The Design Process for Laboratory Overhead Stirrers

　　2. Calculate mixing power: the power required by the stirring process.

　　Reference formula: power = power number × liquid density × rotational speed to the power of 3 × impeller diameter to the power of 5.

　　Calculating the power number is complex and depends on tank diameter, impeller diameter, blade width, blade angle, number of impeller stages, viscosity, and baffle number and dimensions.

　　3. Select motor power: after accounting for efficiency, the calculated value should be at least 1.5 times the mixing power.

　　4. Determine the minimum required stirring speed. This is the lowest speed that achieves the mixing objective, not the shaft's critical speed.

　　5. Select and check the shaft and impeller stiffness and strength based on power.

　　6. If using a reducer, consider its service factor and load capacity.

　　7. Slender shafts may need intermediate or bottom support.

　　8. Consider mounting type—top, bottom or side entry—which should be established first.

　　9. Design the support.

　　10. Select the seal type: packing or mechanical seal.