Influence of Load and Stirrer Type on Current, Temperature and Revolution Per Minute (RPM) Developed on a Locally Fabricated Mixer
A mixer was designed and constructed on angle iron frame 450400950 mm (LWH), witha spiral(A) and non spiral stirrer(B) 35010.5mm(L) as impeller and powered by a 2.7kwgenerating set through 0.374 kw(0.5Hp) a single phase electric motor with variable speed control.The mixer was run on equal mass of our, sand, garri, water and air as load at 5 dierentloading speeds at one instant ,then the speed kept constant and evaluated on 1 to 5 kg of sand.The revolution per minute/temperature attained in the motor and current developed per eachsample were measured by a tachometer, analogue temperature sensor and 266 clamp ammeters.The data on load were regressed against rpm, while a bill of quantity performed on the mixerResult show that the mixer is capable of mixing the materials at various speeds (rpm) of 1280,1212, 1140, 1035 and 945 for stirrer A and 1302, 1211, 1152, 1046 and 961 for stirrer B, asthe load increased from 1-5kg for water /our mixture. An estimated speed of 1275 rpm for 5kg our at temperature of 41.4 and current of 11.12amp was recorded. Regression analysis showeda deceleration of -0.966 between loads and speed (rpm) and indicated that for every increase by 1kg of load, speed (rpm) reduces by 84.5 and 85.5 for A and B stirrers, which ts the linear model.Economically, small scale processor can aord to run these mixers which was estimated to costtwenty eight thousand naira (28,000) or $150 equivalent.
Keywords: mixer, stirrer type, speed, our, small scale