Fish Nutrition & Feed Technology

Unit 10 - Methods of feed formulation and manufacturing

10.5.7.Screening or Grading

Some sifting is necessary in the production of pellets and crumbles. Small fragments (fines) are produced as hot, moist pellets are cut off from the die inside the pellet chamber, and as pellets pass through the cooling and conveying equipment. Fines may be returned to the pellet mill for reprocessing or used as feed for fry.

There are many types of sifting and grading systems both manual and mechanized. Most shake or rotate from side to side with material passing over screens of specified openings and covered to confine dust to the equipment. Sifting is the last process in manufacture of pellets and crumbles and this equipment should be located just above the bagging or final discharge bin.