JP7544265B2 - Water Quality Analyzers - Google Patents

Description

The present invention relates to a water quality analysis device.

2. Description of the Related Art Conventionally, water quality analyzers having both a fluorescence measurement function and a turbidity measurement function are known (for example, see Patent Document 1).
Patent Document 1 Patent No. 6436266

Problem to be solved

It is preferable to be able to easily calibrate water quality analysis equipment.

General Disclosure

In order to solve the above problems, a first aspect of the present invention provides a water quality analysis apparatus. The water quality analysis apparatus may perform a calibration operation using a calibration aqueous solution. The water quality analysis apparatus may measure the concentration of a substance to be measured in sample water. The water quality analysis apparatus may include a flow cell. The flow cell may allow the sample water and the calibration aqueous solution to flow. The water quality analysis apparatus may include a first switching unit. The first switching unit may switch between supplying sample water or the calibration aqueous solution to the flow cell.

The first switching part may be a three-way valve.

The water quality analysis device may include a degassing tank. The degassing tank may remove air bubbles from the sample water and supply it to the flow cell. The first switching unit may be located between the flow cell and the degassing tank in the flow path through which the sample water flows.

The first switching section may be provided below the flow cell in the height direction.

The first switching section may be located upstream of the flow cell in a flow path through which the sample water and the calibration aqueous solution flow.

The water quality analysis device may be provided with a calibration aqueous solution removal unit. The calibration aqueous solution removal unit may remove the calibration aqueous solution from the flow cell at the end of the calibration operation.

The water quality analysis device may include a second switching unit. The second switching unit may be provided downstream of the flow cell in the flow path through which the sample water and the calibration aqueous solution flow. The second switching unit may switch between circulating the sample water or the calibration aqueous solution and discharging the sample water or the calibration aqueous solution.

The calibration aqueous solution may be either a turbidity standard sample used in turbidity calibration or a fluorescence intensity standard sample used in concentration calibration. When the calibration aqueous solution is a turbidity standard sample, the second switching unit may circulate the calibration aqueous solution. When the calibration aqueous solution is a fluorescence intensity standard sample, the second switching unit may discharge the calibration aqueous solution.

The water quality analysis device may include a plurality of flow cells. The water quality analysis device may include a third switching unit. The third switching unit may be provided between two flow cells in a flow path through which the sample water and the calibration aqueous solution flow.

Note that the above summary of the invention does not list all of the features of the present invention. Subcombinations of these features may also be inventions.

1 is a diagram showing a water quality analysis device 100 according to an embodiment. 2 is a diagram showing the flow path 1 of the water quality analysis device 100 in detail. FIG. A diagram showing the first switching unit 40 when measuring the turbidity or concentration of a water sample 3 in the water quality analysis device 100. 1 is a diagram showing a first switching unit 40 when performing turbidity calibration or concentration calibration in the water quality analysis device 100. FIG. FIG. 2 is a diagram showing a water quality analysis device 200 according to another embodiment. A diagram showing the first switching unit 40 and the second switching unit 50 when measuring the turbidity or concentration of a water sample 3 in the water quality analysis device 200. 2 is a diagram showing a first switching unit 40 and a second switching unit 50 when performing concentration calibration in the water quality analysis device 200. FIG. 2 is a diagram showing a first switching unit 40 and a second switching unit 50 when performing turbidity calibration in the water quality analysis device 200. FIG. FIG. 3 is a diagram showing a water quality analysis device 300 according to another embodiment. FIG. 4 is a diagram showing a water quality analysis device 400 according to a comparative example. FIG. 2 is a diagram showing a comparison between the water quality analysis device 100 of the embodiment and the water quality analysis device 400 of the comparative example. FIG. 13 is a diagram showing an example of the relationship between turbidity and fluorescence intensity.

The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

In this specification, technical matters may be explained using orthogonal coordinate axes of the X-axis, Y-axis, and Z-axis. The orthogonal coordinate axes merely identify the relative positions of components and do not limit a specific direction. The +Z-axis direction and the -Z-axis direction are opposite directions. When the Z-axis direction is described without indicating positive or negative, it means a direction parallel to the +Z-axis and -Z-axis. The extension direction of the flow cell 2 is the Z-axis. The axes perpendicular to the extension direction of the flow cell 2 are the X-axis and Y-axis. In this specification, the direction of the Z-axis may be referred to as the height direction. The +Z-axis direction is the positive side of the height direction.

Figure 1 is a diagram showing a water quality analysis device 100 according to an embodiment. In this example, the water quality analysis device 100 comprises a flow path 1, a flow cell 2, a turbidity detection optical system 10, a fluorescence detection optical system 20, a turbidity detection signal processing unit 13, a fluorescence detection signal processing unit 23, and a control and calculation unit 30. The control and calculation unit 30 has an infrared light lighting circuit 31, an excitation light lighting circuit 32, a turbidity calculation unit 33, a fluorescence intensity correction unit 34, and a concentration calculation unit 35. The turbidity detection optical system 10 and the fluorescence detection optical system 20 are optical systems of the water quality analysis device 100.

Sample water 3 flows through flow path 1 (shown by dashed lines) and inside flow cell 2. Sample water 3 contains a substance to be measured. In this example, the substance to be measured is polycyclic aromatic hydrocarbons (hereinafter referred to as PAHs). Multiple flow cells 2 are provided in the turbidity detection optical system 10 and the fluorescence detection optical system 20, respectively. In FIG. 1, the flow cell 2 provided in the turbidity detection optical system 10 is referred to as flow cell 2-1. Also, in FIG. 1, the flow cell 2 provided in the fluorescence detection optical system 20 is referred to as flow cell 2-2. Flow cell 2-1 and flow cell 2-2 are arranged in series in flow path 1. In FIG. 1, sample water 3 is introduced and discharged in the direction of the arrow.

The water quality analyzer 100 measures the concentration of a substance to be measured in a water sample 3. Examples of the water sample 3 include water supply and sewage water, environmental water such as seawater, and wastewater. The water quality analyzer 100 may be installed on a ship. The water quality analyzer 100 is a water quality analyzer using a fluorescence detection method. When a fluorescent substance such as PAH is contained in the water sample 3, fluorescence L4 of a wavelength specific to the substance is generated when the water sample 3 is irradiated with ultraviolet light (excitation light L3). Since the fluorescence intensity is proportional to the concentration of the fluorescent substance contained therein, the concentration of the fluorescent substance can be measured with high accuracy. In this example, the water quality analyzer 100 measures the concentration of the substance to be measured from the fluorescence intensity from the water sample 3. The fluorescence intensity is measured in the fluorescence detection optical system 20. The fluorescence intensity signal s2 is output from the fluorescence detection signal processing unit 23. In this specification, the "intensity signal" may be simply expressed as "intensity".

When the sample water 3 contains suspended matter, the excitation light L3 and the fluorescence L4 may be attenuated due to the influence of light scattering and absorption from the suspended matter (particles). This phenomenon is called the inner filter effect. Due to the inner filter effect, the measurement accuracy of the fluorescence intensity may deteriorate in an environment where the concentration of suspended matter (hereinafter, turbidity) is high. Therefore, in order to improve the measurement accuracy of the fluorescence intensity, it is preferable to correct the fluorescence intensity by the turbidity of the sample water 3. In this example, the water quality analysis device 100 measures the turbidity of the sample water 3 together with the fluorescence intensity. The water quality analysis device 100 measures the turbidity of the sample water 3 from the intensity of the scattered light or transmitted light from the sample water 3. The intensity of the scattered light or transmitted light of the sample water 3 is measured in the turbidity detection optical system 10. The intensity signal s1 of the scattered light or transmitted light of the sample water 3 is output from the turbidity detection signal processing unit 13.

The infrared light lighting circuit 31 is connected to the turbidity detection light-emitting unit 11 of the turbidity detection optical system 10. The infrared light lighting circuit 31 is a circuit that controls the operation of the turbidity detection light-emitting unit 11. The excitation light lighting circuit 32 is connected to the fluorescence detection light-emitting unit 21 of the fluorescence detection optical system 20. The excitation light lighting circuit 32 is a circuit that controls the operation of the fluorescence detection light-emitting unit 21.

First, the measurement of the turbidity of the sample water 3 will be described. The turbidity detection optical system 10 has a turbidity detection light-emitting unit 11 and a turbidity detection light-receiving unit 12. The turbidity detection light-emitting unit 11 irradiates infrared light L1. The turbidity detection light-emitting unit 11 irradiates the infrared light L1 to the sample water 3 inside the flow cell 2-1. As an example, the turbidity detection light-emitting unit 11 is an LED (Light Emitting Diode) or a laser irradiation device.

By irradiating the sample water 3 inside the flow cell 2-1 with infrared light L1, scattered light or transmitted light (referred to as emitted light L2) is generated. Scattered light is generated by light scattering in the sample water 3. Transmitted light is light that is not absorbed by suspended matter in the sample water 3. The turbidity detection light receiving unit 12 receives the emitted light L2. The turbidity detection light receiving unit 12 converts the emitted light L2 into an electrical intensity signal. As an example, the turbidity detection light receiving unit 12 is a photodiode.

The turbidity detection signal processing unit 13 processes the intensity signal from the turbidity detection light receiving unit 12. The turbidity detection signal processing unit 13 may amplify the intensity signal from the turbidity detection light receiving unit 12. The turbidity detection signal processing unit 13 may remove noise from the intensity signal from the turbidity detection light receiving unit 12. The turbidity detection signal processing unit 13 processes the intensity signal from the turbidity detection light receiving unit 12 and outputs it as an intensity signal s1 of scattered light or transmitted light. The intensity signal s1 of scattered light or transmitted light may be an intensity signal corresponding to at least one of the intensity of scattered light and the intensity of transmitted light.

The turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3. The turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3 based on a signal from the turbidity detection signal processing unit 13. In other words, the turbidity calculation unit 33 calculates the turbidity D1 of the sample water 3 based on the scattered light or transmitted light intensity signal s1. The turbidity calculation unit 33 may calculate the turbidity D1 of the sample water 3 by multiplying the scattered light or transmitted light intensity signal s1 by the turbidity calibration coefficient calculated by turbidity calibration. The turbidity calculation unit 33 may output the turbidity D1 to an external device, etc.

When the turbidity is low, the intensity of the scattered light is proportional to the turbidity. On the other hand, when the turbidity is high, the scattered light is attenuated by the inner filter effect, making it difficult to measure the turbidity based on the intensity of the scattered light. The turbidity detection signal processing unit 13 may calculate the reference turbidity based on the intensity of the transmitted light, and determine whether to use the intensity of the scattered light or the intensity of the transmitted light in the turbidity measurement based on the reference turbidity. The reference turbidity is a provisionally calculated turbidity. The reference turbidity may be calculated based on the intensity of the scattered light. For example, when the reference turbidity is 0 to 40 FNU (when the turbidity is low), the turbidity is calculated based on the intensity of the scattered light. Also, when the reference turbidity is 40 to 400 FNU (when the turbidity is high), the reference turbidity is taken as the turbidity. Note that FNU is one of the units of turbidity. FNU is a formazin turbidity unit. Furthermore, the control and calculation unit 30 may calculate a reference turbidity based on the intensity of transmitted light, and determine whether to use the intensity of scattered light or the intensity of transmitted light in turbidity measurement based on the reference turbidity.

The turbidity detection signal processing unit 13 may also output a scattered light or transmitted light intensity signal s1 using both the scattered light intensity and the transmitted light intensity. For example, the scattered light or transmitted light intensity signal s1 may be the ratio of the scattered light intensity to the transmitted light intensity (scattered light intensity/transmitted light intensity). By setting the scattered light or transmitted light intensity signal s1 to the ratio of the scattered light intensity to the transmitted light intensity, the error in the scattered light intensity and the error in the transmitted light intensity can be offset. When the reference turbidity is 0 to 400 FNU, the turbidity detection signal processing unit 13 may output the ratio of the scattered light intensity to the transmitted light intensity as the scattered light or transmitted light intensity signal s1. The turbidity detection signal processing unit 13 may also output the scattered light intensity and the transmitted light intensity, and the control and calculation unit 30 may calculate the ratio of the scattered light intensity to the transmitted light intensity.

Next, the measurement of the fluorescence intensity of the sample water 3 will be described. The fluorescence detection optical system 20 has a fluorescence detection light-emitting unit 21 and a fluorescence detection light-receiving unit 22. The fluorescence detection light-emitting unit 21 irradiates excitation light L3. The fluorescence detection light-emitting unit 21 irradiates the excitation light L3 to the sample water 3 inside the flow cell 2-2. The excitation light L3 is, for example, ultraviolet light. The fluorescence detection light-emitting unit 21 may include an ultraviolet light source therein. The ultraviolet light source is, for example, a xenon flash lamp. The ultraviolet light source may be an LED or a laser irradiation device.

The fluorescence detection light-emitting unit 21 may include an optical filter inside. By including an optical filter, the fluorescence detection light-emitting unit 21 can irradiate the flow cell 2-2 with light in a predetermined wavelength range of the excitation light L3. In this example, the substance to be measured is PAH. PAH emits fluorescence most efficiently when the wavelength of the excitation light is around 250 nm. Therefore, the transmission wavelength of the optical filter inside the fluorescence detection light-emitting unit 21 is set to, for example, 200 nm or more and 300 nm or less.

Fluorescence L4 is generated by irradiating the sample water 3 inside the flow cell 2-2 with excitation light L3. The fluorescence detection light receiving unit 22 receives the fluorescence L4. The fluorescence detection light receiving unit 22 converts the fluorescence L4 into a fluorescence intensity signal. As an example, the fluorescence detection light receiving unit 22 is a photodiode.

The fluorescence detection light receiving unit 22 may include an optical filter therein. Because it includes an optical filter, the fluorescence detection light receiving unit 22 can receive light in a predetermined wavelength range of the fluorescence L4. In this example, the substance to be measured is PAH. When the wavelength of the excitation light for PAH is around 250 nm, the fluorescence wavelength is around 350 nm. Therefore, the transmission wavelength of the optical filter inside the fluorescence detection light receiving unit 22 is set to, as an example, 300 nm or more and 400 nm or less.

The fluorescence detection signal processing unit 23 processes the fluorescence intensity signal from the fluorescence detection light receiving unit 22. The fluorescence detection signal processing unit 23 may amplify the signal from the fluorescence detection light receiving unit 22. The fluorescence detection signal processing unit 23 may remove noise from the signal from the fluorescence detection light receiving unit 22. The fluorescence detection signal processing unit 23 processes the fluorescence intensity signal from the fluorescence detection light receiving unit 22 and outputs it as a fluorescence intensity signal s2.

The fluorescence intensity correction unit 34 corrects the fluorescence intensity. The fluorescence intensity correction unit 34 corrects the fluorescence intensity signal s2 from the fluorescence detection signal processing unit 23 based on the turbidity D1 of the sample water 3. For example, since the higher the turbidity D1 of the sample water 3, the lower the fluorescence intensity, the fluorescence intensity signal s2 is multiplied by a correction coefficient that increases as the turbidity D1 of the sample water 3 increases to calculate the fluorescence intensity signal s3 (see Figure 12). It is preferable to obtain the correction coefficient in advance.

The concentration calculation unit 35 calculates the concentration C1. The concentration calculation unit 35 calculates the concentration C1 based on the fluorescence intensity signal s3. In this example, the concentration calculation unit 35 calculates the concentration C1 based on the fluorescence intensity signal s3 corrected by the fluorescence intensity correction unit 34. The concentration calculation unit 35 may calculate the concentration C1 by multiplying the fluorescence intensity signal s3 by a concentration calibration coefficient calculated by concentration calibration. The concentration calculation unit 35 may output the concentration C1 to an external device, etc.

The water quality analysis device 100 performs calibration work using a calibration aqueous solution. In this example, the calibration work is turbidity calibration and concentration calibration. The calibration aqueous solution is the aqueous solution used in the calibration work. The calibration aqueous solution may flow inside the flow path 1 and the flow cell 2. The calibration aqueous solution used in the turbidity calibration and the calibration aqueous solution used in the concentration calibration may be different. The calibration aqueous solution may be either a turbidity standard sample used in the turbidity calibration or a fluorescence intensity standard sample used in the concentration calibration.

Turbidity calibration will be described. In this specification, in order to calculate the turbidity D1 of the sample water 3, the turbidity calculation unit 33 sets a turbidity calibration coefficient b1. The turbidity calibration coefficient b1 converts the intensity signal s1 of the scattered light or transmitted light from the sample water 3 into the turbidity D1 of the sample water 3. The following formula 1 holds for the turbidity calibration coefficient b1. In formula 1, the offset is e1. The offset e1 may be a fixed constant. The offset e1 may be 0. The turbidity calibration coefficient b1 may be a fixed coefficient. The turbidity calibration coefficient b1 may be a variable. The turbidity calibration coefficient b1 may be a variable that changes depending on the intensity signal s1. When the turbidity calibration coefficient b1 is a variable, calibration is performed using a plurality of turbidity standard samples having different turbidities. Moreover, the turbidity calculation unit 33 may set a function f that holds that the turbidity D1 of the sample water 3 = f (intensity signal s1) holds, instead of the turbidity calibration coefficient b1. In this case, calibration is also performed using turbidity standard samples having different turbidities.
(Equation 1)
D1=b1×s1+e1

A turbidity standard sample is used in turbidity calibration. A turbidity standard sample is a sample that serves as a reference for turbidity measurement and is an example of a calibration aqueous solution. The turbidity of a turbidity standard sample is known. Therefore, in turbidity calibration, the turbidity calibration coefficient b1 can be calculated from equation 1 by measuring the intensity signal of the turbidity standard sample. Formazin, kaolin, and polystyrene are generally used as turbidity standard samples. Formazin is a mixed aqueous solution prepared by polymerizing and adjusting hydrazinium sulfate and hexamethylenetetramine. Kaolin is an aqueous solution prepared by purifying and adjusting kaolinite particles. Polystyrene is a polystyrene-based particle suspension.

Concentration calibration will be described. In this specification, in order to calculate the concentration C1, the concentration calculation unit 35 sets a concentration calibration coefficient b2. The concentration calibration coefficient b2 converts the fluorescence intensity of the measurement target substance into the concentration C1 of the measurement target substance. The concentration calibration coefficient b2 satisfies the following formula 2. In formula 2, the offset is e2. The offset e2 may be a fixed constant. The offset e2 may be 0. The concentration calibration coefficient b2 may be a fixed coefficient. The concentration calibration coefficient b2 may be a variable. The concentration calibration coefficient b2 may be a variable that changes depending on the fluorescence intensity signal s3. When the concentration calibration coefficient b2 is a variable, the calibration is performed using the fluorescence intensity standard sample concentrations having a plurality of different concentrations. In addition, the concentration calculation unit 35 may set a function g where concentration C1 = g (fluorescence intensity signal s3) holds true instead of the concentration calibration coefficient b2. In this case, the calibration is also performed using the fluorescence intensity standard sample concentrations having a plurality of different concentrations.
(Equation 2)
C1=b2×s3+e2

In the calibration of fluorescence intensity (concentration calibration), a fluorescence intensity standard sample is used. A fluorescence intensity standard sample is a sample that serves as a reference for concentration measurement, and is an example of a calibration aqueous solution. The fluorescence intensity standard sample has a known concentration. Therefore, in the calibration of fluorescence intensity, the concentration calibration coefficient b2 can be calculated from equation 2 by measuring the fluorescence intensity of the fluorescence intensity standard sample. If the turbidity of the fluorescence intensity standard sample is known, the fluorescence intensity may be corrected by the turbidity of the standard sample to calculate the concentration calibration coefficient b2. The fluorescence intensity standard sample differs for each substance to be measured. In this example, since the substance to be measured is PAH, for example, a fluorescence intensity standard sample containing phenanthrene or amines is used. The fluorescence intensity standard sample may also be PAH.

In a water quality analysis device 100 in which the turbidity calibration coefficient b1 is not set, turbidity calibration is performed before concentration measurement. In a water quality analysis device 100 in which the concentration calibration coefficient b2 is not set, concentration calibration is performed before concentration measurement. Furthermore, the turbidity calibration coefficient b1 and the concentration calibration coefficient b2 may change due to dirt inside the flow cell 2 through which the sample water 3 flows and deterioration of the optical components over time. In order to correct for the effects of dirt inside the flow cell 2 through which the sample water 3 flows and deterioration of the optical components over time, it is preferable that the turbidity calibration coefficient b1 and the concentration calibration coefficient b2 are updated periodically.

Figure 2 is a detailed diagram of the flow path 1 of the water quality analysis device 100. The water quality analysis device 100 is equipped with a first switching unit 40 in the flow path 1. Note that in Figure 2, the X-axis, Y-axis, and Z-axis are shown as orthogonal coordinate axes. The flow cell 2 extends in the Z-axis direction (height direction). The flow cell 2 extends in a direction perpendicular to the XY plane.

The water quality analysis device 100 in this example has both a fluorescence measurement function and a turbidity measurement function. Therefore, turbidity calibration and fluorescence intensity calibration (concentration calibration) are each performed in the water quality analysis device 100. At this time, a quantity of calibration aqueous solution must be prepared to circulate through all of the flow paths 1 in the water quality analysis device 100. Therefore, when performing calibration on a ship, etc., a volume for storing multiple calibration aqueous solutions must be secured in addition to the water quality analyzer.

In this example, the first switching unit 40 switches between supplying sample water 3 or calibration aqueous solution to the flow cell 2-1 (and flow cell 2-2). In other words, the first switching unit 40 switches the flow path 1 upstream of the flow cell 2. Therefore, by providing the water quality analysis device 100 with the first switching unit 40, it is possible to easily switch between the flow path 1 for the sample water 3 and the flow path 1 for the calibration aqueous solution. Therefore, it is possible to reduce the amount of calibration aqueous solution used.

The first switching unit 40 is provided upstream of the flow cell 2 in the flow path 1 through which the sample water 3 and the calibration aqueous solution flow. In this example, the first switching unit 40 is provided upstream of the flow cells 2-1 and 2-2. By providing the first switching unit 40 upstream of the flow cells 2-1 and 2-2, turbidity calibration and concentration calibration can be easily performed.

In this example, the first switching unit 40 is a three-way valve. The first switching unit 40 has an adjusting valve 42 and an adjusting valve 44. The adjusting valve 42 opens and closes the flow path 1 for the sample water 3. The adjusting valve 44 opens and closes the flow path 1 for the calibration aqueous solution. In Figure 2, the adjusting valves 42 and 44 are open. In the figure, when the adjusting valves 42 and 44 are open, the adjusting valves are shown in white, and when the adjusting valves 42 and 44 are closed, the adjusting valves are shown in black.

In this example, the direction in which the sample water 3 and the calibration aqueous solution flow within the flow path 1 is from the -Z axis toward the +Z axis. In other words, the direction in which the sample water 3 and the calibration aqueous solution flow is from the negative height side toward the positive height side. Because the sample water 3 and the calibration aqueous solution flow from the negative height side toward the positive height side, it is preferable that the sample water 3 and the calibration aqueous solution flow under pressure. The first switching unit 40 may be provided below the flow cell 2 in the height direction.

Figure 3 is a diagram showing the first switching unit 40 when measuring the turbidity or concentration of the sample water 3 in the water quality analysis device 100. When measuring the turbidity or concentration of the sample water 3, the adjustment valve 42 is open and the adjustment valve 44 is closed. Therefore, the sample water 3 flows into the flow cell 2.

The sample water 3 is supplied from a degassing tank 90. The degassing tank 90 may remove air bubbles from the sample water 3. The degassing tank 90 may be of an open-to-atmosphere type. The degassing tank 90 may be of a pressurized type. The degassing tank 90 may be of a swirling flow type. The degassing tank 90 may remove air bubbles from the sample water 3 by a known method.

In this example, the first switching unit 40 is provided between the flow cell 2 and the degassing tank 90 in the flow path 1 through which the sample water 3 flows. In FIG. 3, the first switching unit 40 is provided between the flow cell 2-1 and the degassing tank 90 in the flow path 1 through which the sample water 3 flows. By providing the first switching unit 40 between the flow cell 2 and the degassing tank 90 in the flow path 1 through which the sample water 3 flows, the calibration work can be performed without circulating the calibration aqueous solution through the degassing tank 90. Therefore, it is possible to reduce the amount of calibration aqueous solution used.

Figure 4 is a diagram showing the first switching unit 40 when performing turbidity calibration or concentration calibration in the water quality analysis device 100. When performing turbidity calibration or concentration calibration, the adjustment valve 42 is closed and the adjustment valve 44 is open. Therefore, the calibration aqueous solution 4 is supplied to the flow cell 2.

The calibration aqueous solution 4 is supplied from a syringe 70. The syringe 70 may supply the calibration aqueous solution 4 to the flow cell 2 at the start of the calibration work. The syringe 70 may function as a calibration aqueous solution supply unit. The syringe 70 may remove the calibration aqueous solution 4 from the flow cell 2 at the end of the calibration work. The syringe 70 is an example of a calibration aqueous solution removal unit. The syringe 70 may be operated by a device or machine, or may be operated manually. Also, instead of the syringe 70, a device that functions as the calibration aqueous solution supply unit and the calibration aqueous solution removal unit may be provided. By providing the water quality analysis device 100 with the first switching unit 40, the calibration aqueous solution 4 can be supplied by the syringe 70 or the like, making it possible to reduce the amount of calibration aqueous solution 4 used.

Also, in this example, while the calibration aqueous solution 4 is being supplied to the flow cell 2, the calibration aqueous solution does not need to flow in the flow path 1. In other words, the calibration aqueous solution 4 may be stationary at a constant height in the flow path 1. The calibration aqueous solution 4 can be made stationary by continuing to push the syringe 70. In the case of turbidity calibration, the calibration aqueous solution 4 (turbidity standard sample) may be stationary so as to fill the flow cell 2-1. In the case of concentration calibration, the calibration aqueous solution 4 (fluorescence intensity standard sample) may be stationary so as to fill the flow cell 2-2. Because the calibration aqueous solution does not flow in the flow path 1 during the calibration operation, it is possible to reduce the amount of calibration aqueous solution 4 used.

Figure 5 is a diagram showing a water quality analysis device 200 according to another embodiment. In Figure 5, flow path 1 of the water quality analysis device 200 is shown in detail. The water quality analysis device 200 of Figure 5 differs from the water quality analysis device 100 of Figure 2 in that it is provided with a second switching unit 50 in flow path 1. Other configurations of the water quality analysis device 200 of Figure 5 may be the same as those of the water quality analysis device 100 of Figure 2.

In this example, the second switching unit 50 switches between circulating the sample water 3 or the calibration aqueous solution 4 and discharging the sample water 3 or the calibration aqueous solution 4. In other words, the second switching unit 50 switches the flow path 1 downstream of the flow cell 2. Therefore, by providing the water quality analysis device 200 with the second switching unit 50, the circulation and discharge of the sample water 3 or the calibration aqueous solution 4 can be easily switched.

The second switching unit 50 is provided downstream of the flow cell 2 in the flow path 1 through which the sample water 3 and the calibration aqueous solution 4 flow. In this example, the second switching unit 50 is provided downstream of the flow cells 2-1 and 2-2.

In this example, the second switching unit 50 is a three-way valve. The second switching unit 50 has an adjusting valve 52 and an adjusting valve 54. The adjusting valve 52 opens and closes the discharge flow path 1. The adjusting valve 54 opens and closes the circulation flow path 1. In Figure 5, the adjusting valves 52 and 54 are open. When the adjusting valves 52 and 54 are open in the figure, the adjusting valves are shown in white, and when the adjusting valves 52 and 54 are closed, the adjusting valves are shown in black.

Figure 6 is a diagram showing the first switching unit 40 and the second switching unit 50 when measuring the turbidity or concentration of the sample water 3 in the water quality analysis device 200. When measuring the turbidity or concentration of the sample water 3, the adjustment valves 42 and 52 are open, and the adjustment valves 44 and 54 are closed. Therefore, the sample water 3 flows into the flow cell 2.

In this example, the adjustment valve 52 is opened to drain the sample water 3. When measuring the fluorescence intensity of the sample water 3, the sample water 3 is easily deteriorated because the excitation light L3 is irradiated onto the sample water 3. Therefore, it is preferable to drain the sample water 3 rather than circulate it.

Figure 7 is a diagram showing the first switching unit 40 and the second switching unit 50 when performing concentration calibration in the water quality analysis device 200. When performing concentration calibration, the adjustment valves 44 and 52 are open, and the adjustment valves 42 and 54 are closed. The calibration aqueous solution 4 flows through the flow cell 2. In this example, the calibration aqueous solution 4 is a fluorescence intensity standard sample. The water quality analysis device 200 may also be equipped with a device 80 when performing concentration calibration. The device 80 may be an external device.

In this example, the adjustment valve 52 is opened to drain the calibration aqueous solution 4. That is, when the calibration aqueous solution 4 is a fluorescence intensity standard sample, the second switching unit 50 drains the calibration aqueous solution 4. During concentration calibration, the sample water 3 is irradiated with excitation light L3, which makes the calibration aqueous solution 4 prone to deterioration. Therefore, it is preferable to drain the calibration aqueous solution 4 rather than circulate it. When the calibration aqueous solution 4 is a fluorescence intensity standard sample, the calibration work can be performed with high accuracy by draining the calibration aqueous solution 4.

The device 80 may supply the calibration aqueous solution 4 to the adjustment valve 44 of the first switching unit 40. In this example, the supply device 80 continues to supply the calibration aqueous solution 4. Therefore, unlike FIG. 4, the calibration aqueous solution 4 flows through the flow cell 2 during the calibration operation.

Figure 8 is a diagram showing the first switching unit 40 and the second switching unit 50 when performing turbidity calibration in the water quality analysis device 200. When performing turbidity calibration, the adjustment valves 44 and 54 are open, and the adjustment valves 42 and 52 are closed. The calibration aqueous solution 4 flows through the flow cell 2. In this example, the calibration aqueous solution 4 is a turbidity standard sample. The water quality analysis device 200 may also be equipped with a device 80 when performing turbidity calibration. The device 80 may be an external device.

In this example, the adjustment valve 54 is opened to circulate the calibration aqueous solution 4. That is, when the calibration aqueous solution 4 is a turbidity standard sample, the second switching unit 50 circulates the calibration aqueous solution 4. The calibration aqueous solution 4 that has passed through the adjustment valve 54 of the second switching unit 50 may return to the adjustment valve 44 of the first switching unit 40. The turbidity standard sample is not easily deteriorated during turbidity calibration. Therefore, it is preferable to circulate the calibration aqueous solution 4 in order to reduce the amount of calibration aqueous solution 4 used.

When the calibration aqueous solution 4 is circulated, the current calibration result may be corrected based on the past calibration history. For example, the current calibration result is corrected based on the irradiation history of the infrared light L1 and the excitation light L3. The irradiation history of the infrared light L1 and the excitation light L3 refers to the irradiation time and irradiation intensity of the infrared light L1 and the excitation light L3. If the irradiation time of the infrared light L1 and the excitation light L3 is long, the deterioration of the calibration aqueous solution 4 will be accelerated. Also, if the irradiation intensity of the infrared light L1 and the excitation light L3 is high, the deterioration of the calibration aqueous solution 4 will be accelerated. By correcting the current calibration result based on the past calibration history, the influence of the deterioration of the calibration aqueous solution 4 can be reduced and the calibration work can be performed more accurately. It is preferable to obtain in advance the relationship between the irradiation history of the infrared light L1 and the excitation light L3 and the deterioration of the calibration aqueous solution 4.

The device 80 may supply the calibration aqueous solution 4 to the adjustment valve 44 of the first switching unit 40. The calibration aqueous solution 4 that has passed through the adjustment valve 54 of the second switching unit 50 may return to the device 80. The device 80 may supply the calibration aqueous solution 4 again to the adjustment valve 44 of the first switching unit 40. In this example, the device 80 continues to circulate the calibration aqueous solution 4. Therefore, unlike FIG. 4, the calibration aqueous solution 4 flows through the flow cell 2 during the calibration operation.

Figure 9 is a diagram showing a water quality analysis device 300 according to another embodiment. In Figure 9, flow path 1 of the water quality analysis device 300 is shown in detail. The water quality analysis device 300 of Figure 9 differs from the water quality analysis device 100 of Figure 2 in that it is provided with a third switching unit 60 in flow path 1. Other configurations of the water quality analysis device 300 of Figure 9 may be the same as those of the water quality analysis device 100 of Figure 2.

In this example, the third switching unit 60 switches between supplying the sample water 3 or the calibration aqueous solution 4 to the flow cell 2-2. In other words, the third switching unit 60 switches the flow path 1 between the flow cell 2-1 and the flow cell 2-2. Therefore, by providing the water quality analysis device 100 with the third switching unit 60, it is possible to easily switch between the flow path 1 for the sample water 3 and the flow path 1 for the calibration aqueous solution between the flow cell 2-1 and the flow cell 2-2. When calibrating (concentration calibrating) only the flow cell 2-2, it is possible to reduce the amount of calibration aqueous solution 4 used.

The third switching unit 60 is provided downstream of the flow cell 2-1 in the flow path 1 through which the sample water 3 and the calibration aqueous solution 4 flow. The third switching unit 60 is also provided upstream of the flow cell 2-2 in the flow path 1 through which the sample water 3 and the calibration aqueous solution 4 flow. The third switching unit 60 is provided between the two flow cells 2 in the flow path 1 through which the sample water 3 and the calibration aqueous solution 4 flow.

In this example, the third switching unit 60 is a three-way valve. The third switching unit 60 has an adjustment valve 62 and an adjustment valve 64. The adjustment valve 62 opens and closes the flow path 1 for the sample water 3. The adjustment valve 64 opens and closes the flow path 1 for the calibration aqueous solution.

Figure 10 is a diagram showing a water quality analysis device 400 according to a comparative example. Figure 10 shows in detail the flow path 1 of the water quality analysis device 400 when measuring the turbidity or concentration of the sample water 3. The water quality analysis device 400 of Figure 10 differs from the water quality analysis device 100 of Figure 3 in that it does not have a first switching unit 40. Other configurations of the water quality analysis device 400 of Figure 10 may be the same as those of the water quality analysis device 100 of Figure 3.

Figure 11 is a diagram showing a comparison between the water quality analysis device 100 of the embodiment and the water quality analysis device 400 of the comparative example. In estimating the amount of calibration aqueous solution to be used, the flow path diameter of flow path 1 was set to φ8 mm, the total flow path length of the water quality analysis device was set to 400 cm, the optical system flow path length was set to 40 cm, and the degassing tank capacity of the degassing tank 90 was set to 2000 mL. The optical system flow path length is the flow path length of the flow path provided in the optical system of the water quality analysis device. The optical system flow path length is, in other words, the flow path length from the flow path 1 provided in the turbidity detection optical system 10 to the flow path 1 provided in the fluorescence detection optical system 20.

In the water quality analysis device 400, the calibration work is performed with all flow paths and the degassing tank 90 in the water quality analysis device 400 filled with the calibration aqueous solution 4. Therefore, the amount of the calibration aqueous solution used in the calibration work is large, and the amount of the calibration aqueous solution is 2201 ml.

On the other hand, the water quality analysis device 100 is provided with a first switching unit 40, which blocks the flow path 1 from the degassing tank 90. Therefore, the calibration work can be performed with only the flow path 1 provided near the optical system filled with the calibration aqueous solution 4. In this case, the calibration aqueous solution 4 is not filled in all the flow paths of the water quality analysis device 100 except for the optical system flow path and the degassing tank 90, so the amount of the calibration aqueous solution can be reduced to 20.1 ml. The amount of the calibration aqueous solution of the water quality analysis device 100 during the calibration work may be 100 ml or less. The amount of the calibration aqueous solution of the water quality analysis device 100 is less than 1% compared to the amount of the calibration aqueous solution of the water quality analysis device 400. Therefore, the volume for storing the calibration aqueous solution 4 can be reduced, and the calibration work can be performed easily.

Figure 12 shows an example of the relationship between turbidity and fluorescence intensity. In Figure 12, the solid line shows the ideal value, and the dotted line shows the measured value.

As shown in Figure 12, due to the inner filter effect, the difference between the ideal and measured values of fluorescence intensity increases as the turbidity increases. Therefore, it is preferable for the fluorescence intensity correction unit 34 to correct the fluorescence intensity so that it approaches the ideal value. In the example of Figure 12, the fluorescence intensity correction unit 34 corrects the fluorescence intensity by multiplying the fluorescence intensity by a correction coefficient that increases as the turbidity increases. As an example, the correction coefficient is expressed as ideal fluorescence intensity / measured fluorescence intensity.

Although the present invention has been described above using an embodiment, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiment. It is clear from the claims that forms incorporating such modifications or improvements can also be included in the technical scope of the present invention.

It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before,""priorto," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first,""next," etc. for convenience, it does not mean that it is essential to perform the process in this order.
[Item 1]
A water quality analyzer that performs a calibration operation using a calibration aqueous solution and measures the concentration of a target substance in sample water,
a flow cell through which the sample water and the calibration aqueous solution flow;
a first switching unit that switches between supplying the sample water and supplying the calibration aqueous solution to the flow cell;
A water quality analysis device comprising:
[Item 2]
2. The water quality analysis device according to claim 1, wherein the first switching unit is a three-way valve.
[Item 3]
a degassing tank for removing air bubbles from the sample water and supplying the sample water to the flow cell;
the first switching unit is located between the flow cell and the degassing tank in a flow path through which the sample water flows;
3. The water quality analysis device according to item 1 or 2.
[Item 4]
4. The water quality analysis device according to claim 1, wherein the first switching unit is provided below the flow cell in the height direction.
[Item 5]
5. The water quality analysis device according to claim 1, wherein the first switching unit is provided upstream of the flow cell in a flow path through which the sample water and the calibration aqueous solution flow.
[Item 6]
6. The water quality analyzer according to claim 1, further comprising a calibration aqueous solution removal unit that removes the calibration aqueous solution from the flow cell when the calibration procedure is completed.
[Item 7]
The water quality analysis device described in item 5 further comprises a second switching unit that is provided downstream of the flow cell in a flow path through which the sample water and the calibration aqueous solution flow, and that switches between circulating the sample water or the calibration aqueous solution and discharging the sample water or the calibration aqueous solution.
[Item 8]
the calibration aqueous solution is either a turbidity standard sample used for turbidity calibration or a fluorescence intensity standard sample used for concentration calibration,
When the calibration aqueous solution is the turbidity standard sample, the second switching unit circulates the calibration aqueous solution,
When the calibration aqueous solution is the fluorescence intensity standard sample, the second switching unit discharges the calibration aqueous solution.
8. The water quality analysis device according to item 7.
[Item 9]
A plurality of the flow cells are provided,
a third switching unit provided between the two flow cells in a flow path through which the sample water and the calibration aqueous solution flow;
6. The water quality analysis device according to any one of items 1 to 5.

1: Flow path, 2: Flow cell, 3: Sample water, 4: Calibration aqueous solution, 10: Turbidity detection optical system, 11: Light emitter for turbidity detection, 12: Light receiver for turbidity detection, 13: Signal processing unit for turbidity detection, 20: Fluorescence detection optical system, 21: Light emitter for fluorescence detection, 22: Light receiver for fluorescence detection, 23: Signal processing unit for fluorescence detection, 30: Control calculation unit, 31: Infrared light lighting circuit, 32: Excitation light lighting circuit, 33: Turbidity Calculation unit, 34... fluorescence intensity correction unit, 35... concentration calculation unit, 40... first switching unit, 42... regulating valve, 44... regulating valve, 50... second switching unit, 52... regulating valve, 54... regulating valve, 60... third switching unit, 62... regulating valve, 64... regulating valve, 70... syringe, 80... apparatus, 90... degassing tank, 100... water quality analysis apparatus, 200... water quality analysis apparatus, 300... water quality analysis apparatus, 400... water quality analysis apparatus

Claims (8)

A water quality analyzer that performs a calibration operation using a calibration aqueous solution and measures the concentration of a target substance in sample water,
a flow cell through which the sample water and the calibration aqueous solution flow;
a syringe for supplying the calibration aqueous solution;
a first switching unit that switches between supplying the sample water or supplying the calibration aqueous solution supplied from the syringe to the flow cell ,
the flow cell is provided in a flow path through which the sample water and the calibration aqueous solution flow;
when the first switching unit is switched so that the calibration aqueous solution is supplied to the flow cell and the calibration operation is performed, the syringe is continuously pressed, so that the syringe stops the calibration aqueous solution at a constant height in the flow path.
Water quality analysis equipment. A water quality analyzer that performs a calibration operation using a calibration aqueous solution and measures the concentration of a target substance in sample water,
a flow cell through which the sample water and the calibration aqueous solution flow;
a calibration aqueous solution supply unit for supplying the calibration aqueous solution;
a first switching unit that switches between supplying the sample water or supplying the calibration aqueous solution supplied by the calibration aqueous solution supply unit to the flow cell;
Equipped with
the flow cell is provided in a flow path through which the sample water and the calibration aqueous solution flow;
When the first switching unit is switched so that the calibration aqueous solution is supplied to the flow cell and the calibration operation is performed, the calibration aqueous solution supply unit stops the calibration aqueous solution at a constant height in the flow path,
After performing the calibration operation, the calibration aqueous solution supplying unit removes the calibration aqueous solution in the flow path through the first switching unit. A water quality analyzer that performs a calibration operation using a calibration aqueous solution and measures the concentration of a target substance in sample water,
a flow cell through which the sample water and the calibration aqueous solution flow;
a first switching unit that is provided upstream of the flow cell in a flow path through which the sample water and the calibration aqueous solution flow, and that switches between supplying the sample water or the calibration aqueous solution to the flow cell;
a second switching unit that is provided downstream of the flow cell in the flow path and that switches between circulating the sample water or the calibration aqueous solution and discharging the sample water or the calibration aqueous solution;
Equipped with
the calibration aqueous solution is either a turbidity standard sample used for turbidity calibration or a fluorescence intensity standard sample used for concentration calibration,
When the calibration aqueous solution is the turbidity standard sample, the second switching unit circulates the calibration aqueous solution,
When the calibration aqueous solution is the fluorescence intensity standard sample, the second switching unit discharges the calibration aqueous solution. The water quality analyzer according to claim 3 , further comprising a calibration aqueous solution removal unit that removes the calibration aqueous solution from the flow cell when the calibration operation is completed. The water quality analyzer according to claim 1 , wherein the first switching unit is a three - way valve. a degassing tank for removing air bubbles from the sample water and supplying the sample water to the flow cell;
The water quality analyzer according to claim 1 , wherein the first switching unit is located between the flow cell and the degassing tank in a flow path through which the sample water flows. The water quality analyzer according to claim 1 , wherein the first switching unit is provided below the flow cell in a height direction. The water quality analyzer according to claim 1 , wherein the first switching unit is provided upstream of the flow cell in a flow path through which the sample water and the calibration aqueous solution flow.

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