Inventors:
J. Vincent Fitzgerald - Metuchen NJ
Frank J. Matusik - Piscataway NJ
Donald W. Nelson - Voorhees NJ
Assignee:
National Metal and Refining Company, Ltd. - Edison NJ
International Classification:
G01N 1114
Abstract:
A rotary viscometer of the type which measures the viscous torque to which a rotating spindle is subjected, by measuring the current drawn by the electric motor driving the spindle. True viscosity, i. e. the slope of the torque-spindle rotation speed curve, is approximated by varying the spindle speed stepwise in sets of speed measurements having a fixed speed difference, and obtaining the difference between the corresponding torque values for each set. By repeating this process throughout the desired speed range, an approximate derivative of the torque-speed curve is obtained, corresponding to an approximation of the true viscosity of the fluid being characterized.