Viscosity refers to the resistance of fluid to flow, which is defined as: when the liquid flows at the speed of 1cm / s, the required shear stress on each 1cm2 plane is called dynamic viscosity, and the unit is pa ÷ s.

Viscosity is an attribute of a fluid. When the fluid flows in the pipeline, there are three states: laminar flow, transitional flow and turbulent flow. There are also three states in the mixing equipment, and one of the main parameters determining these States is the viscosity of the fluid.

In the mixing process, it is generally considered that the viscosity is less than 5Pa s, such as low viscosity fluid, such as water, castor oil, maltose, jam, honey, lube heavy oil, low viscosity emulsion, etc. 5-50Pa s is a medium viscosity fluid, such as ink, toothpaste, etc. 50-500Pa, s is highly viscous fluid, such as chewing gum, plasticizing sol, solid fuel, etc. it is super high viscosity than 500Pa s. Fluids such as: rubber mixture, plastic melt, silicone, etc.

For low viscosity media, a small-diameter high-speed mixer can drive the surrounding fluid circulation to a distance. But the high viscosity medium fluid is otherwise, needs to use the agitator to push directly.

The impellers suitable for low viscosity and medium viscosity fluid are paddle type, open turbine type, propulsion type, long thin blade propeller type, disc turbine type, Brumajin type, plate frame propeller type, three blade backward bending type, MIG type, etc. The impellers suitable for high viscosity and ultra-high viscosity fluids are screw belt impellers, screw type impellers, anchor type impellers, frame type impellers, propeller type impellers, etc. Some fluid viscosities change with the reaction, so it is necessary to use impellers suitable for wide viscosity field, such as pan energy impellers.