The screw press is used for various purposes in the surimi process and its specifications respond to these different usages. The compression ratio of the screw conveyor (2.5:1 to 5:1) and the speed of the screw conveyor are adjusted depending on the purpose of the screw-press and the amount of water to be removed.
– Dewater recovery meat from nylon mesh screens: since this meat has high moisture (95-96%) and must be dewatered to 80-82% (solids increase from 4-5% to 18-20%), it requires a small screw press with high compression ratio (5:1) working at low speed (capacity 200-300 kg/h).
– Dewater rotary screen meat after the first wash: the purpose is to remove the dirty water carried with the meat to reduce the water consumption in the next washing steps. In this case a small screw press with compression ratio of 2.5:1 working at high speed is used to remove 70% of the free water in the meat and reduce moisture from 89-90% to 86-87% (capacity 3 to 5 MT/h)
– Dewater refiner meat before the big screw press: the purpose is to remove the remove 70% from the meat and reduce moisture from 90% to 86-87% to facilitate the final dewatering by the big screw press and increase the capacity of the line. It requires a small screw-press with compression ratio 2.5:1 working at medium speed (2 to 3 MT/h)
A counter-pressure ring is used in the beginning of the operation to form a plug of dewatered meat at the end of the screw that will insure pressing of the meat in the screw press.