Anchor mixers are commonly used for mixing of viscous liquids with a viscosity range between 5000 and 50,000 cps. The sweep diameter of the anchor impellers is 90 to 95 percent of the vessel diameter, and therefore the clearance between the impeller and the internal wall is minimal. Anchor type impellers are preferred when heat transfer is desired along with good mixing. The shear near the vessel wall reduces the buildup of stagnant material, and promotes heat transfer. Scrapers or wipers can be provided remove material deposited on internal walls of the vessel, further enhancing the transfer of heat. Anchors are commonly used in crystallization reactors.

Due to the limitations of the anchor impeller to provide top-bottom fluid motion, anchors can be used in conjunction with axial flow impellers. Anchor impellers can also be used in combination with high shear impellers.

Anchor type impeller