CN212300539U

CN212300539U - Ultrasonic flowmeter calibration device

Info

Publication number: CN212300539U
Application number: CN202020635203.9U
Authority: CN
Inventors: 赵军华; 李丛; 张清波; 王玉霞
Original assignee: Shenzhen Hongdian Technologies Corp
Current assignee: Shenzhen Hongdian Technologies Corp
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2021-01-05
Anticipated expiration: 2030-04-22

Abstract

The utility model provides an ultrasonic flowmeter calibrating device, including the steady voltage water pitcher that is used for providing stable water pressure, the raceway that one end is connected with the steady voltage water pitcher and be used for supporting a plurality of drain pipes of waiting to mark ultrasonic flowmeter, the cross sectional shape of a plurality of drain pipes is different, the raceway includes the water main that one end is connected with the steady voltage water pitcher and a plurality of bleeder pipes that link to each other with each drain pipe respectively, each bleeder pipe is connected with the water main, install the standard flowmeter that is used for detecting water main in-flow and be used for adjusting the flow control valve of water main in-flow on the water main, install the control valve of controlling this bleeder pipe break-make on each bleeder pipe respectively. The application provides an ultrasonic flowmeter calibration device adopts the drain pipe of different cross sections, has reduced the difference when waiting to mark ultrasonic flowmeter calibration on the different drain pipes, has reduced the difference and has waited that ultrasonic flowmeter marks back flow measurement's error.

Description

Ultrasonic flowmeter calibration device

Technical Field

The application belongs to the technical field of flowmeters, and particularly relates to an ultrasonic flowmeter calibration device.

Background

In urban construction, the construction of a drainage pipe network is particularly important, and if the drainage pipe network is unreasonable in design, urban drainage efficiency is low, and urban waterlogging is easily caused. When the drainage pipe duct is designed, the drainage flow rate needs to be considered, and a certain drainage allowance is usually reserved, so that the water in the drainage pipe duct is usually in a non-full pipe state.

In order to accurately measure the drainage flow rate in the drainage pipe duct, a corresponding ultrasonic flowmeter needs to be installed. When the ultrasonic flowmeter is produced, a corresponding reference function needs to be implanted into the ultrasonic flowmeter, and a signal value of the ultrasonic flowmeter is converted into a corresponding flow value; when the ultrasonic flowmeter is installed, calibrating a reference function in the ultrasonic flowmeter according to the flow value of the actually installed pipe duct. However, due to a certain difference in cross-sectional shapes of the actual application pipes, when the reference function is applied to different pipes in the conventional calibration method, the rules of the reference function and the actual flow value may not be consistent with the signal value of the ultrasonic flow meter to be calibrated, which results in a large difference in calibration of the ultrasonic flow meter to be calibrated in different pipes and a large calibration error.

SUMMERY OF THE UTILITY MODEL

The application aims to provide an ultrasonic flowmeter calibration device, which comprises but is not limited to solving the technical problems that when an ultrasonic flowmeter calibration method in the prior art is used for calibrating ultrasonic flowmeters to be calibrated on different pipelines, calibration has large difference and calibration errors are large.

In order to solve the technical problem, an embodiment of the present application provides an ultrasonic flowmeter calibration device, which is characterized in that: the water delivery pipe comprises a pressure stabilizing water tank, a water delivery pipe and a plurality of drainage pipes, wherein the pressure stabilizing water tank is used for providing stable water outlet pressure, one end of the water delivery pipe is connected with the pressure stabilizing water tank, the drainage pipes are used for supporting an ultrasonic flowmeter to be calibrated, the cross section shapes of the drainage pipes are different, the water delivery pipe comprises a water delivery main pipe and a plurality of branch pipes, one end of each branch pipe is connected with the pressure stabilizing water tank, the branch pipes are respectively connected with the water delivery main pipe, the water delivery main pipe is provided with a standard flowmeter used for detecting the water flow in the water delivery main pipe and a flow regulating valve used for regulating the water flow in the water delivery main pipe, and each branch pipe is respectively provided with a control valve used for controlling.

Further, a liquid level sensor is arranged at the bottom of the pressure stabilizing water tank.

Furthermore, a water replenishing pipe is connected to the pressure stabilizing water tank, and a liquid level regulating valve is installed on the water replenishing pipe.

Further, the ultrasonic flowmeter calibration device further comprises a water return assembly for conveying the drainage of each drainage pipe to the pressure stabilizing water tank.

Furthermore, the water return assembly comprises a collecting tank for collecting water discharged by each water discharge pipe, a water return pipe for connecting the collecting tank with the pressure stabilizing water tank, and a reflux pump installed on the water return pipe.

Further, the reflux pump is a variable frequency pump.

The application further provides an ultrasonic flow meter calibration method, which is used for calibrating the ultrasonic flow meter to be calibrated by using the ultrasonic flow meter calibration device in any embodiment, and the ultrasonic flow meter calibration method comprises the following steps:

s1, mounting the ultrasonic flow meter to be calibrated on each water drainage pipe;

s2, controlling the water flow in the water delivery main pipe to flow out through the water discharge pipes in sequence, and controlling the water flow of the water delivery main pipe when the water flow flows through the water discharge pipes, so that a plurality of groups of flow rate values (Q) of the water discharge pipes can be obtained_{raw_value}，Q_{stan._value}) Wherein Q is_{raw_value}For the ultrasonic wave to be calibratedFlow rate value, Q, of the flowmeter_{stan._value}The standard flow value is corresponding to a standard flow meter on the water delivery main pipe;

s3, according to the multiple groups of Q in the step S2_{raw_value}And Q_{stan._value}The value of the reference function f is subjected to curve fitting to obtain a reference function f of the ultrasonic flowmeter to be calibrated_base(Q_{raw_value},Q_{stan._value})；

S4, converting the reference function f_base(Q_{raw_value},Q_{stan._value}) Implanting each ultrasonic flowmeter to be calibrated.

Further, after step S4, the method further includes:

s5, selecting the drain pipe which is close to the cross section of the application pipeline of the ultrasonic flowmeter to be calibrated, and installing the ultrasonic flowmeter to be calibrated on the drain pipe;

s6, controlling the water flow in the water delivery main pipe to be discharged through the water discharge pipe, and controlling the water flow in the water delivery main pipe to obtain a plurality of flow values Q of the ultrasonic flowmeter to be calibrated_{raw_value_i}And a standard flow value Q corresponding to a standard flow meter on the water delivery main pipe_{stan._value_i}；

S7, according to each group Q in the step S6_{raw_value_i}And Q_{stan._value_i}To the reference function f_base(Q_{raw_value},Q_{stan._value}) To obtain a calibration function f of the ultrasonic flow meter to be calibrated_cal.(Q_{raw_value},Q_{stan._value})；

S8, calibrating the reference function f in the ultrasonic flowmeter to be calibrated_base(Q_{raw_value},Q_{stan._value}) Correction to a calibration function f_cal.(Q_{raw_value},Q_{stan._value})。

Further, step S2 includes: controlling the water flow in the water delivery main pipe, and adjusting the water pressure in the pressure stabilizing water tank to stabilize the water pressure in the pressure stabilizing water tank; after the water flow pressure and the flow in the drain pipe are stable, acquiring a flow value Q of the ultrasonic flowmeter to be calibrated of the drain pipe_{raw_value_i}And, andthe standard flow value Q corresponding to the standard flowmeter on the water delivery main pipe_{stan._value_i}。

Further, step S2 includes: obtaining the flow value Q of the ultrasonic flowmeter to be calibrated_{raw_value}For the cumulative flow q of the ultrasonic flowmeter to be calibrated in the time delta t_raw.A calculated average water flow value; acquired standard flow value Q_{stan._value}Is the cumulative flow q of a standard flowmeter in time delta t_stanCalculated average water flow value.

According to the ultrasonic flowmeter calibration device and the calibration method thereof, the stable water delivery pressure is provided by the pressure stabilizing water tank, so that stable water flow can be obtained in each drain pipe; the drain pipes with different cross sections are adopted, the non-full flow data of the drain pipes with different cross sections can be obtained, and then the reference function adapting to the drain pipes with various different cross sections is calculated, so that the reference function of the ultrasonic flowmeter to be calibrated is set, the reference function in the ultrasonic flowmeter to be calibrated can be suitable for the drain pipes with different cross sections, the difference of the ultrasonic flowmeter to be calibrated on different drain pipes is reduced, and the error of flow detection of the different ultrasonic flowmeters to be calibrated is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of an ultrasonic flow meter calibration apparatus according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of an ultrasonic flowmeter calibration apparatus provided in the second embodiment of the present application;

fig. 3 is a schematic structural diagram of a calibration apparatus for an ultrasonic flow meter according to a third embodiment of the present application;

fig. 4 is a schematic view of water flow in an embodiment of the present application.

Wherein, in the figures, the respective reference numerals:

11-pressure stabilizing water tank, 21-water pipe, 21 a-water main pipe, 21 b-branch pipe, 23-standard flowmeter, 24-flow regulating valve, 25-control valve, 31-water drain pipe, 32-ultrasonic flowmeter to be calibrated, 41-water supplementing pipe, 42-liquid level regulating valve, 51-collecting tank, 52-water return pipe and 53-reflux pump.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

In the description of the present application, it is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings, which is for convenience and simplicity of description, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, is not to be considered as limiting.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

Referring to fig. 1 to 4 together, the ultrasonic flowmeter calibration device provided in the present application will now be described. The ultrasonic flowmeter calibration device comprises a pressure stabilizing water tank 11, a water conveying pipe 21 and a plurality of water discharging pipes 31. One end of the water delivery pipe 21 is connected with the pressure stabilizing water tank 11, and the other end of the water delivery pipe 21 is connected with each drain pipe 31; the surge tank 11 supplies a flow of water of a steady pressure into the water delivery pipe 21, and the flow of water is sent to any one of the water discharge pipes 31 through the water delivery pipe 21. The water delivery pipe 21 includes a water delivery main pipe 21a and a plurality of branch pipes 21b, one end of the water delivery main pipe 21a is connected to the pressure stabilizing water tank 11, each branch pipe 21b is connected to each water discharge pipe 31, and each branch pipe 21b is connected to the water delivery main pipe 21 a. The water delivery main pipe 21a is provided with a standard flowmeter 23 and a flow regulating valve 24, the standard flowmeter 23 is used for detecting the flow in the water delivery main pipe 21a, and the flow regulating valve 24 is used for regulating the water flow in the water delivery main pipe 21 a. Each branch pipe 21b is provided with a control valve 25, the control valve 25 is used for controlling the on-off of the branch pipe 21b, and each drain pipe 31 can support the ultrasonic flowmeter 32 to be calibrated. The models of the ultrasonic flow meters 32 to be calibrated are the same. The stable water pressure can be provided for the water delivery main pipe 21a by the stable water tank 11, so that stable water flow can be obtained in each water discharge pipe 31; by adopting the drainage pipes 31 with different cross sections, the non-full flow data of the drainage pipes 31 with different cross sections under stable water flow can be obtained, and after curve fitting is carried out on multiple groups of obtained data of the drainage pipes 31 with different cross sections, a reference function between the standard flow and the display value of the ultrasonic flowmeter 32 to be calibrated can be obtained. Because the reference function adopts data obtained by the drainage pipes 31 with different cross sections, the reference function has wider adaptability, namely after the ultrasonic flowmeter to be calibrated of the reference function is used for the drainage pipes with different cross section shapes, although a certain difference exists between the ultrasonic flowmeter and the real flow of the drainage pipe, the display value of the ultrasonic flowmeter can keep consistent with the real flow rule of the drainage pipes with various cross sections. The drain pipes 31 with different cross sections are adopted for calibration to obtain the reference function, so that the difference of the reference function relative to the drain pipes 31 with different cross sections can be reduced, when the coefficient of the reference function is calibrated, the error caused by the difference of the reference function can be reduced, the calibration error is reduced, and the detection accuracy of the calibrated ultrasonic flowmeter 32 is improved.

For example, when curve fitting is performed on three groups of data acquired in one drain pipe 31, different functional relationships can be obtained by using an exponential relationship, a linear relationship, a logarithmic relationship, a polynomial relationship, or the like, wherein a trinomial function satisfying the three groups of data can be necessarily obtained; when exactly three sets of data are linear, there are at least two functions that can fit the three sets of data perfectly. However, when six sets of data obtained by two different water discharge pipes 31 are fitted, it is assumed that the standard flow values in the three sets of data of the two water discharge pipes 31 are respectively equal, but there may be a large difference between the corresponding display values in the two sets of data, at this time, the function obtained by curve fitting the three sets of data of any water discharge pipe 31 is greatly different from the function obtained by curve fitting the other water discharge pipe 31, so that when the reference function obtained by curve fitting the data of the first water discharge pipe 31 is used by the ultrasonic flow meter 32 to be calibrated and installed on the second water discharge pipe 31, the error is extremely large, and even the ultrasonic flow meter cannot be calibrated by the data obtained by the second water discharge pipe, so as to reduce the error. The main factor contributing to this difference is the difference in the cross-sectional shape of the drain pipe. Although the correlation coefficient of the function obtained by curve fitting using six sets of data is smaller than that obtained by curve fitting of three sets of data obtained at any drain pipe 31, the correlation coefficient of the function with respect to the six sets of data is larger than that of the function obtained by curve fitting of three sets of data on any drain pipe 31 with respect to the six sets of data, that is, the data of various drain pipes 31 can be closer to the obtained function. The function may be used as a reference function of the ultrasonic flow meter 32 to be calibrated, and when the ultrasonic flow meter 32 to be calibrated is installed on a specific drain pipe 31, the ultrasonic flow meter 32 may be further calibrated through data obtained from the drain pipe 31, and since the obtained data is closer to a curve of the reference function, it is convenient to calibrate the reference function to a calibration function suitable for the drain pipe 31. Therefore, the problem of difference of reference equations obtained by using the drainage pipe with the single-shaped cross section in the existing calibration method is solved.

Further, the drain pipe 31 includes a trapezoidal drain pipe 31 having a trapezoidal cross section. The trapezoid is the cross section shape commonly used for the pipe duct, and the drain pipe 31 with the trapezoid cross section can correspond to the pipe duct with the common trapezoid cross section, so that the calibration error of the ultrasonic flowmeter installed on the pipe duct with the trapezoid cross section is reduced.

Further, the drain pipe 31 comprises a circular drain pipe 31 with a circular cross section, the circular pipe is a cross section shape commonly used for a pipe duct, and the drain pipe 31 with the circular cross section can correspond to the common pipe duct with the circular cross section, so that the calibration error of the ultrasonic flowmeter installed on the pipe duct with the circular cross section is reduced.

Further, the drain pipe 31 includes a trapezoidal drain pipe 31 having a trapezoidal cross section and a circular drain pipe 31 having a circular cross section. Therefore, the calibration of the pipe duct with the common cross section shape can be met, and the calibration cross section of the ultrasonic flowmeter on the pipe duct with the cross section shapes similar to those of the two pipe ducts can be also suitable. For example, the bottom is horizontal, and the two sides are parabolic or arc-shaped.

Furthermore, a liquid level sensor is arranged at the bottom of the pressure stabilizing water tank 11, and the liquid level sensor is arranged to facilitate control of the liquid level in the pressure stabilizing water tank 11, so that the fluctuation of water flow pressure and flow caused by the impact of the fluctuation of the liquid level in the pressure stabilizing water tank 11 on the water flow in the water main pipe 21a is avoided.

Furthermore, a water supply pipe 41 is connected to the pressure stabilizing water tank 11, and the water supply pipe 41 can supply water to the pressure stabilizing water tank 11 to control the pressure at the connection position of the pressure stabilizing water tank 11 and the water delivery pipe 21 to be stable. The water supply pipe 41 is provided with a liquid level regulating valve 42 for regulating the water quantity injected into the pressure stabilizing water tank 11 by the water supply pipe 41. Therefore, the water pressure in the calibration process can be controlled, so that the ultrasonic flowmeter to be measured and the standard flowmeter 23 can be under the same pressure, and the phenomenon that the original flow value of the ultrasonic flowmeter 32 to be calibrated and the standard flow value detected by the standard flowmeter 23 are interfered by pressure fluctuation to influence the accuracy of a calibration result is avoided. On the other hand, the water supply pipe 41 can supply water to the interior of the pressure-stabilizing water tank 11 when there is no water or there is no water.

Further, the ultrasonic flowmeter calibration device further comprises a water return assembly, and the water return assembly is used for conveying the drained water of each drain pipe 31 to the pressure stabilizing water tank 11. Therefore, the water in the ultrasonic flowmeter calibration device can be recycled. Moreover, when the water return assembly is matched with the water supply pipe 41, the size of the water supply pipe can be reduced, so that the water supply amount of the pressure stabilizing water tank 11 can be accurately controlled, and the fine adjustment of the liquid level in the pressure stabilizing water tank 11 is realized; the water flow in the whole ultrasonic flowmeter calibration device is stable through the water return assembly.

Further, referring to fig. 2, fig. 3 and fig. 4 together, as an embodiment of the calibration apparatus for an ultrasonic flow meter provided in the present application, the water return component includes a collecting tank 51, a water return pipe 52 and a return pump 53. The collecting tank 51 is used for collecting the water discharged from each of the water discharge pipes 31, the return pipe 52 connects the collecting tank 51 with the surge tank 11, and the return pump 53 is installed on the return pipe 52 for delivering the water in the collecting tank 51 to the surge tank 11. When the collecting tank 51 collects the drainage in the drainage pipe 31, the pulse in the water flow can be eliminated, and the pulse in the water flow is prevented from impacting the water flow in the water return pipe 52 to influence the stability in the pressure stabilizing water tank 11.

Specifically, the pressure-stabilizing water tank 11 may be a sealed tank, a compressed air pipe and an exhaust pipe are connected to the top of the sealed tank, and compressed air is introduced to the top of the pressure-stabilizing water tank 11; a pressure sensor is arranged at the top of the pressure-stabilizing water tank 11, and compressed air is introduced into the top of the pressure-stabilizing water tank 11 according to the pressure value of the pressure-stabilizing water tank 11 or the compressed air is released, so that the water outlet pressure of the pressure-stabilizing water tank 11 is kept stable; the liquid level in the pressure-stabilizing water tank 11 is maintained stable by the reflux pump 53 and the liquid level regulating valve 42 of the water replenishing pipe 41. On one hand, the compressed air can eliminate the impact on the internal water pressure when the water flow enters the stable-pressure water tank 11, and reduce the internal water pressure and the fluctuation of the water flow; on the other hand, the pressure of the pressure stabilizing water tank 11 can be adjusted according to the requirement by adopting compressed air, which is beneficial to reducing the volume of the pressure stabilizing water tank 11.

Of course, the surge tank 11 may be an open-topped overflow tank, and the liquid level and pressure inside the surge tank 11 are kept stable by overflow.

Specifically, the reflux pump 53 is a variable frequency pump, and the flow rate of reflux water can be adjusted by using the variable frequency pump, so that the water flow can be stably circulated between the reflux tank and the pressure stabilizing water tank 11.

Preferably, each drain pipe 31 is made of concrete. Therefore, the drain pipe 31 and the actually installed pipe duct can be ensured to be basically consistent in material, and errors caused by the material of the pipe duct after the ultrasonic flowmeter 32 to be calibrated is installed are avoided.

The application further provides an ultrasonic flowmeter calibration method, the ultrasonic flowmeter calibration device described in any of the above embodiments is used for calibrating an ultrasonic flowmeter to be calibrated, and the calibration method includes the following steps:

s1, mounting ultrasonic flow meters to be calibrated on the drainage pipes;

s2, controlling the water flow in the water delivery main pipe to flow out through the water discharge pipes in sequence, and controlling the water flow of the water delivery main pipe when the water flow flows through the water discharge pipes, so that a plurality of groups of flow rate values (Q) of the water discharge pipes can be obtained_{raw_value}，Q_{stan._value}) Wherein Q is_{raw_value}For the flow value (detection signal value), Q, of the ultrasonic flowmeter to be calibrated_{stan._value}The standard flow value is corresponding to a standard flow meter on the water delivery main pipe;

s3, according to the multiple groups of Q in the step S2_{raw_value}And Q_{stan._value}The value of the reference function f is subjected to curve fitting to obtain a reference function f of the ultrasonic flowmeter to be calibrated_base(Q_{raw_value}，Q_{stan._value})；

S4, converting the reference function f_base(Q_{raw_value}，Q_{stan._value}) Implanting each ultrasonic flowmeter to be calibrated.

By using more than oneThe drainage pipes 31 with different cross sections can obtain a plurality of groups of flow values Q of the ultrasonic flowmeter 32 to be calibrated of the drainage pipes 31 with different cross sections_{raw_value}And a standard flow rate value Q corresponding thereto_{stan._value}. When curve fitting is carried out, the obtained reference function can be suitable for measuring the flow of the drainage pipes 31 with the cross sections of more different shapes. The benchmark function can be implanted into the ultrasonic flowmeter during the production of the ultrasonic flowmeter, so that when the ultrasonic flowmeter is installed in a specific application pipeline, the benchmark function f in the ultrasonic flowmeter can be further calibrated according to the flow data on the pipeline and the detection value of the ultrasonic flowmeter_base(Q_{raw_value}，Q_{stan._value}) And further reduces the error of the ultrasonic flowmeter. The calibration method of the ultrasonic flowmeter adopts the reference equation derived from curve fitting of different drain pipes, so that the ultrasonic flowmeter is prevented from being influenced by the difference between the depth and the flow rate of a single drain pipe, the error of the reference equation is too large when the reference equation is applied to drain pipes with cross sections of other shapes, and the error caused by the reference function cannot be corrected even if the actual flow is calibrated by applying the pipe duct.

Alternatively, in step S3, it is preferable to adopt

Obtaining a reference function f of the ultrasonic flowmeter to be calibrated_base(Q_{raw_value}，Q_{stan._value}) Coefficient k of₀、k₁And k₂. Of course, in other embodiments of the present application, the fitting may be performed in other manners, such as using the formula Q_{stan._value_i}＝k₀+k₁ln(Q_{raw_value_i})+k₂ln²(Q_{raw_value_i}) To solve for each coefficient.

Further, after step S4, the method further includes:

S7, according to each group Q in the step S6_{raw_value_i}And Q_{stan._value_i}To the reference function f_base(Q_{raw_value}，Q_{stan._value}) To obtain a calibration function f of the ultrasonic flow meter to be calibrated_cal.(Q_{raw_value}，Q_{stan._value})；

S8, calibrating the reference function f in the ultrasonic flowmeter to be calibrated_base(Q_{raw_value}，Q_{stan._value}) Correction to a calibration function f_cal.(Q_{raw_value}，Q_{stan._value})。

In the above steps S5-S8, the actual installation pipeline of the ultrasonic flow meter to be calibrated is simulated by selecting a drain pipe with a cross section similar to the cross section of the application pipeline of the ultrasonic flow meter to be calibrated and installing the ultrasonic flow meter to be calibrated on the drain pipe. By means of sets (Q) obtained on the drain_{raw_value_i}，Q_{stan._value_i}) To the reference function f implanted in the ultrasonic flow meter in step S4_base(Q_{raw_value}，Q_{stan._value}) The coefficient of the ultrasonic flowmeter to be calibrated is further calibrated, and therefore the error between the display value and the real value of the ultrasonic flowmeter to be calibrated is reduced. Wherein Q is_{raw_value_i}Representing the flow value, Q, of the ultrasonic flowmeter to be calibrated on the selected drain pipe_{stan._value_i}And indicating the standard flow value corresponding to the standard flowmeter, wherein the corresponding is the standard flow value of the standard flowmeter at the same time (or in the same time) and the flow value of the ultrasonic flowmeter to be calibrated on the selected drainage pipe. After the calibration of the coefficient of the reference function is completed, the ultrasonic flowmeter to be calibratedAnd correcting the reference function into the calibration function, namely installing the ultrasonic flowmeter to be calibrated on an application pipeline and detecting the flow in the application pipeline. Therefore, the situation that accurate flow values in the non-full pipe and pipe conduits cannot be obtained after the ultrasonic flowmeter to be calibrated is installed due to the fact that the flow of the non-full pipe and pipe conduits is not easy to measure can be avoided, and the ultrasonic flowmeter after being installed cannot be calibrated.

Alternatively, in step S8, the reference function set at the time of manufacturing the flowmeter may be calibrated to the calibration function in the actual meter head or the upper computer when the flowmeter is actually used. Actual meter head or upper computer display flow f_cal.(Q_{raw_value}) May be a flow value f calculated from a reference function_base(Q_{raw_value}) In a linear relationship, e.g. f_cal.(Q_{raw_value})＝γ*f_base(Q_{raw_value}) And the like. Of course, in other embodiments of the present application, other linear equations may be used to calibrate the reference function, such as f_cal.(Q_{raw_value})＝γ* f_base(μQ_{raw_value}+ τ). Wherein a signal value Q is detected in the flow meter_{raw_value}， f_base(Q_{raw_value}) Is formed by f_base(Q_{raw_value}，Q_{stan._value}) Q calculated by function_{stan._value}Value (either as a calculated value inside the gauge head or as a display value of the gauge head or the host computer), f_cal.(Q_{raw_value}) Is formed by f_cal.(Q_{raw_value}，Q_{stan._value}) Q calculated by function_{stan._value}Values (i.e., values displayed on the head or upper computer), γ, μ, and τ are correction coefficients.

On the other hand, in the production process of the ultrasonic flow meter, the difference between the electronic components and the ultrasonic transducers of different ultrasonic flow meters can also make the meter coefficient ξ of each ultrasonic flow meter not identical. However, in steps S1-S4, by installing a plurality of ultrasonic flow meters to be calibrated on a plurality of pipes with different cross sections, the influence of a single ultrasonic flow meter on calibration data can be reduced, and then the meter coefficients tend to be averaged through curve fitting between a plurality of sets of data, namely:

wherein: xi_iThe meter coefficient of the ultrasonic flowmeter to be installed on each drain pipe is represented, N represents the number of detections (i.e., the sum of the number of measurements of the ultrasonic flowmeters on all the drain pipes), and ξ is the averaged meter coefficient. In steps S5-S8, a calibration function close to the real flow is obtained by calibrating a reference function of the ultrasonic flowmeter to be calibrated, and compensation of the coefficient in the reference function from the average value xi to xi of the coefficient of the ultrasonic flowmeter to be calibrated is realized by compensating the coefficient in the reference function_i. Although for a single ultrasonic flowmeter, twice calibration is adopted (a reference equation is obtained once, and coefficients of the reference equation are calibrated once), the defects that a reference function is directly set and the reference function coefficients are calibrated by using application of pipe and canal data, which causes overlarge deviation of the reference function and incapability of fitting are overcome through calibrating the coefficients of the reference equation.

For drains of known cross-section and material, the water cross-sectional area a is related only to the water depth h, and the water flow rate Q is related only to the flow velocity v (average velocity) and the water depth h (i.e. Q v a), i.e. the instantaneous water flow rate in each drain: q_iF (v, h), wherein the flow velocity v is constant when the water depth h is stable;

and (3) accumulating flow:

wherein, Δ t_iDenotes a period of time, Q_iRepresents the period of time Δ t_iMean water flow (when Δ t)_iVery short, the corresponding Q can be considered_iI.e., instantaneous flow).

Step S2 further includes: controlling the water flow in the water delivery main pipe, and adjusting the water pressure in the pressure stabilizing water tank to stabilize the water pressure in the pressure stabilizing water tank; obtaining the pressure and flow of the water flow in the drain pipe after the pressure and flow are stableFlow value Q of ultrasonic flowmeter to be calibrated_{raw_value}And a standard flow value Q corresponding to a standard flow meter on the water delivery main pipe_{stan._value}. And the stability and reliability of numerical values can be ensured by controlling the stability of the water flow pressure and flow and then acquiring data. Of course, the same method can be adopted in step S6 to ensure the stability and reliability of the acquired data.

When the water flow in the drain pipe is regulated to be stable (fluctuated in a relatively small amplitude), the water flow can pass through a period of time

The accumulated flow q in the time period is used for calculating the average water flow in the time period so as to reduce the error caused by water flow fluctuation or ultrasonic flowmeter fluctuation. Namely, the flow value Q of the ultrasonic flowmeter to be calibrated is obtained_{raw_value_i}(or Q)_{raw_value}) And a standard flow rate value Q_{stan._value_i}(or Q)_{stan._value}) And meanwhile, the average water flow value of the ultrasonic flowmeter to be calibrated in a period of stable time and the average water flow value of the standard flowmeter in a period of time are adopted, so that the influence of instantaneous fluctuation errors on the calibration of the reference function can be reduced.

Step S2 further includes: the obtained flow value Q of the ultrasonic flowmeter to be calibrated_{raw_value}For the cumulative flow q of the ultrasonic flowmeter to be calibrated in the time delta t_raw.Calculated average water flow value, obtained standard flow value Q_{stan._value}Is the cumulative flow q of a standard flowmeter in time delta t_stanCalculated average water flow value. Namely, Q_{raw_value}＝q_raw./Δt，Q_{stan._value}＝q_stan.A,/Δ t, wherein q_raw.Represents the cumulative flow of the ultrasonic flowmeter to be calibrated in time delta t, q_stan.Representing the corresponding cumulative flow rate of the standard flow meter over time at. The average water flow value is adopted for curve fitting, so that the influence of instantaneous fluctuation of the flowmeter to be calibrated, the standard flowmeter and water flow on the accuracy of the reference function can be reduced.

Step S6 further includes: acquired waiting markDetermining the flow rate Q of an ultrasonic flowmeter_{raw_value_i}For the cumulative flow q of the ultrasonic flowmeter to be calibrated in the time delta t_{raw._i}Calculated average water flow value, obtained standard flow value Q_{stan._value_i}Is the cumulative flow q of a standard flowmeter in time delta t_{stan_i}Calculated average water flow value. Namely, Q_{raw_value_i}＝q_{raw._i}/Δt，Q_{stan._value_i}＝q_{stan._i}A,/Δ t, wherein q_{raw._i}Represents the cumulative flow of the ultrasonic flowmeter to be calibrated in time delta t, q_{stan._i}Representing the corresponding cumulative flow rate of the standard flow meter over time at. The average water flow value is adopted for curve fitting, so that the influence of instantaneous fluctuation of the flowmeter to be calibrated, the standard flowmeter and water flow on the accuracy of the reference function can be reduced.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An ultrasonic flowmeter calibration device which characterized in that: the water delivery pipe comprises a pressure stabilizing water tank, a water delivery pipe and a plurality of drainage pipes, wherein the pressure stabilizing water tank is used for providing stable water outlet pressure, one end of the water delivery pipe is connected with the pressure stabilizing water tank, the drainage pipes are used for supporting an ultrasonic flowmeter to be calibrated, the cross section shapes of the drainage pipes are different, the water delivery pipe comprises a water delivery main pipe and a plurality of branch pipes, one end of each branch pipe is connected with the pressure stabilizing water tank, the branch pipes are respectively connected with the water delivery main pipe, the water delivery main pipe is provided with a standard flowmeter used for detecting the water flow in the water delivery main pipe and a flow regulating valve used for regulating the water flow in the water delivery main pipe, and each branch pipe is respectively provided with a control valve used for controlling.

2. An ultrasonic flow meter calibration apparatus as claimed in claim 1, wherein: and a liquid level sensor is arranged at the bottom of the pressure stabilizing water tank.

3. An ultrasonic flow meter calibration apparatus as claimed in claim 1, wherein: and the pressure stabilizing water tank is connected with a water replenishing pipe, and the water replenishing pipe is provided with a liquid level regulating valve.

4. An ultrasonic flow meter calibration apparatus as claimed in claim 1, wherein: the calibration device of the ultrasonic flowmeter further comprises a water return assembly used for conveying the drainage water of each drainage pipe to the pressure stabilizing water tank.

5. An ultrasonic flow meter calibration apparatus according to claim 4, wherein: the water return component comprises a collecting tank used for collecting water drained by each drain pipe, a water return pipe connected with the collecting tank and the pressure stabilizing water tank, and a reflux pump installed on the water return pipe.

6. An ultrasonic flow meter calibration apparatus as claimed in claim 5, wherein: the reflux pump is a variable frequency pump.