Machinery module

1. HARVESTING AND
THRESHING MACHINERY

2. Identity various harvesting and threshing
machinery;
Operate and evaluate the performance of
harvesting and threshing machinery.
OBJECTIVES:

3. HARVESTIN
G
It is the operation of cutting, picking,
plucking, digging or a combination of
these operations in removing the crop
from under the ground to separate the
plant’s useful parts.

4. THRESHIN
G
It is the process of detaching grains
from the straw.
Additionally, it may include cleaning
the grains.

5. SYSTEM OF HARVESTING AND
THRESHING

6. HARVESTING
1. Traditional System
2. Conventional System

7. Harvesting is done using mechanical reapers, reaper-binders and
reaper
windrowers.
Harvesters may be categorized into manually operated and power
harvesters.
Manually-operated harvesters requires about 50 man-hours per
hectare
Power harvesters requires 5 man-hours.
About 3% to 6% field losses
HARVESTING
3. Mechanical System

9. HARVESTING
4. Combine Harvester
single machine called combine performs
harvesting and threshing while on the go
Using a combine harvester may reduce field
losses to about 1.5% to 6%, requiring only
about 3-21 man-hours per hectare of field

10. HARVESTING
5. Stripping
This method is also called in-field threshing or
simply stripping and is performed by a
machine called stripper
The panicle is made to pass between two bars
of “V” configuration to separate the grain from
the straw.
Most strippers are equipped with tanks to
temporarily store the harvested grains, or
contain mechanisms to transfer the grains into
sacks
Reduce field losses to about 2% to 6%

11. THRESHING
1. Traditional System

12. Done using mechanical threshers
Mechanical threshers reduces the labor requirement to about 100 man-
hours-pedal threshers while 12 man-hours per hectare for power
threshers
Cleaning grains by winnowing or manually operated winnowers
Power threshers with built-in blowers and oscillating screens
Reduces the field losses to about 3% to 10%
THRESHING
2. Conventional System
3. Mechanical
System

13. THRESHING
4. Combine Harvester
single machine called combine performs
harvesting and threshing while on the go
Using a combine harvester may reduce field
losses to about 1.5% to 6%, requiring only
about 3-21 man-hours per hectare of field

14. THRESHING
5. Stripping
This method is also called in-field threshing or
simply stripping and is performed by a
machine called stripper
The panicle is made to pass between two bars
of “V” configuration to separate the grain from
the straw.
Most strippers are equipped with tanks to
temporarily store the harvested grains, or
contain mechanisms to transfer the grains into
sacks

19. FACTORS AFFECTING
CHOICE OF SYSTEM:
• Kind of crop
• Timeliness of
operation
• Topography
• Farm size
• Type of culture (row
or
broadcasted,
upland or lowland)
• Availability and cost
of labor

20. FACTORS AFFECTING CHOICE OF
SYSTEM
A major factor affecting choice of system is timeliness of operation because
it affects field losses, time available for the next crop and grain quality
If the crop is harvested too early, it will have a large
percentage of imperfectly formed kernels.
The field should be drained 1 – 1.5 weeks before harvesting to
harden the soil

21. CUTTING MECHANISMS FOR
HARVESTERS
1. Slicing/tearing
action – employed
in hand tools

22. CUTTING MECHANISMS FOR
HARVESTERS
2. High velocity,
single-element,
impact action
– use of sharp or dull
edged blades moving
at high velocity of
2,000 fpm to 9,000 fpm

23. CUTTING MECHANISMS FOR
HARVESTERS
3. Two-element,
scissor type action
– shearing action
between the
moving and stationary
blades

24. THRESHING MACHINERY
1. Rubbing action – grains are detached from their panicles
because of a rubbing action as in treading by man, animal and
vehicle.
• Output of man treading is 14 kg/hr
2. Impact action – grains are accelerated faster than their panicles
and are detached as in hampasan and mechanical threshers.
• Output of hampasan is 34 kg/hr
• Output of mechanical threshers vary with size of machine and
power source.
3. Stripping action – grains are detached from their panicles when
the straw is pulled through a “V” configuration or a comb-like
device is passed through the panicles.

25. MECHANICAL THRESHERS
Mechanical Threshers Mechanical threshers are machines that separate the grains
from the panicles. This function is achieved by employing impact action. In addition to
this primary function, modern threshers also perform the following tasks:
1. Feed the un-threshed grain to the threshing cylinder in an even stream, free from heavy,
solid bunches (Feeding Unit)
2. Separate the straw from the grain and chaff, and separate the chaff and dirt from the grain
(Cleaning Unit)
3. Deliver the straw through the stacker to the stack and deliver the grain through the grain
elevator, weigher or stacker to wagon or bin (Stacking and Storage Unit)

26. Variability of threshers come from:
1. Power source – manual as in
pedal thresher or power thresher
as in engine-driven thresher
(Figure 8 and 9)

27. Variability of threshers come from:
2. Type of feeding:
a. Hold-on feeding – Straws do
not pass through the threshing
section (Figure 10).
• Low power requirement
• Lightweight construction
• Examples: Pedal thresher
and Japanese combine

28. Variability of threshers come from:
2. Type of feeding:
b. Throw-in feeding – Straws pass
through the threshing section
(Figure 11).
• High power requirement
• Heavyweight construction
• Examples: Axial-flow thresher
and US combine

29. Variability of threshers come from:
3. Direction of threshing materials (Figure 12):
a. Tangential-flow – Materials are feed between the
revolving cylinder and stationary concave and go
straight out of the thresher tangentially.
• About 60% of the grains pass through the
concave and the rest are separated in
subsequent operations.
b. Axial-flow – Materials are fed between the
revolving cylinder and stationary concave on one
end, go around the cylinder several times axially
and discharge at the other end.
• About 90% of the grains are separated from the
straw at the cylinder.

30. Variability of threshers come from:
4. Types of cylinder teeth
(Figure 13):
a. Wire-loop
b. Peg-tooth
c. Rasp-bar

32. Sample problem
1: A 5-m self-propelled combine makes an average stop of 4
minutes everytime its 2-ton grain tank is to be unloaded.
The yield of the 20-ha field is 40 tons. The operating speed
is 4.8 kph. The time for turning on the headland at the ends
of the 500-m field is 15 seconds. Find: a. theoretical field
capacity b. actual field capacity c. Field efficiency