Ultrasonic Mass Flowmeter

Lynnworth, L.C.; Pedersen, Norman

doi:10.1109/ultsym.1972.196034

Cited by 9 publications

(3 citation statements)

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“…The motivation may include delay lines for avoiding the transducer's phase aspects in the reflection process [1], the use of buffers for high temperature measurements [2] (then one buffer only is normally exploited), and the use of buffers as reference materials for obtaining the sample's acoustic impedance [3], where the acoustic impedance Z is the product of the sound speed c and the density ρ. Also, buffers made of multiple materials are sometimes used [4], but these tend to reduce significantly the energy of the acoustic wave encountering the sample due to the multiple reflection process [5].…”

Section: Introductionmentioning

confidence: 99%

Acoustic methods for obtaining the pressure reflection coefficient from a buffer rod based measurement cell

Bjorndal¹,

Frøysa

2008

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Abstract-The known acoustic methods for obtaining the pressure reflection coefficient from a buffer rod based measurement cell are presented, along with 2 new generic approaches for measuring the pressure reflection coefficient using 2 buffer rods enclosing the liquid to be characterized in a symmetrical arrangement. An acoustic transducer is connected to each of the buffer rods. The generic approaches are divided into a relative amplitude approach and a mixed amplitude approach. For the relative amplitude approach, families of 4, 5, or 6 echo signals can be used to obtain the pressure reflection coefficient. The mixed amplitude approach uses specific information about the transducers and/or the electronics sensitivities in receive mode to obtain the pressure reflection coefficient using families of 3, 4, 5, or 6 echo signals. Some of the new methods from the relative amplitude approach imply a reduced uncertainty relative to the previously known ABC method. The effect of the liquid attenuation, digitizer bit resolution, and the signal-to-noise ratio on the uncertainty characteristics of the pressure reflection coefficient are discussed, along with a discussion of the suitability of the various methods for different buffer materials.

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Section: Introductionmentioning

confidence: 99%

Acoustic methods for obtaining the pressure reflection coefficient from a buffer rod based measurement cell

Bjorndal¹,

Frøysa

2008

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…In Lynnworth and Pedersen (1972), Rychagov et al (2002) and Jensen (1981) and Deventer (2004) a reference path approach is applied to monitor the excitation variations. The part of the signal that is reflected from a reference interface of constant properties can be used to standardize the received signal and negate excitation variations.…”

Section: Reference Reflection Methods (Rrm)mentioning

confidence: 99%

Ultrasound-based density determination via buffer rod techniques: a review

Hoche¹,

Hussein²,

Becker³

2013

J. Sens. Sens. Syst.

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Abstract. The review presents the fundamental ideas, assumptions and methods of non-invasive density measurements via ultrasound at solid-liquid interface. Since the first investigations in the 1970s there has been steady progress with regard to both the technological and methodical aspects. In particular, the technology in electronics has reached such a high level that industrial applications come within reach. In contrast, the accuracies have increased slowly from 1-2 % to 0.15 % for constant temperatures and to 0.4 % for dynamic temperature changes. The actual work reviews all methodical aspects, and highlights the lack of clarity in major parts of the measurement principle: simplifications in the physical basics, signal generation and signal processing. With respect to process application the accuracy of the temperature measurement and the presence of temperature gradients have been identified as a major source of uncertainty. In terms of analytics the main source of uncertainty is the reflection coefficient, and as a consequence of this, the amplitude accuracy in time or frequency domain.

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“…The electronic approach to measuring V utilizes a modified Panametrics Model 6000 instrument. This instrument transmits pulses sequentially upstream and downstream at two phase locked repetition frequencies whose periods are proportional to the times of flight t 1 and t 2 between transducers. By timing a large number of periods, t and t are measurable to high precision (resolution = Ins).…”

Section: Nadc-80z54-60mentioning

confidence: 99%