The refiner function is to remove the impurities such as skin, pin bones, scales and connective tissues from a slurry of fish meat and water by filtration through a screen. The slurry is pumped into the receiving side of the refiner and thrown onto the cylindrical screen by rotating blades. The meat is carried with the water through the screen usually with 1.2 to 1.5 mm holes while the impurities are retained by the screen. The blades have a helix shape that carries the impurities to the discharge at the exit side of the refiner.
The refiner is equipped with a spray system that can be used to help the blades push the impurities through the refiner and prevent vibrations of the machine that occur when impurities are not properly carried out to the discharge.