DESIGN, CONSTRUCTION AND PERFORMANCE EVALUATION OF ENGINE DRIVEN WARQE/ENSET (Enset ventricosum) DECORTICATOR

Abstract

Warqe/enset processing is carried out dominantly by rural women using traditional tools such as bamboo scraper, serrated wooden tool and metal knife where losses in quality and quantity are exceptionally high. Above all, the traditional way of warqe/enset processing causes to much physically drudgery among the rural women. In an effort to alleviate the problem, an engine driven warqe/enset decorticating machine was designed, constructed, tested and evaluated. The performance evaluation of the machine was made in terms decorticating capacity, decorticating efficiency, pulp loss and fuel consumption. The performance evaluation was carried out at three levels of drum speeds (850, 950 and 1050 rpm), concave clearances (1, 3 and 6 mm) and feeding rates (0.037, 0.056 and 0.074 kg/s), these are based on the feeding rates of 1.00, 1.50 and 2.00 kg/27s to determine the optimum combination of the same. The experimental design laid was factorial, in split-split plot. Maximum decorticating capacity of 255.38 kg/hr. was obtained at drum speed of 850 rpm, concave clearance of 1 mm and feeding rate of 0.074 kg/s. The decorticating efficiency and percentage un-decorticated pulp highly depended on concave clearance rather than other factors. Maximum decorticating efficiency 98.97% was achieved at drum beater speed of 850 rpm and concave clearance of 1mm. The production cost of the decorticator was found to be 28,322.00 Birr. The total operation cost of the decorticator estimated to be 48,925.38 Birr and the payback period and benefit cost ratio of the prototype decorticating machine were estimated to be 0.90 year and 1.64, respectively