DOI QR코드

DOI QR Code

Analysis of Broken Rice Separation Efficiency of a Laboratory Indented Cylinder Separator

  • Kim, Myoung Ho (Department of Bio-industrial Machinery Engineering (Institute of Agricultural Science and Technology), Chonbuk National University) ;
  • Park, Seung Je (Department of Bio-industrial Machinery Engineering (Institute of Agricultural Science and Technology), Chonbuk National University)
  • 투고 : 2013.05.08
  • 심사 : 2013.05.22
  • 발행 : 2013.06.01

초록

Purpose: Using a laboratory indented cylinder separator, broken rice separation experiments were conducted and the characteristics of the separation process were studied to provide information for developing a prototype indented cylinder broken rice separator. Methods: Rice (Ilmi variety) milled in a local RPC was used for the experiment. Rice kernels were classified into four groups according to their length l; whole kernels (I > 3.75 mm), semi-whole kernels (2.5 < I < 3.75 mm), broken kernels (1.75 < I < 2.5 mm), and foreign matters (I < 1.75 mm). A laboratory grain cleaner, Labofix '90 (Schmidt AG, Germany) was used for the experiments. Experiments were designed as a $4{\times}4$ factorial arrangement in randomized blocks with three replications. Cylinder rotational speeds (17, 34, 51, 68 rpm) and trough angles (15, 37.5, 60, $82.5^{\circ}$) were the two factors and feed rates (25, 50 kg/h), indent shapes (Us, $S_1$ type), and indent sizes (2.5, 3.75 mm) were treated as the blocks. Two 125 g samples and one 125 g sample were taken at the cylinder outlet and from the trough, respectively. The whole, semi-whole, and broken kernel weight ratio of the samples and feed was determined by a rice sizing device. From these weight ratios, purities, degrees of extraction and coefficient of separation efficiency were calculated. Results: Trough angle, cylinder speed, and their interaction on the coefficient of separation efficiency were statistically significant. Cylinder speed of 17, 34, and 51 rpm made the most effective separation when the trough angle was $15^{\circ}$ or $37.5^{\circ}$, $60^{\circ}$, and $82.5^{\circ}$, respectively. Maximum values of coefficient of separation efficiency were in the range of 60 to 70% except when the indent size was 2.5 mm and were recorded for the combinations of low cylinder speed (17 rpm) with medium trough angle ($37.5^{\circ}$ or $60^{\circ}$). Indent shape did not appear to make any noticeable difference in separation efficiency. Conclusions: Due to the interaction effect, the trough angle needs to be increased appropriately when an increase in cylinder speed is made if a rapid drop of effectiveness of separation should be avoided. In commercial applications, $S_1$ type indents are preferred because of their better manufacturability and easier maintenance. For successful separation of broken kernels, the indent size should be set slightly bigger than the actual sizes of broken kernels: an indent size of 3.0 mm for separating broken kernels shorter than 2.5 mm.

키워드

참고문헌

  1. Anonymous. 2011. Criteria for the grades and protein contents of rice. Korean Ministry for Food, Agriculture, Forestry and Fisheries. Notice No.2011-131 (In Korean).
  2. Choi, H. S. 2005. Korean milling technology for rice quality improvement. Proceedings of the International Symposium on Technologies in High Quality Rice Production 89-123 (In Korean).
  3. Food Agency, Ministry of Agriculture, Forestry and Fisheries, Japan. 1995. Rice post-harvest technology.
  4. Grochowicz, J. 1980. Machines for cleaning and sorting seeds. Machines for cleaning and sorting seeds.
  5. Kawamura, S., K. Takekura, J. Himoto. 2006. Development of a system for fine cleaning of rough rice for highquality storage. ASABE Annual Meeting.
  6. Kim, J. G. 2001. Basic study for the development of a precision broken rice separation process in the RPC. MS thesis. Jeonju, Korea: Chonbuk National University, Department of Bio-industrial Machinery Engineering (In Korean, with English abstract).
  7. Koh, H. K. et al. 1995. Rice Processing Complex - Theory and Practice. Seoul, Korea: Moonwundang. (In Korean)
  8. Korea Rice Technical Working Group. 2005. Strategies for Increasing Rice Consumption. Korea Rice Technical Working Group 19. (In Korean).
  9. Kuprits, Y. N. 1967. Technology of Grain Processing and Provender Milling. Israel Program for Scientific Translations Ltd., Jerusalem, Israel.
  10. Nguyen, H., K. Goto, R. Yamashita. 1987. Study on separating of shape by using test rice grader (Part 4) - Separating characteristics of rough rice and brown rice by indented cylinder separator. J. of Japanese Society for Agricultural Machinery 49(3):207-216 (In Japanese, with English abstract).
  11. SAS. 1999. SAS/STAT User's Guide: Statistics. Ver. 8. Cary, NC: SAS Institute, Inc.
  12. USDA. Agricultural Marketing Service. 1976. Inspection Handbook for the Sampling, Inspection, Grading, and Certification of Rice.
  13. Yamashita, R., H. Yoshitomi, K. Goto, H. Nguyen. 1979. Study on separating by shape using test rice grader (Part 1) - Analysis of separating mechanism for indent cylinder type. J. of Japanese Society for Agricultural Machinery 41(3):455-461 (In Japanese, with English summary).
  14. Yoshitomi, H., R. Yamashita, K. Goto, H. Nguyen. 1980. Study on separating of shape by using test rice grader (Part 2) - Factors of separating and catching probability by indent cylinder type. J. of Japanese Society for Agricultural Machinery 41(4):603-609 (In Japanese, with English summary).