Device for analysing a fluid comprising a probe head

Abstract

The invention relates to a device for analysing a fluid, the device comprising a probe body (110) that is generally elongate along a longitudinal axis, the probe body being configured so as to be impermeable to the fluid; a probe head (120) forming a projection extending from one end of the probe body (110) and arranged so as to be submerged in the fluid, wherein the probe head comprises a plurality of detection surfaces (121), and wherein each detection surface comprises an arrangement of electrodes (123) configured to generate electrical signals representative of fluid parameters through contact with the fluid; and an analogue interface board (130) arranged inside the probe body and configured to receive the electrical signals generated by the electrode arrangements (123) of all the detection surfaces (121) and transmit them to a processing unit external to the device.

Description

Device for analyzing a fluid comprising a probe head Background of the invention

[0001] The present description relates to a device for fluid analysis. In particular, the present description relates to a device for water analysis.

[0002] Fluid analysis is important in many situations, particularly in the field of water quality control in distribution networks. In particular, it is often necessary to perform a set of different tests within the same water flow, for example to detect several physical or chemical parameters (pH, conductivity, temperature, chlorine concentration).

[0003] For this purpose, it has been proposed to assemble several sensors within the same device in order to measure different parameters of a fluid. In particular, [REF 1] proposes an analysis device whose sensitive part comprises several electrodes deposited on a rigid substrate provided with electrodes allowing various measurements of parameters in the water.

[0004] Furthermore, [REF 2] proposes a biological fluid analysis device comprising several electrochemical sensors deposited on a polycarbonate substrate.

[0005] However, integrating a large number of electrodes into the sensor involves increasing the surface area of ​​the sensitive part of the sensor and therefore generally increasing the size of the sensor, which is not preferable.

[0006] There is therefore a need to address the state-of-the-art issues.

[0007] References [REF 1] US 2021 / 0123875 Al [REF 2] RITTER, Christoph, HEIKE, Frebel, HERBERT, Kroneis, et al. Multi para meter miniaturized sensor arrays for multiple use. Sensors and Actuators B: Chemical, 2001, vol. 76, no. 1-3, p. 220-225. [REF 3] US 2021 / 0130540 Al Subject matter and summary of the invention

[0008] This description aims to remedy at least in part these drawbacks.

[0009] For this purpose, the present description relates to a device for analyzing a fluid, comprising a probe body of generally elongated shape along a longitudinal axis, the probe body being configured to be impermeable to the fluid; a probe head forming a protrusion extending from one end of the probe body and arranged to be immersed in the fluid, the probe head comprising several detection surfaces, in which each detection surface comprises an arrangement of electrodes configured to be sensitive to parameters of the fluid by contact with the fluid;and an analog interface board disposed within the probe body and electrically connected to the electrode arrangements of all the sensing surfaces and configured to exchange electrical signals with the electrode arrangements, wherein the electrode arrangement of each sensing surface is deposited on a substrate, said substrate being fixed on the protrusion formed by the probe head; wherein the analog interface board is unique and is electrically connected to all the electrode arrangements via an interfacing circuit into which ends of all the substrates are inserted.;

[0010] In the present description, the analog interface card is a printed electronic circuit configured to interface with the electrodes of the analysis device. Such an interface is also sometimes referred to by its English name: “analog front-end” or “analog front-end board”. In the present description, the electrical signals are electrical signals representative of the parameters of the fluid to which the electrode arrangements are sensitive, these signals can be transmitted by the analog interface card to a processing unit external to the device.

[0011] In the present description, an electrode arrangement is a set of sensitive elements each comprising at least one conductive element called an electrode, optionally coupled with one or more other conductive, semiconductive or insulating materials. These electrode arrangements, optionally coupled to materials, are configured so that, in contact with a fluid, their electrical or electromagnetic properties change according to the physical or chemical properties of the fluid.

[0012] With the present invention, it is possible to maximize the number of detection surfaces in the probe head while keeping the size and volume of the probe head substantially constant.

[0013] The present invention therefore makes it possible to obtain sensors with a greater density of electrodes. It is thus possible to detect numerous parameters in a fluid without increasing the size of the fluid analysis device.

[0014] In addition, the present invention makes it possible to limit the increase in complexity of the device by not multiplying the analog interface cards. In particular, it is possible to use a single analog interface card to interface with several detection surfaces.

[0015] In addition, the presence of several detection surfaces arranged at different locations on the probe head according to a complex geometry makes it possible to analyze the fluid in several flow configurations. In particular, having complex shapes and surfaces (including non-planar ones) on the probe head while providing it with several electrodes allows the engineering of flows around the probe head, such that turbulent or laminar flows can for example be caused at different locations around the head and observed specifically by certain electrodes.

[0016] In some examples, each sensing surface includes an arrangement of electrodes directly formed on the surface of the protrusion formed by the probe head.

[0017] Such an arrangement makes it easier to manufacture the head of the analysis device by eliminating the need for a substrate deposited on the protrusion. In particular, it is then possible to avoid a step of positioning and fixing the substrate on the protrusion. This also makes it possible to improve the robustness of the analysis device.

[0018] In some examples, the sensing surfaces are arranged in distinct planes extending along the longitudinal axis of the probe body.

[0019] In some examples, the probe head includes two sensing surfaces that extend in two mutually parallel planes and are arranged back-to-back such that the sensing surfaces face opposite directions.

[0020] According to certain examples, the detection surfaces are arranged relative to each other (in a jointed or non-jointed manner) so as to jointly define a general shape of a prism with a polygonal base whose main axis is collinear with the longitudinal axis of the probe body and each of the faces of which comprises at least one of the detection surfaces.

[0021] In some examples, the sensing surfaces are arranged relative to each other so as to jointly define a general shape of a polygonal-based prism whose major axis is collinear with the longitudinal axis of the probe body; wherein at least one of the sensing surfaces extends over at least two contiguous faces of the prism.

[0022] In some examples, the sensing surfaces include a plurality of pairs of sensing surfaces, each pair of sensing surfaces including two sensing surfaces arranged parallel to each other back to back such that the sensing surfaces face opposite directions, the pairs of sensing surfaces being arranged relative to each other (either contiguous or non-contiguous) so as to jointly define a general shape of a polygonal-based prism whose principal axis is the longitudinal axis of the probe body.

[0023] In some examples, the pairs of detection surfaces form a first set of pairs of detection surfaces and the polygonal-based prism is a first prism; the device further comprising a second set of pairs of detection surfaces similar to the first set; wherein the surface pairs of the second set are arranged relative to each other (in a contiguous or non-contiguous manner) so as to jointly define a general shape of a second polygonal-based prism concentric with the first prism.

[0024] In some examples, the protrusion has a three-dimensional shape including at least one curved face; and the surfaces detection conforms to at least a portion of said at least one curved face.

[0025] In some examples, the protrusion has a general shape of a cylinder whose base is a closed planar curve, the detection surfaces conforming to at least a portion of the external face of the cylinder.

[0026] In some examples, the probe body is comprised of a rear portion and a front portion, the front portion being integral with the probe head and removably cooperating with the rear portion to form a closed assembly configured to isolate the interior of the probe head and the interior of the probe body from the fluid.

[0027] In some examples, the analog interface board is electrically connected to the electrode arrangements via conductive traces disposed on the end of the substrate inserting into the analog interface board.

[0028] In some examples, the analog interface card is configured to produce excitation electrical signals transmitted to the electrode arrangements.

[0029] In some examples, at least one of said excitation electrical signals comprises a continuous signal (DC signal) and / or an oscillating signal (AC signal). The continuous signal and / or the oscillating signal may comprise an electrical voltage or current.

[0030] In some examples, at least one of said excitation electrical signals comprises a square signal alternating between two constant values ​​at a predetermined frequency. In the present description, a square signal may have a duty cycle of any value, in particular a duty cycle value other than 50%.

[0031] In some examples, at least one of said excitation electrical signals comprises a combination of alternating electrical signals at several different frequencies.

[0032] In some examples, at least one of said electrical excitation signals comprises a Dirac pulse.

[0033] In some examples, at least one of said excitation electrical signals comprises several time-multiplexed or frequency-multiplexed electrical signals.

[0034] In some examples, the electrode arrangements include at least one of: a temperature sensor, a water conductivity sensor, a pressure sensor; a fluid flow rate sensor, a sensor for detecting chemical or biological species based on at least one active material coupled to at least one electrode, a sensor sensitive to radio frequency signals or generating radio frequency signals, a sensor sensitive to mechanical vibration signals or generating mechanical vibration signals. In some examples, the conductivity sensor and / or the pressure sensor are based on a capacitive measurement.

[0035] In this description, an active material is defined as a material whose properties are modified by the presence of certain target species (biological or chemical).

[0036] The present disclosure also relates to a system for fluid analysis comprising the analysis device according to the present invention; and - an external signal processing unit, coupled to the electrode arrangements of the probe head via one or more analog interface cards, configured to generate analysis data from electrical signals generated by the one or more analog interface cards.

[0037] In some examples, the system for fluid analysis further includes a communication unit, in communication with the external signal processing unit, being configured to transmit the fluid analysis data to a remote external device.

[0038] In some examples, the communication unit is configured to transmit the fluid analysis data to a remote external device in response to a request from the external device. Brief description of the drawings

[0039] Other characteristics and advantages of the invention will emerge from the following description of embodiments of the invention, given as non-limiting examples, with reference to the appended figures, in which: [Fig 1] Figure 1 is a projection view of several elements of the fluid analysis device according to the present description; [Fig 2] Figure 2 is a perspective view of several elements of the fluid analysis device according to a first exemplary embodiment; [Fig 3] Figure 3 is a perspective view of several elements of the fluid analysis device according to a second exemplary embodiment; [Fig 4] Figure 4 is a perspective view of several elements of the fluid analysis device according to a third exemplary embodiment; [Fig 5] Figure 5 is a perspective view of several elements of the fluid analysis device according to a fourth exemplary embodiment, in a first variant; and [Fig 6] Figure 6 is a perspective view of several elements of the fluid analysis device according to a fourth exemplary embodiment, in a second variant. Detailed description of the invention

[0040] Figure 1 shows a plan projection view of the device for fluid analysis according to the present description. The device is in particular shown in an exploded configuration, that is to say that the elements inside the device are separated from each other.

[0041] The fluid analysis device is formed of a probe body 110 and a probe head 120. When using the device, the probe head 120 is configured to be immersed in a fluid while the probe body 110 is generally kept out of the fluid.

[0042] In the example illustrated in Figure 1, the probe body 110 comprises two removable parts (a front part 110a and a rear part 110b) which are configured to cooperate so as to form, in a closed configuration, a monolithic device capable of being used and in an open configuration, an open device allowing, for example, the replacement of certain elements arranged inside the device. The two parts of the probe body can be joined by different means, for example by fitting together or by screwing.

[0043] The probe body 110 has a generally elongated shape along a longitudinal axis (main axis), which is the vertical axis in Fig. 1, i.e., the axis running from bottom to top of Fig. 1.

[0044] In the examples illustrated in the figures, the elongated shape of the probe body 110 has a cylindrical geometry (cylinder with a circular base) which is advantageous for allowing compatibility with existing interfacing solutions, for example when placing a device in water distribution networks with tubular conduits.

[0045] However, the cylindrical geometry is not essential. In other examples not illustrated in the figures, the probe body may have an elongated shape having a geometry that may be a cylinder with an elliptical base or any other elongated shape compatible with use of the device as a sensor for analyzing a fluid. This is particularly enabled by the use of a device having sensing surfaces that can be arranged to conform to several geometries.

[0046] The probe head 120 forms a protrusion extending from one end of the probe body 110. The protrusion may in particular extend in the direction of the main axis of the probe body or in a different direction, for example a direction inclined at a certain angle relative to the main axis of the probe body.

[0047] In some examples, the protrusion may have a generally cylindrical geometry. For example, a cylindrical shape with the same axis as the probe body. In addition, the protrusion may have an axial section of a similar or different shape than the probe body 120.

[0048] In other examples, the protrusion may adopt any other geometric shape compatible with use in a fluid analysis device, for example the protrusion may have a polyhedron shape, or with flat or curved faces, and concave or convex.

[0049] The protrusion can also take other forms and can therefore be spherical, helical or take any form suitable for being immersed in a fluid.

[0050] The probe head comprises several detection surfaces, only one of which (element 121) is visible in Fig. 1 due to the planar projection. In the example shown in Fig. 1, the surfaces detection surfaces 121 are arranged in distinct planes and extending along the longitudinal axis of the probe body 110. Each detection surface 121 comprises an arrangement of electrodes 123 deposited on a substrate 124. According to certain examples, the substrate 126 extends from an external portion 124 (provided with the electrodes) to an internal portion 1251 inside the probe body 110.

[0051] The electrodes are intended to be in contact with the fluid in order to generate electrical signals representative of parameters of the fluid. For example, the electrodes may be pairs of electrodes covered with a layer of carbon nanotubes functionalized to detect specific chemical species, such as the sensing elements disclosed in [REF 3].

[0052] In some examples, the electrode arrangements 123 may include physical sensors, including: - resistive temperature sensors, in particular composed of a metal coil whose resistance variation depends on the temperature; - water conductivity sensors, formed by a pair of electrodes parallel to each other; - capacitive pressure sensors, for example composed of a stack of two electrodes on either side of a deformable dielectric, piezo-resistive or piezoelectric material. If the material is piezoelectric, the same stack can be used as an ultrasonic transducer to explore the acoustic response of the environment; - flow sensors, for example anemometric sensors, consisting of the combination of a heating wire and a temperature sensor, the water being linked to the electrical capacity between the two electrodes.

[0053] The electrode arrangements 123 may also include chemical sensors, including: - pairs of electrodes, in particular interdigitated ones, on which a sensitive material or a combination of sensitive materials is deposited; - combinations of two or three conductive surfaces of variable shape forming a reference electrode, a working electrode and, optionally, a counter electrode of an electrochemical system. These electrodes may in particular be spherical, rectangular, or polygonal in shape. These electrodes are provided with an active material or a combination of sensitive materials.

[0054] The electrode arrangements 123 may also include sensors such as: - surface acoustic wave sensors (also called surface acoustic wave sensors) “SAW” from the English term “surface acoustic wave”), in which electrode pairs and a sensitive material are combined with a piezoelectric material to generate surface acoustic waves; - radiofrequency or resonant sensors comprising an electrode, covered or not with a sensitive material, the shape of which is optimized to transmit or reflect an electromagnetic wave, particularly in the GHz range.

[0055] The sensitive materials used in the electrode arrangements may include: nanomaterials, including carbon nanotubes, graphene, graphene oxide, 2D thin-film materials (oxidized or non-oxidized), conductive nanoparticles (e.g., gold). The sensitive materials may also include combinations of these materials with functionalizing species to provide selectivity, such as, for example, the species described in patent FR3064999B1, as well as biological species such as RNA, DNA, and aptmers.

[0056] According to some examples, the electrical signals emanating from the electrodes 123 are transmitted from the external part 124 of the substrate (comprising the detection surface 121) to the internal part 125 of the substrate via conductive tracks 127.

[0057] Generally, the fluid analysis device comprises one or more analog interface cards 130 configured to receive the electrical signals from the electrode arrangements 123 and, optionally, transmit them to a processing system external to the device (not shown in the figures).

[0058] The analog interface card 130 may be held within the probe body 110 by a holder. In some examples, the support comprises rails. In this case, the probe body 110 and the analog interface card 130 are sized to maintain a space between the edges of the analog interface card 130 and the probe body 110, so that the analog interface card 130 slides reversibly along the rail to insert into the probe body 110. In some examples, the probe body 110 and the rail are manufactured simultaneously by plastic injection. In other examples, the tubular-shaped rail can be manufactured separately and inserted into the probe body.

[0059] The analog interface card 130 comprises a connector 131 into which a portion of the substrate 126 comprising conductive tracks 127 is inserted in order to allow the electrical connection between the analog interface card 130 and the electrode arrangements 123. In certain examples, such as those illustrated in the figures, the connector is an FFC or FPC type connector allowing the insertion of the end of the substrate 125.

[0060] Figure 2 is a perspective view of elements of a fluid analysis device according to an embodiment in which the probe head 120 comprises two detection surfaces 1211, 1212 arranged back to back on a substantially rectangular protrusion extending from an upper end of the probe body 110.

[0061] The sensing surfaces 1211 and 1212 are similar in structure, i.e., they each comprise an arrangement of electrodes deposited on a substrate. The first sensing surface 1211, which is visible in FIG. 2, comprises an arrangement of electrodes 123 deposited on a substrate 124 which extends inside the probe body 110 in an internal portion 1251 whose end is inserted into an analog interface card 1301. The second sensing surface 1212 (not visible in the figure due to the planar projection view) also comprises an arrangement of electrodes deposited on a substrate which extends inside the probe body in an internal portion 1252 whose end is inserted into the analog interface card 1301.

[0062] In the example shown in Figure 2, the internal parts of the substrates 1251, 1252 are inserted into the same analog interface card 1301. For this purpose, the analog interface card 1301 has a double-sided structure comprising an FPC connector on each of its faces so as to accommodate the two internal substrate parts 1251, 1252. This advantageously makes it possible to avoid the use of two separate analog cards to receive the electrical signals coming from the two detection surfaces and thus to reduce the size within the probe body 110.

[0063] Figure 3 illustrates an exemplary embodiment in which the probe head 120 forms a protrusion extending from the probe body and having the shape of a triangular-based prism whose axis is collinear with the main axis of the probe body. In particular, the triangular base of the prism is an equilateral triangle, however variations of the exemplary fluid analysis device may also have a probe head 120 with a protrusion having the shape of a prism whose base is an isosceles, right-angled, or any other triangle depending on the desired geometry.

[0064] In the exemplary device for fluid analysis illustrated in FIG. 3, the probe head comprises three detection surfaces 1213, 1214, 1215 arranged on the lateral faces of the protrusion. Each detection surface has a structure similar to the detection surfaces previously described. In particular, each of the detection surfaces 1213, 1214, 1215, comprises an arrangement of electrodes deposited on a substrate which extends, respectively, into an internal portion 1253, 1254, 1255.

[0065] In the example illustrated in Figure 3, the internal parts of the substrates 1253, 1254, 1255 are configured to be inserted, by their ends, into three separate analog interface cards 1303, 1304, 1305. Each analog interface card is electrically connected to one of the detection surfaces, and this card is therefore provided with a connector on only one side.

[0066] The example illustrated in Figure 3 comprises three detection surfaces distributed over the faces of a protrusion having three lateral faces, however other exemplary embodiments may comprise more than three detection surfaces distributed over a protrusion comprising a number of faces equal to the number of detection surfaces, each lateral face of the protrusion being covered with a detection surface.

[0067] This type of arrangement may in particular comprise a protrusion having the shape of a cylinder with a polygonal base whose axis is collinear with the axis of the probe body. In this case, each lateral face of the protrusion may accommodate a detection surface comprising an arrangement of electrodes deposited on a substrate. In addition, the substrate of each face may extend into an internal part inserted into a separate analog card.

[0068] In addition, it is also possible to have a number of analog interface cards less than the number of detection surfaces. For this, in a variant (not illustrated in the figures), the substrates corresponding to detection surfaces arranged on opposite faces of the protrusion can be inserted, by their ends, on either side of the same double-sided analog interface card comprising a connector on each face.

[0069] In another variant (not illustrated in the figures), the substrates corresponding to detection surfaces arranged on contiguous faces of the protrusion can be inserted into two connectors juxtaposed on one face of a single-sided analog interface board. This is made possible in particular by the use of a flexible substrate allowing a certain degree of twisting so that the internal parts of the substrates from contiguous detection surfaces can be brought into the same plane so as to be inserted into two connectors juxtaposed on the same analog interface board. This is particularly advantageous in the case of a protrusion having contiguous side surfaces forming an angle greater than 90°.

[0070] Furthermore, in other examples (not shown in the figures) it is possible for the detection surfaces to cover two contiguous lateral faces of the protrusion. Such detection surfaces then conform to the succession of the two faces by curving. This can be advantageously enabled by the use of a flexible substrate on which the electrode arrangements are printed.

[0071] Figure 4 illustrates an exemplary embodiment in which the probe head 120 comprises three pairs of detection surfaces 1201, 1202, 1203 arranged relative to each other in a non-contiguous manner so as to jointly define a general shape of a prism with a triangular base whose main axis is the longitudinal axis of the probe body. The sensing surfaces extend in the direction of the probe body axis in separate planes.

[0072] Each pair of detection surfaces (e.g., element 1201) comprises two detection surfaces (e.g., elements 1201b, 1201b) arranged back-to-back on two opposite faces of a blade-shaped protrusion. In Figure 4, due to the perspective view, only one detection surface is visible for each pair of detection surfaces 1201, 1202, 1203. However, the device according to this example comprises six detection surfaces.

[0073] The six detection surfaces corresponding to the three pairs of detection surfaces 1201, 1202, 1203 are similar to the detection surfaces previously described. Each detection surface therefore comprises an arrangement of electrodes deposited on a substrate which extends towards the inside of the probe body in an internal part. Thus the first pair of detection surfaces 1201 consists of two detection surfaces 1201a, 1201b each comprising an arrangement of electrodes deposited on a substrate which extends towards the inside of the probe body 110 in an internal part, so that two internal substrate parts 1261a, 1261b corresponding respectively to the two detection surfaces 1201a, 1201b extend inside the probe body so as to be inserted into two connectors of an analog interface card.Similarly, the second pair 1262 and the third pair 1263 include electrode arrangements deposited on a substrate that extends inwardly of the probe body 110 at internal portions (1262a, 1262b; 1263a, 1263b) configured to fit into the analog interface card connectors (1302, 1303), respectively.

[0074] Figures 5 and 6 illustrate two variations of an exemplary probe head 120 having a protrusion 126 with a cylindrical geometry. In these examples, the sensing surface 1219 is made from a flexible substrate that conforms to a portion of the side surface of the cylindrical protrusion 126.

[0075] In the variant of Figure 5, the protrusion 126 is exposed, so that the entire lateral surface of the protrusion can come into contact with a fluid. It is possible to ensure that the entire of the lateral surface of the protrusion 126 is provided with a detection surface 1219 comprising electrodes.

[0076] In the variant of Figure 6, the protrusion is only exposed on one half of the circumference, the other half being covered by an extension 128 of the front part of the probe body 110a. This extension 128 of the front part of the probe body 110a forms a half-collar which isolates from the fluid a part of the lateral surface of the protrusion 126. Such a solution is notably useful for rapid assembly of the system and for reducing the manufacturing costs of the probe head. For example, the protrusion can be a separate cylinder on which the detection surface is fixed. The device is then assembled by inserting the cylinder into an orifice of the probe body, the collar serving as an insertion guide. Such a geometry is useful because cylindrical structures are more easily machinable. In addition, the half-collar 128 can serve as electromagnetic protection for the detection surfaces.

[0077] The interfacing circuit allows multiple sensing surfaces to be connected to a single analog interface board. In particular, the role of the interfacing circuit is to group the connections of the sensing surfaces that are in separate planes and to interface them in a single plane, the plane of the analog interface board. This allows for cost reduction and greater ease of probe assembly.

[0078] The interfacing circuit is thus not limited to a planar geometry, in particular, the interfacing circuit can adopt complex three-dimensional shapes in order to adapt to the geometry of the probe head used in the analysis device.

[0079] In some examples, the interfacing circuit may contain at least one interface module, each interface module providing electrical connection to at least one sensing surface, and a routing module enabling successive interrogation of each sensing surface. The interface module contains at least one connector and a sufficient number of multiplexers to connect all the electrodes of the sensing surface. The routing module contains a multiplexer that allows all the interface modules to be connected, a microcontroller enabling control of all the multiplexers. of the interface circuit, and a connector for connecting the interface circuit to the analog interface card.

[0080] The size and / or complexity of the analog interface card can be increased according to the requirements of the device. For example, in the case of an analog card connected to several detection surfaces, it is possible to increase the number of microprocessors included in the analog interface card in order to process in parallel the signals coming from the different detection surfaces, the electronic processing circuits associated with the microprocessor can then also be multiplied.

[0081] In some examples, each microprocessor communicates with an external processing unit via, for example, an I2C (Inter-Integrated Circuit) computer bus. This is particularly advantageous in the case of communication with an arbitrary number of devices.

[0082] When the number of electrodes and sensing surfaces reaches significant values ​​for the device, it may be advisable to increase the number of analog interface cards in the probe tube. This may also be advantageous in the case of a probe head with a certain complex geometry requiring several analog interface cards. In particular, in the case of a polygonal probe head, it may be difficult to connect several sensing surfaces to the same analog interface card without imposing too much stress on the substrate, even if the latter is flexible. Thus, the tube may comprise a support allowing the maintenance of a plurality of analog interface cards within the probe body.

[0083] In some examples, the analog interface card includes shielding to prevent electromagnetic interference with other electronic systems. In particular, in the case of a device comprising several analog interface cards, the shielding of the analog interface cards makes it possible to prevent mutual interference between these cards.

[0084] The probe body and probe head may be shielded internally (e.g., by including a thin metal layer on the opposite side of the sensing surface or on the inside of the probe body) or externally (e.g., by placing the probe body containing the interface circuit board in a grounded metal case). The probe body and probe head may also be partially or completely metallic. In the case of a metallic probe head, each detection surface may, if necessary, be electrically isolated from the probe head by an insulating layer.

[0085] Shielding of the probe head 120 and / or the probe body 110 may be useful independently of the presence of shielding of the analog interface card 130. Indeed, shielding of the connections between the electrodes of the probe head and the analog interface card improves the performance and robustness of the device because these connections can be subject to electromagnetic noise.

[0086] Generally, the analog interface board is configured to receive electrical signals from the electrode arrangements to which the analog interface board is connected. The electrical signals transmitted from the electrodes to the analog interface board are potential differences or electrical currents.

[0087] Furthermore, the acquisition of electrical data may consist of the acquisition of a complete signal from the electrodes or simply of the acquisition of a portion of this signal, for example in order to save energy and / or computing power for the microprocessor processing the signals.

[0088] In some examples, the analog interface card generates electrical excitation signals that are transmitted to the electrode arrangements. The electrodes are generally excited successively for a duration ranging from 100ms to 10s. The voltage of the electrical excitation signal should preferably not exceed 1.2V to avoid electrolysis of the water which can disturb the measurements.

[0089] In a variant, some of the electrodes are excited by an alternating current (AC) electrical signal, for example an electrical signal with a frequency greater than 100 Hz. The frequency can be different between the different types of electrodes. This makes it possible to capture phenomena with dynamics associated with different time scales and to overcome electromagnetic noise due to the environment.

[0090] In a second variant, an electrode can be excited successively with electrical signals of different frequencies, thus allowing, for example, to obtain an impedance spectroscopy of the excited electrode.

[0091] In a third variant, the electrodes are excited by a square signal (also called a square wave), that is, a signal consisting of an alternation between constant voltage or current values ​​of different levels (also called alternating DC in the present description). The low level of the square signal may be equal to 0V or to a negative value opposite (or not) to the high level of the square signal. The frequency of the square signal is from 0.1 to 10 kHz, and the duty cycle is for example equal to 50%. In other variants, the square signal may alternate between more than two levels.

[0092] Using a square wave signal (with two or more levels) is particularly advantageous because it allows one to approximate an oscillating signal such as a sinusoidal signal (AC signal) while being easy to generate and acquire without requiring a complex electronic architecture. It is possible to use a symmetrical alternating DC signal, i.e. a signal for which the minimum value is the opposite of the maximum value. It is also possible to use a positive signal, which further simplifies the required electronic architecture.

[0093] In some examples, the duty cycle is 5% or less, simulating a Dirac pulse. In some examples, the signal is a single Dirac pulse, that is, a constant signal with a duration between 10 ms and 100 ms.

[0094] In the case of excitation by an alternating signal (such as an AC signal or a square signal), the acquisition of the data transmitted by the electrodes may consist of the successive acquisition of two measurement points per period of the alternating signal. Preferably, this may consist of the acquisition of 5 measurement points or even 100 measurement points per period of the alternating signal.

[0095] The acquired data can be processed by Fourier transform or wavelet transform of the data. Alternatively or successively, the data acquisition can be followed by a calculation of the maximum or an average on the acquired data.

[0096] In addition, the acquisition can be followed by signal processing such as averaging of the data over several excitations, in particular quadratic averaging. Signal processing can also understand the detection of a phase shift or the detection of a maximum.

[0097] In the case of a square excitation signal, signal acquisition can be time-limited to the end of each level, or to the end of a single level of the square signal.

[0098] In the case of excitation by a signal comprising a Dirac pulse, the data acquisition may consist of the acquisition of at least 5 points during the Dirac pulse, preferably 10 to 20 points. In addition, this may include a succession of acquisitions of measurement points during the Dirac pulse and after the Dirac pulse, over a total duration which may be equal to 5 times or even 10 times the duration of the Dirac pulse.

[0099] In some examples, the excitation signal, such as AC or square wave, may be time or frequency multiplexed to maximize the number of sensors that can be read at the same time.

[0100] This configuration is particularly advantageous because, in the case of a large number of electrodes to be interrogated, the successive interrogation of the electrodes could lead to a total interrogation time of all the sensors which becomes too long compared to the constraints of the application, which is resolved by the use of multiplexing of the excitation signals.

[0101] Although the present disclosure has been described with reference to a specific exemplary embodiment, it is obvious that various modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. Furthermore, individual features of the various embodiments recited may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

CLAIMS 1. Device for analyzing a fluid, comprising: - a probe body (110) of generally elongated shape along a longitudinal axis, the probe body being configured to be impermeable to the fluid; - a probe head (120) forming a protrusion extending from one end of the probe body (110) and having a plurality of sensing surfaces (121), wherein each sensing surface comprises an arrangement of electrodes (123) configured to be sensitive to parameters of the fluid upon contact with the fluid; and - an analog interface card (130) arranged inside the probe body (110), electrically connected to the electrode arrangements (123) of all the detection surfaces (121), and configured to exchange electrical signals with the electrode arrangements; wherein the electrode arrangement (123) of each detection surface (121) is deposited on a substrate, said substrate (124) being fixed on the protrusion formed by the probe head; wherein the analog interface card (130) is unique and is electrically connected to all the electrode arrangements (123) via an interfacing circuit into which ends of all the substrates are inserted.

2. Device according to claim 1, in which the detection surfaces (1211, 1212) are arranged in separate planes extending along the longitudinal axis of the probe body.

3. Device according to any one of claims 1 to 2, wherein the probe head (110) comprises two detection surfaces (1211, 1212) which extend in two planes parallel to each other and which are arranged back to back so that the detection surfaces face opposite directions.

4. Device according to any one of claims 1 to 2, in which the detection surfaces (1213, 1214, 1215) are arranged relative to each other so as to jointly define a shape general of a prism with a polygonal base whose main axis is collinear with the longitudinal axis of the probe body and each of whose faces comprises at least one of the detection surfaces (1213, 1214, 1215).

5. Device according to any one of claims 1 to 2, in which the detection surfaces (1213, 1214, 1215) are arranged relative to each other so as to jointly define a general shape of a prism with a polygonal base whose main axis is collinear with the longitudinal axis of the probe body; in which at least one of the detection surfaces (1213, 1214, 1215) extends over at least two contiguous faces of the prism.

6. Device according to any one of claims 1 to 2, wherein the detection surfaces comprise several pairs of detection surfaces (1201, 1202, 1203), each pair (1201) of detection surfaces comprising two detection surfaces (1201a, 1201b) arranged parallel back to back so that the detection surfaces face opposite directions, the pairs of detection surfaces being arranged relative to each other so as to jointly define a general shape of a prism with a polygonal base whose main axis is the longitudinal axis of the probe body.

7. A device according to claim 6, wherein the pairs of detection surfaces form a first set of pairs of detection surfaces and the polygonal-based prism is a first prism; the device further comprising a second set of pairs of detection surfaces similar to the first set; wherein the surface pairs of the second set are arranged relative to each other so as to jointly define a general shape of a second polygonal-based prism concentric with the first prism.

8. The device of claim 1, wherein the protrusion (126) has a three-dimensional shape comprising at least one curved face; and the sensing surfaces (1219) conform to at least a portion of said at least one curved face.

9. Device according to claim 8, in which the protrusion (1219) has a general shape of a cylinder whose base is a closed plane curve, the detection surfaces conforming to at least a part of the external face of the cylinder.

10. Device according to any one of the preceding claims, wherein the probe body (110) is composed of a front part (110a) and a rear part (110b), the front part (110a) being integral with the probe head (120) and cooperating removably with the rear part (110b) to form a closed assembly configured to isolate the interior of the probe head and the interior of the probe body from the fluid.

11. A device according to any preceding claim, wherein the analog interface card is electrically connected to the electrode arrangements (123) via conductive tracks arranged on the end of the substrate fitting into the analog interface card.

12. Device according to any one of the preceding claims, in which the analog interface card is configured to produce electrical excitation signals transmitted to the electrode arrangements (123).

13. Device according to claim 12, wherein at least one of said electrical excitation signals comprises a continuous signal and / or an oscillating signal.

14. Device according to claim 12, wherein at least one of said electrical excitation signals comprises a square signal alternating between two constant values ​​at a predetermined frequency.

15. Device according to claim 12, wherein at least one of said electrical excitation signals comprises a combination of alternating electrical signals at several different frequencies.

16. A device according to claim 12, wherein at least one of said electrical excitation signals comprises a Dirac pulse.

17. Device according to claim 12, wherein at least one of said electrical excitation signals comprises several electrical signals multiplexed in time or multiplexed in frequency.

18. Device according to any one of the preceding claims, wherein the electrode arrangements (123) comprise at least one of: a temperature sensor, a water conductivity sensor, a pressure sensor; a fluid flow rate sensor, a sensor for detecting chemical or biological species based on at least one active material coupled to at least one electrode, a sensor sensitive to radiofrequency signals or generating radiofrequency signals, a sensor sensitive to mechanical vibration signals or generating mechanical vibration signals.

19. System for fluid analysis comprising: - the analysis device according to any one of the preceding claims; and - an external signal processing unit, coupled to the electrode arrangements (123) of the probe head (120) via one or more analog interface cards (130), configured to generate analysis data from electrical signals generated by the one or more analog interface cards (130).

20. The system of claim 19, further comprising: - a communication unit, in communication with the external signal processing unit, and configured to transmit the fluid analysis data to a remote external device.

21. The system of claim 20, wherein the communication unit is configured to transmit the fluid analysis data to a remote external device in response to a request from the external device.

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