Miller Magazine Issue: 113 May 2019

51 COVER STORY MAY 2019 material to each piece of equipment. Drawing it is rather simple. Just use the example sym- bols and lines from the picture above (or make up your own) and tell yourself what they do. First stage: Draw a symbol for each one of your ma- chines. Second stage: Annotate each symbol with the chara- cteristics of each machine. Third stage: Decide what you want to achieve. Fourth stage: Play around with the diagram to see how you can achieve it. To master the flow sheet you must know some basics of the process, and why the specifications of the mac- hines are important. Milling consists of five sub-systems: 1. Breaks. 2. Sizing. 3. Middlings. 4. Low grades. 5. Tailings. What the flow sheet does is showing the connections between those stages and the individual machines. The objective of milling is separating the endosperm from the germ and the bran. Breaking of the wheat kernel is done using corrugated rolls. Reduction of the endosperm fragments to smaller particles (less than 180 microns) is done using smooth rolls. Segregation of the particles is done in sifters and purifiers. Sifters classify particles according to size. Purifiers use sieves and air to classify according to size, density, and shape; separa- ting pure endosperm from fragments that contain both bran and endosperm. Flour extraction of the mill is measured as a quotient between the flour produced and the grain used. The