An instrument used for measuring the viscosity and flow properties of fluids. A commonly used type (Brookfield) measures the force required to rotate a disc or hollow cup immersed in the specimen fluid at a predetermined speed.
Of the many types, some employ rising bubbles, falling or rolling balls, and cups with orifices through which the fluid flows by gravity. Instruments for measuring flow properties of highly viscous fluids and molten polymers are more often called plastometers or rheometers. For other examples of viscometers, see alsoAIR BUBBLE VISCOMETER, CAPILLARY VISCOMETER, CAPILLARY RHEOMETER, EXTRUSION RHEOMETER, BRABENDER PLASTOGRAPH, FORD VISCOSITY CUPS, SHELL CUP VISCOMETER and ZAHN VISCOSITY cup. Also known as VISCOSIMETER, but viscometer is preferred.