Miller Magazine Issue: 119 November 2019

78 ARTICLE MILLER / NOVEMBER 2019 1) Optimize mill performance by keeping the balance of the mill at fluctuation resulting from conditioning or changes in the mix which led to changes in quantity of sizing, middlings and flour of streams of the early stages of the milling process. Optimizing mill performance led to obtaining high quality and consistent flour at maximum mill capacity and flour extraction. 2) To evaluate roller mill performance over a period of time. In the other worlds, to monitor the wearing factor of roll flutes. As roll fluting wears, the release lessens, therefore the miller must exert higher pressures on the rolls to try to achieve the desired amount of fine product from the break system. This will require a higher input of power which in most modern mills can be readily moni- tored by Amp meters on each roll drive motor. HOW CAN BREAK RELEASES BE MONITORED? Break releases measurement method should be con- trolled and uniform to avoid variation in test results unless data is of no value. The head miller has to train the pro- cedure and ensure the same procedure and equipment is used each and every time, without exception (Bunn, 2000; Fowler, 2012). Sampling Taking the sample for sieve analysis can be a challenging act that demands some experience. Representative sam- ples are taken under the grinding rolls in such a way that a truly representative sample of the flow can be repeatedly ob- tained. A sample should be taken from under the rolls from each side of the ground material stream and if necessary, from the middle, the sample must be collected in a consist- ent manner (Bunn, 2000; Fowler, 2012). Some millers use specially designed containers equipped with a cutting lid to take a fixed volume of material under the rolls. Containers of different volumes are used for different materials. The weight of the total sample is recorded and used for the break re- lease test (Posner and Hibbs, 2005; Fowler, 2012). The collected sample can be sifted directly as is or weighing out a small portion of it. The first way which use the entire sample prevents segregation but requires col- lecting comparable sample sizes and performing calcu- lations to determine the percentage through the screen. Weighing out a small portion of a sample taken under a roll stand prevents calculations but might cause vibration and unintentional segregation in the sample (Bunn, 2000; Fowler, 2012). Finer particles will settle to the bottom of the sampling container. Weighing off or sub-sampling of the original sample most likely will result in a break re- lease calculation that is lower than the actual break re- lease (Fowler, 2012). Accordingly, the whole sample of about 100-200 g should be sifted. Sample size can be