Developments in grain conditioning equipment

by Teresa Acklin
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Automatic moisture control key to assuring quality.

   Grain mills are finding it increasingly important to maintain quality criteria accurately throughout the process. This includes the continuous correction of the water addition rate until the desired grain moisture is achieved exactly, which offers the additional benefit of higher efficiency.

   Buhler Ltd., Uzwil, Switzerland, has launched a new automatic moisture control system whose operation is based on safe microwaves. The system regulates the desired moisture content based on measuring the grain that has just been dampened. Moisture content is determined by the new MYFB moisture tester, which relies on microwave measuring techniques rather than hazardous gamma rays.

   The most important system component in grain conditioning is the automatic moisture control unit. The MYFB online moisture tester analyzes the wheat stream on a continuous basis and allows the water metering rate to be regulated. The relevant digital data can be tracked on the control unit or on a master system.

   The MYFB moisture tester is one of five components in Buhler's complete automatic moisture control system. Depending on the application, other components are:

   • the Transflowtron MWBG mass flow meter or the MWBL input batch scale for measuring and regulating material flow rate;

   • the MOZE liquid flow rate controller for metering the calculated quantity of dampening water, which ranges from 10 to 2,500 liters per hour;

   • the MYEB control unit for calculating and regulating the required water quantity; and

   • the MOZK tri-rotor dampener for achieving maximum dispersion and penetration of the dampening water throughout the grain while minimizing wheat abrasion and breakage.

   The combination of all five system components allows fully automatic regulation of material moisture on the basis of the feedback or feedforward process (measurement after or before dampening). The Transflowtron MWBG differential proportioning scale is particularly suitable for determining the current material throughput rate, but the Tubex batch scale or the automatic flow balancer also may be applied for this purpose.

   The MYFB moisture tester is installed in a bypass adjacent to the main stream of cleaned wheat. Its mechanical design incorporates the latest findings from the field of food processing sanitation, and all parts in contact with the material are made of stainless metals. In addition, all elements through which grain passes have been streamlined to minimize the risk of material deposits.

   The MYEB control unit enables users to control simultaneously up to four metering systems in various configurations thanks to its user-friendly menu structure. The unit can be controlled remotely from a master system through an RS-485 interface.

   All process data are available whenever needed, and the master system also can access the data. Any production errors are detected immediately and can be eliminated in good time thanks to the monitoring of various tolerances and the online measurement method.

   The MOZE liquid flow rate controller ensures precise metering of the desired water quantity. This water is fed to the MOZK tri-rotor dampener, which is normally installed in the material stream ahead of the moisture metering section.

   The cleaning system and the new moisture regulation system enable solutions tailored to the customer's needs. Different cleaning concepts permit individual adjustment of the process to the particular wheat varieties processed, the available storage facilities and the range of finished products.