In stirred reactors, agitators are key for accelerating reactions, enhancing heat transfer and mixing. Selection depends on material properties and process needs.

Main Types

• Paddle agitators

Simple structure (flat/folded blades). Flat blades create tangential flow (better with baffles); folded blades have more axial flow. Diameter 1/2-4/5 of the container, 20-80r/min. For fluid circulation or medium-high viscosity materials, low cost but limited axial flow.

• Propeller agitators

Like marine propellers, high speed (7-15m/s tip speed), strong axial flow, large circulation but weak shear. Diameter 1/4-1/3 of the container. For low viscosity, large flow (e.g., liquid mixing, preventing sedimentation), better with draft tubes.

• Turbine agitators

Most used (open/disk types, flat/curved blades). 300-600r/min, balanced shear and circulation. Handles low-medium viscosity fluids, suitable for mixing, dispersion, heat transfer. Curved blades reduce power and protect fragile particles.

• Anchor/screw agitators

Anchor has diameter near container’s, low speed (0.5-1.5m/s tip speed), for fluids <100Pa·s (good for heat transfer, crystallization). Screw uses half the power of anchor, for high viscosity materials.

Selection & Accessories

• By viscosity

propeller → turbine → paddle → anchor → ribbon. By process: turbine for dispersion/heat transfer; propeller for large circulation; anchor for high-concentration slurries. CFD simulation optimizes efficiency.

Baffles (4-6, width 1/12-1/10 of container) convert tangential to axial/radial flow, enhance turbulence, replace some coils. Draft tubes limit circulation paths, boosting efficiency (often with propellers, with openings for liquid level changes).

Proper selection improves efficiency, cuts energy use, fitting various processes.