Investigation of the effects of variable beater speeds on juice yield, extraction efficiency and extraction loss of a fruit pulp extractor
Keywords:Pulp Extraction, variable frequency drive, beater shaft, perforated cylinder, extraction loss.
An experimental study on the effects of variable beater speeds on juice yield, extraction efficiency and extraction loss of a fruit pulp extractor was conducted. The machine was designed to operate on the principle of centrifugal and shear squeezing force exerted through blades with incorporated teeth. It consists of a mild steel tapered frame, beater shaft with three blades having teeth, sieve mesh cylinder; pulp collection chamber, hopper, discharge channel. The machine is run by a set of pulleys and AC induction motor using variable frequency drive. Three mango varieties i.e. Sindhari, Chaunsa and Langra at two sieve mesh sizes 700 micron and 400 micron, two levels of clearance 35mm and 25 mm between sieve mesh cylinder and beater were tested at two different speeds i.e. 300 rpm and 600 rpm. 5 kg of mangoes for each experiment were used and 7 minutes 30 seconds time was noted for each operation. The machine was evaluated in accordance with standard evaluation methods. The time taken for juice extraction, mass of juice extracted, mass of fruits and residual wastes were recorded and used to obtain the performance indicators considered. It was recorded that pulp extractor on all the testing combinations gave the highest juice yield, highest extraction efficiency and lowest extraction loss at high speed i.e. 600 rpm and minimum juice yield, minimum extraction efficiency and highest extraction loss at low speed i.e. 300 rpm.