Cutting the extrudate
When leaving under high pressure the barrel through the die-plate, the flour will form strings of dough. As seen in the previous topic, “extruding”, the dough will swell due to the pressure drop and sudden evaporation of water.
These strings however are not the desired shape for fish feed, which is why they are cut at the desired grain length, immediately after leaving the mold.
Cutting the strings is done by fast rotating blades which are mounted on an axis. The blades are shown on the image below, in between part of the Archimedes screw on the left and the die-plate on the right.
The length of the pellet can be set by adjusting the rotation speed and the number of blades in action.
The pellets are then sucked pneumatically or transported through a conveyor belt in order to reach the dryer.