US Patent 7201040 Rheometer with axial resistive force measurement

A rheometer comprises a vessel mounted on a stand and a rotatable blade mounted above the vessel. A substance for rheometric assessment is put in the vessel. The rotor is advanced linearly into the substance while at the same time rotating. The blade is arranged with a profile such that there is substantially zero slip as it progresses, thereby minimising disturbance to the substance. The rheometric assessment is based on the axial force exerted as a result of the resistance of the substance to the progression of the blade through it.