Patent ID: 7204129

Claim:
A method for determining a viscosity of a fluid within a container including the steps of: a) positioning the container between a pair of transducers; b) measuring a through-transmission time through the container and fluid between the transducers; c) measuring an outer echo transmission time of an outer echo signal from an outer surface of the container and an inner echo transmission time of an inner echo signal from an inner surface of the container; d) determining a time difference between the outer echo transmission time and the inner surface transmission time; e) determining a viscosity c b of the fluid based upon said steps b)–d) as: c b = ( t t b - h 1 + h 2 c m ⁢ t b - L - h 1 - h 2 c w ⁢ t b - 1 ) · c w where, L is a distance between the pair of transducers, c w and c m are sound velocities for water and a material of the container, h 1 and h 2 are the thicknesses of the container wall close to each of the pair of transducers, t is the through-transmission time, and t b is the traveling time of echoes between the two inner walls.