Showing papers on "Ultrasonic flow meter published in 1982"

Some aspects of the relationship between instantaneous volumetric blood flow and continuous wave Doppler ultrasound recordings--I. The effect of ultrasonic beam width on the output of maximum, mean and RMS frequency processors.

Abstract: A theoretical model has been developed to predict the effect of ultrasonic beam width on the output of maximum frequency, mean frequency and rms frequency processors when interrogating blood vessels containing either parabolic or plug flow It is shown that the only way to measure blood flow velocities, and obtain waveforms that are proportional to instantaneous volumetric flow (irrespective of changes in velocity profile) is to use an ultrasonic beam which is uniform over the whole area of the vessel, and to process the Doppler shift signal with a mean frequency detector

Measurement of fluid turbulence based on pulsed ultrasound techniques. Part 2. Experimental investigation

Abstract: An extensive experimental programme in both laminar and turbulent flow was undertaken to examine the validity of all of the major implications of the model of the pulsed ultrasonic Doppler velocimeter for turbulent flow developed in part 1 of this investigation. The turbulence measurements were made in fully developed flow at the centre of a 6·28 cm diameter pipe. The Reynolds number of the flow ranged from 6000 to 40000. The carrier frequency of the ultrasonic velocimeter was 4·7 MHz.Measurements of the turbulence intensity and of the one-dimensional velocity spectra made with the ultrasonic velocimeter are compared with the analysis and with the actual quantities as measured by a hot-film anemometer. The experimental results are in agreement with theoretical predictions.Measurements of one-dimensional turbulence spectra with reduced ambiguity spectra made by the two sample volume methods described in part 1 are presented. The results verify the analysis and indicate that an improvement in the useful dynamic range of the velocity power spectrum of nearly three orders of magnitude can realistically be achieved.

Some aspects of the relationship between instantaneous volumetric blood flow and continuous wave Doppler ultrasound recordings--III. The calculation of Doppler power spectra from mean velocity waveforms, and the results of processing these spectra with maximum, mean, and RMS frequency processors.

Abstract: A method of predicting velocity profiles and hence Doppler relative power spectra (RPS) from mean volumetric flow waveforms using an extension of Womersley's theory is described. The effect on the RPS of using an ultrasound beam which is smaller than the blood vessel is calculated, and comparisons are made between RPS found in this way and experimental RPS measured in a dog model. Finally the effect of making ultrasonic Doppler measurements on complex velocity profiles with different combinations of processing technique and ultrasonic beam size are considered.

A double beam doppler ultrasound method for quantitative blood flow velocity measurement

Abstract: A method for measuring the absolute blood flow velocity waveform is reported. Two independent beams of ultrasound illuminate a vessel simultaneously, producing complementary Doppler signals. The two Doppler frequency shift signals are processed by subtraction and addition at the receiver. The optimum probe position where blood flow velocity is detected can be found as the position where the subtractor output reaches zero. At this position the blood flow velocity is the output from the adder. By this means the influence of the angle between the probe and blood flow is eliminated so that a quantitative measurement is obtained. Both in vitro and clinical results are reported.

Real-time measuring method and apparatus displaying flow velocities in a segment of vessel

Abstract: The invention relates to a Doppler velocimeter comprising a transmitter composed of a plurality of independent transducers for generating beams of ultrasonic energy, an ultrasonic generator for generating a plurality of noise signals, each noise signal being independent of the other, and a receiver for receiving beams of ultrasonic energy reflected from a target. Each noise signal is applied to several of the plurality of transducers and maintained separately upon generation of the beams of ultrasonic energy. Received ultrasonic energy is processed through the use of groups of dual correlators, further processed and displayed. The invention finds an application in the real-time display of blood flow velocities in a segment of blood vessel.

Analog ultrasonic flowmeter

Abstract: A meter for measuring the velocity of a fluid by ascertaining propagation periods of acoustic wave packets transmitted therein, the meter including a pair of transducers for disposition in the fluid, a transmitter for transmitting a packet between the transducers in an upstream or downstream direction designated by an up/down signal at each time designated by a transmit signal and a receiver for developing a received signal marking the time of receipt by a transducer of each packet, the times being marked so as to avoid amplitude and half-cycle ambiguity errors. The meter also includes a phase detector for comparing the received times with those marked by a reference signal to develop early and late pulses, a decoder and a pair of integrators for developing from the pulses a pair of integrated signals representing changes in the upstream and downstream propagation periods, another integrator for combining the integrated signals to develop a signal representing the acoustic velocity of the fluid and an amplifier for combining the integrated signals to develop a signal representing the velocity of the fluid. Further, the meter includes a ramp generator for developing the up/down signal, a ramp signal and the transmit signal from the acoustic velocity signal and the combination of a multiplexer, a multiplier and a comparator for developing the reference signal, the multiplier for developing a signal inversely proportional to the acoustic velocity signal and multiplying it by a signal developed by multiplexing the integrated signals.

Ultrasonic flowmeter for clean and dirty fluids

Abstract: An ultrasonic flowmeter for accurately measuring the flow rate of clean or dirty industrial process fluids passing through a pipe provided with upstream and downstream transducers. A transmission signal produced by a high-frequency generator acts to energize the transducers which are alternately excited at a relatively low switching rate whereby a beam emitted by the excited transducer is propagated through the fluid at an angle to the flow axis of the pipe and is intercepted by the other transducer to yield a received signal that is displaced in phase from the transmission signal to an extent depending on the transit time of the beam which reverses direction during each switching cycle. The received signals from the transducers are converted into a square wave that is compared to a wave derived from the transmission signal to produce a comparison output which is fed through a low-pass filter to exclude the high frequency content thereof. The filter yields a square wave in which the voltage drop between the upper level of the wave representing beam transit time in one direction and the lower level representing beam transit time in the reverse direction, reflects the time delay difference between these transit times. The flow rate of the fluid is then derived from the time delay difference.

Borehole ultrasonic flow meter

Abstract: A borehole tool incorporates an ultrasonic flow measuring device which enables calculation of the rate of flow of material through various perforated intervals of a well casing as a function of depth. Fluid flow rate is proportional to the difference in travel time of a pulse-type ultrasonic signal over a fixed distance in opposite directions through the fluid.

Method and apparatus for calibrating flow meters

Abstract: The specification discloses a method and apparatus for calibrating liquid flow meters of all types. The system includes a scale for dynamically determining the weight of a liquid flowing through a flow meter, together with means for measuring the flow through the flow meter being tested. In the case of a glass tube flow meter, a float detection system is used, whereby the operator will set the flow through the flow meter to a desired point, use the float detection system to make certain the float stays in a fixed position during the test, as well as to locate the float from a reference point, and use the system to measure the flow through the flow meter during a fixed period of time, thereby obtaining a reading, in engineering units, for each predetermined position of the float.

Evaluation of a Wall-Flow Direction Probe for Measurements in Separated Flows

Abstract: The upstream-downstream flow direction intermittency is an important parameter that can quantitatively describe the stages of flow separation. This paper gives an improved design for a wall-flow-direction probe. Intermittency measurements made using this modified probe show agreement within experimental uncertainties with direct measurements made using a LDV, although both the unmodified and modified probe designs produce results that are consistently higher than those for the LDV.

Method and apparatus for conducting flow measurements on flowing media according to the ultrasonic doppler method

Abstract: Due to a different configuration of the ultrasonic beam as well as different signal gate adjustments, two different doppler signal collection regions (V m1 , V p ) of the flowing medium are selectable. To further develop the state of the art, without excessively increased technical outlay, at least the flow velocity (v) and/or the flow cross-sectional area (F) are to be measured, preferably simultaneously with the volume flow (Q), independently of the irradiation angle of the ultrasound into the flowing medium. This is achieved through selection of a third doppler signal collection region (V m2 ), power measurements (P m1 , P p , P m2 ) from all three regions (V m1 , V p , V m2 ) and the calculation from the powers together with additional known parameters of the signal collection regions such that, with cancellation of the angle-dependency, the respectively desired flow quantity (F, v, Q) directly results. A preferred implementation is for the purpose of diagnosis of blood flow.

Ultrasonic air flowmeter for motor vehicles

Abstract: An ultrasonic air flowmeter for an internal combustion engine of a motor vehicle includes at least two ultrasonic transmitter-receivers. One of the ultrasonic transmitter-receivers generates ultrasonic waves toward an upstream of an air flow so that a radiation direction of the ultrasonic waves obliquely intersects a direction of the air flow. On the other hand, the other ultrasonic transmitter-receiver generates ultrasonic waves toward a downstream of the air flow in the same manner. A difference in phase between outputs of the receivers is detected to obtain a rate of the air flow.

Positive displacement volumetric compressible fluid meter

Abstract: To measure low volumes of gas flow in high-pressure systems a conventional gas meter is incorporated within a high-pressure container. Connections from inside the high-pressure container are connected to a warning system outside the container to alert the operator when too great a volume of gas is flowing through the meter and a restriction of the size of the outlet to the heavy-duty container prevents the damage to the meter which is designed to measure small volumes and is relatively delicate.

Measurement of blood flow using Doppler-shifted ultrasound

Abstract: Ultrasonic fields can be used to measure the complex dynamic flow patterns in a wide range of intact blood vessels with calibres ranging from fractions of a millimetre to several centimetres. Many ...

Liquid flow meter

Abstract: To measure a wide range of flow rates, and particularly such low flow rates as 0.5 liters per hour, while being able to accurately also measure rates of about 100 liters per hour, fluid is introduced axially into a rotor (14, 36, 40) which has outlet openings (24, 36, 45) positioned at their circumference, the rotor being rotated by reaction on the rotor upon fluid flow from the outlet openings. The rotor operates within a fluid flow chamber (15) from which is conducted outwardly through a duct positioned thereabove. Inflow of fluid may be guided for linear flow by guide ribs (13). The rotor may be a hollow disk-like structure (FIGS. 1-3) with spiral guide vanes therebetween, or a T-shaped tubular structure (FIGS. 4-6). If fuel consumption of an internal combustion engine is to be measured in which pressurized fluid is supplied to the engine and excess returned, two such flow meters can be combined on a common shaft, with respectively oppositely facing outlet openings (36, 45), so that differential flow only is being measured, hence accurately measuring fuel consumption by the engine. Rotation of the rotor is sensed by an electro-optical sensor (29, 37).

Ultrasonic flowmeter offers new approach to large-volume gas measurement

Abstract: Objective was to provide a measurement tool for performing transmission-pipeline efficiency studies and aid in gas control and intercompany gas transfer. A single path, contrapropagating ultrasonic flowmeter can be calibrated to accurately measure gas flow rates in large-diameter pipelines over a wide range of flows. The agreement between a multiple-run orifice measurement station and the ultrasonic flowmeter is within + 0.5%. Uncertainty in the meter calibration is a function of the ability to predict the flow profile of the gas stream.

Ultrasonic three-dimensional tidal current meter

Abstract: PURPOSE:To grasp the speed and direction of a tidal current in three dimensions by emitting ultrasonic wave beams in four front and rear, and left and right directions of a ship at adequate angles to the surface of water, and then obtaining speed information. CONSTITUTION:Ultrasonic wave beams are sent to the front and rear of a ship S at a standstill in directions OA0 and OB0 at optional angle alpha. For the measurement of a tidal current which has a velocity V0 and an angle phi0 to an Y axis, the velocity V0 is found from speed components VA and VB in directions OA0 and OB0 of an ultrasonic flow meter. The components of the velocity V0 are as shown in the figure. Similarly, the speed component VX in the left and right (X axis) direction of the ship is found by using two beams in the left and right direction, so the velocity V0 and phi0 of the tidal current or the azimuth of the V0 projected on an XY plane is also found from the found VX, YY, and VZ.

Ultrasonic flow meter

Abstract: PURPOSE:To measure an extremely low flow rate by supporting an ultrasonic transmitter and a receiver with a sound absorbing material at a prescribed facing angle. CONSTITUTION:An ultrasonic transmitter 1 and a receiver 2 are stuck to a base plate 12 at 160-170 deg., preferably 167 deg. opposing angle theta, and the base plate 12 is coupled with a sound absorbing material 13 having a low elastic modulus. As a result, when facing distance l between the transmitter 1 and receiver 2 varies, the influence of a standing wave is eliminated and the adjustment of an oscillating circuit 3 which drives the transmitter 1 is facilitated; and further the receiver 2 obtains a signal stable against slight variation in oscillation frequency.

Current Meter Calibration And Three-Dimensional Displacement Effects

Abstract: Current meters are mounted on a much shorter suspension during the calibration than during field measurements and a three-dimensional flow around the end of the suspension occurs. This flow is analysed by potential flow theory. The situation in the channel corresponds to a boundary value problem. This problem is solved by using double Fourier series to describe source density and potential. The velocity induced by the mounting rod is calculated in the region of the rotor of the current meter. The influence of the distance between the current meter and the end of the mounting rod is investigated for one channel geometry. The computed results are verified by measurements in a towing tank. Recommendations are given concerning a correction of the calibration results in small rating tanks and concerning a minimum distance of the current meter from the end of the rod.

Ultrasonic flowmeter operates independently of propagation speed - using PLL circuit for phase shift regulation, comprising phase comparator, filter and VCO

Abstract: An ultrasonic flow meter has two ultrasonic transducer receivers placed one upstream and one downstream of an ultrasonic transducer source. A phase angle detector measures the phase shift between the ultrasonic waves flowing with or against the measurement flow and acquired by the receivers. The phase measurement is not dependent on the speed of propagation of the ultrasound in the flow medium. The arrangement contains a phase locked loop (PLL) circuit (7,8,9) in a loop contg. the same transducer (2) and one (3) of the receivers. The PLL circuit maintains a constant phase shift between the emitted and received ultrasonic waves in the loop. The PLL circuit contains a phase comparator (7), a low pass filter (8) and a voltage controlled oscillator (9).

Ultrasonic flow meter for gas

Abstract: PURPOSE:To precisely measure the flow rate of a fluid through ultrasonic wave transmission and reception, by completely straightening a turbulent flow, specially a rotary flow of a fluid to be measured by the successive constitution of a large-diameter opening part, a straightening device, and an arc-shaped throttle part. CONSTITUTION:A fluid to be measured flows into the opening part 1 of a flow meter body (a) and is supplied to a straightening device 6 to straighten a turbulent and a rotary flow; and a trailing practicable throttle part 5 reduces the sectional area of the fluid to accelerate the straighening, and the fluid is transported to a fluid measurement part 2. Continuous ultrasonic waves driven by oscillators are transmitted slantingly from the up side and down side of the fluid to be measured, so ultrasonic-wave receivers 4 provided at opposite positions receive the ultrasonic wave signals. According to the velocity of the fluid to be measured, the ultrasonic waves received by the ultrasonic-wave receivers 4 provided at the up side and down side differ in phase difference and measurement results of two couples of ultrasonic-wave transmitting and receiving mechanisms (b) are operated to measure a desired flow rate.

Ultrasonic flow meter

Abstract: PURPOSE:To obtain a device which makes a maintenance check on a detection part while securing detection precision by arranging a coule of pipe member, deviated at a prescribed angle, at a flow passage for a fluid to be measured, and then attaching flow rate detecting elements in the inside of them detachably. CONSTITUTION:A couple of pipe members are arranged, opposite each other, on the same axial line deviated previously at an angle theta in the wall of a water channel wherein a fluid to be measured is transported. Each pipe member is fitted with a valve device, and a flow rate detection body connected to a flow meter body is inserted detachably into the end part of the pipe member. For example, embedded pipes 34 and 34 arranged oppositely in a cluvert 30 each have a fitting flange 40 at an end part 38 to fit a valve 42, and a short pipe 44 is fitted in a watertight state through a flange 46. Then, an insertion pipe 48 is equipped,and a fluid contact type probe 52 equipped in the insertion pipe extends into a flow passage at an opening part 50; and a fitting flange 54 at the other end part is engaged in a watertight state with the flange 56 of the short pipe, and an O ring 58 is provided between the short pipe 44 and insertion pipe 48.

Fitting method for ultrasonic flow meter

Abstract: PURPOSE:To obtain an easy and secure positioning means for an embedded pipe of embedding one long-sized pipe body at a prescribed angle to a flow direction, fixing it on a measurement wall, and then cutting its part in a culvert along the internal wall of the culvert CONSTITUTION:In the opposed wall parts 52 and 54 of a duct 50 wherein a fluid flows, a couple of large-diameter opening parts 56 and 58 are provided shifting in position, and then one long-sized pipe body 64 provided with flanges 60 and 62 parallel to both end parts is inserted into an embedded pipe into the opening parts 56 and 58 The pipe body 64 while held horizontally is fixed at a desired angle theta to a flow direction, and a consolidating material 65 is flowed into gap parts between the pipe body 64 and opening parts 56 and 58 After consolidation, the pipe body 64 is cut along the surfaces of side wall parts 52 and 54 to obtain embedded pipes 66 and 68 whose cut ends are in parallel to the flow direction of the fluid

Ultrasonic flow meter

Abstract: PURPOSE:To simplify a circuit constitution and to enable to perform a high by precise measurement, by a method wherein a device is constituted such that, based on an ultrasonic receiving signal, an amount depending upon only a velocity of flow of a fluid is detected and operated to find a velocity of flow. CONSTITUTION:A pair of ultrasonic probes, mounted in a manner to incline against a flux, are connected to a transmitting and receiving devices 13, and a forward propagation direction of an ultrasonic wave is switched to and from a reverse propagation direction to send a frequency for a full period or a plurality of periods to an operating means (micocomputer) 14. Their respective single around periods are formed from a forward direction and a reverse direction frequency from the transmitting and receiving device 13 by means of a first operating part 15, an amount depending on only a velocity of flow of a fluid is detected by means of a second operating part 16, and a difference in a frequency is found by means of a third operating part. A rate of flow is found through the addition of a correction on an actual flow conduit by means of a fourth operating part, is outputted to a meter 21 through a DA converter 19, and simultaneously, is outputted to an integrating meter 20 via an integrating circuit. This simplifies a circuit constitution and enables to perform a highly precise measurement.

Supervising method and its device of performance in steam power plant

Abstract: PURPOSE:To improve reliability of flow data and obtain high reliability for supervising performance, by connecting a differential pressure type flowmeter and ultrasonic flowmeter or electromagnetic flowmeter, detecting a feed water flow amount, to the arithmetic unit of a flow data correction device. CONSTITUTION:Performance in a steam power plant is supervised by a pressure detector 9, temperature detector 10, output detector 11, flow detector 12 and heat rate arithmetic unit 8. A differential pressure type flowmeter 120 and ultrasonic flowmeter or electromagnetic flowmeter 121, detecting a feed water flow amount, are concurrently provided in a main feed water piping, and a detectedvalue of the differential pressure type flowmeter is corrected on the basis of a differentce between the both flowmeters. In this way, an aging error arising from adhesion of scale is accurately corrected, and reliability of flow data can be improved, then high reliability can be obtained for supervising performance in the steam power plant.

Analysis of Instantaneous Milk Flow Rate Patterns

Abstract: MEASUREMENTS of instantaneous milk flow rates from unsupported teats (ie, linerless teat cups) and corresponding analysis of flow charcteristics are presented in this report Milk flow measurements were made with an ultrasonic flow meter, using techniques described in a previous report (Delwiche, Scott, and Drost, 1980) Data were gathered according to a V fac-torial experiment design, conducted over 16 days on four cows Parameters investigated were pulsation frequency, 10 and 03 Hz; pulsation ratio, 63 and 42 percent milk-ing vacuum, 51 and 41 kPa; and quarter, front (right) and rear (left) Milk flow patterns from each test are divided into three stages: the low flow beginning stage (stage 1), the high average flow rate stage (stage 2), and the tapering off stage (stage 3) Within each stage, se-quences of four to 15 milk flow and vacuum pulses are analysed Treatment effects during stages 1 to 3 are tested for significance by analysis of variance Peak and average milk flow rates per pulsation cycle are significantly higher for the lower pulsation frequency (03 vs 10 Hz) Similarly, the higher vacuum level (51 vs 41 kPa) yielded significantly higher flow rates Differences due to the ef-fects of pulsation frequency are greater than differences due to milking vacuum level Milk flow rate patterns from unsupported teats show distinct smooth muscle ac-tivity affecting flow rate characteristics Contractions of smooth muscles in the teat and at the teat end produce rhythmic oscillations of the peak milk flow rate from pulse to pulse and determine the overall shape of each milk pulse