LIQUID METERS WITH ALTERNATE POWER SUPPLY

Description

Technical field

[0001] The invention belongs to the technical field of fluid meters. A fluid meter is a metrology device configured to perform metrological measurements in a fluid circulation pipeline. The fluid may be liquid, such as water or oil, or gaseous, such as a gaseous mixture of hydrocarbons consisting primarily of methane such as natural gas. The metrological measurements are generally a volume or flow rate relative to the fluid circulating in the pipeline. Technological background

[0002] In order to know certain metrological data concerning the circulation of a fluid in a pipeline, a fluid meter is usually used to generate and make available metrological measurements. In order to record these metrological measurements, fluid meters equipped with means of communicating information relating to said metrological data have been developed. These means of communication can be adapted for remote communication, and for example allow wired or wireless transmission of this information. The means of communication can also present several pieces of information in a display, organized according to menus. In all cases, these metrological meters require a power supply.However, the meters may be located in locations that do not allow easy connection to the electricity network, so they must have an independent power supply, not connected to the electricity network.

[0003] The simplest way to independently power a fluid meter is to equip it with an electric battery, i.e. an energy storage element that cannot be recharged on-site. However, the energy storage capacity must be sufficient to provide a power supply for a long period (typically 20 years), which means using very large batteries. In addition, the battery life depends on the meter's power consumption, which can significantly reduce the battery life, which in any case eventually runs out and must be changed, a tedious operation requiring monitoring of the battery's condition.

[0004] In order to overcome these drawbacks, it has been proposed to replace the electric battery with a rechargeable battery, for example powered by an electric generator configured to be driven by the circulation of the fluid in the pipe and generate electricity to recharge the battery.

[0005] However, the potentially intermittent nature of fluid circulation requires a battery with a large electrical storage capacity, which results in high bulk and costs. In addition, the irregularity of fluid circulation episodes can increase the number of incomplete charge-discharge cycles of the battery, reducing its performance over time.

[0006] Patent application WO2015150247 describes a method for operating an electronic device carried by an apparatus and apparatus provided with a turbine capable of being driven in rotation by a flow of a fluid and a means for detecting at least one determined angular position of said turbine, delivering an electrical pulse each time the turbine passes through this angular position. A pulse counter can count the delivered pulses. An electric current generator can power the electronic device. An electrical energy accumulator can be charged by the current generator and power the electronic device. However, this electric energy accumulator only operates when its charge remains sufficient. In order to have a power supply during the shutdown of the turbine, the accumulator can be replaced by a battery, the size of which must be all the larger as the shutdown periods are frequent or prolonged. Presentation of the invention

[0007] The invention therefore aims to propose a fluid meter equipped with an electrical power supply with a long service life, less bulky and more reliable.

[0008] To this end, the invention proposes a fluid meter configured to carry out metrological measurements in a fluid circulation pipe and to communicate information relating to said metrological data, comprising: an electrical generator configured to be driven by the circulation of the fluid in the fluid pipe and generate electricity, at least one metrological sensor configured to perform metrological measurements in the fluid pipe, a control unit configured to receive the metrological measurements and to communicate information relating to said metrological data, a power supply unit coupled to the electrical generator, and configured to supply energy to the control unit, wherein the power supply unit comprises a first power supply path comprising at least one battery, and a second power supply path connected to the electrical generator, the second power supply path comprising a capacitor and a first switch configured to selectively couple the capacitor and the electrical generator,the power supply further comprising a second switch configured to selectively couple the first power supply path or the second power supply path to the control block, , the power supply further comprising a current sensor configured to determine a current measurement representative of an intensity of a charging or discharging current of the capacitor, the first switch and the second switch being configured to be controlled by the control unit according to a state of charge of the capacitor determined by the control unit from the current measurement.

[0009] By alternately supplying power from the first power supply path and the second power supply path, it is possible to continuously supply electricity to the control unit while only requiring a battery with low storage capacity, less bulky, less expensive, and with an extended service life.

[0010] Preferably, in order to favor the power supply by the capacitor, the control block is configured to, at least when the electric generator generates electricity,: a) open the first switch and position the second switch on the second power supply path when the state of charge becomes greater than a high threshold, and b) close the first switch and position the second switch on the first power supply path when the state of charge of the capacitor becomes lower than a low threshold.

[0011] The invention is advantageously supplemented by the following various characteristics taken alone or according to their various possible combinations: the high threshold is greater than or equal to 80% of a maximum state of charge, and the low threshold is less than or equal to 10% of a maximum state of charge; the control block is configured to update a previous state of charge with a multiple of a square of the current intensity at each time step; the control block is configured to update at each time step a previous state of charge with a product of the current intensity and the voltage between a first terminal of the capacitor between the first switch and the second switch and the reference potential, said voltage decremented by the voltage across the resistor by the current intensity; the state of charge is expressed as a proportion of a maximum energy reserve of the capacitor; the meter comprises a resistor in series between the capacitor and a reference voltage, and the current measurement is determined from a voltage across the resistor;the capacitor has a terminal coupled to a terminal of the first switch and to a terminal of the second switch; the communication of the information relating to the metrological data is carried out by display on a screen and / or by transmission of said metrological data; the first power supply path and the second power supply path are independent; the battery is an electrical energy storage element which cannot be recharged, or whose configuration in the power supply unit makes it impossible to charge within this power supply unit.; Presentation of figures

[0012] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which: there figure 1 is a schematic overview of a fluid meter according to a possible embodiment of the invention; the figure 2is an implementation diagram of a fluid meter according to a possible embodiment of the invention. Detailed description

[0013] There figure 1shows a fluid meter configured to perform metrological measurements in a fluid circulation pipe 2 and to communicate information relating to said metrological data. Typically, the fluid circulation pipe 2 is part of the fluid meter in the sense that the fluid meter comprises a portion of pipe in which the fluid circulates, which is integrated into the fluid circulation network. To perform metrological measurements, the fluid meter comprises at least one metrological sensor 4 configured to perform metrological measurements in the fluid pipe 2. The metrological sensor 4 is preferably arranged in the fluid pipe 2. The type of metrological sensor 4 depends on the technology used to perform the measurements, which may be ultrasonic, electromagnetic, thermal or Coriolis technology.In the example illustrated, two ultrasonic transducers are arranged opposite each other in the pipeline in order to carry out metrological measurements by ultrasound, in a known manner. The metrological measurements are generally a volume or a flow rate relative to the fluid circulating in the pipeline 2, derived from the data collected by the metrological sensor(s) 4.

[0014] The fluid meter comprises a control unit 6 comprising at least one processor and a memory, and which is configured to receive the metrological measurements from the metrological sensor 4, and to communicate the information relating to said metrological data. Typically, the metrological sensor 4 can be connected to the control unit 6, for example by a wired connection, and transmits the metrological measurements to the control unit 6.

[0015] The communication of the information relating to the metrological data is carried out by display on a screen and / or by transmission. The fluid meter may have a display screen 7 where the information relating to the metrological data can be displayed. The fluid meter may be provided with a human-machine interface such as a button making it possible to cause the display of this information relating to the metrological data, and possibly to vary this display, for example by making it possible to scroll through different types on the display screen 7. The information relating to the metrological data may be transmitted outside the fluid meter, preferably by a wireless link, in which case the fluid meter may comprise an antenna and any other known element making it possible to establish remote communication with the fluid meter.

[0016] Preferably, the fluid meter complies with the European Union Directive 2014 / 32 / EU on measuring instruments, better known by its acronym MID for "Measuring Instruments Directive". In particular, the fluid meter must be able to communicate information relating to metrological data at all times. Similarly, the fluid meter must be able to carry out metrological measurements at all times. Therefore, the fluid meter must have a permanent power supply.

[0017] For this purpose, the fluid meter comprises a power supply unit 10 configured to permanently supply electricity to the control unit 6, and an electric generator 12 configured to be driven by the circulation of the fluid in the pipe and generate electricity, the power supply unit 10 being coupled to the electric generator 12.

[0018] At least part of the electrical generator 12 is arranged in the pipe 2 in contact with the fluid in order to extract mechanical energy and convert it into electricity. Typically, this electrical generator 12 is a turbine, preferably with blades, integrating a rotor and a stator. The electrical generator 12 provides electricity available outside the pipe. Preferably, the electrical generator 12 is arranged downstream, in the direction of circulation of the fluid, relative to the metrological sensor 4 in the fluid pipe, so as not to disturb these metrological measurements.

[0019] The power supply unit 10 comprises two separate and independent channels: a first power supply channel 14 comprising at least one battery 16 and a second power supply channel 20 connected to the electrical generator 12. A battery (or "primary cell" in English) is understood to mean an electrical energy storage element which cannot be recharged, or whose configuration in the power supply unit 10 makes charging within this power supply unit 10 impossible. Typically, the first power supply channel 14 comprises only the battery 16. The battery 16 preferably has a maximum energy reserve of less than 100 Wh, such as for example 30.6 Wh (8.5 Ah on 3.6 V) or 68.4 Wh (19 Ah on 3.6 V).

[0020] The second power supply path 20 comprises a capacitor C1 and a first switch S1 configured to selectively couple or decouple the capacitor C1 and the electrical generator 12. The capacitor C1 preferably has a maximum energy reserve E max greater than or equal to 0.5 Wh, and more preferably greater than or equal to 0.8 Wh. For example, the capacitor C1 can deliver an electrical charge of 0.222 Ah at 3.6 V. The capacitor C1 is preferably a supercapacitor. Typically, the capacitor C1 can be a hybrid layer supercapacitor, or HLC for the English “Hybrid Layer Capacitor”, but can also be any type of supercapacitor making it possible to offer a maximum energy reserve E max greater than or equal to 0.5 Wh. Preferably, the maximum energy E max of the capacitor C1 is at least 20 times lower than the maximum energy of the battery 16.

[0021] The first switch S1 is arranged between the capacitor C1 and the electric generator 12. The first switch S1 is controlled by the control block 6 for its opening and closing. The first switch S1 is preferably a relay, for example an electromechanical relay.

[0022] The second power supply path 20 may comprise, in series between the electric generator 12 and the first switch S1, different current shaping elements, and for example a rectifier 22 in series with a voltage regulator 24. The power supply unit 10 further comprises a current sensor 26 configured to determine a current measurement representative of an intensity of the charging or discharging current of the capacitor C1. In the illustrated example, a first terminal of the capacitor C1 is connected between the first switch S1 and the second switch S2 (at this connection point, it is considered that the voltage V between said connection point and the reference potential to which the resistor R1 is connected is known by design), and a second terminal of the capacitor C1 is connected in series with a terminal of the resistor R1, which is connected to a reference potential (e.g. ground) by its other terminal.A measurement relating to the current flowing through the resistor R1 is recorded by the current sensor 26, typically a voltage V r across the resistor R1 from which a signed current measurement I (positive during charging and negative during discharging) can be derived as soon as the resistance value of the resistor R1 is known. Thus, the current sensor 26 can be a voltmeter. The resistance value of the resistor R1 can be low, and is for example less than 800 mΩ.

[0023] The current sensor 26 transmits its measurement to the control block 6. Preferably, the current measurement is an average of the intensity values ​​recorded over a period of time, typically over a time step.

[0024] The power supply 10 further comprises a second switch S2 configured to selectively couple the first power supply channel 14 or the second power supply channel 20 to the control block 6, thereby selecting whether the control block 6 is electrically powered by the first power supply channel 14 or the second power supply channel 20.

[0025] The first switch S1 and the second switch S2 are controlled by the control block 6 for their state: open or closed for the first switch S1, selection of the power supply path for the second switch S2. When the first switch S1 is closed and the second switch S2 connects the control block 6 to the battery 16, which then powers the control block 6, the capacitor C1 is coupled to the electric generator 12 and recharges, storing electrical energy. When the first switch S1 is open and the second switch S2 connects the control block 6 to the capacitor C1 of the second power supply path 20, the control block 6 is powered by the capacitor C1, the battery 16 not being used.

[0026] The first switch S1 and the second switch S2 are configured to be controlled by the control block 6 according to a state of charge of the capacitor C1 determined by the control block 6 from the current measurement. The control block 6 is in fact configured to determine a state of charge (SoC) of the capacitor C1 from the current measurement. More precisely, the state of charge is updated at each time step thanks to the current measurement. For example, when charging the capacitor C1, the state of charge (SoC) at the previous instant is incremented by a multiple of the square of the current intensity, more precisely by the product of the current intensity I and the voltage V decremented by the voltage across the resistor R1 by the current intensity.

[0027] Preferably, the state of charge is expressed as a proportion of a maximum energy reserve E max of the capacitor C1. It follows that the expression for energy, i.e. (VR 1 .I).I, is divided by E max , with R1 the resistance value of resistor R1, and therefore that SoC(t+T)= SoC(t)+T.((VR 1 .I).I / E max . When capacitor C1 discharges, the state of charge (SoC) at the previous instant is decremented by a multiple of the square of the current, i.e. incremented by the product of the current intensity and the voltage V decremented by the voltage across resistor R1 (which is negative in this case) by the current intensity (also negative), hence SoC(t+T)= SoC(t)+T.(VR 1 .I).I / E max . Preferably, the time step T is less than 10 seconds. The time step T is preferably greater than 0.1 seconds. For reasons of simplicity, the step time here is 1 second, which simplifies the determination of the state of charge: in charge: SoC(t+T)= SoC(t)+(VR 1 .I).I / E max, in discharge: SoC(t+T)= SoC(t)+(VR 1 .I).I / E max.

[0028] If the state of charge is sufficiently high, the second switch S2 connects the second power supply channel 20 to enable the power supply of the control unit 6 by the capacitor C1 of the second power supply channel 20. Otherwise, the second switch S2 connects the first power supply channel 14 to enable the recharging of the capacitor C1 while it is the battery 16 of the first power supply channel 14 which powers the control unit 6. The control unit 6 is configured to, at least when the electric generator 12 generates electricity: opening the first switch S1 and positioning the second switch S2 on the second power supply channel 20 when the state of charge becomes greater than a high threshold, closing the first switch S1 and positioning the second switch S2 on the first power supply channel 14 when the state of charge of the capacitor C1 becomes lower than a low threshold.

[0029] Estimating the state of charge from the current measurement is more accurate than other approaches, for example based on the voltage across capacitor C1, and therefore makes it possible to make the most of the storage capacities of capacitor C1.

[0030] There figure 2shows an example of an operating diagram of the fluid meter showing the variations of the states of the first switch S1 and the second switch S2, with different steps implemented by the control block 6. In a default state (S00), for example before the fluid meter is set up, the second switch S2 is on battery 16, i.e. connects the control block 6 to the first power supply channel 14. The first switch S1 is preferably closed. The charge of the capacitor C1 may be zero or very low. The default state may for example be maintained until a non-zero charging current is detected by the current sensor 26.

[0031] In a first step (S01), the first switch S1 is closed, connecting the capacitor C1 to the electricity generator. The second switch S2 is on battery 16. The capacitor C1 can then charge with electrical energy. In a second step (S02), the charging current is measured via the current sensor 26, and the state of charge is updated according to the measurement of the charging current. More precisely, as explained above, the state of charge is incremented by a multiple of the square of the intensity of the charging current. Then, a test (S03) is carried out to check whether the state of charge is greater than a high threshold, by means of a comparison between the current state of charge and this high threshold. The high threshold is used to check that the capacitor C1 is sufficiently charged, and therefore corresponds to a state of charge close to the maximum energy E max that the capacitor can store.Typically, the upper threshold is at least 80% of the maximum energy E max , and preferably at least 90% of the maximum energy E max .

[0032] If this is not the case, the control block 6 returns to the second step (S02) to continue charging the capacitor C1. If the state of charge is greater than the high threshold, then the control block 6 commands the opening of the first switch S1 and the passage of the second switch S2 on the capacitor C1, thus coupling the control block 6 and the second power supply channel 20. The control block 6 is now powered by the capacitor C1 which is discharging, and no longer by the battery 16. The opening of the first switch S1 makes it possible to decouple the capacitor C1 and the electrical generator 12, thus avoiding possible electrical disturbances. During the discharge of the capacitor C1, at each time step a step (S05) of measuring the discharge current and an update of the state of charge is carried out. More precisely, as explained above, the state of charge is decremented by a multiple of the square of the intensity of the discharge current.Then, a test (S06) is performed to check whether the state of charge is below a low threshold, by means of a comparison between the current state of charge and this low threshold. The low threshold is used to check that the capacitor C1 has been sufficiently discharged, and therefore corresponds to a state of charge close to the minimum. Typically, the low threshold is less than 10% of the maximum energy E max , and is for example less than or equal to 5% of E max .

[0033] If the state of charge is greater than the low threshold, the discharge of the capacitor C1 continues and a new step (S05) of measuring the discharge current and updating the state of charge is carried out. If the state of charge is less than or equal to the low threshold, this means that the capacitor C1 has been sufficiently discharged, and that it must now be recharged. Consequently, the control block 6 then returns to step (S01), closes the first switch S1 and switches the second switch S2 to the first power supply path 14, on the battery 16.

[0034] As can be seen in this method, the control unit 6 is configured to maximize the use of the capacitor C1 and save the battery 16. The battery 16 is then only used to allow the capacitor C1 to be recharged. Thanks to the permanence of the power supply, the fluid meter is capable of communicating information relating to the metrological data, for example by displaying them, even in the absence of fluid circulation. It should be noted that the charging time of the capacitor C1 is inversely proportional to the rotational speed of the turbine. It is easy to ensure, given the low energy requirements of the control unit 6, that the recharge time of the capacitor C1 is much shorter than the discharge time of the capacitor C1. The capacitor C1 can provide a significant portion of the power supply to the control unit 6.The less stressed 16 battery can be chosen with a lower energy storage capacity, therefore with reduced size and lower cost, while preserving or increasing its lifespan.

[0035] The invention is not limited to the embodiment described and shown in the attached figures. Modifications remain possible, in particular from the point of view of the constitution of the various technical characteristics or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

1. A fluid meter configured to perform metrological measurements in a fluid circulation pipe and to communicate information relating to said metrological data, comprising: - an electrical generator (12) configured to be driven by the circulation of the fluid in the fluid pipe (2) and to generate electricity, - at least one metrological sensor (4) configured to perform metrological measurements in the fluid pipe (2), - a control block (6) configured to receive the metrological measurements and to communicate information relating to said metrological data, - a power supply block (10) coupled to the electrical generator (12), and configured to supply energy to the control block (6), wherein the power supply block (10) comprises a first supply path (14) comprising at least one primary cell (16), and a second supply path (20) connected to the electrical generator (12), the second supply path (20) comprising a capacitor (C1) and a first switch (S1) configured to selectively couple the capacitor (C1) and the electrical generator (12), the power supply block (10) further comprising a second switch (S2) configured to selectively couple the first supply path (14) or the second supply path (20) to the control block (6), the power supply block (10) further comprising a current sensor (26) configured to determine a current measurement representative of a intensity of a charge or discharge current of the capacitor (C1), the first switch (S1) and the second switch (S2) being configured to be monitored by the control block (6) as a function of a state of charge of the capacitor (C1) determined by the control block (6) from the current measurement.

2. A fluid meter according to claim 1, wherein the control block (6) is configured to, at least when the electrical generator (12) generates electricity, : - open the first switch (S1) and position the second switch (S2) on the second supply path (20) when the state of charge becomes greater than a high threshold, - close the first switch (S1) and position the second switch (S2) on the first supply path (14) when the state of charge of the capacitor (C1) becomes smaller than a low threshold.

3. The fluid meter of claim 2, wherein the high threshold is greater than or equal to 80% of a maximum state of charge, and the low threshold is less than or equal to 10% of a maximum state of charge.

4. A fluid meter according to any one of the preceding claims, wherein the control block (6) is configured to update a previous state of charge with a multiple of a square of the intensity of the current at each time step.

5. A fluid meter according to any one of the preceding claims, wherein the state of charge is expressed as a proportion of a maximum energy reserve of the capacitor (C1).

6. A fluid meter according to any one of the preceding claims, comprising a resistor (R1) in series between the capacitor (C1) and a reference voltage, and the measurement of the current is determined from a voltage across the resistor (R1).

7. A fluid meter according to claim 6, wherein the control block (6) is configured to update at each time step a previous state of charge with a product of the intensity of the current and the voltage (V) between a first terminal of the capacitor (C1) between the first switch (S1) and the second switch (S2) and the reference potential, said voltage being decremented from the voltage across the resistor (R1) by the intensity of the current.

8. A fluid meter according to any one of the preceding claims, wherein the capacitor (C1) has a terminal coupled to a terminal of the first switch (S1) and to a terminal of the second switch (S2).

9. Fluid meter according to any one of the preceding claims, in which the communication of information relating to the metrological data is performed by display on a screen and / or by transmission of said metrological data.

10. A fluid meter according to any one of the preceding claims, wherein the first supply path (14) and the second supply path (20) are independent.

11. A fluid meter according to any one of the preceding claims, wherein the primary cell (16) is an electrical energy storage element that cannot be recharged, or whose configuration in the power supply block (10) makes it impossible to charge within this power supply blocks (10).