Development of Sawdust - Compressing Machine for Mushroom Culture

Abstract

The study was to develop a sawdus tcompressing machine (SCM) for mushroom culture in plastic bag. The methodology consisted of technical design. construction, testing and economic and engineering evaluation. the developed SCM was semi-automatic, weighed 38 kg and 48 cm wide by 53 cm long by 102 cm. high. Its operation was featured by 1/3-HP, 220 V 50 HZ electric motor drivinga 50:1 reduction gear and an eccentric compression mechanism, causing 1/2 inch steel cylinder moving up the plastic bag. Testing SCM in comparison with a man showed that SCM could compress sawdust at the rate of 576 and 112 bags/hr. respectively while with rice straw the machine and the man could achieve compression the rate of 372 and 172 bag/hr. respectively. Density of the compressed sawdust was averagely 0.64 and 0.73 gm/cc respectively with SCM and a man. With rice straw the density made by SCM and the man was 0.36 and 0.38 gm/cc The compressed sawdust and rice straw both by the total cost varied increasingly as production quantity and operation days. For 50 days of operation and service rate of 14 baht/100 bags, return rate would be 93.4% which was greater than interest rate of opportunity cost about 12% per year. Investment recovery time would be 1 year and break even point corresponds 68,093 bags.