Abstract
Flow velocity can be derived directly from the transit time of natural turbulence signals between two transducers spaced along the direction of flow. The transit time is determined by cross-correlating the transducer outputs with either a special purpose correlator or an on-line computer. Advantages are that the time delay can be measured absolutely by the correlator, the flowmeters are relatively insensitive to the effects of up-stream disturbances, the transducers do not obstruct the flow, and suspensions and slurries can be metered. Results are presented for flow measurement of sand/water slurries using electrical conductivity and ultrasonic transducers, and for heavily loaded gaseous suspensions using capacitance transducers.
A low cost mass flowmeter has been devised in which the mass flow of solids in a pneumatic conveyor is derived from measurement of variations in concentration intensity due to turbulence. Results are given for mass flow measurement of foodstuffs (flour, wheat and beans), pulverised fuel, cement and chemicals.
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