A study shows that the type of ricemill being used in countryside is vital towards achieving the government’s food sufficiency program, It also shows the relevance of the type of huller used by the ricemill on particular grains, Japonica varieties and the long grains the Indica varieties.
Various scientific papers reveal that the rubber roll type of huller will perform better with Indica varieties of 70%-75% (which incidentally was the majority of varieties produced in the country) than it does with short grains, Japonica with milling recovery of 60%-67% only.
Studies show that long grains are appropriate for impeller type of rice mill. The impeller type of huller with the same performance as the rubber roll machine, works for both long and short grains samples.
The rubber roll-type huller also proved to have higher system cracked ratio compared to impeller husker for both short and long grains samples. This was attributed to the shearing force when rough rice passes through the two rubber rolls operating at different speeds. This tends to stretch the grain between the rolls.
Experts explain that a ricemill is composed of the huller which removes the husk and the polisher which removes the rice bran.
. Hullers may be of three types, stone disk, rubber roll, and impeller. The stone disk huller is a standard component of the conventional “cono” rice mill that consists of two circulars discs laid flat one on top of the other with their grinding surfaces facing each other. The rubber roll huller consists of a pair of rubber rollers mounted on a horizontal shaft and designed so that one roller rotates clockwise and the other counterclockwise.
The impeller huller is designed based on centrifugal and Coriolis forces, whereby the paddy is thrown against the liner part of the impeller housing.
The only available ricemills in the country are the stone disk, commonly known as “kiskisan” and the rubber roll popularly known as “cono”. The widespread use of inefficient rice mill like kiskisan, a stone disk huller, could limit the available supply of rice in the country due to its low milling recovery.
At the average, the kiskisan has a milling efficiency of 50-55% compared to single pass rubber-roll cono rice mill that provides an average milling recovery of 60-63% or the multi-pass rubber-roll’s milling recovery of 63-65%.
As such, a 100-kg dried paddy that passes through a kiskisan could produce only a 50-55 kg of milled rice compared with the 60-67 kg recovery of rubber-roll type rice mills.While the rubber-roller type “cono” rice mill is very popular in the Philippines because of its good milling efficiency, this type of rice mill requires higher investment and operating cost, higher power requirement and regular replacement of rubber rolls.
With the study, experts conclude that one potential approach in improving the current milling system in the Philippines is the development of impeller type rice mill given its relatively simple hulling mechanism and good performance to long grain.
The first prototype of commercial model of impeller-type ricemill as fabricated proved to be easy to install, requires a small working space, has a lower maintenance and operating cost, and a higher milling capacity, among other advantages. The commercial unit will be field and pilot tested in major rice-producing areas in the country.
The study on the impeller compact ricemill is one of the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD’s) initiatives to improve the state of R&D in the agriculture, aquatic and natural resources sectors.(PSciJourn MegaManila).