Panametrics, Inc.

Ge Infrastructure Sensing, Inc.

James E Bradshaw

Lawrence C Lynnworth

Norman E Pedersen

James E Matson

Xiaolei Shirley Ao

Jeffrey Tilden

Steven A Lynnworth

Christopher C Doyle

John L Seger

A flow measurement system including at least first and second ultrasonic transducers coupled to an existing conduit, a damping material about the conduit between the first and second ultrasonic transducers to prevent crosstalk, a damping material about the conduit upstream of the first ultrasonic transducer to attenuate system background noise travelling in the conduit at large, and a damping material about the conduit downstream of the second ultrasonic transducer to attenuate system background noise travelling in the conduit at large.

Flow measurement system with reduced noise and crosstalk

An apparatus and method for measuring gas flow velocity through a high stack employs ultrasonic transducers. The transducers are placed on opposite ends of a diameter several hundred feet up, with a small vertical separation L between the transducers. Apparatus for measuring acoustic velocity in the stack gas over short path lengths is also included.

Process and apparatus for ultrasonic measurement of volumeric flow

An acoustic burst with a predetermined amplitude envelope is triggered by a square wave signal and transmitted upstream or downstream to a transducer connected to an adaptive control system which tracks the midpoint of the received envelope. The received signal is rectified and fed via a polarity reversing circuit controlled by the square wave to an integrator whose output level controls the frequency of the square wave. The burst transit time is measured to the next zero crossing of the received signal following the half cycle transition point of the square wave.

Acoustic flowmeter with envelope midpoint tracking

An ultrasonic system that measures either the impedance of a fluid or liquid level utilizes moderately directional, bulk SV mode sound waves generated by a transducer and propagated in a homogeneous, flaw-free solid member. The SV wave propagates in the solid along a zigzag path that reflects at a solid-fluid interface in at least two areas and at an angle of incidence that exceeds the first critical angle by at least five degrees and is less than the second critical angle by at least ten degrees. The attenuated amplitude of the wave due to acoustic coupling between the solid and the fluid measures the impedance or an impedance related parameter of the fluid. The system preferably includes a second acoustic path that serves as a reference to compensate for changes in parameters such as temperature, the nature of the fluid, the transducer, the transducer coupling, and residues or corrosion at the solid-fluid interface. In another form, the reference mechanism is a series of reflections from notches in the solid member. For liquid level measurement desensitized to variations in the liquid impedance, the solid is an elongated member that is oriented at an oblique angle, or is parallel to, the surface of the liquid. Other liquid level measurement systems utilize multiple receivers or reflectors located at the points of reflection of the zigzag wave.

Ultrasonic system for measuring fluid impedance or liquid level

An ultrasonic flowmeter for determining fluid flow velocity within a conduit by determining the difference in transit time between interrogating ultrasonic pulses transmitted upstream between a pair of transducers and transmitted downstream between them. A high frequency clock pulse operating for one or more cycles of interrogation allows for accurate digital computation.

Ultrasonic flowmeter

In the acoustic flowmeter apparatus disclosed herein, repetitively gated bursts of relatively high frequency acoustic energy are transmitted between upstream and downstream transducers in a conduit in which flow is to be measured, the transmission being alternately in an upstream and a downstream direction. The received signals are amplified and subjected to narrow band filtering so as to extract an essentially continuous component at the high frequency, preserving phase information. By measuring the relative phase shifts of the upstream and downstream transmissions, a measurement proportional to flow rate is obtained. In the preferred embodiment, the sum of the transit times is measured by measuring the phase shifts of the principal repetition frequency modulation component of the received signals.

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Tyngsboro, MA, United States of America

James E Bradshaw