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Abstract—
A simple mobile engine-driven pneumatic paddy
collector made of locally available materials using local
manufacturing technology was designed, fabricated, and tested for
collecting and bagging of paddy dried on concrete pavement. The
pneumatic paddy collector had the following major components:
radial flat bladed type centrifugal fan, power transmission system,
bagging area, frame and the conveyance system. Results showed
significant differences on the collecting capacity, noise level, and fuel
consumption when rotational speed of the air mover shaft was varied.
Other parameters such as collecting efficiency, air velocity,
augmented cracked grain percentage, and germination rate were not
significantly affected by varying rotational speed of the air mover
shaft. The pneumatic paddy collector had a collecting efficiency of
99.33% with a collecting capacity of 2685.00kg/h at maximum
rotational speed of centrifugal fan shaft of about 4200rpm. The
machine entailed an investment cost of P 62,829.25. The break-even
weight of paddy was 510,606.75kg/yr at a collecting cost of 0.11
P/kg of paddy. Utilizing the machine for 400 hours per year
generated an income of P 23,887.73. The projected time needed to
recover cost of the machine based on 2685kg/h collecting capacity
was 2.63 year.
Keywords—
Mobile engine-driven pneumatic paddy collector,
collecting capacity and efficiency, simple cost analysis
.
I. I
NTRODUCTION
ICE farming in the Philippines took a complete turn when
modern technologies were introduced which include the
adoption of high yielding varieties, application of inorganic
fertilizer, better crop pest control, water management, and
other improved farming practices. The immediate adoption of
these new technologies was the result of a greater demand to
increase production to cope with the fast growing population
of Filipinos which was estimated to grow to 103 million by the
year 2015 AD[7].
The adoption of improved production technology increases
yield and likewise gives birth for new challenges on how to
deal or handle tons of wet paddy that need to be dried to
maintain good rice quality, storability and high commercial
value [5].
Drying is the process that reduces grain moisture content to
a level where it is safe for storage. Drying is the most critical
operation after harvesting a rice crop. Delays in drying,
incomplete drying or ineffective drying reduce grain quality
Sony P. Aquino, is with the Department of Agricultural Engineering,
College of Engineering, Nueva Vizcaya State University, Bayombong, Nueva
Vizcaya.
Helen F. Gavino, Victorino T. Taylan, and Teresito G. Aguinaldo are with
the Department of Agricultural Engineering, Institute of Graduate Studies,
Central Luzon State University, Science City of Muñ0z, Nueva Ecija.
and result in losses. Drying and storage are related processes
and can sometimes be combined in a piece of equipment (in-
store drying). Storage of incompletely dried grain with
moisture content higher than the acceptable level leads to
grain deterioration regardless of storage facility used. In
addition, the longer the desired grain storage period, the lower
the required grain moisture content must be [9].
Confronted by problems on drying, the government
activated various agencies like the Department of Agriculture
(DA), National Food Authority (NFA), Philippine Rice
Research Institute (PHILRICE), Philippine Center for
Postharvest Development and Mechanization (PHILMECH),
and other institutions to take steps to ease the problems.
To date with all the postharvest technologies being
developed and offered by the government, there are gray areas
in the postharvest aspect of drying paddy that should
harmonize with the practice of small farmers as well as big
rice millers and traders.
Several drying technologies were introduced to farmers, big
rice millers and traders. The rate of return from sun drying
operation is high while the rate of return from the best
mechanical dryers available in the country is low. Farmers
unanimously use sun drying and none adopts mechanical
dryers [12]. In the light of this development and present
practices, it is obvious that sun drying will stay as one of the
post harvest technologies in the Philippines.
Angeles cited the inappropriateness of imported
technologies over the country’s socio-economic conditions
had created awareness of developing our own equipment and
machine out of local materials using locally manufacturing
technologies and manpower [2]. Owing to significant
development of sun drying as a socially accepted technology
and its possibility of development through mechanization, he
also added that continuous efforts have to be undertaken to
conduct development studies of local machinery based on the
appropriate features of existing commercial machinery from
developed countries and emerging economies.
It is for this reason that this research was undertaken to
design, fabricate a pneumatic paddy collector out of local
material using locally manufacturing technology and man
power that would help farmers, rice traders and millers to
contribute to the reduction of losses, save time, labor, and cost
of collecting and bagging.
Design, Fabrication and Performance Evaluation of
Mobile Engine-Driven Pneumatic Paddy Collector
Sony P. Aquino
, Helen F. Gavino, Victorino T. Taylan, and Teresito G. Aguinaldo
R
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
783International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
II. M
ATERIALS AND
M
ETHODS
A. Conceptual Framework
The traditional sundrying method of a paddy is still widely
practiced by most farmers. The practice includes hauling of a
paddy in bags to the drying area, spreading out the paddy in
the drying floor using wide board, then evened and slightly
furrowed with wooden rakes. Mixing and turning the paddy
are done regularly to ensure that the paddy is dried evenly.
After drying, the paddy is piled using a wooden board. After
wards, the paddy is placed into a bag using a metal scoop
(Panake). All of the above operations are done manually
consuming too much time and effort [5]. Collecting and
bagging operation is considered one of the difficult tasks in
sundrying.
This study was then conceptualized by looking into existing
designs of pneumatic conveyor from developed, emerging and
developing countries that could replace manual bagging and
collecting of paddy on concrete pavement during sundrying.
Based on the results, good features of the existing design were
considered for adoption, adaptation, and simplification to
come up with the prototype machine. Design requirements
satisfying local condition were identified. Design data then
were based on market information of available parts and
components of machine. Based on design requirements and
design data, a design drawing was prepared. Fabricated
prototype was subjected to evaluation to determine its
operating characteristics. Fig. 1 shows the conceptual
framework of the study.
INPUT
• Relevant information gathered on existing design of
pneumatic paddy conveyor, paddy characteristics,
and availability of machine parts and components
PROCESS
•
Design conceptualization, calculations and design
plan of the machine
• Fabrication of machine components
• Performance evaluation of the machine
OUTPUT
•
Mobile engine-driven pneumatic paddy collector
• Operating characteristics of the machine
Fig. 1 Conceptual framework of the study
B. Design of Major Components
Design requirements were synthesized based on the analysis
of findings in the various literatures reviewed and from
patented and commercial pneumatic paddy collectors. Some of
the identified design requirements were the following: 1) the
machine should collect paddy at varying thickness under sun
drying condition and bag the same; 2) the machine should help
reduce drudgery and quicken collecting and bagging of paddy
during sun drying; and 3) the machine should be of
intermediate technology, made from local materials using
local manufacturing technology, simple and safe to operate
and maintain, functionally and structurally sound, and with
minimum tooling [2]
1. Power Transmission System
Design of power transmission system was based on
Philippine Agricultural Engineering Standards [13]. The
design data gathered from the literature reviews that were
considered in the design were the following:
a. Prime Mover
Power : 7.5kW[10]
High speed engine to match the required rpm of the air
mover
Engine shaft diameter: 25.4mm
Direction of drive shaft rotation: counterclockwise
b. Air mover
Service factor (Delivery): 1.3 [13]
Direction of driven shaft rotation: clockwise
2. Air Mover
The air mover used in the study was radial flat bladed
centrifugal fan. The blade 380 mm Ø is like a paddle wheel
with side rims. The blades were perpendicular to the direction
of the wheel's rotation and the fan runs at a relatively medium
speed to move a given amount of air. The radial blade type
was designed for material handling applications, features
rugged construction and simple field repair.
3. Suction Nozzle Assembly
Design of the suction nozzle assembly was based on
Walinga design. Design data needed in the design were the
following: 1) thickness of paddy when drying in concrete
pavement, 2-4cm [8]; 2) diameter of the suction pipe, 80mm;
and 3) anthropometric data such as knuckle-to-elbow length,
elbow height, and hand grip diameter. Overall length of the
suction nozzle assembly was determined using (1) [6].
ß
ſ
(1)
where: z = overall length
y = elbow height
x = knuckle-to-elbow length
ß = angle made by arm from the vertical, 110
o
ſ = angle made by the handle with the horizontal, 45
o
4. Air-paddy Separator
Cyclone separator was used as air paddy separator. Design
of the cyclone separator was based on the diameter (d) of the
suction pipe and the recommended typical proportion of
cyclone separator [15]. Dimension of the cyclone separator
was determined using (2)-(4).
(2)
(3)
(4)
where: D =diameter of the suction pipe, mm
L =height of the cylindrical portion, mm
Lc =height of the conical portion, mm
Db =bottom diameter of conical portion, mm
World Academy of Science, Engineering and Technology
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International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
Du =upper diameter of the conical portion,
C. Fabrication and Assembly of the Machine
1. Power Transmission System
A 14.20-hp air cooled, four stroke cycle, single cylinder,
direct injection, high speed diesel engine was used as prime
mover of the paddy collector. The prime mover was connected
to the frame using high strength 10 mm Ø x 75 mm bolt. The
power from the prime mover is transmitted to the shaft of
centrifugal fan using 200 mm Ø double groove driver pulley,
125 mm Ø triple groove driven pulley, and 2 pieces of V-belts
(B-81 section)
2. Air Mover
A radial flat bladed centrifugal fan was used as air mover of
the machine. The blade 380 mm Ø was like a paddle wheel
with side rims. The blades were perpendicular to the direction
of the wheel's rotation and the fan runs at a relatively medium
speed to move a given amount of air. Prior to the installation
of the centrifugal fan, a 10 mm Ø hole was made using power
drill. The centrifugal fan was connected to the frame using 10
mm Ø x 37.5 mm bolt with nut and washer.
3. Conveyance System
The conveyance system of the paddy collector included
suction nozzle assembly, suction hose, air- paddy separator,
check valve, and diverter valve assembly.
Suction Nozzle Assembly
The suction nozzle is an important device in vacuum
conveying system. The suction head was flat. A gauge 16
galvanized iron sheet was used in the fabrication of the
rectangular suction nozzle head. Downstream portion of the
suction nozzle assembly was made of 80 mm Ø PVC pipe. It
was provided with a G. I. pipe handle and two 37.5 mm Ø
plastic wheels to regulate the suction depth during operation.
Suction Hose
A 75 mm diameter, 3 m long vinyl wire reinforced flexible
hose was used as conveyance line from the suction nozzle
assembly to the air-paddy inlet of the cyclone separator. The
air outlet at the top of the cyclone separator was connected to
the air inlet of the centrifugal fan using 100 mm vinyl wire
reinforced flexible hose.
Air- Paddy Separator
A cyclone separator was used as air-paddy separator of the
machine. The cyclone separator included a 600 mm Ø x 300
mm high cylindrical and 600 x 150 x 900 mm (upper diameter
x lower diameter and height) conical truncated housing. The
cylindrical housing has a 100 mm Ø axial air outlet at the top,
and a 100 x 100 mm tangential air-paddy inlet at the upper
wall. The conical-shaped housing was provided with a paddy
outlet at the bottom in communication with the inlet of check
valve and swing diverter assembly. The cyclone was made of
gauge 16 galvanized iron sheets. The cyclone separator was
supported by angular bar welded to the main frame and it was
installed just above the bagging area of the machine.
Check Valve and Paddy Diverter Assembly
A swing diverter assembly was used to divert the flow of
paddy into two routes for continuous bagging during
operation. The assembly was made of 2.3 mm thick mild steel
plate, flange bearing attached to the side wall of the valve that
supports the 12 mm Ø swing gate shaft, and 15 mm Ø G. I.
pipe connected to the 25 x 6 mm flat bar arm of the swing gate
shaft to actuate the swing gate in diverting the flow of paddy
during bagging operation. The check valve was made of 2.3
mm thick mild steel plate; the gate was made of rubber and 2.3
mm thick MS plate welded to a 12 mm square bar; the square
bar was connected to a level arm made of 6 mm x 25 mm flat
bar, 10 mm Ø x 75 mm bolt with nut and 6 mm thick 75 mm
Ø circular plate; the lever arm was connected to the round bar
of the fabricated cylinder hinges made of G. I. pipe.
4. Bagging Section
The bagging section below the cyclone separator supports
two sacks to be filled with paddy alternately for continuous
bagging during operation. It was made of a 2.3 mm thick mild
steel plate welded from the top of a channel bar main frame. A
framed wire mesh was provided between the flat base part of
the bagging section and the prime mover to protect the sack
from the moving parts of the prime mover and the power
transmission system. A hook welded to the frame wire mesh
and the diverter valve was provided to hold the sack during
bagging operation.
5. Frame
The main frame was fabricated using 75 mm channel bar
and 6 x 40 mm angular bar cross members. Upper support
frame connected to main frame was made of 6 x 40 mm
angular bar. The main frame was provided with two swivel
caster rear wheels and two solid rubber front wheels and 32
mm Ø G. I. pipe push handles for mobility.
D. Principles of Operation
A 14.20-hp air cooled, four stroke cycle, single cylinder,
direct injection high speed diesel engine provides power
through the V-belt and pulley transmission system to drive the
radial flat bladed centrifugal fan. The centrifugal fan provides
suction to collect paddy without passing through the impeller
of the fan. Paddy is collected and conveyed by an intake air
stream through the suction nozzle and flexible hose where it is
drawn to the cyclone separator. When the air-paddy mixture
enters the cyclone separator, the paddy is separated from the
air; the air is drawn to the inlet of the centrifugal fan while the
paddy falls down because of its weight and centrifugal force
which cause it to move outward toward the wall during its
downward helical travel. As the paddy approaches the wall,
the velocity decreases because of wall friction and the paddy
settles into the bottom of the cyclone separator. The check
valve attached to the bottom of the cyclone separator prevents
the air being sucked into the cyclone other than the suction
hose during the start of the operation and unloads the grains
from the cyclone separator. The swing diverter assembly at the
bottom of the check valve diverts the flow of paddy into two
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
785International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
routes (2 sacks) alternately for continuous bagging of paddy
during operation. Two laborers are needed to operate the
machine: one is in-charge in bagging at the bagger, and
pushing the machine during operation; and the second is
responsible in moving the suction nozzle over the paddy
during collection operation.
E. Performance Evaluation
1. Preparation of Test Materials
Five cavan rice paddy per replication was used as test
material. A medium grain variety (C-18) having initial
moisture content of 14- 15 % was used in the study. The
paddy was spread manually on the 1.5 x 15 m concrete
pavement evenly at approximately 3 cm thick.
2. Measurement of Operating Characteristics of the
Machine
Collecting Capacity
This refers to the quantity of paddy collected per unit time.
Collecting capacity of the machine was determined using (5).
(5)
where: F
c
= Collecting capacity, kg/h
W
pc
= Weight of collected paddy, kg
T = Total time of collection, h
Collecting Efficiency
The collecting efficiency of the machine is the ratio of
paddy collected and the sum of paddy collected and suction
losses. A single pass over the 2-4 cm thick paddy using the
suction nozzle of the machine was done to collect the paddy
spread on a 1.5 x 15 m concrete pavement. The collecting
efficiency of the machine was determined using (6).
(6)
where: C
e
= collecting efficiency, %
W
pc
= weight of paddy collected, kg
S
l
=Suction loss, kg
Noise Level
The noise emitted by the machine, with or without load,
was measured using a noise level meter both at the location of
the operators and baggers. The noise, expressed in db (A), was
taken approximately 5cm away from the ear level of the
operators and baggers.
Air Velocity
The air velocity generated by the air mover at the inlet of
suction nozzle without load was measured using an air
velocity meter in m/s.
Fuel Consumption
The amount of fuel consumed per replication by the prime
mover in L/h. The fuel tank was filled to its capacity, after
each test trial the tank was refilled using graduated cylinder.
The amount of refueling is the fuel consumption for the test.
When filling up the tank, keep the tank horizontal so as not to
leave empty space in the tank.
3. Grain Quality Analysis
The grain samples taken before and after the test were
subjected to quality analysis. The following were determined.
Augmented cracked grains percentage
The percentage of augmented cracked grain after using the
machine was determined using (8).
(7)
where: C
gb
=Percent cracked grains of sample taken from the
grains collected by the machine
C
gc
=Percent cracked grains of sample taken from
control sample
(8)
Ncg =Number of cracked grains taken from selected
100-grain sample
Ng =Number of selected grains sample (100)
Germination Rate
This refers to the germination rate of grains and it was
computed using (9). To determine the germination rate, one
hundred grains were taken at random from each sample. For
each treatment two samples were taken, first sample was taken
from grain spread in the concrete pavement (Control sample)
and the second sample was taken from the grains collected by
the machine.
(9)
where: G
r
=Germination rate, %
N
gg
=Number of grains germinated
T
g
=Total number of grains
4. Simple Cost Analysis
Simple cost analysis was done to determine financial and
economic indicators of the mobile engine-driven pneumatic
paddy collector. The annual cost equation by Hunt [4] was
used in performing the simple cost analysis.
(10)
where: AC =Annual cost, P/yr
FC = Fixed cost, P/yr
W =Total weight of paddy, kg/yr
Vc =Variable cost, P/h
C =Collecting capacity, kg/h
4. Data Analysis
All the data gathered were analyzed using single factor
experiments arranged in completely randomized design with
three replicates. Analysis of variance (ANOVA) was used to
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
786International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
determine if there were significant differences among
treatment means. The Duncan’s Multiple Range Test (DMRT)
was used to determine which among the means would be
significantly different from each other.
III. R
ESULTS AND
D
ISCUSSIONS
A. Description of Mobile Engine-driven Pneumatic Paddy
Collector
A simple mobile engine-driven pneumatic paddy collector
made of locally available materials using local manufacturing
technology was designed, fabricated and tested for collecting
and bagging of paddy dried on concrete pavement. The mobile
engine-driven pneumatic paddy collector had the following
major components: power transmission system, air mover,
conveyance system, bagging area, and frame. Fig. 2 shows the
actual mobile engine-driven pneumatic paddy collector. The
specification of the machine is presented in Table I.
Fig. 2 Mobile engine-driven pneumatic paddy collector
TABLE
I
S
PECIFICATION OF THE
M
ACHINE
COMPONENTS SPECIFICATIONS
Overall Dimension and weight
Length x Width x Height 1750 x 1450 x 3000 mm
Weight 300 kg
Discharge Cyclone Separator
Inlet opening, L x W 100 x 100 mm
Outlet opening diameter 100 mm
Cylinder dimension, H x D 300 x 600 mm
Inverted cone dimension, h x b 900 x 150 mm
Material 2.3mm mild steel plate for cylinder
and ga. 16 galvanized iron for the
inverted cone
Air Mover
Type Radial flat bladed centrifugal fan
Overall dimension, L x W x H 700 x 300 x 670 mm
Weight 78kgs
Impeller
Type Radial flat blade
Dimension, diameter x
width
380 x 160 mm
No. of rotor 6
Suction side
type Circle
Diameter 200 mm
Discharge side
Type Rectangular
Dimension, Wx h 195 x 200 mm
Material Mild steel, 2.5 mm
Paddy diverter assembly
Type Swing type
Dimension of the inlet, Wx
L
150 x 150 mm
Size of the outlet, W x L 150 x 180 mm
Number of outlet Two
Material Mild Steel plate, 2.3mm
Suction nozzle assembly
Type Flat
Diameter of the
downstream side
80 mm
Size of the pick up side,
HxW
15x 290 mm
Length 1192 mm
Material G. I. sheet, ga 16 for pick up, uPVC,
80mmØ for downstream side, and
G.I. Pipe 20 mm Ø; flat bar, 6 x 25
mm. and G.I. sheet for the handle
Suction line
Type Flexible hose
Siz, Diameter x Length 75 x 3000 mm
Material Vinyl wire reinforced
Wheel
Front
Type Solid rubber tire
Size , Diameter x Width 300 x 70 mm
Material Rubber
Rear
Type Swivel caster
Size, Diameter x width 125 x 100 mm
Material Rubber
Prime mover
Type (Stroke/ignition) 4 stroke
Rated power 14.2 hp
Rated speed 3600 rpm
Cooling system Air cooled
Starting system Rope ranking
Dry weight 49 kg
Machine performance parameters
Collecting capacity 2685.00 kg/h
Collecting Efficiency 99.33%
B. Operating Characteristics of the Machine
1. Collecting Capacity
Table II shows the collecting capacity of the machine as
affected by the rotational speed of air mover shaft. Analysis of
variance revealed that the capacity of the machine as
influenced by the rotational speed of air mover shaft was
highly significant. Comparison among treatment means
revealed that the highest average collecting capacity of the
machine was 2685 kg/h when operated at 4200 rpm. This
collecting capacity was significantly different from 2344.04
and 2192.34 kg/h when operated at 3800 and 4000 rpm
respectively. In normal condition, increasing the rotational
speed of air mover would result to an increased collecting
capacity of the machine. Results revealed that collecting
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
787International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
capacity decreased from 2344.04 to 2192.34 kg/h when
operated from 3800 to 4000 rpm. Familiarization and
consistency in the operation of the machine might be the
reason of decrease in the collecting capacity when the machine
was operated from 3800 to 4000 rpm. On the other hand, one
of the factors that affected collecting capacity was air velocity.
It can be noted that the highest velocity at the inlet of the
suction nozzle was lower than the recommended maximum air
velocity for pneumatic conveying. This means that air velocity
could still be increased to improve the capacity of the
machine.
2. Collecting Efficiency
The computed collecting efficiency of the machine at
varying rotational speed of centrifugal fan shaft is presented in
Table II.
Collecting efficiency exhibited by the machine was 98.99,
98.77, 99.33 % at 3800, 4000, 4200 rpm respectively. Parallel
to the results obtained in the preceding section regarding the
decrease of collecting capacity when operated at 3800 to 4000
rpm, again the same scenario was observed on collecting
efficiency of the machine. Consistency in operating the
suction nozzle might be the reason of a slight decrease in the
collecting efficiency when the machine was operated from
3800 to 4000 rpm.
Analysis of variance revealed that the collecting efficiency
of the machine was not significant as influenced by rotational
speed of air mover shaft. Results of study support the claim of
Walinga incorporated that flat suction nozzle was effective
and efficient in collecting grain left over the floor of silos that
cannot be collected by round suction nozzle[16].
3. Noise Level
Table II shows the mean noise level emitted by the machine
as influenced by rotational speed of centrifugal fan shaft.
Analysis of variance revealed that noise level emitted by the
machine as influenced by varying rotational speed of air
mover shaft was highly significant.
Comparison among treatment means shows that the
machine exhibited statistically comparable noise level of
99.35 and 99.84 dBA operated at 4000 and 4200 rpm
respectively. These are significantly higher from noise level
emitted by the machine with a value of 98.22 dBA when
operated at 3800 rpm. The accepted noise level of any
machine is 92 dBA [3]. High noise level emitted by the
machine could be attributed to the vibration of the centrifugal
fan because of unbalanced blade, engine operated at high
engine speed, loose connection of the diverter valve swing
gate shaft and the sound emitted by the paddy moving around
wall of cyclone separator.
4. Air Velocity at the Inlet of Suction Nozzle
The air velocity at the inlet of suction nozzle of machine as
influenced by varying rotational speed is presented in Table II.
Analysis of variance shows that the machine exhibited
statistically comparable air velocity. An increase of air mover
shaft rotational speed of about 400 rpm and below did not
significantly increase the air velocity at the inlet of the suction
nozzle using the centrifugal fan as air mover.
The maximum air velocity at the inlet of the suction nozzle
of the machine was 13.05 m/s operated at air mover shaft
rotational speed of 4200 rpm. This velocity is higher than the
terminal velocity of paddy of 5.7 m/s [1]. However this is
lower than the recommended velocity of paddy from the
commercial pneumatic conveyors which ranges from 20 – 25
m/s. Result dictates that the velocity could still be increased to
improve the performance of the machine.
5. Fuel Consumption
The fuel consumption of the machine in collecting paddy at
varying rotational speed of the air mover is presented in Table
II. Analysis of variance revealed that fuel consumption of the
machine significantly differed as influenced by varying
rotational speed.
Comparison among means shows that the machine
consumption of 1.43 L/h when operated at 4200 rpm was
statistically comparable to 1.31 L/h when operated at 4000
rpm. Fuel consumption of 1.16 L/h at 3800 rpm was
significantly lower than when operated at 4200 rpm but was
significantly the same when operated at 4000 rpm. Results
revealed that fuel consumption increased as the air mover
shaft rotational speed increased. In four-stroke internal
combustion engines, fuel enters into the cylinder in every two
revolution. Hence, as the rotational speed of the engine shaft
increases, intake stroke increases and fuel consumption
increases.
TABLE
II
O
PERATING
C
HARACTERISTICS OF THE
M
ACHINE
TREATMENT
PARAMETERS
Collectin
g
capacity,
kg/h
Collec
ting
Efficie
ncy, %
Noise
level
dBA
Air
velocity
at the
inlet of
suction
nozzle,
m/s
Fuel
consumpti
on, L/h
T1 (3800 rpm) 2344.04b 98.99 98.22b 10.46 1.16b
T2 (4000 rpm) 2192.34b 98.77 99.35a 12.09 1.31ab
T3 (4200 rpm) 2685.00a 99.33 99.84a 13.05 1.44a
Means with the same letters within columns are not significant at 1% level
using DMRT.
C. Augmented Cracked Grain Percentage
Table III presents the results of augmented cracked grain
percentage as influenced by varying air mover rotational
speed.
Analysis of variance revealed that augmented cracked grain
percentage as affected by varying rotational speed was not
significant. The augmented cracked percentage for a single
pass ranged from 0.33 to 0.67%. This indicates that if the
numbers of passes through the collector are kept to a
minimum, grain damage would not be a problem.
D. Germination Rate
Table III shows the results of germination test observed on
paddy collected by the machine as affected by varying
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
788International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
rotational speed of the air mover shaft. Based on the
laboratory analysis conducted, mean germination rate
observed in seeds collected at 3800, 4000, and 4200rpm were
95.00, 96.67, and 92.67% respectively. These germination
rates are higher than the Philippine standards of 85% and
above.
Analysis of variance revealed that germination of seeds
collected by the machine as influenced by varying rotational
speed of the air mover shaft did not differ significantly.
Germination rate of seeds collected by the machine was
also compared to the control sample. The t-test revealed a non
significant difference in seeds collected by the machine and
the seeds taken from control sample. This means that
germination rate of a paddy collected by the machine was not
affected. Based on the results, the machine could be used by
seed growers to collect paddy during drying.
TABLE
III
A
UGMENTED
C
RACKED
G
RAIN
P
ERCENTAGE AND
G
ERMINATION
R
ATE OF
P
ADDY
TREATMENT PARAMETERS
Augmented cracked grain, % Germination rate, %
T1 (3800 rpm) 0.67 95.00
T2 (4000 rpm) 0.33 96.67
T3 (4200 rpm) 0.67 92.67
E. Simple Cost Analysis
Simple cost analysis was made to guide potential users of
possible benefit projections in using mobile engine-driven
pneumatic paddy collector.
The machine is assumed to be utilized for 400 hours per
annum at four hours of operation per day. Two operators are
required to operate the machine, one is in-charge in bagging at
the bagging section and in pushing the machine, and the
second is in-charge in moving the suction nozzle over the
paddy during collecting operation.
The total cost of the machine was P62, 829.25. Fixed cost
of collecting paddy using the machine annually was P 20,
424.27 while variable cost was P73, 828.00. The cost of
collecting paddy using the mobile engine-driven pneumatic
paddy collector was 0.07 P/kg (3.50 P/cavan) while the
custom rate of collecting paddy was 0.11 P/kg (45.83 % of
prevailing sun drying cost, 12.00 P/cavan = 5.50 P/cavan).
The break-even point was 510,606.75 kg/yr (P 56, 166.74).
Utilizing the machine for 400 hours per year will generate an
income of P23, 887.73. The projected time needed to recover
the cost of the machine based on 2685 kg/h collecting capacity
and custom rate of 0.11 P/kg was 2.63 year (Fig. 3).
Collecting cost, php/kg
Fig. 3 Determining the break even point using the machine
IV. S
UMMARY
,
C
ONCLUSIONS AND
R
ECOMMENDATIONS
A. Summary and Conclusions
This study was conducted to design, fabricate, and evaluate
the performance of mobile engine pneumatic paddy collector.
It aimed to evaluate the operating characteristic of the
machine, evaluate the quality of grain collected in terms of
augmented crack grain percentage and germination rate, and
perform simple cost analysis.
The machine was tested at varying rotational speed of air
mover shaft (T1: 3800rpm, T2: 4000 rpm, T3: 4200 rpm) with
three replicates arranged in completely randomized design.
Analysis of variance (ANOVA) was used to determine if there
were significant differences among means. Duncan’s Multiple
Range Test (DMRT) was used to determine which among the
means would be significantly different from each other.
The mobile engine-driven pneumatic paddy collector had
the following major components: power transmission system,
air mover, conveyance system, bagging area, and frame.
Results of the performance test showed that the mobile
engine-driven pneumatic paddy collector had a mean
collecting capacity of 2685.00 kg/h when operated at air
mover rotational speed of 4200 rpm having a collecting
efficiency of 99.33 percent. The noise level produced by the
machine significantly increased as the rotational speed of air
mover shaft increased. The maximum air velocity at the inlet
of the suction nozzle of the machine was 13.05 m/s at 4200
rpm. The fuel consumption of the machine significantly
increased from 1.16 to 1.43 L/h from 3800 to 4200 rpm.
The average augmented cracked grain percentage ranging
from 0.33 to 0.67 % did not differ from each other as affected
by varying rotational speed of the air mover. The germination
rate was statistically comparable at any rotational speed of air
mover shaft.
The machine entailed an investment cost of P 62, 829.25;
break-even point of 510,606.75 kg/yr (P 56,166.74); annual
generated income of P 23, 887.73 at a collecting cost of 0.11
P/kg. The projected time needed to recover cost of the
machine based on 2685 kg/h collecting capacity was 2.63
year.
Custom rate ,
Php/kg=0.11
BEP = 510,606.7
5
kg/yr
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
789International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
B. Recommendations
To further enhance the performance of the pneumatic paddy
collector, the following are recommended:
1. Replace the check valve by rotary valve to unload
continuously the rice paddy inside the cyclone separator
during collecting operation. This would lessen the
unloading time during operation.
2. Reduce to minimum the total height of the cyclone
separator following the recommended typical dimension
of cyclone [15]. This could increase the collecting
capacity of the machine because of the decrease in
collecting height.
3. Transfer the clutch near the operator in order to reduce the
time of operation.
4. Discharge cyclone separator could be provided at the
discharge outlet of the centrifugal fan to collect dust and
rice hull coming from the said outlet.
5. Provide near the bagging section an open box holder good
for 100 sacks.
6. Provide a transmission system to utilize some power from
the prime mover to move the machine. This could lessen
the work of operator in-charge of pushing the machine
during collecting operation.
7. Reduce engine speed using pulley combination, and
provide spring or shock absorber on the wheel the
machine. This would reduce the vibration of the machine.
8. Conduct a study on design of suction nozzle that
effectively and efficiently collect paddy spread on a
concrete pavement. A wider nozzle could be used; the
upstream portion of the nozzle of scoop (Panake) type
which could collect the grain by pushing the nozzle until
it reaches the downstream side of the nozzle in which the
velocity of air is high enough to suck the grain. The
nozzle could be attached to the pneumatic paddy collector
in order to reduce labor during operation.
9. Conduct a study to assess the performance of pneumatic
paddy collector to unload the rice paddy on flatbed dryers.
This could maximize the utilization of the machine even
in rainy season when sun drying on pavement would not
be possible.
APPENDIX
TABLE A.I
D
IFFERENT
F
ORMULA
U
SED IN
C
OST
A
NALYSIS
PARAMETERS FORMULA
Investment Cost, P IC
Salvage Value, P SV 10% IC
Depreciation, P/yr D (IC-SV)/EL (EL: Economic life
span, yrs)
Interest on investment, P/yr I
, (i: interest rate, decimal)
Housing, Taxes & Insurance,
P/yr
HIT 5%IC
Fixed Cost, P/yr Fc D+I+HIT
Variable Cost, Php/yr Vc
Cf + Cl + Rm + Clu (Cf: Cost of
fuel, P/yr; Cl: Labor Cost, P/yr;
Rm: Repair and Maintenance
(5%IC/100h use), P/yr; Clu:
Lubricant cost(15%Cf), P/yr)
Total collecting cost, P/yr Tc Fc +Vc
Collecting Cost, P/kg Cc
Vc/C*T (C: Collecting capacity of
the machine, kg/h; T: Annual
operation, h)
Break-even point, kg/yr BEP Fc/(Cr-Cc) (Cr: Custom rate,
Php/kg)
Net income generated, P/yr NI C*Cr-Tc
Payback period, yr PBP IC/NI
TABLE A.II
A
SSUMPTIONS
U
SED IN THE
D
ETERMINATION OF
A
NNUAL
C
OST
C
HARGES
ITEMS ASSUMPTIONS
Investment cost (IC), Php 62,892.25
Useful life(n)
a
, yrs
Centrifugal Fan 5
Cyclone separators, diverter valve, frames, suction
nozzle,
bagging section and frames
5
Engine 10
Collecting Capacity, kg/h 2685
Custom rate, Php/kg (Php/bag)
f
0.11 (5.50)
Fuel Consumption, L/h 1.43
Interest rate (i),%/year
b
21
Taxes, insurance and shelter, Php (5% IC)
a
3,144.61
Repair and maintenance, Php (5%IC/100h use)
a
12,578.45
Operating period
e
, h/d 4
Number of working
e
, days/a 100
Hours of operation/a
e
400
Number of operators
e
2
Labor cost
c
, PhP/ /hr 37.5
Cost of diesel fuel
d
, Php/L (Feb , 2013) 47.50
Lubricants
a
15% of fuel cost
a
Depreciation, salvage value, repair and maintenance, tax, insurance and
shelter, and lubricants computation and assumed useful life
[
4
]
b
Prevailing bank interest rate on agricultural loans
[
14
]
c
Computation of interest on investment and assumed labor cost
[
11
]
d
Cost of diesel fuel at Bayombong, Nueva Vizcaya dated February , 2013
e
The machine was assumed to be used in 400 hours per annum or
equivalent to 100 days per year at four hours of operation per day. Two
operators is required to operate the machine; one is in-charge in bagging at the
bagging section and pushing the machine during operation, and the second is
in-charge in moving the suction nozzle assembly over the paddy during
collection operation
f
The custom rate was based on prevailing sundrying cost of Php
12.00/bag, (Spreading and mixing, Php3.50/bag;
Piling and bagging (custom
rate) , Php5.50/bag
; Sewing and hauling, Php3.00/bag)
World Academy of Science, Engineering and Technology
International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering Vol:7, No:8, 2013
790International Scholarly and Scientific Research & Innovation 7(8) 2013 scholar.waset.org/1999.1/16170
International Science Index, Agricultural and Biosystems Engineering Vol:7, No:8, 2013 waset.org/Publication/16170
TABLE A.III
B
ILL OF
M
ATERIALS AND
O
THER
R
ELATED
C
OST
PARTICULARS SPECIFICATION QTY UNIT
COST
TOTAL
COST
Supplies and materials
V belt B-85 2 330.00 660.00
Mild steel plate 2.3mm 2m² 846.00 1,692.00
Angle bar ¼ “ 1 ½” x 6.0m 3 795.00 2,385.00
Angle bar 1/4 ‘ x 1” 8m 85.00 680.00
Flat bar ¼” x 1” x 6m 1 265.00 265.00
Round bar, plain 12mmØ x 3 m 1 110.00 110.00
Square bar 12mm 4m 20.00 80.00
Bar, channel 3” x 6.0m 1 1325.0 1,325.00
Pipe, G. I. S40, 1 ¼”Ø x
6.0m 1 870.00 870.00
Pipe, G. I. S20, ¾”Ø 1.5 ft 87.50 87.50
Pipe, Pvc 3ӯ x 1.0m 1 106.00 106.00
Pipe, B. I. 3ӯ x 3.0m 1 700.00 700.00
Elbow, G. I. 3” 2 230.00 460.00
Coupling, G. I. 3” 1 124.00 124.00
Solid shaft 1ӯ 2ft 120.00 240.00
G. I. sheet #16 2.4 m² 465.00 1,116.00
Bolt with nut and
Washer 5/8" x 2" 4 45.00 180.00
Bolt with nut and
washer: 7/16 x 2” 4 25,00 100.00
Bolt with nut and
Washer: 5/16" x 1" 28 6.00 168.00
Wheel, swivel caster
wheel 5”Ø x 2 ½” 2 700.00 1,400.00
Wheel, solid rubber, 12”Ø x 2” 2 1,000.0 2,000.00
Wheel: plastic 1 1/2"Ø 2 24.00 48.00
Vinyl, wire
reinforced flexible
hose
3ӯ 3m 250.00 750.00
Wire mesh 1.0m x 1.2 1 150.00 150.00
Hose clamp, heavy
duty 4ӯ 5 20.00 100.00
Welding rod E6013 10kg 65.00 650.00
Red oxide primer
(Boysen)
1L 109.00 109.00
Paint: QDE
(Boysen) yellow 1L 162.00 162.00
Paint: QDE
(Boysen) black 1L 116.00 116.00
Hack saw 24TPI 5 50.00 250.00
Steel Cutting Disk #4 5 80.00 400.00
Grinding stone #4 3 80.00 240.00
Paint brush: 2" 1 25.00 25.00
SUB-TOTAL 17,792.25
Equipment
Diesel engine 14hp, air-cooled 1 14,500 14,500.00
Centrifugal blower 1 20,000 20,000.00
SUB-TOTAL 34,500.00
Labor Cost for the fabrication ( 25MD @ Php400/MD) 10,000.00
Labor Cost for the threading of solid shaft and bending of push
handle G . I. pipe 600.00
GRAND TOTAL 62,892.25
TABLE A.IV
S
IMPLE
C
OST
A
NALYSIS
PARTICULARS
Investment Cost, P 62,892.25
Useful life (L), yrs
Centrifugal Fan 5
Cyclone separators, diverter valve, frames, suction
nozzle, bagging section and frames 5
Engine 10
Salvage Value, P 6,289.22
Capacity of the Machine, kg/h 2685.00
Diesel fuel consumption rate, L/h 1.43
Price of Diesel, P/L 47.50
Number of operators required 2
Labor rate for operator 37.50
Interest rate(i), decimal 0.21
Fixed Cost:
Depreciation, P/yr
10,015.61
Centrifugal Fan 3,600.00
Cyclone separators, diverter valve, frames, suction
nozzle,
bagging section and frames
5,110.61
Engine 1,305.00
Interest on investment, P/yr 7264.05
Tax, Insurance, and Shelter, P/yr 3144.61
TOTAL FIXED COST 20,424.27
Variable Cost:
Diesel fuel, P/h 67.93
Lubricants, P/h 10.19
Repair and Maintenance, P/h 31.45
Labor Cost, P/h 75.00
TOTAL VARIABLE COST, P/h 184.57
Cost of collecting, P/yr 94,252.27
Cost of collecting; P/kg (P/cav) 0.07 (3.50)
Custom rate of collecting, P/kg (P/cav) 0.11 (5.50)
Annual net income generated, P 23,887.73
Payback Period, yrs 2.63
Break-even point, kg/yr 510,606.75
A
CKNOWLEDGMENT
Authors express their sincere thanks to the Engineering
Research for Development and Technology scholarship
program of Department of Science and Technology (ERDT-
DOST) for pro-viding all the necessary guidance, funds and
facilities during the research project.
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