The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 16, 1991
Filed:
Dec. 11, 1989
Frederick H Rambow, Houston, TX (US);
Shell Oil Company, Houston, TX (US);
Abstract
A method and apparatus for detecting fluid flow behind an acoustically reflective structure using pulse echo techniques which do not depend upon measurement of a Doppler effect. A transducer is provided for generating a high frequency beam of acoustical energy in the form of pulses. The transducer is placed proximate, preferably adjacent, the reflective structure such that the acoustic beam is directed toward such structure. A transducer is also provided for detecting the acoustic reflections of the pulses, proximate the position from which the pulses originated, and generating corresponding electrical signals. An electric circuit is provided for subtracting a pair of acoustic reflection signals separated by a short interval of time to produce a difference signal from which the presence or absence of fluid flow behind the acoustically reflective surface can be determined. In the preferred embodiment, a preselected number of the difference signals are 'stacked' by adding the absolute values of such signals to produce a 'stacked' signal trace which is more susceptible to evaluation, especially for determination of relative flow velocities.