Patent ID: 7228728

Claim:
A device for determining the rheological parameters of a flowing fluid, wherein the device comprises: at least one wall area that contacts and borders a fluid flowing in the device at least in partial areas of the fluid interface; an ultrasound transmitter for sending an ultrasound signal with at least one preset frequency f 1 at an angle θ relative to the direction of flow of a fluid flowing in the device, said angle θ being different from 90°; an ultrasound receiver for receiving an ultrasound signal with at least one frequency f 2 that can be shifted relative to frequency f 1 by a frequency shift Δf; at least one shear stress sensor for detecting a wall shear stress in at least one area of the fluid in contact with the wall; one computer and processor for calculating frequency differences and allocating a specific frequency difference to a respective fluid area using a respective time difference between the transmission and reception of an ultrasound signal; for calculating the fluid velocity of a respective fluid area using the respective frequency shift; and for calculating rheological parameters of the fluid using the acquired wall shear stress of the fluid and the calculated fluid velocity of the respective fluid areas of the flowing fluid.