Miller Magazine Issue: 119 November 2019

79 ARTICLE MILLER / NOVEMBER 2019 controlled by container volume and/or the amount of time the sample is taken. Weighing of the sam- ple must be done in a manner that will not result in size separation. Accurate weighing of the sample is important, as well as accurate weighing of the separate components after test sifting (Posner and Hibbs, 2005). Sifting Proper test sifter procedures are important in determining break or grinding releases from roller mills. The test sifter used must be large enough to process the entire sample collected (Fowler, 2012). Break releases were originally monitored by us- ing a hand-held sieve to mimic the coarse sepa- rations of the sieve or centrifugal. More recently, a mechanical sieve, which has a pre-set timing device, is commonly used. Accordingly, the miller selects for break release adjustment sieves with apertures similar to those used at the top of the corresponding break sifters sections in the mill and sift each sample the same amount of time (Posner and Hibbs, 2005; Fowler, 2012). Appropriate sift- ing time can be determining by sifting in 10-second time increments and determining when less than a 1% change in through stock based on the original sample weight has been identified, with the sample screen remaining clear and no fines observed in the over tail (Gwirtz, 2018). Generally, the stock over the screen is weighed and subtracted from the original sample weight to calculate the weight of the through stock that can be expressed as a percent of the original sample weight (Gwirtz, 2002). In new developments millers take different ap- proaches to automatically determining the break release on-line. The test sifters are modified for continuous on-line separation of ground material to overs and throughs, and the weights of those are used to determine the break release and to activate roll gap adjustment. Another approach is to deter- mine the weight of one of the sifter outlet materials continuously with a flow-through scale and feed- back information to the roll gap control (Posner and Hibbs, 2005). An innovative solution for monitoring the granula- tion distribution is with Particle Size Measurement (PSM) apparatus, which can be either installed fixed in a plant or as a portable. Particle Size Meas- Asia’s largest animal feed event For more information, please visit: www.victamasia.com BITEC Bangkok, Thailand 24 - 26 March, 2020 VICTAM ASIA is firmly established as the event dedicated to the animal feed processing industry within Asia. Co-located with VICTAM ASIA is GRAPAS ASIA, the event for the grain and rice processing industries. VIV Health & Nutrition, the event for feed, pharma & genetics in the animal protein production, will also be co-located with VICTAM Asia 2020. Victam Corporation T: +31 33 246 4404 E: expo@victam.com W: www.victaminternational.com See us on Twitter, Facebook, LinkedIn and Google+ or scan the QR code Supported by Thailand Convention and Exhibition Bureau (TCEB)