Showing papers on "Ultrasonic flow meter published in 1987"

Measurement of velocity profile of mercury flow by ultrasound doppler shift method

Abstract: The ultrasound velocity profile monitor has been developed. It utilizes the pulsed echo techniques of ultrasound, and it can measure the velocity profile quasi-instantaneously. Its applicability to...

Ultrasonic flow meter

Abstract: A flowmeter comprises a measuring tube, an ultrasound transducer, an ultrasound waveguide and a seal. The transducer connects outside the measuring tube to waveguide such that ultrasound waves generated by transducer are transferred to waveguide and, conversely, waves received by waveguide are transferred to transducer (2). The waveguide protrudes into the measuring tube.

Ultrasonic apparatus for measuring the flow velocity of a fluid

Abstract: An ultrasonic measuring apparatus is provided for measuring the flow velocity of a fluid in a pipe. The apparatus includes a pair of sensors which are mounted on a pipe, and which alternately transmit and receive ultrasonic waves. When the actual sound velocity of the ultrasonic wave in the fluid is not known, a value is assumed, a flow rate is measured, correct sensor mounting positions are calculated and the actual sound velocity of the ultrasonic wave is then determined. If the assumed sound velocity differs from the calculated sound velocity by more than a predetermined amount, the assumed sound velocity is adjusted and the procedure is repeated. Therefore, even when the sound velocity of an ultrasonic wave in a particular medium is not known, an actual sound velocity can be calculated. Accordingly, the ultrasonic measuring apparatus can accurately measure the flow velocity and flow rate of a fluid.

Numerical simulation of ultrasonic flowmeters

Abstract: Transit-time ultrasonic gas flowmeters offer several advantages compared to other current flowmeter technology, and they have the potential of being developed into cost-effective and reliable flowmeters. One important step towards implementing more fully the advantages of ultrasonic flowmeter technology is to apply flowmeter simulation models in the design process. A simulation model which describes the signal transmission for a single acoustic beam in an ultrasonic transit-time flowmeter, is described here. Some of the capabilities of the model in predicting several important effects in the functioning of a flowmeter signal transmission channel are demonstrated for a given simplified set of design parameters.

Ultrasound flow rate meter using a phase difference method and apparatus

Abstract: An ultrasound of flow rate meter which uses the phase difference method wherein two ultrasound transducers W1 and W2 are mounted offset but aligned with each other in a tube through which the velocity of flow is to be measured wherein both of the ultrasound transducers are excited in a pulse manner by an oscillator OS2 and wherein receiving amplifiers V1 and V2 are, respectively, associated with the ultrasound transducers W1 and W2. Evaluation devices are connected after amplifier V1 and V2 such that the phase relationship of the signals at the outputs of the receiving amplifiers V1 and V2 is determined during the reception of ultrasound signals. The phase relationship between the signals at the ultrasound transducers is also determined during transmission of ultrasound signals and this phase difference is used as a reference during reception of ultrasound signals.

A New Velocity Algorithm for Sing-Around-Type Flow Meters

Abstract: In many flow metering applications the fluid temperature can change rapidly during the measurements. An example is flow me- tering in district heating systems. These temperature changes will cause fast, large changes of the speed of sound in the fluid. If not recognized, this phenomenon can introduce severe errors in sing-around-type flow meters. The sing-around flow meters used today handle this problem with varying success. Therefore, the algorithm used to calculate the flow velocity from the sing-around frequencies has been modified. This new algorithm compensates for fast changes of fluid temperature dur- ing the sing-around measurement cycle. A complete derivation is given for both laminar and turbulent flow. Test measurements comparing the new algorithm and the conventional one showed a superior perfor- mance of the new algorithm, especially in the case of rapidly changing fluid temperature. \ 4

Low-Gravity Sensing of Liquid/Vapor Interface and Transient Liquid Flow

Abstract: lowgravity (g) gauging of the liquid propellant remaining in a container to an accuracy on the order of one to two percent of reading. Several different container materials and geometries are of interest, but the work reported here deals mainly with tests on internally vaned cylindrical shell acrylic containers capped by hemispherical acrylic or aluminum end domes. Three different ultrasonic sensor techniques and one nucleonic technique presently are among the principal candidates being evaluated as possible solutions to the low-gravity liquid gauging problem. The ultrasonic techniques are as follows: use of a torsional wave sensor in which transit time is proportional to the integral of wetted distance X liquid density; integration of the flow rate output signal of a fast-response ultrasonic flowmeter; and use of multiplexed externally mounted “point-sensor” transducers that sense transit times to liquid-gas interfaces. Using two commercial flowmeters and a thickness gauge modified for this particular project, bench tests were conducted at 1 g on liquids such as water, freon, and solvent 140, including both steady flow and pulsating flow with 40,80, and 120 ms flow pulses. Subsequently, flight tests were conducted in the NASA KC-135 aircraft in which nearly 0-g conditions are obtainable for up to about 5 S in each of a number of repetitive parabolic flight trajectories. In some of these brief low-gravity flight tests freon was replaced with a higherviscosity fuel to reduce sloshing and thereby obtain settled surfaces more quickly. From data obtained in these tests, conclusions have been drawn concerning the likely benefits and limitations of the three ultrasonic techniques. An orbital test of multiplexed point sensors is recommended as a means of verifying the practicality of the noninvasive ultrasonic sensors under prolonged zero-g conditions.

An ultrasonic fluid flow meter

Abstract: In order to make an ultrasonic flow meter more compact, reflecting surfaces 2b, 2c are provided so that ultrasonic signals from transducers 4, 5 travel along a region 2a of the flow path 2 substantially parallel to the axis of that region. A guide 10 may be provided to suppress off-axis modes along that region. Times of flight may be measured by varying the frequency to maintaining constant phase shift upstream and downstream. The timing circuit is also disclosed.

Ultrasonic flow meter

Abstract: PURPOSE:To improve measurement precision at a low flow rate and to improve an SN ratio by providing transmission foil which cuts off the fluid and transmits an ultrasonic wave on the ultrasonic wave passing surface of a main duct. CONSTITUTION:When an electric signal is sent from an oscillation circuit 20 to an oscillator 4, the signal is converted by the oscillator 4 into an ultrasonic wave, which is reflected by a reflector 2 toward a receiver. At this time, at the oscillator 4 reflects the wave at the angle where the directivity is at the highest level, so sound pressure level reaching the receiver is sent efficiently. Further, high sensitivity is obtained by setting the angle of the reflector 2 properly even when the internal diameter of the duct 1 is decreased or when transmission-reception distance is increased so as to improve low flow rate precision. Acoustic waves emitted by the oscillator 4 to the upstream and downstream sides at the same time arrive having a time difference proportional to the flow rate. Those signals are passed through amplifiers 21a and 21b which amplify them and waveform shaping devices 22a and 22b to detect the difference in propagation time by a phase comparator 24, and the difference is calculated by an integrator 25 and outputted. Further, sheets of transmission foil 3, 3a, and 3b smooth the flow of fluid to transmit the acoustic waves, which can be transmitted and received.

Ultrasonic measurement of velocity and/or solids loading

Abstract: A flow meter (10) particularly adapted for measuring the mass flow rate of pulverized coal being introduced into large scale power generation boilers. The meter includes a transmitter (14) which generates a pulsed beam of ultrasonic impulses. A receiver (18) is positioned across the flow field from the transmitter and receives the ultrasound pulses. The meter measures the downstream drift of the ultrasound pulses and their attenuation which is related to flow velocity and concentration, respectively. The instrument includes electronic circuitry (28) for automatically adjusting the relationship between transmitter and receiver, and performs numerical analysis routines on the signal outputted from the receiver to provide a signal related to coal concentration and velocity.

Method and device for processing measured values of ultrasonic flow meter

Abstract: PURPOSE:To judge a difference between abnormal data and variation in measured value due to variation in flow velocity by employing a measured value obtained after the latest abnormal data as normal data when the frequency of continuous detection of abnormal data exceeds a reference frequency value. CONSTITUTION:Received signals R from ultrasonic transmitter and receivers 3A and 3B are outputted C from a counter circuit 7 through a switching circuit 5 and a receiving circuit 6. A propagation time difference computation part 12 computes the propagation time difference between new and old data with the output C and the difference is stored 11. Then, a time difference comparing and deciding means 13 employs the latest time difference data as normal data when the difference is smaller than a reference value, and handles it as abnor mal measurement data and also counts the frequency of continuous detection of abnormal data by a counter 20A when the difference is larger than the refer ence value. Then when the frequency of abnormality detection exceeds the reference value, the measured value obtained after the latest data abnormal data is employed as normal data. Consequently, the difference between abnormal data and variation in measured value with a flow rate is judged.

Calibrating method for transmission type ultrasonic flowmeter

Abstract: PURPOSE:To easily calibrate a transmission ultrasonic flowmeter after its installation in a plant by alternating two probes for calibrations in transmitting and receiving ultrasonic pulses and obtaining a propagation time corresonding to that in reference flow velocity measurement artifically. CONSTITUTION:While two couples of probes 11 and 12, and 13 and 14 for calibration are set at the same distance, an ultrasonic flowmeter is put in operation and a zero adjustment is made by the zero adjusting device 7a of an arithmetic circuit 7 so that the output signal from the arithmetic circuit 7 indicate a zero flow velocity. Then, a computing element 16, a constant input setter 17, and a probe positioning mechanism 18 are provided and a reference flow velocity V, the distance L between probes, an angle theta, and acoustic velocities C and C0 in stationary gas are inputted to the computing element 16. Then, the distances L10 and L20 between the probes 13 and 14, and 11 and 12 are calculated from equations I and II and arithmetic values are used as command signals to control a probe positioning mechanism 18. Thus, the distance L10 and L20 are determined automatically and a calibrating device is connected to downstream-side probe receiving circuits 3 and 4 of the ultrasonic flow meter to make calibrations.

Design of a continuous-wave Doppler ultrasonic flowmeter for perivascular application. Part 1. Probe design.

Abstract: The paper details the specification of an ultrasonic Doppler flowmeter intended for perivascular application and describes the elements of the design of an ultrasonic blood flow transducer. An optimised design is outlined for probes to be used on vessels in the range 5–12 mm. The design is based on the use of continuous-wave Doppler techniques and incorporates a novel polymer ultrasonic couplant. A constrained jet technique is used to test the performance of the probe in vitro and the results indicate that in use velocity profile effects are likely to lead to sensitivity changes of only 3 per cent. A companion paper details the design and performance of the electronic processing system needed for the complete flowmeter.

Measurement of Local Speckle Pattern Displacement to Track Blood Flow in Two Dimensions

Abstract: Pulsed Doppler ultrasonic blood velocity imaging devices suffer from aliasing at high velocities and sizable velocity errors resulting from a lack of knowledge of the angle between the acoustic propagation and blood velocity vectors. We describe a new velocity imaging technique which operates on the envelope-detected echo signal and uses a two-dimensional correlation search method. Several experiments were performed in order to define the potentials and limitations of this technique. The results indicate that it allows resolution of the flow velocity vector in two dimensions and is not subject to aliasing.

Measured value processing method for ultrasonic flow meter

Abstract: PURPOSE:To improve measurement accuracy and to shorten a measurement time by employing a measured value right after the latest abnormality data as normal data when the frequency of continuous detection of abnormality data exceeds a reference frequency. CONSTITUTION:Received signals R from ultrasonic transmitter and receivers 3A and 3B are outputted C from a counter circuit 7 through a switching circuit 5 and a receiving circuit 6. Then, the difference in propagation time between new and old data is computed by a propagation time computation part 12 with the output C. Then when a time difference comparing and deciding means 13 decides that the difference between new and old time difference data is smaller than a reference value, the measured value based upon the latest time difference data is employed as normal data and when not, the up-to-data time difference data is discarded as abnormal measurement data and the frequency of continuous detection of abnormal data is counted 20A. Then, when this frequency of abnormality detection exceeds a reference value, a measured value obtained right after the latest abnormality data is employed as normal data. Consequently, the measurement accuracy is improved.

Plug-type ultrasonic flowmeter

Abstract: The utility model discloses a plug-type ultrasonic flowmeter, which belongs to a non-contact type flowmeter for measuring the liquid flow by the ultrasonic and comprises a sensor, a transmitter, a receiver, a receiving-transmitting converting circuit, a microprocessor and an interface circuit. The utility model realizes the multiple reference rings frequency time difference method mathematical model by the microprocessor, which solves the problems of big error and poor stability of the existing ultrasonic flowmeter. The sensor is plug into the conduit to be measured without the maintenance for a long term. The plug-type ultrasonic flowmeter can automatically display and print the instantaneous and the cumulative flow value, automatically carry out the temperature compensation and automatically correct the flow referring factor. The plug-type ultrasonic flowmeter can measure the liquid with low temperature, corrosion or particle impurity, and can be used for measuring the flow of various liquids in the industry.

Ultrasonic flowmeter combined with a pressure sensor

Abstract: A flow-meter for sensing mass flow rate employs transducers 4, 5 for determining, from the time difference between the time of flight of ultrasonic signal upstream and downstream of a flow path, the velocity of flow and acoustic velocity, and a pressure sensor 6 for sensing pressure in the flow path, the pressure being related to the density From these measurements the mass flow rate may be obtained Both measurements of time difference and of pressure may be made in terms of frequency, enabling interfacing with digital electronics The flow-meter may be used as a domestic gas meter

Temperature correcting method for ultrasonic flow meter

Abstract: PURPOSE:To obtain the correct propagating time even when the vibrator resonance frequency is changed together with temperature by setting the measuring point of the third propagating time to the maximum vicinity of the receiving signal in the system to deduct the time for several waves from the rise of the flow meter to next maximum zero cross point and measure the true propagating time CONSTITUTION:A receiving signal (d) obtained from the ultrasonic flow meter is changed to the signal having the first gate off width (a) by the first gate 29, an obtained receiving signal (e) is compared with the first threshold (b) and the first time measuring completing signal (f) is obtained Thus, when the first propagating time (g) is measured and the first gate receiving signal comes to be the maximum, the second time measuring completing signal (h) is sent, and thus, the second propagating time (i) is measured, the second gate off width (j) is set and the second gate receiving signal (k) is obtained Therefore, the third time measuring completing signal (m) is obtained from the first zero cross point of the signal (k), the third propagating time (m) is measured, the time from the zero cross point to the next zero point equivalent to serveral periods is measured, divided by the number of the included wave and a period signal (o) is obtained

Ultrasonic fluid flow rate motor using the phase difference method

Abstract: An ultrasonic flow rate meter according to the phase difference method, with a two opposing in the flow axis ultrasonic transducers (W1, W2) within a measuring tube formed Stromungsmesstrecke which ultrasonic transducers (W1, W2) clocked are excited by an oscillator (OSZ), and the ultrasonic transducers (W1, W2) individually associated with receiving amplifiers (V1, V2) and this downstream evaluation devices, wherein the phase position of the outputs of the receiving amplifiers (V1, V2) signals occurring is evaluated during the reception of ultrasonic signals. Each of the receiving amplifiers (V1, V2) is permanently connected to its associated ultrasonic transducer (W1, W2), respectively. The phase position between the ultrasonic transducers (W1, W2) applied signals is also evaluated during the transmission of ultrasonic signals and the detected phase difference is used as a reference to which the phase difference is obtained during the reception.

Method for measuring the rate of flow with the aid of ultrasound

Abstract: In the method according to the invention, a measurement section is located between two ultrasonic transducers 1, 2. The two ultrasonic transducers 1, 2 are operated alternately as transmitter and receiver in order to generate two directions of propagation of the ultrasound during each measuring operation. In the case of respectively successive measuring operations, the sequence in which each ultrasonic transducer is operated as transmitter or receiver is permuted. This eliminates errors which otherwise would simulate a through flow even in the event of a stationary medium.

Arithmetic system for ultrasonic flowmeter

Abstract: PURPOSE:To improve the measurement accuracy of an ultrasonic flowmeter by performing specific arithmetic operation under the conditions of the diameter of a transducer fitting part, the internal area of a circular pipe, etc CONSTITUTION:The ultrasonic flowmeter is provided with two kinds of setting means 23 and 24 and an arithmetic means 25 The setting means 23 has a function for setting the internal diameter size C of the fitting parts of a pipe 10 for transducers 13 and 14 The other setting means 24 has a function for setting the area condition of the pipe 10, ie internal diameters A and B measured accurately in two crossing directions An arithmetic means 25 adds the area condition based on the accurate measured internal diameters A and B to a flow rate Q computed from the internal diameter C of the pipe 10 at the transducer fitting parts under the input conditions from the setting means 23 and 24 from an arithmetic equation in a figure (K: flow rate coefficient, N: set oscillation number, Q: fitting angle of transducer, DELTAf: difference in frequency in fluid) to correct an error in the flow rate Q, thereby calculating an accurate flow rate value

Double-flow flow meter for measuring the flow or consumption of a fluid.

Abstract: The flow meter is mounted on the outgoing and return lines of the fluid supply system, so as to make it possible to measure the flows of the outgoing (A) and return (B) pipelines. Means (5) for shaping pulses of the signals representing the flow of the fluid conveyed by the lines (A) and (B) make it possible to supply counting pulses to count-up/count-down means (5). When the number of counting pulses on the line (B) is greater than the number of pulses on the outgoing line (A), the pulses of the return line (B) are put in reserve in order to be taken in to account by the counting means (5). The invention is used for measuring the flow of fuel feeding a moving or stationary engine.

An acoustic method for high precision gas flow measurements

Abstract: An acoustic gas flow measurement method with wide dynamic range (0.1 - 70 m/s) is described. The mean flow velocity, the volume flow rate and the mass flow rate are measured indenpendently of the flow profiles by using long acoustic plane waves propagating upstream and downstream of the flow. A sinusoidal frequency sweep has been chosen for the sound signal, from which the pertinent transit times are obtained by means of a polarity correlator. The results are compared with the results obtained by a precision orifice plate and by a vortex gauge.

Theoretical Analysis of the Ultrasonic Doppler Flowmeter for Measurements of High Flow Velocities

Abstract: A geometric approach is used to analyze the ultrasonic Doppler flowmeter for measurements of flow velocities that are high but yet much smaller than the ultrasound velocity. The approach is based on the calculation of the lransit time difference between the ul- trasonic waves that are reflected from a moving particle at its various positions. Beam divergence is taken into account, and each path of the ultrasonic wave propagation is approximated by two rectilinear com- ponents. It is shown that the Doppler frequency shift is influenced not only by the suspended particle velocity, but also by the mean flow ve- locity of the fluid. This influence is of second order in the flow velocity.