JP2010038708A - Metal concentration monitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal concentration monitor capable of outputting a turbidness occurrence without large load to the monitor even under measurement environment where sudden turbidness is observed in waste water. <P>SOLUTION: The monitor includes a sampling control section 31 sampling periodically a sample liquid and supplying it to a reservoir; a turbidness sensor 18 detecting a turbidity of the sample liquid in the reservoir; a turbidness condition announcing section 32 outputting an occurrence of turbidness condition when the turbidity of the sample liquid in the reservoir exceeds a threshold; a sample liquid exchange control section 33 discarding the sample liquid with the turbidity exceeding the threshold from the reservoir, sampling newly a sample liquid, and supplying it to the reservoir; and a sample injection control section 34 injecting a part of the sample liquid into a furnace of a furnace atomic absorption spectrometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a metal concentration monitoring device for periodically measuring a metal substance contained in a liquid such as factory effluent and monitoring the concentration in the liquid, and more specifically, a measuring device for a metal substance etc. in the liquid. The present invention relates to a metal concentration monitoring apparatus using a furnace atomic absorption spectrophotometer.
In addition, the term “metal substance” as used herein includes, in addition to the original metal substance, an element that may be contained in industrial waste water such as cadmium and arsenic and that can be measured by atomic absorption spectrometry. Shall.

In water quality management such as factory effluent, drainage is collected periodically after a certain period of time, and various metal concentrations such as lead, cadmium, chromium and arsenic contained in the liquid are measured, and preset control values are set. A metal concentration monitoring device (metal in-line monitor) is used to warn by issuing an output signal to that effect when exceeding.
In general, measurement instruments that can measure the metal concentration in the liquid include inductively coupled radio frequency plasma mass spectrometer (ICP-MS), inductively coupled radio frequency plasma emission spectrometer (ICP-MS), depending on the substance to be measured and measurement conditions ( ICP-OES) and atomic absorption spectrophotometer (AAS) are used (see Patent Documents 1 and 2).

An atomic absorption spectrophotometer, which is one of these measuring instruments, can detect many types of metals in a short time, and is therefore suitable as a measuring instrument for managing the quality of wastewater containing various metals. On the other hand, in the measurement for the purpose of water quality management, since the measurement is repeated continuously for a long time regardless of day or night, unattended monitoring is fundamental. For this reason, we do not want to use measuring instruments that use frames (flames) for safety reasons.
Therefore, when an atomic absorption spectrophotometer is used, a furnace atomic absorption spectrophotometer that does not use a frame is used instead of a flame atomic absorption spectrophotometer.

The measurement of a metal substance by a furnace atomic absorption spectrophotometer is an analysis method capable of measuring a ppb level with a very small amount of sample (about several tens of μL). On the other hand, the management concentration of the metal in the wastewater is usually at the ppm level. Therefore, when measuring with a furnace atomic absorption spectrophotometer for a metal concentration monitoring device (in-line monitor), the measurement sensitivity of the device is too high compared to the control concentration, so the measurement sensitivity is intentionally lowered to perform the measurement. Specifically, the measurement wavelength for the metal material is removed from the most suitable wavelength, and the sensitivity is lowered to perform the measurement.
JP 2006-284374 A Japanese Patent Laid-Open No. 06-337264

By the way, in the in-line measurement that collects factory wastewater etc. repeatedly every predetermined time and continuously checks for abnormalities, not the one-time measurement (batch measurement), pay attention to the state change of the collected wastewater (sample liquid) Cost.
That is, the drainage to be collected is not necessarily in a constant state, and the drainage may be turbid for some reason. In the in-line measurement, pretreatment such as filtration and decomposition is not performed even if the wastewater is cloudy. Therefore, if turbidity occurs, the reliability of the analysis value is impaired due to the influence. Also, depending on the causative substance of turbidity, there is a possibility that the apparatus may be adversely affected.

  Therefore, the present invention prevents the apparatus from being subjected to a great load even in a measurement environment where sudden turbidity is observed in the drainage, and yet can output that turbidity has occurred. An object is to provide a concentration monitoring device.

  In order to solve the above-described problems, the present invention outputs that the turbidity is generated in the sample without performing the measurement with the turbid sample liquid when the sample liquid is turbid. Measures are taken after taking measures to avoid turbidity and suppressing adverse effects on the device due to turbidity.

  That is, the metal concentration monitoring device of the present invention measures the concentration of metal contained in the sample liquid by injecting a part of the collected sample liquid into the furnace of the furnace atomic absorption photometer by the sample injection mechanism and performing atomic absorption measurement. A metal concentration monitoring device that collects a sample solution at predetermined time intervals and supplies the sample solution to a reservoir, a turbidity sensor that detects the turbidity of the sample solution in the reservoir, and a sample solution in the reservoir A turbidity state notification unit that outputs the occurrence of a turbid state when the turbidity exceeds a threshold value, and a sample that discards the sample liquid whose turbidity exceeds the threshold value from the reservoir and newly collects the sample liquid and supplies it to the reservoir A liquid exchange control unit, and a sample injection control unit that injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold value It is.

Here, the “predetermined time interval” is a time interval when repeatedly measuring with a furnace atomic absorption spectrophotometer, and means a preset time interval. If this time interval is shortened, the measurement frequency increases. Specifically, it is set at intervals of several minutes to several hours.
In addition, as described above, “metal” whose concentration is measured by a furnace atomic absorption spectrophotometer is an element that may be contained in factory effluents such as cadmium and arsenic together with the original metal element. Also included are elements that can be measured by atomic absorption.
The “turbidity sensor” may be a sensor whose output changes in accordance with the turbidity of the sample liquid. Specifically, for example, a light-emitting element and a light-receiving element are arranged to face each other with a gap between them, and a transmission type photosensor that measures the amount of light that passes through the sample liquid that has entered the gap is used, or A scattering type optical sensor that measures the scattered light by arranging the light receiving element obliquely can be used.

  According to the present invention, the collection control unit collects the sample solution in the reservoir, and detects the turbidity of the sample solution in the reservoir by the turbidity sensor. When the detected turbidity exceeds a preset turbidity threshold, the sample liquid is assumed to be turbid, and the turbid state notification unit outputs the occurrence of the turbid state. At this time, the sample injection control unit does not perform the operation of injecting the sample into the furnace, and therefore the atomic absorption is not measured. The sample liquid exchange control unit discards the sample liquid whose turbidity exceeds the threshold value from the reservoir, and collects a new sample liquid and supplies it to the reservoir.

According to the metal concentration monitoring apparatus of the present invention, even when sudden turbidity is observed in the wastewater, the turbidity is detected in advance so that the measurement is not performed and the load on the apparatus is not affected. In addition, by outputting that turbidity has occurred, it is possible to notify that there is an abnormality.

(Means and effects for solving other problems)
In addition, the second invention for solving the above-described problem is that sample liquid is collected in a reservoir, and a part of the collected sample liquid is injected into the furnace of a furnace atomic absorption photometer by a sample injection mechanism to perform atomic absorption measurement. A metal concentration monitoring device that measures the concentration of a metal contained in a sample liquid by performing a sampling control unit that collects the sample liquid at a predetermined time interval and supplies the sample liquid to the reservoir, and the turbidity of the sample liquid in the reservoir A turbidity sensor that detects the occurrence of turbidity when the turbidity of the sample liquid in the reservoir exceeds the threshold value, and turbidity by diluting the sample liquid whose turbidity exceeds the threshold value And a sample injection control unit that injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold value. Be prepared .
That is, in the present invention, the collection control unit collects the sample liquid in the reservoir, and detects the turbidity of the sample liquid in the reservoir by the turbidity sensor. When the detected turbidity exceeds a preset turbidity threshold, the sample liquid is assumed to be turbid, and the turbid state notification unit outputs the occurrence of the turbid state. At this time, the sample injection control unit does not perform the operation of injecting the sample into the furnace, and therefore no measurement is performed. The sample dilution control unit dilutes the sample liquid in the reservoir that has exceeded the turbidity threshold to reduce the turbidity. When the threshold value is not exceeded, the sample injection control unit injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer, and measurement is performed.
As a result, even when sudden turbidity is observed in the drainage, by detecting turbidity in advance, it is possible to prevent the measurement from being performed and to prevent the load on the device from being affected. By outputting that turbidity has occurred, it is possible to notify that there was an abnormality.

Further, a third invention for solving the above-described problem is that sample liquid is collected in a reservoir, and a part of the collected sample liquid is injected into the furnace of a furnace atomic absorption photometer by a sample injection mechanism to perform atomic absorption measurement. A metal concentration monitoring device for measuring the concentration of a metal contained in a sample liquid by performing a sample collecting unit for collecting the sample liquid at a predetermined time interval and supplying the sample liquid to the reservoir, and the turbidity of the sample liquid in the reservoir A turbidity sensor that detects turbidity, a turbidity notification unit that outputs the occurrence of turbidity when the turbidity of the sample liquid in the reservoir exceeds the threshold, and an acidic liquid added to the sample liquid that has exceeded the threshold Acid liquid addition control unit to reduce turbidity and sample injection control to inject a part of the sample liquid into the furnace of the furnace atomic absorption photometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold And so on It is.
That is, in the present invention, the collection control unit collects the sample liquid in the reservoir, and detects the turbidity of the sample liquid in the reservoir by the turbidity sensor. When the detected turbidity exceeds a preset threshold value, the sample liquid is assumed to be cloudy, and the cloudy state notification unit outputs the occurrence of a cloudy state. At this time, the sample injection control unit does not perform the operation of injecting the sample into the furnace, and therefore no measurement is performed. The acidic liquid addition control unit dilutes the acidic liquid (for example, hydrochloric acid, nitric acid, sulfuric acid, etc.) in the sample liquid in the reservoir whose turbidity exceeds the threshold value, and reduces the turbidity by dissolving the metal. When the turbidity of the sample liquid does not exceed the threshold value, the sample injection control unit injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer, and measurement is performed.
As a result, even when sudden turbidity is observed in the drainage, by detecting turbidity in advance, it is possible to prevent the measurement from being performed and to prevent the load on the device from being affected. By outputting that turbidity has occurred, it is possible to notify that there was an abnormality.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, It cannot be overemphasized that various aspects are included in the range which does not deviate from the meaning of this invention.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a metal concentration monitoring apparatus according to an embodiment of the present invention. The metal concentration monitoring device 1 stores a furnace atomic absorption spectrophotometer 11 that measures the concentration of a metal contained in a sample solution, a sample injection mechanism 12, a sample solution supply channel 13, a pump 14, and a sample solution. , A drain channel 16 for discharging the sample liquid in the reservoir 15, a drain valve 17 for opening and closing the drain channel 16, a turbidity sensor 18 attached to the bottom of the reservoir 15, and a control for controlling the entire apparatus. It consists of a system 20 (computer).

  The furnace atomic absorption spectrophotometer 11 includes a light source 11a composed of a hollow cathode lamp, a furnace 11b using a graphite tube heated at a high temperature by energization, a spectroscope and a photodetector, and has a wavelength at which atomic absorption occurs. And a photometric unit 11c for detecting light. A sample injection hole 11d is formed in the furnace 11b, and the sample liquid is injected into the furnace 11b by dropping the sample liquid therefrom.

  The sample injection mechanism 12 includes a support shaft 12a, an arm 12b, a syringe 12c, and a drive mechanism (not shown). The arm 12b rotates around the support shaft 12a and moves up and down in the axial direction of the support shaft 12a. By these movements, the syringe 12c sucks a part of the sample liquid from the reservoir 15, moves onto the sample injection hole 11d of the furnace 11a, and can drop the sample liquid.

  The sample solution supply channel 13 is connected by a pipe from an external channel R (for example, a sewer pipe) through which factory wastewater or the like flows to the reservoir 15, and the sample solution is stored in the reservoir 15 by operating a pump 14 provided in the middle of the channel. To supply.

The reservoir 15 is installed within a range in which the syringe 12c of the sample injection mechanism 12 can move, and the syringe 12c can suck the sample liquid by temporarily storing the sample liquid supplied via the sample liquid supply channel 13. It is like that.
Further, a turbidity sensor 18 is attached to the bottom of the reservoir 15 so as to detect the turbidity of the sample liquid stored in the reservoir 15.

  FIG. 2 is a diagram showing the configuration of the turbidity sensor 18. The turbidity sensor 18 is fixed to a U-shaped frame 18a so that the LED 18b and the photodiode 18c face each other with a gap of several mm. The sample solution enters the gap between the LED 18b and the photodiode 18c. Then, as the turbidity of the sample liquid in the gap increases, the amount of light reaching the photodiode 18c from the LED 18b attenuates, so the turbidity of the sample liquid is determined by measuring the amount of light.

  The drain channel 16 is provided with piping from the bottom of the reservoir 15 through the valve 17 to the external channel R. By opening the valve 17, the sample liquid in the reservoir 15 can be discharged.

Next, the control system 20 will be described.
The control system 20 includes a CPU 21, a memory 22, an input device 23 (keyboard, mouse, etc.) for inputting set values and operation start commands, a display device for displaying the operation state of the device, measurement results, turbidity of the sample liquid, and the like. The computer system is composed of 24 (liquid crystal screen).

  The control system 20 controls various parts of the metal concentration monitoring device 1 by the CPU 21 to calculate and process the program stored in the memory 22 to realize various functions. In order to explain these functions, the control unit 20 is described as a functional block. The control unit 20 includes a collection control unit 31, a turbid state notification unit 32, a sample liquid exchange control unit 33, a sample injection control unit 34, and a measurement control unit 35. .

  The collection controller 31 drives the valve 17 and the pump 14 at predetermined time intervals (for example, every 10 minutes), and performs control to pump the sample solution from the sample solution supply channel 13 to the reservoir 15 and store it. .

  The turbidity state notification unit 32 receives the turbidity signal detected by the turbidity sensor 18 and compares it with the turbidity threshold value stored in the memory 22. When the turbidity signal exceeds the turbidity threshold value, the turbidity state notification unit 32 is in a turbid state. It is determined that there is, and warning information to that effect is transmitted. The warning information is displayed on the display device 24 and is stored in the memory 22 as a part of the measurement result and reflected in the measurement data.

When it is determined that the sample liquid in the reservoir 15 is cloudy, the sample liquid exchange control unit 33 opens the valve 17 and discards the sample liquid stored in the reservoir 15 from the drain flow path 16. Next, the pump 14 is operated to newly pump the sample solution back into the reservoir 15 and control to replace the sample solution in the reservoir 15 is performed.
At this time, in order to give priority to the time interval of periodic collection repeatedly performed by the collection control unit 31, the sample solution exchange and the subsequent absorbance measurement are performed in a time range in which the control time interval by the collection control unit 31 is not destroyed. Like that. Specifically, for example, when the time interval for pumping the sample liquid by the collection control unit 31 is set to 10 minutes, if the sample liquid is determined to be cloudy, the light absorption is performed within 10 minutes, more preferably within 5 minutes. The sample solution is exchanged in about 1 to 3 minutes so that the measurement can be completed.
In addition, when it is determined that the sample liquid is again turbid when the sample liquid is replaced, there is a time margin in relation to the periodic sampling time interval by the sampling control unit 31. The same replacement process may be repeated, but the replacement process is not performed when there is no time margin. Then, processing is performed assuming that the atomic absorption measurement data at that time is missing.

When it is determined that the sample liquid in the reservoir 15 is not in a turbid state, the sample injection control unit 34 operates the sample injection mechanism 12 and applies the sample liquid to the furnace atomic absorption spectrophotometer that is in a standby state in advance. The process which injects a part is performed.
Specifically, the needle tip of the syringe 12c is immersed in the sample liquid in the reservoir 15 and sucked, and then the arm 12b is moved up and down and rotated to move the syringe 12c onto the sample injection hole 11d of the furnace 11b. Control to drop the sample solution.

  The measurement control unit 35 performs lighting control of the light source 11a in the atomic absorption spectrophotometer 11, heating control of the furnace 11b, and measurement control by the photometry unit 11c, and measures atomic absorption of the sample liquid dropped from the sample injection hole 11d. Do.

Next, the measurement operation by the metal concentration monitoring apparatus 1 will be described with reference to the drawings. FIG. 3 is a flowchart showing the procedure of the measurement operation by the metal concentration monitoring apparatus 1.
When the measurement is started, the furnace atomic absorption spectrophotometer 11 is activated, and the furnace is heated to be in a standby state. Further, the liquid in the reservoir 15 (the previously measured sample liquid or the cleaning liquid) is discharged so that the newly measured sample liquid can be stored (S101).

Next, in order to periodically collect the sample solution at a preset time interval, the process waits until the scheduled collection time is reached (S102).
When the scheduled collection time is reached, the pump 14 is activated to draw and store the sample liquid in the reservoir 15 (S103).

  Next, the turbidity sensor 18 is activated to measure the turbidity of the sample liquid in the reservoir 15 and compare with a preset turbidity threshold value (S104). If the turbidity detected by the turbidity sensor 18 does not exceed the turbidity threshold, it is determined that the sample liquid in the reservoir 15 is not turbid, and the process proceeds to S105. On the contrary, if the turbidity threshold is exceeded, it is determined that the sample liquid is in a turbid state, and the process proceeds to S107.

If it is determined in S104 that the sample liquid is not turbid, the sample injection mechanism 12 is operated to suck a part of the sample liquid in the reservoir 15, and the furnace atomic absorption spectrophotometer 11 in the standby state is inspected. It is dropped and injected from the sample injection hole 11d (S105).
Subsequently, the light source 11a is turned on to perform atomic absorption measurement (S106). When the measurement is completed, the measurement result is displayed on the display device 24 and stored in the memory 22 to return to “A” to repeat the next measurement.

  On the other hand, when it is determined in S104 that the sample liquid in the reservoir 15 is cloudy, the display device 24 displays that the sample liquid is cloudy, and the memory 22 indicates that the sample liquid is cloudy. Store (S107). The turbidity state information stored in the memory 22 is output as part of the data when the measurement data is output over time.

Next, the valve 17 is opened to discharge the sample solution in the reservoir 15 (S108). Then, based on the relationship with the remaining time until the next periodic sample liquid collection time, it is determined whether the time necessary for pumping the sample liquid again into the reservoir 15 and performing atomic absorption measurement remains (S109).
Specifically, assuming that a total of about 3 minutes is required until the sample liquid is pumped into the reservoir 15 and a part of the sample liquid is injected into the furnace atomic absorption spectrophotometer 11 to measure atomic absorption, the next sampling time is assumed. If about 5 minutes remain before starting, it is determined that remeasurement is possible, and the process proceeds to S110. On the other hand, if the remaining sampling time is 5 minutes or less until the next sampling time, it is determined that there is no time for re-measurement, and it is determined that measurement was impossible because the turbid state was not improved within the time, and the measurement was not performed. move on.

If it is determined in S109 that remeasurement is possible, the pump 14 is activated to pump up the sample liquid into the reservoir 15 (S110). Then, the process returns to S104, and the subsequent procedure is advanced.
If it is determined in S109 that there is no time for re-measurement, the measurement is stopped because it is impossible to measure in time (S111). And it returns to "A" in order to perform the next measurement.

  Thereafter, the metal concentration monitoring operation in the sample solution is repeated based on the flow of FIG. This makes it possible to measure the metal concentration without overloading the furnace atomic absorption spectrophotometer when the sample solution is cloudy, and when the sample solution is cloudy, information to that effect is provided. Since it is obtained, the presence or absence of abnormality can be reliably grasped.

(Embodiment 2)
FIG. 4 is a block diagram showing a configuration of a metal concentration monitoring device 2 according to another embodiment of the present invention. The same components as those described in FIG. 1 are denoted by the same reference numerals, and a part of the description is omitted. In this embodiment, when the sample solution stored in the reservoir is cloudy, the sample solution is not replaced, but the sample solution is diluted to reduce the turbid state.

For this reason, the metal concentration monitoring device 2 is provided with a diluent tank 41, a dilution channel 42, and a valve 43 in addition to the configuration of the metal concentration monitoring device 1 of FIG. Inexpensive water is used for the diluting liquid stored in the diluting liquid tank 41, but any other liquid may be used as long as it can be used as the diluting liquid.
The control unit 20 includes a sample solution dilution control unit 36 instead of the sample solution exchange control unit 33.

  When it is determined that the sample liquid in the reservoir 15 is cloudy, the sample liquid dilution control unit 36 performs control to dilute the sample liquid stored in the reservoir 15 by opening the valve 43. At this time, the dilution may be increased by opening the valve 17 and discarding a part of the sample solution from the drain channel 16 at the same time. Then, dilution is performed until the turbidity by the turbidity sensor 18 does not exceed the turbidity threshold. By diluting the sample solution in the reservoir 15 in this way, it is possible to prevent a large load from being applied to the atomic absorption spectrophotometer 11.

Next, the measurement operation by the metal concentration monitoring device 2 will be described with reference to the drawings. FIG. 5 is a flowchart showing the procedure of the measurement operation by the metal concentration monitoring device 2.
When the measurement is started, the furnace atomic absorption spectrophotometer 11 is activated, and the furnace is heated to be in a standby state. Further, the liquid in the reservoir 15 (the previously measured sample liquid or the cleaning liquid) is discharged so that the newly measured sample liquid can be stored (S201).

Next, in order to periodically collect the sample solution at a preset time interval, it waits until the scheduled collection time is reached (S202).
When the scheduled collection time is reached, the pump 14 is activated to draw and store the sample solution in the reservoir 15 (S203).

  Next, the turbidity sensor 18 is activated to measure the turbidity of the sample liquid in the reservoir 15 and compare with a preset turbidity threshold (S104). If the turbidity detected by the turbidity sensor 18 does not exceed the turbidity threshold, it is determined that the sample liquid in the reservoir 15 is not turbid, and the process proceeds to S205. Conversely, if the turbidity threshold is exceeded, it is determined that the sample liquid is in a turbid state, and the process proceeds to S207.

If it is determined in S204 that the sample liquid is not turbid, the sample injection mechanism 12 is operated to suck a part of the sample liquid in the reservoir 15, and the furnace atomic absorption spectrophotometer 11 in the standby state is inspected. A sample liquid is dropped and injected from the sample injection hole 11d (S205).
Subsequently, the light source 11a is turned on to perform atomic absorption measurement (S206). When the measurement is completed, the measurement result is displayed on the display device 24 and stored in the memory 22 to return to “A” to repeat the next measurement.

  On the other hand, when it is determined in S204 that the sample liquid in the reservoir 15 is cloudy, the display device 24 displays that the sample liquid is cloudy, and the memory 22 indicates that the sample liquid is cloudy. Store (S207). The turbidity state information stored in the memory 22 is output as part of the data when the measurement data is output over time.

  Next, the valve 43 is opened to dilute the sample solution in the reservoir 15 (S208). Then, the turbid state after dilution is measured by the turbidity sensor 18, and when the turbid state continues, the dilution is further continued. When the turbidity has eased and the turbidity threshold is no longer exceeded, dilution is stopped.

In S205, the sample injection mechanism 12 is operated to suck a part of the sample liquid in the reservoir 15, and the sample liquid is dropped and injected from the sample injection hole 11d of the furnace atomic absorption spectrophotometer 11 in the standby state. (S205).
Subsequently, the light source 11a is turned on to perform atomic absorption measurement (S206). When the measurement is completed, the measurement result is displayed on the display device 24 and stored in the memory 22 to return to “A” to repeat the next measurement.

  Thereafter, the monitoring operation of the metal concentration in the sample solution is repeated based on the flow of FIG. This makes it possible to measure the metal concentration without overloading the furnace atomic absorption spectrophotometer when the sample solution is cloudy, and when the sample solution is cloudy, information to that effect is provided. Since it is obtained, the presence or absence of abnormality can be reliably grasped.

(Embodiment 3)
FIG. 6 is a block diagram showing a configuration of a metal concentration monitoring device 3 according to another embodiment of the present invention. The same components as those described in FIGS. 1 and 4 are given the same reference numerals, and a part of the description is omitted. In this embodiment, when the sample solution stored in the reservoir is cloudy, an acidic solution is added to the sample solution to dissolve the substance that causes turbidity and to reduce the turbid state.

Therefore, in the metal concentration monitoring device 3, in addition to the configuration of the metal concentration monitoring device 1 of FIG. 1, an acidic liquid tank 51, an acidic liquid supply channel 52, and a valve 53 are provided. Hydrochloric acid, nitric acid, sulfuric acid or a mixture of these is used as the acidic liquid stored in the acidic liquid tank 51, but any other chemical liquid can be used as long as it can dissolve substances that cause turbidity contained in the sample liquid. It may be.
In addition, the control unit 20 includes an acidic liquid addition control unit 37 instead of the sample liquid exchange control unit 33.

  The acidic liquid addition control unit 37 performs control to open the valve 53 and add the acidic liquid stored in the reservoir 15 when it is determined that the sample liquid in the reservoir 15 is cloudy. Addition is performed until the turbidity by the turbidity sensor 18 does not exceed the turbidity threshold. By adding an acidic solution to the sample solution in the reservoir 15, it is possible to prevent a large load from being applied to the atomic absorption spectrophotometer 11.

Next, the measurement operation by the metal concentration monitoring device 3 will be described with reference to the drawings. FIG. 7 is a flowchart showing the procedure of the measurement operation by the metal concentration monitoring device 3.
When the measurement is started, the furnace atomic absorption spectrophotometer 11 is activated, and the furnace is heated to be in a standby state. Further, the liquid in the reservoir 15 (the previously measured sample liquid or the cleaning liquid) is discharged so that the newly measured sample liquid can be stored (S301).

Next, in order to periodically collect the sample solution at a preset time interval, the process waits until the scheduled collection time is reached (S302).
When the scheduled collection time is reached, the pump 14 is activated to draw and store the sample solution in the reservoir 15 (S303).

  Next, the turbidity sensor 18 is activated to measure the turbidity of the sample liquid in the reservoir 15 and compare with a preset turbidity threshold (S304). If the turbidity detected by the turbidity sensor 18 does not exceed the turbidity threshold, it is determined that the sample liquid in the reservoir 15 is not turbid, and the process proceeds to S305. Conversely, if the turbidity threshold is exceeded, it is determined that the sample solution is in a turbid state, and the process proceeds to S307.

If it is determined in S304 that the sample liquid is not turbid, the sample injection mechanism 12 is operated to suck a part of the sample liquid in the reservoir 15, and the furnace atomic absorption spectrophotometer 11 in the standby state A sample solution is dropped and injected from the sample injection hole 11d (S305).
Subsequently, the light source 11a is turned on to perform atomic absorption measurement (S306). When the measurement is completed, the measurement result is displayed on the display device 24 and stored in the memory 22 to return to “A” to repeat the next measurement.

  On the other hand, when it is determined in S304 that the sample liquid in the reservoir 15 is cloudy, the display 24 displays that the sample liquid is cloudy, and the memory 22 indicates that the sample liquid is cloudy. Store (S307). The turbidity state information stored in the memory 22 is output as part of the data when the measurement data is output over time.

  Next, the valve 53 is opened to add the acidic solution into the reservoir 15 (S308). Then, the turbid state after the addition is measured by the turbidity sensor 18, and when the turbid state is not improved, further dilution is continued. Addition is stopped when the turbidity has eased and the turbidity threshold is no longer exceeded.

In step S305, the sample injection mechanism 12 is operated to suck a part of the sample liquid in the reservoir 15, and the sample liquid is dropped and injected from the sample injection hole 11d of the furnace atomic absorption spectrophotometer 11 in the standby state. (S305).
Subsequently, the light source 11a is turned on to perform atomic absorption measurement (S306). When the measurement is completed, the measurement result is displayed on the display device 24 and stored in the memory 22 to return to “A” to repeat the next measurement.

  Thereafter, the monitoring operation of the metal concentration in the sample solution is repeated based on the flow of FIG. This makes it possible to measure the metal concentration without overloading the furnace atomic absorption spectrophotometer when the sample solution is cloudy, and when the sample solution is cloudy, information to that effect is provided. Since it is obtained, the presence or absence of abnormality can be reliably grasped.

(Other embodiments)
In the above-described embodiment, the sample supply flow path is only one system. However, a plurality of sample supply flow paths with different intakes are provided in parallel, and a plurality of systems are provided so that a pump is provided for each. Measurements may be performed in order. According to this, the metal concentration can be monitored over a wide area of the drainage channel.

  INDUSTRIAL APPLICABILITY The present invention can be used as a metal concentration monitoring device (metal in-line monitor) that constantly monitors the metal concentration contained in factory wastewater or the like.

The block diagram which shows the structure of the metal concentration monitoring apparatus which is one Embodiment of this invention. The figure which shows an example of a turbidity sensor. The flowchart which shows the measurement operation | movement by the metal concentration monitoring apparatus of FIG. The block diagram which shows the structure of the metal concentration monitoring apparatus which is other one Embodiment of this invention. The flowchart which shows the measurement operation | movement by the metal concentration monitoring apparatus of FIG. The block diagram which shows the structure of the metal concentration monitoring apparatus which is other one Embodiment of this invention. The flowchart which shows the measurement operation | movement by the metal concentration monitoring apparatus of FIG.

Explanation of symbols

1, 2, 3: Metal concentration monitoring device 11: Furnace atomic absorption spectrophotometer 12: Sample injection mechanism 13: Sample liquid supply channel 14: Pump 15: Reservoir 16: Drain channel 17: Valve 18: Turbidity sensor 20: Control system 31: Collection control unit 32: Turbidity state notification unit 33: Sample solution exchange control unit 34: Sample injection control unit 35: Measurement control unit 36: Sample solution dilution control unit 37: Acid solution addition control unit

Claims (3)

Metal that measures the concentration of metal contained in the sample liquid by collecting the sample liquid in the reservoir and injecting a portion of the collected sample liquid into the furnace of the furnace atomic absorption photometer using the sample injection mechanism and performing atomic absorption measurement A concentration monitoring device,
A collection control unit that collects a sample solution at a predetermined time interval and supplies the sample solution to the reservoir;
A turbidity sensor for detecting the turbidity of the sample liquid in the reservoir;
A turbidity state notification unit that outputs the occurrence of a turbid state when the turbidity of the sample liquid in the reservoir exceeds a threshold;
A sample liquid exchange control unit for discarding a sample liquid whose turbidity exceeds a threshold value from the reservoir and collecting a new sample liquid and supplying the sample liquid to the reservoir;
Metal concentration monitoring characterized by comprising a sample injection control unit that injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold apparatus. Metal that measures the concentration of metal contained in the sample liquid by collecting the sample liquid in the reservoir and injecting a portion of the collected sample liquid into the furnace of the furnace atomic absorption photometer using the sample injection mechanism and performing atomic absorption measurement A concentration monitoring device,
A collection control unit that collects a sample solution at a predetermined time interval and supplies the sample solution to the reservoir;
A turbidity sensor for detecting the turbidity of the sample liquid in the reservoir;
A turbidity state notification unit that outputs the occurrence of a turbid state when the turbidity of the sample liquid in the reservoir exceeds a threshold;
A sample solution dilution control unit that dilutes a sample solution whose turbidity exceeds a threshold value to reduce turbidity, and
Metal concentration monitoring characterized by comprising a sample injection control unit that injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold apparatus. Metal that measures the concentration of metal contained in the sample liquid by collecting the sample liquid in the reservoir and injecting a portion of the collected sample liquid into the furnace of the furnace atomic absorption photometer using the sample injection mechanism and performing atomic absorption measurement A concentration monitoring device,
A collection control unit that collects a sample solution at a predetermined time interval and supplies the sample solution to the reservoir;
A turbidity sensor for detecting the turbidity of the sample liquid in the reservoir;
A turbidity state notification unit that outputs the occurrence of a turbid state when the turbidity of the sample liquid in the reservoir exceeds a threshold;
An acidic liquid addition control unit that reduces the turbidity by adding an acidic liquid to a sample liquid whose turbidity exceeds a threshold; and
Metal concentration monitoring characterized by comprising a sample injection control unit that injects a part of the sample liquid into the furnace of the furnace atomic absorption photometer when the turbidity of the sample liquid in the reservoir does not exceed the threshold apparatus.

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