Miller Magazine Issue: 154 October 2022

63 COVER STORY MILLER / OCTOBER 2022 the quantity of ferrous metal weighed and recorded, fragments of metal in the wheat flow can causes irreversible damage to machinery and cause sparks that can then result in dust explo- sions and fires. BI FLOW RATE AND DISTRIBUTION Ensuring even distribution of the feed, across the entire roller length is critical to the mills efficiency. The best method of en- suring this is by weighing the grind of all like rolls then making the necessary adjustment. Unbalanced like rolls has an impact on the efficiency of the plansifters and mixing of stocks to the purifiers. Measuring the moisture content and HLM of the feed to the rolls will provide the miller with the potential extraction possible from the grain. Target moisture content must be ob- tained and maintained through the run. Inspection of the roll fluting at regular intervals for wear is necessary. This is to ensure that the required releases are achieved every time without increasing the energy demand. Worn roll surfaces require more energy to achieve the desired results and, cause flaking of the endosperm particles against the larger bran particles. This segment of the feed then flows to the second break where the effort in removing the endosperm often results in the generation of bran powder and a subse- quent increase in the ash content of the flour. Regular inspection will alert the miller of the need for roll changes. Replacing rolls with the correct flutes and roll dispo- sition is critical. Do not use rolls with different fluting because you don’t have stock. Note must be taken that smooth rolls require taper to avoid over expansion of the ends of the rolls causing the stock pass- ing through the middle of the roll length with ineffective grind- ing of the semolina, especially in the head reduction passages. Shiny smooth rolls do not have the abrasive surface needed to crush the endosperm to a fine powder. Inspection of the separations of the sifter allocation and com- parison provides a good guideline for the miller, relating to the settings of the purifiers, for thorough efficient separation of the various particle sizes of the semolina, to be ground into sale- able high-quality flour. Sifter separations are more often than not, not carried out by the mill operative/ miller, resulting in him/her running around the mill when the laboratory personal call them with production errors in flour quality. The subsequent result of the lack of sifter inspection is the stock to the purifiers, contaminated with bran adhering to the endosperm and the miller spending valuable time trying to adjust the machine instead of identifying the root cause of the problem. (Poor sifter separations or unnecessary excessive roll grinding due to worn rolls.) Again, balancing the feed to like rolls is an important aspect of the head reduction process so the flour produced here is of uniform quality off the plansifters allocated. Incorrect roll adjustment often has the miller running around the mill try- ing to correct the flour quality instead of ensuring correct re- quired machine setting. Inspection and adjustment of smooth