The refiner function is to remove the impurities such as skin, pin bones, scales and connective tissues from washed fish meat by filtration through a screen.  The fish meat drained by a rotary screen with a moisture of 89 to 90% is dropped into the receiving side of the refiner and carried by a screw to the sieving section where rotating blades throw it against a screen with 3 or 4 sections.  The meat is pressed through the screen by the centrifugal force applied by the rotation of the blades while the impurities are retained and ejected at the end of the screen.