Patent ID: 8245581

Claim:
A flowmeter for detecting fluid flow rates in a pipe comprising: a tube having only a single channel with a constant diameter disposed in the pipe through which fluid in the pipe flows, the tube has a length L and a diameter opening D such that under volume flow conditions where Q>0.2 liters/hour, the tube dimensions L/D 2 are greater than 1385/meters when C>1400 m/s, the tube is made of a sound absorbing material that envelopes the channel, the tube forms a seal with the pipe essentially preventing fluid in the pipe leaking around the tube, the tube is made of a polymer filled with attenuative particles, the polymer is either an epoxy, nylon, PTFE or PEEK; an upstream ultrasonic transducer in contact with the pipe and positioned and positioned in alignment with the channel so plane waves having a transducer beam profile generated by the upstream transducer propagates through the channel; a downstream ultrasonic transducer in contact with the pipe and positioned in alignment with the channel so plane waves having a transducer beam profile generated by the downstream transducer propagate through the channel and are received by the upstream transducer which produces an upstream transducer signal, the downstream transducer receiving the plane waves from the upstream transducer and providing a downstream transducer signal, the upstream transducer and the downstream transducer extend through the pipe wall and acoustically communicate with the pipe interior; and a controller in communication with the upstream and downstream transducers which calculate fluid flow rate from the upstream transducer signal and the downstream transducer signal.