Development and Evaluation of a Helical Ribbon-Type Mixer for Mushroom Substrate

Abstract

Manual substrate mixing for mushroom production such as rice straws, sawdust, and banana leaves is laborious and time-consuming. Substrates need to be thoroughly mixed to produce mushrooms of good quality. This study was done to design, fabricate, and evaluate the performance of a helical ribbon-type mixer. The performance of the ribbon-type mixer was evaluated in terms of the mixing capacity and mixing efficiency. Loading weight (5kg, 10kg, and 15kg) and operating speed (11-15rpm, 16-20rpm, and 21-25rpm) of the machine were used as the performance parameters. Analysis of Variance (ANOVA) for Factorial Experiment in Completely Randomized Design (CRD) was used to analyze the results while comparison among treatment means was tested at 5% level of significance using Duncan's Multiple Range Test (DMRT). Results revealed that the highest machine capacity of 226.67 kg/hr was attained at a loading weight of 15kg and an operating speed of 21-25rpm. Maximum mixing efficiency (95.27%) was achieved with the combination of 15 kg loading weight and an operating speed of 11-15 rpm. The initial investment in fabricating the substrate mixer for mushroom production was Php 21, 713. Operating the substrate mixer for mushroom production had a projected annual cost of Php 3,655.475.  Break – even weight was 91,795.24 kg of substrates per year at a custom rate of Php 0.35 per kilogram.