An integral process of rice production is rice milling. And just like in any nation where rice is produced on a large scale, rice milling has been around for a very long time in India. The need for milling arises because paddy cannot be consumed in its raw form and requires suitable rice polisher.
The sequence of operations essentially followed in the milling of rice are: (i) feeding of paddy from gunny bags to the dumping pit, (ii) cleaning of paddy grains, (iii) removal of husk (dehusking) from the paddy, (iv) separation of rice grains from the husk, (v) polishing of rice, (vi) cleaning or separation of rice from bran and (vii) dumping of rice at a place for subsequent collection in gunny bags. For cleaning of paddy, sieve shakers are used. Dehusking is done using rubber roll shellers. For the separation of rice from the husk, a sieve shaker along with a blower is used. The rice is separated from the paddy and broken rice using a compartment separator. Polishing is achieved through a cone-type polishing machine (rice polisher) and the rice is cleaned finally using a sieve shaker along with a blower. The paddy/rice is transferred from one machine to the next using bucket elevators. The sequence of processing machines through which the paddy flows during milling. The dotted lines indicate other optional machines used in various rice mills.
The rice whitener, which determines the quality of processing, is the key milling equipment in the rice processing line. The control of whiteness (degree of milling) and percentage of broken kernels is done by skilled workers who adjust the pressure door in the outlet, according the color, translucent, temperature etc. of the milled rice.