THRESHER TESTING PROCEDURE IN DETAIL

1. TOPIC – TESTING OF
TRHESHER
PRESENTED BY
GEETA PATEL

2. THRESHING
• Threshing is the process of loosening the edible
part of cereal grain (or other crop) from the
scaly, inedible chaff that surrounds it.
PRINCIPLE OF WORKING
• Threshing can be achieved by three methods
i. e.— rubbing,— impact and— stripping.

3. TYPES OF THRESHING CYLENDER

4. DIFFERENT COMPONENT OF
MULTIFUNCTION THRESHER

5. BASIC THRESHIN OPERATION

6.  Power thresher : A machine operated by a prime mower to separate the
grains from straw
 Clean grain : Threshed, mature, unbroken grain and free from foreign matter
 Damaged grain : Threshed grain which is partially or wholly broken
 Un threshed grains : Whole grain attached to straw after threshing
 Chaffed straw : Straw being discharged from threshing chamber which is
usually crushed cut
 Foreign material : Inorganic and organic material other than grain which
includes sand, gravel, clay, metal chip, chaff and straw, weed and other inedible
grains.
 Grain straw ratio: Ratio of grain to straw by weight
 Maximum input capacity : The maximum feed rate at which no chocking
occurs in the thresher and no stalling occurs in the prime mower at the speed
specified by the manufacturer.
 Optimal input capacity: The feed rate at which efficiencies are within the
specified limits of the relevant Indian standards
 Output capacity: The mass of the grain mixture received at main grain outlets
when collected at optimal input : the mass of grain mixture per horsepower per
hour
TERMINOLOGY

7.  Percentage of blown grain: The clean grain lost along with chaffed straw
with respect to total grain input expressed as percentage by mass
 Percentage of broken grains : The broken grains from main grain outlets
with respect to total grain mixture received at main grain outlets expressed
as percentage by mass
 Percentage of spilled grain : The clean grain dropped through the sieve
and over flown from sieve along with tailings with respect to total grain
input, expressed as percentage by mass
 Percentage of un threshed grains : The un threshed grain from all outlets
with respect to total grain input, expressed as expressed as percentage by
mass.
 Threshing efficiency : Threshed grains obtained from all outlets with
respect to total grain input expressed as percentage by mass
 Transporting weight: The weight of thresher when transported
 Specified weight: The range of rotational speed of threshing drum shaft
when threshing wheat
 Specific thresher output: The mass of grain mixture per horsepower per
hour

8. Type of Test
Power threshers for testing are normally
selected at random from the series
production by a representative of the
testing organization.
The method of selection should be
specified in the test report.
The following tests are conducted for
thresher
A. General Test.
1. Checking of specification
2. Checking of material
3. Checking of safety provisions
4. Visual observation and adjustment
B. Test at No Load
1. Power consumption
2. Visual observation
C. Test at Load
1 Short run
a) Quality of work
i. Losses
ii. Percentage of broken grain
iii. Percentage of blown
iv. Percentage of unthreshed grain
v. Percentage of spilled grain
b. Efficiency
i. Threshing
ii. Cleaning
c) Power consumption
d) Capacity
i. Rated input capacity
ii. Output capacity
iii. Corrected output capacity
e) Visual observations
2 Long run
1. Effect on performance at
recommended speed over a long
period of use
2. Convenience of handling including
transport
3. General durability

10. TEST AT NO-LOAD
1.Power Consumption
• Install the thresher on level preferably on a hard surface and
set the clearance, screen slope, etc, in accordance with
manufacturer's recommendations. Use electric motor of
appropriate power, fitted with an energy meter for running the
thresher. The manufacturer shall declare the crop wise speed of
operation in their recommendations.
• Run the thresher at no-load for at least 10 minutes at the
specified revolution of the threshing unit and record the
readings of the energy meter. Calculate power consumption at
no-load for one hour.
• Record the data according to item
2 Visual Observations - During and after completing power
consumption test, the observations shall be made visually and
recorded.

11. TEST AT LOAD
1 Short-Run Tests
• Install the thresher on level preferably on a hard surface and set the clearances, screen
slope, etc, as per manufacturer's recommendations. As far as possible. the test should
be conducted under close to still air condition
• Take sufficient quantity of the crop of the same variety The moisture content of the
grain shall be between 6 and 14 percent.
Attachment of Prime Mover and Thresher - Attach the thresher with a suitable prime
mover, preferably an electric motor. An energy meter or some form of transmission
dynamometer shall be fitted.
• The power delivered to the thresher may be supplied in the following ways: a) Direct
coupling of the prime mover with the main axle of the thresher. and b) Connecting the
prime mover with the help of flat or V-belt and pulleys with the main axle of the
threshers.
• In case of (a) the power delivered to the thresher would be the power output of the
prime mover; whereas in case of (b) the allowances for flat belt and V-belt drive
losses may be taken as 6 and 3 percent respectively

12. Analysis of the Samples - Analyse the samples obtained at different outlets
for different feed rates for the following:
a) Main grain outlet(s) - To be analysed for unthreshed grain, broken grain
and foreign material.
b) Straw outlet -- To be analysed for clean grain and untbreshed grain.
c) Sieve overflow - To be analysed for unthreshed grain and clean grain. The
average of analysis for three sets obtained at different feed rates shall be
reported.
d) Sieve underflow --- Take 16th or 1 kg of the quantity of the material
dropped through the sieves and analyse for clean grain and unthreshed
grain
Calculation
A =B + C + D
where A = total grain input per unit time;
B = quantity of ( threshed, clean) grain collected from an grain outlets) per unit
time;
C=quantity of broken grain from all outlets per unit time; and
D == quantity of unthreshed grain from all outlets per unit time

14. Threshing capacity or output capacity
The output capacity was estimated by weighing the total grain (whole and damaged)
received per hour at the main grain outlet of the thresher (IS: 6284-1985, 1986).
Threshing efficiency
Threshing efficiency is the threshed grain received from all outlets with respect to total
grain input expressed as percentage by mass the threshing efficiency was calculated by using
the formula and expressed in percentage (IS: 6284-1985, 1986).
Threshing efficiency (%) = 100 − percentage of un-threshed grain
Cleaning efficiency
Cleaning efficiency is clean grain received at main grain outlet(s) with respect to the
total grain mixture received at main grain outlet(s) expressed as percentage by mass. The
cleaning efficiency was calculated by using the formula (IS: 6284-1985, 1986)
Where,
CE= Cleaning efficiency, %
QCG = Quantity of clean grain obtained from the sample taken at main grain outlets; and
QT = Total quantity of the sample taken at main grain outlets.

15. LONG RUN TEST
Operate the thresher for at least 20 hours at load, which should be
covered by continuous run of at least 5 hours.
If facilities are available it may be run for 50 hours.
Record the major breakdowns, defects developed and repairs made .
Determination of Power Consumption
• In case of energy meter fitted prime mover, the difference between two
consecutive readings shall give power consumption for 60 minutes,
interval.
• In case of dynamometer fitted prime mover, the average reading taken
shall give the average torque required. Calculate the power
requirement by the following formula:

17. Factors affecting performance of thresher
1. Crop Factor:
• Crop Variety
• Moisture content of crop (grains and straw)
• Straw: Grain ratio
2. Machine Factor:
• Type of cylinder
• Diameter of cylinder
• Spike shape, size, number , arrangement
• Concave size, shape and clearance
• Feeding chute angle
3. Operational Factors:
• Cylinder speed
• Feeding rate
• Method of feeding(manual/ automatic)

18. Thank you