Gericke, Regensdorf, Switzerland, points out that precise metering with high levels of repeatability can prove very challenging with bulk products which have a tendency to flush, bridge or compact such as icing sugar, calcium hydroxide, fibres or flakes. The mechanical design and shape of a feeder has a major influence on its capability and reliability to handle difficult products. Gericke has accumulated a large knowledge base by conducting field and testlab trials and converting the findings into the design of its entire feeder product range. For example, to mitigate the phenomenon of bridging, feeders from the GAC and GDU series offer an over-dimensioned entry section. Various types of agitators or homogenizers or even vibrated hoppers or ultrasonic induced energy are used for homogenising the bulk material in the feeder hopper and to introduce the particles into the feeding auger or helix in a constant manner. These are some of the basic pre-conditions for accurate and repeatable volumetric feeding. 

 

The profile of the helixes and spirals plays a significant role as well. This very important part of each feeder has to be adapted to the respective process and product characteristics. It influences the filling degree, the compression and mechanical stress on the product, while at the same time helping to avoid flushing or pulsation at the outlet. Rheology analysis can be performed at the company’s laboratories and feeding trials with specific accuracy measurement software are available at its test centres. www.gericke.net 

 

 

Gericke batch weighing system