Theoretical analysis of tuber movement during mechanical peeling of cassava

Abstract

Cassava Peeling has been identified as the only un-mechanized unit operation in cassava production which has constituted global challenge in twenty-first century despite an ever-increasing demand for the crop. As at today, cassava peeling is still largely carried out manually, it makes the process to be slow, labour intensive, arduous in nature, and low productivity. This research work aimed to analyse and model tuber movement during mechanical peeling. Preliminary experiment was carried out on newly harvested tubers graded into sizes and sliced at 50 to 100 mm using peeling machine developed earlier on the basis of this principle. The data collected were used to validate the model. Model developed adequately analyses the concept of tuber movement during peeling and also predicts peel shear stress, 6.142 N/mm 2 and effective peeling time, 9.5-12.0 s at velocity of conveyance, 1-5 m/s. This is therefore considered as reliable tool for further development and improvement of cassava peeling system.

A review of mechanical cassava peeling and its adoption by processors

“…Generally, throughput capacity has been reported to increase with an increase in both speed of operation and tuber loading (Adekunle et al, 2018;Alhassan et al, 2018;Olukunle and Akinnuli, 2012). Jimoh et al (2016) also reported that throughput capacity increased with an increase in speed and weight of cassava peeled for both serrated and smooth-edged knife peeling machines. The reason for this pattern is that, since throughput capacity is a function of the weight of cassava and peeling time, increasing the tuber loading or reducing the peeling time (which can be achieved by increasing the speed, especially in continuous peelers) will increase the throughput capacity (Jimoh et al, 2016).…”

“…Jimoh et al (2016) also reported that throughput capacity increased with an increase in speed and weight of cassava peeled for both serrated and smooth-edged knife peeling machines. The reason for this pattern is that, since throughput capacity is a function of the weight of cassava and peeling time, increasing the tuber loading or reducing the peeling time (which can be achieved by increasing the speed, especially in continuous peelers) will increase the throughput capacity (Jimoh et al, 2016). Concerning the size of cassava roots, Olukunle and Akinnuli (2012) reported that throughput capacity increases with an increase in size while Jimoh et al (2014) stated that the size of roots is inversely proportional to peeling time (which is inversely proportional to throughput capacity).…”

“…The sizes of cassava used in this study were in the range of 100-310 mm in length. Jimoh et al (2016) again reported that peeling efficiency slightly increased at lower speeds (100 -120 rpm) but decreased at higher speeds between 130 -140 rpm for the smooth-edged cutting tool. For the serrated-edged cutting tool, efficiency increased as speed increased from 140 -160 rpm.…”

“…Some are also designed to allow for the gravitational flow of the cassava during peeling (Pius and Nwigbo, 2017). Again, others have the peeling units designed such that they aid in moving the cassava from the point of feeding to delivery (Jimoh et al, 2016;Ugwu and Ozioko, 2015).…”

“…It was evaluated to have an overall cost of $150 and can be operated and maintained by an individual. Jimoh et al (2016) used dimensional analysis to develop the relationship between machine functional properties and some identified crop and machine variables during mechanical peeling. Figure 8 shows the peeler used in this study.…”