Design, Construction And Performance Evaluation Of A Magnetic Sieve Grinding Machine

ABSTRACT

Technology of milling and grinding machine is one of the simplest methods

of processing agricultural raw materials alternative to the traditional

methods of grain/tuber processing using stone, mortar and pestle. However,

machines constructed using metal plates results in tearing and wearing

away of the materials of construction. The effect of this is the contamination

of the processed foodstuff. This is known to have negative health

implications when accumulated and consumed in large quantities. In this

study a magnetic sieve grinding machine was designed, constructed and the

performance evaluation undertaken in order to remove the toxic metal filing

contaminants that cause the health hazard in food when consumed. The

machine consists of a 0.04m3 capacity hopper, a machine housing, a blower

with 13.35m/s air speed, a cyclone, set of hammers that effect the size

reduction of the materials been fed, 12cm width rotor pulley, a shaft of

50cm in length and a magnetic sieve that separate metal filings from the

grounded food stuff. The machine is powered by a 5.96 kW diesel engine.

Performance evaluation showed that 10.5g of the machine parts were worn

out after 10hours of grinding. The throughput capacity and the efficiency of

the machine are 600kg/hr and 87.5% respectively. Thus, from the results of

the investigation, the objectives of the study were achieved. The use of the

magnetic sieve grinding machine by local food processors will help reduce

the rate of food contaminations during post harvest processing of

biomaterials and also safeguard people’s health through food security.