In sugar production, sucrose is extracted from sugar beets. On arrival at the production plant, the sugar beet roots are washed and cut into thin strips. These are passed into a diffuser that immerses them in hot water to extract the sugar content. The diffuser separates the pulp from the liquid. The liquid exiting the diffuser is called raw juice and is used to retrieve the sugar by evaporation. The used beets (pulp) are still very wet, with small quantities of sugar remaining in the water inside them.
To recover these sugar residues, the pulp is inserted into a screw press. The screw press is a slow-moving mechanical device in which a conical screw rotates inside a perforated cylindrical filter. During the pressing phase, the pulp is pressed with increasing force against the metal filter in order to obtain as much juice as possible. The holes in the filter allow the water to drain out. The remaining water is collected and used as diffusion water while the remaining beet pulp is used as livestock feed.
In sugar production, the Costacurta drilled plate (that forms the filter of the screw press) is a fundamental element of the machine. The plate must have a high thickness to resist pressure, and different kinds of perforations (cylindrical, conical and step drilled) that allow the filtration of water and its separation from the solid pulp.
In the production of drilled plates for sugar production, the quality of the material used and the precision of the perforations are crucial elements for guaranteeing efficient filtration.