HARVESTING AND THRESHING EQUIPMENT Flashcards
– process of gathering the useful portion of the crop from the field
Harvesting
process of separating the grains from the straw. Additionally, it may
include cleaning the grains
Threshing
Systems of harvesting and threshing of rice: _ _ use of hand tools: sickle, scythe, yatab, 80 – 160 man-hrs/ha
Manual harvesting
Systems of harvesting and threshing of rice: _ _Use of flails or sticks
* Hampasan
* Foot threshing
* Animal treading
* 140 – 220 man-hrs/ha
Manual threshing
Systems of harvesting and threshing of rice: _ _ Use of pedal thresher at 100 manhrs/ha
* Power thresher at 12 man-hrs/ha
Mechanized threshing
Systems of harvesting and threshing of rice: _ _ * Use of manually-operated
harvester at 50 man-hrs/ha
* Power harvester at 5 man-hrs/ha
Mechanical harvesting
- 3 – 21 man-hrs/ha
- Field losses – 1.5 – 6 %
Combine harvesting – both operations done by a single machine – combine
- 3 – 21 man-hrs/ha
- Field losses = 2 – 6 %
Stripping harvesting
removal of grains from panicle without cutting the
straw - stripper
Stripping harvesting
Systems of harvesting and threshing of rice: if manual harvesting manual threshing are combined, field loss is
5-16%
Systems of harvesting and threshing of rice: if manual harvesting and mechanized threshing are combined, field loss is
3-10%
Systems of harvesting and threshing of rice: if mechanical harvesting and mechanical threshing are combined, field loss is
3-6%
Operations done by a combine and stripper: . Separating the rows
2. Cutting the standing crop
3. Conveying the cut materials into the
threshing section
4. Threshing
5. Shaking the straw to separate loose grains
from the straw
6. Cleaning the grains of chaff
7. Conveying the grains to the tank or sack
COMBINE
Operations done by a combine and stripper: 1. Separating the rows
2. Stripping
3. Cleaning the grains
4. Conveying the grains to the tank or sacks
STRIPPER
Factors affecting the choice of system: IDENTIFY WHAT are INCLUDED
- Kind of crop
- Crop Color Preferences
- Timeliness of operation
- Topography
- Farm size
- Type of culture (row or broadcasted, upland or lowland)
- Moon phases
- Availability and cost of labor
- Required Labor inputs
- Availability of capital
- Kind of crop
- Timeliness of operation
- Topography
- Farm size
- Type of culture (row or broadcasted, upland or lowland)
- Availability and cost of labor
- Availability of capital
A major factor affecting choice of system is _ _ _ because it affects
field losses, time available for the next crop and grain quality
timeliness of operation
Field losses (%)
One week before maturity
0.77
Field losses (%)
At maturity
3.35
Field losses (%)
one week after maturity
5.63
Field losses (%)
two weeks after maturity
8.64
Field losses (%)
three weeks after maturity
40.70
Field losses (%)
four weeks after maturity
60.46
If the crop is harvested too early, it will have a large percentage of
imperfectly formed
kernels
The field should be drained _ _ weeks before harvesting to harden the soil
1 – 1.5 weeks
Harvesting equipment is classified into two categories: what are those?
Groupings of harvesting and Cutting mechanisms
Harvesting equipment (Groupings of harvesters) include the sickle, scythe, yatab, lingkao and cradle
Hand tools
Harvesting equipment (Groupings of harvesters)
– a machine that cuts the standing crop, conveys the cut
crop to one side, and lays them down in an orderly manner
Reapers-windrower
Harvesting equipment (Groupings of harvesters)
a machine that cuts the standing crop, binds the cut crop, and
lays down the bound crop to one side
Reaper-binder
Harvesting equipment (Cutting mechanisms)
– employed in hand tools
Slicing/tearing action
Harvesting equipment (Cutting mechanisms)
use of sharp or dull-edged blades
moving at high velocity of 2,000 fpm to 9,000 fpm
High velocity, single-element, impact action
Harvesting equipment (Cutting mechanisms)
shearing action between the moving and
stationary blades
Two-element, scissor type action
Threshing Equipment is classified into three categories, what are those?
Methods of threshing, mechanical threshers, and, cleaning systems
THRESHING EQUIPMENT:
* Methods of threshing: grains are detached from their panicles because of a rubbing action
as in treading by man, animal and vehicle.
Rubbing action
Output of man treading is
14 kg/hr
grains are accelerated faster than their panicles and are detached as
in hampasan and mechanical threshers.
Impact 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.
Stripping action
Output of hampasan is
It is one of the classifications of threshers equipment that employs the impact method
Mechanical threshers
Mechanical threshers are classified into 4:
Power source, type of feeding, direction of threshing materials, and type of cylinder teeth
Mechanical threshers classification that manual as in pedal thresher or power thresher as in
engine-driven thresher
power source
in type of feeding, – Straws do not pass through the threshing
section
hold-on feeding
in type of feeding that has ❖ Low power requirement
❖ Lightweight construction
❖ Examples: Pedal thresher and Japanese combine
hold-on feeding
in type of feeding it Straws pass through the threshing section
Throw-in feeding
❖ High power requirement
❖ Heavyweight construction
❖ Examples: Axial-flow thresher and US combine
Throw-in feeding
Materials are feed between the revolving
cylinder and stationary concave and go straight out of the
thresher tangentially.
Tangential-flow
About _% of the grains pass through the concave and
the rest are separated in subsequent operations.
60%
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.
Axial-flow
About _% of the grains are separated from the straw
at the cylinder.
90%
type of cylinder teeth are:
a. Wire-loop
b. Peg-tooth
c. Rasp-bar
Separation of the bulky straw, chaff, empty kernels and very light impurities from the
grains
Cleaning systems
Light materials can be separated from the grains by
winnowing using natural wind or
blower.
straws do not pass through the thresher and only the removal
of the chaff and light materials are needed using blowers and screens
For hold-on threshers,
straws pass through the thresher and cleaning is done using a
straw walker, blower and screens.
For throw-in threshers,
