Viscometer is an instrument used to measure the viscosity of a fluid ( liquid or gas ). Viscosity is the physical quantity of internal friction occurring in the fluid when the fluid is flowing. It is the ability of the fluid to resist deformation and an important index used to identify some finished or semi-finished products. Viscosity varies with the type and temperature of the fluid. And what are the different types of viscometer? The following are seven common types which are widely used in petrochemical, pharmaceutical, food, light industry, textiles and other fields.