FLOW CONDITIONS IN ROTARY IMPELLER PACKERS

The rotary impeller filling system has been used for bagging cement since the start of the 20th century. Alternative designs were developed in the mid 80s, and were also put to the test under practical conditions. The flow conditions in the turbine impellers were investigated in scientific trials and the measurements were evaluated with the aid of well-known fundamental equations. The optimization which this made possible was utilized to make a significant improvement in the bagging capacity with products with finenesses of over 10000 Blaine and to achieve a considerable decrease in wear. In the meantime, practical tests were carried out which fully confirmed the numerical calculations and the experimentally determined data. A new electronic weighing system was also developed which, in a cycle of 23 ms, measures the mass flow continuously and calculates and optimizes all parameters for the changeover between coarse and fine flow as well as the run-on correction. Any change in the flow behaviour of the product is determined within this cycle time. All the parameters are then adjusted independently to the situation so that exceptional weight accuracy is guaranteed when the bagging machine is operating at full capacity. Automation modules such as empty bag applicators and automatic palletizers are available to make continuous use of the full capabilities of the new packer; these automatically undertake any changes in product, bag weight or stacking pattern.