Generally, pumps fall under two broad categories. The first category is centrifugal pumps, where the fluid is moved by rotating an impeller or propeller. The rotation, or centrifugal force, throws the fluid outwards generating the pressure to move the fluid through the piping system. The centrifugal pump is ideal for moving large volumes of low viscosity liquids. For high viscosity liquids, the ability of the centrifugal pump to throw the liquid decreases, affecting its performance. The maximum viscosity that a centrifugal pump can handle is dependent on the impeller design. We have successfully used centrifugal pumps for chemicals as high as 300 cP. Please contact us if you need assistance with your high viscosity applications.

Reference: https://www.pumpsandsystems.com/what-drag-effects-fluid-viscosity-centrifugal-pumps

The second category is positive displacement pumps. These pumps work by changing the volume of the chamber containing the liquid. One sub-category includes rotational pumps such as gears, lobes, or screws, where the meshing together and separation of the parts constantly change the chamber volume, displacing the liquid. Another sub-category works with pistons/plungers, such as piston pumps, plunger pumps, diaphragm pumps, and bellows pumps. One last sub-category involves a squeezing action like squeezing toothpaste, such as peristaltic pumps and tube pumps. Positive displacement pumps are ideal for highly viscous fluids.