Patent ID: 7637167

Claim:
An apparatus for determining at least one fluid property of a two phase fluid, the apparatus comprising: a conduit providing a fluid pathway for the two phase fluid; a restriction element operably disposed inside said conduit for restricting flow of the two phase fluid therethrough; means for measuring pressure of the two phase fluid downstream of the restriction element; means for measuring temperature of the two phase fluid flowing through said conduit downstream of the restriction element; means for measuring time of flight of sonic pulses within the two phase fluid flowing through said conduit downstream of the restriction element; resonator means for presenting a low acoustic impedance such that incident sonic pulses experience a phase inversion of one hundred-eighty degrees; means for calculating the speed of sound within the two phase fluid flowing through said conduit from the measured time of flight; and means for calculating at least one fluid property of the two phase fluid from the measured pressure, the measured temperature, and the calculated speed of sound.