Design, fabrication, and comparative evaluation of plant power shredder

Abstract

Fresh organic materials have to be shredded into smaller sizes to increase their decomposition rate. Hence, a plant shredder is necessary. This study illustrates the importance of traditional or local knowledge to agriculture and natural resource management by providing households with adaptive strategies. A plant shredding machine known as “Plant Power Shredder (PPS)” suitable for village-scale use was developed following the design criteria such as: portability, affordability, efficiency and versatility. The machine is 1.5mL×1.05m W×1.10m H, weighs 150kg and costs PHP75,000 (including 7hp Diesel engine). It is mounted in an angular bar framing fitted with 2 free-wheeling wheels to be pulled by a hand tractor. The prototype used combination of shear and impact forces through the combination of radially mounted blades and hammer-members. Comparative evaluation of PPS was done with the RUMVD35000-16 and RUMVD35000-14 in terms of capacity, efficiency, fuel consumption, power-output ratio, sizes of shredded materials, percent decomposition of shredded output and break-even cost of each machine. Shredding was done on rice straw (RC 216), kakawate leaves and branches and dried coconut husk at three replications. Results showed that PPS has the highest efficiency of 95.71%, lowest fuel cost of PHP57.17 per hour and PHP0.15 per kg, highest power to output ratio of 0.014hp per kg and lowest break even cost of PHP0.68 per kg. RU 14 has the highest capacity of 471.90kg per hour and has the greatest percentage of short-size shredded material of 70.94 %.