Dual output vortex-shedding flowmeter having drag-actuated torsional sensor

A dual-output vortex-shedding flowmeter comprising:

• A. a flow tube through which a fluid stream to be metered is conducted, said tube having a longitudinal axis;
• B. a shedder having a predetermined geometry transversely disposed in said tube to divide the fluid stream therein and to cause vortices to be shed alternately on either edge thereof at a repetition rate proportional to the flow rate of the fluid, thereby producing downstream trains of vortices moving along the right and left sides of the tube;
• C. a torsionally-supported sensor disposed in said tube behind the shedder to define a gap therewith and provided with a pair of relatively broad parallel legs symmetrically disposed with respect to a spindle forming a central fulcrum axis which is normal to said tube axis, the opposite ends of the spindle extending outside of said tube, the divided fluid stream flowing past the shedder developing a torque about said fulcrum axis alternately in the clockwise and counterclockwise direction to cause the sensor to oscillate on the spindle at a frequency proportional to the flow rate of the fluid stream;
• and
• D. a pair of transducers operatively coupled to opposite ends of the spindle to produce two independent electrical signals whose frequency corresponds to the oscillating frequency of the sensor.