is higher than the first level. Good.
In this way, the supply of calibration liquid is stopped and the supply frequency of the calibration liquid is made zero, thereby eliminating any further discharge of the calibration liquid to the waste liquid container and preventing overflow more reliably. be able to.

Moreover, in the said aspect, when the level of the said waste liquid detected by the said waste liquid level detection part is higher than a 2nd level, you may provide the alerting | reporting part which alert | reports that.
By doing so, the notification unit notifies the outside that the level of the waste liquid has exceeded the second level, so that the waste liquid container can be properly maintained while continuing the concentration measurement of harmful substances. .

  According to the present invention, there is an effect that concentration measurement can be continued while preventing overflow of waste liquid even when the maintenance interval is unexpectedly extended without preparing a large waste liquid container.

It is a block diagram which shows the harmful substance concentration meter which concerns on one Embodiment of this invention. It is a figure which shows the measurement part main body of the harmful | toxic substance concentration meter of FIG. It is a flowchart which shows the sequence of the harmful substance concentration meter of FIG.

A hazardous substance concentration meter 1 according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the hazardous substance concentration meter 1 according to the present embodiment includes a measurement unit main body 2, a concentration calculation unit 3 that calculates the concentration of harmful substances based on the measurement result by the measurement unit main body 2, A control unit 4 that controls the measurement unit main body 2 and the concentration calculation unit 3, a calibration value storage unit 5 that stores a calibration value, a concentration storage unit 6 that stores the calculated concentration, and an external command according to a command from the control unit 4 And an output unit 7 for outputting data.

  As shown in FIG. 2, the measurement unit main body 2 stores a liquid and measures a specific ion concentration, a calibration cell 9 and 10 that stores a calibration solution, and an adjustment that stores sample water. A tank 11, a cleaning liquid tank 12 for storing a cleaning liquid, an adjusting agent tank 13 for storing an ionic strength adjusting agent, sample water stored in the adjusting tank 11, and an ionic strength adjusting agent stored in the adjusting agent tank 13. Mixing tank 14 to be mixed, waste liquid container 15 for storing the waste liquid discharged from measurement cell 8, piping connecting each part, electromagnetic valves SV <b> 1 to SV <b> 6 for switching the flow path, and liquid in each tank to mixing tank 14. Supplying pumps P1 and P2 are provided. In the figure, reference numerals CV1 and CV2 denote check valves.

The measurement cell 8 includes, for example, a concentration sensor (measurement electrode) 8a that can detect the concentration of cyanide ions as harmful substances. The concentration sensor 8a outputs an electromotive force generated in the ion electrode as a potential difference from the comparison electrode. In the figure, reference numeral 8c denotes a stirrer.
The measurement cell 8 is provided with a temperature control unit 8d at the preceding stage, and the supplied liquid is heated or cooled to adjust the temperature to a constant temperature and then supplied to the measurement cell 8.

  The calibration liquid tanks 9 and 10 include a low calibration liquid tank 9 and a high calibration liquid tank 10 that respectively store two types of calibration liquids having different concentrations. The low calibration liquid tank 9 stores, for example, a calibration liquid containing cyan ions with a concentration of 0.3 ppm, and the high calibration liquid tank 10 stores, for example, a calibration liquid containing cyan ions with a concentration of 3 ppm.

  The adjustment tank 11 includes a sample water intake pipe line 11a for taking sample water from a water source such as a river, and a discharge pipe line 11b for discharging the overflowed sample water to the water source, and stores a certain amount of sample water. ing. The adjustment tank 11 includes a filter 11c that removes dust and the like by allowing sample water to pass therethrough. The adjustment tank 11 is provided with a water supply line (not shown) for supplying clean water for cleaning.

The cleaning liquid tank 12 stores an acidic cleaning liquid, for example, diluted hydrochloric acid.
The adjusting agent tank 13 stores a buffer solution as an ionic strength adjusting agent for adjusting the ionic strength of the sample water.

The mixing tank 14 ionizes cyan contained in the sample water by mixing the sample water and the ionic strength adjusting agent. Reference numeral 14a denotes a stirrer.
The waste liquid container 15 is connected to the measurement cell 8, and mainly stores liquid waste liquid containing the calibration liquid supplied to the measurement cell 8.
Sensors 9a, 10a, 11d, 12a, 13a, 15a for detecting the liquid level of the liquid stored in the calibration liquid tanks 9, 10, the adjustment tank 11, the cleaning liquid tank 12, the adjustment agent tank 13, and the waste liquid container 15, respectively. Is arranged.

  The concentration calculation unit 3 calculates the concentration of cyan ions in the sample water from the calibration potential stored in the calibration value storage unit 5 and the potential output from the concentration sensor 8 a when the sample water is stored in the measurement cell 8. It is supposed to be.

  The calibration value storage unit 5 stores the potentials output from the concentration sensor 8a as two calibration values when two types of calibration solutions are stored in the measurement cell 8, respectively. Specifically, the calibration value storage unit 5 includes the first calibration value detected for the low concentration calibration liquid stored in the low calibration liquid tank 9 and the high concentration stored in the high calibration liquid tank 10. The second calibration value detected for each calibration solution is stored.

  The concentration calculation unit 3 obtains a calibration curve from the first calibration value and the second calibration value stored in the calibration value storage unit 5, and based on the calibration curve, from the potential detected for the sample water, The concentration of cyanide ions in water is calculated.

The density storage unit 6 stores the density calculated by the density calculation unit 3.
Further, the concentration calculated by the concentration calculation unit 3 is output to the outside periodically or as needed via the output unit 7 so that it can be confirmed at a remote terminal.

The control unit 4 controls the solenoid valves SV1 to SV6 and the pumps P1 and P2 according to a predetermined sequence, and performs the concentration measurement process of the sample water, the calibration process of the concentration sensor 8a, and the cleaning process of the concentration sensor 8a. ing.
Specifically, in order to perform the calibration process of the concentration sensor 8a, the controller 4 opens the electromagnetic valves SV4 and SV5, closes the electromagnetic valve SV6, discharges the liquid in the measurement cell 8, and The valves SV4 and SV5 are closed, and the pumps P1 and P2 are operated by switching the solenoid valves SV1 and SV2 so as to open the pipe connecting the calibration liquid tanks 9 and 10 to the mixing tank 14.

  First, the control unit 4 switches the solenoid valves SV1 and SV2 to operate the pumps P1 and P2. Thereby, first, the low concentration calibration solution from the low calibration solution tank 9 and the buffer solution stored in the regulator tank 13 are supplied to the mixing tank 14 and mixed by the stirrer 14a. Then, the uniformly mixed calibration solution and buffer solution are adjusted to a constant temperature via the temperature control unit 8 d and supplied to the measurement cell 8. And the control part 4 memorize | stores the electric potential output from the density | concentration sensor 8a in the calibration value memory | storage part 5 as a low calibration 1st calibration value. After the first calibration value is stored, the control unit 4 opens the electromagnetic valves SV4 and SV6, discharges the entire amount of the calibration liquid in the measurement cell 8 to the waste liquid container 15, and closes the electromagnetic valve SV4.

  Next, the control unit 4 switches the electromagnetic valve SV2. As a result, the high-concentration calibration liquid from the high calibration liquid tank 10 and the buffer liquid stored in the adjusting agent tank 13 are supplied to the mixing tank 14, mixed by the stirrer 14a, and uniformly mixed. And the buffer solution are adjusted to a constant temperature via the temperature control unit 8 d and supplied to the measurement cell 8. And the control part 4 memorize | stores the electric potential output from the density | concentration sensor 8a in the calibration value memory | storage part 5 as a 2nd high calibration value. Even after the second calibration value is stored, the control unit 4 opens the electromagnetic valves SV4 and SV6, discharges the entire amount of the calibration liquid in the measurement cell 8 to the waste liquid container 15, and closes the electromagnetic valve SV4.

  Further, in order to perform the sample water concentration measurement process, the control unit 4 switches the solenoid valves SV1 and SV3 and operates the pumps P1 and P2 so as to open the pipe connecting the adjustment tank 11 to the mixing tank 14. Let Thereby, the sample water stored in the adjusting tank 11 and the buffer solution stored in the adjusting agent tank 13 are supplied to the mixing tank 14 and mixed by the stirrer 14a. Then, the uniformly mixed sample water and buffer solution are adjusted to a constant temperature via the temperature control unit 8d, and supplied to the measurement cell 8 to perform concentration measurement.

  The control unit 4 sends the potential output from the concentration sensor 8a and the two calibration values stored in the calibration value storage unit 5 to the concentration calculation unit 3 to calculate the cyan ion concentration. The control unit 4 stores the concentration calculated by the concentration calculation unit 3 in the concentration storage unit 6 and outputs it to the outside via the output unit 7.

  In order to perform the cleaning process of the concentration sensor 8a, the control unit 4 opens the electromagnetic valves SV4 and SV5, closes the electromagnetic valve SV6, and supplies the sample water in the measurement cell 8 to the outside (for example, a water source). After discharging to a river or the like, the solenoid valve SV4 is closed, and the solenoid valves SV1 and SV3 are switched so that the pipe connecting the cleaning liquid tank 12 to the mixing tank 14 is opened, and the pump P1 is operated. As a result, the cleaning liquid is supplied to the measurement cell 8, and the concentration sensor 8a is cleaned.

  Further, since the concentration sensor 8a becomes unstable after the concentration sensor 8a is cleaned with the cleaning liquid, the control unit 4 always calibrates the low calibration liquid tank 9, for example, at a low concentration after the concentration sensor 8a is cleaned. A restoration process for supplying the liquid to the measurement cell 8 is performed, and the calibration liquid after the restoration process is discharged to the waste liquid container 15.

  Further, the control unit 4 monitors signals from the sensors 9a, 10a, 11d, 12a, and 13a provided in the respective tanks, and the first calibration solution, the second calibration solution, the sample water, the cleaning solution, and the buffer solution. When it is detected that each of the above has become insufficient, the fact is notified to the outside via the output unit 7 to encourage replenishment.

Furthermore, in the hazardous substance concentration meter 1 according to the present embodiment, the control unit 4 monitors the signal from the sensor (waste liquid level detection unit) 15a provided in the waste liquid container 15 and switches the sequence of each process. It has become.
That is, in this embodiment, the sensor 15a provided in the waste liquid container 15 detects that the volume of the liquid containing the calibration liquid discharged to the waste liquid container 15 has reached a predetermined level. .

When the detection signal from the sensor 15a is input, the control unit 4 notifies the outside via the output unit 7 and skips the calibration process of the concentration sensor 8a and the cleaning process of the concentration sensor 8a. It is like that.
That is, as shown in FIG. 3, when the sequence is started, the control unit 4 first checks whether or not the output (FS6) of the sensor 15a provided in the waste liquid container 15 is ON (step S4). S1) If the threshold value is exceeded, this is notified to the outside via the output unit 7 (step S2), and the calibration process of the density sensor 8a is skipped to perform the density measurement process (step S8). .

  On the other hand, if the level of the waste liquid container 15 does not exceed the threshold value, it is determined whether or not the calibration process of the concentration sensor 8a is necessary (step S3). When the calibration process of the density sensor 8a is necessary, the calibration process is performed (steps S4 and S6), the calibration value is stored (steps S5 and S7), and when the calibration process is not necessary, the calibration process is skipped. Then, density measurement processing is performed (step S8), and the density is stored (step S9).

  Next, the control unit 4 determines whether or not the concentration sensor 8a needs to be cleaned (step S10), and if necessary, checks the output FS6 of the sensor 15a provided in the waste liquid container 15. (Step S11) If the threshold is not exceeded, a cleaning process (Step S12) and a return process are performed (Step S13). When the cleaning process is not necessary, when the output of the sensor 15a exceeds the threshold value, and when the return process is completed, the process from step S1 is repeated.

  Here, the determination of whether or not the calibration process of the concentration sensor 8a is necessary and the determination of whether or not the cleaning process is necessary may be performed according to the elapsed time, for example, as disclosed in Japanese Patent No. 3382334. As described, fuzzy diagnosis may be performed for determination.

  As described above, according to the hazardous substance concentration meter 1 according to the present embodiment, the concentration sensor 8a is calibrated when the sensor 15a provided in the waste liquid container 15 detects that the waste liquid exceeds a predetermined level. Continuing the concentration measurement while preventing the overflow of the waste liquid until the arrival of the maintenance worker who received the notification from the output unit 7 because the generation of the further waste liquid is prevented by skipping the processing and the cleaning process There is an advantage that can be.

  That is, even in an environment where maintenance cannot be performed in a timely manner, such as when installed in a remote river, the overflow of waste liquid can be prevented without stopping concentration measurement. . As a result, it is not necessary to prepare a waste liquid container 15 having a large capacity, and there is an advantage that the toxic substance concentration meter 1 can be downsized and the workability of the replacement work of the waste liquid container 15 can be improved.

  In the present embodiment, the sensor 15a provided in the waste liquid container 15 detects whether or not the waste liquid has reached a single predetermined level so as not to overflow, but instead, A plurality of levels may be detected. In this case, as described above, when the highest level is detected, the calibration process and cleaning process of the concentration sensor 8a are skipped, and when a level lower than that is detected, the calibration process of the concentration sensor 8a and The frequency of the cleaning process may be adjusted.

  That is, by adjusting the concentration sensor 8a so that the frequency of the calibration process and / or the cleaning process decreases as the level of the waste liquid increases, the rate of increase in the level of the waste liquid in the waste liquid container 15 is decreased. There is an advantage that the concentration measurement can be continued while calibrating or cleaning the concentration sensor 8a for a longer period of time.

  Further, in the present embodiment, when the liquid level of the waste liquid detected by the sensor 15a provided in the waste liquid container 15 exceeds the predetermined threshold, this is notified, but a plurality of thresholds are provided, You may decide to perform alerting | reporting with high urgency as the level of a waste liquid becomes high. For example, when alerting by sound, the level of urgency is increased by increasing the volume or increasing the pitch, and when displaying on the screen or with light, it is turned red or blinked. And increase the level of urgency.

  In the present embodiment, the case of measuring the concentration of cyanide ions in the sample water has been described as an example, but instead of this, the concentration of other harmful substances such as fluorine ions, ammonia ions, and chlorine ions is measured. You may apply.

DESCRIPTION OF SYMBOLS 1 Toxic substance concentration meter 3 Concentration calculation part 4 Control part 7 Output part (notification part)
8 Measurement cell 8a Concentration sensor (measuring electrode)
15 Waste liquid container 15a Sensor (Waste liquid level detector)

Claims (4)

A measurement cell having a measurement electrode for outputting the concentration of a specific harmful substance in the liquid as an electrical signal;
A controller for switching and supplying a calibration solution containing the harmful substance with a known concentration and a sample water with an unknown concentration to the measurement cell;
A concentration calculator that calculates the concentration of the harmful substance in the sample water based on the electrical signal output from the measurement electrode;
A waste liquid container for storing a waste liquid of the calibration liquid discharged from the measurement cell;
A waste liquid level detection unit for detecting one or more levels of the waste liquid in the waste liquid container;
A hazardous substance concentration meter in which the control unit switches so that the frequency of supplying the calibration solution to the measurement cell decreases as the level of the waste solution detected by the waste solution level detection unit increases.   The hazardous substance concentration meter according to claim 1, wherein the waste liquid level detection unit detects two or more levels of the waste liquid.   The said control part stops supply of the said calibration liquid to the said measurement cell, when the level of the said waste liquid detected by the said waste liquid level detection part is higher than a 1st level. Noxious substance concentration meter.   The hazardous substance concentration according to any one of claims 1 to 3, further comprising a notification unit that notifies the outside when the level of the waste liquid detected by the waste liquid level detection unit is higher than a second level. Total.

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