1. Augers, Hp & Adjustments
Lecture 18
Augers, Hp & Adjustments

2. Augers (screw augers) portable grain or wagons permanent (under bins)
 conveying feed (flexible)
 sweep augers
 stirring devices

3. 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

4. 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)

5. 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

6. Augers Tube & U trough augers Portable 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

7. 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 * 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)