Milling Journal - Q1 2008 - (Page 21)

chines. Oftentimes, one purifier is used for coarse stocks. Another is used to purify fine stocks. The third purifier receives stocks from third break. Purifier Disadvantages There are some disadvantages to operating mulitple purifiers in the millflow. • Purifiers have high capital, operating, and maintenance costs. • Purifiers have low capacity per unit of floor space. • Changes in loads of stocks to the purifiers can cause the milling process to become unstable. • The special ventilation and dust-collection systems required by purifiers add to capital, operating, and maintenance costs. • The air used for stratification has a tendency to dry the middlings. This can increase bran breakage in the reduction and tailing systems, thereby increasing ash content. • Millers must make constant adjustments to purifiers to prevent instability. Additional adjustments are needed when there are changes in wheat mixtures, tempering, or humidity in the mill. • Without proper housecleaning, purifiers can contribute to hygienic problems because of their complex structure. The Possibility of Going Purifierless To overcome these disadvantages, many companies have tried designing millflows without purifiers. In older mills, which featured dated plansifters that worked at a low capacity, it was impossible to produce a low-ash patent flour without using purifiers. Since then, the sieving process has improved, and the plansifters now work at a higher capacity. Advancements such as this now make it possible to produce straight-run soft flour without using purifiers in the flow. A modern high-capacity plansifter is capable of stratifying the stocks in much the same way a purifier does. However, a sifter does need an advanced air-makeup system. By carefully planning the millflow, a purifierless mill can produce low-ash patent flour and fine semolina. The figure on page 22 shows a typical purifierless millflow. At our mill, we produce a low-ash patent bread flour by taking clear, speckfree flours from 1st sizings, 1st middlings, 2nd middlings, 3rd middlings, 2nd break, and the break redust sifter section. These sections yield approximately 88% of the flour with 0.448% ash. The remaining 12% of the flour is somewhat brown with approximately 0.85% ash content. To achieve results such as these, you must optimize sifter surface allocation, cover numbers, roll fluting, roll spirals, and roll differentials. Removing the Purifiers At the “Shalom” Flour Mill, we used to run a traditional millflow with six purifiers. In 1982, the mill was enlarged and modernized with high-capacity square plansifters. We reduced the purifier section to only two machines. We were able to remove the two purifiers from the flow after two years of experimenting, which involved changing parameters such as surface allocation, sifter cover numbers, roll fluting, roll spirals, etc. We now have one purifier in the mill. It is used only when we want to produce coarse semolina. With this setup, we have been able to eliminate the disadvantages that were mentioned previously. This system has worked so well for us that we utilized the purifierless flow in our 2000 mill expansion. Response No. 211 MILLING JOURNAL First Quarter 2008 21 http://www.vigenconstruction.com http://www.vigenconstruction.com http://www.vigenconstruction.com

Table of Contents Feed for the Digital Edition of Milling Journal - Q1 2008

Milling Journal - First Quarter 2008 Contents First Break Examining Fortification Standards IAOM 2008 Milling Short Courses 2008 IAOM Conference and Expo Melinda Farris Interview Designing a Purifierless Millflow Dirk Maier Named KSU Dept. Head NAMA’s 2008 Division Meetings Protecting Electrical Workers Miller Profiles Todd Bastean Interview Safety: How Serious Are We? Product Quality/Gwirtz Product Roundup: Magnets Pest Management/Subramanyam Explosion Protection Supplier Interview: Darin Stutler Product Reviews New IAOM Safety Award Criteria Don’t Forget OSHA Form 300A Milling Notes Great Lakes Regional Conference 4th Quarter 2007 Flour Production IAOM Reference Guide Hammermills Brushes Aspirators Level Indicators Product Reviews Magnets Mixers Packaging Purifiers Safety Equipment Screeners Separators Sifter Accessories Ad Index

Milling Journal - Q1 2008

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