Testing and Evaluation of Mini Rice Combine Harvester
The combine harvester cuts the standing grain, threshes, and cleans it as it moves over the field. It takes the place of a rice reaper and a stationary thresher. It eliminates the tiresome piling of rice stalks prior to threshing. With the combine harvester, post-harvest losses are minimized.
The combine is adopted for harvesting small grains such as soybeans, sorghum, rice and other crops.
Principles of Operation
Harvesting refers to all operations performed in the field, which includes cutting of the rice stalks (reaping), laying out the paddy on the stubble to dry, stocking and threshing.
The basic operations performed by a combine are cutting the standing grain, feeding the cut grain into the cylinder, threshing the grain from the stalk or stem, separating the grain from the straws, cleaning the grain by removing the chaff and other foreign matters and bagging the threshed grains.
Outstanding Features
The Phil Rice B&S Mini Combine Harvester is used for reaping, threshing, cleaning, and bagging of grains in just one operation. It is suitable to small paddy field for dry and wet season harvesting with minimum grain losses of 1-2%. It allows harvesting even at night, lightweight, allow use of reliable 16-hp B&S cast iron engine locally designed and manufactured. Only two persons are needed to operate the machine.
Instrumentation
During the conduct of performance evaluation of the combine harvester, the following were used:
Digital Weighing Scale
Field Markers
Stop Watch
Steel Meter
Tachometer
Methodology
The combine harvester was operated to a 4-plot ready to harvest rice field. The field dimensions were measured using the push rule meter to get the area. Before the combine started the reaping, the crop standing condition and height were determined. RPM of the engine was also recorded using tachometer.
At the start of operation, downtime was recorded. To determine the speed of the combine, a 10-meter distance was measured. Reference points or field markers were set-up to guide where to start and stop the time recordings.
Four (4) different rice hills on the field were identified to determine the cutting height of the combine. It was measured from the ground surface to the tip of the cut rice tiller. Also, four (4) 1-m2 representative areas were measured. Fallen filled grains during harvesting were counted on these areas prior to grain loss computation.
At the end of the operation, four (4) 100-gram paddy samples were taken. These were used to determine the percent purity.
Data Gathering
In order to evaluate the performance of the Mini Rice Combine Harvester, several parameters were used.
Efficient Working Time, min
T_E = To - T_L
Where T_E=efficient working time ,min
To= total operating time,min
T_L=time loss,min
Forward Speed, km/h
s=d/t
Where s= forward speed, km/h
d=distance, 10-m
t=time, sec
Fuel Consumption1, L/hr
F_c1= V/T_o
Where F_c1= fuel consumption, L/ha
V= volume of gasoline used, L
T_o= total operating time,min
Fuel Consumption2, L/ha
F_c2= V/A
Where F_c2= fuel consumption, L/ha
V= volume of gasoline used, L
A= area, m2
Theoretical Field Capacity, ha/day
C_T=(s)(w)
Where C_T= theoretical field capacity, ha/day
s = forward speed, m/s
w = width of cut, 1.21-m
Actual Field Capacity, ha/day
C_A= A/T_o
Where C_A= actual field capacity, ha/day
A= area, m2
T_o=total operating time
Field Efficiency, %
E_f= C_T/C_A
Where E_f= field efficiency
C_T= Theoretical field capacity, ha/day
C_A= Actual field capacity, ha/day
% Grain Loss
% G.L.= (W/A_c)/(Y/A_T ) X 100
Where G.L= Grain Loss, %
W= weight of the grains expressed in a 1000 grain weight
A_c= area ofcollection
Y= net yield
A_T= total area
Grain Purity, %
P=(1- (W_u- W_c)/W_c ) x 100
Where P= grain purity, %
W_u=weight of uncleaned grain,g
W_c =weight of cleaned grain,g
Results and Discussion
Four rice field plots were selected for the performance evaluation of the Mini Rice Combine Harvester. Based from the results, the average cutting height of the machine was 44.69cm. It is 13.63 cm lower compared to the AMTEC’s result. However, it is recommended that reaping should be done below the panicle level.
Based from the tests done, it was observed that the machine was difficult to shift its speed from first (1st) gear to second (2nd) gear to reverse and vice versa. The brake did not function. Only the clutch was used to stop the machine from running. The speed recorded had an average of 1.84kph. It is slower compared to the 2.05 kph speed result of AMTEC.
During the testing, the average fuel consumed by the machine was 19.98 L/ha, which is nearer to the 19.62 L/ha of AMTEC.
On the four tests conducted, actual field capacity did not vary much. Likewise, the average actual field capacity result showed a little difference of 0.18 ha/day from the AMTEC’s result.
The average field efficiency of the combine was 64.44% which is less than the 86.6% result of AMTEC. The efficiency was affected by the total operating time and forward speed of the combine. The faster the machine and the shorter the operating time to finish the harvesting, the higher is the efficiency.
The average grain loss percentage was 2.02%. It is higher by 0.34% as compared to the AMTEC’s findings. However, the result is still outstanding. In most cases, harvesting incurs 1-3% loss while threshing adds 2-6% grain loss. These losses range from 3-6%. With the use of the machine, a 4% grain recovery is manifested.
Test resul t for average percent purity was 90.67% from the student’s evaluation while 90.3% from AMTEC. The high percentage of purity means that the blower worked efficiently in separating the unfilled grains, straws and other foreign matters.
Computations:
Forward Speed
To get the speed, make an average of the time recorded traveled at a distance of 20 m
Time Average
Plot 1
Time Average = (70+49+60)/3=56.67 sec
Plot 2
Time Average = (30+25.6+44.6)/3=33.4 sec
Plot 3
Time Average = (28+29+32.53)/3=29.84sec
Plot 4
Time Average = (38.48 +41.66+30.69)/3=36.94 sec
Forward Speed
Plot 1
s =((20 m)/(59.67 sec))( (3 600 sec)/(1 hr)) ( 1km/(1000 m)) = 1.21 km/hr
Plot 2
s= 2.16 km/hr
Plot 3
s=((20 m)/(29.84 sec))( (3 600 sec)/(1 hr)) ( 1km/(1000 m)) = 2.41 km/hr
Plot 4
s=((20 m)/(36.94 sec))( (3 600 sec)/(1 hr)) ( 1km/(1000 m)) = 1.95 km/hr
Average
s= (1.21+2.16+2.41+1.95)/4= 1.93 km/hr
Fuel Consumption
Plot 1
F_c1= V/T_o
= (0.75 L)/(0.30 hr)=2.5L/hr
Plot 2
F_c1= V/T_o
= (0.75 L)/(0.22 hr)=3.41L/hr
Plot 3
F_c1= V/T_o
= (0.75 L)/(0.26 hr)=2.88L/hr
Plot 4
F_c1= V/T_o
= (0.75 L)/(0.24 hr)=3 L/hr
Average
F_c1= V/T_o
= (2.5+3.41+2.88+3)/4=2.95 L/hr
Actual Field Capacity
Plot 1
C_A= ((360 m^2)/0.3hr)((1 ha)/(10000 m^2 ))((8 hr )/(1 day))= 0.96 ha/day
Plot 2
C_A= ((392 m^2)/0.22hr)((1 ha)/(10000 m^2 ))((8 hr )/(1 day))=1.43 ha/day
Plot 3
C_A= ((360 m^2)/0.26hr)((1 ha)/(10000 m^2 ))((8 hr )/(1 day))=1.11 ha/day
Plot 4
C_A= ((392 m^2)/0.24hr)((1 ha)/(10000 m^2 ))((8 hr )/(1 day))=1.31 ha/day
Average
C_A= (0.96+1.43+1.11+1.31)/4=1.31 ha/day
Theoretical Field Capacity
Plot 1
C_T = (1.21 km/hr) (1.21 m) ((1 ha)/(10 000 m^2 )) ((1 000 m)/(1 km))((8 hr)/day)= 1.17 ha/day
Plot 2
C_T= (2.16 km/hr) (1.21 m) ((1 ha)/(10 000 m^2 )) ((1 000 m)/(1 km))((8 hr)/day)= 2.09 ha/day
Plot 3
C_T= (2.3 km/hr) (1.21 m) ((1 ha)/(10 000 m^2 )) ((1 000 m)/(1 km))((8 hr)/day)= 2.23ha/day
Plot 4
C_T= (1.98 km/hr) (1.21 m) ((1 ha)/(10 000 m^2 )) ((1 000 m)/(1 km))((8 hr)/day)= 1.92 ha/day
Average
C_T=(.1.17+2.09+2.23+1.92)/4=1.85 ha/day
Field Efficiency
Plot 1
E_f = 0.96/(1.17 ) x 100=82.05%
Plot 2
E_f= 1.43/(2.09 ) x 100=68.02%
Plot 3
E_f= 1.11/(2.23 ) x 100=49.78%
Plot 4
E_f= 1.18/1.92 x 100=61.46%
Average
E_f= (82.05%+ 68.02%+49.78%+ 61.46% )/4=65.44%
Grain Purity
Plot 1
P=(1- (100- 91)/91) x 100 = 90.11%
Plot 2
P=(1- (100- 94)/94) x 100 = 93.62 %
Plot 3
P=(1- (100- 89)/89) x 100 = 87.64%
Plot 4
P=(1- (100- 92)/92) x 100 = 91.30%
Average
P = ( 90.11+ 93.62+ 87.64+91.30 )/4 = 90.66%
% Grain Loss
Plot 1
% G.L. = ((734 grains)(26grams/1000grams)(1kg/1000grams))/((4.75 bags )(50)/360m^2 ) x 100=2.89%
Plot 2
% G.L.= ((535 grains)(26grams/1000grams)(1kg/1000grams))/((4 bags )(50)/392m^2 ) x 100= 2.73%
Plot 3
% G.L.= ((350 grains)(26grams/1000grams)(1kg/1000grams))/((4.5 bags )(50)/360m^2 ) x 100= 1.46%
Plot 4
% G.L.= ((257 grains)(26grams/1000grams)(1kg/1000grams))/((4.75 bags )(50)/392m^2 ) x 100= 1.01%
Average
% G.L.= (2.89%+ 2.73%+ 1.46%+ 1.01% )/4=2.02 %
Table 1.0 Testing and Evaluation for Mini Rice Combine Harvester
Parameters Plot 1 Plot 2 Plot 3 Plot 4 Average AMTEC Evaluation
April 22, 2010 April 22, 2010 April 22, 2010 April 22,2010
Phil Rice Field Area Phil Rice Field Area Phil Rice Field Area Phil Rice Field Area
Crop Stand Nearly lodged Nearly lodged Nearly lodged Nearly lodged
Variety NSIC RC 160 NSIC RC 160 PSB RC 82 PSB RC 82
Height, cm. 79. 27 82. 3 78.03 80.0 78.4
Field Condition Area, m2 360 392 360 392 376
Soil condition Dry Dry Dry Dry
Cutting Height, cm. 53. 17 44.9 39.83 40.3 44.69 54.3
Total Operating Time, hr. 0.3 0.22 0.26 0.24 0.26
Total Operating Time, min 18 13.2 15.6 14.4 15.3
Down Time, sec 47 34
Eff. Working time, min 11.33 10 12 10.2 10.88
Actual Field capacity, ha./day 0.96 1.43 1.02 1.31 1.18 1.0
Theoretical Field capacity, ha./day 1.17 2.09 2.23 1.92 1.85
Field efficiency, % 82.05 68.42 49.78 61.46 65.44 86.6
Forward Speed, kph 1.21 2.16 2.41 1.95 1.93 2.05
Engine RPM 800-900 800-900 800-900 800-900 800-900
Fuel consumption Liters 0.75 0.75 0.75 0.75 0.75
Hours used 0.56 0.39 0.39 0.41 0.44
li./hr. 2.5 3.41 2.88 3 2.95
li./ha 20.83 19.13 20.83 19.13 19.98 19.62
Yield in bags @ 45kg/bag 4.75 4 4.5 4.75 4.5
Grain losses
(average) # of grains/m2 734 535 350 257
469
% 2.89 2.73 1.46 1.01 2.02 1.68%
Purity, % 90.11 93.62 87.64 91.30 90.66 90.3