When evaluating a paddle type mixer, you must prioritize motor power and torque, as these determine the mixer's ability to handle high-viscosity materials. Look for stainless steel construction (SUS304 or SUS316L) to ensure corrosion resistance and food/chemical grade safety. The paddle design (single or double shaft) should match your required mixing homogeneity; double-shaft paddles are superior for rapid, gravity-free mixing. Additionally, verify the sealing mechanism, such as mechanical or air-purge seals, to prevent powder leakage and cross-contamination.