Water quality analyzer

Abstract

This water quality analyzer comprises: a syringe pump for sucking and discharging a liquid; a plurality of containers for storing mutually different kinds of liquids; a switching mechanism to which a first flow passage leading to the syringe pump is fluidically connected and a plurality of second flow passages respectively leading to the plurality of containers are fluidically connected, and which is configured to selectively connect any one of the plurality of containers to the syringe pump; a liquid sensor which is provided such that a signal outputted varies depending on the presence or absence of the liquid inside the first flow passage, or which is provided such that a signal outputted differs between when the liquids are present inside all of the plurality of second flow passages and when the liquids are present inside only a part of the plurality of second flow passages; and a container management unit which is configured to detect, on the basis of the signal outputted from the liquid sensor, whether or not an unusable container exists among the plurality of containers.

Description

water quality analyzer

[0001] The present invention relates to a water quality analyzer such as a total nitrogen / total phosphorus measuring device (hereinafter referred to as a TN / TP meter).

[0002] Water quality analyzers such as TN / TP meters are equipped with a syringe pump and a multiport valve. The syringe pump is connected via the multiport valve to containers containing a measurement cell as well as sample liquid, reagents, dilution water, etc., allowing for the collection of sample water, the addition of reagents to the sample water, dilution of the sample water, and the transfer of the sample water to the measurement cell (see Patent Document 1).

[0003] JP 2016-080441 A

[0004] In water quality analyzers like those described above, one of the containers connected to the multiport valve may become unusable if the liquid runs out or if a leak occurs in the tubing leading to that container. If an unusable container is present among the containers connected to the multiport valve, the syringe pump cannot draw in the liquid necessary for measurement, making it impossible to perform accurate measurements. However, previous water quality analyzers were not able to automatically recognize whether or not an unusable container was present.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to make it easier to detect whether or not there is an unusable container among multiple containers connected to a multiport valve.

[0006] The water quality analyzer of the present invention comprises a syringe pump for sucking in and discharging liquid, a plurality of containers containing different types of liquid, a switching mechanism to which a first flow path leading to the syringe pump is fluidly connected and a plurality of second flow paths leading to each of the plurality of containers are fluidly connected, and which is configured to selectively connect any one of the plurality of containers to the syringe pump, a liquid sensor configured to output a signal that changes depending on the presence or absence of liquid inside the first flow path, or to output a different signal when liquid is present inside all of the plurality of second flow paths and when liquid is present only in some of the plurality of second flow paths, and a container management unit configured to detect whether any of the plurality of containers is unusable based on the signal output from the liquid sensor.

[0007] According to the water quality analyzer of the present invention, a liquid sensor is provided that outputs a signal that changes depending on the presence or absence of liquid inside a first flow path that fluidly connects a syringe pump and a switching mechanism, or that outputs a different signal when liquid is present inside all of a plurality of second flow paths for fluidly connecting a plurality of containers to the switching mechanism and when liquid is present only in some of the plurality of second flow paths, and a container management unit that is configured to detect whether there is an unusable container among the plurality of containers based on the signal output from the liquid sensor, thereby making it easy to detect whether there is an unusable container among the plurality of containers connected to the switching mechanism.

[0008] It is a schematic diagram showing the configuration of one embodiment of a water quality analyzer. It is a diagram showing an example of connection of a liquid sensor in the same embodiment. It is a schematic diagram showing another embodiment of a water quality analyzer.

[0009] Hereinafter, an embodiment of a water quality analyzer according to the present invention will be described with reference to the drawings.

[0010] Figure 1 shows a schematic configuration of one embodiment of a water quality analyzer. The water quality analyzer in this embodiment is a TN / TP meter that can measure the total nitrogen concentration (TN concentration) and total phosphorus concentration (TP concentration) in sample water.

[0011] The water quality analyzer 1 of this embodiment includes a syringe pump 2, a first multiport valve 4, a second multiport valve 6, a measuring cell 8, a reactor 10, a controller 62, and the like.

[0012] The first multiport valve 4 and the second multiport valve 6 are, for example, eight-port valves, each having one common port and eight selection ports numbered from port 1 to port 8, with the common port selectively fluidly communicating with any one of the selection ports numbered from port 1 to port 8. In the drawing, the first to eighth ports of each valve 4, 6 are numbered "1" to "8," respectively.

[0013] The common port of first multiport valve 4 is fluidly connected to a first port of second multiport valve 6. A syringe pump 2 is fluidly connected to the common port of the second multiport valve. Syringe pump 2 is used to draw in and discharge fluid. A stirring pump 34 is fluidly connected to syringe pump 2, and the liquid can be stirred within syringe pump 2 by driving stirring pump 34.

[0014] Among the selection ports provided in the first multiport valve 4, a container 14 for storing sample water is fluidly connected to the first port via a flow path 13, sample water is supplied to the second port online via piping from a sample water supply source such as a drainage facility, a container 12 for storing span liquid is fluidly connected to the third port via a flow path 11, a reactor 10 is fluidly connected to the fourth port, a container 20 for storing dilution water is fluidly connected to the sixth port via a flow path 19, a measurement cell 8 is fluidly connected to the seventh port, and containers 16 and 18 for storing different types of standard samples are fluidly connected to the eighth port via a first selector valve 38. The containers 16 and 18 are fluidly connected to the selector valve via flow paths 15 and 17, respectively, and either the container 16 or 18 is fluidly connected to the eighth port of the first multiport valve 4. The fifth port of the first multiport valve 4 is connected to a waste liquid destination and a waste water destination via a selector valve, and can selectively direct liquid within the device to either the waste liquid destination or the waste water destination.

[0015] Of the selection ports provided in the second multiport valve 6, the second to seventh ports are fluidly connected to containers 22, 24, 26, 28, 30, and 32 for storing reagents via flow paths 21, 23, 25, 27, 29, and 31 (plurality of second flow paths), respectively.

[0016] The measurement cell 8 is a cell for measuring the TN concentration and / or TP concentration of the sample water, and a light-emitting part and a light-receiving part are arranged on either side of the measurement cell 8. The liquid in the measurement cell 8 is drained outside the device.

[0017] The reactor 10 oxidizes various components in the sample water, such as nitrogen compounds and phosphorus compounds, by irradiating the mixed solution inside with ultraviolet light from a light source. The solution inside the reactor 10 is discharged outside the device by driving a discharge pump 36.

[0018] The first multiport valve 4 and the second multiport valve 6 constitute a switching mechanism for switching the connection destination of the syringe pump 2. By switching the connection destination of the syringe pump 2 using the first multiport valve 4 and the second multiport valve 6, it is possible to perform processes such as collection of an online sample or a sample stored in a container 12 by the syringe pump 2, addition of a reagent to the sample collected in the syringe pump 2, transfer of the sample to the reactor 10, transfer of the sample to the sample cell 8 after reaction processing in the reactor 10, and cleaning of the inside of the syringe pump 2.

[0019] Capacitance sensors 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, and 58 are provided in flow paths 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, and 31 to detect the presence of liquid in each flow path. These capacitance sensors are arranged so that electrical continuity exists between the electrodes when liquid is present in each flow path and no electrical continuity exists between the electrodes when liquid is not present in each flow path. Output signals from capacitance sensors 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, and 58 are input to a sensor circuit 64 provided within a controller 62 that controls each driving component of the water quality analyzer 1. The controller 62 can be implemented by an electronic circuit including a CPU (central processing unit). Alternatively, the sensor circuit 64 may be provided separately from the controller 62 and output a signal from the sensor circuit 64 to the controller 62.

[0020] 2 , the electrodes of capacitance sensors 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, and 58 are connected in series, and electrical continuity between the sensor circuit 64 and ground is established only when liquid is present between the electrodes of all of the liquid sensors. This allows the sensor circuit 64 to generate different electrical signals depending on whether liquid is present in all of the flow paths 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, and 31 or only in some of the flow paths. For example, the sensor circuit 64 can generate a signal of “1” when liquid is present in all of the flow paths 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, and 31, and a signal of “0” when liquid is present in only some of the flow paths. In this way, capacitance sensors 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, and 58 connected in series with each other constitute a liquid sensor that outputs different signals when liquid is present in all of flow paths 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, and 31 and when liquid is present in only some of the flow paths.

[0021] As described above, by connecting multiple capacitance sensors in series, the presence or absence of liquid in multiple flow paths can be detected by a single electrical signal, eliminating the need to provide a sensor circuit for each capacitance sensor. This simplifies the circuit configuration for detecting the presence or absence of liquid in each flow path, and reduces costs.

[0022] The controller 62 includes a container management unit 66. The container management unit 66 is a function obtained by executing software in the controller 62. The container management unit 66 is configured to monitor signals from the capacitance sensors 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, and 58 acquired by the sensor circuit 64, and to detect whether all of the containers 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32 are usable, or conversely, whether any of the containers 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32 is unusable. An unusable container refers to a state in which the liquid in the container has run out or a liquid leak has occurred in a flow path or the like leading to the container, making it impossible to draw liquid into the container even when the syringe pump 2 is fluidly connected to the container.

[0023] The function of the container management unit 66 is premised on the premise that all of the flow paths 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, and 31 are filled with liquid before the start of measurement. Therefore, it is preferable that the controller 62 sequentially connects the syringe pump 2 to the containers 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32 before the start of sample measurement, thereby executing an operation to fill all of the flow paths 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, and 31 with liquid.

[0024] The controller 62 constantly monitors the states of the multiport valves 4 and 6 and the operating state of the syringe pump 2, and stores information about which container the syringe pump 2 is currently drawing liquid from. The container management unit 66 can use this information together with the signal acquired by the sensor circuit 64 to detect which of the containers 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32 has become unusable. As a specific example, when the signal acquired by the sensor circuit 64 changes from "1" to "0" while the syringe pump 2 is drawing liquid, it can detect that a container to which the syringe pump 2 is fluidly connected has become unusable.

[0025] In the embodiment of Figure 1, a capacitance sensor is provided in each of the flow paths leading to all of the containers storing liquid, and all of these capacitance sensors are connected in series. However, the present invention is not limited to this. Capacitance sensors may also be provided in flow paths leading to some of the containers storing liquid, and these sensors may be connected in series to acquire a single signal using a sensor circuit. For example, capacitance sensors may be provided only in flow paths 21, 23, 25, 27, 29, and 31 leading to containers 22, 24, 26, 28, 30, and 32 storing reagents, and these sensors may be connected in series. This makes it easy to monitor whether the reagents used in the measurement have run out.

[0026] When using information held by the controller 62, it is not necessary to provide capacitance sensors on the multiple flow paths leading to the container as shown in FIG.

[0027] In the water quality analyzer 1′ shown in FIG. 3 , a capacitance sensor 68 is provided on a flow path (first flow path) that fluidly connects the syringe pump 2 and the second multiport valve 6. A signal from the capacitance sensor 68 is input to a sensor circuit 64′ provided in a controller 62′. A container management unit 66′ provided in the controller 62 can detect whether a container fluidly connected to the syringe pump 2 is usable or not by using the signal acquired by the sensor circuit 64′ and information on which container the syringe pump 2 is currently drawing liquid from. Specifically, the container management unit 66′ monitors whether the capacitance sensor 68 detects a certain liquid when the syringe pump 2 is about to draw that liquid, thereby detecting whether the container storing that liquid is usable or not.

[0028] 1 and 3, a sensor 60 (e.g., a capacitance sensor) for detecting whether or not a liquid is present in the flow path between the first multiport valve 4 and the measurement cell 8 can be provided in the flow path between the first multiport valve 4 and the measurement cell 8. By providing the sensor 60 at this position and monitoring whether or not the sensor 60 detects the presence of a liquid when the syringe pump 2 transfers the sample water to the measurement cell 8, it is possible to monitor whether or not the transfer of the sample water to the measurement cell 8 has been performed normally.

[0029] The above-described examples are merely examples of embodiments of the water quality analyzer according to the present invention. The embodiments of the water quality analyzer according to the present invention are as follows.

[0030] In one embodiment of the water quality analyzer of the present invention, the water quality analyzer includes: a syringe pump for sucking in and discharging liquid; a plurality of containers containing different types of liquid; a switching mechanism to which a first flow path leading to the syringe pump is fluidly connected and a plurality of second flow paths leading to the plurality of containers are fluidly connected, and which is configured to selectively connect any one of the plurality of containers to the syringe pump; a liquid sensor that is configured to output a signal that changes depending on the presence or absence of liquid inside the first flow path, or that is configured to output a different signal when liquid is present inside all of the plurality of second flow paths and when liquid is present only in some of the plurality of second flow paths; and a container management unit that is configured to detect whether any of the plurality of containers is unusable based on the signal output from the liquid sensor.

[0031] In a first aspect of one embodiment of the water quality analyzer of the present invention, the liquid sensor is configured to output a signal that changes depending on the presence or absence of liquid inside the first flow path, and the container management unit is configured to monitor the state of the switching mechanism and the operating state of the syringe pump, and to detect which of the multiple containers is connected to the syringe pump by the switching mechanism and which of the multiple containers is unusable based on the signal of the liquid sensor while the syringe pump is operating to suck in liquid.

[0032] In a second aspect of one embodiment of the water quality analyzer of the present invention, the liquid sensor is configured to output a first signal when liquid is present inside all of the plurality of second flow paths, and to output a second signal different from the first signal when liquid is present only in some of the plurality of second flow paths.

[0033] In the second aspect, the liquid sensor can be configured such that a plurality of capacitance sensors provided in each of the second flow paths are connected in series and a single electrical signal is output by the plurality of capacitance sensors.

[0034] In the above case, the container management unit can be configured to monitor the state of the switching mechanism and the operating state of the syringe pump, and detect which of the multiple containers is connected to the syringe pump by the switching mechanism, and which of the multiple containers is unusable based on the signal of the liquid sensor while the syringe pump is operating to suck in liquid.

[0035] An example of a water quality analyzer is a total nitrogen / total phosphorus measuring device.

[0036] REFERENCE SIGNS LIST 1, 1' Water quality analyzer 2 Syringe pump 4 First multiport valve 6 Second multiport valve 8 Measuring cell 10 Reactor 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 Container 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31 Flow path 34, 36 Pump 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 68 Capacitance sensor 62, 62' Controller 64, 64' Sensor circuit 66, 66' Container management unit

Claims

1. A water quality analyzer comprising: a syringe pump for sucking and discharging liquid; a plurality of containers containing different types of liquid; a switching mechanism to which a first flow path leading to the syringe pump is fluidly connected and a plurality of second flow paths leading to the plurality of containers are fluidly connected, and which is configured to selectively connect any one of the plurality of containers to the syringe pump; a liquid sensor configured to output a signal that changes depending on the presence or absence of liquid inside the first flow path, or to output a different signal when liquid is present inside all of the plurality of second flow paths and when liquid is present only in some of the plurality of second flow paths; and a container management unit configured to detect whether any of the plurality of containers is unusable based on the signal output from the liquid sensor.

2. The water quality analyzer of claim 1, wherein the liquid sensor is configured to output a signal that changes depending on the presence or absence of liquid inside the first flow path, and the container management unit is configured to monitor the state of the switching mechanism and the operating state of the syringe pump, and to detect which of the multiple containers is connected to the syringe pump by the switching mechanism and which of the multiple containers is unusable based on the signal of the liquid sensor while the syringe pump is operating to suck in liquid.

3. A water quality analyzer as described in claim 1, wherein the liquid sensor is configured to output a first signal when liquid is present inside all of the plurality of second flow paths, and to output a second signal different from the first signal when liquid is present only in some of the plurality of second flow paths.

4. A water quality analyzer as described in claim 3, wherein the liquid sensor is configured such that a plurality of capacitance sensors provided in each of the plurality of second flow paths are connected in series and a single electrical signal is output by the plurality of capacitance sensors.

5. The water quality analyzer of claim 4, wherein the container management unit is configured to monitor the state of the switching mechanism and the operating state of the syringe pump, and to detect which of the plurality of containers is connected to the syringe pump by the switching mechanism, and which of the plurality of containers is unusable based on the signal of the liquid sensor while the syringe pump is operating to suck in liquid.

6. The water quality analyzer of claim 1, wherein the water quality analyzer is a total nitrogen / total phosphorus measuring device.

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