Ultrasonic fluid gauge including pressure sensor

Abstract

An ultrasonic fluid gauge (1) includes: an ultrasonic measuring device (6); a valve (12) including a movable member (14); a position sensor (15) configured to measure the current position of the movable member; a pressure sensor (16) arranged to measure the pressure of a fluid in a pipe; and a processing unit (5) arranged to evaluate the current flow rate based on the current position of the movable member, the pressure of the fluid at the current flow rate, and the pressure of the fluid at zero flow rate when the current position of the movable member prevents the current flow rate from being measured by the ultrasonic measuring device.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic fluid tables. Background Technology

[0002] An ultrasonic fluid meter typically comprises a conduit through which fluid flows, and an ultrasonic measuring device including an upstream transducer (on the network side) and a downstream transducer (on the user facility side). Each transducer sequentially acts as both a transmitter and a receiver of ultrasonic signals. Thus, the upstream transducer transmits an ultrasonic signal into the conduit, which travels along a predefined path (of precisely known length) in the fluid before being received by the downstream transducer. The downstream transducer then transmits an ultrasonic signal, which travels along the same predefined path (in the opposite direction) in the fluid before being received by the upstream transducer. The ultrasonic measuring device then assesses the fluid velocity based on the time of flight of the ultrasonic signal between the transducers. Estimating the fluid velocity makes it possible to assess the amount of fluid consumed and to bill it.

[0003] In some countries, meters must be able to limit, regulate, and shut off fluid flow rates. For example, in some countries, and in the case of unpaid water bills, water distributors must provide a minimum flow rate for a certain number of days to the "bad payer" end customer before completely cutting off water access.

[0004] This minimum flow rate can vary depending on the country and the customer, and therefore it is necessary to have the possibility of adjusting the flow rate "on demand": the flow rate must be adjusted according to the flow rate setpoint.

[0005] To regulate flow rate, a proposal has been made to integrate an electric ball valve into the instrument piping. The angular position of the ball can be remotely controlled to regulate the flow rate.

[0006] However, the size of the instrument must be limited, and it may be necessary to position the valve in the flow rate measurement zone, i.e., between the two transducers.

[0007] However, when the valve is not fully open, the ultrasonic signal cannot travel in the pipe normally and follow the predefined path.

[0008] Therefore, it is impossible to measure and adjust the flow rate at certain angular positions of the ball. Summary of the Invention

[0009] The purpose of this invention is to be able to measure and regulate the flow rate of a fluid regardless of the state of the valve in the ultrasonic fluid meter (open, closed, partially open), the fluid meter comprising a conduit in which the fluid flows and a valve located in the conduit.

[0010] To achieve this objective, an ultrasonic fluid gauge is provided, comprising:

[0011] A pipe through which fluids can flow;

[0012] An ultrasonic measuring device comprising two transducers arranged in a pipe to transmit and receive ultrasonic signals, the ultrasonic measuring device being arranged to assess the current flow rate of a fluid based on the time of flight of the ultrasonic signals between the transducers;

[0013] A valve positioned between two transducers along the length of the pipe includes a movable member (14) that extends in the pipe and whose current position can be adjusted to control the current flow rate of the fluid.

[0014] A position sensor configured to measure the current position of a movable component;

[0015] A pressure sensor, arranged to measure the pressure of fluid in a pipe.

[0016] A processing unit is arranged to evaluate the current flow rate based on the current position of the movable member, the pressure of the fluid at the current flow rate, and the pressure of the fluid at zero flow rate, when the current position of the movable member makes the current flow rate unmeasurable by an ultrasonic measuring device.

[0017] Therefore, in the instrument of the present invention, when the moving component of the valve blocks the pipeline, rendering the ultrasonic equipment inoperable, the pressure measurement generated by the pressure sensor can be used to assess and regulate the current fluid flow rate.

[0018] In one embodiment, the pressure sensor is located upstream of the valve.

[0019] In one embodiment, to evaluate the pressure of a fluid at zero flow rate, the processing circuit is configured to:

[0020] Open the valve fully;

[0021] Use ultrasonic measuring equipment to measure the current flow rate;

[0022] Wait until the current flow rate becomes zero;

[0023] Then, at least one pressure measurement generated by the pressure sensor is acquired.

[0024] In one embodiment, to evaluate the pressure of a fluid at zero flow rate, the processing circuit is configured to:

[0025] Close the valve completely;

[0026] Then, at least one pressure measurement generated by the pressure sensor is acquired.

[0027] In one embodiment, the processing unit is arranged to use the pressure of the fluid to combine the measurement of the current flow rate of the fluid generated by the ultrasonic measuring device when the current flow rate is at the current position of the moving member such that it can be measured by the ultrasonic measuring device.

[0028] In one embodiment, the fluid is a compressible fluid, and the fluid gauge further includes a temperature sensor configured to measure the temperature of the fluid in the pipe. The processing circuitry is configured such that if the current position of the movable member makes the current flow rate unmeasurable by an ultrasonic measuring device, the processing circuitry also uses the temperature of the fluid to assess the current flow rate.

[0029] In one embodiment, the valve is a ball valve.

[0030] A method for measuring the current flow rate of a fluid is also provided, the method being executed in the processing circuit of the ultrasonic fluid meter as described above, and the method including the step of evaluating the current flow rate based on the current position of the movable member, the pressure of the fluid at the current flow rate, and the pressure of the fluid at zero flow rate if the current position of the movable member makes the current flow rate unmeasurable by the ultrasonic measuring device.

[0031] In one embodiment, if the current position of the movable member allows the current flow velocity to be measured by an ultrasonic measuring device, then the measurement method described above includes the following steps:

[0032] Measure the current position of the movable component;

[0033] Open the valve fully;

[0034] Use ultrasonic measuring equipment to measure the current flow rate;

[0035] Wait until the current flow rate becomes zero;

[0036] Then, at least one pressure measurement generated by the pressure sensor is acquired, and the pressure of the fluid at zero flow rate is evaluated.

[0037] Return the movable component to its current position;

[0038] Then, at least one pressure measurement generated by the pressure sensor is acquired, thereby assessing the pressure of the fluid at the current flow rate;

[0039] The current flow rate is assessed based on the current position of the moving component, the pressure of the fluid at the current flow rate, and the pressure of the fluid at zero flow rate.

[0040] In one embodiment, the measurement method described above further includes the following steps:

[0041] Detect the time interval that extends between time t1 and time t2, such that:

[0042] At time t1, the pressure value of the fluid changes from a value equal to the network pressure to another value;

[0043] At time t2, the pressure of the fluid changes again to be equal to the pressure of the network.

[0044] Integrate the current flow rate over the time interval [t1; t2] to calculate the volume consumed.

[0045] Additionally, a computer program is provided that includes instructions for causing the processing unit of the instrument described above to execute the steps of the detection method described above.

[0046] A computer-readable storage medium is also provided that stores the aforementioned computer program.

[0047] In addition, a method for adjusting the current flow rate is proposed, which is executed in the processing circuit of the ultrasonic fluid table as described above, and includes the following steps:

[0048] Collect flow rate setpoint;

[0049] Estimate the current flow rate using the measurement method described above;

[0050] The current position of the movable component is adapted based on the difference between the flow rate setpoint and the current flow rate.

[0051] A computer program is also provided, which includes instructions that cause the processing unit of the instrument described above to perform the steps of the adjustment method described above.

[0052] A computer-readable storage medium is also provided that stores the aforementioned computer program.

[0053] The invention will be best understood from the following description of specific, non-limiting embodiments thereof. Attached Figure Description

[0054] The accompanying drawings will be referenced, in which:

[0055] [ Figure 1 ] Figure 1 An ultrasonic fluid table according to a first embodiment of the present invention is shown;

[0056] [ Figure 2 ] Figure 2 Two transducers in the pipe are shown schematically;

[0057] [ Figure 3 ] Figure 3 A table for the second reference table is shown;

[0058] [ Figure 4] Figure 4 The steps of the measurement method are shown;

[0059] [ Figure 5 ] Figure 5 A graph showing the flow rate variation as a function of valve opening angle for different network pressure values ​​is shown.

[0060] [ Figure 6 ] Figure 6 A table for the third reference table is shown;

[0061] [ Figure 7 ] Figure 7 The steps of the adjustment method are shown;

[0062] [ Figure 8 ] Figure 8 A graph showing the speed of sound in water as a function of pressure at 20°C is presented.

[0063] [ Figure 9 ] Figure 9 A graph showing the pressure changes measured in the pipes when the facility started and subsequently stopped consuming water is shown;

[0064] [ Figure 10 ] Figure 10 An ultrasonic fluid table according to a second embodiment of the present invention is shown;

[0065] [ Figure 11 ] Figure 11 An ultrasonic fluid table according to a third embodiment of the present invention is shown. Detailed Implementation

[0066] refer to Figure 1 and Figure 2 The present invention is embodied in an ultrasonic water meter 1. Here, meter 1 is a water meter used to measure the water consumption of a subscriber's facility 2. Water is supplied to the subscriber's facility 2 by a distribution network 3.

[0067] Table 1 includes pipe 4, through which water supplied from network 3 to facility 2 flows. Water in pipe 4 flows from upstream to downstream, as indicated by arrow F. Here, the term "upstream" refers to one side of network 3, and the term "downstream" refers to one side of facility 2.

[0068] Instrument 1 includes processing circuitry 5. Processing circuitry 5 includes at least one processing component 5a, which is, for example, a "general purpose" processor, a processor dedicated to signal processing (or a digital signal processor (DSP)), a microcontroller, or a programmable logic circuit such as an FPGA (or field-programmable gate array) or an ASIC (or application-specific integrated circuit). Processing circuitry 5 also includes one or more memories 5b connected to or integrated into processing component 5a. At least one of these memories 5b forms a computer-readable storage support, on which at least one computer program is stored, the computer program including instructions to cause processing component 5a to perform at least some steps of the measurement and adjustment methods described below.

[0069] Instrument 1 also includes an ultrasonic measuring device 6. The ultrasonic measuring device 6 is used "by default" to measure the flow rate of water supplied to facility 2 via network 3.

[0070] The ultrasonic measuring device 6 includes an upstream transducer 7a and a downstream transducer 7b. The ultrasonic measuring device 6 also includes a measuring module 9 connected to the upstream transducer 7a and the downstream transducer 7b. Here, the processing module 9 is implemented in the processing circuit 5.

[0071] The upstream transducer 7a and the downstream transducer 7b are (but not necessarily) paired. In this example, the upstream transducer 7a and the downstream transducer 7b are piezoelectric transducers.

[0072] Each transducer 7a and 7b successively acts as a transmitter and receiver of ultrasonic signals.

[0073] Processor module 9 generates an electrical excitation signal and delivers it to the transmitter. The transmitter then generates an ultrasonic signal. The receiver receives the ultrasonic signal after it has traveled along a predetermined path 10 in the fluid, and processing module 9 measures the time of flight.

[0074] Predefined path 10 is a straight path here (inclined relative to the longitudinal axis of pipe 4, as shown in...). Figure 1 In the case of, or parallel to the axis, such as in Figure 2 (The case in the middle). The predefined path 10 has a very precisely known length d.

[0075] Therefore, firstly, the upstream transducer 7a transmits an ultrasonic signal that is received by the downstream transducer 7b. The processing module 9 measures the time of flight (TOF) from upstream to downstream. UP .

[0076] Next, downstream transducer 7b transmits the ultrasonic measurement signal received by upstream transducer 7a. Processing module 9 measures the time of flight (TOF) from downstream to upstream. DN .

[0077] We have:

[0078]

[0079]

[0080] Where c is the speed of sound in water, d is the length of the predefined path 10, and v fluid It refers to the flow rate of the water.

[0081] Now we define Δ TOF and Σ TOF :

[0082] Δ TOF =TOF DN -TOF UP

[0083] Σ TOF =TOF DN +TOF UP

[0084] Processing module 9 calculates the speed of sound by averaging the two flight times (outward and return), a speed of sound independent of fluid flow:

[0085]

[0086] The processing module calculates the water flow rate as follows:

[0087]

[0088]

[0089]

[0090] For example, temperature can be calculated from the speed of sound via a polynomial approximation, without considering pressure (if it is not measured):

[0091]

[0092] Based on this data, the water flow velocity Q is calculated as follows:

[0093]

[0094] Factor K T It is uniform at the surface, and particularly relevant to the cross-section of pipe 4. Factor K T It is derived from a first reference table based on the water temperature. The first reference table is stored in the memory 5b of the processing circuit 5. For the measured Δ... TOF Temperature is calculated using the speed of sound. Then, K is obtained as a function of the previously calculated temperature using a first reference table. T.

[0095] refer to Figure 3 To limit complex calculations (and therefore computation time and energy consumption), it is possible to use a second reference table 11 to estimate the water flow rate. For example, this second reference table 11 is two-dimensional: temperature and flow rate. The second reference table 11 is stored in the memory 5b of the processing circuit 5.

[0096] Here, the second reference table 11 consists of a single table.

[0097] As an example, if the temperature equals T1, and if Δ TOF Equal to ΔTOF 11 Then, processing module 9 will deduce from it that the flow rate is equal to D1.

[0098] Instrument 1 also includes valve 12, which makes it possible to regulate, restrict, or shut off the flow of water. Valve 12 can... Figure 1 I saw it in the middle, but Figure 2 Not shown in the image.

[0099] Valve 12 is positioned between the two transducers 7a and 7b along the length of pipe 4.

[0100] Valve 12 is an electric (electromechanical) multi-position valve. Valve 12 includes a movable member extending in pipe 4, the current position of which can be adjusted to control the current flow rate of the fluid. Here, valve 12 is a ball valve and therefore the movable member is ball 14; the current position of ball 14 is an angular position.

[0101] The counter 1 also includes a position sensor 15, which is configured to measure the current position of the ball 14.

[0102] Instrument 1 also includes a communication device that can be used to realize any type of communication, such as communication via 2G, 3G, 4G, Cat-M or NB-IoT cellular networks, communication according to the LoRa protocol, radio communication according to the Wize standard operating at a frequency of 169MHz, etc.

[0103] The communication device specifically enables the processing circuit 5 to receive the flow rate setpoint from an external source. As an example, the flow rate setpoint may be transmitted via a data concentrator by the information system (IS) of the water supplier or network administrator.

[0104] The processing circuit 5 acquires the flow rate setpoint and the current position of the ball 14 (measured by the position sensor 15), and therefore can adjust the current flow rate as necessary by modifying the angular position of the ball 14. It should be noted that the processing circuit 5 is also capable of autonomously controlling the valve 12 (i.e., without receiving an external setpoint). It should also be noted that the valve 12 can be managed via different setpoints, such as via the angular position setpoint of the ball 14.

[0105] Instrument 1 also includes a pressure sensor 16 positioned in pipe 4. The first pressure sensor 16 is positioned here upstream of valve 12 in pipe 14, generally facing upstream transducer 7a. Pressure sensor 16 makes it possible to measure the instantaneous pressure of the fluid in pipe 4.

[0106] As shown above, the ultrasonic measuring device 6 is used by default to measure the current flow rate.

[0107] However, when valve 12 is not fully open (i.e., at certain angular positions of ball (14), there is a possibility that ball 14 will prevent the ultrasonic signal from propagating between transducers 7a and 7b: valve 12 blocks the ultrasonic field, and then the water flow rate cannot be measured by ultrasonic measuring device 6. In such cases, processing circuit 5 uses pressure sensor 16 to measure the current flow rate of water in pipe 4.

[0108] Specifically, valve 12 acts as a pressure reducing device, thereby amplifying the load drop between its inlet and its outlet.

[0109] When valve 12 is open or partially open and the current flow rate is zero, the measured pressure is the network pressure (static pressure) at that point.

[0110] With the valve closed, for a given network pressure, opening the valve will cause a pressure change (decrease): there will be a difference between the pressure at zero flow rate and the pressure with flow rate.

[0111] Changes in cross-section (pipes, valves, etc.) generate changes in velocity and thus changes in pressure. Therefore, the measured instantaneous pressure (for constant network pressure) reflects the current flow velocity.

[0112] When valve 12 is closed, the current flow rate is zero, and the measured pressure is the network pressure (static pressure) at that point.

[0113] When the current position of ball 14 makes the current flow rate impossible to be measured by ultrasonic measuring device 6, that is, when valve 12 is in the half-open position and ultrasonic measurement is impossible, processing circuit 5 evaluates the current flow rate based on the current angular position of ball 14, the pressure of fluid at the current flow rate, and the pressure of fluid at zero flow rate.

[0114] Now for reference Figure 4A more detailed description of the measurement method implemented by the processing circuit 5 in this case will now be given.

[0115] The processing circuit 5 first attempts to measure the current flow rate using the ultrasonic measuring device 6 (step E1).

[0116] Processing circuit 5 verifies whether the ultrasonic signal can travel freely between transducers 7a and 7b, and therefore verifies whether the current position of ball 14 allows the current flow velocity to be measured by ultrasonic measuring device 6 (step E2). If this is the case, processing circuit 5 uses ultrasonic measuring device 6 to measure the current flow velocity.

[0117] Otherwise, the processing circuit 5 (via position sensor 15) acquires the current angular position of ball 14: step E3.

[0118] If valve 12 is closed, the processing circuit 5 acquires at least one pressure measurement generated by the pressure sensor (step E4) and thus evaluates the water pressure at zero flow rate (step E5).

[0119] If valve 12 is partially open, the processing circuit 5 measures the current position of ball 14 (step E6).

[0120] Processing circuit 5 then fully opens the valve (to 100%): step E7.

[0121] The processing circuit therefore uses ultrasonic measuring device 6 to measure the flow rate (step E8).

[0122] Processing circuit 5 waits until the current flow rate is zero (step E9).

[0123] When the current flow rate is zero, the processing circuit 5 acquires at least one pressure measurement generated by the pressure sensor and thus evaluates the water pressure at zero flow rate (step E10).

[0124] Processing circuit 5 then returns ball 14 to its initial position (i.e., to the current position): step 11.

[0125] The processing circuit 5 then acquires at least one pressure measurement generated by the pressure sensor 16, and thus assesses the pressure of the water at the current flow rate. The processing circuit 5 then estimates the current flow rate based on the current position of the ball 14, the pressure of the water at the current flow rate, and the pressure of the water at zero flow rate (step E12).

[0126] Using the following assumption: compared with the measurement frequency of network pressure 3, the static pressure PS of network 3 does not change or changes only slightly, then the difference ΔP (ΔP = PS - PI) between network pressure PS and instantaneous pressure is in fact a reflection of the current flow rate.

[0127] Figure 5The diagram shows how the flow rate changes according to the angular position of the ball 14 of valve 12 for different network pressure values: curve C1 corresponds to a network pressure of 16 bar, curve C2 corresponds to a pressure of 6 bar, and curve C3 corresponds to a pressure of 1 bar.

[0128] refer to Figure 6 In order to estimate the current flow rate, the processing circuit 5 then uses the third reference table 18 stored in the memory 5b of the processing circuit 5.

[0129] The third reference table 18 is a three-dimensional table, which includes, for example, three tables, each associated with network stress PS: PS = 16 bar, PS = 6 bar, PS = 1 bar.

[0130] For example, if the network pressure PS = 16 bar, and ΔP = PS - PI = ΔP 31 If the angular position of the ball is θ = θ3, then the processing circuit estimates the current flow rate to be equal to D1.

[0131] It should be observed that the static pressure PS of the network is considered constant until the next measurement. The closure of valve 12 is programmed for the purpose of updating it (if necessary).

[0132] Refer again Figure 4 It should be observed that steps E7, E8, and E9 can be replaced by steps that only involve completely closing valve 12 (which may be disadvantageous to subscribers). The flow rate is then zero. Processing circuit 5 then acquires at least one pressure measurement generated by pressure sensor 16 to assess the pressure of the water at zero flow rate.

[0133] If necessary, processing circuit 5 can also adjust the current flow rate.

[0134] Therefore, now refer to Figure 7 Processing circuit 5 collects the flow rate setpoint (step E20).

[0135] Processing circuit 5 then uses the measurement method just described to measure the current flow rate, and then calculates the difference between the flow rate setpoint and the current flow rate (step E21).

[0136] The processing circuit 5 then adapts the current position of ball 14 based on the difference.

[0137] To this end, the processing circuit 5 acquires the pressure of the network (previously measured by a measurement method) – step E22, and then determines the optimal angular position of the ball 14 in the third reference table 18, which makes it possible to assign the value of the flow rate setpoint to the current flow rate (step E23).

[0138] The processing circuit 5 then adjusts valve 12 to bring ball 14 into the optimal angular position.

[0139] Then, processing circuit 5 measures the current flow rate again (step E24), and the adjustment method returns to step E21. Servo control continues until a negligible difference is obtained between the current flow rate and the flow rate setpoint.

[0140] Advantageously, if the current position of ball 14 makes the current flow rate measurable by ultrasonic measuring device 6, the processing circuit 6 can combine the measurement of the current flow rate generated by ultrasonic measuring device 6 by using the pressure of water.

[0141] As discussed above, the ultrasonic measuring device 6 uses ultrasonic signals to calculate the speed of sound in water and the flow velocity of water in pipe 4. In fact, the difference between the outward and return times of the ultrasonic signal reflects the flow velocity. The sum of the outward and return times reflects the water temperature.

[0142] In order to obtain a very accurate measurement of the flow velocity, it is preferable to know the temperature in pipe 4, the speed of sound in the water, and the pressure of the water.

[0143] Generally speaking, stress is considered negligible.

[0144] However, the speed of sound in water (as in any fluid) is, among other things, a function of temperature and pressure.

[0145] Therefore, at a constant temperature T, the speed of sound in water, c(T,P), varies as a function of pressure P, as indicated in the equations of Belogol'skii et al.:

[0146] c(T,P)=c(T,0)+M1(T)(P-0.101325)+M2(T)(P-0.101325) 2 +

[0147] M3(T)(P-0.101325) 3

[0148] c(T,0)=a 00 +a 10 T+a 20 T 2 +a 30 T 3 +a 40 T 4 +a 50 T 5

[0149] M1(T)=a 01 +a 11 T+a 21 T 2 +a 31 T 3

[0150] M2(T)=a 02 +a 12 T+a 22 T 2 +a 32 T 3

[0151] M 3 (T)=a 03 +a 13 T+a 23 T 2 +a 33 T 3

[0152] coefficient a 00 a 10 a 20 The details are provided in the appendix of this specification.

[0153] exist Figure 8 As can be seen, the speed of sound in water varies with pressure.

[0154] Therefore, at 20°C, between a medium of 1 bar and a medium of 16 bar (the maximum pressure in a residential water network), the speed of sound will vary from 1482.5 m / s to 1484.99 m / s (a difference of 2.48 m / s). This difference corresponds to a temperature difference of 0.82°C.

[0155] This difference can be obtained via the second reference table 11 ( Figure 3 This introduces the error into the flow rate calculation.

[0156] Therefore, it is advantageous to consider pressure during calibration and measurement in order to improve the characterization of the medium and the calculation of flow rate.

[0157] Therefore, it is possible to replace the second reference table 11 with a three-dimensional table, which includes... Figure 3 Similar tables exist for different predefined pressure values.

[0158] Advantageously, the processing circuit 5 can use pressure sensor 16 and a second pressure sensor 17 to assess the amount of water delivered through pipe 4.

[0159] In fact, the pressure of water will change when there is a flow velocity.

[0160] Therefore, refer to Figure 9 Processing circuit 5 detects the time interval extending between time t1 and time t2, such that:

[0161] At time t1, the water pressure value changes from a value equal to the network pressure to another value;

[0162] At time t2, the water pressure value becomes equal to the network pressure again.

[0163] At time t1, the water pressure P t1 Therefore, the water pressure P measured at time t1-1 before time t1 is different. t1-1 P t1 ≠P t1-1 Pressure P t1-1 The pressure P is equal to the network pressure PS, and time t1–1 is the time before the pressure measurement performed immediately preceding the measurement performed at time t1. At time t2, the fluid pressure P t2 It becomes equal to pressure P again t1-1 :P t2 =P t1-1 =PS.

[0164] The accuracy of this time interval [t1, t2] depends on the measurement frequency of the pressure sensor 16.

[0165] Then, processing circuit 5 integrates the current flow rate over time intervals [t1; t2] to calculate the volume consumed:

[0166]

[0167] Where Q is the current flow rate (in liters per hour).

[0168] It should be noted that the present invention can be clearly applied to fluid meters other than water meters. In particular, the fluid can be a compressible fluid (e.g., gas).

[0169] In this case, advantageously, refer to Figure 10 The ultrasonic fluid meter 101 according to a second embodiment of the present invention includes a temperature sensor 120 for the fluid. Here, the temperature sensor 120 is located upstream of the pressure sensor 116. It should be noted that... Figure 10 The attached reference numerals are Figure 1 The labels in the attached figures have been increased by the value 100.

[0170] In the case of compressible fluids, it is practically impossible to correlate pressure drop with flow rate without knowing the temperature.

[0171] Specifically, it is known that:

[0172] PV = nRT,

[0173] in:

[0174] P: Pressure (Pa);

[0175] V: Volume (m³) 3 );

[0176] n: Amount of material (mol);

[0177] R: Ideal gas constant (≈8,314 J / K / mol);

[0178] T: Absolute temperature (K).

[0179] At a given temperature, we have:

[0180]

[0181] in:

[0182] ΔP: Pressure drop;

[0183] Q: Flow rate, in liters per hour.

[0184] According to Gay-Lussac's law, at a constant volume, the pressure of a given amount of gas is directly proportional to its absolute temperature (P∝T):

[0185]

[0186] Therefore, when the absolute temperature is known to make it important to correlate flow rate with pressure drop, pressure changes can be attributed to changes in flow rate or temperature. Thus, in the case of gases, it is necessary to integrate a temperature sensor and perform these measurements at a constant temperature (if only a single temperature sensor exists).

[0187] The processing circuit 105 therefore uses a fourth reference table with four dimensions. For example, this fourth reference table corresponds to the third reference table 18, to which the fourth dimension, corresponding to temperature, is added.

[0188] Naturally, the invention is not limited to the described embodiments, but covers any variations that fall within the scope of the invention as defined by the claims.

[0189] Clearly, this invention applies regardless of the positioning and configuration of the upstream and downstream transducers. Ultrasonic signals can be emitted at any directional angle relative to the longitudinal axis of the pipe.

[0190] The predefined path between transducers does not necessarily have to be a straight path. Figure 11 An ultrasonic fluid gauge 201 according to a third embodiment is shown. Ball valve 212 is in the open position. Ultrasonic signals in conduit 204, transmitted and received by transducers 207a and 207b, are reflected by reflector 221 (e.g., a mirror oriented at 45°).

[0191] Obviously, this invention is not only applicable to water meters, but to any instrument for any fluid: gas, petroleum, oil, medicine, etc.

[0192] This valve does not necessarily need to be a ball valve. Any type of valve can be used to regulate the flow rate, such as a slide valve. The position of the movable component that regulates the flow rate does not necessarily have to be angular, but can also be axial.

[0193] The pressure sensor does not necessarily have to be located upstream of the valve; it can be located downstream. However, in this case, the measured pressure will not correspond to the network pressure when the valve is fully closed.

[0194] appendix:

[0195] The following table contains the coefficients used in the equations of Belogol'skii et al.:

[0196] <![CDATA[a 00 ]]> 1402.38744 <![CDATA[a 10 ]]> 5.03836171 <![CDATA[a 20 ]]> <![CDATA[-5.81172916×10 -2 ]]> <![CDATA[a 30 ]]> <![CDATA[3.34638117×10 -4 ]]> <![CDATA[a 40 ]]> <![CDATA[-1.48259672×10 -6 ]]> <![CDATA[a 50 ]]> <![CDATA[3.16585020×10 -9 <!-- 9 -->]]> <![CDATA[a 01 ]]> 1.49043589 <![CDATA[a 11 ]]> <![CDATA[1.077850609×10 -2 ]]> <![CDATA[a 21 ]]> <![CDATA[-2.232794656×10 -4 ]]> <![CDATA[a 31 ]]> <![CDATA[2.718246452×10 -6 ]]> <![CDATA[a 02 ]]> <![CDATA[4.31532833×10 -3 ]]> <![CDATA[a 12 ]]> <![CDATA[-2.938590293×10 -4 ]]> <![CDATA[a 22 ]]> <![CDATA[6.822485943×10 -6 ]]> <![CDATA[a 32 ]]> <![CDATA[-6.674551162×10 -8 ]]> <![CDATA[a 03 ]]> <![CDATA[-1.852993525×10 -5 ]]> <![CDATA[a 13 ]]> <![CDATA[1.481844713×10 -6 ]]> <![CDATA[a 23 ]]> <![CDATA[-3.940994021×10 -8 ]]> <![CDATA[a 33 ]]> <![CDATA[3.939902307×10 -10 ]]>

Claims

1. An ultrasonic fluid meter (1), comprising: Pipe (4), in which fluid can flow; An ultrasonic measuring device (6) includes two transducers (7a, 7b) arranged in the pipe to transmit and receive ultrasonic signals, the ultrasonic measuring device being arranged to evaluate the current flow rate of the fluid based on the time of flight of the ultrasonic signals between the transducers; A valve (12) positioned between the two transducers along the length of the pipe, the valve including a movable member (14) extending in the pipe and adjustable in position to control the current flow rate of the fluid; A position sensor (15) is configured to measure the current position of the movable member; A pressure sensor (16) is arranged to measure the pressure of the fluid in the pipe; The fluid meter is characterized in that it further includes: The processing circuit (5) is arranged to evaluate the current flow rate based on the current position of the movable member, the pressure of the fluid on the current flow rate, and the pressure of the fluid at zero flow rate, when the current position of the movable member makes the current flow rate unmeasurable by the ultrasonic measuring device.

2. The ultrasonic fluid table as described in claim 1, characterized in that, The pressure sensor (16) is located upstream of the valve (12).

3. The ultrasonic fluid table as described in any one of claims 1 to 2, characterized in that, The processing circuit (5) is configured to evaluate the pressure of the fluid at zero flow rate to: Fully open the valve (12); The ultrasonic measuring device (6) is used to measure the current flow rate; Wait until the current flow rate becomes zero; Then at least one pressure measurement generated by the pressure sensor (16) is acquired.

4. The ultrasonic fluid table as described in claim 2, characterized in that, The processing circuit is configured to evaluate the pressure of the fluid at zero flow rate to: Fully close the valve (12); Then at least one pressure measurement generated by the pressure sensor (16) is acquired.

5. The ultrasonic fluid table as described in claim 1, characterized in that, The processing circuit (5) is arranged such that when the current flow rate can be measured by the ultrasonic measuring device (6) at the current position of the movable member (14), the pressure of the fluid is used to combine the measurement of the current flow rate of the fluid generated by the ultrasonic measuring device.

6. The ultrasonic fluid table as described in claim 1, characterized in that, The fluid is a compressible fluid, and the ultrasonic fluid meter (1) further includes a temperature sensor (120) configured to measure the temperature of the fluid in the pipe. The processing circuit is configured such that if the current position of the movable member prevents the ultrasonic measuring device from measuring the current flow rate, the processing circuit also uses the temperature of the fluid to assess the current flow rate.

7. The ultrasonic fluid table as described in claim 1, characterized in that, The valve (12) is a ball valve.

8. A method for measuring the current flow rate of a fluid, the method being performed in the processing circuit (5) of an ultrasonic fluid meter as claimed in any one of claims 1 to 7, and the method comprising the step of evaluating the current flow rate based on the current position of the movable member (14), the pressure of the fluid at the current flow rate, and the pressure of the fluid at zero flow rate if the current position of the movable member (14) prevents the ultrasonic measuring device (6) from measuring the current flow rate.

9. The method as described in claim 8, characterized in that, If the current position of the movable member enables the current flow velocity to be measured by the ultrasonic measuring device, then the method includes the following steps: Measure the current position of the movable component (14); Fully open the valve (12); The ultrasonic measuring device (6) is used to measure the current flow rate; Wait until the current flow rate becomes zero; At least one pressure measurement generated by the pressure sensor (16) is acquired, and the pressure of the fluid at zero flow rate is thus evaluated; Return the movable component to its current position; Then at least one pressure measurement generated by the pressure sensor is acquired, and the pressure of the fluid at the current flow rate is thus evaluated; The current flow rate is evaluated based on the current position of the movable member, the pressure of the fluid at the current flow rate, and the pressure of the fluid at zero flow rate.

10. The method according to any one of claims 8 to 9, characterized in that, It also includes the following steps: Detect the time interval that extends between time t1 and time t2, such that: At time t1, the pressure value of the fluid changes from a value equal to the pressure of the distribution network to another value; At time t2, the pressure of the fluid changes again to be equal to the pressure of the distribution network; Integrate the current flow rate over time intervals [t1; t2] to calculate the volume consumed.

11. A computer program product comprising instructions for causing a processing circuit (5) of an ultrasonic fluid table as claimed in any one of claims 1 to 7 to perform the steps of the method as claimed in any one of claims 8 to 10.

12. A computer-readable recording medium having a computer program recorded thereon, the computer program comprising instructions for causing the processing circuit (5) of the ultrasonic fluid table as claimed in any one of claims 1 to 7 to perform the steps of the method as claimed in any one of claims 8 to 10.

13. A method for regulating the current flow rate of a fluid, said method being performed in the processing circuit (5) of the ultrasonic fluid meter (1) as claimed in any one of claims 1 to 7, and comprising the steps of: Collect flow rate setpoint; The current flow rate is estimated using the method described in any one of claims 8 to 10; The current position of the movable component is adapted based on the difference between the flow rate setpoint and the current flow rate.

14. A computer program product comprising instructions for causing a processing circuit (5) of an ultrasonic fluid table as described in any one of claims 1 to 7 to perform the steps of the method as described in claim 13.

15. A computer-readable storage medium having a computer program stored thereon, the computer program comprising instructions for causing the processing circuit (5) of the ultrasonic fluid table as claimed in any one of claims 1 to 7 to perform the steps of the method as claimed in claim 13.

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