Abstract:
Various methods of harvesting grains, type of grain losses and how to minimize
them are discussed.
The header unit of a tractor-driven combine harvester was designed,
fabricated and tested. The unit consists principally of the stripping rotor which derives its
peripheral speed from the tractor Power-Take-Off Shaft (p.T.O.)
The power requirement
was found to be 4.03 kw and stripper theoretical capacity 0.21 kg/so Stripper shaft diameter
was calculated after determining the vertical and horizontal forces that acted on it. Pulleys
and belts to transmit the calculated speed ratios were selected. Suitable materials were
selected for the components of the machine and the cost of producing the machine was
M22,384:27. The machine was tested at five peripheral speeds of 100, 140, 180, 220 and
260 rev/min at two forward speeds of3 krn/hr and 5 km/hr, A 60 kw Ford tractor was used
for the test.
Results showed that header total losses reduced with increasing peripheral
speed with the highest reduction occuring between 100 rev/min and 140 rev/min for the two
forward speeds. Machine field efficiency also increased linearly from 69.1 % at 100 rev/min
to 92.0% at260 rev/min and from 77.7%.to 90.2% at 3 krn/hr and 5 kmIhr respectively.
Regression equations were obtained for shatter, unstripped and total header losses which
r
could be used to determine the losses at different peripheral speeds. The machine is easy to disassemble for maintenance.
