A device is disclosed for measuring the mass and velocity of a fluid flowing in a conduit, in a flow direction, which comprises a pair of signal transducer arrays each disposed at planes extending through the conduit and spaced in the flow direction. Each transducer of each array is adapted to transmit...http://www.google.com.au/patents/US4462261?utm_source=gb-gplus-sharePatent US4462261 - Mass and velocity flowmeter
