Abstract: A method and systems based thereon for conducting a multiple velocity traverse of a flow stream cross section of known shape and area to determine flow therethrough. The technique employs any one of the known methods of numeral integration to place the traverse chords and weight the chord average velocities, the technique being applicable to flow streams of any known cross-sectional shape and area without requiring that the chords be parallel.

Abstract: A flowmeter capable of accurately measuring and transmitting extremely low flow rates, the meter including a vertically-positioned flow tube having a ferromagnetic ball therein which is subjected to the force of gravity as well as to the drag force imposed by the upward flow of fluid to be metered. Associated with the flow tube is a position sensor which yields a control signal when the ball lies in a detection zone. The ball is also subjected to a magnetic force produced by an electromagnet energized by a current controller governed by the control signal, which force seeks to displace the ball away from the detection zone. The control signal causes the magnet current to pulse and the ball to oscillate in said tube at a frequency which is a function of flow rate, the frequency of the current being indicated to provide a flow rate reading.

Abstract: A flowmeter capable of accurately measuring and transmitting extremely low flow rates, the meter including a vertically-positioned flow tube having a ferromagnetic ball therein which is subjected to the force of gravity as well as to the drag force imposed by the flow of fluid to be metered. Associated with the flow tube is a position sensor typically constituted by a light source projecting a beam across the translucent tube that is intercepted by a photosensor yielding a control signal when the beam is obscured by the ball. The ball is also subjected to a magnetic force produced by an electromagnet energized by a current controller governed by the control signal, which force seeks to displace the ball away from the light beam. Thus the ball acts as a force summing junction and is caused to assume a position depending on the vector resultant of the co-acting drag, gravitational and magnetic forces.