munggo sheller
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8/12/2019 Munggo Sheller
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MUNGGO SHELLER: FOR SMALL SCALE MUNGGO PRODUCTION IN ROMBLON
By: Engr. Virne B. Dalisay, et. al
Faculty, Romblon State University
Chairman, Mechanical Engineering Department, RSU
Machine Technical Description
The Sheller is powered by a 1 horsepower electric motor as a given parameter since it is a
prototype and intended for small capacity. This was based also on design considerations of cost and
portability. The selection of different dimensions of the components and machine elements was based on
the given power capacity of the prime mover, 1-hp motor. The motors power is transmitted through a
belt and pulley transmission system to the shelling and cleaning units of the Sheller.
The shelling unit is composed and made of 9-mm square bar steel teeth welded on a frame
encircling the 1-in. diameter shaft. The 32 pieces, 3-inch teeth length are uniformly welded in a 3-inchdistance at right angle position. The teeth and shelling cover has a 5-mm clearance, slightly lower than the
average pod diameter. The cylinder cover is made up of a semi-circular 18-gage G.I sheet having a radius
of 7.5 inches perpendicular with the horizontal.
The cleaning unit is composed of an oscillating screen and blower assembly. The screen was
selected such that its holes are slightly larger than the munggo kernels. Actual measurement of the kernels
prompted the use of a screen with a inch diameter holes. This screen is attached to a tray where the
kernels and the shells are separated by the reciprocating motion of the tray. The oscillation of the tray was
achieved by attaching the tray in a cam mechanism machined in the shaft which is belt connected with the
shelling cylinder. A blower was included to address the presence of light impurities in the kernels during
the shelling operation. The initial setting for the blower speed was determined by observing the behaviorof the shells, kernels, and light impurities when air passes through them. To modify the air velocity
coming from the blower, the pulley attached to the blower shaft was iteratively chosen such that the
scattering and blower losses are minimized.
Performance Evaluation
The performance parameters determined during the tests include shelling efficiency, shelling
capacity, shelling recovery, input capacity, and total kernel loss. The total kernel loss consists of blower,
separation, unshelled and scattering losses.
The average shelling efficiency of the two trials of the machine based on the losses is 96.97%. It
measures the capacity of the machine to remove the kernels from the shell. On the other hand, the average
shelling recovery of the machine is 88.98%. It measures the efficiency of the machine when it comes to
the ratio of the cleaned kernel collected from the kernel outlet to the total kernel input of the Sheller.
The average input capacity of the Sheller machine is 113.6 kg/hr, or an equivalent 5 kg dried
munggo shelled in 2.6 minutes. For 1-hectare munggo farm production yielding almost 1100 kgs (1.1 tons
of munggo) can be shelled in at least 9.6 hr of continuous operation of the machine. Payback period is 2.5
years.
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