A rice huller or rice husker is an agricultural machine used to automate the process of removing the chaff and the outer husks of rice grain.Throughout history, there have been numerous techniques to hull rice.Traditionally, it would be pounded using some form of mortar and pestle.Machinery has now been developed to hull and polish the rice.These machines are most widely developed and used throughout Asia where the most popular type is the Engelberg huller designed by Evaristo Conrado Engelberg and first patented in 1885. The Engelberg huller uses steel rollers to remove the husk.Other types of huller include the disk or cono huller which uses an abrasive rotating disk to first remove the husk before passing the grain to conical rollers which polish it.Rubber rollers may be used to reduce the amount of breakage of the grains, so increasing the yield of the best quality head rice, but the rubber rollers tend to require frequent replacement, which can be a significant drawback. Source: en.wikipedia.org