Showing papers on "Ultrasonic flow meter published in 1978"
01 Jan 1978
TL;DR: In this article, the application of laser-Doppler anemometers to investigations of particulate flow systems is discussed and the basic principles of LDA-measurements in particulate two-phase flows are outlined.
Abstract: The present paper provides an introduction into the application of laser-Doppler anemometers to investigations of particulate flow systems. The basic principles of LDA-measurements in particulate two-phase flows are outlined and it is shown that correct LDA-measurements require the optical system to consist of two parts that permit the information from the fluid velocity field to be separated from the information relating to the properties of the moving particles. The various information on particulate flow systems which is contained in the optical signals is explained and electronic processing systems are introduced that permit this information to be extracted.
16 citations
TL;DR: A totally implantable telemetry system utilizing custom micropower monolithic integrated circuits has been developed to measure instantaneous pulsatile blood flow in the major arteries of animals to provide a new and necessary tool for accurate quantitative measurements in the study of cardiovascular disease.
Abstract: A totally implantable telemetry system utilizing custom micropower monolithic integrated circuits has been developed to measure instantaneous pulsatile blood flow in the major arteries of animals. The device utilizes the Doppler effect at ultrasonic frequencies to achieve a flowmeter possessing small size and weight, low power consumption, inherent accuracy, and long-term stability. The integrated circuit electronics package occupies a volume of 3.8 cc and requires a power consumption of 10 mW from a single 135 volt mercury cell. The volume of the entire implantable flowmeter package is less than 36 cc. As a micro-miniature radio-telemetry system, the flow-meter can be totally implanted within the body, thereby eliminating the need for wires penetrating the skin, a serious problem with "back-pack" flowmeters due to danger of infection. The implantable flow-meter system provides a new and necessary tool for accurate quantitative measurements in the study of cardiovascular disease. It has been used in the study of transplanted heart rejection to monitor blood velocity in the major arteries of doB
14 citations
TL;DR: Temperature increases on the body surface from the use of two different ultrasonic Doppler blood flow meters were determined experimentally using a thermographic method and approximate agreement in the values of the temperature increase was shown.
Abstract: Temperature increases on the body surface from the use of two different ultrasonic Doppler blood flow meters were determined experimentally. Using a thermographic method it was shown that the temperature increase can be significant. Two continuous wave ultrasonic Doppler blood flow meters induced temperature increases on the body surface of 12.5°C and 2.3°C respectively, after an insonation time of 100 sec. Theoretical estimates and experimental results have shown an approximate agreement in the values of the temperature increase.
10 citations
01 Jan 1978
TL;DR: In this article, an important shortcoming of the conventional laser Doppler method is that it furnishes the instantaneous velocity at a single point in the fluid, and to obtain the complete flow pattern, the experiment has to be repeated for different regions of the flow field.
Abstract: An important shortcoming of the conventional laser Doppler method is that it furnishes the instantaneous velocity at a single point in the fluid. To obtain the complete flow pattern, the experiment has to be repeated for different regions of the flow field (1) ~ (6).
10 citations
Patent•
10 Aug 1978
TL;DR: In this paper, an additional cross-member was proposed to improve the regularity of the vortex shedding from the bar and hence the accuracy of the meter reading, and the provision of the additional crossmember improved the accuracy.
Abstract: A fluid flow meter, for example for measuring the velocity of an air flow, comprises a flow duct having a transverse vortex-shedding bar, the ultrasonic or other detector means for sensing the shedding of Karman vortices from the bar as the fluid flow passes the bar, and for converting the alternating output signal of the detector means into a signal of square-wave form of operating a digital counter, and one or more additional cross-members extending across the flow duct downstream of the flow section where the vortex-sensing means operates, the additional cross-member extending transversely to the vortex-shedding bar and being of cylindrical or aerofoil cross-section, or of rectangular or other cross-section having a flat upstream face parallel to the bar. The provision of the additional cross-member is found to improve the regularity of the vortex-shedding from the bar and hence the accuracy of the meter reading.
7 citations
TL;DR: In this paper, an approach for measuring the velocity of flow of a gas is described, which consists of two ultrasonic probes arranged opposite to one another and transmitting pulses following upstream and downstream paths which are inclined with respect to the direction of flow.
Abstract: Apparatus, for measuring the velocity of flow of a gas, is of the type comprising two ultrasonic probes arranged opposite to one another and transmitting pulses following upstream and downstream paths which are inclined with respect to the direction of flow. A commutation device which enables these two paths to be established is actuated in such a way as to effect change-over of the probes both on transmission and on reception, the commutation command signals being phase shifted with respect to the transmission pulses.
7 citations
Patent•
01 Sep 1978
TL;DR: In this article, the authors proposed a test and calibration method to eliminate the deteriorating influence on the flow rate measurements by arranging a normal flow meter and a sonic nozzle upstream and downstream of a passage, respectively.
Abstract: PURPOSE: To accomplish the test and calibration in a simple but highly accurate manner by arranging a normal flow meter and a sonic nozzle upstream and downstream of a passage, respectively, thereby to eliminate the deteriorating influence upon the flow rate measurements. CONSTITUTION: Atomospheric air or other gases are compressed by a compressor 5, and a storage tank 6, which can be held at a necessary pressure, is charged with the compressed air or other gases through a suitable filter 4 for filtering dusts, mists and the like. The resultant fluid is discharged under a sonic condition into the atmosphere from a downstream standard sonic nozzle or a sonic nozzle 3 to be tested through a flow meter to be tested or a standard flow meter 2, which is arranged at a downstream position. Incidentally, the sample may be either the flow meter 2 or the sonic nozzle 3, and the standard element in that case is calibrated in advance by another method. As a result, the disturbing phenomena or other deteriorating influences due to the provision of the sonic nozzle upstream of the flow meter are eliminated so that the testing and calibrating operations can be accomplished in an easy but highly accurate manner. COPYRIGHT: (C)1980,JPO&Japio
6 citations
01 Jan 1978
TL;DR: In this article, a doppler shift flowmeter was developed for measuring coal slurry flow in coal g asification/ liquefaction plants, where ultrasonic energy transmitted through the pipe wall is scattered by particles and received by a second transducer.
Abstract: A doppler shift flowmeter is under development for measuring coal slurry flow in coal g asification/ liquefaction plants. Ultrasonic energy transmitted through the pipe wall is scattered by particles and received by a second transducer. signal is narrow band noise displaced in frequency from the transmitted signal. of the composite scattered and leakage signal yields a difference frequency spectrum. Signal enhancement effects of in-phase multiple wall reflections are demonstrated. A simple zero crossing counter to determine an a verage frequency of the noise spectrum yields flow rate with a statistical error E where, F, is the count rate and, T, the integration time. The received Coherent detection
3 citations
Patent•
04 May 1978
TL;DR: In this paper, the authors provide an apparatus for measuring flow rate of a fluid, in which a frequency signal proportional to the flowing velocity of the fluid is supplied to a time constant circuit, wherein time constant of said circuit is changed by altering the time periods when a semiconductor switching circuit is closed and opened.
Abstract: PURPOSE:To provide an apparatus for measuring flow rate of a fluid, in which a frequency signal proportional to the flowing velocity of the fluid is supplied to a time constant circuit, wherein time constant of said circuit is changed by altering the time periods when a semiconductor switching circuit is closed and opened, whereby performance of the time constant circuit can be improved
2 citations
01 Oct 1978
TL;DR: In this paper, a novel oscillating pipe system was developed to provide dynamic calibration wherein small sinusoidal signals with amplitudes of 05 to 10% of the steady state flow were added to the steady-state flow by oscillating the flowmeter relative to the fixed pipes in the flow system.
Abstract: A novel oscillating pipe system was developed to provide dynamic calibration wherein small sinusoidal signals with amplitudes of 05 to 10% of the steady-state flow were added to the steady-state flow by oscillating the flowmeter relative to the fixed pipes in the flow system Excellent agreement was obtained between the dynamic velocities derived from an accelerometer mounted on the oscillating pipe system and those sensed by the flowmeter at frequencies of 7, 19, and 30 Hz Also described were the signal processing techniques used to retrieve the small sinusoidal signals which were obscured by the fluid turbulence
TL;DR: In this article, a tapered variable area flow meter with a diameter ratio scale is used to make real-time NO(2) flow measurements without requiring prior experimental calibration of the flow meter.
Abstract: Measurements of NO(2) flows are made without requiring prior experimental calibration of the flow meter. A tapered, variable area flow meter with a diameter ratio scale is used to make the real-time NO(2) flow measurements. The necessary parameters and calculations used to determine the viscosity and density of the flowing N(2)O(4)2NO(2) gas are presented. The limits of error associated with these parameters and errors associated with controlled flow measurement conditions are considered. Disregarding the scale reading error, which depends on the flow meter utilized, the limits of error are found to yield a measurement error less than 7%.