JP2013015387A - Water quality analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent measurement accuracy from being reduced in measurement after resuming the circulation of carrier gas or measurement water, even if the circulation of carrier gas or measurement water is stopped while the measurement is suspended.SOLUTION: An arithmetic control section 56 controls a gas purification/flow control section 40 to stop supplying carrier gas while measurement is suspended, and prevents the measurement of a sample from being started before the lapse of a predetermined standby time from the start of carrier gas supply. The standby time is set on the basis of a carrier gas supply stop time measured by a stop time measuring section 58.

Description

  The present invention relates to a water quality analyzer used for measuring pollutant components contained in sewage, river water, factory effluent and the like.

  Some water quality analyzers measure total organic carbon (TOC) and total nitrogen (TN) contained in a sample, and others can be measured with a single measuring device.

  The TOC meter is an apparatus that quantifies the organic matter concentration contained in the organic matter by oxidizing the organic matter contained in the sample water to convert it into carbon dioxide and measuring the carbon dioxide concentration. There are two types of methods for oxidizing organic matter: a combustion-type oxidation method that burns and oxidizes organic matter in a high-temperature furnace and a wet oxidation method that oxidizes organic matter using ultraviolet light.

  The combustion oxidation type TOC meter injects sample water into a catalyst-containing combustion tube housed in a heating furnace, oxidizes the carbon component in the sample and converts it into carbon dioxide, and the gas containing the carbon dioxide is used as a carrier. The concentration of carbon dioxide in the gas is measured by sending the gas to the cell of the detection unit, and the TOC is quantified based on the measured value (for example, see Patent Document 1). As the detector, a non-dispersive infrared absorption detector is generally used.

  The wet oxidation TOC meter includes an IC (inorganic carbon) removal unit, an oxidation reaction unit, a carbon dioxide extraction unit, and a conductivity measurement unit as a detection unit. The sample water is made acidic to facilitate removal of dissolved IC, and after the IC is removed in the IC removal section, it is led to the oxidation reaction section. In the oxidation reaction part, organic matter in the sample water is oxidized and decomposed by being irradiated with ultraviolet rays, and converted into carbon dioxide. The sample water that has passed through the oxidation reaction section is introduced into the carbon dioxide extraction section, where carbon dioxide in the sample water permeates through the gas-liquid separation membrane when the sample water contacts the measurement water via the gas-liquid separation membrane. Shift to measuring water. The measured water obtained by extracting carbon dioxide from the sample water is measured for conductivity in the conductivity measuring unit, and converted to carbon dioxide concentration (TOC concentration). In the wet oxidation TOC meter, deionized water from which impurities such as carbon dioxide have been removed by the ion exchange unit is used as the measurement water flowing through the carbon dioxide extraction unit (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 11-352058 Japanese Patent Laid-Open No. 2010-216977

  A water quality analyzer such as a TOC meter may perform measurement intermittently with a certain period between measurements.

  In the combustion oxidation type TOC meter, it is general that the carrier gas is always circulated in the detection flow path leading to the detection unit while the measurement is interrupted. For this reason, when cylinder gas is used as the carrier gas, a large amount of cylinder gas is consumed, resulting in a waste. Also, even when the carrier gas is purified by taking in outside air and removing unnecessary components, the carrier gas purifying unit is always operated even during measurement interruption, thereby accelerating the deterioration of the removing unit that removes unnecessary components. There is a problem.

  The same applies to the TOC meter of the wet oxidation method, and it is general that the measurement water is always circulated from the measurement water supply unit to the measurement water flow channel leading to the detection unit while the measurement is interrupted. Therefore, when pure water stored in a tank is used as measurement water, a large amount of pure water is consumed. It is also possible to use an ion exchange resin placed in the flow path of the measurement water, and a circulation flow path that uses the ion exchange resin to deionize the measurement water that has passed through the detection unit to form the measurement water. . Even in that case, there is a problem that the ion exchange resin is always deteriorated by always using the ion exchange resin.

  However, if the flow of the carrier gas or the measurement water is stopped while the measurement is interrupted, there is a problem that the baseline of the detection signal is not stable and an accurate measurement cannot be performed. This phenomenon was noticeable when a resin tube was used as the carrier gas flow path or the measurement water flow path. Therefore, the carrier gas flow path was stopped while the flow of the carrier gas or measurement water was stopped. This is probably because carbon dioxide in the outside air diffuses into the carrier gas or measurement water through the wall surface of the measurement water flow path and changes the detection signal in the detection unit. Therefore, it is considered that the detection signal was not stable because the sample was measured with carbon dioxide diffused from the outside air remaining in the carrier gas. Even when a resin tube is not used as the carrier gas flow path or the measurement water flow path, carbon dioxide in the outside air can diffuse from the connection portion of the flow path.

  Therefore, the present invention prevents the measurement accuracy in the measurement after the circulation of the carrier gas or the measurement water from being lowered even if the circulation of the carrier gas or the measurement water is stopped while the measurement is interrupted. It is for the purpose.

  The water quality analyzer of the present invention can be applied regardless of whether the oxidation reaction part is a combustion oxidation type or a wet oxidation type.

  When the oxidation reaction unit is of the combustion oxidation type, the water quality analyzer is equipped with an oxidation reaction unit that oxidizes the measurement components in the sample water introduced with a combustion tube and converts it into an oxidizing gas, and sample water in the oxidation reaction unit. A sample introduction unit to be introduced, a detection unit that includes a measurement cell and measures the concentration of the oxidizing gas in the measurement cell, and a carrier gas supply unit that sends a gas containing the oxidation gas in the oxidation reaction unit to the detection unit cell by the carrier gas And a control unit for controlling the sample introduction unit and the carrier gas supply unit. The oxidizing gas contains carbon oxide and nitrogen oxide.

  In the case of a combustion oxidation water quality analyzer, the concentration of the oxidizing gas in the carrier gas in the flow path from the carrier gas supply unit to the detection unit when the carrier gas supply in the carrier gas supply unit is stopped is saturated. The carrier gas supply stop time T until reaching the state or the detection signal value S by the detection unit by the carrier gas in the saturated state and the oxidizing gas concentration in the carrier gas in the flow path from the carrier gas supply unit to the detection unit are saturated A standby time information holding unit that holds, as standby time information, a time t from when the carrier gas supply unit starts supplying the carrier gas to the time when the detection signal of the oxidizing gas disappears at the detection unit; When the supply of carrier gas is started at the start of measurement, the measured value T ′ of the carrier gas supply stop time in the carrier gas supply unit or the carrier by the detection unit Detection unit signal value s, waiting time information T or S held in the waiting time information holding unit, and a calculation unit that calculates a waiting time t ′ from t to the introduction of sample water. When the measurement is not being performed, the carrier gas supply at the carrier gas supply unit is stopped, the carrier gas supply at the carrier gas supply unit is started at the start of measurement, and the carrier gas supply is started. After the calculated waiting time t ′ has elapsed, the sample introduction unit starts to introduce sample water into the oxidation reaction unit.

  When the oxidation reaction part is a wet oxidation type, the water quality analyzer introduces sample water into the oxidation reaction part that oxidizes the carbon component in the introduced sample water by ultraviolet irradiation to convert it into carbon dioxide, and the oxidation reaction part A sample introduction unit and a carbon dioxide extraction unit that includes a gas-liquid separation membrane and causes the measurement water and the sample water that has passed through the oxidation reaction unit to contact with each other through the gas-liquid separation membrane to transfer carbon dioxide in the sample water to the measurement water. A measurement water supply unit that includes an ion exchange unit and supplies deionized water from the ion exchange unit as measurement water to the carbon dioxide extraction unit, a detection unit that measures the conductivity of the measurement water from the carbon dioxide extraction unit, A control unit that controls the sample introduction unit and the measurement water supply unit.

  In the case of a wet oxidation water quality analyzer, the concentration of carbon dioxide in the measurement water in the flow path from the measurement water supply unit to the detection unit when the measurement water supply in the measurement water supply unit is stopped is saturated. Measured water supply stop time T until it becomes or the detection signal value S by the detection unit by the measured water in its saturated state, and the carbon dioxide concentration in the measured water in the flow path from the measured water supply unit to the detection unit are saturated A waiting time information holding unit that holds, as waiting time information, a time t from when there is no carbon dioxide detection signal at the detection unit when the measurement water supply unit starts supplying measurement water, and starts measurement Sometimes when the measurement water supply is started, the measurement water supply stop time measurement value T ′ at the measurement water supply unit or the detection signal value s of the measurement water by the detection unit and the waiting time information holding unit are held. Waiting time information T or S; a calculation unit that calculates a waiting time t ′ from t to the introduction of sample water, and the control unit stops measurement water supply at the measurement water supply unit when measurement is not being performed, and performs measurement at the start of measurement. Start supplying sample water in the water supply unit, and start sample water introduction to the oxidation reaction unit by the sample introduction unit after the waiting time t ′ calculated by the calculation unit has elapsed since the start of the measurement water supply Is configured to do.

  In the case of a combustion oxidation water quality analyzer, the carbon dioxide concentration in the carrier gas in the flow path from the carrier gas supply unit to the detection unit when the carrier gas supply in the carrier gas supply unit is stopped becomes saturated. The carrier gas supply stop time T until the time can be obtained experimentally by measuring the relationship between the carrier gas supply stop time and the detection signal when the carrier gas after the supply stop time is detected by introducing it to the detector. it can. The detection signal value S by the detection unit using the carrier gas in the saturated state can also be obtained in this way. When the carbon dioxide concentration in the carrier gas in the flow path from the carrier gas supply unit to the detection unit is saturated, when the carrier gas supply from the carrier gas supply unit is started, the detection signal of carbon dioxide at the detection unit is The time t until it can be eliminated can also be obtained experimentally.

  In the case of a wet oxidation water quality analyzer, until the carbon dioxide concentration in the measurement water in the flow path from the measurement water supply unit to the detection unit is saturated when the supply of the measurement water in the measurement water supply unit is stopped The measured water supply stop time T can also be obtained experimentally by measuring the relationship between the measured water supply stop time and the detection signal when the measured water after the supply stop time is detected by being guided to the detection unit. . The detection signal value S by the detection unit with the measured water in the saturated state can also be obtained in this way. When the carbon dioxide concentration in the measurement water in the flow path from the measurement water supply unit to the detection unit is in a saturated state, the detection signal of carbon dioxide at the detection unit disappears when the measurement water supply unit starts supplying the measurement water The time t until can be obtained experimentally.

  Since these values T, S, and t are device constants determined by the design of the water quality analyzer, if the standard device is experimentally obtained, other devices can be held as device constants. Of course, these values T, S, and t may be obtained by experiments and held individually for each water quality analyzer.

  According to the water quality analyzer of the present invention, the supply of the carrier gas or the measurement water is stopped during the interruption of the measurement, and the measurement is not performed until the detection signal of the detection unit becomes stable when the supply of the carrier gas or the measurement water is resumed. Therefore, the measurement after restarting the supply of the carrier gas or the measurement water is not started in the unstable state of the baseline of the detection signal, and the measurement accuracy in the measurement started after the measurement is interrupted. Decline can be prevented.

It is a schematic block diagram which shows one Example of the combustion oxidation type | mold TOC meter which is one of the water quality analyzers. It is a graph which shows the time change of the detection signal of a detection part (infrared gas analysis part) when supply of carrier gas is stopped temporarily and supply of carrier gas is restarted after that in the example. It is a flowchart for demonstrating operation | movement of the Example. It is a schematic block diagram which shows one Example of the wet oxidation type | mold TOC meter which is another form of a water quality analyzer.

In one preferred embodiment of the present invention, the calculation unit uses the measured value T ′ of the carrier gas supply stop time or the measured water supply stop time,
If T '<T,
t ′ = t × T ′ / T,
If T ′ ≧ T,
t '= t
The waiting time t ′ is obtained and set as follows.

  In another preferred embodiment, the waiting time information holding unit holds one or a plurality of reference times shorter than T and T as waiting time information, and waiting times corresponding to T and each reference time. The arithmetic unit compares the measured value T ′ of the carrier gas supply stop time or the measured water supply stop time with T and the reference time held in the standby time information holding unit, and is held in the standby time information holding unit. The corresponding waiting time is set as the waiting time t ′.

In the above two embodiments, the standby time t ′ is set based on the measurement value T ′ of the stop time. On the other hand, t ′ can be set based on the detection signal value s.
One of such preferred embodiments is that the standby time calculation unit is configured to start the carrier gas detection signal value s or the measurement water when the carrier gas supply is started at the start of measurement. The detection signal value s of the measurement water by the detection unit is captured, and from the standby time information S and t held in the standby time information holding unit,
If s <S,
t ′ = t × s / S,
If T ′ ≧ T,
t '= t
The waiting time t ′ is obtained and set as follows.

  Further, in another preferred embodiment in which t ′ is set based on the detection signal value s, the standby time information holding unit includes one or more reference signal levels smaller than S and S as standby time information, and S and The standby time corresponding to each reference signal level is held, and the calculation unit starts supplying the carrier gas detection signal value s or the measurement water when the measurement starts. The detection signal value s of the measured water by the detection unit at the time is taken, the detection signal value s is compared with the S and reference signal level held in the standby time information holding unit, and the correspondence held in the standby time information holding unit This waiting time is set as the waiting time t ′.

  Examples of the carbon component to be measured in the sample water include total organic carbon, and the water quality analyzer can be used as the total organic carbon measuring device.

[Example 1]
Hereinafter, a more specific embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a TOC / TN meter capable of measuring both TOC and TN as a water quality analyzer to which the present invention is applied.

  A flow path for discharging a part of the sample to the drain outlet 12 through the branch part 3 in the TOC / TN meter main body is connected to the water sampling tube 1 through which a sample such as environmental water continuously flows. One port of the 8-port valve 14 of the sample injection mechanism 18 that is a sample introduction unit for guiding the collected sample to the analysis unit is connected to the branch unit 3.

The sample injection mechanism 18 includes an 8-port valve 14 and a microsyringe 16 connected thereto, and the microsyringe 16 is connected to a common port so that it can be connected to any port of the 8-port valve 14. Each port of the 8-port valve 14 has, in addition to the branching portion 3, an acid addition portion 20 added to make the sample acidic when measuring inorganic carbon (IC), a standard solution 22 for calibration, dilution, Dilution water 24 for use in cleaning, off-line sample 26, sample injection part 34 of TC (total carbon) oxidation reaction part 32 equipped with a catalyst for converting all the carbon components in the sample into CO ₂ , unnecessary gas A drain outlet 28 for discharging and a drain outlet 12 for discharging unnecessary liquid are respectively connected.

  A gas refining / flow rate control unit 40 is provided for removing a carbon component from the air taken in from the air inlet 42 to generate a purified gas, adjusting the flow rate, and sending it out. At the gas outlet of the gas purification / flow rate control unit 40, a flow path 41a for supplying the purified gas generated by the gas purification / flow rate control unit 40 to the microsyringe 16 as a sparge gas or a carrier gas, and a TC oxidation reaction unit 32 as a carrier gas. A flow path 41b for supplying purified gas and a flow path 41c for supplying purified gas to the ozone generator 50 are connected.

The TC oxidation reaction unit 32 introduces the sample and the carrier gas into the TC combustion tube 36 filled with an oxidation catalyst that converts the carbon component in the sample into CO ₂ and converts the nitrogen component into NO, and the TC combustion tube 36. It comprises a sample injection section 34 and a heating furnace 38 for heating the TC combustion tube 36.
The downstream portion of the TC combustion pipe 36 is connected to an infrared gas analysis unit 46 that detects CO ₂ via a dehumidifier that removes moisture and a dehumidification / gas treatment unit 44 that includes a halogen scrubber that removes halogen components. Yes. The downstream part of the infrared gas analyzer 46 is connected to a chemiluminescence analyzer 48 for detecting NO. Ozone is supplied from the ozone generator 50 to the chemiluminescence analyzer 48. A downstream portion of the chemiluminescence analysis unit 48 is connected to a drain outlet 54 via an ozone killer 52. The infrared gas analysis part 46 and the chemiluminescence analysis part 48 constitute a detection part, and the flow path leading to the infrared gas analysis part 46 and the chemiluminescence analysis part 48 constitutes a detection flow path.

  An operation control unit 56 for controlling the operation of the TOC / TN meter and an arithmetic process, a stop time measuring unit 58 for measuring the stop time of the supply of the carrier gas by the gas purification / flow rate control unit 40, a TOC Alternatively, a standby time information holding unit 59 used to set a standby time before sample injection when starting TN measurement is provided.

  The arithmetic control unit 56 controls operations of the 8-port valve 14, the microsyringe 16, the gas purification / flow rate control unit 40, and the stop time measurement unit 58. The arithmetic control unit 56 takes in output signals from the infrared gas analysis unit 46 and the chemiluminescence analysis unit 48 and performs calculations for obtaining TOC and TN. An input means 60 such as a keyboard and a recorder 62 are connected to the arithmetic control unit 56. The arithmetic control unit 56 is realized by a CPU (central processing unit) and a storage device.

  The arithmetic control unit 56 is configured to control the gas purification / flow rate control unit 40 to stop supplying the carrier gas when the measurement is interrupted. When the supply of the carrier gas is stopped, if carbon dioxide in the outside air diffuses into the flow path leading to the infrared gas analyzer 46 and the infrared gas analyzer 6 is operated, as shown in FIG. The detection signal of the gas analyzer 46 increases. When measurement is started in this state, the measurement is performed in a state where the baseline of the detection signal of the infrared gas analyzer 46 is not stable, and the accuracy of the measurement is impaired. Therefore, the arithmetic control unit 56 is configured not to introduce the sample into the oxidation reaction unit 32 until a predetermined standby time has elapsed after the supply of the carrier gas is started.

The waiting time before starting the measurement of the sample is set as follows.
The stop time measuring unit 58 measures the time during which the supply of the carrier gas by the gas purification / distribution control unit 40 is stopped. There is a certain degree of correlation between the time during which the supply of the carrier gas is stopped and the detection signal of the infrared gas analyzer 6 when the infrared gas analyzer 46 is operated, as shown in FIG. There is a relationship. The correlation as shown in FIG. 2 is obtained in advance by measurement and is held in the standby time information holding unit 59.

The calculation control unit 56 takes a time T required until the detection signal of the infrared gas analysis unit 46 becomes stable due to saturation after the supply of the carrier gas is stopped by the information held in the standby time information holding unit 59. In addition, the time t required until the detection signal of the detection unit becomes stable after the supply of the carrier gas is resumed in a saturated state is obtained, and the information and the stop time measurement unit 58 measure the information. Using the stop time T ′
If T '<T,
t ′ = t × T ′ / T
If T ′ ≧ T,
t '= t
The standby time t ′ is set by calculating

Further, as another method of setting the standby time t ′, the standby time t ′ is stopped after the carrier gas supply is stopped until the time T required until the detection signal of the infrared gas analyzer 46 becomes stable due to saturation. A time threshold T1 and a waiting time t1 corresponding to the time T1 are set. Then, the stop time T ′ measured by the stop time measuring unit 58 is compared with T1,
When T ′ ≦ T1, t ′ = 0
When T ′> T1, t ′ = t1
The standby time t ′ may be set as follows. The threshold value is not limited to one, and two or more threshold values and standby times corresponding to the threshold values may be set.

Since the arithmetic processing unit 56 is configured in this way, the overall flow of the operation of the TOC / TN meter is as shown in FIG.
Before starting the measurement, first, the arithmetic processing unit 56 takes in the time during which the supply of the carrier gas has been stopped from the stop time measuring unit 58 and uses the information in the standby time information holding unit 59 to wait for the standby time. t 'is set. At this time, the supply of the carrier gas from the gas purification / distribution control unit 40 has been stopped since the previous measurement was completed.

  Thereafter, the supply of the carrier gas is started, but the sample injection mechanism 18 stands by without injecting the sample into the oxidation reaction section 32 until the standby time t ′ elapses. After the waiting time t ′ has elapsed, the sample injection mechanism 18 injects a sample into the oxidation reaction unit 32 and starts measurement. When the measurement is completed, supply of the carrier gas from the gas purification / distribution control unit 40 is stopped. . When the supply of the carrier gas from the gas purification / distribution control unit 40 is stopped, the stop time measuring unit 58 starts measuring the stop time. The stop time is measured until the next measurement is started, and the stop time is used for setting the standby time t ′ before the next measurement.

In addition, the standby time t ′ can be set based on the detection signal of the infrared gas analyzer 46 immediately before the supply of the carrier gas is resumed. In this case, the arithmetic processing unit 56 uses the information in the standby time information holding unit 59 to detect the detection signal S and the detection signal S when the detection signal of the infrared gas analysis unit 46 becomes stable after the supply of the carrier gas is stopped. A time t required until the detection signal of the infrared gas analyzer 46 becomes stable after the supply of the carrier gas is resumed in a saturated state is obtained, and immediately before the supply of the information and the carrier gas is resumed. Using the detection signal s,
If s <S,
t ′ = t × s / S
If s ≧ S,
t '= t
Is set to set the waiting time t ′. Since the carrier gas supply stop time is not used in the process of setting the standby time t ′, the stop time measuring unit 58 may be omitted from the configuration of the apparatus.

As described above, also in the method of setting the standby time t ′ using the detection signals S and s of the infrared gas analyzer 46, the carrier gas is supplied and the detection signal of the infrared gas analyzer 46 is stabilized. A threshold value S1 is set between the detection signal when the carrier gas is stopped and the detection signal S when the detection signal of the infrared gas analyzer 46 is stable after the supply of the carrier gas is stopped. A waiting time t1 is set according to the above. Then, the detection signal s of the infrared gas analyzer 46 immediately before the restart of the supply of the carrier gas is compared with the threshold value S1,
When s ≦ S1, t ′ = 0
When s> S1, t ′ = t1
The standby time t ′ may be set as follows. The threshold value is not limited to one, and two or more threshold values and standby times corresponding to the threshold values may be set.

Next, returning to FIG. 1, operations of TC measurement, TN measurement, and TOC measurement in the same embodiment will be described.
(TC measurement and TN measurement)
In response to a control signal from the control unit 58, the microsyringe 16 is connected to the branching unit 3 by the 8-port valve 14, and the microsyringe 16 is driven to sample a certain amount of sample into the microsyringe 16. When a predetermined dilution rate is set, the microsyringe 16 is connected to the dilution water 24 and a predetermined amount of dilution water is added to the sample in the microsyringe 16.

Next, the sample in the microsyringe 16 is injected into the TC combustion tube 36 through the sample inlet 34 of the TC oxidation reaction section 32, and the carbon component in the sample is converted into CO ₂ and the nitrogen component is converted into NO. .
The CO ₂ and NO generated in the TC combustion pipe 36 are sent from the gas purification / flow rate control unit 40 to the dehumidification / gas processing unit 44 together with the supplied carrier gas through the flow path 41b, where they are cooled, dehumidified and halogen-removed. After that, CO ₂ is detected by the infrared gas analyzer 46, and subsequently NO is detected by the chemiluminescence analyzer 48. These detection signals are sent to the calculation unit 56, and the peak area value is obtained from the signal, and the TC concentration and the TN concentration are obtained based on the calibration curve.

(IC measurement, TOC measurement)
A certain amount of sample is collected in the microsyringe 16 in the same manner as in the TC measurement and the TN measurement. When a predetermined dilution rate is set, the microsyringe 16 is connected to the dilution water 24 and a predetermined amount of dilution water is added to the sample in the microsyringe 16.

Next, the microsyringe 16 is connected to the acid addition unit 20 and a small amount of acid is added to the sample in the microsyringe 16. Thereafter, the microsyringe 16 is connected to the sample injection port 34, and the sparge gas is supplied from the gas purification / flow rate control unit 40 to the microsyringe 16 through the flow path 41 a. CO ₂ generated from the IC in the sample is sent to the TC combustion tube 36 dehumidified gas processing unit 44 via with sparge gas, cooling, after being dehumidified and halogen removal, CO ₂ is detected by the infrared gas analyzer 46 . The detection signal is sent to the calculation unit 56, the peak area value is obtained from the signal, and the IC concentration is obtained based on the calibration curve.
In the calculation unit 56, the TOC concentration is also obtained from the difference between the TC concentration and the IC concentration.

The TOC concentration can also be measured alone. A certain amount of sample is collected in the microsyringe 16 in the same manner as in TC measurement and TN measurement. When a predetermined dilution rate is set, the microsyringe 16 is connected to the pure water 24 and a predetermined amount of pure water is added to the sample in the microsyringe 16. Next, the microsyringe 16 is connected to the acid 20 and a small amount of acid is added to the sample in the microsyringe 16. Next, the microsyringe 16 is connected to the drain outlet 28, and the sparge gas is supplied to the microsyringe 16 from the gas purification / flow rate control unit 40 through the flow path 41 a. CO ₂ generated from the IC in the sample is discharged from the drain outlet 28 together with the sparge gas, and the TOC remains in the microsyringe 16. Thereafter, samples of the microsyringe 16 is injected into the TC combustion tube 36 via the TC sample injection port 34 of the TC oxidative reaction part 32, the carbon component in the sample is converted to CO _2, CO ₂ generated by the TC combustion tube 36 Is sent to the infrared gas analysis unit 46 through the dehumidification / gas processing unit 44 together with the carrier gas, and TOC is detected as CO ₂ .

  In this embodiment, the stop time measuring unit 58 and the standby time information holding unit 59 are provided independently of the calculation control unit 56, but one of the stop time measuring unit 58 and the standby time information holding unit 59 or Both may be realized as one function of the arithmetic control unit 56.

[Example 2]
In Example 1, the present invention is applied to an apparatus that transports a sample using a carrier gas, but the present invention can also be applied to an apparatus that uses pure water as measurement water. One example thereof will be described below with reference to FIG.

  The pH adjusting unit 104 is composed of, for example, two flow path substrates stacked with an ion exchange membrane interposed therebetween, and a structure in which the sample water and the pH adjusting solution are in contact with each other through the ion exchange membrane. It has become. Electrodes are respectively provided at the bottoms of the flow paths inside the pH adjusting unit 104, and a voltage is applied between the electrodes. The pH adjusting liquid flow path 114 is a flow path for circulating the pH adjusting liquid stored in the pH adjusting liquid reservoir 116. By applying a voltage between the electrodes of the pH adjusting unit 104, ion exchange is performed between the sample water and the pH adjusting solution, the sample water becomes acidic, and the IC (inorganic carbon) in the sample water is carbon dioxide. Is converted to

  The oxidation reaction unit 108 irradiates the sample water flowing through the sample water channel 102 with ultraviolet rays having a short wavelength, thereby oxidizing and decomposing organic matter in the sample water into carbon dioxide.

  The carbon dioxide extraction unit 110 is composed of, for example, two substrates stacked with a gas-liquid separation membrane interposed therebetween, and the sample water flow channel 102 is located at a position opposite to the surface of each substrate on the gas-liquid separation membrane side. In addition, a flow path that forms part of the measurement water flow path 118 is formed. The sample water flowing through the sample water channel 102 of the gas-liquid separation membrane 110 contains carbon dioxide produced by oxidative decomposition of the organic matter contained in the sample water in the oxidation reaction unit 108. Since the water flow path 118 is in contact with the gas-liquid separation membrane, only carbon dioxide, which is a gas component, passes through the gas-liquid separation film and moves to the measurement water flow path 118 side.

  In the measurement water channel 118, the measurement water is fed by the liquid feed pump 123, and the measurement water is in the order of the measurement water reservoir 120, the ion exchange unit 122, the carbon dioxide extraction unit 110, the conductivity measurement unit 124, and the measurement water reservoir 120. Circulates. After the impurities such as carbon dioxide are removed from the measurement water stored in the measurement water reservoir 120 by the ion exchange unit 122, the carbon dioxide extracted from the sample water is held in the carbon dioxide extraction unit 110, and the conductivity measurement unit 124. The conductivity is measured at

In the ion exchange part 122, impurities are removed by passing measurement water through the ion exchange membrane.
The conductivity measuring unit 124 measures the conductivity of the measurement water that has passed through the carbon dioxide extraction unit 110. The conductivity obtained by the conductivity measuring unit 124 is input to the calculation control unit 126 described later. The arithmetic control unit 126 obtains the concentration of carbon dioxide transferred from the sample water to the measurement water in the carbon dioxide extraction unit 110 based on the measurement result of the conductivity of the measurement water passed through the carbon dioxide extraction unit 110 by the conductivity measurement unit 124. Quantify the TOC of the sample water from the amount of carbon dioxide.

  The anion recovery unit 112 is composed of two substrates stacked with an ion exchange membrane interposed therebetween, and one of the sample water flow channel 102 and the pH adjustment liquid flow channel 114 is formed on the surface of the substrates on the ion exchange membrane side. The flow path which forms a part is formed. Electrodes are formed on the bottom surfaces of the respective flow paths inside the two substrates. When a voltage is applied between both electrodes, ion exchange is performed between the sample water and the pH adjusting solution, and the pH is reduced. The sample water is discharged to the outside in a state where it has risen to near neutrality.

  Similar to the calculation control unit 56 of the first embodiment, the calculation control unit 126 that controls the operation of the TOC meter and the calculation process of the TOC calculation also circulates in the measurement water flow path 118 of the measurement water when the sample is not measured. The liquid feed pump 123 is controlled so as to be stopped. If the measurement water is constantly circulated, the ion exchange membrane of the ion exchange unit 122 deteriorates. Therefore, by stopping the circulation of the measurement water when the measurement is interrupted, the progress of such deterioration is suppressed and the maintenance cost is reduced. Plan. However, when the circulation of the measurement water is stopped, the outside air diffuses into the measurement water flow path 118 from the outside as in the first embodiment, and the conductivity obtained by the conductivity measuring unit 124 changes, as shown in FIG. A similar phenomenon occurs. If measurement is started in such a state, the accuracy of the measurement result is impaired.

  Therefore, the arithmetic control unit 126 is configured to perform measurement after waiting until a predetermined waiting time elapses after the circulation of the measurement water is resumed. The method for setting the standby time is the same as the method of the first embodiment. The waiting time information holding unit 130 holds waiting time information measured in advance as corresponding to FIG. 2 of the first embodiment, and is measured by the information of the waiting time information holding unit 130 and the stop time measuring unit 128. The waiting time is set based on the stop time of the measured water circulation or the conductivity obtained by the conductivity measuring unit 124 immediately before the circulation of the measured water is resumed.

  In this embodiment, the stop time measuring unit 128 and the standby time information holding unit 130 are provided independently of the calculation control unit 126, but one of the stop time measuring unit 128 and the standby time information holding unit 130 or Both may be realized as one function of the arithmetic control unit 126.

14 6-port valve 16 Micro syringe 18 Sample injection mechanism (sample introduction part)
32 TC oxidation reaction unit 34 Sample injection unit 36 Combustion tube 38 Heating furnace 40 Gas purification / flow rate control unit 44 Dehumidification / gas treatment unit 46 Infrared gas analysis unit 48 Chemiluminescence analysis unit 56 Operation control unit 58 Stop time measurement unit 59 Standby time Information holding unit

Claims (7)

An oxidation reaction unit that oxidizes a measurement component in a sample water introduced with a combustion tube to convert it into an oxidizing gas, a sample introduction unit that introduces sample water into the oxidation reaction unit, and a measurement cell. A detection unit for measuring the concentration of the oxidizing gas therein, a carrier gas supply unit for sending a gas containing the oxidizing gas in the oxidation reaction unit to the detection unit by a carrier gas, and control of the sample introduction unit and the carrier gas supply unit In a water quality analyzer using a combustion-type oxidation method equipped with a controller for performing
Carrier gas supply stop time T until the oxidizing gas concentration in the carrier gas in the flow path from the carrier gas supply unit to the detection unit is saturated when the supply of the carrier gas in the carrier gas supply unit is stopped Alternatively, the carrier gas supply unit when the detection signal value S by the detection unit due to the carrier gas in the saturated state and the oxidizing gas concentration in the carrier gas in the flow path from the carrier gas supply unit to the detection unit are in a saturated state A standby time information holding unit which holds, as standby time information, a time t until the detection signal of the oxidizing gas in the detection unit disappears when the supply of the carrier gas is started by
When the supply of carrier gas is started at the start of measurement, the measured value T ′ of the carrier gas supply stop time in the carrier gas supply unit or the carrier gas detection signal value s by the detection unit, and the waiting time information holding unit Standby time information T or S held in the storage unit, and a calculation unit for calculating a standby time t ′ from the t to the introduction of the sample water,
The control unit stops carrier gas supply at the carrier gas supply unit when measurement is not being performed, starts carrier gas supply at the carrier gas supply unit at the start of measurement, and starts supplying carrier gas. A water quality analyzer configured to start introduction of sample water by the sample introduction unit after a waiting time t ′ calculated by the calculation unit has elapsed. An oxidation reaction part that oxidizes a carbon component as a measurement component in the introduced sample water by ultraviolet irradiation to convert it into carbon dioxide, a sample introduction part that introduces sample water into the oxidation reaction part, and a gas-liquid separation membrane An ion exchange unit and a carbon dioxide extraction unit for transferring carbon dioxide in the sample water to the measurement water by contacting the measurement water and the sample water that has passed through the oxidation reaction unit through the gas-liquid separation membrane. A measurement water supply unit that supplies deionized water from the exchange unit as measurement water to the carbon dioxide extraction unit, a detection unit that measures the conductivity of measurement water from the carbon dioxide extraction unit, the sample introduction unit, and the measurement water In a water quality analyzer using a wet oxidation method, including a control unit for controlling the supply unit,
Measurement water supply stop time T until the carbon dioxide concentration in the measurement water in the flow path from the measurement water supply unit to the detection unit becomes saturated when the supply of measurement water in the measurement water supply unit is stopped or Measurement by the measurement water supply unit when the detection signal value S by the detection unit and the carbon dioxide concentration in the measurement water in the flow path from the measurement water supply unit to the detection unit are saturated with the measurement water in the saturated state A standby time information holding unit that holds, as standby time information, a time t until the carbon dioxide detection signal from the detection unit disappears when water supply is started;
When the measurement water supply is started at the start of measurement, the measurement water supply stop time measurement value T ′ in the measurement water supply unit or the measurement water detection signal value s by the detection unit and the waiting time information holding unit Standby time information T or S held in the storage unit, and a calculation unit for calculating a standby time t ′ from the t to the introduction of the sample water,
The control unit stops the measurement water supply at the measurement water supply unit when measurement is not being performed, starts the measurement water supply at the measurement water supply unit at the start of measurement, and starts the supply of measurement water. A water quality analyzer configured to start introduction of sample water by the sample introduction unit after a waiting time t ′ calculated by the calculation unit has elapsed. The calculation unit uses the measured value T ′ of the carrier gas supply stop time or the measured water supply stop time,
If T '<T,
t ′ = t × T ′ / T,
If T ′ ≧ T,
t '= t
The water quality analyzer according to claim 1 or 2, wherein the waiting time t 'is determined and set as follows. The waiting time information holding unit holds one or a plurality of reference times shorter than T and T as waiting time information, and waiting times corresponding to T and each reference time,
The calculation unit compares the measured value T ′ of the carrier gas supply stop time or the measured water supply stop time with T and the reference time held in the standby time information holding unit, and in the standby time information holding unit. The water quality analyzer according to claim 1 or 2, wherein the corresponding waiting time held is set as the waiting time t '. The calculation unit, at the start of measurement, the detection signal value s of the carrier gas by the detection unit when the supply of carrier gas is started or the detection signal value s of the measurement water by the detection unit when the supply of measurement water is started From the waiting time information S and t held in the waiting time information holding unit,
If s <S,
t ′ = t × s / S,
If s ≧ S,
t '= t
The water quality analyzer according to claim 1 or 2, wherein the waiting time t 'is determined and set as follows. The standby time information holding unit holds one or a plurality of reference signal levels smaller than S and S as standby time information, and standby times corresponding to S and each reference signal level,
The calculation unit, at the start of measurement, the detection signal value s of the carrier gas by the detection unit when the supply of carrier gas is started or the detection signal value s of the measurement water by the detection unit when the supply of measurement water is started And the detected signal value s is compared with S and the reference signal level held in the waiting time information holding unit, and the corresponding waiting time held in the waiting time information holding unit is set as the waiting time t ′. The water quality analyzer according to claim 1 or 2.   The water quality analyzer according to any one of claims 1 to 6, wherein the measurement component to be measured in the sample water is total organic carbon, and the water quality analyzer is a total organic carbon measurement device.

Images