Agitators standard turbine design

It is important to note that the small-scale agitator operations may be described in terms of impeller diameter and agitator speed, while manufacturing process equipment is more conveniently specified by horsepower and fluid velocity. For most standard turbine configurations, power number correlations are available to convert impeller diameter and agitator speed into a horsepower value for given fluid properties. Most laboratory bench equipment is designed to provide a torque measurement that can be readily converted to horsepower directly from the conditions of the pilot batches. 

Studies on various turbine agitators have shown that geometrie ratios that vary from the standard design ean eause different effeets on the Power number Np in the turbulent regions [24]. 

Axial-flow impellers generate currents parallel to the axis of the impeller shaft. Radial-flow impellers generate currents in a direction tangential or radial to the axis of the impeller shaft. Within the two classes of impellers, there are three main types of impeller design. These are propeller, turbine, and paddle. The three main types are utilized in about 95% of most batch liquid agitation systems. Standard propellers have three blades, but two-bladed, four-bladed, or impellers encased by a circular guard can also be used. 

Variations of various geometric ratios from the standard design can have different effects on the power number Np in the turbulent region of the various turbine agitators as follows (B3). 

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