Construction and Performance Evaluation of a High Pressure Falling Sphere Viscometer

A falling sphere viscometer, which is capable of absolute measurements of the viscosity of reference liquids at pressures up to 500MPa with an error less than ±0.5%, has been designed and constructed. The falling-time of sphere can be measured automatically using two laser beams through the windows on the high pressure vessel of the viscometer. The sphere is returned to its starting position by rotation of the high pressure vessel.This paper describes the construction and the principle of operation of the falling sphere viscometer. The results of evaluation of the viscometer's performance obtained by measurement of the viscosities of reference liquids, namely the Standard Liquids for Calibrating Viscometers, are also described.