Double wing vortex flowmeter with strouhal number corrector
AssigneeBadger Meter, Inc.
InventorWilliam H. Vander Heyden
Life of this patent
Estimating the term…
Abstract
A vortex flowmeter includes a body having a flow passage, a vortex generator that generates a standing transverse wave in the flow passage, and first wing and second wings in the passage downstream of the generator. A circuit that utilizes sensors in the two wings is provided for first determining an operational phase difference, .DELTA..phi..sub.m between the signals representing movement of the first and second wings. A microprocessor then determines a corrected vortex frequency, .sup.f corr, in response to a ratio of a predetermined calibration phase difference .DELTA..phi..sub.c to the measured phase difference .DELTA..phi..sub.m.
Claims10
A vortex flowmeter comprising:
- a body having a passage for flow of a fluid therethrough in a longitudinal direction;
- a vortex generator positioned in the passage for transmitting vortices downstream;
- a first vortex sensor located at a first sensor position downstream of the vortex generator, the first vortex sensor producing a first signal of the vortex frequency, f.sub.m, in response to passage of vortices through the first sensor position;
- a second vortex sensor located at a second sensor position downstream of the vortex generator, the second vortex sensor producing a second signal of the vortex frequency, f.sub.m, in response to passage of vortices through the second sensor position, said second signal being phase delayed from said first signal;
- means for determining a measured phase difference .DELTA..phi..sub.m between the first signal and the second signal;
- and
- means for comparing the measured phase difference .DELTA..phi..sub.m to a calibration phase difference .DELTA..phi..sub.c representing the phase difference between the first sensor position and the second sensor position wing under pre-operational, calibration conditions;
- means for determining a corrected vortex frequency, f.sub.corr, of said flow meter during operation in response to a ratio of the predetermined calibration phase difference .DELTA..phi..sub.c to the measured phase difference .DELTA..phi..sub.m.
A method of determining a fluid velocity V.sub.m of fluid flowing through a flow passage comprising:
- using a vortex generator with a characteristic dimension D to generate rows of vortices in the flow passage to form a standing transverse wave flow pattern;
- detecting the vortices at one position in the flow passage;
- detecting the vortices at a second position in the flow passage located downstream from the first position;
- producing a first signal of a vortex frequency, f.sub.m, in response to detecting the vortices at the first detection position;
- producing a second signal of a vortex frequency, f.sub.m, in response to detecting the vortices at the second detection position;
- determining a phase difference .DELTA..phi..sub.m between the first and second signals;
- determining measured fluid velocity V.sub.m by obtaining a corrected vortex frequency, f.sub.corr, by multiplying the vortex frequency, f.sub.m, by the ratio of the predetermined calibration phase difference .DELTA..phi..sub.c to the measured phase difference .DELTA..phi..sub.m.
Dependencies are inferred from the claim text.