EP4133254A1

EP4133254A1 - Spectrophotometry device and on-line analyser incorporating said device

Info

Publication number: EP4133254A1
Application number: EP21717070.3A
Authority: EP
Inventors: Bernard Munoz; Roger Delmas
Original assignee: Hydrale
Current assignee: Hydrale
Priority date: 2020-04-08
Filing date: 2021-04-07
Publication date: 2023-02-15
Also published as: FR3109218A1; WO2021204875A1; FR3109218B1

Abstract

Spectrophotometry device and on-line analyser incorporating said device The invention relates to a spectrophotometric analysis device (2) comprising: - a vessel (20) extending longitudinally along an axis (C), and having an inlet pipeline (231) for a sample, and an outlet pipeline (232) for the sample; - a first light source (241) configured to emit light radiation in the vessel (20) along the axis (C); - optical capturing means (26) configured to capture light radiation capable of passing through the vessel (20) along the axis (C); characterised in that the vessel (20) is made up of an assembly of at least one frame (210), a first optical cell (201), a second optical cell (202) and means for retaining (25) the first optical cell (201) and the second optical cell (202) on the frame (210).

Description

Spectrophotometry device and on-line analyzer incorporating this device

The field of the invention is that of the design and manufacture of devices for analyzing the quality of liquid media.

More specifically, the invention relates to a spectrophotometric analysis device suitable for carrying out various spectrometric methods and an on-line analyzer incorporating this spectrophotometric analysis device, suitable for analyzing the quality of liquid media, such as natural or treated water, possibly intended for consumption.

In the field of water treatment, increasingly stringent regulations concerning the admissible concentration thresholds in water oblige the development of new fully automated installations allowing on-line analysis, or in other words "continuous analysis", of several sample parameters of these waters, whether natural or industrial.

An on-line water analysis facility is described in the patent document published under the number FR2809490. This installation includes:

- means of taking a raw sample of the water to be analyzed;

- means for preparing the raw sample, for example with reagents and / or solvents, to produce a so-called "analyzable" sample;

- means of analyzing the sample. This type of installation conventionally comprises a control system for valves distributed throughout the installation to transfer various products (water, solvents, reagents, etc.) between the components of the installation, and allow automated analyzes.

The means of analysis are numerous and make it possible to obtain a wide variety of measurements of the components of water. For example, an analysis can be performed by UV or visible spectrophotometry, or by any other detection or separation method for liquid effluents, such as by refractometry, fluorescence, electrochemistry, conductivity, radioactivity, mass spectrometry, high performance liquid chromatography Or other.

Today the online systems on the market are systems aimed at specific analyzes, most often single-parameter. To have a set of analyzes as required in European regulations, it is therefore necessary to have several separate devices.

Such a quantity of analysis devices proves to be problematic for integration into an on-line analyzer, intended to be installed at the place where the samples are taken. Indeed, the total cost (purchase, maintenance and operating costs) of these devices can be prohibitive, and their integration into an online analyzer can be particularly complex due to the large number of hydraulic circuits, valves. , and different ways in which samples should be prepared for each analysis.

Another problem relates to the very nature of the analysis devices that are used. Indeed, these analysis devices may present designs derived from conventional devices used in the laboratory.

More specifically, the spectrophotometers used for on-line analyzes use cells which can be particularly expensive, in particular for quartz cells.

Carrying out on-line analysis, for example to monitor the water quality of a watercourse, may involve the installation of several analyzers, at the same places where samples are taken, along the watercourse. water. Consequently, the use of expensive components in the analysis means limits the number of analysis points that can be implemented by a structure.

The aim of the invention is in particular to overcome these drawbacks of the prior art. More specifically, the aim of the invention is to provide on-line water analysis equipment which is more suitable functionally and economically to be implemented in the field than the equipment according to the prior art.

The invention also aims to provide such equipment which is easy to maintain. These objectives, as well as others which will appear later, are achieved by the invention, which relates to a spectrophotometric analysis device comprising:

- a tank extending longitudinally along an axis C, and having an inlet pipe for a sample, and an outlet pipe for the sample;

- a first light source configured to emit light radiation in the tank along the C axis; - optical capture means configured to capture light radiation capable of passing through the tank along the C axis; characterized in that the tank consists of at least one assembly:

- a frame in which a recess for the circulation of the sample is made;

- a first optical cell removably mounted at a first end of the circulation recess;

- a second optical cell removably mounted at a second end of the circulation recess;

- Means for retaining the first optical cell and the second optical cell on the frame, the first optical cell and the second optical cell each comprising:

- a main body intended to form part of a reservoir delimited by the tank in which a sample is intended to take place for analysis, and

- a secondary body, the secondary bodies respectively forming the pipe of outlet or inlet duct, each main body comprising a bottom, and a peripheral wall extending from the bottom to an opening, the main bodies of the first and second optical cells being aligned on the C axis and oriented so that their respective openings face each other.

The spectrophotometric device according to the invention has a cell design that is particularly suitable for performing on-line analysis.

In fact, the vessel of the device is designed to allow spectrophotometric analysis along the length of the vessel. As a result, the device according to the invention benefits from high sensitivity, which is particularly advantageous for the on-line analysis of water, such as stream water or sea water. .

In addition, this sensitivity can be easily adjusted when assembling the vessel, by increasing or decreasing the length of the vessel.

The frame and its circulation recess make it possible to define the length of the cell, and thus of the optical path, and to define the sensitivity of the spectrophotometric device.

Changing the length of the tank is easily achievable by selecting a frame with a circulation recess of varying length. A greater length of the circulation recess increases the distance between the two optical cells and thus the distance (the optical path) between the optical cell bottoms.

Thanks to the invention, it is thus possible to obtain a cell with a particularly long optical path (for example 10 cm or more) without however requiring a single one-piece cell which is potentially expensive to manufacture and / or to procure. It suffices to use standardized optical cells for the device, and to install them in suitable racks to form cells with the desired optical path length, and in particular suitable for an on-line analysis, and even more specifically an on-line analysis. carried out in situ of natural water (streams, waste water, runoff water, ...).

The design of the device according to the invention is more particularly suitable for carrying out measurements in a natural environment, that is to say of liquids potentially saturated with gas, in particular with oxygen, and thus capable of causing the appearance of bubbles in the environment. the tank, and liquids also liable to cause significant and rapid clogging of the tank.

It should be noted that each of the optical cells is monobloc, or more precisely monolithic. Indeed, these optical cells are formed in a transparent material suitable for being crossed by the light rays produced by the first light source. For example, optical cells can be formed of quartz, or of glass. The design of the tank allows easy maintenance of the tank, which is a necessity for devices installed in the field with possibly delicate handling conditions.

For example, the cell parts can be decoupled to allow cleaning of the two optical cells and the circulation recess, or selective replacement of one of the cell components.

More specifically, the tank is formed only by the recess of the frame and by the two optical cells. Therefore, cleaning the tank is limited to cleaning these three elements. Optical cells are easy to clean. Indeed, they only have two hollow parts (the main body and the secondary body) which limits the possibilities of soiling and allows efficient cleaning to be carried out quickly. In particular, optical cells are not formed by an assembly of multiple small elements capable of forming multiple fouling points. According to a preferred design, the retaining means comprise:

- Positioning means, called first positioning means, of the first light source relative to the circulation recess;

- Positioning means, called second positioning means, optical capture means with respect to the circulation recess. Such retaining means have a dual function by making it possible, while keeping the first optical cell and the second optical cell captive in the circulation recess of the frame, to ensure the correct positioning of the first light source and the control means. optical capture.

In this case, according to an advantageous solution, the retaining means comprise: a first block assembled on the frame covering the first end of the circulation recess, the first block having one of the first positioning means and second positioning means;

- a second block assembled on the frame covering the second end of the circulation recess, the second block having the other of the first positioning means and the second positioning means.

Such blocks form a particularly simple solution for retaining optical cells on the frame within the circulation recess.

In addition, these blocks make it possible to close openings presented by the frame and intended to allow the insertion of the optical cells into the circulation recess and to prevent, or at the very least greatly limit, the passage of a light outside the device which would interfere with the spectrophotometric analysis.

As detailed below, the first positioning means and the second positioning means can take the form of recesses made. in the first block and the second block, thus constituting the locations where the first light source and the optical pickup means must be inserted.

Preferably, the first block and the second block are identical to each other.

In this way only one type of part must be manufactured to form a first block or a second block. The design of the device is thus simpler, practical and economical.

According to a preferred embodiment, the device comprises at least one source of emission of ultraviolet and / or visible radiation, the frame comprising positioning means, called third positioning means, of the source of emission of a ultraviolet and or visible radiation to emit ultraviolet and or visible radiation in one of the first or of the second optical cell, transversely to the C axis.

The source or sources of emission of ultraviolet and / or visible radiation make it possible to perform ultraviolet spectro-fluorimetry analyzes using the device.

The source (s) of emission of ultraviolet and / or visible radiation may be LEDs. They are then particularly advantageous for their performance, their lifespan and their cost. Other sources can be considered such as fiber sources.

Thanks to this embodiment, the positioning of the source (s) of ultraviolet and / or visible radiation is optimized and simplified by virtue of their integration into the frame.

According to a preferred design, the device comprises a second light source, the frame comprising positioning means, called fourth positioning means, of the second light source to emit light radiation in the tank along an axis A forming an angle between 40 ° and 50 ° with the C axis, and preferably an angle of 45 ° with the C axis.

With this design, it is possible to analyze a light signal emitted by the second light source, reflected by the sample located in the circulation recess.

Preferably, the fourth positioning means are configured to position the second light source so that it emits light radiation through the optical cell which is located below the optical capture means.

According to a preferred embodiment, when the first block and the second block are identical, the third positioning means and the fourth positioning means take the form of recesses presented by each of the first block and of the second block, and the device comprises shutters capable of being assembled on the recesses forming the third positioning means and the fourth positioning means.

These shutters allow the cell to have several recesses to increase the type of analysis that can be carried out by means of the device, while reserving a possibility to close one or more recesses when sensors or light sources are not assembled on these recesses.

The recesses can receive, indifferently, an optical fiber connection, an LED support, or a shutter. Thus equipped, a tank can have up to 6 optical inputs / outputs allowing a wide variety of optical configuration with a minimum number of sources and receivers.

Preferably, the circulation recess has a length greater than or equal to 30 millimeters, and advantageously greater than or equal to 50 millimeters and less than or equal to 100 millimeters. Such lengths of the tank allow it to give the spectrophotometric analysis device a sensitivity particularly suited to the measurement and on-line analysis of river water or marine water, for example. The length of the circulation recess is determined as a function of the expected concentrations in the medium to be analyzed. According to an advantageous characteristic, the device comprises, for each of the first light source and optical pickup means, means of optical fiber transmission of light radiation.

In this way, the spectrophotometric analysis device has a design that is particularly simple to implement. For example, the light source (s) can then include a generator of the radiation, an optical fiber extending from the generator, and a tip coupled to one end of the optical fiber. The generator can thus be easily removed from the tank and be coupled to it via the optical fiber and the tip which transmits the radiation back into the tank. According to an advantageous design, the device comprises sealing means between the first optical cell and the circulation recess, and between the second optical cell and the circulation recess.

Thanks to this design, although it has a modular design, the tank benefits from a reinforced seal. In fact, gaskets make it possible, for example, to ensure the tightness of the interior of the vessel, although the optical cells can be mounted and removed from the frame.

According to an advantageous characteristic, for each optical cell:

D ³ Se + 2. h with: - "D" is the internal section of the main body of the optical cell, measured perpendicular to the C axis;

- "Se" is the effective section of a collimating lens of the first light source; - "h" is the height along the axis C between the bottom of the main body of the optical cell and the secondary body of the optical cell which forms the inlet pipe or the outlet pipe.

In this way, interference is avoided between a light ray to be analyzed (corresponding to the effective section of the collimating lens) and any bubbles or dirt located in the corners of the tank, in particular at the periphery of the cell bottoms. optical.

This cell design thus avoids forming, or at the very least minimizes, trapping zones of microbubbles present in the fluid to be analyzed, and the accumulation of which can cause the formation of a bubble interfering with the optical ray, these latter forming in areas of disturbed flow (located particularly at the angles of the tank).

By internal section of the main body, it is understood the internal diameter of the main body in the case where the latter is cylindrical of revolution. According to an advantageous design, the device comprises an orientation support in the space of the vessel configured so that:

- the outlet pipe has a central extension axis E;

- the C axis of the tank and the central extension axis E are in a vertical plane; with the central extension axis E forming an angle b between 0 ° and 60 ° with a vertical direction V, preferably the angle b being between 0 ° and 45 °, the outlet pipe being arranged above the inlet pipe.

Thanks to this design, it is facilitated the evacuation of bubbles that have formed in the tank. The evacuation is better for an angle b between 0 ° and 45 °, and optimized for an angle b equal to 45 °. According to a first variant, the main body of each optical cell is cylindrical of revolution.

The flow in the tank is then facilitated, and the deposit of dirt in the corners of the tank is reduced.

According to a second variant, the main body of each optical cell has a square section.

In this way, optical transmission within the tank is favored.

The subject of the invention is also an online liquid analyzer, comprising:

- means for taking a raw sample of liquids;

- Means for preparing the raw sample comprising processing subassemblies, the preparation means being able to produce a sample to be analyzed;

electronic means for controlling the preparation means, the electronic means being configured with a plurality of protocols for preparing the sample to be analyzed from the raw sample with at least one of the sub- set of processing;

- means of spectrophotometric analysis of the sample to be analyzed; characterized in that the spectrophotometric analysis means comprise a spectrophotometric analysis device as described above. Through the use of a spectrophotometric analysis device as described above, the online analyzer according to the invention has a design particularly suitable for installation in the field.

Indeed, the on-line analyzer according to the invention then benefits from a spectrophotometric analysis device provided with a tank offering high sensitivity while not having an expensive design.

Consequently, on a site to be inspected, it is possible to multiply the number of on-line analyzers according to the invention without the multiplication of the number of spectrophotometric devices and, consequently, of the number of tanks, coming to encumber the cost. of all the installations. According to a preferred design, the preparation means comprise a syringe pump coupled to the sampling means, to the processing sub-assemblies, and to the means of analysis by spectrophotometry, via hydraulic circuits equipped with valves, the electronic means pilot valves are configured to open or close the valves according to the preparation protocols. Thanks to this design, the means of preparation are simplified compared to the means of preparation which exist in the prior art. The syringe pump has a reservoir in which the raw sample can be simply mixed with solvents or else in which reaction mixtures can be made.

The syringe pump thus forms a central element of the preparation means making it possible to take the components required with a view to the analyzes or to distribute the components and / or mixtures to the sub-set of the treatments with a view to carrying out intermediate preparations in order to finally be able to use them. inject into the means of analysis.

According to a preferred solution, the treatment sub-assemblies comprise thermoregulation means, oxidation means, micrometric filtration means, reserves of reagents, reserves of solvents.

Thanks to this design, the means of analysis by spectrometry make it possible to carry out different types of analyzes such as spectrophotometry by ultraviolet, or in the visible spectrum, by fluorescence, by colorimetry, or even Raman spectrometry. Other characteristics and advantages of the invention will emerge more clearly on reading the following description of two preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and of the appended drawings, among which: - Figure 1 is a schematic representation of a spectrophotometric analysis device and its tank, according to the invention, more specifically illustrating the tank according to a first cross section;

- Figure 2 is a schematic representation in a view identical to that of Figure 1, of a frame and retaining means participating in the assembly of the vessel of the spectrophotometric analysis device according to the invention;

- Figure 3 is a schematic representation of the spectrophotometric analysis device according to the invention, more specifically illustrating the cell in a second cross section perpendicular to the first cross section; - Figure 4 is an exploded schematic representation according to the second cross section, of the frame as well as a first block and a second block of the retaining means;

- Figure 5 is a schematic representation in a perspective view of a first optical cell of a spectrophotometric analysis device according to the invention; - Figure 6 is a schematic representation of the first optical cell according to the section plane of Figure 3;

- Figure 7 is a schematic representation of an online liquid analyzer according to the invention;

- Figure 8 is a schematic representation in a perspective view of a tank according to a second embodiment;

- Figure 9 is a schematic representation in cross section of the tank according to the second embodiment, in particular along the section lines IX-IX illustrated in Figure 10;

FIG. 10 is a schematic representation according to a transverse section of the tank according to the second embodiment, in particular according to the section lines X-X illustrated in FIG. 10;

- Figure 11 is a schematic representation in a top view of the tank, illustrating in particular a second block of retaining means;

- Figure 12 is a schematic representation of the tank according to the second embodiment coupled to a support for orientation in space;

- Figure 13 is a schematic representation of an optical cell according to another embodiment.

With reference to FIGS. 1 to 6, and 8 to 13, a spectrophotometric analysis device 2 is described below. The spectrophotometric analysis device 2 is designed to make it possible to perform a spectrometric measurement of the absorbance of a solution at a given wavelength, or over a given region of the light spectrum. As illustrated schematically by Figures 1 and 3, the spectrophotometric analysis device 2 comprises:

- a tank 20;

- a first light source 241;

- optical capture means 26.

Conventionally in the field of spectrophotometry, the first light source 241 is configured to emit light radiation in the tank 20. This light radiation emitted in the tank is produced at a given wavelength or in a given region of the spectrum. luminous.

The optical pickup means 26 are for their part configured to pick up a light radiation capable of passing through the tank 20.

Referring to Figures 1 and 3, and Figures 9 and 10, the tank 20 extends longitudinally along an axis C.

For example, the tank 20 can take the form of a cylinder, and in particular of a cylinder of revolution.

The tank 30 can also take the form of a straight block of square section.

The first light source 241 and the optical pickup means 26 are more specifically configured to emit radiation and to pick up radiation along the C axis respectively.

To this end, and as detailed below, the first light source 241 and the optical pickup means 26 are located in alignment with the C axis.

Referring to Figures 3, 9 and 12, the tank 20 has an inlet pipe 231 for a sample and an outlet pipe 232 for the sample.

A liquid sample is intended to be introduced into the tank 20 via the inlet pipe 231 for carrying out a spectrophotometric analysis, then discharged via the outlet pipe 232 once the analysis has been carried out. .

The first light source 241 and the optical capture means 26 thus make it possible to perform a spectrophotometric absorption measurement of the sample located in the tank 20.

The device 2 according to the present embodiment also comprises two sources of emission of ultraviolet and / or visible radiation 243 configured to emit ultraviolet and / or visible radiation in the tank 20. The ultraviolet and / or visible radiation is advantageously emitted. transversely to the C axis.

The device 2 also comprises a second light source 242 configured to emit light radiation in the tank 20 along an axis A distinct from the axis C. Preferably, the axis A forms an angle a of between 40 ° and 50 ° with axis C.

Preferably, this angle α is 45 ° with the axis C. The two sources of emission of ultraviolet and / or visible radiation 243 make it possible to carry out fluorescence spectroscopy measurements, and the second light source 242 makes it possible to carry out a spectrophotometric measurement of a light signal reflected inside. the tank 20, and more specifically making it possible to determine the nature of the particles contained in the sample.

More generally, the light sources of the spectrophotometric analysis device 2 make it possible to perform an analysis in a measurement range covering the ultraviolet spectrum, as well as the visible spectrum, that is to say between 200 and 1000 nanometers. These components (light sources and sources of emission of ultraviolet and / or visible radiation) are described in more detail below.

The device 2, according to the present embodiment, comprises for each of the first light source 241 and optical pickup means 26, optical fiber transmission means of light radiation. The device 2 also comprises, for the second light source 242, means for transmitting light radiation by optical fiber.

To this end, these components include an optical fiber provided with a tip intended to cooperate with the tank 20.

More precisely, and with reference to FIGS. 1 and 3, the optical pickup means 26 comprise a first end piece 260, a first optical fiber 261, and a unit for analyzing the light radiation 262. The first optical fiber 261 extends to from the light radiation analysis unit 262, and the first tip 260 is coupled to one end of the first optical fiber 261.

Similarly, the first light source 241 comprises a second end piece 2411, a second optical fiber 2412, and a first unit for emitting light radiation 2413. The second optical fiber 2412 extends from the first unit for emitting. of light radiation 2413, and the second tip 2411 is coupled to one end of the second optical fiber 2412.

More specifically and as illustrated in Figure 13, the second tip 2411 of the first light source 241 comprises a collimating lens 24110.

This 24110 collimating lens is centered on the C axis by a 24111 positioning ring.

The collimating lens 24110 has an effective section Se which corresponds to the diameter of the circle delimiting the hemisphere not masked by the system for maintaining / positioning the collimating lens, ie the positioning ring.

For measurement purposes, the effective section Se of the collimating lens 24110 can be assimilated to the internal diameter of the positioning ring 2411. Indeed, the collimating ring positioning 24111 prevents the transmission of light radiation through its material.

Also, with reference to Fig. 3, the second light source 242 comprises a third end piece 2421, a third optical fiber 2422, and a second unit for emitting light radiation 2423. The third optical fiber 2422 extends from the second light emitting unit 2423, and the third tip 2421 is coupled to one end of the third optical fiber 2421.

Referring to Figures 1 to 4, and Figures 8 to 11, and according to the principle of the invention, the tank 20 is constituted by an assembly of at least: - a frame 210;

- a first optical cell 201;

- a second optical cell 202;

- Retaining means 25 of the first optical cell 201 and of the second optical cell 202 on the frame 210. The frame 210 includes a recess 203 for circulation of the sample. More specifically, a sample is intended to enter the circulation recess 203 through the inlet line 231, and then exit through the outlet line 232.

The frame 210, which forms the wall of the circulation recess 203, is made of a material compatible with the use of organic solvents and acids. The material constituting this frame is also opaque so as to prevent the entry of light from outside the device which could interfere with the analysis.

By way of non-limiting example, this material can be tetra-fluoroethylene.

As illustrated by Figures 2 and 4, and 9 and 11, this circulation recess 203 passes longitudinally through the frame 210. This circulation recess 203 has a first end 2031 and a second end 2032 opposite the first end 2031 along of axis C.

According to the principle of the invention, and with reference to FIGS. 1 to 6, the first optical cell 201 is removably mounted at the first end 2031 of the circulation recess 203. Likewise, the second optical cell 202 is mounted. removably at the second end 2032 of the circulation recess 203.

The retaining means 25 allow the optical cells to be held captive in the circulation recess 203.

According to the two embodiments, these retaining means 25 comprise:

- a first block 211 assembled on the frame 210 covering the first end 2031 of the circulation recess 203;

- a second block 212 assembled on the frame 210 covering the second end 2032 of the circulation recess 203. To assemble the first block 211 and the second block 212 on the frame 210, and with reference to Figures 1, 2 and 8 to 11, the retaining means 25 also include:

- Tapped holes 251 presented by the frame 210;

- additional screws 250 in assembling the tapped holes. Referring to Figures 1 to 4, and 8 to 11 to ensure the proper functioning of the light sources and optical capture means 26, the device 2 comprises positioning means integrated in the tank 20.

More specifically, the retaining means 25 comprise first positioning means 2410 of the first light source 241 relative to the circulation recess 203.

These first positioning means 2410 take the form of a recess presented by the second block 212. This recess is centered on the axis C and is more specifically intended to receive, orient in the direction of the tank 20 on the axis C, and maintaining in position the second end piece 2411 of the first light source 241. The recess forming the first positioning means 2410 can receive the positioning ring 24111 of the collimating lens 24110 mentioned above. However, according to one possible embodiment, the positioning ring 24111 can be formed directly from the first block 211 or the second block 212 and in this case the positioning ring 24111 is integral with said block.

Likewise, the retaining means 25 comprise positioning means, called second positioning means 2600, optical capture means 26 with respect to the circulation recess 203.

These second positioning means 2600 also take the form of a recess centered on the axis C. This recess is presented by the first block 211 and is more specifically intended to receive, orient in the direction of the tank 20 on the axis C , and hold in position the first end piece 260 of the optical pickup means 26.

According to the present embodiment and with reference to Figures 1, 2, and 8 to 10, the device 2 also comprises third positioning means 2430 of the sources of emission of ultraviolet and / or visible radiation 243.

The third positioning means 2430 take the form of recesses made in the first block 211 for the first embodiment illustrated by FIG. 2, and in the first block as well as in the second block 212 for the second embodiment illustrated by FIGS. 8 to 10. These recesses extend perpendicularly to the axis C at the level of one of the ends 2031, 2032 of the circulation recess 203. The sources of emission of ultraviolet and / or visible radiation 243 are intended to be introduced and held in position in these recesses by screwing. According to Figures 3, 4, and 8 to 11, the device 2 also comprises fourth positioning means 2420 of the second light source 242.

The fourth positioning means 2420 are for their part, with reference to the embodiment of FIG. 4, presented by the first block 211 of the retaining means 25. According to the second embodiment illustrated by FIGS. 8 to 11, the fourth positioning means 2420 are presented both by the first block 211 and by the second block 212.

These fourth positioning means 2420 each take the form of a recess formed in the first block 211 and / or the second block 212. This recess extends lengthwise along an axis, in particular the axis A shown in FIGS. 3, 4 and 9, which forms an angle a between 40 ° and 50 ° with the axis C.

According to the embodiment of the tank 20 illustrated by Figures 8 to 11, the first block 211 and the second block 212 are identical to each other.

More specifically and with reference to Figures 9 and 10, the first block 211 and the second block 212 are symmetrical with respect to a plane P perpendicular to the central axis C.

This first block 211 and this second block 212 can thus be interchanged or be replaced by identical parts.

Only one type of block needs to be fabricated to form the first block 211 or the second block 212.

As mentioned above, the first block 211 and / or the second block 212 have recesses intended to form the first positioning means 2410, the second positioning means 2600, the third positioning means 2430, and the fourth positioning means. 2420. Thanks to the symmetry of the two blocks 211, 212, the recesses can be used indifferently to form one of the positioning means mentioned above and adapted to the position of these recesses. This design of the blocks 211, 212 thus offers significant versatility to the tank 20.

According to this embodiment illustrated by FIGS. 8 to 11, the device 2 also comprises shutters which can be assembled on the recesses forming the third positioning means 2430 and the fourth positioning means 2420.

These shutters 6 are assembled on the recesses as soon as the latter are not used to position a light source and or any other device capable of being assembled in one of these recesses.

Thanks to this embodiment, the device 2 can also be adapted to different measurement requirements. That is to say that the various recesses can receive other optical sources, in visible light or in UV, or other means of capture. optical. Switching systems can then be used to vary the type of measurement that can be carried out at a given time in the tank.

This symmetry of the optical blocks and of the various recesses thus offers a particularly advantageous parameterization capacity for the device 2. Now, with reference to FIGS. 5, 6 and 13, the optical cells (first optical cell 201, and second optical cell 202) are described.

The second optical cell 202 is identical to the first optical cell 201. Its structure is thus identical to that of the first optical cell and the following description of the first optical cell 201 also corresponds to a description of the second optical cell.

The first optical cell 201 presents:

a main body intended to form part of the reservoir delimited by the tank 20 and in which a sample is intended to take place in order to be analyzed therein;

- a secondary body extending perpendicular to the main body from the latter.

The secondary body opens into the main body to allow fluid communication between them.

According to the first embodiment illustrated in Figure 3, the secondary body of the first optical cell 201 is intended to form the outlet pipe 232 of the sample. For the second optical cell 202, the secondary body is intended to form the inlet pipe 231 for the sample.

According to the second embodiment illustrated in Figure 9, the secondary body of the first optical cell 201 is intended to form the inlet pipe 231 of the sample.

For the second optical cell 202, the secondary body is intended to form the outlet pipe 232 of the sample.

More specifically, according to Figures 5, 6 and 13, the main body of the first optical cell 201 comprises a bottom 2010, and a peripheral wall 2011 extending from the bottom 2010 to an opening 2013. According to the embodiment in FIG. 5, the main body takes the form of a cylinder, and in particular of a cylinder of revolution. It is, however, conceivable that the main body take the form of a straight paving stone with a square section.

The secondary body in turn has a cylindrical wall 2014 extending from the peripheral wall 2011 of the main body to a second opening 2015.

The main body is open to the secondary body, that is to say that, as illustrated by Figures 6 and 13, fluid circulation from the secondary body into the main body is possible at the junction between the two. body.

According to the present embodiment, the optical cells are made of quartz.

Of course, the optical cells can be made from any other type of suitable material. For example, optical cells can be made of glass.

Other types of transparent material capable of passing light radiation can be used.

Referring to Figure 6, the first optical cell 201 has an internal section D (its diameter given that according to the present embodiment the main body is cylindrical of revolution) at the level of the main body which is between 5 and 7 mm , or even between 5 and 6 millimeters.

This internal section D is measured perpendicular to the axis C, and between the internal faces of the peripheral wall 2011 of the main body. The inlet pipes 231 and the outlet pipes 232 have an internal diameter d of between 2 and 3 millimeters.

Referring to Figure 13, the secondary body is connected to the main body in the immediate vicinity of the bottom 2010.

More precisely, each optical cell 201, 202 has a height h, along the axis C, between the bottom 2010 of the main body of the optical cell 201, 202 and the secondary body of the optical cell 201, 202 which forms the inlet pipe or outlet pipe. This height h is measured between an internal face of the bottom 2010 of the main body, and an internal face of the cylindrical wall 2014 of the secondary body closest to the bottom 2010, as illustrated by FIG. 13. It should be noted that , according to one characteristic of the invention, the following ratio is observed by each optical cell: D> Se + 2. h.

In other words, the internal section (or internal diameter if applicable) of the tank 20 is at least equal to the effective section Se of the collimating lens 24110 plus twice the height h of the junction zone between the bottom 2010 of the main body and the cylindrical wall 2014 of the secondary body.

As an indication, the positioning ring may have an internal diameter of 3mm and the height h is less than 2mm and preferably less than or equal to 1mm.

In the vessel 20, the first optical cell 201 and the second optical cell 202 are opposed to each other in the circulation recess 203. In other words, the main bodies of these optical cells 201, 202 are aligned on the axis C and oriented in such a way that their respective openings face each other, and that their bottom is located in contact with the retaining means 25.

To prevent any leakage of the liquid sample during its analysis and its passage through the circulation recess 203, the device 2 according to the invention also comprises sealing means between the first optical cell 201 and the recess of circulation 203, and between the second optical cell 202 and the circulation recess 203.

These sealing means take for example, with reference to Figures 9 and 10, the form of O-rings 7. These O-rings are in particular Teflon-coated O-rings. The dimensions of the space in which the sample circulates in the tank is defined by the circulation recess 203 as well as by the first optical cell 201 and the second optical cell 202 held captive in the circulation recess 203.

According to a preferred embodiment, the circulation recess 203 (or more precisely the space in which the sample circulates to be analyzed) has a length greater than or equal to 30 millimeters. Advantageously, the length of the tank 20 is greater than or equal to 50 millimeters and less than or equal to 100 millimeters.

Of course, depending on the desired dimensions of the circulation recess 203, the length of the tank 20 can be adapted. The tank 20 preferably has a maximum volume of less than 0.5 milliliter. Such a maximum volume allows device 2 to perform an analysis on a sample with a volume of less than 1 milliliter.

With reference to FIG. 12, the device 2 also comprises an orientation support 27 in the space of the tank 20. This orientation support 27 is designed to position the tank 20 in a predetermined manner in the space, and in particular in relation to the vertical of the place of installation of the device 2.

As illustrated by FIG. 12, a vertical direction V is shown and the position of the tank 2 with respect to this vertical direction V is maintained thanks to the orientation support 27.

With reference to this figure, the outlet pipe 232 has a central extension axis E. This central extension axis E corresponds to the axis along which extends the secondary body of the optical cell which forms the line of outlet 232. This central extension axis E is perpendicular to the axis C. The orientation support 27 is configured so that:

- The axis C of the tank 20 and the central extension axis E are in a vertical plane, the vertical direction V shown falling of course in said vertical plane;

- the central extension axis E forms an angle b between 0 ° and 60 ° with the vertical direction V, preferably the angle b being between 0 ° and 45 °; - the outlet pipe 232 is arranged above the inlet pipe 231.

According to the present embodiment, the angle b is 45 °.

Now, with reference to the block diagram illustrated in Figure 7, an in-line liquid analyzer 1, according to the invention, is described.

The analyzer 1 comprises: - means 3 for taking a raw sample EB of the liquids;

- means 4 for preparing the raw sample EB to produce a sample to be analyzed EA;

- Electronic means 5 for controlling the preparation means 4; means for spectrophotometric analysis of the sample to be analyzed EA, the means for analysis by spectrophotometry comprising the device 2 for spectrophotometric analysis described above.

Analyzer 1 also includes means of control and access to the spectrometric resource.

The sampling means 3 are designed to be able to take, as soon as necessary, a predetermined quantity of a liquid to be sampled at the place of installation of the analyzer 1 online.

The preparation means 4 include processing subassemblies 41 as well as a syringe pump 40.

The syringe pump 40 is coupled to the sampling means 3, to the processing sub-assembly 41 and to the spectrophotometric analysis means, via hydraulic circuits 42.

The hydraulic circuits 42 include valves 43 which can be actuated by the electronic control means 5.

Alternatively, the valves 43 can take the form of a multi-way valve system.

Indeed, the electronic control means 5 are coupled to the pump-syringe 40 as well as to the hydraulic circuit 42 and more specifically to the valves 43. The electronic control means 5 are configured to open or close the valves 43 according to protocols. preparation 50.

The syringe pump 40 forms a central element of the preparation means 4.

In fact, this single syringe pump 40 makes it possible to withdraw and / or inject liquids.

The actuation of the valves 43 of the hydraulic circuits 42 makes it possible, concomitantly with the actuation of the syringe pump 40, to select the source (s) of the liquids taken by the syringe pump 40 or the destinations of these liquids during an injection. by the syringe pump 40.

As explained previously, 50 preparation protocols are implemented.

Indeed, the electronic means 5 are configured with preparation protocols 50 of the sample to be analyzed from the raw sample EB with at least one of the processing subsets 41.

More precisely, the electronic control means 5 comprise a memory in which are programmed preparation protocols 50 describing the operations that a raw sample must undergo in order to be able to be analyzed according to a desired analysis, and which is intended to be carried out by the device 2 analysis.

A controller of these electronic control means 5 is coupled to the memory in order to be able to apply one of these protocols and to control the valves 43 and the syringe pump 40 as indicated in the preparation protocol 50 which must be executed. According to the present embodiment, the treatment sub-assemblies 41 comprise thermoregulation means 411, oxidation means 412, micrometric filtration means 413, reserves of reagents 414, reserves of organic solvents 415a, and reserves of ionic solvents 415b. The micrometric filtration means 413 are, according to the present embodiment, interposed directly between the sampling means 3 and the syringe pump 40, according to the direction of movement of the fluid to be analyzed.

These micrometric filtration means 413 make it possible to achieve filtration with a cutoff threshold of less than one micrometer, and ideally with a cutoff threshold of 0.45 micrometer.

The various processing sub-assemblies 41 make it possible to carry out various preparation combinations in order to obtain a sample to be analyzed EA.

For example, reagent reserves 414 can include colorimetric reagents. The use of one of these colorimetric reagents in combination with the thermoregulation means 411 can allow the sample to be heated in such a way as to allow the development of a chemical colorimetric reaction.

The processing subassemblies 41 can also include:

- a concentrator on solid liquid phase as described in the patent document published under the number FR2809490 to implement protocols for low pressure chromatographic separations of organic or ionic products.

- organic matter mineralization systems to allow the analysis of organic fractions of certain elements (P, N, ...) based for example on chemical oxidation and / or UV radiation.

As explained above, the syringe pump 40 forms a central element of the preparation means 4.

With reference to FIG. 7, the syringe pump 40 comprises a reservoir 400, a piston 401 and a motor 402. The motor 402 makes it possible to modify the position of the piston 401 in order to increase or decrease the volume of the reservoir 400. This motor 402 is controlled by electronic means 5. The reservoir 400 of the syringe pump 40 thus serves as a reaction system making it possible to mix the sample with one or more solvents, or else to prepare a reaction mixture.

Once the sample to be analyzed EA is prepared, it is injected from the reservoir 400 of the pump-syringe 40 into the analysis device 2 where, thanks to its vessel 20, a plurality of analyzes can be carried out sequentially.

The on-line liquid analyzer 1 thus makes it possible on its own to provide a set of water quality parameters which are frequently sought after, and which can only be obtained conventionally using a plurality of water quality parameters. 'devices. For example, the analyzer 1 according to the invention makes it possible, thanks to its spectrophotometric analysis device 2, to detect dissolved materials such as nutrients (nitrate, ammonium, nitrite, phosphate, silicate, urea, etc.), organic matter (estimate of dissolved organic carbon by ultraviolet spectrum analysis), dissolved organic nitrogen, dissolved organic phosphorus, and polycyclic aromatic hydrocarbons (through fluorescence), chlorophyll pigments (also through fluorescence), various groups of pesticides, also different groups of non-fluorescent or weakly fluorescent organic micropollutants (phenol, etc.), and also metals such as cadmium. Depending on the analyzes that one wishes to carry out with the analyzer 1, the length of the vessel of the spectrophotometric analysis device 1 can be adapted. For example, a tank with a length of 10cm allows an analysis of nitrates in the marine environment.

Analyzer 1 also enables the detection of particulate matter through turbidity measurements, as well as characterization of the nature of the particular matter through spectral analysis during lateral scattering of exciting light. (via the sources of emission of ultraviolet and / or visible radiation 243).

The analyzer 1 according to the invention is designed to perform these various measurements in time-sharing, of all the possible parameters at a low analysis frequency. The analyzer 1 according to the invention is particularly advantageous for measurement and analysis applications on natural and industrial water networks, owing to the fact that it allows both analyzes at frequencies high enough to succeed in detecting various types of pollution, and a measurement of other essential parameters which are not conventionally measured online (total phosphorus and nitrogen), at a competitive price compared to conventional online analyzers.

Analyzer 1 is particularly advantageous in that it allows easy circulation of fluids and supports a variety of spectrophotometric analysis methods.

Unlike the devices according to the prior art which carry out single-parameter analyzes at very high frequency, the device 2 and the analyzer 1 according to the invention allow the realization of low-frequency multiparametric analyzes, particularly suitable for measurements on networks. measurements where a frequency of a few measurements per day is sufficient with regard to the temporal evolution of the parameters.

Device 2 and analyzer 1 are also particularly suited to conflicting constraints relating to optical path lengths, contamination of the measurement medium, and interference between analyzes.

More specifically, the device 2 and the analyzer 1 are particularly suitable for directly analyzing a non-degassed liquid in a natural environment.

Claims

1. Spectrophotometric analysis device (2) comprising:

- a tank (20) extending longitudinally along an axis (C), and having an inlet pipe (231) for a sample, and an outlet pipe (232) for the sample;

- a first light source (241) configured to emit light radiation in the tank (20) along the axis (C);

- optical capture means (26) configured to capture light radiation capable of passing through the tank (20) along the axis (C); characterized in that the tank (20) is constituted by an assembly of at least:

- a frame (210) in which is formed a circulation recess (203) for the sample;

- a first optical cell (201) removably mounted at a first end (2031) of the circulation recess (203); - a second optical cell (202) removably mounted at a second end (2032) of the circulation recess (203);

- Retaining means (25) of the first optical cell (201) and of the second optical cell (202) on the frame (210), the first optical cell (201) and the second optical cell (202) each comprising:

- a main body intended to form part of a reservoir delimited by the tank (20) in which a sample is intended to take place for analysis, and

- a secondary body, the secondary bodies respectively forming the outlet pipe (232) or the inlet pipe (231), each main body comprising a bottom, and a peripheral wall extending from the bottom to an opening, the main bodies of the first and the second optical cell (201, 202) being aligned with the axis C and oriented so that their respective openings face each other. 2. Device (2) according to the preceding claim, characterized in that the retaining means comprise:

- positioning means, called first positioning means (2410), of the first light source (241) relative to the circulation recess

(203); - positioning means, called second positioning means

(2600), optical capture means (26) relative to the circulation recess (203).

3. Device (2) according to the preceding claim, characterized in that the retaining means (25) comprise:

- a first block (211) assembled on the frame (210) covering the first end (2031) of the circulation recess (203), the first block (211) having one of the first positioning means (2410) ) and second positioning means (2600);

- a second block (212) assembled on the frame (210) covering the second end (2032) of the circulation recess (203), the second block (212) having the other of the first positioning means (2410) ) and second positioning means (2600).

4. Device (2) according to the preceding claim, characterized in that the first block (211) and the second block (212) are identical to each other.

5. Device (2) according to any one of the preceding claims, characterized in that it comprises at least one source of emission of ultraviolet and / or visible radiation (243), the device (2) comprising positioning means, called third positioning means (2430), of the source of emission of ultraviolet and / or visible radiation (243) in order to emit ultraviolet and / or visible radiation in one of the first or of the second optical cell (201, 202), transversely to the axis (C). 6. Device (2) according to any one of the preceding claims, characterized in that it comprises a second light source (242), the device (2) comprising positioning means, called fourth positioning means (2420), of the second light source (242) to emit light radiation in the tank (20) along an axis (A) forming an angle (a) of between 40 ° and 50 ° with the axis (C), and preferably an angle 45 ° with the axis (C).

7. Device (2) according to claims 4, 5 and 6, characterized in that the third positioning means (2430) and the fourth positioning means (2420) take the form of recesses presented by each of the first block (211 ) and of the second block (212), and in that it comprises shutters (6) capable of being assembled on the recesses forming the third positioning means (2430) and the fourth positioning means (2420).

8. Device (2) according to any one of the preceding claims, characterized in that the circulation recess (203) has a greater length or equal to 30 millimeters, and advantageously greater than or equal to 50 millimeters and less than or equal to 100 millimeters.

9. Device (2) according to any one of the preceding claims, characterized in that it comprises, for each of the first light source (241) and optical pickup means (26), optical fiber transmission means of radiation. luminous.

10. Device (2) according to any one of the preceding claims, characterized in that it comprises sealing means between the first optical cell (201) and the circulation recess (203), and between the second cell. optic (202) and the circulation recess (203).

11. Device (2) according to any one of the preceding claims, characterized in that for each optical cell (201, 202):

D ³ Se + 2.h with:

- "D" is the internal section of the main body of the optical cell (201, 202), measured perpendicular to the axis (G);

- "Se" is the cross section of a collimating lens of the first light source (241);

- "h" is the height along the axis C between the bottom of the main body of the optical cell (201, 202) and the secondary body of the optical cell (201, 202) which forms the inlet pipe or the outlet pipe.

12. Device (2) according to any one of the preceding claims, characterized in that it comprises an orientation support (27) in the space of the tank (20) configured so that:

- the outlet pipe (232) has a central extension axis (E);

- the axis (C) of the tank (20) and the central extension axis (E) are in a vertical plane; with the central extension axis (E) forming an angle b between 0 ° and 60 ° with a vertical direction (V), preferably the angle b being between 0 ° and 45 °, the outlet pipe (232 ) being disposed above the inlet pipe (231).

13. In-line liquid analyzer (1), comprising:

- sampling means (3) of a raw sample (EB) of the liquids;

- Preparation means (4) of the raw sample (EB) comprising processing subassemblies (41), the preparation means (4) being able to produce a sample to be analyzed (EA); - electronic means (5) for controlling the preparation means, the electronic means (5) being configured with a plurality of preparation protocols (50) of the sample to be analyzed (EA) from the raw sample (EB ) with at least one of the processing subsets (41); - means of spectrophotometric analysis of the sample to be analyzed; characterized in that the spectrophotometric analysis means comprise a spectrophotometric analysis device (2) according to any one of the preceding claims.

14. On-line analyzer (1) according to the preceding claim, characterized in that the preparation means (4) comprise a syringe pump (40) coupled to the sampling means (3), to the subassemblies (41) of treatment. , and to analysis means (2) by spectrophotometry, via hydraulic circuits (42) equipped with valves (43), the electronic control means (5) being configured to open or close the valves (43) in depending on the preparation protocols (50).

15. On-line analyzer (1) according to any one of claims 13 and 14, characterized in that the processing subassemblies (41) include:

- thermoregulation means (411);

- means of oxidation (412); - micrometric filtration means (413);

- reserves of reagents (414);

- solvent reserves (415a, 415b).