RESEARCH NOTES: The Numerical Evaluation of the Frequency Response of Optical Systems

A die for use in a food chopper downstream of the coarse-cut die is formed with an array of like small-diameter holes and on each of its faces with an array of grooves having a width substantially greater than the diameter of the through-going holes and extending at an angle to the blade which sweeps over the upstream face of this die. Particles which have passed through the upstream die and which are unable to pass through the small-diameter holes in the downstream die are caught in the grooves and cut between the downstream edge of the grooves and the cutter blade. These grooves are arrayed such that the cutter blade conducts the food along the grooves, and the grooves may be of decreasing depth in the direction of travel of the material therealong so as to allow the material to be reduced to very small size. At the inner ends the grooves may terminate in large-diameter throughgoing holes which are connected to an arrangement for carrying unchoppable particles out of the chopper.