Power, force feeder

Roll and/or force feeder power. To do the required compaction work a certain power input is necessary which must also overcome the losses in the drive system. It was determined that the powder drawn by the roll drive motor(s) is a relatively sensitive indication of the actual work done by the rolls and, therefore, the quality of the product. In machines with fixed rollers the amperage is also a measure of the roll force. 

If a force feeder is used, the power drawn by the motor driving this device determines the pressure in the material above the compaction zone. 

Ring mills consist of a power-driven rotating ring with radial holes, friction rolls to force the material holes and knives to cut the extrudate to the desired lengths. See Figure 12.16(a). The feed is charged with screw feeders into spaces between the rolls and feed... 

The feeder has to function with a volume of material in the bin above it. Obviously, if there is not always a positive volume of material it cannot produce a controlled output, and it is therefore not a feeder. Usually, the bin has a converging flowpath, say a cone, where it joins onto the feeder. The geometry, construction, and surface roughness of this flowpath affects the rate at which material can flow into the feeder, the vertical load transmitted onto the feeder, and the power required to drive the feeder. In the converging flowpath, frictional forces oppose the oncoming load of material, relieving the pressure apphed onto the feeder. 

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