The viscometer is an instrument used in the petrochemical industry to measure the viscosity of a liquid solution. This information is used to calculate fluid parameters, such as current intensity, pressure drop, temperature, etc. This information is important for determining the behavior of fluids in a mechanical system. The measurement made with a viscometer must be accurate and reliable, so that the decisions made on that measurement are correct.

In general, the viscometer uses a viscosity indicator to measure the viscosity of a fluid flow. The equipment is equipped with a rotating shaft on which one or more viscosity tests are placed. The measurement is typically performed in units of poise. The basic principle of operation of a viscometer is based on the viscosity law of fluids. This law states that the tangential force required to move a fluid through a steady state depends on the resistance to flow at a constant area.