Many bulk materials, especially fine powder, are cohesive and do not flow consistently out of the supply hopper during feeding. Such poor flow properties can lead to the formation of rat holes or even material bridges, making it difficult to accurately deliver these materials to the process. A rat hole is a narrow vertical tunnel from the top of the material bed in the hopper to the discharge device of the feeder. Although material can continue to flow through the hole, the discharge rate of the feeder is lowered considerably and bulk material may deposit in the hopper. Material bridges similarly restrict the flow of material. Since bridges lack even the vertical tunnel of a rat hole, the material flow tends to be completely blocked. Vertical agitators can be used to prevent ratholing and bridging of bulk material. Although this system is dependable, it requires additional headroom above the feeder, and cleaning is awkward, laborious and time consuming.
Staying in the Flow
The ActiFlowTM system overcomes the disadvantages of a vertical agitator. The smart flow aid device applies gentle vibrations to the hopper wall, hereby carefully activating the contained material with the optimal amplitude and frequency. The ActiFlow control module constantly communicates with the KCM feeder control to ensure an ideal material flow in the hopper and maintain a very high feeding accuracy. The filter algorithms in the load cells or the platform scale effectively filter out vibrations, thus guaranteeing an exact weight signal at all times – even when the ActiFlow’s bulk material activation is at its maximum. ActiFlow eliminates headroom concerns, reduces cleaning and product changeover time and in turn lowers overall production labor cost.