An ultrasonic metering structure, metering method and meter based on reciprocity

Abstract

The application relates to the technical field of ultrasonic metering, and particularly discloses an ultrasonic metering structure, a metering method and a meter based on reciprocity, the metering structure comprising a measuring pipe section, a first transducer and a second transducer, the first transducer and the second transducer being used for receiving or emitting ultrasonic pulses; two ports of the measuring pipe section are communicated through parallel first pipes and second pipes, an inlet is arranged on the first pipe to enable a metering object to enter the measuring pipe section, first valve bodies and second valve bodies are respectively arranged on the first pipe on the two sides of the inlet; an outlet is arranged on the second pipe to enable the metering object to be discharged from the measuring pipe section, third valve bodies and fourth valve bodies are respectively arranged on the second pipe on the two sides of the outlet. The metering method adopts the metering structure as mentioned above. The ultrasonic meter adopts the ultrasonic metering method based on reciprocity as mentioned above. The application has reasonable structure, ingenious design, greatly improved measuring precision and reduced production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic metering, in particular to an ultrasonic metering structure, metering method and meter based on reciprocity. BACKGROUND

[0002] An ultrasonic meter, such as an ultrasonic water meter, gas meter and the like, has the advantages of high metering accuracy, good reliability, small pressure loss and the like. However, in the application process of the ultrasonic meter, due to the influence of the transducer performance, the pipe segment machining precision and the metering circuit, when the medium does not flow and the slight flow caused by the thermal motion of molecules can be ignored, there is still a certain time difference between the ultrasonic pulses emitted by the same pair of transducers in the forward direction and the reverse flow direction, forming a zero drift, which further affects the metering accuracy. In addition, due to the different speeds of ultrasonic pulses in the medium at different temperatures, the uplink and downlink time difference obtained when the temperature changes also has a certain deviation, forming a temperature drift. Moreover, the zero drift and temperature drift characteristics of different ultrasonic meters of the same batch are not completely consistent. Therefore, even if the metering compensation is made for a certain specification of ultrasonic meter, it is difficult to take into account the difference in the zero drift or temperature drift characteristics between the meters based on different batches.

[0003] In addition, in production practice, there are often a certain proportion of bubbles mixed in the pipeline. When the ultrasonic wave passes through the reflection surface of the liquid and gas, reflection phenomenon occurs, causing the received amplitude of the sound wave to become smaller and the received waveform to be distorted. In the case of a smaller received amplitude of the ultrasonic wave and a distorted received waveform, the ultrasonic metering often has a zero drift, and even a jumping phenomenon, which causes the measured value of the ultrasonic water meter to deviate from the actual value, resulting in a water meter reading error or even a wrong reading.

[0004] In the prior art, the zero drift is generally completed by zero-flow calibration during the factory process, and the temperature drift is generally compensated by measuring the influence of temperature on the measurement accuracy and the size of the temperature drift. However, the zero-flow calibration of the ultrasonic water meter increases the workload of the calibration personnel in the actual production process, resulting in an increase in production cost and labor cost, and the cumbersome workload in the calibration process is also not conducive to improving production efficiency.

[0005] It is well known that in ultrasonic meters, "reciprocity" is a core physical principle that guarantees that the difference in propagation time of an ultrasonic signal in a fluid when propagating downstream and upstream is determined only by the flow velocity of the fluid and is not affected by changes in the speed of sound itself. For the design of ultrasonic meters reciprocity, the prior art often uses matching circuits to compensate for changes in the physical characteristics of the transducer, and by designing related filter circuits to achieve the reciprocity of ultrasonic signal excitation and reception, but such methods generally only achieve partial reciprocity of the circuit, which can reduce the error caused by drift when used to solve the problem of zero drift or temperature drift, as shown in the patent document with the application number CN201710036416.2 entitled "A circuit design method for eliminating the zero drift of a gas ultrasonic flowmeter".

[0006] In production practice, ultrasonic meters will inevitably be aged and contaminated during use, at which time the physical characteristics of the transducer will have shifted significantly from the initial physical characteristics, and even if calibration or compensation is performed at the factory, secondary calibration is still required. The use of matching circuits alone often results in significant measurement errors, which is not conducive to improving measurement accuracy. SUMMARY

[0007] The present application discloses an ultrasonic metering structure, metering method and meter based on reciprocity, which solves the technical problems of low measurement accuracy caused by zero drift or temperature drift in the prior art, or time-consuming and labor-intensive calibration that is not conducive to improving production efficiency, and has the technical effects of reasonable structure, ingenious design, significantly improved measurement accuracy and reduced production cost. The technical solutions adopted are as follows:

[0008] An ultrasonic metering structure based on reciprocity, comprising a measurement pipe section, a first transducer and a second transducer, the first transducer and the second transducer being used to receive or transmit ultrasonic pulses;

[0009] The two ports of the measurement pipe section are connected by parallel first and second pipelines, the first pipeline is provided with an inlet for the metering object to enter the measurement pipe section, and the first and second pipelines on both sides of the inlet are respectively provided with first and second valve bodies; the second pipeline is provided with an outlet for the metering object to be discharged from the measurement pipe section, and the second pipeline on both sides of the outlet is respectively provided with third and fourth valve bodies.

[0010] On the basis of the above technical solution, a controller is further included, the first, second, third and fourth valve bodies are respectively electrically connected to the controller, and the first and third valve bodies are linked and designed to allow the metering object to flow from the first transducer to the second transducer; the second and fourth valve bodies are linked and designed to allow the metering object to flow from the second transducer to the first transducer.

[0011] On the basis of the above technical solution, the first transducer and the second transducer are symmetrically arranged.

[0012] On the basis of the above technical solution, further comprising a first storage area, a second storage area and a third storage area; the first storage area is designed to store the flow information of the metering object flowing from the first transducer to the second transducer, the second storage area is designed to store the flow information of the metering object flowing from the second transducer to the first transducer, and the third storage area is designed to store the flow information stored in the first storage area after metering with the flow information stored in the second storage area.

[0013] An ultrasonic metering method based on reciprocity, using the metering structure as described above, comprising the steps of:

[0014] S1, constructing a forward flow model and metering a first instantaneous flow, calling the first instantaneous flow and obtaining the cumulative flow Q1 of the metering object flowing from the first transducer to the second transducer within a set time T1;

[0015] The construction of the forward flow model comprises the steps of:

[0016] S11, preparing a plurality of ultrasonic meters of the same specification;

[0017] S12, in the plurality of ultrasonic meters of the same specification, the metering object flows from the first transducer to the second transducer in a constant temperature environment on a calibrated calibration table, and the flow coefficient is obtained as a function of the flow in the measuring pipe section ;

[0018] Calling the function , metering the first instantaneous flow: ;

[0019] K1 is the flow coefficient in the forward flow model, i.e. the proportional coefficient of converting linear flow velocity to surface flow velocity in the forward flow model;

[0020] D is the inner diameter of the measuring pipe section;

[0021] C0 is the ultrasonic pulse sound speed;

[0022] is the up-down travel time difference of ultrasonic pulse when the metering object flows from the first transducer to the second transducer;

[0023] L is the effective sound path of ultrasonic pulse in the measuring pipe section;

[0024] S2, switching the metering object in the ultrasonic meter to flow from the second transducer to the first transducer, constructing a reverse flow model and metering a second instantaneous flow rate, and obtaining a cumulative flow rate Q2 of the metering object flowing from the second transducer to the first transducer within a set time T2;

[0025] The construction of the reverse flow model comprises the steps of:

[0026] S21, preparing a plurality of ultrasonic meters of the same specification;

[0027] S22, on a calibrated calibration table, flowing the metering object from the second transducer to the first transducer in the plurality of ultrasonic meters of the same specification, and obtaining a function of the flow coefficient with respect to the flow rate in the measuring pipe section ;

[0028] calling the function to meter the second instantaneous flow rate: ;

[0029] K2 is the flow coefficient in the reverse flow model, i.e. the proportional coefficient for converting linear flow velocity to surface flow velocity in the measuring pipe section in the reverse flow model;

[0030] D is the inner diameter of the measuring pipe section;

[0031] C0 is the ultrasonic pulse sound speed;

[0032] is the up-down travel time difference of the ultrasonic pulse when the metering object flows from the second transducer to the first transducer;

[0033] L is the effective sound path of the ultrasonic pulse in the measuring pipe section;

[0034] S3, calling the cumulative flow rate Q1 within the set time T1, calling the cumulative flow rate Q2 within the set time T2, obtaining the cumulative flow rate Q1+Q2 of the time T1+T2, taking the cumulative flow rate Q1+Q2 as the cumulative flow rate Q31 within the set time T1+T2, and storing.

[0035] On the basis of the above technical solution, after the cumulative flow rate Q31 is stored, T1, Q1, T2 and Q2 are cleared, and steps S1, S2 and S3 are repeated to obtain and store the cumulative flow rate Q32.

[0036] On the basis of the above technical solution, in the process of constructing the forward flow model and metering the first instantaneous flow rate, when the function of the flow coefficient with respect to the flow rate in the measuring pipe section is obtained, a plurality of continuous and different flow points are set, and the number of measurements for each flow point is not less than 3 times; in the process of constructing the reverse flow model and metering the second instantaneous flow rate, when the function of the flow coefficient with respect to the flow rate in the measuring pipe section At this time, a plurality of continuous and different flow points are set, and the number of times of measurement for each flow point is not less than 3 times.

[0037] On the basis of the above technical solution, a least square method is used to obtain a linear function and a linear function .

[0038] On the basis of the above technical solution, the flow range of the ultrasonic meter is divided into a plurality of flow sections, for each flow section, a segmented function of the flow coefficient with respect to the flow in the measurement pipe section is obtained or a segmented function .

[0039] On the basis of the above technical solution, the time interval of switching between the forward flow model and the reverse flow model is not less than 10 minutes.

[0040] On the basis of the above technical solution, T1=T2.

[0041] An ultrasonic meter using the reciprocity-based ultrasonic metering method as described above, comprising:

[0042] A metering structure comprising a measurement pipe section, a first transducer and a second transducer, the first transducer and the second transducer being used to receive or transmit ultrasonic pulses; two ports of the measurement pipe section are connected through parallel first and second pipelines, the first pipeline is provided with an inlet for the metering object to enter the measurement pipe section, the first pipeline on both sides of the inlet is respectively provided with a first valve body and a second valve body; the second pipeline is provided with an outlet for the metering object to be discharged from the measurement pipe section, the second pipeline on both sides of the outlet is respectively provided with a third valve body and a fourth valve body;

[0043] A storage unit for storing a function of the flow coefficient with respect to the flow in the measurement pipe section in the forward flow model and a function of the flow coefficient with respect to the flow in the measurement pipe section in the reverse flow model .

[0044] An acquisition unit for acquiring the ultrasonic pulse up-down travel time difference in the forward flow model and the ultrasonic pulse up-down travel time difference in the reverse flow model .

[0045] A metering unit for metering the first instantaneous flow in the forward flow model and for metering the second instantaneous flow in the reverse flow model.

[0046] Advantages

[0047] The ultrasonic metering structure in the application, two ports of the measuring pipe section are communicated through the parallel first pipeline and the second pipeline respectively, and by controlling the on-off of the four valve bodies, the flow of the metering object from the first transducer to the second transducer or from the second transducer to the first transducer can be controlled.

[0048] In the ultrasonic metering method in the application, the bidirectional model, i.e. the forward flow model and the reverse flow model, is constructed, in the forward flow model, the corresponding flow coefficient is obtained as a function of the flow in the measuring pipe section , and then the first instantaneous flow and the cumulative flow Q1 are obtained; in the reverse flow model, the corresponding flow direction coefficient is obtained as a function of the flow in the measuring pipe section , and then the second instantaneous flow and the cumulative flow Q2 are obtained, and then the cumulative flow Q1 obtained in the forward flow model and the cumulative flow Q2 obtained in the reverse flow model are added as the cumulative flow Q31 in the T1+T2 time period and stored.

[0049] The ultrasonic metering method in the application is simple and easy to operate and reliable in operation, the functions and are obtained, the number of times of measuring the flow coefficient for each flow point is not less than 3 times, so that the function of the flow coefficient as a function of the flow in the measuring pipe section can more accurately reflect the relationship between the flow coefficient and the flow in the measuring pipe section; further, based on multiple flow sections, for each flow section, a segmented function of the flow coefficient as a function of the flow in the measuring pipe section is obtained, so that the function can further accurately reflect the relationship between the flow coefficient and the flow in the measuring pipe section, and then it is beneficial to more accurately compensate the drift amount and improve the measurement accuracy.

[0050] The time interval of switching the forward flow model and the reverse flow model in the application is not less than 10 minutes, which can effectively reduce the metering error caused by model switching and is beneficial to further improve the measurement accuracy.

[0051] The ultrasonic meter disclosed in the present application is designed based on reciprocity, which can effectively solve the problems of zero drift and temperature drift of the ultrasonic meter, thereby reducing the workload of calibration or supplement of the debugging personnel before leaving the factory, lowering the labor cost, and improving the production efficiency. Moreover, in the case of aging and contamination of the ultrasonic meter during use, the secondary correction can be completed by updating the function of the flow coefficient in the forward flow model and the reverse flow model with respect to the flow in the measuring pipe section, thereby improving the service life of the ultrasonic meter and lowering the use cost. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only one embodiment of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0053] Figure 1 : Structure diagram of the measuring pipe section of the ultrasonic water meter in the present application;

[0054] Figure 2 : Schematic diagram of the metering structure in the present application;

[0055] Figure 3 : Schematic diagram of the metering method flow in the present application;

[0056] The drawings are as follows: 1-First transducer; 2-Second transducer; 3-Measuring pipe section; 10-First valve body; 20-Second valve body; 30-Third valve body; 40-Fourth valve body. DETAILED DESCRIPTION

[0057] In this document, the term "a plurality of" means two or more, unless otherwise specified.

[0058] In this document, the character " / " represents an "or" relationship between the front and rear objects. For example, A / B means A or B.

[0059] In this document, the term "and / or" is a description of the association relationship between objects, which means that there can be three relationships. For example, A and / or B means: A or B, or, A and B, three relationships.

[0060] Taking the ultrasonic water meter as an example, the structure of the ultrasonic water meter includes a measuring pipe section 3, a transducer group, and a metering circuit group. In the metering process, the ultrasonic water meter adopts the time difference to measure the instantaneous flow principle, which is shown as follows:

[0061] In the prior art, the water flow in the measuring pipe section 3 of the ultrasonic water meter flows in a directional flow, so that the flow coefficient is a constant value, and the flow coefficient is not affected by the flow direction. Figure 1The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example T UP The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example

[0062] (1)

[0063] The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example T DOWN The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example

[0064] (2)

[0065] The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example

[0066] (3)

[0067] According to formula (3), if the ultrasonic water meter is installed in a closed still water environment, at this time v is zero, and the theoretical time difference should be 0.

[0068] But the actual time difference collection data obtained by the actual ultrasonic water meter is not zero due to the inconsistency of the equivalent circuit of the transducer transmission and reception signal, and there is a certain zero drift error.

[0069] The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example The propagation time of the upstreaming of the ultrasonic pulse against the flow is shown as an example (4)

[0070] That is, the formula (4) is obtained, which is the water flow line speed of the water in the measuring pipe section 3. In practice, it is necessary to convert the water flow line speed into the surface flow speed of the measuring pipe section 3 according to a certain proportional coefficient K, that is, K is the proportional coefficient for converting the water flow line speed into the surface flow speed, which is called the flow coefficient in this application, and then the instantaneous flow calculation formula of the measuring pipe section 3 is obtained:

[0071] (5)

[0072] C0 is the current propagation speed of the ultrasonic pulse in water;

[0073] v is the water flow line speed of the water in the measuring pipe section 3;

[0074] The time accumulation value contains the circuit delay, the transducer vibration delay, and the ultrasonic waveform timing delay;

[0075] The instantaneous volume flow of the water in the measuring pipe section 3 is

[0076] D is the inner diameter of the measuring pipe section 3 of the ultrasonic water meter;

[0077] for the difference between the uplink and downlink propagation times of the ultrasonic waves;

[0078] K is a flow meter coefficient, which is by default 1 in the prior art;

[0079] The application discloses an ultrasonic metering structure based on reciprocity, which comprises a measuring pipe section 3, a first transducer 1 and a second transducer 2, and the first transducer 1 and the second transducer 2 are used for receiving or emitting ultrasonic pulses. Figure 1 As shown in the figure, the first transducer 1 and the second transducer 2 are symmetrically arranged, that is, the first transducer 1 and the second transducer 2 are installed on the upstream and downstream sides of the measuring pipe section 3 in a geometrically symmetrical manner, so that the first transducer 1 and the second transducer 2 are oppositely installed at a certain angle (such as Z method, V method or W method), so that the ultrasonic pulses can propagate along a symmetrical path in the metering object.

[0080] The two ports of the measuring pipe section 3 are communicated through parallel first pipes and second pipes, the first pipes are provided with inlets for the metering object to enter the measuring pipe section 3, and the first pipes on the two sides of the inlets are respectively provided with first valve bodies 10 and second valve bodies 20.

[0081] The second pipes are provided with outlets for the metering object to be discharged from the measuring pipe section 3, and the second pipes on the two sides of the outlets are respectively provided with third valve bodies 30 and fourth valve bodies 40.

[0082] The application further comprises a controller, the first valve bodies 10, the second valve bodies 20, the third valve bodies 30 and the fourth valve bodies 40 are electrically connected with the controller, and the first valve bodies 10 and the third valve bodies 30 are linked and designed to allow the metering object to flow from the first transducer 1 to the second transducer 2; the second valve bodies 20 and the fourth valve bodies 40 are linked and designed to allow the metering object to flow from the second transducer 2 to the first transducer 1.

[0083] In the embodiment, the controller comprises a single-chip microcomputer, the first valve bodies 10, the second valve bodies 20, the third valve bodies 30 and the fourth valve bodies 40 are electrically connected with the controller, and the first valve bodies 10 and the third valve bodies 30 are controlled by a first double-pole double-throw analog switch, and the second valve bodies 20 and the fourth valve bodies 40 are controlled by a second double-pole double-throw analog switch, wherein the double-pole double-throw analog switch can adopt a high-speed and low-power double-pole double-throw analog switch produced by Ruimeng Science and Technology, with a model number of MSUSB30 / MSUSB30N, a working voltage range of +1.8V to +5.5V, and characteristics of low code offset, high channel noise isolation and wide bandwidth.

[0084] As an example, when the first double-pole double-throw analog switch controls the first valve body 10 and the third valve body 30 to open to the position, the working current of the first double-pole double-throw analog switch is cut off; at the same time, the second double-pole double-throw analog switch controls the second valve body 20 and the fourth valve body 40 to close, and the working current of the second double-pole double-throw analog switch is cut off, so that the measurement object can flow from the first transducer 1 to the second transducer 2, and the control process has good reliability and low failure rate. When it is needed to control the measurement object to flow from the second transducer 2 to the first transducer 1, the above-mentioned process is reversed.

[0085] The measurement structure in the present application further comprises a first storage area, a second storage area and a third storage area.

[0086] The first storage area is designed to store the flow information when the measurement object flows from the first transducer 1 to the second transducer 2; the second storage area is designed to store the flow information when the measurement object flows from the second transducer 2 to the first transducer 1; and the third storage area is designed to store the flow information stored in the first storage area and the flow information stored in the second storage area after measurement.

[0087] An ultrasonic measurement method based on reciprocity, using the measurement structure as described above, comprising the steps of:

[0088] S1, constructing a forward flow model and measuring a first instantaneous flow, calling the first instantaneous flow and obtaining the cumulative flow Q1 of the measurement object flowing from the first transducer 1 to the second transducer 2 within a set time T1;

[0089] The construction of the forward flow model comprises the steps of:

[0090] S11, preparing three ultrasonic meters of the same specification; in other embodiments of the present application, one, two or more can also be prepared.

[0091] S12, on a calibrated calibration table, in a normal temperature environment, among the three ultrasonic meters of the same specification, the measurement object flows from the first transducer 1 to the second transducer 2, i.e., the forward flow model is constructed, and the function of the flow coefficient with respect to the flow in the measuring pipe section 3 is obtained In this embodiment, the forward flow model is constructed and the function of the flow coefficient with respect to the flow in the measuring pipe section 3 is obtained The process can be completed before leaving the factory, and the function is stored in the meter, and the function can be called during actual use.

[0092] Specifically, for each ultrasonic meter, eight or more continuous and different flow points are set, such as Q11, Q12, Q13, Q14, Q15, Q16, Q17, and Q18, and the number of measurements for each flow point is not less than 3 times, that is, each meter is measured once for each flow point, and then the average value of the three meters is taken; wherein the flow coefficient is the proportional coefficient of converting the linear flow velocity in the measurement pipe section 3 to the surface flow velocity in the forward flow model, which is specifically reflected as the ratio of the ultrasonic meter flow value read to the standard flow on the calibration table, and thus a plurality of groups of data are obtained, (K11, Q 表11 ), (K12, Q 表12 ), (K13, Q 表13 )... (K1n, Q 表1n ), wherein the ultrasonic meter flow value read is obtained by calculation using formula (5) as described above, wherein K=1.

[0093] Then, the aforementioned plurality of groups of data are called, and a linear function is obtained by least squares fitting, in other embodiments of the present application, the flow range of the ultrasonic meter is further divided into two flow sections, for each of the flow sections, a segmented function of the flow coefficient with respect to the flow in the measurement pipe section 3 is obtained , that is, a segmented function is obtained for the flow section formed by Q11, Q12, Q13, and Q14 , and another segmented function is obtained for the flow section formed by Q15, Q16, Q17, and Q18 , which can more accurately reflect the actual instantaneous value.

[0094] The function is called, and the first instantaneous flow is measured:

[0095] ;

[0096] Specifically, first, the measured value flow value Q1 of the ultrasonic meter is read according to formula (5), wherein K=1; then the function is called, and the K1 value is calculated and obtained, and then the first instantaneous flow is measured.

[0097] K1 is the flow coefficient in the forward flow model, that is, the proportional coefficient of converting the linear flow velocity in the measurement pipe section 3 to the surface flow velocity in the forward flow model;

[0098] D is the inner diameter of the measurement pipe section 3;

[0099] C0 is the ultrasonic pulse speed;

[0100] is the up-down travel time difference of the ultrasonic pulse when the measurement object flows from the first transducer 1 to the second transducer 2;

[0101] L is the effective sound path of the ultrasonic pulse in the measurement pipe section 3 in the forward flow model;

[0102] S2, in the aforementioned metering structure, switching the metering object in the ultrasonic meter to flow from the second transducer 2 to the first transducer 1 by the controller, constructing the reverse flow model and metering the second instantaneous flow, obtaining the cumulative flow Q2 of the metering object flowing from the second transducer 2 to the first transducer 1 within a set time T2;

[0103] The construction of the reverse flow model includes the steps of:

[0104] S21, preparing three ultrasonic meters of the same specification; in other embodiments of the present application, one, two or more can also be prepared.

[0105] S22, in the ultrasonic meters of the same specification, the metering object flows from the second transducer to the first transducer 1 in a normal temperature environment on a calibrated calibration bench, that is, the reverse flow model is constructed, and the flow coefficient is obtained as a function of the flow in the measurement pipe section 3 ; in this embodiment, the process of constructing the reverse flow model and obtaining the flow coefficient as a function of the flow in the measurement pipe section 3 can be completed before leaving the factory, and the function is stored in the meter, and the function is called during actual metering.

[0106] Specifically, eight or more continuous and different flow points are set for each ultrasonic meter, such as Q21, Q22, Q23, Q24, Q25, Q26, Q27, Q28, and the number of measurements for each flow point is not less than 3 times, that is, each meter is measured once for each flow point, and then the average value of the three meters is taken; wherein the flow coefficient is the proportional coefficient of converting linear flow velocity to surface flow velocity in the measurement pipe section 3 in the forward flow model, which is specifically reflected as the ratio of the ultrasonic meter flow value to the standard flow on the calibration bench, so as to obtain multiple sets of data, (K21, Q 表21 ), (K22, Q 表22 ), (K23, Q 表23 )... (K2n, Q 表2n ).

[0107] Wherein, the ultrasonic meter flow value is calculated by formula (5) as described above, wherein K=1.

[0108] Then, the aforementioned multiple sets of data are called, and the least square method is used to fit to obtain a linear function In other embodiments of the present application, the ultrasonic meter flow range is further divided into two flow segments, for each flow segment, a segmented function of flow coefficient with respect to flow in the measuring pipe segment 3 is obtained , i.e. a segmented function for the flow segment formed by Q21, Q22, Q23, Q24 is obtained , another segmented function for the flow segment formed by Q25, Q26, Q27, Q28 is obtained , so that the actual instantaneous value can be more accurately reflected.

[0109] the function is called , and the second instantaneous flow is metered ;

[0110] Specifically, first, the measured flow value Q2 of the ultrasonic meter is read according to formula (5), wherein K=1; then the function is called , the K2 value is calculated, and the second instantaneous flow is obtained .

[0111] K2 is the flow coefficient in the reverse flow model, i.e. the proportional coefficient for converting linear flow velocity to surface flow velocity in the measuring pipe segment 3 in the reverse flow model;

[0112] D is the inner diameter of the measuring pipe segment 3;

[0113] C0 is the ultrasonic pulse speed;

[0114] is the up-down time difference of the ultrasonic pulse when the metering object flows from the second transducer 2 to the first transducer 1;

[0115] L is the effective sound path of the ultrasonic pulse in the measuring pipe segment 3 in the reverse flow model;

[0116] In the present application, the time interval for switching between the forward flow model and the reverse flow model is not less than 10 minutes, which can effectively reduce the measurement error caused by model switching and is beneficial to further improve the measurement accuracy.

[0117] S3, the cumulative flow Q1 in the set time T1 is called, the cumulative flow Q2 in the set time T2 is called, the cumulative flow Q1+Q2 of the time T1+T2 is obtained, the cumulative flow Q1+Q2 is taken as the cumulative flow Q31 in the set time T1+T2 and stored, in the present embodiment, T1=T2.

[0118] Further, after the cumulative flow Q31 is stored, T1, Q1, T2 and Q2 are cleared, and steps S1, S2 and S3 are repeated to obtain and store the cumulative flow Q32, a plurality of cumulative flows Q33, Q34...Q3n can be obtained repeatedly, and the average value is taken as the output cumulative flow for the staff to read.

[0119] The meter adopting the metering method can effectively improve the metering accuracy in the static water and constant flow environment.

[0120] Firstly, the static water environment is selected, the meter adopting the metering method and the ordinary meter of the same specification are installed on the meter calibration platform, and the meter adopting the metering method switches the forward flow model and the reverse flow model every 10 minutes. The initial flow is set to 0.5 liters / hour, and after metering, the cumulative flow of the meter adopting the metering method in half an hour is less than 0.1 liters, while the cumulative flow measured by the ordinary meter of the same specification in half an hour under the same initial flow is 10 liters, that is, the meter adopting the metering method can effectively reduce the initial flow and greatly improve the metering accuracy.

[0121] Then, the constant flow environment is selected, the meter adopting the metering method and the ordinary meter of the same specification are installed on the meter calibration platform, and the meter adopting the metering method switches the forward flow model and the reverse flow model every 10 minutes. The flow points Q 恒2 and Q 恒3 are set on the meter calibration platform, and the error of the cumulative flow of the meter in half an hour is compared with the standard flow. The error of the meter adopting the metering method is maintained within 1%, while the error of the ordinary meter exceeds 2%.

[0122] In other embodiments of the present application, when the ultrasonic meter reaches the set value, considering the inevitable aging or fouling, the flow coefficient function and about the flow in the measuring pipe section 3 can be updated and stored in the ultrasonic meter, which is designed ingeniously, so that secondary correction can be performed, which is beneficial to improve the service life of the ultrasonic meter and reduce the use cost.

[0123] An ultrasonic meter adopts the ultrasonic metering method based on reciprocity as described above, comprising:

[0124] A metering structure comprises a measuring pipe section 3, a first transducer 1 and a second transducer 2 for receiving or transmitting ultrasonic pulses; the two ports of the measuring pipe section 3 are connected through parallel first and second pipelines, the first pipeline is provided with an inlet for the metering object to enter the measuring pipe section 3, and the first and second valve bodies 10 and 20 are respectively arranged on the first pipeline on both sides of the inlet; the second pipeline is provided with an outlet for the metering object to be discharged from the measuring pipe section 3, and the third and fourth valve bodies 30 and 40 are respectively arranged on the second pipeline on both sides of the outlet;

[0125] A storage unit is used to store the function of the flow coefficient about the flow in the measuring pipe section 3 in the forward flow model flow coefficient as a function of the flow in the measuring pipe section 3 ;

[0126] an acquisition unit for acquiring the difference between the upstroke and downstroke times of the ultrasound pulse in the forward flow model and the difference between the upstroke and downstroke times of the ultrasound pulse in the reverse flow model ;

[0127] a metering unit for metering the first instantaneous flow in the forward flow model and for metering the second instantaneous flow in the reverse flow model.

[0128] The application has been described above by way of example, but is not limited to the specific embodiments described above, any modifications or variants made on the basis of the application falling within the scope of the application as claimed.

Claims

1. A reciprocity-based ultrasonic metrology method, characterized in that, The application relates to an ultrasonic metering structure based on reciprocity, which comprises a measuring pipe section (3), a first transducer (1) and a second transducer (2) for receiving or emitting ultrasonic pulses. Two ports of the measuring pipe section (3) are communicated through a first pipe and a second pipe in parallel, the first pipe is provided with an inlet for the metering object to enter the measuring pipe section (3), and the first pipe is provided with a first valve body (10) and a second valve body (20) on the two sides of the inlet respectively; the second pipe is provided with an outlet for the metering object to be discharged from the measuring pipe section (3), and the second pipe is provided with a third valve body (30) and a fourth valve body (40) on the two sides of the outlet respectively. The ultrasonic metering method comprises the following steps: S1, constructing a forward flow model and metering a first instantaneous flow, calling the first instantaneous flow and obtaining the cumulative flow Q1 of the metering object flowing from the first transducer to the second transducer within a set time T1; The construction of the forward flow model comprises the following steps: S11, preparing a plurality of ultrasonic meters of the same specification; S12, in the same type of ultrasonic meter, the flow direction of the flow object is from the first transducer (1) to the second transducer (2) on the calibrated calibration table, and the flow coefficient is obtained as a function of the flow in the measuring pipe section (3) ; Calling function , metering the first instantaneous flow rate: ； K1 is a flow coefficient in the forward flow model, that is, a proportional coefficient for converting linear flow velocity into surface flow velocity in the measuring pipe section (3) in the forward flow model; D is the inner diameter of the measuring pipe section (3); C0 is the sound velocity of the ultrasonic pulse; To measure the difference in up and down travel times of an ultrasound pulse as it flows from the first transducer (1) to the second transducer (2); L is the effective sound path of the ultrasonic pulse in the measuring pipe section (3) in the forward flow model; S2, switching the metering object in the ultrasonic meter to flow from the second transducer (2) to the first transducer (1), constructing a reverse flow model and metering a second instantaneous flow, and obtaining the cumulative flow Q2 of the metering object flowing from the second transducer (2) to the first transducer (1) within a set time T2; The construction of the reverse flow model comprises the following steps: S21, preparing a plurality of ultrasonic meters of the same specification; S22, in the same type of ultrasonic meter, the flow direction of the flow object is from the second transducer (2) to the first transducer (1) on the calibrated calibration table, and the flow coefficient is obtained as a function of the flow in the measuring pipe section (3) ; Calling function , metering the second instantaneous flow rate: ； K2 is a flow coefficient in the reverse flow model, that is, a proportional coefficient for converting linear flow velocity into surface flow velocity in the measuring pipe section (3) in the reverse flow model; D is the inner diameter of the measuring pipe section; C0 is the sound velocity of the ultrasonic pulse; to measure the difference in the up and down travel times of the ultrasound pulses as the object flows from the second transducer (2) towards the first transducer (1); L is the effective sound path of the ultrasonic pulse in the measuring pipe section (3) in the reverse flow model; S3, calling the cumulative flow Q1 within the set time T1, calling the cumulative flow Q2 within the set time T2, obtaining the cumulative flow Q1+Q2 of the time T1+T2, taking the cumulative flow Q1+Q2 as the cumulative flow Q31 within the set time T1+T2, and storing the cumulative flow Q1+Q2.

2. The reciprocity-based ultrasonic metrology method of claim 1, wherein, The ultrasonic metering structure further comprises a controller, the first valve body (10), the second valve body (20), the third valve body (30) and the fourth valve body (40) are electrically connected with the controller respectively, and the first valve body (10) and the third valve body (30) are linked and designed to allow the metering object to flow from the first transducer (1) to the second transducer (2); the second valve body (20) and the fourth valve body (40) are linked and designed to allow the metering object to flow from the second transducer (2) to the first transducer (1).

3. The reciprocity-based ultrasonic metrology method of claim 1, wherein, The first transducer (1) and the second transducer (2) are symmetrically arranged.

4. The reciprocity-based ultrasonic metrology method of claim 1, wherein, The ultrasonic metering structure further comprises a first storage area, a second storage area and a third storage area; the first storage area is designed to store flow information of the metering object flowing from the first transducer (1) to the second transducer (2), the second storage area is designed to store flow information of the metering object flowing from the second transducer (2) to the first transducer (1), and the third storage area is designed to store the flow information stored in the first storage area after metering with the flow information stored in the second storage area.

5. The reciprocity-based ultrasonic metrology method of any one of claims 1-4, wherein, The accumulated flow Q31 is stored, and then T1, Q1, T2 and Q2 are cleared, and steps S1, S2 and S3 are repeated to obtain the accumulated flow Q32 and store it.

6. The reciprocity-based ultrasonic metrology method of any one of claims 1-4, wherein, During the process of constructing the downstream model and measuring the first instantaneous flow rate, the function of obtaining the flow coefficient with respect to the flow rate in the measuring pipe section (3) is used. At the same time, multiple continuous and different flow points are set, and the number of measurements for each flow point is not less than 3; during the process of constructing the counterflow model and measuring the second instantaneous flow, the flow coefficient is obtained as a function of the flow in the measuring pipe section (3). At the same time, multiple consecutive and different flow points are set, and the number of measurements for each flow point is not less than 3.

7. The reciprocity-based ultrasonic metrology method of claim 5, wherein, A least square method is used to fit the first order function and the first order function .

8. The reciprocity-based ultrasonic metrology method of claim 5, wherein, The ultrasonic meter flow range is divided into multiple flow segments, for each flow segment, a segmented function of flow coefficient with respect to flow in the measuring pipe segment (3) is obtained or segmented function .

9. The reciprocity-based ultrasonic metrology method of claim 5, wherein, The time interval for switching the forward flow model and the reverse flow model is not less than 10 minutes.

10. The reciprocity-based ultrasonic metrology method of claim 9, wherein, The T1=T2.

11. An ultrasonic meter adopting the reciprocity-based ultrasonic metering method according to any one of claims 1-4 and 7-10, comprising: a metering structure comprising a measuring pipe section (3), a first transducer (1) and a second transducer (2), the first transducer (1) and the second transducer (2) being used to receive or emit ultrasonic pulses; two ports of the measuring pipe section (3) are communicated through parallel first and second pipelines, the first pipeline is provided with an inlet for the metering object to enter the measuring pipe section (3), and the first pipeline on both sides of the inlet is respectively provided with a first valve body (10) and a second valve body (20); the second pipeline is provided with an outlet for the metering object to be discharged from the measuring pipe section (3), and the second pipeline on both sides of the outlet is respectively provided with a third valve body (30) and a fourth valve body (40); a storage unit for storing a function of the discharge coefficient with respect to the flow rate in the measuring pipe section (3) in the forward flow model a function of the discharge coefficient with respect to the flow rate in the measuring pipe section (3) in the reverse flow model ; The acquisition unit acquires the up-down time difference of the ultrasonic pulse in the down-flow model and the up-down time difference of the ultrasonic pulse in the up-flow model ; a metering unit for metering the first instantaneous flow in the forward flow model and the second instantaneous flow in the reverse flow model.

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