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:
Jan. 23, 1996
Filed:
Aug. 09, 1993
Michael Greenstein, Los Altos, CA (US);
Hewlett E Melton, Jr, Sunnyvale, CA (US);
King-Wah W Yeung, Cupertino, CA (US);
Hewlett Packard Company, Palo Alto, CA (US);
Abstract
Piezoelectric elements in a transducer array are individually excited and used to sense the back-scattered signal from fluid flowing within an interrogation volume. The array is preferably a 2-D phased array with a pitch no greater than one-half the acoustic wavelength of the interrogation signal. By activating the transducer elements as a pattern of concentric rings as viewed from a point of interrogation, and by suitable phasing and range-gating of an interrogation signal, a substantially spherical interrogation volume (SIV) is created. The return signal from the SIV provides an isotropic indication of the speed of flow of the fluid. The focussing distance along an interrogation axis can be changed by changing either the size of the aperture created by the pattern of activated elements or their relative phasing. The interrogation direction can be angled off-axis by activating the transducer elements in a pattern of concentric ellipses. The interrogation axis itself may also be moved off-center by translating the pattern of activated elements. By deforming the activation pattern of the transducer elements from concentric rings to concentric ellipses, the long axes of ellipsoidal interrogation volumes (EIV) can be rotated. The back-scattered signals from these rotated ellipsoidal interrogation volumes indicate the direction of fluid flow.