CN112697989A

CN112697989A - Water quality analyzer, liquid taking and feeding method for water quality analyzer and water quality online monitoring system

Info

Publication number: CN112697989A
Application number: CN202011430707.8A
Authority: CN
Inventors: 邓守权; 吴升海; 邱华
Original assignee: Thermo Fisher Scientific Shanghai Instruments Co Ltd
Current assignee: Thermo Fisher Scientific Shanghai Instruments Co Ltd
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2021-04-23

Abstract

The invention relates to a water quality analyzer, comprising: a liquid pick-up and delivery unit comprising: a multi-way switching valve; a flow path switching valve; a pump; a reaction unit, wherein, in a liquid taking state of the liquid taking and feeding unit, the pump is configured to draw the liquid toward the flow switching valve via the multi-way switching valve, and in a liquid feeding state of the liquid taking and feeding unit, the flow switching valve is in a second position so that the flow switching valve, the pump, the multi-way switching valve, and the reaction unit constitute a closed fluid circuit, whereby the pump is configured to feed all or a part of the liquid drawn in the liquid taking state into the reaction unit via the multi-way switching valve and the first port, and gas in the reaction unit flows toward the flow switching valve via the second port. The invention also relates to a liquid taking and feeding method for the water quality analyzer and an online water quality monitoring system.

Description

Water quality analyzer, liquid taking and feeding method for water quality analyzer and water quality online monitoring system

Technical Field

The invention relates to a water quality analyzer, which can be used for measuring the content of one or more substances in a water sample so as to analyze the basic condition of water quality on line. The invention also relates to a water quality on-line monitoring system comprising the water quality analyzer. In addition, the invention relates to a liquid taking and feeding method for the water quality analyzer.

Background

Currently, the problem of water pollution is attracting increasing attention as a prominent environmental protection problem. In order to protect the water environment in which people live and ensure the drinking water hygiene of people, on one hand, the water quality in production and life needs to be detected, and on the other hand, the monitoring on the discharge of various kinds of production and domestic sewage needs to be enhanced.

In the prior art, it is known to use water quality analyzers for detection and analysis, and such water quality analyzers can perform online monitoring of the content of various substances such as silicon, phosphate and the like in water samples of various industries such as surface water, drainage of ditches, domestic sewage, industrial process water, industrial wastewater and the like by a colorimetric method. For this purpose, such water quality analyzers are provided with a reaction cell, which can also be used as a measuring cell (or reaction/measuring cell). The reaction measuring cell is installed in a control module capable of flexibly setting temperature. A battery may be mounted in the control module. The control module is provided with two groups of high-precision optical measurement systems to realize the precise measurement of the contents of various substances such as silicon, phosphate and the like.

For example, in the conventional COD water quality on-line monitor, the main flow path includes a liquid taking and delivering unit composed of a high-precision syringe pump, a multi-way valve (e.g., four-way valve, six-way valve, eight-way valve, etc.), and a buffer and liquid storing mechanism. The liquid taking and feeding unit can realize the sequential sample feeding function of different reagents, standard liquid and samples and push the reagents, the standard liquid and the samples into the reaction measuring cell for chemical reaction.

Typically, there are some particles, micelles or other forms of impurities in the air, where large amounts of silica, phosphate or other types of contaminants are present in these particles or the like. Therefore, although various means for ensuring the accuracy and reliability of the water quality analysis result have been adopted in the prior art, such as accurately quantifying the volume of various water samples, reagents, standard solutions and other liquids (for example, the volume can be accomplished by expensive syringe pumps, but the cost of the whole water quality analyzer is generally greatly increased), due to the large amount of ambient air in the flow path of the water quality analyzer, the final reaction result in the reaction measurement cell is inevitably affected by the particulate matters or pollutants in the air, and thus poor water quality measurement and analysis accuracy is caused.

Furthermore, it is often necessary to efficiently mix the sample, reagents and other liquids fed into the reaction measuring cell during the water quality analysis, and bubbling of the liquid in the reaction measuring cell with external gas, especially air, is often used (for example, feeding bubbles into the reaction measuring cell). If a large volume of air is used (e.g., by sparging) to mix the sample or reagent, various particulates and/or contaminants in the air will also be introduced into the reaction/measurement cell, thereby contaminating the mixture and thus obtaining undesirable test results.

In addition, since the water quality analyzer generally includes a multi-way valve for switching the sample, the reagent, and other liquids, which mostly adopts a configuration of rotary switching, there will inevitably be a problem that the liquid (e.g., the reagent) in the previous process is contaminated with the liquid in the subsequent process as the rotary switching. Since the quantification of reagents is usually minimal, such contamination problems can lead to serious measurement and analysis accuracy errors, and it is therefore desirable to avoid such contamination.

Therefore, there is a continuing need in the art for an improved water quality analyzer that avoids many of the above-mentioned problems, and it is desirable that the cost of the water quality analyzer remain low while ensuring the accuracy and reliability of the water quality analysis.

Disclosure of Invention

In order to solve the above problems, the present invention provides a water quality analyzer comprising: a liquid pick-up and delivery unit comprising: a multi-way switching valve; a flow path switching valve switchable between a first position and a second position; a pump disposed on a flow path between the multi-way switching valve and the flow path switching valve; a reaction unit configured to contain a liquid to be fed and including a first port connected to the multi-way switching valve and a second port connected to the flow switching valve, wherein, in a liquid take-out state of the liquid take-out unit, the pump is configured to draw out the liquid toward the flow switching valve via the multi-way switching valve, and wherein, in the liquid feeding state of the liquid taking and feeding unit, the flow path switching valve is in the second position, so that the flow path switching valve, the pump, the multi-way switching valve and the reaction unit form a closed fluid loop, whereby the pump is configured to send all or a portion of the liquid pumped in the liquid-withdrawing state into the reaction unit via the multi-way switching valve and the first port, and the gas in the reaction unit flows to the flow path switching valve through the second port.

By means of the water quality analyzer, pollutants in the outside air can be prevented from being introduced into the flow path inside the water quality analyzer in the water quality monitoring process to the greatest extent, so that the accuracy of the monitoring result can be greatly improved, and meanwhile, the design of a fluid loop of the water quality analyzer is simple and reliable.

In some embodiments, the flow path switching valve may be in a first position in which it can communicate with outside air in the liquid-withdrawing state. Since the liquid is also communicated with the atmosphere at the time of liquid extraction, it is not necessary to additionally provide a port to the atmosphere to balance the pressure in the flow path at the time of liquid extraction.

Preferably, the multi-way switching valve includes a liquid inlet port and a liquid delivery port, the first port being in fluid communication with the liquid delivery port, in the liquid take state the pump being configured to draw liquid from the liquid inlet port via the multi-way switching valve towards the flow-path switching valve, and in the liquid delivery state the pump being configured to deliver all or a portion of the drawn liquid to the reaction unit via the liquid delivery port and the first port.

Liquid taking and liquid sending are respectively realized through different ports of the multi-way switching valve, so that the operation flexibility can be improved, and the possibility of port pollution is reduced.

For example, the liquid is at least one of a water sample and a reagent, and the multi-way switching valve includes an inlet port corresponding to the at least one. Assigning different ports of the multi-way switching valve for different liquid types may advantageously enable various desired switching (e.g., timing), reduce contamination probability, etc.

Preferably, the liquid is a water sample, and in the liquid taking state, the pump is configured to draw the liquid from the liquid inlet port onto the flow path beyond the flow path switching valve via the multi-way switching valve and the flow path switching valve, and in the liquid sending state, the pump is configured to send the liquid on the flow path between the liquid inlet port and the flow path switching valve into the reaction unit.

That is, in the case that the liquid is a water sample (i.e., a liquid with a large liquid amount is taken), the water sample is extracted beyond the position of the flow path switching valve, even to the position of the waste liquid reservoir, but the volume of the water sample can be quantified by the fixed volume of the flow path between the liquid inlet port and the flow path switching valve during liquid feeding, thereby achieving the purpose of simplifying the quantification.

When the liquid is a water sample, in a liquid feeding state, the gas in the reaction unit flows in the closed fluid loop to a position beyond the flow path switching valve via the second port toward the pump.

In other words, due to the larger amount of sampled water, the gas in the reaction unit is correspondingly exhausted more, so that the gas flows along the closed fluid circuit until the position beyond the flow path switching valve (i.e., in the flow path between the pump and the flow path switching valve). Since the fluid circuit is closed, the entire circuit is not in communication with the outside air despite the high gas outflow from the reaction unit, and the gas inside the reaction unit is always internally circulated, thereby reducing the risk of introducing contaminants.

In some embodiments, the liquid is a reagent and, in the liquid draw state, the pump is configured to draw liquid from the liquid inlet port onto a flow path between the multi-way switching valve and the pump via the multi-way switching valve.

That is, in the case where the liquid is a reagent (i.e., a liquid having a small amount of liquid to be taken), it is only necessary to draw the reagent to the flow path between the multi-way switching valve and the pump, and it is not necessary to draw the reagent to the flow path between the pump and the flow path switching valve or even beyond the position of the flow path switching valve.

Advantageously, the multi-way switching valve further comprises a common port, the common port being capable of fluid communication with the inlet port in a liquid-withdrawal state and the common port being capable of fluid communication with the liquid-delivery port in a liquid-delivery state. By means of the common port of the multi-way switching valve, the liquid inlet port and the liquid conveying port can be conveniently butted, so that the operation is simplified, and a compact internal structure is realized.

It is particularly advantageous if the pump for taking and delivering liquid is constructed as a peristaltic pump which can be rotated in the forward and reverse direction. The liquid taking and feeding actions can be completed by simple structure and flow path design by means of positive and negative rotation of the same peristaltic pump. In particular, peristaltic pumps are inexpensive and can also be used to dose liquids by controlling the number of turns they make.

The second port of the reaction unit is configured to be selectively vented to outside air via a third valve. By means of the selectively supplied external air (equalizing pressure), a rapid discharge of the liquid in the reaction cell can be achieved.

The invention also relates to a liquid taking and feeding method for the water quality analyzer, and the water quality analyzer comprises the following steps: a liquid taking and delivering unit comprising: a multi-way switching valve; a flow path switching valve switchable between a first position and a second position; a pump disposed on a flow path between the multi-way switching valve and the flow path switching valve; a reaction unit configured to contain a liquid to be fed, and including a first port connected to the multi-way switching valve and a second port connected to the flow-path switching valve; the liquid taking and delivering method comprises the following steps: liquid taking step: switching the flow path switching valve to a first position, and pumping liquid towards the flow path switching valve through the multi-way switching valve by a pump; liquid feeding step: the flow path switching valve is switched to the second position so that the flow path switching valve, the pump, the multi-way switching valve, and the reaction unit constitute a closed fluid circuit, and all or a part of the liquid extracted in the liquid extraction state is sent to the reaction unit by the pump via the multi-way switching valve and the first port, and the gas in the reaction unit flows to the flow path switching valve via the second port.

By means of the liquid taking and feeding method for the water quality analyzer, pollutants in the outside air can be prevented from being introduced into a flow path inside the water quality analyzer in the water quality monitoring process to the great extent, and therefore the accuracy of a monitoring result can be greatly improved.

Preferably, the pump is a peristaltic pump, and in the liquid taking step, the liquid is taken out by rotating the peristaltic pump in the forward direction, and in the liquid feeding step, the liquid is fed into the reaction unit by rotating the peristaltic pump in the reverse direction.

In particular, when the liquid is a water sample, in the liquid taking step, the liquid is pumped by a pump from the liquid inlet port to the flow path beyond the flow path switching valve via the multi-way switching valve, and in the liquid feeding step, the liquid between the liquid inlet port and the flow path switching valve is fed by a pump to the reaction unit.

Further, when the liquid is a reagent, in the liquid extracting step, the liquid is extracted by the pump through the multi-way switching valve onto a flow path between the multi-way switching valve and the pump.

Finally, the invention also relates to an online water quality monitoring system, which comprises the water quality analyzer and at least one reagent reservoir, wherein the water quality analyzer comprises interfaces which are respectively in fluid connection with the waste liquid reservoir and the reagent reservoir.

Drawings

Fig. 1 illustrates a schematic diagram of an online water quality monitoring system according to an embodiment of the present invention, in which a liquid extracting and delivering unit is extracting a water sample;

FIG. 2 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow-path switching valve is in a second position to form a closed fluid circuit;

fig. 3 illustrates a schematic diagram of an online water quality monitoring system according to an embodiment of the present invention, wherein a liquid taking and sending unit is sending a liquid to a water sample;

fig. 4 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the invention, wherein the flow-path switching valve is in a first position and the liquid taking and sending unit is ready for taking a first liquid of the reagent;

fig. 5 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow-path switching valve is still in the first position, and the liquid taking and sending unit is taking liquid for the first time for the reagent;

fig. 6 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow-path switching valve is still at the first position, and the common port of the multi-way valve of the liquid taking and sending unit is switched from being communicated with the liquid inlet port to being communicated with the liquid sending port;

fig. 7 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow-path switching valve is still in the first position and the liquid-taking and feeding unit feeds the extracted reagent into the waste liquid tank;

fig. 8 is a schematic diagram illustrating an on-line water quality monitoring system according to an embodiment of the invention, in which the flow-path switching valve is in a second position, and the liquid extracting and sending unit extracts a part of the water sample in the reaction unit to the flow path between the multi-way switching valve and the flow-path switching valve;

fig. 9 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow switching valve is in a first position, the multi-way switching valve switches from communicating with the liquid feeding port to communicating with the liquid inlet port for the reagent, and the liquid taking and feeding unit is ready to take liquid from the reagent;

fig. 10 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow-path switching valve is in a first position and the liquid taking and sending unit is taking liquid from the reagent;

fig. 11 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, in which the flow-path switching valve is in a second position, and the liquid taking and sending unit is sending the reagent and a part of the previously extracted water sample into the reaction unit;

fig. 12 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the flow path switching valve is still in the second position and the reagent is mixed with the water sample in the reaction unit;

fig. 13 is a schematic diagram illustrating an on-line water quality monitoring system according to an embodiment of the present invention, in which the flow-path switching valve is in a second position, and the liquid pumping unit pumps a part of the mixed liquid in the reaction unit to the flow path between the multi-way switching valve and the flow-path switching valve;

fig. 14 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, wherein the first valve is switched to a position where the pump is in direct communication with an external reagent container and the tapping unit is ready to tap another reagent;

fig. 15 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the invention, wherein a tapping unit is tapping another reagent through a first valve;

FIG. 16 illustrates a schematic diagram of an on-line water quality monitoring system according to one embodiment of the present invention, wherein the first valve is switched to a position that places the pump in direct communication with the multi-way switching valve;

fig. 17 illustrates a schematic diagram of an on-line water quality monitoring system according to an embodiment of the present invention, in which a liquid taking and feeding unit is feeding another reagent extracted together with a previous mixed liquid into a reaction unit;

fig. 18 illustrates a schematic diagram of an online water quality monitoring system according to another embodiment of the present invention, in which a liquid extracting and delivering unit is extracting a liquid from a water sample;

fig. 19 illustrates a schematic diagram of an online water quality monitoring system according to another embodiment of the present invention, in which a liquid taking and sending unit is sending a liquid to a water sample;

fig. 20 illustrates a schematic diagram of an on-line water quality monitoring system according to another embodiment of the present invention, wherein a liquid extracting and delivering unit is extracting a reagent;

fig. 21 illustrates a schematic diagram of an online water quality monitoring system according to another embodiment of the present invention, in which a liquid taking and delivering unit is delivering a reagent;

fig. 22 is a schematic diagram illustrating an on-line water quality monitoring system according to another embodiment of the present invention, in which a liquid sampling and sending unit is pumping a sample of water and a reagent in a reaction unit to a flow path between a multi-way switching valve and a pump;

fig. 23 illustrates a schematic diagram of an on-line water quality monitoring system according to another embodiment of the present invention, in which a liquid taking and sending unit is sending extracted water samples and reagents back into a reaction unit;

fig. 24 illustrates a schematic diagram of a water quality analyzer according to still another embodiment of the present invention, in which a water sample can flow therein via two ports of a multi-way switching valve;

fig. 25 illustrates a schematic diagram of a multi-way switching valve of the water quality analyzer according to the embodiment of fig. 24, wherein the multi-way switching valve illustratively contains ten ports;

fig. 26 is a schematic structural view schematically illustrating a multi-way switching valve of the water quality analyzer according to the embodiment of fig. 24;

27A-27B illustrate schematic diagrams of a water quality analyzer according to the embodiment of FIG. 24, wherein a common port of a multi-way switching valve is in communication with two ports for water samples in sequence;

fig. 28A-28B illustrate schematic diagrams of a water quality analyzer according to the embodiment of fig. 24, in which a common port of a multi-way switching valve is in turn in communication with two ports for reagents.

List of reference numerals:

100 water quality analyzer;

10 a reaction unit;

12 a first port;

14 second port

20 multi-way switching valves;

21, a groove;

22 a common port;

24 a liquid delivery port;

26a first inlet port;

28a second inlet port;

30 pumps;

a 40-flow switching valve;

50 a first valve;

60 a third valve;

70 a fourth valve;

80 a liquid sensor;

82 a first sensor;

84 liquid taking pump;

86 liquid feeding pump;

90 a controller;

200 a water sample reservoir;

R1-R4 reagent reservoir;

a standard liquid reservoir of S1/S2;

400 waste reservoir.

Detailed Description

First, in the respective drawings of the present invention, only the basic fluid connection relationship between the respective components of the water quality analyzer 100 is schematically illustrated, and other necessary components (e.g., a flow path control component, a power supply component, a driving component, etc.) in the fluid circuit are not specifically illustrated. It will be understood by those skilled in the art that the components not shown are not essential to the invention and will not be described further herein.

Secondly, the water quality analyzer 100 of the present invention can be applied to various water quality measurement applications, such as the measurement of indexes such as chemical oxygen demand, ammonia nitrogen content, and the like. Further, it is to be understood that the water quality analyzer 100 of the present invention may be used in other types of monitoring and analyzing devices for measuring other liquid components than water quality. Therefore, in the present invention, an object to be fed into the reaction unit is referred to as "liquid" such as a water sample, a reagent, and the like, but the term "liquid" of the present invention may also refer to a liquid which is not fed into the reaction unit, such as a cleaning agent, a standard liquid, and the like.

Third, the term "fluid communication" in the present disclosure is not limited to direct fluid connection, but may also include indirect fluid communication of any intermediate conduit or component. Furthermore, the term "communicable" of course also includes the meaning of a switchable fluid pathway, in addition to the possibility of producing fluid communication.

Fourth, in the present invention, the term "toward a certain component or device (flow, suction, pumping, etc.)" merely indicates the direction of liquid flow, and does not indicate that liquid cannot flow beyond the component or device. In other words, the liquid may well flow towards the component or device beyond its position, only in the direction of the flow towards the component or device.

Fifth, in the drawings of the present invention, the rough position of the liquid flow is shown by thick solid lines, not the precise position, such as an exemplary relative position, and the scale of the liquid position may be exaggerated for better illustration.

Finally, the various embodiments described in this disclosure may be used interchangeably. For example, embodiments describing specific configurations and connection relationships of multi-way switching valves may be used in various embodiments of water quality analyzers. For another example, embodiments describing how a water quality analyzer better mixes a water sample and reagents may also be used in various other embodiments. For this reason, the following description is omitted.

Fig. 1 shows a schematic diagram of an on-line water quality monitoring system according to the present invention including an exemplary water quality analyzer 100. Specifically, in the system, the water quality analyzer 100 may include various interfaces to the outside to connect with other devices that provide, for example, water samples, various reagents, air, standard solutions, cleaning agents, waste solution treatment. In other words, a water sample, various reagents, air, a standard liquid, a cleaning agent (e.g., water sample reservoir 200, a plurality of reagent reservoirs, which are accommodated in the lower left side in fig. 1), and the like can be sent into the water quality analyzer 100 via the water quality online monitoring system, and the waste liquid in the water quality analyzer 100 can also be discharged to a waste liquid reservoir 400 (e.g., a waste liquid bucket or a spare bucket) located outside the system via an interface. It will also be understood that the various interfaces of the water quality analyzer are not required and that various liquids may flow directly through the piping into the various devices or components within the water quality analyzer, i.e., the boundaries of the water quality analyzer of the present invention may be dummy rather than actual physical boundaries.

First, the water quality analyzer 100 according to the present invention includes a reaction unit 10, and the reaction unit 10 may be configured to accommodate liquids, such as water samples and reagents, such as any form that can allow the water samples and the reagents to react therein, such as a reaction cell. Typically, the reaction unit 10 may comprise at least one container for holding liquid, which is independent, but may also comprise integrated further means. Herein, the term "reaction" includes, but is not limited to, mixing, measuring, blowing, chemical reaction, analysis, and the like (which may also be referred to in the art as a "reaction measurement unit", for example). Preferably, the reaction unit 10 can be installed in a control module in which temperature can be flexibly set, and equipped with a dedicated or general-purpose measuring system to achieve accurate measurement and analysis of various substances, but these are not essential to the present invention.

Next, the water quality analyzer 100 according to the present invention further includes a liquid taking and feeding unit. In the present invention, the liquid taking and feeding unit refers to a general term of each device, member, and element that draws a liquid, such as a water sample, various reagents, air, a standard liquid, a cleaning agent, and the like, in a water quality analyzer and feeds the liquid to the aforementioned reaction unit 10 or other corresponding container (e.g., a waste liquid reservoir) or other analytical instrument. In other words, any direct or indirect means for taking and delivering the liquid may be included in the scope of the liquid taking and delivering unit of the present invention.

The liquid taking and feeding unit according to the present invention may include a multi-way switching valve 20, and the multi-way switching valve 20 is mainly used to perform the pumping of the liquid into the water quality analyzer and to feed the pumped liquid (a part of the liquid or the whole liquid) into the reaction unit. To this end, the multi-way switching valve 20 may include an inlet port and a delivery port 24. That is, the inflow and outflow multi-way switching valves 20 typically employ different ports, but this is not necessarily the case. Further, it is also understood that although the port 24 is referred to as a "liquid sending port," liquid may flow not only out of the multi-way switching valve 20 via the port, but also into the multi-way switching valve 20 via the port, i.e., the term "liquid sending" does not limit the flow direction thereof.

For example, the liquid feed port 24 may be in fluid communication with the reaction unit for flowing the extracted liquid into the reaction unit via the liquid feed port. The inlet ports are associated with the various liquids to be fed into the reaction unit. It will therefore be appreciated that there may be more than one inlet port of the multi-way switching valve 20, preferably corresponding inlet ports for different liquids, such as a first inlet port 26 for a sample of water, a second inlet port 28 for one reagent, third, fourth, fifth, etc. ports for other reagents.

Preferably, the multi-way switching valve 20 may also include a common port. By common port, it is meant that the port may be in selective fluid communication with any other port of the multi-way switching valve 20. Typically, when the common port is switched to connect with any other port, the two are brought into fluid communication. More preferably, the common port is located in a central position of the multi-way switching valve 20, while the other ports are arranged, in particular uniformly, around the circumference of the multi-way switching valve 20. The specific structure of the multi-way switching valve 20 will be described in further detail below.

In order to perform the liquid extraction operation, the liquid extraction and delivery unit of the present invention may include a liquid extraction device for extracting liquid. The pumping device is typically a pump 30, but may be other equivalent similar structures. When the pump is in fluid communication with the multi-way switching valve 20, operation of the pump may pump liquid through the multi-way switching valve 20 to a flow path therebetween, and may further pump liquid to a flow path subsequent to the pump, as desired.

Preferably, the pump 30 is a low cost peristaltic pump rather than an expensive syringe pump. The cost of the whole system is reduced by avoiding the use of expensive syringe pumps and the like. Although a peristaltic pump is adopted, the peristaltic pump not only can provide power for pumping liquid, but also can complete the function of quantifying the liquid. A flow path between the multi-way switching valve 20 and the pump 30 or other additional flow paths (for example, a flow path between the pump 30 and the flow path switching valve 40, which will be described in detail later) may be used as the dosing line. The metering line may be in any particular form, including, but not limited to, a straight line, but may also be a curved line, or even a coiled tube or a loop containing a portion thereof. For example, although a straight tube is shown between the multi-way switching valve 20 and the pump 30, one or more collars may be included to extend the volumetric range that can be quantified.

A problem with peristaltic pumps is that the accuracy of the liquid dosing is not as good as with syringe pumps. To this end, the water quality analyzer 100 according to the present invention may further include a controller (not shown in the drawings), which may be configured to determine the quantitative volume by varying the pumping time of the peristaltic pump. According to the invention, the pumping capacity of the peristaltic pump is related to the angle through which the rollers of the peristaltic pump rotate. That is, the pumping capacity of a peristaltic pump varies cyclically over time (i.e., the number of revolutions of the roller).

More specifically, when the peristaltic pump comprises a plurality of rollers spaced apart from one another (typically, the angular spacing between the rollers is uniform), the pumping capacity of the peristaltic pump is at a substantially fixed value during the time it takes for one roller of the peristaltic pump to rotate to a position before it reaches its adjacent roller. It is therefore advantageous to adjust the dosing volume with a pumping time of a predetermined number of revolutions of the respective roller of the peristaltic pump. For peristaltic pumps, the pumping volume for a full revolution is also typically determined, e.g., 0.2 ml/revolution. Thus, when the peristaltic pump comprises three rollers, the dosing volume of the liquid may be selected, for example, to be one-third (preferred), two-thirds (preferred), 0.2 ml, four-thirds (preferred) of 0.2 ml, and so on, in order to obtain an accurate dosing volume. Typically, the volume fraction of a roller (e.g., one-third, one-fourth, one-fifth, etc.) for a full circle of pumping volume is already very small, and can fully meet the accuracy requirements for liquid dosing. It is particularly preferred that the predetermined number of turns is not the number of full turns of the peristaltic pump, for example between one and two turns, in particular less than one turn.

Of course, such a controller of the present invention may be used instead of or in addition to setting the pumping time/predetermined number of cycles of the peristaltic pump to control other flow paths of the water quality analyzer 100, such as switching valves or other valves, etc. In other words, the water quality analyzer 100 may include one controller to integrally control all the fluid components, or may be configured with a separate controller for one or some of the fluid components. In addition, the present invention may also include other means for quantifying the volume of liquid, such as a first sensor 82 disposed in the flow path.

Advantageously, the water quality analyzer 100 according to the present invention may further include a pumping means for sending the liquid. Preferably, the pumping device is also a pump. It is particularly preferred that the pumping means is a pump 30. That is, the pump 30 may be used for taking out liquid or for feeding liquid. In some embodiments, pump 30 for taking and delivering liquid may be configured as a peristaltic pump capable of forward and reverse rotation. For example, the pump 30 is used to pump liquid when rotating clockwise and to push liquid into the reaction unit when rotating counterclockwise (but the reverse is also possible). The invention also envisages the arrangement of two different separate pumps for liquid take-off and liquid delivery respectively.

In order to solve the problem that the water quality analysis process is polluted by particles and the like existing in the air, the water quality analyzer comprises a flow path switching valve 40. The on-off flow valve 40 is in fluid communication with the aforementioned pump 30, that is, the pump 30 is arranged on the flow path between the on-off flow valve 40 and the multi-way switching valve 20, as clearly shown in fig. 1. The flow path switching valve 40 can be switched at least between two positions, for example, between a first position and a second position.

In the liquid-taking state of the liquid-taking and feeding unit, the pump 30 is configured to draw a liquid (e.g., a sample water, a reagent, etc.) toward the flow path switching valve 40 via the multi-way switching valve 20. In some embodiments, a flow path is also connected after the flow path switching valve 40 in the direction of liquid extraction, for example, to a waste reservoir or other chemical device. Preferably, the flow path switching valve 40 is in its first position when liquid is taken. At this time, the flow path switching valve 40 may communicate with the outside air via the flow path downstream thereof. It will be appreciated that since the pump 30 is drawing liquid in the direction toward the flow path switching valve 40, or even downstream thereof, in the liquid-withdrawing state, the outside air and contaminants therein are not introduced into the reaction unit or the dosing line of the water quality analyzer.

In the liquid feeding state of the liquid taking and feeding unit, the flow path switching valve 40 is in the second position. When the flow switching valve 40 is switched to the second position, the flow switching valve 40, the pump 30, the multi-way switching valve 20, and the reaction unit 10 may thus constitute a closed fluid circuit. In the present invention, the term "closed fluid circuit" means that the fluid circuit is not in communication with the outside air, i.e. no air is introduced into the fluid circuit, i.e. no substances in the air contaminate the water quality analysis process. It should be noted, however, that changing the fluid circuit from closed to non-closed is not limited to being caused by the flow switching valve 40 switching from the second position to another position (e.g., the first position), and may also be caused by the opening of other valves on the fluid circuit, for example.

When a closed fluid circuit is constructed, the pump 30 (e.g., the same peristaltic pump) may be configured to feed the liquid extracted in the liquid-extracting state in the preamble (the preamble may refer to one or more times as necessary) into the reaction unit 10 via the multi-way switching valve 20 and the first port 12 of the reaction unit 10. It will be appreciated that the present invention does not necessarily require that all of the liquid withdrawn in the liquid withdrawal state be fed to the reaction unit 10, but that only a portion of the withdrawn liquid may be fed to the reaction unit 10 depending on the amount of liquid required.

Since the reaction unit 10 itself has a certain amount of gas before the liquid is fed (because the reaction unit 10 is not in a full state), the gas in the reaction unit 10 can flow toward the flow path switching valve 40 through the second port 14 of the reaction unit 10. Whether or not gas will flow beyond the flow path switching valve 40, for example, onto the flow path between the flow path switching valve 40 and the pump 30, depends on the amount of liquid to be withdrawn and the amount of liquid to be fed into the reaction unit. In any case, the gas present in the closed fluid circuit in the liquid feeding state is only the gas originally present in the reaction unit (in a small amount), and there is no externally introduced air or other gas.

In some embodiments, the first port of the reaction unit 10 is in fluid communication with the liquid feed port 24, so in a liquid take state of the liquid take and feed unit, the pump 30 can draw liquid from the liquid inlet port (e.g., one of the plurality of liquid inlet ports) toward the flow-path switching valve 40 via the multi-way switching valve 20, and in a liquid feed state of the liquid take and feed unit, the pump 30 can feed the drawn liquid into the reaction unit 10 via the liquid feed port 24 and the first port 12.

When the liquid is a sampled (large volume) liquid, in the liquid-taking state (for example, the flow-path switching valve 40 is in its first position, but this is not essential), the pump 30 may be configured to draw sampled water from the first inlet port 26 onto the downstream flow path beyond the flow-path switching valve 40 via the multi-way switching valve 20 and the flow-path switching valve 40. For example, the pump 30 may pump a sample of water to the flow path between the flow path switching valve 40 and the waste reservoir, and even the pump 30 may pump a portion of the sample of water to the waste reservoir (depending on the particular water quality analysis requirements).

On the other hand, in the liquid feeding state, the flow path switching valve 40 is in its second position, and the pump 30 can feed the liquid on the flow path between the first liquid inlet port 26 and the flow path switching valve 40 into the reaction unit 10. That is, in some embodiments, the liquid taking unit does not push all of the sampled water extracted in the liquid taking state into the reaction unit 10, but only a part of the sampled water between the first liquid inlet port 26 and the flow path switching valve 40 is fed into the reaction unit 10. Since the entire liquid feeding circuit is closed at the time of liquid feeding, feeding this part of the water sample into the reaction unit 10 does not cause a problem of introducing outside air and contaminants. During the process of continuously flowing the water sample into the reaction unit 10, the gas originally existing in the reaction unit 10 can also flow in the same closed fluid circuit through the second port 14 of the reaction unit 10 to the flow-path switching valve 40, and even flow through the flow-path switching valve 40 to the flow path between the flow-path switching valve 40 and the pump 30.

When the liquid is a reagent (the amount is small), in the liquid-extracting state (for example, the flow switching valve 40 is in its first position, but this is not essential), the pump 30 may be configured to pump sampled water from the second liquid inlet port 28 to the flow switching valve 40 via the multi-way switching valve 20, and may pump the sampled water to a flow path that exceeds the flow path between the multi-way switching valve 20 and the pump 30 or the flow path between the pump 30 and the flow switching valve 40, but generally does not exceed the flow switching valve 40.

On the other hand, in the liquid feeding state, the flow path switching valve 40 is in its second position, and the pump 30 can feed the whole amount of the reagent to be pumped into the reaction unit 10 (that is, the liquid on the flow path between the second liquid inlet port 28 and a position before the flow path switching valve 40 is fed into the reaction unit 10).

It will of course be appreciated that small volumes of water sample may be withdrawn when the liquid is a water sample, and large volumes of water sample when the liquid is a reagent, depending on the particular solution reaction requirements for water quality analysis, but large water samples and small amounts of reagent are generally preferred.

Advantageously, the above-mentioned first port 12 of the reaction unit 10 of the present invention is located on the side of the reaction unit 10 facing the multi-way switching valve 20, and the second port 14 is located on the side of the reaction unit 10 opposite to the first port 12, but the present invention is not limited thereto, and for example, 14 may be opened at a certain height of the side of the reaction unit 10.

In addition, a liquid sensor 80 is optionally disposed between the first port 12 of the reaction unit 10 and the liquid sending port 24 of the multi-way switching valve 20 to monitor whether liquid flows through the flow path. In addition, the reaction unit 10 may also be communicatively connected to the controller 90 or other subsequent monitoring devices to enable analysis, display, processing, etc. of the (current) water quality condition.

After the water quality analyzer 100 of the present invention completes the water quality analysis, the liquid in the reaction cell 10 may be discharged out of the water quality analyzer 100. In order to be able to drain the liquid from the reaction cell 10 via the fluid circuit, it is necessary to introduce external air pressure into the reaction cell 10, otherwise the liquid cannot be drained smoothly due to the vacuum degree. For example, the second port 14 of the reaction unit 10 may be selectively vented to outside air via a third valve. For example, the third valve may be arranged on the flow path between the second port 14 and the flow path switching valve 40, but may also be arranged on another flow path in parallel with the flow path between the second port 14 and the flow path switching valve 40, as exemplarily shown in fig. 1. When the third valve is opened, the reaction unit 10 is in direct communication with the outside air via the second port 14. It will be appreciated that the third valve should remain closed during the feeding so as not to break the closed fluid circuit as described above.

In addition, a first valve 50 is optionally disposed between the multi-way switching valve 20 and the pump 30 or between the pump 30 and the flow-path switching valve 40. The first valve 50 may be configured to open and close a flow path between the multi-way switching valve 20 and the pump 30 or between the pump 30 and the flow path switching valve 40.

In some embodiments, when the first valve 50 shuts off fluid communication between the multi-way switching valve 20 and the pump 30, the first valve 50 may allow external liquid to be drawn directly onto the flow path by the pump 30 without passing through the multi-way switching valve 20. In this way, when the first valve 50 resumes the fluid communication between the multi-way switching valve 20 and the pump 30, the pumped external liquid (for example, a specific reagent) can be also sent from the pump 30 to the reaction unit 10 through the multi-way switching valve 20. This is particularly applicable where such an external liquid (e.g., another reagent) is likely to remain inside the multi-way switching valve 20 during the rotational switching of the multi-way switching valve 20, thereby affecting the accuracy of the water quality analysis results.

Furthermore, an optional fourth valve may be arranged between the flow switching valve 40 and the waste reservoir or other subsequent chemical device to enable selective fluid communication to the waste reservoir or other subsequent chemical device. Normally, when the fourth valve is open, the flow switching valve 40 is in its first position.

Next, the liquid taking and feeding process of the present invention will be exemplarily explained with reference to fig. 1 to 17.

1) Liquid taking and delivering process of water sample

As shown in fig. 1, the common port of the multi-way switching valve 20 is being connected to the first inlet port 26 for drawing water samples. At this time, the on-off flow valve 40 is in a first position where it can communicate with the outside, i.e., in a position where the on-off flow valve 40 communicates with, for example, a waste reservoir or other chemical device downstream thereof (depending on the specific position of the fourth valve), and the third valve is closed, the first valve allowing the multi-way switching valve 20 to be in fluid communication with the pump 30. In the liquid intake state of fig. 1, sampled water is drawn by the pump 30 via the first inlet port 26, the common port 22, the pump 30, the flow path switching valve 40 to a position beyond the flow path switching valve 40, for example, even to a position of the fourth valve 70.

The pump 30 may be configured to rotate in a forward direction (i.e., clockwise) to draw sampled water, for example, at a rate of 3 revolutions per second. The pump 30 may be rotated, for example, 25 revolutions, to draw a sufficient volume of the sampled water onto the flow path.

Then, as shown in fig. 2, the common port 22 is switched to communicate with the liquid sending port 24 of the multi-way switching valve 20, so that the extracted sampled water can then enter the reaction unit 10 via the liquid sending port 24 of the multi-way switching valve 20 and the first port, i.e., the lower end in the drawing, of the reaction unit 10.

It should be noted that the on-off valve 40 is now switched to its second position, so that the on-off valve 40, the pump 30, the multi-way switching valve 20 and the reaction unit 10 form a closed fluid circuit, ready for the liquid feeding state. The sample water drawn in the step of fig. 1 beyond the flow switching valve 40 is no longer in this closed fluid circuit of construction and therefore is no longer fed into the reaction unit 10 (e.g., can flow into the waste reservoir 400).

As shown in fig. 3, the liquid taking and feeding unit is in a liquid feeding state, and the pump 30 is reversed (i.e., counterclockwise). The speed of the pump 30 may be 3 revolutions per second. The pump 30 may be rotated, for example, 25 revolutions (the number of pumping revolutions may be as required) to feed all of the water sample between the first inlet port 26 and the flow-path switching valve 40 into the reaction unit 10. Meanwhile, the water sample entering the reaction unit 10 gradually pushes the original gas in the reaction unit 10 to the flow path between the reaction unit 10 and the flow path switching valve 40 along the direction toward the flow path switching valve 40, or may exceed the flow path between the flow path switching valve 40 and the pump 30 and reached by the flow path switching valve 40.

2) Initialization operation of reagents

When a reagent is first used (whether a new or a replacement reagent), it is necessary to initiate the reagent initialization operation.

As shown in fig. 4, the flow-path switching valve 40 is switched to the first position, and the multi-way switching valve 20 is switched to a position in which the common port 22 thereof communicates with the second inlet port 28. At this time, the third valve is closed and the first valve allows the multi-way switching valve 20 to fluidly communicate with the pump 30.

Then, as shown in fig. 5, the pump 30 starts to run, for example at a speed of 3 revolutions per second, and may rotate about 30 revolutions. Here, it is necessary to ensure that the reagent (in the case of the first reagent) is pumped through the multi-way switching valve 20 to the flow path between the multi-way switching valve 20 and the pump 30.

As shown in fig. 6, the flow switching valve 40 may be maintained in the first position without being switched to the second position. At this time, the common port 22 of the multi-way switching valve 20 is switched from being communicated with the second liquid inlet port 28 to being communicated with the liquid feeding port 24.

Finally, as shown in fig. 7, the pump 30 is operable to send the first reagent, which is located at a position between the liquid-sending port 24 and the multi-way switching valve 20 and the pump 30, into the waste liquid tank 400 via the flow-path switching valve 40 to discharge the water quality analyzer 100 (fig. 7 shows a state in which the reagent has been discharged).

Initialization operations can also be performed with reference to the above steps for the first use of the second, third and further reagents.

With this initialization operation, it is possible to fill the flow path from the reagent reservoir to each corresponding inlet port of the multi-way switching valve 20 with each reagent before the actual tapping. Thus, when the liquid is actually taken, the actual volume of the reagent to be pumped can be determined by setting the number of revolutions of the peristaltic pump (preferably, the number of revolutions that is a positive integral multiple of the reciprocal of the number of rollers of the pump 30, as described above). In other words, since no reagent is drawn from the reagent reservoir, the exact volumetric amount of reagent drawn can be determined.

3) (formal) reagent taking and delivering process

After feeding the sample water into the reaction unit 10, as shown in fig. 8, the flow switching valve 40 is in its second position, i.e. the flow switching valve 40, the pump 30, the multi-way switching valve 20, the reaction unit 10 now constitute a closed fluid circuit. When the common port 22 of the multi-way switching valve 20 communicates with the liquid feeding port 24, the sampled water (a part or all of the sampled water) fed into the reaction unit 10 is pumped back to the flow path by the pump 30. The pump 30 may pump the sampled water to the flow path between the multi-way switching valve 20 and the pump 30, or may pump the sampled water to the flow path between the pump 30 and the flow path switching valve 40 as shown in fig. 8

As shown in fig. 9, the flow-path switching valve 40 is switched to the first position, and the common port 22 of the plural-way switching valve 20 is switched to a position communicating with the second inlet port 28. It can be seen that there is a sample of water drawn from the reaction unit 10 on the flow path from the second inlet port 28 to a point between the pump 30 and the flow path switching valve 40.

As shown in fig. 10, the first reagent is drawn from the second inlet port 28 by the pump 30, and is drawn to a position on the flow path between the multi-way switching valve 20 and the pump 30. The amount of the first reagent pumped can be set by the number of revolutions of the pump 30, and will not be described in detail. It can be seen that as the first reagent is drawn, the sample water on the flow path is pushed further in the direction of the flow path switching valve 40.

Then, as shown in fig. 11, the flow path switching valve 40 is switched to the second position, and the first reagent and the previously pumped water sample are all sent into the reaction unit 10 together by means of the pump 30.

As shown in fig. 12, the first reagent and the water sample are mixed and reacted within the reaction unit 10. However, it is understood that, during the process of adding the first reagent to the reaction unit 10, it is not necessary to draw a part or all of the sample water already in the reaction unit 10 out of the reaction unit 10 onto the flow path. But a part of the water sample is pumped out and then the first reagent is introduced, so that the first reagent is positioned between the water sample on the flow path and the water sample in the reaction unit 10, and the mixing of the water sample and the water sample is facilitated.

When it is necessary to add another reagent (for example, a second reagent), the respective operation steps as described above may be selected to add it to the reaction unit 10, but the following operation steps may also be selected to add it to the reaction unit 10. The following procedure is particularly suitable for applications in which the further reagent can significantly influence the accuracy of the results of the water quality analysis measurements due to the rotary switching of the multi-way switching valve 20.

As shown in fig. 13, the flow switching valve 40 is switched to the second position to constitute a closed fluid circuit. The mixed liquid of the aforementioned water sample and the first reagent in the reaction unit 10 is pumped by the pump 30 again to a position on a flow path, for example, a flow path between the pump 30 and the flow path switching valve 40, via the liquid feeding port 24 and the common port 22.

As shown in fig. 14, the flow-path switching valve 40 is switched to the first position, and the first valve disposed between the multi-way switching valve 20 and the pump 30 is switched to a position that blocks fluid communication therebetween. At the same time, the first valve may also connect the pump 30 to an external reagent reservoir in preparation for drawing another reagent from the reagent reservoir.

Then, as shown in fig. 15, another reagent is pumped via the first valve and by means of the pump 30. The rotational speed of the pump 30 is advantageously selected to be small, for example 0.4 revolutions/second, and may be selected to rotate the pump 30 only a third of a revolution, two thirds of a revolution or a full revolution. It can be seen that this further reagent is not drawn beyond the position of the pump 30.

As shown in fig. 16, the flow switching valve 40 is switched to the second position again to constitute a closed fluid circuit. At the same time, the first valve is switched back to a position that allows fluid communication between the multi-way switching valve 20 and the pump 30. Here, the extracted another reagent may be sandwiched between the mixed liquids extracted from the reaction unit 10.

Finally, as shown in fig. 17, with the flow-path switching valve 40 held in the second position, the mixed liquid containing the other reagent is sent into the reaction unit 10 via the liquid-sending port 24 of the multi-way switching valve 20 by means of the pump 30 (e.g., rotated at a rotation speed of 3 revolutions per second for about 20 revolutions).

The above steps 1) to 3) may be performed in a non-sequential manner as above, for example, the reagents may be added to the reaction unit 10 first, and then the water sample may be added, but it is generally preferable to complete the initialization operation of the reagents of step 2) before the reagents are added.

By means of the present invention, in the state of the closed fluid circuit, the liquid feeding (and partial liquid taking) state is prevented from contacting the outside air with various liquids to be reacted in the reaction unit 10, thereby achieving better accuracy (in particular, accuracy and precision of 5% or less) in water quality analysis.

Assuming a water sample with 20 mg/l silicon (i.e. 30mg/l PO4), the following table can be obtained by comparing the measured data according to the present invention with the measured data of the non-closed loop pumping process (the values in table 1 are error values):

table 1: comparison of measurement data in the case of a closed loop of the invention and a non-closed loop of the prior art

In the embodiment shown in fig. 18 to 23, the water quality analyzer 100 employs two different pumps to perform the steps of taking and sending liquid, respectively. For example, both pumps may be designed as peristaltic pumps which are less expensive.

As previously mentioned, in the case of only a peristaltic pump, due to the need to dose the liquid, dosing can be done by means of physical dosing (for example, by means of the number of revolutions of the peristaltic pump, or by means of a fixed dosing line length) or optical dosing (for example, by means of the first sensor 82 of an optoelectronic pattern to identify the position reached by the liquid in the dosing line, etc.).

In this embodiment, the water quality analyzer includes a liquid switching valve for selectively communicating a pump for taking liquid (may be referred to as a liquid taking pump 84 or a drawing pump) and its flow path or communicating another pump for sending liquid (may be referred to as a liquid sending pump 86) and its flow path.

As described above, in order to uniformly mix liquids (e.g., a water sample and a reagent), it is common in the art to supply a gas (e.g., air) into the reaction unit 10 by a gas pump and perform a bubbling operation. But due to the presence of various types of contaminants in the air, these contaminants can affect the accuracy and precision of water quality measurements and analyses.

In order to solve the above problems, the present invention uses "air flow mixing" between a flow path (e.g., a metering line) and the reaction unit 10 instead of the conventional air injection or injection. Furthermore, since the contact area of the dosing line (e.g. containing the dosing ring) is very small, the contact area of the air and the mixed liquid is very small, further reducing the risk of contamination.

The general solution of the present invention is to pump the water sample and the reagent in the reaction unit 10 into a flow path (e.g., a quantitative pipeline) at a certain speed by a pump, so that the water sample and the reagent are mixed. Then, the mixture of air and liquid is pushed back into the reaction unit 10 by the pump again, and the bubbles are controlled not to be pushed into the reaction unit 10 as much as possible. This was repeated several times until the water sample and reagents were completely mixed. Thereafter, the water sample and the reagent are chemically reacted in the reaction unit 10. When the reaction is complete, it is measured (e.g., optically) in the reaction cell 10.

The liquid that has undergone the chemical reaction and is measured with the optical measurement system may be discharged into the waste reservoir 400 through the multi-way switching valve 20, a pump, and an optional three-way valve. In addition, the cleaning solution may be discharged into a cleaning solution reservoir for special treatment, or directly into a municipal wastewater treatment system. Thereby, a large amount of waste water generated can be greatly reduced, which not only protects the environment, but also reduces the operation and maintenance costs.

In the following, exemplary operating steps of how to mix a water sample and reagents are described with the aid of fig. 18 to 23:

as shown in fig. 18, the multi-way switching valve 20 is switched so that the common port 22 thereof communicates with the first liquid inlet port 26, and the pump starts to draw water sample via the multi-way switching valve 20 by switching the liquid switching valve to communicate with the flow path in which the liquid taking pump 84 is located. For example, the rotational speed of the take-up pump 84 may be 3 revolutions per second for a total of 40-50 revolutions (i.e., approximately 13-17 seconds), with the take-up rate of the sampled water being approximately 0.15 ml/revolution. The actual quantitative volume of the water sample can be determined by the number of rotations of the peristaltic pump or the length of the quantitative tube.

As shown in fig. 19, the multi-way switching valve 20 is switched to have its common port 22 communicate with the liquid sending port 24, and the liquid switching valve is switched to communicate with the flow path in which the liquid sending pump 86 is located, so that the pump starts sending the extracted sample water into the reaction unit 10. For example, the pump 86 may be rotated at 4 revolutions per second and about 25 revolutions for 6-7 seconds, so that the sampled water is also delivered at a rate of about 0.15 ml/revolution. In this process, the speed of the liquid-sending pump 86 is selected to be as small as possible to prevent as large a quantity of bubbles as possible from being introduced into the reaction unit 10 along with the water sample. Of course, the quantification of the water sample may also be by optical quantification, but this is not preferred.

As shown in fig. 20, the multi-way switching valve 20 is switched so that the common port 22 thereof communicates with the second inlet port 28, and the pump starts pumping a reagent (for example, a first reagent) via the multi-way switching valve 20 by switching the liquid switching valve to a flow path communicating with the liquid-taking pump 84. Preferably, the extraction pump 84 is operated at a relatively slow speed, for example 0.2 rpm, for about 10 seconds of reagent extraction. When the reagent is slowly pumped to the position of the photoelectric first sensor 82 or other type of sensor on the quantitative line, the liquid-taking pump 84 is immediately stopped, so that the reagent to be pumped can be quantitatively measured by the first sensor 82. The accuracy of such quantification is high, typically less than 0.5% error. Of course, the reagent may be dosed by setting the number of revolutions of the peristaltic pump or by combining the first sensor 82 with the peristaltic pump, which will not be described in detail herein. Advantageously, the volume ratio between the sample of water withdrawn and the reagent withdrawn is greater than or equal to 20 to 1, for example between 4 and 4.2 ml for the sample of water and 0.2 ml for the reagent. The present invention is not limited to such volume ratios and specific liquid volume sizes.

As shown in fig. 21, the multi-way switching valve 20 is switched so that the common port 22 thereof communicates with the liquid-feeding port 24, and the liquid switching valve is switched so as to communicate with the flow path in which the liquid-feeding pump 86 is located, so that the pump starts feeding the pumped reagent into the reaction unit 10. In this process, the speed of the liquid-sending pump 86 is selected to be as small as possible to prevent as large a quantity of bubbles as possible from being introduced into the reaction unit 10 with the reagent.

Then, as shown in fig. 22, by holding the multi-way switching valve 20 in a position in which the common port 22 communicates with the liquid sending port 24, and switching the liquid switching valve to a flow path in which the liquid taking pump 84 communicates, the pump starts to take the sample water and the reagent from the reaction unit 10 via the multi-way switching valve 20. The rotational speed of the drawing pump 84 may be, for example, 3 revolutions per second, and about 20 revolutions per minute for 7 to 8 seconds. Preferably, the volume of sampled water and reagents does not occupy the volume of all the dosing lines between the multi-way switching valve 20 and the liquid switching valve. Advantageously, only a portion of the liquid within the reaction unit 10 is withdrawn during this step, rather than all of the liquid.

Subsequently, as shown in fig. 23, by switching the liquid switching valve to the flow path leading to the liquid-sending pump 86, the liquid to be pumped is then sent back to the reaction unit 10 by the liquid-sending pump 86. During the feeding into the reaction unit 10 it is ensured that as few bubbles as possible enter the reaction unit 10 together with the liquid. The liquid-sending pump 86 rotates at a speed of, for example, 4 revolutions per second (preferably, the liquid-sending speed is faster than the liquid-drawing speed), and rotates about 20 revolutions in a period of about 5 to 6 seconds.

The steps of fig. 22-23 are repeated several times, e.g., 3-4 times, until the water sample and reagents are well mixed by repeated pumping and delivering without introducing large amounts of air bubbles.

It is to be understood that although a closed fluid circuit is not provided in fig. 18-23 via the flow switching valve 40, one skilled in the art will appreciate that the embodiments shown in fig. 18-23 (i.e., the manner in which the liquids are mixed and the associated liquid take-and-feed steps) may also be used in conjunction with the water quality analyzer 100 of the embodiment of fig. 1-17 above.

In addition to constituting a closed fluid circuit and reducing measurement errors by "air mixing" instead of conventional air injection as described above, the present invention can reduce the influence on the measurement results that is easily caused by the rotational switching of the multi-way switching valve 20 between the respective ports by improving the layout in the water quality analyzer.

Specifically, when the multi-way switching valve 20 is rotated to switch the ports, a residue of a liquid such as a water sample or a reagent may remain in the multi-way switching valve 20 to a greater or lesser extent, which may cause a large error in the next measurement. Taking the silica measurement as an example, if a high phosphate level is present in the silica sample, for example 30 mg/L. If the reagent remains in the multi-way switching valve 20, a large error of 500 to 2000ug/L occurs.

In fig. 26 is shown the internal structure of a multi-way switching valve 20, which can be formed by two (circular) discs connected to each other to enable mutual rotation (e.g. formed by snapping together facing each other). It should be understood that this internal structure is merely an example, which may take any suitable shape. In addition, while the common port 22 of the multi-way switching valve 20 is shown in FIG. 26 as being centrally located and the other individual ports are evenly distributed about the perimeter, it should be understood that this is not necessary, e.g., the individual ports may be unevenly distributed about the perimeter, the common port may be disposed off-center, the individual ports may be disposed closer to the central location than to the perimeter, and so forth.

The left side of fig. 26 schematically shows a first face of the multi-way switching valve 20, which is constituted by a first (circular) disc provided with a centrally located hole (serving as the common port 22) and a plurality of holes (serving as the remaining ports, e.g., the first inlet port 26, the second inlet port 28, etc.) evenly distributed around the central hole. The right side of fig. 26 then schematically shows the second face of the multi-way switching valve 20, which is formed by a second (circular) disc provided with a groove, in particular a narrow straight groove, extending from a substantially central position towards the periphery.

The starting point of the above-mentioned groove, i.e. the position located in the center of the second disc, is substantially aligned with the position of the first disc where the central hole is provided, while the end point of the groove, i.e. the position close to the periphery of the second disc, is substantially aligned with the position of the plurality of peripheral holes provided in the first disc. In other words, the length of this groove of the second disc is approximately equal to the distance between the central hole and the peripheral hole of the first disc. It will be appreciated that the shape of the groove, although preferably rectilinear, may also take other shapes, such as a curved groove, as long as its starting and ending points correspond to the positions of the central and peripheral holes.

As shown in fig. 25, the grooves always communicate with the central holes correspondingly when the first and second disks are rotated relative to each other, while the end points of the grooves communicate with the respective peripheral holes correspondingly as they are rotated. When the central hole communicates with the corresponding peripheral hole via the groove, fluid communication between the common port 22 of the multi-way switching valve 20 and the remaining ports (e.g., the first inlet port 26, the second inlet port 28, etc.) is achieved.

In the prior art, when the liquid extracting and sending unit is in the liquid extracting state, the sampled water may flow into the multi-way switching valve 20 from the first liquid inlet port 26, and when the multi-way switching valve 20 is switched to the position where the common port 22 thereof communicates with the first liquid inlet port 26, the sampled water may flow into the fixed-amount line and the subsequent other elements (for example, the pump 30, the flow-path switching valve 40, etc.) via the multi-way switching valve 20. When the liquid extracting and feeding unit is in a liquid feeding state, the multi-way switching valve 20 is switched to a position (i.e., a position in the figure) that makes the common port 22 communicate with the liquid feeding port 24, thereby feeding the extracted sample water into the reaction unit 10 via the liquid feeding port 24 (see the embodiment shown in fig. 1 to 17 or fig. 18 to 23 for details).

It will be appreciated that the groove that would otherwise communicate with either of the common port 22 and the perimeter port would be filled with liquid. When the multi-way switching valve 20 is rotationally switched between ports, for example, from a first inlet port to a delivery port, the liquid in the groove sweeps across a sector area that is switched from the first inlet port to the delivery port as the multi-way switching valve 20 (e.g., its second disk relative to the fixed first disk) rotates.

In order to reduce the residual influence of the sector area swept by the liquid inside the multi-way switching valve 20, in particular during the rotary switching, according to the invention the multi-way switching valve 20 can be provided with more than one inlet port, for example two inlet ports, preferably of the water sample. Preferably, the two inlet ports for the sampled water can be symmetrically distributed about the liquid feed port 24 of the multi-way switching valve 20, i.e. the peripheral port to the reaction unit 10. It will be appreciated that only one inlet port may be provided.

More preferably, as shown in fig. 24, assuming that the respective peripheral ports of the multi-way switching valve 20 are evenly distributed around the central hole, i.e., the common port 24 (shown as COM port in the drawing), the respective peripheral ports are named sequentially, for example, where the liquid feeding port 24 is labeled as No. 6 port, two liquid feeding ports for sampled water can be set at No. 4 port (right side of No. 6 port) and No. 8 port (left side of No. 6 port), which are each spaced from No. 6 port by one port.

Next, the operation steps of the water quality analyzer 100 according to the present invention for removing the residue in the multi-way switching valve 20 will be explained with reference to fig. 27A to 28B.

First, as shown in fig. 27A, the multi-way switching valve 20 is switched to a position in which its COM port (i.e., the common port 22) communicates with port No. 4 on the right side. At this time, the liquid sampling and delivering unit samples water through the port 4 of the multi-way switching valve 20, and the water sample fills the groove between the COM port and the port 4.

Then, the multi-way switching valve 20 is switched to a position at which the COM port (i.e., the common port 22) communicates with port No. 6 of the liquid feeding ports 24. During this process, the water sample in the groove sweeps across the sector area from port 6 to port 4. After the rotation reaches the port 6, the liquid feeding and discharging unit feeds the sampled water into the reaction unit 10 through the port 6.

Subsequently, as shown in fig. 27B, the multi-way switching valve 20 is switched to a position at which its COM port (i.e., the common port 22) communicates with No. 8 port on the left side. At this time, the liquid sampling and delivering unit samples water through the port 8 of the multi-way switching valve 20, and the water sample fills the groove between the COM port and the port 8.

Then, the multi-way switching valve 20 is switched to a position at which the COM port (i.e., the common port 22) communicates with port No. 6 of the liquid feeding ports 24. During this process, the water sample in the groove sweeps across the sector area from opening 8 to opening 4. After the rotation reaches the port 6, the liquid feeding and discharging unit feeds the sampled water into the reaction unit 10 through the port 6.

Finally, the above-mentioned water samples, which are fed twice to the reaction unit 10, are discharged out of the water quality analyzer, for example, to a waste liquid tank 400 or other chemical equipment. This completes the cleaning operation of the residue of the multi-way switching valve 20.

Next, as shown in fig. 28A, the multi-way switching valve 20 is switched to a position in which its COM port (i.e., the common port 22) communicates with No. 5 port on the right side. At this time, the liquid feeding/withdrawing unit feeds the first reagent through the port No. 5 of the multi-way switching valve 20. Then, the multi-way switching valve 20 is switched to a position at which the COM port (i.e., the common port 22) communicates with port No. 6 of the liquid feeding ports 24. Thereby, the liquid feeding and taking unit feeds the first reagent into the reaction unit 10 through the port 6.

Similarly, as shown in fig. 28B, the multi-way switching valve 20 is switched to a position in which its COM port (i.e., the common port 22) communicates with port No. 7 on the left side. At this time, the liquid feeding/withdrawing unit feeds a second reagent (normally, a reagent different from the first reagent) through the port No. 7 of the multi-way switching valve 20. Then, the multi-way switching valve 20 is switched to a position at which the COM port (i.e., the common port 22) communicates with port No. 6 of the liquid feeding ports 24. Thereby, the liquid feeding and taking unit feeds the second reagent into the reaction unit 10 through the port 6. This process of loading the reagent can be repeated multiple times and the sequence can be varied, for example, by taking the solution through port 7 first, then taking the solution through port 5, and so on.

It can be understood that, in the present invention, it is preferable to dispose the liquid inlet port for the reagent between the liquid inlet port for the water sample and the liquid sending port, so that the fan area between the liquid inlet port for the water sample and the liquid sending port can be cleaned by the above-mentioned water sample cleaning method after the reagent sample introduction is completed. In other words, it is ensured that the area of the sector of the inlet port for the reagent to the feed port is smaller than the area of the sector between the inlet port for the sample of water and the feed port, or that the area of the sector of the inlet port for the reagent to the feed port is covered, in particular completely covered, by the area of the sector between the inlet port for the sample of water and the feed port.

Thus, according to the present invention, the inlet port for the reagent may be arranged circumferentially between the inlet port for the water sample and the liquid feeding port, and the inlet port for the reagent may be spaced from the inlet port and/or the liquid feeding port for the water sample, but may not be spaced, but arranged adjacently as shown in fig. 24. In the case where only one inlet port for a sample of water is provided, it should be ensured at least that the inlet port for the reagent or other liquid whose residue is liable to affect the measurement and analysis results is located between the only inlet port for the sample of water and the liquid feed port.

The influence of a comparative prior art water quality analyzer and a water quality analyzer according to the invention (i.e. a layout with a rotating sweep of the residues) on the measurement results is shown in the table below.

Table 2: comparison of the effects of the arrangement of the multi-way switching valve of the prior art and the multi-way switching valve of the present invention on the test results

The data in the table above is the effect of using two different rotary switching valve port arrangements on the silicon test results. The silicon was tested under the same test conditions with 20ug/L silicon as the standard and 30mg/L phosphorus added. The results clearly show that the concentration of silicon in the measured sample can be accurately measured (the error is less than 10%) by adopting the port arrangement mode of the rotary switching valve, and the error of the test result of silicon by adopting the conventional mode is nearly 1000%.

The above working steps can be repeated for a plurality of times to continuously realize the online monitoring of the water quality, the sequence of each working step can or cannot be exchanged according to the actual requirement, but the duration can be adjusted according to the specific requirement.

The specific embodiments described herein are merely illustrative of preferred embodiments and are not intended to limit the scope of the invention as defined by the claims that follow. Equivalent changes and modifications can be made by those skilled in the art according to the teachings of the present invention, and these changes and modifications fall within the scope of the present invention.

Claims

1. A water quality analyzer (100), comprising:

a liquid pick-up and delivery unit comprising:

a multi-way switching valve (20);

a flow path switching valve (40), the flow path switching valve (40) being switchable between a first position and a second position;

a pump (30), the pump (30) being arranged on a flow path between the multi-way switching valve (20) and the flow path switching valve (40);

a reaction unit (10), the reaction unit (10) being configured to contain a liquid to be fed, and including a first port (12) connected to the multi-way switching valve (20) and a second port connected to the flow switching valve (40),

wherein, in a liquid take-up state of the liquid take-up and delivery unit, the pump (30) is configured to draw the liquid toward the flow path switching valve (40) via the multi-way switching valve (20), and

wherein, in a liquid feeding state of the liquid taking and feeding unit, the flow path switching valve (40) is in the second position, so that the flow path switching valve (40), the pump (30), the multi-way switching valve (20) and the reaction unit (10) constitute a closed fluid circuit, whereby the pump (30) is configured to feed all or a part of the liquid extracted in the liquid taking state into the reaction unit (10) via the multi-way switching valve (20) and the first port (12), and gas in the reaction unit (10) flows to the flow path switching valve (40) via the second port (14).

2. A water quality analyzer according to claim 1 wherein said flow path switching valve (40) is in said first position communicable with the outside air in said liquid-taking state.

3. A water quality analyser as claimed in claim 2 wherein the multi-way switching valve (20) comprises an inlet port and a delivery port (24), the first port (12) being in fluid communication with the delivery port (24), in the take condition the pump (30) being configured to draw liquid from the inlet port via the multi-way switching valve (20) towards the flow switch valve (40), and in the delivery condition the pump (30) being configured to deliver all or part of the drawn liquid to the reaction unit (10) via the delivery port (24) and the first port (12).

4. A water quality analyzer according to claim 1 wherein the liquid is at least one of a water sample and a reagent, and the multi-way switching valve (20) includes an inlet port corresponding to the at least one.

5. A water quality analyser as claimed in claim 4 wherein the liquid is a sampled water and in the take liquid state the pump (30) is configured to draw the liquid from the inlet port via the multi-way switching valve (20) and the on-off flow valve (40) onto a flow path beyond the on-off flow valve (40) and in the send liquid state the pump (30) is configured to send the liquid on the flow path between the inlet port and the on-off flow valve (40) into the reaction unit (10).

6. A water quality analyser as claimed in claim 5 wherein in the liquid delivery state gas within the reaction cell (10) flows in the closed fluid circuit via the second port (14) towards the pump (30) to a position beyond the flow switch valve (40).

7. A water quality analyser as claimed in claim 4 wherein the liquid is a reagent and in the liquid-extraction state the pump (30) is configured to draw the liquid from the inlet port via the multi-way switching valve (20) onto a flow path between the multi-way switching valve (20) and the pump (30).

8. A water quality analyser according to any one of claims 1 to 7 wherein the multi-way switching valve (20) further comprises a common port (22), the common port (22) being capable of fluid communication with the inlet port in the liquid-withdrawing state and the common port (22) being capable of fluid communication with the liquid-delivery port (24) in the liquid-delivery state.

9. A water quality analyzer according to any of claims 1-7 wherein the pump (30) for taking and delivering liquid is constructed as a peristaltic pump capable of forward and reverse rotation.

10. A water quality analyser according to any one of claims 1 to 7 wherein the second port (14) of the reaction cell (10) is configured to be selectively vented to outside air via a third valve (60).

11. A method of delivering a fluid for a water quality analyzer (100), the water quality analyzer comprising:

a liquid pick-up and delivery unit comprising:

a multi-way switching valve (20);

a reaction unit (10), the reaction unit (10) being configured to contain a liquid to be fed in, and including a first port (12) connected to the multi-way switching valve (20) and a second port (14) connected to the flow switching valve (40);

the liquid taking and delivering method comprises the following steps:

-a liquid extraction step: switching the on-off flow valve (40) to the first position and pumping the liquid by the pump (30) through the multi-way switching valve (20) towards the on-off flow valve (40);

-a liquid feeding step: switching the flow switching valve (40) to the second position such that the flow switching valve (40), the pump (30), the multi-way switching valve (20), and the reaction unit (10) constitute a closed fluid circuit, and feeding all or a part of the liquid extracted in the liquid-extracting state into the reaction unit (10) by the pump (30) via the multi-way switching valve (20) and the first port (12), and causing the gas in the reaction unit (10) to flow to the flow switching valve (40) via the second port (14).

12. The method according to claim 11, wherein the pump (30) is a peristaltic pump, and in the liquid taking step, the liquid is drawn by rotating the peristaltic pump in the forward direction, and in the liquid feeding step, the liquid is fed into the reaction unit (10) by rotating the peristaltic pump in the reverse direction.

13. The liquid extracting and feeding method according to claim 11, wherein when the liquid is a water sample, in the liquid extracting step, the liquid is drawn from the liquid inlet port via the multi-way switching valve (20) onto a flow path beyond the flow path switching valve (40) by the pump (30), and in the liquid feeding step, the liquid between the liquid inlet port and the flow path switching valve (40) is fed into the reaction unit (10) by the pump (30).

14. The liquid extracting and feeding method according to claim 11, wherein when the liquid is a reagent, in the liquid extracting step, the liquid is extracted by the pump (30) through the multi-way switching valve (20) onto a flow path between the multi-way switching valve (20) and the pump (30).

15. An online water quality monitoring system, comprising a water quality analyzer (100) according to any one of claims 1-10 and at least one reagent reservoir, wherein the water quality analyzer (100) comprises an interface in fluid connection with a waste fluid reservoir (400) and the reagent reservoir, respectively.