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Threshing Machines(TM)
Prepared by
Er.Uttam Raj Timilsina(MSc.Engineering,IIT
Roorkee)
Professor of Agricultural Engineeri...
Threshing Machines(TM)
• Threshing methods and their mechanization
• Types of threshers,their working principle and
constr...
TM
• Threshing :- It is the seperation/removal of grains from
harvested crop by striking action, beating
action,treading o...
Hand beating
Hand beating
Animal hoobing
TM
• Mechanization of threshing methods:-The threshing
operation of cereals crops has been mechanized in
developed countri...
TM
• The combine harvester is a latest development in mechanization or
modernization of harvesting, threshing and cleaning...
TM
• Threshers:-Threshers are the machine to perform the works
required for threshing mechanism or threshing process which...
Pig or spike tooth cylinder
Rasp bar threshing cylinder/drum
Wire loop
Rasp bar type
Spike tooth type
TM
 Types of thresher based on source of power available
-Manually operated like pedal thresher
-Engine operated thresher...
Hold on type thresher
TM
Parts of thresher
TM
Threshing process/mechanism-A feeder schute is
located in front of threshing drum.Most thresher
consists of rasp-bar t...
Threshing drum
Threshing process
Separating process/ Mechanism:-The main
separation of the grain from the straw is
through the concaves.The loose grains m...
Cleaning process/mechanism:-The function of
cleaning unit is to remove chaff or other foreign
matters from the grain.This...
Cleaning process
TM
• Parts of multi crop thresher and their function:-
 Feeding schute-it perform the feeding action of crop
materials ca...
Thresher
Perforated concave
TM
Top sieve- it perform the action of sieving
Oscillating sieves –It perform the action of
sieving as well as separatin...
Rice thresher
Pedal thresher
Working condition
Non safety operation
Threshing yard
Rice thresher
thresher
Multi crop thresher
• Maize sheller- it is a machine which separate
the grain(kernels) from maize cobs. It consist
of peg-studded cylinder of ...
TM
• Types of corn sheller
• Spring sheller-It has a plate under spring pressure
to hold the ears against a rotating disc ...
Multi crop thresher
• Factor affecting thresher performance-
Plant or crop factor-types of crops,moisture
content of grains,variety of crops ...
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
Threshing machines
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Threshing machines

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Er. Uttam Raj Timilsina(MSc.Engineering,IIT Roorkee)
Professor of Agricultural Engineering,Agriculture and Forestry University (AFU), Rampur, Chitwan, Nepal
uttamrajtimilsina@gmail.com
*All Right Reserved**
Uploaded and Shared by AgriYouthNepal

Published in: Engineering
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Threshing machines

  1. 1. Threshing Machines(TM) 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. 2. Threshing Machines(TM) • Threshing methods and their mechanization • Types of threshers,their working principle and constructional details • Factors affecting thresher performance • Maize sheller and its construction details
  3. 3. TM • Threshing :- It is the seperation/removal of grains from harvested crop by striking action, beating action,treading or rubbing action.It is accomplished either by treading the grain under the feet of man or hooves of animals,on striking the grains with stick or beating or impacting it on hard and rough surface. • Method of threshing:-  Hand beating with capacity of 17-20 kg/hour  Treading or rubbing with bullock with the capacity of 140 kg/hour  Pedal Thresher with the capacity of 40- 45kg/hr  Multicrop thresher with the threshing capacity of 300- 500 kg/hr
  4. 4. Hand beating
  5. 5. Hand beating
  6. 6. Animal hoobing
  7. 7. TM • Mechanization of threshing methods:-The threshing operation of cereals crops has been mechanized in developed countries in comparison to threshing operation of pulse crops.oilseed crops.Threshing of wheat crop has been totally mechanized in comparison to other cereal crops like rice.Threshing of rice/paddy crop is still carried out manually and to a small extent by treading the crops under tractor tyres in under developing countries.Now a days mechanization or modernization of threshing operation is carried out in combine harvester where harvesting, threshing ,winnowing,cleaning the threshed crops is done in a single operation by a single unit of machine called combine harvester.
  8. 8. TM • The combine harvester is a latest development in mechanization or modernization of harvesting, threshing and cleaning operation of grain crops.Various action research /experimental research or doable research were done to develop thresher machines for threshing operation of cereals crops in different regions of the world and with the successful result of those research now we got the present thresher.The research which is a never ending process is continue in different parts of world to modernize the present threshers to fulfill the demand and requirement of future days .Even these days not only for thresher but for the modernization of present combine harvester, research and development is continue for future ,specially to minimize in size and shape as well as to maximize working capacity,efficiency and better performance of machines depending upon the source of power available ,use of electronic and computer devices to fulfill the demand of modernized working performance .
  9. 9. TM • Threshers:-Threshers are the machine to perform the works required for threshing mechanism or threshing process which separates the grains from the stalks. A general purpose thresher capable of threshing a variety of crops is operated by 5 hp -8 hp electric motor or engine with the threshing capacity of about 200 kg/hr or 1600 kg /day of 8 working hours at a rotary speed of 550- 850 rpm.Thresher mostly consists of different units to perform different actions/ mechanisms like threshing, seperating and,cleaning  Types of thresher based on threshing unit:- - Spike tooth or pigs type thresher -Rasp bar types type thresher, -Angle bar types, -wire loop types .
  10. 10. Pig or spike tooth cylinder
  11. 11. Rasp bar threshing cylinder/drum
  12. 12. Wire loop
  13. 13. Rasp bar type
  14. 14. Spike tooth type
  15. 15. TM  Types of thresher based on source of power available -Manually operated like pedal thresher -Engine operated thresher or tractor operated thresher with power range of 5-40 hp and capacity range of 200-500 kg/hr -Self propelled engine type as combines harvester  Types of thresher based on crop -Wheat thresher -Rice thresher- straw hold on type or throw in type -Corn sheller -Multi crop thresher -Other crops or special crops thresher
  16. 16. Hold on type thresher
  17. 17. TM
  18. 18. Parts of thresher
  19. 19. TM Threshing process/mechanism-A feeder schute is located in front of threshing drum.Most thresher consists of rasp-bar type cylinder with rasp bar of 6-8 in number,half of these have right hand ribbing and half left hand ribbing and are fixed alternatively. It also consists of angle bar type cylinder as well as spike tooth-type cylinder and concaves. The grain is rubbed or beated to seperate from the stalk without cutting the stalks and damaging the grains between spike tooth or rasp bar or angle bar type cylinder and perforated concave type basket
  20. 20. Threshing drum
  21. 21. Threshing process
  22. 22. Separating process/ Mechanism:-The main separation of the grain from the straw is through the concaves.The loose grains mixed with straw as it leaves the cylinder are separated by oscillating straw rack.These racks may consist either of one piece or of several sections which alternately move with a slight elliptical action to pitch the straw rewarded with each movement
  23. 23. Cleaning process/mechanism:-The function of cleaning unit is to remove chaff or other foreign matters from the grain.This is done by passing uncleaned grains over a series of oscillating sieves and screens through which a current of air is forced/blowed by a fan/blower.Different types of sieves and screens are available for different kinds of crops.Partially unthreshed heads of grain termed tailings drops into thr auger which deliver the tailings to an elevator which in turn conveys the materials upward to the threshing drum for re-threshing action.
  24. 24. Cleaning process
  25. 25. TM • Parts of multi crop thresher and their function:-  Feeding schute-it perform the feeding action of crop materials called feeder  Threshing cylinder/drum –it is generally 1.4-1.5 m long and 55-65 cm in diameter and perform the threshing action ,fitted with cylinder pegs,beaters of rasp bar type or angle bar type or spike tooth type or wire loop type threshing devices  Concave type perforated bucket- It seperate the grain and straw,bhusa/chaff  Blower -It blow or supply air for cleaning as well as forcing chaff/straw out of the machine
  26. 26. Thresher
  27. 27. Perforated concave
  28. 28. TM Top sieve- it perform the action of sieving Oscillating sieves –It perform the action of sieving as well as separating straw and grain Straw/chaff discharge outlet- It discharge chaff out of machine Grain hopper-It allow the cleaned and collected grains to collect in bags/containers Transport wheel-It support and allow the whole machine to move forward and backward
  29. 29. Rice thresher
  30. 30. Pedal thresher
  31. 31. Working condition
  32. 32. Non safety operation
  33. 33. Threshing yard
  34. 34. Rice thresher
  35. 35. thresher
  36. 36. Multi crop thresher
  37. 37. • Maize sheller- it is a machine which separate the grain(kernels) from maize cobs. It consist of peg-studded cylinder of diameter 20 cm rotating in side a cylindrical screen.The shelled corn drops through the holes in the screen for cleaning process.Simple type and small handy corn sheller is also available with rotating type tooth disc.
  38. 38. TM • Types of corn sheller • Spring sheller-It has a plate under spring pressure to hold the ears against a rotating disc which loosens and separate the kernels(grains) from the cobs.The grain pass downwards through the cleaning unit and the cobs are rejected by conveyer • Cylinder type-These are the bigger and larger in capacity engine or tractor operated as 10-35 hp with the cylinder speed of 600-1000 rpm
  39. 39. Multi crop thresher
  40. 40. • Factor affecting thresher performance- Plant or crop factor-types of crops,moisture content of grains,variety of crops ,drying of crops etc. Machine or mechanical factor-types or models of machines,manufacturing quality,operating quality of machine ,care and maintenance of macnines, handelling of crops,threshers etc. Miscellaneous factors-Safety factors for grains injury etc

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