Patent ID: 6973842

Claim:
A volumetric flow sensor for measuring a volumetric flow rate of a fluid flowing in a pipe, the sensor comprising: a probe insertable into the pipe to a selected insertion depth therein, the probe comprising: a flow velocity detector for supplying a raw flow signal responsive to a component of the fluid flow in a selected flow measurement direction defined with respect to an axis of the probe; and a pipe size detector for supplying a electrical transit time signal, the pipe size detector comprising at least one acoustic transducer disposed on the probe for projecting an acoustic beam in a direction perpendicular to the flow measurement direction and for detecting a portion of the beam reflected from at least three different locations on an internal surface of the pipe; a size signal circuit for processing the transit time signal from the pipe size detector and for generating therefrom a size signal output representative of an inside diameter of the pipe; and a flow measurement circuit operable to receive the size signal output and the raw electrical flow signal and to calculate therefrom the volumetric flow rate.