The document provides information about combine harvesters. It discusses that combine harvesters are machines that harvest, thresh, and clean grains from straw in a single operation. They can be tractor pulled or self-propelled. The main components of a combine harvester include the cutting unit, threshing unit, separating unit, cleaning unit, and grain and straw handling units. It works by cutting crops, threshing them, separating the husk from grains, cleaning the grains, and storing them. The document also lists the requirements for an effective combine harvester.

1. Combine Harvester(CH)
Prepared by
Er.Uttam Raj Timilsina(MSc.Engineering,IIT
Roorkee)
Professor of Agricultural Engineering,AFU
uttamrajtimilsina@gmail.com, 9841684994
For
Batch 2069/2070,BSc.Ag,4th semester(071/7/16-
071/10/15)
Course Code:AEN-301,Farm Power and
achinery(1+1

2. Components and Working Principle
• Combine Harvesters:-These are the machines used for
harvesting,threshing,cleaning the grains from straw in a single
operation. These can be pulled and operated by tractor as well
as self propelled combine machines are available .The suitable
working speed of combine harvester is o.8-8km/hr for rice and
2-6 km/hr for wheat with the reel speed of 1.25-1.5 times
greater than working speed. The cutting width or capacity of
tractor drawn combine varies as 1.25-2.5 meter in smaller
combine and 3-6 meter in bigger combine with the power
requirement of 10 hp/meter of cutting width.The self propelled
combines are the latest model with the power of 60-150 hp and
cutting width of 2-7 meter.The combine harvester consists of
cutting or harvesting unit,threshing unit,seperating unit,cleaning
unit ,grain handling /storage unit,and straw handling unit.The
power requirement per meter of cutting width in self propelled
combine is about 15 hp/meter.

3. CH
• Function of combine harvester-
Feeding the standing crops to the cutter bar with
the help of reel
Cutting the crop(harvesting)
Feeding the crop to threshing unit
Threshing the crop
Separating the husk from grains
Cleaning the grains
Conveying and storing the grains

4. CH
• Requirement of a perfect Combine Harvester-:
 There should be less broken of grains
 No grains losses on the ground at the cutter bar end
 No grain losses at the back end of the harvesting unit
 No unthrashed grain
 Proper threshing of grains without any injury
 It should give clean grains
 Machine should be capable of operation on crop even with higher
moisture content
 Machine should be capable of working on various crops
 Ease of operation
 More output with safety measures
 Easy to maintain
 Less consumption of spares and fuels

5. CH
• Type of combine harvester(CH)
 Pull type or tractor mounted/drawn CH-These are of two size
smaller and bigger with the cutting width(capacity) of 1.25-2.5
meter and 3-6 meter with the power requirement of about 10
hp/meter of cutting width
 Pull type or tractor drawn with auxiliary engine CH:-These are the
machines ground speed is covered tractor and working power is
covered by auxiliary engine
 Self propelled combine harvester(CH):-These are the latest model
with the power of 60-150 Hp and cutting width of 1.5-2
meter(smaller) and 2-7 meter(bigger).The power requirement per
meter cutting width is about 15 Hp/meter.The suitable working
speed in field is 2-6 km/hr and in road is 4-20 km/hr.

6. Tractor mounted CH

7. Tractor mounted CH

8. Self propelled CH

9. Self propelled CH

10. Self propelled

11. Self propelled CH

12. Rice CH

13. Rice CH

16. Main parts of Combine
Harvester(CH)
Reel
Cutter bar with automatic cutting height
adjuster( censer type)
Auger
Elavator to threshing cylinder
Stone trap
Threshing cylinder with front beater
Rear beater
Perforated friction deviced concave
Main grain pan of oscillating type
Oscillating sieves more than one
Air blower with fan
Grain elevator to tank
Unloading auger
Grain tank
Straw walker
Grain loss monitor
Pan under walker

24. • Cutting,threshing,cleaning mechanism of a combine harvester:-
The standing crop is guided to the cutter bar by the help of reel and dividers.
The reel diameter is 1-1.5 m.The clearance between cutter bar and bottom
of reel is 12.5-25cm and adjustable. The cutter bar with serrated knives to
cut the crop is placed 7.5-90 cm above the ground level and adjustable.The
crop is cut by the action of cutter knives and the cut crop is accumulated by
auger and send to thresher cylinder through elevator .Threshing takes
places between threshing drum and concave at a speed of 2000-7000 rpm.
.The threshing clearance between drum and concave at front is 19-13mm
and at rear is 9-6mm as at the ratio of 2.5:1.After threshing the threshed
materials like straw or chaff pass on to the shakers type straw walker while
mixture of grains and chaff pass to the series of shaker sieves where wind
blower blows the chaff out of the machine and cleaned grains are collected
to the returned pan and is send to grains tank by the help of grain auger
and elevator.Pieces of unthreshed heads are subjected to pass to the main
threshing drum for re-threshing or some small re-thresher devices .The
losses crop ,grains and all the problems of machine parts is monitored by
grain loss monitor.