Patent ID: 8291773

Claim:
An ultrasonic measurement device ( 10 ) for determining a flow velocity of a fluid in a conduit, comprising: a pipe section ( 12 ) having a central longitudinal axis ( 22 ) and a cross section ( 24 ) with a radius (R), the central longitudinal axis ( 22 ) defining a horizontal reference plane ( 26 ); a two-path measurement system comprising a first path ( 30 a ) and a second path ( 30 b ) defined by a first pair of ultrasonic transducers ( 32 ) and a second pair of ultrasonic transducers ( 32 ) mounted to the wall of the pipe section ( 12 ), the ultrasonic transducers ( 32 ) of each path ( 30 a - b ) opposing each other at the ends of their path ( 30 a - b ), each path ( 30 a - b ) oriented parallel to the horizontal reference plane ( 26 ) with a distance to the horizontal reference plane ( 26 ) while having a component transverse to the central 15 longitudinal axis ( 22 ); first evaluation means ( 38 ) to determine a first flow velocity value from the first path ( 30 a ) by comparing the ultrasonic transit times along the first path ( 30 a ) with and against the fluid flow and a second flow velocity value from the second path ( 30 b ) by comparing the ultrasonic transit times along the 20 second path ( 30 b ) with and against the fluid flow; and first integration means ( 40 ) to determine the flow velocity from the first flow velocity value and the second flow velocity value, wherein the distance from the paths ( 30 a - b ) to the horizontal reference plane ( 26 ) is greater than half the radius (R).