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:
May. 28, 1985
Filed:
Feb. 28, 1983
Gillies D Pitt, Saffron Walden, GB;
Roger J Williamson, Harlow, GB;
David N Batchelder, London, GB;
Arulanandam M Prabakaran, Ayanavaram Madras, IN;
International Telephone & Telegraph Corp., New York, NY (US);
Abstract
In order to determine the vortex shedding frequency, from which the fluid flow rate may be calculated, an optical beam, such as produced by a laser, is passed through a fluid, transversely to a vortex street therein, and modulated in dependence on the alternate high and low velocity regions comprising the vortex street. The modulated signal is detected and 'cleaned' of noise by filtering with a first (high) band-pass filter of a center frequency f.sub.c, such that the first filter output comprises an amplitude modulated signal of carrier frequency f.sub.c modulated by the vortex shedding frequency, that is the frequency of oscillation of the power spectra between the respective curves for the high and low velocity regions. The first filter output is demodulated and filtered by a second (low) band-pass filter, whose output is of a frequency comprising the vortex shedding frequency.