|Title of Invention||
DESIGN AND DEVELOPMENT OF A COCONUT DE-SHELLING MACHINE
|Abstract||Traditionally after partial drying of split coconut, the kernel and copra is separated using a traditional wooden mallet by taking the individual cups in hand. To over come this problem, a power operated coconut de-shelling machine was designed and developed. The capacity of the machine was 400 half cups per batch. The optimum average moisture content for maximum de-shelling efficiency (92.16 %) was 35 % d.b. The optimum speed of the de-shelling machine was 10 RPM and the time taken for de-shelling was 4 minutes per batch. Cost of the machine was Rs. 27,100 and the cost of de-shelling 1000 nuts was Rs.53.00.|
|Full Text||3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed. Traditionally after partial drying of split coconut, the kernel and copra is separated using a traditional wooden mallet by taking the individual cups in hand. To over come this problem, a power operated coconut de-shelling machine was designed and developed. The design drawing of the de-shelling machine is given in Fig.l. The dimensions of the cylindrical de-shelling chamber were calculated as 90 cm diameter and 115 cm length to hold 200 split coconuts at an average moisture content of 35 % d.b. based on bulk density and porosity values. Loading and unloading of partially dried copra was done manually. Three flights having 29 x 22 cm cross section running throughout the length of the drying chamber were fixed inside the de-shelling chamber at a distance separated by 120 . The lip angle of the flight was fixed
at 70 based on preliminary tests conducted, so that the nuts can fall freely from the flight uniformly in the de-shelling chamber.
The horse power required to rotate the cylindrical de-shelling chamber at 10 RPM was calculated as 3.0. To achieve the required low speed a reduction gear box with a set of pulleys were fixed. A 3.0 phase 3 hp electric motor was coupled to rotate the de-shelling chamber at the desired RPM.
Fabrication of major components
The main axle was fabricated using 60 mm (φ OD) mild steel shaft of 1.75 m
length which was provided with 2 bearings at the ends and one pulley to rotate the de-shelling chamber freely.
Main support frame
The main support frame was fabricated using 75 x75 x8 mm mild steel angle to withstand the load of the de-shelling chamber and copra. The height of the de-shelling chamber was fixed at 110 cm for easy loading and unloading of partially dried copra.
Method of operation
Partially dried copra was loaded in to the de-shelling chamber manually. The capacity of the de-shelling chamber was 400 partially dried half cups. When the average moisture content of the copra reached 35 % d.b. the door of the de-shelling chamber were opened and copra was loaded. The de-shelling chamber was allowed to rotate at a speed of 10 RPM for different periods and the de-shelling efficiency was calculated. The cost of de-shelling machine was worked out to be Rs. 27,100.00. The optimum number of rotations was 40. The deshelling time based on the speed of the reduction gear output was four minutes.
The design details are given below.
The dimensions of the de-shelling machine were determined based on the bulk density of
split coconuts for 200 nuts capacity.
Bulk density of coconut at a moisture content of 35 % d.b = 380.593
Approximate weight of 200 split nuts, m = 84.26 Kg
Let the length of the de-shelling machine be = 115 cm
(Length has been assumed instead of diameter as diameter is taken from experiments
conducted to include the height of fall for separation)
The radius of the de - shelling chamber can be determined by using the equation
.-. hp = 2.90
Hence, a 3 hose power motor (standard size) that was available in the market was coupled to the reduction gear box unit so as to rotate the drum at the optimized speed of l0 RPM
The de-shelling machine was tested for its performance evaluation with partially dried copra having moisture content in the range of 66.4 to 25.7 % d.b. and it was found that the optimum average moisture content for de-shelling was 35 % d.b. At 35 % (d.b.) moisture content the deshelling efficiency was 82.5 %. Five replicate tests were conducted for each moisture content and the average values were used for calculations. The increase in de-shelling efficiency with respect to decrease in moisture content is given in Fig. 2.
The effect of number of rotations on the de-shelling efficiency were explored by keeping the moisture content constant at 35 % d.b. Nuts (400 half cups) were loaded manually and the machine was operated. It was observed that after 40 rotations practically there was no further increase in the efficiency of de-shelling (Fig. 3). On careful examination it was also observed that unless the coconuts are of the same maturity the efficiency will not increase due to uneven moisture content in the partially dried copra. At 30 rotations the efficiency of the machine was 85.64 %, at 40 rotations the efficiency was and 92.16 % and this further increased to 93.5 % by rotating 50 and 60 times. Hence the optimum number of rotations was fixed as 40. Thus the deshelling time based on the speed of the reduction gear output was four minutes. The increase in deshelling efficiency with respect to number of rotations is given
|Indian Patent Application Number||672/CHE/2006|
|PG Journal Number||20/2009|
|Date of Filing||12-Apr-2006|
|Name of Patentee||INDIAN COUNCIL OF AGRICULTURAL RESEARCH|
|Applicant Address||Director, Central Plantation Crops Research Institute, Kasaragod, Kerala 671 124,|
|PCT International Classification Number||A23N 5/00|
|PCT International Application Number||N/A|
|PCT International Filing date|