With three types of impellers Aipu mud agitators are available and are sized according to tank volume and expected duty. Active mud system compartments (such as solids removal sections, mud mixing sections and slug pits) need a higher shear blade to produce more immediate mixing. Bulk storage compartments need a low-shear blade that maintains suspension in a gentler manner.
When compartment height is greater than 1.52m (5 ft) either a 60-degree canted impeller, or a high volume contour blade is used to encourage axial as well as radial flow. For tanks deeper than 3.66 m (12 ft), two or more impeller blades may be employed in combination.
For bulk storage tanks, high-efficiency, contour impellers are best. This variable pitch impeller reduces horsepower requirements and induces less shear in the mud.
Aipu mud agitators are sized according to the duty. Proper sizing is determined by calculating the Turn Over Rate (TOR) for each agitated compartment. TOR is the right time required, in seconds, to completely move the fluid in a mud tank. For 60-degree canted blade applications TOR should be between 40 and 90 seconds. When the TOR approaches 40 seconds, the chance for air entrainment increases. At TOR greater than 90, proper suspension may be jeopardized and solids will really start to settle. For contour blade applications, TOR must be significantly faster to achieve the same results, but because of the 100% axial flow, air entrainment is not an issue.
TOR = Vt/D×60 Vt = Tank volume in gallons (L×W×H×7.48) D = Impeller displacement in GPM