Water quality analyzer

Abstract

The invention provides a water quality analyzer with which an abnormality in the collection of water can be determined by detecting whether or not a predetermined amount of a liquid sample has been fed into a sample container. The analyzer is formed of: a sample container 53 into which a liquid sample can be introduced through a liquid sample introduction port 53e formed in a lower portion of the container 53; a light source unit 51 for irradiating the container 53 with light; and a detection unit 52 for detecting light that has passed through the container 53, and further includes a determination unit for determining whether or not a predetermined amount of the liquid sample has been contained in the container 53 on the basis of the change in the light intensity detected by the detection unit 52 when the liquid sample is fed into the container 53.

Claims

1. A water quality analyzer, comprising: a sample container including a liquid sample introduction port formed in its lower portion, the sample container configured to receive a predetermined amount of liquid sample introduced through the liquid sample introduction port; a light source for irradiating the sample container with light; a detector for detecting light passing through the sample container, wherein a reference change, in light intensity is detected by the detector when the predetermined amount of liquid sample is introduced into the sample container; a first valve and a second valve connected to each other to introduce the predetermined amount of liquid sample into the sample container; the first valve connected to the liquid sample introduction port; the second valve connected to a syringe pump; a memory storing the reference change in light intensity; and a processor comprising program code configured to; determine whether or not the predetermined amount of liquid sample is contained in the sample container based on an actual change in light intensity detected by the detector when the sample liquid is stored in the sample container, and by comparing the detected actual change in light intensity with the reference change in light intensity; and wherein the program code further comprises; weighing code configured to cause the processor to control the syringe pump to weigh and collect the predetermined amount of liquid sample before introduction into the sample container; and control code configured to cause the processor to control the weighing code and the first and second valves.

2. The water quality analyzer according to claim 1, wherein the sample container is a measuring cell for analyzing the liquid sample or a reaction container for causing a reaction in the liquid sample.

3. The water quality analyzer according to claim 1, wherein a position of a target region to be measured by the light source and the detector is arranged above the liquid sample introduction port.

4. The water quality analyzer according to claim 1, wherein the water quality analyzer further comprises a display configured to display an amount of liquid fed into the sample container and display a message based on a change of light intensity of the light passing through the sample container.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram showing the entire configuration of an example of the total nitrogen measuring device according to the present invention;

(2) FIG. 2 is a cross-sectional diagram showing an example of the configuration of the reactor;

(3) FIG. 3 is a cross-sectional diagram showing an example of the configuration of the measuring unit;

(4) FIG. 4 is a schematic diagram showing the entire configuration of an example of a conventional total nitrogen measuring device; and

(5) FIG. 5 is a graph showing an example of a change in the light intensity.

DETAILED DESCRIPTION OF EMBODIMENTS

(6) In the following, the embodiments of the present invention are described in reference to the drawings. Here, the present invention is not limited to the embodiments as described below, and needless to say, includes various modifications as long as the gist of the present invention is not deviated from.

(7) FIG. 1 is a schematic diagram showing the entire configuration of an online total nitrogen measuring device as an example of the water quality analyzer according to the present invention. Here, the same symbols are attached to the similar components as in the above-described online total nitrogen measuring device 101, and the descriptions thereof are not repeated.

(8) An online total nitrogen measuring device 1 is provided with a sample tank 2, a syringe pump (weighing unit) 12, a first multiport valve 20, a second multiport valve 30, a reactor 40, a measuring unit 50 and a computer 60.

(9) The computer 60 is provided with a CPU (control unit) 61, a display unit 62 such as a monitor, and a memory 63. In addition, the functions that are processed by the CPU 61 are described using the blocks, which are an acquisition unit 61a for acquiring the light intensity I from a photodiode (detection unit) 52, an absorbance calculation unit 61b for calculating the absorbance on the basis of the detected light intensity I, a determination unit 61c for determining whether or not a predetermined amount of the prepared liquid sample S3 has been contained on the basis of the change in the light intensity I(L), and a weighing unit control unit 61d for controlling the syringe pump 12.

(10) Furthermore, in order to determine an abnormality in the collection of water, the memory 63 stores in advance a standard liquid amount to be fed L (900 l, for example) that provides the state where (2) an increase or decrease in the light intensity I is relatively large when a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3 is fed.

(11) The determination unit 61c controls the system so as to determine whether or not a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3 has been contained within the measuring cell 53 on the basis of the change in the light intensity I(L) detected by the photodiode 52 when the prepared liquid sample S3 is contained within the measuring cell 53.

(12) Concretely, the amount of inclination in the curve of the change in the light intensity I(L) detected by the photodiode 52 is sequentially checked when the reacted liquid sample S2 is contained within the measuring cell 53. When the amount of inclination becomes a predetermined value or less, it is determined to be the starting point of a peak. When the amount of inclination is changed from negative to positive, it is determined to be the peak (fed liquid amount point L). When the amount of inclination becomes a predetermined value or less, it is determined to be the end point of the peak. In the case where the fed liquid amount point L is greater than the standard fed liquid amount L, it is determined that the amount of the liquid fed into the measuring cell 53 runs short, and a warning is displayed on the display unit 62. In the case where no peak has been detected as well, it is determined that the amount of the liquid fed into the measuring cell 53 runs short, and a warning is displayed on the display unit 62.

(13) Here, the method for automatically analyzing the total nitrogen concentration of a liquid sample S by using the above-described online total nitrogen measuring device 1 is described. The weighing unit control unit 61d of the computer 60 outputs a drive signal to the pulse motor 12c in accordance with a predetermined timing so that a predetermined amount (a) of the liquid sample S is weighed and collected from the sample tank 2 by means of a syringe pump 12. A drive signal is again outputted to the pulse motor 12c so that a predetermined amount (b) of diluent water is weighed and collected from the container 5 by means of the syringe pump 12 so as to dilute the liquid sample S within the syringe 12a. Next, the weighing unit control unit 61d outputs a drive signal to the pulse motor 12c so that a predetermined amount (c) of a sodium hydroxide solution is added from the container 7 into the syringe 12a, and a predetermined amount (d) of a potassium peroxydisulfate solution is added from the container 6 into the syringe 12a so as to provide a prepared liquid sample S1. After that, a drive signal is again outputted to the pulse motor 12c so that a predetermined amount (a+b+c+d) of the prepared liquid sample S1 is introduced from the syringe pump 12 to the reactor 40.

(14) In the reactor 40, the prepared liquid sample S1 is irradiated with ultraviolet rays from the ultraviolet ray lamp 42 for approximately 20 minutes so as to oxidatively decompose the nitrogen compounds into nitrate ions, and at the same time decompose the potassium peroxydisulfate in the liquid into potassium sulfate. After all the potassium peroxydisulfate has been decomposed, the liquid is further irradiated with ultraviolet rays for 5 to 20 minutes so as to reduce the nitrate ions into nitrite ions. After the completion of these reactions, the weighing unit control unit 61d outputs a drive signal to the pulse motor 12c so that a predetermined amount (a+b+c+d) of the reacted liquid sample S2 is weighed and collected by means of the syringe pump 12. A drive signal is again outputted to the pulse motor 12c so that a predetermined amount (e) of hydrochloric acid is added from the container 8 into the syringe 12a so as to generate a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3.

(15) Next, the weighing unit control unit 61d outputs a drive signal to the pulse motor 12c so that a predetermined amount (A+b+c+d+e) of the prepared liquid sample S3 is introduced from the syringe pump 12 to the measuring cell 53. At this time, the acquisition unit 61a allows the semiconductor laser element 51 to emit a laser beam so as to allow the photodiode 52 to detect a change I(L) in the light intensity. Next, the determination unit 61c determines whether or not a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3 has been contained in the measuring cell 53 on the basis of the detected change I(L) in the light intensity.

(16) In the case where it is determined that a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3 has been contained, the absorbance calculation unit 61b measures the absorbance at 220 nm on the basis of the detected light intensity I so that the total nitrogen concentration in the liquid sample S is calculated and stored in the memory 63. Meanwhile, in the case where it is determined that a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3 has not been contained, the determination unit 61c displays a warning on the display unit 62.

(17) As described above, the online total nitrogen measuring device 1 that has the configuration according to the present invention makes it possible to find an abnormal state such as running short of a liquid or a liquid leakage at an early stage.

(18) <Other Embodiments>

(19) <1> In the above-described online total nitrogen measuring device 1, a configuration where it is determined whether or not a predetermined amount (a+b+c+d+e) of the prepared liquid sample S3 has been contained within the measuring cell 53 is shown. Instead of this, however, a configuration may be provided where a light source unit and a detection unit are provided in the reactor 40 in such a manner that it is determined whether or not a predetermined amount (a+b+c+d+e) of the prepared liquid sample S1 has been contained within the reactor 40.

(20) <2> Though the configuration in the above-described embodiment relates to a case where the present invention is applied to the online total nitrogen measuring device 1, the configuration may relate to a case where the invention is applied to another water quality analyzer instead.

INDUSTRIAL APPLICABILITY

(21) The present invention can be applied to a water quality analyzer such as a total nitrogen measuring device for measuring the total nitrogen concentration in a liquid sample.

REFERENCE SIGNS LIST

(22) 1: online total nitrogen measuring device (water quality analyzer) 51: semiconductor laser element (light source unit) 52: photodiode (detection unit) 53: measuring cell (sample container) 53e: liquid sample introduction port 61c: determination unit