Method and apparatus for determining a change of the flow state of flowable substances from its static state to its flowing state or vice verse
US4112740A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 18, 1977 |
| Grant date | Sep 12, 1978 |
| Priority date | — |
| Expiry date | Jul 18, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/102
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for determining a change of the flow state of a flowable substance by transmitting ultrasonic or ultrasound waves of constant frequency to a spatial region of the substance, receiving ultrasonic waves backscattered by the substance, converting the backscattered ultrasonic waves into a primary signal which is amplitude- and phase-modulated in accordance with the backscattering and demodulating the primary signal in order to obtain a modulation signal. This modulation signal can be divided into a spectrum of signal components of different frequency and possessing pseudo periods which are defined as the time intervals between successive momentary values of the modulation signal, such momentary values corresponding to one another. The time duration corresponding to a predetermined number of pseudo periods is compared with a predetermined time duration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.