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:
Oct. 06, 1992
Filed:
Sep. 24, 1990
Edward V LaBudde, Westlake Village, CA (US);
Other;
Abstract
An acoustic signal is transmitted into a flowing gas (10). The velocities of propagation of the signal in two predetermined directions are measured, and combined with sensed gas pressure and the frequency of the acoustic signal to compute the mass flow rate of the gas. The velocities are preferably measured as analogous phase differences between the transmitted signal, and the signal as incident upon receivers (18,20) spaced from the signal transmitter (16) by predetermined distances in the predetermined directions. The phase differences are preferably sensed using at least one phase locked loop (44) which adjusts the signal frequency so that a predetermined phase difference is maintained between the transmitted signal and one of the received signals or a derivative thereof. The flow rate computation includes obtaining the speed of the acoustic signal (speed of sound) in the material and the velocity of movement of the gas from the sensed phase differences. The sensor may also be used to sense the velocity of movement of a liquid or solid, in which case the pressure measurement is unnecessary. The velocities may alternatively be measured as propagation times or wavelength shifts, rather than as phase differences. In addition, the temperature of the flow of a gas may be obtained by the same apparatus.