Showing papers on "Ultrasonic flow meter published in 2014"

System for and method of monitoring flow through mass flow controllers in real time

Abstract: A mass flow controller comprises: a first flow meter constructed and arranged to measured flow rate of mass through the mass flow controller; a second flow meter constructed and arranged to measure flow rate of mass through the mass flow controller; a control valve constructed and arranged so as to control the flow rate of mass through the mass flow controller in response to a control signal generated as a function of the flow rate as measured by one of the flow meters; and a system controller constructed and arranged to generate the control signal, and to provide an indication when a difference between the flow rate of mass as measured by the first flow meter and the flow rate of mass as measured by the second flow meter exceeds a threshold.

ANN Based Data Integration for Multi-Path Ultrasonic Flowmeter

Abstract: This paper presents an artificial neural network (ANN) based data integration method for a four-path ultrasonic flowmeter to improve its performance under complex flow profiles. Computational fluid dynamics (CFD) has been used to obtain the flow profiles inside a single elbow and an out-plane double-elbow pipeline, respectively, to extract the flow velocities on different individual sound paths and the corresponding mean flow velocities on the cross-sections located at 5 and 10 times pipe diameter downstream the elbow. The results from the CFD simulation for Reynolds number in the range from 3.25×103 to 3.25×105 were used to construct the data set. A three-layer ANN was designed, in which the flow velocities on individual sound paths and the cross-sectional mean flow velocity are taken as the input and output, respectively. Part of the data set is used to train the ANN. The other part of the data set is used to test the feasibility of the ANN. It was found that the error of the estimated cross-sectional mean flow velocity based on the ANN is within ±0.3% without the requirement of any flow conditioner for Reynolds number in the range from 3.25×103 to 3.25×105, which is significantly better than the results from the traditional weighted integration method. The proposed ANN based data integration method is of extending the limitation of straight pipe length for the installation of multi-path ultrasonic flowmeter and promoting its practical applications under complex flow profiles.

CFD Aided Investigation of Multipath Ultrasonic Gas Flow Meter Performance Under Complex Flow Profile

Abstract: This paper presents a systematic investigation of the influence of complex flow profiles on the performance of multipath ultrasonic gas flow meter by using computational fluid dynamics (CFDs) simulation. To guarantee the overall agreement between the CFD predictions and the measurements, the meshing approaches, generation of boundary layers, turbulence models, and wall treatment methods for CFD simulation are elaborated carefully. The performances of a multipath ultrasonic gas flow meter under complex flow profiles, regarding to an out-plane double-elbow with a half-moon block and an out-plane double-elbow with a half-moon block equipped with a Spearman conditioner, are investigated. The simulation results demonstrate that for complex flows with strong asymmetric and swirling velocity profiles inside an out-plane double-elbow pipeline with a half-moon block, a four-path ultrasonic flow meter located at 20-D right after the second elbow together with a Spearman conditioner installed 16-D upstream the meter is of providing a flow velocity estimation that the error is within ±0.5%, while the Reynolds number ranges from 3.25×103 to 3.25×105. The effect of sound path orientation on the performance of flow meter is also discussed.

Support Vector Regression-Based Data Integration Method for Multipath Ultrasonic Flowmeter

Abstract: This paper presents a support vector regression (SVR)-based data integration method for a 4-path ultrasonic flowmeter, which is able to estimate accurately the mean cross-sectional flow velocity under complex flow profiles. While installed in the pipeline with complex configurations, such as single-elbow or out-plane double-elbow, the performance of multipath ultrasonic flowmeter will degenerate due to the strong nonlinear relationships between the flow velocities on different individual sound paths and the mean flow velocity on the cross section, particularly when the straight pipe length is not guaranteed. The presented SVR-based method is of an excellent nonlinear mapping and generalization ability. The cases while the Reynolds number in the range of 3.25 × 10 3 - 3.25 × 10 5 were simulated using computational fluid dynamics and the flow profiles located on the cross sections of 5 and 10 times pipe diameter downstream a single elbow and an out-plane doubleelbow were extracted to construct the data set for SVR training and test. It is found that the error of the estimated crosssectional mean flow velocity obtained by the SVR-based data integration method is within ±0.5% without the requirement of a flow conditioner, which is significantly better than the results from the traditional integration method with constant weights. The presented SVR-based data integration method is helpful to extend the limitation of straight pipe length for the installation of multipath ultrasonic flowmeter, which is attractive for the practical applications of multipath ultrasonic flowmeter.

Flow meter with unbroken liner

Abstract: The present invention relates to an ultrasonic flow meter (1) with an unbroken liner (6) inside the flow tube. The flow tube (2) has at least one through-going opening (5) in the wall. The unbroken liner (6) is provided in a water-tight material and arranged in the flow tube to cover the entire inner surface of the flow tube. The piezoelectric transducers (11, 12) are arranged at an outside of the liner (6) in the at least one through-going opening (5) in the wall of the flow tube(2), so that ultrasonic signals are transmitted through the liner wall to enter the flow tube(2).The liner(6)is provided in a polymer selected from the group consisting of polysulphones, polysulphides and polyaryletherketones.A flow meter (1) is thereby provided which eliminates any need for sealing surfaces in relation to the ultrasonic transducers and which can sustain prolonged use in hot liquid.

Phase controlled variable angle ultrasonic flow meter

Abstract: An ultrasonic flowmeter includes a conduit for receiving a flow of a fluid and a flexible printed circuit board (FPC) including: a pair of ultrasonic transducers, wherein each transducer comprises a piezoelectric element divided into a plurality of segment electrodes and the FPC is bonded around the conduit; and a control circuit configured to sequentially activate the segment electrodes using a pulse train to cause at least one of the piezoelectric elements to emit a sonic signal. A delay time between activation of each successive segment electrode controls a phase velocity and an angle of emission of the corresponding sonic signal.

Ultrasonic flow measurement with high resolution

Abstract: The ultrasonic flowmeter which is described in this paper, measures the transit of time of an ultrasonic pulse. This device consists of two ultrasonic transducers and a high resolution time interval measurement module. An ultrasonic transducer emits a characteristic wave packet (transmit mode). When the transducer is in receive mode, a characteristic wave packet is formed and it is connected to the time interval measurement module inputs. The time interval measurement module allows registration of transit time differences of a few pulses in the packet. In practice, during a single measuring cycle a few time-stamps are registered. Moreover, the measurement process is also synchronous and, by applying the statistics, the time interval measurement uncertainty improves even in a single measurement. In this article, besides a detailed discussion on the principle of operation of the ultrasonic flowmeter implemented in the FPGA structure, also the test results are presented and discussed.

Studies on the transducers of clamp-on transit-time ultrasonic flow meter

Abstract: The clamp-on transit-time ultrasonic flow meters are widely applied for the advantage of noninvasive measurement and convenient deployment. Its key point lies on measuring of the time difference between the upstream and downstream. While high quality of the transducer transmitting/receiving ultrasonic signals is the premise of measuring time difference accurately. This paper studies on the main factors contributing to the uncertainty of the transducer's output signal and focuses on the transducer's frequency, incident angle and the separate distance. The selection principle of transducer's frequency is presented by the analysis of the ultrasonic attention characteristics in the liquid. The incident angle range and precise installation distance of the transducers are calculated and analyzed by Snell's law. Experiments are also carried out with the 1MHz transducers clamped on the aluminium pipe of 20mm outer diameter. The results show that the accurate calculation separate distance 18.16mm is effective to guarantee the output of high quality ultrasonic wave. If the axial installation error reaches more than 3mm, the one beam of ultrasonic signal cannot be guaranteed.

Ultrasonic flow metering with laminar to turbulent transition flow control

Abstract: Apparatus and method for ultrasonic flow metering of viscous fluids. In one embodiment, an ultrasonic flow metering system includes an ultrasonic flow meter, a flow conditioner, and a reducer. The ultrasonic flow meter includes a pair of ultrasonic transducers arranged to exchange ultrasonic signals through a fluid stream flowing between the transducers. The flow conditioner is disposed upstream of the ultrasonic flow meter. The reducer is disposed between the flow conditioner and the ultrasonic flow meter to reduce the cross sectional area of the fluid stream flowing from the flow conditioner to the ultrasonic flow meter.

Flow measuring method of ultrasonic flow meter

Abstract: The invention relates to a flow measuring method of an ultrasonic flow meter. The method comprises the following steps: arranging a pair of ultrasonic sensors on the upper stream and lower stream of a gas flow channel of the ultrasonic flow meter for transmitting and receiving ultrasonic pulse signals, providing a driving voltage for driving transmitting parts of the ultrasonic sensors by using a driving module, measuring time when a timing module starts timing after ultrasonic pulse signals are transmitted by the ultrasonic sensors, stopping timing when an Nth zero crossing point is detected after first Umaxi which is larger than a pulse signal voltage threshold U0, and calculating a time difference between the start of timing and the stop of timing; measuring once downstream and upstream respectively, and calculating the flow of fluid on a measurement timing module. Through reasonable setting of the pulse signal voltage threshold U0 and the noise removing function of a signal conditioning module, the measuring error of small flow in a gas flow channel of the ultrasonic flow meter and the interference of noise on the accuracy of a measuring result are reduced to the largest extent, and higher measuring accuracy is achieved.

System for and method of providing pressure insensitive self verifying mass flow controller

Abstract: A mass flow controller comprises: a pressure-based flow meter, a thermal-based flow meter, a control valve, and a system controller. The pressure-based flow meter and thermal-based flow meter each measure flow rate of mass through the mass flow controller. The control valve controls the flow rate in response to a control signal generated as a function of the flow rate as measured by thermal-based flow meter when the measured flow rate is relatively low, and as a function of the flow rate as measured by the pressure-based flow meter when the flow rate is relatively high. A comparison of the flow measurements of the two flow meters can be used to (a) sense pressure disturbances at low flow rates, and (b) sense when the thermal-based flow meter is out of calibration so that a zero offset signal can be applied to the thermal-based flow meter.

Temperature influence eliminating method for time difference ultrasonic flowmeter

Abstract: The invention discloses a temperature influence eliminating method for a time difference ultrasonic flowmeter. The temperature influence eliminating method comprises the following steps: measuring the propagation speeds of ultrasonic waves in a fluid and the fluid kinematic viscosity, at a plurality of temperature points; carrying out segmentation fitting to obtain a temperature modifier formula v=f(T) of the propagation speed of the ultrasonic waves in the fluid and a temperature modifier formula of the fluid kinematic viscosity, shown in the specification; respectively calculating the actual sound velocity of the sound channel where a probe is positioned and the actual kinematic viscosity of the fluid according to the fluid temperature during measuring, sound velocity temperature modifier formula, and the temperature modifier formula of the fluid kinematic viscosity; calculating the fluid velocity of the sound channel where the probe is positioned according to the actual sound velocity and the time difference obtained by measurement; judging in which state the measured fluid is positioned, a laminar flow state or turbulent flow state, according to the fluid velocity of the sound channel where the probe is positioned, the measured size of pipe diameter and the fluid kinematic viscosity after the influence from temperature is eliminated; calculating the flow by using a corresponding laminar flow speed-flow modifier formula or turbulent flow speed-flow modifier formula, according to the flow state of the measured flow and the arrangement position of the sound channel.

Application of Womersley Model to Reconstruct Pulsatile Flow From Doppler Ultrasound Measurements

Abstract: A Womersley model-based assessment of pulsatile rigid-tube flow is presented. Multigate Doppler ultrasound was used to measure axial velocities at many radial locations along a single interrogation beam going through the center of a stiff tube. However, a large impediment to Doppler ultrasound diagnostics and resolution close to the wall is considerable noise due to the presence of the wall-fluid interface as well as many other effects, such as spectral broadening, coherent scattering, time resolution, and Doppler angle uncertainty. Thus, our confidence in measured signals is questionable, especially in the wall vicinity where the important oscillatory shear stresses occur. In order to alleviate known biases and shortcomings of the pulsed Doppler ultrasound measurements we have applied Womersley's laminar axisymmetric rigid-tube approximation to reconstruct velocity profiles over the entire flow domain and specifically close to wall, enabling unambiguous determination of the shear stresses. We employ harmonic analysis of the measured velocity profiles at all or selected trusted tube radial locations over one or more periods. Each of estimated Fourier coefficients has a unique counterpart in the respective pressure gradient component. From ensemble-averaged cross-sectional pressure gradient components we compute velocity profiles, volume flow rate, wall shear stress, and other flow parameters. Estimation of the pressure gradients from spatially resolved pulsed Doppler ultrasound velocity measurements is an added benefit of our reconstruction method. Multigate pulsed Doppler ultrasound scanners offer powerful capabilities to noninvasively and nonintrusively measure velocity profiles for hemodynamic and other fluid flow applications. This flow reconstruction method can also be tailored for use with other flow diagnostic modalities, such as magnetic resonance imaging (MRI) and a wide class of optical methods.

Ultrasonic flow meter device

Abstract: An ultrasonic flow meter device comprises a fluid passage forming section including a measurement fluid passage, and an opening facing a bottom surface of the measurement fluid passage; a pair of ultrasonic transducers which transmit and receive an ultrasonic wave via the opening; a partition plate which partitions the measurement fluid passage; and an identification section provided on an end surface of the partition plate and used to identify an obverse surface and a reverse surface of the partition plate.

Easy-setup clamp-on ultrasonic flowmeter

Abstract: A clamp-on ultrasonic flowmeter is the only flowmeter that can be installed on existing pipelines without draining and plumbing. In conventional clamp-on ultrasonic flowmeters, the relative position of transducers depends heavily on the properties of the pipe on which the transducers are mounted. It takes a high engineering cost at the time of installation because a specialized engineer is needed to align the position of the transducers and input pipe properties. In this paper, to solve this problem, we propose a new type of clamp-on ultrasonic flowmeter with opposing transducers configuration to reduce engineering cost during the installation by eliminating the location alignment of transducers, and show flow velocity measurement results at various pipe diameters with ±6% accuracy. Additionally, we show the measurement results of the pipe diameter from the received signal and suggest the possibility for the automatic measurement of pipe properties.

Transverse spectral velocity estimation

Abstract: A transverse oscillation (TO)-based method for calculating the velocity spectrum for fully transverse flow is described. Current methods yield the mean velocity at one position, whereas the new method reveals the transverse velocity spectrum as a function of time at one spatial location. A convex array probe is used along with two different estimators based on the correlation of the received signal. They can estimate the velocity spectrum as a function of time as for ordinary spectrograms, but they also work at a beam-to-flow angle of 90°. The approach is validated using simulations of pulsatile flow using the Womersly-Evans flow model. The relative bias of the mean estimated frequency is 13.6% and the mean relative standard deviation is 14.3% at 90°, where a traditional estimator yields zero velocity. Measurements have been conducted with an experimental scanner and a convex array transducer. A pump generated artificial femoral and carotid artery flow in the phantom. The estimated spectra degrade when the angle is different from 90°, but are usable down to 60° to 70°. Below this angle the traditional spectrum is best and should be used. The conventional approach can automatically be corrected for angles from 0° to 70° to give fully quantitative velocity spectra without operator intervention.

Ultrasonic flow meter

Abstract: An ultrasonic flow meter is equipped with a housing through which a liquid flows, and a pair of detection units disposed on opposite ends of the housing and including acoustic wave transmitting and receiving units capable of transmitting and receiving acoustic wave signals Vibration generating mechanisms having vibration generating bodies arranged perpendicularly to the detection units are disposed on an outer circumferential side of the housing In addition, when the flow rate of the liquid that flows through the housing is measured, the vibration generating bodies are energized and made to vibrate, such that gas bubbles, which adhere to cover members in contact with the liquid and that cover the acoustic wave transmitting and receiving units, are removed by the vibrations

Flow Measurement Model of Ultrasonic Flowmeter for Gas-Liquid Two-Phase Stratified and Annular Flows:

Abstract: An error correction model for ultrasonic gas flowmeter was proposed to explore the potential of an ultrasonic flowmeter for metering gas-liquid stratified and annular flows. The gas and liquid mass...

Adaptive multi-lag for synthetic aperture vector flow imaging

Abstract: The range of detectable velocities in ultrasound flow imaging is linked to the user selection of pulse repetition frequency. Whenever a region with large differences in velocity magnitude is visualized, a trade-off has to be made. This work suggests an adaptive spatio-temporaly independent, multi-lag method, which is performed in synthetic aperture vector flow data. Measurements are made on laminar and pulsatile, transverse flow profiles. A 7 MHz linear array is connected to the SARUS research, and acquisitions are made on a vessel phantom with recirculating blood mimicking fluid driven by a software controlled pump. A multi-lag velocity estimation is performed, and a lag is adaptively selected for every estimation point. Results from the constant flow compared to a true parabolic profile show an improvement in relative bias from 76.99% to 0.91% and standard deviation from 13.60% to 1.83% for the low velocity flow of 0.04 m/s; and relative bias from −2.23% to −1.87% and standard deviation from 3.71% to 2.29% for the high velocity flow of 0.4 m/s.

Fluid flow measuring apparatus

Abstract: The invention discloses a fluid flow measuring apparatus and belongs to the technical field of fluid measurement. The fluid flow measuring apparatus comprises a Venturi flowmeter throttling element (1) and an ultrasonic flowmeter sensor (2), wherein the ultrasonic flowmeter sensor (2) is arranged on a cylindrical throat (C) of the Venturi flowmeter throttling element (1). The measurement range ratio of the flow measuring apparatus reaches 500-1000 times, precision is within 1%, and the technical problem that an existing flowmeter is low measuring range ratio and low in precision is solved. The fluid flow measuring apparatus is particularly applicable to flow measurement occasions such as community main meters, large-scale enterprise main meters, area metering and city pipe network monitoring with high requirement on the measurement range ratio.

High-speed gas flow calibration system and calibration method based on laboratory multiple pipelines

Abstract: The invention discloses a high-speed gas flow calibration system and a high-speed gas flow calibration method based on laboratory multiple pipelines. The system comprises a gas source generating device, a standard meter region, a to-be-measured meter region and a main controller, and is characterized in that an air compressor and a front gas storage tank form the gas source generating device of the system; three pipelines which are respectively provided with a nozzle flowmeter, a vortex street flowmeter and an ultrasonic flowmeter and are connected in parallel are the standard meter region of the system; a rear gas storage tank and three pipelines which are respectively provided with three meters to be measured and are connected in parallel are the to-be-measured meter region of the system. According to the high-speed gas flow calibration system and the high-speed gas flow calibration method based on the laboratory multiple pipelines, the fluid generation is controlled by adopting an improved process control system, the reliability of the system gas source is improved, a multi-pipeline calibration mode is creatively invented, the applicable capacity of the system is stronger, and the system can well meet various requirements of laboratory gas flow calibration.

Assessment of combined V/Z clamp-on ultrasonic flow metering †

Abstract: Clamp-on ultrasonic flow metering can provide a non-invasive and portable means for flow measurement. However, it indicates flow rates with low measurement accuracy at low flow velocity in pipe flows. Typical accuracy of the clamp-on ultrasonic flow metering amounts as low as ±1% if the flow velocity in a pipe is greater than 0.5 m/s. The accuracy can be increased greater than ±2% if the flow velocity is lowered smaller than 0.5 m/s. Inner pipe diameter can be also an influential factor in flow metering when the exact value of the inner diameter is not known. The inner pipe diameter cannot be found if the pipe is too large to measure or if there are erosions or adhesions on the inner pipe surface due to small particles in the flow. These shortcomings of the clamp-on ultrasonic flow metering can be overcome by combining two transit times along a Z-shaped and a V-shaped ultrasonic path. This technique is termed combined V/Z clamp-on ultrasonic flow metering. With the water flow standard system in KRISS, this combined technique exhibited intermediate performance between the two flow metering techniques along the Z-shaped and the V-shaped ultrasonic paths. Notably, the combined technique showed better performance (expanded uncertainty less than 0.76%, k = 2) than the two flow metering techniques (1.61% and 1.17%, k = 2) in the flow range of (100–400) m3/h with pipe diameter of 250 mm.

Numerical Analysis of Transducer Installation Effect on Ultrasonic Gas Flow Meter

Abstract: As for ultrasonic gas flow meters, special attention should be paid to transducer installation effect as the flow disturbed by transducers will greatly affect the transit time determination and accordingly reduce metering accuracy. This paper presents a numerical method to analyze the disturbed effects based on Computational Fluid Dynamic (CFD), which can give valuable guides for transducer installations. Different pipe configurations covering a wide velocity range are modelled to simulate the actual flow field in different chords for three transducer installations including protrusion, recess and half protrusion. Then, detailed results are presented and the mechanism is analyzed to give suggestions about better transducer installations and a modified weighting factor method to improve the incredible error is also given in this paper.

Accuracy and sources of error for an angle independent volume flow estimator

Abstract: This paper investigates sources of error for a vector velocity volume flow estimator. Quantification of the estimator's accuracy is performed theoretically and investigated in vivo. Womersley's model for pulsatile flow is used to simulate velocity profiles and calculate volume flow errors in cases of elliptical vessels and not placing the transducer at the vessel center. Simulations show, i.e., that volume flow is underestimated with 5 %, when the transducer is placed 15 % from the vessel center. Twenty patients with arteriovenous fistulas for hemodialysis are scanned in a clinical study. A BK Medical UltraView 800 ultrasound scanner with a 9 MHz linear array transducer is used to obtain Vector Flow Imaging sequences of a superficial part of the fistulas. Cross-sectional diameters of each fistula are measured on B-mode images by rotating the scan plane 90 degrees. The major axis of the fistulas was on average 8.6 % larger than the minor axis, so elliptic dimensions should be taken into account in volume flow estimation. The ultrasound beam was on average 1.5 ± 0.8 mm off-axis, corresponding to 28.5 ± 11.3 % of the major semi-axis of a fistula, and this could result in 15 % underestimated volume flow according to the simulation. Volume flow estimates were corrected for the beam being off-axis, but was not able to significantly decrease the error relative to measurements with the reference method.