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Lecture 18. Augers, Hp & Adjustments. Augers (screw augers) . portable grain or wagons permanent (under bins) conveying feed (flexible) sweep augers stirring devices . Theoretical capacity. CFTHR = (D2 - d2) * P * RPM 36.6
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Lecture 18 Augers, Hp & Adjustments
Augers (screw augers) • portable • grain or wagons • permanent (under bins) • conveying feed (flexible) • sweep augers • stirring devices
Theoretical capacity CFTHR = (D2 - d2) * P * RPM 36.6 CFTHR = cubic feet / hour material moved D = diameter of screw, inches d = diameter of shaft, inches P = pitch of auger, inches (usually = to D) RPM = revolutions per minute of shaft. Note- actual capacity is usually 1/3 to ½ the theoretical capacity
Horsepower CHP = C * L * W * F 33,000 CHP = computed horsepower C = conveyer capacity, (ft3 / min L = length of conveyer (ft) W = Bulk weight of material (lb/ft3) F = material factor (table 6.1)
Adjustments to horsepower if CHP < 1, HP = 2.0 * CHP if 1<=CHP <2, HP = 1.5 * CHP if 2<=CHP <4, HP = 1.25 * CHP if 4<=CHP <5, HP = 1.1 * CHP if CHP >5, HP =1.0 * CHP
Augers • Tube & U trough augers • Most common, U trough operates at slower speeds than tube augers. • U-trough = less damage to your grain • tube augers are less expensive • Portable augers • Diameters = 6" to 12" • Length = 27' to 81' • 45 degree or less is practical
Formulas to calculate auger length needed... if the auger angles greater than bin roof slope: L = BEHGT + (.05 * BND) SIN (t) COS (t) If auger angles less than or equal to bin roof slope: L = BEHGT + .05 * BND * TAN (r) SIN (t) L = length of auger BEHGT = eave height of bin (ft) BND = bin diameter (ft) t = angle of auger relative to ground (degrees) r = slope of bin roof (degrees)