The Fann viscometer is a type of viscometer used to measure the viscosity of a liquid or a gas. It is used in a wide variety of industrial applications, such as oil and gas, paints and coatings, food and beverage, and pharmaceuticals. The Fann viscometer is a shear-type viscometer, meaning that it measures the viscosity of a material by applying a shearing force to the sample. The viscosity is then measured by the rate at which the sample deforms under this shearing force. The Fann viscometer is typically used to measure the viscosity of Newtonian fluids, which are fluids that exhibit a linear relationship between shear stress and shear rate.