Study on Separating by Shape Using Test Rice Grader (Part 1)
Analysis of Separating Mechanism for Indent Cylinder Type
1979 Volume 41 Issue 3 Pages 455-461
Details
1979 Volume 41 Issue 3 Pages 455-461
A study was carried out to explain the mechanisms of the broken rice separator of indent cylinder type. The results obtained were as follows:
1. The separating by indent cylinder type consists of two different mechanisms: the first mechanism is similar to that of a screen, and the second mechanism is that of a separator in which the grain length is a separating factor.
2. The probability P that the grains enter into the hopper equals the probability PA of grains caught by the indent parts multiplied by the probability PB that the grains can enter the hopper. This relationship is expressed in Equation (1).
3. The probability PA for the first mechanism is expressed in Equation (7).
4. In case of the second mechanism, the grains (mostly whole grains) are rolled and failed at the angle α as expressed in Equation (23) when δ<μ. The grains (mostly broken grains) are slided and failed at the angle α' as expressed in Equation (25) when δ>μ. Where μ is the coefficient of static friction and δ is expressed in Equation (20) and in Fig. 7.
5. In order to get a better separation of whole and broken rice, the angle of falling point of broken rice should be greater than that of whole rice. The center of gravity and the friction coefficient are important factors in determining this angle. This relationship is expressed in Fig. 8.
6. Besides the grain length, there are also many other physical properties which have erects on the probability PB of the second mechanism. The values of PB are determined from the distribution of the physical properties and hopper angle, and expressed in Equation (27).
