COMBINE HARVESTER

Combine harvestingFeaturescombines cutting, threshing, cleaning and haulingtracks for mobility in wet fieldsAdvantageshigh capacitylow total harvest lossesDisadvantagesRequires relatively large field sizesProblem in terraced fields

PARTS OF COMBINE HARVESTER

Combine harvester

CROP TIGER COMBINE

COMBINE HARVESTER

PARTS OF A COMBINEHEADER UNITFEEDING UNITTHRESHING & SEPERATION UNITCLEANING UNIT

HEADER UNIT REELCUTTERBARCROSS AUGURHEADER PLATFORM

REELPrevents shattering of crop Moves the crop uniformly towards the cutterbarHolds the crop until it is cut by the cutterbarReel must be square, level, at proper height and run at right speedTypes of reelBat type4-6 wooden slatsNot suitable for lodged cropSlapping action causes more shattering if the crop is over ripeTyne typeSpring tyne fittedAngle can be changedEffective for both standing and lodged crop

CUTTERBARCutterbarTop serrated knifesSpeed: 500 1600 rpm of the crankSpeed: 1.2 to 1.5 m/sHeight of cut: 5 100 mm (28mm -69mm for crop tiger)

Fixed finger on the cutterbar, through which the knives runKnife blades riveted on a knife stripDriveBell crank leverWobble mechanismStroke: 76.2 mm

Drive to different parts of the combine

AUGERMade of steel metalSmooth in the centreScrew threadOne thread left handed , other right handedAt the centre retraceable fingers (pongs) are providedFingers come out of the housing and moves the crop towards the conveyor Height of the fingers can be adjusted Wheat: 15 -20 mmPaddy: 15 20 mm

FEEDING UNITTakes the crop from cutterbarTension of the conveyor chain importantLower conveyor shaft floats to move the crop smoothlyInsufficient tension may cause jumping of the chain and fast wear of the conveyorBest setting is when one of the serrated bottom touches the bedSerrated Feeder channel providedSpeed: 2.5 -3 m/s

THRESHING & SEPERATING UNITStone trapCylinderConcaveRear beater

Types of threshing cylindersSpike toothRasp barAngle bar typeWire loop type

Principles and types of threshing mechanismForces : Impact Impact and friction Type of threshing elementsCross flow rasp bar cylinder (48-60cm dia) with open gratesAxial flow rap bar cylinderSimilar to cross flow raspbar but number: 2pair 180 0 apartMaterial moves several times across the helical pathEasy to adjust and maintainMost crop (wheat, maize, rice also)CorrugatedDirection of corrugation of one bar is opposite to the otherThreshing is done by the front edge of the rasp barThe serrated face aids in separationSpike tooth cylinderIf concave has teeth, more combing actionNo of teeth: 2,4,6 in each slatMore positive feedingRequires less power

CONCAVEConcaveImpact force importantRubbing force contribute to threshingBut holds the crop for impactOpening on the concave allows seed separationA combination of threshing cylinder speed and concave clearance is importantConcave clearance importantHigh cylinder speed, less concave clearance &vice versaMore moisture content, high cylinder speed and low c.cMore concave length more grain separation at a diminishing rateGrain separation can be as high as 90%Large cylinder dia more concave lengthCentrifugal force required to separate grain decreases

Additional cylinder and concave

Types of threshing methodsTangential threshingUsed in conventional combinesFor high capacity, additional cylinders useRotary threshingSuitable for corn, rice, soybeanMore sensitive to crop moisture content

Performance characteristics of rotary and tangential threshing devices Axial threshing unit has higher power requirement, , higher MOG separation, low grain damage, high throughput

Threshing cylinder speed

Effect of peripheral speed on losses and damageLow speed, more cylinder loss (unthreshed)More speed more grain damage

Effect of certain factors on cylinder performance

Grain separation

Combine harvestingCutting, hauling, threshing, cleaning in one combined operationCapacity: > 0.5 ha/hLabor requirement: 1 OperatorCapital cost: > $ 250,000

Jhon Deeree

John Deere

Self propelled combine harvesterCapacity:0.75 acre/h, Cost: Rs 15,00,000/-

Self propelled combine harvesterCapacity:1.0 acre/h, Cost: Rs 12,00,000/-

Tractor mounted combine harvesterCapacity:1.0 acre/h, Cost: Rs 12,00,000/-

Operational partsCutting & pickingThreshingSeparation of seeds & chaff from strawCleaning the chaff & debris from grainsCollection of grains

PARTS OF COMBINE HARVESTER

Cutting and picking unitCrop dividerReel Bat type (4 to 6 wood or metal bats) Less expensive tyne type (pick up type)Reel index: 1.25 1.5Lodged crop: reel axis ahead of cutterbar (23 to 30 cm)AugurCutterbarSpeed: 400 550 rpm of the crankHeight of cut: 5 100 mmHeader platformconveyor

Principles and types of threshing mechanismForces : Impact Impact and friction Type of threshing materialCross flow rasp bar cylinder (48-60cm dia) with open garatesAxial flow rap bar cylinderSimilar to cross flow raspbar but number: 2pair 180 0 apartMaterial moves several times across the helical pathEasy to adjust and maintain Spike tooth cylinderIf concave has teeth, more combing actionNo of teeth: 2,4,6More positive feedingRequires less power ConcaveImpact force importantRubbing force contribute to threshingBut holds the crop for impact

Performance of threshing cylinderSeed detachmentSeed separation

Self propelled fodder harvesterPower: 3.75 kW engine

HARVESTING: It is the operation of cutting, picking, plucking, digging or a combination of these operations for removing the crop from under the ground or above the ground and removing the useful part of fruits from plants. Crop harvesting action can be done by four ways as given below: Slicing action with a sharp tool. Tearing action with a rough serrated edge. High velocity single element impact with sharp or dull edge. Two elements scissors type action.