Design development of continuous type coconut splitter

Abstract

Coconut (Cocous nucifera L.) is one of the most prominent commercial crops in tropical and is usually referred as “tree of heaven”. The seed or the fruit of the coconut palm, which is also referred as coconut must be dehusked and split before using for various purposes. Although there are different techniques and tools for splitting or cracking open the mature coconut, there is no suitable machine for continuous splitting of nut with provision for collecting the coconut water hygienically. Development of such machine requires a detailed investigation on the physical and engineering properties of coconut. Splitting energy and splitting force required are certain other vital information necessary for the design. Hence this study was undertaken for investigating the design parameters for the development of a continuous coconut splitting machine. The physical properties of the coconut were determined using standard procedures and the splitting energy requirement was determined using an impact test apparatus. The maximum splitting force was then calculated from the splitting energy. Based on the maximum splitting force and physical properties, the design parameters were evolved, and a machine was designed and developed. The trails of the machine were then conducted to evaluate the performance in comparison with the conventional splitting method. The average major diameter of the coconuts were obtained as 117.24 mm with standard deviation of 9.00 mm. The average minor diameter of the coconuts were recorded as 97.09 mm with standard deviation of 5.57 mm. The average intermediate diameter of the coconuts were found to be 93.29 mm with a standard deviation of 4.59 mm. The average weight of the coconuts were observed as 579.99 g with a standard deviation of 104.56 g. The average roundness of the coconuts were measured and found to be 0.65 95 with a standard deviation of 0.10. The average sphericity of the coconuts was 0.83 with a standard deviation of 0.05. The average volume of the coconuts were 556.20 cm3 with a standard deviation of 64.07 cm3 . The average density was 1.04 g cm-3 with a standard deviation of 0.14 g cm-3 . The maximum splitting energy and force needed to split coconuts were recorded as 35.84 J and 609.25 N respectively. The machine was designed to split coconut by impact force, by making an impact tool hitting the nut positioned in continuously rotating feeder. The impact tool held in position by a tension spring, was actuated by a cam, which in turn receives power from an electric motor of 0.746 kW. Speed reduction gear box, chain and sprockets were used for transmitting the power from motor to the impact tool. Water collecting trough and strainer were fixed beneath the feeder and impact tool. The performance evaluation of continuous type coconut splitter was conducted, and it was found that time require to split the coconut is 5 seconds. The average splitting efficiency of the machine was obtained as 85.51 per cent with a standard deviation of 8.25. The output capacity of the developed machine was 372.4 kg h -1 . The total number of coconuts split per hour was obtained as 720. The efficiency of the machine was obtained as 85.71 per cent. Keywords: Coconut, Splitting energy, Splitting force, Impact tool, splitting efficiency, machine output capacity, efficiency of the machine.